Patent Application
20230159895
The present disclosure provides strategies to assess and/or produce cell populations with predictive engraftment potential. The cell populations can be used for a variety of therapeutic and research purposes.
Hematopoietic stem cells (HSC) are the basis for all therapeutic cord blood, bone marrow and mobilized peripheral blood stem cell transplantation approaches, and blood stem cell gene therapy approaches. HSC transplantation can be curative in many non-malignant and malignant disorders, however, even in transplant centers, the current gold standard for isolation, manipulation and expansion of HSC is through use of the CD34 protein on the cellular surface of HSC. Singular use of the CD34 HSC cell surface marker leads to a mixed or heterogeneous population of cells that have distinct phenotypes and characteristics. Due to the heterogeneity of the cell population, there are several major limitations with using CD34 to identify HSCs (1) the absolute numbers of CD34-expressing cells in blood and bone marrow therapeutic products do not quantitatively correlate with clinical kinetics of patient hematopoietic recovery, which leads to unpredictable clinical results, sometimes resulting in engraftment failure, (2) the CD34-expressing cell phenotype does not predict self-renewal, proliferative capacity or blood cell lineage potential, which is required for a normal and balanced hematopoietic compartment, including the immune system, and (3) the numbers of CD34-expressing cells isolated from blood and bone marrow products require large volumes of reagents for manipulation, which can be cost prohibitive if genetic manipulation of the HSCs is required. For example, the volume of genetic manipulation components (e.g., lentivirus) required to transfer a therapeutic gene of interest can encompass up to 25% of a standard production lot of these components. Thus, the field has widely recognized that there continues to be an unmet need to identify a more enriched, true HSC population. Others have identified alternative HSC protein surface markers to enrich for true HSCs, however, they still fail to predict engraftment potential.
The present disclosure provides strategies to assess and/or produce cell populations with predictive engraftment potential in transplantation. The cell populations can be used in the development and deployment of therapies, among other uses. Methods described herein allow processing and isolation of cells with particular marker profiles that contribute to the predictability of engraftment. The current disclosure also describes methods to process and isolate hematopoietic stem cells (HSC) and multipotent progenitor cells (MPP) from humans and HSC, MPP, lympho-myeloid progenitor cells (LMP), erythro-myeloid progenitor cells (EMP) and myelo-megakaryocytic progenitor cells (MMP) from non-human primates.
In particular embodiments, populations of HSC with predictive engraftment potential can be isolated by selecting for CD34+ cells from the cell source, and sorting for the CD34+ cell population which is negative for the cell marker CD45RA and positive for the cell marker CD90 on the cell surface which is conserved between humans and nonhuman primates. In particular embodiments, populations of HSC with predictive engraftment potential can be isolated by using the additional cell surface markers of CD133 (human) or CD117 (non-human primate). Each of the foregoing subsets of CD34+ cells have self-renewing capacity, multi-lineage potential, long-term engraftment capability and, most importantly, predictably correlate (quantitatively and/or logarithmically) with hematopoietic recovery after transplantation. As an overview of the predictive nature of engraftment of the developed cell populations, compare
Moreover, the engineering procedures described herein can be applied to embryonic stem cell (ESC), pluripotent stem cell (PSC) and induced pluripotent stem cell (iPSC) therapeutics. These phenotypes can be used to generate engineered cell therapeutics or could be used as a target population for differentiation of previously engineered stem cells such as ESC, PSC and iPSC. The phenotypes described could serve as a measure of success and potency of such engineered cell therapeutics. Additionally, non-engineered cell therapeutics such as platelets, macrophages, red blood cells or other blood cells, could be generated from the cell populations defined herein.
Due to cytomegalovirus (CMV) infection and early euthanasia, no long-term follow-up is available for animal Z13314. Due to engraftment failure requiring early euthanasia, no long-term follow-up is available for animals Z13251 and Z13125. Due to kidney failure, no long-term follow-up is available for animal Z14160. The day of necropsy is indicated by the dashed vertical line in
Long-term follow-up was not available for the reasons stated as described in relation to
The total number (sum of condition 1+2+3) as well as the cell count/kg body weight of CD34+ cells, HSC-, MPP- and LMP-enriched fractions for each NHP is summarized in Table 3 and 4.
Lack of anti-CD45RA staining did not allow for a discrimination and quantification of MPP- and LMP-enriched fractions for animal R11145.
For more than three decades, hematopoietic stem cell (HSC) research has been performed based on the classical model of human hematopoiesis. This widely accepted model suggests an early segregation of lymphoid and erythro-myeloid potentials into a common lymphoid progenitor (CLP) and a common myeloid progenitor (CMP), respectively (Galy et al., 1995; Manz et al., 2002). However, this model has been challenged by proposals of a great variety of alternative lineage relationships and read-outs for multipotent HSCs, including but not limited to the cell surface markers of CD38 and CD49f (Adolfsson et al., 2005; Doulatov et al., 2010; Görgens et al., 2013; Notta et al., 2015; Masiuk et al 2017; Zonari et al 2017, US 2012/0252060). The hypothesis based on the current model of hematopoiesis (see
Using the cell surface marker CD133, one revised model of human hematopoiesis proposes that HSCs and multipotent progenitors (HSCs/MPPs: CD34+CD45RA−CD133−) give rise to lympho-myeloid progenitors (LMPs: CD34+CD45RA+CD133+) and erythro-myeloid progenitors (EMPs: CD34+CD45RA−CD133low) (Görgens et al., 2014; Görgens et al., 2013; Radtke et al., 2015). This model suggests that multipotent HSCs/MPPs can easily be identified as CD34+CD45RA−CD133+ HSPCs with erythroid differentiation potential.
Clonal analysis and comparison of RNA expression profiles of human HSPCs from fetal liver, umbilical cord blood (UCB), and steady state bone marrow (ssBM) further revealed a shift in hematopoietic lineage relationships during development and aging (Notta et al., 2015). Primarily focusing on the lineage relationships of primitive HSCs/MPPs and erythrocyte/megakaryocyte progenitors, Notta et al. have redefined the hematopoietic model, proposing an early separation of megakaryocyte potentials in adult stem cell sources (Notta et al., 2015).
While hematopoietic lineage relationships are still under investigation, consequences of these findings on the development of treatment strategies for hematological diseases and malignancies are rarely discussed. A critical factor for the development of allogeneic and autologous stem cell therapies is the availability of a read-out for multipotent HSCs/MPPs supporting the development of all blood cell lineages. Unfortunately, the current gold standard, the NOD/SCID mouse repopulation assay, does not support erythrocyte and megakaryocyte development and, thus, does not accurately read out multipotent human HSCs/MPPs (Mazurier et al., 2003). In addition, development of therapeutic approaches with human HSPCs in the mouse model is not possible due to differences in marker expression, physiology, life span, and the demand on stem cell self-renewal and differentiation compared to humans (Larochelle et al., 2011).
Development of clinical treatment strategies is currently performed in large animal models such as the dog and nonhuman primate (NHP). The pigtail macaque (PM; Macaca nemestrina) and the rhesus macaque (RM: Macaca mulatta) share a close evolutionary relationship with humans and have been used as a pre-clinical model system to study basic HSC biology (Shepherd et al., 2007) or to develop specific HSC gene therapy approaches (Peterson et al., 2016). Surprisingly, however, a comparison of hematopoietic subpopulations and the hierarchical organization of defined lineages has not been performed between NHPs and humans. This is a critical factor for a better understanding of the newly defined blood lineage associations and hierarchies, as well as the development of treatment approaches based on these lineages.
Stringent development and confirmation of a true HSC phenotype cell population can only be achieved after robust multilineage reconstitution of an irradiated recipient. Of the various models developed, retrovirus transduction and subsequent transplantation of CD34+ cells into human or animal recipients has permitted tracking of tens of thousands of individual cells in vivo over time and lineage development (Bystrykh, et al., 2012).
The current disclosure shows that in the NHP, megakaryocyte and erythrocyte lineages branch off independently from a multipotent progenitor (MPP: CD34+CD45RA−CD90−CD117+,
Understanding hematopoietic lineage relationships is not only important for the basic understanding of stem cell biology but also critically important for rationally designing new therapeutic applications and strategies. Within the last decades, a great variety of cell surface markers have been reported for the identification and enrichment of human HSCs (Masiuk et al., in press; Zonari et al., 2017; Doulatov et al., 2010; Görgens et al., 2013; Kikushige et al., 2008; Lansdorp et al., 1990; Majeti et al., 2007; Notta et al., 2011; Terstappen et al., 1991). The conclusion from these studies has been that human HSCs are found to be enriched in CD34+CD38lowCD45RA−CD49f+CD90+CD117+CD133+ fractions (
Described herein is development and processing a CD45RA−CD90+ subset of enriched CD34+ cells for rapid multilineage hematopoiesis in a clinically relevant NHP autologous HSC transplantation model. Evidence for early-engrafting HSC-like clones which are stably maintained long-term are demonstrated. The disclosure is supported by tracking hundreds of thousands of unique clone signatures in animals over years of follow-up. Most importantly, we demonstrate the phenotype and transcriptomes of these cells are highly similar between NHP and humans. Biologically robust competitive repopulation experiments in four animals demonstrate the capacity of CD34+CD45RA−CD90+ cells to completely reconstitute hematopoiesis in the transplant setting. The current disclosure also provides that many fewer cells are needed for successful hematopoietic reconstitution in this setting (122,000 cells/kg) as compared to the 5-10 million cells/kg typically required for CD34+ cells, the current clinical gold standard for HSC enrichment. The number of nonhuman primates described in this disclosure, validation of in vitro biology in vivo both retrospectively and prospectively, and the tracking of individual clones to confirm the disclosure supports early HSC engraftment and clonal stability after transplantation. Most importantly for the fields of HSC biology/transplantation, gene therapy and gene editing, this disclosure develops and processes a highly refined and markedly reduced cell population capable of completely functional hematopoietic reconstitution.
The current disclosure provides that the disclosed highly HSC-enriched CD34+CD45RA− CD90+ cell population is accountable for all gene-modified cells observed in PB and BM following transplant. This shows that everything required for short- and long-term, multilineage hematopoietic reconstitution is contained within this engineered cell population. The limitations of methods in the prior art is that the enriched-HSC populations were not sufficient to re-populate all of the hematopoietic lineages, meaning, practitioners would need to add additional cells during their preparations. See, e.g., Kohn et al., 2010. By having a clearly defined cell population as disclosed in this patent application, the manufacturing of cell and gene-modified therapeutics could be streamlined leading to faster processing of stem cell sources and reduced reagent needs for cytokines, consumables and modifying agents (such as vector, nucleases or other reagents). These are critical requirements if stem cell and gene therapy will translate outside of specialized academic medical centers and be utilized in a broader setting.
The disclosed cell populations have a major impact in the development of novel HSC-based therapies. The NHP model offers a read out of hematopoiesis which is not possible in small animal models such as the mouse, process and enrich multipotent HSC, and determine their multi-lineage engraftment potential in a clinically relevant transplant model. Furthermore, it allows scale-up of cell isolation and manipulation protocols, testing of safety and off-target effects, evaluation of the development of all hematopoietic lineages, as well as long-term engraftment follow-up in a pre-clinical transplant setting with high homology to humans.
In vivo observations in competitively transplanted animals show that the selection of the CD34+CD45RA−CD90+ cell population is a significant refinement in the target cell population for transplantation, as well as in approaches such as combining HSC-enrichment with genetic modification for the purposes of gene therapy. Currently, the gold-standard for clinical gene therapy is lentiviral (LV) transduction of enriched CD34+ cells. Focusing on creation of CD34+CD45RA−CD90+ cell populations results in a 20-fold reduction in overall cell numbers and thus dramatically reduces materials required for vector-based or nuclease-mediated gene therapy and editing protocols (
A strong correlation between CD34+CD45RA−CD90+ HSCs/kg body weight and the success of multi-lineage engraftment was achieved, as well as the time to neutrophil and platelet recovery, further supporting the clinical translation of the described, phenotypically defined, HSC-enriched cell populations. This is the first disclosure of a statistically significant and direct correlation of a phenotypically and/or functionally defined HSPC subpopulation with short- and long-term engraftment markers in the transplantation setting. The correlation between CD34+CD45RA−CD90+ cell dose and engraftment was not affected by different stem cell sources, gene modifications, expansion protocols, or cryopreservation, making this phenotype a valuable tool for the in vitro analysis of various novel HSC modifications, expansion strategies and quality control of stem cell infusion products.
In summary, the development of phenotypically and transcriptionally unique cell populations between human and NHP HSPCs and blood lineages is a major advance for the development of novel HSPC therapies. While each of the markers in the profiles described herein is individually known, the processing methods disclosed herein provide a novel strategy that defines HSC capable of providing for both short- and long-term engraftment. Furthermore, the development and processing of the disclosed cell populations results in predictable correlation with the time to hematopoietic recovery of neutrophils and platelets in the myeloablative transplant setting, providing a measure of potency. The ability to predict engraftment failure or success is a critical unmet need in the transplant setting where even with large doses of CD34+ cells as evidenced by our experiments (
The detection of persistent and HSC-like clonal signatures early after transplant, before all lineages have reconstituted, shows our CD34+CD45RA−CD90+ cell population immediately contributes to long-term, multi-lineage hematopoietic reconstitution lasting up to 7+ years in the disclosed clinically relevant model.
These advances also allow for the development and testing of gene modification approaches to correct HSC in non-malignant diseases with monogenetic mutations, such as Fanconi anemia, hemoglobinopathies, as well as pathogen-mediated diseases, such as HIV/AIDS through the disruption of CCR5. Considerations relevant to these aspects of the current disclosure are now described in more detail.
In particular embodiments, the engineered cell population will be administered with or without genetic modification in transplantation. Transplantation is a medical procedure in which a blood or bone marrow donor stem cell source is administered to patients. In order to allow for successful transplantation, conditioning reagents are administered to make room for the new HSC graft. In particular embodiments, a transplant replaces abnormal blood-forming stem cells with healthy cells in both non-malignant and malignant settings. An essential component to HSC transplantation with or without genetic modification is conditioning regimens administered prior to the infusion of the HSC-enriched cell population. Gyurkocza & Sandmaier, 2014. For malignant conditions, such as cancers or tumors, myeloablative conditioning regimens with total body irradiation (TBI) and chemotherapeutic agents with nonoverlapping toxicities are used to provide sufficient immunoablation to prevent HSC graft rejection and reduce tumor. In particular embodiments, TBI is conducted with 4 doses of 255 cGy. In this setting, graft versus host diseases (GVHD) and graft versus tumor (GVT) or graft versus leukemia (GVL) effects contribute to the effectiveness of the HCT transplant. In patient populations that will not benefit from GVHD or GVL/GVT there is added benefit of removing CD45RA+ cells from the infusion product. Removal of CD45RA+ cells from the graft due resulting in T-cell depleted grafts had lower relapse rates in the transplant setting. Bleakley et al., 2015. However, there are significant patient populations, such as older and medically infirm patients, or patients in which the GVT or GVL response is not desired, such as in non-malignant conditions such as monogenetic diseases and cure regiments for pathogen-mediated illnesses such as HIV/AIDS in which non-genotoxic conditioning regimens are being utilized and developed. The field has moved towards reduced intensity and non-genotoxic conditioning regimens for patients, in particular for younger patients in which myeloablative conditioning would cause irreversible developmental harm (Palchaudhuri et al., 2016). In particular embodiments non-genotoxic conditioning regimens include biologic agents such as anti-c-Kit monoclonal antibodies that allow for depletion of HSCs in bone marrow niches in the immunodeficient setting, or in combination with blockade of CD47 using engineered fragments of human SIRPalpha or antibodies that block CD47 activity (Chhabra et al., 2016). In particular embodiments, non-genotoxic conditioning can be accomplished utilizing immunotoxin targeting the hematopoietic-cell-restricted CD45 receptor, in particular CD45-saporin (SAP) (Palchaudhuri et al., 2016)
Stem cell sources include umbilical cord blood, placental blood, bone marrow and peripheral blood (see U.S. Pat. Nos. 5,004,681; 7,399,633; and U.S. Pat. No. 7,147,626; Craddock et al., 1997; Jin et al., 2008; Pelus, 2008; Papayannopoulou et al., 1998; Tricot et al., 2008; and Weaver et al., 2001), as well as fetal liver, and embryonic stem cells (ESC) and induced pluripotent stem cells (iPSCs) that can be differentiated into HSCs. Methods regarding collection, anti-coagulation and processing, etc. of blood and tissue samples are well known in the art. See, for example, Alsever et al., 1941; De Gowin, et al., 1940; Smith, et al., 1959; Rous and Turner, 1916; and Hum, 1968. Stem cell sources of HSC also include aortal-gonadal-mesonephros derived cells, lymph, liver, thymus, and spleen from age-appropriate donors. All collected stem cell sources of HSC can be screened for undesirable components and discarded, treated, or used according to accepted current standards at the time. These stem cell sources can be steady state/naïve or primed with mobilizing or growth factor agents. Stem cell sources can also include hematopoietic stem cell and progenitor cells (HSPCs) that can be further processed to refine HSCs from other progenitor cells.
In order to avoid surgical procedures to perform a bone marrow harvest to isolate HSCs, approaches are emerging to harvest stem cells from the peripheral blood. Mobilization is a process whereby stem cells are stimulated out of the bone marrow (BM) niche into the peripheral blood (PB), and likely proliferate in the PB. Mobilization allows for a larger frequency of stem cells within the PB minimizing the number of days of apheresis, reaching target number collection of stem cells, and minimizing discomfort to the donor source. Agents that enhance mobilization can either enhance proliferation in the PB, or enhance migration from the BM to PB, or both. Mobilizing agents include cytotoxic drugs, cytokines, and/or small molecules. A historically used regimen is a combination of cyclophosphamide (Cy) plus granulocyte-colony stimulating factor (G-CSF). Bonig et al., 2009. Additional mobilizing agents include alpha4-integrin blockade with anti-functional antibodies and CXCR4 blockade with the small-molecule inhibitor AMD3100. AMD3100 is a bicyclam molecule that specifically and reversibly blocks SDF-1 binding to CXCR4. Another embodiment is the combined regiment of GM-CSF or GCSF with AMD3100. In particular embodiments, the mobilizing agent is In certain embodiments, C4, a CXC chemokine ligand for the CXCR2 receptor. GRObeta rapidly mobilizes short- and long-term repopulating cells in mice and/or monkeys and synergistically enhances mobilization responses with G-CSF (Pelus et al., 2006). Furthermore, GRObeta can be combined with antagonists of VLA4 to synergistically increase circulating HSPC numbers (Karpova et al., 2016). In certain embodiments, the CXC4 inhibitor, plerixafor, is used as a single agent for mobilization of HSPCs. Plerixafor is also known commercially under the trade names Mozobil, REvixil, UMK121, AMD 3000, AMD 3100, AMD3000, AMD3100, GZ 316455, GZ316455, JM 3100, JM3100, SDZ SID 791, SDZSID791.
HSC can be collected and isolated from a sample using any appropriate technique. Appropriate collection and isolation procedures include magnetic separation; fluorescence activated cell sorting (FACS; Williams et al., 1985; Lu et al., 1986); nanosorting based on fluorophore expression; affinity chromatography; cytotoxic agents joined to a monoclonal antibody or used in conjunction with a monoclonal antibody, e.g., complement and cytotoxins; “panning” with antibody attached to a solid matrix (Broxmeyer et al., 1984); selective agglutination using a lectin such as soybean (Reisner et al., 1980); immunomagnetic bead-based sorting or combinations of these techniques, etc. These techniques can also be used to assay for successful engraftment or manipulation of hematopoietic cells in vivo, for example for gene transfer, genetic editing or cell population expansion.
In particular embodiments, it is important to remove contaminating cell populations that would interfere with isolation of the CD34+/CD45RA−/CD90+ cell population, in particular red blood cells. Removing includes both biochemical and mechanical methods to remove the undesired cell populations. Examples include lysis of red blood cells using detergents, hetastarch, hetastarch with centrifugation, cell washing, cell washing with density gradient, Ficoll-hypaque, Sepx, Optipress, Filters, and other protocols that have been used both in the manufacture of HSC cell and/or gene therapies for research and therapeutic purposes.
In particular embodiments, a HSC sample (for example, a fresh cord blood unit) can be processed to select/enrich for CD34+/CD45RA−/CD90+ (both human and NHP), CD34+/CD45RA−/CD90+/CD133+ (human), or CD34+/CD45RA−/CD90+/CD117+ cells (both human and NHP) using appropriate antibodies directly or indirectly conjugated to magnetic particles in connection with a magnetic cell separator, for example, the CliniMACS® Cell Separation System (Miltenyi Biotec, Bergisch Gladbach, Germany). U.S. Pat. No. 5,877,299 describes exemplary hematopoietic antigens that can be used to isolate, collect, and enrich HSC cells from samples.
In particular embodiments, cell populations can be isolated and/or analyzed based on light scattering properties of the cells based on side scatter channel (SSC) brightness and forward scatter channel (FSC) brightness. Side scatter refers to the amount of light scattered orthogonally (90° from the direction of the laser source), as measured by flow cytometry. Forward scatter refers to the amount of light scattered generally less than 90° from the direction of the light source. Generally, as cell granularity increases, the side scatter increases and as cell diameter increases, the forward scatter increases.
Side scatter and forward scatter are measured as intensity of light. Those skilled in the art recognize that the amount of side scatter can be differentiated with user-defined settings. In particular embodiments, low (lo) side scatter refers to less than 50% intensity, less than 40% intensity, less than 30% intensity, or even less intensity, in the side scatter channel of the flow cytometer. Conversely high (hi) side scatter cells are the reciprocal population of cells that are not low side scatter. Forward scatter is defined in the same manner as side scatter but the light is collected in forward scatter channel. Thus, particular embodiments include selection of cell populations based on precise combinations of cell surface markers (CD markers) and the associated light scattering properties of the cells.
The cell populations disclosed herein rely on positive expression of particular CD markers and the negative expression of other CD markers. As is understood by one of ordinary skill in the art of flow cytometry, “hi”, “int”, “lo”, “+” and “−” refer to the intensity of a signal relative to negative or other populations. See, for example,
Novel gating strategies disclosed herein are shown in, for example,
Once HSCs have been collected and isolated, HSC expansion can be performed. Expansion can occur in the presence of one or more growth factors, such as: angiopoietin-like proteins (Angptls, e.g., Angptl2, Angptl3, Angptl7, Angpt15, and Mfap4); erythropoietin; fibroblast growth factor-1 (FGF-1); FLT3-ligand (FLT3-L); granulocyte colony stimulating factor (G-CSF); granulocyte-macrophage colony stimulating factor (GM-CSF); insulin growth factor-2 (IFG-2); interleukin-3 (IL-3); interleukin-6 (IL-6); interleukin-7 (IL-7); interleukin-11 (IL-11); stem cell factor (SCF; also known as the c-kit ligand or mast cell growth factor); thrombopoietin (TPO); and analogs thereof (wherein the analogs include any structural variants of the growth factors having the biological activity of the naturally occurring growth factor; see, e.g., WO 2007/1145227 and U.S. Patent Publication No. 2010/0183564). For clarity, growth factor agents can also be used as mobilizing agents. Particular embodiments utilize expansion in stem cell supportive media (e.g. StemSpan) supplemented with either SCF, TPO, and FLT3-L or SCF and IL-3, or other combinations of growth factors.
In particular embodiments, the type, amount and/or concentration of growth factors suitable for expanding HSC is the amount or concentration effective to promote proliferation. HSC populations are preferably expanded until a sufficient number of cells are obtained to provide for at least one infusion into a human subject, typically around 104 cells/kg to 109 cells/kg.
The amount or concentration of growth factors suitable for expanding HSC depends on the activity of the growth factor preparation, and the species correspondence between the growth factors and HSC, etc. Generally, when the growth factor(s) and HSC are of the same species, the total amount of growth factor in the culture medium ranges from 1 ng/ml to 5 μg/ml, from 5 ng/ml to 1 μg/ml, or from 5 ng/ml to 250 ng/ml. In additional embodiments, the amount of growth factors can be in the range of 5-1000 or 50-100 ng/ml.
In particular embodiments, growth factors are present in an expansion culture condition at the following concentrations: 25-300 ng/ml SCF, 25-300 ng/ml FLT3-L, 25-100 ng/ml TPO, 25-100 ng/ml IL-6 and 10 ng/ml IL-3. In more specific embodiments, 50, 100, or 200 ng/ml SCF; 50, 100, or 200 ng/ml of FLT3-L; 50 or 100 ng/ml TPO; 50 or 100 ng/ml IL-6; and 10 ng/ml IL-3 can be used.
HSC can be expanded in a tissue culture dish onto which an extracellular matrix protein such as fibronectin (FN), or a fragment thereof (e.g., CH-296 (Dao et. al., 1998, Blood 92(12):4612-21)) or RetroNectin® (a recombinant human fibronectin fragment; (Clontech Laboratories, Inc., Madison, Wis.) is bound.
Notch agonists can be particularly useful for expanding HSC. In particular embodiments, HSC can be expanded by exposing the HSC to an immobilized Notch agonist, and 50 ng/ml or 100 ng/ml SCF; to an immobilized Notch agonist, and 50 ng/ml or 100 ng/ml of each of FLT3-L, IL-6, TPO, and SCF; or an immobilized Notch agonist, and 50 ng/ml or 100 ng/ml of each of FLT3-L, IL-6, TPO, and SCF, and 10 ng/ml of IL-11 or IL-3.
Additional methods to expand and/or maintain HSC in culture can utilize one or more of a commercially available base media such as StemSpan SFEM or ACF media (both from Stem Cell Technologies) or XVivo media types (Lonza) supplemented with one or more of: Cyto/chemokines (e.g., G-CSF, SCF, TPO, FLT3-L, IL-3, IL-6); small molecules such as aryl-hydrocarbon receptor antagonists (e.g., StemRegenin1 (e.g., Phenol, 4-[2-[[2-benzo[b]thien-3-yl-9-(1-methylethyl)-9H-purin-6-yl]amino]ethyl]); GNF351 (e.g., N-(2-(3H-Indol-3-yl)ethyl)-9-isopropyl-2-(5-methyl-3-pyridyl)-7H-purin-6-amine, N-(2-(1H-Indol-3-yl)ethyl)-9-isopropyl-2-(5-methylpyridin-3-yl)-9H-purin-6-amine); CH223191 (e.g., 1-Methyl-N-[2-methyl-4-[2-(2-methylphenyl)diazenyl]phenyl-1H-pyrazole-5-carboxamide), pyrimidoindole derivatives (e.g., UM171 (e.g., (1r,4r)-N1-(2-benzyl-7-(2-methyl-2H-tetrazol-5-yl)-9H-pyrimido[4,5-b]indol-4-yl)cyclohexane-1,4-diamine); UM729 (Methyl 4-((3-(piperidin-1-yl)propyl)amino)-9H-pyrimido[4,5-b]indole-7-carboxylate); UM118428 (e.g., Tranylcypromine HCl, (trans-2-Phenylcyclopropylamine hydrochloride)), and glucocorticoid receptor antagonists (e.g., mifepristone (e.g., RU-486), RU-43044, Miconazole, 11-oxa cortisol, 11-oxa prednisolone, Dexamethasone mesylate). Additional agents which could be utilized include protamine sulfate, rapamycin, polybrene, fibronectin fragment, prostaglandins or nonsteroidal anti-inflammatory drugs (e.g., celecoxib, diclofenac, diflunisal, etodolac, ibuprofen, indomethacin, ketoprofen, nabumetone, naproxen, oxaprozin, piroxicam, salsalate, sulindac, tolmetin). Endothelial cell co-culture may also be used.
As is understood by one of ordinary skill in the art, the preceding discussion regarding the processing and development of HSC populations can be applied to process and develop other cell populations including: human MPP (CD34+/CD45RA−/CD90−/CD133+); NHP MPP (CD34+/CD45RA−/CD90−/CD117−); NHP LMP (CD34+/CD45RA+/CD90−/CD117−); NHP EMP (CD34+/CD45RA−/CD90−/CD117−); and NHP MMP (CD34+/CD45RA−/CD90−/CD117+/CD123+) following appropriate manipulation of the protocol for the cell population of interest.
Reference to CD34, CD45RA, CD90, CD117, CD123, and CD133 are understood by those of ordinary skill in the art (see, for example,
In particular embodiments, disclosed cell populations can provide short- and long-term engraftment for a therapeutic purpose, for example, in the context of cord blood transplants, HSC transplants typically are used after radio-ablation of a patient, and other uses such as those described in Gratwohl et al., 2010.
In particular embodiments, disclosed cell populations can undergo genetic modification for the desired research or therapeutic purpose. “Genetic modification or gene-modifying” means gene disruption, gene editing, gene transfer and any combination thereof. In particular embodiments, gene modification or gene-modifying by gene transfer can be accomplished using any number of DNA or RNA viral vector based or non-viral vector based gene transfer technologies. Examples of viral-mediated gene transfer include lentiviral vectors, foamy viral vectors, adenoviral vectors, adeno-associated viral vectors, alpharetroviral vectors or gammaretroviral vectors; non-viral methods include transposon-mediated, plasmid DNA, nanoparticle delivery, or mRNA delivery using transfection, electroporation or nucleofection. Examples of gene editing technologies include specific nucleases, or non-nuclease-based methods. Examples of nuclease-based methods include Zinc fingers (ZFNs), tal effector nucleases (TALENs), meganucleases or meganuclease-TALEN fusions (MegaTALEs), or clustered regularly interspaced short palindromic repeats (CRISPR) delivered with a Cas9 nuclease. Examples of non-nuclease-mediated gene editing include chimeric transcription factors, chimeric chromatin modifiers, forced DNA looping or biodegradable nanoparticles. The phenotype of interest could be used to qualitatively and quantitatively assess the success of manipulations such as gene transfer or genetic editing, expansion or maintenance. For example, there are a number of molecules which are proposed to expand or maintain populations of hematopoietic cells such as StemRegennin1 (SR1), UM171, UM729, LY2228820, Notch Ligands, homeobox proteins, cytokines and chemokines. Measurement of this cell population before and after manipulation could be used as a measure of manipulation success. Aspects of particular of these options are now described in more detail.
Lentiviral vectors. “Lentivirus” refers to a genus of retroviruses that are capable of infecting dividing and non-dividing cells and typically produce high viral titers. Lentiviral vectors have been employed in gene therapy for a number of diseases. For example, hematopoietic gene therapies using lentiviral vectors or gamma retroviral vectors have been used for x-linked adrenoleukodystrophy and beta thalassaemia. See, e.g., Kohn et al., 2010; Cartier et al., 2012; and Cavazzana-Calvo et al., 2010. Several examples of lentiviruses include HIV (human immunodeficiency virus: including HIV type 1, and HIV type 2); equine infectious anemia virus; feline immunodeficiency virus (FIV); bovine immune deficiency virus (BIV); and simian immunodeficiency virus (SIV).
Foamy viruses (FVes) are the largest retroviruses known today and are widespread among different mammals, including all non-human primate species, however are absent in humans. This complete apathogenicity qualifies FV vectors as ideal gene transfer vehicles for genetic therapies in humans and clearly distinguishes FV vectors as gene delivery system from HIV-derived and also gammaretrovirus-derived vectors.
FV vectors are suitable for gene therapy applications because they can (1) accommodate large transgenes (>9 kb), (2) transduce slowly dividing cells efficiently, and (3) integrate as a provirus into the genome of target cells, thus enabling stable long-term expression of the transgene(s). FV vectors do need cell division for the pre-integration complex to enter the nucleus, however the complex is stable for at least 30 days and still infective. The intracellular half-life of the FV pre-integration complex is comparable to the one of lentiviruses and significantly higher than for gammaretroviruses, therefore FV are also—similar to LV vectors—able to transduce rarely dividing cells. FV vectors are natural self-inactivating vectors and characterized by the fact that they seem to have hardly any potential to activate neighboring genes. In addition, FV vectors can enter any cells known (although the receptor is not identified yet) and infectious vector particles can be concentrated 100-fold without loss of infectivity due to a stable envelope protein. FV vectors achieve high transduction efficiency in pluripotent HSC and have been used in animal models to correct monogenetic diseases such as leukocyte adhesion deficiency (LAD) in dogs and Fanconi anemia in mice. FV vectors are also used in preclinical studies of β-thalassemia.
Additional examples of viral vectors include those derived from adenoviruses (e.g., adenovirus 5 (Ad5), adenovirus 35 (Ad35), adenovirus 11 (Ad11), adenovirus 26 (Ad26), adenovirus 48 (Ad48) or adenovirus 50 (Ad50)), adeno-associated virus (AAV; see, e.g., U.S. Pat. No. 5,604,090; Kay et al., 2000; Nakai et al., z1998), alphaviruses, cytomegaloviruses (CMV), flaviviruses, herpes viruses (e.g., herpes simplex), influenza viruses, papilloma viruses (e.g., human and bovine papilloma virus; see, e.g., U.S. Pat. No. 5,719,054), poxviruses, vaccinia viruses, etc. See Kozarsky and Wilson, 1993; Rosenfeld, et al., 1991; Rosenfeld, et al., 1992; Mastrangeli, et al., 1993; Walsh, et al., 1993; and Lundstrom, 1999. Examples include modified vaccinia Ankara (MVA) and NYVAC, or strains derived therefrom. Other examples include avipox vectors, such as a fowlpox vectors (e.g., FP9) or canarypox vectors (e.g., ALVAC and strains derived therefrom).
Other methods of gene delivery include use of artificial chromosome vectors such as mammalian artificial chromosomes (Vos, 1998) and yeast artificial chromosomes (YAC). YAC are typically used when the inserted nucleic acids are too large for more conventional vectors (e.g., greater than 12 kb).
Vectors and other methods to deliver nucleic acids can include regulatory sequences to control the expression of the nucleic acid molecules. These regulatory sequences can be eukaryotic or prokaryotic in nature. In particular embodiments, the regulatory sequence can be a tissue specific promoter such that the expression of the one or more therapeutic proteins will be substantially greater in the target tissue type compared to other types of tissue. In particular embodiments, the regulatory sequence can result in the constitutive expression of the one or more therapeutic proteins upon entry of the vector into the cell. Alternatively, the regulatory sequences can include inducible sequences. Inducible regulatory sequences are well known to those skilled in the art and are those sequences that require the presence of an additional inducing factor to result in expression of the one or more therapeutic proteins. Examples of suitable regulatory sequences include binding sites corresponding to tissue-specific transcription factors based on endogenous nuclear proteins, sequences that direct expression in a specific cell type, the lac operator, the tetracycline operator and the steroid hormone operator. Any inducible regulatory sequence known to those of skill in the art may be used.
In particular embodiments, the nucleic acid is stably integrated into the genome of a cell. In particular embodiments, the nucleic acid is stably maintained in a cell as a separate, episomal segment.
In particular embodiments, the efficiency of integration, the size of the DNA sequence that can be integrated, and the number of copies of a DNA sequence that can be integrated into a genome can be improved by using transposons. Transposons or transposable elements include a short nucleic acid sequence with terminal repeat sequences upstream and downstream. Active transposons can encode enzymes that facilitate the excision and insertion of nucleic acid into a target DNA sequence.
A number of transposable elements have been described in the art that facilitate insertion of nucleic acids into the genome of vertebrates, including humans. Examples include sleeping beauty (e.g., derived from the genome of salmonid fish); piggyback (e.g., derived from lepidopteran cells and/or the Myotis lucifugus); mariner (e.g., derived from Drosophila); frog prince (e.g., derived from Rana pipiens); Tol2 (e.g., derived from medaka fish); TcBuster (e.g., derived from the red flour beetle Tribolium castaneum) and spinON.
Additional Gene Editing Agents. Gene editing agents can modify or affect particular sequences of a cell's endogenous genome. In particular embodiments, the modification includes removal or disruption of an endogenous gene such that the endogenous gene's encoded protein is no longer expressed, expressed to a reduced degree, expressed as an incomplete protein, an unstable protein, an incorrectly folded protein and/or a nonfunctional protein. In particular embodiments, the effect is reduced expression of a protein through an interfering RNA-type mechanism. Thus, gene editing agents are useful for genome editing, for example gene disruption, gene editing by homologous recombination, and gene therapy to insert therapeutic genes at the appropriate chromosomal target sites with a human genome.
Particular gene editing agents include transcription activator-like effector nucleases (TALENs). TALENs refer to fusion proteins including a transcription activator-like effector (TALE) DNA binding protein and a DNA cleavage domain. TALENs are used to edit genes and genomes by inducing double strand breaks (DSBs) in the DNA, which induce repair mechanisms in cells. Generally, two TALENs must bind and flank each side of the target DNA site for the DNA cleavage domain to dimerize and induce a DSB. The DSB is repaired in the cell by non-homologous end-joining (NHEJ) or by homologous recombination (HR) with an exogenous double-stranded donor DNA fragment.
As indicated, TALENs have been engineered to bind a target sequence of, for example, an endogenous genome, and cut DNA at the location of the target sequence. The TALEs of TALENs are DNA binding proteins secreted by Xanthomonas bacteria. The DNA binding domain of TALEs include a highly conserved 33 or 34 amino acid repeat, with divergent residues at the 12th and 13th positions of each repeat. These two positions, referred to as the Repeat Variable Diresidue (RVD), show a strong correlation with specific nucleotide recognition. Accordingly, targeting specificity can be improved by changing the amino acids in the RVD and incorporating nonconventional RVD amino acids.
Examples of DNA cleavage domains that can be used in TALEN fusions are wild-type and variant FokI endonucleases. The FokI domain functions as a dimer requiring two constructs with unique DNA binding domains for sites on the target sequence. The FokI cleavage domain cleaves within a five or six base pair spacer sequence separating the two inverted half-sites.
Particular embodiments utilize MegaTALs as gene editing agents. MegaTALs have a single chain rare-cleaving nuclease structure in which a TALE is fused with the DNA cleavage domain of a meganuclease. Meganucleases, also known as homing endonucleases, are single peptide chains that have both DNA recognition and nuclease function in the same domain. In contrast to the TALEN, the megaTAL only requires the delivery of a single peptide chain for functional activity.
Particular embodiments utilize zinc finger nucleases (ZFNs) as gene editing agents. ZFNs are a class of site-specific nucleases engineered to bind and cleave DNA at specific positions. ZFNs are used to introduce DSBs at a specific site in a DNA sequence which enables the ZFNs to target unique sequences within a genome in a variety of different cells. Moreover, subsequent to double-stranded breakage, homologous recombination or non-homologous end joining takes place to repair the DSB, thus enabling genome editing.
ZFNs are synthesized by fusing a zinc finger DNA-binding domain to a DNA cleavage domain. The DNA-binding domain includes three to six zinc finger proteins which are transcription factors. The DNA cleavage domain includes the catalytic domain of, for example, FokI endonuclease.
Particular embodiments utilize CRISPR-Cas systems as gene editing agents. Guide RNA can be used, for example, with gene-editing agents such as CRISPR-Cas systems. CRISPR-Cas systems include CRISPR repeats and a set of CRISPR-associated genes (Cas).
The CRISPR repeats (clustered regularly interspaced short palindromic repeats) include a cluster of short direct repeats separated by spacers of short variable sequences of similar size as the repeats. The repeats range in size from 24 to 48 base pairs and have some dyad symmetry which implies the formation of a secondary structure, such as a hairpin, although the repeats are not truly palindromic. The spacers, separating the repeats, match exactly the sequences from prokaryotic viruses, plasmids, and transposons. The Cas genes encode nucleases, helicases, RNA-binding proteins, and a polymerase that unwind and cut DNA. Cas1, Cas2, and Cas9 are examples of Cas genes.
The source of CRISPR spacers indicate that CRISPR-Cas systems play a role in adaptive immunity in bacteria. There are at least three types of CRISPR-Cas immune system reactions, and Cas1 and Cas2 genes are involved in spacer acquisition in all three. Spacer acquisition, involving the capture and insertion of invading viral DNA into a CRISPR locus occurs in the first stage of adaptive immunity. More particularly, spacer acquisition begins with Cas1 and Cas2 recognizing invading DNA and cleaving a protospacer, which is ligated to the direct repeat adjacent to a leader sequence. Subsequently, single strand extension repairs take place and the direct repeat is duplicated.
The next stage of CRISPR-related adaptive immunity involves CRISPR RNA (crRNA) biogenesis, which occurs differently in each type of CRISPR-Cas system. In general, during this stage, the CRISPR transcript is cleaved by Cas genes to produce crRNAs. In the type I system, Cas6e/Cas6f cleaves the transcript. The type II system employs a transactivating (tracr) RNA to form a dsRNA, which is cleaved by Cas9 and RNase III. The type III system uses a Cas6 homolog for cleavage.
In the final stage of CRISPR-related adaptive immunity, processed crRNAs associate with Cas proteins to form interference complexes. In type I and type II systems, the Cas proteins interact with protospacer adjacent motifs (PAMs), which are short 3-5 bp DNA sequences, for degradation of invading DNA, while the type III systems do not require interaction with a PAM for degradation. In the type III-B system, the crRNA basepairs with the mRNA, instead of the targeted DNA, for degradation.
CRISPR-Cas systems thus function as an RNAi-like immune system in prokaryotes. The CRISPR-Cas technology has been exploited to inactivate genes in human cell lines and cells. As an example, the CRISPR-Cas9 system, which is based on the type II system, has been used as an agent for genome editing.
The type II system requires three components: Cas9, crRNA, and tracrRNA. The system can be simplified by combining tracrRNA and crRNA into a single synthetic single guide RNA (sgRNA).
At least three different Cas9 nucleases have been developed for genome editing. The first is the wild type Cas9 which introduces DSBs at a specific DNA site, resulting in the activation of DSB repair machinery. DSBs can be repaired by the NHEJ pathway or by homology-directed repair (HDR) pathway. The second is a mutant Cas9, known as the Cas9D10A, with only nickase activity, which means that it only cleaves one DNA strand and does not activate NHEJ. Thus, the DNA repairs proceed via the HDR pathway only. The third is a nuclease-deficient Cas9 (dCas9) which does not have cleavage activity but is able to bind DNA. Therefore, dCas9 is able to target specific sequences of a genome without cleavage. By fusing dCas9 with various effector domains, dCas9 can be used either as a gene silencing or activation tool. In certain embodiments, the method comprises contact the HSC with a nucleic acid encoding a donor template for homology directed repair. For example, the donor template for HDR comprises homology arms to the target sequence, and a transgene to be inserted into the genome of the cell. In some embodiments, the transgene or transgenes to be introduced into the genome, wherein the transgene restores native function of a monogenetic disease, provides insertion of an in vivo selection cassette, render cells resistant to pathogen infections, such as CCR5, and/or contain safety switch technology to destroy the cell in the event of an adverse clinical event. In particular embodiments, the in vivo selection cassettes include knockdown of HPRT with 6TG resistance (Choudhary et al., 2013). In particular embodiments, the in vivo selection cassettes relies on the use of the methylguanine methyltransferase (MGMT) P140K mutation that is resistance to low dose chemotherapy of 06-benzylguanine and telozolomide (Gori et al., 2012).
Therapeutic Uses of Genetically Modified Cell Populations. As one example, a gene can be selected to provide a therapeutically effective response against a condition that, in particular embodiments, is inherited. In particular embodiments, the condition can be Grave's Disease, rheumatoid arthritis, pernicious anemia, Multiple Sclerosis (MS), inflammatory bowel disease, systemic lupus erythematosus (SLE), adenosine deaminase deficiency (ADA-SCID) or severe combined immunodeficiency disease (SCID) stemming from deficiency in gamma chain (X-linked SCID), JAK 3 kinase deficiency, purine nucleoside phosphorylase deficiency, adenosine deaminase (ADA) deficiency, MHC Class II deficiency or recombinase activating gene (RAG) deficiency, Wiskott-Aldrich syndrome (WAS), chronic granulomatous disease (CGD), Fanconi anemia (FA), Battens disease, adrenoleukodystrophy (ALD) or metachromatic leukodystrophy (MLD), muscular dystrophy, pulmonary alveolar proteinosis (PAP), pyruvate kinase deficiency, Shwachmann-Diamond-Blackfan anemia, dyskeratosis congenita, xeroderma pigmentosa, cystic fibrosis, Parkinson's disease, Alzheimer's disease, or amyotrophic lateral sclerosis (Lou Gehrig's disease). In particular embodiments, depending on the condition, the therapeutic gene may be a gene that encodes a protein and/or a gene whose function has been interrupted. Exemplary therapeutic gene and gene products include: soluble CD40; CTLA; Fas L; antibodies to CD4, CD5, CD7, CD52, etc.; antibodies to 11_1, 1 L2, 1L6; an antibody to TCR specifically present on autoreactive T cells; IL4; IL10; IL12; IL13; ID Ra, sIL1RI, sIL1RII; sTNFRI; sTNFRII; antibodies to TNF; P53, PTPN22, and DRB1*1501/DQB1*0602; globin family genes; WAS; phox; FANC family genes; dystrophin; pyruvate kinase; CLN3; ABCD1; arylsulfatase A; SFTPB; SFTPC; NLX2.1; ABCA3; GATA1; ribosomal protein genes; TERT; TERC; DKC1; TINF2; CFTR; LRRK2; PARK2; PARK7; PINK1; SNCA; PSEN1; PSEN2; APP; SOD1; TDP43; FUS; ubiquilin 2; and/or C9ORF72. Therapeutically effective amounts may provide function to immune and other blood cells and/or microglial cells or may alternatively—depending on the treated condition—inhibit lymphocyte activation, induce apoptosis in lymphocytes, eliminate various subsets of lymphocytes, inhibit T cell activation, eliminate or inhibit autoreactive T cells, inhibit Th-2 or Th-1 lymphocyte activity, antagonize IL1 or TNF, reduce inflammation, induce selective tolerance to an inciting agent, reduce or eliminate an immune-mediated condition; and/or reduce or eliminate a symptom of the immune-mediated condition. Therapeutic effective amounts may also provide functional DNA repair mechanisms; surface protein expression; telomere maintenance; lysosomal function; breakdown of lipids or other proteins such as amyloids; permit ribosomal function; and/or permit development of mature blood cell lineages which would otherwise not develop such as macrophages other white blood cell types.
As another example, a gene can be selected to provide a therapeutically effective response against diseases related to red blood cells and clotting. In particular embodiments, the disease is a hemoglobinopathy like thalassemia, or a sickle cell disease/trait. The therapeutic gene may be, for example, a gene that induces or increases production of hemoglobin; induces or increases production of beta-globin, or alpha-globin; or increases the availability of oxygen to cells in the body. The therapeutic gene may be, for example, HBB or CYB5R3. Exemplary effective treatments may, for example, increase blood cell counts, improve blood cell function, or increase oxygenation of cells in patients. In another particular embodiment, the disease is hemophilia. The therapeutic gene may be, for example, a gene that increases the production of coagulation/clotting factor VIII or coagulation/clotting factor IX, causes the production of normal versions of coagulation factor VIII or coagulation factor IX, a gene that reduces the production of antibodies to coagulation/clotting factor VIII or coagulation/clotting factor IX, or a gene that causes the proper formation of blood clots. Exemplary therapeutic genes include F8 and F9. Exemplary effective treatments may, for example, increase or induce the production of coagulation/clotting factors VIII and IX; improve the functioning of coagulation/clotting factors VIII and IX, or reduce clotting time in subjects.
Other uses with supporting detail are found in PCT/US2016/014378.
In these embodiments, cell populations (e.g., HSC populations, MPP populations) can be formulated into cell-based compositions for administration to a subject. A cell-based composition refers to expanded cells prepared with a pharmaceutically acceptable carrier for administration to a subject. In particular embodiments, cell-based compositions are administered to a subject in need thereof as soon as is reasonably possible following the completion of expansion and formulation for administration.
Exemplary carriers include saline, buffered saline, physiological saline, water, Hanks' solution, Ringer's solution, Nonnosol-R (Abbott Labs), Plasma-Lyte A® (Baxter Laboratories, Inc., Morton Grove, Ill.), glycerol, ethanol, and combinations thereof.
In particular embodiments, carriers can be supplemented with human serum albumin (HSA) or other human serum components or fetal bovine serum or other species serum components. In particular embodiments, a carrier for infusion includes buffered saline with 5% HSA or dextrose. Additional isotonic agents include polyhydric sugar alcohols including trihydric or higher sugar alcohols, such as glycerin, erythritol, arabitol, xylitol, sorbitol, or mannitol.
Carriers can include buffering agents, such as citrate buffers, succinate buffers, tartrate buffers, fumarate buffers, gluconate buffers, oxalate buffers, lactate buffers, acetate buffers, phosphate buffers, histidine buffers, and/or trimethylamine salts.
Stabilizers refer to a broad category of excipients which can range in function from a bulking agent to an additive which helps to prevent cell adherence to container walls. Typical stabilizers can include polyhydric sugar alcohols; amino acids, such as arginine, lysine, glycine, glutamine, asparagine, histidine, alanine, ornithine, L-leucine, 2-phenylalanine, glutamic acid, and threonine; organic sugars or sugar alcohols, such as lactose, trehalose, stachyose, mannitol, sorbitol, xylitol, ribitol, myoinisitol, galactitol, glycerol, and cyclitols, such as inositol; PEG; amino acid polymers; sulfur-containing reducing agents, such as urea, glutathione, thioctic acid, sodium thioglycolate, thioglycerol, alpha-monothioglycerol, and sodium thiosulfate; low molecular weight polypeptides (i.e., <10 residues); proteins such as HSA, bovine serum albumin, gelatin or immunoglobulins; hydrophilic polymers such as polyvinylpyrrolidone; monosaccharides such as xylose, mannose, fructose and glucose; disaccharides such as lactose, maltose and sucrose; trisaccharides such as raffinose, and polysaccharides such as dextran.
Where necessary or beneficial, cell-based compositions can include a local anesthetic such as lidocaine to ease pain at a site of injection.
Therapeutically effective amounts of cells within cell-based compositions can be greater than 102 cells, greater than 103 cells, greater than 104 cells, greater than 105 cells, greater than 106 cells, greater than 107 cells, greater than 108 cells, greater than 109 cells, greater than 1010 cells, or greater than 1011.
In cell-based compositions disclosed herein, cells are generally in a volume of a liter or less, 500 mls or less, 250 mls or less or 100 mls or less. Hence the density of administered cells is typically greater than 104 cells/ml, 107 cells/ml or 108 cells/ml.
The cell-based compositions disclosed herein can be prepared for administration by, for example, injection, infusion, perfusion, or lavage.
In particular embodiments, it can be necessary or beneficial to cryopreserve a cell and/or cell-based composition. The terms “frozen/freezing” and “cryopreserved/cryopreserving” can be used interchangeably. Freezing includes freeze drying. As is understood by one of ordinary skill in the art, the freezing of cells can be destructive (see Mazur, P., 1977, Cryobiology 14:251-272) but there are numerous procedures available to prevent such damage. For example, damage can be avoided by (a) use of a cryoprotective agent, (b) control of the freezing rate, and/or (c) storage at a temperature sufficiently low to minimize degradative reactions. Exemplary cryoprotective agents include dimethyl sulfoxide (DMSO) (Lovelock and Bishop, 1959, Nature 183:1394-1395; Ashwood-Smith, 1961, Nature 190:1204-1205), glycerol, polyvinylpyrrolidine (Rinfret, 1960, Ann. N.Y. Acad. Sci. 85:576), polyethylene glycol (Sloviter and Ravdin, 1962, Nature 196:548), albumin, dextran, sucrose, ethylene glycol, i-erythritol, D-ribitol, D-mannitol (Rowe et al., 1962), D-sorbitol, i-inositol, D-lactose, choline chloride (Bender et al., 1960), amino acids (Phan The Tran and Bender, 1960), methanol, acetamide, glycerol monoacetate (Lovelock, 1954), and inorganic salts (Phan The Tran and Bender, 1960; Phan The Tran and Bender, 1961). In particular embodiments, DMSO can be used. Addition of plasma (e.g., to a concentration of 20-25%) can augment the protective effects of DMSO. After addition of DMSO, cells can be kept at 0° C. until freezing, because DMSO concentrations of 1% can be toxic at temperatures above 4° C.
In the cryopreservation of cells, slow controlled cooling rates can be critical and different cryoprotective agents (Rapatz et al., 1968) and different cell types have different optimal cooling rates (see e.g., Rowe and Rinfret, 1962; Rowe, 1968; Lewis, et al., 1967; and Mazur, 1970 for effects of cooling velocity on survival of stem cells and on their transplantation potential). The heat of fusion phase where water turns to ice should be minimal. The cooling procedure can be carried out by use of, e.g., a programmable freezing device or a methanol bath procedure. Programmable freezing apparatuses allow determination of optimal cooling rates and facilitate standard reproducible cooling.
In particular embodiments, DMSO-treated cells can be pre-cooled on ice and transferred to a tray containing chilled methanol which is placed, in turn, in a mechanical refrigerator (e.g., Harris or Revco) at −80° C. Thermocouple measurements of the methanol bath and the samples indicate a cooling rate of 1° to 3° C./minute can be preferred. After at least two hours, the specimens can have reached a temperature of −80° C. and can be placed directly into liquid nitrogen (−196° C.).
After thorough freezing, the cells can be rapidly transferred to a long-term cryogenic storage vessel. In a preferred embodiment, samples can be cryogenically stored in liquid nitrogen (−196° C.) or vapor (−1° C.). Such storage is facilitated by the availability of highly efficient liquid nitrogen refrigerators.
Further considerations and procedures for the manipulation, cryopreservation, and long term storage of cells, can be found in the following exemplary references: U.S. Pat. Nos. 4,199,022; 3,753,357; and 4,559,298; Gorin, 1986; Bone-Marrow Conservation, Culture and Transplantation, Proceedings of a Panel, Moscow, Jul. 22-26, 1968, International Atomic Energy Agency, Vienna, pp. 107-186; Livesey and Linner, 1987; Linner et al., 1986; Simione, 1992).
Following cryopreservation, frozen cells can be thawed for use in accordance with methods known to those of ordinary skill in the art. Frozen cells are preferably thawed quickly and chilled immediately upon thawing. In particular embodiments, the vial containing the frozen cells can be immersed up to its neck in a warm water bath; gentle rotation will ensure mixing of the cell suspension as it thaws and increase heat transfer from the warm water to the internal ice mass. As soon as the ice has completely melted, the vial can be immediately placed on ice.
In particular embodiments, methods can be used to prevent cellular clumping during thawing. Exemplary methods include: the addition before and/or after freezing of DNase (Spitzer et al., 1980), low molecular weight dextran and citrate, hydroxyethyl starch (Stiff et al., 1983), etc.
As is understood by one of ordinary skill in the art, if a cryoprotective agent that is toxic to humans is used, it should be removed prior to therapeutic use. DMSO has no serious toxicity.
1. A method of creating a stem cell population with predictive engraftment potential that provides multilineage hematopoietic recovery including: obtaining a biological sample including a stem cell source; separating the CD34+ enriched sample based on cell surface expression of markers consisting of CD34+/CD45RA−/CD90−; thereby creating a stem cell population with predictive engraftment potential that provides multilineage hematopoietic recovery.
2. A method of creating a stem cell population with predictive engraftment potential that provides multilineage hematopoietic recovery including: obtaining a stem cell source; removing red blood cells from the biological sample; enriching the biological sample for CD34+ cells to create a CD34+ enriched sample; and separating the CD34+ enriched sample based on cell surface expression of markers consisting of CD34+/CD45RA−/CD90−; thereby creating a stem cell population with predictive engraftment potential that provides multilineage hematopoietic recovery.
3. A method including: isolating a stem cell population that is CD34+/CD45RA−/CD90+; CD34+/CD45RA−/CD90+/CD133+; CD34+/CD45RA−/CD90−/CD133+; CD34+/CD45RA−/CD90+/CD117+; CD34+/CD45RA−/CD90−/CD117+; CD34+/CD45RA+/CD90−/CD117+; CD34+/CD45RA−/CD90−/CD117−; or CD34+/CD45RA−/CD90−/CD117+/CD123+ for use in the development of a clinical treatment wherein the isolating does not utilize CD38 or CD49f.
4. Use of a stem cell population that is CD34+/CD45RA−/CD90+; CD34+/CD45RA−/CD90+/CD133+; CD34+/CD45RA−/CD90−/CD133+; CD34+/CD45RA−/CD90+/CD117+; CD34+/CD45RA−/CD90−/CD117+; CD34+/CD45RA+/CD90−/CD117+; CD34+/CD45RA−/CD90−/CD117−; or CD34+/CD45RA−/CD90−/CD117+/CD123+ in the development of a clinical treatment wherein the stem cell population is isolated independently of CD38 and CD49f.
5. A method of analyzing and/or predicting multi-lineage long-term engraftment in the setting of transplantation wherein the method does not utilize CD38 or CD49f including staining cells from a stem cell source for cell surface markers selected from one of the following profiles: CD34+/CD45RA−/CD90+; CD34+/CD45RA−/CD90+/CD133+; CD34+/CD45RA−/CD90−/CD133+; CD34+/CD45RA−/CD90+/CD117+; CD34+/CD45RA−/CD90−/CD117+; CD34+/CD45RA+/CD90−/CD117+; CD34+/CD45RA−/CD90−/CD117−; or CD34+/CD45RA−/CD90−/CD117+/CD123+ analyzing the frequency and absolute cell counts of the selected profile; defining the cell count for cells/kg; and cross-referencing the cell count against a threshold for engraftment success, thereby analyzing and/or predicting multi-lineage long-term engraftment in the setting of transplantation wherein the application does not utilize CD38 or CD49f.
6. A method of analyzing and/or predicting the onset of neutrophil and platelet recovery in the setting of transplantation including staining cells from a stem cell source for cell surface markers selected from one of the following profiles: CD34+/CD45RA−/CD90+; CD34+/CD45RA−/CD90+/CD133+; CD34+/CD45RA−/CD90−/CD133+; CD34+/CD45RA−/CD90+/CD117+; CD34+/CD45RA−/CD90−/CD117+; CD34+/CD45RA+/CD90−/CD117+; CD34+/CD45RA−/CD90−/CD117−; or CD34+/CD45RA−/CD90−/CD117+/CD123+ analyzing the frequency and absolute cell counts of the selected profile; defining the cell count for cells/kg; and cross-referencing the cell count against a threshold for neutrophil and platelet recovery thereby analyzing and/or predicting the onset of neutrophil and platelet recovery in the setting of transplantation wherein the application does not utilize CD38 or CD49f.
7. A method or use of any of embodiments 1-6 wherein the stem cell source includes umbilical cord blood, placental blood, bone marrow, or peripheral blood.
8. A method or use of any of embodiments 1-7 wherein the stem cell source is fresh, frozen, culture-expanded, gene edited or gene modified.
9. A method or use of any of embodiments 1-8 wherein the stem cell source is embryonic stem cell (ESC), pluripotent stem cell (PSC) or induced pluripotent stem cell (iPSC).
10. A method or use of any of embodiments 1-9 wherein enriching includes magnetic-assisted cell sorting (MACS) using an anti-CD34+ antibody.
11. A method or use of any of embodiments 1-10 wherein separating includes flow sorting.
12. A method or use of any of embodiments 1-11 including culturing the stem cell population in a culture media supplemented with either human stem cell factor (SCF), human thrombopoietin (TPO), and human Fms-related tyrosine kinase 3 ligand (FLT-3L) or SCF and human interleukin-3 (IL-3).
13. A method or use of embodiment 12 wherein the SCF, TPO and FLT-3L or the SCF and IL-3 are recombinant SCF, TPO and FLT-3L or recombinant SCF and IL-3.
14. A method or use of any of embodiments 1-13 wherein isolating does not utilize markers other than CD34, CD45RA, CD90, CD117, CD123, and/or CD133.
15. A method or use of any of embodiments 1-13 wherein the isolating does not utilize CD3, CD7, CD10, CD13, CD14, CD33, CD38, CD41, CD56, CD105, CD127, CD135, and/or CD138.
16. A method or use of any of embodiments 1-13 wherein the stem cell population is CD34+/CD45RA−/CD90+; CD34+/CD45RA−/CD90+/CD133+ or CD34+/CD45RA−/CD90+/CD117+.
17. A method or use of any of embodiments 1-13 wherein the stem cell population is CD34+/CD45RA−/CD90+; CD34+/CD45RA−/CD90+/CD133+ or CD34+/CD45RA−/CD90+/CD117+ and has self-renewing capacity, multi-lineage potential, long-term engraftment capability, and predictably correlates with hematopoietic recovery after transplantation or radiation exposure.
18. A method or use of any of embodiments 1-13 wherein the stem cell population predictably correlates with hematopoietic recovery after transplantation or radiation exposure quantitatively or logarithmically.
19. A method or use of any of embodiments 1-18 wherein the predictable correlation includes an R2 score having an absolute value of 0.5 or more, 0.6 or more, 0.7 or more, 0.8 or more, or 0.9 or more.
20. A method or use of embodiment 19 wherein the predictable correlation occurs with a cell dose of at least 122,000 cells/kg when administered to a subject.
21. A stem cell population formed according to a method of any one of embodiments 1, 2, 3, and/or 7-17.
22. A stem cell population of embodiment 21 that is genetically-modified.
23. A stem cell population of embodiment 22 wherein the genetic modification inserts or alters a gene selected from ABCD1, ABCA3, ABLI, ADA, AKT1, APC, APP, ARSA, ARSB, BCL11A, BLC1, BLC6, BRCA1, BRCA2, BRIP1, C9ORF72, C46 or other C peptide, CAR, CAS9, C-CAM, CBFAI, CBL, CCR5, CD4, CD19, CD40, CDA, CFTR, CLN3, C-MYC, CRE, CSCR4, CSFIR, CTLA, CTS-I, CYB5R3, DCC, DHFR, DKC1, DLL1, DMD, EGFR, ERBA, ERBB, EBRB2, ETSI, ETS2, ETV6, F8, F9, FANCA, FANCB, FANCC, FANCD2, FANCE, FANCF, FANCG, FANCI, FANCL, FANCM, FasL, FCC, FGR, FOX, FUS, FUSI, FYN, GALNS, GATA1, GLB1, GNS, GUSB, HBB, HBD, HBE1, HBG1, HBG2, HCR, HGSNAT, HOXB4, HRAS, HYAL1, ICAM-1, iCaspase, IDUA, IDS, JUN, KLF4, KRAS, LCK, LRRK2, LYN, MCC, MDM2, MGMT, MLL, MMACI, MYB, MEN-I, MEN-II, MYC, NAGLU, NANOG, NF-1, NF-2, NKX2.1, NOTCH, OCT4, p16, p21, p27, p53, p57, p73, PALB2, PARK2, PARK7, phox, PINK1, PK, PSEN1, PSEN2, PTPN22, RAD51C, ras, RPL3 through RPL40, RPLP0, RPLP1, RPLP2, RPS2 through RPS30, RPSA, SFTPB, SFTPC, SGSH, SLX4, SNCA, SOD1, SOX2, TERC, TERT, TDP43, TINF2, TK, ubiquilin 2, VHL, WAS and WT-I.
24. A stem cell population of embodiment 22 or 23 wherein the genetic modification includes a non-integrating vector.
25. A stem cell population of any of embodiments 22-24 wherein the genetic modification includes a viral vector.
26. A stem cell population of any of embodiments 22-25 wherein the genetic modification includes a lentiviral vector.
27. A stem cell population of embodiment 26 wherein the lentiviral vector includes a pseudotype envelope glycoprotein and a lentiviral RNA molecule.
28. A stem cell population of embodiment 27 wherein the pseudotype envelope glycoprotein includes vesicular stomatitis virus glycoprotein (VSVG), cocal virus glycoprotein (cocal), the feline endogenous virus glycoprotein (RD114), or modified foamy virus glycoprotein (mFoamy).
29. A stem cell population of embodiment 27 wherein the lentiviral RNA molecule includes a HIV-1-derived, self-inactivating lentivirus backbone.
30. A stem cell population of embodiment 27 wherein the lentiviral RNA molecule includes a HIV-1-derived, self-inactivating lentivirus backbone which is integration deficient.
31. A stem cell population of any of embodiments 22-30 wherein the genetic modification includes a gammaretroviral vector.
32. A stem cell population of embodiment 31 wherein the gammaretroviral vector includes a pseudotype envelope glycoprotein and a gammaretroviral RNA molecule.
33. A stem cell population of embodiment 32 wherein the pseudotype envelope glycoprotein includes gibbon ape leukemia virus glycoprotein (GALV), or the feline endogenous virus envelope (RD114).
34. A stem cell population of embodiment 32 wherein the gammaretroviral RNA molecule includes a self-inactivating gammaretrovirus backbone.
35. A stem cell population of embodiment 32 wherein the gammaretroviral RNA molecule includes a self-inactivating gammaretrovirus backbone which is integration deficient.
36. A stem cell population of any of embodiments 22-35 wherein the genetic modification includes a foamy viral vector.
37. A stem cell population of embodiment 36 wherein the foamy viral vector includes a pseudotype envelope glycoprotein and a foamy viral RNA molecule.
38. A stem cell population of embodiment 37 wherein the pseudotype envelope glycoprotein includes foamy viral envelope protein (Foamy), or modified foamy viral envelope protein (mFoamy).
39. A stem cell population of embodiment 37 wherein the foamy viral RNA molecule includes a self-inactivating foamy virus backbone.
40. A stem cell population of embodiment 37 wherein the foamy viral RNA molecule includes a self-inactivating foamy virus backbone which is integration deficient.
41. A stem cell population of any of embodiments 22-40 wherein the genetic modification includes an alpharetroviral vector.
42. A stem cell population of embodiment 41 wherein the alpharetroviral vector includes a pseudotype envelope glycoprotein and an alpharetroviral RNA molecule.
43. A stem cell population of embodiment 42 wherein the pseudotype envelope glycoprotein includes the vesicular stomatitis virus glycoprotein (VSVG), cocal virus glycoprotein (cocal), the feline endogenous virus glycoprotein (RD114), or modified foamy virus glycoprotein (mFoamy).
44. A stem cell population of embodiment 42 wherein the alpharetroviral RNA molecule includes a self-inactivating alpharetrovirus backbone.
45. A stem cell population of any of embodiments 22-44 wherein the genetic modification includes a lentiviral, gammaretroviral, foamy viral or alpharetorviral vector further including one or more promoter elements, selection cassettes, enhancer elements, insulator elements, regulatory elements, and transcription/translation enhancer elements.
46. A stem cell population of embodiment 45 wherein the transcription/translation enhancer elements include partial woodchuck hepatitis virus post-transcriptional regulatory elements, 2A viral fusion elements or internal ribosomal entry site (IRES) sequences.
47. A stem cell population of any of embodiments 22-46 wherein the genetic modification includes naked DNA, naked mRNA, an adenoviral vector, or an adeno-associated vector, guide RNA, zinc fingers, meganucleases, TALENs, meganuclease-TALEN fusions (megaTALs), and/or genes flanked by regions of homology.
48. A cell-based composition including a stem cell population of any of embodiments 21-47.
49. A method of treating a subject including administering a therapeutically effective amount of a cell-based composition of embodiment 48.
50. A method embodiment 49 wherein the subject is human or a non-human primate.
51. A method of embodiment 49 or 50 wherein the subject is in need of a clinical treatment.
52. A method of embodiment 51 wherein the clinical treatment is directed to alleviating an effect of a condition associated with myelosuppression or myeloablation.
53. A method of embodiment 52 wherein the condition associated with myelosuppression or myeloablation is one or more of exposure to radiation or chemical(s), an immune-mediated condition, an immune deficiency disease, an inherited genetic disorder, a blood disorder, a lysosomal storage disorder, a hyperproliferative disease, a malignant disease, or an infectious disease.
54. A method of embodiment 53 wherein the immune-mediated condition is Grave's Disease, rheumatoid arthritis, pernicious anemia, Multiple Sclerosis (MS), inflammatory bowel disease, systemic lupus erythematosus (SLE), or an immune deficiency disease.
55. A method of embodiment 53 wherein the immune deficiency disease is one or more of severe combined immunodeficiency disease (SCID), adenosine deaminase deficient SCID (ADA-SCID), or Wiskott-Aldrich syndrome (WAS), or chronic granulomatous disease (CGD).
56. A method of embodiment 53 wherein the inherited genetic disorder is chronic granulomatous disease (CGD), Fanconi anemia (FA), Shwachmann-Diamond-Blackfan anemia (DBA), dyskeratosis congenita (DKC), pyruvate kinase deficiency (PKD), cystic fibrosis (CF), pulmonary alveolar proteinosis (PAP), Batten's disease, adrenoleukodystrophy (ALD), metachromatic leukodystrophy (MLD), muscular dystrophy (MD), Parkinson's disease, Alzheimer's disease, or amyotrophic lateral sclerosis (ALS; Lou Gehrig's disease).
57. A method of embodiment 53 wherein the blood disorder is hemoglobinopathy like thalassemia, or sickle cell anemia.
58. A method of embodiment 53 wherein the lysosomal storage disorder is mucopolysaccharidosis (MPS) type I, MPS II, MPS III, MPS IV, MPS V, MPS VI, MPS VII, alpha-mannosidosis, beta-mannosidosis, Tay Sachs, Pompe disease, Gaucher's disease, or Fabry disease.
59. A method of embodiment 53 wherein the hyperproliferative disease is cancer.
60. A method of embodiment 59 wherein the cancer is a malignant cancer.
61. A method of embodiment 53 wherein the infectious disease is caused by infection with a virus.
62. A method of embodiment 61 wherein the virus is one or more of HIV, measles, coronavirus, or aminopeptidase-N, LCMV/lassa fever virus.
63. A method of embodiment 53 wherein the infectious disease is caused by infection with a bacteria, and/or parasites.
64. A method of embodiment 51 wherein the clinical treatment is transplantation.
65. A method of embodiment 64 wherein the transplantation is myeloablative transplantation.
66. A method of embodiment 64 or 65 wherein the transplantation is myeloablative autologous transplantation.
67. A method of any of embodiments 64-66 wherein the transplantation utilizes genotoxic conditioning.
68. A method of any of embodiments 64-66 wherein the transplantation includes a non-genotoxic condition autologous transplantation.
69. A method of embodiment 64 wherein the transplantation is allogeneic.
70. A method of any of embodiments 49-69 wherein the therapeutically effective amount results in multilineage hematopoietic recovery including short-term engraftment and long-term engraftment.
71. A method of embodiment 70 wherein short-term engraftment is evidenced by neutrophil engraftment and platelet engraftment.
72. A method of embodiment 70 or 71 wherein long-term engraftment is evidenced by flow cytometric analysis of genetically-modified white blood cells.
73. A method of any of embodiments 70-72 wherein long-term engraftment is evidenced by flow cytometric analysis of genetically-modified granulocytes, monocytes, B cells, T cells, NK cells, and erythrocytes.
74. A method of providing short-term and long-term engraftment of HSC in a subject in need thereof including administering a stem cell population that is isolated using (i) CD34+/CD45RA−/CD90+; (ii) CD34+/CD45RA−/CD90+/CD133+ or (iii) CD34+/CD45RA−/CD90+/CD117+ wherein the stem cell population was isolated independently of CD38 and CD49f.
NHP Animal Care. Healthy juvenile pigtail macaques (Macaca nemestrina) as well as juvenile rhesus macaques (Macaca mulatta), which served as donors for BM CD34+ cells in these studies under conditions approved by the American Association for the Accreditation of Laboratory Animal Care.
Cell Sources, CD34+ Enrichment and in Vitro Culture. Human GCSF-primed peripheral blood stem cells (PBSCs) CD34+ cells were collected after informed consent according to the Declaration of Helsinki and enriched as previously described (Radtke et al., 2015). Pigtail macaque steady state bone marrow, GCSF/SCF-primed bone marrow and umbilical cord blood, as well as Rhesus macaque steady state bone marrow CD34+ cells were harvested and enriched as previously described (Trobridge et al., 2008). Briefly for enrichment of NHP CD34+ cells, red cells were lysed in ammonium chloride lysis buffer, while white blood cells were incubated for 20 minutes with the 12.8 immunoglobulin M anti-CD34 antibody, then washed and incubated for another 20 minutes with magnetic activated cell sorting anti-immunoglobulin M microbeads (Miltenyi Biotech, Bergisch Gladbach, Germany). For enrichment of human CD34+ cells, microbead conjugated anti-CD34 antibody (Miltenyi Biotech) was used. The cell suspension was run through magnetic columns enriching for CD34+ cell fractions with a purity of 60-80% confirmed by flow cytometry. Enriched CD34+ cells were cultured in StemSpan (Stemcell Technologies, Vancouver, British Columbia, Canada) supplemented with 100 U/ml penicillin streptomycin (Gibco by Life Technologies, Waltham, Mass.) and either SCF (Peprotech, Rocky Hill, N.J.), TPO (Peprotech) and FLT3-L (Miltenyi Biotec), or SCF and IL-3 (Peprotech) (100 ng/ml each).
Flow Cytometry Analysis and FACS. Antibodies used for FACS analysis and sorting of pigtail macaque and rhesus macaque cells are listed in
Colony-forming Cell (CFC) Assay. For CFC assays 1000-1200 sorted cells were seeded into 3.5 ml ColonyGEL 1402 (ReachBio, Seattle, Wash.). Hematopoietic colonies were scored after 12-14 days. Arising colonies were identified as colony forming unit- (CFU-) granulocyte (CFU-G), macrophage (CFU-M), granulocyte-macrophage (CFU-GM) and burst forming unit-erythrocyte (BFU-E). Colonies including erythroid and myeloid cells were scored as CFU-MIX. For secondary CFC assays, all cells or individual colonies were harvested, dissociated, washed, and seeded into 3.5 ml ColonyGel 1402. Hematopoietic colonies were analyzed/quantified after 12-14 days without discrimination of colony-subtypes.
Megakaryocyte Assay. For megakaryocyte differentiation 3,000-5,000 sorted cells were seeded into 2 ml MegaCult (StemCell Technologies) and differentiation performed according to the manufacturer's instructions. Myeloid (granulocytes and/or macrophages/monocytes) as well as megakaryocyte colonies were quantified microscopically after 10-12 days.
T Cell Assay. T cell differentiation potential was tested as previously described (La Motte-Mohs et al., 2005). Sort-purified CD34-subpopulations were co-cultured with murine stromal cells OP9-DL1 expressing the mouse Delta-like 1 gene (Schmitt and Zuniga-Pflucker, 2002) in α-minimal essential medium (a MEM) (Gibco by Life Technologies) supplemented with 20% FBS, 100 U/ml penicillin, 100 U/ml streptomycin, 5 ng/ml FLT3-L, and 5 ng/ml IL-7 (R&D System, Minneapolis, Minn.). Half-media changes were performed on a bi-weekly basis. Obtained cells were stained with antibodies against CD2, CD3, CD4, CD5, CD8, and CD45 and analyzed/quantified by flow cytometry 5 weeks post-seeding.
MS-5 Assay. Lympho-myeloid differentiation potentials were tested in the clonal MS-5 assay as previously described (Doulatov et al., 2010). Single-sorted hematopoietic progenitors were deposited onto stromal MS-5 cells (Itoh et al., 1989) in 96-well plates. Co-cultures were carried out in H5100 medium (StemCell Technologies) supplemented with 100 U/ml penicillin, 100 U/ml streptomycin, 100 ng/ml SCF, 50 ng/ml TPO, 20 ng/ml IL-2 (R&D System) and 10 ng/ml IL-7 for 5 weeks with weekly half-media changes. Cells were harvested by physical dissociation, filtered through a 70-μm filter, and stained with antibodies against CD11b, CD14, CD20, CD34, CD45, and CD56 for analysis by flow cytometry.
RNA Isolation and RNA-Seq. Total RNA was extracted from sort-purified cell populations with the Arcturus PicoPure RNA Isolation Kit (Thermo Fisher Scientific, Waltham, Mass.) according to the manufacturer's protocol. All original RNA-seq data were uploaded to the NCBI database (BioProject Accession codes PRJNA320857 [NHP] and PRJNA320858 [human]). Detailed information on the RNA QC, sequencing, and analysis of RNA-seq data is below in the Supplemental Experimental Procedures sections.
Statistics. Statistical analysis was performed using GraphPad Prism Version 5. All data are given as mean±standard error of the mean (SEM). Significance analyses was performed with the paired Student t test (*: p<0.05; **: p<0.01; ***: p<0.001).
Supplemental Experimental Procedures. RNA quality control: Total RNA integrity was analyzed using an Agilent 2200 TapeStation (Agilent Technologies, Inc., Santa Clara, Calif.) and quantified using a Trinean DropSense96 spectrophotometer (Caliper Life Sciences, Hopkinton, Mass.).
RNA-seq expression analysis: RNA-seq libraries were prepared from total RNA using the TruSeq RNA Sample Prep Kit (Illumina, Inc., San Diego, Calif., USA) and a Sciclone NGSx Workstation (PerkinElmer, Waltham, Mass., USA). Library size distribution was validated using an Agilent 2200 TapeStation (Agilent Technologies, Santa Clara, Calif., USA). Additional library QC, blending of pooled indexed libraries, and cluster optimization was performed using Life Technologies Invitrogen Qubit® 2.0 Fluorometer (Life Technologies-Invitrogen, Carlsbad, Calif., USA). RNA-seq libraries were pooled and clustered onto a flow cell lane. Sequencing was performed using an Illumina HiSeq 2500 in rapid mode employing a paired-end, 50 base read length (PE50) sequencing strategy.
Image analysis and base calling was performed using Illumina's Real Time Analysis v1.18 software, followed by ‘demultiplexing’ of indexed reads and generation of FASTQ files, using Illumina's bcl2fastq Conversion Software v1.8.4.
RNA-seq data analysis: Paired reads were aligned to the human genome assembly (hg38) (Lander et al., 2001) using bwa aln (Li and Durbin, 2009). SAM files were converted to BAM files and subsequently merged using the samtools view and merge options, respectively (Li et al., 2009). The RNA-sequence analysis relies on the Bioconductor packages for R and follows the workflow outlined by Love et al. (2015) (Huber et al., 2015; Love et al., 2015). The gene transfer format (GTF) file (Homo_sapiens.GRCh38.83.gtf) used to define genomic features was obtained from Ensembl (Zerbino et al., 2015) and read into R as a transcription database object using the GenomicFeatures package (Lawrence et al., 2013). The seqlevels, mapSeqlevels, newstyle, and renameSeqlevels functions from the GenomeInfoDb package were used to convert from Ensembl chromosome labels to UCSC labels. Using the GenomicFeatures package, transcripts identified in the transcription database object were organized by genes as a GRangesList object (Lawrence et al., 2013). Reads for each gene were counted using the summarizeOverlaps function from the GenomicAlignments package in “IntersectionNotEmpty” mode (Lawrence et al., 2013). After replacing the column data of the generated SummarizedExperiment object with a custom, descriptive data frame was converted to a DESeqDataSet object with experimental groups corresponding to cell type and individual using the identically named function from the DESeq2 package (Love et al., 2014). Human samples were put through the same analysis separately to avoid forcing similarities in expression.
The non-human primate (NHP) data set was filtered to only include transcripts with more than one read across all NHP samples and subsequently analyzed for differential expression using the DESeq function of the DESeq2 package (Love et al., 2014). This creates a DESeqDataSet object that has estimated size factors and dispersions. Plots comparing mean expression of one condition to the relative log2 fold change of another were generated for each comparison using the plotMA function from the DESeq2 package and genes with an adjusted p-value <0.05 were colored red. The data frames containing the relative expression values, p-values, and adjusted p-values of each gene for each comparison were saved at this point.
Returning to the filtered NHP DESeqDataSet with estimated size factors and dispersions, the rlog function from the DESeq2 package was used in order to reduce the range of variances across mean expression values and allow for more accurate clustering of samples. The count data (assay) of the DESeqDataSet was transposed and supplied to the built-in dist R function to calculate the distance between samples. The resulting distances were converted to a matrix and supplied to the pheatmap function of the identically named package while also specifying that the original distances be used as the clustering distances for the samples. The rlog modified dataset was supplied to the plotPCA function from the DESeq package (Li and Durbin, 2009) to calculate the variation between samples and grouped by cell type and individual. Visualization was done using ggplot2 as described in Love et al. 2015.
Returning to the data frames containing adjusted p-values for each pairwise comparison, genes were identified that had an adjusted p-value <0.05, making them significantly differentially expressed. The complete (unfiltered) DESeqDataSet for both human and NHP samples had size factors and dispersion estimates calculated and were variance stabilized using the DESeq and rlog functions from the DESeq2 package (Love et al., 2014). For each species, the average rlog expression value was calculated for each gene. Before continuing the analysis, the set of genes was subset to those previously identified as differentially expressed in at least one of the NHP pairwise comparisons. For each remaining gene, the average rlog expression for each cell type in each species was calculated and compared to the mean rlog expression of that gene in order to calculate the deviation from the mean for each cell type. At this point, the ensembl gene games were converted to external gene names (when available) using the biomaRt package. Finally, scatterplots were generated using ggplot2 for each set of cell types comparable across species. The average deviation from the rlog mean expression value in the NHP specific cell type samples was plotted against the average deviation from the rlog mean expression value in the corresponding human cell type samples, so each dot represents a single gene. Genes of interest were colored red and labeled. The number of genes falling within each quadrant was also calculated.
Autologous NHP transplants and ex vivo engineering of HSPCs. Autologous NHP transplants, priming (mobilization), collection of cells and genetic engineering were conducted consistent with previously published protocols (Trobridge et al., 2008). Briefly, animals were pre-treated with G-CSF and SCF for 4 days to prime the BM. On day 4 after priming BM aspirates were performed, CD34+ fractions isolated, and cells plated into StemSpan SFEM containing 1% penicillin/streptomycin (P/S, Life Technologies) supplemented with SCF, TPO, and FLT3-L 100 ng/ml each. Cells were prestimulated overnight and re-plated in culture medium containing 4 μg/ml protamine sulfate, and 1 μg/ml Cyclosporine A onto flasks coated with CH296 (retronectin) for transduction with lentiviral vectors (MOI 10). A second dose of lentivirus (MOI 10 IU/cell) was added after 6-8 hours for overnight culture. Next day, cells were collected, residual virus removed, and washed cells re-plated in culture medium supplemented with prostaglandin E2 (PGE2). After 2 hours, cells were collected and prepared for infusion.
Neutrophils: The day of neutrophil engraftment is defined as a minimum of 500 neutrophils per μl peripheral blood (lower limit for engraftment: LLE) for a duration of at least 3 consecutive days. The duration of GCSF administration was not considered in this definition and is indicated by the yellow bar in each graph. Lower limit of normal (LLN) neutrophil counts in non-transplanted animals is 1,800 per μl.
Platelets: The day of platelet engraftment is defined as a minimum of 20,000-50,000 platelets per μl peripheral blood for a duration of at least 7 consecutive days, and trending toward a self-sustained increase in platelet counts without transfusion reaching greater than 50,000 platelets per μl. Lower limit of normal for platelet counts in non-transplanted animals is 260,000 per μl.
Engraftment failure means no sustained platelet counts above 50,000/mcL without transfusion support over the first 100 days after transplant. Additionally, drop of ANC to <500/mcL requiring G-CSF support, which became less effective over the first 100 days after transplant.
NHP Animal Housing and Care/Ethics statement. Healthy juvenile pigtail macaques (Macaca nemestrina) as well as juvenile rhesus macaques (Macaca mulatta under conditions approved by the American Association for the Accreditation of Laboratory Animal Care. All experimental procedures performed were reviewed and approved by the Institutional Animal Care and Use Committee. This study was carried out in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health (“The Guide”) and monkeys were randomly assigned to the study. This included at least twice-daily observation by animal technicians for basic husbandry parameters (e.g. food intake, activity, stool consistency, and overall appearance) as well as daily observation by a veterinary technician and/or veterinarian. Animals were housed in cages approved by “The Guide” and in accordance with Animal Welfare Act regulations. Animals were fed twice daily, and were fasted for up to 14 hours prior to sedation. Environmental enrichment included grouping in compound, large activity, or run-through connected cages, perches, toys, food treats, and foraging activities. If a clinical abnormality was noted by WaNPRC personnel, standard WaNPRC procedures were followed to notify the veterinary staff for evaluation and determination for admission as a clinical case. Animals were sedated by administration of ketamine HCl and/or telazol and supportive agents prior to all procedures. Following sedation, animals were monitored according to WaNPRC standard protocols. WaNPRC surgical support staff are trained and experienced in the administration of anesthetics and have monitoring equipment available to assist: electronic monitoring of heart rate, respiration, and blood oxygenation; audible alarms and LCD readouts; monitoring of blood pressure, temperature, etc. For minor procedures, the presence or absence of deep pain was tested by the toe-pinch reflex. The absence of response (leg flexion) to this test indicates adequate anesthesia for this procedure. Similar parameters were used in cases of general anesthesia, including the loss of palpebral reflexes (eye blink). Analgesics were provided as prescribed by the Clinical Veterinary staff for at least 48 hours after the procedures, and could be extended at the discretion of the clinical veterinarian, based on clinical signs. Decisions to euthanize animals were made in close consultation with veterinary staff and were performed in accordance with guidelines as established by the American Veterinary Medical Association Panel on Euthanasia (2013). Prior to euthanasia, animals were first rendered unconscious by administration of ketamine HCl.
Preconditioning and supportive care for autologous NHP transplants. In parallel to cell processing, macaques were conditioned with fractionated, myeloablative total body irradiation of 1020 cGy from a 6 MV x-ray beam of a single-source linear accelerator located at the Fred Hutchinson Cancer Research Center South Lake Union Facility (Seattle, Wash., USA); irradiation was administered as a fractionated dose over the 2 days before cell infusion. During irradiation, animals were housed in a specially modified cage that provided unrestricted access for the irradiation while simultaneously minimizing excess movement. The dose was administered at a rate of 7 cGy/min delivered as a midline tissue dose. Granulocyte colony-stimulating factor was administered daily from the day of cell infusion until the animals began to show onset of neutrophil recovery. Supportive care, including antibiotics, electrolytes, fluids, and transfusions, was given as necessary, and blood counts were analyzed daily to monitor hematopoietic recovery.
Integration Site Analysis (ISA). Processing of gDNA to amplify integration loci included either LAM-PCR (Beard, et al., 2007) (animal T04228) or MGS-PCR (Beard, et al., 2014) methods (animals M05189, J02370, Z08103 and Z09132). A variety of next generation sequencing platforms were used depending on date of transplant and sample collection. Platforms included single end 454 GS FLX Titanium (Roche), single end Ion Torrent PGM, and paired end Illumina Miseq. A detailed list of samples is included in a dataset available for download (BioProject PRJNA357116). Integration sites were identified using a method similar to that described by Hocum et al. 2015. For Illumina data, the forward and reverse reads were stitched using PEAR with the -q 30 option to trim sequence reads after two bases with a quality score below 30 were observed (Zhang et al., 2014). Stitched FASTQ files and raw FASTA files were filtered using custom python scripts. Pairwise2 from the Bio module was used to confirm the presence of the LTR primer at the start of the sequence read using a gap open penalty of −2, a gap extension penalty of −1, and requiring a total mapping score of 24 or greater, equivalent to two mismatches or one insertion or deletion (indel). Presence or absence of the long terminal repeat (LTR) region was determined using Pairwise2 to align a known 22 base pair sequence from the LTR region to the sequence read using the same gap penalties described previously and requiring a total mapping score of 20 or greater, corresponding to two mismatches or one indel. To remove reads representing vector sequences (as opposed to genomic sequences) a known 24 base pair sequence from the LV backbone was aligned to the sequence read using Pairwise2 and the same settings as described for primer alignment. Reads containing the primer sequence and the LTR sequence but not the vector sequence were then trimmed at the end of the aligned LTR sequence and output in FASTQ or FASTA format depending on the input format. The Macaca mulatta reference genome (rheMac3, GCA_000230795.1, October 2010) provided by the Beijing Genomics Institute, Shenzhen was downloaded from the UCSC genome browser (http://genome.ucsc.edu/) (Kent, et al., (2002). Genome research). Filtered and trimmed sequence reads were aligned to the reference genome using BLAT with options -out=blast8, -tileSize=11, -stepSize=5, and -ooc=rh11-2253.00c (Kent, et al., (2002). BLAT—the BLAST-like alignment tool). The rh11-2253.occ file includes a list of 11-mers occurring at least 2,253 times in the genome to be masked by BLAT and was generated using the following command: $blat rheMac3.2 bit/dev/null/dev/null -tileSize=11 -stepSize=5 -makeOoc=rh11-2253.00c -repMatch=2253 as recommended by UCSC [http://genome.ucsc.edu/goldenpath/help/blatSpec.html and http://genome.ucsc.edu/FAQ/FAQblat.html#blat6]. Resulting blast8 files were parsed using a custom python script. The blast8 files contained multiple possible alignments for each sequence read, so any sequence read with a secondary alignment with percent identity up to 95% of the best alignment was discarded. Sequence reads were then grouped based on their genomic alignment positions and orientation (sense (+) vs. antisense (−)). Any alignments within 5 base pairs of one another with identical orientations were considered to originate from the same IS; the genomic position with the greatest number of contributing sequence reads is reported as the IS. Multiple sequencing runs of the same sample were combined using a custom python script by combining the number of sequence reads for each genomic position.
Persistence Analysis. For each sample, clone contributions were normalized by converting the number of sequence reads to frequencies for each sample. A filter was applied to only retain clones with a contribution of three or more sequence reads, then only those clones detected <3 months after transplant. For each subsequent sample, the sum of early engrafting clone contributions was calculated. Finally, all samples collected within the time frame were grouped for each animal. An example analysis is as follows: In animal J02370 there are three samples available from the first 3 months after transplant. 3,946, 1,633, and 93,885 integration site (IS)-associated sequence reads in samples from 29, 60, and 64 days after transplant respectively were identified. These IS-associated reads correspond to 1,615, 620, and 5,055 unique IS respectively. Some IS were identified in multiple samples, thus a total of 6,422 unique IS were identified between 0 and 3 months after transplant. These 6,422 unique IS account for 100% of the IS-associated sequence reads observed in samples from the first 3 months after transplant. However, only 527, 209, and 2,201 IS are represented by three or more sequence reads in each sample respectively. Again, some IS were identified in multiple samples, thus a total of 2,634 unique IS are represented by three or more sequence reads in samples from the first 3 months after transplant. These 2,634 clones are deemed early repopulating clones, and account for 63.7%, 65.8%, and 96.4% of IS associated sequence reads observed in the three samples from the first 3 months after transplant, making the average frequency of early repopulating clones in this time frame 75.3%. For the second time frame of interest (>3 months after transplant, but <12 months after transplant), there is one sample available (109 days after transplant). In this sample, 101,926 IS-associated reads representing 5,681 unique IS were found. Of the 5,681 IS-associated reads, 885 were also early repopulating clones, however only 776 of those were represented by three or more sequence reads. The 776 clones that are early repopulating clones and represented by three or more sequence reads account for 76.3% of IS-associated reads from the sample 109 days after transplant, giving the frequency of early repopulating clones observed in the second time frame. This process is repeated for the third and fourth time frames of interest (12-24 months after transplant and >24 months after transplant) to obtain an average frequency of early repopulating clones of 87.2% and 94.6%, respectively.
Identifying HSC Signatures. The HSC signature was defined as a clone signature present in more than one PB or BM cell lineage at a single time point more than 6 months after transplant and detected in any other sample at any other time point. A custom R script was used to identify HSC clone signatures, and to generate contribution graphs. All files for a given animal were read into R and sample clone contributions were normalized by converting to frequencies. Clones shared between subsets were identified as HSC clones and remaining samples were parsed to identify HSC clones present.
HSC Clone Contribution Graphs. HSC clone contributions were determined by dividing the number of sequence reads for each clone by the total number of HSC clone sequence reads for the sample. Unallocated clones were noted. The mean maximum frequency of HSC clones was calculated. One animal, Z09132, had 676 clones contributing above the mean maximum frequency of HSC clones, thus only the top 100 most abundant HSC clones were displayed due to color limitations. A data frame was constructed including three columns: (1), days after transplant; (2), clone frequency in the sample; (3), clone identifier (genomic locus or barcode). The data frame was visualized using the R package ggplot2.
Results. Persistence of Early Clones Over Years after Transplant. The time to full, multilineage reconstitution in the PM model was first established by discreet analysis of hematopoietic subsets in five transplanted animals (
To study the kinetics of individual blood cell clones in autologous CD34+ hematopoietic stem and progenitor cell (HSPC) grafts, engraftment of individual LV gene-modified cell clones were retrospectively analyzed by high-throughput retrovirus ISA (
Early Engraftment of Persistent HSC Clones. To deduce whether any of these early engrafting and persistent clones displayed HSC biology in vivo, the specific clone signature (i.e. genomic locus of LV integration) had to be detected in multiple mature cell lineages late after transplant and detected at additional time points. Clone signatures shared between short-lived granulocytes or monocytes and longer-lived B cells or T cells were analyzed at time points months after transplant in three of five animals (
Phenotypical analysis of NHP HSPC subpopulations. A great variety of cell surface markers have been described for the quantification and isolation of functionally distinct human HSPC populations (
No cross-species reactivity or marking of distinct subpopulations was observed for candidate human HSPC cell surface markers CD38 (Terstappen et al., 1991), CD49f (Notta et al., 2011), CD133 (Yin et al., 1997), and CD135 (Doulatov et al., 2010). Thus, a focus on alternate HSPC markers including CD34 (Civin et al., 1984), CD45RA (Lansdorp et al., 1990), CD90 (Majeti et al., 2007), CD117 (Kikushige et al., 2008), and CD123 (Manz et al., 2002), which demonstrated cross-reactivity in NHP ssBM was chosen. Using these markers nine (I-IX) phenotypically distinct subpopulations within CD34+ cells from PM and RM ssBM (
The average frequency of CD34-expressing progenitors in ssBM and pBM, was 5.8±2.9% in PM and 2.2±0.7% in RM (
Proliferative potential of defined NHP HSPC subpopulations. The ability to self-renew is a classical definition of a true HSC, thus the proliferation potential of disclosed HSPC subpopulations was first examined. In order to investigate the proliferation potential, PM subpopulations I-IX from ssBM were purified, separately cultured for three days, and the arising progeny were enumerated and analyzed by flow cytometry. All subpopulations lost CD34, CD90 and CD117 expression and gained CD45RA expression upon culture (
Based on these cell surface marker phenotypes, proliferation potential analyses, and reported lineage relationships in human hematopoietic cells, a hierarchical organization of NHP HSPCs, with fraction VII being the most primitive HSPC population generating fraction VIII with a concomitant loss of CD90 expression was predicted (
Early segregation of erythroid potentials into CD34low and megakaryocytes into CD123+ fractions. To validate the proposed lineage relationships, functional in vitro assays were then applied to the phenotypically defined HSPC subpopulations to analyze and compare erythroid, myeloid and lymphoid lineages in the NHP with recently proposed models for human hematopoiesis.
To determine the myeloid, erythroid and erythro-myeloid differentiation potential of PM and RM ssBM, pBM, and UCB-derived HSPCs, sorted populations were introduced into CFC assays supporting differentiation of CFU-G, CFU-M, CFU-GM, BFU-E as well as CFU-MIX potential. Shapes and sizes of colonies (
The frequency of individual cells with colony-forming potential in NHP HSPC subpopulations ranged from 1% to 40%, with the highest CFC frequencies observed in Populations I, IV, V, VII and VIII (
To test the origin of megakaryocyte potential, ssBM-derived PM HSPCs were studied in megakaryocyte differentiation assays. Generation of megakaryocyte colonies (
Together, these data indicate that in CFC and megakaryocyte assays NHP erythroid potential segregates into CD34low cells (Population II) and megakaryocyte potential is restricted to CD123+ cells (Population IX), whereas CD45RA+ HSPCs (Populations V and VI) are lacking erythroid and megakaryocytic differentiation potentials.
Enrichment of primitive HSPCs in CD90+ cell populations. The formation of colonies containing cobblestone area forming cells (CAFCs) is suggested to represent primitive and multipotent HSPCs (de Kruijf et al., 2010; Ploemacher et al., 1989). Closer examination of primary CFC assays reveals that Populations VII and VIII contained clusters of CAFCs (
These data show that primitive NHP HSPCs with erythroid, myeloid, megakaryocyte and secondary colony forming-potential are enriched in CD90+ subpopulations (Population VII).
CD45RA+ HSPC populations are restricted to lympho-myeloid potentials. To analyze the segregation of lymphoid potentials in NHP-hematopoiesis, sort-purified ssBM-derived PM subpopulations were introduced into functional assays that support the differentiation of human HSPCs into T cells, B cells and/or NK cells.
For T cell assays, subpopulations were co-cultured with the murine stromal cell line OP9 stably expressing the Notch-Ligand Delta-like 1 as described previously (La Motte-Mohs et al., 2005). NHP ssBM-derived HSPCs with T cell differentiation potential up-regulated expression of the early lymphoid progenitor markers CD2 and CD5, and CD3 and CD4 were expressed on more mature T cells (
To test whether subpopulations containing T cell potentials can also give rise to B and NK cells, single, sort-purified HSPCs were introduced into a previously described clonogenic, multi-lineage readout (MS-5 assay) supporting lymphoid and myeloid differentiation (Doulatov et al., 2010).
A total of 1,914 flow-sorted single cells out of 4 independent ssBM samples were co-cultured for 5 weeks with the murine stromal cell line MS-5, the colony-forming potential evaluated microscopically, and the phenotype of progeny determined by flow-cytometry (Experimental schema shown in
The frequency of HSPCs with clonogenic colony-forming potential following expansion and differentiation in the MS-5 co-culture ranged from 5.7±2.4% in Population IX up to 45.8±7.9% in Population VIII (
Besides mature granulocytes, monocytes and NK cells, the MS-5 assay supported the maintenance and expansion of CD34+ HSPCs forming characteristic cobblestones previously observed in CFC assays (
These data confirm that lymphoid lineages in the NHP exclusively segregate into CD45RA+ cell Populations (VI) also containing granulocyte and macrophage/monocyte capabilities but lacking erythro-megakaryocytic potentials.
Unique transcriptome in NHP stem cells and committed progenitors. Expression of key molecules and activation of distinct biological pathways has been described for more primitive HSCs/MPPs and committed progenitor cells (Notta et al., 2015; Paul et al., 2015). To examine the NHP hematopoietic transcriptome, subpopulations of GCSF/SCF-primed PM-HSPCs either harvested from the bone marrow (pBM) or collected by apheresis (peripheral blood stem cells: PBSCs) were sort-purified for RNA extraction (
RNA-seq data was aligned to the rhesus (rhemac3) and the human (hg38) genome with 81-93% and 67-91% mapped reads, respectively (
Principal component analysis (
To identify genes differentially/uniquely expressed in functionally distinct NHP HSPC subpopulations, a pair-wise comparison of gene expression levels was next performed. Confirming the greatest distance within the unsupervised hierarchical clustering (
Consistent with the phenotypical and functional analyses, CD34+CD45RA−CD90+CD117+ (Population VII) NHP HSPCs showed a transcriptional profile consistent with more primitive HSC, whereas CD34+CD45RA+CD117+ (Population V) progenitor transcriptomes were consistent with lympho-myeloid lineages.
The transcriptome of human and NHP HSPC subpopulations is evolutionarily conserved. Nonhuman primates share a close evolutionary relationship with humans and are considered to be a clinically relevant model system to study HSC biology and treatments for hematopoietic diseases (Donahue et al., 2005). To evaluate whether phenotypically and functionally defined human HSPC fractions correspond to the newly identified NHP HSPC subpopulations, the transcriptome of human and NHP HSPC subpopulations was compared. Representing NHP HSPC Populations VII, VIII, and V, human HSC- (CD34+CD45RA−CD90+CD133+), MPP- (CD34+CD45RA−CD90−CD133−), and LMP-enriched (CD34+CD45RA+CD90−CD133−) fractions were sort-purified from two independent GCSF-primed healthy PBSC donors for RNA extraction and sequencing (
To determine the overlap of gene expression and identify shared stem cell programs between human and NHP HSPCs, the focus was on differentially expressed genes previously identified in the pair-wise comparison of NHP HSPCs (
Comparison of RNA expression in corresponding HSPC subpopulations from human and NHP revealed highly conserved patterns of expression for 72.7% (VII vs. HSC), 58.3% (VIII vs. MPP) and 73.0% (V vs. LMP) of differentially expressed genes (
CD34+CD45RA−CD90+ NHP cells fractions display multilineage engraftment potential. To evaluate engraftment, competitive reconstitution experiments were performed in the myeloablative, autologous NHP stem cell transplant model (
Enriched, purified and transduced cell fractions from all three NHPs maintained marker expression (
All fractions were pooled and infused into autologous recipient animals after myeloablative total body irradiation (TBI; 1020 cGy). Combined fractions (i+ii+iii) resulted in total cell doses of 1.68 million (Z13314), 1.73 million (Z14004), 1.12 million (Z13264) and 1.84 million (Z15086) cells per kg body weight (Table 3).
PB absolute neutrophil counts (ANC) and platelet counts rapidly recovered in all animals within 9-10 and 10-20 days, respectively (
CD34+CD45RA−CD90+ cells rapidly reconstitute the bone marrow stem cell niche. Another hallmark of HSCs is the ability to migrate into and reconstitute the BM niche. Thus, the BM compartment of transplanted animals were comprehensively analyzed (
Within 5-8 weeks after transplant, all three animals demonstrated robust engraftment of both unmodified (fluorophore−) and gene-modified (fluorophore+) WBCs and HSPCs in the BM (
Subsequent purification and functional analysis of gene-modified and unmodified HSPC subpopulations showed similar frequencies of CFCs with an expected enrichment of CFU-Gs in fraction i, CFU-MIX and BFU-Es in fraction ii, and CFU-Ms in fraction iii (
True Multilineage Reconstitution Demonstrated by Clonal Analysis. To test whether true multipotent HSC were represented by this early engraftment of fraction i cells, fluorophore+ PB cell lineages were sort-purified from two animals at 4 months (Z13264, mCh+) and 6.5 months (Z14004, GFP+) post-transplant for ISA (
Clonal analysis demonstrated highly polyclonal engraftment with 6,152 and 18,034 unique clones signatures detected for animals Z13264 and Z14004, respectively (
Given this observation, the range of fraction i cell doses required for hematopoietic recovery after myeloablative transplant in this animal model was next determined.
Transplanted number of CD34+CD45RA−CD90+ cells per kg body weight correlates with hematopoietic recovery. To evaluate whether the number of transplanted CD34+CD45RA−CD90+ cells correlates with engraftment, 15 animals for whom HSPC flow cytometry data were available were retrospectively analyzed (Table 4,
From hematologic data, it was observed that clinically relevant threshold levels of neutrophils (500/mcL) and platelets (20,000/mcL) could be achieved after transplant in all animals (
The transplanted dose of CD34+ HSPCs, CD34+CD45RA−CD90+ (HSC-enriched), CD34+CD45RA−CD90− (MPP-enriched) and CD34+CD45RA+CD90− (LMP-enriched) cells was evaluated for all animals by determining the frequency of CD34+CD45RA−CD90+, CD34+CD45RA− CD90− and CD34+CD45RA+CD90− cells (
Animals displaying engraftment success (n=13) received nearly 5 times the mean cell dose of the HSC-enriched cell fraction compared to animals displaying engraftment failure (n=2; p value=0.019), whereas no significant difference were observed for CD34+ or the MPP- and LMP-enriched cell fractions (
Notably, a strong correlation was observed between the CD34+CD45RA−CD90+ cell dose received and the onset of neutrophil and platelet recovery in animals displaying engraftment success (
CD34+CD45RA−CD90+ cells are highly enriched for CD34+CD38−/low cells in human mobilized PBSCs and UCB. To evaluate whether the assessment of CD34 in combination with CD45RA and CD90 allows for enrichment of a similar cell fraction in humans, the strategy was tested in human GCSF-mobilized PBSCs (
Current autologous stem cell transplantation and gene therapy/editing strategies are limited by the inability to identify a true stem cell population that reliably predicts engraftment. For gene editing and gene therapy approaches, the ability to target a specific HSC pool and predict engraftment levels of the gene modified cells is a major advance, reducing the cost of goods required for manufacture, as well as the off-target effects that compromise safety and efficacy of these treatments. To do this effectively requires a rapid assay to identify and enumerate cells of interest, in this case, the HSC. Additionally, this requires data demonstrating a strong, direct correlation between the number of HSC infused and the level of engraftment after transplant.
In order to determine the quality of a stem cell product and predict the likelihood of long-term engraftment before administration, a great variety of “potency assays” have been proposed. However, identifying, characterizing and quantifying HSC populations for the treatment of hematological diseases and disorders has been difficult to do ex vivo since the hallmark functionality of these cells is the ability to produce all blood cell lineages for the lifetime of a recipient (Harper and Rich 2015, Patterson et al. 2015, Rich 2015).
A widely used potency assay, predominantly used for banked/frozen stem cell products such as umbilical cord blood (UCB) or autologous stem cell transplants, is the CFU or CFC assay. Increased numbers of CFUs/CFCs were shown to be a predictor of potency, defined as hematopoietic recovery in myeloablated patients by 42 days after infusion (Page et al. 2011, Page et al. 2012). Unfortunately, the 2 week duration of the CFU/CFC assay does not allow for real-time quality control of fresh or thawed stem cell products immediately before infusion. Furthermore, the CFU/CFC assay is limited in its ability to read-out all hematopoietic cell lineages. The standard assay is biased towards hematopoietic stem/progenitor cells (HSPCs) with erythroid, myeloid and erythro-myeloid differentiation potential and does not support lymphoid lineages. To evaluate the lymphoid potential of cell products, a separate assay must be performed. In this assay, cell products are first co-cultured with a cell line and then plated into CFU/CFC assays, which lengthens the entire evaluation period even further and still does not support B cell development.
To overcome these major limitations of the CFU/CFC assay (i.e. slow turn around and incomplete lineage representation), many groups have assessed cell surface marker(s) in bone marrow or blood cell populations and tried to correlate these with CFU/CFC potency. Flow cytometry-based evaluation of a cell surface marker phenotype can be performed in real-time, but must be supported by in vitro functional assays, including CFU/CFC formation. However, the most convincing functional data would be in vivo data in a transplant setting. A most recent publication by Shoulars et al. describes a strong correlation (r=0.78) of CD34+ HSPCs expressing high levels of the enzyme aldehyde dehydrogenase (ALDH) with CFU/CFC frequencies in cryopreserved and thawed UCB (Shoulars et al. 2016). Even though the number of ALDHhigh expressing HSPCs has been shown to correlate with CFU/CFC frequency, correlation of transplant outcome, neutrophila/platelet recovery and multi-lineage long-term engraftment with ALDH-expression has yet to be demonstrated. Moreover, it is unknown if the ALDHhigh correlation will apply to more common sources of CD34+ cells for gene and cell therapy such as bone marrow and growth factor mobilized peripheral blood.
Several groups have used animal models and transplant data in patients in an attempt to correlate potency measures with functional performance (Sartor et al. 2007, Chang et al. 2009, Chang et al. 2009, Trobridge and Kiem 2010, Watts et al. 2012, Tanner et al. 2014). These studies underscore a major problem in defining in vivo potency of HSC products: broad variability in the time to engraftment as described by the day of neutrophil and platelet recovery. Furthermore, current potency measures do not predict onset and kinetics of engraftment and do not define a minimum number of HSC required to prevent engraftment failure.
Here it is demonstrated for the first time a flow-cytometry based strategy/potency-assay to analyze and predict the onset of neutrophil and platelet recovery in the setting of myeloablative autologous nonhuman primate HSC transplantation. While the examples herein are used in the context of myeloablative conditioning this model can be extended to alternative non-genotoxic conditioning regimens. From this data, the minimum cell number of an HSC-enriched phenotype per kg body weight required for sustained multi-lineage long-term engraftment with recovery of all blood cell lineages in this transplant setting was defined. It is envisioned this flow-cytometry based strategy/potency-assay can also be used as a quality control measure to ensure stem cell aliquots are viable for transplantation. Stem cell aliquots is an aliquot, vial, or other container storing a plurality of cells. These stem cell aliquots can be from fresh, frozen, culture-expanded, gene-modified HSCs. The importance of being able to predict engraftment prior to transplantation for humans and NHPs reduces the risk of a failed transplant and has the ability to significantly reduce medical costs associated with these failed engraftments.
See
As will be understood by one of ordinary skill in the art, each embodiment disclosed herein can comprise, consist essentially of or consist of its particular stated element, step, ingredient or component. As used herein, the transition term “comprise” or “comprises” means includes, but is not limited to, and allows for the inclusion of unspecified elements, steps, ingredients, or components, even in major amounts. The transitional phrase “consisting of” excludes any element, step, ingredient or component not specified. The transition phrase “consisting essentially of” limits the scope of the embodiment to the specified elements, steps, ingredients or components and to those that do not materially affect the embodiment. As used herein, a material effect would cause a statistically-significant reduction in an isolated HSC population's ability to demonstrate multi-lineage potential and engraftment.
Unless otherwise indicated, all numbers expressing quantities of ingredients, properties such as molecular weight, reaction conditions, and so forth used in the specification and claims are to be understood as being modified in all instances by the term “about.” Accordingly, unless indicated to the contrary, the numerical parameters set forth in the specification and attached claims are approximations that may vary depending upon the desired properties sought to be obtained by the present invention. At the very least, and not as an attempt to limit the application of the doctrine of equivalents to the scope of the claims, each numerical parameter should at least be construed in light of the number of reported significant digits and by applying ordinary rounding techniques. When further clarity is required, the term “about” has the meaning reasonably ascribed to it by a person skilled in the art when used in conjunction with a stated numerical value or range, i.e. denoting somewhat more or somewhat less than the stated value or range, to within a range of ±20% of the stated value; ±19% of the stated value; ±18% of the stated value; ±17% of the stated value; ±16% of the stated value; ±15% of the stated value; ±14% of the stated value; ±13% of the stated value; ±12% of the stated value; ±11% of the stated value; ±10% of the stated value; ±9% of the stated value; ±8% of the stated value; ±7% of the stated value; ±6% of the stated value; ±5% of the stated value; ±4% of the stated value; ±3% of the stated value; ±2% of the stated value; or ±1% of the stated value.
Notwithstanding that the numerical ranges and parameters setting forth the broad scope of the invention are approximations, the numerical values set forth in the specific examples are reported as precisely as possible. Any numerical value, however, inherently contains certain errors necessarily resulting from the standard deviation found in their respective testing measurements.
The terms “a,” “an,” “the” and similar referents used in the context of describing the invention (especially in the context of the following claims) are to be construed to cover both the singular and the plural, unless otherwise indicated herein or clearly contradicted by context. Recitation of ranges of values herein is merely intended to serve as a shorthand method of referring individually to each separate value falling within the range. Unless otherwise indicated herein, each individual value is incorporated into the specification as if it were individually recited herein. All methods described herein can be performed in any suitable order unless otherwise indicated herein or otherwise clearly contradicted by context. The use of any and all examples, or exemplary language (e.g., “such as”) provided herein is intended merely to better illuminate the invention and does not pose a limitation on the scope of the invention otherwise claimed. No language in the specification should be construed as indicating any non-claimed element essential to the practice of the invention.
Groupings of alternative elements or embodiments of the invention disclosed herein are not to be construed as limitations. Each group member may be referred to and claimed individually or in any combination with other members of the group or other elements found herein. It is anticipated that one or more members of a group may be included in, or deleted from, a group for reasons of convenience and/or patentability. When any such inclusion or deletion occurs, the specification is deemed to contain the group as modified thus fulfilling the written description of all Markush groups used in the appended claims.
Certain embodiments of this invention are described herein, including the best mode known to the inventors for carrying out the invention. Of course, variations on these described embodiments will become apparent to those of ordinary skill in the art upon reading the foregoing description. The inventor expects skilled artisans to employ such variations as appropriate, and the inventors intend for the invention to be practiced otherwise than specifically described herein. Accordingly, this invention includes all modifications and equivalents of the subject matter recited in the claims appended hereto as permitted by applicable law. Moreover, any combination of the above-described elements in all possible variations thereof is encompassed by the invention unless otherwise indicated herein or otherwise clearly contradicted by context.
Furthermore, numerous references have been made to patents and printed publications throughout this specification. Each of the above-cited references and printed publications are individually incorporated herein by reference for their particular cited teachings.
In closing, it is to be understood that the embodiments of the invention disclosed herein are illustrative of the principles of the present invention. Other modifications that may be employed are within the scope of the invention. Thus, by way of example, but not of limitation, alternative configurations of the present invention may be utilized in accordance with the teachings herein. Accordingly, the present invention is not limited to that precisely as shown and described.
The particulars shown herein are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of various embodiments of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for the fundamental understanding of the invention, the description taken with the drawings and/or examples making apparent to those skilled in the art how the several forms of the invention may be embodied in practice.
Definitions and explanations used in the present disclosure are meant and intended to be controlling in any future construction unless clearly and unambiguously modified in the following examples or when application of the meaning renders any construction meaningless or essentially meaningless. In cases where the construction of the term would render it meaningless or essentially meaningless, the definition should be taken from Webster's Dictionary, 3rd Edition or a dictionary known to those of ordinary skill in the art, such as the Oxford Dictionary of Biochemistry and Molecular Biology (Ed. Anthony Smith, Oxford University Press, Oxford, 2004).
This application is a continuation of U.S. patent application Ser. No. 16/310,773, filed Dec. 17, 2018, which is a U.S. National Phase application based on International Patent Application No. PCT/US2017/037967, filed Jun. 16, 2017, which claims priority to U.S. Provisional Patent Application No. 62/351,761, filed on Jun. 17, 2016, and U.S. Provisional Patent Application No. 62/428,994, filed Dec. 1, 2016, each of which is incorporated herein by reference in their entirety as if fully set forth herein.
This invention was made with Government support under HL098489 awarded by the National Institutes of Health. The Government has certain rights in this invention.
| Number | Date | Country | |
|---|---|---|---|
| 62428994 | Dec 2016 | US |
| Number | Date | Country | |
|---|---|---|---|
| Parent | 16310773 | Dec 2018 | US |
| Child | 18057098 | US |
