Patent Application
20240084257
A computer readable form of the Sequence Listing is filed with this application by electronic submission and is incorporated into this application by reference in its entirety. The Sequence Listing is contained in the file created on Sep. 5, 2023, having the file name “22-0629-US.xml” and is 37 kb in size.
Elucidation of developmental pathways using human embryonic stem cells and induced pluripotent stem cells over the past 25 years have enabled production of therapeutically useful amounts of specific cell types that can, inter alia, provide allogenic sources of cells specific for individual patients. A specific example of such cell types is produced during hematopoiesis to provide a number of important components of blood function and homeostasis, including for example cells involved in immunological surveillance and function. One such cell is the natural killer or NK cell, a species of white blood cell in the lymphoid lineage which is characterized by having granules containing enzymes that can kill tumor cells or cells infected with a virus. Yet another are megakaryocytes, cells found in bone marrow that are responsible for producing thrombocytes (platelets).
Another consequence of the ability to study and manipulate stem cells and particularly hematopoietic stem cells has been an understanding of endogenous proteins produced during differentiation that effect progression to final effector cells like NK cells. These proteins, including transcription factors are responsible for activating specific genes in developmental pathways leading to particular differentiation outcomes. One example of such transcription factors is the SOXF family of transcription factors, comprising SOX7, SOX17 and SOX18, that have been recognized as critical regulators of angiogenesis, cardiovascular and hematopoietic development. See, for example, Lilly et al., 2017 SOXF transcription factors in cardiovascular development. Seminars in cell & developmental biology 63: 50-57.
Murine embryonic studies have shown that Sox7 is required for formation of the earliest multipotent hematopoietic progenitor cells (HPs) with erythro-myeloid potential. Gandillet et al., 2009, Sox7-sustained expression alters the balance between proliferation and differentiation of hematopoietic progenitors at the onset of blood specification. Blood.114: 4813-4822. Forced expression of Sox7 in cells from E7.5 mouse embryo or from in vitro differentiated mouse embryonic stem cells (ESCs) promotes self-renewal of early CD41+ hemogenic progenitors with erythro-myeloid potential and blocks their differentiation. Lilly et al., 2016, Interplay between SOX7 and RUNX1 regulates hemogenic endothelial fate in the yolk sac. Development 143: 4341-4351. A similar phenotype was observed following overexpression of Sox18 in in vitro-differentiated mouse ESCs. Serrano et al., 2010, Contrasting effects of Sox17- and Sox 1 8-sustained expression at the onset of blood specification. Blood 115: 3895-3898. SOX17 has been shown using human embryonic stem cells to be a master regulator of HOXA and arterial programs in hemogenic endothelium (HE) and is required for the specification of HE with robust lympho-myeloid potential and DLL4+CXCR4+ phenotype resembling arterial HE at sites of HSC emergence. Jung et al., 2021, SOX17 integrates HOXA and arterial programs in hemogenic endothelium to drive definitive lympho-myeloid hematopoiesis. Cell Rep. 34(7):108758.
There is a need in this art to further elucidate functions of transcription factors in the SOXF family to develop reagents and methods for manipulating hematopoiesis in human stem cells to produce cells for therapeutic intervention and other purposes.
Provided herein are reagents and methods for manipulating pluripotent stem cells, and particularly human stem cells, for producing specific cell types resulting from hematopoietic differentiation. In specific embodiments, such cells are natural killer (NK) cells. In other specific embodiments are megakaryocytes. Specific embodiments of the methods provided herein result in enforced SOX18 expression in stem cells and hemogenic endothelial cells during the endothelial-to-hematopoietic transition. In particular, such enforced SOX18 expression produces preferential commitment to NK progenitor cells. In specific embodiments such NK progenitor cells are derived from multipotent hematopoietic progenitors having a phenotype of CD34+CD43+CD235a/CD41a−CD45−. In particular embodiments the invention provides such cells, inter alia, for use in immunotherapy.
Yet another aspect of the disclosure provides a pharmaceutical composition comprising NK cells produced by forced expression of SOX18 in hemogenic endothelium. In some embodiments the NK cell is a genetically modified cell such as a CAR-NK cell. In certain embodiments, CAR-encoding expression constructs are introduced into pluripotent stem cells (PSCs) and those cells differentiated to CAR-NK cells by forced expression of SOX18. In alternative embodiments NK cells are produced from PSCs and CAR-encoding expression constructs introduced into the NK cells thereby produced.
In still further aspects of the disclosure are provided megakaryocytes through forced expression of SOX18 in mesoderm and hemogenic endothelium.
These and other features, objects, and advantages of the present invention will become better understood from the description that follows. In the description, reference is made to the accompanying drawings, which form a part hereof and in which there is shown by way of illustration, not limitation, embodiments of the invention. The description of preferred embodiments is not intended to limit the invention to cover all modifications, equivalents, and alternatives. Reference should therefore be made to the claims recited herein for interpreting the scope of the invention.
The disclosure will be better understood and features, aspects, and advantages other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such detailed description refers to the following drawings.
The present disclosure is based, at least in part, on experimental demonstration that forced SOX18 expression in cells in the hematopoietic lineage preferentially promotes formation of progenitors of natural killer cells and megakaryocytes.
For the purposes of promoting an understanding of the principles of the disclosure, reference will now be made to embodiments and specific language will be used to describe the same. It will nevertheless be understood that no limitation of the scope of the disclosure is thereby intended, such alteration and further modifications of the disclosure as illustrated herein, being contemplated as would normally occur to one skilled in the art to which the disclosure relates.
As used in the specification, articles “a” and “an” are used herein to refer to one or to more than one (i.e., at least one) of the grammatical object of the article. By way of example, “an element” means at least one element and can include more than one element.
“About” is used to provide flexibility to a numerical range endpoint by providing that a given value can be “slightly above” or “slightly below” the endpoint without affecting the desired result. The term “about” in association with a numerical value means that the numerical value can vary by plus or minus 5% or less of the numerical value.
Throughout this specification, unless the context requires otherwise, the word “comprise” and “include” and variations (e.g., “comprises,” “comprising,” “includes,” “including”) will be understood to imply the inclusion of a stated component, feature, element, or step or group of components, features, elements, or steps but not the exclusion of any other integer or step or group of integers or steps.
As used herein, “and/or” refers to and encompasses any and all possible combinations of one or more of the associated listed items, as well as the lack of combinations where interpreted in the alternative (“or”).
Recitation of ranges of values herein are merely intended to serve as a succinct method of referring individually to each separate value falling within the range, unless otherwise indicated herein. Furthermore, each separate value is incorporated into the specification as if it were individually recited herein. For example, if a range is stated as 1 to 50, it is intended that values such as 2 to 4, 10 to 30, or 1 to 3, for example, are expressly enumerated in this disclosure. These are only examples of what is specifically intended, and all possible combinations of numerical values between and including the lowest value and the highest value enumerated are to be considered to be expressly stated in this disclosure.
The term “contacting” includes the physical contact of at least one substance to another substance.
As used herein, “treatment” refers to the clinical intervention made in response to a disease, disorder, or physiological condition of the subject or to which a subject can be susceptible. The aim of treatment includes the alleviation or prevention of symptoms, slowing or stopping the progression or worsening of a disease, disorder, or condition and/or the remission of the disease, disorder, or condition.
The terms “effective amount” or “therapeutically effective amount” refer to an amount sufficient to effect beneficial or desirable biological and/or clinical results. In other words, a “therapeutically effective” amount is an amount that will provide some alleviation, mitigation, or decrease in at least one clinical symptom in the subject.
The terms “express” or “expression” refer to transcription and translation of a nucleic acid coding sequence resulting in production of the encoded polypeptide. “Express” or “expression” also refers to antigens that are expressed on cell surfaces.
Unless otherwise defined, all technical terms used herein have the same meaning as commonly understood by a person of ordinary skill in the art to which this disclosure belongs.
As used herein, the term “subject” refers to both human and nonhuman animals. The term “nonhuman animals” of the disclosure includes all vertebrates, e.g., mammals and non-mammals, such as nonhuman primates, sheep, dog, cat, horse, cow, chickens, amphibians, reptiles, and the like. The human subject can be of any age (e.g., an infant, child, or adult).
The term “construct” refers to an artificially-designed segment of DNA that can be used to incorporate genetic material into a target cell (e.g., an hPSC).
The term “sequence identity” refers to the number of identical or similar nucleotide bases on a comparison between a test and reference oligonucleotide or nucleotide sequence. Sequence identity can be determined by sequence alignment of a first nucleic acid sequence to identify regions of similarity or identity to second nucleic acid sequence. As described herein, sequence identity is generally determined by alignment to identify identical residues. Matches, mismatches, and gaps can be identified between compared sequences by techniques known in the art. Alternatively, sequence identity can be determined without taking into account gaps as the number of identical positions/length of the total aligned sequence ×100. In one embodiment, the term “at least 90% sequence identity to” refers to percent identities from 90 to 100%, relative to the reference nucleotide sequence. Identity at a level of 90% or more is indicative of the fact that, assuming for exemplary purposes a test and reference polynucleotide sequence length of 100 nucleotides are compared, no more than 10% (i.e., 10 out of 100) of the nucleotides in the test oligonucleotide differ from those of the reference oligonucleotide. Differences are defined as nucleic acid substitutions, insertions, or deletions.
Any appropriate method can be used to detect expression of biological markers characteristic of cell types described herein. For example, the presence or absence of one or more biological markers can be detected using, for example, RNA sequencing (e.g., RNA- seq), immunohistochemistry, polymerase chain reaction, quantitative real time PCR (qRT-PCR), or other technique that detects or measures gene expression. RNA-seq is a high-throughput sequencing technology that provides a genome-wide assessment of the RNA content of an organism, tissue, or cell. Alternatively, or additionally, one can detect the presence or absence of, or measure the level of, one or more biological markers of HPCs using, for example, Fluorescence in situ Hybridization (FISH; see W098/45479 published October 1998), Southern blotting, Northern blotting, or polymerase chain reaction (PCR) techniques, such as qRT-PCR. In exemplary embodiments, a cell population obtained according to a method provided herein is evaluated for expression (or the absence thereof) of biological markers of HPCs such as CD34, CD45, CD43, and CD90. Quantitative methods for evaluating expression of markers at the protein level in cell populations are also known in the art.
The term “genetically engineered” as used herein refers to cells that have been manipulated using biotechnology to change the genetic makeup of the cells, including the transfer of genes within and across species boundaries to produce improved or non-naturally occurring cells. A human pluripotent stem cell, hemogenic endothelium, megakaryocytes or NK cells that contains an exogenous, recombinant, synthetic, and/or otherwise modified polynucleotide is considered to be a genetically engineered cell and, thus, non-naturally occurring relative to any naturally occurring counterpart. In some cases, genetically engineered cells contain one or more recombinant nucleic acids. In other cases, genetically engineered cells contain one or more synthetic or genetically engineered nucleic acids (e.g., a nucleic acid containing at least one artificially created insertion, deletion, inversion, or substitution relative to the sequence found in its naturally occurring counterpart). Procedures for producing genetically engineered cells are generally known in the art, for example, as described in Sambrook et al, Molecular Cloning, A Laboratory Manual (Fourth Edition), Cold Spring Harbor Press, Cold Spring Harbor, N.Y. (2012) and Doudna et al., CRISPR-Cas, A Laboratory Manual, Cold Spring Harbor Press, Cold Spring Harbor, N.Y. (2016).
A genetically engineered cell can be a cell that has been modified using a gene editing technique. Gene editing refers to a type of genetic engineering in which DNA is inserted, deleted, modified, or replaced in the genome of a living cell. In contrast to other genetic engineering techniques that can randomly insert genetic material into a host genome, gene editing can target the insertions to site specific locations (e.g., AAVS1 alleles). Examples of gene editing techniques including, but are not limited to, restriction enzymes, zinc finger nucleases, TALENs, and CRISPR-Cas9.
A genetically engineered cell can be a stem cell (e.g., a human pluripotent stem cell) or any of their differentiated progeny cells (e.g., mesoderm cells, hemangioblast cells, hemogenic endothelium cells, hematopoietic progenitor cells, megakaryocytes and NK cells) that have been modified to express. Any of the cells described herein can be genetically engineered. In some embodiments, a genetically engineered cell refers to a cell that is differentiated from a cell that has been genetically engineered.
The term “tumor cell” as used herein refers to abnormal cells that divide continuously. In some embodiments, the tumor cell is a solid tumor cell. A solid tumor is an abnormal mass of cells that typically does not contain cysts or a liquid area. Examples of solid tumors include, but are not limited to, sarcomas and carcinomas. Cancers of the blood (e.g., leukemias) typically do not form solid tumors. In some embodiments, the “tumor cell” is not a blood cancer cell. “Tumor cells” as used herein refers to a group of tumor cells and/or a single tumor cell.
Human pluripotent stem cells (hPSCs), either embryonic or induced, provide access to the earliest stages of human development and offer a platform on which to derive a large number of hematopoietic progenitor cells or blood cells for cellular therapy and tissue engineering. Accordingly, the methods provided herein can comprise differentiating human pluripotent stem cells under conditions that promote differentiation of mesodermal cells (e.g., arterial endothelial cells) into hematopoietic progenitor cells into megakaryocytes and NK cells.
Methods of differentiating hPSCs into progenitor mesoderm, hemogenic endothelium and hematopoietic progenitors are known in the art. In exemplary embodiments the culture medium to be used in any of the above-described differentiation methods comprises an IF9S medium, as described herein. In one embodiment, the IF9S medium to be used is the IF9S medium having the formulation set forth in Table 2. In some embodiments, any of the above-referenced cells (e.g., human pluripotent stem cells) are cultured on Tenascin C. In some embodiments, any of the referenced cells are seeded on a substrate treated with an amount of Tenascin-C sufficient to adhere 10,000 cells/cm2 to the substrate. In some embodiments, the Tenascin-C to be used is human Tenascin C. In some embodiments, the substrate is treated with Tenascin C at a concentration of at least about 0.25 μg/cm2 to 1 μg/cm2, e.g., 0.4 μg/cm2, 0.5 μg/cm2, 0.7 μg/cm2, 0.8 μg/cm2, or another concentration from at least about 0.25 μg/cm2 to 1 μg/cm2. In a preferred embodiment, the cells are cultured on plates coated with Collagen IV, as described in Uenishi et al., 2014, Stem Cell Reports 3: 1073-1084 and U.S. Pat. No. 9,938.499.
In some embodiments, in the cell culture medium to be used in the differentiation methods set forth herein, the concentration of: BMP4 is about 50 ng/ml to about 250 mg/ml; Activin A is about 10 ng/ml to about 15 ng/ml; FGF2 is about 10 ng/ml to about 50 ng/ml; LiCl is about 1 mM to about 2 mM; VEGF is about 20 ng/ml to about 50 ng/ml; SCF is about 50 ng/ml to about 100 ng/ml; TPO is about 50 ng/ml to about 100 ng/ml; IL-6 is about 50 ng/ml to about 100 ng/ml, and IL-3 is about 5 ng/ml to about 15 ng/ml.
In some embodiments, any of the above-referenced cells are cultured in a xeno-free cell culture medium. Of central importance for clinical therapies is the absence of xenogenic materials in the derived cell populations, i.e., no non-human cells, cell fragments, sera, proteins, and the like. Preferably, the present invention arrives at xenogen-free differentiated cells by use of Tenascin C or Collagen IV as a platform, which essentially replaces contact with OP9 cells used in earlier differentiation systems. In addition, the media disclosed herein are chemically defined and, in some embodiments, are made xeno-free, and incorporate human proteins, which can be produced using recombinant technology or derived from placenta or other human tissues in lieu of animal-derived proteins. In some embodiments, all proteins added to the medium are recombinant proteins.
As used herein, the term “mesoderm cell” refers to a cell having mesoderm-specific gene expression, capable of differentiating into a mesodermal lineage such as bone, muscle such as cardiac muscle, skeletal muscle, and smooth muscle (e.g., of the gut), connective tissue such as the dermis and cartilage, kidneys, the urogenital system, blood or hematopoietic cells, heart, and vasculature. Mesoderm-specific biomarkers include Brachyury (7). Culturing can take place on any appropriate surface (e.g., in two-dimensional or three-dimensional culture).
Medium and substrate conditions for culturing pluripotent stem cells, as used in the methods described herein, are well known in the art. In some cases, pluripotent stem cells to be differentiated according to the methods disclosed herein are cultured in mTESR-1 medium (StemCell Technologies, Inc., Vancouver, British Columbia.), E8 medium, or Essential 8 medium (Life Technologies, Inc.) on a MATRIGEL™ substrate (BD Biosciences, NJ) or Vitronectin (Life Technologies) according to the manufacturer's protocol.
As used herein, the term “albumin-free conditions” indicates that the culture medium used contains no added albumin in any form including, without limitation, Bovine Serum Albumin (BSA), any form of recombinant albumin, or any other animal albumin.
As used herein, the terms “chemically-defined medium” and “chemically-defined culture medium” also refer to a culture medium containing formulations of fully disclosed or identifiable ingredients, the precise quantities of which are known or identifiable and can be controlled individually. As such, a culture medium is not chemically-defined if (1) the chemical and structural identity of all medium ingredients is not known, (2) the medium contains unknown quantities of any ingredients, or (3) both. Standardizing culture conditions by using a chemically-defined culture medium minimizes the potential for lot-to-lot or batch-to-batch variations in materials to which the cells are exposed during cell culture. Accordingly, the effects of various differentiation factors are more predictable when added to cells and tissues cultured under chemically-defined conditions.
As used herein, the term “serum-free” refers to cell culture materials that do not contain serum or serum replacement, or that contains essentially no serum or serum replacement. For example, an essentially serum-free medium can contain less than about 1%, 0.9%, 0.8%, 0.7%, 0.6%, 0.5%, 0.4%, 0.3%, 0.2%, or 0.1% serum. “Serum free” also refers to culture components free of serum obtained from animal (e.g., fetal bovine) blood or animal-derived materials, which is important to reduce or eliminate the potential for cross-species viral or prion transmission. For avoidance of doubt, serum-containing medium is not chemically-defined.
Human pluripotent stem cells (e.g., human ESCs or iPS cells) can be cultured in the absence of a feeder layer (e.g., a fibroblast feeder layer), a conditioned medium, or a culture medium comprising poorly defined or undefined components. As used herein, “feeder-free” refers to culture conditions that are substantially free of a cell feeder layer. Cells grown under feeder-free conditions can be grown on a substrate, such as a chemically-defined substrate, and/or grown as an adherent culture. Suitable chemically-defined substrates include vitronectin.
A method of producing a hematopoietic progenitor cell can comprise culturing human pluripotent stem cells in a serum-free, albumin-free, chemically-defined culture medium that promotes differentiation to mesoderm. In this manner, pluripotent stem cell-derived mesodermal cells are differentiated according to the HPC differentiation methods provided herein, thus producing pluripotent stem cell-derived HPCs.
As used herein, “pluripotent stem cells” appropriate for use according to a method of the invention are cells having the capacity to differentiate into cells of all three germ layers. Suitable pluripotent cells for use herein include human embryonic stem cells (hESCs) and human induced pluripotent stem (iPS) cells. As used herein, “embryonic stem cells” or “ESCs” mean a pluripotent cell or population of pluripotent cells derived from an inner cell mass of a blastocyst. See Thomson et al., Science 282:1145-1147 (1998). These cells can express Oct-4, SSEA-3, SSEA-4, TRA-1-60, and TRA-1-81. Pluripotent stem cells appear as compact colonies comprising cells having a high nucleus to cytoplasm ratio and prominent nucleolus. ESCs are commercially available from sources such as WiCell Research Institute (Madison, WI.).
As used herein, “induced pluripotent stem cells” or “iPS cells” refers to pluripotent cell or population of pluripotent cells that can vary with respect to their differentiated somatic cell of origin, that can vary with respect to a specific set of potency-determining factors and that can vary with respect to culture conditions used to isolate them, but nonetheless are substantially genetically identical to their respective differentiated somatic cell of origin and display characteristics similar to higher potency cells, such as ESCs, as described herein. See, e.g., Yu et al., Science 318:1917-1920 (2007).
Induced pluripotent stem cells exhibit morphological properties (e.g., round shape, large nucleoli, and scant cytoplasm) and growth properties (e.g., doubling time of about seventeen to eighteen hours) akin to ESCs. In addition, iPS cells express pluripotent cell-specific markers (e.g., Oct-4, SSEA-3, SSEA-4, Tra-1-60, or Tra-1-81, but not SSEA-1). Induced pluripotent stem cells, however, are not immediately derived from embryos. As used herein, “not immediately derived from embryos” means that the starting cell type for producing iPS cells is a non-pluripotent cell, such as a multipotent cell or terminally differentiated cell, such as somatic cells obtained from a post-natal individual.
As set forth herein, NK cells and megakaryocytes can be preferentially produced, compared with T cells, by inducing expression in SOX18 in progenitor cells. Generally, preferential differentiation can be achieved by overexpressing SOX18 at a specific time (i.e., starting at day 2) and for a defined period (i.e., 2-8 days) during differentiation. SOX18 is a member of the Sry-related high mobility group domain (SOX) family of transcription factors and is key developmental regulator of endothelial and hematopoietic lineages. In the methods of the present invention, differentiating hPSCs are forced to overexpress SOX18 during the mesoderm differentiation by introducing an inducible SOX18 transgene into the population of progenitor cells.
The SOX18 transgene used with the present invention can comprise any nucleic acid sequence encoding the SOX18 protein. For example, the SOX18 transgene can be obtained by amplifying the SOX18 gene sequence from the genomic locus in human cells or by amplifying SOX18 mRNA from hPSCs differentiated into endothelial and blood cells and converting it into cDNA. Alternatively, genomic DNA or cDNA clones can be obtained commercially (e.g., from Sino Biological, Origene, or IDT). In some embodiments, the transgene comprises SEQ ID NO.:16, a cDNA sequence encoding the human SOX18 protein (having an amino acid sequence set forth in SEQ ID NO: 17).
In some embodiments, the SOX18 transgene further comprises a vector sequence that can be used to drive the expression of the SOX18 transgene within the cells. In these embodiments, the transgene is introduced by into the population of hPSCs by transducing the cells with said vector. As used herein, the term “vector” refers to a nucleic acid molecule capable of propagating another nucleic acid to which it is linked. The term includes the vector as a self-replicating nucleic acid structure as well as the vector incorporated into the genome of a host cell into which it has been introduced. Certain vectors are capable of directing the expression of nucleic acids to which they are operatively linked. Such vectors are referred to herein as “expression vectors”.
Vectors suitable for use with the present invention comprise a nucleotide sequence encoding a SOX18 transgene and a heterogeneous sequence necessary for proper propagation of the vector and expression of the encoded polypeptide. The heterogeneous sequence (i.e., sequence from a different species than the transgene) can comprise a heterologous promoter or heterologous transcriptional regulatory region that allows for expression of the polypeptide. Suitable vectors for the expression of the SOX18 transgene include plasmids and viral vectors. In a preferred embodiment, the vector comprises heterologous sequence that allows the transient and/or Inducible expression of the encoded SOX18 protein.
In some embodiments, the vector includes a transposase system, such as the PiggyBac transposon system (see Examples). The PiggyBac transposon is a TTAA-specific mobile genetic element that efficiently transposes between vectors and chromosomes via a “cut and paste” mechanism. PiggyBac transposase recognizes transposon-specific inverted terminal repeat sequences (ITRs) and moves the intervening contents to a TTAA insertion site in a chromosome or another vector. Thus, inserting a gene of interest between two ITRs in a transposon vector allows one to efficiently insert the gene into a target genome. Other suitable transposase systems for use with the present invention include, for example, Sleeping Beauty.
In other embodiments, the vector is a plasmid, a viral vector, a cosmids, or an artificial chromosome. Suitable plasmids include, for example, E. coli cloning vectors. Many suitable viral vectors are known in the art and include, but are not limited to, an adenovirus vector; an adeno-associated virus vector; a pox virus vector, such as a fowlpox virus vector; an alpha virus vector; a baculoviral vector; a herpes virus vector; a retrovirus vector, such as a lentivirus vector; a Modified Vaccinia virus Ankara vector; a Ross River virus vector; a Sindbis virus vector; a Semliki Forest virus vector; and a Venezuelan Equine Encephalitis virus vector. In one particular embodiment, the vector comprises SEQ ID NO:15.
In some embodiments, the vector is an expression vector that comprises a promoter that drives the expression of the SOX18 transgene, preferably transient or inducible expression of the SOX18 transgene. As used herein, the term “promoter” refers to a DNA regulatory region capable of binding RNA polymerase in a cell and initiating transcription of a coding sequence. Although promoters are most commonly found immediately upstream of a coding sequence, they can also be found downstream of or within the coding sequence. Promoters can be derived in their entirety from a native gene or can be composed of multiple elements, including elements derived from promoters found in nature or elements comprising synthetic DNA sequences. It is understood by those skilled in the art that different promoters can direct the expression of a gene in different tissues or cell types, at different stages of development, or in response to different environmental conditions. Preferably, the promoters used with the present invention are inducible promoters. An “inducible promoter” is a promoter that is activated (i.e., initiates transcription) only in the presence of a particular molecule. Inducible promoters allow tight control the expression of a transgene within cells. Many suitable inducible expression systems are known in the art and include, for example, Tet-On gene expression systems that allow one to induce the expression of a gene by administering tetracycline (Tc) or tetracycline-derivatives like doxycycline (DOX). Suitable Tet-On systems for use with the present invention include, without limitation, Tet-On Advanced and Tet-On 3G. Tet-On systems utilize several promoters, including both minimal promoters (e.g., CMV) flanked by a tetracycline response element (TRE) and engineered Tet-inducible promoters (e.g., TRE2 and TREtight). For instance, in the Examples, the SOX18 transgene is inserted (i.e., via conventional cloning methods) downstream of the doxycycline-inducible TREtight promoter within a vector. This vector was introduced into the hPSCs, allowing the inventors to induce expression of the SOX18 transgene at the desired stage of differentiation by adding doxycycline to the cell culture to activate expression from the TREtight promoter. Those of skill in the art are aware of many additional inducible gene expression systems, including both chemical-inducible and temperature-inducible systems. Other suitable inducible gene expression systems for use with the present invention include, without limitation, the glucocorticoid-responsive mouse mammary tumor virus promoter (MMTVprom), the tamoxifen-responsive hormone-binding domain of the estrogen receptor (ERTAM), the ecdysone-inducible promoter (EcP), heat shock inducible promoters (e.g., Hsp70 or Hsp90- derived promoters), and the T7 promoter/T7 RNA polymerase system (T7P). The SOX18 transgene can be introduced into the hPSCs using any suitable method, for example by transfection or transduction. In one embodiment, the transgene is introduced by transducing the hPSCs with a vector comprising the SOX18 transgene. In another embodiment, the hPSCs are transduced with an exogenous SOX18 modified mRNA (mmRNA). In yet another embodiment, the hPSCs are transduced with the SOX18 protein. Typically, mmRNAs comprise (i) a 5′ synthetic cap for enhanced translation; (ii) modified nucleotides that confer RNAse resistance and an attenuated cellular interferon response, which would otherwise greatly reduce translational efficiency; and (iii) a 3′ poly-A tail.
As provided herein, SOX18 can be enforced in progenitor cells by introduction of an inducible recombinant genetic construct encoding human SOX18 having a nucleotide sequence set forth herein. As used herein, the term “enforced” when used with regard to SOX18 expression in a progenitor cell for NK cells or megakaryocytes produced according to the methods disclosed herein can be understood by the skilled worker to mean that SOX18 expression in the cell is increased over endogenous SOX18 expression in the cell by introduction therein of an exogenous SOX18-encoding construct wherein SOX18 expression is controlled by an inducible promoter. Endogenous SOX18 can be enforced, inter alia, using reagents and methods known in the art, including but not limited to disclosure in U.S. Patent Application Nos. U.S. 2018/0010124 and 2018/0142207, the disclosures of which are expressly incorporated by reference herein. Such techniques and methodologies can comprise enforced expression of SOX18 in said cells.
As used herein, the term “forced expression ” refers to inducing an increase in the level of a protein of interest (e.g., a transcription factor) in a population of host cells, e.g., hPSCs. Forced expression can include one or more of the following in any combination: introducing exogenous nucleic acids encoding the protein of interest (e.g., by viral transduction, plasmid expression vector transfection, or modified mRNA transfection); protein transduction; genomic modification of a host cell, e.g., replacing a promoter to increase the expression of an endogenous (native) gene; and contacting host cells with a small molecule that induces increased expression of an endogenous protein.
Administration of a therapeutically effective amount of NK cells or megakaryocytes provided herein into the recipient subject is generally effected using methods well known in the art, and usually involves directly injecting or otherwise introducing a therapeutically effective dose of NK progenitor cells into the subject using clinical tools known to those skilled in the art (e.g., U.S. Pat. Nos. 6,447,765; 6,383,481; 6,143,292; and 6,326,198). For example, introduction of NK cells or megakaryocytes of the present invention can be injected locally or systemically via intravascular administration, such as intravenous, intramuscular, or intra-arterial administration, intraperitoneal administration, and the like. Cells can be injected into an infusion bag (e.g., Fenwal infusion bag (Fenwal, Inc.)) using sterile syringes or other sterile transfer mechanisms. The cells can then be immediately infused via IV administration over a period of time, such as 15 minutes, into a free flow IV line into the patient. In some embodiments, additional reagents such as buffers or salts are provided to the recipient subject concurrently with the cells.
Various exemplary embodiments of compositions and methods according to this invention are now described in the following non-limiting Examples. The Examples are offered for illustrative purposes only and are not intended to limit the scope of the present invention in any way. Indeed, various modifications of the invention in addition to those shown and described herein will become apparent to those skilled in the art from the foregoing description and the following examples and fall within the scope of the appended claims.
The Examples set forth herein incorporate and rely on certain experimental and preparatory methods and techniques preformed as exemplified herein.
Cell Culture. Wild type H1 and human pluripotent stem cells (hPSCs) were obtained from WiCell (Madison, WI).
Construction of vectors, generation, and validation of iSOX18 hPSC line. A doxycycline (DOX)-inducible SOX18 H1 hESC line was generated using the PiggyBac system disclosed in Park et al., 2018, Curr. Protoc. Stem Cell Biol. 47: e63 and illustrated in
hPSC maintenance and hematopoietic differentiation. hPSCs were maintained and passaged on Matrigel in mTeSR1 media (WiCell). Hematopoietic differentiation was performed on collagen IV (ColIV)-coated plate in chemically defined serum-free medium as previously described as disclosed in Uenishi et al., 2014, Stem Cell Reports 3: 1073-1084. The iSOX18 H1 line from hPSCs (H1 hESC line from WiCell) was maintained and passaged on Matrigel in mTeSR1 media (WiCell). The cell lines were differentiated on a collagen IV (ColIV)-coated plate. Briefly, to initiate differentiation, cells were plated at 5,000 cells/cm2 onto 6 well plates with E8 media and 10 μM Rock inhibitor (Y-27632, Cayman Chemicals). This media was changed the following day to IF9S media with 50 ng/ml FGF2 (PeproTech), 50 ng/ml BMP4 (PeproTech), 15 ng/ml Activin A (PeproTech), and 2 mM LiCl (Sigma), and cells were cultured in hypoxia (5% CO2, 5% O2). On day 2, the media was changed to IF9S media with 50 ng/ml FGF2, 50 ng/ml VEGF (PeproTech), and 2.5 μM TGF-f3 inhibitor (SB-431542, Cayman), and cells were cultured in hypoxia (5% CO2, 5% O2). On days 4 and 6, the media was changed to IF9S media with 50 ng/ml FGF2, 50 ng/ml VEGF, 50 ng/ml TPO (PeproTech), 50 ng/ml IL-6 (PeproTech), 20 ng/ml SCF (PeproTech), and 10 ng/ml IL-3 (PeproTech), and cells were cultured in normoxia (20% CO2, 5% O2).
Isolation and culture of hemogenic endothelium and hematopoietic progenitors. CD31+ cells from day 4 (D4) cultures of iSOX18 cells were isolated by magnetic activated cell sorting (MACS) using CD31 antibodies. In D4 differentiation cultures almost all CD31+ cells co-express VE-cadherin. Selected cells were plated on OP9 or DLL4-0P9 in 10% α-MEM with 10% FBS (Hyclone) with TPO, SCF (50 ng/ml), IL-6 (20 ng/ml), IL-3 and FLT3L (10 ng/ml). Medium was changed on the following day and extra medium was added on the 3rd day of OP9 co-culture. After 5 days in secondary culture, cells were collected and assessed for colony-forming cells (CFCs), T, and NK potential. Hematopoietic precursor cells (HPs) generated from iSOX18 cells were collected at day 8 (D8) of differentiation. Four different subsets of CD34+CD43+ population CD235a/CD41a-CD45− (P1 subset), CD235a/CD41a+CD45− (P2), CD235a/CD41a+CD45+ (P3) and CD235a/CD41a-CD45+ (P4) were isolated using a MA900 cell sorter (Sony Biotechnology) and cultured on OP9-DLL4 in NK cell differentiation conditions.
Hemangioblast (HB)-CFC and hematopoietic CFC assay. HB-CFC were detected as described in Vodyanik et al., 2010, A mesoderm-derived precursor for mesenchymal stem and endothelial cells, Cell Stem Cell 7: 718-729. Hematopoietic CFCs were detected using serum containing H4435 MethoCult (Stem Cell Technologies). HB-CFCs were detected using a semisolid colony-forming serum-free medium (CF-SFM) containing 40% ES-Cult M3120 methylcellulose (2.5% solution in IMDM, Stem Cell Technologies), 25% StemSpan serum-free expansion medium (SFEM, Stem Cell Technologies), 25% human endothelial serum-free medium (ESFM, ThermoFisher), 10% BIT 9500 supplement (Stem Cell Technologies), GlutaMAX (1/100 dilution, ThermoFisher), Ex-Cyte (1/1000 dilution, Millipore), 100 mM MTG, 50 mg/mL ascorbic acid and 20 ng/mL FGF (Peprotech)
Megakaryocyte differentiation. Floating hematopoietic cells from iSOX18 hPSC cultures were collected at D8 of differentiation and cultured in StemSpan serum-free expansion medium (SFEM, Stem Cell Technologies) with 20 ng/ml SCF, TPO, and IL-11 on an ultra-low attachment 6- well plate for 5 days. Fresh media (2 mL) was added every 2 days. All cytokines were purchased from PeproTech.
NK-cell differentiation. For NK cell differentiation, floating hematopoietic cells from D8 primary cultures or day 4+5 secondary OP9/0P9-DLL4-cocultures were cultured in α-MEM (Invitrogen) with 20% FBS (Hyclone), 25 ng/ml SCF, 5 ng/ml FLT3L, IL-3 and IL-7 and 10 ng/ml IL-15 (PeproTech) on OP9-DLL4 for 5 days. Cells were then cultured in the same media without IL-3 for 3-4 weeks. Cells were passaged weekly onto fresh DLL4-0P9 cells and analyzed by flow cytometry for NK cell surface markers after 3-4 weeks.
Functional analysis of NK cells. To assess cytotoxicity, CD56+ cells were isolated using a MA900 cell sorter and incubated with K562-GFP target cells for 4 hours at 37° C., at effector:target (E:T) ratios of 1:1, 2.5:1, and 5:1, in 96-well plates. Cells were collected in FACS buffer and stained using 7-Aminoactinomycin D (7-AAD) and Annexin V (BD). Specific killing was calculated by subtracting spontaneous K562 death (7-AAD+ cells in no effector control). Production of IFNγ and CD107a expression in isolated CD56+ cells was assessed after incubation with Phorbol 12-myristate 13-acetate (PMA) and ionomyocin (1:500) (BioLegend) for 4 hours. Brefeldin A (1:1000; ThermoFisher) was added at the beginning of the stimulation. Cells were washed with FACS buffer and stained with Live/dead violet 540 (TONBO Bioscience) with CD107a antibody (BD). Cells were treated with fixation/permeabilization buffer (eBioscience) and stained for intracellular IFNγ (BD).
T-cell differentiation. For T cell differentiation, floating hematopoietic cells from D8 of primary differentiation cultures or day 4+5 secondary OP9/0P9-DLL4-cocultures were cultured in a-MEM (Invitrogen) with 20% FBS (Hyclone), 10 ng/ml SCF, 5 ng/ml FLT3L and IL-7 (PeproTech) on OP9-DLL4 for 3 weeks. Cells were passaged weekly onto fresh OP9-DLL4 cells. Cells were analyzed by flow cytometry for T cell surface markers after 21 days. All cytokines were purchased from PeproTech.
Flow cytometry and t-distributed stochastic neighbor embedding algorithm (tSNE) analysis. Flow cytometric analysis was performed using antibodies listed in Table 1 with MACSQuant Analyzer 10 (Miltenyi Biotech) and FlowJo software (FlowJo LLC). For tSNE analysis, individual DOX2-8 and No DOX fcs files were imported into FlowJo to exclude doublets, debris, and dead cells. A subset or 11,000 CD43+ cells were selected for each sample and concatenated. To generate a tSNE map, the concatenated data were analyzed with the parameters 30 perplexity, 550 iteration number and 1540 learning rate (Eta). Concatenated cells were divided manually into No DOX or DOX2-8 and cell subsets were defined by the manual gating. First, cells CD34+ or CD34− were gated and then gated into CD235a/CD41ahiCD45−, CD235a/CD41amedCD45−,CD235a−CD41a−CD45−, CD235a/CD41a−CD45+, or CD235a/CD41a+CD45+ cells.
Apoptosis and cell cycle analysis. Apoptosis was detected by flow cytometry using Annexin V (BD). For cell-cycle analysis, D5 cells were incubated in culture medium with bromodeoxyuridine (BrdU) (10 μM, BD Pharmingen) for 2 hours and stained with antibodies. For BrdU detection, the BrdU flow kit with 7 AAD was used and performed per the manufacturer's instructions. Fluorescent reagents used for analysis, cell viability, apoptosis, and proliferation are listed in Table 2.
Real Time Quantitative Polymerase Chain Reaction (qPCR). RNA was extracted from D4 CD31+ cells isolated from control and DOX-treated cultures of iSOX18 of iSOX173 hPSCs using the RNeasy Plus Micro Kit (QIAGEN). RNA was reverse transcribed into cDNA using random hexamer primers (QIAGEN) with SMART MMLV reverse transcriptase (TaKaRa). qPCR was conducted using TB Green Advantage qPCR Premix (TaKaRa). RPL13A was used as the reference gene to normalize the data. Primer sequences are listed in Table 2.
RNA-Seq data processing and analysis. One hundred nanograms of total RNA was used to prepare sequencing libraries following the Ligation Mediated Sequencing (LM-Seq) protocol (see, Gandillet et al., 2009, Blood 114: 4813-422) and quantified with a Qubit fluorometer (Life Technologies). Final cDNA libraries were quantitated with the Quant-iT PicoGreen Assay Kit (ThermoFisher Scientific), multiplexed, loaded at a final concentration of 1 nM or 2.5 nM, and sequenced as single reads on the NextSeq 2000 (Illumina), respectively. RNA-seq reads were aligned by STAR (version 2.5.2b) to the human genome (version hg38) with GENCODE basic gene annotations (version 38). Gene expression levels were quantified by RSEM (version 1.3.0), and differential expression was analyzed by edgeR (version 3.34.1). A differentially expressed gene was required to have at least two-fold changes and an adjusted p-value <0.05. Gene set enrichment analysis was performed by fgsea (version 1.18.0) with KEGG gene sets from the Molecular Signatures Database (version 7.1). RNA-seq data has been deposited to GEO with the accession code GSE195670 and a review token as yfefeuuwtvcfncx.
Western Blot. For Western Blot experiment, iSOX18 hPSCs were cultured with (2 μg/ml) and without DOX for 24 hours and harvested. In a similar manner, total cells from iSOX18 hPSC differentiation cultures with (D2-D5) and without DOX were collected at day 5 of differentiation. The cells were lysed using Pierce IP lysis buffer with Pierce protease inhibitors. For cell lysate analysis, protein levels were quantified using the Pierce BCA Assay kit (Thermo Fisher, Waltham, MA) and normalized to 8μg of total protein (depending on the individual blot) prior to running on pre-cast 4-12% gradient SDS-PAGE gels and subsequent transfer to PVDF membranes using Bio-Rad Trans-Blot Turbo Transfer System. The membrane was blocked with 5% BSA (Fisher Scientific, BP1600-100) and 5% Difco Skim Milk (BD, 232100) in TBST (1%) for human SOX18 antibody (R&D Systems, 1:1000) and anti-GAPDH (Santa Cruz Biotechnology, 1:5000) probing respectively. The membranes were incubated with primary antibodies overnight at 4° C. after blocking with mild agitation. The membranes were blotted with their corresponding HRP-linked secondary antibodies at room temperature for one hour. The antibodies were diluted in 1% BSA and 1% milk in TBST for SOX18 and GAPDH detection respectively. 1% TBST was used to wash the membranes for three times at 5 minutes intervals. Sheep and rabbit HRP-linked secondary antibodies were purchased from R&D Systems and Santa Cruz Biotechnology. Images were collected using Bio-Rad ChemiDoc XRS+.
Statistical analysis. Data were analyzed using GraphPad Prism version 9 (GraphPad Software Inc.) and Microsoft Excel (Microsoft Corporation). Tests for statistical significance are listed with each experiment; these included two-sided Student's t-tests for paired analyses and one-way ANOVAs, and two-way ANOVAs for experiments with multiple comparisons of variables or grouped variables, accompanied by the Tukey and Sidak post-hoc test, as inferred to be most appropriate by the software.
To determine the impact of SOX18 overexpression on hematopoietic development in humans, H1 hESCs carrying doxycycline (DOX)-inducible SOX18-P2A-Venus were generated (
To determine the stages of hematopoietic development sensitive to SOX18 modulation and the optimal duration of SOX18 overexpression to achieve a maximal effect on hematopoietic output, hESC differentiation cultures were treated with DOX at different times and the phenotype and colony-forming cell (CFC) potential of hematopoietic cells collected on day 8 (D8) of differentiation were analyzed (
To visualize the in-depth phenotype of D8 hematopoietic cells from No DOX and DOX2-8 cultures, CD43+-gated cells were analyzed using the t-distributed stochastic neighbor embedding algorithm (tSNE) which showed distinct single cell deposition between No DOX and DOX2-8 (
To determine the impact of SOX18 overexpression on hematopoietic development in humans, H1 hESCs carrying doxycycline (DOX)-inducible SOX18-P2A-Venus (
To determine the stages of hematopoietic development sensitive to SOX18 modulation and the optimal duration of SOX18 overexpression to achieve a maximal effect on hematopoietic output, hESC differentiation cultures were treated with DOX at different time points and the phenotype and CFC potential of hematopoietic cells collected on D8 of differentiation analyzed (
Analysis of CFC potential revealed that SOX18 has the most significant effect on GM- and E-CFCs. This was the most pronounced in DOX2-6 and DOX2-8 cultures (
To evaluate the effect of SOX18 on lymphoid differentiation, cultures were treated with DOX as shown in
To determine stages of hematopoiesis mostly affected by SOX18 overexpression, the effect of DOX treatment on the formation of the hemangioblast (HB) colonies and HE, including arterial HE specification were analyzed. Enforced expression of SOX18 on D2 of differentiation resulted in almost 3-fold increase in the numbers of HB colonies (
To assess the effect of SOX18 on HE, D4 HE generated in No DOX and DOX conditions were isolated and cultured on OP9 or OP9-DLL4 in presence or absence of DOX (
Analysis of T cell potential revealed that HE from DOX2-4 treated cultures demonstrated decreased total T cell output when cultured on OP9 and OP9-DLL4. This effect was more pronounced when DOX treatment was initiated on D4 in coculture of HE with OP9 or OP9− DLL4, or in DOX2-8 treatment cultures (
As shown in
To define changes in transcriptional program induced by enforced SOX18 expression, RNAseq analysis was performed on D4 HE, D8 CD34+CD43+ subsets and NK cells generated from No DOX and DOX-treated cultures (
To determine whether SOX18 overexpression affects proliferation and apoptosis in major cell subsets, gene sets enrichment analysis was performed in GO categories related to “Regulation of Cell Population Proliferation” and “Apoptosis”. The first GO gene set was significantly altered in D4 and D8 P1 subsets and NK cells in DOX+ versus No DOX comparisons, whereas apoptotic genes were mostly affected in D8 P1 subset (
All publications, patents, and patent applications mentioned in this specification are herein incorporated by reference to the same extent as if each individual publication, patent, and patent application was specifically and individually indicated to be incorporated by reference.
While some embodiments have been illustrated and described in detail in the appended drawings and the foregoing description, such illustration and description are to be considered illustrative and not restrictive. Other variations to the disclosed embodiments can be understood and effected in practicing the claims, from a study of the drawings the disclosure, and the appended claims. The mere fact that certain measures or features are recited in mutually different dependent claims does not indicate that the combination of these measures or features cannot be used. Any reference signs in the claims should not be construed as limiting the scope.
This invention was made with government support under HL142665, OD011106 and HL134655 awarded by the National Institutes of Health. The government has certain rights in the invention.
| Number | Date | Country | |
|---|---|---|---|
| 63404508 | Sep 2022 | US |
