Patent Application
20240010989
The present invention relates to a medium for culturing and expanding nephron progenitor cells, a method for culturing and expanding nephron progenitor cells, and a method for producing renal organoids.
Priority is claimed on Japanese Patent Application No. 2021-002203, filed Jan. 8, 2021, the content of which is incorporated herein by reference.
The number of patients in Japan currently suffering from chronic kidney disease (CKD) is estimated at about 13 million, and it is now being called a new national disease. There are few radical treatments for chronic kidney disease, and the number of End-stage renal disease patients requiring dialysis due to progression of the disease exceeds 340,000 in Japan, which is a significant problem not only medically, but also in terms of the economic costs of treatment. Kidney transplantation is one example of a radical treatment for chronic kidney disease including End-stage renal disease, but due to a severe shortage of donor kidneys, the supply is a long way from meeting the demand.
Kidneys are derived from the early embryonic tissue known as the intermediate mesoderm, and in vertebrates, three kidneys comprising the pronephros, the mesonephros and the metanephros are formed from the intermediate mesoderm, whereas in mammals, the metanephros forms the mature kidney. The metanephros is generated by interaction between two tissue types: the tissue known as the mesenchyme that differentiates into the nephrons and stroma of the mature kidney, and the tissue known as the ureteric bud that differentiates into the renal pelvis, the ureter and a portion of the bladder located distally from the collecting ducts of the mature kidney. Moreover, the existence in the metanephric mesenchyme of nephron progenitor cells (NPC) which exhibit pluripotency and differentiate into the glomerulus and a plurality of types of tubular epithelial cells that constitute the nephrons has already been disclosed (Non-Patent Documents 1 and 2).
One method that has been reported for culturing and expanding mouse nephron progenitor cells (mNPC) is a method that uses bone morphogenetic protein (BMP) 7. For example, Non-Patent Document 3 reports that by using a medium (NPSR medium) containing BMP7, fibroblast growth factor (FGF) 2, heparin, Y-27632, CHIR99021, leukemia inhibitory factor (LIF), A 83-01 and LDN193189, mNPC could be grown across a period of one year or longer.
In order to enable cultured and expanded nephron progenitor cells to be utilized in regenerative medicine and the like, it is necessary to retain the characteristics of the nephron progenitor cells such as differentiation potency during the culturing and expansion process. Consequently, the development of a culturing method that enables efficient culturing and expansion of nephron progenitor cells while retaining the characteristics of the nephron progenitor cells would be very desirable.
Accordingly, the present invention has the objects of providing a medium for culturing and expanding nephron progenitor cells that enables culturing and expansion of the nephron progenitor cells with good retention of the differentiation potency, a method for culturing and expanding nephron progenitor cells using the medium, and a method for producing renal organoids from nephron progenitor cells obtained using the culturing and expansion method.
The present invention includes the following aspects.
The present invention is able to provide a medium for culturing and expanding nephron progenitor cells that enables culturing and expansion of the nephron progenitor cells with good retention of the differentiation potency, a method for culturing and expanding nephron progenitor cells using the medium, and a method for producing renal organoids from nephron progenitor cells obtained using the culturing and expansion method.
A first aspect of the present invention is a medium for culturing and expanding nephron progenitor cells. The medium of this aspect contains a GSK-35 inhibitor, a ROCK inhibitor, and at least one fibroblast growth factor selected from the group consisting of FGF9 and FGF20. In one embodiment, the medium of this aspect also contains a JAK inhibitor.
NPC are cells which are capable of differentiation in vitro into organ structures such as glomerulus-like structures or renal tubule-like structures of the kidney. The differentiation potency of nephron progenitor cells into organ structures can be evaluated, for example, using a method disclosed in Osafune K, et al. (2006), Development 133: 151 to 61. SIX2 is known as a characteristics factor for maintenance of the state as a nephron progenitor cell (Cell Stem Cell 3: 169 to 181 (2008)), and examples of the nephron progenitor cells cultured using the method of the present invention include SIX2-positive nephron progenitor cells. For example, pluripotent stem cells having a reporter gene (such as tdTomato) introduced therein under the regulation of a SIX2 promoter (for example, the OSR1-GFP/SIX2-tdTomato reporter human iPS cells described in the following examples) may be cultured, and SIX2-positive nephron progenitor cells can then be isolated by a conventional method known in the technical field (such as a method using a cell sorter) using expression of the reporter gene as a marker. Further, SIX2 expression in nephron progenitor cells can also be confirmed by a gene expression analysis method such as quantitative RT-PCR (Nat Commun 4, 1367 (2013)). In this description, SIX2-positive nephron progenitor cells include cells expressing SIX2 protein, and cells expressing a protein encoded by a gene under the regulation of the SIX2 promoter. Examples of the human SIX2 gene (NCBI Gene ID: 10736) include, but are not limited to, genes having the nucleotide sequence registered under the NCBI accession number: NM_016932.5, whereas examples of the mouse SIX2 gene (NCBI Gene ID: 20472) include, but are not limited to, genes having the nucleotide sequence registered under the NCBI accession number: NM_011380.2. The nephron progenitor cells cultured in the medium of the present aspect of the invention are preferably positive for OSR1, and also positive for HOX11, WT1, SIX2 and SALL1.
There are no particular limitations on the organism that yields the nephron progenitor cells, and any animal having kidneys may be used. The nephron progenitor cells are preferably mammalian-derived cells, and more preferably human-derived cells. In other words, human nephron progenitor cells are preferred.
The nephron progenitor cells may be cells that have been isolated from the metanephric mesenchyme of an organism, or cells that have been differentially induced from pluripotent stem cells (such as ES cells or iPS cells). The nephron progenitor cells cultured and expanded in the medium of the present aspect are preferably cells that have been induced from pluripotent stem cells, and are more preferably cells induced from iPS cells.
The differential induction of nephron progenitor cells from pluripotent stem cells can be conducted using a conventional method. Examples of the method for inducing nephron progenitor cells from pluripotent stem cells include the methods disclosed in International Patent Publication No. 2014/200115, International Patent Publication No. 2017/043666, and International Patent Publication No. 2018/216743 and the like.
Isolation of the nephron progenitor cells, either from a cell population extracted from the metanephric mesenchyme, or from a cell population differentially induced from pluripotent stem cells, may be conducted, for example, using the expression of an aforementioned nephron progenitor cell marker such as OSR1, HOX11, WT1, SIX2 or SALL1 as a marker. Alternatively, the isolation may be conducted using the expression of c-MET or AGTR2 as a marker (International Patent Publication No. 2020/022261).
The nephron progenitor cells cultured and expanded in the medium of the present aspect may be provided as a cell population that also includes other cell types, or may be provided as a cell population of purified nephron progenitor cells. In the case of a cell population containing the nephron progenitor cells and one or more other cell types, the proportion of the nephron progenitor cells, relative to the total cell count (100%) is preferably 30%, at least 40%, at least 50%, at least 60%, at least 70%, at least 80%, or 90% or greater.
The term “culturing and expanding” means culturing that causes growth of the nephron progenitor cells while retaining the characteristics of the nephron progenitor cells. In other words, the cultured and expanded nephron progenitor cells can be differentiated in vitro into organ structures such as glomerulus-like structures or renal tubule-like structures of the kidney. The medium of the present aspect is capable of culturing and expanding nephron progenitor cells while retaining the characteristics of the nephron progenitor cells, even upon repeated subcultures.
The medium of the present aspect of the invention may be a medium prepared by adding a GSK-3β inhibitor, a ROCK inhibitor, and at least one fibroblast growth factor selected from the group consisting of FGF9 and FGF20 to a basal medium used in animal cell culture. Further, the medium may also be a medium prepared by adding not only a GSK-3β inhibitor, a ROCK inhibitor, and at least one fibroblast growth factor selected from the group consisting of FGF9 and FGF20, but also a JAK inhibitor, to a basal medium used in animal cell culture.
There are no particular limitations on the basal medium, and any medium typically used in animal cell culture may be used without any particular restrictions. Examples of the basal medium include, but are not limited to, IMDM, Medium 199, Eagle's Minimum Essential Medium (EMEM), aMEM, Dulbecco's Modified Eagle Medium (DMEM), Ham's F12 (F12) medium, RPMI 1640 medium, Fischer's medium, and mixed media thereof. The medium may contain serum (such as fetal bovine serum (FBS)), or may be serum-free. If necessary, the medium may contain one or more serum replacements such as albumin, transferrin, KnockOut Serum Replacement (KSR), (a serum replacement for ES cell culture) (Invitrogen Corporation), N2 supplement (Invitrogen Corporation), B27 Supplement (Invitrogen Corporation), fatty acids, insulin, collagen precursors, trace elements, 2-mercaptoethanol and 3′-thiolglycerol. Further, the medium may also contain one or more substances such as lipids, amino acids, L-glutamine, GlutaMAX (Invitrogen Corporation), non-essential amino acids (NEAA), vitamins, growth factors, antibiotics, antioxidants, pyruvic acid, buffers, inorganic salts, or equivalents thereof.
The basal medium may be, for example, a medium prepared by adding amino acids, non-essential amino acids, and a serum replacement and the like to a mixed medium of DMEMIF12 (for example, a mixed medium prepared by mixing DMEM:F12 in a ratio of 1:1).
Supplements may also be added to the basal medium as appropriate. Examples of these supplements include AS401 (StemFit for Differentiation, Ajinomoto Healthy Supply Co., Inc.) and B27 (B-27 Supplement, minus vitamin A (Invitrogen Corporation). The basal medium preferably contains 10% by volume of AS401 relative to the total volume of the basal medium. In this description, a medium containing 10% by volume of AS401 relative to the total volume of the medium is sometimes referred to as a medium containing 10% added AS401.
The basal medium may be, for example, a medium containing 10% AS401 added to a mixed medium of DMEM/F12. For example, the basal medium may be a mixed medium of DMEM/F12 to which 10% AS401 and GlutaMAX (Invitrogen Corporation) have been added. DMEM/F12 Glutamax (Thermo Fischer Scientific Inc.) may be used as the mixed medium of DMEM/F12 containing added GlutaMAX. The basal medium may be DMEM/F12 Glutamax containing 10% added AS401. Using a basal medium containing 10% added AS401 improves the growth rate of the nephron progenitor cells, the shape of the cell mass, and the expression of NPC markers (SIX2 and OSR1) and the renal protection factor (VEGFA) and the like.
The medium of the present aspect of the invention contains a GSK-3p inhibitor, a ROCK inhibitor, and at least one fibroblast growth factor selected from the group consisting of FGF9 and FGF20.
The medium of the present aspect contains a GSK-3β inhibitor. The GSK-3β inhibitor is a substance that inhibits the function of GSK (Glycogen Synthase Kinase) 3β, for example, the kinase activity (such as the phosphorylation of β-catenin). Examples of the GSK-3β inhibitor include the indirubin derivative BIO (alternative name: GSK-3β inhibitor IX: 6-bromoindirubin-3′-oxime, the maleimide derivatives SB216763 (3-(2,4-dichlorophenyl)-4-(1-methyl-1H-indol-3-yl)-1H-pyrrole-2,5-dione) and SB415286 (3-[(3-chloro-4-hydroxyphenyl)amino]-4-(2-nitrophenyl)-1H-pyrrole-2,5-dione), the phenyl α-bromomethyl ketone compound GSK-3β inhibitor VII (4-dibromoacetophenone), the cell membrane-permeable phosphorylation peptide L803-mts (alternative name: GSK-3β Peptide Inhibitor; Myr-N-GKEAPPAPPQSpP-NH2), and CHIR99021 (6-[2-[4-(2,4-dichlorophenyl)-5-(4-methyl-1H-imidazol-2-yl)pyrimidin-2-ylamino]ethylamino]-pyridine-3-carbonitrile), and derivatives of these substances. These compounds are available from Stemgent Inc., Calbiochem Corporation, and Biomol GmbH and the like, or may be prepared in-house. Other examples of the GSK-3β inhibitor include antisense nucleic acids, RNA-interference-inducing nucleic acids (such as siRNA) and dominant negative mutants against GSK-3β, and expression vectors or the like of one of these substances.
A single type of the GSK-3β inhibitor may be used alone, or a combination of two or more types may be used. One example of a preferred GSK-3β inhibitor is CHIR99021. The concentration of the GSK-3β inhibitor in the medium may be selected appropriately in accordance with the type of GSK-3β inhibitor used. For example, the GSK-3β inhibitor is preferably used at a concentration in the vicinity of IC50. In the case where the GSK-35 inhibitor is CHIR99021, the concentration of the GSK-3β inhibitor in the medium is, for example, typically within a range from 0.01 to 100 μM, and is preferably from 0.1 to 10 μM, more preferably from 0.5 to 3 μM, and particularly preferably from 0.5 to 1.5 μM.
The medium of the present aspect contains a ROCK inhibitor. The ROCK inhibitor is a substance that inhibits the function of Rho-kinase (ROCK). Examples of the ROCK inhibitor include Y-27632 (for example, see Ishizaki et al., Mol. Pharmacol. 57, 976 to 983 (2000), and Narumiya et al., Methods Enzymol. 325, 273 to 284 (2000), Fasudil/HA1077 (for example, see Uenata et al., Nature 389: 990 to 994 (1997)), H-1152 (for example, see Sasaki et al., Pharmacol. Ther. 93: 225 to 232 (2002)), Wf-536 (for example, see Nakajima et al., Cancer Chemother Pharmacol. 52(4): 319 to 324 (2003)), and derivatives of these substances; as well as antisense nucleic acids, RNA-interference-inducing nucleic acids (such as siRNA) and dominant negative mutants against ROCK, and expression vectors or the like of one of these substances. Other conventional low-molecular weight compounds may also be used as the ROCK inhibitor (for example, see U.S. Patent Publication Nos. 2005/0209261, 2005/0192304, 2004/0014755, 2004/0002508, 2004/0002507, 2003/0125344 and 2003/0087919, and International Patent Publication Nos. 2003/062227, 2003/059913, 2003/062225, 2022/076976 and 2004/039796.
A single type of the ROCK inhibitor may be used alone, or a combination of two or more types may be used. One example of a preferred ROCK inhibitor is Y-27632. The concentration of the ROCK inhibitor in the medium may be selected appropriately in accordance with the type of ROCK inhibitor used. For example, the ROCK inhibitor is preferably used at a concentration in the vicinity of IC50. In the case where the ROCK inhibitor is Y-27632, the concentration of the ROCK inhibitor in the medium is, for example, typically within a range from 0.1 to 100 μM, and is preferably from 1 to 75 μM, and more preferably from 5 to 50 μM.
The medium of the present aspect also contains at least one fibroblast growth factor selected from the group consisting of FGF9 and FGF20.
The medium of the present aspect may contain fibroblast growth factor (FGF) 9. There are no particular limitations on the organism from which the FGF9 is derived. For example, human FGF9 may be used as the FGF9. Examples of the human FGF9 (NCBI Gene ID: 2254) include proteins having the amino acid sequence of the NCBI accession number: NP_002001.1. The FGF9 may also be a fragment or functional variant of the FGF9, provided the activity that promotes the growth of the nephron progenitor cells is retained. A commercially available substance may be used as the FGF9, or a protein purified from cells or a protein produced by gene recombination may be used. Further, FGF20 belongs to the same sub-family as FGF9, and based on the finding that FGF20 exhibits an action that overlaps the action of FGF9 in nascent kidneys in mice (Barak, H. et al. FGF9 and FGF20 Maintain the Stemness of Nephron Progenitors in Mice and Man. Dev. Cell 22, 1191 to 1207 (2012)), it is thought that FGF20 can be used as a substitute for FGF9.
The concentration of FGF9 in the medium is, for example, typically within a range from 1 to 800 ng/ml, and is preferably from 5 to 500 ng/ml, more preferably from 10 to 400 ng/ml, and even more preferably from 100 to 300 ng/ml.
The medium of the present aspect may contain FGF20, either instead of the FGF9, or together with the FGF9. As described above, FGF20 and FGF9 are known to have similar activity in nascent kidneys, and can be mutually interchanged. There are no particular limitations on the organism from which the FGF20 is derived. For example, human FGF20 may be used as the FGF20. Examples of the human FGF20 (NCBI Gene ID: 26281) include proteins having the amino acid sequence of the NCBI accession number: NP_062825.1. The FGF20 may also be a fragment or functional variant of the FGF20, provided the activity that promotes the growth of the nephron progenitor cells is retained. A commercially available substance may be used as the FGF20, or a protein purified from cells or a protein produced by gene recombination may be used.
The concentration of FGF20 in the medium is, for example, typically within a range from 1 to 800 ng/ml, and is preferably from 5 to 500 ng/ml, more preferably from 10 to 400 ng/ml, and even more preferably from 100 to 300 ng/ml.
The medium of the present aspect may contain either one or both of FGF9 and FGF20. In those cases where the medium of the present aspect contains both FGF9 and FGF20, the concentration of the combination of FGF9 and FGF20 is, for example, typically within a range from 1 to 800 ng/ml, and is preferably from 5 to 500 ng/ml, more preferably from 10 to 400 ng/ml, and even more preferably from 100 to 300 ng/ml.
In addition to the components described above, the medium of the present aspect may also contain one or more other components. Examples of these other components include a JAK inhibitor.
JAK Inhibitor
The medium of the present aspect may contain a JAK inhibitor. A JAK inhibitor is a substance that inhibits the activity of one or more enzymes of the Janus kinase family (such as JAK1, JAK2, JAK3 and TYK2). By inhibiting the enzyme activity of the Janus kinase family, the JAK inhibitor inhibits signal transduction of the JAK-STAT system. By including a JAK inhibitor in the medium in addition to the GSK-3β inhibitor, the ROCK inhibitor, and the one or more fibroblast growth factors selected from the group consisting of FGF9 and FGF20, growth of the nephron progenitor cells can be better promoted. There are no particular limitations on the JAK inhibitor, provided it is capable of inhibiting the activity of one or more enzymes of the Janus kinase family. The JAK inhibitor preferably inhibits the enzyme activity of at least one enzyme selected from the group consisting of JAK1, JAK2 and JAK3, and an inhibitor that inhibits the enzyme activity of JAK2 (namely, a JAK2 inhibitor) is particularly preferred.
There are no particular limitations on the JAK3 inhibitor, provided it is capable of inhibiting the activity of JAK3. Examples of the JAK3 inhibitor include, but are not limited to, TCS21311 (CAS number: 1260181-14-3), WHI-P154 (CAS number: 211555-04-3), PF-06651600 (CAS number: 1792180-81-4), FM-381 (CAS number: 2226521-65-7), CP690550 (CAS number: 540737-29-9), 7H-pyrrolo[2,3-d]pyrimidine-5-carboxylic acid, 4-[3-[(2-methyl-1-oxo-2-propen-1-yl)amino]phenyl-, ethyl ester, JAK3 Inhibitor IV (Cas number: 58753-54-1), ZM449829 (CAS number: 4452-06-6), AZD1480 (CAS number: 935666-88-9), and Selective JAK3 Inhibitor 1 (CAS number: 1443235-95-7), as well as derivatives of these substances. Among these, TCS21311 is preferred as the JAK3 inhibitor.
There are no particular limitations on the JAK2 inhibitor, provided it is capable of inhibiting the activity of JAK2. Examples of the JAK2 inhibitor include, but are not limited to, NVP-BSK805 2HCl (CAS number: 1942919-79-0), TG101209 (CAS number: 936091-14-4), TG101348 (CAS number: 936091-26-8), 1,2,3,4,5,6-hexabromocyclohexane (CAS number: 1837-91-8), CEP33779 (CAS number: 1257704-57-6), and NSC33994 (CAS number: 82058-16-0), as well as derivatives of these substances. Among these, TG101348 is preferred as the JAK2 inhibitor.
The JAK inhibitor may be a JAK2/3 inhibitor. A JAK2/3 inhibitor is an inhibitor that inhibits JAK2 and JAK3. Examples of the JAK2/3 inhibitor include, but are not limited to AG490 (CAS number: 133550-30-8), AT9283 (CAS number: 896466-04-9) and LY3009104 (CAS number: 1187594-09-7), as well as derivatives of these substances.
The JAK inhibitor may be a JAK1/2 inhibitor. A JAK1/2 inhibitor is an inhibitor that inhibits JAK1 and JAK2. Examples of the JAK1/2 inhibitor include, but are not limited to CYT387 (CAS number: 1056634-68-4), S-Ruxolitinib (INCB018424) (CAS number: 941685-37-6) and LY2784544 (CAS number: 1229236-86-5), as well as derivatives of these substances.
The JAK inhibitor is not limited to the low-molecular weight compounds described above, and may also be an antisense nucleic acid, RNA-interference-inducing nucleic acids (such as siRNA) or dominant negative mutant against the Janus kinase family (JAK1, JAK2, JAK3 and TYK2), or an expression vector or the like of one of these substances.
A single type of the JAK inhibitor may be used alone, or a combination of two or more types may be used. The JAK inhibitor is preferably a JAK2 inhibitor, and is more preferably TG101348.
The concentration of the JAK inhibitor in the medium of the present aspect may be selected appropriately in accordance with the type of JAK inhibitor used. For example, the JAK inhibitor is preferably used at a concentration in the vicinity of IC50. For example, the JAK inhibitor may be used at a concentration of at least 0.01 nM, at least 0.05 nM, at least 0.1 nM, at least 0.5 nM, or 1 nM or higher. The upper limit for the concentration of the JAK inhibitor is, for example, not more than 100 nM, not more than 50 nM, nor more than 30 nM, not more than 20 nM, not more than 10 nM, or 5 nM or lower. In the case where the JAK inhibitor is TG101348, the concentration of the TG101348 in the medium is, for example, within a range from 0.5 to 50 nM, from 1 to 30 nM, from 1 to 20 nM, from 1 to 10 nM, or from 1 to 5 nM.
The medium of the present aspect of the invention may also contain components other than those described above, provided the effects of the present invention are not impaired. The medium of the present aspect preferably does not contain any signal transduction inhibitors, enzyme inhibitors, cytokines, or growth factors or the like other than those described above.
In one embodiment, the medium of the present aspect contains a GSK-30 inhibitor, a ROCK inhibitor, and at least one fibroblast growth factors selected from the group consisting of FGF9 and FGF20. In one embodiment, the medium of the present invention contains a GSK-3β inhibitor, a ROCK inhibitor, FGF9 and a JAK inhibitor. In one embodiment, the medium of the present aspect contains a GSK-3β inhibitor, a ROCK inhibitor, FGF9 and a JAK2 inhibitor. In one embodiment, the medium of the present aspect contains CHIR99021, Y-27632 and FGF9. In one embodiment, the medium of the present aspect contains CHIR99021, Y-27632, FGF9 and TG101348. The above FGF9 may be substituted with FGF20.
By including the GSK-3β inhibitor, the ROCK inhibitor, and at least one fibroblast growth factors selected from the group consisting of FGF9 and FGF20, the medium of the present aspect is able to produce favorable growth of the nephron progenitor cells while retaining the differentiation potency of the nephron progenitor cells. By also including a JAK inhibitor in addition to the above components, the medium of the present aspect yields even more favorable growth of the nephron progenitor cells.
By using the medium of the present aspect of the invention, nephron progenitor cells can be grown favorably with good retention of the differentiation potency of the nephron progenitor cells, even when repeated subculturing of the nephron progenitor cells is conducted. Accordingly, the medium of the present aspect can be said to be a medium for subculturing nephron progenitor cells. Further, the medium of the present aspect can also be said to be a maintenance medium for nephron progenitor cells.
A second aspect of the present invention is a method for culturing and expanding nephron progenitor cells that includes a step of culturing nephron progenitor cells in the medium of the first aspect described above.
Examples of the nephron progenitor cells cultured in the method of the present aspect include the same cells as those mentioned above in the section entitled “(Nephron Progenitor Cells: NPC)” within the above description of the <Medium for Culturing and Expanding Nephron Progenitor Cells>. The nephron progenitor cells are preferably human nephron progenitor cells. The nephron progenitor cells are preferably cells that have been induced from pluripotent stem cells, and are more preferably cells induced from iPS cells. In one embodiment, the nephron progenitor cells are nephron progenitor cells that have been induced from human iPS cells.
There are no particular limitations on the culturing method used in the method of the present aspect, provided the medium of the first aspect described above is used. The nephron progenitor cells may be cultured under the type of culturing conditions typically used for culturing animal cells. There are no particular limitations on the culturing temperature, provided the nephron progenitor cells are able to be grown, but the temperature is typically within a range from 25 to 40° C., and preferably from 30 to 40° C. One specific example of the culturing temperature is a temperature of about 37° C. The nephron progenitor cells can typically be cultured in a CO2-containing air atmosphere. The CO2 concentration is typically within a range from about 0.3 to 5%, and is preferably from about 2 to 5%. A specific example of the CO2 concentration is about 5%.
The culture may be an adherent culture or a suspension culture, but a suspension culture is preferred.
There are no particular limitations on the culture period, and any arbitrary period may be used. In the method of the present aspect, by using the medium of the first aspect, long-term culturing can be conducted with good retention of the characteristics of the nephron progenitor cells. In the case of long-term culturing, appropriate subculturing is preferred. By conducting repeated subculturing using the medium of the first aspect described above, culturing of nephron progenitor cells can be continued with good retention of the characteristics of the nephron progenitor cells. The subculturing can be conducted by extracting a cell mass of the nephron progenitor cells from the culture solution, and inoculating a fresh medium with the cell mass. During subculturing, a cell dispersion containing enzymes such as a protease, collagenase and DNase may be used to disperse the cell mass prior to inoculation of the fresh medium. There are no particular limitations on the length of the subculture, and for example, a period of about 2 to 10 days, or about 3-7 days may be used. In one embodiment, the method of the present aspect includes subculturing of nephron progenitor cells.
The method for culturing and expanding nephron progenitor cells according to the present aspect may include the steps (A) and (B) described below:
In step (A), the nephron progenitor cells are cultured for 30 to 60 hours in the medium of the first aspect. The culture time in the medium of the first aspect may be about two days. Examples of the culture time in the medium of the first aspect include times within a range from 35 to 55 hours, or from 40 to 50 hours. This culture time represents the time from inoculation of the nephron progenitor cells in the medium of the first aspect.
In step (B), the cells obtained in step (A) are cultured in a medium containing a GSK-3β inhibitor and at least one fibroblast growth factor selected from the group consisting of FGF9 and FGF20, but containing no ROCK inhibitor (hereinafter referred to as a “ROCK inhibitor-free medium”). Examples of the medium used in step (B) include the medium of the first aspect with the ROCK inhibitor removed. The culture of step (B) can be initiated by replacing the medium used in the culture of step (A) with a ROCK inhibitor-free medium. In step (B), medium replacement may be conducted at a frequency of about once every two days. The medium used for medium replacement may be a ROCK inhibitor-free medium. Medium replacement in step (B) may be conducted about 1 to 5 times, about 2 to 4 times, twice, or three times. Because the medium used in step (B) does not contain a ROCK inhibitor, culturing can be conducted more cheaply than cases where a medium containing a ROCK inhibitor is used.
The method of the present aspect may also include a step (C) described below following the above step (B):
The method of the present aspect may also include steps (D) and (E) described below following the above step (C):
In step (D), culturing may simply be conducted for 30 to 60 hours in the medium used for the subculture of step (C). The culture time in step (D) may be about two days. Examples of the culture time in step (D) include times within a range from 35 to 55 hours, or from 40 to 50 hours. This culture time represents the time from the subculture of the nephron progenitor cells.
In step (E), the cells obtained in step (D) are cultured in a ROCK inhibitor-free medium. In step (E), the same ROCK inhibitor-free medium as that used in step (B) may be used. The culturing in step (E) may be conducted in the same manner as that of step (B).
The nephron progenitor cells used in the method of the present aspect may be cells differentially induced from pluripotent stem cells (such as iPS cells). The nephron progenitor cells may be, for example, cells obtained using the differentiation induction method disclosed in International Patent Publication No. 2018/216743.
Further, the nephron progenitor cells used in the method of the present aspect may be, for example, cells obtained using a method including steps (i) to (vi) described below:
In this step, a late posterior epiblast is induced from the pluripotent stem cells. The late posterior epiblast is characterized as cells that are positive for at least one marker among CDX1, OCT4, NANOG and E-CADHERIN (CDH1), and preferably positive for all of these markers. The late posterior epiblast is preferably also negative for EOMES and BRACHYURY.
In step (i), the pluripotent stem cells are separated using any conventional method known in the field, and then preferably cultured by adherent culture. Examples of the method used for separating the pluripotent stem cells include mechanical separation, and separation using a separation solution having protease and collagenase activity (for example, Accutase™ and Accumax™ (Innovative Cell Technologies, Inc.), or a separation solution having only collagenase activity. The separation method is preferably a method in which the cells are dissociated using a separation solution having protease activity and collagenase activity, and then mechanically finely dispersed into single cells. The pluripotent stem cells used in step (i) are preferably colonies cultured to 70% to 80% confluence with respect to the dish being used.
The medium used in step (i) can be prepared by adding FGF2, BMP4, a GSK-3β inhibitor, and retinoic acid or a derivative thereof to a basal medium typically used in the culture of animal cells. The medium used in step (i) may also contain a ROCK inhibitor. In such cases, the medium used in step (i) can be prepared by adding the ROCK inhibitor as well as the components described above to the basal medium. The types of basal media described above may be used as the basal medium, and the basal medium may either contain serum, or be serum-free. If necessary, the basal medium may contain one or more serum replacements, lipids, amino acids, vitamins, growth factors, low-molecular weight compounds, antibiotics, antioxidants, pyruvic acid, buffers, and inorganic salts or the like.
The same types of ROCK inhibitor as those described above may be used as the ROCK inhibitor. An example of a preferred ROCK inhibitor is Y-27632. The concentration of the ROCK inhibitor used in step (i) may be selected appropriately by a person skilled in the art in accordance with the type of ROCK inhibitor used. In the case where the ROCK inhibitor is Y-27632, the concentration of the ROCK inhibitor is, for example, typically within a range from 0.1 to 100 μM, and is preferably from 1 to 75 μM, and more preferably from 5 to 50 μM.
The same types of GSK-3β inhibitor as those described above may be used as the GSK-3β inhibitor. An example of a preferred GSK-3β inhibitor is CHIR99021. The concentration of the GSK-3β inhibitor used in step (i) may be selected appropriately by a person skilled in the art in accordance with the type of GSK-3β inhibitor used. In the case where the GSK-3β inhibitor is CHIR99021, the concentration of the ROCK inhibitor is, for example, typically within a range from 0.01 to 100 μM, and is preferably from 0.1 to 10 μM, more preferably from 0.5 to 3 μM, and particularly preferably from 0.5 to 1.5 μM.
The FGF2 (basic FGF: bFGF) is preferably human FGF2. Examples of the human FGF2 include proteins having the amino acid sequence of the NCBI (National Center for Biotechnology Information) accession number: AB043041.1. The FGF2 may also be a fragment or functional variant of FGF2, provided the differentiation induction activity is retained. A commercially available substance may be used as the FGF2, or a protein purified from cells or a protein produced by gene recombination may be used. The concentration of FGF2 used in this step is, for example, within a range from 1 to 1,000 ng/ml, preferably from 10 to 500 ng/ml, and more preferably from 50 to 250 ng/ml.
The BMP4 is preferably human BMP4. Examples of the human BMP4 include proteins having the amino acid sequence of the NCBI (National Center for Biotechnology Information) accession number: AAH20546.1. The BMP4 may also be a fragment or functional variant of BMP4, provided the differentiation induction activity is retained. A commercially available substance may be used as the BMP4, or a protein purified from cells or a protein produced by gene recombination may be used. The concentration of BMP4 used in this step is, for example, within a range from 0.1 to 100 ng/ml, preferably from 0.5 to 50 ng/ml, and more preferably from 0.5 to 5 ng/ml.
The retinoic acid may be retinoic acid itself, or may be a retinoic acid derivative that retains the differentiation induction potency of naturally occurring retinoic acid. Examples of these retinoic acid derivatives include 3-dehydroretinoic acid, 4-[[(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)carbonyl]amino]-benzoic acid (AM580) (Tamura K, et al., Cell Differ. Dev. 32: 17 to 26 (1990)), 4-[(1E)-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1-propen-1-yl]-benzoic acid (TTNPB) (Strickland S, et al., Cancer Res. 43: 5268 to 5272 (1983)), as well as a compound disclosed in Tanenaga, K. et al., Cancer Res. 40: 914 to 919 (1980), retinol palmitate, retinol, retinal, 3-dehydroretinol, and 3-dehydroretinal. The concentration of the retinoic acid or derivative thereof used in step (i) is, for example, within a range from 1 to 100 nM, preferably from 5 to 50 nM, and more preferably from 5 to 25 nM.
In step (i), there are no particular limitations on the culture temperature, but the temperature is typically about 30 to 40° C., and preferably about 37° C. The culture is conducted in a CO2-containing air atmosphere. The CO2 concentration is typically within a range from about 2 to 5%, and is preferably about 5%. The culture time of step (i) may be any time sufficient to achieve differential induction of a late posterior epiblast, but is typically one to two days, and preferably one day.
(Step (ii))
In this step, a mesodermal-lineage primitive streak is induced from the late posterior epiblast. The mesodermal-lineage primitive streak is characterized as cells that are positive for CDX1 and BRACHYURY. The mesodermal-lineage primitive streak is preferably also negative for OCT4, NANOG, and CDH1.
In step (ii), a cell population obtained in the step (i) described above may be isolated and subjected to adherent culture in a separately prepared culture vessel that has been subjected to a coating treatment, or culture of the cells obtained by adherent culture in step (i) may simply be continued by replacing the medium.
The medium used in step (ii) can be prepared by adding FGF2, a GSK-3β inhibitor and BMP7 to a basal medium typically used in animal cell culture. The types of basal media described above may be used as the basal medium, and the basal medium may either contain serum, or be serum-free. If necessary, the basal medium may contain one or more serum replacements, lipids, amino acids, vitamins, growth factors, low-molecular weight compounds, antibiotics, antioxidants, pyruvic acid, buffers, and inorganic salts or the like.
The same type of FGF2 as that described above may be used. The concentration of the FGF2 used in step (ii) may be within the same range as the concentration described for step (i).
The same types of GSK-3β inhibitor as those described above may be used as the GSK-3β inhibitor. One example of a preferred GSK-3β inhibitor is CHTR99021. The concentration of the GSK-3β inhibitor used in step (ii) may be selected appropriately by a person skilled in the art in accordance with the type of GSK-3β inhibitor used, but is, for example, typically within a range from 0.01 to 100 μM, and is preferably from 0.1 to 10 μM, more preferably from 1 to 7.5 μM, and particularly preferably from 2 to 5 μM. The concentration of the GSK-3β inhibitor used in step (ii) is preferably higher than the concentration in step (i).
The BMP7 is preferably human BMP7. Examples of human BMP7 include proteins having the amino acid sequence of the NCBI (National Center for Biotechnology Information) accession number: NM_001719.2. The BMP7 may also be a fragment or functional variant of BMP7, provided the differentiation induction activity is retained. A commercially available substance may be used as the BMP7, or a protein purified from cells or a protein produced by gene recombination may be used.
The concentration of BMP7 used in step (ii) is, for example, within a range from 0.1 to 100 ng/ml, preferably from 0.5 to 50 ng/ml, and more preferably from 0.5 to 5 ng/ml.
In step (ii), there are no particular limitations on the culture temperature, but the temperature is typically about 30 to 40° C., and preferably about 37° C. The culture is conducted in a CO2-containing air atmosphere. The CO2 concentration is typically within a range from about 2 to 5%, and is preferably about 5%. The culture time of step (ii) may be any time sufficient to achieve differential induction of the mesodermal-lineage primitive streak, but is typically within a range from 10 hours to two days, one to two days, and preferably 0.5 to one day.
(Step (iii))
In this step, a mesodermal-lineage late primitive streak is induced from the mesodermal-lineage primitive streak. The mesodermal-lineage late primitive streak is characterized as cells that are positive for CDX2 and BRACHYURY.
In step (iii), a cell population obtained in the step (ii) described above may be isolated and subjected to adherent culture in a separately prepared culture vessel that has been subjected to a coating treatment, or culture of the cells obtained by adherent culture in step (ii) may simply be continued by replacing the medium.
The medium used in step (iii) can be prepared by adding a GSK-3β inhibitor, BMP7 and a TGFβ inhibitor to a basal medium typically used in animal cell culture. The types of basal media described above may be used as the basal medium, and the basal medium may either contain serum, or be serum-free. If necessary, the basal medium may contain one or more serum replacements, lipids, amino acids, vitamins, growth factors, low-molecular weight compounds, antibiotics, antioxidants, pyruvic acid, buffers, and inorganic salts or the like.
The same types of GSK-3β inhibitor as those described above may be used as the GSK-3β inhibitor. The concentration of the GSK-3β inhibitor used in step (iii) may be within the same range as the concentration described for step (ii). The concentration of the GSK-3β inhibitor is, for example, typically within a range from 0.01 to 100 μM, and is preferably from 0.1 to 10 μM, more preferably from 1 to 7.5 μM, and particularly preferably from 2 to 5 μM.
The same type of BMP7 as that described above may be used. The concentration of the BMP7 used in step (iii) may be within the same range as the concentration described for step (ii).
The TGFβ inhibitor is a substance that inhibits signal transduction that proceeds from binding of TGFβ to a receptor through to SMAD. Examples of the TGFβ inhibitor include substances that inhibit binding to the ALK family, which function as TGFβ receptors, and substances that inhibit phosphorylation of SMAD by the ALK family. Examples of such substances include Lefty-1 (NCBI Accession numbers include mouse: NM_010094, and human: NM_020997), SB431542 and SB202190 (R. K. Lindemann et al., Mol. Cancer, 2003, 2:20), SB505124 (GlaxoSmithKline plc), NPC30345, SD093, SD908 and SD208 (Scios Ltd.), LY2109761, LY364947 and LY580276 (Lilly Research Laboratories), A83-01 (WO 2009146408), and derivatives of these substances. The TGFβ inhibitor may be preferably A83-01.
There are no particular limitations on the concentration of the TGFβ inhibitor used in step (iii), provided it enables inhibition of ALK. In those cases where the TGFβ inhibitor is A83-01, the concentration of the TGFβ inhibitor is, for example, typically within a range from 0.5 to 100 μM, preferably from 1 to 50 μM, and more preferably from 5 to 25 μM.
The medium used in step (iii) does not contain FGF2. Because the mesodermal-lineage late primitive streak is induced even without FGF2, culturing can be conducted more cheaply than methods in which a medium containing FGF2 is used.
In step (iii), there are no particular limitations on the culture temperature, but the temperature is typically about 30 to 40° C., and preferably about 37° C. The culture is conducted in a CO2-containing air atmosphere. The CO2 concentration is typically within a range from about 2 to 5%, and is preferably about 5%. The culture time of step (iii) may be any time sufficient to achieve differential induction of the mesodermal-lineage late primitive streak, but is typically one to three days, and preferably one to two days.
(Step (iv))
In this step, a metanephric-lineage late primitive streak is induced from the mesodermal-lineage late primitive streak. The metanephric-lineage late primitive streak is characterized as cells that are positive for HOX11 and BRACHYURY.
In step (iv), a cell population obtained in the step (iii) described above may be isolated and subjected to adherent culture in a separately prepared culture vessel that has been subjected to a coating treatment, or culture of the cells obtained by adherent culture in step (iii) may simply be continued by replacing the medium.
The medium used in step (iv) can be prepared by adding a FGF2, a GSK-30 inhibitor, activin, and a ROCK inhibitor to a basal medium typically used in animal cell culture. The types of basal media described above may be used as the basal medium, and the basal medium may either contain serum, or be serum-free. If necessary, the basal medium may contain one or more serum replacements, lipids, amino acids, vitamins, growth factors, low-molecular weight compounds, antibiotics, antioxidants, pyruvic acid, buffers, and inorganic salts or the like.
The same types of FGF2 and GSK-3β inhibitor as those described above may be used. The concentrations of FGF2 and the GSK-3β inhibitor used in step (iv) may be within the same ranges as the concentrations described for step (ii). The concentration of the GSK-3β inhibitor used in step (iv) is, for example, typically within a range from 0.01 to 100 μM, and is preferably from 0.1 to 10 μM, more preferably from 1 to 7.5 μM, and particularly preferably from 2 to 5 μM. The concentration of FGF2 used in step (iv) is, for example, typically within a range from 1 to 1,000 ng/ml, preferably 30 ng/ml or higher, and more preferably from 30 to 100 ng/ml.
The activin may be human-derived activin, activin derived from another animal, or a functional variant of one of these activins. The activin may be activin A, activin B, or activin AB. Commercially available products from R&D Systems Inc. or the like may be used as the activin. An example of a preferred activin is activin A. The concentration of the activin used in step (iv) is, for example, typically within a range from 1 to 100 ng/ml, preferably from 5 to 50 ng/ml, and more preferably from 5 to 25 ng/ml.
The same types of ROCK inhibitors as those described above may be used as the ROCK inhibitor. An example of a preferred ROCK inhibitor is Y-27632. The concentration of the ROCK inhibitor used in step (iv) may be selected appropriately by a person skilled in the art in accordance with the type of ROCK inhibitor used. In those cases where the ROCK inhibitor is Y-27632, the concentration of the ROCK inhibitor is, for example, typically within a range from 0.1 to 100 μM, preferably from 1 to 75 μM, and more preferably from 5 to 50 μM.
The medium used in step (iv) may be a medium that does not contain BMP7. By using a medium not containing BMP7, step (iv) can be conducted more cheaply.
In step (iv), there are no particular limitations on the culture temperature, but the temperature is typically about 30 to 40° C., and preferably about 37° C. The culture is conducted in a CO2-containing air atmosphere. The CO2 concentration is typically within a range from about 2 to 5%, and is preferably about 5%. The culture time of step (iv) may be any time sufficient to achieve differential induction of the metanephric-lineage late primitive streak, but is typically one to five days, and preferably three days.
In this step, a late posterior intermediate mesoderm is induced from the metanephric-lineage late primitive streak. The intermediate mesoderm is characterized as cells that are positive for OSR1, HOX11, and WT1.
In step (v), a cell population obtained in the step (iv) described above may be isolated and subjected to adherent culture in a separately prepared culture vessel that has been subjected to a coating treatment, or culture of the cells obtained by adherent culture in step (iv) may simply be continued by replacing the medium.
The medium used in step (v) can be prepared by adding retinoic acid or a derivative thereof to a basal medium typically used in animal cell culture. The medium used in step (v) may also contain a BMP inhibitor. In such cases, the medium used in step (v) can be prepared by adding a BMP inhibitor to the basal medium as well as the above component. The types of basal media described above may be used as the basal medium, and the basal medium may either contain serum, or be serum-free. If necessary, the basal medium may contain one or more serum replacements, lipids, amino acids, vitamins, growth factors, low-molecular weight compounds, antibiotics, antioxidants, pyruvic acid, buffers, and inorganic salts or the like.
A BMP inhibitor is a substance that inhibits the function of BMP. Examples of the BMP inhibitor include protein-based inhibitors such as Chordin, Noggin and Follistatin, Dorsomorphin (namely, 6-[4-(2-piperidin-1-yl-ethoxy)phenyl]-3-pyridin-4-yl-pyrazolo[1,5-a]pyrimidine) and derivatives thereof (P. B. Yu et al. (2007), Circulation, 116:II_60; P. B. Yu et al. (2008), Nat. Chem. Biol., 4: 33 to 41; and J. Hao et al. (2008), PLoS ONE, 3(8): e2904), and LDN193189 (namely, 4-(6-(4-(piperazin-1-yl)phenyl)pyrazolo[1,5-a]pyrimidin-3-yl)quinoline).
An example of a preferred BMP inhibitor is Noggin. In those cases where the BMP inhibitor is Noggin, the concentration of the BMP inhibitor used in step (v) is, for example, typically within a range from 1 to 100 ng/ml, and preferably from 10 to 50 ng/ml.
The medium used in step (v) does not contain FGF9. Because the late posterior intermediate mesoderm is induced even without FGF9, culturing can be conducted more cheaply than methods in which a medium containing FGF9 is used. The medium used in step (v) need not contain FGF20.
In step (v), there are no particular limitations on the culture temperature, but the temperature is typically about 30 to 40° C., and preferably about 37° C. The culture is conducted in a CO2-containing air atmosphere. The CO2 concentration is typically within a range from about 2 to 5%, and is preferably about 5%. The culture time of step (v) may be any time sufficient to achieve differential induction of the late posterior intermediate mesoderm, but is typically one to three days, and preferably two days.
(Step (vi))
In this step, nephron progenitor cells are induced from the late posterior intermediate mesoderm. The nephron progenitor cells are positive for OSR1, and also positive for HOX11, WT1, SIX2 and SALL1.
In step (vi), a cell population obtained in the step (v) described above may be isolated and subjected to adherent culture in a separately prepared culture vessel that has been subjected to a coating treatment, or culture of the cells obtained by adherent culture in step (v) may simply be continued by replacing the medium.
The medium used in step (vi) can be prepared by adding a GSK-3β inhibitor and at least one fibroblast growth factor selected from the group consisting of FGF9 and FGF20 to a basal medium typically used in animal cell culture. The medium used in step (vi) may also contain heparin. In such cases, the medium used in step (vi) can be prepared by adding the heparin as well as the components described above to the basal medium. The types of basal media described above may be used as the basal medium, and the basal medium may either contain serum, or be serum-free. If necessary, the basal medium may contain one or more serum replacements, lipids, amino acids, vitamins, growth factors, low-molecular weight compounds, antibiotics, antioxidants, pyruvic acid, buffers, and inorganic salts or the like.
The heparin is preferably in the form of a salt. Examples of heparin salts include salts with an alkali metal such as lithium, sodium or potassium; salts with an alkaline earth metal such as calcium, barium or magnesium; salts with other metals such as aluminum, zinc, copper or iron; ammonium salts; salts with organic bases; and salts with amino acids. Among the various possibilities, the heparin is preferably an alkali metal salt, and is more preferably a sodium salt.
The concentration of the heparin used in step (vi) is, for example, typically within a range from 0.01 to 100 μg/nl, preferably from 0.05 to 50 μg/nl, and more preferably from 0.1 to 10 μg/ml.
The same types of GSK-3β inhibitor, FGF9 and FGF20 as those described above may be used. The concentration of the GSK-3β inhibitor is, for example, typically within a range from 0.01 to 100 μM, and is preferably from 0.1 to 10 μM, more preferably from 0.5 to 3 μM, and particularly preferably from 0.5 to 1.5 μM. The concentration of the FGF9 or FGF20 (or the total concentration of FGF9 and FGF20) is, for example, typically within a range from 1 to 500 ng/ml, from 10 to 300 ng/ml, or from 50 to 200 ng/ml.
In step (vi), there are no particular limitations on the culture temperature, but the temperature is typically about 30 to 40° C., and preferably about 37° C. The culture is conducted in a CO2-containing air atmosphere. The CO2 concentration is typically within a range from about 2 to 5%, and is preferably about 5%. The culture time of step (vi) may be any time sufficient to achieve differential induction of the nephron progenitor cells, but is typically one to five days, and preferably two days.
The basal medium used in steps (i) to (vi) described above may use the same types of basal media described above in the section entitled “<Medium for Culturing and Expanding Nephron Progenitor Cells>”. For example, a medium prepared by adding B27, AS401, and GlutaMAX-I (Invitrogen Corporation) or the like to a mixed medium of DMEM/F12 may be used as the basal medium. One specific example of the basal medium may be prepared by adding B27 and 10% AS401 or 20% AS401 to DMEM/F12 Glutamax. A medium prepared by adding 10% AS401 to DMEM/F12 Glutamax is preferred.
There are no particular limitations on the culture vessels used in the above steps (i) to (vi). Examples of the culture vessels include 24-well plates, 12-well plates, Petri dishes, culture flasks, bioreactors, and cell culture bags and the like. The use of a culture vessel that enables adherent culture is preferred. The area of the cell adhesion surface (for example, the bottom surface of the culture vessel) of the culture vessel is, for example, typically within a range from 1 to 1,000 cm2. A culture vessel having a cell adhesion surface area of at least 400 cm2 may be used. The area of the cell adhesion surface of the culture vessel is, for example, within a range from 400 to 800 cm2, from 400 to 700 cm2, or from 400 to 600 cm2. In a differentiation induction method including steps (i) to (vi), nephron progenitor cells can be differentially induced even when the type of large-volume couture vessel described above is used. By using a large-volume culture vessel, the cell yield of the nephron progenitor cells can be increased. In steps (i) to (vi), the culture vessel may be changed at the time of medium replacement, or at the time of cell inoculation. For example, a medium-volume culture vessel (for example with a cell adhesion surface area of 50 to 200 cm2) may be used in steps (i) to (iii), with a large-volume culture vessel (for example, with a cell adhesion surface area of 400 cm2 or greater) then being used in steps (iv) to (vi).
Adherent culture means culture conducted in a state where the cells are adhered to a culture substrate, and may mean, for example, culturing in a culture vessel that has been subjected to a coating treatment. The coating agent is preferably an extracellular matrix, and examples include substances such as collagen, proteoglycan, fibronectin, hyaluronic acid, tenascin, entactin, elastin, fibrillin and laminin, and fragments thereof. These extracellular matrices may be used in combination, and for example, may include products prepared from cells such as BD Matrigel (a registered trademark). The extracellular matrix is preferably laminin or a fragment thereof. In the present invention, laminin refers to a protein having a heterotrimer structure having one α-chain, one β-chain, and one γ-chain, and is an extracellular matrix protein in which isoforms exists with different compositions for the subunit chains. Laminin has about 15 types of isoforms in which the heterotrimer is composed of combinations of 5 types of α-chains, 4 types of β-chains, and 3 types of γ-chains. Examples include, but are not limited to, combinations in which the α-chain may be α1, α2, α3, α4 or α5, the β-chain may be β1, β2, β3 or β4, and the γ-chain may be γ1, γ2 or γ3. The laminin is more preferably laminin 511, which is composed of α5, β1 and γ1 (Nat Biotechnol 28, 611-615 (2010)). The laminin may also be a fragment, and there are no particular limitations on the fragment, provided it has integrin-binding activity. For example, the fragment may be an E8 fragment (laminin 511E8), which is a fragment obtained by digestion with elastase (EMBO J., 3:1463 to 1468, 1984, J. Cell Biol., 105: 589 to 598, 1987, and WO 2011/043405). Laminin 511E8 is commercially available, and can be procured, for example, from Nippi, Inc.
The nephron progenitor cells obtained using the steps (i) to (vi) described above can be cultured and expanded by culturing in the medium according to the first aspect. Alternatively, the nephron progenitor cells obtained using steps (i) to (vi) can be cultured and expanded by supplying the cells to a method including steps (A) and (B) described above, and optionally also including steps (C) to (E). In steps (A) to (E), similar culture vessels to those described above for use in steps (i) to (vi) may be used.
Because the method of the present aspect of the invention cultures nephron progenitor cells using the medium of the first aspect, the nephron progenitor cells can be grown favorably with good retention of their differentiation potency. Further, because the differentiation potency of the nephron progenitor cells is retained even upon subculturing, the nephron progenitor cells can be retained for long periods. Nephron progenitor cells cultured and expanded using the method of the present aspect may be administered to subjects having kidney disease, and used for treating the kidney disease. Further, the nephron progenitor cells can be used as a pharmaceutical composition for treating or preventing kidney disease. Furthermore, because nephron progenitor cells cultured using the method of the present aspect retain renal organoid formation capability, they can be used for producing the types of renal organoids described below.
A third aspect of the present invention is a method for producing renal organoids. The method for producing renal organoids according to this aspect includes a step of culturing and expanding nephron progenitor cells using the method of the second aspect described above (a culturing and expansion step), and a step of differentiating the cultured and expanded nephron progenitor cells into renal organoids (a differentiation step).
The culturing and expansion step is conducted using the method of the second aspect described above. This step enables the nephron progenitor cells to be grown favorably to achieve the desired number of cells, with good retention of the differentiation potency.
The differentiation from the nephron progenitor cells into renal organoids may be achieved using a conventional method. For example, a method such as that reported in Nature, 526, 564 to 568 (2015) may be used. For example, a cell mass of the nephron progenitor cells obtained in the preceding culturing and expansion step may be co-cultured with feeder cells such as 3T3-Wnt4 cells, with fetal mouse spinal cord cells, or with fetal mouse kidney cells. Alternatively, a cell mass of the nephron progenitor cells may be subjected to semi-gas phase culture (and preferably gas-liquid culture: Nature, 526, 564 to 568 (2015)) using a basal medium containing a GSK-3β inhibitor. The medium used in the semi-gas phase culture may also contain FGF9 and FGF2 and the like, in addition to the GSK-3β inhibitor. Examples of the basal medium, the GSK-3β inhibitor and the FGF2 include the same substances as those mentioned above. An example of a preferred basal medium is KSR. An example of a preferred GSK-3β inhibitor is CHIR99021. An example of a preferred FGF2 is human FGF2. An example of a preferred FGF9 is human FGF9. Examples of human FGF9 include proteins having the amino acid sequence disclosed in NCBI accession number: NP_002001.1. The FGF9 may also be a fragment or functional variant of FGF9, provided the fragment or variant exhibits differentiation induction activity into renal organoids. A commercially available substance may be used as the FGF9, or a protein purified from cells or a protein produced by gene recombination may be used. In the above description, the FGF9 may be substituted with FGF20. Alternatively, a combination of FGF9 and FGF20 may be used.
The culture conditions in the differentiation step may employ the types of culture conditions typically used in animal cell culture. Although there are no particular limitations on the culture temperature, provided the differential induction into renal organoids can be achieved, the temperature is typically within a range from 25 to 40°, and preferably from 30 to 40° C. One specific example of the culture temperature is about 37° C. The CO2 concentration may be typically set to a value within a range from about 0.3 to 5%, and preferably from about 2 to 5%. A specific example of the CO2 concentration is about 5%.
Renal organoids obtained using the production method of the present aspect of the invention may be administered to subjects having kidney disease, and used for treating the kidney disease. Further, the renal organoids can be used as a pharmaceutical composition for treating or preventing kidney disease.
The production method of the present aspect may also include one or more other steps in addition to the steps described above. An example of another step is a step, conducted prior to the above culturing and expansion step, of inducing nephron progenitor cells from pluripotent stem cells. This induction of nephron progenitor cells from pluripotent stem cells may be conducted using conventional methods.
The present invention also provides a pharmaceutical composition containing either the nephron progenitor cells obtained using the method of the second aspect or the renal organoids obtained using the production method of the third aspect. The present invention also provides a therapeutic agent for kidney disease containing the nephron progenitor cells or the renal organoids. The present invention also provides a method for treating or preventing kidney disease that includes a step of administering a therapeutically effective amount of the nephron progenitor cells or the renal organoids to either a subject having kidney disease or a subject at risk of kidney disease. The present invention also provides a method for producing cells for treating kidney disease that includes a step of culturing nephron progenitor cells in the medium according to the first aspect.
Examples of the method used for administering the nephron progenitor cells to a subject requiring treatment or prevention of kidney disease include: a method in which the nephron progenitor cells are formed into a sheet, and the sheet is attached to a kidney of the subject; a method in which a cell suspension prepared by suspending the nephron progenitor cells in physiological saline or the like is transplanted into a kidney of the subject; a method in which the nephron progenitor cells are subjected to three-dimensional culture (for example, Dev Cell. Sep. 11, 2012; 23(3): 637 to 651), and the resulting cell mass is transplanted directly into a kidney of the subject; and a method in which the nephron progenitor cells are subjected to three-dimensional culture on a scaffold formed from Matrigel or the like, and the resulting cell mass is transplanted into a kidney of the subject. There are no particular limitations on the site of transplantation, provided the site is inside the kidney, but a site beneath the renal capsule is preferred. Examples of the method used for administering the above renal organoids to a subject requiring treatment or prevention of kidney disease include methods in which the renal organoids are transplanted in vivo (for example, intraperitoneally).
There are no particular limitations on the kidney disease that represents the treatment or prevention subject, and examples include acute kidney injury, chronic renal failure, and chronic kidney diseases that have not progressed to chronic renal failure. There are no particular limitations on the number of nephron progenitor cells or the size of the renal organoids that are transplanted, provided they survive the transplant, and these factors may be adjusted appropriately in accordance with factors such as the size of disease site, and the physique, age, and gender and the like of the administration subject.
The present invention is described below in further detail using a series of examples, but the present invention is not limited to the following examples.
All animal experiments were conducted with the approval of the Kyoto University Animal Experiment Committee. NOD.CB17-Prkdcscid/J mice were procured from Charles River Laboratories Japan, Inc. The mice were raised under specific pathogen free (SPF) conditions in an experimental animal facility of the iPS cell research center of Kyoto University. Food and water was freely available to the mice.
<Induction of Nephron Progenitor Cells (hNPC) from Human iPS Cells>
The 4A6 line (derived from 201B7), which is a human iPS cell line derived from normal human subjects, was differentially induced into human iPS cell-derived NPC in a 24-well plate using the method disclosed in International Patent Publication No. 2018/216743, 100 μL of Accumax was then added, and the cells were then left to stand for 30 minutes in an incubator at 37° C. with a CO2 concentration of 5%. After the 30 minutes, the cells were suspended in 900 μL of 10% FBS. The cell count of the suspended cells was measured with a TC20, a quantity of cells required for flow cytometry was transferred to a 1.5 ml tube, and the tube was centrifuged at 200 g for 5 minutes. Following centrifugation, the supernatant was removed, and the cells were suspended in a ratio of 100 μL of 2% FBS per 1.0×106 cells.
<Purification of c-MET-Positive Cells>
Ten μL of human-HGFR/c-MET antibody to which the fluorescent substance APC had been bound (FAB 3582A, R&D Systems Inc.) was added to 100 μL of the 2% FBS suspension of the induced hNPC cells prepared above, and the resultant was left to stand for 30 minutes on ice. After 30 minutes, the sample was centrifuged at 200 g for 5 minutes, the supernatant was removed, the residue was washed with 1 mL of PBS, and the sample was once again centrifuged at 200 g for 5 minutes and the supernatant removed. This operation was conducted twice. The cells obtained following removal of the supernatant were suspended in DAPI that had been diluted 1,000-fold with 2% FBS, and following filtration through a 40 μm filter, flow cytometry was used to extract the c-MET-positive cells.
In this description, hNPC that have not undergone purification of the c-MET-positive cells are referred to as “hNPC (Bulk)”. Further, hNPC that have undergone purification of the c-MET-positive cells are sometimes referred to as “hNPC (c-MET(+))”.
An hNPSR medium, a CFY medium, and a medium prepared by adding either DMSO or DMSO containing a dissolved JAK inhibitor (JAK2 inhibitor: TG101348 (final concentration: 3 nM)) to the CFY medium were used as test media for culturing and expansion.
The composition of the hNPSR medium is shown in Table 1. The hNPSR medium was prepared by adding the reagents shown in Table 1 to the basal medium shown in Table 1. The composition of the CFY medium is shown in Table 2. The CFY medium was prepared by adding the reagents shown in Table 2 to the basal medium shown in Table 2.
The hNPC were suspended in 50 μL of a test medium in sufficient amount to achieve 2.0×104 cells per well, and the suspension was then used to inoculate a low-attachment 96-well plate (Nunc), and following centrifuging at 300 g for 3 minutes, the cells were subjected to a static culture in an incubator at 37° C. and 5% CO2. Six hours after starting the static culture, a cell mass had formed.
Subsequently, 48 hours after the start of the static culture, an additional 100 μL of the same medium as that used at the time of cell inoculation was administered to each well. Then, 48 hours after this additional administration of medium, 100 μL of supernatant was removed from each well, and a further 100 μL of fresh medium was added. Thereafter, the same operations were repeated every 48 hours. Seven days after starting this suspension culture, the cell mass in each well was transferred to a 1.5 ml tube, the supernatant was removed completely, 30 μL of Accumax (Innovative Cell Technologies, Inc.) was added, and the resultant was left to stand for 10 minutes in an incubator at 37° C. and 5% CO2. After 10 minutes, the sample was suspended in 470 μL of 10% FBS, and the cell count was measured with a TC20 (Bio-Rad Laboratories, Inc.).
A cell mass of the human iPS cell-derived NPC (hNPC) cultured in the test medium was transferred to a 1.5 ml tube, the supernatant was removed completely, 30 μL of Accumax (Innovative Cell Technologies, Inc.) was added, and the resultant was left to stand for 10 minutes in an incubator at 37° C. and 5% CO2. After 10 minutes, the sample was suspended in 470 μL of 10% FBS, and the cell count was measured with a TC20 (Bio-Rad Laboratories, Inc.). The human iPS cell-derived NPC were suspended in the test medium and then used to inoculate a low-attachment 96-well plate (Nunc) in an amount of 2.0×104 cells per well. This low-attachment 96-well plate that had been inoculated with the cells was centrifuged at 300 g for 3 minutes, and the cells were then subjected to static culture in an incubator at 37° C. and 5% CO2. Then, 48 hours after starting this static culture, an additional 100 μL of the test medium was administered to each well. Subsequently, 48 hours after this additional administration, the above operations were repeated, with the cell count being measured and a subculture conducted.
A cell mass of hNPC that had been subcultured in the test medium were placed in a Transwell (Corning), and the surrounding medium was removed. Next, the Transwell with the cell mass thereon was set in a culture dish that had been filled with 5% KSR (Kock-out Serum Replacement) (Thermo Fisher Scientific) to which 200 ng/mL of FGF2 and 5 μM of CHIR99021 had been added in advance. After 48 hours, the medium was replaced with 5% KSR containing no added growth factors or low-molecular weight compounds. Thereafter, the medium was replaced every 48 hours with fresh 5% KSR containing no added growth factors or low-molecular weight compounds, and on the 10th day after starting the differentiation culture, the cells were fixed for 3 hours at 4° C. using 4% PFA without removal from the Transwell. Following fixing, the medium was replaced with PBS, and after standing overnight at 4° C., immunostaining was conducted.
Human iPS cells were established which had an OSR1-GFP reporter gene in which a GFP coding region had been introduced at the OSR1 locus, and also had an introduced SIX2-tdTomato reporter gene in which the tdTomato coding region was linked to the SIX2 gene. Expression of OSR1 and SIX2 was confirmed by conducting a culture test using these human iPS cells, and detecting the respective fluorescence from the GFP and tdTomato using a fluorescence microscope.
Bright field images of renal organoids were captured using either a KEYENCE BZ-X700 or a confocal microscope (Zeiss LSM710). Image analysis was performed using Image J version 1.51j8 (National Institutes of Health) (C. A. Schneider, et al., Nat Methods. 9 (2012) 671 to 675.).
<hNPC Administration Experiments>
Cisplatin that had been adjusted to a concentration of 1 mg/mL with physiological saline was injected subcutaneously into 8 to 12-week old male NOD.CB17-Prkdcscid/J mice (hereinafter referred to as “NOD-SCID mice”) at a dose of 21 mg/kg to create a cisplatin-induced acute kidney injury (AKI) model. Twenty four hours after the cisplatin administration, the left kidney was exposed extracorporeally under general anesthesia with isoflurane by making an approximately 1 cm skin incision in the lower left dorsal region of each NOD-SCID mouse, followed by an approximately 1 cm incision in the retroperitoneum. A 24-gauge Surflo indwelling needle was used to puncture the exposed kidney, and an outer tube was secured beneath the renal capsule. The renal capsule and the renal parenchyma were detached by injecting air or physiological saline with a syringe through the outer tube. Subsequently, the outer tube of the 24-gauge Surflo indwelling needle was removed, an hNPC (Bulk) cell mass (equivalent to about 3.0×106 cells) that had been cultured and expanded for one or two passages in the CFY medium) was inserted from the same puncture site into the outer tube of an aspirated 22-gauge Surflo indwelling needle, and the cells were injected slowly into the kidney (cell transplantation). In the saline group, 15 μL of physiological saline was injected beneath the renal capsule instead of the hNPC (Bulk).
Following injection of the cells, the outer tube of the 22-gauge Surflo indwelling needle was removed, and following confirmation that there was no cell outflow or bleeding from the puncture site, the exposed kidney was returned to the retroperitoneum, and the retroperitoneum and skin were sutured with 4-0 blade silk sutures.
Ninety six hours after the cisplatin administration (72 hours after the cell transplantation), 100 to 200 μL of blood was collected from the subocular venous plexus and centrifuged to obtain the serum. Subsequently, using the serum obtained from the centrifugal separation, the serum creatinine (S-Cre) and blood urea nitrogen (BUN) were measured using a Fuji Drychem NX500.
Subcultures of hNPC (Bulk) were conducted using the CFY medium and the hNPSR medium, and the cell growth, expression of NPC markers, and renal organoid formation capability of the cultured cells were ascertained.
<Maintenance Culture of hNPC (Bulk) in CFY Medium>
Subcultures of hNPC (Bulk) were conducted using the hNPSR medium or the CFY medium, and verification was made as to whether the expression of the NPC markers SIX2 and OSR1 was maintained in each subculture.
The results are shown in
<Production of Renal Organoids from hNPC (Bulk) Subcultured in CFY Medium>
Attempts were made to produce renal organoids from hNPC (Bulk) that had been subcultured using either the hNPSR medium or the CFY medium.
The results are shown in
<Cell Growth in Subculture of hNPC (Bulk) using CFY Medium>
Subcultures of hNPC (Bulk) were conducted using media obtained by adding DMSO to either the hNPSR medium or the CFY medium, and the cell counts were measured.
The results are shown in
As illustrated in
A subculture of hNPC (Bulk) was conducted using a medium prepared by adding a JAK inhibitor to the CFY medium, and the cell growth, expression of NPC markers, and renal organoid formation capability of the cultured cells were ascertained.
<Cell Growth Promotion Effect provided by JAK Inhibitor>
Cultures of hNPC (Bulk) were conducted using either a medium prepared by adding DMSO to the CFY medium, or a medium prepared by adding 3 nM of TG101348 (a JAK2 inhibitor) to the CFY medium, and the cell counts were measured.
The results are shown in
<Maintenance Culture of hNPC (Bulk) in CFY Medium with Added JAK Inhibitor>
Subcultures of hNPC (Bulk) were conducted using either a medium prepared by adding DMSO to the CFY medium, or a medium prepared by adding 3 nM TG101348 (a JAK2 inhibitor) to the CFY medium, and verification was made as to whether the expression of the NPC markers OSR1 and SIX2 was maintained in each subculture.
The results are shown in
<Production of Renal Organoids from hNPC (Bulk) Subcultured in CFY Medium with Added JAK Inhibitor>
Subcultures of hNPC (Bulk) were conducted using either a medium prepared by adding DMSO to the CFY medium, or a medium prepared by adding 3 nM TG101348 (a JAK2 inhibitor) to the CFY medium, and attempts were made to produce renal organoids from the cells of passage 2.
The results are shown in
A subculture of hNPC (c-MET(+)) was conducted using a medium prepared by adding a JAK inhibitor to the CFY medium, and the cell growth, expression of NPC markers, and renal organoid formation capability of the cultured cells were ascertained.
<Cell Growth Promotion Effect of JAK Inhibitor in Subculture of hNPC (c-MET(+))>
Subcultures of hNPC (c-MET(+)) were conducted using either a medium prepared by adding DMSO to the CFY medium, or a medium prepared by adding 3 nM TG101348 (a JAK2 inhibitor) to the CFY medium, cell counts were measured, and cumulative cell counts were calculated.
The results are shown in
<Maintenance Culture of hNPC (c-MET(+)) in CFY Medium with Added JAK Inhibitor>
Subcultures of hNPC (c-MET(+)) were conducted using either a medium prepared by adding DMSO to the CFY medium, or a medium prepared by adding 3 nM TG101348 (a JAK2 inhibitor) to the CFY medium, and verification was made as to whether the expression of the NPC markers OSR1 and SIX2 was maintained in each subculture.
The results are shown in
<Production of Renal Organoids from hNPC (c-MET(+)) Subcultured in CFY Medium with added JAK Inhibitor>
Subcultures of hNPC (c-MET(+)) were conducted using either a medium prepared by adding DMSO to the CFY medium, or a medium prepared by adding 3 nM TG101348 (a JAK2 inhibitor) to the CFY medium, and attempts were made to produce renal organoids from the cells of passage 1.
The results are shown in
Cell masses of hNPC (Bulk) that had been cultured and expanded in the CFY medium were transplanted into the renal subcapsule of AKI mice, and the therapeutic effect of hNPC (Bulk) was ascertained.
The transplantation results of the NPC masses from passage 1 and passage 2 are shown in
In Examples 1 to 4 described above, NPC differentially induced by the differentiation induction method A described below were used, based on the method disclosed in International Patent Publication No. 2018/216743.
Using the protocol described below, an investigation was conducted as to whether hNPC was differentially induced from human iPS cells (hiPSC). The hiPSC used were OSR1-GFP/SIX2-tdTomato reporter human iPS cells derived from 201B7.
<Method for Differentially Inducing hNPC from hiPSC (Differentiation Induction Method B)>
Further, with the exception of replacing the 100 ng/ml of FGF2 in step 4 of the above differentiation induction method B (production of a metanephric-lineage late primitive streak: step 4) with any one of 30 ng/ml of FGF2; 30 ng/ml of FGF2 and 0.18 U/ml (1 μg/ml) of heparin; 10 ng/ml of FGF2; 10 ng/ml of FGF2 and 0.18 U/ml (1 μg/ml) of heparin; or 0 ng/ml of FGF2, hNPC were differentially induced from hiPSC using the same procedure as the differentiation induction method B.
For each of these differentially induced hNPC, the results of confirming the differentiation induction efficiency of SIX2-positive cells are illustrated in
The hNPC were differentially induced from hiPSC in accordance with the protocol of the above differentiation induction method B.
Further, with the exceptions of replacing the 100 ng/ml of FGF2 in step 3 of the differentiation induction method B (production of a mesodermal-lineage late primitive streak: step 3) with either 30 ng/ml of FGF2 or 10 ng/ml of FGF2, and also replacing the 100 ng/ml of FGF2 in step 4 of the differentiation induction method B (production of a metanephric-lineage late primitive streak: step 4) with 30 ng/ml of FGF2, hNPC were differentially induced from hiPSC using the same procedure as the differentiation induction method B.
For each of these differentially induced hNPC, the results of confirming the differentiation induction efficiency of SIX2-positive cells are illustrated in
The hNPC were differentially induced from hiPSC in accordance with the protocol of the above differentiation induction method B.
Further, with the exceptions of replacing the 200 ng/ml of FGF9 in step 5 of the differentiation induction method B (production of a late posterior intermediate mesoderm: step 5) with any one of 100 ng/ml of FGF9; 100 ng/ml of FGF9 and 0.18 U/ml (1 μg/ml) of heparin; 25 ng/ml of FGF9; 25 ng/ml of FGF9 and 0.18 U/ml (1 μg/ml) of heparin; 10 ng/ml of FGF9; 10 ng/ml of FGF9 and 0.18 U/ml (1 μg/ml) of heparin; or 0 ng/ml of FGF9, and also replacing the 100 ng/ml of FGF2 in step 4 of the differentiation induction method B (production of a metanephric-lineage late primitive streak: step 4) with 30 ng/ml of FGF2, hNPC were differentially induced from hiPSC using the same procedure as the differentiation induction method B.
For each of these differentially induced hNPC, the results of confirming the differentiation induction efficiency of SIX2-positive cells are illustrated in
The hNPC were differentially induced from hiPSC in accordance with the protocol of the above differentiation induction method B.
Further, with the exceptions of using DMEM/F12 Glutamax supplemented with either 10% or 20% AS401 (StemFit (a registered trademark) for Differentiation, Ajinomoto Healthy Supply Co., Inc.) as the basal medium in steps 2 to 6 of the differentiation induction method B; replacing the 100 ng/ml of FGF2 in step 3 of the differentiation induction method B (production of a mesodermal-lineage late primitive streak: step 3) with 0 ng/ml of FGF2; replacing the 100 ng/ml of FGF 2 in step 4 of the differentiation induction method B (production of a metanephric-lineage late primitive streak: step 4) with 30 ng/ml of FGF2; replacing the 200 ng/ml of FGF9 in step 5 of the differentiation induction method B (production of a late posterior intermediate mesoderm: step 5) with 0 ng/ml of FGF9; and replacing the 200 ng/ml of FGF9 in step 6 of the differentiation induction method B (production of hNPC: step 6) with 100 ng/ml of FGF9 and 0.18 U/ml (1 μg/ml) of heparin, hNPC were differentially induced from hiPSC using the same procedure as the differentiation induction method B.
For each of these differentially induced hNPC, the results of confirming the differentiation induction efficiency of SIX2-positive cells are illustrated in
With the exception of using a clinical hiPSC stock line as the hiPSC, hNPC were differentially induced in the same manner as Example 8 (the differentiation induction method B). In this example, either B27, or DMEM/F12 Glutamax containing 10% added AS401 was used as the basal medium.
For each of these differentially induced hNPC, the results of ascertaining the SIX2 expression are illustrated in
Using the conditions illustrated in
Using the differentiation induction method C (Large), hNPC were differentially induced from hiPSC. DMEM/F12 Glutamax containing 10% added AS401 was used as the basal medium.
The cell yield following stage 6 of the differentiation induction method C (Large) is shown in
In order to compare the effects of additives in the culturing and expansion process, a CFY medium containing 10% added AS401 instead of B27 (CFY medium (−B27, +10% AS401), a CFY medium containing 20% added AS401 instead of B27 (CFY medium (−B27, +20% AS401), and the CFY medium were prepared.
Using the differentiation induction method C (Small), hNPC were differentially induced from hiPSC. DMEM/F12 Glutamax containing 10% added AS401 was used as the basal medium. The hNPC were collected following stage 6, and a low-attachment 96-well plate was used to conduct culturing and expansion in the CFY medium, the CFY medium (−B27, +10% AS401), or the CFY medium (−B27, +20% AS401).
Based on these results, it is thought that the CFY medium (−B27, +10% AS401) is the most suitable for culturing and expanding hNPC.
Using the differentiation induction method C (Small), hNPC were differentially induced from hiPSC. DMEM/F12 Glutamax containing 10% added AS401 was used as the basal medium. The hNPC were collected following stage 6, and a low-attachment 96-well plate was used to conduct culturing and expansion in the CFY medium, the CFY medium (−B27, +10% AS401), or the CFY medium (−B27, +20% AS401). The hNPC on the seventh day of culturing and expansion, equivalent to a cell mass of 3×106 cells was transplanted beneath the renal capsule of an AKI mouse, and the therapeutic effect of the hNPC was ascertained.
The results of measuring the values for the blood urea nitrogen (BUN) and serum creatine (S-Cre) are shown in
Using the differentiation induction method C (Small), hNPC were differentially induced from hiPSC. DMEM/F12 Glutamax containing 10% added AS401 was used as the basal medium. The hNPC were collected following stage 6, and a low-attachment 96-well plate was used to conduct culturing and expansion in either the CFY medium or the CFY medium (−B27, +10% AS401).
The results of confirming gene expression of the cell mass of hNPC on the seventh day of culturing and expansion are illustrated in
In order to ascertain the effect of FGF9 in the CFY medium, a medium was prepared by adding 300 ng/ml of FGF2 to the CFY medium instead of the FGF9 (CFY medium (−FGF9, +FGF2)).
Next, hNPC were differentially induced from hiPSC using the differentiation induction method A. DMEM/F12 Glutamax containing added B27 (B-27 Supplement, minus vitamin A, Invitrogen) was used as the basal medium. The hNPC were collected following stage 6, and a low-attachment 96-well plate was used to conduct culturing and expansion in either the CFY medium, or the CFY medium (−FGF9, +FGF2).
On the seventh day of culturing and expansion, the cell masses were inspected using an optical microscope and a fluorescence microscope, and the forms observed under the optical microscope and the NPC marker (OSR1, SIX2) expressions observed under the fluorescence microscope were compared. The results are shown in
Renal organoids were differentially induced from hNPC that had been cultured and expanded using the CFY medium or the CFY medium (−FGF9, +FGF2).
The results are shown in
In order to ascertain the effect of the ROCK inhibitor (Y-27632) in the CFY medium, a medium (CF medium) was prepared with the ROCK inhibitor excluded from the CFY medium.
Next, hNPC that had been maintained in the CFY medium was subcultured in the CFY medium. Two days after this passage, a medium replacement to either the CFY medium or the CF medium was performed (first medium replacement). Subsequently, two days after the first medium replacement, another medium replacement to either the CFY medium or the CF medium was performed (second medium replacement). Two days after this second medium replacement, a subculture was conducted in the CFY medium. Using this cycle, subculturing was conducted up until passage 3.
Cells were collected at the time of passage, and NPC marker-positive cells (OSR1, SIX2) were analyzed by flow cytometry.
The results are shown in
First, hNPC that had been maintained in the CFY medium was subcultured in the CFY medium. Two days after this passage, a medium replacement to either the CFY medium or the CF medium was performed (first medium replacement). Subsequently, after another two days, another medium replacement to either the CFY medium or the CF medium was performed (second medium replacement). Two days after this second medium replacement, a subculture was conducted in the CFY medium. Using this cycle, subculturing was conducted up until passage 3.
Cells were collected at the time of passage, and the proportions of cells positive for NPC markers (OSR1, SIX2) and cells positive for c-MET (a cell surface antigen protein specifically expressed in NPC) among the living cells not stained by DAPI were analyzed by flow cytometry.
The results are shown in
First, hNPC that had been maintained in the CFY medium was subcultured in the CFY medium. Two days after this passage, a medium replacement to either the CFY medium or the CF medium was performed (first medium replacement). Subsequently, after another two days, another medium replacement to either the CFY medium or the CF medium was performed (second medium replacement). Two days after this second medium replacement, a subculture was conducted in the CFY medium. Using this cycle, subculturing was conducted up until passage 2.
The cell masses following passage 2 were inspected using an optical microscope and a fluorescence microscope, and the forms observed under the optical microscope and the NPC marker (OSR1, SIX2) expressions observed under the fluorescence microscope were compared. The results are shown in
First, hNPC that had been maintained in the CFY medium was subcultured in the CFY medium. Two days after this passage, a medium replacement to either the CFY medium or the CF medium was performed (first medium replacement). Subsequently, after another two days, another medium replacement to either the CFY medium or the CF medium was performed (second medium replacement). Two days after this second medium replacement, a subculture was conducted in the CFY medium. Using this cycle, subculturing was conducted up until passage 1.
The hNPC following passage 1 was differentially induced into renal organoids. The morphology of the renal organoids was observed under an optical microscope. The results are shown in
The present invention is able to provide a medium for culturing and expanding nephron progenitor cells that enables culturing and expansion of the nephron progenitor cells with good retention of the differentiation potency, a method for culturing and expanding NPC using the medium, and a method for producing renal organoids from nephron progenitor cells obtained using the culturing and expansion method. The nephron progenitor cells and renal organoids obtained using the methods of the present invention can be applied to the treatment or prevention of kidney disease.
| Number | Date | Country | Kind |
|---|---|---|---|
| 2021-002203 | Jan 2021 | JP | national |
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/JP2022/000564 | 1/11/2022 | WO |
