hESC-derived Cells Research Articles

Abstract 461: Prospective Isolation of Heart Field Specific Cardiomyocytes from Differentiating Human Embryonic Stem Cells

Cardiovascular disease (CVD) is the leading cause of death worldwide. Human embryonic stem cell (hESC) derived cardiovascular progenitor cells (CPCs) or cardiomyocytes (CMs) represent a promising candidate for cell-based therapies to treat CVD. Following a myocardial infarction there is extensive CM death and damage primarily localized to the left ventricle of the heart, which is predominantly derived from first heart field (FHF) CPCs during development. This is important in future developmental and regenerative therapy studies since heart field specific cardiac cells will be desired. Current hESC differentiation protocols as well as the use of cardiac-specific reporter lines, yield a mixture of cardiac cells without the ability to isolate heart field specific cardiac progenitors and their associated progeny. Here we generated and characterized a FHF specific TBX5- TdTomato/W hESC reporter line to show that TBX5 + cells represent an enriched population of FHF CPCs that can give rise to CMs, endothelial and smooth muscle cells in vitro . Transplantation of hESC-derived TBX5 + and TBX5 - CPCs into the injured left ventricle of mice showed that these cells were able to survive and predominantly gave rise to CMs without functional integration into the host myocardium. Furthermore, RNA-sequencing analysis of hESC-derived cardiac cells at different stages of development suggested that while TBX5 expression leads to an enrichment of FHF- derived CMs, TBX5 - cells also generate cardiac cells that resemble second heart field (SHF) CMs at the transcriptional level. To enable prospective isolation of FHF and SHF CMs we generated a double transgenic hESC reporter line TBX5 TdTomato/W /NKX2-5 eGFP/W . Using immunostaining, qPCR and electrophysiological studies we were able to confirm the isolation of FHF and SHF specific CMs from differentiating hESCs. Finally, we show that using the novel surface marker, CORIN, we can isolate FHF CMs without the use of genetic reporters. Our studies provide valuable information and resources on the production of heart field specific CMs from hESCs for cell-based therapies to treat CVD.

Recent Trends in Research with Human Pluripotent Stem Cells: Impact of Research and Use of Cell Lines in Experimental Research and Clinical Trials.

SummaryThe human pluripotent stem cell (hPSC) research landscape is rapidly evolving. To assess possible novel trends in hPSC usage, we analyzed experimental hPSC research published from 2014 to 2016 and compared our data with those of earlier periods. The number of papers describing experimental work involving hPSCs increased further with clear differences in the scientific impact of publications from different countries. Our results confirm the leading position of US-based hPSC research, although to a lesser degree than observed previously. Our data reveal that research into human induced pluripotent stem cells alone surpassed human embryonic stem cell (hESC) research by 2015 and rapidly grew after that. We also report on continuing and even slightly growing research activities in the hESC field as well as on a generally declining rate of the generation of new hESC lines. An increasing portion of new hESC lines represents disease-specific and clinical-grade cell lines. The previously noted usage of only a few early established hESC lines in the vast majority of scientific work is sustained. We also provide a comprehensive overview on clinical trials on the basis of hPSCs. We find that the vast majority of those trials are based on hESC-derived cell products that were generated from an only limited number of relatively old cell lines.

Ectopic expression of recipient CD47 inhibits mouse macrophage-mediated immune rejection against human stem cell transplants.

Like conventional transplants, immunosuppression is required to facilitate survival and function of human embryonic stem cell (hESC) derivatives after implantation into xenogeneic recipients. We have previously reported that T cells alone are sufficient to reject allogeneic murine ESC derivatives; and strategies that inhibit T-cell activation, including coreceptor and costimulation blockade, prevent hESC derivatives from being rejected. This study aimed to investigate, in addition to T cells, whether macrophages contribute to transplant rejection of hESC xenografts with nonobese diabetic (NOD)/SCID mice that lack functional T and B cells but have macrophages. We show that acute rejection against hESC-derived endothelial cells (hESC-ECs) was mediated, to some degree, by infiltrating macrophages that phagocytosed them. Transgenic expression of murine CD47 on cell surface of hESC-ECs mitigates macrophage-mediated phagocytosis and improves their survival after transplantation. Our results highlight that innate immune cells, such as macrophages, can reject hESC derivatives, raising concern against the use of NOD/SCID as transplant recipients for testing in vivo function of hESC-derived tissues. Augmenting CD47 signaling promotes survival and function of hESC derivatives after xenogeneic transplantation.-Leung, C. S., Li, J., Xu, F., Wong, A. S. L., Lui, K. O. Ectopic expression of recipient CD47 inhibits mouse macrophage-mediated immune rejection against human stem cell transplants.

Promoter interactome of human embryonic stem cell-derived cardiomyocytes connects GWAS regions to cardiac gene networks

Long-range chromosomal interactions bring distal regulatory elements and promoters together to regulate gene expression in biological processes. By performing promoter capture Hi-C (PCHi-C) on human embryonic stem cell-derived cardiomyocytes (hESC-CMs), we show that such promoter interactions are a key mechanism by which enhancers contact their target genes after hESC-CM differentiation from hESCs. We also show that the promoter interactome of hESC-CMs is associated with expression quantitative trait loci (eQTLs) in cardiac left ventricular tissue; captures the dynamic process of genome reorganisation after hESC-CM differentiation; overlaps genome-wide association study (GWAS) regions associated with heart rate; and identifies new candidate genes in such regions. These findings indicate that regulatory elements in hESC-CMs identified by our approach control gene expression involved in ventricular conduction and rhythm of the heart. The study of promoter interactions in other hESC-derived cell types may be of utility in functional investigation of GWAS-associated regions.

Transplantation of Human Embryonic Stem Cell-Derived Retinal Pigment Epithelial Cells in Macular Degeneration

PurposeTransplantation of human embryonic stem cell (hESC)-derived retinal pigment epithelial (RPE) cells offers the potential for benefit in macular degeneration. Previous trials have reported improved visual acuity (VA), but lacked detailed analysis of retinal structure and function in the treated area.DesignPhase 1/2 open-label dose-escalation trial to evaluate safety and potential efficacy (clinicaltrials.gov identifier, NCT01469832).ParticipantsTwelve participants with advanced Stargardt disease (STGD1), the most common cause of macular degeneration in children and young adults.MethodsSubretinal transplantation of up to 200 000 hESC-derived RPE cells with systemic immunosuppressive therapy for 13 weeks.Main Outcome MeasuresThe primary end points were the safety and tolerability of hESC-derived RPE cell administration. We also investigated evidence of the survival of transplanted cells and measured retinal structure and function using microperimetry and spectral-domain OCT.ResultsFocal areas of subretinal hyperpigmentation developed in all participants in a dose-dependent manner in the recipient retina and persisted after withdrawal of systemic immunosuppression. We found no evidence of uncontrolled proliferation or inflammatory responses. Borderline improvements in best-corrected VA in 4 participants either were unsustained or were matched by a similar improvement in the untreated contralateral eye. Microperimetry demonstrated no evidence of benefit at 12 months in the 12 participants. In one instance at the highest dose, localized retinal thinning and reduced sensitivity in the area of hyperpigmentation suggested the potential for harm. Participant-reported quality of life using the 25-item National Eye Institute Visual Function Questionnaire indicated no significant change.ConclusionsSubretinal hyperpigmentation is consistent with the survival of viable transplanted hESC-derived RPE cells, but may reflect released pigment in their absence. The findings demonstrate the value of detailed analysis of spatial correlation of retinal structure and function in determining with appropriate sensitivity the impact of cell transplantation and suggest that intervention in early stage of disease should be approached with caution. Given the slow rate of progressive degeneration at this advanced stage of disease, any protection against further deterioration may be evident only after a more extended period of observation.

Establishment of Insulin-Producing Cells From Human Embryonic Stem Cells Underhypoxic Condition for Cell Based Therapy.

Diabetes mellitus (DM) is a group of diseases characterized by abnormally high levels of glucose in the blood stream. In developing a potential therapy for diabetic patients, pancreatic cells transplantation has drawn great attention. However, the hinder of cell transplantation for diabetes treatment is insufficient sources of insulin-producing cells. Therefore, new cell based therapy need to be developed. In this regard, human embryonic stem cells (hESCs) may serve as good candidates for this based on their capability of differentiation into various cell types. In this study, we designed a new differentiation protocol that can generate hESC-derived insulin-producing cells (hES-DIPCs) in a hypoxic condition. We also emphasized on the induction of definitive endoderm during embryoid bodies (EBs) formation. After induction of hESCs differentiation into insulin-producing cells (IPCs), the cells obtained from the cultures exhibited pancreas-related genes such as Pdx1, Ngn3, Nkx6.1, GLUT2, and insulin. These cells also showed positive for DTZ-stained cellular clusters and contained ability of insulin secretion in a glucose-dependent manner. After achievement to generated functional hES-DIPCs in vitro, some of the hES-DIPCs were then encapsulated named encapsulated hES-DIPCs. The data showed that the encapsulated cells could possess the function of insulin secretion in a time-dependent manner. The hES-DIPCs and encapsulated hES-DIPCs were then separately transplanted into STZ-induced diabetic mice. The findings showed the significant blood glucose levels regulation capacity and declination of IL-1β concentration in all transplanted mice. These results indicated that both hES-DIPCs and encapsulated hES-DIPCs contained the ability to sustain hyperglycemia condition as well as decrease inflammatory cytokine level in vivo. The findings of this study may apply for generation of a large number of hES-DIPCs in vitro. In addition, the implication of this work is therapeutic value in type I diabetes treatment in the future. The application for type II diabetes treatment remain to be investigated.

Sex Differences in Maturation of Human Embryonic Stem Cell-Derived β Cells in Mice.

Pancreatic progenitors derived from human embryonic stem cells (hESCs) are now in clinical trials for insulin replacement in patients with type 1 diabetes. Animal studies indicate that pancreatic progenitor cells can mature into a mixed population of endocrine cells, including glucose-responsive β cells several months after implantion. However, it remains unclear how conditions in the recipient may influence the maturation and ultimately the function of these hESC-derived cells. Here, we investigated the effects of (1) pregnancy on the maturation of human stage 4 (S4) pancreatic progenitor cells and (2) the impact of host sex on both S4 cells and more mature stage 7 (S7) pancreatic endocrine cells implanted under the kidney capsule of immunodeficient SCID-beige mice. Pregnancy led to increased proliferation of endogenous pancreatic β cells, but did not appear to affect proliferation or maturation of S4 cells at midgestation. Interestingly, S4 and S7 cells both acquired glucose-stimulated C-peptide secretion in females before males. Moreover, S4 cells lowered fasting blood glucose levels in females sooner than in males, whereas the responses with S7 cells were similar. These data indicate that the host sex may impact the maturation of hESC-derived cells in vivo and that this effect can be minimized by more advanced differentiation of the cells before implantation.

DNA methylation alterations in iPSC- and hESC-derived neurons: potential implications for neurological disease modeling

BackgroundGenetic predisposition and epigenetic alterations are both considered to contribute to sporadic neurodegenerative diseases (NDDs) such as Parkinson’s disease (PD). Since cell reprogramming and the generation of induced pluripotent stem cells (iPSCs) are themselves associated with major epigenetic remodeling, it remains unclear to what extent iPSC-derived neurons lend themselves to model epigenetic disease-associated changes. A key question to be addressed in this context is whether iPSC-derived neurons exhibit epigenetic signatures typically observed in neurons derived from non-reprogrammed human embryonic stem cells (hESCs).ResultsHere, we compare mature neurons derived from hESC and isogenic human iPSC generated from hESC-derived neural stem cells. Genome-wide 450 K-based DNA methylation and HT12v4 gene array expression analyses were complemented by a deep analysis of selected genes known to be involved in NDD. Our studies show that DNA methylation and gene expression patterns of isogenic hESC- and iPSC-derived neurons are markedly preserved on a genome-wide and single gene level.ConclusionsOverall, iPSC-derived neurons exhibit similar DNA methylation patterns compared to isogenic hESC-derived neurons. Further studies will be required to explore whether the epigenetic patterns observed in iPSC-derived neurons correspond to those detectable in native brain neurons.

Long-Term Efficacy of GMP Grade Xeno-Free hESC-Derived RPE Cells Following Transplantation.

PurposeRetinal pigment epithelium (RPE) dysfunction underlies the retinal degenerative process in age-related macular degeneration (AMD), and thus RPE cell replacement provides an optimal treatment target. We characterized longitudinally the efficacy of RPE cells derived under xeno-free conditions from clinical and xeno-free grade human embryonic stem cells (OpRegen) following transplantation into the subretinal space of Royal College of Surgeons (RCS) rats.MethodsPostnatal (P) day 20 to 25 RCS rats (n = 242) received a single subretinal injection of 25,000 (low)-, 100,000 (mid)-, or 200,000 (high)-dose xeno-free RPE cells. BSS+ (balanced salt solution) (vehicle) and unoperated eyes served as controls. Optomotor tracking (OKT) behavior was used to quantify functional efficacy. Histology and immunohistochemistry were used to evaluate photoreceptor rescue and transplanted cell survival at 60, 100, 150, and 200 days of age.ResultsOKT was rescued in a dose-dependent manner. Outer nuclear layer (ONL) was significantly thicker in cell-treated eyes than controls up to P150. Transplanted RPE cells were identified in both the subretinal space and integrated into the host RPE monolayer in animals of all age groups, and often contained internalized photoreceptor outer segments. No pathology was observed.ConclusionsOpRegen RPE cells survived, rescued visual function, preserved rod and cone photoreceptors long-term in the RCS rat. Thus, these data support the use of OpRegen RPE cells for the treatment of human RPE cell disorders including AMD.Translational RelevanceOur novel xeno-free RPE cells minimize concerns of animal derived contaminants while providing a promising prospective therapy to the diseased retina.

The Immunogenicity and Immune Tolerance of Pluripotent Stem Cell Derivatives.

Human embryonic stem cells (hESCs) can undergo unlimited self-renewal and differentiate into all cell types in human body, and therefore hold great potential for cell therapy of currently incurable diseases including neural degenerative diseases, heart failure, and macular degeneration. This potential is further underscored by the promising safety and efficacy data from the ongoing clinical trials of hESC-based therapy of macular degeneration. However, one main challenge for the clinical application of hESC-based therapy is the allogeneic immune rejection of hESC-derived cells by the recipient. The breakthrough of the technology to generate autologous-induced pluripotent stem cells (iPSCs) by nuclear reprogramming of patient’s somatic cells raised the possibility that autologous iPSC-derived cells can be transplanted into the patients without the concern of immune rejection. However, accumulating data indicate that certain iPSC-derived cells can be immunogenic. In addition, the genomic instability associated with iPSCs raises additional safety concern to use iPSC-derived cells in human cell therapy. In this review, we will discuss the mechanism underlying the immunogenicity of the pluripotent stem cells and recent progress in developing immune tolerance strategies of human pluripotent stem cell (hPSC)-derived allografts. The successful development of safe and effective immune tolerance strategy will greatly facilitate the clinical development of hPSC-based cell therapy.

Transplantation of Human Pancreatic Endoderm Cells Reverses Diabetes Post Transplantation in a Prevascularized Subcutaneous Site.

SummaryBeta-cell replacement therapy is an effective means to restore glucose homeostasis in select humans with autoimmune diabetes. The scarcity of “healthy” human donor pancreata restricts the broader application of this effective curative therapy. “β-Like” cells derived from human embryonic stem cells (hESC), with the capacity to secrete insulin in a glucose-regulated manner, have been developed in vitro, with limitless capacity for expansion. Here we report long-term diabetes correction in mice transplanted with hESC-derived pancreatic endoderm cells (PECs) in a prevascularized subcutaneous site. This advancement mitigates chronic foreign-body response, utilizes a device- and growth factor-free approach, facilitates in vivo differentiation of PECs into glucose-responsive insulin-producing cells, and reliably restores glycemic control. Basal and stimulated human C-peptide secretion was detected throughout the study, which was abolished upon graft removal. Recipient mice demonstrated physiological clearance of glucose in response to metabolic challenge and safely retrieved grafts contained viable glucose regulatory cells.

Transplantation of Human Embryonic Stem Cell-Derived Retinal Cells into the Subretinal Space of a Non-Human Primate

PurposePrevious studies have demonstrated the ability of retinal cells derived from human embryonic stem cells (hESCs) to survive, integrate into the host retina, and mediate light responses in murine mouse models. Our aim is to determine whether these cells can also survive and integrate into the retina of a nonhuman primate, Saimiri sciureus, following transplantation into the subretinal space.MethodshESCs were differentiated toward retinal neuronal fates using our previously published technique and cultured for 60 to 70 days. Differentiated cells were further treated with 20 μM N-[N-(3,5-Difluorophenacetyl)-L-alanyl]-S-phenylglycine t-butyl ester (DAPT) for a period of 5 days immediately prior to subretinal transplantation. Differentiated cells were labeled with a lentivirus expressing GFP. One million cells (10,000 cells/μL) were injected into the submacular space into a squirrel monkey eye, using an ab externo technique.ResultsRetCam imaging demonstrated the presence and survival of human donor cells 3 months after transplantation in the S. sciureus eye. Injected cells consolidated in the temporal macula. GFP+ axonal projections were observed to emanate from the central consolidation of cells at 1 month, with some projecting into the optic nerve by 3 months after transplantation.ConclusionsHuman ES cell-derived retinal neurons injected into the submacular space of a squirrel monkey survive at least 3 months postinjection without immunosuppression. Some donor cells appeared to integrate into the host inner retina, and numerous donor axonal projections were noted throughout, with some projecting into the optic nerve.Translational RelevanceThese data illustrate the feasibility of hESC-derived retinal cell replacement in the nonhuman primate eye.

A Safety Checkpoint to Eliminate Cancer Risk of the Immune Evasive Cells Derived from Human Embryonic Stem Cells

Human embryonic stem cells (hESCs) hold great promise in the regenerative therapy of many currently untreatable human diseases. One of the key bottlenecks is the immune rejection of hESC-derived allografts by the recipient. To overcome this challenge, we have established new approaches to induce immune protection of hESC-derived allografts through the coexpression of immune suppressive molecules CTLA4-Ig and PD-L1. However, this in turn raises a safety concern of cancer risk because these hESC-derived cells can evade immune surveillance. To address this safety concern, we developed a safety checkpoint so that the immune evasive hESC-derived cells in the graft can be effectively eliminated if any cellular transformation is detected. In this context, we knock-in the suicidal gene herpes simplex virus thymidine kinase (HSVTK) into the constitutive HPRT locus of CP hESCs (knock-in hESCs expressing CTLA4-Ig and PD-L1), denoted CPTK hESCs. Employing humanized mice (Hu-mice) reconstituted with human immune system, we demonstrated that the CPTK hESC-derived cells are protected from immune rejection. In addition, CPTK hESC-derived cells can be efficiently eliminated in vitro and in vivo with FDA approved TK-targeting drug ganciclovir. Therefore, this new safety checkpoint improves the feasibility to use the immune evasive hESC-derived cells for regenerative medicine. Stem Cells 2017;35:1154-1161.

Immunosuppression via Loss of IL2rγ Enhances Long-Term Functional Integration of hESC-Derived Photoreceptors in the Mouse Retina

Loss of photoreceptors is a common endpoint in degenerative retinal diseases. Human pluripotent stem cells provide a potential source for photoreceptor replacement, but, even in mouse models, the efficiency and efficacy of transplantation-based repair remains poor. In this study, we examined the degree to which immune rejection contributes to these disappointing outcomes using an immunodeficient IL2 receptor γ (IL2rγ)-null mouse model. Our results show that prevention of cell rejection in the normal and degenerating retinal environment significantly improves long-term survival and integration of hESC-derived donor retinal cells. Transplanted cells are able to differentiate into mature photoreceptors expressing various opsins and can functionally integrate into congenitally blind mice. Our work suggests that even though the retina is often considered immune-privileged, suppression of host immune-mediated cell rejection may well be a useful approach for improving long-term integration of transplanted cells with a view to successful clinical outcomes.

In vivo Evaluation of Human Embryonic Stem Cells Isolated by 57-C11 Monoclonal Antibody.

BackgroundThe normal cells derived from human embryonic stem cells (hESCs) are regarded as substitutes for damaged or dysfunctional adult cells. However, tumorigenicity of hESCs remains a major challenge in clinical application of hESC-derived cell transplantation. Previously, we generated monoclonal antibody (MAb) 57-C11 specific to the surface molecule on undifferentiated hESCs. The aim of this study is to prove whether 57-C11-positive hESCs are pluripotent and tumorigenic in immunodeficient mice.MethodsUndifferentiated hESCs were mixed with retinoic acid (RA)-differentiated hESCs at different ratios prior to 57-C11-mediated separation. To isolate 57-C11-positive hESCs from the mixture, biotinylated 57-C11 and streptavidin-coated magnetic beads were added to the mixture. Unbound 57-C11-negative hESCs were first isolated after applying magnet to the cell mixture, and 57-C11-bound hESCs were then released from the magnetic beads. In order to measure the efficiency of separation, 57-C11-positive or -negative hESCs were counted after isolation. To evaluate the efficiency of teratoma formation in vivo, 57-C11-positive or negative cells were further injected into left and right, respectively, testes of nonobese diabetic/severe combined immunodeficiency (NOD/SCID) mice.ResultsApproximately 77~100% of undifferentiated hESCs were isolated after applying 57-C11-coated magnetic beads to the mixed cell populations. Importantly, teratomas were not observed in NOD/SCID mice after the injection of isolated 57-C11-negative hESCs, whereas teratomas were observed with 57-C11-positive hESCs.Conclusion57-C11-positive hESCs are pluripotent and tumorigenic. The combination of 57-C11 and magnetic beads will be useful to eliminate remaining undifferentiated hESCs for the safe cell transplantation.

Immunogenicity of human embryonic stem cell-derived beta cells

Aims/hypothesisTo overcome the donor shortage in the treatment of advanced type 1 diabetes by islet transplantation, human embryonic stem cells (hESCs) show great potential as an unlimited alternative source of beta cells. hESCs may have immune privileged properties and it is important to determine whether these properties are preserved in hESC-derived cells.MethodsWe comprehensively investigated interactions of both innate and adaptive auto- and allo-immunity with hESC-derived pancreatic progenitor cells and hESC-derived endocrine cells, retrieved after in-vivo differentiation in capsules in the subcutis of mice.ResultsWe found that hESC-derived pancreatic endodermal cells expressed relatively low levels of HLA endorsing protection from specific immune responses. HLA was upregulated when exposed to IFNγ, making these endocrine progenitor cells vulnerable to cytotoxic T cells and alloreactive antibodies. In vivo-differentiated endocrine cells were protected from complement, but expressed more HLA and were targets for alloreactive antibody-dependent cellular cytotoxicity and alloreactive cytotoxic T cells. After HLA compatibility was provided by transduction with HLA-A2, preproinsulin-specific T cells killed insulin-producing cells.Conclusions/interpretationhESC-derived pancreatic progenitors are hypoimmunogenic, while in vivo-differentiated endocrine cells represent mature targets for adaptive immune responses. Our data support the need for immune intervention in transplantation of hESC-derived pancreatic progenitors. Cell-impermeable macro-encapsulation may suffice.

Effects of Pregnancy on Transplanted Pancreatic Beta Cell Progenitors Derived from Human Embryonic Stem CellsImage 7

Human embryonic stem cells (hESCs) are a potential source of transplantable cells for treating patients with diabetes. However, recent findings from our lab suggest that the cell milieu post-transplant can impact the maturation of hESC-derived pancreatic progenitor cells into functional beta cells. During pregnancy, pancreatic beta cell mass transiently expands to accommodate increased metabolic demands of the mother. Here, we examined the impact of pregnancy on the development of hESC-derived progenitor cells following transplantation into immunodeficient mice. Female transplant recipients and controls (no transplant) were housed with breeder males at 4-weeks post-transplant. A group of male mice also received cell transplants as a positive control. The presence of a cell transplant did not affect fertility, body weight gain during pregnancy, pup weight or litter size in female mice. Between 12 to 15 days of gestation, we observed a significant ~5-fold increase in beta cell proliferation (PCNA+/insulin+ cells) within the endogenous mouse pancreas from pregnant compared to non-pregnant mice, but no difference within the hESC-derived grafts. Exposure to pregnancy also did not impact the secretion of human C-peptide from implanted cells at any stage throughout the study. Interestingly, female transplant recipients displayed glucose-responsive human C-peptide secretion beginning at just 13 weeks post-transplant, whereas grafts from male mice were not glucose responsive until 28 weeks. These data suggest that graft maturation may be faster in female transplant recipients compared to males, and this process is unaffected by pregnancy during the early post-transplant period.

Cryopreserved hepatic progenitor cells derived from human embryonic stem cells can arrest progression of liver fibrosis in rats.

Hepatocytes generated from human embryonic stem cells (hESCs) are considered to be an excellent candidate for restoring the liver function deficiencies. We have earlier standardized a three-step differentiation protocol to generate functional hepatocyte-like cells (HLCs) from hESCs, which expressed the major hepatic markers. We have also found that the HLCs remain stable and functional even after extended period of in vitro culture and cryopreservation. In the present study, we have aimed to investigate the therapeutic potential of cryopreserved-thawed hESC-derived hepatic progenitor cells following transplantation in carbon tetrachloride-induced fibrotic rat livers. Significant therapeutic effects, including improved hepatic histology and normal serum biochemistry of hepatic enzymes along with increased survival rate, were observed in the cell transplanted rats. This result is an encouraging indication to develop methods for clinical application of hESC-derived hepatic lineage cells.

Directed differentiation of human embryonic stem cells to corneal endothelial cell-like cells: A transcriptomic analysis

Corneal endothelial cells (CECs) are a monolayer of cells covering the inner-side of cornea, playing a pivotal role in keeping the cornea transparent. Because adult CECs have no proliferative capacity, the loss of CECs during aging or under pathological conditions would lead to corneal edema, eventually leading to the blindness. Clinically, donated CECs have been successfully transplanted to treat the diseases of CEC deficiency; however, the source of CEC donation is very limited. As an alternative cell source for CEC transplantation, CEC-like cells can be obtained via in vitro differentiation of human pluripotent stem cells. In this study, we introduced a modified two-stage differentiation method to convert H9 human embryonic stem cells (hESCs) to neural crest cells (NCCs), then further into CEC-like cells. The CEC-like cells treated with bovine CEC conditional medium morphologically best resembled primary CECs among all the culture conditions. By whole transcriptome analysis, we found that the typical markers of CECs, such as Na+-K+-ATPase, AQP1, Col8a and ZO-1, are highly expressed in hESC-derived CEC-like cells. By comparing RNA transcriptome of hESC-derived CEC-like cells with human primary fetal and adult CECs, we further identified shared molecular markers such as TRIT1, HSPB11, CRY1 that can be used to quality control CEC derivatives from hESCs. Our study paves the way for the quality-control and future application of hESC-derived CECs in the treatment of CEC deficiency disorders.

Functional Blood Progenitor Markers in Developing Human Liver Progenitors.

SummaryIn the early fetal liver, hematopoietic progenitors expand and mature together with hepatoblasts, the liver progenitors of hepatocytes and cholangiocytes. Previous analyses of human fetal livers indicated that both progenitors support each other's lineage maturation and curiously share some cell surface markers including CD34 and CD133. Using the human embryonic stem cell (hESC) system, we demonstrate that virtually all hESC-derived hepatoblast-like cells (Hep cells) transition through a progenitor stage expressing CD34 and CD133 as well as GATA2, an additional hematopoietic marker that has not previously been associated with human hepatoblast development. Dynamic expression patterns for CD34, CD133, and GATA2 in hepatoblasts were validated in human fetal livers collected from the first and second trimesters of gestation. Knockdown experiments demonstrate that each gene also functions to regulate hepatic fate mostly in a cell-autonomous fashion, revealing unprecedented roles of fetal hematopoietic progenitor markers in human liver progenitors.