Multiple factors to assist human-derived induced pluripotent stem cells to efficiently differentiate into midbrain dopaminergic neurons

Midbrain dopaminergic neurons play an important role in the etiology of neurodevelopmental and neurodegenerative diseases.They also represent a potential source of transplanted cells for therapeutic applications.In vitro differentiation of functional midbrain dopaminergic neurons provides an accessible platform to study midbrain neuronal dysfunction and can be used to examine obstacles to dopaminergic neuronal development.Emerging evidence and impressive advances in human induced pluripotent stem cells,with tuned neural induction and differentiation protocols,makes the production of induced pluripotent stem cell-derived dopaminergic neurons feasible.Using SB431542 and dorsomorphin dual inhibitor in an induced pluripotent stem cell-derived neural induction protocol,we obtained multiple subtypes of neurons,including 20%tyrosine hydroxylase-positive dopaminergic neurons.To obtain more dopaminergic neurons,we next added sonic hedgehog(SHH)and fibroblast growth factor 8(FGF8)on day 8 of induction.This increased the proportion of dopaminergic neurons,up to 75%tyrosine hydroxylase-positive neurons,with 15%tyrosine hydroxylase and forkhead box protein A2(FOXA2)co-expressing neurons.We further optimized the induction protocol by applying the small molecule inhibitor,CHIR99021(CHIR).This helped facilitate the generation of midbrain dopaminergic neurons,and we obtained 31-74%midbrain dopaminergic neurons based on tyrosine hydroxylase and FOXA2 staining.Thus,we have established three induction protocols for dopaminergic neurons.Based on tyrosine hydroxylase and FOXA2 immunostaining analysis,the CHIR,SHH,and FGF8 combined protocol produces a much higher proportion of midbrain dopaminergic neurons,which could be an ideal resource for tackling midbrain-related diseases.

Patient-derived induced pluripotent stem cells with a MERTK mutation exhibit cell junction abnormalities and aberrant cellular differentiation potential

BACKGROUND Human induced pluripotent stem cell(hiPSC)technology is a valuable tool for generating patient-specific stem cells,facilitating disease modeling,and invest-igating disease mechanisms.However,iPSCs carrying specific mutations may limit their clinical applications due to certain inherent characteristics.AIM To investigate the impact of MERTK mutations on hiPSCs and determine whether hiPSC-derived extracellular vesicles(EVs)influence anomalous cell junction and differentiation potential.METHODS We employed a non-integrating reprogramming technique to generate peripheral blood-derived hiPSCs with and hiPSCs without a MERTK mutation.Chromo-somal karyotype analysis,flow cytometry,and immunofluorescent staining were utilized for hiPSC identification.Transcriptomics and proteomics were employed to elucidate the expression patterns associated with cell junction abnormalities and cellular differentiation potential.Additionally,EVs were isolated from the supernatant,and their RNA and protein cargos were examined to investigate the involvement of hiPSC-derived EVs in stem cell junction and differentiation.RESULTS The generated hiPSCs,both with and without a MERTK mutation,exhibited normal karyotype and expressed pluripotency markers;however,hiPSCs with a MERTK mutation demonstrated anomalous adhesion capability and differentiation potential,as confirmed by transcriptomic and proteomic profiling.Furthermore,hiPSC-derived EVs were involved in various biological processes,including cell junction and differentiation.CONCLUSION HiPSCs with a MERTK mutation displayed altered junction characteristics and aberrant differentiation potential.Furthermore,hiPSC-derived EVs played a regulatory role in various biological processes,including cell junction and differentiation.

Small extracellular vesicles secreted by induced pluripotent stem cell-derived mesenchymal stem cells improve postoperative cognitive dysfunction in mice with diabetes

Postoperative cognitive dysfunction(POCD)is a common surgical complication.Diabetes mellitus(DM)increases risk of developing POCD after surgery.DM patients with POCD seriously threaten the quality of patients’life,however,the intrinsic mechanism is unclear,and the effective treatment is deficiency.Previous studies have demonstrated neuronal loss and reduced neurogenesis in the hippocampus in mouse models of POCD.In this study,we constructed a mouse model of DM by intraperitoneal injection of streptozotocin,and then induced postoperative cognitive dysfunction by transient bilateral common carotid artery occlusion.We found that mouse models of DM-POCD exhibited the most serious cognitive impairment,as well as the most hippocampal neural stem cells(H-NSCs)loss and neurogenesis decline.Subsequently,we hypothesized that small extracellular vesicles secreted by induced pluripotent stem cell-derived mesenchymal stem cells(iMSC-sEVs)might promote neurogenesis and restore cognitive function in patients with DM-POCD.iMSC-sEVs were administered via the tail vein beginning on day 2 after surgery,and then once every 3 days for 1 month thereafter.Our results showed that iMSC-sEVs treatment significantly recovered compromised proliferation and neuronal-differentiation capacity in H-NSCs,and reversed cognitive impairment in mouse models of DM-POCD.Furthermore,miRNA sequencing and qPCR showed miR-21-5p and miR-486-5p were the highest expression in iMSC-sEVs.We found iMSC-sEVs mainly transferred miR-21-5p and miR-486-5p to promote H-NSCs proliferation and neurogenesis.As miR-21-5p was demonstrated to directly targete Epha4 and CDKN2C,while miR-486-5p can inhibit FoxO1 in NSCs.We then demonstrated iMSC-sEVs can transfer miR-21-5p and miR-486-5p to inhibit EphA4,CDKN2C,and FoxO1 expression in H-NSCs.Collectively,these results indicate significant H-NSC loss and neurogenesis reduction lead to DM-POCD,the application of iMSC-sEVs may represent a novel cell-free therapeutic tool for diabetic patients with postoperative cognitive dysfunction.

Transplantation of human induced pluripotent stem cell derived keratinocytes accelerates deep second-degree burn wound healing

BACKGROUND Current evidence shows that human induced pluripotent stem cells(hiPSCs)can effectively differentiate into keratinocytes(KCs),but its effect on skin burn healing has not been reported.AIM To observe the effects of hiPSCs-derived KCs transplantation on skin burn healing in mice and to preliminarily reveal the underlying mechanisms.METHODS An analysis of differentially expressed genes in burn wounds based on GEO datasets GSE140926,and GSE27186 was established.A differentiation medium containing retinoic acid and bone morphogenetic protein 4 was applied to induce hiPSCs to differentiate into KCs.The expression of KCs marker proteins was detected using immunofluorescence staining.A model of a C57BL/6 mouse with deep cutaneous second-degree burn was created,and then phosphate buffered saline(PBS),hiPSCs-KCs,or hiPSCs-KCs with knockdown of COL7A1 were injected around the wound surface.The wound healing,re-epithelialization,engraftment of hiPSCs-KCs into wounds,proinflammatory factor level,and the NF-κB pathway proteins were assessed by hematoxylin-eosin staining,carboxifluorescein diacetate succinimidyl ester(CFSE)fluorescence staining,enzyme linked immunosorbent assay,and Western blotting on days 3,7,and 14 after the injection,respectively.Moreover,the effects of COL7A1 knockdown on the proliferation and migration of hiPSCs-KCs were confirmed by immunohistochemistry,EdU,Transwell,and damage repair assays.RESULTS HiPSCs-KCs could express the hallmark proteins of KCs.COL7A1 was down-regulated in burn wound tissues and highly expressed in hiPSCs-KCs.Transplantation of hiPSCs-KCs into mice with burn wounds resulted in a significant decrease in wound area,an increase in wound re-epithelialization,a decrease in proinflammatory factors content,and an inhibition of NF-κB pathway activation compared to the PBS group.The in vitro assay showed that COL7A1 knockdown could rescue the inhibition of hiPSCs-KCs proliferation and migration,providing further evidence that COL7A1 speeds up burn wound healing by limiting cell proliferation and migration.CONCLUSION In deep,second-degree burn wounds,COL7A1 can promote KC proliferation and migration while also suppressing the inflammatory response.

Current overview of induced pluripotent stem cell-based blood-brain barrier-on-a-chip

BACKGROUND Induced pluripotent stem cells(iPSCs)show great ability to differentiate into any tissue,making them attractive candidates for pathophysiological investigations.The rise of organ-on-a-chip technology in the past century has introduced a novel way to make in vitro cell cultures that more closely resemble their in vivo environments,both structural and functionally.The literature still lacks consensus on the best conditions to mimic the blood-brain barrier(BBB)for drug screening and other personalized therapies.The development of models based on BBB-on-achip using iPSCs is promising and is a potential alternative to the use of animals in research.AIM To analyze the literature for BBB models on-a-chip involving iPSCs,describe the microdevices,the BBB in vitro construction,and applications.METHODS We searched for original articles indexed in PubMed and Scopus that used iPSCs to mimic the BBB and its microenvironment in microfluidic devices.Thirty articles were identified,wherein only 14 articles were finally selected according to the inclusion and exclusion criteria.Data compiled from the selected articles were organized into four topics:(1)Microfluidic devices design and fabrication;(2)characteristics of the iPSCs used in the BBB model and their differentiation conditions;(3)BBB-on-a-chip reconstruction process;and(4)applications of BBB microfluidic three-dimensional models using iPSCs.RESULTS This study showed that BBB models with iPSCs in microdevices are quite novel in scientific research.Important technological advances in this area regarding the use of commercial BBB-on-a-chip were identified in the most recent articles by different research groups.Conventional polydimethylsiloxane was the most used material to fabricate in-house chips(57%),whereas few studies(14.3%)adopted polymethylmethacrylate.Half the models were constructed using a porous membrane made of diverse materials to separate the channels.iPSC sources were divergent among the studies,but the main line used was IMR90-C4 from human fetal lung fibroblast(41.2%).The cells were differentiated through diverse and complex processes either to endothelial or neural cells,wherein only one study promoted differentiation inside the chip.The construction process of the BBB-on-a-chip involved previous coating mostly with fibronectin/collagen Ⅳ(39.3%),followed by cell seeding in single cultures(36%)or co-cultures(64%)under controlled conditions,aimed at developing an in vitro BBB that mimics the human BBB for future applications.CONCLUSION This review evidenced technological advances in the construction of BBB models using iPSCs.Nonetheless,a definitive BBB-on-a-chip has not yet been achieved,hindering the applicability of the models.

Methods to produce induced pluripotent stem cell-derived mesenchymal stem cells: Mesenchymal stem cells from induced pluripotent stem cells

Mesenchymal stem cells(MSCs)have received significant attention in recent years due to their large potential for cell therapy.Indeed,they secrete a wide variety of immunomodulatory factors of interest for the treatment of immune-related disorders and inflammatory diseases.MSCs can be extracted from multiple tissues of the human body.However,several factors may restrict their use for clinical applications:the requirement of invasive procedures for their isolation,their limited numbers,and their heterogeneity according to the tissue of origin or donor.In addition,MSCs often present early signs of replicative senescence limiting their expansion in vitro,and their therapeutic capacity in vivo.Due to the clinical potential of MSCs,a considerable number of methods to differentiate induced pluripotent stem cells(iPSCs)into MSCs have emerged.iPSCs represent a new reliable,unlimited source to generate MSCs(MSCs derived from iPSC,iMSCs)from homogeneous and well-characterized cell lines,which would relieve many of the above mentioned technical and biological limitations.Additionally,the use of iPSCs prevents some of the ethical concerns surrounding the use of human embryonic stem cells.In this review,we analyze the main current protocols used to differentiate human iPSCs into MSCs,which we classify into five different categories:MSC Switch,Embryoid Body Formation,Specific Differentiation,Pathway Inhibitor,and Platelet Lysate.We also evaluate common and method-specific culture components and provide a list of positive and negative markers for MSC characterization.Further guidance on material requirements to produce iMSCs with these methods and on the phenotypic features of the iMSCs obtained is added.The information may help researchers identify protocol options to design and/or refine standardized procedures for large-scale production of iMSCs fitting clinical demands.

Genetic Correction and Hepatic Differentiation of Hemophilia B-specific Human Induced Pluripotent Stem Cells

Objective To genetically correct a disease-causing point mutation in human induced pluripotent stem cells （iPSCs） derived from a hemophilia B patient. Methods First, the disease-causing mutation was detected by sequencing the encoding area of human coagulation factor IX （F IX） gene. Genomic DNA was extracted from the iPSCs, and the primers were designed to amplify the eight exons of F IX. Next, the point mutation in those iPSCs was genetically corrected using CRISPR/Cas9 technology in the presence of a 129-nucleotide homologous repair template that contained two synonymous mutations. Then, top 8 potential off-target sites were subsequently analyzed using Sanger sequencing. Finally, the corrected clones were differentiated into hepatocyte-like cells, and the secretion of F IX was validated by immunocytochemistry and ELISA assay.Results The cell line bore a missense mutation in the 6th coding exon （c.676 C〉T） of F IX gene. Correction of the point mutation was achieved via CRISPR/Cas9 technology in situ with a high efficacy at about 22% （10/45） and no off-target effects detected in the corrected iPSC clones. F IX secretion, which was further visualized by immunocytochemistry and quantified by ELISA in vitro, reached about 6 ng/ml on day 21 of differentiation procedure. Conclusions Mutations in human disease-specific iPSCs could be precisely corrected by CRISPR/Cas9 technology, and corrected cells still maintained hepatic differentiation capability. Our findings might throw a light on iPSC-based personalized therapies in the clinical application, especially for hemophilia B.

Efficient generation of hepatocyte-like cells from human induced pluripotent stem cells

Human induced pluripotent stem （iPS） cells are similar to embryonic stem （ES） cells, and can proliferate intensively and differentiate into a variety of cell types. However, the hepatic differentiation of human iPS cells has not yet been reported. In this report, human iPS cells were induced to differentiate into hepatic cells by a stepwise protocol. The expression of liver cell markers and liver-related functions of the human iPS cell-derived cells were monitored and compared with that of differentiated human ES cells and primary human hepatocytes. Approximately 60% of the differentiated human iPS cells at day 7 expressed hepatic markers alpha fetoprotein and Alb. The differentiated cells at day 21 exhibited liver cell functions including albumin Asecretion, glycogen synthesis, urea production and inducible cytochrome P450 activity. The expression of hepatic markers and fiver-related functions of the iPS cellderived hepatic ceils were comparable to that of the human ES cell-derived hepatic cells. These results show that human iPS cells, which are similar to human ES cells, can be efficiently induced to differentiate into hepatocyte-like cells.

Generation of male germ cells from induced pluripotent stem cells （iPS cells）： an in vitro and in vivo study

Recent studies have reported that induced pluripotent stem （iPS） cells from mice and humans can differentiate into primordial germ cells. However, whether iPS cells are capable of producing male germ cells is not known. The objective of this study was to investigate the differentiation potential of mouse iPS cells into spermatogonial stem cells and late-stage male germ cells. We used an approach that combines in vitrodifferentiation and in vivotransplantation. Embryoid bodies （EBs） were obtained from iPS cells using leukaemia inhibitor factor （LIF）-free medium. Quantitative PCR revealed a decrease in Oct4 expression and an increase in StraSand Vasa mRNA in the EBs derived from iPS cells, iPS cell-derived EBs were induced by retinoic acid to differentiate into spermatogonial stem cells （SSCs）, as evidenced by their expression of VASA, as well as CDH1 and GFRal, which are markers of SSCs. Furthermore, these germ cells derived from iPS cells were transplanted into recipient testes of mice that had been pre-treated with busulfan. Notably, iPS cell-derived SSCs were able to differentiate into male germ cells ranging from spermatogonia to round spermatids, as shown by VASA and SCP3 expression. This study demonstrates that iPS cells have the potential to differentiate into late-stage male germ cells. The derivation of male germ cells from iPS cells has potential applications in the treatment of male infertility and provides a model for uncovering the molecular mechanisms underlying male germ cell development.

Induced pluripotent stem cell technology for spinal cord injury: a promising alternative therapy

Spinal cord injury has long been a prominent challenge in the trauma repair process. Spinal cord injury is a research hotspot by virtue of its difficulty to treat and its escalating morbidity. Furthermore, spinal cord injury has a long period of disease progression and leads to complications that exert a lot of mental and economic pressure on patients. There are currently a large number of therapeutic strategies for treating spinal cord injury, which range from pharmacological and surgical methods to cell therapy and rehabilitation training. All of these strategies have positive effects in the course of spinal cord injury treatment. This review mainly discusses the problems regarding stem cell therapy for spinal cord injury, including the characteristics and action modes of all relevant cell types. Induced pluripotent stem cells, which represent a special kind of stem cell population, have gained impetus in cell therapy development because of a range of advantages. Induced pluripotent stem cells can be developed into the precursor cells of each neural cell type at the site of spinal cord injury, and have great potential for application in spinal cord injury therapy.

Induced Pluripotent Stem Cell-derived Mesenchymal Stem Cell Seeding on Biofunctionalized Calcium Phosphate Cements

Induced pluripotent stem ceils （iPSCs） have great potential due to their proliferation and differentiation capability. The objectives of this study were to generate iPSC-derived mesenchymal stem cells （iPSC-MSCs）, and investigate iPSC-MSC proliferation and osteogenic differentiation on calcium phosphate cement （CPC） containing biofunctional agents for the first time. Human iPSCs were derived from marrow CD34＋ cells which were reprogrammed by a single episomal vector, iPSCs were cultured to form embryoid bodies （EBs）, and MSCs migrated out of EBs. Five biofunctional agents were incorporated into CPC： RGD （Arg-Gly-Asp） peptides, fibronectin （Fn）, fibronectin-like engineered polymer protein （FEPP）, extracellular matrix Geltrex, and platelet concentrate, iPSC-MSCs were seeded on five biofunctionalized CPCs： CPC-RGD, CPC-Fn, CPC- FEPP, CPC-Geltrex, and CPC-Platelets. iPSC-MSCs on biofunctional CPCs had enhanced proliferation, actin fiber expression, osteogenic differentiation and mineralization, compared to control. Cell proliferation was greatly increased on biofunctional CPCs. iPSC-MSCs underwent osteogenic differentiation with increased alkaline phosphatase, Runx2 and coUagen-I expressions. Mineral synthesis by iPSC-MSCs on CPC-Platelets was 3-fold that of CPC control. In conclusion, iPSCs showed high potential for bone engineering, iPSC- MSCs on biofunctionalized CPCs had cell proliferation and bone mineralization that were much better than traditional CPC. iPSC-MSC-CPC constructs are promising to promote bone regeneration in craniofacial/ orthopedic repairs.

Inducing human induced pluripotent stem cell differentiation through embryoid bodies:A practical and stable approach

Human induced pluripotent stem cells(hiPSCs)are invaluable resources for producing high-quality differentiated cells in unlimited quantities for both basic research and clinical use.They are particularly useful for studying human disease mechanisms in vitro by making it possible to circumvent the ethical issues of human embryonic stem cell research.However,significant limitations exist when using conventional flat culturing methods especially concerning cell expansion,differentiation efficiency,stability maintenance and multicellular 3D structure establishment,differentiation prediction.Embryoid bodies(EBs),the multicellular aggregates spontaneously generated from iPSCs in the suspension system,might help to address these issues.Due to the unique microenvironment and cell communication in EB structure that a 2D culture system cannot achieve,EBs have been widely applied in hiPSC-derived differentiation and show significant advantages especially in scaling up culturing,differentiation efficiency enhancement,ex vivo simulation,and organoid establishment.EBs can potentially also be used in early prediction of iPSC differentiation capability.To improve the stability and feasibility of EB-mediated differentiation and generate high quality EBs,critical factors including iPSC pluripotency maintenance,generation of uniform morphology using micro-pattern 3D culture systems,proper cellular density inoculation,and EB size control are discussed on the basis of both published data and our own laboratory experiences.Collectively,the production of a large quantity of homogeneous EBs with high quality is important for the stability and feasibility of many PSCs related studies.

Hepatitis B virus infection modeling using multi-cellular organoids derived from human induced pluripotent stem cells

Chronic infection with hepatitis B virus(HBV)remains a global health concern despite the availability of vaccines.To date,the development of effective treatments has been severely hampered by the lack of reliable,reproducible,and scalable in vitro modeling systems that precisely recapitulate the virus life cycle and represent virus-host interactions.With the progressive understanding of liver organogenesis mechanisms,the development of human induced pluripotent stem cell(iPSC)-derived hepatic sources and stromal cellular compositions provides novel strategies for personalized modeling and treatment of liver disease.Further,advancements in three-dimensional culture of self-organized liver-like organoids considerably promote in vitro modeling of intact human liver tissue,in terms of both hepatic function and other physiological characteristics.Combined with our experiences in the investigation of HBV infections using liver organoids,we have summarized the advances in modeling reported thus far and discussed the limitations and ongoing challenges in the application of liver organoids,particularly those with multi-cellular components derived from human iPSCs.This review provides general guidelines for establishing clinical-grade iPSC-derived multi-cellular organoids in modeling personalized hepatitis virus infection and other liver diseases,as well as drug testing and transplantation therapy.

Current Developments in the Stable Production of Human Induced Pluripotent Stem Cells

Induced pluripotent stem cells(iPSCs)are considered to be ideal and promising cell sources for various applications such as regenerative medicine and drug screening.However,effective mass production systems for the stable supply of desired numbers of iPSCs are yet to be developed.This review introduces the various approaches that are currently available for stable iPSC production.We start by discussing the limiting factors to be controlled during iPSC culture,such as nutrient supply,waste removal,and oxygen availability.We then introduce recent investigations on iPSC culture systems based on adhesion,suspension,and scaffolds.We also discuss the downstream processes that follow the culture process,such as filling and freezing processes,which limit the production scale due to decreased cell viability during suspension in cryopreservation medium.Finally,we summarize the possibility of the stable mass production of iPSCs and highlight the limitations that remain to be overcome.We suggest that multidisciplinary investigations are essential to understand the different factors that influence cell growth and quality in order to obtain an optimal and stable iPSC mass production system.

Enrichment of retinal ganglion and Müller glia progenitors from retinal organoids derived from human induced pluripotent stem cells-possibilities and current limitations

BACKGROUND Retinal organoids serve as excellent human-specific disease models for conditions affecting otherwise inaccessible retinal tissue from patients.They permit the isolation of key cell types affected in various eye diseases including retinal ganglion cells(RGCs)and Müller glia.AIM To refine human-induced pluripotent stem cells(hiPSCs)differentiated into threedimensional(3D)retinal organoids to generate sufficient numbers of RGCs and Müller glia progenitors for downstream analyses.METHODS In this study we described,evaluated,and refined methods with which to generate Müller glia and RGC progenitors,isolated them via magnetic-activated cell sorting,and assessed their lineage stability after prolonged 2D culture.Putative progenitor populations were characterized via quantitative PCR and immunocytochemistry,and the ultrastructural composition of retinal organoid cells was investigated.RESULTS Our study confirms the feasibility of generating marker-characterized Müller glia and RGC progenitors within retinal organoids.Such retinal organoids can be dissociated and the Müller glia and RGC progenitor-like cells isolated via magnetic-activated cell sorting and propagated as monolayers.CONCLUSION Enrichment of Müller glia and RGC progenitors from retinal organoids is a feasible method with which to study cell type-specific disease phenotypes and to potentially generate specific retinal populations for cell replacement therapies.

Future of liver transplantation: Non-human primates for patient-specific organs from induced pluripotent stem cells

Strategies to fill the huge gap in supply versus demand of human organs include bioartificial organs, growing humanized organs in animals, cell therapy, and implantable bioengineered constructs. Reproducing the complex relations between different cell types, generation of adequate vasculature, and immunological complications are road blocks in generation of bioengineered organs, while immunological complications limit the use of humanized organs produced in animals. Recent developments in induced pluripotent stem cell (iPSC) biology offer a possibility of generating human, patient-specific organs in non-human primates (NHP) using patient-derived iPSC and NHP-derived iPSC lacking the critical developmental genes for the organ of interest complementing a NHP tetraploid embryo. The organ derived in this way will have the same human leukocyte antigen (HLA) profile as the patient. This approach can be curative in genetic disorders as this offers the possibility of gene manipulation and correction of the patient's genome at the iPSC stage before tetraploid complementation. The process of generation of patient-specific organs such as the liver in this way has the great advantage of making use of the natural signaling cascades in the natural milieu probably resulting in organs of great quality for transplantation. However, the inexorable scientific developments in this direction involve several social issues and hence we need to educate and prepare society in advance to accept the revolutionary consequences, good, bad and ugly.

The combination of induced pluripotent stem cells and bioscaffolds holds promise for spinal cord regeneration

Spinal cord injuries（SCIs） are debilitating conditions for which no effective treatment currently exists. The damage of neural tissue causes disruption of neural tracts and neuron loss in the spinal cord. Stem cell replacement offers a solution for SCI treatment by providing a source of therapeutic cells for neural function restoration. Induced pluripotent stem cells（i PSCs） have been investigated as a potential type of stem cell for such therapies. Transplantation of i PSCs has been shown to be effective in restoring function after SCIs in animal models while they circumvent ethical and immunological concerns produced by other stem cell types. Another approach for the treatment of SCI involves the graft of a bioscaffold at the site of injury to create a microenvironment that enhances cellular viability and guides the growing axons. Studies suggest that a combination of these two treatment methods could have a synergistic effect on functional recovery post-neural injury. While much progress has been made, more research is needed before clinical trials are possible. This review highlights recent advancements using i PSCs and bioscaffolds for treatment of SCI.

Mucosal-associated invariant T cells from induced pluripotent stem cells:A novel approach for modeling human diseases

Mice have frequently been used to model human diseases involving immune dysregulation such as autoimmune and inflammatory diseases.These models help elucidatethe mechanisms underlying the disease and in the development of novel therapies.However,if mice are deficient in certain cells and/or effectors associated with human diseases,how can their functions be investigated in this species?Mucosal-associated invariant T(MAIT)cells,a novel innate-like T cell family member,are a good example.MAIT cells are abundant in humans but scarce in laboratory mice.MAIT cells harbor an invariant T cell receptor and recognize nonpeptidic antigens vitamin B2metabolites from bacteria and yeasts.Recent studies have shown that MAIT cells play a pivotal role in human diseases such as bacterial infections and autoimmune and inflammatory diseases.MAIT cells possess granulysin,a human-specific effector molecule,but granulysin and its homologue are absent in mice.Furthermore,MAIT cells show poor proliferation in vitro.To overcome these problems and further our knowledge of MAIT cells,we have established a method to expand MAIT cells via induced pluripotent stem cells(iP SCs).In this review,we describe recent advances in the field of MAIT cell research and our approach for human disease modeling with iP SCderived MAIT cells.

Cardiotrophin-1 promotes cardiomyocyte differentiation from mouse induced pluripotent stem cells via JAK2/STAT3/Pim-1 signaling pathway

Background The induced pluripotent stem cell （iPSC） has shown great potential in cellular therapy of myocardial infarction （MI）, while its application is hampered by the low efficiency of cardiomyocyte differentiation. The present study was designed to investigate the effects of cardiotrophin-1 （CT-1） on cardiomyocyte differentiation from mouse induced pluripotent stem cells （miPSCs） and the underlying mechanisms involved. Methods The optimal treatment condition for cardiomyocyte differentiation from miPSCs was established with ideal concentration （10 ng/mL） and duration （from day 3 to day 14） of CT-1 administration. Up-regulated expression of cardiac specific genes that accounted for embryonic cardiogenesis was observed by quantitative RT-PCR. Elevated amount of a-myosin heavy chain （ct-MHC） and cardiac troponin I （cTn I） positive cells were detected by immunofluorescence staining and flow cytometry analysis in CT- 1 group. Results Transmission electron microscopic analysis revealed that cells treated with CT- 1 showed better organized sacromeric structure and more mitochondria, which are morphological characteristic of matured cardiomyocytes. Western blot demonstrated that CT-1 promotes cardiomyocyte differentiation from miPSCs partly via JAK2/STAT3/Pim-1 pathway as compared with control group. Conclusions These findings suggested that CT-1 could enhance the cardiomyocyte differentiation as well as the maturation of mouse induced pluripotent stem cell derived cardiomyocytes by regulating JAK2/STAT3/Pim-1 signaling pathway.

Heat shock protein 20 promotes sirtuin 1-dependent cell proliferation in induced pluripotent stem cells

BACKGROUND Heat shock proteins(HSPs)are molecular chaperones that protect cells against cellular stresses or injury.However,it has been increasingly recognized that they also play crucial roles in regulating fundamental cellular processes.HSP20 has been implicated in cell proliferation,but conflicting studies have shown that it can either promote or suppress proliferation.The underlying mechanisms by which HSP20 regulates cell proliferation and pluripotency remain unexplored.While the effect of HSP20 on cell proliferation has been recognized,its role in inducing pluripotency in human-induced pluripotent stem cells(iPSCs)has not been addressed.AIM To evaluate the efficacy of HSP20 overexpression in human iPSCs and evaluate the ability to promote cell proliferation.The purpose of this study was to investigate whether overexpression of HSP20 in iPSCs can increase pluripotency and regeneration.METHODS We used iPSCs,which retain their potential for cell proliferation.HSP20 overexpression effectively enhanced cell proliferation and pluripotency.Overexpression of HSP20 in iPSCs was characterized by immunocytochemistry staining and realtime polymerase chain reaction.We also used cell culture,cell counting,western blotting,and flow cytometry analyses to validate HSP20 overexpression and its mechanism.RESULTS This study demonstrated that overexpression of HSP20 can increase the pluripotency in iPSCs.Furthermore,by overexpressing HSP20 in iPSCs,we showed that HSP20 upregulated proliferation markers,induced pluripotent genes,and drove cell proliferation in a sirtuin 1(SIRT1)-dependent manner.These data have practical applications in the field of stem cell-based therapies where the mass expansion of cells is needed to generate large quantities of stem cell-derived cells for transplantation purposes.CONCLUSION We found that the overexpression of HSP20 enhanced the proliferation of iPSCs in a SIRT1-dependent manner.Herein,we established the distinct crosstalk between HSP20 and SIRT1 in regulating cell proliferation and pluripotency.Our study provides novel insights into the mechanisms controlling cell proliferation that can potentially be exploited to improve the expansion and pluripotency of human iPSCs for cell transplantation therapies.These results suggest that iPSCs overexpressing HSP20 exert regenerative and proliferative effects and may have the potential to improve clinical outcomes.