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.

Human pluripotent stem cell-derived kidney organoids:Current progress and challenges

Human pluripotent stem cell(hPSC)-derived kidney organoids share similarities with the fetal kidney.However,the current hPSC-derived kidney organoids have some limitations,including the inability to perform nephrogenesis and lack of a corticomedullary definition,uniform vascular system,and coordinated exit path-way for urinary filtrate.Therefore,further studies are required to produce hPSC-derived kidney organoids that accurately mimic human kidneys to facilitate research on kidney development,regeneration,disease modeling,and drug screening.In this review,we discussed recent advances in the generation of hPSC-derived kidney organoids,how these organoids contribute to the understanding of human kidney development and research in disease modeling.Additionally,the limitations,future research focus,and applications of hPSC-derived kidney organoids were highlighted.

Human pluripotent stem cell-derivedβcells:Truly immature isletβcells for type 1 diabetes therapy?

A century has passed since the Nobel Prize winning discovery of insulin,which still remains the mainstay treatment for type 1 diabetes mellitus(T1DM)to this day.True to the words of its discoverer Sir Frederick Banting,“insulin is not a cure for diabetes,it is a treatment”,millions of people with T1DM are dependent on daily insulin medications for life.Clinical donor islet transplantation has proven that T1DM is curable,however due to profound shortages of donor islets,it is not a mainstream treatment option for T1DM.Human pluripotent stem cell derived insulin-secreting cells,pervasively known as stem cell-derivedβcells(SC-βcells),are a promising alternative source and have the potential to become a T1DM treatment through cell replacement therapy.Here we briefly review how isletβcells develop and mature in vivo and several types of reported SC-βcells produced using different ex vivo protocols in the last decade.Although some markers of maturation were expressed and glucose stimulated insulin secretion was shown,the SC-βcells have not been directly compared to their in vivo counterparts,generally have limited glucose response,and are not yet fully matured.Due to the presence of extra-pancreatic insulin-expressing cells,and ethical and technological issues,further clarification of the true nature of these SC-βcells is required.

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

遗传上在人的导致的 pluripotent 干细胞(iPSCs ) 改正一个引起疾病的点变化的目的首先源于出血不止 B patient.Methods，引起疾病的变化被定序人的凝结因素 IX (F IX ) 的编码区域检测基因。Genomic DNA 从 iPSCs 被提取，并且教材被设计放大 F IX 的八 exons。下次，在那些 iPSCs 的点变化遗传上面对 129 核苷酸用 CRISPR/Cas9 技术被改正包含了二个同义的变化的相应修理模板。然后，顶 8 潜在的离开目标地点随后用定序的 Sanger 被分析。最后，改正的克隆被区分进象 hepatocyte 一样房间，并且 F IX 的分泌物被房间行厌烦的 immunocytochemistry 和 ELISA assay.Results 验证在 6 th 编码 exon (c.676 C > T ) F IX 基因。点变化的修正与在大约 22% 点的功效(10/45 ) 和没有离开目标效果在改正的 iPSC 克隆检测了的高度在 situ 经由 CRISPR/Cas9 技术被完成。F IX 分泌物，被 immunocytochemistry 进一步设想并且在 vitro 由 ELISA 确定了，在人的疾病特定的 iPSCs 在白天 21 区别 procedure.Conclusions 变化上到达了大约 6 ng/ml 能被 CRISPR/Cas9 技术精确改正，并且改正了仍然维持的房间肝的区别能力。我们的调查结果可能在临床的应用程序在基于 iPSC 的个性化的治疗上扔一盏灯，特别为出血不止 B。

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

人的导致的 pluripotent 茎(iPS ) 房间类似于胚胎的茎(ES ) 房间，和罐头强烈地增殖并且区分进许多房间类型。然而，人的 iPS 房间的肝的区别还没被报导了。在这份报告，人的 iPS 房间被导致由一个逐步的协议区分进肝的房间。肝房间标记的表达式和人的 iPS 的肝相关的函数导出房间的房间被监视并且与区分的人的 ES 房间和主要人的 hepatocytes 的相比。在白天 7 点的约 60% 区分的人的 iPS 房间表示了肝的标记 alpha fetoprotein 和白长袍的。在白天 21 点的区分的房间包括白朊 Asecretion，肝糖合成，脲生产和可诱导的细胞色素 P450 活动展出了肝房间功能。肝的标记的表示和 iPS 的肝相关的功能导出房间的肝的房间比得上人的 ES 导出房间的肝的房间的。这些结果证明人的 iPS 房间，类似于人的 ES 房间，能高效地被导致区分房间进象 hepatocyte 一样。

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.

Human induced pluripotent stem cells for monogenic disease modelling and therapy

Recent and advanced protocols are now available toderive human induced pluripotent stem cells(hi PSCs)from patients affected by genetic diseases.No curative treatments are available for many of these diseases;thus,hiP SCs represent a major impact on patient’health.hiP SCs represent a valid model for the in vitro study of monogenic diseases,together with a better comprehension of the pathogenic mechanisms of the pathology,for both cell and gene therapy protocol applications.Moreover,these pluripotent cells represent a good opportunity to test innovative pharmacological treatments focused on evaluating the efficacy and toxicity of novel drugs.Today,innovative gene therapy protocols,especially gene editingbased,are being developed,allowing the use of these cells not only as in vitro disease models but also as an unlimited source of cells useful for tissue regeneration and regenerative medicine,eluding ethical and immune rejection problems.In this review,we will provide an upto-date of modelling monogenic disease by using hiP SCs and the ultimate applications of these in vitro models for cell therapy.We consider and summarize some peculiar aspects such as the type of parental cells used for reprogramming,the methods currently used to induce the transcription of the reprogramming factors,and the type of iP SC-derived differentiated cells,relating them to the genetic basis of diseases and to their inheritance model.

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.

Human induced pluripotent stem cells: A new source for brown and white adipocytes

Mesenchymal stem cells(MSCs) derived from human induced pluripotent stem cells(hiPSCs) provide a novel source for generating adipocytes, thus opening new avenues for fundamental research and clinical medicine. We present the adipogenic potential of hiPSCs and the various methods to derive hiPSC-MSCs. We discuss the main characteristic of hiPSC-MSCs, which is their low adipogenic capacity as compared to adult-MSCs. Finally, we propose several hypotheses to explanation this feature, underlying a potential critical role of the micro-environment. We favour the hypothesis that the range of factors or culture conditions required to induce adipocyte differentiation of MSCs derived from adult tissues and from embryonic-like cells could differ.

Human induced pluripotent stem cells labeled with fluorescent magnetic nanoparticles for targeted imaging and hyperthermia therapy for gastric cancer

Objective: Human induced pluripotent stem(i PS) cells exhibit great potential for generating functional human cells for medical therapies. In this paper, we report for use of human i PS cells labeled with fluorescent magnetic nanoparticles(FMNPs) for targeted imaging and synergistic therapy of gastric cancer cells in vivo. Methods: Human i PS cells were prepared and cultured for 72 h. The culture medium was collected, and then was coincubated with MGC803 cells. Cell viability was analyzed by the MTT method. FMNP-labeled human i PS cells were prepared and injected into gastric cancer-bearing nude mice. The mouse model was observed using a small-animal imaging system. The nude mice were irradiated under an external alternating magnetic field and evaluated using an infrared thermal mapping instrument. Tumor sizes were measured weekly. Results: iP S cells and the collected culture medium inhibited the growth of MGC803 cells. FMNP-labeled human iP S cells targeted and imaged gastric cancer cells in vivo, as well as inhibited cancer growth in vivo through the external magnetic field. Conclusion: FMNP-labeled human i PS cells exhibit considerable potential in applications such as targeted dual-mode imaging and synergistic therapy for early gastric cancer.

Cardiac disease modeling using induced pluripotent stem cell-derived human cardiomyocytes

Causative mutations and variants associated with cardiac diseases have been found in genes encoding cardiac ion channels, accessory proteins, cytoskeletal components, junctional proteins, and signaling molecules. In most cases the functional evaluation of the genetic alterationhas been carried out by expressing the mutated proteins in in-vitro heterologous systems. While these studies have provided a wealth of functional details that have greatly enhanced the understanding of the pathological mechanisms, it has always been clear that heterologous expression of the mutant protein bears the intrinsic limitation of the lack of a proper intracellular environment and the lack of pathological remodeling. The results obtained from the application of the next generation sequencing technique to patients suffering from cardiac diseases have identified several loci, mostly in non-coding DNA regions, which still await functional analysis. The isolation and culture of human embryonic stem cells has initially provided a constant source of cells from which cardiomyocytes(CMs) can be obtained by differentiation. Furthermore, the possibility to reprogram cellular fate to a pluripotent state, has opened this process to the study of genetic diseases. Thus induced pluripotent stem cells(i PSCs) represent a completely new cellular model that overcomes the limitations of heterologous studies. Importantly, due to the possibility to keep spontaneously beating CMs in culture for several months, during which they show a certain degree of maturation/aging, this approach will also provide a system in which to address the effect of long-term expression of the mutated proteins or any other DNA mutation, in terms of electrophysiological remodeling. Moreover, since i PSC preserve the entire patients' genetic context, the system will help the physicians in identifying the most appropriate pharmacological intervention to correct the functional alteration. This article summarizes the current knowledge of cardiac genetic diseases modelled with i PSC.

Pro-vs anti-stenotic capacities of type-Ⅰ vs type-Ⅱ human induced pluripotent-derived endothelial cells

AIM:To verify in vivo relevance of the categorization of human vascular endothelial cells(VECs)into type-I(proproliferative)and type-II(anti-proliferative).METHODS:Endothelial layers of murine femoral arteries were removed by wire injury(WI)operation,a common technique to induce arteriostenosis.Type-I and type-II VECs produced from human induced pluripotent stem cells(iPSCs),whose characters were previously determined by their effects on the proliferation of vascular smooth muscle cells in in vitro co-culture experiments,were mixed with Matrigel?Matrix.The mixtures were injected into subcutaneous spaces around WI-operated femoral arteries for the transplanted human iPSC-derived VECs(iPSdECs)to take a route to the luminal surface via vasa vasorum,a nutrient microvessel for larger arteries.Histologies of the femoral arteries were examined over time.The presence of human iPSdECs was checked by immunostaining studies using an antibody that specifically recognizes human VECs.Degrees of stenosis of the femoral arteries were calculated after three weeks.To determine the optimal experimental condition,xenotransplantation experiments were performed under various conditions using immunocompromised mice as well as immunocompetent mice with or without administration of immunosuppressants.RESULTS:Because immunocompromised mice showed unexpected resistance to WI-induced arteriostenosis,we performed xenotransplantation experiments using immunocompetent mice along with immunosuppressant administrations.After one week,luminal surfaces of the WI-operated arteries were completely covered by human iPSdECs,showing the efficacy of our novel transplantation technique.After three weeks,type-IiPSdECs-transplanted arteries underwent total stenosis,while type-II-iPSdECs-transplanted arteries remained intact.However,untransplanted arteries of immunosuppressant-treated mice also remained intact by unknown reasons.We found that transplanted human VECs had already been replaced by murine endothelial cells by this time,indicating that a transient existence of human type-II-iPSdECs on arterial luminal surfaces can sufficiently prevent the development of stenosis.Thus,we re-performed xenotransplantation experiments using immunocompetent mice without administrating immunosuppressants and found that arteriostenosis was accelerated or prevented by transplantation of type-I or type-II iPSdECs,respectively.Similar results were obtained from the experiments using human embryonic stem cell-derived VECs at early passages(i.e.,type-II)and late passages(i.e.,type-I).CONCLUSION:Pro-and anti-stenosis capacities of type-I and type-II human iPSdECs were verified,respectively,promising a therapeutic application of allogenic iPSdECs.

Exploring pre-degenerative alterations in humans using induced pluripotent stem cell-derived dopaminergic neurons

Understanding the cellular and molecular mechanisms underlying human neurological disorders is hindered by both the complexity of the disorders and the lack of suitable experimental models recapitulating key pathological features of the disease.This is a crucial issue since a limited understanding of pathogenic mechanisms precludes the development of drugs counteracting the progression of the disease.Among neurological disorders,

Functional and molecular mechanism of intracellular pH regulation in human inducible pluripotent stem cells

AIM To establish a functional and molecular model of the intracellular pH(pH_i) regulatory mechanism in human induced pluripotent stem cells(hiPSCs).METHODS hiP SCs(HPS0077) were kindly provided by Dr. Dai from the Tri-Service General Hospital(IRB No. B-106-09). Changes in the pH_i were detected either by microspectrofluorimetry or by a multimode reader with a pH-sensitive fluorescent probe, BCECF, and the fluorescent ratio was calibrated by the high K^+/nigericin method. NH_4Cl and Na-acetate prepulse techniques were used to induce rapid intracellular acidosis and alkalization, respectively. The buffering power(β) was calculated from the ΔpH_i induced by perfusing different concentrations of(NH_4)_2SO_4. Western blot techniques and immunocytochemistry staining were used to detect the protein expression of pH_i regulators and pluripotency markers.RESULTS In this study, our results indicated that(1) the steadystate pH_i value was found to be 7.5 ± 0.01(n = 20) and 7.68 ± 0.01(n =20) in HEPES and 5% CO_2/HCO_3^- buffered systems, respectively, which were much greater than that in normal adult cells(7.2);(2) in a CO_2/HCO_3^--buffered system, the values of total intracellular buffering power(β) can be described by the following equation: β_(tot) = 107.79(pH_i)~2-1522.2(pH_i) + 5396.9(correlation coefficient R^2 = 0.85), in the estimated pH_i range of 7.1- 8.0;(3) the Na^+/H^+ exchanger(NHE) and the Na^+/HCO_3^- cotransporter(NBC) were found to be functionally activated for acid extrusion for pHi values less than 7.5 and 7.68, respectively;(4) V-ATPase and some other unknown Na^+-independent acid extruder(s) could only be functionally detected for pHi values less than 7.1;(5) the Cl^-/OH^- exchanger(CHE) and the Cl^- /HCO_3 anion exchanger(AE) were found to be responsible for the weakening of intracellular proton loading;(6) besides the CHE and the AE, a Cl^--independent acid loading mechanism was functionally identified; and(7) in hiPSCs, a strong positive correlation was observed between the loss of pluripotency and the weakening of the intracellular acid extrusion mechanism, which included a decrease in the steady-state pH i value and diminished the functional activity and protein expression of the NHE and the NBC.CONCLUSION For the first time, we established a functional and molecular model of a pHi regulatory mechanism and demonstrated its strong positive correlation with hiPSC pluripotency.

Human induced pluripotent stem cell based in vitro models of the blood-brain barrier： the future standard？

There is an urgent and tremendous need for human dis- ease models in drug development in order to improve pre- clinical predictability. In the case of brain disorders drugs have to cross the blood-brain barrier （BBB） to enter the central nervous system （CNS）. It was estimated that more than 95% of the drugs cannot cross the BBB.

One-step cell biomanufacturing platform:porous gelatin microcarrier beads promote human embryonic stem cell-derived midbrain dopaminergic progenitor cell differentiation in vitro and survival after transplantation in vivo

Numerous studies have shown that cell replacement therapy can replenish lost cells and rebuild neural circuitry in animal models of Parkinson’s disease.Transplantation of midbrain dopaminergic progenitor cells is a promising treatment for Parkinson’s disease.However,transplanted cells can be injured by mechanical damage during handling and by changes in the transplantation niche.Here,we developed a one-step biomanufacturing platform that uses small-aperture gelatin microcarriers to produce beads carrying midbrain dopaminergic progenitor cells.These beads allow midbrain dopaminergic progenitor cell differentiation and cryopreservation without digestion,effectively maintaining axonal integrity in vitro.Importantly,midbrain dopaminergic progenitor cell bead grafts showed increased survival and only mild immunoreactivity in vivo compared with suspended midbrain dopaminergic progenitor cell grafts.Overall,our findings show that these midbrain dopaminergic progenitor cell beads enhance the effectiveness of neuronal cell transplantation.

Nutrient supplemented serum-free medium increases cardiomyogenesis efficiency of human pluripotent stem cells

AIM: To development of an improved p38 MAPK inhibitor-based serum-free medium for embryoid body cardiomyocyte differentiation of human pluripotent stem cells. METHODS: Human embryonic stem cells (hESC) differentiated to cardiomyocytes (CM) using a p38 MAPK inhibitor (SB203580) based serum-free medium (SB media). Nutrient supplements known to increase cell viability were added to SB medium. The ability of these supplements to improve cardiomyogenesis was evaluated by measurements of cell viability, total cell count, and the expression of cardiac markers via flow cytometry. An improved medium containing Soy hydrolysate (HySoy) and bovine serum albumin (BSA) (SupSB media) was developed and tested on 2 additional cell lines (H1 and Siu-hiPSC). Characterization of the cardiomyocytes was done by immunohistochemistry, electrophysiology and quantitative real-time reverse transcriptionpolymerase chain reaction. RESULTS: hESC cell line, HES-3, differentiating in SB medium for 16 d resulted in a cardiomyocyte yield of 0.07 ± 0.03 CM/hESC. A new medium (SupSB media) was developed with the addition of HySoy and BSA to SB medium. This medium resulted in 2.6 fold increase in cardiomyocyte yield (0.21 ± 0.08 CM/hESC). The robustness of SupSB medium was further demonstrated using two additional pluripotent cell lines (H1, hESC and Siu1, hiPSC), showing a 15 and 9 fold increase in cardiomyocyte yield respectively. The age (passage number) of the pluripotent cells did not affect the cardiomyocyte yields. Embryoid body (EB) cardiomyocytes formed in SupSB medium expressed canonical cardiac markers (sarcomeric α-actinin, myosin heavy chain and troponin-T) and demonstrated all three major phenotypes: nodal-, atrial- and ventricular-like. Electrophysiological characteristics (maximum diastolic potentials and action potential durations) of cardiomyocytes derived from SB and SupSB media were similar. CONCLUSION: The nutrient supplementation (HySoy and BSA) leads to increase in cell viability, cell yield and cardiac marker expression during cardiomyocyte differentiation, translating to an overall increase in cardiomyocyte yield.

Human pluripotent stem cells:Towards therapeutic development for the treatment of lifestyle diseases

There are two types of human pluripotent stem cells: Embryonic stem cells(ESCs) and induced pluripotent stem cells(iPSCs),both of which launched themselves on clinical trials after having taken measures to overcome problems: Blocking rejections by immunosuppressants regarding ESCs and minimizing the risk of tumorigenicity by depleting exogenous gene components regarding iP SCs.It is generally assumed that clinical applications of human pluripotent stem cells should be limited to those cases where there are no alternative measures for treatments because of the risk in transplanting those cells to living bodies.Regarding lifestyle diseases,we have already several therapeutic options,and thus,development of human pluripotent stem cell-based therapeutics tends to be avoided.Nevertheless,human pluripotent stem cells can contribute to the development of new therapeutics in this field.As we will show,there is a case where only a short-term presence of human pluripotent stem-derived cells can exert long-term therapeutic effects even after they are rejected.In those cases,immunologically rejections of ESC-or allogenic iP SC-derived cells may produce beneficial outcomes by nullifying the risk of tumorigenesis without deterioration of therapeutic effects.Another utility of human pluripotent stem cells is the provision of an innovative tool for drug discovery that are otherwise unavailable.For example,clinical specimens of human classical brown adipocytes(BAs),which has been attracting a great deal of attention as a new target of drug discovery for the treatment of metabolic disorders,are unobtainable from living individuals due to scarcity,fragility and ethical problems.However,BA can easily be produced from human pluripotent stem cells.In this review,we will contemplate potential contribution of human pluripotent stem cells to therapeutic development for lifestyle diseases.

Predicting differentiation potential of human pluripotent stem cells:Possibilities and challenges

The capability of human pluripotent stem cell(hPSC)lines to propagate indefinitely and differentiate into derivatives of three embryonic germ layers makes these cells be powerful tools for basic scientific research and promising agents for translational medicine.However,variations in differentiation tendency and efficiency as well as pluripotency maintenance necessitate the selection of hPSC lines for the intended applications to save time and cost.To screen the qualified cell lines and exclude problematic cell lines,their pluripotency must be confirmed initially by traditional methods such as teratoma formation or by highthroughput gene expression profiling assay.Additionally,their differentiation potential,particularly the lineage-specific differentiation propensities of hPSC lines,should be predicted in an early stage.As a complement to the teratoma assay,RNA sequencing data provide a quantitative estimate of the differentiation ability of hPSCs in vivo.Moreover,multiple scorecards have been developed based on selected gene sets for predicting the differentiation potential into three germ layers or the desired cell type many days before terminal differentiation.For clinical application of hPSCs,the malignant potential of the cells must also be evaluated.A combination of histologic examination of teratoma with quantitation of gene expression data derived from teratoma tissue provides safety-related predictive information by detecting immature teratomas,malignancy marker expression,and other parameters.Although various prediction methods are available,distinct limitations remain such as the discordance of results between different assays and requirement of a long time and high labor and cost,restricting their wide applications in routine studies.Therefore,simpler and more rapid detection assays with high specificity and sensitivity that can be used to monitor the status of hPSCs at any time and fewer targeted markers that are more specific for a given desired cell type are urgently needed.

Deriving striatal projection neurons from human pluripotent stem cells with Activin A

The striatum is the main input structure of the basal ganglia and is involved in voluntary motor control,habit learning and reward processing.Medium spiny neurons（MSNs）comprise80%and 95%of striatal neurons in primates and rodents,respectively.