Directed Differentiation of Notochord-like and Nucleus Pulposus-like Cells Using Human Pluripotent Stem Cells

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人多能干细胞来源的肾定向分化平台的构建

肾是一种重要的人体器官,具有多种生理功能。然而,全球范围内约有10%的人口患有肾疾病。因此,建立一种接近人体肾的结构与功能的模型进行肾疾病的研究是十分必要的。多能干细胞体外定向诱导分化技术的兴起,为再生医学和精准医学领域注入了新的动力。本研究通过在体外条件下模拟体内肾发育的过程,将人多能干细胞包括胚胎干细胞和诱导多能干细胞,通过体外定向诱导分化形成肾的祖细胞,进而建立肾的结构与功能单位：肾元。该研究通过激活WNT信号通路,同时抑制TGF-β信号通路,将人多能干细胞从多能态定向诱导至原条阶段。之后通过细胞自分化的能力使其发育至中间中胚层,再通过激活FGF信号通路,将其分化至肾祖细胞阶段。流式细胞检测结果显示,肾祖细胞占总细胞数的51.5%～61.9%。通过免疫荧光检测发现：分化得到的结构中包含肾小球足细胞、近端小管、远端小管等肾组织结构。该研究建立的肾体外分化方法,具有稳定性好、分化效率高、重复性好的特点。为研究人类肾的早期发育机制,肾疾病模型构建,以及药物筛选提供了一种新的方法。     

Derivation of Airway Basal Stem Cells from Human Pluripotent Stem Cells

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A Roadmap for Human Liver Differentiation from Pluripotent Stem Cells

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Feeder-free Derivation of Neural Crest Progenitor Cells from Human Pluripotent Stem Cells

Human pluripotent stem cells (hPSCs) have great potential for studying human embryonic development, for modeling human diseases in the dish and as a source of transplantable cells for regenerative applications after disease or accidents. Neural crest (NC) cells are the precursors for a large variety of adult somatic cells, such as cells from the peripheral nervous system and glia, melanocytes and mesenchymal cells. They are a valuable source of cells to study aspects of human embryonic development, including cell fate specification and migration. Further differentiation of NC progenitor cells into terminally differentiated cell types offers the possibility to model human diseases in vitro, investigate disease mechanisms and generate cells for regenerative medicine. This article presents the adaptation of a currently available in vitro differentiation protocol for the derivation of NC cells from hPSCs. This new protocol requires 18 days of differentiation, is feeder-free, easily scalable and highly reproducible among human embryonic stem cell (hESC) lines as well as human induced pluripotent stem cell (hiPSC) lines. Both old and new protocols yield NC cells of equal identity.     

Efficient Generation Human Induced Pluripotent Stem Cells from Human Somatic Cells with Sendai-virus

A few years ago, the establishment of human induced pluripotent stem cells (iPSCs) ushered in a new era in biomedicine. Potential uses of human iPSCs include modeling pathogenesis of human genetic diseases, autologous cell therapy after gene correction, and personalized drug screening by providing a source of patient-specific and symptom relevant cells. However, there are several hurdles to overcome, such as eliminating the remaining reprogramming factor transgene expression after human iPSCs production. More importantly, residual transgene expression in undifferentiated human iPSCs could hamper proper differentiations and misguide the interpretation of disease-relevant in vitro phenotypes. With this reason, integration-free and/or transgene-free human iPSCs have been developed using several methods, such as adenovirus, the piggyBac system, minicircle vector, episomal vectors, direct protein delivery and synthesized mRNA. However, efficiency of reprogramming using integration-free methods is quite low in most cases.Here, we present a method to isolate human iPSCs by using Sendai-virus (RNA virus) based reprogramming system. This reprogramming method shows consistent results and high efficiency in cost-effective manner.     

High Efficiency Differentiation of Human Pluripotent Stem Cells to Cardiomyocytes and Characterization by Flow Cytometry

There is an urgent need to develop approaches for repairing the damaged heart, discovering new therapeutic drugs that do not have toxic effects on the heart, and improving strategies to accurately model heart disease. The potential of exploiting human induced pluripotent stem cell (hiPSC) technology to generate cardiac muscle “in a dish” for these applications continues to generate high enthusiasm. In recent years, the ability to efficiently generate cardiomyogenic cells from human pluripotent stem cells (hPSCs) has greatly improved, offering us new opportunities to model very early stages of human cardiac development not otherwise accessible. In contrast to many previous methods, the cardiomyocyte differentiation protocol described here does not require cell aggregation or the addition of Activin A or BMP4 and robustly generates cultures of cells that are highly positive for cardiac troponin I and T (TNNI3, TNNT2), iroquois-class homeodomain protein IRX-4 (IRX4), myosin regulatory light chain 2, ventricular/cardiac muscle isoform (MLC2v) and myosin regulatory light chain 2, atrial isoform (MLC2a) by day 10 across all human embryonic stem cell (hESC) and hiPSC lines tested to date. Cells can be passaged and maintained for more than 90 days in culture. The strategy is technically simple to implement and cost-effective. Characterization of cardiomyocytes derived from pluripotent cells often includes the analysis of reference markers, both at the mRNA and protein level. For protein analysis, flow cytometry is a powerful analytical tool for assessing quality of cells in culture and determining subpopulation homogeneity. However, technical variation in sample preparation can significantly affect quality of flow cytometry data. Thus, standardization of staining protocols should facilitate comparisons among various differentiation strategies. Accordingly, optimized staining protocols for the analysis of IRX4, MLC2v, MLC2a, TNNI3, and TNNT2 by flow cytometry are described.     

Organoid-Induced Differentiation of Conventional T Cells from Human Pluripotent Stem Cells

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Aggregate Size Optimization in Microwells for Suspension-based Cardiac Differentiation of Human Pluripotent Stem Cells

Cardiac differentiation of human pluripotent stems cells (hPSCs) is typically carried out in suspension cell aggregates. Conventional aggregate formation of hPSCs involves dissociating cell colonies into smaller clumps, with size control of the clumps crudely controlled by pipetting the cell suspension until the desired clump size is achieved. One of the main challenges of conventional aggregate-based cardiac differentiation of hPSCs is that culture heterogeneity and spatial disorganization lead to variable and inefficient cardiomyocyte yield. We and others have previously reported that human embryonic stem cell (hESC) aggregate size can be modulated to optimize cardiac induction efficiency. We have addressed this challenge by employing a scalable, microwell-based approach to control physical parameters of aggregate formation, specifically aggregate size and shape. The method we describe here consists of forced aggregation of defined hPSC numbers in microwells, and the subsequent culture of these aggregates in conditions that direct cardiac induction. This protocol can be readily scaled depending on the size and number of wells used. Using this method, we can consistently achieve culture outputs with cardiomyocyte frequencies greater than 70%.     

Transcriptional Programming of Human Mechanosensory Neuron Subtypes from Pluripotent Stem Cells

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Feeder-free Derivation of Melanocytes from Human Pluripotent Stem Cells

Human pluripotent stem cells (hPSCs) represent a platform to study human development in vitro under both normal and disease conditions. Researchers can direct the differentiation of hPSCs into the cell type of interest by manipulating the culture conditions to recapitulate signals seen during development. One such cell type is the melanocyte, a pigment-producing cell of neural crest (NC) origin responsible for protecting the skin against UV irradiation. This protocol presents an extension of a currently available in vitro Neural Crest differentiation protocol from hPSCs to further differentiate NC into fully pigmented melanocytes. Melanocyte precursors can be enriched from the Neural Crest protocol via a timed exposure to activators of WNT, BMP, and EDN3 signaling under dual-SMAD-inhibition conditions. The resultant melanocyte precursors are then purified and matured into fully pigmented melanocytes by culture in a selective medium. The resultant melanocytes are fully pigmented and stain appropriately for proteins characteristic of mature melanocytes.     

Selecting and Isolating Colonies of Human Induced Pluripotent Stem Cells Reprogrammed from Adult Fibroblasts

Herein we present a protocol of reprogramming human adult fibroblasts into human induced pluripotent stem cells (hiPSC) using retroviral vectors encoding Oct3/4, Sox2, Klf4 and c-myc (OSKM) in the presence of sodium butyrate ^1-3. We used this method to reprogram late passage (>p10) human adult fibroblasts derived from Friedreich''s ataxia patient (GM03665, Coriell Repository). The reprogramming approach includes highly efficient transduction protocol using repetitive centrifugation of fibroblasts in the presence of virus-containing media. The reprogrammed hiPSC colonies were identified using live immunostaining for Tra-1-81, a surface marker of pluripotent cells, separated from non-reprogrammed fibroblasts and manually passaged ^4,5. These hiPSC were then transferred to Matrigel plates and grown in feeder-free conditions, directly from the reprogramming plate. Starting from the first passage, hiPSC colonies demonstrate characteristic hES-like morphology. Using this protocol more than 70% of selected colonies can be successfully expanded and established into cell lines. The established hiPSC lines displayed characteristic pluripotency markers including surface markers TRA-1-60 and SSEA-4, as well as nuclear markers Oct3/4, Sox2 and Nanog. The protocol presented here has been established and tested using adult fibroblasts obtained from Friedreich''s ataxia patients and control individuals ⁶, human newborn fibroblasts, as well as human keratinocytes.     

Generation of Integration-free Human Induced Pluripotent Stem Cells Using Hair-derived Keratinocytes

Recent advances in reprogramming allow us to turn somatic cells into human induced pluripotent stem cells (hiPSCs). Disease modeling using patient-specific hiPSCs allows the study of the underlying mechanism for pathogenesis, also providing a platform for the development of in vitro drug screening and gene therapy to improve treatment options. The promising potential of hiPSCs for regenerative medicine is also evident from the increasing number of publications (>7000) on iPSCs in recent years. Various cell types from distinct lineages have been successfully used for hiPSC generation, including skin fibroblasts, hematopoietic cells and epidermal keratinocytes. While skin biopsies and blood collection are routinely performed in many labs as a source of somatic cells for the generation of hiPSCs, the collection and subsequent derivation of hair keratinocytes are less commonly used. Hair-derived keratinocytes represent a non-invasive approach to obtain cell samples from patients. Here we outline a simple non-invasive method for the derivation of keratinocytes from plucked hair. We also provide instructions for maintenance of keratinocytes and subsequent reprogramming to generate integration-free hiPSC using episomal vectors.     

人椎间盘髓核来源的诱导多能干细胞重编程及功能的研究

椎间盘退变始发于髓核组织,获得足够有功能的髓核细胞是研究及治疗椎间盘退变的关键.而人诱导多能干细胞(induced pluripotent stem cell,iPSC)不仅为建立疾病模型以研究疾病发生发展机制开辟了道路,还在再生医学领域展现出了广阔的应用前景.我们首先从椎间盘退变患者微创手术获得的髓核组织内分离髓核细胞,将携带OCT3/4、SOX2、KLF4和c-MYC的仙台病毒(Sendai virus,Se V)转染髓核细胞,重编程获得iPSC.通过检测多能细胞特异性标志、体内成瘤实验、甲基化及核型分析对所获得的iPSC进行鉴定.并以皮肤成纤维细胞来源iPSC作为对照,在二维和三维水凝胶中对iPSC进行定向分化,检测髓核细胞相关蛋白和基因的表达,比较分析2种iPSC向髓核细胞的分化效率.结果显示,iPSC能表达多能细胞特异性标志,具有正常的二倍体核型,畸胎瘤实验显示三个胚层的出现.诱导分化后的iPSC表达髓核相关基因和蛋白,在水凝胶中诱导培养后,iPSC表达更多的髓核相关基因和蛋白.髓核来源的iPSC与成纤维细胞来源的iPSC相比,可表达更多的髓核相关基因和蛋白.本研究首次将患者退变髓核细胞重编程成iPSC,并在水凝胶内将其诱导分化为髓核样细胞,为椎间盘退变个体化细胞治疗奠定基础.     

Generation of Induced Pluripotent Stem Cells from Human Peripheral T Cells Using Sendai Virus in Feeder-free Conditions

Recently, iPSCs have attracted attention as a new source of cells for regenerative therapies. Although the initial method for generating iPSCs relied on dermal fibroblasts obtained by invasive biopsy and retroviral genomic insertion of transgenes, there have been many efforts to avoid these disadvantages. Human peripheral T cells are a unique cell source for generating iPSCs. iPSCs derived from T cells contain rearrangements of the T cell receptor (TCR) genes and are a source of antigen-specific T cells. Additionally, T cell receptor rearrangement in the genome has the potential to label individual cell lines and distinguish between transplanted and donor cells. For safe clinical application of iPSCs, it is important to minimize the risk of exposing newly generated iPSCs to harmful agents. Although fetal bovine serum and feeder cells have been essential for pluripotent stem cell culture, it is preferable to remove them from the culture system to reduce the risk of unpredictable pathogenicity. To address this, we have established a protocol for generating iPSCs from human peripheral T cells using Sendai virus to reduce the risk of exposing iPSCs to undefined pathogens. Although handling Sendai virus requires equipment with the appropriate biosafety level, Sendai virus infects activated T cells without genome insertion, yet with high efficiency. In this protocol, we demonstrate the generation of iPSCs from human peripheral T cells in feeder-free conditions using a combination of activated T cell culture and Sendai virus.     

Coculture of Endothelial Cells with Human Pluripotent Stem Cell‐Derived Cardiac Progenitors Reveals a Differentiation Stage‐Specific Enhancement of Cardiomyocyte Maturation

Cardiomyocytes (CMs) generated from human pluripotent stem cells (hPSCs) are immature in their structure and function, limiting their potential in disease modeling, drug screening, and cardiac cellular therapies. Prior studies have demonstrated that coculture of hPSC‐derived CMs with other cardiac cell types, including endothelial cells (ECs), can accelerate CM maturation. To address whether the CM differentiation stage at which ECs are introduced affects CM maturation, the authors coculture hPSC‐derived ECs with hPSC‐derived cardiac progenitor cells (CPCs) and CMs and analyze the molecular and functional attributes of maturation. ECs have a more significant effect on acceleration of maturation when cocultured with CPCs than with CMs. EC coculture with CPCs increases CM size, expression of sarcomere, and ion channel genes and proteins, the presence of intracellular membranous extensions, and chronotropic response compared to monoculture. Maturation is accelerated with an increasing EC:CPC ratio. This study demonstrates that EC incorporation at the CPC stage of CM differentiation expedites CM maturation, leading to cells that may be better suited for in vitro and in vivo applications of hPSC‐derived CMs.     

The Aurora Kinase Inhibitor CYC116 Promotes the Maturation of Cardiomyocytes Derived from Human Pluripotent Stem Cells

Human pluripotent stem cell-derived cardiomyocytes (hPSC-CMs) have great potential in applications such as regenerative medicine, cardiac disease modeling, and in vitro drug evaluation. However, hPSC-CMs are immature, which limits their applications. During development, the maturation of CMs is accompanied by a decline in their proliferative capacity. This phenomenon suggests that regulating the cell cycle may facilitate the maturation of hPSC-CMs. Aurora kinases are essential kinases that regulate the cell cycle, the role of which is not well studied in hPSC-CM maturation. Here, we demonstrate that CYC116, an inhibitor of Aurora kinases, significantly promotes the maturation of CMs derived from both human embryonic stem cells (H1 and H9) and iPSCs (induced PSCs) (UC013), resulting in increased expression of genes related to cardiomyocyte function, better organization of the sarcomere, increased sarcomere length, increased number of mitochondria, and enhanced physiological function of the cells. In addition, a number of other Aurora kinase inhibitors have also been found to promote the maturation of hPSC-CMs. Our data suggest that blocking aurora kinase activity and regulating cell cycle progression may promote the maturation of hPSC-CMs.