Sendai Virus Vector Research Articles

A Sendai virus-based expression system directs efficient induction of chondrocytes by transcription factor-mediated reprogramming.

Cartilage rarely heals spontaneously once damaged. Osteoarthritis (OA) is the most common degenerative joint disease among the elderly; however, effective treatment for OA is currently lacking. Autologous chondrocyte implantation (ACI), an innovative regenerative technology involving the implantation of healthy chondrocytes, may restore damaged lesions. Chondrocytes for ACI may potentially be induced from differentiated somatic cells using retrovirus (RV)-mediated transduction of three reprogramming factors (SOX9, KLF4, and c-MYC). However, the efficiency of the current induction system needs to be improved and the safety issues arising from the genomic integration of the vector DNA have to be addressed. To solve these problems, we used an RNA vector, termed the replication-defective and persistent Sendai virus vector (SeVdp), to express reprogramming factors for chondrocyte induction. Our results showed that the SeVdp-based vector induced chondrocytes more efficiently than the RV vector, probably because of robust and rapid expression of the transgenes, without any apparent integration of the SeVdp vector. The induced chondrocytes formed cartilage-like tissues when injected subcutaneously into mice. Thus, the SeVdp-based system for inducing chondrocytes may act as a foundation for developing safer and more effective treatments for damaged cartilage.

Mitochondrial morphology and energy metabolism in reprogrammed porcine expanded potential stem cells.

Expanded potential stem cells (EPSCs) are stem cells that can differentiate into embryonic and extraembryonic lineages, including extraembryonic endoderm and trophoblast lineages. Therefore, EPSCs have great potential in advancing regenerative medicine, elucidating disease mechanisms, and exploring early embryonic development. However, the generation and characterization of EPSCs in pigs have not been thoroughly explored. In this study, we successfully generated porcine EPSCs (pEPSCs). We reprogrammed porcine fetal fibroblasts (PFFs) using an integration-free method with Sendai virus vectors. The resulting pEPSCs expressed key pluripotency markers and demonstrated the ability to differentiate between embryonic and extraembryonic lineages. Notably, reprogramming into pEPSCs was associated with a transformation of mitochondrial morphology from the elongated form observed in PFFs to a globular shape, reflecting potential alterations in energy metabolism. We observed significant remodeling of mitochondrial morphology and a subsequent shift towards glycolytic energy dependence during the reprogramming of PFFs into pEPSCs. Our findings provide valuable insights into the characteristics of EPSCs in pigs and highlight their potential applications in regenerative medicine, disease modeling, and emerging fields such as cell-based meat production.

Rejuvenation of human mesenchymal stem cells using a nonintegrative and conditionally removable Sendai virus vector

Human mesenchymal stem cells (hMSCs) with extended lifespan and differentiation potential that can recapitulate in vivo characteristics could significantly contribute to basic research, drug development, and cell therapy. Specifically, they could ensure a stable supply of specific cellular resources, and possibly extracellular vesicles. Here, we established a technology for extending the lifespan while maintaining differentiation potential, termed “rejuvenation,” of hMSCs (rej-hMSCs) using nonintegrative and conditionally removable temperature-sensitive Sendai virus (SeV) vectors. Various immortalizing factors (i.e., Bmi-1, hTERT, SV40T, and/or HPV E6/E7) were first introduced by the SeV vector into the cells. A combination of three SeVs with Bmi-1, hTERT, or SV40T conferred markedly improved cell proliferation and cloning ability while maintaining differentiation potential and a normal karyotype. An extended lifespan was also demonstrated in other cell types. The rejuvenation of long-passaged or aged hMSCs was also confirmed. SeV vectors were rapidly removed as a function of cell doubling by increasing the temperature from 35 °C to 37 °C or higher, while proliferative ability was maintained. Following FACS sorting, the complete removal of SeV vectors was confirmed by qPCR analyses. Therefore, our cell rejuvenation technology could contribute to research and clinical applications by enabling the supply of modified cells without damaging host chromosomes.

Generation of human induced pluripotent stem cell lines derived from four Rett syndrome patients with MECP2 mutations

Rett syndrome is characterized by severe global developmental impairments with autistic features and loss of purposeful hand skills. Here we show that human induced pluripotent stem cell (hiPSC) lines derived from four Japanese female patients with Rett syndrome are generated from peripheral blood mononuclear cells using Sendai virus vectors. The generated hiPSC lines showed self-renewal and pluripotency and carried heterozygous frameshift, missense, or nonsense mutations in the MECP2 gene. Since the molecular pathogenesis caused by MECP2 dysfunction remains unclear, these cell resources are useful tools to establish disease models and develop new therapies for Rett syndrome.

Characterization of immortalized ovarian epithelial cells with BRCA1/2 mutation.

We aimed to elucidate the mechanism underlying carcinogenesis by comparing normal and BRCA1/2-mutated ovarian epithelial cells established via Sendai virus-based immortalization. Ovarian epithelial cells (normal epithelium: Ovn; with germline BRCA1 mutation: OvBRCA1; with germline BRCA2 mutation: OvBRCA2) were infected with Sendai virus vectors carrying three immortalization genes (Bmi-1, hTERT, and SV40T). The immunoreactivity to anti-epithelial cellular adhesion molecule (EpCAM) antibodies in each cell line and cells after 25 passages was confirmed using flow cytometry. Chromosomes were identified and karyotyped to detect numerical and structural abnormalities. Total RNA extracted from the cells was subjected to human transcriptome sequencing. Highly expressed genes in each cell line were confirmed using real-time polymerase chain reaction. Immortalization techniques allowed 25 or more passages of Ovn, OvBRCA1, and OvBRCA2 cells. No anti-EpCAM antibody reactions were observed in primary cultures or after long-term passages of each cell line. Structural abnormalities in the chromosomes were observed in each cell line; however, the abnormal chromosomes were successfully separated from the normal structures via cloning. Only normal cells from each cell line were cloned. MMP1, CCL2, and PAPPA were more predominantly expressed in OvBRCA1 and OvBRCA2 cells than in Ovn cells. Immortalized ovarian cells derived from patients with germline BRCA1 or BRCA2 mutations showed substantially higher MMP1 expression than normal ovarian cells. However, the findings need to be validated in the future.

Generation of human induced pluripotent stem cell line (XWHNi004-A) from a male with APOE gene mutation

Genetic polymorphism of apolipoprotein E (APOE) confers differential susceptibility to Alzheimer's disease (AD), and APOE ɛ4 variants is the most powerful risk factor for this disease. Here, we report the generation of a human induced pluripotent stem cell (iPSC) line carrying the APOE ɛ4/ɛ4 genotype from peripheral blood mononuclear cells (PBMCs) isolated from a male with a family history of AD utilizing non-integrative Sendai virus vector. The iPSC maintains their original genotype, highly express endogenous pluripotency markers, displays a normal karyotype, and retains the ability to differentiate into cells representative of the three germ layers.

Generation of human-induced pluripotent stem cell line from PBMC of healthy donor using integration-free Sendai virus technology

We developed a well-characterized human induced pluripotent stem cell (iPSC) line obtained from healthy individuals' peripheral blood mononuclear cells (PBMC). The PBMCs were primed and reprogrammed using a non-integrating sendai viral vector, and the iPSC lines demonstrated complete differentiation capacity. This line, YBLi004-A, is available and registered in the human pluripotent stem cell registry. The line's legitimacy was validated using pluripotent marker expression, in vitro differentiation into three germ layers (ectoderm, mesoderm, and endoderm), karyotyping, and STR analysis. This iPSC line could be used as a healthy control for studies involving disease-specific-iPSCs, e.g. drug toxicity and efficacy testing.

An engineered ligand-responsive Csy4 endoribonuclease controls transgene expression from Sendai virus vectors

BackgroundViral vectors are attractive gene delivery vehicles because of their broad tropism, high transduction efficiency, and durable expression. With no risk of integration into the host genome, the vectors developed from RNA viruses such as Sendai virus (SeV) are especially promising. However, RNA-based vectors have limited applicability because they lack a convenient method to control transgene expression by an external inducer.ResultsWe engineered a Csy4 switch in Sendai virus-based vectors by combining Csy4 endoribonuclease with mutant FKBP12 (DD: destabilizing domain) that becomes stabilized when a small chemical Shield1 is supplied. In this Shield1-responsive Csy4 (SrC) switch, Shield1 increases Csy4 fused with DD (DD-Csy4), which then cleaves and downregulates the transgene mRNA containing the Csy4 recognition sequence (Csy4RS). Moreover, when Csy4RS is inserted in the viral L gene, the SrC switch suppresses replication and transcription of the SeV vector in infected cells in a Shield1-dependent manner, thus enabling complete elimination of the vector from the cells. By temporally controlling BRN4 expression, a BRN4-expressing SeV vector equipped with the SrC switch achieves efficient, stepwise differentiation of embryonic stem cells into neural stem cells, and then into astrocytes.ConclusionSeV-based vectors with the SrC switch should find wide applications in stem cell research, regenerative medicine, and gene therapy, especially when precise control of reprogramming factor expression is desirable.

Generation of iPSCs Using Sendai Virus Vectors.

Induced pluripotent stem cells (iPSCs) are in vitro-derived cells capable of giving rise to several different cell types. The generation of iPSCs holds great promise for regenerative medicine and drug discovery research because it allows mature cells to be reprogrammed into a state of pluripotency. These highly versatile cells can then be induced to produce a variety of cell lineages and tissues by activating specific regulatory genes that drive their differentiation along distinct lineages. The great potential of these cells was recognized by Shinya Yamanaka who was awarded the 2012 Nobel Prize for the discovery of iPSCs. Following their discovery, various methods have now been developed for generating iPSCs. Here, we describe a method for deriving iPSCs from human dental pulp using Sendai virus vectors.

Generation of canine induced pluripotent stem cells under feeder-free conditions using Sendai virus vector encoding six canine reprogramming factors

Although it is in its early stages, canine induced pluripotent stem cells (ciPSCs) hold great potential for innovative translational research in regenerative medicine, developmental biology, drug screening, and disease modeling. However, almost all ciPSCs were generated from fibroblasts, and available canine cell sources for reprogramming are still limited. Furthermore, no report is available to generate ciPSCs under feeder-free conditions because of their low reprogramming efficiency. Here, we reanalyzed canine pluripotency-associated genes and designed canine LIN28A, NANOG, OCT3/4, SOX2, KLF4, and C-MYC encoding Sendai virus vector, called 159cf. and 162cf. We demonstrated that not only canine fibroblasts but also canine urine-derived cells, which can be isolated using a noninvasive and straightforward method, were successfully reprogrammed with or without feeder cells. ciPSCs existed in undifferentiated states, differentiating into the three germ layers invitro and invivo. We successfully generated ciPSCs under feeder-free conditions, which can promote studies in veterinary and consequently human regenerative medicines.

Unraveling Tumorigenicity in iPSC-Derived Immune Cells: The Impact of Chromosomal Abnormalities and Proliferative Intermediates

Response to tumor cells by the immune system can determine the course of a cancer. This guiding principle and the dynamic, adaptable nature of our immune system underlies the drive to generate immune cells for cancer immunotherapy. Induced pluripotent stem cells (iPSCs) provide an unlimited resource for the generation of immune cells such as T cells and dendritic cells (DCs) for cancer immunotherapy. However, the use of iPSC-derived immune cells in clinical applications has been limited due to concerns of safety. In vitro passage of iPSCs can introduce selective pressures that promote the accumulation of mutations that confer a growth advantage. Over several passages, this can lead to the acquisition of chromosomal abnormalities. Moreover, differentiation protocols of varying efficiency permit the presence of immature cells, contaminating the differentiated cell population. However, the impact of chromosomal abnormalities and intermediate products with proliferation potential on tumorigenicity of iPSC-derived immune cells remains unclear. Here, we investigated the tumorigenic potential of iPSC-derived T cells and DCs in immunocompetent and immunodeficient mice. Pmel-1 T-cell receptor (TCR) transgenic mouse T cells were reprogrammed using Sendai virus vectors carrying Oct3/4, Sox2, Klf4 and cMyc. While our iPSCs were phenotypically normal, even at early passage numbers, various chromosomal abnormalities were found in the resulting cell population. These abnormalities included trisomy 8 and 11 and loss of X chromosome with high frequency. Furthermore, within a population of iPSCs determined to be karyotypically normal by G-banding, unbalanced translocations were found by spectral karyotyping. These findings are consistent with those reported in the literature and highlight the prevalence of chromosomal abnormalities in iPSC populations. As iPSCs can harbor chromosomal abnormalities that are undetectable by standard methods, we assessed the tumorigenic potential of iPSC-derived cells, similar to what may be used in clinical applications. Mouse iPSCs were differentiated into CD8αβ T cells by co-culture with murine OP9 bone marrow stromal cells expressing the Notch ligand Delta-like 1 (OP9-DL1) and were enriched by CD8 positive selection. Activated iPSC-derived T cells were adoptively transferred to immunocompetent C57BL/6 and immunodeficient NOD/SCID, IL-2 receptor γ chain knockout mice. Immunodeficient but not immunocompetent mice developed hepatic tumors. Reverse transcription (RT)-PCR identified Pme1-l TCR gene in tumor cells, confirming tumor origin. Moreover, histology of liver tumors is suggestive of lymphoma or lymphosarcoma. Within the population of CD8+ iPSC-derived cells, a small subpopulation co-expressing CD8 and SSEA-1 was present. Sorting the cells by SSEA-1 positivity eliminated tumor formation in vivo. Mouse iPSCs were also differentiated into DCs by co-culture with OP9-DL1 cells and granulocyte macrophage colony-stimulating factor. Despite similar use of iPSCs with chromosomal abnormalities and prolonged passaging in vitro, SSEA-1+ cells were not identified when they were differentiated to DCs, and iPSC-derived DCs did not form tumors in immunodeficient mice. Taken together, this study revealed the potential risk of tumorigenicity of iPSC-derived immune cells in our preclinical model. The presence of chromosomal abnormalities did not definitively determine risk of tumorigenesis upon transplantation. The relationship between SSEA-1 positivity and tumor formation suggests contaminating cells may carry tumorigenic characteristics. Further work is required to develop differentiation methods that generate pure populations, free of tumorigenic intermediates, to potentiate the clinical use of iPSC-derived immunotherapy.

IPSC-Derived Dual Antigen Receptor T Cells Targeting GD2 and LMP2 Antigens for Extranodal NK/T-Cell Lymphoma, Nasal Type

Epstein-Barr virus (EBV)-associated lymphomas generally exhibit poor prognosis. Given that EBV antigens, LMP1 and LMP2, are often expressed on EBV-associated lymphomas, these lymphomas should be a good target of antigen-specific cytotoxic T lymphocytes (CTL) therapy. Among these, advanced-stage ENKL is a highly aggressive disease. We previously reported that functionally rejuvenated LMP2-specific CTLs (LMP2-rejTs), generated from induced pluripotent stem cells (iPSCs), robustly suppress ENKL in vivo with remarkable persistence for more than seven months. To mitigate the risk of tumor antigen escape, we next generated dual-antigen receptor rejuvenated T cells from iPSCs by introduction of LMP1-directed chimeric antigen receptor (CAR) into LMP2-rejTs which have already demonstrated in vivo persistence. We reported that these cells recognize dual antigens via CAR and native T cell receptor, resulting in cooperative antitumor effects in vivo. We have recently confirmed that ENKL cells often express disialoganglioside (GD2). GD2 has been identified as a promising target for CAR T-cell therapy aimed at GD2-expressing tumors. A number of Phase 1 clinical trials, utilizing GD2-directed CAR (GD2-CAR) T-cell therapy in neuroblastoma patients, have demonstrated not only safety but also efficient in vivo expansion, all while avoiding significant toxicities. For clinical implementation, we have developed iPSC-derived dual antigen receptor T cells, where we incorporated GD2-CAR into LMP2-rejTs, resulting in GD2-CARrejTs. We reprogrammed an LMP2-CTL clone derived from a healthy donor into iPSCs using a Sendai virus vector, followed by transduction with the lentiviral GD2-CAR vector. Utilizing flow cytometry, we evaluated CAR transgene expression in the GD2-CARrejTs and found a substantial expression rate of 91.8%. Additionally, we determined a nearly perfect LMP2 antigen specificity of 99.9% for the GD2-CARrejTs, also measured by flow cytometry. To investigate whether GD2-CARrejTs exhibited cytotoxicity against ENKL than GD2-CARTs, we performed 51Cr release assays. The cytotoxicity of GD2-CARrejTs was significantly stronger against an ENKL cell line (NK-YS), than that of GD2-CARTs (79.8% vs 24.8%; p < 0.0001) at an effector to target ratio of 40:1. Next, to observe the in vivo antitumor effect of GD2-CARrejTs against NK-YS, NK-YS cells labeled with Firefly luciferase / GFP were intraperitoneally injected into NOG mice. Four days after tumor injection, mice were divided into untreated (control) and treated (GD2-CARrejTs) groups. Tumor signal was significantly suppressed in mice treated with GD2-CARrejTs compared to untreated mice on Day 35 ( p = 0.0318). To delineate the disparities in cytotoxicity, we undertook a single-cell RNA sequencing analysis and confirmed that GD2-CARrejTs exhibited significantly lower TIGIT expression in comparison to GD2-CAR T cells. In fact, we noted an amplification of the cytotoxic impact of GD2-CAR T cells when paired with TIGIT antibodies against GD2-expressing tumor cells. However, the enhanced cytotoxicity still did not exceed that of GD2-CARrejTs. From these results, we conclude that GD2-CARrejTs may constitute a promising therapeutic approach against refractory ENKL. The most significant advantage of iPSC-derived T cell therapy lies in its clonality and potential for an unlimited supply of therapeutic T cells. Additional gene-editing of iPSC-derived CARrejT cells could potentially lay the groundwork for allogeneic, “off-the-shelf” GD2-CARrejT therapy, thereby introducing a promising new therapeutic avenue for patients with ENKL in the foreseeable future.

A Protocol for Culture and Characterization of Human Induced Pluripotent Stem Cells After Induction.

Human induced pluripotent stem cells (hiPSCs) are characterized by unlimited self-renewal and the capability to differentiate into all three germ layers, with the potential to further differentiate into all types of cells and tissues. Human iPSCs retain all genetic information from their original donors and can be developed into disease models to study disease pathophysiology, identify disease phenotypes and biomarkers, and evaluate therapeutic efficacy and toxicity for drug development. Human iPSCs can also be used to develop cell therapies and regenerative medicine. In the last decade, the technologies for hiPSC generation and differentiation have advanced rapidly. Human iPSC culture and propagation are tedious and require careful handling. High-quality hiPSCs are necessary for downstream applications. The methods, techniques, and skills for hiPSC maintenance and characterization are very different from those for immortalized cell lines. It can be a challenge for new laboratory staff, and sometimes even for experienced staff, to properly culture and maintain the high quality of these cells. Here, we describe a comprehensive set of protocols for hiPSC propagation under chemically defined and feeder-free culture conditions. These step-by-step protocols describe in detail all the reagents and experimental procedures needed to culture hiPSCs. The protocols also describe experimental methods for hiPSC characterization, including immunofluorescence staining and flow cytometric analysis with a panel of pluripotency markers, a teratoma formation assay for validation of in vivo pluripotency, and detection of Sendai virus to ensure elimination of the viral vectors. These protocols have been successfully used in our laboratory for hiPSC expansion and propagation, and this article provide a useful reference guide for laboratory staff to work on hiPSC culture. Published 2023. This article is a U.S. Government work and is in the public domain in the USA. Current Protocols published by Wiley Periodicals LLC. Basic Protocol 1: Propagation and cryopreservation of hiPSC cultures Basic Protocol 2: Recovery of cryopreserved hiPSCs Basic Protocol 3: Validation of pluripotency markers via immunocytochemical analysis Alternate Protocol: Determination of the expression of pluripotency markers via flow cytometry analysis Basic Protocol 4: Assessment of pluripotency via in vivo teratoma formation assay Basic Protocol 5: Confirmation of Sendai viral vector clearance via RT-PCR.

Generation and Maintenance of Primate Induced Pluripotent Stem Cells Derived from Urine.

Cross-species approaches studying primate pluripotent stem cells and their derivatives are crucial to better understand the molecular and cellular mechanisms of disease, development, and evolution. To make primate induced pluripotent stem cells (iPSCs) more accessible, this paper presents a non-invasive method to generate human and non-human primate iPSCs from urine-derived cells, and their maintenance using a feeder-free culturing method. The urine can be sampled from a non-sterile environment (e.g., the cage of the animal) and treated with a broad-spectrum antibiotic cocktail during primary cell culture to reduce contamination efficiently. After propagation of the urine-derived cells, iPSCs are generated by a modified transduction method of a commercially available Sendai virus vector system. FirstiPSC colonies may already be visible after 5 days, and can be picked after 10 days at the earliest. Routine clump passaging with enzyme-free dissociation buffer supports pluripotency of the generated iPSCs for more than 50 passages.

Abstract 1214: Establishment and characterization of reversibly immortalized endometrial and ovarian epithelial cell lines using Sendai virus

Abstract Objective: We aimed to establish reversibly immortalized cell lines from human uterine and ovary cells using the Sendai virus (SeV) vector. The immortalized cells derive from normal and benign ovarian epithelial cells and endometrial epithelial cells. Furthermore, we sought to elucidate the mechanisms of carcinogenesis using the immortalized cell lines. Methods: Cells were collected at the time of surgery after obtaining patient consent. The cells used in this study were as follows: ovarian epithelial cells (normal epithelium, Ov n; normal epithelium with germline BRCA1 or BRCA2 mutation, Ov BRCA1 2; ovarian endometrioma, Ov endo; mucinous cystadenoma; Ov m), normal fallopian tube (FT) cells, and endometrial epithelium (normal epithelium, Em n). These cells were infected with temperature-sensitive SeV vectors carrying three immortalization genes, Bmi-1, hTERT, and SV40T.The presence of infection was confirmed through Green Fluorescent Protein (GFP) and Orange Fluorescent Protein (OFP). Immunoreactivity to the anti-human EpCAM antibody (a marker derived from epithelial carcinoma) in each SeV-infected cell was confirmed through flow cytometry. QH and multicolor FISH staining were performed for karyotyping of metaphase chromosomes in each cell line to determine chromosome number and structural abnormalities. Human transcriptome sequencing analysis was performed with NovaSeq 6000 (Illumina) using total RNA from each cell line. Some genes that showed significant expression in each cell line were subjected to real-time PCR (RT-PCR). Results: We established the immortalized cell lines from human uterine and ovarian tissues. SeV-infected cells exhibited GFP and OFP fluorescence, while non-infected cells did not. SeV infection allowed all primary cell lines to grow for 25 or more passages, while non-infected SeV cells lacked the proliferative capacity and showed senescence-like morphology. SeV-infected cells senesced in a temperature-dependent manner. Ov n SeV- infected cells ion causedshowed a small increase in chromosome structural abnormalities. But, Ov BRCA1 and 2 SeV-infected cells showed larger than thatand . Llong-term passaged cells did not show immune response to anti-human EpCAM antibodies in normal cells. Eleven Three genes were predominantly expressed in Ov BRCA1 and Ov BRCA2 cells and were not expressed in Ov n cells. SomeTwo out of ththe three genesem were found to be predominantly expressed in Ov endo cells compared to the expression in the Ovn cell line. Furthermore, RT-PCR results also indicated substantially higher expression of two genes in Ov BRCA1/2 cells and in Ov endo cells compared to the expression in Ov n cells. Conclusion: We succeeded in the reversible immortalization of endometrial and ovarian epithelial cells by using SeV infection. We identified several candidate genes that may be involved in the oncogenic mechanism of ovarian cancer associated with endometriosis or germline BRCA1 and BRCA2. Citation Format: Masayo Okawa, Hiroaki Komatsu, Kohei Hikino, Yuki Iida, Masayo Hosokawa, Mayumi Sawada, Akiko Kudoh, Jun Chikumi, Shinya Sato, Genki Hichiwa, Yasuhiro Kazuki, Kanako Kazuki, Fuminori Taniguchi, Mitsuo Oshimura, Tasuku Harada. Establishment and characterization of reversibly immortalized endometrial and ovarian epithelial cell lines using Sendai virus [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 1214.

Preferential Hematopoietic Differentiation in Induced Pluripotent Stem Cells Derived From Human Umbilical Cord Arterial Endothelial Cells.

The major obstacle for applications of human induced pluripotent stem cells (hiPSCs) is efficient and controlled lineage-specific differentiation. Hence, a deeper understanding of the initial populations of hiPSCs is required to instruct proficient lineage commitment. hiPSCs were generated from somatic cells by transduction of 4 human transcription factors (OCT4, SOX2, KLF4, and C-MYC) using Sendai virus vectors. Genome-wide DNA methylation analysis and transcriptional analysis were performed to evaluate the pluripotent capacity and somatic memory state of hiPSCs. Flow cytometric analysis and colony assays were performed to assess the hematopoietic differentiation capacity of hiPSCs. Here, we reveal human umbilical arterial endothelial cell-derived induced pluripotent stem cells (HuA-iPSCs) exhibit indistinguishable pluripotency in comparison with human embryonic stem cells and hiPSCs derived from other tissues of origin (umbilical vein endothelial cells, cord blood, foreskin fibroblasts, and fetal skin fibroblasts). However, HuA-iPSCs retain a transcriptional memory typical of the parental human umbilical cord arterial endothelial cells, together with a strikingly similar DNA methylation signature to umbilical cord blood-derived induced pluripotent stem cells that distinguishes them from other human pluripotent stem cells. Ultimately, HuA-iPSCs are most efficient in targeted differentiation toward hematopoietic lineage among all human pluripotent stem cells based on the functional and quantitative evaluation of both flow cytometric analysis and colony assays. Application of the Rho-kinase activator significantly reduces the effects of preferential hematopoietic differentiation in HuA-iPSCs, reflected in CD34+ cell percentage of day 7, hematopoietic/endothelial-associated gene expression, and even colony-forming unit numbers. Collectively, our data suggest that somatic cell memory may predispose HuA-iPSCs to differentiate more amenably into hematopoietic fate, bringing us closer to generating hematopoietic cell types in vitro from nonhematopoietic tissue for therapeutic applications.

Generation of integration-free Down syndrome and isogenic euploid human induced pluripotent stem cells

A pair of Down syndrome (DS) human iPSCs (hiPSCs) and isogenic euploid hiPSCs generated by using an integration-free Sendai viral vector system showed trisomy 21 (47; XY) and typical (46; XY) karyotype respectively. Pluripotency of both hiPSC lines was confirmed by pluripotency marker expression and three germ layer differentiation potentials.

Generation of mesenchymal stromal cells from urine-derived iPSCs of pediatric brain tumor patients.

Human induced pluripotent stem cells (iPSCs) provide a virtually inexhaustible source of starting material for next generation cell therapies, offering new opportunities for regenerative medicine. Among different cell sources for the generation of iPSCs, urine cells are clinically relevant since these cells can be repeatedly obtained by non-invasive methods from patients of any age and health condition. These attributes encourage patients to participate in preclinical and clinical research. In particular, the use of urine-derived iPSC products is a convenient strategy for children with brain tumors, which are medically fragile patients. Here, we investigate the feasibility of using urine samples as a source of somatic cells to generate iPSC lines from pediatric patients with brain tumors (BT-iPSC). Urinary epithelial cells were isolated and reprogrammed using non-integrative Sendai virus vectors harboring the Yamanaka factors KLF4, OCT3/4, SOX2 and C-MYC. After reprogramming, BT-iPSC lines were subject to quality assessment and were compared to iPSCs obtained from urine samples of non-tumor pediatric patients (nonT-iPSC). We demonstrated that iPSCs can be successfully derived from a small volume of urine obtained from pediatric patients. Importantly, we showed that BT-iPSCs are equivalent to nonT-iPSCs in terms of morphology, pluripotency, and differentiation capacity into the three germ layers. In addition, both BT-iPSCs and nonT-iPSCs efficiently differentiated into functional mesenchymal stem/stromal cells (iMSC) with immunomodulatory properties. Therefore, this study provides an attractive approach to non-invasively generate personalized iMSC products intended for the treatment of children with brain tumors.

Derivation of Sendai-Virus-Reprogrammed Human iPSCs-Neuronal Precursors: In Vitro and In Vivo Post-grafting Safety Characterization

The critical requirements in developing clinical-grade human-induced pluripotent stem cells–derived neural precursors (hiPSCs-NPCs) are defined by expandability, genetic stability, predictable in vivo post-grafting differentiation, and acceptable safety profile. Here, we report on the use of manual-selection protocol for generating expandable and stable human NPCs from induced pluripotent stem cells. The hiPSCs were generated by the reprogramming of peripheral blood mononuclear cells with Sendai-virus (SeV) vector encoding Yamanaka factors. After induction of neural rosettes, morphologically defined NPC colonies were manually harvested, re-plated, and expanded for up to 20 passages. Established NPCs showed normal karyotype, expression of typical NPCs markers at the proliferative stage, and ability to generate functional, calcium oscillating GABAergic or glutamatergic neurons after in vitro differentiation. Grafted NPCs into the striatum or spinal cord of immunodeficient rats showed progressive maturation and expression of early and late human-specific neuronal and glial markers at 2 or 6 months post-grafting. No tumor formation was seen in NPCs-grafted brain or spinal cord samples. These data demonstrate the effective use of in vitro manual-selection protocol to generate safe and expandable NPCs from hiPSCs cells. This protocol has the potential to be used to generate GMP (Good Manufacturing Practice)-grade NPCs from hiPSCs for future clinical use.

Migration deficits of the neural crest caused by CXADR triplication in a human Down syndrome stem cell model

Down syndrome (DS) is the most common chromosomal abnormality in live-born infants and is caused by trisomy of chromosome 21. Most individuals with DS display craniofacial dysmorphology, including reduced sizes of the skull, maxilla, and mandible. However, the underlying pathogenesis remains largely unknown. Since the craniofacial skeleton is mainly formed by the neural crest, whether neural crest developmental defects are involved in the craniofacial anomalies of individuals with DS needs to be investigated. Here, we successfully derived DS-specific human induced pluripotent stem cells (hiPSCs) using a Sendai virus vector. When DS-hiPSCs were induced to differentiate into the neural crest, we found that trisomy 21 (T21) did not influence cell proliferation or apoptosis. However, the migratory ability of differentiated cells was significantly compromised, thus resulting in a substantially lower number of postmigratory cranial neural crest stem cells (NCSCs) in the DS group than in the control group. We further discovered that the migration defects could be partially attributed to the triplication of the coxsackievirus and adenovirus receptor gene (CXADR; an adhesion protein) in the DS group cells, since knockdown of CXADR substantially recovered the cell migratory ability and generation of postmigratory NCSCs in the DS group. Thus, the migratory deficits of neural crest cells may be an underlying cause of craniofacial dysmorphology in individuals with DS, which may suggest potential targets for therapeutic intervention to ameliorate craniofacial or other neural crest-related anomalies in DS.