In vivo reprogrammed pluripotent stem cells from teratomas share analogous properties with their in vitro counterparts.
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ABSTRACT:
SUBMITTER: Choi HW
PROVIDER: S-EPMC4551988 | biostudies-literature |
REPOSITORIES: biostudies-literature
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Project description:BackgroundPluripotent stem cells (PSCs) offer immense potential as a source for regenerative therapies. The teratoma assay is widely used in the field of stem cells and regenerative medicine, but the cell composition of teratoma is still elusive.MethodsWe utilized PSCs expressing enhanced green fluorescent protein (EGFP) under the control of the Pou5f1 promoter to study the persistence of potential pluripotent cells during teratoma formation in vivo. OCT4-MES (mouse embryonic stem cells) were isolated from the blastocysts of 3.5-day OCT4-EGFP mice (transgenic mice express EGFP cDNA under the control of the Pou5f1 promoter) embryos, and TG iPS 1-7 (induced pluripotent stem cells) were generated from mouse embryonic fibroblasts (MEFs) from 13.5-day OCT4-EGFP mice embryos by infecting them with a virus carrying OCT4, SOX2, KLF4 and c-MYC. These pluripotent cells were characterized according to their morphology and expression of pluripotency markers. Their differentiation ability was studied with in vivo teratoma formation assays. Further differences between pluripotent cells were examined by real-time quantitative PCR (qPCR).ResultsThe results showed that several OCT4-expressing PSCs escaped differentiation inside of teratomas, and these escaped cells (MES-FT, GFP-positive cells separated from OCT4-MES-derived teratomas; and iPS-FT, GFP-positive cells obtained from teratomas formed by TG iPS 1-7) retained their pluripotency. Interestingly, a small number of GFP-positive cells in teratomas formed by MES-FT and iPS-FT (MES-ST, GFP-positive cells isolated from MES-FT-derived teratomas; iPS-ST, GFP-positive cells obtained from teratomas formed by iPS-FT) were still pluripotent, as shown by alkaline phosphatase (AP) staining, immunofluorescent staining and PCR. MES-FT, iPS-FT, MES-ST and iPS-ST cells also expressed several markers associated with germ cell formation, such as Dazl, Stella and Stra8.ConclusionsIn summary, a small number of PSCs escaped differentiation inside of teratomas, and these cells maintained pluripotency and partially developed towards germ cells. Both escaped PSCs and germ cells present a risk of tumor formation. Therefore, medical workers must be careful in preventing tumor formation when stem cells are used to treat specific diseases.
| S-EPMC5756617 | biostudies-literature
Project description:Human pluripotent stem cells have the ability to generate all cell types present in the adult organism, therefore harboring great potential for the in vitro study of differentiation and for the development of cell-based therapies. Nonetheless their use may prove challenging as incomplete differentiation of these cells might lead to tumoregenicity. Interestingly, many cancer types have been reported to display metabolic modifications with features that might be similar to stem cells. Understanding the metabolic properties of human pluripotent stem cells when compared to their differentiated counterparts can thus be of crucial importance. Furthermore recent data has stressed distinct features of different human pluripotent cells lines, namely when comparing embryo-derived human embryonic stem cells (hESCs) and induced pluripotent stem cells (IPSCs) reprogrammed from somatic cells.We compared the energy metabolism of hESCs, IPSCs, and their somatic counterparts. Focusing on mitochondria, we tracked organelle localization and morphology. Furthermore we performed gene expression analysis of several pathways related to the glucose metabolism, including glycolysis, the pentose phosphate pathway and the tricarboxylic acid (TCA) cycle. In addition we determined oxygen consumption rates (OCR) using a metabolic extracellular flux analyzer, as well as total intracellular ATP levels by high performance liquid chromatography (HPLC). Finally we explored the expression of key proteins involved in the regulation of glucose metabolism.Our results demonstrate that, although the metabolic signature of IPSCs is not identical to that of hESCs, nonetheless they cluster with hESCs rather than with their somatic counterparts. ATP levels, lactate production and OCR revealed that human pluripotent cells rely mostly on glycolysis to meet their energy demands. Furthermore, our work points to some of the strategies which human pluripotent stem cells may use to maintain high glycolytic rates, such as high levels of hexokinase II and inactive pyruvate dehydrogenase (PDH).
| S-EPMC3117868 | biostudies-literature
Project description:Pluripotent stem cells can be easily differentiated in vitro into a certain lineage through embryoid body formation. Recently, however, we reported partially reprogrammed cells showing some pluripotent characteristics, which failed to differentiate in vitro. Here, we attempted to generate neural stem cells (NSCs) from partially reprogrammed cells using an in vivo differentiation system involving teratoma formation. Partially reprogrammed cells formed teratomas after injection into immunocompromised mice, and NSCs could be isolated from these teratomas. These in vivo NSCs expressed NSC markers and terminally differentiated into neurons and glial cells. Moreover, these NSCs exhibited molecular profiles very similar to those of brain-derived NSCs. These results suggest that partially reprogrammed cells defective in in vitro differentiation ability can differentiate into pure populations of NSCs through an in vivo system.
| S-EPMC5369976 | biostudies-literature
Project description:The safe utilization of induced pluripotent stem cell (iPSC) derivatives in clinical use is attributed to the complete elimination of the risk of forming teratomas after transplantation. The extent by which such a risk exists in immune-competent hosts is mostly unknown. Here, using humanized mice reconstituted with fetal hematopoietic stem cells and autologous thymus tissue (bone-liver-thymus humanized mice [Hu-BLT]) or following the adoptive transfer of peripheral blood mononuclear cells(PBMCs) (Hu-AT), we evaluated the capacity of immune cells to prevent or eliminate teratomas derived from human iPSCs (hiPSCs). Our results showed that the injection of hiPSCs failed to form teratomas in Hu-AT mice reconstituted with allogeneic or autologous PBMCs or purified natural killer (NK) cells alone. However, teratomas were observed in Hu-AT mice reconstituted with autologous PBMCs depleted from NK cells. In line with these results, Hu-BLT, which do not have functional NK cells, could not prevent the growth of teratomas. Finally, we found that established teratomas were not targeted by NK cells and instead were efficiently rejected by allogeneic but not autologous T cells in Hu-AT mice. Overall, our findings suggest that autologous hiPSC-derived therapies are unlikely to form teratomas in the presence of NK cells.
| S-EPMC6854018 | biostudies-literature
Project description:Teratoma formation is the gold standard assay for testing the capacity of human pluripotent stem cells to differentiate into all embryonic germ layers. Although widely used, little effort has been made to transform this qualitative assay into a quantitative one. Using gene expression data from a wide variety of cells, we created a scorecard representing tissues from all germ layers and extraembryonic tissues. TeratoScore, an online, open-source platform based on this scorecard, distinguishes pluripotent stem cell-derived teratomas from malignant tumors, translating cell potency into a quantitative measure (http://benvenisty.huji.ac.il/teratoscore.php). The teratomas used for the algorithm also allowed us to examine gene expression differences between tumors with a diploid karyotype and those initiated by aneuploid cells. Chromosomally aberrant teratomas show a significantly different gene expression signature from that of teratomas originating from diploid cells, particularly in central nervous system-specific genes, congruent with human chromosomal syndromes.
| S-EPMC4471824 | biostudies-other
Project description:Human pluripotent stem cells, including human embryonic stem cells (hESCs) and human induced PSCs (hiPSCs), have great potential as an unlimited donor source for cell-based therapeutics. The risk of teratoma formation from residual undifferentiated cells, however, remains a critical barrier to the clinical application of these cells. Herein, we describe external beam radiation therapy (EBRT) as an attractive option for the treatment of this iatrogenic growth. We present evidence that EBRT is effective in arresting growth of hESC-derived teratomas in vivo at day 28 post-implantation by using a microCT irradiator capable of targeted treatment in small animals. Within several days of irradiation, teratomas derived from injection of undifferentiated hESCs and hiPSCs demonstrated complete growth arrest lasting several months. In addition, EBRT reduced reseeding potential of teratoma cells during serial transplantation experiments, requiring irradiated teratomas to be seeded at 1 × 103 higher doses to form new teratomas. We demonstrate that irradiation induces teratoma cell apoptosis, senescence, and growth arrest, similar to established radiobiology mechanisms. Taken together, these results provide proof of concept for the use of EBRT in the treatment of existing teratomas and highlight a strategy to increase the safety of stem cell-based therapies. Stem Cells 2017;35:1994-2000.
| S-EPMC5568072 | biostudies-literature
Project description:Generation of patient-specific induced pluripotent cells (iPSCs) holds great promise for regenerative medicine. Epstein-Barr virus immortalized lymphoblastoid B-cell lines (LCLs) can be generated from a minimal amount of blood and are banked worldwide as cellular reference material for immunologic or genetic analysis of pedigreed study populations. We report the generation of iPSCs from 2 LCLs (LCL-iPSCs) via a feeder-free episomal method using a cocktail of transcription factors and small molecules. LCL-derived iPSCs exhibited normal karyotype, expressed pluripotency markers, lost oriP/EBNA-1 episomal vectors, generated teratomas, retained donor identity, and differentiated in vitro into hematopoietic, cardiac, neural, and hepatocyte-like lineages. Significantly, although the parental LCLs express viral EBNA-1 and other Epstein-Barr virus latency-related elements for their survival, their presence was not detectable in LCL-iPSCs. Thus, reprogramming LCLs could offer an unlimited source for patient-specific iPSCs.
| S-EPMC4081297 | biostudies-literature
Project description:In vitro cardiac differentiation can be readily achieved in human induced pluripotent stem cells (hiPSCs) via temporal modulation of Wnt signalling. However, its differentiation trajectory and the in vivo counterpart of intermediate progenitor populations has yet to be elucidated. This study aims to capture the most diverse amount of distinct cell populations during in vitro cardiac differentiation by performing single cell RNA-sequencing at day 2, 4, 5 and 9 cells undergoing in vitro cardiac differentiation. Our study has revealed in vitro cardiac differentiation is analogous with in vivo second heart field cell specification.
2023-08-17 | GSE174213 | GEO
Project description:The use of cells derived from pluripotent stem cells (PSCs) for regenerative therapies confers a considerable risk for neoplastic growth and teratoma formation. Preclinical and clinical assessment of such therapies will require suitable monitoring strategies to understand and mitigate these risks. Here we generated human-induced pluripotent stem cells (iPSCs), selected clones that continued to express reprogramming factors after differentiation into cardiomyocytes, and transplanted these cardiomyocytes into immunocompromised rat hearts post-myocardial infarction. We compared magnetic resonance imaging (MRI), cardiac ultrasound, and serum biomarkers for their ability to delineate teratoma formation and growth. MRI enabled the detection of teratomas with a volume >8 mm(3). A combination of three plasma biomarkers (CEA, AFP, and HCG) was able to detect teratomas with a volume >17 mm(3) and with a sensitivity of more than 87%. Based on our findings, a combination of serum biomarkers with MRI screening may offer the highest sensitivity for teratoma detection and tracking.
| S-EPMC4750097 | biostudies-literature
Project description:Genetically unmodified cardiomyocytes mandated for cardiac regenerative therapy is conceivable by "foot-print free" reprogramming of somatic cells to induced pluripotent stem cells (iPSC). In this study, we report generation of foot-print free hiPSC through messenger RNA (mRNA) based reprograming. Subsequently, we characterize cardiomyocytes derived from these hiPSC using molecular and electrophysiological methods to characterize their applicability for regenerative medicine. Our results demonstrate that mRNA-iPSCs differentiate ontogenetically into cardiomyocytes with increased expression of early commitment markers of mesoderm, cardiac mesoderm, followed by cardiac specific transcriptional and sarcomeric structural and ion channel genes. Furthermore, these cardiomyocytes stained positively for sarcomeric and ion channel proteins. Based on multi-electrode array (MEA) recordings, these mRNA-hiPSC derived cardiomyocytes responded predictably to various pharmacologically active drugs that target adrenergic, sodium, calcium and potassium channels. The cardiomyocytes responded chronotropically to isoproterenol in a dose dependent manner, inotropic activity of nifidipine decreased spontaneous contractions. Moreover, Sotalol and E-4031 prolonged QT intervals, while TTX reduced sodium influx. Our results for the first time show a systemic evaluation based on molecular, structural and functional properties of cardiomyocytes differentiated from mRNA-iPSC. These results, coupled with feasibility of generating patient-specific iPSCs hold great promise for the development of large-scale generation of clinical grade cardiomyocytes for cardiac regenerative medicine.
| S-EPMC4113436 | biostudies-literature