Generation of human induced pluripotent stem cell lines from human dermal fibroblasts using a non-integration system

Therapeutic potential of mesenchymal stem cells from human iPSC-derived teratomas for osteochondral defect regeneration

Human induced pluripotent stem cells (iPSCs) hold great promise for personalized medicine, as they can be differentiated into specific cell types, especially mesenchymal stem cells (MSCs). Therefore, our study sought to assess the feasibility of deriving MSCs from teratomas generated from human iPSCs. Teratomas serve as a model to mimic multilineage human development, thus enriching specific somatic progenitors and stem cells. Here, we discovered a small, condensed mass of MSCs within iPSC-generated teratomas. Afterward, we successfully isolated MSCs from this condensed mass, which was a byproduct of teratoma development. To evaluate the characteristics and cell behaviors of iPSC-derived MSCs (iPSC-MSCs), we conducted comprehensive assessments using qPCR, immunophenotype analysis, and cell proliferation-related assays. Remarkably, iPSC-MSCs exhibited an immunophenotype resembling that of conventional MSCs, and they displayed robust proliferative capabilities, similar to those of higher pluripotent stem cell-derived MSCs. Furthermore, iPSC-MSCs demonstrated the ability to differentiate into multiple lineages in vitro. Finally, we evaluated the therapeutic potential of iPSC-MSCs using an osteochondral defect model. Our findings demonstrated that teratomas are a promising source for the isolation of condensed MSCs. More importantly, our results suggest that iPSC-MSCs derived from teratomas possess the capacity for tissue regeneration, highlighting their promise for future therapeutic applications.

DUSP6 is a memory retention feedback regulator of ERK signaling for cellular resilience of human pluripotent stem cells in response to dissociation

Cultured human pluripotent stem cells (hPSCs) grow as colonies that require breakdown into small clumps for further propagation. Although cell death mechanism by single-cell dissociation of hPSCs has been well defined, how hPSCs respond to the deadly stimulus and recover the original status remains unclear. Here we show that dissociation of hPSCs immediately activates ERK, which subsequently activates RSK and induces DUSP6, an ERK-specific phosphatase. Although the activation is transient, DUSP6 expression persists days after passaging. DUSP6 depletion using the CRISPR/Cas9 system reveals that DUSP6 suppresses the ERK activity over the long term. Elevated ERK activity by DUSP6 depletion increases both viability of hPSCs after single-cell dissociation and differentiation propensity towards mesoderm and endoderm lineages. These findings provide new insights into how hPSCs respond to dissociation in order to maintain pluripotency.

Functional in vivo and in vitro effects of 20q11.21 genetic aberrations on hPSC differentiation

Human pluripotent stem cells (hPSCs) have promising therapeutic applications due to their infinite capacity for self-renewal and pluripotency. Genomic stability is imperative for the clinical use of hPSCs; however, copy number variation (CNV), especially recurrent CNV at 20q11.21, may contribute genomic instability of hPSCs. Furthermore, the effects of CNVs in hPSCs at the whole-transcriptome scale are poorly understood. This study aimed to examine the functional in vivo and in vitro effects of frequently detected CNVs at 20q11.21 during early-stage differentiation of hPSCs. Comprehensive transcriptome profiling of abnormal hPSCs revealed that the differential gene expression patterns had a negative effect on differentiation potential. Transcriptional heterogeneity identified by single-cell RNA sequencing (scRNA-seq) of embryoid bodies from two different isogenic lines of hPSCs revealed alterations in differentiated cell distributions compared with that of normal cells. RNA-seq analysis of 22 teratomas identified several differentially expressed lineage-specific markers in hPSCs with CNVs, consistent with the histological results of the altered ecto/meso/endodermal ratio due to CNVs. Our results suggest that CNV amplification contributes to cell proliferation, apoptosis, and cell fate specification. This work shows the functional consequences of recurrent genetic abnormalities and thereby provides evidence to support the development of cell-based applications.

Transplantation of human urine-derived neural progenitor cells after spinal cord injury in rats

Spinal cord injury (SCI) is a worldwide problem and transplantation of neural progenitor cells (NPCs) represents a promising treatment strategy. Urine derived induced pluripotent stem cells (UiPSCs) which enable the generation of patient-specific NPCs, provide an invaluable source of autologous cells for future therapeutic applications after SCI. However, the fate and potential contribution of transplanted human UiPSCs-derived NPCs (UiPSC-NPCs) into injured spinal cords remain largely unknown. In this study, using a rat contusive SCI model, we evaluated the survival, migration and differentiation of UiPSC-NPCs after transplantation at subacute phase. Transplanted cells survived and migrated from the site of grafting towards the lesion epicenter. More than 25 % cells survived over 4 weeks post transplantation, with a few of them differentiated into neurons and astrocytes. Cytokine and chemokine levels within the injured spinal cord tissues were measured using multiplex immunoassays to evaluate the immune response. Pro-inflammatory factors and chemokines were significantly decreased at 3 days after UiPSC-NPCs transplantation. At 7 days post transplantation, a lower level of pro-inflammatory factor IFN-γ and a higher level of pro-inflammatory IL-2 were found in UiPSC-NPCs group than in the control. Transplantation of UiPSC-NPCs showed little effect on microglia activation at the lesion epicenter. However, the number of microglia cells at 4 mm rostral to the injury site was significantly decreased. The size of lesion cavity was reduced after transplantation of UiPSC-NPCs. In conclusions, the UiPSC-NPCs transplanted at the subacute phase of SCI showed a beneficial effect on tissue repairing.

Generation of a GLA knock-out human-induced pluripotent stem cell line, KSBCi002-A-1, using CRISPR/Cas9

Fabry disease is an X-linked inherited disease caused by a mutation in the galactosidase alpha (GLA) gene. Here, we generated a GLA knock-out cell line (GLA-KO hiPSCs) from normal human-induced pluripotent stem cells (hFSiPS1) using the CRISPR-Cas9 genome-editing tool. The GLA-KO hiPSCs maintained normal morphology, karyotypes, expression of stemness markers, and trilineage differentiation potential. Furthermore, the GLA-KO hiPSCs exhibited dissipation of GLA activity and abnormal Globotriaosylceramide (Gb3) accumulation. Our GLA-KO hiPSC line represents a valuable tool for studying the mechanisms involved in Fabry disease and the development of novel therapeutic alternatives to treat this rare condition.

Simple differentiation method using FBS identifies DUSP6 as a marker for fine-tuning of FGF-ERK signaling activity in human pluripotent stem cells

Assessment of differentiation potential is a basic requirement to obtain qualified human pluripotent stem cells (hPSCs). Here, we report a simple differentiation method using fetal bovine serum (FBS) to estimate differentiation potential and propensity of hPSCs. PluriTest using RNA-sequencing showed that cells differentiated after treatment with 5% FBS. Expression patterns of three germ layer markers revealed that cells cultured in Knockout Serum Replacement-containing medium (KSR) with mouse feeder cells had higher differentiation potential than cells cultured in a chemically defined medium (E8) with recombinant matrix proteins, especially into the mesoderm and endoderm lineages. Analysis of differentially expressed genes between KSR and E8 identified DUSP6 as a marker for where cells had been cultured. Expression of DUSP6 correlated with FGF-ERK signaling activity. Fine-tuning of FGF-ERK signaling activity to a range that can shut down DUSP6 transcription but sustain NANOG transcription partially increased the differentiation potential. Our data suggest that differentiation with 5% FBS is good to estimate differentiation potential and propensity at the early stage, and that DUSP6 is an excellent marker to monitor ERK signaling activity.