Project description:Recent studies demonstrated that fibroblasts could be converted into induced neural stem cells (iNSCs). However, the insertional mutation caused by random integration of viral vectors has been a major limitation of iNSCs for the future clinical translation. Here we show that non-viral transfection of episomal vectors encoding Brn4/Pou3f4, Sox2, Klf4, and c-Myc sufficiently generates iNSCs. The episomal vector mediated iNSCs closely resemble brain-derived NSCs as well as iNSCs generated by retrovirus in morphology, gene expression profile, epigenetic status, self-renewal capacity and both in vitro and in vivo differentiation capacity. The novel conversion protocol defined in the current study offers a method for generating integration-free iNSCs for the clinical research we developed a novel method for generating integration-free iNSCs. We demonstrated that oriP/EBNA1-based episomal vectors could generate iNSCs by single transfection
Project description:Recent studies demonstrated that fibroblasts could be converted into induced neural stem cells (iNSCs). However, the insertional mutation caused by random integration of viral vectors has been a major limitation of iNSCs for the future clinical translation. Here we show that non-viral transfection of episomal vectors encoding Brn4/Pou3f4, Sox2, Klf4, and c-Myc sufficiently generates iNSCs. The episomal vector mediated iNSCs closely resemble brain-derived NSCs as well as iNSCs generated by retrovirus in morphology, gene expression profile, epigenetic status, self-renewal capacity and both in vitro and in vivo differentiation capacity. The novel conversion protocol defined in the current study offers a method for generating integration-free iNSCs for the clinical research
Project description:The spinal cord does not spontaneously regenerate after injury and a treatment that ensures functional recovery after spinal cord injury (SCI) is still not available. Recently, fibroblasts have been directly converted into induced neural stem cells (iNSCs) following the forced expression of different combinations of transcription factors. Although directly converted iNSCs have been considered as a potentialcell source for clinical applications, their therapeutic potential has not been investigated yet. Here we show that iNSCs directly converted from mouse fibroblasts enhance the functional recovery after SCI in rats. Mouse embryonic fibroblasts (MEFs) were directly converted into iNSCs using four transcription factors (Brn4, Sox2, Klf4 and c-Myc). iNSCs showed gene expression profiles similar to cNSCs as determined by microarray analysis.
Project description:The spinal cord does not spontaneously regenerate after injury and a treatment that ensures functional recovery after spinal cord injury (SCI) is still not available. Recently, fibroblasts have been directly converted into induced neural stem cells (iNSCs) following the forced expression of different combinations of transcription factors. Although directly converted iNSCs have been considered as a potentialcell source for clinical applications, their therapeutic potential has not been investigated yet. Here we show that iNSCs directly converted from mouse fibroblasts enhance the functional recovery after SCI in rats. Mouse embryonic fibroblasts (MEFs) were directly converted into iNSCs using four transcription factors (Brn4, Sox2, Klf4 and c-Myc). iNSCs showed gene expression profiles similar to cNSCs as determined by microarray analysis. MEFs were derived from C3H mouse strain embryos at embryonic day (E)13.5 after removing the head and all internal organs including the gonads and the spinal cord. 5x10^4 fibroblasts were transduced with replication-defective retroviral particles coding for Sox2, Klf4, c-Myc, and Brn4. After 48 h, the transduced fibroblasts were cultured in standard NSC medium. iNSC clusters were observed 4-5 weeks after transduction and expanded. Both MEFs and cNSCs were used as negative and positive control, respectively.
Project description:Reprogramming technology enables the production of large quantities of neural progenitor cells (NPCs) from somatic cells by direct transdifferentiation. However, little is known on how neural programs in these neural stem cells (iNSCs) differ from those of alternative stem cell populations in vitro and in vivo. Here, we performed transcriptome analyses on iNSCs in comparison to brain-derived neural stem cells (NSCs) and pluripotent stem cell-derived NPCs, which revealed distinct global, neural, metabolic and cell cycle-associated marks in these populations. iNSCs carried a hindbrain/spinal cord identity, which could be shifted towards caudal, partially to rostral but not towards ventral fates in vitro. iNSCs survived after transplantation into the rodent brain and exhibited in vivo-characteristics, neural and metabolic programs similar to those of transplanted NSCs. However, iNSCs vastly retained caudal identities demonstrating cell-autonomy of regional programs in vivo. These data could have significant implications for a variety of biomedical applications using iNSCs. For microarray analysis, total RNA was isolated using the RNeasy kit (QIAGEN) according to the manufacturer´s instructions and including an on-column DNA digestion. 300 µg of RNA were subsequently used in the linear amplification protocol (Ambion) including the synthesis of T7-linked double-stranded cDNA and 12 hr of in vitro transcription incorporating biotin-labeled nucleotides. cDNA samples were hybridized as biological replicates onto MouseRef-8 v2 expression BeadChips (Illumina) for 18 hr according to the manufacturer´s instructions. Chips were washed and subsequently stained with streptavidin-Cy3 (GE Healthcare), before being scanned using the iScan reader (Illumina) and the associated software. BeadStudio 3.2 software (Illumina) was used to map bead intensities to gene information. For background correction, the Affymetrix robust multi-array analysis (RMA) background correction model was applied. Variance stabilization was performed using the log2 scaling and gene expression was normalized with the method utilized in the lumi package of R-Bioconductor.
Project description:Investigation of whole genome gene expression level changes in neural progenitor cells derived from iPS cells generated from umbilical cord mesenchymal cells, compared to neural progenitor cells derived from iPS cells generated fromskin fibroblasts. Analyze the difference between neural progenitor cells derived from iPS cells generated from different origins. The method to induce reprogramming of somatic cells and human iPS cells for neural differentiation is described in Cai J, Li W, Su H, Qin D, Yang J, et al. (2010) Generation of human induced pluripotent stem cells from umbilical cord matrix and amniotic membrane mesenchymal cells. J Biol Chem 285: 11227-11234. and Kim DS, Lee JS, Leem JW, Huh YJ, Kim JY, et al. (2010) Robust enhancement of neural differentiation from human ES and iPS cells regardless of their innate difference in differentiation propensity. Stem Cell Rev 6: 270-281. A two-chip study using total RNA recovered from one neural progenitor cell line derived from iPS cells generated from skin fibroblasts (GZF1C7NSCP3) and one neural progenitor cell line derived from iPS cells generated from umbilical cord mesenchymal cells (VMC2C7NSCP3). No replicates were made. Each chip measures the expression level of 45,033 genes from the two samples with fourteen 60-mer probe pairs (PM/MM) per gene, with three-fold technical redundancy.
Project description:Brief expression of pluripotency-associated factors such as Oct4, Klf4, Sox2 and c-Myc (OKSM), in combination with differentiation-inducing signals, has been reported to trigger transdifferentiation of fibroblasts into other cell types. Here we show that OKSM expression in mouse fibroblasts gives rise to both induced pluripotent stem cells (iPSCs) and induced neural stem cells (iNSCs) under conditions previously shown to induce only iNSCs. Fibroblast-derived iNSC colonies silenced retroviral transgenes and reactivated silenced X chromosomes, both hallmarks of pluripotent stem cells. Moreover, lineage tracing with an Oct4-CreER labeling system demonstrated that virtually all iNSC colonies originated from cells transiently expressing Oct4, whereas ablation of Oct4+ cells prevented iNSC formation. Lastly, an alternative transdifferentiation cocktail that lacks Oct4 and was reportedly unable to support induced pluripotency yielded iPSCs and iNSCs carrying the Oct4-CreER-derived lineage label. Together, these data suggest that iNSC generation from fibroblasts using OKSM and other pluripotency-related reprogramming factors requires passage through a transient iPSC state.
Project description:The overexpression of transcription factors Oct4, Sox2, Klf4, and c-Myc reprograms a somatic nucleus to one that is transcriptionally and epigenetically indistinguishable from an embryonic stem (ES) cell. However, it is still unclear if transcription factors can completely convert the nucleus of a differentiated cell into that of a distantly related cell type such that it maintains complete transcriptional and epigenetic reprogramming in the absence of exogenous factor expression. To test this idea, we screened a library of doxycycline-inducible vectors encoding neural stem cell (NSC)-expressed genes and found that stable, self-maintaining NSC-like cells could be induced under defined growth conditions after transduction of transcription factors. These induced NSCs (iNSCs) were characterized in the absence of exogenous factor induction and were shown to be transcriptionally, epigenetically, and functionally similar to endogenous embryonic cortical NSCs. Importantly, iNSCs could be generated from multiple adult cell types including liver cells and B-cells with genetic rearrangements. Our results show that self-maintaining proliferative neural cells can be induced from non-ectodermal cells by expressing specific combinations of transcription factors. Expression analysis was performed on mouse embryonic fibroblasts (MEFs), primary-derived neural stem cells (NSCs) and induced neural stem cells (iNSCs).
Project description:Brief expression of pluripotency-associated factors such as OCT4, KLF4, SOX2 and c-MYC (OKSM), in combination with differentiation-inducing signals, was reported to trigger transdifferentiation of fibroblasts into alternative cell types. Here, we show that OKSM expression gives rise to both induced pluripotent stem cells (iPSCs) and iNSCs under conditions that were previously shown to induce only NSC transdifferentiation. Fibroblast-derived iNSC colonies silenced retroviral transgenes and reactivated silenced X chromosomes, both hallmarks of pluripotent stem cells. Moreover, lineage tracing via an Oct4-CreER labeling system demonstrated that virtually all iNSC colonies originate from cells transiently expressing Oct4, whereas ablation of Oct4-positive cells prevented iNSC formation. Lastly, use of an alternative transdifferentiation cocktail that lacks OCT4 and was reportedly unable to support induced pluripotency, yielded iPSCs and iNSCs carrying the Oct4-CreER-derived lineage label. Together, these data suggest that iNSC generation using OKSM and related reprogramming factors requires passage through a transient iPSC state. 5 samples were anlyzed in total, 2 induced pluripotent stem cells (iPSCs), 1 neural stem cells (NSCs) and 2 induced NSCs (iNSCs)
Project description:Introduction: Human-derived induced pluripotent stem cell (iPSC) models of brain promise to advance our understanding of neurotoxic consequences of drug use. However, how well these models recapitulate the actual genomic landscape and cell function, as well as the drug-induced alterations, remains to be established. New in vitro models of drug exposure are needed to advance our understanding of how to protect or reverse molecular changes related to substance use disorders. Methods: We engineered a novel induced pluripotent stem cell-derived model of neural progenitor cells and neurons from cultured postmortem human skin fibroblasts, and directly compared these to isogenic brain tissue from the donor source. We assessed the maturity of the cell models across differentiation from stem cells to neurons using RNA cell type and maturity deconvolution analyses as well as DNA methylation epigenetic clocks trained on adult and fetal human tissue. As proof-of-concept of this model’s utility for substance use disorder studies, we compared morphine- and cocaine-treated neurons to gene expression signatures in postmortem Opioid Use Disorder (OUD) and Cocaine Use Disorder (CUD) brains, respectively. Results: Within each human subject (N = 2, 2 clones each), brain frontal cortex epigenetic age parallels that of skin fibroblasts and closely approximates the donor’s chronological age; stem cell induction from fibroblast cells effectively sets the epigenetic clock to an embryonic age; and differentiation of stem cells to neural progenitor cells and then to neurons progressively matures the cells via DNA methylation and RNA gene expression readouts. In neurons derived from an individual who died of opioid overdose, morphine treatment induced alterations in gene expression similar to those previously observed in OUD ex-vivo brain tissue, including differential expression of the immediate early gene EGR1, which is known to be dysregulated by opioid use. Discussion: In summary, we introduce an iPSC model generated from human postmortem fibroblasts that can be directly compared to corresponding isogenic brain tissue and can be used to model perturbagen exposure such as that seen in opioid use disorder. Future studies with this and other postmortem-derived brain cellular models, including cerebral organoids, can be an invaluable tool for understanding mechanisms of drug-induced brain alterations.