Reprogramming of mouse somatic cells into pluripotent stem cells using a combination of small molecules
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ABSTRACT: Somatic cells can be reprogrammed to generate induced pluripotent stem cells (iPSCs) by overexpression of four transcription factors, Oct4, Klf4, Sox2, and c-Myc. Bmi1 is responsible for conversion of adult mouse astrocytes and fibroblasts into neural stem cell-like cells and conversion of fibroblasts into iPSCs under enforced expression of Oct4. Here, in the first step of generating iPSCs, stable intermediate cells were generated from mouse astrocytes by Bmi1 in the absence of other transcription factors. These cells [called induced epiblast stem cell (EpiSC)-like cells (iEpiSCLCs)] are similar to EpiSCs in terms of expression of specific markers, epigenetic state, and ability to differentiate into three germ layers. Treatment with MEK/ERK and GSK3 pathway inhibitors in the presence of leukemia inhibitory factor resulted in conversion of iEpiSCLCs into iPSCs that were similar to mouse embryonic stem cells (mESCs), suggesting that Bmi1 is sufficient to reprogram astrocytes to pluripotency. Next, Bmi1 function was replaced with Shh activators (oxysterol and purmorphamine), which demonstrated that specific combinations of small molecules alone can reprogram mouse fibroblasts into iPSCs. These iPSCs resembled mESCs in terms of global gene expression profile, epigenetic status, and developmental potential, demonstrating that combinations of small molecules can compensate for reprogramming factors and are sufficient to directly reprogram mouse somatic cells into iPSCs. 4 Affymetrix and 4 Agilent samples
Project description:Somatic cells can be reprogrammed to generate induced pluripotent stem cells (iPSCs) by overexpression of four transcription factors, Oct4, Klf4, Sox2, and c-Myc. Bmi1 is responsible for conversion of adult mouse astrocytes and fibroblasts into neural stem cell-like cells and conversion of fibroblasts into iPSCs under enforced expression of Oct4. Here, in the first step of generating iPSCs, stable intermediate cells were generated from mouse astrocytes by Bmi1 in the absence of other transcription factors. These cells [called induced epiblast stem cell (EpiSC)-like cells (iEpiSCLCs)] are similar to EpiSCs in terms of expression of specific markers, epigenetic state, and ability to differentiate into three germ layers. Treatment with MEK/ERK and GSK3 pathway inhibitors in the presence of leukemia inhibitory factor resulted in conversion of iEpiSCLCs into iPSCs that were similar to mouse embryonic stem cells (mESCs), suggesting that Bmi1 is sufficient to reprogram astrocytes to pluripotency. Next, Bmi1 function was replaced with Shh activators (oxysterol and purmorphamine), which demonstrated that specific combinations of small molecules alone can reprogram mouse fibroblasts into iPSCs. These iPSCs resembled mESCs in terms of global gene expression profile, epigenetic status, and developmental potential, demonstrating that combinations of small molecules can compensate for reprogramming factors and are sufficient to directly reprogram mouse somatic cells into iPSCs.
Project description:Somatic cells can be reprogrammed into induced pluripotent stem (iPS) cells by Oct4, Sox2, Klf4, plus c-Myc. Recently, Sox2 plus Oct4 were shown to reprogram fibroblasts and Oct4 alone to reprogram mouse and human neural stem cells (NSCs) into iPS cells. Here we report that Bmi1 leads to dedifferentiation of mouse fibroblasts into NSC-like cells and, in combination with Oct4, replaces Sox2, Klf4 and c-Myc during reprogramming fibroblasts to iPS cells. Furthermore, activation of sonic hedgehog signalling (by Shh, purmorphamine, or oxysterol) replaces the effects of Bmi1, and, in combination with Oct4, reprograms mouse embryonic and adult fibroblasts into iPS cells. One-and two-factor iPS cells are similar to mouse embryonic and adult fibroblasts into iPS cells in global gene expression profile, epigenetic status, in vitro and in bibo differentiation into all three ferm layers, as well as teratoma formation and germline transmission in vivo. These data support that fibroblasts can be reprogrammed into iPS cells by Oct4 alone. Total RNAs were isolated from indicated cells and labeled with Cy3. Hybridization was performed once for each sample.
Project description:Somatic cells can be reprogrammed into induced pluripotent stem (iPS) cells by Oct4, Sox2, Klf4, plus c-Myc. Recently, Sox2 plus Oct4 were shown to reprogram fibroblasts and Oct4 alone to reprogram mouse and human neural stem cells (NSCs) into iPS cells. Here we report that Bmi1 leads to dedifferentiation of mouse fibroblasts into NSC-like cells and, in combination with Oct4, replaces Sox2, Klf4 and c-Myc during reprogramming fibroblasts to iPS cells. Furthermore, activation of sonic hedgehog signalling (by Shh, purmorphamine, or oxysterol) replaces the effects of Bmi1, and, in combination with Oct4, reprograms mouse embryonic and adult fibroblasts into iPS cells. One-and two-factor iPS cells are similar to mouse embryonic and adult fibroblasts into iPS cells in global gene expression profile, epigenetic status, in vitro and in bibo differentiation into all three ferm layers, as well as teratoma formation and germline transmission in vivo. These data support that fibroblasts can be reprogrammed into iPS cells by Oct4 alone.
Project description:Hypoxia enhances the reprogramming efficiency of human dermal fibroblasts to become induced pluripotent stem cells (iPSCs). Because we showed previously that the hypoxia facilitates the isolation and maintenance of human dental pulp cells (DPCs), we examined here whether it promotes the reprogramming of DPCs to become iPSCs. To investigate the effect of oxygen concentration on global gene expression, we compared DPCs cultured for 6 days under hypoxia and normoxia.
Project description:The inclusion of oocyte factors together with Yamanaka’s previously identified reprogramming factors (OCT4, SOX2, KLF4 with or without cMYC; OSK(M)) may facilitate the reprogramming process that leads to induced pluripotent stem cells (iPSCs). We previously applied label-free LC-MS/MS analysis to search for such facilitators of reprogramming (reprogrammome), resulting in a catalog of 28 candidates that are (i) able to robustly access the cell nucleus, and (ii) shared between mature mouse oocytes and pluripotent embryonic stem (ES) cells. In the present study we hypothesized that our 28 reprogrammome candidates would also be (iii) abundant in mature mouse oocytes, (iv) depleted after oocyte-to-embryo transition, and (v) able to potentiate or replace the OSKM factors during iPSC reprogramming. Using LC-MS/MS and isotopic labeling methods we found that the abundance profiles of the 28 proteins was below that of known oocyte-specific and housekeeping proteins. Out of the 28 proteins only arginine methyltransferase 7 (PRMT7) presented a substantially changing profile during mouse embryogenesis and impacted on the conversion of mouse fibroblasts into iPSCs. PRMT7 indeed could very efficiently replace SOX2 in a factor-substitution assay yielding iPSCs. These findings show that proteomics can be used to prioritize the functional analysis of reprogrammome candidates.
Project description:The pupose of this study is to explore tanalysis to investigate the different phenotypes between homozygous and compound heterozygous genotypes in different brain cell types, including patient-specific fibroblasts, iPSCs and iPSCs-derived neural stem cells (NSCs), and astrocytes.
Project description:Leptin receptors (Lepr) are expressed by various types of stem cells including mesenchymal stem cells, hematopoietic stem cells, embryonic stem cells, and induced pluripotent stem cells. Leptin/lepr signaling is also a central regulator of metabolism. However, the role of Lepr in pluripotency, metabolic disease progression and growth development is still controversial and poorly understood. In the present study, we explored the Lepr function in disease progression, pluripotency and metabolism using day 14.5 mouse embryonic fibroblasts (MEFs) and their reprogrammed induced pluripotent stem cells (iPSCs) as model system. We successfully reprogrammed mouse embryonic fibroblasts into iPSCs from control and db/db (Lepr deficient) mice. Using a global quantitative proteomic approach, we identified key pathways regulating pluripotency, metabolic homeostasis and protein synthesis during fetal growth and development. The Lepr MEFs show abnormal metabolic abnormalities and mitochondrial dysfunction as compared to control MEFs, while Lepr iPSCs show upregulated elongated factor 4 e (eIF4e) protein synthesis pathway and altered Oct4 and Stat3 pathways which are involved in normal fetal growth development. Furthermore, chip analysis revealed that higher Stat3 binding on the promoter of eIF4e in Lepr iPSCs leads to higher protein synthesis in these cell types as compared to control iPSCs. Finally, point mutation corrected Lepr iPSCs using CRISPR/Cas9 gene editing method showed recovered pluripotency, metabolic and protein synthesis pathways. In conclusion, we have shown that Lepr signaling is involved in the regulation of the metabolic properties and key developmental pathways in MEFs and stemness of pluripotent stem cells. Disruption of Lepr signaling has been shown to involve in the pathophysiology of various diseases including obesity and diabetes. The generated MEFs and iPSCs in this present study provide valuable tools to explore the role of Lepr in the progression of obesity, diabetes and metabolic abnormalities, and to find the putative targets of Lepr signaling during the development of these diseases.
Project description:Partial induced pluripotent cells (iPSCs) are cell lines strayed from normal route from somatic cells to iPSCs and are immortalized. Mouse partial iPSCs are able to convert to real iPSCs by the exposure to 2i condition using MAPK and GSK3? inhibitors. However, the molecular mechanisms of this conversion are totally not known. Our piggyback vector mediated genome-wide screen revealed that Cnot2, one of core components of Ccr4-Not complex participates in this conversion. Subsequent analyses revealed other core components, i.e., Cnot1 and Cnot3 and Trim28 which is known to extensively share genomic binding sites with Cnot3 contribute to this conversion as well. Our bioinformatics analyses indicate that the major role of these factors in the conversion is the down-regulation of developmental genes in partial iPSCs. Two partial iPSC clones (2B1 and 5C5) cultured under conventional culture condition with leukemia inhibitory factor (LIF) and serum and those converted to iPSCs by the exposure to 2i condition were used for RNA source. Partial iPSCs (2B1) cultured under conventional condition in which either one of Cnot1, Cnot2, Cnot3 and Trim28 cDNA or these factors were combinatorially incorporated after retrovirus infection and those in which empty vector or Nanog were stably integrated were also used for RNA source. In addition, embryonic fibroblasts and embryonic stem cells (ESCs) from 13.5 dpc embryos and blastocysts, respectively, from Nanog-GFP transgenic mice and wild-type ESC line (EBRTcH3) were used for RNA source.
Project description:Mutations in presenilin 1 (PSEN1) cause a familiar form of Alzheimer's disease (AD). We have obtained skin biopsies from two individuals carrying PSEN1 exon9 deletion and reprogrammed skin fibroblasts into induced pluripotent stem cells (iPSCs). To get controls, we have corrected PSEN1 exon9 deletion by CRISPR/Cas9 technique. Since astrocytes play role in AD pathogenesis, we further differentiated iPSCs into astrocytes. We ran RNA sequencing analysis to compare our iPSC-derived astrocytes with previously published data on human astrocytes and to identify genes and pathways affected by PSEN1 exon 9 deletion.