Project description:Induced pluripotent stem (iPS) cells have been derived from various somatic cell populations through ectopic expression of defined factors. It remains unclear whether iPS cells generated from different cell types are molecularly and functionally similar. Here, we show that iPS cells obtained from fibroblasts, hematopoietic and myogenic cells exhibit distinct transcriptional and epigenetic patterns. Moreover, we demonstrate that cellular origin influences the in vitro differentiation potentials of iPS cells into embryoid bodies and different hematopoietic cells. Our results suggest that low-passage iPS cells retain a transient epigenetic memory of their somatic cells of origin, which manifests as differential gene expression and altered differentiation capacity. These observations might affect ongoing attempts to use iPS cells for disease modeling and also could be exploited for potential therapeutic applications to enhance differentiation into desired cell lineages. This series consists of triplicated mRNA expression microarray data (Affymetrix mouse gene ST 1.0) for an early passage (passage 4) of mouse iPS cells derived from bone marrow granulocytes, splenic B cells, tail tip fibroblasts, and skeletel muscle precursor cells.
Project description:Induced pluripotent stem (iPS) cells have been derived from various somatic cell populations through ectopic expression of defined factors. It remains unclear whether iPS cells generated from different cell types are molecularly and functionally similar. Here, we show that iPS cells obtained from fibroblasts, hematopoietic and myogenic cells exhibit distinct transcriptional and epigenetic patterns. Moreover, we demonstrate that cellular origin influences the in vitro differentiation potentials of iPS cells into embryoid bodies and different hematopoietic cells. Our results suggest that low-passage iPS cells retain a transient epigenetic memory of their somatic cells of origin, which manifests as differential gene expression and altered differentiation capacity. These observations might affect ongoing attempts to use iPS cells for disease modeling and also could be exploited for potential therapeutic applications to enhance differentiation into desired cell lineages. This series consists of triplicated mRNA expression microarray data (Affymetrix mouse gene ST 1.0) for an early passage (passage 4) of mouse iPS cells derived from bone marrow granulocytes, splenic B cells, tail tip fibroblasts, and skeletel muscle precursor cells. iPS cells were generated by infecting somatic mouse cells with lentiviruses expressing Oct4, Sox2, Klf4, and cMyc. Total RNA was isolated from iPS cells at different passages.
Project description:The ability to induce pluripotent stem cells from committed, somatic human cells provides tremendous potential for regenerative medicine. However, there is a defined neoplastic potential inherent to such reprogramming that must be understood and may provide a model for understanding key events in tumorigenesis. Using genome-wide assays, we identify cancer-related epigenetic abnormalities that arise early during reprogramming and persist in induced pluripotent stem cell (iPS) clones. These include hundreds of abnormal gene silencing events, patterns of aberrant responses to epigenetic-modifying drugs resembling those for cancer cells, and presence in iPS and partially reprogrammed cells of cancer-specific gene promoter DNA methylation alterations. Our findings suggest that by studying the process of induced reprogramming, we may gain significant insight into the origins of epigenetic gene silencing associated with human tumorigenesis, and add to means of assessing iPS for safety. Direct expression comparison of iPS lines, cultured stem cell lines and normal differentiated cells. Re-expression experiments with 5-aza-2′-deoxycytidine (AZA) and trichostatin A (TSA) to identify hypermethylated genes.
Project description:Induced pluripotent stem (iPS) cells can be generated from somatic cells by transduction with several transcription factors in both mouse and human. However, direct reprogramming in other species has not been reported. Here, we established an efficient method to generate monkey iPS cells from fibroblasts by retrovirus-mediated introduction of the four monkey transcription factors OCT4 (POU5F1), SOX2, KLF4, and c-MYC. The monkey iPS cells displayed ES-like morphology, expressed ES cell-marker genes, shared similar global gene profiles and methylation status in the OCT4 promoter to those of monkey ES cells, and possessed the ability to differentiate into three germ layers in vitro and in vivo. Our results suggest that the mechanism of direct reprogramming is conserved among species. The efficient generation of monkey iPS cells will allow investigation of the feasibility of therapeutic cloning in primate model with various diseases. Keywords: Induced pluripotent stem, iPS, Rhesus monkey We analysed each sample (Rhesus monkey fibroblast, embryonic stem cell (ES) and induced pluripotent stem cell (iPS)) for three replications and sought to see high similarty between iPS and ES.
Project description:The generation of induced pluripotent stem (iPS) cells holds great promise in regenerative medicine. However, the relative flaws in the understanding of the molecular mechanisms promoting or limiting reprogramming still hinder the efficient generation of high quality iPS cells. Whereas modulation of the initial Oct4, Sox2, Klf4 and c-Myc (OSKM) cocktail with new transcription factors has been extensively documented, comparatively little is known about soluble molecules promoting the process, even if such recombinant factors could be highly valuable for therapeutic applications. In this study we developed a large-scale identification method to uncover novel programmed cell death (PCD)-related mechanisms limiting somatic cell reprogramming to pluripotency (SCRP). We identified Netrin-1 and its dependence receptor Dcc (Deleted in Colorectal Carcinoma), previously described for their respective survival/death functions both in normal and oncogenic contexts, as novel key SCRP modulators. We show that the early phase of SCRP is accompanied with a strong Netrin-1 deficiency, due to the improper epigenetic regulation of the Ntn1 promoter by OSKM. Mechanistically, we demonstrate that such Netrin-1 imbalance induces apoptosis mediated by the dependence receptor Dcc in a p53-independent manner. Correction of the Netrin-1/Dcc equilibrium by gain-of-ligand and loss-of-receptor experiments constrains apoptosis and improves reprogramming. As a consequence, we propose a novel iPS derivation protocol including a sequential treatment with recombinant Netrin1 that greatly facilitates the generation of mouse and human iPS cells. RNA-sequencing of mouse embryonic fibroblasts (passage 2 and passage 4), mouse pre-iPS cells (passage 5 and passage 25), 1 clone of control iPS (passage 5 and passage 25) and 2 independent clones of "Netrin-1 derived" iPS cells (passage 5 and passage 25). For this analysis, mouse iPS cell lines were grown in KSR+LIF media.
Project description:The ability to induce pluripotent stem cells from committed, somatic human cells provides tremendous potential for regenerative medicine. However, there is a defined neoplastic potential inherent to such reprogramming that must be understood and may provide a model for understanding key events in tumorigenesis. Using genome-wide assays, we identify cancer-related epigenetic abnormalities that arise early during reprogramming and persist in induced pluripotent stem cell (iPS) clones. These include hundreds of abnormal gene silencing events, patterns of aberrant responses to epigenetic-modifying drugs resembling those for cancer cells, and presence in iPS and partially reprogrammed cells of cancer-specific gene promoter DNA methylation alterations. Our findings suggest that by studying the process of induced reprogramming, we may gain significant insight into the origins of epigenetic gene silencing associated with human tumorigenesis, and add to means of assessing iPS for safety.
Project description:he ability to induce pluripotent stem cells from committed, somatic human cells provides tremendous potential for regenerative medicine. However, there is a defined neoplastic potential inherent to such reprogramming that must be understood and may provide a model for understanding key events in tumorigenesis. Using genome-wide assays, we identify cancer-related epigenetic abnormalities that arise early during reprogramming and persist in induced pluripotent stem cell (iPS) clones. These include hundreds of abnormal gene silencing events, patterns of aberrant responses to epigenetic-modifying drugs resembling those for cancer cells, and presence in iPS and partially reprogrammed cells of cancer-specific gene promoter DNA methylation alterations. Our findings suggest that by studying the process of induced reprogramming, we may gain significant insight into the origins of epigenetic gene silencing associated with human tumorigenesis, and add to means of assessing iPS for safety.
Project description:he ability to induce pluripotent stem cells from committed, somatic human cells provides tremendous potential for regenerative medicine. However, there is a defined neoplastic potential inherent to such reprogramming that must be understood and may provide a model for understanding key events in tumorigenesis. Using genome-wide assays, we identify cancer-related epigenetic abnormalities that arise early during reprogramming and persist in induced pluripotent stem cell (iPS) clones. These include hundreds of abnormal gene silencing events, patterns of aberrant responses to epigenetic-modifying drugs resembling those for cancer cells, and presence in iPS and partially reprogrammed cells of cancer-specific gene promoter DNA methylation alterations. Our findings suggest that by studying the process of induced reprogramming, we may gain significant insight into the origins of epigenetic gene silencing associated with human tumorigenesis, and add to means of assessing iPS for safety. Methylation was analyzed using Illumina's 27k Infinium platform for direct detection of methylation after bisulfite conversion. The overall methylation status was determined for several iPS lines and the pool cells from which they are derived. These methylation levels can be compared directly to those of cultured stem cells, differentiated cells and cancer cell lines.
Project description:In pluripotential reprogramming, a pluripotent state is established within somatic cells. In this study, we have generated induced pluripotent stem (iPS) cells from bi-maternal (uniparental) parthenogenetic neural stem cells (pNSCs) by transduction with four (Oct4, Klf4, Sox2, and c-Myc) or two (Oct4 and Klf4) transcription factors. The parthenogenetic iPS (piPS) cells directly reprogrammed from pNSCs were able to generate germline-competent himeras, and hierarchical clustering analysis showed that piPS cells were clustered more closer to parthenogenetic ES cells than normal female ES cells. Interestingly, piPS cells showed loss of parthenogenetic-specific imprinting patterns of donor cells. Microarray data also showed that the maternally imprinted genes, which were not expressed in pNSCs, were upregulated in piPS cells, indicating that pluripotential reprogramming lead to induce loss of imprinting as well as re-establishment of various features of pluripotent cells in parthenogenetic somatic cells. 5 samples were analyzed by microarray, each one them in duplicate. fNSC: Mouse female NSC (Neural Stem Cell) pNSC: Mouse parthenogenetic NSC (Neural Stem Cell) piPS-2F: Mouse parthenogenetic induced pluripotent cells derived from NSC overexpressing Oct4 and Klf4 pESC-B: Mouse parthenogenetic ESC (Embryonic Stem Cell) SSEA-1 sorted fESC: Mouse female ESC (Embryonic Stem Cell) OG2
Project description:In comprehensive glycome analysis with a high-density lectin microarray, we have previously shown that the recombinant N-terminal domain of the lectin BC2L-C from Burkholderia cenocepacia (rBC2LCN) binds exclusively to undifferentiated human induced pluripotent stem (iPS) cells and embryonic stem (ES) cells but not to differentiated somatic cells. Here we demonstrate that podocalyxin, a heavily glycosylated type1 transmembrane protein, is the predominant glycoprotein ligand of rBC2LCN on human iPS cells and ES cells. When analyzed by DNA microarray, podocalyxin was found to be highly expressed in both iPS cells and ES cells. Western and lectin blotting revealed that rBC2LCN binds predominantly to podocalyxin with a high molecular weight of more than 240 kDa in undifferentiated iPS cells of six different origins and four ES cell lines, but no binding was observed in either differentiated mouse feeder cells or somatic cells. The specific binding of rBC2LCN to podocalyxin prepared from a large set of iPS cells (138 types) and ES cells (15 types) was also confirmed using a high-throughput antibody-overlay lectin microarray. Alkaline digestion greatly reduced the binding of rBC2LCN to podocalyxin, indicating that the major glycan ligands of rBC2LCN are presented on O-glycans. Furthermore, rBC2LCN was found to exhibit significant affinity to a branched Oglycan comprising an H type3 structure as the most probable rBC2LCN glycan ligand (Kd, 4.0 x 10-5 M) prepared from human 201B7 iPS cells, suggesting that H type3 is a novel potential pluripotency marker. We conclude that podocalyxin is the predominant glycoprotein ligand of rBC2LCN on human iPS cells and ES cells. Gene expressions in human embryonic stem cells (ESCs) and human induced pluripotent stem cells (iPSCs). Human iPS cells (MRC5-iPS, AM-iPS, UtE-iPS, PAE-iPS) were induced from four different somatic cells by infection of the retroviral vectors pMXs encoding OCT3/4, SOX2, KLF4 and c-MYC, simultaneously. Human iPS cells (TIG/MKOS#19, #56, #106) were generated through reprogramming by Sendai virus infection-mediated expression of OCT4, SOX2, KLF4, and c-MYC.