Basic biology of reprogramming IPSC There has been great interest in the production of pluripotent iPSCs from adults, because of their biologic interest and potential value for studying mechanisms of human disease, and potentially ultimately for regenerative medicine. However, the induction requires several weeks and is generally very inefficient, in that only a small fraction of the cells are induced. On prolonged cultivation with inducing factors, almost all cells can give rise to progeny among which are iPSCs, so that conversion appears to involve some stochastic event that can occur in many cells rather than being limited to a few pre-determined cells in any culture. However, cell populations may be heterogeneous with respect to their ease of conversion. Conversion of somatic cells to IPSCs may follow a defined sequence of events, possibly involving early repression of differentiation markers and morphologic changes reminiscent of a transition from mesenchymal to epithelial cells, followed by the expression of ES-like markers of dedifferentiation, and finally by the activation of endogenous Nanog. Also, not all emerging colonies develop into fully pluripotent cells, suggesting that the conversion process requires multiple separable steps. Even after development of iPSCs they may retain markers such as sites of DNA methlylation that retain traces of their cell of origin, and progressive passage of the cells may cause them to be progressively more like embryonic stem (ES) cells, Epigenetic reprogramming of iPS cells: When induced to pluripotency, somatic cells acquire the features of ES cell-like states in their gene expression and epigenetic status. Human ES cells have histone modification states that allow them to differentiate into all three germ layers when instructed. So-called bivalent H3K4methylation and H3K27methylation on developmentally important genes are conserved in pluripotent cells. In addition, IPSCs acquire an ES cell-like global DNA methylation pattern. However, current factor-based reprogramming does not completely reprogram somatic epigenetic state to the ES cell state, and cells retain s significant number of iPSC specific differential methylated regions (DMRs) distinct from those of human ES cells. The aberrant epigenetic reprogramming affects the differentiation potential of IPSCs. Due to the extremely low efficiency of human somatic cell reprogramming. the elucidation of epigenetic changes during reprogramming induction has been challenging. By combining the technical advancement in analyzing global gene expression. DNA methylation analysis, and histone modification with isolation of cells of intermediate stages of reprogramming. we will reveal the sequence of epigenetic changes. Considering the importance of application of iPSCs in cell therapy and novel in vitro disease modeling, dissecting the epigenetic modification of reprogramming has high impact.

Agency
National Institute of Health (NIH)
Institute
National Institute of General Medical Sciences (NIGMS)
Type
Research Program Projects (P01)
Project #
5P01GM099130-03
Application #
8550095
Study Section
Special Emphasis Panel (ZGM1-GDB-8)
Project Start
Project End
Budget Start
2013-09-01
Budget End
2014-08-31
Support Year
3
Fiscal Year
2013
Total Cost
$555,696
Indirect Cost
$6,096
Name
Stanford University
Department
Type
DUNS #
009214214
City
Stanford
State
CA
Country
United States
Zip Code
94305
Han, Lin; Zi, Xiaoyuan; Garmire, Lana X et al. (2014) Co-detection and sequencing of genes and transcripts from the same single cells facilitated by a microfluidics platform. Sci Rep 4:6485
Dan, Jiameng; Liu, Yifei; Liu, Na et al. (2014) Rif1 maintains telomere length homeostasis of ESCs by mediating heterochromatin silencing. Dev Cell 29:7-19
Benayoun, Bérénice A; Pollina, Elizabeth A; Ucar, Duygu et al. (2014) H3K4me3 breadth is linked to cell identity and transcriptional consistency. Cell 158:673-88
Tanaka, Yoshiaki; Kim, Kun-Yong; Zhong, Mei et al. (2014) Transcriptional regulation in pluripotent stem cells by methyl CpG-binding protein 2 (MeCP2). Hum Mol Genet 23:1045-55
Guo, Shangqin; Zi, Xiaoyuan; Schulz, Vincent P et al. (2014) Nonstochastic reprogramming from a privileged somatic cell state. Cell 156:649-62
Kim, Kun-Yong; Hysolli, Eriona; Tanaka, Yoshiaki et al. (2014) X Chromosome of female cells shows dynamic changes in status during human somatic cell reprogramming. Stem Cell Reports 2:896-909
Liu, Na; Liu, Lin; Pan, Xinghua (2014) Single-cell analysis of the transcriptome and its application in the characterization of stem cells and early embryos. Cell Mol Life Sci 71:2707-15
Ebert, Antje D; Kodo, Kazuki; Liang, Ping et al. (2014) Characterization of the molecular mechanisms underlying increased ischemic damage in the aldehyde dehydrogenase 2 genetic polymorphism using a human induced pluripotent stem cell model system. Sci Transl Med 6:255ra130
Buecker, Christa; Srinivasan, Rajini; Wu, Zhixiang et al. (2014) Reorganization of enhancer patterns in transition from naive to primed pluripotency. Cell Stem Cell 14:838-53
Sanchez-Freire, Veronica; Lee, Andrew S; Hu, Shijun et al. (2014) Effect of human donor cell source on differentiation and function of cardiac induced pluripotent stem cells. J Am Coll Cardiol 64:436-48

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