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- 저자 : Scholer, Hans R. (검색결과 6 건)
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The Role of Pou5f1 Gene on Primed Pluripotency and Differentiation into Germ Layers
Hyun Woo Choi,Hans R. Scholer 한국동물생명공학회(구 한국동물번식학회) 2017 발생공학 국제심포지엄 및 학술대회 Vol.2017 No.10
Pluripotent stem cells (PSCs) can be differentiated into all three germ layers in vitro. The pluripotent stem cells are derived from the inner cell mass of blastocyst in vitro, termed embryonic stem cells (ESCs). The epiblast derived pluripotent stem cells (Epi- SCs) represent a more differentiated state than plurioptent ESCs. The pluripotent ESCs and EpiSCs express Oct4 (Pou5f1) gene. Oct4 gene is essential for maintenance of pluripotent ESCs. The pluriopotent ESCs are induced differentiation into trophectoderm by decreasing Oct4 levels below 50%. Oct4 levels regulate cell fate of pluripotent stem cells. Here, we established ZHBTc4-ESCs derived epiblast stem cells like cells (ZHBTc4- EpiLCs). ZHBTc4-EpiLCs could not be maintained in doxycycline (dox) contained EpiSC medium, indicated that Oct4 gene is essential for maintenance of primed EpiLCs. We also tried to differentiate ZHBTc4-EpiLCs into neuroectoderm or mesoendoderm lineages with or without dox. The ZHBTc4-EpiLCs could be efficiently differentiated into neuroectoderm lineage with dox, whereas these cells could not be differentiated into mesoendoderm lineage with dox. This results showed that Oct4 gen
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Homogeneity of XEN Cells Is Critical for Generation of Chemically Induced Pluripotent Stem Cells
고기남,정다희,Yukyeong Lee,이승원,함석범,Minseong Lee,Na Young Choi,Guangming Wu,Hans R. Scholer 한국분자세포생물학회 2023 Molecules and cells Vol.46 No.4
In induced pluripotent stem cells (iPSCs), pluripotency is induced artificially by introducing the transcription factors Oct4, Sox2, Klf4, and c-Myc. When a transgene is introduced using a viral vector, the transgene may be integrated into the host genome and cause a mutation and cancer. No integration occurs when an episomal vector is used, but this method has a limitation in that remnants of the virus or vector remain in the cell, which limits the use of such iPSCs in therapeutic applications. Chemical reprogramming, which relies on treatment with small-molecule compounds to induce pluripotency, can overcome this problem. In this method, reprogramming is induced according to the gene expression pattern of extra-embryonic endoderm (XEN) cells, which are used as an intermediate stage in pluripotency induction. Therefore, iPSCs can be induced only from established XEN cells. We induced XEN cells using small molecules that modulate a signaling pathway and affect epigenetic modifications, and devised a culture method which can produce homogeneous XEN cells. At least 4 passages were required to establish morphologically homogeneous chemically induced XEN (CiXEN) cells, whose properties were similar to those of XEN cells, as revealed through cellular and molecular characterization. Chemically iPSCs derived from CiXEN cells showed characteristics similar to those of mouse embryonic stem cells. Our results show that the homogeneity of CiXEN cells is critical for the efficient induction of pluripotency by chemicals.
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A Novel Feeder-Free Culture System for Expansion of Mouse Spermatogonial Stem Cells
Choi, Na Young,Park, Yo Seph,Ryu, Jae-Sung,Lee, Hye Jeong,Arauzo-Bravo, Marcos J.,Ko, Kisung,Han, Dong Wook,Scholer, Hans R.,Ko, Kinarm Korean Society for Molecular and Cellular Biology 2014 Molecules and cells Vol.37 No.6
Spermatogonial stem cells (SSCs, also called germline stem cells) are self-renewing unipotent stem cells that produce differentiating germ cells in the testis. SSCs can be isolated from the testis and cultured in vitro for long-term periods in the presence of feeder cells (often mouse embryonic fibroblasts). However, the maintenance of SSC feeder culture systems is tedious because preparation of feeder cells is needed at each subculture. In this study, we developed a Matrigel-based feeder-free culture system for long-term propagation of SSCs. Although several in vitro SSC culture systems without feeder cells have been previously described, our Matrigel-based feeder-free culture system is time- and cost-effective, and preserves self-renewability of SSCs. In addition, the growth rate of SSCs cultured using our newly developed system is equivalent to that in feeder cultures. We confirmed that the feeder-free cultured SSCs expressed germ cell markers both at the mRNA and protein levels. Furthermore, the functionality of feeder-free cultured SSCs was confirmed by their transplantation into germ cell-depleted mice. These results suggest that our newly developed feeder-free culture system provides a simple approach to maintaining SSCs in vitro and studying the basic biology of SSCs, including determination of their fate.
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Lee, Seung-Won,Wu, Guangming,Choi, Na Young,Lee, Hye Jeong,Bang, Jin Seok,Lee, Yukyeong,Lee, Minseong,Ko, Kisung,Scholer, Hans R.,Ko, Kinarm Korean Society for Molecular and Cellular Biology 2018 Molecules and cells Vol.41 No.7
Spermatogonial stem cells (SSCs) derived from mouse testis are unipotent in regard of spermatogenesis. Our previous study demonstrated that SSCs can be fully reprogrammed into pluripotent stem cells, so called germline-derived pluripotent stem cells (gPS cells), on feeder cells (mouse embryonic fibroblasts), which supports SSC proliferation and induction of pluripotency. Because of an uncontrollable microenvironment caused by interactions with feeder cells, feeder-based SSC reprogramming is not suitable for elucidation of the self-reprogramming mechanism by which SSCs are converted into pluripotent stem cells. Recently, we have established a Matrigel-based SSC expansion culture system that allows longterm SSC proliferation without mouse embryonic fibroblast support. In this study, we developed a new feeder-free SSC self-reprogramming protocol based on the Matrigel-based culture system. The gPS cells generated using a feeder-free reprogramming system showed pluripotency at the molecular and cellular levels. The differentiation potential of gPS cells was confirmed in vitro and in vivo. Our study shows for the first time that the induction of SSC pluripotency can be achieved without feeder cells. The newly developed feeder-free self-reprogramming system could be a useful tool to reveal the mechanism by which unipotent cells are self-reprogrammed into pluripotent stem cells.
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Direct Reprogramming of Fibroblasts into Neural Stem Cells by Defined Factors
Han, D.,Tapia, N.,Hermann, A.,Hemmer, K.,Hoing, S.,Arauzo-Bravo, Marcos J.,Zaehres, H.,Wu, G.,Frank, S.,Moritz, S.,Greber, B.,Yang, J.,Lee, H.,Schwamborn, Jens C.,Storch, A.,Scholer, Hans R. Cell Press 2012 Cell stem cell Vol.10 No.4
Recent studies have shown that defined sets of transcription factors can directly reprogram differentiated somatic cells to a different differentiated cell type without passing through a pluripotent state, but the restricted proliferative and lineage potential of the resulting cells limits the scope of their potential applications. Here we show that a combination of transcription factors (Brn4/Pou3f4, Sox2, Klf4, c-Myc, plus E47/Tcf3) induces mouse fibroblasts to directly acquire a neural stem cell identity-which we term as induced neural stem cells (iNSCs). Direct reprogramming of fibroblasts into iNSCs is a gradual process in which the donor transcriptional program is silenced over time. iNSCs exhibit cell morphology, gene expression, epigenetic features, differentiation potential, and self-renewing capacity, as well as in vitro and in vivo functionality similar to those of wild-type NSCs. We conclude that differentiated cells can be reprogrammed directly into specific somatic stem cell types by defined sets of specific transcription factors.
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