Project description:A single spermatogonial stem cell can aquire pluripotentiality but that conversion into a pluripotent cell type is accompanied by loss of spermatogenic potential. We used microarrays to compare the expression profiles among the different stem cell types. Experiment Overall Design: GS, mGS and ES cells were cultured for RNA extraction and hybridization on Affymetrix microarrays. We examined the gene expression profiles of GS and mGS cells to find candidate molecules that are involved in the conversion process of GS into mGS cells.
Project description:Müller glial cells (MGs) play important roles in human retina during physiological and pathological conditions. However, there are still many obstacles to obtain large numbers of human MGs in vitro so far, which hinder the further study of MGs. Human induced pluripotent stem cells (hiPSCs) have capacity to differentiate into almost all body cells, even develop complex, organized tissues, including retinal organoids (ROs) with all cell subtypes, providing many opportunities in study of retinal development and disorders. This study explored the development of MGs within hiPSC-derived ROs and the approach to isolate and expand these MGs. In ROs, MG precursors expressing SOX9 and Ki67 appeared since differentiation day 60 (D60), while SOX9+ CRALBP+ GS+ and Ki67- mature MGs developed from D150. MGs isolated from ROs aged older than 120 days could be expanded and exhibited a spindle-like morphology under adherent culture conditions. These expanded cells expressed MG specific markers SOX9, vimentin, nestin, CRALBP and GS, and responded to L-glutamate stimuli revealed by whole-cell patch-clamp recordings. They could be passaged several times, yielding large numbers of cells in a short period. In addition, they did not transdifferentiate into other types of retinal cells after subretinal transplantation in NOD/SCID mice. This study firstly clarified the timecourse of human MG development in ROs, and established a simple approach to expand and enrich these cells from ROs, paving the way for downstream investigation and application of human MGs.
Project description:Spermatogonial stem cells (SSCs) have pluripotent potential. However, frequency of pluripotent cell derivation is low and the mechanism of culture-induced reprogramming remains unknown. Here we report that epigenetic instability of germline stem (GS) cells, cultured SSCs, induces pluripotent cell derivation. GS cells undergo DNA demethylation in H19 differentially methylated region under low-density culture. When H19 demethylation was induced by Dnmt1 depletion, they converted into embryonic stem (ES)-like cells. Dnmt1 depletion downregulated Dmrt1 expression, whose depletion also induced pluripotency. Functional screening of Dmrt1 target gene revealed that Dmrt1 depletion upregulates Sox2, the key molecule responsible for generating induced pluripotent stem cells. Although Sox2 transfection upregulated Oct4 and produced pluripotent cells, this conversion was inhibited by Oct1 overexpression, suggesting that the balance of Oct proteins maintains SSC identity. These results suggest that culture-induced reprogramming is caused by unstable DNA methylation, and that Dmrt1-Sox2 cascade is critical for regulating pluripotency in SSCs. Pluripotent stem-like cells were induced from GS cells by down-regulation of Dnmt/Dmrt, or up-regulation of Sox2/Oct4 in combination with p53 knock-down and their total RNA samples were subjected to microarray analysis to compare their gene expression profile with other pluripotent stem cells such as ES cells or iPS cells.
Project description:We have recently developed a new generation of induced stem cells that we have called “induced Tissue Stem cells” (iTSCs) which are generated by using low doses of non-integrative vectors encoding several embryonic reprogramming factors permitting to de-differentiate the cells without passing through a pluripotent state. ITSCs are thus multipotent stem cells rather than pluripotent stem cells. Using this technology we have produced endodermic iTSCs by de-differentiation of murine hepatocytes and shown that they are able to differentiate in vitro and in vivo into tissues restricted to endodermic layers. We report the gene expression profiles of two subclones of murine hepatocytes-reprogrammed iTSCs and of hepatocytes parental cells and murine embryonic stem cells (D3). Adherent liver cultures were established from 6 to 8 week old mice and one million of hepatocytes were infected with adenovirus encoding Oct4, Sox2, cMyc and Klf4. After 5 days of infections, cells were manually pooled and plated on mitomycin C-arrested Mouse Embryonic fibroblasts (MEF) in daily changed ES cell culture medium. In this manner, more than 50 colonies have been isolated and for two of them (clones 3 and 6), single cells were added in a 96-well cell culture plate for subcloning. Two subclones ; 6.6 and 3.8 were evaluated by microarray. The transcriptome was analyzed with Affymetrix microarray technology (GeneChip ® Mouse Gene 2.0 ST Array) and the data were normalized by the RMA method and annotated with Partek GS and R Bioconductor softwares.
Project description:Comparison of gene expression between Xist KO germ line stem GS cells and wildtype GS cells The gene expression of GS cells derived from postnatal mouse testis was investigated. RNA from Xist KO-, wildtype-GS cells, and ES cells were used for this study. 3 independent samples from each cell line were used.
Project description:Spermatogonial stem cells (SSCs) have pluripotent potential. However, frequency of pluripotent cell derivation is low and the mechanism of culture-induced reprogramming remains unknown. Here we report that epigenetic instability of germline stem (GS) cells, cultured SSCs, induces pluripotent cell derivation. GS cells undergo DNA demethylation in H19 differentially methylated region under low-density culture. When H19 demethylation was induced by Dnmt1 depletion, they converted into embryonic stem (ES)-like cells. Dnmt1 depletion downregulated Dmrt1 expression, whose depletion also induced pluripotency. Functional screening of Dmrt1 target gene revealed that Dmrt1 depletion upregulates Sox2, the key molecule responsible for generating induced pluripotent stem cells. Although Sox2 transfection upregulated Oct4 and produced pluripotent cells, this conversion was inhibited by Oct1 overexpression, suggesting that the balance of Oct proteins maintains SSC identity. These results suggest that culture-induced reprogramming is caused by unstable DNA methylation, and that Dmrt1-Sox2 cascade is critical for regulating pluripotency in SSCs.
Project description:Spermatogonial stem cells (SSCs) undergo self-renewal division to sustain spermatogenesis. Although it is possible to derive germline stem (GS) cell cultures from most of the mouse strains by supplementing GDNF and FGF2, SSCs from a 129 background do not proliferate under the same culture conditions, which suggested that they have distinct self-renewal requirements. We modified previous culture conditions and established long-term culture of SSCs of 129 mice. 129 GS cells reinitiated spermatogenesis and produced offspring following transplantation into the seminiferous tubules of infertile mouse recipients. This dataset show the differences of gene expressions of GS cells between C57BL/6 and 129 mice, which have important implications in understanding requirements of self-renewal mechanisms. In this dataset, we include the expression data obtained from cultured spermatogonia (GS cells) derived from C57BL/6, and 129 mice. Each group contains 2 biological replicates.