The Greatwall-Endosulfine switch accelerates autophagic flux during the cell divisions leading to G1 arrest and quiescence in fission yeast
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ABSTRACT:
ORGANISM(S): Schizosaccharomyces pombe
PROVIDER: GSE217398 | GEO | 2022/11/09
REPOSITORIES: GEO
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Project description:The Greatwall-Endosulfine switch accelerates autophagic flux during the cell divisions leading to G1 arrest and quiescence in fission yeast
| PRJNA898803 | ENA
Project description:Quiescence is a distinct cell cycle phase, termed G0, in which growth, transcription, translation, and replication are suppressed. Yeast cells enter G0 following glucose exhaustion but remain viable for an extended period and can re-enter the cell cycle when returned to glucose-rich medium. Quiescence is a feature of all organisms and is essential for the maintenance of stem cells and tissue renewal. Quiescence is also related to chronological lifespan (CLS) - or the capacity of post-mitotic quiescent cells to survive over time - and thus contributes to longevity. However, important questions remain to be answered regarding the mechanisms that control entry into quiescence, the maintenance of quiescence, and the re-entry of quiescent cells into the cell cycle. Histone acetylation is lost during the formation of quiescent yeast cells, and chromatin becomes highly condensed. This unique chromatin landscape plays a key role in supporting quiescence-specific transcriptional repression and has been linked to the formation and maintenance of quiescent cells. To ask if other chromatin features regulate quiescence, we conducted a comprehensive screen of histone H3 and H4 mutants. We identified several mutants that show altered quiescence entry and have characterized their chromatin phenotypes. None of these mutants retain histone acetylation, while several have altered chromatin condensation. Additionally, a screen for H3 and H4 mutants with altered chronological lifespan showed that CLS is highly correlated with quiescence entry.
2023-03-01 | GSE210305 | GEO
Project description:Yes-associated protein (YAP), a major effector of the Hippo signalling pathway, is widely implicated in vascular pathophysiology processes. Here, we identify a new role of YAP in the regulation of vascular senescence. The inhibition or deficiency and overexpression of YAP were performed in human umbilical vein endothelial cells (HUVECs) and isolated vascular tissues. Cellular and vascular senescence was assessed by analysis of the senescence-associated β-galactosidase (SA-β-gal) and expression of senescence markers P16, P21, P53, TERT and TRF1. We found that YAP was highly expressed in old vascular tissues, inhibition and knockdown of YAP decreased senescence, while overexpression of YAP increased the senescence in both HUVECs and vascular tissues. In addition, autophagic flux blockage and mTOR pathway activation were observed during YAP-induced HUVECs and vascular senescence, which could be relieved by the inhibition and knockdown of YAP. Moreover, YAP-promoted cellular and vascular senescence could be relieved by mTOR inhibition. Collectively, our findings indicate that YAP may serve as a potential therapeutic target for ageing-associated cardiovascular disease.
| S-EPMC7810949 | biostudies-literature
Project description:Iron overload, a common clinical occurrence, is implicated in the metabolic syndrome although the contributing pathophysiological mechanisms are not fully defined. We show that prolonged iron overload results in an autophagy defect associated with accumulation of dysfunctional autolysosomes and loss of free lysosomes in skeletal muscle. These autophagy defects contribute to impaired insulin-stimulated glucose uptake and insulin signaling. Mechanistically, we show that iron overload leads to a decrease in Akt-mediated repression of tuberous sclerosis complex (TSC2) and Rheb-mediated mTORC1 activation on autolysosomes, thereby inhibiting autophagic-lysosome regeneration. Constitutive activation of mTORC1 or iron withdrawal replenishes lysosomal pools via increased mTORC1-UVRAG signaling, which restores insulin sensitivity. Induction of iron overload via intravenous iron-dextran delivery in mice also results in insulin resistance accompanied by abnormal autophagosome accumulation, lysosomal loss, and decreased mTORC1-UVRAG signaling in muscle. Collectively, our results show that chronic iron overload leads to a profound autophagy defect through mTORC1-UVRAG inhibition and provides new mechanistic insight into metabolic syndrome-associated insulin resistance.
| S-EPMC6776927 | biostudies-literature
Project description:Background: Although quiescence—reversible cell-cycle arrest—is a key part in the life history and fate of many mammalian cell types, the mechanisms of gene regulation in quiescent cells are poorly understood. We sought to clarify the role of microRNAs as regulators of the cellular functions of quiescent human fibroblasts. Results: Using microarrays, we discovered that the expression of the majority of profiled microRNAs differed between proliferating and quiescent fibroblasts. Fibroblasts induced into quiescence by contact inhibition or serum starvation had similar microRNA profiles, indicating common changes induced by distinct quiescence signals. By analyzing the gene expression patterns of microRNA target genes with quiescence, we discovered a strong regulatory function for miR-29, which is downregulated with quiescence. Using microarrays and immunoblotting, we confirmed that miR-29 targets genes encoding collagen and other extracellular matrix proteins and that those target genes are induced in quiescence. In addition, overexpression of miR-29 resulted in more rapid cell cycle re-entry from quiescence. We also found that let-7 and miR-125 were upregulated in quiescent cells. Overexpression of either one alone resulted in slower cell cycle re-entry from quiescence, while the combination of both together slowed cell cycle re-entry even further. Conclusions: microRNAs regulate key aspects of fibroblast quiescence including the proliferative state of the cells as well as their gene expression profiles, in particular, the induction of extracellular matrix proteins in quiescent fibroblasts. microRNAs in human neonatal dermal fibroblasts in 3 cell cycle conditions (proliferating, 4 days serum starved, 7 days contact inhibited) were analyzed by one color microarray. 3 separate fibroblast cell lines from different human donors were analyzed for each condition, with two separate labeling and hybridization samples for each cell line. In total, 18 samples were hybridized to the microRNA microarray.
2012-12-05 | E-GEOD-42593 | biostudies-arrayexpress
Project description:Background: Although quiescence—reversible cell-cycle arrest—is a key part in the life history and fate of many mammalian cell types, the mechanisms of gene regulation in quiescent cells are poorly understood. We sought to clarify the role of microRNAs as regulators of the cellular functions of quiescent human fibroblasts. Results: Using microarrays, we discovered that the expression of the majority of profiled microRNAs differed between proliferating and quiescent fibroblasts. Fibroblasts induced into quiescence by contact inhibition or serum starvation had similar microRNA profiles, indicating common changes induced by distinct quiescence signals. By analyzing the gene expression patterns of microRNA target genes with quiescence, we discovered a strong regulatory function for miR-29, which is downregulated with quiescence. Using microarrays and immunoblotting, we confirmed that miR-29 targets genes encoding collagen and other extracellular matrix proteins and that those target genes are induced in quiescence. In addition, overexpression of miR-29 resulted in more rapid cell cycle re-entry from quiescence. We also found that let-7 and miR-125 were upregulated in quiescent cells. Overexpression of either one alone resulted in slower cell cycle re-entry from quiescence, while the combination of both together slowed cell cycle re-entry even further. Conclusions: microRNAs regulate key aspects of fibroblast quiescence including the proliferative state of the cells as well as their gene expression profiles, in particular, the induction of extracellular matrix proteins in quiescent fibroblasts. mRNAs were analyzed by two color microarray from three separate human neonatal dermal fibroblasts cell lines transfected either with a miR-29b mimic or a control short dsRNA. One sample was labeled and analyzed in duplicate to ensure consistency in labeling and hybridization technique.
2012-12-05 | E-GEOD-42613 | biostudies-arrayexpress
Project description:The Greatwall-Endosulfine-PP2A/B55 pathway controls entry into quiescence by promoting translation of Elongator-tuneable transcripts
| PRJNA1124017 | ENA
Project description:Quiescence and limited dividing are critical in preserving potency of hematopoietic stem/progenitor cell (HSPCs) during lifetime, but little is known about how this process is regulated. Here, we show that the mobilized human HSPCs in peripheral blood (PB) are predominantly in a quiescent state, but rapidly exit quiescence and reduce repopulating potency in short-term culture. Through single cell RNA-seq, we identified a panel of regulators highly associated with HSC quiescence exit and cell-cycle entry. These regulators involve different biological processes such as cell-cycle, signaling pathways, metabolisms, etc. Among them, the oncogene, FOS restrains cell-cycle entry and supports repopulating potency in human HSCs through directly binding and regulating genes both for HSC quiescence and potency. Our findings uncover the regulatory program underlying quiescence exit and highlight the critical role of FOS to guard the quiescence and potency in human HSPCs.
2021-06-08 | GSE176316 | GEO
Project description:Quiescence and limited dividing are critical in preserving potency of hematopoietic stem/progenitor cell (HSPCs) during lifetime, but little is known about how this process is regulated. Here, we show that the mobilized human HSPCs in peripheral blood (PB) are predominantly in a quiescent state, but rapidly exit quiescence and reduce repopulating potency in short-term culture. Through single cell RNA-seq, we identified a panel of regulators highly associated with HSC quiescence exit and cell-cycle entry. These regulators involve different biological processes such as cell-cycle, signaling pathways, metabolisms, etc. Among them, the oncogene, FOS restrains cell-cycle entry and supports repopulating potency in human HSCs through directly binding and regulating genes both for HSC quiescence and potency. Our findings uncover the regulatory program underlying quiescence exit and highlight the critical role of FOS to guard the quiescence and potency in human HSPCs.
2021-06-08 | GSE176272 | GEO
Project description:Quiescence and limited dividing are critical in preserving potency of hematopoietic stem/progenitor cell (HSPCs) during lifetime, but little is known about how this process is regulated. Here, we show that the mobilized human HSPCs in peripheral blood (PB) are predominantly in a quiescent state, but rapidly exit quiescence and reduce repopulating potency in short-term culture. Through single cell RNA-seq, we identified a panel of regulators highly associated with HSC quiescence exit and cell-cycle entry. These regulators involve different biological processes such as cell-cycle, signaling pathways, metabolisms, etc. Among them, the oncogene, FOS restrains cell-cycle entry and supports repopulating potency in human HSCs through directly binding and regulating genes both for HSC quiescence and potency. Our findings uncover the regulatory program underlying quiescence exit and highlight the critical role of FOS to guard the quiescence and potency in human HSPCs.
2021-06-08 | GSE176317 | GEO