Project description:To identify pathways regulating NSC quiescence, with a possible link to quiescence depth, we used double transgenic Tg(her4:drfp);Tg(mcm5:gfp) fish and paradigms predicted to highlight deep vs shallower quiescence. In adult fish (3 month-post-fertilization -mpf-), we performed bulk RNA sequencing on FACS sorted RFPhigh,GFPneg qNSCs (expressing strongly her4, signing NSCs transcriptionally remote from activation), and activated NSCs.
Project description:We generated a dataset in which we compared the bulk transcriptome of qNSCs between 1.5 and 3.5 mpf fish, stages between which deeper quiescence is progressively instated in order to find differences between deeply and shallow quiescent NSC
Project description:Bone morphogenetic protein-4 (BMP4) is involved in regulation of neural stem cells (NSCs) proliferation, differentiation, migration and survival. It was previously thought that the treatment of NSCs with BMP4 alone induces astrocytes, whereas the treatment of NSCs with the bFGF/BMP4 combination induces quiescent neural stem cells (qNSCs). In this study, we performed RNA sequencing (RNA-Seq) to compare the transcriptome profiles of BMP4-treated NSCs and bFGF/BMP4-treated NSCs, and found that both NSCs treated by these two methods were Sox2 positive qNSCs which were able to generate neurospheres. However, NSCs treated by those two methods exhibited different characteristics in state and the potential for neuronal differentiation based on transcriptome analysis and experimental results. We found that BMP4-treated NSCs tended to be in a deeper quiescent state than bFGF/BMP4-treated NSCs as the percentage of ki67-positive cells were lower in BMP4-treated NSCs. And after exposure to differentiated environment, bFGF/BMP4-treated NSCs generated more DCX-positive immature neurons and MAP2-positive neurons than BMP4-treated NSCs. Our study characterized qNSCs treated with BMP4 alone and bFGF/BMP4 combination, which laid a foundation for studying the activation mechanism of qNSCs.
Project description:Hierarchically organized tissues, such as hematopoietic systems, muscle, or skin harbor deeply quiescent stem cells which start proliferating in response to external insults. In contrast, it remains obscure whether similar quiescent cells exist in epithelia of digestive organs. Here we identified a deeply quiescent population in gastric corpus but not in other gastrointestinal organs after systematic examination of H2b-GFP label-retaining cells. The label-retaining cells in corpus epithelia belonged to a subpopulation of chief cells that were located near basal layers of corpus and did not overlap with Troyhigh, Lgr5high, or Misthigh cell population. The identified quiescent cells were marked with activation of Atf4 and unfolded protein response. External damages by indomethacin treatment triggered proliferation of the quiescent populations, indicating that chief cells of gastric corpus harbor deeply quiescent reserve cells with high levels of internal stress response activity.
Project description:We used microarrays to assess gene expression differences between proliferating adult NSCs/neural progenitors with and without active SIRT1.
Project description:We used microarrays to assess gene expression differences between proliferating adult NSCs/neural progenitors with and without active SIRT1. Adult NSCs/neural progenitors were isolated from 8 week old Sirt1lox/lox and NestinCre;Sirt1lox/lox mice (129SV strain), cultured for one passage in growth factors (EGF and bFGF) before isolation at early passage 2 for RNA extraction and hybridization on Affymetrix microarrays. Gene expression data were adjusted for background and normalized using RMA.
Project description:Adult neural stem cells (NSCs) must tightly regulate quiescence and proliferation. Single cell analysis has suggested a continuum of cell states as NSCs exit quiescence. Here we capture and characterize in vitro primed quiescent NSCs and identify LRIG1 as an important regulator. We show that BMP-4 signaling induces a dormant non-cycling quiescent state (d-qNSCs), whereas combined BMP-4/FGF-2 signalling induces a distinct primed quiescent state poised for cell cycle re-entry. Primed quiescent NSCs (p-qNSCs) are defined by high levels of LRIG1 and CD9, as well as an interferon response signature, and can efficiently engraft into the adult subventricular zone (SVZ) niche. Genetic disruption of Lrig1 in vivo within the SVZ NSCs leads an enhanced proliferation. Mechanistically, LRIG1 primes quiescent NSCs for cell cycle re-entry and EGFR responsiveness by enabling EGFR protein levels to increase but limiting signaling activation. LRIG1 is therefore an important functional regulator of NSC exit from quiescence.
Project description:Neural stem cells were sorted according to their activated or quiescent state by flow cytometry using a set of 3 markers (LeX, CD24 and EGFR) We used microarrays to detail the global programme of gene expression underlying the proliferation/quiescence balance.