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Project description:After sex specification during development, inappropriate sex maintenance in adults can lead to numerous defects and pathologies across many species. The molecular and cellular signals involved remain unknown. In the adult Drosophila testis, removing the JAK-STAT downstream effector Chinmo from adult somatic cyst stem cells (CySCs) causes their feminization, such that the sex-concordant interactions between male germ cells and the adjacent somatic cells are disrupted, causing gradual formation of testis germ cell tumors (GCT). Here we use single cell RNA-Seq to characterize cell-type specific transcriptional profiles for chinmo mutant testes undergoing sex transformation. This revealed both expected and novel mutant-specific cell populations and the full repertoire of transcriptomic changes accompanying sex transformation. Cell-cell communication networks were computed among all major cell types, revealing that feminized CySCs have reduced outgoing signaling to themselves and hub cells but elevated outgoing signaling including insulin signaling to germline stem cells (GSCs) /spermatogonia. Using Chinmo CUT & Tag, we identified Chinmo’s direct targets including the sex determination factor dsx and members of the insulin signaling pathway. We also found that Chinmo mainly functions as an activator in CySCs. By functional assays, we found ectopic expression of insulin pathway members in GSCs/spermatogonia phenocopies feminized chinmo mutant testes. In addition, knocking down insulin signaling in germ cells partially rescues the chinmo mutant phenotype. Altogether, we uncovered that Chinmo directly regulates canonical sex determination signals, as well as insulin signaling, to drive sex conversion of CySCs and germline tumorigenesis.
2024-08-28 | GSE201579 | GEO
Project description:After sex specification during development, inappropriate sex maintenance in adults can lead to numerous defects and pathologies across many species. The molecular and cellular signals involved remain unknown. In the adult Drosophila testis, removing the JAK-STAT downstream effector Chinmo from adult somatic cyst stem cells (CySCs) causes their feminization, such that the sex-concordant interactions between male germ cells and the adjacent somatic cells are disrupted, causing gradual formation of testis germ cell tumors (GCT). Here we use single cell RNA-Seq to characterize cell-type specific transcriptional profiles for chinmo mutant testes undergoing sex transformation. This revealed both expected and novel mutant-specific cell populations and the full repertoire of transcriptomic changes accompanying sex transformation. Cell-cell communication networks were computed among all major cell types, revealing that feminized CySCs have reduced outgoing signaling to themselves and hub cells but elevated outgoing signaling including insulin signaling to germline stem cells (GSCs) /spermatogonia. Using Chinmo CUT & Tag, we identified Chinmo’s direct targets including the sex determination factor dsx and members of the insulin signaling pathway. We also found that Chinmo mainly functions as an activator in CySCs. By functional assays, we found ectopic expression of insulin pathway members in GSCs/spermatogonia phenocopies feminized chinmo mutant testes. In addition, knocking down insulin signaling in germ cells partially rescues the chinmo mutant phenotype. Altogether, we uncovered that Chinmo directly regulates canonical sex determination signals, as well as insulin signaling, to drive sex conversion of CySCs and germline tumorigenesis.
2024-08-28 | GSE201673 | GEO
Project description:Chinmo maintains adult stem cell sex identity by directly regulating Doublesex and Insulin signaling
| PRJNA832745 | ENA
Project description:Chinmo maintains adult stem cell sex identity by directly regulating Doublesex and Insulin signaling [scRNA-seq]
| PRJNA832614 | ENA
Project description:Chinmo maintains adult stem cell sex identity by directly regulating Doublesex and Insulin signaling [CUT&Tag]
| PRJNA832257 | ENA
Project description:Little is known about the extracellular signaling factors that govern mammary stem cell behavior. Here, we identify CRIPTO and its cell-surface receptor GRP78 as regulators of stem cell behavior in isolated fetal and adult mammary epithelial cells. We develop a CRIPTO antagonist that promotes differentiation and reduces self-renewal of mammary stem cell-enriched populations cultured ex vivo. By contrast, CRIPTO treatment maintains the stem cell phenotype in these cultures and yields colonies with enhanced mammary gland reconstitution capacity. Surface expression of GRP78 marks CRIPTO-responsive, stem cell-enriched fetal and adult mammary epithelial cells, and deletion of GRP78 from adult mammary epithelial cells blocks their mammary gland reconstitution potential. Together, these findings identify the CRIPTO/GRP78 pathway as a developmentally conserved regulator of fetal and adult mammary stem cell behavior ex vivo, with implications for the stem-like cells found in many cancers.
| S-EPMC3986630 | biostudies-literature
Project description:Increasing evidence suggests that loss of β cell characteristics may cause insulin secretory deficiency in diabetes, but the underlying mechanisms remain unclear. Here, we show that Rfx6, whose mutation leads to neonatal diabetes in humans, is essential to maintain key features of functionally mature β cells in mice. Rfx6 loss in adult β cells leads to glucose intolerance, impaired β cell glucose sensing, and defective insulin secretion. This is associated with reduced expression of core components of the insulin secretion pathway, including glucokinase, the Abcc8/SUR1 subunit of KATP channels and voltage-gated Ca(2+) channels, which are direct targets of Rfx6. Moreover, Rfx6 contributes to the silencing of the vast majority of "disallowed" genes, a group usually specifically repressed in adult β cells, and thus to the maintenance of β cell maturity. These findings raise the possibility that changes in Rfx6 expression or activity may contribute to β cell failure in humans.
| S-EPMC4542305 | biostudies-literature
Project description:Hair follicles (HFs) undergo precisely regulated cycles of active regeneration (anagen), involution (catagen), and relative quiescence (telogen). Hair follicle stem cells (HFSCs) play important roles in regenerative cycling. Elucidating mechanisms that govern HFSC behavior can help uncover the underlying principles of hair development, hair growth disorders, and skin cancers. RNA-binding proteins of the Musashi (Msi) have been implicated in the biology of different stem cell types, yet they have not been studied in HFSCs. Here we utilized gain- and loss-of-function mouse models to demonstrate that forced MSI2 expression retards anagen entry and consequently delays hair growth, whereas loss of Msi2 enhances hair regrowth. Furthermore, our findings show that Msi2 maintains quiescent state of HFSCs in the process of the telogen-to-anagen transition. At the molecular level, our unbiased transcriptome profiling shows that Msi2 represses Hedgehog signaling activity and that Shh is its direct target in the hair follicle. Taken together, our findings reveal the importance of Msi2 in suppressing hair regeneration and maintaining HFSC quiescence. The previously unreported Msi2-Shh-Gli1 pathway adds to the growing understanding of the complex network governing cyclic hair growth.
| S-EPMC5581742 | biostudies-literature
Project description:Neural stem cells (NSCs) persist in the subventricular zone (SVZ) of the adult brain. Location within this germinal region determines the type of neuronal progeny NSCs generate, but the mechanism of adult NSC positional specification remains unknown. We show that sonic hedgehog (Shh) signaling, resulting in high gli1 levels, occurs in the ventral SVZ and is associated with the genesis of specific neuronal progeny. Shh is selectively produced by a small group of ventral forebrain neurons. Ablation of Shh decreases production of ventrally derived neuron types, while ectopic activation of this pathway in dorsal NSCs respecifies their progeny to deep granule interneurons and calbindin-positive periglomerular cells. These results show that Shh is necessary and sufficient for the specification of adult ventral NSCs.
| S-EPMC3346180 | biostudies-literature
Project description:Stem cell compartments in metazoa get regulated by systemic factors as well as local stem cell niche-derived factors. However, the mechanisms by which systemic signals integrate with local factors in maintaining tissue homeostasis remain unclear. Employing the Drosophila lymph gland, which harbors differentiated blood cells, and stem-like progenitor cells and their niche, we demonstrate how a systemic signal interacts and harmonizes with local factor/s to achieve cell type-specific tissue homeostasis. Our genetic analyses uncovered a novel function of Lar, a receptor protein tyrosine phosphatase. Niche-specific loss of Lar leads to upregulated insulin signaling, causing increased niche cell proliferation and ectopic progenitor differentiation. Insulin signaling assayed by PI3K activation is downregulated after the second instar larval stage, a time point that coincides with the appearance of Lar in the hematopoietic niche. We further demonstrate that Lar physically associates with InR and serves as a negative regulator for insulin signaling in the Drosophila larval hematopoietic niche. Whether Lar serves as a localized invariable negative regulator of systemic signals such as insulin in other stem cell niches remains to be explored.
| S-EPMC6955224 | biostudies-literature