FGF-independent MEK1/2 signalling in the developing foetal testis is essential for male germline differentiation in mice
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ABSTRACT:
SUBMITTER: Blucher R
PROVIDER: S-EPMC10696798 | biostudies-literature | 2023 Jan
REPOSITORIES: biostudies-literature
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Project description:Germline development provides the founding cells for spermatogenesis and oogenesis in males and females, respectively. Disrupted germline differentiation or compromised testis development can lead to subfertility or infertility and are strongly associated with testis cancer in humans. In mice, SRY and SOX9 induce expression of a range of genes, including Fgf9, that promote Sertoli cell differentiation and testis development. FGF9 is also thought to promote male germline differentiation but the pathway through which it signals is unknown. As FGFs signal through Mitogen-Activated Protein Kinases (MAPKs) in other tissues, we explored whether FGF9 regulates male germline development through MAPK by inhibiting either FGF or MEK1/2 signalling in fetal testis cultures from embryonic day (E)12.5, immediately after gonadal sex determination and testis cord formation, but prior to male germline commitment. Inhibition of MEK1/2 disrupted mitotic arrest, dysregulated a broad range of male germline development genes and prevented the upregulation of key male germline markers DPPA4 and DNMT3L. In contrast, when FGF signalling was inhibited, the male germline specific transcriptional program and the expression of male germline markers DPPA4 and DNMT3L were unaffected, and the germ cells entered mitotic arrest normally. While male germline development was not disrupted by FGF inhibition, a significant number of genes were commonly altered after 24h of FGF or MEK1/2 inhibition including genes involved in maintenance germline stem cells, Nodal signalling, proliferation, and germline cancer. Together, these data demonstrate a novel and essential role for MEK1/2 signalling in male germline differentiation, but a surprisingly limited role for FGF signalling. Our data strongly indicate that additional ligands act through MEK1/2 to promote male germline differentiation and highlight a need for further mechanistic understanding of male germline development.
2023-11-02 | GSE221453 | GEO
Project description:Germline development provides the founding cells for spermatogenesis and oogenesis in males and females, respectively. Disrupted germline differentiation or compromised testis development can lead to subfertility or infertility and are strongly associated with testis cancer in humans. In mice, SRY and SOX9 induce expression of a range of genes, including Fgf9, that promote Sertoli cell differentiation and testis development. FGF9 is also thought to promote male germline differentiation but the pathway through which it signals is unknown. As FGFs signal through Mitogen-Activated Protein Kinases (MAPKs) in other tissues, we explored whether FGF9 regulates male germline development through MAPK by inhibiting either FGF or MEK1/2 signalling in fetal testis cultures from embryonic day (E)12.5, immediately after gonadal sex determination and testis cord formation, but prior to male germline commitment. Inhibition of MEK1/2 disrupted mitotic arrest, dysregulated a broad range of male germline development genes and prevented the upregulation of key male germline markers DPPA4 and DNMT3L. In contrast, when FGF signalling was inhibited, the male germline specific transcriptional program and the expression of male germline markers DPPA4 and DNMT3L were unaffected, and the germ cells entered mitotic arrest normally. While male germline development was not disrupted by FGF inhibition, a significant number of genes were commonly altered after 24h of FGF or MEK1/2 inhibition including genes involved in maintenance germline stem cells, Nodal signalling, proliferation, and germline cancer. Together, these data demonstrate a novel and essential role for MEK1/2 signalling in male germline differentiation, but a surprisingly limited role for FGF signalling. Our data strongly indicate that additional ligands act through MEK1/2 to promote male germline differentiation and highlight a need for further mechanistic understanding of male germline development.
2023-11-21 | GSE221458 | GEO
Project description:FGF independent MEK1/2 signalling is essential for male germline development in mice [germ cell]
| PRJNA914327 | ENA
Project description:FGF independent MEK1/2 signalling is essential for male germline development in mice [somatic cell]
| PRJNA914333 | ENA
Project description:Developing tissues are sequentially patterned by extracellular signals that are turned on and off at specific times. In the zebrafish hindbrain, fibroblast growth factor (Fgf) signalling has different roles at different developmental stages: in the early hindbrain, transient Fgf3 and Fgf8 signalling from rhombomere 4 is required for correct segmentation, whereas later, neuronal Fgf20 expression confines neurogenesis to specific spatial domains within each rhombomere. How the switch between these two signalling regimes is coordinated is not known. We present evidence that the Zbtb16 transcription factor is required for this transition to happen in an orderly fashion. Zbtb16 expression is high in the early anterior hindbrain, then gradually upregulated posteriorly and confined to neural progenitors. In mutants lacking functional Zbtb16, fgf3 expression fails to be downregulated and persists until a late stage, resulting in excess and more widespread Fgf signalling during neurogenesis. Accordingly, the spatial pattern of neurogenesis is disrupted in Zbtb16 mutants. Our results reveal how the distinct stage-specific roles of Fgf signalling are coordinated in the zebrafish hindbrain.
| S-EPMC10508701 | biostudies-literature
Project description:Primordial germ cells (PGCs) and somatic cells originate from postimplantation epiblast cells in mice. As pluripotency is lost upon differentiation of somatic lineages, a naive epigenome and the pluripotency network are re-established during PGC development. Here we demonstrate that Prdm14 contributes not only to PGC specification, but also to naive pluripotency in embryonic stem (ES) cells by repressing the DNA methylation machinery and fibroblast growth factor (FGF) signalling. This indicates a critical role for Prdm14 in programming PGCs and promoting pluripotency in ES cells.
| S-EPMC3701237 | biostudies-literature
Project description:Testis development is critical for male fertility and continuation of the mammalian species. Essential structural components of testes are seminiferous tubules, which are lined by Sertoli cells and provide nutrients and physical protection for the maturation of sperm. Seminiferous tubule formation is initiated in embryos as testis cords and relies on their remodeling for maturation during development. Recently, three-dimensional image analyses showed that testis cords in different parts of embryonic gonads undergo distinct remodeling processes. How this asymmetric remodeling is regulated has not been investigated. We report here that the absence of an adhesion G protein-coupled receptor, GPR56, leads to partial disruption of seminiferous tubules and reduced fertility in male mice. The defects appear to originate asymmetrically in embryonic gonads, but subsequent to the initial establishment of testis cords, suggesting that GPR56 might act to establish a spatial and/or temporal cue for asymmetric cord remodeling during male gonad development.
| S-EPMC2991479 | biostudies-literature
Project description:BackgroundMale germline stem cells (mGSCs) offer great promise in regenerative medicine and animal breeding due to their capacity to maintain self-renewal and to transmit genetic information to the next generation following spermatogenesis. Human testis-derived embryonic stem cell-like cells have been shown to possess potential of mesenchymal progenitors, but there remains confusion about the characteristics and origin of porcine testis-derived stem cells.MethodsPorcine testis-derived stem cells were obtained from primary testicular cultures of 5-day old piglets, and selectively expanded using culture conditions for long-term culture and induction differentiation. The stem cell properties of porcine testis-derived stem cells were subsequently assessed by determining the expression of pluripotency-associated markers, alkaline phosphatase (AP) activity, and capacity for sperm and multilineage differentiation in vitro. The gene expression profile was compared via microarray analysis.ResultsWe identified two different types of testis-derived stem cells (termed as C1 and C2 here) during porcine testicular cell culture. The gene expression microarray analysis showed that the transcriptome profile of C1 and C2 differed significantly from each other. The C1 appeared to be morphologically similar to the previously described mouse mGSCs, expressed pluripotency- and germ cell-associated markers, maintained the paternal imprinted pattern of H19, displayed alkaline phosphatase activity, and could differentiate into sperm. Together, these data suggest that C1 represent the porcine mGSC population. Conversely, the C2 appeared similar to the previously described porcine mGSCs with three-dimensional morphology, abundantly expressed Leydig cell lineage and mesenchymal cell-specific markers, and could differentiate into testosterone-producing Leydig cells, suggesting that they are progenitor Leydig cells (PLCs).ConclusionCollectively, we have established the expected characteristics and markers of authentic porcine mGSCs (C1). We found for the first time that, the C2, equivalent to previously claimed porcine mGSCs, are actually progenitor Leydig cells (PLCs). These findings provide new insights into the discrepancies among previous reports and future identification and analyses of testis-derived stem cells.
| S-EPMC6052628 | biostudies-literature
Project description:BackgroundAbnormalities of in utero testis development are strongly associated with reproductive health conditions, including male infertility and testis cancer. In mouse testes, SOX9 and FGF9 support Sertoli cell development, while VEGF signalling is essential for the establishment of vasculature. The mitogen-activated protein kinase (MAPK) pathway is a major signalling cascade, essential for cell proliferation, differentiation and activation of Sry during primary sex-determination, but little is known about its function during fetal testis morphogenesis. We explored potential functions of MAPK signalling immediately after the establishment of testis cords in embryonic day (E)12.5 Oct4-eGFP transgenic mouse testes cultured using a MEK1/2 inhibitor.ResultsRNA sequencing in isolated gonadal somatic cells identified 116 and 114 differentially expressed genes after 24 and 72 h of MEK1/2 inhibition, respectively. Ingenuity Pathway Analysis revealed an association of MEK1/2 signalling with biological functions such as angiogenesis, vasculogenesis and cell migration. This included a failure to upregulate the master transcriptional regulators of vascular development, Sox7 and Sox17, VEGF receptor genes, the cell adhesion factor gene Cd31 and a range of other endothelial cell markers such as Cdh5 (encoding VE-cadherin) and gap junction genes Gja4 and Gja5. In contrast, only a small number of Sertoli cell enriched genes were affected. Immunofluorescent analyses of control testes revealed that the MEK1/2 downstream target, ERK1/2 was phosphorylated in endothelial cells and Sertoli cells. Inhibition of MEK1/2 eliminated pERK1/2 in fetal testes, and CD31, VE-cadherin, SOX7 and SOX17 and endothelial cells were lost. Consistent with a role for VEGF in driving endothelial cell development in the testis, inhibition of VEGFR also abrogated pERK1/2 and SOX7 and SOX17 expressing endothelial cells. Moreover, while Sertoli cell proliferation and localisation to the testis cord basement membrane was disrupted by inhibition of MEK1/2, it was unaffected by VEGFR inhibition. Instead, inhibition of FGF signalling compromised Sertoli cell proliferation and localisation to the testis cord basement membrane.ConclusionsTogether, our data highlight an essential role for VEGF-dependent MEK1/2 signalling in promoting vasculature and indicate that FGF signalling through MEK1/2 regulates Sertoli cell organisation in the developing mouse testis.
| S-EPMC11445939 | biostudies-literature
Project description:Postnatal spermatogonial stem cells (SSCs) progress through proliferative and developmental stages to populate the testicular niche prior to productive spermatogenesis. To better understand, we conducted extensive genomic profiling at multiple postnatal stages on subpopulations enriched for particular markers (THY1, KIT, OCT4, ID4, or GFRa1). Overall, our profiles suggest three broad populations of spermatogonia in juveniles: (1) epithelial-like spermatogonia (THY1(+); high OCT4, ID4, and GFRa1), (2) more abundant mesenchymal-like spermatogonia (THY1(+); moderate OCT4 and ID4; high mesenchymal markers), and (3) (in older juveniles) abundant spermatogonia committing to gametogenesis (high KIT(+)). Epithelial-like spermatogonia displayed the expected imprinting patterns, but, surprisingly, mesenchymal-like spermatogonia lacked imprinting specifically at paternally imprinted loci but fully restored imprinting prior to puberty. Furthermore, mesenchymal-like spermatogonia also displayed developmentally linked DNA demethylation at meiotic genes and also at certain monoallelic neural genes (e.g., protocadherins and olfactory receptors). We also reveal novel candidate receptor-ligand networks involving SSCs and the developing niche. Taken together, neonates/juveniles contain heterogeneous epithelial-like or mesenchymal-like spermatogonial populations, with the latter displaying extensive DNA methylation/chromatin dynamics. We speculate that this plasticity helps SSCs proliferate and migrate within the developing seminiferous tubule, with proper niche interaction and membrane attachment reverting mesenchymal-like spermatogonial subtype cells back to an epithelial-like state with normal imprinting profiles.
| S-EPMC4647563 | biostudies-literature