VEGFC/VEGFR3 Signaling Regulates Mouse Spermatogonial Cell Proliferation via the Activation of AKT/MAPK and Cyclin D1 Pathway and Mediates the Apoptosis by affecting Caspase 3/9 and Bcl-2

Abstract

We have previously shown that the transcript levels of Vegfc and its receptor Vegfr3 were high in spermatogonia and extremely low in spermatocytes and spermatids. However, it remains unknown about the functions and the mechanisms of VEGFC/VEGFR3 signaling in regulating the fate determinations of spermatogonia. To this end, here we explored the role and signaling pathways of VEGFC/VEGFR3 by using a cell line derived from immortalized mouse spermatogonia retaining markers of mitotic germ cells, namely GC-1 cells. VEGFR3 was expressed in mouse primary spermatogonia and GC-1 cells. VEGFC stimulated the proliferation and DNA synthesis of GC-1 cells and enhanced the phosphorylation of PI3K-AKT and MAPK, whereas LY294002 (an inhibitor for AKT) and CI-1040 (an inhibitor for MAPK) blocked the effect of VEGFC on GC-1 cell proliferation. Furthermore, VEGFC increased the transcripts of c-fos and Egr1 and protein levels of cyclin D1, PCNA and Bcl-2. Conversely, the blocking of VEGFC/VEGFR3 signaling by VEGFR3 knockdown reduced the phosphorylation of AKT/MAPK and decreased the levels of cyclin D1 and PCNA. Additionally, VEGFR3 knockdown not only resulted in more apoptosis of GC-1 cells but also led to a decrease of Bcl-2 and promoted the cleavage of Caspase-3/9 and PARP. Collectively, these data suggested that VEGFC/VEGFR3 signaling promotes the proliferation of GC-1 cells via the AKT /MAPK and cyclin D1 pathway and it inhibits the cell apoptosis through Caspase-3/9, PARP and Bcl-2. Thus, this study sheds a novel insight to the molecular mechanisms underlying the fate decisions of mammalian spermatogonia.

The Orexin-A-Regulated Akt/mTOR Pathway Promotes Cell Proliferation Through Inhibiting Apoptosis in Pancreatic Cancer Cells

“…Previous studies have described that orexin-A treatment can regulate theAkt/mTOR pathway in malignant tumors or tissues ( 24 , 28 ), encouraging us to clarify the mechanism of orexin-A-regulated cell proliferation in pancreatic cancer cells. Bcl-2 and caspase-9 are the key factors of cell apoptosis, which is also regulated by the Akt/mTOR signaling pathway ( 29 ). Additionally, the Akt/mTOR signaling pathway was also involved in c-myc-induced apoptosis in various tumors ( 30 , 31 ).…”

Expression of transcriptional factor EB (TFEB) in differentiating spermatogonia potentially promotes cell migration in mouse seminiferous epithelium

“…In a previous study, Chen et al performed a migration assay in immortalized spermatogonia, GC-1 cells [ 36 ]. Although it might lose some characteristics of normal spermatogonia, GC-1 cells are the most compatible cell line representing spermatogonia and are applied in many experiments to evaluate spermatogonia function in vitro [ 45 – 47 ]. Moreover, TFEB expressed in GC-1 cells also exhibited nucleus translocation following RA treatment (Additional file 1 : Figure S3), which was consistent with that in primary cultured spermatogonia.…”

miR-128在便秘发病中的作用及其机制

“…It was observed that compared with the control group, the expressions of both Bax and Caspase-3 were significantly increased, while the expression of Bcl-2 was markedly decreased in the miR-128 inhibitors transfected ICCs on both mRNA and protein level (Fig.3). inhibiting programmed cell death (21,22). Bax, a pro-apoptotic member of the Bcl-2 family, will move into the mitochondrial when cells in response to a wide variety of stimuli to cell apoptosis, which can urge Smac/DIABLO and Cytochrome c translocate from mitochondrial to cytoplasm (23).…”

“…In recent years, the studies of MicroRNAs (miRNAs) have become an area of focus. miRNAs are a group of non-coding small RNAs with the length of about [21][22][23] nucleotides. MiRNAs exert their function through binding to the 3′-untranslated region (UTR) of their target mRNAs, and consequentially inhibit the translation of their target genes.…”