Notch Signaling Regulates Differentiation and Steroidogenesis in Female Mouse Ovarian Granulosa Cells

Abstract

The Notch pathway is a highly conserved juxtacrine signaling mechanism that is important for many cellular processes during development, including differentiation and proliferation. Although Notch is important during ovarian follicle formation and early development, its functions during the gonadotropin-dependent stages of follicle development are largely unexplored. We observed positive regulation of Notch activity and expression of Notch ligands and receptors following activation of the luteinizing hormone-receptor in prepubertal mouse ovary. JAG1, the most abundantly expressed Notch ligand in mouse ovary, revealed a striking shift in localization from oocytes to somatic cells following hormone stimulation. Using primary cultures of granulosa cells, we investigated the functions of Jag1 using small interfering RNA knockdown. The loss of JAG1 led to suppression of granulosa cell differentiation as marked by reduced expression of enzymes and factors involved in steroid biosynthesis, and in steroid secretion. Jag1 knockdown also resulted in enhanced cell proliferation. These phenotypes were replicated, although less robustly, following knockdown of the obligate canonical Notch transcription factor RBPJ. Intracellular signaling analysis revealed increased activation of the mitogenic phosphatidylinositol 3-kinase/protein kinase B and mitogen-activated protein kinase/extracellular signal-regulated kinase pathways following Notch knockdown, with a mitogen-activated protein kinase kinase inhibitor blocking the enhanced proliferation observed in Jag1 knockdown granulosa cells. Activation of YB-1, a known regulator of granulosa cell differentiation genes, was suppressed by Jag1 knockdown. Overall, this study reveals a role of Notch signaling in promoting the differentiation of preovulatory granulosa cells, adding to the diverse functions of Notch in the mammalian ovary.

The Stemness of Human Ovarian Granulosa Cells and the Role of Resveratrol in the Differentiation of MSCs—A Review Based on Cellular and Molecular Knowledge

“…The Notch pathway in GCs originates from gonadotropin signals and is important for oocyte development. Kinase cascade activation by the Jag1 ligand promotes GC differentiation and inhibits proliferation [ 34 ].…”

Transcriptome profile of goat folliculogenesis reveals the interaction of oocyte and granulosa cell in correlation with different fertility population

“…In current investigation, we found that ligand-receptor pairs played important roles in goat folliculogenesis. Notch signaling pathway has been reported to be one of the most important pathways in folliculogenesis 38 . DLL3 , a ligand in Notch pathway, was highly expressed in oocytes, while another ligand in Notch pathways JAG2 was highly expressed in GCs compare with DLL3 and JAG1.…”

Gene regulation could be attributed to TCF3 and other key transcription factors in the muscle of pubertal heifers

“…In addition to classifying as a key TF, HES4 is a DEx gene in our muscle samples. Signalling by genes of the Hes family is important to mediate cell-cell communication, differentiation and steroidogenesis in ovarian granulosa cells (Kageyama, Ohtsuka, & Kobayashi, 2007;Prasasya & Mayo, 2017). Overexpression of HES4 leads to increased expression of RUNX2, one of our hub genes, which is critical to osteoblast differentiation (McManus et al, 2017).…”