Role of ERK1/2 IN FSH-induced PCNA expression and steroidogenesis in granulosa cells

Abstract

Follicular development is characterized by both proliferation and differentiation of granulosa cells (GCs) under the control of FSH. However, the cellular mechanism by FSH is not known. Using cultured GCs, we examined whether FSH activated ERK1/2 was involved in the regulation of the proliferation related gene proliferating cell nuclear antigen (PCNA) and steroidogenesis. GCs were obtained from the ovaries of DES treated immature rats and cultured in serum free medium. The results showed that FSH activated ERK1/2 in a time dependent manner, with a peak at 20 min. Such activation was PKA dependent as was inhibited by specific inhibitors. FSH induced PCNA expression in a time dependent manner, with a maximum stimulation at 2 h. Similarly, StAR and steroid levels increased as FSH treatment time extended, with a maximum progesterone and StAR production at 48 h. ERK1/2 inactivation by UO126 inhibited the stimulatory effects of FSH on both PCNA and StAR expression and steroid synthesis in the GCs (p less than 0.01). Immunocytochemical studies further revealed that ERK1/2 inhibition led to a reduction of mitochondrial StAR in the GCs by FSH. These observations suggested that the stimulation of FSH on PCNA expression and steroidogenesis in GCs was mediated at least partially by ERK1/2.

Arsenic induced progesterone production in a caspase‐3‐dependent manner and changed redox status in preovulatory granulosa cells

“…In the present study, we found that in both cultured preovulatory GCs and immature female rats, the treatment of arsenite increased progesterone production which is an indicator of GC differentiation (Yu et al, 2005). Previous studies have reported that arsenic contributes to differentiation in leukemia cells (Nayak et al, 2010;Noh et al, 2010).…”

“…Yu et al (2005) demonstrated that steroidogenesis is a marker of GCs differentiation. Caspase-3 is required for the differentiation of skeletal muscle, embryonic Fig.…”

“…Yacobi et al reported that LH-induced caspase activation in cultured rat preovulatory follicles is coupled to mitochondrial steroidogenesis (De Vizcaya-Ruiz et al, 2009). In view of progesterone as a indicator of GC differentiation (Yu et al, 2005), we detected the activity of caspase-3 by Western blot and caspase-3 fluorometric assay. We found that the procaspase-3 and partial cleavage of caspase-3 21 kDa gradually elevated with doses of arsenite, and then they decreased at 10 mM (Fig.…”

Participation of Mitogen-Activated Protein Kinase in Luteinizing Hormone-Induced Differential Regulation of Steroidogenesis and Steroidogenic Gene Expression in Mural and Cumulus Granulosa Cells of Mouse Preovulatory Follicles1

“…The MAPK3/1-dependent pathway also has been reported as being involved in the regulation of steroidogenesis in granulosa cells; however, its precise role in this process is controversial. Some studies suggest that activation of MAPK is required for promoting steroidogenesis and steroidogenic gene expression in granulosa cells [36][37][38][39][40][41][42], whereas other studies indicate that activation of MAPK3/1 suppresses granulosa cell steroidogenesis and steroidogenic gene expression [38,[43][44][45]. Notably, most of the previous studies use either human luteinizing granulosa cells derived from patients receiving in vitro fertilization treatment or rat granulosa cells isolated from early antral follicles.…”

HOXA1-stimulated oncogenicity is mediated by selective upregulation of components of the p44/42 MAP kinase pathway in human mammary carcinoma cells

“…Endothelial PAS-domain protein 1 (EPAS1) is phosphorylated by p44/42 MAP kinase pathway, and is also involved in angiogenesis of human renal carcinoma (Conrad et al, 1999). Proliferating cell nuclear antigen (PCNA) has a pivotal role in the regulation of cell growth, acts as a prognostic factor of metastasis in breast cancer and is a substrate of p44/42 MAP kinase (Yu et al, 2005). The level of PCNA correlates directly with the rates of cellular proliferation and DNA synthesis (Prosperi, 1997).…”