Determine the Role of FSH Receptor Binding Inhibitor in Regulating Ovarian Follicles Development and Expression of FSHR and ERα in Mice

BMP15 regulates FSHR through TGF-β receptor II and SMAD4 signaling in prepubertal ovary of Rongchang pigs

Bone morphogenetic protein 15 (BMP15) and follicle-stimulating hormone (FSH) both play important roles in mammalian ovary and follicular development. The aim of the present study is to investigate the effects of BMP15 and FSH in the prepubertal ovary of Rongchang pigs considering a possible signaling mechanism involving TβRII/ SMAD4 and FSHR in granulosa cells. For this purpose, we quantified expression levels of BMP15, SMAD2, SMAD3, SMAD4, SMAD7, TGF-β1, TGF-β2, TGF-β3, TGFβRI, TGFβRII, and FSHR via qRT-PCR at different ages in prepubertal ovaries and cultured biopsy of 90-day-old ovary in Rongchang pig. Additionally, the protein levels of BMP15, FSHR, SMAD2, SMAD4, TGFβRI, TGFβRII, TGF-β1, TGF-β2 were quantified via Western blot and the localizations of BMP15, FSHR and TGFβRII were observed via immunofluorescence confocal microscope. The results showed that expression levels of BMP15, TGF-β1, TGFβRII and FSHR increased significantly at day 60 as compared to day 30 and reached peak value at day 90 in prepubertal ovary of Rongchang pigs. We observed that BMP15, TGFβRII and FSHR was highly presented, which TGFβRII and FSHR displayed co-localization in the follicles of the prepubertal ovaries of 90-day-old Rongchang gilts. Treatment with TGFβRI/II inhibitor LY2109761 significantly decreased the expression of TGFβRI, TGFβRII and SMAD4 and TGFβRI inhibitor LY2157299 decreased TGFβRI, but increased the TGFβRII, SMAD4 and FSHR expression levels. Furthermore, the addition of rBMP15 and rFSH group significantly increased the expression of TGFβRII and FSHR proteins (P < 0.01), but no significant change in the expression of TGFβRI (P > 0.05) was observed by Western blot. In conclusion, BMP15, TGFβRII and FSHR were increased significantly in the prepubertal ovarian follicles of Rongchang pigs and FSHR expression in GCs was regulated by BMP15 and FSH through the TGFβRII.

Follicle-stimulating hormone regulates glycolysis of water buffalo follicular granulosa cells through AMPK/SIRT1 signalling pathway

Glycolysis in follicular granulosa cells (GCs) is the primary source of energy metabolism substrate of oocytes and is closely related to follicular development in mammals. Many physiological functions of GCs are regulated by follicle-stimulating hormone (FSH). In contrast, whether FSH regulates the glycolysis of GCs and its mechanism remains unclear. This study explored the correlation between FSH concentration and glycolysis level of GCs from different diameters of water buffalo follicles, and further explored the mechanism of FSH regulation in glycolysis in vitro cultured GCs. Results showed the variation trend of lactic acid concentration in follicular fluid and the expression level of glycolysis-related genes in GCs were consistent with the variation trend of FSH concentration in follicular fluid from follicles with different diameters. When GCs were treated with FSH in vitro, the expression level of glycolysis-related genes, lactate production and glucose uptake increased correspondingly (p < .05). Furthermore, we found that expression trend of AMPK/Sirtuin1 (SIRT1) pathway-related genes in GCs was consistent with the expression trend of glycolysis-related genes and was positively correlated with FSH concentrations in vivo or cultured in vitro. Activation of SIRT1 increased the expression level of glycolytic key proteins and lactic acid production in GCs, while inhibition of SIRT1 showed the opposite effect. In general, glycolysis in water buffalo GCs in vivo or cultured in vitro was positively correlated with FSH concentration. AMPK/SIRT1 pathway plays an important role in the regulation of FSH on glycolysis in GCs. Our findings will enrich the understanding of FSH regulating the development of water buffalo follicles.

The Effects of Zearalenone on the Localization and Expression of Reproductive Hormones in the Ovaries of Weaned Gilts

This study aims to investigate the effects of zearalenone (ZEA) on the localizations and expressions of follicle stimulating hormone receptor (FSHR), luteinizing hormone receptor (LHR), gonadotropin releasing hormone (GnRH) and gonadotropin releasing hormone receptor (GnRHR) in the ovaries of weaned gilts. Twenty 42-day-old weaned gilts were randomly allocated into two groups, and treated with a control diet and a ZEA-contaminated diet (ZEA 1.04 mg/kg), respectively. After 7-day adjustment, gilts were fed individually for 35 days and euthanized for blood and ovarian samples collection before morning feeding on the 36th day. Serum hormones of E₂, PRG, FSH, LH and GnRH were determined using radioimmunoassay kits. The ovaries were collected for relative mRNA and protein expression, and immunohistochemical analysis of FSHR, LHR, GnRH and GnRHR. The results revealed that ZEA exposure significantly increased the final vulva area (p < 0.05), significantly elevated the serum concentrations of estradiol, follicle stimulating hormone and GnRH (p < 0.05), and markedly up-regulated the mRNA and protein expressions of FSHR, LHR, GnRH and GnRHR (p < 0.05). Besides, the results of immunohistochemistry showed that the immunoreactive substances of ovarian FSHR, LHR, GnRH and GnRHR in the gilts fed the ZEA-contaminated diet were stronger than the gilts fed the control diet. Our findings indicated that dietary ZEA (1.04 mg/kg) could cause follicular proliferation by interfering with the localization and expression of FSHR, LHR, GnRH and GnRHR, and then affect the follicular development of weaned gilts.

Central residues of FSHβ (89-97) peptide are not critical for FSHR binding: Implications for peptidomimetic design

In our previous study, we had identified a 9-mer peptide (FSHβ (89-97)) derived from seat belt loop of human FSHβ and demonstrated its ability to function as FSHR antagonist in vivo. Structure analysis revealed that the four central residues ⁹¹STDC⁹⁴ within this peptide may not be critical for receptor binding. In the present study, ⁹¹STDC⁹⁴ residues were substituted with alanine to generate ΔFSHβ 89-97(⁹¹STDC⁹⁴/AAAA) peptide. Analogous to the parent peptide, ΔFSHβ 89-97(⁹¹STDC⁹⁴/AAAA) peptide inhibited binding of iodinated FSH to rat FSHR and reduced FSH-induced cAMP production. The peptide could impede granulosa cell proliferation leading to reduction in FSH-mediated ovarian weight gain in immature female rats. In these rats, peptide administration further downregulated androgen receptor and estrogen receptor-alpha expression and upregulated estrogen receptor-beta expression. The results indicate that substitution of ⁹¹STDC⁹⁴ with alanine did not significantly alter FSHR antagonist activity of FSHβ (89-97) peptide implying that these residues are not critical for FSH-FSHR interaction and can be replaced with non-peptidic moieties for development of more potent peptidomimetics.