FSH receptor binding inhibitor influences estrogen production, receptor expression and signal pathway during in vitro maturation of sheep COCs

Multiomics Analyses Provide New Insight into Genetic Variation of Reproductive Adaptability in Tibetan Sheep

Domestication and artificial selection during production-oriented breeding have greatly shaped the level of genomic variability in sheep. However, the genetic variation associated with increased reproduction remains elusive. Here, two groups of samples from consecutively monotocous and polytocous sheep were collected for genome-wide association, transcriptomic, proteomic, and metabolomic analyses to explore the genetic variation in fecundity in Tibetan sheep. Genome-wide association study revealed strong associations between BMPR1B (p.Q249R) and litter size, as well as between PAPPA and lambing interval; these findings were validated in 1,130 individuals. Furthermore, we constructed the first single-cell atlas of Tibetan sheep ovary tissues and identified a specific mural granulosa cell subtype with PAPPA-specific expression and differential expression of BMPR1B between the two groups. Bulk RNA-seq indicated that BMPR1B and PAPPA expressions were similar between the two groups of sheep. 3D protein structure prediction and coimmunoprecipitation analysis indicated that mutation and mutually exclusive exons of BMPR1B are the main mechanisms for prolific Tibetan sheep. We propose that PAPPA is a key gene for stimulating ovarian follicular growth and development, and steroidogenesis. Our work reveals the genetic variation in reproductive performance in Tibetan sheep, providing insights and valuable genetic resources for the discovery of genes and regulatory mechanisms that improve reproductive success.

FSH promotes the proliferation of sheep granulosa cells by inhibiting the expression of TSP1

Thrombospondin (TSP1) plays an important role as an antiangiogenic factor in the reproductive system of female mammals. However, its expression and function in sheep are still unclear. In the present research, the Altay sheep (a native Chinese breed) was used to analyze the expression of TSP1 in the ovary and its potential function in granulosa cells. TSP1 was widely expressed in most tissues, as shown by qPCR. In the ovary, TSP1 mRNA expression decreased during follicular to luteal growth. The TSP1 protein was expressed in a wide variety of follicles of different diameters and localized to the cytoplasm and nucleus of granulosa cells. In in vitro studies, follicle-stimulating hormone (FSH) significantly inhibited the expression of TSP1 in sheep granulosa cells. Functionally, FSH- and TSP1-specific siRNAs can promote the proliferation of sheep granulosa cells. In contrast, TSP1 mimetic peptide, ABT510, offsets the proliferation of sheep granulosa cells. Different signaling pathway inhibitors all promoted FSH-inhibited TSP1 expression, but each inhibitor had different effects on TSP1. Among them, the PI3K and ERK pathway inhibitors significantly promoted TSP1 expression and inhibited the proliferation of sheep granulosa cells.

Effect of FSH on E2/GPR30-mediated mouse oocyte maturation in vitro

Mammalian oocyte restores meiosis can be stimulated by follicle-stimulating hormone (FSH) under normal physiological conditions. G-protein coupled receptor 30 (GPR30), an non-classical estrogen membrane receptor, has been widely reported in teleost oocyte maturation. However, it remains unknown whether GPR30 involves the role of FSH in mammalian cumulus expansion and oocyte maturation. Here, we used mouse cumulus-oocyte complexes (COCs) as a model to investigate how FSH affects the in vitro maturation of mouse oocytes mediated by 17β-estradiol (E₂)/GPR30signaling. Our study reveals that FSH starts regulating mouse cumulus expansion precisely at 8h in in vitro culture. ELISA measurement of E₂ levels in culture medium revealed that FSH activated aromatase to promote E₂ production in vitro in cultured mouse COCs. Moreover, the results of real-time quantitative PCR indicated that FSH-induced in vitro maturation of mouse oocytes was regulated by the estrogen-signaling pathway mediated by GPR30; FSH treatment markedly increased the mRNA expression of HAS2, PTGS2, and GREM1 in COCs. Exploration of the underlying mechanism suggested that E₂ produced by mouse COCs regulated the phosphorylation level of extracellular signal-regulated kinase 1/2 (ERK1/2) through GPR30 and thereby promoted mouse cumulus-cell expansion and oocyte maturation. In conclusion, our study reveals that FSH induced estrogen production in mouse COCs through aromatase, and that aromatase/GPR30/ERK1/2 signaling is involved in FSH-induced cumulus expansion.

FSH receptor binding inhibitor depresses carcinogenesis of ovarian cancer via decreasing levels of K-Ras, c-Myc and FSHR

The present study aimed to explore FSH receptor binding inhibitor (FRBI) effects on the levels of c-Myc, K-Ras and VEGF related to ovarian cancer, to evaluate the mRNA and protein levels of FSHR in the cumulus-oocyte complex (COCs). COCs were cultured for 24 h in the in vitro maturation (IVM) media replenished with 0, 10, 20, 30 and 40 μg/mL FRBI. Contents of c-Myc, K-Ras, VEGF, cAMP and IP3 in IVM media were detected with ELISA kits, respectively. The results indicated that the levels of FSHR protein and mRNA were determined with Western blotting. C-Myc contents of four FRBI + FSH-treated groups (COM groups) were reduced after IVM of COCs. C-Myc concentrations of COM-3 group was lower than the FSH group (p < .05). K-Ras and IP3 contents of COM-4 were decreased as compared to FSH group (p < .05). Expression levels of FSHR mRNAs and proteins in COM-4 group were smaller than that of FSH group. This study revealed that FRBI treatment could decrease c-Myc and K-Ras levels in the IVM medium fluids, and depress the FSHR levels of COCs. Expression levels of FSHR mRNAs and proteins of COM-4 group were significantly decreased. FRBI exerted its action via the signal pathway of IP3 and cAMP.

Receptor Binding Inhibitor Suppresses Carcinogenesis of Cervical Cancer by Depressing Levels of FSHR and ERβ in Mice

BACKGROUND

FSH Receptor Binding Inhibitor (FRBI) blocked the binding of FSH to FSHR. Our initial study revealed FRBI reduced the maturation rate, enhanced the apoptosis of sheep Cumulus-Oocyte Complex (COCs). Little is known about whether FRBI modulates ERβ and FSHR levels in the normal uterine and cancerous tissues. The present study aimed to evaluate the FRBI effects on the expressions of Estrogen Receptor-beta (ERβ) and FSH receptor (FSHR) in the uteri.

METHODS

150 mice were assigned to FRBI+FSH (COM), FSH and control groups (CG). Mice of COM-1, COM-2 and COM-3 groups were simultaneously intramuscularly injected with 500, 750 and 1000 µg FRBI with 10 IU FSH, respectively for five days. Western blotting and qPCR were utilized to determine the expression of ERβ and FSHR.

RESULTS

In comparison with FSH group, uterine lumen and glands of COM groups became narrow. The uterine wall and endometrial epithelium were thinned, and uterine lumen became narrow. Epithelial cells were decreased. Uterine wall thicknesses of COM-1, COM-2 and COM-3 groups were reduced by 6.49%, 14.89% and 15.69% on day 30 as compared with FSH group. Uterine perimetrium thicknesses of COM-1, COM-2 and COM-3 groups were reduced by 16.17%, 17.93% and 19.92% on day 20 in comparison with FSH group. Levels of FSHR mRNAs and proteins of COM-1, COM-2 and COM-3 groups were less than FSH group on days 20 and 30 (P<0.05). ERβ protein of COM-3 group was less than FSH group. Serum estradiol (E2) and FSH concentrations of COM-2 and COM-3 were lower than that of FSH group on day 30.

CONCLUSION

FRBI could decrease UWT and UPT, also block the uterine development, decline expression levels of ERβ and FSHR protein. Additionally, FRBI reduced the secretion of secretion of FSH and E2. Downregulating expression of FSHR and ERβ may be a potential treatment regimen for cervical cancer patients.

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

Mice of FRBI-1, FRBI-2, and FRBI-3 groups were intramuscularly injected with 20, 30, and 40mg/kg, respectively, for five consecutive days. Ovarian weights of three FRBI groups were reduced in comparison with FSH group. Ovarian cortex thicknesses (OCT) of the FRBI-3 group were less than that of the FSH group (P<0.05). As compared to FSH group, there were fewer numbers of secondary follicles (SFs) and mature follicles (MF) on the ovaries of FRBI-treated mice numbers of primary follicles (PFs) and SFs also decreased. In FRBI-3 mice, we found that the primordial follicles (POF) were scarcer, the follicles developed poorly, and granulosa cells became apoptosis. SF numbers of FRBI-2 and FRBI-3 groups were less than that of the FSH group on day 20 (P<0.05). Maximum longitudinal diameter (MLD) and transverse diameter (MTD) of three FRBI groups became decreased during the experiment. MLD and MTD of the FRBI-3 group were smaller than FSH group. Levels of FSHR mRNA and protein were less than that of CG and FSH group (P<0.05). ERα protein levels of FRBI group and serum concentrations of FSH and estradiol (E2) in the FRBI-treated mice were decreased when compared to CG and FSH group. In conclusion, FSH treatment could increase the numbers of SF and MF, enhance follicle development, reduce the numbers of SF and MF, and depress the follicular development of mice. Furthermore, FRBI declined the mRNA and protein levels of ERα and FSHR in the ovaries and dropped serum concentrations of FSH and E2 of mice.

FSH receptor binding inhibitor impacts K-Ras and c-Myc of ovarian cancer and signal pathway

The present study aimed to investigate FSHreceptor binding inhibitor (FRBI) effects on relative factors (K-Ras, c-Myc and Vascular endothelial growth factor (VEGF)) to ovarian cancer, and expression levels of FSH receptor (FSHR) mRNAs and proteins in the cumulus-oocyte complex (COCs), to determine changes of protein kinase A (PKA) in sheep granulosa cells, further to elucidate signaling pathway of FRBI action. COCs were cultured in vitro for 24h under supplementation of varying concentrations of FRBI (0, 10, 20, 30 and 40μg/mL) or FSH (10IU/mL). Concentrations of K-Ras, c-Myc, VEGF, cAMP and FSH were detected in IVM media fluids, respectively. The results showed that the concentrations of c-Myc, K-Ras and FSH of FRBI groups were gradually reduced with the increase of FRBI doses. VEGF level of the FRBI-4 group was significantly greater than control group (CG). Expression levels FSHR mRNA and protein and PKA of FRBI-3 and FRBI-4 groups were less than that of CG or FSH group (P<0.05 or P<0.01). Inositol trisphosphate (IP3) concentrations of FRBI-3 and FRBI-4 groups were less than FSH group (P<0.05). FRBI administration doses had significant negative correlations to levels or concentrations of K-Ras, c-Myc, VEGF, FSHR mRNA and protein and PKA protein. K-Ras had significant positive correlations with FSHR mRNA and protein and PKA protein. In conclusion, FRBI could promote the production of VEGF of sheep COCs. Higher doses of FRBI (30 and 40μg/mL) suppressed the production of c-Myc and K-Ras, and declined FSH concentrations in the IVM medium fluid, and decreased the expressions of FSHR at the gene and protein levels, additionally attenuated expression of PKA protein in the granulosa cells.