The influence of prorenin/(pro)renin receptor on progesterone secretion by the bovine corpus luteum.

The aim of this study was to evaluate the role of prorenin/(pro)renin receptor activation on luteal progesterone (P4) secretion. Our hypothesis was that the nonproteolytic activation of (pro)renin receptor [P(RR)] is part of the regulatory mechanism responsible for corpus luteum (CL) function. In the first three experiments, prorenin was found to stimulate the production of P4, which is not inhibited by an angiotensin receptor antagonist (saralasin), but rather by a renin/prorenin inhibitor (aliskiren), a MAPK1/3 inhibitor (PD325901) or an EGFR inhibitor (AG1478), which are evidence of nonproteolytic activation of prorenin.

Molecular characteristics of oocytes and somatic cells of follicles at different sizes that influence in vitro oocyte maturation and embryo production.

During the last 10 to 15 yr, in vitro research to predict antral follicle growth and oocyte maturation has delivered interesting advances in the knowledge of processes regulating follicle growth and developmental competence of oocytes. This review discusses the contribution of cumulus and mural granulosa cells in the process of oocyte maturation and cumulus expansion in cumulus-oocyte complexes (COCs) from follicles of different sizes and shows that differences in gene expression in oocytes, granulosa, and theca cells of small and large follicles impact the success of in vitro blastocyst development. In addition, the molecular mechanisms by which COC metabolism and antioxidant defense provide oocyte competence are highlighted.

Activation of PPARG inhibits dominant follicle development in cattle.

The peroxisome proliferator-activated receptor gamma (PPARG, also called NR1C3) is a nuclear receptor of the peroxisome proliferator-activated receptor family (PPAR). PPARs are involved in the regulation of apoptosis, cell cycle, estradiol and progesterone synthesis, and metabolism. However, the role of PPARs and their regulation during follicular development and ovulation in monovular species remain poorly understood.

Expression of TNF-α system members in bovine ovarian follicles and the effects of TNF-α or dexamethasone on preantral follicle survival, development and ultrastructure in vitro.

This study was conducted to detect the protein expression of TNF-α system members (TNF-α/TNFR1/TNFR2) in bovine ovarian follicles and to evaluate the effects of TNF-α or dexamethasone on the survival and growth of primordial follicles in vitro, as well as on gene expression in cultured ovarian tissue. It was hypothesized that TNF-α induces follicular atresia in ovarian tissues cultured in vitro, and that dexamethasone suppresses the production of endogenous TNF-α, which can improve follicle viability in vitro. Ovarian fragments were cultured for 6days in α-MEM supplemented with TNF-α (0, 1, 10, 100 or 200ng/ml) or dexamethasone (0, 1, 10, 100 or 200ng/ml).

mRNA expression profile of the TNF-α system in LH-induced bovine preovulatory follicles and effects of TNF-α on gene expression, ultrastructure and expansion of cumulus-oocyte complexes cultured in vitro.

This study evaluated (1) the effects of in vivo GnRH treatment on mRNA expression of TNF-α system (TNF-α, TNFR1 and TNFR2) in granulosa cells of bovine preovulatory follicles, (2) the in vitro influence of gonadotropins on mRNA expression of TNF-α system in cultured cumulus cells, (3) the protein expression of the TNF-α system in late antral follicles and, (4) the influence of TNF-α on cumulus cells expansion, ultrastructure and on expression of HAS2, CASP3 and CASP6 in follicular cells cultured for 24 h. An increased expression of TNF-α and TNFR1 was observed after 3, 6 and 12 h of GnRH treatment when compared to 0 and 24h. Higher TNFR2 mRNA levels were observed 3, 6 and 12 h after GnRH, when compared to 0 and 24 h.

Mechanistic target of rapamycin is activated in bovine granulosa cells after LH surge but is not essential for ovulation.

The LH surge induces functional and morphological changes in granulosa cells. Mechanistic target of rapamycin (mTOR) is an integrator of signalling pathways in multiple cell types. We hypothesized that mTOR kinase activity integrates and modulates molecular pathways induced by LH in granulosa cells during the preovulatory period.

Effects of Adiponectin Including Reduction of Androstenedione Secretion and Ovarian Oxidative Stress Parameters In Vivo.

Adiponectin is the most abundantly produced human adipokine with anti-inflammatory, anti-oxidative, and insulin-sensitizing properties. Evidence from in vitro studies has indicated that adiponectin has a potential role in reproduction because it reduces the production of androstenedione in bovine theca cells in vitro. However, this effect on androgen production has not yet been observed in vivo.

Bovine ovarian cells have (pro)renin receptors and prorenin induces resumption of meiosis in vitro.

The discovery of a receptor that binds prorenin and renin in human endothelial and mesangial cells highlights the possible effect of renin-independent prorenin in the resumption of meiosis in oocytes that was postulated in the 1980s.This study aimed to identify the (pro)renin receptor in the ovary and to assess the effect of prorenin on meiotic resumption. The (pro)renin receptor protein was detected in bovine cumulus-oocyte complexes, theca cells, granulosa cells, and in the corpus luteum.

Protein and messenger RNA expression of interleukin 1 system members in bovine ovarian follicles and effects of interleukin 1β on primordial follicle activation and survival in vitro.

This study aimed to investigate the expression of interleukin 1 (IL-1) system members (proteins and messenger RNA of ligands and receptors) and its distribution in ovarian follicles of cyclic cows and to evaluate the effects of IL-1β on the survival and activation of primordial follicles in vitro. The ovaries were processed for localization of IL-1 system in preantral and antral follicles by immunohistochemical, real-time polymerase chain reaction, and Western blot analysis. For in vitro studies, ovarian fragments were cultured in α-MEM(+) supplemented with IL-1β (0, 1, 10, 50, or 100 ng/mL), and after 6 d, the cultured tissues were processed for histologic analysis.