In-vitro study of gonadotrophin signaling pathways in human granulosa cells in relation to progesterone receptor expression.

In humans, data on gonadotrophin-activated (LH, HCG and FSH) progesterone receptor expression and signalling pathways involved in matrix metalloproteinases (MMPs) expression presumably linked to the follicle rupture, are limited. Our hypothesis is LH, HCG and FSH increase progesterone receptor expression in granulosa cells through different signalling pathways, leading to an increased expression of ADAMTS-1 and MMP3/10, which may mediate follicular rupture through the transcription factor, HIF1A. Human granulosa cells were isolated from follicular aspirates obtained from 22 healthy women participating in our IVF programme for male-factor infertility. Progesterone receptor and HIF1A expression was assessed by immunofluorescence, and PKA-PKC-PI3K- ERK1/2, ADAMTS-1 and MMP3/10 expression by Western blot in pre-ovulatory and in cultured granulosa cells. Results show that HCG, LH and FSH regulate progesterone receptor expression and activate PKA, PKC, PI3K and ERK1/2 signalling pathways in granulosa cells but progesterone receptor expression is only mediated by PKA, PKC and ERK pathways. HCG, FSH and LH regulated MMPs expression through progesterone receptors. Moreover, HCG-progesterone-receptor-dependent HIF1A expression stimulated MMP3/10 expression but not that of ADAMTS-1. These results suggest differential downstream progesterone receptor signalling, as progesterone receptor regulates MMP3/10 expression via HIF1A, which is not involved in ADAMTS-1 expression.

Independent anti-angiogenic capacities of coagulation factors X and Xa.

Knockout models have shown that the coagulation system has a role in vascular development and angiogenesis. Herein, we report for the first time that zymogen FX and its active form (FXa) possess anti-angiogenic properties. Both the recombinant FX and FXa inhibit angiogenesis in vitro using endothelial EA.hy926 and human umbilical cord vascular endothelial cells (HUVEC). This effect is dependent on the Gla domain of FX. We demonstrate that FX and FXa use different mechanisms: the use of Rivaroxaban (RX) a specific inhibitor of FXa attenuated its anti-angiogenic properties but did not modify the anti-angiogenic effect of FX. Furthermore, only the anti-angiogenic activity of FXa is PAR-1dependent. Using in vivo models, we show that FX and FXa are anti-angiogenic in the zebrafish intersegmental vasculature (ISV) formation and in the chick embryo chorioallantoic membrane (CAM) assays. Our results provide further evidence for the non-hemostatic functions of FX and FXa and demonstrate for the first time a biological role for the zymogen FX.

Concanavalin-A induces granulosa cell death and inhibits FSH-mediated follicular growth and ovarian maturation in female rats.

Reproductive success stems from a finely regulated balance between follicular maturation and atresia, in which the role of carbohydrate structure is poorly understood. Here, we describe for the first time a fraction of purified recombinant human FSH that is capable of bringing about the cell death of granulosa cells and preventing follicular maturation in a rat model. Further analysis by mass spectrometry revealed the presence of the lectin Concanavalin-A (Con-A) within this fraction of recombinant FSH. Using both the fractionated FSH and Con-A, the observed cell death was predominantly located to the granulosa cells. Ex vivo culture of rat follicles demonstrated that follicle degeneration occurred and resulted in the release of a denuded and deteriorated oocyte. Moreover, in vivo experiments confirmed an increase in atresia and a corresponding reduction confined to follicle in early antral stage. As a mechanism of action, Con-A reduces ovarian proliferation, Von Willebrand staining, and angiogenesis. Based on the observation that Con-A may induce granulosa cell death followed by follicle death, our results further demonstrate that follicular carbohydrate moiety is changing under the influence of FSH, which may allow a carbohydrate-binding lectin to increase granulosa cell death. The physiological consequences of circulating lectin-like molecules remain to be determined. However, our results suggest a potential exploitation of carbohydrate binding in fertility and ovarian cancer treatment. This work may shed light on a key role of carbohydrates in the still obscure physiological process of follicular selection and atresia.