EGF-like growth factors as LH mediators in the human corpus luteum

This study aims to investigate the role of epidermal growth factor-like ligands, amphiregulin (Ar) and epiregulin (Ep), in regulation of apoptosis in luteinized human granulosa cells. Luteinized human granulosa cells were obtained from women undergoing IVF treatment. Ar and Ep mRNA levels were measured by real-time RT-PCR. The rate of apoptosis was measured by TUNEL. Progesterone levels were measured using radioimmunoassay. Ar- and Ep-induced activation of signaling cascades and Ar protein levels were detected by western blotting. LH stimulation of luteinized human granulosa cells induced biosynthesis of Ar and Ep mRNA in a time-dependent manner. The blockade of MEK (by U0126) reduced the expression of LH-induced Ar and Ep biosynthesis. Incubation of the cells with Ar and Ep completely abolished the increase in apoptosis rate induced by serum starvation, and concomitantly caused a pronounced increase in progesterone production. Stimulation of the cells with Ar and Ep also activated the ERK and AKT signaling cascades. Finally, we demonstrated that the pro-survival effect of Ar and Ep is partially dependent on their ability to induce progesterone production. Ar and Ep serve as pro-survival LH mediators in the human corpus luteum.