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


METHODS
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.


RESULTS
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.


CONCLUSIONS
Ar and Ep serve as pro-survival LH mediators in the human corpus luteum.
Department of Molecular Cell Biology, Weizmann Institute of Science, Rehovot, Israel. idorit@netvision.net.il
I
I
Ben-Ami
L
L
Armon
S
S
Freimann
D
D
Strassburger
R
R
Ron-El
A
A
Amsterdam
D000328:Adult; D066258:Amphiregulin; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D015153:Blotting, Western; D066255:EGF Family of Proteins; D004815:Epidermal Growth Factor / Q000096:biosynthesis / Q000494:pharmacology / Q000502:physiology*; D066260:Epiregulin; D005260:Female; D005307:Fertilization in Vitro; D015870:Gene Expression / Q000187:drug effects; D006023:Glycoproteins / Q000096:biosynthesis / Q000494:pharmacology / Q000502:physiology*; D006801:Humans; D020287:In Situ Nick-End Labeling; D036341:Intercellular Signaling Peptides and Proteins / Q000096:biosynthesis / Q000494:pharmacology / Q000502:physiology*; D008184:Luteal Cells / Q000502:physiology*; D007986:Luteinizing Hormone / Q000494:pharmacology / Q000502:physiology*; D020935:MAP Kinase Signaling System / Q000187:drug effects; D011374:Progesterone / Q000096:biosynthesis; D012333:RNA, Messenger / Q000378:metabolism; D013997:Time Factors
C587848:AREG protein, human; D066258:Amphiregulin; D066255:EGF Family of Proteins; C587880:EREG protein, human; D066260:Epiregulin; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D012333:RNA, Messenger; D011374:Progesterone; D004815:Epidermal Growth Factor; D007986:Luteinizing Hormone