Anti-Müllerian Hormone Regulates Stem Cell Factor via cAMP/PKA Signaling Pathway in Human Granulosa Cells by Inhibiting the Phosphorylation of CREB

Anti-Müllerian hormone (AMH) downregulates the level of stem cell factor (SCF) via the cAMP/PKA signaling pathway in human granulosa cells (GCs). Little information is available on the molecular mechanism underlying the interaction. This study is aimed at determining whether AMH regulates expression of SCF via the cAMP-PKA-CREB signaling pathway in human GCs. In the present study, we verified the binding of cAMP-response element-binding protein (CREB) to promoter of SCF in human GCs. Furthermore, the effect of CREB was tested on the SCF promoter, and the site of CREB binding to SCF promoter was identified using truncations as well as assays of SCF-promoted mutation and CREB mutation. To investigate the correlation among AMH, SCF promoter, and CREB, pGL-Basic-SCF+CREB was transfected into overexpressed AMH GCs (AMH-high GCs), low expressed AMH GCs (AMH-low GCs), and normal GCs (GCs), respectively. Finally, immunofluorescence, double immunostaining, and Western blot were carried out in AMH-high and AMH-low GCs to confirm the AMH-mediated regulation of SCF expression by inhibiting the phosphorylation of CREB (pCREB) in GCs. Results indicated CREB interacted with SCF promoter and significantly enhanced the transcription level of SCF. The CREB binding site was localized at 318-321 bp of SCF gene promote. AMH inhibits the expression of SCF by phosphorylation of CREB via the PKA signaling pathway in GCs. These findings provide an in-depth understanding of the molecular mechanism underlying AMH suppressing the follicle growth, which would aid in the development of a novel therapy.