Endocrine Abstracts

Follicle-stimulating hormone receptor (FSHR) is a Class A G protein-coupled receptor (GCPR) that is essential in reproduction. Interactions with its heterodimeric glycoprotein hormone, FSH, activates the cAMP/PKA signalling pathway, which induces steroidogenic activity and granulosa cell proliferation to support ovarian follicle growth and survival. Moreover, a number of ageing-related extragonadal roles of FSH/FSHR have been proposed, with menopausal elevation in FSH linked to bone loss, deposition/changes in adipose tissue depots, and Alzheimer’s disease. Thus, targeted inhibition of FSH/FSHR is an attractive approach to combat these menopause-related co-morbidities, furthermore, would present a non-steroidal mechanism of contraception. Therefore, we aimed to screen and identify novel FSHR antagonists and investigate their effects on FSHR-induced second messenger pathway activation. Using human embryonic kidney 293 (HEK293) cells transiently expressing the FSHR, 84 AI-generated small molecule compounds (provided by Atomwise, San Francisco) were screened for the ability to inhibit FSH-dependent cAMP-production. 3 inhibitors were identified, showing <90% inhibition at high FSH concentration, with an IC50 value ranging between 35-65µM. Next, concentration-dependent assessment of the inhibitors (0-100µM) on FSH-dependent cAMP-production was analysed. Analysis suggested that these inhibitors displayed non-competitive antagonism, as there were no obvious changes in potency. Our findings present 4 new small molecule pharmacological non-competitive FSHR inhibitors, which may present new pathways for non-steroidal contraceptives or treatment of menopause-related co-morbidities.