MON-232 Differential Regulation of Genes Relevant to Reproductive Function in Human Granulosa Cells of Small Antral Follicles from Women with or without Polycystic Ovary Syndrome

Introduction: Polycystic Ovary Syndrome (PCOS) is the most common endocrinopathy in young women, affecting 5-10% of women of reproductive age. Despite its high prevalence, the underlying pathogenesis of PCOS remains complex and incompletely understood. Aberrant function of granulosa cells has been implicated in the aetiology of PCOS. Material and methods: Granulosa cells (GCs) were obtained from follicular fluid from (unstimulated) individual small antral follicles (SAF) isolated at the time of removal of ovarian tissue for fertility cryopreservation in young women. Granulosa luteal (GL) cells were collected from pooled follicular fluid collected at the time of oocyte retrieval in women undergoing IVF. RNA was extracted and RT-qPCR carried out to analyse expression of genes involved in granulosa cell function, including steroidogenesis and growth. 30 GC samples from individual small antral follicles from 15 women with regular cycles and 31 samples from 10 women with PCOS were included. Mean follicle size was similar between groups (mean 5.5±1mm). Luteinised GCs (GLCs) from 8 women with and without PCOS were also included. Results: 92% of GC samples from SAF expressed LH receptor (LHCGR) RNA. Expression of LHCGR was not significantly higher in PCOS GCs but there was a difference in distribution of results with a subset of PCOS samples (13%) with 4-6 times higher expression than in that of the controls. LHCGR expression was higher in GLCs compared to GCs (P<0.05). FSH receptor (FSHR) expression was significantly lower in PCOS GCs from SAFs (P<0.05), unlike PCOS GLCs, which expressed higher levels of FSHR (p<0.05). FSHR expression was 14 fold higher in GCs compared to GLCs (p<0.0001). There was no correlation between LHCGR, FSHR or follicle size. Androgen receptor (AR) expression was lower in PCOS GCs from SAF (p<0.01) unlike PCOS GLCs, which expressed more AR than GL controls (P<0.05). AR expression correlated with FSHR (p<0.0001) but not LHCGR. CYP11A1 was lower in both PCOS GCs and GLCs (p<0.05) and expression was 50 fold higher in GLCs than GCs (p<0.0001). Expression of 3BHSD2 was reduced in PCOS GCs (p=0.06). There were no significant differences in expression of STAR, CYP19, INHBA or INHBB between control and PCOS in either GCs or GLCs. Conclusions: Granulosa cells from small antral follicles from women with PCOS have a lower expression of FSHR, AR and CYP11A1 and a trend towards higher LHCGR compared to controls. This expression pattern is suggestive of early luteinisation of granulosa cells in unstimulated small antral follicles in PCOS.