THE INFLUENCE OF POLYCYSTIC OVARY SYNDROME ON OVARIAN GENE EXPRESSION
AJ Leonard1, IM Evans2, E El Mahdi1, AK Sinha2, RP Ekins2 & P Hardiman1
Almost 70 years after Polycystic ovary syndrome (PCOS) was first described, its etiology remains unclear. In this preliminary study, gene expression in 3 normal and 3 PCOS ovaries was compared using differential display PCR to probe for genes with roles in the pathogenesis of PCOS.
Over 1700 PCR products were detected with the 21 primer combinations used, each potentially derived from a different mRNA species. Pattern comparison of PCR products from normal and PCOS ovary revealed 34 PCR products which exhibited differential expression, 12 being over expressed in PCOS and 22 under-expressed. Band identification by DNA sequencing is on-going. Early results show the 2 similarly sized PCR products over-expressed in PCOS ovary were derived from the 3' end of alpha2 (smooth muscle) actin mRNA.
Semi-quantitative RT-PCR using transcript-specific primers was used to verify differential expression of this gene in the experimental samples. Alpha2 actin expression (versus 18S rRNA) was elevated more than 15-fold (P < 0.001; n = 3) in PCOS ovary relative to normal ovary. Furthermore, preliminary western blotting analysis of ovarian protein extracts from another sample set indicated that alpha2 actin protein abundance was also elevated in PCOS ovary compared with normal ovary, whereas alpha1 actin and alpha tubulin protein abundance was unaffected.
These results indicate that ovarian gene expression is modified in PCOS - approximately 2% of expressed genes may be disturbed, though each mRNA species may be represented by more than one PCR product in this differential display study. The specific and substantial elevation in alpha2 (smooth muscle) actin abundance may be a consequence of stromal hyperplasia. Analysis of the other differentially expressed gene products may reveal genes/proteins which are more intimately associated with the pathophysiology of PCOS and may provide targets for therapeutic intervention and/or diagnostic testing.