Description
Bone morphogenetic proteins (BMP) are firmly implicated as intra-ovarian regulators of follicle development and steroidogenesis. We carried out a microarray analysis to examine global changes in gene expression in bovine theca cells in response to treatment with BMP6 alone and in combination with LH. There was a major effect of BMP6 treatment on the gene expression profile with a much weaker effect of LH. None of these differences in response to LH treatment was found to be statistically significant after applying Benjamini-Hochberg correction. BMP6 significantly (>2-fold; P<0.01) up- or down-regulated expression of 445 genes. Insulin-like peptide 3 (INSL3) was the most heavily down-regulated gene (-43-fold) with CYP17A1 and other key transcripts involved in TC steroidogenesis including LHCGR, INHA, STAR, CYP11A1 and HSD3B1 also down-regulated. BMP6 also reduced expression of NR5A1 encoding steroidogenic factor-1 known to target the promoter regions of the aforementioned genes. Real-time PCR confirmed these findings and also revealed a marked reduction in expression of INSL3 receptor (RXFP2). Secretion of INSL3 protein and androstenedione were also suppressed suggesting a functional link between BMP and INSL3 pathways in controlling androgen synthesis.