Effect of the Methoxychlor Metabolite HPTE on the Rat Ovarian Granulosa Cell Transcriptome in Vitro

Ovarian granulosa cells play a central role in steroidogenesis, which is critical for female reproduction. Follicle-stimulating hormone (FSH) promotes cAMPmediated signaling to regulate granulosa cell steroidogenesis. We have shown previously that 2, 2-bis-(p-hydroxyphenyl)-1, 1, 1-trichloroethane (HPTE) inhibits FSH- and dibutyryl cAMP-stimulated steroidogenesis, and affects the mRNA levels of steroidogenic pathway enzymes in rat granulosa cells. However, HPTE showed a differential effect in FSH- and cAMP-stimulated cells in that HPTE more completely blocked FSH- when compared to cAMP-driven steroidogenesis. The objective of this study was to analyze the effects of HPTE on global gene expression profiles in untreated granulosa cells and those challenged with FSH or cAMP. Granulosa cells from immature rats were cultured with 0, 1, 5, or 10 M HPTE in the presence and absence of either 3 ng FSH/ml or 1 mM cAMP for 48 h. Total RNA was isolated for microarray analysis using the GeneChip Rat Genome 230 2.0 and ArrayAssist Microarray Suite. An investigation of changes in gene expression across all HPTE treatments showed that HPTE altered more genes in FSH- (~670 genes) than in cAMP-stimulated cells (~366 genes). Analysis confirmed that HPTE more effectively inhibited FSH- than cAMP-induced steroid pathway gene expression and steroidogenesis. Furthermore, expression patterns of novel genes regulating signal transduction, transport, cell cycle, adhesion, differentiation, motility and growth, apoptosis, development, and metabolism were all altered by HPTE. This study further established that HPTE exerts differential effects within the granulosa cell steroidogenic pathway, and revealed that these effects include broader changes in gene expression.

36

Harvey CN, Esmail M, Wang Q, Brooks AI, Zachow R, Uzumcu M