Transcriptome profiling of bovine ovarian theca interna during follicular atresia

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 515-547-Female Reproductive Endocrinology
Basic/Translational
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-526
Raymond J Rodgers*1, Nick Hatzirodos1, Katja Hummitzsch1 and Helen Irving-Rodgers2
1University of Adelaide, Adelaide, Australia, 2Griffith University, Gold Coast, Australia
During growth of ovarian follicles the theca interna develops adjacent to and on the stromal side of the follicular basal lamina and synthesizes androgen precursors for estradiol synthesis.  It is composed of steroidogenic cells, endothelial cells and fibroblasts and the steroidogenic cells are under the control of LH.  To learn more about how the theca interna behaves during follicular atresia we undertook transcriptome profiling during atresia, an important process for regulating ovulation rate and coordinating the timing of ovulation.  We investigated gene expression in the theca in small antral healthy follicles (n = 10) and antrally atretic follicles (n = 5) of 3-5 mm using Bovine Affymetrix Genome Arrays by ANOVA with Partek Genomics Suite software (v6.5).  A differentially regulated group (2 fold, False Discovery Rate P < 0.05) of 543 probe sets was uploaded into Ingenuity Pathway Analysis (IPA) and the following analyses conducted: gene networking, canonical pathway determination, cellular function and upstream regulator prediction.  This data set was also analysed in GOEAST (Gene Ontology Enrichment Analysis Toolkit) for significant association with GO terms under biological processes.  The results mainly show inhibition of cell replication and cycle by down regulation of genes such as MCM2, MCM4, MCM6, CDC6, CDC20 and CDCA8.  There was also transcriptional activation of the complement pathway and prostaglandin synthesis indicating stimulation of some inflammatory processes.  In addition to cell cycle regulators, predicted upstream regulators that were activated included p53 and those inhibited included TBX2 and E2F1 and growth factors VEGF, ERBB2 and HGF.  Surprisingly, apoptosis was not a major pathway or network.  We conclude that since there was a reduction in expression of genes associated with cell growth and proliferation and additionally, many genes associated with DNA/chromosome synthesis and repair, that during follicular atresia cell death in the theca interna is probably secondary to cell death in the membrana granulosa.

Nothing to Disclose: RJR, NH, KH, HI

*Please take note of The Endocrine Society's News Embargo Policy at http://www.endo-society.org/endo2013/media.cfm

Sources of Research Support: National Health and Medical Research Council of Australia