Gene Bionetwork Analysis of Ovarian Primordial Follicle Development

Ovarian primordial follicles are critical for female reproduction and comprise a finite pool of gametes arrested in development. A systems biology approach was used to identify regulatory gene networks essential for primordial follicle development. Transcriptional responses to eight different growth factors known to influence primordial follicles were used to construct a bionetwork of regulatory genes involved in primordial follicle development. Over 1500 genes were found to be regulated by the various growth factors and a network analysis identified critical gene modules involved in a number of signaling pathways and cellular processes. A set of 55 genes was identified as potential critical regulators of these gene modules, and a subnetwork associated with development was determined. Within the network two previously identified regulatory genes were confirmed (i.e. Pdgfa and Fgfr2) and a new factor was identified, connective tissue growth factor (CTGF). CTGF was tested in ovarian organ cultures and found to stimulate primordial follicle development. Therefore, the relevant gene network associated with primordial follicle development was validated and the critical genes and pathways involved in this process were identified. This is one of the first applications of network analysis to a normal developmental process. These observations provide insights into potential therapeutic targets for preventing ovarian disease and promoting female reproduction. For GSM509254-9: We used microarrays to determine genes expressed differentially between control and CTGF (connective tissue growth factor) treated P4 ovary. For GSM510028-65: We used microarrays to determine genes expressed differentially between control and growth factors treated P4 ovary and co-expressed in the same manner for P4 ovaries treated with 8 growth factors AMH, BMP4, GDNF, FGF2, FGF7, KITLG, LIF, PDGFab. For GSM509254-9: RNA samples from 3 control groups are compared to 3 CTGF treated ovary groups. For GSM510028-65: RNA samples from 14 control samples are compared to 3 growth factor treated ovary samples for each AMH, BMP4, GDNF, FGF2, FGF7, KITLG, LIF, PDGFab treatment.