Expression and regulative function of tissue inhibitor of metalloproteinase 3 in the goat ovary and its role in cultured granulosa cells

Tissue inhibitor of metalloproteinase 3 (TIMP3) played a key role in female reproduction. However, its expression and function in goat are still unclear. In the present study, the full-length cDNA of goat TIMP3 was cloned from adult goat ovary; meanwhile, we demonstrated that putative TIMP3 protein shared a highly conserved amino acid sequence with known mammalian homologs. Real-time PCR results showed that TIMP3 was widely expressed in the tissues of adult goat. In the ovary, increasing expression of TIMP3 mRNA was discovered during the growth process of follicle and corpus luteum. Immunohistochemistry results suggested that TIMP3 protein existed in oocytes of all types of follicles, corpus luteum and granulosa and theca cells of primary, secondary, and antral but not primordial follicles. In vitro, human chorionic gonadotropin (hCG) stimulated the expression of TIMP3 in goat granulosa cells. hCG-induced TIMP3 mRNA expression was reduced by the inhibitors of protein kinase A, protein kinase C, MAPK kinase, or p38 kinase. Functionally, over-expression of TIMP3 significantly increased apoptosis and decreased the viability of cultured granulosa cells. Knockdown of TIMP3 could decrease hCG-induced progesterone secretion and the mRNA abundance of key steroidogenic enzymes (StAR, p450scc and HSD3B) as well as ECM proteins (DCN and FN). These findings provided evidence that the hCG induced expression of TIMP3 may play an important role in regulating goat granulosa cell survival and steroidogenesis.