Role of poly(ADP-ribose) polymerases in male reproduction

Poly(ADP-ribose) polymerases (PARPs) are a family of enzymes involved in a wide variety of biological processes, including DNA repair and maintenance of genomic stability following genotoxic stress, and regulates the expression of various proteins at the transcriptional level as well as replication and differentiation. However, excessive activation of PARP has been shown to contribute to the pathogenesis of several diseases associated with oxidative stress (OS), which has been known to play a fundamental role in the etiology of male infertility. Based on the degree and type of the stress stimulus, PARP directs cells to specific fates (such as, DNA repair vs. cell death). A large volume of accumulated evidence indicates the presence of PARP and its homologs in testicular germ line cells and its activity may offer a key mechanism for keeping DNA integrity in spermatogenesis. On the other hand, a possible role of PARP overactivation in OS-induced male reproductive disorders and in human sperm is gaining significance in recent years. In this review, we focus on the findings about the importance of PARP-1 and PARP-2 in male reproduction and possible involvement of PARP overactivation in various clinical conditions associated with male infertility.