Comprehensive characterisation of poly(ADPribosyl)ation in spermatozoa as a novel and early biomarker of sperm health. A preliminary look

Poly(ADPribose) polymerases (PARPs) are a family of enzymes involved in various biological processes, including DNA repair, maintaining genomic stability, chromatin compaction and cell death induction. PARP activation has been associated with oxidative stress (OS), which causes oxidative DNA damage and negatively affects sperm quality and function. OS plays a fundamental role in the aetiology of male infertility. As nuclear poly(ADPribose) polymerases (PARPs) are markers of DNA damage and their homologues have been found in testicular germ cells, this preliminary study examined the poly(ADPribosyl)ation system in the sperm of men living in the Sele River Valley (an area with low environmental exposure) and in the Land of Fires (an area sadly renowned for its high pollution levels). Additionally, the poly(ADPribosyl)ation of sperm nuclear basic proteins (SNBPs) was investigated for the first time, given that these proteins play a key role in the compaction of sperm chromatin. Our results revealed the presence of a complete and active poly(ADPribosyl)ation system and showed that PARP automodification is linked to the extent of sperm DNA damage. We have also demonstrated the endogenous SNBP heteromodification, which is associated with chromatin decondensation. Finally, we propose a molecular mechanism linking PARP automodification and DNA damage with SNBP heteromodification and the state of DNA compaction.