HSP72 alleviates heat stress-induced oxidative damage in boar Sertoli cells through modulating the AGE-RAGE/NOX4/NF-κB axis.

Heat stress is widely recognized to exert detrimental effects on boar semen quality. This occurs primarily through oxidative stress, which perturbs spermatogenesis by damaging the structural integrity and functional capacity of the involved cells. Heat shock protein 72 (HSP72) plays crucial roles in maintaining redox balance against oxidative stress. A clearer understanding of the functional roles and mechanistic actions of HSP72 in boar Sertoli cells under heat stress, however, requires more definitive evidence. Herein, we mainly investigated the regulatory and functional roles of HSP72 in alleviating heat stress-induced oxidative damage of boar Sertoli cells. The results indicated that heat stress enhanced ROS and MDA accumulation, and decreased the activity of enzymatic antioxidants, which further caused damage of the secretory function and blood-testis barrier structure of boar Sertoli cells. Results from transcriptome and metabolic analysis explored that heat stress activated the AGE-RAGE signaling axis and further elevated the expression of its downstream molecules, including RAGE, NOX4, and NF-κB proteins. Mechanistically, RAGE gene deficiency abolished the adverse effects of heat stress on boar Sertoli cells, and NF-κB signaling also mediated heat stress-induced oxidative stress. HSP72 translocated from the cytoplasm to the nucleus of boar Sertoli cells under heat stress, and further offset heat stress-induced oxidative stress. Moreover, HSP72 attenuated heat stress-induced AGE accumulation and higher expressions of NOX4 and NF-κB proteins. Collectively, HSP72 alleviated heat stress-induced oxidative damage in boar Sertoli cells through repressing the activity of AGE-RAGE/NOX4/NF-κB axis. Our findings uncovered a novel signaling axis involved heat stress-induced oxidative damage in Sertoli cells, and provided stronger evidence for HSP72's critical roles in maintaining the functional roles and structural integrity of boar Sertoli cells in heat stress. This study provided potential strategies to enhance heat stress resistance of boar semen quality.