Heat stress releases arachidonic acid to induce autophagy in Sertoli cells by enhancing ROS-mitochondrial-endoplasmic reticulum stress axis

Abstract

As a key factor in determining testis size and sperm number, Sertoli cells (SCs) play a crucial role in male infertility. Under heat stress (HS), the reduction of SCs counts will negatively impact energy transport and supply to germ cells, leading to the spermatogenesis failure in humans and animals. However, how HS affects the number of SCs remains unclear. To address this, we hypothesized that the changes in SC metabolism could contribute to the adverse effects of HS. In this study, we first found that arachidonic acid (AA), an unsaturated fatty acid, was upregulated post HS exposure through LC-MS/MS metabolome detection. By measuring ROS and MDA levels, as well as expression levels of LC3, LAMP2 and P62, we showed that 100 µM of AA negatively affected the morphology of the testis and accelerated mitochondrial and endoplasmic reticulum damage in association with activating oxidative stress (OS). In line with this, we also observed an adverse effect of AA under HS on the accumulation of Ca2+, the increased expression of mitochondrial electron transport chain (ETC) proteins Complex I, II, V, as well as endoplasmic reticulum stress (ERS) unfolding proteins P-IRE1 and P-PERK. However, pretreatment with 5mM NAC (ROS inhibitor), 150 nM Rotenone (mitochondrial stress inhibitor), and 2.5 mM 4-PBA (ERS inhibitor) could reversed the autophagy induced by AA. Together, it is likely that AA modulates autophagy in SCs through ROS-mitochondrial-endoplasmic reticulum stress axis during HS, which may help to unravel the underlying mechanisms behind male infertility caused by high temperatures.