ACTRT2 deficiency increases spermatogonia vulnerability to ferroptosis.

The death of spermatogonia leads to decreased spermatogenesis and male infertility. Indeed, spermatogonia are vulnerable to various external damage factors and would be caused to cell death. However, the mechanism is still unclear. In this study, we found that the actin-related protein T2 (ACTRT2) was specifically expressed in testicular tissue and was associated with spermatogenesis. In vitro, when the cells were treated with busulfan, the proportion of spermatogonial cell line (GC-1) death in the low-ACTRT2 group increased significantly. Reactive oxygen species (ROS) accumulation and typical mitochondrial changes associated with ferroptosis occurred. In vivo, the seminiferous tubules in ACTRT2-/- mice were significantly shrunken. In addition, after being treated with busulfan, spermatogenesis in ACTRT2+/- mice decreased significantly compared to that in wild-type mice. In ACTRT2+/- testes, the expression levels of acyl-CoA synthetase long-chain family member 4 (ACSL4) and Arachidonic acid 15-lipoxygenase-1 (ALOX15) were upregulated, while the expression levels of Solute carrier family 7 member 11 (SLC7A11) and Glutathione peroxidase 4 (GPX4) were downregulated. Finally, we found that the expression of Solute carrier family 11 member 2 (SLC11A2), Iron responsive element binding protein 2 (IREB2), and Transferrin receptor protein 1 (TFRC) increased significantly in the low-ACTRT2 group, which transports iron into the cell to increase the intracellular unstable iron pool. In conclusion, ACTRT2 deficiency leads to intracellular iron overload and damage to mitochondria, ultimately increasing spermatogonia vulnerability to ferroptosis.