Ameliorative Effect of Itaconic Acid/IRG1 Against Endoplasmic Reticulum Stress-Induced Necroptosis in Granulosa Cells via PERK-ATF4-AChE Pathway in Bovine

The necroptosis of granulosa cells has been proven to be one of the important triggers of follicular atresia, which is an important cause of reduced reproductive capacity in cows. The rapid growth of granulosa cells is accompanied by endoplasmic reticulum stress (ERS), leading to granulosa cell death. However, the link between ERS and necroptosis, as well as its mechanism in bovine granulosa cells is still unclear. Itaconic acid is an endogenous anti-inflammatory and antioxidant small-molecule compound that can alleviate ERS. Therefore, the aim of the current study is to evaluate the effect of ERS on necroptosis and investigate the ameliorative effect of itaconic acid against ERS-induced necroptosis in granulosa cells. Bovine granulosa cells were treated with tunicamycin (Tm) to induce ERS. After the addition of the necroptosis inhibitor Nec-1 and the detection of the necroptosis inducer acetylcholinesterase (AChE), flow cytometry, transmission electron microscopy, and mass spectrometry were used to analyze the expression of itaconic acid and IRG1 in the granulosa cells. In addition, the role of the PERK pathway downstream of ERS in ERS-induced necroptosis was also investigated. We report here that ERS can induce necroptosis in granulosa cells. Itaconic acid supplementation significantly attenuates the effect of ERS-induced damage. In summary, this research provides a scientific basis and a drug reference for treating follicular atresia and improving bovine reproductive capacity.