Anhydrosafflor yellow B ameliorates oxeiptosis and FUNDC1-mediated mitophagy through activation of mTOR signaling pathway in cerebral ischemia/reperfusion injury

Anhydrosafflor yellow B (AHSYB) is an important water-soluble pigment in safflower, but its pharmacological research is quite sparse. In this study, we attempted to demonstrate the neuroprotective effect of AHSYB on oxeiptosis and FUNDC1-mediated mitophagy during cerebral ischemia/reperfusion injury (CI/RI) by establishing a classical middle cerebral artery occlusion/reperfusion (MCAO/R) rat model and an oxygen glucose deprivation/reperfusion (OGD/R) cellular model. The increase in apoptosis-inducing factor 1 (AIFM1) dephosphorylation level and the expression of autophagy marker, microtubule-associated proteins light chain 3 (LC3), confirmed the occurrence of oxeiptosis and mitophagy in ischemic stroke. AHSYB not only inhibited the expressions of kelch-like ECH-associated protein 1 (KEAP1) and phosphoglycerate mutase 5 (PGAM5), but also activated mammalian target of Rapamycin (mTOR) to repress the expressions of UNC-51-like kinase 1 (ULK1) and p- FUN14 domain containing 1 (FUNDC1) protein, and reversed CI/RI-induced mitochondrial structural abnormalities. Rapamycin, the mTOR inhibitor, obviously activated FUNDC1-mediated mitophagy and had a stimulative effect on the occurrence of oxeiptosis to some extent, which could be reversed by AHSYB. Our study suggested that AHSYB exhibited a noteworthy protective influence on MCAO/R rats and OGD/R-damaged SH-SY5Y cells, whose mechanism might be related to the inhibition of oxeiptosis and FUNDC1-mediated mitophagy. In addition, there seemed to be a certain relationship between the two modes of cell death, as inhibiting FUNDC1-mediated mitophagy with mTOR also appeared to ameliorate oxeiptosis. All these findings have implications for developing new therapeutic strategies for neurological diseases, providing important insights into the application of AHSYB in functional foods.