Hydrogen sulfide protects cardiomyocytes from doxorubicin-induced ferroptosis through the SLC7A11/GSH/GPx4 pathway by Keap1 S-sulfhydration and Nrf2 activation.

Recent studies have demonstrated that ferroptosis, a novel form of nonapoptotic regulated cell death plays an important role in doxorubicin (DOX)-induced cardiotoxicity (DoIC). Hydrogen sulfide (HS) is emerging as the third important gaseous mediator in cardiovascular system. However, whether HS has an effect on DOX-induced ferroptosis remains unknown. Here, we found that DOX not only triggered cardiomyocyte ferroptosis but also significantly inhibited the synthesis of endogenous HS in the murine model of chronic DoIC. Application of NaHS, an HS donor obviously activated the SLC7A11/GSH/GPx4 antioxidant pathway and thus alleviated DOX-induced ferroptosis and cardiac injury in mice. In contrast, cardiac-specific knockout of cystathionine γ-lyase gene (Cse) in mice (Cse/Cre) to abolish the cardiac synthesis of endogenous HS evidently exacerbated DOX-induced ferroptosis and cardiac dysfunction. A further suppression of SLC7A11/GSH/GPx4 pathway was obtained in Cse/Cre mice with DoIC, as compared to Cse/Cre mice with DoIC. The aggravation caused by cardiac-specific Cse deficiency was remarkably rescued by exogenous supplementation of NaHS. Moreover, in DOX-stimulated H9c2 cardiomyocytes, pretreatment with NaHS dose-dependently enhanced the activity of SLC7A11/GSH/GPx4 pathway and subsequently mitigated ferroptosis and mitochondrial impairment. On the contrary, transfection with Cse siRNA in DOX-stimulated H9c2 cardiomyocytes markedly inhibited SLC7A11/GSH/GPx4 pathway, thus leading to aggravated ferroptosis and more damage to mitochondrial structure and function. In addition, the protective effect of NaHS on DOX-induced ferroptosis was closely related to the S-sulfhydrated Keap1, which in turn promoted nuclear translocation of Nrf2 and the transcription of SLC7A11 and GPx4. In conclusion, our findings suggest that HS may exert protective effect on DoIC by inhibiting DOX-induced ferroptosis via Keap1/Nrf2-dependent SLC7A11/GSH/GPx4 antioxidant pathway.