GAPDH S-nitrosation contributes to age-related sarcopenia through mediating apoptosis

The age-related loss of muscle mass and muscle function known as sarcopenia is a major public health problem among older people. Recent research suggests that activation of apoptotic signaling is a critical aspect of the pathogenesis of age-related sarcopenia. However, little information exists in the literature about the apoptotic mechanism of sarcopenia in aging. Herein, we report that elevated glyceraldehyde-3-phosphate dehydrogenase (GAPDH) S-nitrosation and apoptosis occur in sarcopenia during natural aging and that translocation of S-nitrosated GAPDH to the nucleus and S-nitrosated GAPDH-mediated apoptosis contributed to sarcopenia. The levels and sites of GAPDH S-nitrosation in muscle tissues of young, adult and old mice were studied with a quantitative S-nitrosation proteomic analysis approach. GAPDH S-nitrosation increased with aging, and the GAPDH modification sites Cys¹⁵⁰, Cys¹⁵⁴ and Cys²⁴⁵ were identified. The upregulated S-nitrosation of GAPDH relies on inducible nitric oxide synthase (iNOS) rather than enzymes involved in denitrosylation. Treatment with the iNOS inhibitor 1400W or mutation of GAPDH S-nitrosation sites alleviated apoptosis of C2C12 cells, further demonstrating that GAPDH S-nitrosation in aging contributes to sarcopenia. Taken together, these findings reveal a new cellular mechanism underlying age-related sarcopenia, and the demonstration of muscle loss mediated by iNOS-induced GAPDH S-nitrosation suggests a potential therapeutic strategy for sarcopenia.