Oxidative stress induces ferroptosis in tendon stem cells by regulating mitophagy through cGAS-STING pathway.

Tendinopathy is one of the most prevalent sports injury diseases in orthopedics. However, there is no effective treatment or medicine. Recently, the discovery of tendon stem cells (TSCs) provides a new perspective to find new therapeutic methods for Tendinopathy. Studies have shown that oxidative stress will inevitably cause TSCs injury during tendinopathy, but the mechanism has not been fully elucidated. Here, we report the oxidative damage of TSCs induced by HO via ferroptosis, as well, treatment with HO raised the proportion of mitochondria engulfed by autophagosomes in TSCs. The suppression of mitophagy by Mdivi-1 significantly attenuates the HO-induced ferroptosis in TSCs. Mechanically, HO actives the cGAS-STING pathway, which can regulate the level of mitophagy. Interfering with cGAS could impair mitophagy and the classical ferroptotic events. In the rat model of tendinopathy, interference of cGAS could relieve tendon injury by inhibiting ferroptosis. Overall, these results provided novel implications to reveal the molecular mechanism of tendinopathy, by which pointed to cGAS as a potential therapeutic target for the treatment of tendinopathy.