SIRT3 deficiency delays diabetic skin wound healing via oxidative stress and necroptosis enhancement

Sirtuin 3 (SIRT3) plays a vital role in several dermatological diseases. However, the role and detailed mechanism of SIRT3 in diabetic wound healing are unknown well yet. To explore possible involvement of SIRT3 and necroptosis in diabetic skin wound healing, SIRT3 knockout (KO) mice and 129S1/SvImJ wild-type (WT) mice were injected with streptozotocin (STZ), and mice skin fibroblasts were exposed to high glucose (HG). It was found that SIRT3 expression decreased in the skin of diabetic patients. SIRT3 deficiency delayed healing rate, reduced blood supply and vascular endothelial growth factor expression, promoted superoxide production, increased malondialdehyde (MDA) levels, decreased total antioxidant capacity (T-AOC), reduced superoxide dismutase (SOD) activity and aggravated ultrastructure disorder in skin wound of diabetic mice. SIRT3 deficiency inhibited mice skin fibroblasts migration with HG stimulation, which was restored by SIRT3 overexpression. SIRT3 deficiency also suppressed alpha-smooth muscle actin (alpha-SMA) expression, enhanced superoxide production but decreased mitochondrial membrane potential with HG stimulation after scratch. SIRT3 deficiency further elevated receptor-interacting protein kinase 3 (RIPK3), RIPK1 and caspase 3 expression both in vitro and in vivo. Collectively, SIRT3 deficiency delayed skin wound healing in diabetes, the mechanism might be related to impaired mitochondria function, enhanced oxidative stress and increased necroptosis. This may provide a novel therapeutic target to accelerate diabetic skin wound healing.