Sirtuin 3 (
SIRT3) is a potential therapeutic target for cardiovascular, metabolic, and other aging-related diseases. In this study, we investigated the role of
SIRT3 in
diabetic cardiomyopathy (DCM). Mice were injected with
streptozotocin (STZ, 60 mg/kg, ip) to induce
diabetes mellitus. Our proteomics analysis revealed that
SIRT3 expression in the myocardium of diabetic mice was lower than that of control mice, as subsequently confirmed by real-time PCR and Western blotting. To explore the role of
SIRT3 in DCM, SIRT3-knockout mice and 129S1/SvImJ wild-type mice were injected with STZ. We found that diabetic mice with
SIRT3 deficiency exhibited aggravated cardiac dysfunction, increased
lactate dehydrogenase (LDH) level in the serum, decreased
adenosine triphosphate (
ATP) level in the myocardium, exacerbated myocardial injury, and promoted myocardial
reactive oxygen species (ROS) accumulation. Neonatal rat cardiomyocytes were transfected with
SIRT3 siRNA, then exposed to high
glucose (HG, 25.5 mM). We found that downregulation of
SIRT3 further increased LDH release, decreased
ATP level, suppressed the mitochondrial membrane potential, and elevated oxidative stress in HG-treated cardiomyocytes.
SIRT3 deficiency further raised expression of necroptosis-related
proteins including receptor-interacting
protein kinase 1 (RIPK1), RIPK3, and cleaved
caspase 3, and upregulated the expression of
inflammation-related
proteins including NLR family pyrin domain-containing
protein 3 (NLRP3),
caspase 1 p20, and interleukin-1β both in vitro and in vivo. Collectively,
SIRT3 deficiency aggravated
hyperglycemia-induced mitochondrial damage, increased ROS accumulation, promoted necroptosis, possibly activated the NLRP3
inflammasome, and ultimately exacerbated DCM in the mice. These results suggest that
SIRT3 can be a molecular intervention target for the prevention and treatment of DCM.