Loss of SIRT1 in diabetes accelerates DNA damage-induced vascular calcification

• Published in: Cardiovascular research Vol. 117; no. 3; pp. 836 - 849
• Main Authors: Bartoli-Leonard, Francesca, Wilkinson, Fiona L, Schiro, Andrew, Serracino Inglott, Ferdinand, Alexander, M Yvonne, Weston, Ria
• Format: Journal Article
• Language: English
• Published: England Oxford University Press 22.02.2021
• Subjects: Acid Anhydride Hydrolases - metabolism; Ataxia Telangiectasia Mutated Proteins - metabolism; Calcium Chloride - toxicity; Case-Control Studies; Cell Cycle Proteins - metabolism; Cells, Cultured; Cellular Senescence; Diabetes Mellitus - enzymology; Diabetes Mellitus - genetics; Diabetes Mellitus - pathology; Disease Progression; DNA Damage; DNA Repair; DNA-Binding Proteins - metabolism; Glucose - toxicity; Histones - metabolism; Humans; Hydrogen Peroxide - toxicity; MRE11 Homologue Protein - metabolism; Muscle, Smooth, Vascular - drug effects; Muscle, Smooth, Vascular - enzymology; Muscle, Smooth, Vascular - pathology; Myocytes, Smooth Muscle - drug effects; Myocytes, Smooth Muscle - enzymology; Myocytes, Smooth Muscle - pathology; Nuclear Proteins - metabolism; Original; Osteogenesis; Phenotype; Phosphorylation; Popliteal Artery - drug effects; Popliteal Artery - enzymology; Popliteal Artery - pathology; Signal Transduction; Sirtuin 1 - deficiency; Sirtuin 1 - genetics; Time Factors; Vascular Calcification - enzymology; Vascular Calcification - genetics; Vascular Calcification - pathology; Vascular calcification; Senescence; Diabetes; SIRT1; DNA damage
• ISSN: 0008-6363; 1755-3245
• DOI: 10.1093/cvr/cvaa134

Abstract Aims Vascular calcification is a recognized predictor of cardiovascular risk in the diabetic patient, with DNA damage and accelerated senescence linked to oxidative stress-associated pathological calcification. Having previously shown that systemic SIRT1 is reduced in diabetes, the aim was to establish whether SIRT1 is protective against a DNA damage-induced senescent and calcified phenotype in diabetic vascular smooth muscle cells (vSMCs). Methods and results Immunohistochemistry revealed decreased SIRT1 and increased DNA damage marker expression in diabetic calcified arteries compared to non-diabetic and non-calcified controls, strengthened by findings that vSMCs isolated from diabetic patients show elevated DNA damage and senescence, assessed by the Comet assay and telomere length. Hyperglycaemic conditions were used and induced DNA damage and enhanced senescence in vSMCs in vitro. Using H2O2 as a model of oxidative stress-induced DNA damage, pharmacological activation of SIRT1 reduced H2O2 DNA damage-induced calcification, prevented not only DNA damage, as shown by reduced comet tail length, but also decreased yH2AX foci formation, and attenuated calcification. While Ataxia Telanglectasia Mutated (ATM) expression was reduced following DNA damage, in contrast, SIRT1 activation significantly increased ATM expression, phosphorylating both MRE11 and NBS1, thus allowing formation of the MRN complex and increasing activation of the DNA repair pathway. Conclusion DNA damage-induced calcification is accelerated within a diabetic environment and can be attenuated in vitro by SIRT1 activation. This occurs through enhancement of the MRN repair complex within vSMCs and has therapeutic potential within the diabetic patient.