Peroxynitrite-mediated SIRT (sirtuin)-1 inactivation contributes to nicotine-induced arterial stiffness in mice

Abstract

Objective: Inhibition of SIRT (sirtuin)-1, a nicotinamide adenine dinucleotide-dependent protein deacetylase, is linked to cigarette smoking-induced arterial stiffness, but the underlying mechanisms remain largely unknown. The aim of the present study was to determine the effects and mechanisms of nicotine, a major component of cigarette smoke, on SIRT1 activity and arterial stiffness. Approach and Results: Arterial stiffness, peroxynitrite (ONOO−) formation, SIRT1 expression and activity were monitored in mouse aortas of 8-week-old C57BL/6 mice (wild-type) or Sirt1-overexpressing (Sirt1Super) mice with or without nicotine for 4 weeks. In aortas of wild-type mice, nicotine reduced SIRT1 protein and activity by ≈50% without affecting its mRNA levels. In those from Sirt1Super mice, nicotine also markedly reduced SIRT1 protein and activity to the levels that were comparable to those in wild-type mice. Nicotine infusion significantly induced collagen I, fibronectin, and arterial stiffness in wild-type but not Sirt1Super mice. Nicotine increased the levels of iNOS (inducible nitric oxide synthase) and the co-staining of SIRT1 and 3-nitrotyrosine, a footprint of ONOO− in aortas. Tempol, which ablated ONOO− by scavenging superoxide anion, reduced the effects of nicotine on SIRT1 and collagen. Mutation of zinc-binding cysteine 395 or 398 in SIRT1 into serine (C395S) or (C398S) abolished SIRT1 activity. Furthermore, ONOO− dose-dependently inhibited the enzyme and increased zinc release in recombinant SIRT1. Finally, we found SIRT1 inactivation by ONOO− activated the YAP (Yes-associated protein) resulting in abnormal ECM (extracellular matrix) remodeling. Conclusions: Nicotine induces ONOO−, which selectively inhibits SIRT1 resulting in a YAP-mediated ECM remodeling. Visual Overview: An online visual overview is available for this article.