Astaxanthin attenuates cigarette smoking-induced oxidative stress and inflammation in a sirtuin 1-dependent manner

Oxidative stress and chronic inflammation play key roles in the pathogenesis of chronic obstructive pulmonary disease (COPD). Astaxanthin (AXT) is a keto-carotenoid with a variety of biological functions, including antioxidant and anti-inflammatory effects This study aimed to explore the protective role and underlying mechanism of AXT in the pathogenesis of COPD. In this study, we found AXT alleviated pulmonary emphysema in a CS-exposed mouse model and regulated the expression of MMP-9/TIMP-1. And, AXT attenuates CSE-induced small airway fibrosis. Meanwhile, AXT inhibited Nrf2-modulated oxidative stress and the p65 NF-κB-regulated inflammatory pathway in both the mouse model and CSE-treated HBE cells. Mechanistically, AXT could directly bind to SIRT1 (the binding energy of the complex was -8.8 kcal/mol) and regulate the deacetylation activity of SIRT1. Finally, by activating SIRT1 deacetylation, AXT deacetylated Nrf2 and contributed to its action of reducing oxidative stress by generating antioxidant enzymes, and inhibiting p65 NF-κB transcriptional activity to suppress the inflammatory response. Our results show that treatment with AXT significantly reverses the oxidative stress and inflammation induced by cigarette smoke both in vivo and in vitro in a sirtuin 1-dependent manner.