The New Role of Sirtuin1 in Human Osteoarthritis Chondrocytes by Regulating Autophagy

ObjectiveThe aim of this study is to investigate the role of Sirtuin1 (Sirt1) in the regulation of autophagy for human osteoarthritis (OA) chondrocytes.DesignAll cartilage samples were collected from human donors, including young group, aged group, and OA group. Primary chondrocytes were isolated and cultured with Sirt1 activator or inhibitor. Sirt1 expression in cartilage tissue and chondrocytes was evaluated, and the deacetylation activity of Sirt1 was determined. The alteration of autophagy activity after upregulating or downregulating Sirt1 was detected. Chondrocytes were treated with autophagy activator and inhibitor, and then the protein level of Sirt1 was examined. The interactions between Sirt1 and autophagy-related proteins Atg7, microtubule associated protein 1 light chain 3 (LC3), and Beclin-1 were determined by using immunoprecipitation.ResultsThe assay of articular cartilage revealed that the expression of Sirt1 might be age-related: highly expressed in of younger people, and respectively dec...