The Function of PPARγ/AMPK/SIRT-1 Pathway in Inflammatory Response of Human Articular Chondrocytes Stimulated by Advanced Glycation End Products.

Accumulation of advanced glycation end products (AGEs) in the articular cartilage is a major risk factor for osteoarthritis (OA). To determine the mechanistic basis of AGE action in OA, we treated human articular chondrocytes with AGEs, and found that they not only up-regulated the pro-inflammatory cytokines interleukin (IL)-1β and tumor necrosis factor (TNF)-α, but also inhibited AMP-activated protein kinase (AMPK) phosphorylation and decreased sirtuin 1 (SIRT-1) levels in a concentration- and time-dependent manner. Pioglitazone, a peroxisome proliferator-activated receptor-γ (PPARγ) agonist restored the inhibited AMPK and SIRT-1 by AGEs. Pre-treatment of the cells with the agonists or antagonists of AMPK and SIRT-1 respectively abolished and augmented the inflammatory state induced by AGEs. Furthermore, AMPK agonist also restored the levels of SIRT-1 in the AGE-stimulated chondrocytes. Our findings indicate AGEs induce an inflammatory response in human articular chondrocytes via the PPARγ/AMPK/SIRT-1 pathway, which is therefore a potential target in OA therapy.