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Introduction: Our previous studies have demonstrated advanced glycation end products (AGEs) was an important mediator in osteoarthritis (OA) which may induce mitochondrial dysfunction. AMP-activated protein kinase (AMPK), sirtuin 1 (SIRT1), and its downstream target peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) are the critical sensors that regulate mitochondrial biogenesis and have been recognized as therapeutic targets in OA. This study was designed to test whether AGEs caused mitochondrial dysfunction through modulation of AMPKα/SIRT1/PGC-1α. Methods: We knocked down or overexpressed AMPKα, SIRT1, and PGC-1α by small interfering RNA or plasmid DNA transfection, respectively. Mitochondrial membrane potential (△Ψ) was detected by tetraethylbenzimidazolyl carbocyanine iodide (JC-1) fluorescence probe. Results: The results showed that AGEs impaired △Ψ, intracellular ATP level, and mitochondrial DNA content, linked to decreased AMPKα, SIRT1, and PGC-1α expression in chondrocyte. AMPKα pharmacologic activation or overexpression of AMPKα, SIRT1, and PGC-1α reversed impairments of mitochondrial biogenesis, oxidative stress, and inflammation in AGEs-induced chondrocytes. However, AMPKα activation using AICAR had decreased capacity to increase each of those same effect readouts in AGEs-treated SIRT1-siRNA or PGC-1α-siRNA chondrocyte. Conclusion: Taken together, AGEs reduced the AMPKα/SIRT1/PGC-1α signaling in chondrocytes, leading to mitochondrial dysfunction as a result of increased oxidative stress, inflammation, and apoptosis. These results indicated that target AMPK may be as a novel therapeutic strategy for AGEs-related OA prevention. [ABSTRACT FROM AUTHOR]

Aims: The association between diabetes and neointimal expansion after vascular injury has been attributed to the accumulation of advanced glycation end products (AGEs). Here we investigated the inhibitory effect of cariporide, a specific Na+/H+ exchanger 1 blocker, on neointimal proliferation induced by AGEs in a balloon injury model. Methods: Expression of cyclooxygenase-2 (COX-2) and matrix metalloproteinase (MMP) was monitored by reverse transcription-polymerase chain reaction (RT-PCR) and real-time PCR. The level of reactive oxygen species (ROS) was determined by specific fluorescent probe. The phosphorylation of the nuclear factor-ĸB (NF-ĸB) system was studied by Western blot. Results: Cariporide significantly suppressed AGE-induced neointimal hyperplasia, vascular smooth muscle cell (VSMC) proliferation, COX-2, MMP-2 and MMP-9 expression. In addition, cariporide decreased AGE-induced ROS, malondiadehyde level and increased the superoxide dismutase and glutathione peroxidase activity. We also found that cariporide blocked AGE-induced NF-ĸB activation and inhibitor-ĸB degradation. Conclusions: The results indicated that cariporide inhibited AGE-induced neointimal formation by suppressing the VSMC proliferation and the up-regulation of COX-2, MMP-2, MMP-9 via inhibiting ROS and NF-ĸB activation. Copyright © 2013 S. Karger AG, Basel [ABSTRACT FROM AUTHOR]