Advanced Glycation End Products Induced Mitochondrial Dysfunction of Chondrocytes through Repression of...

Area of Science:

• Biochemistry
• Cell Biology
• Molecular Medicine

Background:

• Advanced glycation end products (AGEs) are implicated in osteoarthritis (OA) pathogenesis, potentially inducing mitochondrial dysfunction.
• AMP-activated protein kinase (AMPK), sirtuin 1 (SIRT1), and peroxisome proliferator-activated receptor gamma coactivator-1α (PGC-1α) are key regulators of mitochondrial biogenesis and therapeutic targets in OA.

Purpose of the Study:

• To investigate whether AGEs induce mitochondrial dysfunction by modulating the AMPKα/SIRT1/PGC-1α signaling pathway in chondrocytes.
• To explore the therapeutic potential of targeting this pathway for OA prevention.

Main Methods:

• Chondrocytes were treated with AGEs, and gene expression of AMPKα, SIRT1, and PGC-1α was manipulated using siRNA or plasmid transfection.
• Mitochondrial membrane potential (ΔΨ) was assessed using JC-1 fluorescence, and intracellular ATP levels and mitochondrial DNA content were measured.

Main Results:

• AGEs impaired mitochondrial function, evidenced by reduced ΔΨ, ATP levels, and mitochondrial DNA content, correlating with decreased AMPKα, SIRT1, and PGC-1α expression.
• Pharmacologic activation or overexpression of AMPKα, SIRT1, and PGC-1α reversed AGEs-induced mitochondrial dysfunction, oxidative stress, and inflammation.
• AMPKα activation showed reduced efficacy in chondrocytes with suppressed SIRT1 or PGC-1α, highlighting the pathway's interdependence.

Conclusions:

• AGEs disrupt mitochondrial homeostasis in chondrocytes by downregulating the AMPKα/SIRT1/PGC-1α pathway, leading to increased oxidative stress, inflammation, and apoptosis.
• Targeting the AMPK pathway presents a promising therapeutic strategy for preventing and treating AGEs-related osteoarthritis.