Reprogramming of Mitochondrial Respiratory Chain Complex by Targeting SIRT3-COX4I2 Axis Attenuates Osteoarthritis...

Area of Science:

• Mitochondrial biology
• Osteoarthritis pathogenesis
• Epigenetics

Background:

• Mitochondrial homeostasis is crucial for cartilage integrity and implicated in osteoarthritis (OA) development.
• The precise mechanisms linking mitochondrial function to OA progression remain unclear.
• Silent mating type information regulation 2 homolog 3 (SIRT3) is a key mitochondrial deacetylase.

Purpose of the Study:

• To investigate the role of mitochondrial deacetylation in OA.
• To elucidate the mechanistic relationship between SIRT3 and OA development.
• To explore SIRT3 as a potential therapeutic target for OA.

Main Methods:

• Correlative analysis of SIRT3 expression in human OA cartilage and mouse models.
• Assessment of OA phenotypes in global SIRT3-deleted mice.
• Mechanistic studies involving SIRT3 targeting and deacetylation of COX4I2.
• Evaluation of honokiol's effect on SIRT3 activation and OA protection in mice.

Main Results:

• SIRT3 expression negatively correlates with OA severity in human and mouse samples.
• SIRT3 deletion exacerbates OA phenotypes, including matrix degradation and inflammation.
• SIRT3 deacetylates COX4I2, preserving mitochondrial homeostasis and respiratory function.
• Honokiol treatment activates SIRT3, ameliorates OA, and restores metabolic equilibrium.

Conclusions:

• Loss of mitochondrial SIRT3 is critical for OA development.
• SIRT3-mediated deacetylation of COX4I2 rescues mitochondrial function and improves OA.
• Inducing SIRT3 represents a promising therapeutic strategy for OA treatment.