Mitochondrial Dysfunction in Osteoarthritis Pathogenesis

Osteoarthritis is the most prevalent joint disorder worldwide, characterised by progressive cartilage loss, pain and impaired mobility. Central to its pathogenesis is the failure of chondrocytes—the specialised cells that maintain cartilage—to preserve mitochondrial health. Mitochondria underlie cellular energy production via oxidative phosphorylation and regulate redox balance, calcium homeostasis and programmed cell death. In osteoarthritic cartilage, mitochondrial DNA damage, defective respiratory chain activity and excessive generation of reactive oxygen species disrupt organelle dynamics and bioenergetic output. Impaired fusion–fission balance and defective mitophagy allow accumulation of dysfunctional mitochondria, amplifying oxidative stress and triggering chondrocyte apoptosis, senescence and matrix degradation through activation of catabolic enzymes. Ageing, mechanical overload and low-grade inflammation exacerbate these derangements. Emerging insights into key mediators such as SIRT3, SOD2 and HIF-1α reveal potential for mitochondrial-targeted therapies to modify disease progression and restore joint homeostasis.

Research from Nature Portfolio

Recent studies have demonstrated that mechanical overloading of cartilage precipitates an imbalance in mitochondrial superoxide production, causing downregulation of the mitochondrial antioxidant enzyme SOD2 in chondrocytes. This redox disturbance drives cartilage degeneration in animal models. Restoration of SOD2 expression or administration of cell-permeable antioxidants suppresses superoxide accumulation, preserves mitochondrial function and mitigates cartilage damage, highlighting redox homeostasis as a viable therapeutic target in osteoarthritis.

Mitochondrial Dysfunction in Osteoarthritis Pathogenesis publication trend

The graph below shows the total number of articles in mitochondrial dysfunction in osteoarthritis pathogenesis across all publications each year (not limited to Nature Index journals).

Technical terms

Mitochondria: Organelles that generate adenosine triphosphate through oxidative phosphorylation and regulate cellular redox and apoptosis.

Reactive oxygen species (ROS): Chemically reactive oxygen-containing molecules that can damage proteins, lipids and DNA when in excess.

Mitophagy: Selective removal of damaged mitochondria via the autophagy pathway to maintain organelle quality control.

Oxidative phosphorylation (OXPHOS): Mitochondrial process by which electrons are transferred through the respiratory chain to synthesise ATP.

Superoxide dismutase 2 (SOD2): Mitochondrial enzyme that converts superoxide radicals into less harmful molecules.

Chondrocytes: Specialized cells within cartilage responsible for producing and maintaining the extracellular matrix.

SIRT3: Mitochondrial deacetylase that modulates protein acetylation state and preserves respiratory chain function.

References

1. Mitochondrial transfer balances cell redox, energy and metabolic homeostasis in the osteoarthritic chondrocyte preserving cartilage integrity. Theranostics (2024).
2. Reprogramming of Mitochondrial Respiratory Chain Complex by Targeting SIRT3‐COX4I2 Axis Attenuates Osteoarthritis Progression. Advanced Science (2023).
3. Stabilization of HIF-1α alleviates osteoarthritis via enhancing mitophagy. Cell Death & Disease (2020).
4. Mechanical overloading causes mitochondrial superoxide and SOD2 imbalance in chondrocytes resulting in cartilage degeneration. Scientific Reports (2015).
5. Irisin Mitigates Oxidative Stress, Chondrocyte Dysfunction and Osteoarthritis Development through Regulating Mitochondrial Integrity and Autophagy. Antioxidants (2020).
6. Mitochondria: Potential Targets for Osteoarthritis. Frontiers in Medicine (2020).