The impact of mitochondrial dysfunction on osteoarthritis cartilage: current insights and emerging mitochondria-targeted therapies.

Osteoarthritis (OA) is a degenerative joint disease associated with age, prominently marked by articular cartilage degradation. In OA cartilage, the pathological manifestations show elevated chondrocyte hypertrophy and apoptosis. The mitochondrion serves as key energy supporter in eukaryotic cells and is tightly linked to a myriad of diseases including OA. As age advances, mitochondrial function declines progressively, which leads to an imbalance in chondrocyte energy homeostasis, partially initiating the process of cartilage degeneration. Elevated oxidative stress, impaired mitophagy and mitochondrial dynamics jointly contribute to chondrocyte pathology, with mitochondrial DNA haplogroups, particularly haplogroup J, influencing OA progression. Therapeutic approaches directed at mitochondria have demonstrated remarkable efficacy in treating various diseases, with triphenylphosphonium (TPP) emerging as the most widely utilized molecule. Other strategies encompass Dequalinium (DQA), the Szeto-Schiller (SS) tetrapeptide family, the KLA peptide, and mitochondrial-penetrating peptides (MPP), etc. These molecules share common properties of lipophilicity and positive charge. Through various technological modifications, they are conjugated to nanocarriers, enabling targeted drug delivery to mitochondria. Therapeutic interventions targeting mitochondria offer a hopeful direction for OA treatment. In the future, mitochondria-targeted therapy is anticipated to improve the well-being of life for the majority of OA patients. This review summarizes the link between chondrocyte mitochondrial dysfunction and OA, as well as discusses promising mitochondria-targeted therapies and potential therapeutic compounds.