BACKGROUND: Osteoarthritis (OA), characterized by chondrocyte senescence and oxidative stress, affects over 300 million people globally. Kisspeptin-54, a neuropeptide with pleiotropic protective effects, was investigated for its role in chondrocyte senescence and its underlying mechanisms.
METHODS: Oxidative stress and senescence were induced in primary mouse chondrocytes by treating them with TBHP. Kisspeptin-54 was administered at varying concentrations (10-1000 nM) to assess cytoprotection, while SIRT3 was knocked down using adenoviral shRNA to validate mechanistic pathways. Telomere length, mTERT expression, telomerase activity, and p53 acetylation were evaluated via Southern blot, RT-PCR, and western blot techniques. Furthermore, senescence was evaluated through the application of SA-β-galactosidase staining alongside the measurement of PAI-1 expression.
RESULTS: TBHP induced dose-dependent GPR54 downregulation, oxidative stress (260 % increase in ROS), telomere attrition (41 % reduction in length), and senescence (270 % increase in SA-β-galactosidase-positive cells). Kisspeptin-54 (≤200 nM) rescued cell viability, reduced LDH release (57 % at 200 nM), and mitigated ROS and SOD activity decline. Mechanistically, Kisspeptin-54 restored SIRT3 expression, suppressed p53 acetylation (Acetyl-p53[K382] reduced by 56 % at 200 nM), and preserved telomere function (telomere length restored to 91 % of control). SIRT3 knockdown abrogated these effects, confirming its critical role.
CONCLUSION: Kisspeptin-54 alleviates chondrocyte senescence via a dual mechanism: (1) SIRT3-mediated restoration of mitochondrial antioxidant capacity and telomere homeostasis; (2) inhibition of p53 hyperacetylation and downstream senescence signaling. These findings establish Kisspeptin-54 as an innovative therapeutic candidate for OA acting through the modulation of the SIRT3/p53 axis to combat oxidative stress and telomere dysfunction.
