Integrated multi-omics and machine learning elucidate the pathogenic role of mitophagy in osteoarthritis and identify novel therapeutic strategies.

INTRODUCTION: Osteoarthritis (OA), the most prevalent degenerative joint disease, is characterized by chronic synovial inflammation, cartilage degradation, and disrupted cellular homeostasis. Impaired mitophagy has been implicated in OA pathogenesis, yet effective therapeutic strategies remain limited. This study aims to elucidate the role of mitophagy in OA and to identify cordycepin as a novel therapeutic agent that activates mitophagy, highlighting its potential clinical significance.

METHOD: Mitophagy alterations in clinical OA samples were assessed using immunohistochemistry and validated with public bulk transcriptomic data. Differences in mitophagy pathways were characterized, followed by machine learning to identify pivotal genes for a diagnostic nomogram. Single-cell gene set analysis and computational drug repositioning identified potential mitophagy-modulating therapeutics. In vitro, qPCR and Western blot measured inflammation and mitophagy markers, while autophagic flux dynamics were analyzed using JC-1 staining and tandem fluorescent LC3 (mRFP-GFP) transduction. In vivo efficacy and safety were evaluated in OA animal models.

RESULTS: We found significantly reduced mitophagy scores in OA synovium through integrated multi-omics approach. Machine learning identified seven pivotal mitophagy regulators: ULK1, ATG12, MAP1LC3B, UBB, UBC, TOMM40, and CSNK2B. Computational drug repositioning nominated cordycepin as a candidate therapeutic. In vitro, cordycepin demonstrated potent anti-inflammatory effects, attenuated cellular oxidative stress, inhibited mitochondrial outer membrane depolarization, and activated mitophagic flux. In vivo, cordycepin promoted LC3-TOMM20 co-localization, confirming mitophagy activation. This resulted in significant amelioration of synovitis and attenuation of cartilage degradation.

CONCLUSION: Our findings establish mitophagy impairment as a critical factor in OA pathogenesis and present cordycepin as a promising therapeutic option that targets mitochondrial quality control. This study lays the groundwork for future precision therapies aimed at degenerative joint disorders.