Simeprevir Improves Osteoarthritis Cartilage Degeneration and Inflammation by Targeting PRPS2 to Inhibit Purine Metabolism and NF-κB Signaling Pathway

Background The progression of osteoarthritis (OA) is increasingly recognized as being driven by metabolic-inflammatory crosstalk. Phosphoribosyl pyrophosphate synthetase 2 (PRPS2), a crucial rate-limiting enzyme in purine synthesis, exhibits unique pathogenic potential in cellular metabolic reprogramming. This study aimed to elucidate the specific pathological role of PRPS2 in OA and explore the repurposing of FDA-approved drugs as novel disease-modifying osteoarthritis drugs (DMOADs). Methods Bioinformatic analysis of OA synovial transcriptomes (GSE117999) and xCell immune deconvolution were integrated to evaluate PRPS2 expression and immune infiltration. Structure-based virtual screening and 80-ns molecular dynamics (MD) simulations were employed to identify PRPS2 inhibitors. The therapeutic efficacy and target specificity were thoroughly validated in an in vitro OA model (IL-1β-stimulated SW1353 chondrocytes) using RT-qPCR, Western blotting, cellular thermal shift assay (CETSA), and siRNA-mediated gene silencing. Results PRPS2 was significantly upregulated in OA tissues and positively correlated with the infiltration of pro-inflammatory adaptive immune cells. Virtual screening identified the antiviral drug Simeprevir as a candidate PRPS2 binder, establishing a stable interaction network within its catalytic pocket (MM-GBSA ΔG = -32.42 kcal/mol). In vitro validation confirmed that Simeprevir physically binds PRPS2, inhibits its enzymatic activity, and reduces downstream uric acid accumulation. This metabolic correction effectively blocked the NF-κB inflammatory cascade, significantly reducing pro-inflammatory mediators (PGE2, IL-6, TNF-α) and restoring extracellular matrix homeostasis. Notably, PRPS2 knockdown abolished these protective effects, confirming target specificity. Conclusions PRPS2 upregulation may contribute to the metabolic-inflammatory axis in OA. Simeprevir inhibits PRPS2 activity and attenuates OA-related inflammatory and catabolic responses in vitro, suggesting its potential as a candidate DMOAD warranting further preclinical investigation.