Adenosine and guanosine-based oligonucleotides-loaded PLGA nanoparticles attenuates progression of surgically induced osteoarthritis.

Osteoarthritis (OA) is a chronic degenerative joint disease that lacks effective therapies to halt its progression. While endogenous purinergic signaling-particularly via adenosine-shows promise for reducing inflammation, it is limited by short half-life and off-target effects. To address these limitations, we developed an optimal anti-inflammatory adenosine-guanosine-based oligonucleotide encapsulated in poly(lactic-co-glycolic) acid (PLGA)-based nanoparticles (NanoOligo) to enhance in vivo stability and investigated its impact on surgically induced OA models and the underlying mechanisms responsible for its anabolic effects. A large oligonucleotide library (482 unique 10- to 20-mer sequences) was screened in RAW264.7 macrophages under LPS-induced inflammation to identify the most potent candidate, which was then encapsulated into PLGA nanoparticles using a microfluidic system. NanoOligo significantly protected against cartilage degeneration and alleviated pain behaviors in the rat ACLT + pMx model following intra-articular administration. In IL-1β-treated chondrocytes, it markedly suppressed inflammatory cytokines (TNFα, IL-6) and catabolic proteases (MMP-3, MMP-13, ADAMTS5). Mechanistically, NanoOligo's anti-catabolic effects were dependent on A1R and A2AR, leading to activation of the PKA-CREB axis and suppression of p38 MAPK signaling, which in turn reduced oxidative stress and cellular senescence via upregulation of the Sirt1-Nrf2-HO-1 antioxidant pathway. Collectively, these findings support joint-localized purinergic modulation as a potential therapeutic target for OA treatment, aligning structural protection with improvements in pain-related behaviors.