Aberrant subchondral osteoblastic metabolism modifies Na(V)1.8 for osteoarthritis

Pain is the most prominent symptom of osteoarthritis (OA) progression. However, the relationship between pain and OA progression remains largely unknown. Here we report osteoblast secret prostaglandin E2 (PGE2) during aberrant subchondral bone remodeling induces pain and OA progression in mice. Specific deletion of the major PGE2 producing enzyme cyclooxygenase 2 (COX2) in osteoblasts or PGE2 receptor EP4 in peripheral nerve markedly ameliorates OA symptoms. Mechanistically, PGE2 sensitizes dorsal root ganglia (DRG) neurons by modifying the voltage-gated sodium channel Na(V)1.8, evidenced by that genetically or pharmacologically inhibiting Na(V)1.8 in DRG neurons can substantially attenuate OA. Moreover, drugs targeting aberrant subchondral bone remodeling also attenuates OA through rebalancing PGE2 production and Na(V)1.8 modification. Thus, aberrant subchondral remodeling induced Na(V)1.8 neuronal modification is an important player in OA and is a potential therapeutic target in multiple skeletal degenerative diseases.