Probing soluble epoxide hydrolase expression and activity in painful osteoarthritis synovium and cel

We demonstrated higher levels of sEH protein in painful OA synovium, compared to non-painful controls, which will likely increase the catabolism of EETs in the knee joint in people with painful OA. Similarly, we report higher sEH activity in pm-OA and TKA-OA synovium, compared to non-OA controls, further supporting our hypothesis that sEH activity may play a key role in OA. Analysis of open access synovium single cell transcriptomic data identified the synovial subintimal and intimal fibroblasts as the highest sEH expressing cell type in OA synovium, and therefore likely to play an important role in the metabolism of EETs. Genetic association analysis of UK Biobank 450K WES data identified a novel genome-wide significant musculoskeletal pain associated variant of sEH K406R, chr8:27536830:A:G (GRCh38) and the most prevalent missense variant R287Q, chr8:27516348:G:A (rs751141), which we then confirmed to have functional activity in HEK293 cells. Designed catalytic mutations within the active site (D335N, Y466F, H524L) significantly reduced sEH activity but other mutants such as K406R, R103C and R287Q did not under our conditions.