Search

Deubiquitylases (DUBs) play a pivotal role in cell signalling and are often regulated by homo- or hetero-interactions within protein complexes. The BRCC36 isopeptidase complex (BRISC) regulates inflammatory signalling by selectively cleaving K63-linked polyubiquitin chains on Type I interferon receptors (IFNAR1). BRCC36 is a Zn 2+ -dependent JAMM/MPN DUB, a challenging ubiquitin protease class for the design of selective inhibitors. We identified first-in-class DUB inhibitors that act as BRISC molecular glues (BLUEs). BLUEs inhibit DUB activity by stabilising a BRISC dimer consisting of 16 subunits. The BLUE-stabilised BRISC dimer is an autoinhibited conformation, whereby the active sites and interactions with the recruiting subunit SHMT2 are blocked. This unique mode of action leads to highly selective inhibitors for BRISC over related complexes with the same catalytic subunit, splice variants and other JAMM/MPN DUBs. Structure-guided inhibitor resistant mutants confirm BLUEs on-target activity in cells, and BLUE treatment results in reduced interferon-stimulated gene (ISG) expression in human peripheral blood mononuclear cells from Scleroderma patients, a disease linked with aberrant IFNAR1 activation. BLUEs represent a new class of molecules with potential utility in Type I interferon-mediated diseases and a template for designing selective inhibitors of large protein complexes by promoting protein-protein interactions instead of blocking them., Competing Interests: Competing interests E.Z., R.G., J.M.S., and F.S. are named co-inventors in a provisional patent application to use BRISC inhibitors as potential therapeutics. J.M.S. owns equity in Alliance Discovery, Inc and the Barer Institute, Inc, and consults for Syndeavor Therapeutics, Inc.

Objective: Total hip replacement (THR) outcomes have been worse for patients with rheumatoid arthritis (RA) compared with those who have osteoarthritis (OA). Whether this remains true in contemporary patients with RA with a high use of disease-modifying and biologic therapy is unknown. The purpose of our study is to assess pain, function, and quality of life 2 years after primary THR, comparing patients with RA and patients with OA., Methods: Baseline and 2-year data were compared between validated patients with RA and patients with OA who were enrolled in a single-center THR registry between May 1, 2007, and February 25, 2011., Results: There were 5666 eligible primary THR identified, of which 193 were for RA. RA THR had worse baseline Western Ontario and McMaster Universities Osteoarthritis Index (WOMAC) pain (44.8 vs 53.2, p < 0.001) and function (38.7 vs 49.9, p < 0.001) compared with OA. These differences remained after surgery: pain (88.4 vs 94.0, p < 0.001) and function (82.9 vs 91.8, p < 0.001). Patients with RA were as likely to have a significant improvement as patients with OA (Δ WOMAC > 10) in pain (94% vs 96%, p = 0.35) and function (95% vs 94%, p = 0.69), but were 4 times as likely to have worse function (WOMAC ≤ 60; 19% vs 4%, p < 0.001) and pain (12% vs 3%, p < 0.001). In multivariate logistic regression controlling for multiple potential confounders, RA increased the odds of poor postoperative function (OR 4.32, 95% CI 1.57-11.9), and in patients without a previous primary THR, worse postoperative pain (OR 3.17, 95% CI 1.06-9.53)., Conclusion: Contemporary patients with RA have significant improvements in pain and function after THR, but higher proportions have worse 2-year pain and function. In addition, RA is an independent predictor of 2-year pain and poor function after THR, despite high use of disease-modifying therapy.