Deubiquitinases In Ubiquitin Homeostasis And Disease

Protein quality control (PQC) is indispensable for normal cellular functions, ensuring proteins are properly folded and removing those proteins that are functioning aberrantly. Perturbations in PQC can lead to various malignancies, neurodegeneration and neurological diseases. The Ubiquitin-Proteasome Pathway (UPP) is one important pathway in PQC, it relies on ubiquitination-dependent post-translational modification to selectively degrade misfolded or short-lived protein. Ubiquitination is reversed by the action of proteases known as deubiquitinating enzymes (DUBs). By hydrolyzing ubiquitin linkages, DUBs are responsible for cleaving and activating newly produced ubiquitin molecules, editing poly-Ub chains, removing ubiquitin from a substrate protein and recycling mono-Ub. Here, I investigated two proteins critically involved in the UPP: one that is important for normal cellular function (USP5), and another whose mutations cause neurodegeneration (ataxin-3). Ubiquitin Specific Protease 5 (USP5) is a member of the USP class of DUBs. Based on structural and in vitro results, it was long thought to function as a recycler of mono-Ub in the cell, by hydrolyzing unanchored poly-Ub chains. We studied the function of USP5 in vivo in Drosophila melanogaster. Knockdown of DmUSP5 in the whole fly results in death during developmental stages and in an increase in poly-Ub chains, but does not result in a depletion of mono-Ub in the fly, contrary to long-held opinion. Based on our data, lethality from USP5 knockdown is not due to depletion of mono-Ub, but likely resulted due to accumulation of unanchored poly-Ub chains and disruption of proteasomal degradation. Our results also suggest that USP5 has specific substrates. The other DUB investigated, ataxin-3, is the disease causing protein in the age-related, poly-glutamine (polyQ) dependent disease Spinocerebellar Ataxia Type-3 (SCA3). Through its different interacting partners, ataxin-3 is involved in protein quality control pathways. One such protein is the AAA ATPase Valosin Containing Protein (VCP). Ataxin-3 interacts directly with VCP through a VCP Binding Motif (VBM). Through biochemistry, Drosophila genetics and physiological assays, we showed that pathogenic ataxin-3 with a mutated VBM is markedly less toxic than its intact pathogenic counterpart. Mutating the VBM of ataxin-3 caused a delay in the aggregation of ataxin-3 in vivo, in various tissues tested. We propose that VCP acts as a nucleation center to increase local concentrations of ataxin-3 proteins and increase their likelihood of interacting and fibrilization. Our work suggest this interaction as a potential therapeutic target for SCA3

2022 update

Funding Information: This study was funded by European League Against Rheumatism. Publisher Copyright: © Author(s) (or their employer(s)) 2022. No commercial re-use. See rights and permissions. Published by BMJ.Objectives: To provide an update of the EULAR rheumatoid arthritis (RA) management recommendations addressing the most recent developments in the field. Methods: An international task force was formed and solicited three systematic literature research activities on safety and efficacy of disease-modifying antirheumatic drugs (DMARDs) and glucocorticoids (GCs). The new evidence was discussed in light of the last update from 2019. A predefined voting process was applied to each overarching principle and recommendation. Levels of evidence and strengths of recommendation were assigned to and participants finally voted on the level of agreement with each item. Results: The task force agreed on 5 overarching principles and 11 recommendations concerning use of conventional synthetic (cs) DMARDs (methotrexate (MTX), leflunomide, sulfasalazine); GCs; biological (b) DMARDs (tumour necrosis factor inhibitors (adalimumab, certolizumab pegol, etanercept, golimumab, infliximab including biosimilars), abatacept, rituximab, tocilizumab, sarilumab and targeted synthetic (ts) DMARDs, namely the Janus kinase inhibitors tofacitinib, baricitinib, filgotinib, upadacitinib. Guidance on monotherapy, combination therapy, treatment strategies (treat-to-target) and tapering in sustained clinical remission is provided. Safety aspects, including risk of major cardiovascular events (MACEs) and malignancies, costs and sequencing of b/tsDMARDs were all considered. Initially, MTX plus GCs is recommended and on insufficient response to this therapy within 3-6 months, treatment should be based on stratification according to risk factors; With poor prognostic factors (presence of autoantibodies, high disease activity, early erosions or failure of two csDMARDs), any bDMARD should be added to the csDMARD; after careful consideration of risks of MACEs, malignancies and/or thromboembolic events tsDMARDs may also be considered in this phase. If the first bDMARD (or tsDMARD) fails, any other bDMARD (from another or the same class) or tsDMARD (considering risks) is recommended. With sustained remission, DMARDs may be tapered but should not be stopped. Levels of evidence and levels of agreement were high for most recommendations. Conclusions: These updated EULAR recommendations provide consensus on RA management including safety, effectiveness and cost.publishersversionepub_ahead_of_prin

Assessment and Prediction of Adherence to Methotrexate Using Three Self-Report Questionnaires in Patients with Rheumatoid Arthritis

Introduction: Methotrexate (MTX) reduces rheumatoid arthritis activity and ameliorates the long-term functional status in these patients. To achieve this aim, patients need to take their medication regularly. Nevertheless, non-adherence to MTX still remains a considerable issue in the management of rheumatoid arthritis. Objective: This study aimed to estimate the adherence to methotrexate in patients with rheumatoid arthritis and to identify specific non-adherence risk factors. Methods: A cross-sectional study included 111 patients (mean age 56.2 ± 10.6 years, 78.4% female, and mean disease duration 6 years (3–13)). Three adherence self-assessment questionnaires were used: the Compliance-Questionnaire-Rheumatology (CQR19), the Medication Adherence Reports Scale (MARS-5), and the Visual Analogue Scale (VAS). We also collected demographic data, disease and treatment characteristics, and anxiety/depression estimation results (Hospital Anxiety and Depression Scale, HADS). Results: Adherence was identified in 48.6% of patients (COR19), 70.3% of patients (MARS-5), and 82.9% of patients (VAS questionnaire). All three questionnaires displayed a significant positive mutual correlation: CQR19 with MARS-5 and VAS (r = 0.364, r = 0.329, respectively, p p p = 0.030) using the MARS-5, female sex (0.264 (0.095–0.730), p = 0.010) according to the CQR19, and for a dose of methotrexate (0.881 (0.783–0.992), p = 0.036) using the VAS, while negative predictions were shown for comorbidity number (3.062 (1.057–8.874), p = 0.039) and depression (1.142 (1.010–1.293), p = 0.035) using the MARS-5 and for older age (1.041 (1.003–1.081), p = 0.034) according to the CQR19. The use of steroids was a significant positive predictor in all three questionnaires and remained an independent predictor for methotrexate adherence in the multivariate logistic regression. Conclusions: We showed non-adherence to methotrexate in a significant number of patients using all three questionnaires. Concomitant steroid therapy emerged as an independent positive predictor for adherence

EULAR recommendations for the management of rheumatoid arthritis with synthetic and biological disease-modifying antirheumatic drugs: 2022 update

Objectives: To provide an update of the EULAR rheumatoid arthritis (RA) management recommendations addressing the most recent developments in the field. Methods: An international task force was formed and solicited three systematic literature research activities on safety and efficacy of disease-modifying antirheumatic drugs (DMARDs) and glucocorticoids (GCs). The new evidence was discussed in light of the last update from 2019. A predefined voting process was applied to each overarching principle and recommendation. Levels of evidence and strengths of recommendation were assigned to and participants finally voted on the level of agreement with each item. Results: The task force agreed on 5 overarching principles and 11 recommendations concerning use of conventional synthetic (cs) DMARDs (methotrexate (MTX), leflunomide, sulfasalazine); GCs; biological (b) DMARDs (tumour necrosis factor inhibitors (adalimumab, certolizumab pegol, etanercept, golimumab, infliximab including biosimilars), abatacept, rituximab, tocilizumab, sarilumab and targeted synthetic (ts) DMARDs, namely the Janus kinase inhibitors tofacitinib, baricitinib, filgotinib, upadacitinib. Guidance on monotherapy, combination therapy, treatment strategies (treat-to-target) and tapering in sustained clinical remission is provided. Safety aspects, including risk of major cardiovascular events (MACEs) and malignancies, costs and sequencing of b/tsDMARDs were all considered. Initially, MTX plus GCs is recommended and on insufficient response to this therapy within 3-6 months, treatment should be based on stratification according to risk factors; With poor prognostic factors (presence of autoantibodies, high disease activity, early erosions or failure of two csDMARDs), any bDMARD should be added to the csDMARD; after careful consideration of risks of MACEs, malignancies and/or thromboembolic events tsDMARDs may also be considered in this phase. If the first bDMARD (or tsDMARD) fails, any other bDMARD (from another or the same class) or tsDMARD (considering risks) is recommended. With sustained remission, DMARDs may be tapered but should not be stopped. Levels of evidence and levels of agreement were high for most recommendations. Conclusions: These updated EULAR recommendations provide consensus on RA management including safety, effectiveness and cost