Deubiquitination of aryl hydrocarbon receptor (AhR) by USP21 negatively regulates Th17 cells differentiation.

Aryl hydrocarbon receptor (AhR) is a key transcription factor that modulates the differentiation of T helper 17 (Th17) cells. How AhR is regulated at the post-translational level in Th17 cells remains largely unclear. Here we identify USP21 as a newly defined deubiquitinase of AhR. We demonstrate that USP21 interacts with and stabilizes AhR by removing the K48-linked polyubiquitin chains from AhR. Interestingly, USP21 inhibits the transcriptional activity of AhR in a deubiquitinating-dependent manner. USP21 deubiquitinates AhR at the K432 residue, and the maintenance of ubiquitination on this site is required for the intact transcriptional activity of AhR. Moreover, the deficiency of USP21 promotes the differentiation of Th17 cells both in vitro and in vivo. Consistently, adoptive transfer of USP21 deficient naïve CD4+ T cells elicits more severe colitis in Rag1-/- recipients. Therefore, our study reveals a novel mechanism in which USP21 deubiquitinates AhR and negatively regulates the differentiation of Th17 cells.

Cannabinoid receptor 2 selective agonist alleviates systemic sclerosis by inhibiting Th2 differentiation through JAK/SOCS3 signaling.

Systemic sclerosis (SSc) poses a significant challenge in autoimmunology, characterized by the development of debilitating fibrosis of skin and internal organs. The pivotal role of dysregulated T cells, notably the skewed polarization toward Th2 cells, has been implicated in the vascular damage and progressive fibrosis observed in SSc. In this study, we explored the underlying mechanisms by which cannabinoid receptor 2 (CB2) highly selective agonist HU-308 restores the imbalance of T cells to alleviate SSc. Using a bleomycin-induced SSc (BLM-SSc) mouse model, we demonstrated that HU-308 effectively attenuates skin and lung fibrosis by specifically activating CB2 on CD4+ T cells to inhibit the polarization of Th2 cells in BLM-SSc mice, which was validated by Cnr2-specific-deficient mice. Different from classical signaling downstream of G protein-coupled receptors (GPCRs), HU-308 facilitates the expression of SOCS3 protein and subsequently impedes the IL2/STAT5 signaling pathway during Th2 differentiation. The deficiency of SOCS3 partially mitigated the impact of HU-308. Analysis of a cohort comprising 80 SSc patients and 82 healthy controls revealed an abnormal elevation in the Th2/Th1 ratio in SSc patients. The proportion of Th2 cells showed a significant positive correlation with mRSS score and positivity of anti-Scl-70. Administration of HU-308 to PBMCs and peripheral CD4+ T cells from SSc patients led to the upregulation of SOCS3, which effectively suppressed the aberrantly activated STAT5 signaling pathway and the proportion of CD4+IL4+ T cells. In conclusion, our findings unveil a novel mechanism by which the CB2 agonist HU-308 ameliorates fibrosis in SSc by targeting and reducing Th2 responses. These insights provide a foundation for future therapeutic approaches in SSc by modulating Th2 responses.

Global and regional epidemiology of psoriatic arthritis in patients with psoriasis: A comprehensive systematic analysis and modelling study.

OBJECTIVES: To provide a comprehensive analysis and modelling of the global epidemiology of psoriatic arthritis (PsA) in patients with psoriasis. METHODS: We reviewed and analysed PsA epidemiology studies over the past 45 years. A Bayesian hierarchical linear mixed model was developed to provide comprehensive age- and sex-specific epidemiologic estimates in different countries and regions. RESULTS: Three hundred and sixty-three studies were systematically reviewed. The incidence of PsA in patients with psoriasis varied from 2.31 per 1000 person-years in the United Kingdom to 74.00 per 1000 person-years in several Western European countries. The global prevalence of PsA in patients with psoriasis is estimated to be 17.58% (3.33%, 43.69%). Regionally, the overall prevalence of PsA in patients with psoriasis varies from 7.62% (4.18%, 12.28%) in Australasia to 26.59% (18.89%, 35.76%) in North America. The Caribbean and Central Latin America also have relatively high prevalence and are estimated at 23.14% (14.06%, 35.17%) and 22.81% (14.36%, 32.25%), respectively. The prevalence of PsA is higher in adults than children (23.93% vs 8.59%) and also slightly higher in females than males (19.14% vs 16.01%). CONCLUSIONS: This study provides valuable insights into the global epidemiology of PsA. It also serves as a useful resource for researchers in areas lacking relevant studies. These findings have important implications for clinicians managing the course of PsA and for health policymakers in resource allocation.

2023 International Consensus Guidance for the use of Tripterygium Wilfordii Hook F in the treatment of active rheumatoid arthritis.

BACKGROUND: Rheumatoid arthritis (RA) is a chronic autoimmune disorder that affects the joints and produces pain, swelling, and stiffness. It has a lifetime prevalence of up to 1% worldwide. An extract of Tripterygium wilfordii Hook F (TwHF), a member of the Celastraceae herbal family widely available in south China, has been used for treatment of RA since 1960s. METHODS: The current consensus practice guidance (CPG) aims to offer guidance on the application of TwHF in the clinical management of active RA. The CPG followed World Health Organisation (WHO)'s recommended process, carried out three systematic reviews to synthesize data from 19 randomised controlled trials (RCT) involving 1795 participants. We utilized Grading of Recommendations, Assessment, Development and Evaluation (GRADE) to evaluate certainty of evidence and derive recommendations. We rigorously followed The Appraisal of Guidelines for Research and Evaluation II (AGREE II) as conduct guides to minimise bias and promote transparency. RESULTS: There was no obvious difference between TwHF monotherapy and methotrexate (MTX) monotherapy on ACR20 (RCT = 2, N = 390, RR = 1.06, 95%CI 0.90-1.26, moderate certainty), ACR50 (RCT = 3, N = 419, RR = 1.03, 95%CI 0.80-1.34, moderate certainty), ACR70 (RCT = 2, N = 390, RR = 1.12, 95%CI 0.69-1.79, low certainty). TwHF monotherapy may be better than salicylazosulfapyridine monotherapy on ACR20 and the effect may be similar on ACR50 and ACR70. Seven RCTs compared MTX combined with TwHF versus MTX monotherapy, and the meta-analysis results favoured combination therapy group on ACR20 (RCT = 3, N = 470, RR = 1.44, 95%CI 1.28-1.62, moderate certainty), ACR50 (RCT = 4, N = 500, RR = 1.88, 95%CI 1.56-2.28, moderate certainty) and ACR70 (RCT = 2, N = 390, RR = 2.12, 95%CI 1.40-3.19, low certainty). We found no obvious difference between groups on critical safety outcomes, including infection (RCT = 3, N = 493, RR = 1.37, 95%CI 0.84-2.23), liver dysfunction (RCT = 5, N = 643, RR = 1.14, 95%CI 0.71-1.85), renal damage (RCT = 3, N = 450, RR = 2.20, 95%CI 0.50-9.72). CONCLUSION: Upon full review of the evidence, the guidance panel reached consensus on recommendations for the use of TwHF in people with active RA, either as monotherapy or as combination therapy with MTX.

Prevalence of psoriatic arthritis in Chinese population with psoriasis: A multicenter study conducted by experienced rheumatologists.

BACKGROUND: Reports on the prevalence of psoriatic arthritis (PsA) among Chinese patients with psoriasis are very limited. This study, conducted by rheumatologists, estimated the prevalence of PsA in a large number of Chinese patients with psoriasis. METHODS: Consecutive patients with a confirmed diagnosis of psoriasis attending nine dermatology clinics in five hospitals were recruited. All psoriasis patients were asked to complete a questionnaire comprising 16 questions to identify possible cases of PsA. All patients with one or more positive answers to the questionnaire were evaluated by two experienced rheumatologists. RESULTS: A total of 2434 psoriasis patients, including 1561 males and 873 females, were enrolled. Both the questionnaire and rheumatologists' examinations were completed in the dermatology clinics. The results identified 252 patients with PsA, comprising 168 males and 84 females. The overall prevalence of PsA among psoriasis patients was 10.4% (95% confidence interval [95% CI], 9.1%-11.7%). By sex, the prevalence was 10.8% (95% CI, 9.2%-12.5%) for males and 9.6% (95% CI, 7.7%-11.9%) for females and there was no significant sex difference in the prevalence of PsA (P = 0.38). Of the 252 PsA patients, 125 (49.6%, 95% CI, 41.3%-59.1%) were newly diagnosed by rheumatologists. Consequently, the prevalence of undiagnosed PsA among psoriasis patients was 5.2% (95% CI, 4.4%-6.2%). CONCLUSION: The prevalence of PsA in the Chinese population with psoriasis is about 10.4%, which is almost double that of previous reports in the Chinese population, but lower than that in Caucasians.

SIRT3 alleviates imiquimod-induced psoriatic dermatitis through deacetylation of XBP1s and modulation of TLR7/8 inducing IL-23 production in macrophages.

Current evidence suggests that IL-23, IL-6, and TNF-α play pivotal roles in the pathogenesis of psoriasis. Although it has been established that Sirtuin 3 (SIRT3) mediates the inflammatory process, the underlying mechanisms remain largely unclear. Herein, we substantiated that the inhibition or deletion of SIRT3 increased the acetylation level of spliced form of X-box binding protein 1 (XPB1s), enhancing its transcriptional activity and IL-23a production. Pharmacologically inhibition of XBP1s with MKC8866 downregulated the expression of inflammatory cytokines in SIRT3-inhibited or Sirt3-KO BMDMs stimulated by IMQ. Inhibition or knockdown of SIRT3 could exacerbate psoriasis-like skin inflammation in an imiquimod-induced psoriasis-like mouse model. Besides, a decrease in SIRT3 expression was observed in the macrophages of psoriasis patients, which increased the expression and acetylation level of XBP1s. Overall, we provide compelling evidence of the crucial role of SIRT3 in the IL-23 axis in psoriatic inflammation and novel molecular insights into the anti-inflammatory effects of SIRT3.

Continuation, reduction, or withdrawal of tofacitinib in patients with rheumatoid arthritis achieving sustained disease control: a multicenter, open-label, randomized controlled trial.

BACKGROUND: Rheumatoid arthritis (RA), a chronic systemic autoimmune disease, is characterized by synovitis and progressive damage to the bone and cartilage of the joints, leading to disability and reduced quality of life. This study was a randomized clinical trial comparing the outcomes between withdrawal and dose reduction of tofacitinib in patients with RA who achieved sustained disease control. METHODS: The study was designed as a multicenter, open-label, randomized controlled trial. Eligible patients who were taking tofacitinib (5 mg twice daily) and had achieved sustained RA remission or low disease activity (disease activity score in 28 joints [DAS28] ≤3.2) for at least 3 months were enrolled at six centers in Shanghai, China. Patients were randomly assigned (1:1:1) to one of three treatment groups: continuation of tofacitinib (5 mg twice daily); reduction in tofacitinib dose (5 mg daily); and withdrawal of tofacitinib. Efficacy and safety were assessed up to 6 months. RESULTS: Overall, 122 eligible patients were enrolled, with 41 in the continuation group, 42 in the dose-reduction group, and 39 in the withdrawal group. After 6 months, the percentage of patients with a DAS28-erythrocyte sedimentation rate (ESR) of <3.2 was significantly lower in the withdrawal group than that in the reduction and continuation groups (20.5%, 64.3%, and 95.1%, respectively; P  < 0.0001 for both comparisons). The average flare-free time was 5.8 months for the continuation group, 4.7 months for the dose reduction group, and 2.4 months for the withdrawal group. CONCLUSION: Withdrawal of tofacitinib in patients with RA with stable disease control resulted in a rapid and significant loss of efficacy, while standard or reduced doses of tofacitinib maintained a favorable state. TRIAL REGISTRATION: Chictr.org, ChiCTR2000039799.

An interaction between the inflammatory condition and the hypercoagulable condition occurs in primary Sjögren syndrome.

This study aimed to assess the D-dimer level in patients with primary Sjögren syndrome (pSS), uncover its relationship with clinical symptoms, and appraise its predictive value in discriminating disease activity. The laboratory parameters of 101 consecutive patients with pSS and 101 healthy controls were analyzed and compared. Patients were divided into two subgroups according to their D-dimer levels, for the comparison of clinical features. Pearson's correlations were used to measure the relationships between D-dimer levels and other variables. The area under the curve (AUC) was calculated to predict disease activity. The erythrocyte sedimentation rate (ESR), high-sensitivity C-reactive protein (hsCRP) level, and D-dimer level were each higher in patients with pSS than in healthy controls. Compared with the low-D-dimer-level patients, those with elevated D-dimer levels exhibited higher ESRs (p < 0.0001) and higher levels of hsCRP (p < 0.0001), fibrinogen (p < 0.0001), and immunoglobulin A (p = 0.002). Cases with elevated D-dimer levels were prone to be more severe, based on ESSDAI evaluation (p < 0.0001). Patients with higher D-dimer levels had more articular involvement (p < 0.0001), which was significantly correlated with both the ESR (r = 0.21, p = 0.03) and hsCRP level (r = 0.56, p = 0.001). The D-dimer level may help to discriminate low disease activity from moderate/high disease activity (AUC = 0.754). The D-dimer level was correlated positively with both the ESR and hsCRP level in patients with pSS. The ESR and levels of hsCRP, fibrinogen, and disease activity were higher in the elevated D-dimer level group. The D-dimer level was demonstrated to have predictive value in differentiating pSS disease activity. Key Points •D-Dimer was higher in patients with pSS. •D-Dimer may help for predicting the disease activity in patients with pSS.

Equivalent cut-off values of Bath Ankylosing Spondylitis Disease Activity Index corresponding to Ankylosing Spondylitis Disease Activity Score cut-off values.

OBJECTIVES: To define the equivalent cut-off values of Bath ankylosing Spondylitis Disease Activity Index (BASDAI) for discriminating disease activity corresponding to Ankylosing Spondylitis Disease Activity Score (ASDAS) cut-off values, and to determine the equivalent change units for determining the clinically improvement between ΔBASDAI and ΔASDAS-CRP. METHODS: 475 patients with axial spondyloarthritis (axSpA) whose data on BASDAI and ASDAS were available were included. Among them, 154 (32.4%) patients whose data on ΔBASDAI and ΔASDAS-CRP were available. Receiver-operator curve (ROC) with area under curve (AUC) was used to determine the BASDAI cut-off values that best corresponded to ASDAS-CRP. The Cohen's kappa was utilised to assess the degree of agreement between disease activity states based on BASDAI and ASDAS cut-off values, and clinically improvement between ΔBASDAI and ΔASDAS-CRP. RESULTS: According to the ASDAS-CRP, 88 (18.6%), 130 (27.4%), 191 (40.1%) and 66 (13.9%) patients were classified as inactive, moderate, high and very high disease activities, respectively. ROC revealed that BASDAI values 1.6 (AUC: 0.948), 2.9 (AUC: 0.790) and 3.8 (AUC: 0.875) best corresponded to ASDAS-CRP values 1.3, 2.1 and 3.5, respectively. The degree of agreement between them was moderate (kappa: 0.527). The ΔBASDAI 1.6 (AUC: 0.745) and 2.0 (AUC: 0.708) best corresponded to the ΔASDAS-CRP 1.1 (minimal clinically important improvement) and 2.0 (major improvement), respectively. The degree of agreement was good (kappa: 0.685). CONCLUSIONS: The BASDAI values 1.6, 2.9 and 3.8 correspond to ASDAS-CRP values 1.3, 2.1 and 3.5, respectively. The ΔBASDAI 1.6 and 2.0 best correspond to the ΔASDAS-CRP 1.1 and 2.0, respectively.

Platelet to albumin ratio is an independent indicator for disease activity in ankylosing spondylitis.

The objective of this study is to characterize the association between platelet to albumin ratio (PAR) and disease activity in patients with ankylosing spondylitis (AS) and axial psoriatic arthritis (axPsA). Baseline platelet count, albumin, PAR, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), Bath ankylosing spondylitis disease index (BASDAI), Bath ankylosing spondylitis functional index (BASFI), and ankylosing spondylitis disease activity score (ASDAS) were collected from patients with a definitive diagnosis of AS or axPsA. Spearman's correlation analysis, quantile regression, and receiver operating characteristic (ROC) curves were performed. Four hundred forty-six patients with AS and 68 patients with axPsA were included. AS patients had higher CRP, ASDAS-CRP, and ASDAS-ESR than axPsA patients (median: CRP, 6.8 vs. 3.5 mg/L, p = 0.02; ASDAS-CRP, 2.32 vs.1.93, p = 0.001; ASDAS-ESR, 2.57 vs.1.97, p = 0.007; respectively). Platelet count, albumin, PAR, ESR, BASDAI, and BASFI did not significantly differ between the two populations (all p > 0.05). In AS patients, PAR was positively correlated with BASDAI (r = 0.204, p < 0.01), BASFI (r = 0.24, p < 0.01), ASDAS-CRP (r = 0.475, p < 0.01), and ASDAS-ESR (r = 0.483, p < 0.01), while these coefficients were not significant in axPsA patients. The quantile regression further confirmed that, in AS patients, PAR was independently associated with BASDAI, BASFI, ASDAS-CRP, and ASDAS-ESR at their individual quantiles (all p < 0.01). However, in axPsA patients, PAR was not significantly associated with these disease activities. The optimal cut-off value of PAR for AS disease activity was 5.87, with an AUC of 0.745, a sensitivity of 72.4%, and a specificity of 71%. PAR could serve as an alternative indicator for AS disease activity. Key Points • Platelet to albumin ratio is independently associated with ankylosing spondylitis disease activity. • Platelet to albumin ratio could serve as an alternative indicator for ankylosing spondylitis disease activity.

Risk of Erectile Dysfunction in Male Patients with Gout Treated with Febuxostat or Allopurinol: A Propensity Score-Matched Cohort Study.

OBJECTIVE: To evaluate and compare the risk of erectile dysfunction (ED) associated with the use of allopurinol and febuxostat in adult male gout patients. METHODS: We conducted a cohort study using TriNetX (Cambridge, MA, USA), a global federated health research network that provides real-time electronic medical record datasets. We analyzed and compared the associated risk of ED in gout patients who started taking allopurinol or febuxostat within 12 months. Propensity score matching was performed to adjust for demographic variables, comorbidities, and medication use. Kaplan-Meier analysis was used to estimate the probability of the outcome of interest. The hazard ratio (HR) and associated confidence intervals were calculated along with the proportionality test using R's Survival Package v3.2-3. RESULTS: We identified 679,862 patients with gout among 107,517,445 patients in the database. Of these patients, 24,000 were treated with febuxostat and 299,726 with allopurinol. After propensity matching, 9075 patients receiving febuxostat without allopurinol (febuxostat group) and 9075 corresponding patients receiving allopurinol without febuxostat (allopurinol group) were analyzed for comparison. Among all male patients over 19 years of age, febuxostat was associated with a significantly higher risk of ED versus allopurinol (HR 1.354; 95% confidence interval (CI) 1.003-1.829; log rank test, p = 0.047). After subgroup analysis, in gout patients aged 19-64 years, a significantly higher incidence of ED was observed in the febuxostat group than in the allopurinol group (HR 2.002, 95% CI 1.282-3.126). The risk of ED did not differ significantly between the allopurinol and febuxostat groups in gout patients older than 65 years. CONCLUSIONS: Febuxostat may be associated with a higher risk of ED than allopurinol in adult male patients with gout. Future large-scale prospective studies are warranted to confirm our results.

Regulation of type I interferon signature by VGLL3 in the fibroblast-like synoviocytes of rheumatoid arthritis patients via targeting the Hippo pathway.

BACKGROUND: The upregulation of interferon (IFN)-stimulated genes induced by type I IFNs (namely type I IFN signature) in rheumatoid arthritis (RA) patients had implications in early diagnosis and prediction of therapy responses. However, factors that modulate the type I IFN signature in RA are largely unknown. In this study, we aim to explore the involvement of VGLL3, a homologue of the vestigial-like gene in Drosophila and a putative regulator of the Hippo pathway, in the modulation of type I IFN signature in the fibroblast-like synoviocytes (FLS) of RA patients. METHODS: FLS were isolated from RA and osteoarthritis (OA) patients. Expression of VGLL3 in the synovial tissues and FLS was analyzed by immunohistochemistry and PCR. RNA sequencing was performed in RA-FLS upon VGLL3 overexpression. The expression of IFN-stimulated genes was examined by PCR and Western blotting. RESULTS: VGLL3 was upregulated in the RA synovium and RA-FLS compared to OA. Overexpression of VGLL3 promoted the expression of IFN-stimulated genes in RA-FLS. The expression of STAT1 and MX1 was also upregulated in RA synovium compared to OA and was associated with the expression of VGLL3 in RA and OA patients. VGLL3 promoted the IRF3 activation and IFN-ß1 expression in RA-FLS. Increased IFN-ß1 induced the expression of IFN-stimulated genes in RA-FLS in an autocrine manner. VGLL3 also modulated the expression of the Hippo pathway molecules WWTR1 and AMOTL2, which mediated the regulation of IRF3 activation and IFN-ß1 production by VGLL3 in RA-FLS. CONCLUSIONS: VGLL3 drives the IRF3-induced IFN-ß1 expression in RA-FLS by inhibiting WWTR1 expression and subsequently promotes the type I IFN signature expression in RA-FLS through autocrine IFN-ß1 signaling.

Differentiating psoriatic arthritis sine psoriasis from seronegative rheumatoid arthritis-Experiences from five patients.

Psoriatic arthritis (PsA) without skin lesions is frequently confused with seronegative rheumatoid arthritis (RA). In this study, we aimed to promote diagnostic accuracy. Five PsA patients with no skin lesions were reviewed. We analyzed the clinical characteristics of these patients. All patients had multiple peripheral arthritis as well as axial involvement, and had been misdiagnosed with RA for several years initially. They developed severe deformation as a result of delayed diagnosis and inadequate treatment. Four patients had nail changes and one had a family history of psoriasis. They had hallmarks of PsA such as dactylitis, enthesitis, and distal interphalangeal arthritis. Ultrasound detection frequently revealed inflammation in the enthesis and extra-synovial areas. Nail psoriasis, dactylitis, enthesitis, distal interphalangeal arthritis, and extra-synovial inflammation would help to differentiate PsA from seronegative RA.