The current pandemic coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) calls urgently for effective therapies. Anti-malarial medicine ...chloroquine (CQ) and particularly its chemical analogue hydroxychloroquine (HCQ) have been recommended as promising candidate therapeutics that are now under either compassionate off-label use or clinical trials for the treatment of COVID-19 patients. However, there are public concerns and disputes about both the safety and efficacy of CQ and HCQ for this new application. Given the fact that for decades HCQ has been approved as an immunomodulatory drug for the long term treatment of chronic rheumatic diseases, as experienced rheumatologists, we would like to share our thoughts in this regard and trigger a brainstorm among clinical care providers for exchanging their diverse opinions on this urgent topic.
Objectives
Adiponectin (AD) highly expressed in synovial tissue correlates closely with progressive bone erosion in rheumatoid arthritis (RA). However, it remains unknown whether AD receptor mediates ...the pathogenesis of RA. This study aimed to investigate the effects of adiponectin receptor 1 (AdipoR1) signaling on synovial inflammation and joint damage in collagen-induced arthritis.
Methods
AD and AdipoR1 expression in synovial tissue of RA and osteoarthritis (OA) patients were tested by PCR and western blotting. The frequency of AdipoR1 on RA synovial fibroblasts (RASFs) was examined by flow cytometry after stimulation with AD, IL-6, or TNF-α. AdipoR1 was knocked down in human RASF cell line (MH7A) and CIA mice joints using lentiviral particles carrying the AdipoR1 short hairpin RNA (shAdipoR1). Both the proliferation and apoptosis of MH7A and the secretion of inflammatory factors from MH7A were examined in vitro. The therapeutic effect of local AdipoR1 inhibition on CIA mice was assessed in vivo.
Results
Both the expression of AD and AdipoR1 were significantly higher in RA synovial tissue. AdipoR1 on RASFs was upregulated by AD. Silencing AdipoR1 remarkably reduced lipopolysaccharides-induced proliferation and promoted the apoptosis of MH7A. Moreover, AdipoR1 knockdown inhibited the release of inflammatory factors in vitro. In CIA mice, local AdipoR1 inhibition effectively decreased joint inflammation and alleviated bone destruction via suppressing RANKL and RANKL/OPG ratio in vivo.
Conclusions
AdipoR1 signaling participates in the process of synovial inflammation and joint damage in CIA. Local blockade of AdipoR1 might be a new target for the clinical treatment of RA.
Key points
• Local AdipoR1 inhibition decreased joint inflammation and alleviated bone destruction in CIA.
Objective
Elevated interleukin‐10 (IL‐10) levels in patients with systemic lupus erythematosus (SLE) have B cell–promoting effects, contributing to autoantibody production and tissue damage. We aimed ...to characterize up‐regulated IL‐10+ B cell subsets and dysregulated IL10 expression in SLE B cells for new therapeutic options.
Methods
Proportions of Th10 and IL‐10+ B cell subsets in peripheral blood mononuclear cells (PBMCs) were assessed using flow cytometry. The IL10 3′‐untranslated region (3′‐UTR) dual‐luciferase vector was constructed and cotransfected with small interfering RNA (siRNA), microRNA (miRNA) mimics, or miRNA inhibitors into Raji cells. Transcript levels were quantified using TaqMan assays.
Results
Culture conditions that induced IL‐10+ Breg cells in healthy controls resulted in expansion of IL‐10+ double‐negative 2 (DN2; IgD−CD27−CD21−CD11c+) B cells in SLE PBMCs. Proportions of IL‐10+ DN2, but not those of IL‐10− DN2, correlated with disease activity and levels of antibodies to double‐stranded DNA (dsDNA) (r = 0.60, P = 0.03 for cohort 1; r = 0.38, P = 0.03 for cohort 2), and were associated with high levels or seropositivity of anti‐Sm (P = 0.03 for cohort 1; P = 0.01 for cohort 2) and IgG anticardiolipin (P < 0.01 for cohort 1; P = 0.02 for cohort 2) in SLE patients from 2 cohorts, of mainly African American subjects (cohort 1) and of Asian subjects (cohort 2). Proportions of Th10 (CD45RA−CXCR5−CXCR3+PD‐1highCD4+) cells correlated with IL‐10+ DN2 frequencies (r = 0.60, P < 0.01 for cohort 2), antinuclear antibody titers (r = 0.52, P = 0.01 for cohort 2), and proteinuria levels (r = 0.72, P < 0.01 for cohort 2) in SLE patients. Screening of predicted IL10 3′‐UTR–targeting miRNAs in SLE B cells identified miRNA‐17‐5p (miR‐17‐5p) and miR‐20a‐5p, with their levels inversely correlated with IL10 (r = −0.47, P < 0.01 for miR‐17‐5p; r = −0.37, P = 0.03 for miR‐20‐5p) and transcription factor E2F2 (r = −0.48, P = 0.04 for miR‐17‐5p; r = −0.45, P = 0.05 for miR‐20‐5p). In Raji cells, knockdown of E2F2 expression resulted in increased levels of miR‐17‐5p and miR‐20a‐5p and decreased IL10 messenger RNA (mRNA) and protein levels, and overexpression and inhibition of miR‐17‐5p down‐regulated and up‐regulated, respectively, IL10 mRNA levels, suggesting regulation of IL10 expression by an E2F2‐miR‐17‐5p loop.
Conclusion
IL‐10 promotes extrafollicular autoimmune responses in patients with active SLE, which might be dampened by targeting the E2F2–miR‐17‐5p circuitry.
Recently, the traditional Chinese medicine Tripterygium wilfordii Hook f (TwHF) of the Celastraceae family has attracted increasing attention for its potential therapeutic application in patients ...with rheumatoid arthritis (RA). It is well accepted that TwHF exerts the antirheumatic activity and mainly depends on its potent anti-inflammatory property. To further explore the therapeutic potential of the well-defined TwHF-derived single compound - celastrol in RA, we study the therapeutic efficacy of celastrol on bone erosion in collagen-induced arthritis (CIA) mice and delineate its effects on osteoclast differentiation and functions in RANKL-induced osteoclast precursors RAW264.7 cell line. In CIA mice, daily injection of celastrol (beginning on day 28 after arthritis induction) markedly suppressed arthritis, and reduced bone damage in the joints as demonstrated by histology and bone micro-computed tomography (CT). The effects were accompanied by reductions of osteoclast cells in joints, serum tartrate-resistant acid phosphatase (TRAP) 5b, and expression of osteoclastic genes (Trap, Ctsk, Ctr, Mmp-9) and transcriptional factors (c-Fos, c-Jun and NFATc1). When RAW264.7 cells were treated with RANKL, celastrol inhibited the formation of TRAP+ multinucleated cells and the bone-resorbing activity in dose-dependent manners. Furthermore, celastrol reduced the RANKL-induced expression of osteoclastic genes and transcriptional factors, as well as phosphorylation of NF-kB and mitogen-activated protein kinases (MAPK). These findings show that celastrol could directly inhibit osteoclast formation and function, suggesting a novel therapeutic strategy of celastrol for managing RA, especially in preventing bone destruction.
Rapid progressive interstitial lung disease (RP-ILD) is the leading cause of anti-melanoma differentiation associated protein 5 antibody positive dermatomyositis (anti-MDA5
DM) related death. ...Elevated serum B-cell activating factor (BAFF) levels have been implicated in connective tissue diseases associated ILD. Here, we evaluate whether BAFF could be a prognostic biomarker for predicting RP-ILD in anti-MDA5
DM patients.
Serums were collected from 39 patients with anti-MDA5
DM (20 with RP-ILD and 19 with non-RP-ILD), 20 antisynthase syndrome (ASS) patients and 20 healthy controls (HC). BAFF concentration was measured by an enzyme-linked immunosorbent assay.
Serum BAFF level was higher in anti-MDA5
DM patients than those in ASS patients and HC (3882.32 ± 1880.09 vs. 2540.89 ± 1403.04 and 2486.28 ± 767.97 pg/mL, p = 0.0056 and 0.0038, respectively). Within anti-MDA5
DM groups, RP-ILD patients exhibited higher BAFF concentration than non-RP-ILD group (4549.78 ± 1839.97 vs. 3297.28 ± 1794.69 pg/mL, p = 0.04). The BAFF concentration was positively correlated with levels of C-reactive protein (CRP), dehydrogenase (LDH) and cytokeratin (CK) in anti-MDA5
DM patients (r = 0.350, p = 0.035; r = 0.393, p = 0.016; r = 0.518, p = 0.001; respectively). The best cut-off value of BAFF concentration was 2971.5 pg/mL by ROC curve (AUC area = 0.690, p = 0.045) and BAFF > 2971.5 pg/mL was an independent risk factor for RP-ILD using multivariate analysis (OR = 9.389, 95% CI = 1.609-54.769; p = 0.013).
Serum BAFF could be a useful prognostic biomarker for early detecting RP-ILD risk in anti-MDA5
DM patients.
We previously reported that adiponectin (AD) promotes naïve T cell differentiation into Th17 cells and participates in synovial inflammation and the bone erosion process in patients with rheumatoid ...arthritis. Here, we use a T cell lineage adiponectin receptor 1 (AdipoR1) conditional knockout model to investigate the role of AdipoR1 in Th17 differentiation. RNA-sequencing (RNA-seq) demonstrated that
knockout reduced the expression of a variety of T cell related genes, with
showing the greatest level of down-regulation. AdipoR1 deficiency inhibited Th17 cell differentiation
and ameliorated joint inflammation in antigen-induced arthritis mice. Moreover, AdipoR1-deficent CD4
T cells displayed reduced Hypoxia-Inducible Factor-1α expression leading to glycolysis inhibition during naïve CD4
T cell differentiation into Th17 cells. We describe a novel function of AdipoR1 in regulating Th17 cell differentiation through modulating HIF-1α-dependent glycolysis.
We have previously reported that adiponectin (AD), an adipokine that is secreted by adipocytes, correlates well with progressive bone erosion in rheumatoid arthritis (RA). The exact mechanism of AD ...in promoting joint destruction remains unclear. Osteopontin (OPN) is required for osteoclast recruitment. We hypothesized that AD exacerbates bone erosion by inducing OPN expression in synovial tissue. This study aimed to evaluate a novel role for AD in RA.
The serum levels of AD and OPN were determined in 38 patients with RA, 40 patients with osteoarthritis (OA), and 20 healthy controls using enzyme-linked immunosorbent assay (ELISA). AD and OPN production were measured by double immunofluorescence in RA and OA synovial tissue. Quantitative real-time PCR and immunofluorescence were used to evaluate the mRNA and protein expression levels of OPN in RA synovial fibroblasts (RASFs) and OA synovial fibroblasts after pre-incubation with AD, respectively. Migration of the RAW264.7 osteoclast precursor cell line was assessed using the Transwell migration assay and co-culture system. Bone destruction and osteoclastogenesis were assessed by immunohistochemical staining, microcomputed tomography and tartrate-resistant acid phosphatase (TRAP) staining in AD-treated collagen-induced arthritis (CIA) mice with or without OPN silencing. The expression levels of OPN and integrin α
β
in the ankle joint tissues of the mice were examined by double immunofluorescence.
Our results indicated that the AD and OPN expression levels increased noticeably and were associated with each other in the RA serum. The AD distribution was coincident with that of OPN in the RA synovial tissue. AD stimulation of RASFs increased OPN production in a dose-dependent manner. AD-treated RASFs promoted RAW264.7 cell migration, and the effect was blocked with a specific antibody against OPN. Silencing of OPN using lentiviral-OPN short hairpin RNA reduced the number of TRAP-positive osteoclasts and the extent of bone erosion in the AD-treated CIA mice. When bound to integrin α
β
, OPN functions as a mediator of AD and osteoclasts.
Our study provides new evidence of AD involvement in bone erosion. AD induces the expression of OPN, which recruits osteoclasts and initiates bone erosion. These data highlight AD as a novel target for RA treatment.
We previously reported that IL-29, a newly described member of interferon (IFN) family, was overexpressed in blood and synovium of rheumatoid arthritis (RA) patients and triggered proinflammatory ...cytokine IL-6 and IL-8 mRNA expression in RA synovial fibroblasts (RA-FLS). This suggests that IL-29 has an important role in synovial inflammation. Toll-like receptors (TLRs) also activate RA-FLS to produce inflammatory mediators including tumor necrosis factor α (TNF-α) and IL-1β in RA-FLS. Since the TLR family plays an early role in the innate immune response and the subsequent induction of the adaptive immune response, we hypothesize that IL-29 interacts with TLRs in RA inflammation. This study aimed to investigate the effect of IL-29 on TLR-mediated proinflammatory cytokine production in RA-FLS.
The mRNA level of IL-29 receptors (IL-28Rα and IL-10R2) in RA-FLS was determined by semi-quantitative RT- PCR. IL-6 and IL-8 mRNA expressions in RA-FLS were evaluated by real-time PCR after pre-incubation with IL-29 and subsequent stimulation with peptidoglycan (PGN, TLR2 ligand), or polycytidylic acid (poly(I:C), TLR3 ligand), or lipopolysaccharide (LPS, TLR4 ligand) . The production of TLR2, 3, and 4 in RA-FLS after IL-29 stimulation was also assessed by real-time PCR and flow cytometry. IL-29 mRNA and protein expression in RA-FLS after stimulation with PGN, poly(I:C), or LPS were measured by real-time PCR and enzyme-linked immunosorbent assay (ELISA), respectively.
The IL-29 receptor complex (IL-28Rα and IL-10R2) was identified in RA-FLS. IL-29 enhanced TLR-mediated IL-6 and IL-8 expression in RA-FLS. IL-29 upregulated expression of TLR2, 3 and 4 in RA-FLS. Exposure to PGN, poly(I:C) or LPS triggered IL-29 production by RA-FLS.
We show for the first time that IL-29 enhances TLR-induced proinflammatory cytokine production in RA-FLS via upregulation of TLRs.
Abstract
Environmental exposures interact with genetic factors has been thought to influence susceptibility of systemic lupus erythematosus (SLE) development. To evaluate the effects of environmental ...exposures on SLE, we conducted a population-based cohort study across Jiangsu Province, China, to examine the associations between the living environment including air and water pollution, population density, economic income level, etc. and the prevalence and mortality of hospitalized SLE (h-SLE) patients. A total of 2231 h-SLE patients were retrieved from a longitudinal SLE database collected by the Jiangsu Lupus Collaborative Group from 1999 to 2009. The results showed that: It existed regional differences on the prevalence of h-SLE patients in 96 administrative districts; The distribution of NO
2
air concentration monitored by atmospheric remote sensors showed that three of the ultra-high-prevalence districts were located in the concentrated chemical industry emission area; h-SLE patient prevalence was positively correlated with the excessive levels of nitrogen in drinking water; The positive ratio of pericarditis and proteinuria was positively correlated with the prevalence of h-SLE patients and pollution not only induced a high h-SLE patient prevalence but also a higher mortality rate, which might be attributed to NOx pollution in the air and drinking water. In summary, our data suggested that NOx in air and drinking water may be one of the important predispositions of SLE, especially for patients with renal involvement.
Primary Sjögren's syndrome (pSS) is a chronic systemic autoimmune disease which has focal lymphocytic infiltration including a majority of CD4+ T cells. This study was to investigate the correlation ...of peripheral granzyme B (GranzB)-expressing CD4+ T cells with disease severity and histological lesion in patients with pSS.
We recruited 116 pSS and 46 health control (HC) using flow cytometry to examine the percentage of CD4+GranzB+CTLs in the peripheral blood, and immunofluorescence to test their expression in the labial gland.
The percentage of CD4+GranzB+CTLs was significantly upregulated in pSS than in HC (7.1 ± 4.9% vs 3.1 ± 1.9%, p < 0.0001) and positive correlation with ESSDAI. The frequency of them was markedly higher in pSS with extraglandular manifestations. After excluding the other risk factors associated with pSS, they were still related to ESSDIA and extraglandular manifestations independently (p < 0.05), and they are the risk factor of extraglandular involvement (odds ratio = 1.928). Moreover, they could be observed in the LSGs. ROC curve analysis indicated that the area under the curve (AUC) of CD4+GranzB+CTLs was 0.796 to predict the activity of pSS and 0.851 to presume extraglandular manifestations. The best diagnostic cutoff point was 4.865 for pSS patients.
In this study, we provide new evidence indicating the involvement of CD4+GranzB+CTLs over activation in the pathophysiology of pSS, which may serve as a new biomarker to evaluate the activity and severity of pSS.
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