A 4-trifluoromethyl analogue of celecoxib inhibits arthritis by suppressing innate immune cell activation

Transition-metal-free synthesis of trifluoromethylated benzoxazines via a visible-light-promoted tandem difunctionalization of o-vinylanilides with trifluoromethylsulfinate

A Umemoto's reagent-free and cost-effective method for synthesis of trifluoromethylated benzoxazines by 9,10-phenanthrenedione visible-light photocatalysis is described in this article.

Mucosal-Associated Invariant T Cells in Autoimmune Diseases

Mucosal-associated invariant T (MAIT) cells are innate T cells restricted by MHC-related molecule 1 (MR1). MAIT cells express semi-invariant T-cell receptors TRAV1-2-TRAJ33/12/20 in humans and TRAV1-TRAJ33 in mice. MAIT cells recognize vitamin B2 biosynthesis derivatives presented by MR1. Similar to other innate lymphocytes, MAIT cells are also activated by cytokines in the absence of exogenous antigens. MAIT cells have the capacity to produce cytokines, such as IFNγ, TNFα, and IL-17, and cytotoxic proteins, including perforin and granzyme B. MAIT cells were originally named after their preferential location in the mucosal tissue of the gut, but they are also abundant in other peripheral organs, including the liver and lungs. In humans, the frequency of MAIT cells is high in peripheral blood, and these cells constitute approximately 5% of circulating CD3⁺ cells. Their abundance in tissues and rapid activation following stimulation have led to great interest in their function in various types of immune diseases. In this review, first, we will briefly introduce key information of MAIT cell biology required for better understating their roles in immune responses, and then describe how MAIT cells are associated with autoimmune and other immune diseases in humans. Moreover, we will discuss their functions based on information from animal models of autoimmune and immunological diseases.

Urokinase plasminogen activator and receptor promote collagen-induced arthritis through expression in hematopoietic cells

The plasminogen activation (PA) system has been implicated in driving inflammatory arthritis, but the precise contribution of PA system components to arthritis pathogenesis remains poorly defined. Here, the role of urokinase plasminogen activator (uPA) and its cognate receptor (uPAR) in the development and severity of inflammatory joint disease was determined using uPA- and uPAR-deficient mice inbred to the strain DBA/1J, a genetic background highly susceptible to collagen-induced arthritis (CIA). Mice deficient in uPA displayed a near-complete amelioration of macroscopic and histological inflammatory joint disease following CIA challenge. Similarly, CIA-challenged uPAR-deficient mice exhibited significant amelioration of arthritis incidence and severity. Reduced disease development in uPA-deficient and uPAR-deficient mice was not due to an altered adaptive immune response to the CIA challenge. Reciprocal bone marrow transplant studies indicated that uPAR-driven CIA was due to expression by hematopoietic-derived cells, as mice with uPAR-deficient bone marrow challenged with CIA developed significantly reduced macroscopic and histological joint disease as compared with mice with uPAR expression limited to non-hematopoietic-derived cells. These findings indicate a fundamental role for uPAR-expressing hematopoietic cells in driving arthritis incidence and progression. Thus, uPA/uPAR-mediated cell surface proteolysis and/or uPAR-mediated signaling events promote inflammatory joint disease, indicating that disruption of this key proteolytic/signaling system may provide a novel therapeutic strategy to limit clinical arthritis.

N‑trans‑ρ‑caffeoyl tyramine isolated from Tribulus terrestris exerts anti‑inflammatory effects in lipopolysaccharide‑stimulated RAW 264.7 cells

Inflammation is induced by the expression of cyclooxygenase‑2 (COX‑2), which is an important mediator of chronic inflammatory diseases, such as rheumatoid arthritis, asthma and inflammatory bowel disease. Tribulus terrestris (T. terrestris) is known to have a beneficial effect on inflammatory diseases. In this study, we investigated the effects of N‑trans‑ρ‑caffeoyl tyramine (CT) isolated from T. terrestris on the production of nitric oxide (NO), and the expression of pro‑inflammatory cytokines and COX‑2 in lipopolysaccharide (LPS)‑stimulated RAW 264.7 cells. We also aimed to elucidate the molecular mechanisms involved. We found that the ethanolic extract of T. terrestris (EETT) and CT inhibited the production of NO, tumor necrosis factor‑α (TNF‑α), interleukin (IL)‑6 and IL‑10 in the LPS‑stimulated RAW 264.7 cells in a dose‑dependent manner. They were determined by reverse transcription-polymerase chain reaction (RT-PCR) and enzyme-linked immunosorbent assay (ELISA). In addition, CT markedly suppressed the expression of COX‑2 and the production of prostaglandin E2 (PGE2) in response to LPS stimulation. Furthermore, CT markedly decreased p‑c‑Jun N‑terminal kinase (p‑JNK) protein expression in LPS‑stimulated RAW 264.7 cells. COX-2 and p-JNK were measured by western blot analysis. Taken together, these findings indicate that CT isolated from T. terrestris is a novel and potent modulator of inflammatory responses. Thus, it may prove benefiical to further evaluate CT as a possible treatment for chronic inflammatory diseases.

Improved serological detection of rheumatoid arthritis: a highly antigenic mimotope of carbonic anhydrase III selected in a murine model by phage display

INTRODUCTION

Rheumatoid arthritis (RA) is a chronic inflammatory autoimmune disease that affects around 1% of the human population worldwide. RA diagnosis can be difficult as there is no definitive test for its detection. Therefore, the aim of this study was to identify biomarkers that could be used for RA diagnosis.

METHODS

Sera from a collagen-induced arthritis mouse model were used to select potential biomarkers for RA diagnosis by phage display technology. In silico and in vitro analyses were performed to characterize and validate the selected peptides. Samples were classified into three groups: RA; two other immune-mediated rheumatic diseases (systemic lupus erythematosus (SLE) and ankylosing spondylitis (AS)); and healthy controls (HC). Enzyme-linked immunosorbent assay (ELISA) was carried out to determine antibody levels, and diagnostic parameters were determined by constructing receiver operating characteristic curves. Mass spectrometry and Western blot were performed to identify the putative autoantigen that was mimicked by a highly reactive mimotope.

RESULTS

After three rounds of selection, 14 clones were obtained and tested for immunoreactivity analysis against sera from RA and HC groups. The phage-fused peptide with the highest immunoreactivity (M12) was synthesized, and was able to efficiently discriminate RA patients from SLE, AS and HCs (p < 0.0001) by ELISA. The specificity and sensitivity of anti-M12 antibodies for RA diagnosis were 91 % and 84.3 %, respectively. The M12 peptide was identified as one that mimics a predicted antigenic site of the carbonic anhydrase III (CAIII) protein, a ubiquitous biomarker that has been identified in patients with other diseases.

CONCLUSION

M12 is the first peptide associated with the CAIII protein that may be used as an antigen for antibody detection to aid in RA diagnosis with high sensitivity and specificity.

A multiplex immunoassay method for simultaneous quantification of iron, vitamin A and inflammation status markers

Deficiencies of vitamin A and iron affect a significant portion of the world's population, and efforts to characterize patterns of these deficiencies are hampered by a lack of measurement tools appropriate for large-scale population-based surveys. Vitamin A and iron are not easily measured directly, so reliable proxy markers for deficiency status have been identified and adopted. Measurement of inflammatory markers is necessary to interpret vitamin A and iron status markers, because circulating levels are altered by inflammation. We developed a multiplex immunoassay method for simultaneous measurement of five markers relevant to assessing inflammation, vitamin A and iron status: α-1-acid glycoprotein, C-reactive protein, retinol binding protein 4, ferritin and soluble transferrin receptor. Serum and plasma specimens were used to optimize the assay protocol. To evaluate assay performance, plasma from 72 volunteers was assayed using the multiplex technique and compared to conventional immunoassay methods for each of the five markers. Results of the new and conventional assay methods were highly correlated (Pearson Correlations of 0.606 to 0.991, p<.0001). Inter-assay imprecision for the multiplex panel varied from 1% to 8%, and all samples fell within the limits of quantification for all assays at a single dilution. Absolute values given by the multiplex and conventional assays differed, indicating a need for further work to devise a new standard curve. This multiplexed micronutrient immunoassay technique has excellent potential as a cost effective tool for use in large-scale deficiency assessment efforts.

Inhibition of P2X4 suppresses joint inflammation and damage in collagen-induced arthritis

Recent data have shown that the purinergic receptor P2X4 plays key roles in inflammatory responses. We evaluated whether P2X4 inhibition could affect the development of arthritis and autoimmunity in collagen-induced arthritis (CIA) model. P2X4 antisense oligonucleotide (asODN) was injected intravenously via tail vein into the CIA mice to selectively inhibit P2X4 expression daily for 14 days. P2X4 asODN treatment reduced the clinical score of CIA in mice. P2X4 asODN also decreased the levels of serum IL-1β, TNF-α, IL-6, and IL-17. P2X4 asODN treatment significantly inhibited synovial inflammation and joint destruction. P2X4 asODN treatment also suppressed the NLR family, pyrin domain containing 1 (NLRP1) inflammasome activation in CIA mice and synovial cells of human rheumatoid arthritis. These data show that P2X4 asODN confers a therapeutic benefit on CIA. Inhibition of the NLRP1 inflammasome signaling pathway is the underlying mechanism of action.

Protection against Chikungunya virus induced arthralgia following prophylactic treatment with adenovirus vectored interferon (mDEF201)

Recent outbreaks of Chikungunya virus (CHIKV) infection have resulted in millions of cases of disease with significant morbidity. No approved antiviral treatments exist for the prevention or treatment of this viral disease. Infection with CHIKV results in a high rate of symptomatic disease that primarily includes a debilitating arthralgia. To model this cardinal disease manifestation, adult DBA/1J mice were challenged with CHIKV by footpad injection. Viremia and hind limb virus titers increased ∼100-fold while spleen virus increased >1000-fold within 1day post-virus infection (dpi). Footpad swelling was measured over a 10-day period, with peak swelling observed between 6 and 7dpi. Histology of the hind leg at the site of virus challenge showed evidence of myositis and synovitis starting on 5dpi. Cytokine profiling of the hind limb at the site of inoculation revealed a biphasic inflammatory response represented by an increase in IL-6, MCP-1, IFN-γ, MIP-1α, RANTES, and IL-17. To investigate the prophylactic capacity of IFN, mice were treated with mDEF201, an adenovirus-vectored IFN-α. Intranasal administration of a single 10(7)pfu/ml dose of mDEF201 administered 21days to 24h prior to infection, significantly reduced footpad swelling, virus titers in the hind leg and spleen, and several inflammatory cytokines. Efficacy was not observed when treatment was initiated 24h after virus challenge. This arthralgia model of CHIKV recapitulates relevant disease features commonly observed in human disease making it applicable to preclinical testing of therapies that target both viral replication and the associated joint disease.

Therapeutic targets for rheumatoid arthritis: Progress and promises

Recent therapeutic advancements in understanding of molecular and cellular mechanisms of rheumatoid arthritis (RA) have highlighted the strategies that aim to inhibit the harmful effects of up-regulated cytokines or other inflammatory mediators and to inhibit their associated signaling events. The utility of cytokine as therapeutic targets in RA has been unequivocally demonstrated by the success of tumor necrosis factor (TNF)-α blockade in clinical practice. Partial and non-responses to TNF-α blocking agents, however, together with the increasing clinical drive to remission induction, requires that further therapeutic targets be identified. Numerous proinflammatory mediators with their associated cell signaling events have now been demonstrated in RA, including interleukin (IL)-1 and IL-12 superfamilies. Continued efforts are ongoing to target IL-6, IL-15 and IL-17 in clinical trials with promising data emerging. In the present review, we focus on IL-7, IL-18, IL-32 and IL-10 family of cytokines (IL-19, IL-20 and IL-22) as they are implicated in contributing to the pathogenesis of RA, which could be targeted and offer new therapeutic options for RA therapy. Recent evidences also suggest that multiligand receptor for advanced glycation end products (RAGE), several adipokines and various components of immune system play a critical role in the pathophysiology of RA; therefore we have also highlighted them as therapeutic targets for RA therapy. Components of subcellular pathways, involve in nuclear transcription factor (NF)-κB, mitogen-activated protein kinases (MAPKs) and the Janus kinase-signal transducer and activator of transcription (JAK-STAT) pathway have also been discussed and offer several novel potential therapeutic opportunities for RA.

A trifluoromethyl analogue of celecoxib exerts beneficial effects in neuroinflammation

Celecoxib is a selective cyclooxygenase-2 (COX2) inhibitor. We have previously shown that celecoxib inhibits experimental autoimmune encephalomyelitis (EAE) in COX-2-deficient mice, suggestive for a mode of action involving COX2-independent pathways. In the present study, we tested the effect of a trifluoromethyl analogue of celecoxib (TFM-C) with 205-fold lower COX-2 inhibitory activity in two models of neuroinflammation, i.e. cerebellar organotypic cultures challenged with LPS and the EAE mouse model for multiple sclerosis. TFM-C inhibited secretion of IL-1β, IL-12 and IL-17, enhanced that of TNF-α and RANTES, reduced neuronal axonal damage and protected from oxidative stress in the organotypic model. TFM-C blocked TNF-α release in microglial cells through a process involving intracellular retention, but induced TNF-α secretion in primary astrocyte cultures. Finally, we demonstrate that TFM-C and celecoxib ameliorated EAE with equal potency. This coincided with reduced secretion of IL-17 and IFN-γ by MOG-reactive T-cells and of IL-23 and inflammatory cytokines by bone marrow-derived dendritic cells. Our study reveals that non-coxib analogues of celecoxib may have translational value in the treatment of neuro-inflammatory conditions.

11β-Hydroxysteroid dehydrogenase 1 inhibition attenuates collagen-induced arthritis

11β-Hydroxysteroid dehydrogenase 1 (11β-HSD1) plays an important role in inflammation. However, the role of 11β-HSD1 in rheumatoid arthritis (RA) remains unknown. The purpose of this study was to evaluate the therapeutic effects of a selective 11β-HSD1 inhibitor BVT-2733 in collagen-induced arthritis (CIA) and its underlying mechanisms. CIA mice were treated with BVT-2733 (100 mg/kg, orally) or vehicle twice daily for 2 weeks. Arthritis score and joint histology were investigated. The levels of pro-inflammatory cytokines as well as anti-type II collagen antibody (anti-CII) were detected by ELISA. Western blot analysis was used to assess the activation of NF-κB and NLRP1 inflammasome in joint tissues and in human RA synovial cells. BVT-2733 treatment attenuated the arthritis severity and anti-CII level in CIA mice. BVT-2733 also decreased the levels of serum TNF-α, IL-1β, IL-6 and IL-17. BVT-2733 treatment also significantly reduced synovial inflammation and joint destruction. NF-κB activation and NLRP1 inflammasome assembly were also inhibited in arthritic joints and human RA synovial cells. In conclusion, BVT-2733 exhibits an anti-inflammatory effect on CIA. This protective effect is, at least partly, mediated by inhibition of the NF-κB and NLRP1 inflammasome signaling pathways. 11β-HSD1 inhibition may represent a potential therapeutic target for RA patients.

Molecular mechanism of the inhibition effect of Celecoxib on corneal collagen degradation in three dimensions

AIM

To clarify the molecular mechanism of Celecoxib on corneal collagen degradation and corneal ulcer.

METHODS

Rabbit corneal fibroblasts were harvested and suspended in serum-free MEM. Type I collagen, DMEM, collagen reconstitution buffer and corneal fibroblast suspension were mixed on ice. The resultant mixture solidify in an incubator, after which test reagents and plasminogen was overlaid and the cultures were returned to the incubator. The supernatants from collagen gel incubations were collected and the amount of hydroxyproline in the hydrolysate was measured. Immunoblot analysis of MMP1, 3 and TIMP1, 2 was performed. MMP2, 9 was detected by the method of Gelatin zymography. Cytotoxicity Assay was measured.

RESULTS

Celecoxib inhibited corneal collagen degradation in a dose and time manner; Celecoxib inhibited the IL-1ß induced increases in proMMP1, 2, 3, 9 and active MMP1, 2, 3, 9 in a concentration-depended manner. Celecoxib can also inhibit the IL-1ß induced increases in the TIMP1, 2.

CONCLUSION

Celecoxib can inhibit corneal collagen degradation induced by IL-1β, this effect is the consequence of the reduction of MMP1, 2, 3, 9 and TIMP1, 2. The results of the present study provide new insight into Celecoxib in corneal ulcer treatment.