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The development of osteoarthritis (OA) has recently been implicated as a result of immune-mediated damage of chondrocytes and their supporting matrixes. Pro-inflammatory cytokines like interleukin (IL)-1 and tumor necrosis factor alpha (TNF-alpha) play pivotal roles in immunopathogenesis of OA. Because vitamins preserving anti-oxidative effects are suggested to provide protection in OA patients from joint damage, in the present study, we examined the effects and mechanisms of all-trans retinoic acid (t-RA) in suppressing pro-inflammatory cytokine-induced matrix metalloproteinases (MMPs) production in human chondrocytes. Chondrocytes were prepared from cartilage specimens of OA patients receiving total hip or total knee replacement. The protein concentration was measured by ELISA, the mRNA expression by reverse transcriptase-polymerase chain reaction, the protein expression by Western blotting, the transcription factor DNA-binding activity by electrophoretic mobility shift assay and the protein kinase activity by kinase assay. We showed that both MMP-1 and MMP-13 mRNA expression, protein production and enzyme activity induced by either IL-1 or TNF-alpha were suppressed by t-RA or different retinoid derivatives. The molecular investigation revealed that the t-RA-mediated suppression was likely through blocking p38 kinase and c-Jun N-terminal kinase-activator protein-1 signaling pathways. In contrast, t-RA had no effect on extracellular signal-regulated kinase activity, nuclear factor (kappa)B (NF-(kappa)B) DNA-binding activity and I(kappa)B(alpha) degradation. Furthermore, we showed that t-RA could reduce IL-1-induced TNF-alpha production in chondrocytes. Our results suggest that vitamin A may protect OA patients from pro-inflammatory cytokine-mediated damage of chondrocytes and their supporting matrixes.

Dengue viruses (DV) infection is an important public health issue all over the world. Although the pathogenesis remains unclear, the overwhelmingly triggered immune responses have been consistently observed. Recently, we and other researchers demonstrated that the natural hosts for DV are dendritic cells (DC), the primary sentinels of immune system. In light of the significance of T cells in dengue virus pathogenesis, here, we examine the possible consequences of DC-T cell interaction that is supposed to be happening in lymphoid tissues after infection. We showed that DV-infected DC induced the interacting T cells to proliferate, to produce interleukin-2 as well as to express activation markers on cell surface. Compared to mock-infected DC, the infection of DC by DV also induced T cells to produce interleukin-4, interleukin-10 and interferon-gamma, a cytokine pattern suggesting Th0 phenotype. Such an effect was either totally abolished or greatly reduced when DV were pre-inactivated with heat or ultraviolet before infection. In addition, we demonstrated that such a Th0 phenotype shift of T cells was affected neither by different dosages of viruses that infected DC nor by different durations of DC-T cell interaction. Our results provide a basic support for clinical observations and may be of help in understanding the pathogenesis of DV infection.

Aim: Mood disorders are a serious issue for patients with rheumatoid arthritis (RA) because poor mental health can exacerbate the disease course. This study aimed to identify the effect of proinflammatory cytokines on the mood of patients with RA. Methods: This study was conducted at a rheumatology clinic in Northern Taiwan. In total, 113 patients with RA and 42 healthy controls were assessed for anxiety and depression symptoms using Hospital Anxiety and Depression Scale (HADS). RA was assessed using the Disease Activity Score of 28 joints (DAS28). Serum proinflammatory cytokine levels, including interleukin (IL)‐1β, IL‐6, IL‐17 and tumor necrosis factor alpha (TNF‐α) were measured and compared between different patient groups according to disease activity and pain level. Results: Serum IL‐1β, IL‐6, IL‐17 and TNF‐α levels were significantly higher in patients with RA than in healthy controls, as were the mean anxiety and depression subscale scores. In patients with RA who had different disease activities, pain severity correlated with both anxiety and depression symptoms. When HADS scores were analyzed according to pain levels, age was correlated with depression in the severe pain group. In the mild pain group, patients with higher IL‐6 or higher IL‐17 had a higher risk of depression. There was no correlation between mood symptoms and cytokine levels in healthy controls. Conclusion: Elevated serum IL‐6 and IL‐17 levels in patients with RA induce arthritis and cause mood symptoms, especially depression symptoms. [ABSTRACT FROM AUTHOR]

This study aims to investigate the effects and mechanisms of all-trans retinoic acid (t-RA) on interleukin(IL)-1-induced production of several inflammatory mediators in human chondrocytes. The cartilage from OA patients receiving total knee or total hip replacement was obtained and chondrocytes were prepared. Chemokine concentrations were measured by ELISA. The expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) was determined by Western blotting and/or RT/PCR. Nitrite levels were measured by Griess assays. The DNA-binding activity and transcriptional activity of activator protein-1 (AP-1) were measured by electrophoresis mobility shift assay and luciferase assay. We showed that t-RA suppressed IL-1-induced release of chemokines, including regulated upon activation, normal T cell expressed and secreted (RANTES), monocyte chemoattractant protein 2 (MCP-2), macrophage inflammatory protein-1alpha (MIP-1α) and MIP-1β. Four different retinoid derivatives all preserved inhibitory effects albeit the potency was different. t-RA potently suppressed IL-1-induced expression of iNOS and COX-2 and production of nitric oxide and prostaglandin E2. In consistent with the results in primary chondrocytes, t-RA down-regulated IL-1-induced AP-1 DNA binding activity and transcriptional activity in a human fibroblast-like (commercially labeled as chondrocyte) cell line. By examining the effect of a c-jun N-terminal kinase (JNK) specific inhibitor, we showed that the suppression of JNK-AP-1 signaling was enough to inhibit IL-1-induced production of chemokines and activation of iNOS and COX-2 pathways. Collectively, our results raise a therapeutic option that intra-articular administration of retinoid derivatives at 10-1000 nanomolar concentrations may be effective to suppress the progression of inflammatory OA. [ABSTRACT FROM AUTHOR]

Background/purpose: Antibodies against type II collagen (anti-CII) are arthritogenic and central to the initiation of the disease. An animal model of collagen type II-specific monoclonal antibody-induced arthritis (CAIA) has been used for the evaluation of various therapeutic effects in rheumatoid arthritis (RA). We aimed to measure the expression of matrix metalloproteinase (MMP)-9 (gelatinase B), tumor necrosis factor-alpha (TNF-alpha) and interleukin-1beta (IL-1beta) in the acute and chronic stages of the CAIA model for application as a therapeutic marker.Methods: A commercially available antibody cocktail containing four monoclonal anti-type II collagen antibodies were injected into 6 to 8-week-old male BALB/c mice (n=20) and 50 microL lipopolysaccharide was injected 3 days later. The clinical manifestations of RA were recorded and scored at 10 days (acute stage) and 21 days (chronic stage). Then the mice were sacrificed for histologic analysis of the inflamed footpad and gene expression of IL-1beta, TNF-alpha and MMP-9 by ELISA and quantitative polymerase chain reaction amplification.Results: Marked inflammation was found in the limb joints of mice at 10 days. Both IL-1beta and MMP-9 expression played a central role in the inflammatory reaction in the acute stage. The expression level of MMP-9 mRNA remained high in the chronic stage of CAIA, but that of IL-1beta mRNA was unexpectedly negligible; the serum level of TNF-alpha in CAIA was undetectable in the acute stage. The expression level of TNF-alpha mRNA was also lower than IL-1beta and MMP-9 in the acute inflammatory stage.Conclusion: The CAIA model is a fast and highly replicable model of RA. MMP-9 and IL-1beta were highly expressed in the acute stage of CAIA. It is suggested the MMP-9 mRNA level is a suitable marker for both acute and chronic stage, whereas IL-1beta is a marker only for the acute stage of the CAIA murine model. [ABSTRACT FROM AUTHOR]

Objective: The activation of T lymphocytes contributes to the inflammatory process of atherosclerosis. Here we examined the effects of carvedilol, a new β-blocker containing an antioxidative property, on the activation of T cells. Methods: Human peripheral blood T cells were negatively selected from whole blood. Cytokines were measured by ELISA. The NF-κB and related protein activity was determined by electrophoretic mobility shift assays, Western blotting, kinase assays and transfection assays. Results: Carvedilol was nontoxic at concentrations ≦10 μM, however, higher dosages (⩾20 μM) induced T cell apoptosis. We demonstrated that carvedilol inhibited cytokine production from various stimuli-activated T cells. Carvedilol also suppressed the expression of T cell activation markers, including CD25, CD69 and CD71. Molecular investigation indicated that carvedilol specifically downregulated NF-κB but not activator protein 1 DNA-binding activity in activated T cells. The inhibitory effect was likely due to its antioxidative property. Meanwhile, carvedilol prevented stimuli-induced IκBα degradation. Such an effect was mediated through the inhibition of IκBα kinase activity. The inhibitory specificity on NF-κB by carvedilol was also demonstrated in transfection assays. Conclusions: Our results demonstrated a novel therapeutic mechanism of carvedilol in atherosclerosis, namely the inhibition of T cell activation via downregulating NF-κB activity. [Copyright &y& Elsevier]

The activation of T lymphocytes contributes to inflammatory process of cardiovascular and cerebrovascular diseases. We investigated the effects of the extract of Ginkgo biloba (EGb), an ancient plant preserving antioxidant property, on phorbol 12-myristate 13-acetate+ionomycin or anti-CD3+anti-CD28 monoclonal antibodies-activated T cells. Human peripheral blood T cells were negatively selected from whole blood. Cytokines were measured by ELISA, cell surface markers by flow cytometry and the activities of transcription factors and kinases were determined by electrophoresis mobility shift assays, kinase assays and transfection assays. We showed that EGb inhibited several cytokines, including tumor necrosis factor-alpha, interleukin (IL)-2, IL-4 and interferon-gamma production from activated T cells. Electrophoresis mobility shift assay analysis indicated that EGb down-regulated activator protein-1 (AP-1) but not nuclear factor kappa B DNA-binding activity. In addition, EGb inhibited c-jun N-terminal kinase but not extracellular signal regulated protein kinase activity. The inhibitory specificity on AP-1 by EGb was also demonstrated in transfection assays. The inhibition of AP-1 signaling pathway in T cells by EGb provides a support for its efficacy in cardiovascular and cerebrovascular diseases and raises a therapeutic potential for this drug in activated T cell-mediated pathologies. [Copyright &y& Elsevier]