The effect of a T cell-specific NF-kappa B inhibitor on in vitro cytokine production and collagen-induced arthritis

Targeting the chromatin binding of exportin-1 disrupts NFAT and T cell activation

Exportin-1 (XPO1/CRM1) plays a central role in the nuclear-to-cytoplasmic transport of hundreds of proteins and contributes to other cellular processes, such as centrosome duplication. Small molecules targeting XPO1 induce cytotoxicity, and selinexor was approved by the Food and Drug Administration in 2019 as a cancer chemotherapy for relapsed multiple myeloma. Here, we describe a cell-type-dependent chromatin-binding function for XPO1 that is essential for the chromatin occupancy of NFAT transcription factors and thus the appropriate activation of T cells. Additionally, we establish a class of XPO1-targeting small molecules capable of disrupting the chromatin binding of XPO1 without perturbing nuclear export or inducing cytotoxicity. This work defines a broad transcription regulatory role for XPO1 that is essential for T cell activation as well as a new class of XPO1 modulators to enable therapeutic targeting of XPO1 beyond oncology including in T cell-driven autoimmune disorders.

Molecular Basic of Pharmacotherapy of Cytokine Imbalance as a Component of Intervertebral Disc Degeneration Treatment

Intervertebral disc degeneration (IDD) and associated conditions are an important problem in modern medicine. The onset of IDD may be in childhood and adolescence in patients with a genetic predisposition. With age, IDD progresses, leading to spondylosis, spondylarthrosis, herniated disc, spinal canal stenosis. One of the leading mechanisms in the development of IDD and chronic back pain is an imbalance between pro-inflammatory and anti-inflammatory cytokines. However, classical therapeutic strategies for correcting cytokine imbalance in IDD do not give the expected response in more than half of the cases. The purpose of this review is to update knowledge about new and promising therapeutic strategies based on the correction of the molecular mechanisms of cytokine imbalance in patients with IDD. This review demonstrates that knowledge of the molecular mechanisms of the imbalance between pro-inflammatory and anti-inflammatory cytokines may be a new key to finding more effective drugs for the treatment of IDD in the setting of acute and chronic inflammation.

RIPK1-Associated Inborn Errors of Innate Immunity

RIPK1 (receptor-interacting serine/threonine-protein kinase 1) is a key molecule for mediating apoptosis, necroptosis, and inflammatory pathways downstream of death receptors (DRs) and pattern recognition receptors (PRRs). RIPK1 functions are regulated by multiple post-translational modifications (PTMs), including ubiquitination, phosphorylation, and the caspase-8-mediated cleavage. Dysregulation of these modifications leads to an immune deficiency or a hyperinflammatory disease in humans. Over the last decades, numerous studies on the RIPK1 function in model organisms have provided insights into the molecular mechanisms of RIPK1 role in the maintenance of immune homeostasis. However, the physiological role of RIPK1 in the regulation of cell survival and cell death signaling in humans remained elusive. Recently, RIPK1 loss-of-function (LoF) mutations and cleavage-deficient mutations have been identified in humans. This review discusses the molecular pathogenesis of RIPK1-deficiency and cleavage-resistant RIPK1 induced autoinflammatory (CRIA) disorders and summarizes the clinical manifestations of respective diseases to help with the identification of new patients.

LPS induces fibroblast-like synoviocytes RSC-364 cells to pyroptosis through NF-κB mediated dual signalling pathway

Rheumatoid arthritis (RA) is a chronic, progressive, and systemic inflammatory joint disease characterized by synovial inflammation and joint damage. Abnormal activation of fibroblast-like synoviocytes is an initial event of synovial inflammation and joint damage, which can significantly aggravate the progression of RA. Clinical studies have shown that synovitis may be associated with pyroptosis. Therefore, this study is mainly aim for exploring the underlying mechanisms of relationship between inflammation and pyroptosis during synovitis. A cell model of synovitis was constructed by stimulating synovial fibroblasts RSC-364 cells with lipopolysaccharide (LPS). In vitro, we found that LPS can induce pyroptosis of synovial fibroblasts through NOD-like receptor pyrin domain-3/caspase-1/gasdermin D and caspase-3/gasdermin E two signaling pathways, and these two signaling pathways can promote each other. In addition, NF-κB signaling pathway, as the upstream of these two pathways, is involved in regulating the pyroptosis of synovial fibroblast. These results suggest that pyroptosis may be triggered during the occurrence of RA. We hope to provide a new perspective for the study of RA and a new therapeutic target for clinical treatment of RA.

Research developments in the syntheses, anti-inflammatory activities and structure-activity relationships of pyrimidines

Pyrimidines are aromatic heterocyclic compounds that contain two nitrogen atoms at positions 1 and 3 of the six-membered ring. Numerous natural and synthetic pyrimidines are known to exist. They display a range of pharmacological effects including antioxidants, antibacterial, antiviral, antifungal, antituberculosis, and anti-inflammatory. This review sums up recent developments in the synthesis, anti-inflammatory effects, and structure-activity relationships (SARs) of pyrimidine derivatives. Numerous methods for the synthesis of pyrimidines are described. Anti-inflammatory effects of pyrimidines are attributed to their inhibitory response versus the expression and activities of certain vital inflammatory mediators namely prostaglandin E2, inducible nitric oxide synthase, tumor necrosis factor-α, nuclear factor κB, leukotrienes, and some interleukins. Literature studies reveal that a large number of pyrimidines exhibit potent anti-inflammatory effects. SARs of numerous pyrimidines have been discussed in detail. Several possible research guidelines and suggestions for the development of new pyrimidines as anti-inflammatory agents are also given. Detailed SAR analysis and prospects together provide clues for the synthesis of novel pyrimidine analogs possessing enhanced anti-inflammatory activities with minimum toxicity.

In vivo, Extract from Withania somnifera Root Ameliorates Arthritis via Regulation of Key Immune Mediators of Inflammation in Experimental Model of Arthritis

BACKGROUND

Rheumatoid Arthritis (RA) is a devastating disease characterized by continual addition of leukocytes and T cells within the articular cavity causing inflammation and cartilage destruction. Withania somnifera is one of the most precious medicinal herbs, reported to have antioxidant, anti-inflammatory, and immunomodulatory properties.

OBJECTIVE

The purpose of this study was to evaluate anti-inflammatory activity of aqueous extract of Withania somnifera roots (WSAq) in Collagen Induced Arthritic (CIA) rats.

METHODS

To achieve this, we assessed the level of inflammatory cytokines such as Tumor Necrosis Factor (TNF)-α, IL-1β, IL-6 and IL-10 in CIA rats. Further, transcription factor, oxidative stress parameters and CD+8 expressions were also analyzed in CIA rats.

RESULTS

Arthritic rats showed a greater increase in the levels of pro inflammatory cytokines such as TNF-α, IL-1β, IL-6, transcription factor NF-κB and a decrease in IL-10 concentration than controls rats. Oral administration of WSAq at a dose of 300mg/kg.wt. (WSAq300) appreciably attenuated the production of these pro inflammatory cytokines. This anti-inflammatory activity of WSAq300 might be partly mediated through an increase in the secretion of IL-10 and inhibition of NF-κB activity. Further, arthritic rats also show increased oxidative stress as compared to control rats. This increased oxidative stress in the arthritic rats appears to be the outcome of both an activated pro-oxidant and a poor antioxidant defense system. Treatment with WSAq300 strongly ameliorates all these ROS parameters significantly to near normal. Additional, metalloproteinase MMP-8 levels were also measured and found to be increased in CIA rats, which after treatment with WSAq300 came down to near normal.

CONCLUSION

From the above results, it can be concluded that the use of WSAq300 may be a valuable supplement which can improve human arthritis.

Restoring the IL-1β/NF-κB-induced impaired chondrogenesis by diallyl disulfide in human adipose-derived mesenchymal stem cells via attenuation of reactive oxygen species and elevation of antioxidant enzymes

Strategies based on mesenchymal stem cell (MSC) therapy for restoring injured articular cartilage are not effective enough in osteoarthritis (OA). Due to the enhanced inflammation and oxidative stress in OA microenvironment, differentiation of MSCs into chondrocytes would be impaired. This study aims to explore the effects of diallyl disulfide (DADS) on IL-1β-mediated inflammation and oxidative stress in human adipose derived mesenchymal stem cells (hADSCs) during chondrogenesis. MTT assay was employed to examine the effects of various concentrations of DADS on the viability of hADSCs at different time scales to obtain non-cytotoxic concentration range of DADS. The effects of DADS on IL-1β-induced intracellular ROS generation and lipid peroxidation were evaluated in hADSCs. Western blotting was used to analyze the protein expression levels of IκBα (np), IκBα (p), NF-κB (np) and NF-κB (p). Furthermore, the gene expression levels of antioxidant enzymes in hADSCs and chondrogenic markers at days 7, 14 and 21 of differentiation were measured using qRT-PCR. The results showed that addition of DADS significantly enhanced the mRNA expression levels of antioxidant enzymes as well as reduced ROS elevation, lipid peroxidation, IκBα activation and NF-κB nuclear translocation in hADSCs treated with IL-1β. In addition, DADS could significantly increase the expression levels of IL-1β-induced impaired chondrogenic marker genes in differentiated hADSCs. Treatment with DADS may provide an effective approach to prevent the pro-inflammatory cytokines and oxidative stress as catabolic causes of chondrocyte cell death and enhance the protective anabolic effects by promoting chondrogenesis associated gene expressions in hADSCs exposed to OA condition.

p62/sequestosome 1 deficiency accelerates osteoclastogenesis in vitro and leads to Paget's disease-like bone phenotypes in mice

The sequestosome 1 gene encodes the p62 protein and is the major genetic risk factor associated with Paget's disease of bone. In 2004, p62 was reported to up-regulate osteoclast differentiation by activating the transcription factors Nfatc1 and NF-κB. Here, we characterized the osteoclastogenic potential of murine p62^-/--derived cells compared with WT cells. Our data confirmed previous findings indicating that p62 is induced during murine osteoclast differentiation. Surprisingly, an indispensable role for p62 in in vitro osteoclast differentiation was not reproducible because p62-deficient osteoclasts exhibited robust activation of Nfatc1, NF-κB, and osteoclast marker enzymes. Thus, we concluded that in vitro osteoclast differentiation is not negatively influenced by knocking out p62. On the contrary, our results revealed that p62 deficiency accelerates osteoclastogenesis. Differentiation potential, multinucleation status, and soluble receptor activator of NF-κB ligand (sRANKL) sensitivity were significantly elevated in p62-deficient, murine bone marrow-derived stem cells. Moreover, femur ultrastructures visualized by micro-computed tomography revealed pronounced accumulation of adipocytes and trabecular bone material in distal femora of obese p62^-/- mice. Increased tartrate-resistant acid phosphatase activity, along with increased trabecular bone and accumulation of adipocytes, was confirmed in both paraffin-embedded decalcified and methyl methacrylate-embedded nondecalcified bones from p62^-/- mice. Of note, Paget's disease-like osteolytic lesions and increased levels of the bone turnover markers CTX-I and PINP were also observed in the p62^-/- mice. Our results indicate that p62 predominantly suppresses murine in vitro osteoclast differentiation and highlight previously undetected Paget's disease-like phenotypes in p62^-/- mice in vivo.

Aloin Suppresses Lipopolysaccharide-Induced Inflammatory Response and Apoptosis by Inhibiting the Activation of NF-κB

Numerous herbal-derived natural products are excellent anti-inflammatory agents. Several studies have reported that aloin, the major anthraquinone glycoside obtained from the Aloe species, exhibits anti-inflammatory activity. However, the molecular mechanism of this activity is not well understood. In this report, we found that aloin suppresses lipopolysaccharide-induced pro-inflammatory cytokine secretion and nitric oxide production, and downregulates the expression of tumor necrosis factor alpha (TNF-α), interleukin 6 (IL-6), inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2). Aloin inhibits the phosphorylation and acetylation of the NF-κB p65 subunit by suppressing the upstream kinases p38 and Msk1, preventing LPS-induced p65 translocation to the nucleus. We have also shown that aloin inhibits LPS-induced caspase-3 activation and apoptotic cell death. Collectively, these findings suggest that aloin effectively suppresses the inflammatory response, primarily through the inhibition of NF-κB signaling.

The sneaking ligand approach for cell type-specific modulation of intracellular signalling pathways

Small molecules interfering with intracellular signalling pathways are used in the treatment of multiple diseases including RA. However, small molecules usually affect signalling in most cell types, not only in those which need to be targeted. This general inhibition of signalling pathways causes often adverse effects, which could be avoided by cell type-specific inhibitors. For cell-type specific modulation of signal transduction, we developed the sneaking ligand fusion proteins (SLFPs). SLFPs contain three domains: (1) the binding domain mediating cell type-specific targeting and endocytosis; (2) the endosomal release sequence releasing the effector domain into the cytoplasm; (3) the effector domain modulating signalling. Using our SLFP NF-kappaB inhibitor termed SLC1 we demonstrated that cell-type-specific modulation of intracellular signalling pathways is feasible, that endothelial NF-kappaB activation is critical for arthritis and peritonitis and that SLFPs help to identify disease-relevant pathways in defined cell types. Hence, SLFPs may improve risk-benefit ratios of therapeutic interventions.

Killer cells in atherosclerosis

Cytotoxic lymphocytes (killer cells) play a critical role in host defence mechanisms, protecting against infections and in tumour surveillance. They can also exert detrimental effects in chronic inflammatory disorders and in autoimmune diseases. Tissue cell death and necrosis are prominent features of advanced atherosclerotic lesions including vulnerable/unstable lesions which are largely responsible for most heart attacks and strokes. Evidence for accumulation of killer cells in both human and mouse lesions together with their cytotoxic potential strongly suggest that these cells contribute to cell death and necrosis in lesions leading to vulnerable plaque development and potentially plaque rupture. Killer cells can be divided into two groups, adaptive and innate immune cells depending on whether they require antigen presentation for activation. Activated killer cells detect damaged or stressed cells and kill by cytotoxic mechanisms that include perforin, granzymes, TRAIL or FasL and in some cases TNF-α. In this review, we examine current knowledge on killer cells in atherosclerosis, including CD8 T cells, CD28- CD4 T cells, natural killer cells and γδ-T cells, mechanisms responsible for their activation, their migration to developing lesions and effector functions. We also discuss pharmacological strategies to prevent their deleterious vascular effects by preventing/limiting their cytotoxic effects within atherosclerotic lesions as well as potential immunomodulatory therapies that might better target lesion-resident killer cells, to minimise any compromise of the immune system, which could result in increased susceptibility to infections and reductions in tumour surveillance.

The Extract of Chrysanthemum zawadskii var. latilobum Ameliorates Collagen-Induced Arthritis in Mice

Chrysanthemum zawadskii var. latilobum (CZ) has been used for beverage or tea and also as folk medicine for the remedy of diverse inflammatory diseases. Nevertheless, the therapeutic effect of CZ on arthritis remains to be unknown. In this paper we aim to investigate the CZ's antiarthritic effect and mechanism of action both in vitro and in vivo. To assess CZ's antiarthritic effect, mouse models of type II collagen-induced arthritis (CIA) were used. Mice were used to gauge clinical arthritis index and histopathological changes. Reverse transcriptase-polymerase chain reaction (RT-PCR), western blotting, electrophoretic mobility shift assay (EMSA), and other biological methods were adopted to measure CZ's effect on arthritis and to understand the veiled mechanism of action. CZ greatly suppressed CIA, histopathological score, bone erosion, and osteoclast differentiation. Mechanistically, CZ inhibited the production of various inflammatory and arthritic mediators like inflammatory cytokines, matrix metalloproteinases (MMPs), and chemokines. Of note, CZ significantly suppressed the activation of the NF-κB pathway in vivo. CZ exerted an antiarthritic effect in CIA mice by curbing the production of crucial inflammatory and arthritis mediators. This study warrants further investigation of CZ for the use in human rheumatoid arthritis (RA).

Baicalin attenuates lipopolysaccharide induced inflammation and apoptosis of cow mammary epithelial cells by regulating NF-κB and HSP72

Baicalin is the main ingredient of traditional Chinese herbal medicine, Scutellaria baicalensis, which has been widely used clinically as an anti-inflammatory agent. However, molecular mechanism of action of this drug is not yet clear. In the present study, the protective mechanism of baicalin against lipopolysaccharide (LPS) induced inflammatory injury in cow mammary epithelial cells (CMECs) was explored. For this purpose, in vitro cultured CMECs were treated with baicalin (10μg/mL) and LPS (10μg/mL) for 24 and 12h, respectively, and the cell viability was measured by using cell counting kit-8 (CCK-8). The results revealed that LPS induced inflammatory responses, as p-p65/p65 and p-IκBα/IκBα ratios and TNF-α and IL-1β production was increased in the CMECs. Both Bcl-2/Bax ratio and cell viability were decreased and caspase-3 cleaved following LPS treatment, indicating apoptosis of CMECs. Moreover, both LPS and baicalin increased HSP72 expression of the CMECs. However, cellular inflammatory responses and apoptosis were significantly reduced in baicalin treated CMECs. In conclusion, baicalin ameliorated inflammation and apoptosis of the CMECs induced by LPS via inhibiting NF-κB activation and up regulation of HSP72.

Statins And Biomarkers In Claudicants With Peripheral Arterial Disease: Cross-sectional Study

This exploratory substudy of The Iron (Fe) and Atherosclerosis Study (FeAST) compared baseline inflammatory markers, including cytokines, C-reactive protein (CRP), and ferritin, in subjects with peripheral arterial disease (PAD) taking statins with subjects with PAD who were not taking statins. Inflammatory markers in the serum of 47 subjects with PAD not taking statins and a healthy cohort of 21 medication-free men were compared with 53 PAD subjects taking statins at entry to the FeAST.

Healthy subjects demonstrated lower levels of tumor necrosis factor (TNF)-R1, interleukin-6 (IL-6), and CRP. TNF-α R1 averaged 2.28 ng/mL versus 3.52 ng/mL, p  =  .0025; IL-6 averaged 4.24 pg/mL versus16.61 pg/mL, p  =  .0008; and CRP averaged 0.58 mg/dL versus 0.92 mg/dL, p  =  .0192. A higher level of IL-6 was observed in PAD statin takers versus PAD subjects not taking statins: 19.47 pg/mL versus 13.24 pg/mL, p  =  .0455. As expected, total cholesterol and low-density lipoprotein levels were lower in the statin-treated group, p  =  .0006 and p  =  .0001, respectively. No significant differences in inflammatory cytokines were detected for varying doses of simvastatin. Additionally, no significant differences in inflammatory biomedical markers were found in subjects with PAD alone compared with those with concomitant coronary artery disease (CAD).

Unexpectedly, serum inflammatory cytokine IL-6 levels were significantly higher in PAD subjects receiving statins. There was no difference in measured inflammatory markers in PAD subjects with concomitant CAD.

Hyperoside exerts anti-inflammatory and anti-arthritic effects in LPS-stimulated human fibroblast-like synoviocytes in vitro and in mice with collagen-induced arthritis

AIM

Hyperoside is a flavonol glycoside mainly found in plants of the genera Hypericum and Crataegus, which has shown anti-oxidant, anti-cancer and anti-inflammatory activities. In this study, we investigated the effects of hyperoside on human rheumatoid fibroblast-like synoviocytes (FLSs) in vitro and on mouse collagen-induced arthritis (CIA) in vivo.

METHODS

FLSs were isolated from primary synovial tissues obtained from rheumatoid arthritis (RA) patients and exposed to LPS (1 μg/mL). Cell viability and proliferation were measured with MTT and BrdU assay. Cell migration was assessed using wound-healing assay and Transwell assay. DNA binding of NF-κB was measured using a TransAM-NFkappaB kit. The localization of p65 subunit was detected with immunocytochemistry. CIA was induced in mice by primary immunization with Bovine Type II collagen (CII) emulsified in CFA, followed by a booster injection 3 weeks later. The arthritic mice were treated with hyperoside (25, 50 mg·kg(-1)·d(-1), ip) for 3 weeks, and the joint tissues were harvested for histological analysis.

RESULTS

Hyperoside (10, 50, 100 μmol/L) dose-dependently inhibited LPS-induced proliferation and migration of human RA FLSs in vitro. Furthermore, hyperoside decreased LPS-stimulated production of TNF-α, IL-6, IL-1 and MMP-9 in the cells. Moreover, hyperoside inhibited LPS-induced phosphorylation of p65 and IκBα, and suppressed LPS-induced nuclear translocation of p65 and DNA biding of NF-κB in the cells. Three-week administration of hyperoside significantly decreased the clinical scores, and alleviated synovial hyperplasia, inflammatory cell infiltration and cartilage damage in mice with CIA.

CONCLUSION

Hyperoside inhibits LPS-induced proliferation, migration and inflammatory responses in human RA FLSs in vitro by suppressing activation of the NF-κB signaling pathway, which contributes to the therapeutic effects observed in mice with CIA.

Ginsenoside Ro suppresses interleukin-1β-induced apoptosis and inflammation in rat chondrocytes by inhibiting NF-κB

This study investigated effects of Ginsenoside Ro (Ro) on interleukin-1β (IL-1β)-induced apoptosis and inflammation in rat chondrocytes. The rat chondrocytes were co-treated with IL-1β (10 ng·kg(-1)) and Ro (50, 100 and 200 μmol·L(-1)) for 48 h. Chondrocytes viability was detected by the MTT assay and Annexin V-FITC/PI dual staining assay. Caspase 3 activity was measured by using caspase 3 colorimetric assay kit. Apoptosis related proteins Bax, Bad, Bcl-xL, PCNA, p53 and phospho-p53, along with inflammation related protein MMP 3, MMP 9 and COX-2, and the expression of phospho-NF-κB p65 were assayed by western blotting analyses. Ro could improve IL-1β-induced chondrocytes viability. Ro could suppress IL-1β-induced apoptosis by inhibiting levels of Bax and Bad, decreasing p53 phosphorylation and promoting the expression of Bcl-xL and PCNA. Ro inhibited caspase 3 activity. IL-1β-induced inflammation and matrix degration were also alleviated by Ro with down-regulating the expression of MMP 3, MMP 9 and COX-2. Moreover, Ro inhibited NF-κB p65 phosphorylation induced by IL-1β. In conclusion, these results suggested Ro exerted anti-apoptosis and anti-inflammation in IL-1β-induced rat chondrocytes, which might be related to NF-κB signal pathway. Therefore, we propose that Ro might be a potential novel drug for the treatment of osteoarthritis.

Anti-inflammatory effects of the extract of Gnaphalium affine D. Don in vivo and in vitro

ETHNOPHARMACOLOGICAL RELEVANCE

Gnaphalium affine D. Don (GA) has been traditionally used as a medicinal herb in China for the treatment of many ailments including rheumatoid arthritis. However, the anti-arthritic mechanism of GA has still not been demonstrated. This study aims to reveal the anti-inflammatory activity and anti-arthritic mechanism of ethanol extract of G. affine D. Don.

MATERIALS AND METHODS

Anti-inflammatory potential of GA was analyzed in vivo in carrageenan induced mice paw edema (acute study). Also, in vivo study was applied in collagen-induced arthritis (CIA) rats. In vitro experiments for analyzing the anti-inflammatory potential of GA were performed on rat alveolar macrophages cell line (NR8383). Analysis of nitric oxide release in NR8383 cells was done by Griess reaction. RT-PCR and western blotting experiment was performed to analyze the expression of phosphorylated p65 and IκBα/β-actin in NF-κB pathway. The production of TNF-α, IL-1β, and COX-2 in NR8383 cells were measured by enzyme-linked immunosorbent assay. The chemical profile of GA was analyzed by HPLC-VWD.

RESULTS

GA significantly reduced the paw volume in carrageenan induced rat paw edema rat at different doses (300 and 600 mg/kg), compared with the standard indomethacin treatment. In CIA, GA can obviously ameliorate the inflammatory symptom, including cytokine, histological symptom and paw swelling. In the vitro study, GA was able to reduce the nitric oxide (NO) levels in NR8383 cells that had been stimulated with lipopolysaccharide (LPS). The level of TNF-α, IL-1β, and COX-2 was also decreased with GA treatment in NR8383 cells that had been stimulated with lipopolysaccharide (LPS). Interestingly, GA was found to decrease the level of phosphorylated p65 and IκBα in NR8383 cells. Fifteen compounds were identified by HPLC-VWD with the reference substances and verified by LC-MS.

CONCLUSIONS

The results of the experiment scientifically validated its traditional use in inflammatory conditions.

Increasing expression of substance P and calcitonin gene-related peptide in synovial tissue and fluid contribute to the progress of arthritis in developmental dysplasia of the hip

INTRODUCTION

Developmental dysplasia of the hip (DDH) is a common musculoskeletal disorder that has pain and loss of joint function as major pathological features. In the present study, we explored the mechanisms of possible involvement and regulation of substance P (SP) and calcitonin gene-related peptide (CGRP) in the pathological and inflammatory processes of arthritis in DDH.

METHODS

Blood, synovial tissue and fluid samples were collected from patients diagnosed with different severities of DDH and from patients with femoral neck fracture. Levels of SP, CGRP and inflammatory cytokines in synovium and synovial fluid (SF) in the different groups were evaluated by immunohistochemistry, real-time PCR and enzyme-linked immunosorbent assay (ELISA). Correlations between neuropeptides and inflammatory cytokines in SF were evaluated by partial correlation analysis. The proinflammatory effects of SP and CGRP on synoviocytes obtained from patients with moderate DDH were investigated in vitro by real-time PCR and ELISA. The mechanisms of those effects were evaluated by Western blot analysis and nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB) DNA binding assay.

RESULTS

Significantly increased levels of neuropeptides and inflammatory cytokines were observed in synovium and SF from patients in the severe DDH group compared with the moderate DDH and control groups. In moderate DDH samples, SP in SF correlated with tumor necrosis factor (TNF)-α, and CGRP in SF correlated with TNF-α and interleukin (IL)-10. In the severe DDH group, SP in SF correlated with interleukin (IL)-1β, TNF-α and IL-10. CGRP in SF correlated with TNF-α. Additionally, SP might have had obvious proinflammatory effects on synoviocytes through the activation of NF-κB.

CONCLUSIONS

The upregulation of SP and CGRP in synovium and SF might participate in the inflammatory process of arthritis in DDH. The activation of the NF-κB pathway seems indispensable in the proinflammatory effect of SP on synoviocytes. This original discovery may indicate a potential clinical drug target and the development of innovative therapies for DDH.

Effects of cichoric acid extract from Echinacea purpurea on collagen-induced arthritis in rats

Cichoric acid extract (CAE) from Echinacea purpurea L. was used to investigate the anti-arthritic effect by using collagen-induced arthritis (CIA) rat model. The hind paw swelling volume and the body weight were measured and recorded. All the drug solutions were administered orally to rats for a total of 28 days. On day 28, the rats were anaesthetized and decapitated. The thymus and spleen were weighed for the determination of the organ index. The concentration of tumor necrosis factor alpha (TNFα), interleukin-1 beta (IL-1β) and prostaglandin E2 (PGE-2) in the serum was measured using commercially available ELISA kits. Total and phosphor-NF-κB and Cox-2 protein expression in synovial tissues were determined by histological slides quantification and western blot analysis. Our data showed that administration of all doses of CAE (8, 16, and 32 mg/kg) significantly decreased the paw swelling, restored body weight gain and decreased the organ index of the thymus and spleen compared with that of the CIA group. CAE (8, 16, and 32 mg/kg) treatment significantly reduced the levels of TNFα, IL-1β and PGE-2 in serum compared with the CIA group. Histopathological analysis demonstrated that CAE has obvious anti-arthritic activity. In addition, CAE (32 mg/kg) significantly decreased the levels of nuclear factor-κB (NF-κB), TNFα and cyclooxygenase 2 (Cox-2) in synovium tissues of the ankle joint compared with the CIA group. Furthermore, CAE administration significantly decreased the protein expression of phosphor-NF-κB and Cox-2 in synovium tissues of the knee joint compared with the CIA group. The results suggest that the anti-inflammatory activity of CAE may account for its anti-arthritic effect, and CAE could be a potential therapeutic drug for the treatment of rheumatoid arthritis (RA).

Selenoproteins and selenium status in bone physiology and pathology

BACKGROUND

Emerging evidence supports the view that selenoproteins are essential for maintaining bone health.

SCOPE OF REVIEW

The current state of knowledge concerning selenoproteins and Se status in bone physiology and pathology is summarized.

MAJOR CONCLUSIONS

Antioxidant selenoproteins including glutathione peroxidase (GPx) and thioredoxin reductase (TrxR), as a whole, play a pivotal role in maintaining bone homeostasis and protecting against bone loss. GPx1, a major antioxidant enzyme in osteoclasts, is up-regulated by estrogen, an endogenous inhibitor of osteoclastogenesis. TrxR1 is an immediate early gene in response to 1α,25-dihydroxyvitamin D3, an osteoblastic differentiation agent. The combination of 1α,25-dihydroxyvitamin D3 and Se generates a synergistic elevation of TrxR activity in Se-deficient osteoblasts. Of particular concern, pleiotropic TrxR1 is implicated in promoting NFκB activation. Coincidentally, TrxR inhibitors such as curcumin and gold compounds exhibit potent osteoclastogenesis inhibitory activity. Studies in patients with the mutations of selenocysteine insertion sequence-binding protein 2, a key trans-acting factor for the co-translational insertion of selenocysteine into selenoproteins have clearly established a causal link of selenoproteins in bone development. Se transport to bone relies on selenoprotein P. Plasma selenoprotein P concentrations have been found to be positively correlated with bone mineral density in elderly women.

GENERAL SIGNIFICANCE

A full understanding of the role and function of selenoproteins and Se status on bone physiology and pathology may lead to effectively prevent against or modify bone diseases by using Se.

Chemopreventive effects of a curcumin-like diarylpentanoid [2,6-bis(2,5-dimethoxybenzylidene)cyclohexanone] in cellular targets of rheumatoid arthritis in vitro

AIM

Synovial fibroblast has emerged as a potential cellular target in progressive joint destruction in rheumatoid arthritis development. In this study, BDMC33 (2,6-bis[2,5-dimethoxybenzylidene]cyclohexanone), a curcumin analogue with enhanced anti-inflammatory activity has been synthesized and the potency of BDMC33 on molecular and cellular basis of synovial fibroblasts (SF) were evaluated in vitro.

METHODS

Synovial fibroblast cells (HIG-82) were cultured in vitro and induced by phorbol-12-myristate acetate (PMA) to stimulate the expression of matrix metalloproteinase (MMPs) and pro-inflammatory cytokines. The protective effects of BDMC33 were evaluated toward MMP activities, pro-inflammatory cytokine expression and nuclear factor kappa-B (NF-κB) activation by using various bioassay methods, including zymography, Western blotting, reverse transcription polymerase chain reaction, immunofluorescense microscopy and electrophoretic mobility shift assay.

RESULTS

The results showed that BDMC33 significantly inhibited the pro-gelatinase B (pro-MMP-9) and collagenase activities via suppression of MMP-1 in activated SF. In addition, BDMC33 strongly suppressed MMP-3 gene expression as well as inhibited COX-2 and IL-6 pro-inflammatory gene expression. We also demonstrated that BDMC33 abolished the p65 NF-κB nuclear translocation and NF-κB DNA binding activity in PMA-stimulated SF.

CONCLUSIONS

BDMC33 represents an effective chemopreventive agent and could be used as a promising lead compound for further development of rheumatoid arthritis therapeutic intervention.

β-Ecdysterone suppresses interleukin-1β-induced apoptosis and inflammation in rat chondrocytes via inhibition of NF-κB signaling pathway

Osteoarthritis (OA) is characterized by a loss of articular cartilage accompanied with inflammation of synovium. β-Ecdysterone (Ecd), a major component of several Chinese herbal medicines, e.g., Achyranthes bidentata BL., has been used for the prevention and treatment of OA. Ecd is an estrogen analog and is likely to have similar pharmacological effects including the effect of protective chondrocytes. This study investigated the effects of Ecd on interleukin-1β (IL-1β)-induced apoptosis and inflammation in rat chondrocytes. Ecd protected chondrocytes from IL-1β-induced injury by inhibiting expression of Bax, p53 phosphorylation, and promoting expression of Bcl-xL . Simultaneously, Ecd reduced caspase 3 activity. IL-1β-induced inflammation and matrix degration were also prevented by Ecd via down-regulation of matrix metalloproteinases MMP 3, MMP 9, and cyclooxygenase-2 expression. Additionally, Ecd inhibited Nuclear Factor Kappa B (NF-κB) p65 phosphorylation, IκBα degradation, and phosphorylation in IL-1β-induced rat chondrocytes. These results suggested Ecd exerted anti-apoptosis and anti-inflammation in IL-1β-induced rat chondrocytes, which might be related to NF-κB signal pathway.

Inhibition of glycogen synthase kinase-3β suppresses inflammatory responses in rheumatoid arthritis fibroblast-like synoviocytes and collagen-induced arthritis

OBJECTIVES

Glycogen synthase kinase (GSK)-3β, a serine/threonine protein kinase, has been implicated as a regulator of the inflammatory response. This study was performed to evaluate the effect of selective GSK-3β inhibitors in rheumatoid arthritis (RA) fibroblast-like synoviocytes (FLS) and collagen-induced arthritis (CIA).

METHOD

FLS from RA patients were treated with selective GSK-3β inhibitors, including lithium chloride, 6-bromoindirubin-3'-oxime (BIO), or 4-benzyl-2-methyl-1,2,4-thiadiazolidine-3,5-dione (TDZD-8). The effects of GSK-3β inhibition on pro-inflammatory mediators were determined by real-time PCR and ELISA. The levels of NF-κB, phosphorylated JNK, c-jun, ATF-2 and p-38 proteins were evaluated by western blot analysis. The in vivo effects of GSK-3β inhibitors were examined in mice with CIA.

RESULTS

Treatment of RA FLS with GSK-3β inhibitors induced dose-dependent reductions in gene expression and the production of pro-inflammatory mediators. The levels of NF-κB, phosphorylated JNK, c-jun, ATF-2 and p-38 were decreased following treatment with GSK-3β inhibitors. GSK-3β inhibitors treatment attenuated clinical and histological severities of CIA in mice. Infiltration of T-cells, macrophages, and tartrate-resistant acid phosphatase positive cells was decreased in joint sections of CIA mice by GSK-3β inhibitors treatment. Serum levels of IL-1β, IL-6, TNF-α and IFN-γ in CIA mice were also significantly decreased in dose-dependent manners by treatment with GSK-3β inhibitors.

CONCLUSION

Treatment with GSK-3β inhibitors suppressed inflammatory responses in RA FLS and CIA mice. These findings suggest that the inhibition of GSK-3β can be used as an effective therapeutic agent for RA.

Absence of Fms-like tyrosine kinase 3 ligand (Flt3L) signalling protects against collagen-induced arthritis

OBJECTIVE

Comprehending the mechanisms that regulate activation of autoreactive T cells and B cell antibody production is fundamental for understanding the breakdown in self-tolerance and development of autoimmunity. Here we studied the role of Fms-like tyrosine kinase 3 ligand (Flt3L) signalling in the pathogenesis of collagen-induced arthritis (CIA).

METHODS

CIA was induced in mice lacking Flt3L (Flt3L(-/-)) and wild-type (WT) littermates (C57/BL6, 8-10 weeks old). Mice were killed in the initial phase (acute phase: experiment 1) and late phase (chronic phase: experiment 2) of the disease. Arthritis severity was assessed using a semiquantitative scoring system (0-4), and histological analysis of cellular infiltration, cartilage destruction and peptidoglycan loss was performed. Phenotypic and functional analysis of T and B cells, FoxP3 expression, activation and lymphocyte costimulatory markers, and cytokine production were performed ex vivo by flow cytometry in lymph nodes. Serum collagen type II (CII)-specific antibodies were measured by ELISA.

RESULTS

Flt3L(-/-) mice showed a marked decrease in clinical arthritis scores and incidence of arthritis in both acute and chronic phases of CIA compared with WT mice. Moreover, decreased synovial inflammation and joint destruction was observed. Both the magnitude and quality of T cell responses were altered in Flt3L(-/-). In the acute phase, the amount of CII-specific IgG2a antibodies was lower in Flt3L(-/-) than WT mice.

CONCLUSIONS

These results strongly suggest a role for Flt3L signalling in the development of arthritis.

Botanical Extracts from Rosehip (Rosa canina), Willow Bark (Salix alba), and Nettle Leaf (Urtica dioica) Suppress IL-1β-Induced NF-κB Activation in Canine Articular Chondrocytes

The aim of this study was to characterize the anti-inflammatory mode of action of botanical extracts from rosehip (Rosa canina), willow bark (Salix alba), and nettle leaf (Urtica dioica) in an in vitro model of primary canine articular chondrocytes. Methods. The biological effects of the botanical extracts were studied in chondrocytes treated with IL-1β for up to 72 h. Expression of collagen type II, cartilage-specific proteoglycan (CSPG), β1-integrin, SOX-9, COX-2, and MMP-9 and MMP-13 was examined by western blotting. Results. The botanical extracts suppressed IL-1β-induced NF-κB activation by inhibition of IκBα phosphorylation, IκBα degradation, p65 phosphorylation, and p65 nuclear translocation. These events correlated with downregulation of NF-κB targets including COX-2 and MMPs. The extracts also reversed the IL-1β-induced downregulation of collagen type II, CSPG, β1-integrin, and cartilage-specific transcription factor SOX-9 protein expression. In high-density cultures botanical extracts stimulated new cartilage formation even in the presence of IL-1β. Conclusions. Botanical extracts exerted anti-inflammatory and anabolic effects on chondrocytes. The observed reduction of IL-1β-induced NF-κB activation suggests that further studies are warranted to demonstrate the effectiveness of plant extracts in the treatment of OA and other conditions in which NF-κB plays pathophysiological roles.

Treatment with recombinant Hsp72 suppresses collagen-induced arthritis in mice

Although the level of heat shock protein (Hsp72) has been shown to be enhanced in rheumatoid arthritis (RA) synovial tissues and RA synovial fluid, it remains unclear what role extracellular Hsp72 plays in the pathogenesis of RA. This study was conducted to investigate the effects of recombinant human Hsp72 on collagen-induced arthritis (CIA) when administered therapeutically and elucidate its underlying mechanism. We demonstrated that recombinant Hsp72 significantly reduced disease severity. Hsp72-treated animals displayed significantly less cartilage and bone destruction than that in the controls. Hsp72 treatment also reduced the expression of tumor necrosis factor alpha and interleukin 6 in the sera. Furthermore, Hsp72 treatment significantly inhibited activation of nuclear factor kappa B (NF-κB) in synovial tissues of CIA mice. These findings suggest that recombinant Hsp72 effectively suppressed synovial inflammation and the development and progress of CIA, which is mediated through the reduction of production of proinflammatory cytokines and the suppression of activation of NF-κB pathway.

4SC-101, a novel immunosuppressive drug, inhibits IL-17 and attenuates colitis in two murine models of inflammatory bowel disease

BACKGROUND

Dihydroorotate dehydrogenase (DHODH) is a key enzyme involved in pyrimidine biosynthesis. DHODH is a known target for the treatment of autoimmune diseases. 4SC-101 is a novel immunosuppressive drug that inhibits DHODH. A goal of our study was to examine the in vitro effects of 4SC-101 on IL-17 production by mononuclear cells. In addition, we evaluated the efficacy of 4SC-101 against acute TNBS (2,4,6-tritrobenzene sulfonic acid) and chronic dextran sodium sulfate (DSS)-induced colitis in mice.

METHODS

Peripheral blood mononuclear cells (PBMCs) from healthy human donors were used to evaluate cellular proliferation and cytokine (IL-17, TNF-α) production. The oral effects of 4SC-101 (100 or 200 mg/kg) were examined following induction of chronic colitis by the administration of 3% DSS (4 cycles) to Balb/c mice. Morphometric and histological indices of colitis were evaluated as indicators of drug efficacy. 4SC-101 was also administered for 6 days after the intracolonic administration of TNBS (20 mg in 50% ethanol) to female Balb/c mice. The colons were analyzed for overall macroscopic damage, ulceration, total length, distal segment weight, MPO activity, and histological pathology as indicators for the effectiveness of 4SC-101.

RESULTS

In vitro, 4SC-101 is a potent inhibitor of human DHODH, inhibits lymphocyte proliferation, and uniquely blocks phytohemagglutinin-stimulated IL-17 production by lymphocytes. In vivo, oral administration of 4SC-101 effectively improved both chronic DSS and acute TNBS colitis in mice. In these colitis models the overall efficacy profile of 4SC-101 was similar to that of dexamethasone.

CONCLUSIONS

4SC-101 is a novel immunosuppressive drug with excellent potential for the treatment of intestinal inflammation.

Shear-induced interleukin-6 synthesis in chondrocytes: roles of E prostanoid (EP) 2 and EP3 in cAMP/protein kinase A- and PI3-K/Akt-dependent NF-kappaB activation

Mechanical overloading of cartilage producing hydrostatic stress, tensile strain, and fluid flow can adversely affect chondrocyte function and precipitate osteoarthritis (OA). Application of high fluid shear stress to chondrocytes recapitulates the earmarks of OA, as evidenced by the release of pro-inflammatory mediators, matrix degradation, and chondrocyte apoptosis. Elevated levels of cyclooxygenase-2 (COX-2), prostaglandin (PG) E(2), and interleukin (IL)-6 have been reported in OA cartilage in vivo, and in shear-activated chondrocytes in vitro. Although PGE(2) positively regulates IL-6 synthesis in chondrocytes, the underlying signaling pathway of shear-induced IL-6 expression remains unknown. Using the human T/C-28a2 chondrocyte cell line as a model system, we demonstrate that COX-2-derived PGE(2) signals via up-regulation of E prostanoid (EP) 2 and down-regulation of EP3 receptors to raise intracellular cAMP, and activate protein kinase A (PKA) and phosphatidylinositol 3-kinase (PI3-K)/Akt pathways. PKA and PI3-K/Akt transactivate the NF-kappaB p65 subunit via phosphorylation at Ser-276 and Ser-536, respectively. Binding of p65 to the IL-6 promoter elicits IL-6 synthesis in sheared chondrocytes. Selective knockdown of EP2 or ectopic expression of EP3 blocks PKA- and PI3-K/Akt-dependent p65 activation and markedly diminishes shear-induced IL-6 expression. Similar inhibitory effects on IL-6 synthesis were observed by inhibiting PKA, PI3-K, or NF-kappaB using pharmacological and/or genetic interventions. Reconstructing the signaling network regulating shear-induced IL-6 expression in chondrocytes may provide insights for developing therapeutic strategies for arthritic disorders and for culturing artificial cartilage in bioreactors.

Curcumin mediated suppression of nuclear factor-κB promotes chondrogenic differentiation of mesenchymal stem cells in a high-density co-culture microenvironment

Introduction

Osteoarthritis (OA) and rheumatoid arthritis (RA) are characterised by joint inflammation and cartilage degradation. Although mesenchymal stem cell (MSC)-like progenitors are resident in the superficial zone of articular cartilage, damaged tissue does not possess the capacity for regeneration. The high levels of pro-inflammatory cytokines present in OA/RA joints may impede the chondrogenic differentiation of these progenitors. Interleukin (IL)-1β activates the transcription factor nuclear factor-κB (NF-κB), which in turn activates proteins involved in matrix degradation, inflammation and apoptosis. Curcumin is a phytochemical capable of inhibiting IL-1β-induced activation of NF-κB and expression of apoptotic and pro-inflammatory genes in chondrocytes. Therefore, the aim of the present study was to evaluate the influence of curcumin on IL-1β-induced NF-κB signalling pathway in MSCs during chondrogenic differentiation.

Methods

MSCs were either cultured in a ratio of 1:1 with primary chondrocytes in high-density culture or cultured alone in monolayer with/without curcumin and/or IL-1β.

Results

We demonstrate that although curcumin alone does not have chondrogenic effects on MSCs, it inhibits IL-1β-induced activation of NF-κB, activation of caspase-3 and cyclooxygenase-2 in MSCs time and concentration dependently, as it does in chondrocytes. In IL-1β stimulated co-cultures, four-hour pre-treatment with curcumin significantly enhanced the production of collagen type II, cartilage specific proteoglycans (CSPGs), β1-integrin, as well as activating MAPKinase signaling and suppressing caspase-3 and cyclooxygenase-2.

Conclusions

Curcumin treatment may help establish a microenvironment in which the effects of pro-inflammatory cytokines are antagonized, thus facilitating chondrogenesis of MSC-like progenitor cells in vivo. This strategy may support the regeneration of articular cartilage.

Synergistic chondroprotective effects of curcumin and resveratrol in human articular chondrocytes: inhibition of IL-1beta-induced NF-kappaB-mediated inflammation and apoptosis

Introduction

Currently available treatments for osteoarthritis (OA) are restricted to nonsteroidal anti-inflammatory drugs, which exhibit numerous side effects and are only temporarily effective. Thus novel, safe and more efficacious anti-inflammatory agents are needed for OA. Naturally occurring polyphenolic compounds, such as curcumin and resveratrol, are potent agents for modulating inflammation. Both compounds mediate their effects by targeting the NF-κB signalling pathway.

Methods

We have recently demonstrated that in chondrocytes resveratrol modulates the NF-κB pathway by inhibiting the proteasome, while curcumin modulates the activation of NF-κB by inhibiting upstream kinases (Akt). However, the combinational effects of these compounds in chondrocytes has not been studied and/or compared with their individual effects. The aim of this study was to investigate the potential synergistic effects of curcumin and resveratrol on IL-1β-stimulated human chondrocytes in vitro using immunoblotting and electron microscopy.

Results

Treatment with curcumin and resveratrol suppressed NF-κB-regulated gene products involved in inflammation (cyclooxygenase-2, matrix metalloproteinase (MMP)-3, MMP-9, vascular endothelial growth factor), inhibited apoptosis (Bcl-2, Bcl-xL, and TNF-α receptor-associated factor 1) and prevented activation of caspase-3. IL-1β-induced NF-κB activation was suppressed directly by cocktails of curcumin and resveratrol through inhibition of Iκκ and proteasome activation, inhibition of IκBα phosphorylation and degradation, and inhibition of nuclear translocation of NF-κB. The modulatory effects of curcumin and resveratrol on IL-1β-induced expression of cartilage specific matrix and proinflammatory enzymes were mediated in part by the cartilage-specific transcription factor Sox-9.

Conclusions

We propose that combining these natural compounds may be a useful strategy in OA therapy as compared with separate treatment with each individual compound.

Gene therapy targeting nuclear factor-kappaB: towards clinical application in inflammatory diseases and cancer

Nuclear factor (NF)-κB is regarded as one of the most important transcription factors and plays an essential role in the transcriptional activation of pro-inflammatory cytokines, cell proliferation and survival. NF-κB can be activated via two distinct NF-κB signal transduction pathways, the so-called canonical and non-canonical pathways, and has been demonstrated to play a key role in a wide range of inflammatory diseases and various types of cancer. Much effort has been put in strategies to inhibit NF-κB activation, for example by the development of pharmacological compounds that selectively inhibit NF-κB activity and therefore would be beneficial for immunotherapy of transplantation, autoimmune and allergic diseases, as well as an adjuvant approach in patients treated with chemotherapy for cancer. Gene therapy targeting NF-κB is a promising new strategy with the potential of long-term effects and has been explored in a wide variety of diseases, ranging from cancer to transplantation medicine and autoimmune diseases. In this review we discuss recent progress made in the development of NF-κB targeted gene therapy and the evolution towards clinical application.

Amelioration of alphavirus-induced arthritis and myositis in a mouse model by treatment with bindarit, an inhibitor of monocyte chemotactic proteins

OBJECTIVE

Alphaviruses such as chikungunya virus, Sindbis virus, o'nyong-nyong virus, Mayaro virus, and Ross River virus (RRV), are commonly associated with arthralgias and overt arthritides worldwide. Understanding the processes by which arthritogenic viruses cause disease is a prerequisite in the quest for better treatments. In this regard, we have recently established that monocyte/macrophages are mediators of alphavirus-induced arthritis in mice. We hypothesized that chemokines associated with monocyte/macrophage recruitment may play an important role in disease. The aim of the present investigations was to determine whether bindarit, an inhibitor of monocyte chemotactic protein (MCP) synthesis, could ameliorate alphavirus-induced rheumatic disease in mice.

METHODS

Using our recently developed mouse model of RRV-induced arthritis, which has many characteristics of RRV disease (RRVD) in humans, the effects of bindarit treatment on RRVD in mice were determined via histologic analyses, immunohistochemistry, flow cytometry, real-time polymerase chain reaction analysis, enzyme-linked immunosorbent assay, and electrophoretic mobility shift assay.

RESULTS

Bindarit-treated RRV-infected mice developed mild disease and had substantially reduced tissue destruction and inflammatory cell recruitment as compared with untreated RRV-infected mice. The virus load in the tissues was not affected by bindarit treatment. Bindarit exhibited its activity by down-regulating MCPs, which in turn led to inhibition of cell infiltration and lower production of NF-kappaB and tumor necrosis factor alpha, which are involved in mediating tissue damage.

CONCLUSION

Our data support the use of inhibitors of MCP production in the treatment of arthritogenic alphavirus syndromes and suggest that bindarit may be useful in treating RRVD and other alphavirus-induced arthritides in humans.

Functional roles for T cell CD40 in infection and autoimmune disease: the role of CD40 in lymphocyte homeostasis

CD40 stimulation on monocytes/macrophages, dendritic cells, and B-lymphocytes has been the subject of much study. It is well recognized that activation of CD40 on antigen presenting cells by its ligand, CD154, expressed on T-lymphocytes, contributes to the pro-inflammatory response necessary for eradication of infection, yet pathological in autoimmunity. However, there is evidence that CD40 is also expressed on T-lymphocytes and can act as a costimulatory molecule. While the exact role of CD40 on CD8 T cells remains controversial, it does appear to contribute to the adaptive immune response against infection. CD40 on CD4 T cells, on the other hand, plays a functional role in the autoimmune disease process. Further dissection of the exact nature and role of CD40 in T cell activation could lead the way to more effective vaccines and novel therapeutics for autoimmune diseases.

Macrophage-derived proinflammatory factors contribute to the development of arthritis and myositis after infection with an arthrogenic alphavirus

Alphaviruses, such as chikungunya virus and Ross River virus (RRV), are associated with outbreaks of infectious rheumatic disease in humans worldwide. Using an established mouse model of disease that mimics RRV disease in humans, we showed that macrophage-derived factors are critical in the development of striated muscle and joint tissue damage. Histologic analyses of muscle and ankle joint tissues demonstrated a substantial reduction in inflammatory infiltrates in infected mice depleted of macrophages (i.e., "macrophage-depleted mice"). Levels of the proinflammatory factors tumor necrosis factor-alpha, interferon-gamma, and macrophage chemoattractant protein-1 were also dramatically reduced in tissue samples obtained from infected macrophage-depleted mice, compared with samples obtained from infected mice without macrophage depletion. These factors were also detected in the synovial fluid of patients with RRV-induced polyarthritis. Neutralization of these factors reduced the severity of disease in mice, whereas blocking nuclear factor kappaB by treatment with sulfasalazine ameliorated RRV inflammatory disease and tissue damage. To our knowledge, these findings are the first to demonstrate that macrophage-derived products play important roles in the development of arthritis and myositis triggered by alphavirus infection.

Treatment with N-tosyl-l-phenylalanine chloromethyl ketone after the onset of collagen-induced arthritis reduces joint erosion and NF-kappaB activation

N-tosyl-l-phenylalanine chloromethyl ketone (TPCK) is known to inhibit NF-kappaB activation and the expression of inflammation mediators in cultured cells. We measured the potential of TPCK to inhibit the pathogenesis of collagen-induced arthritis by blocking NF-kappaB activation. Arthritis was induced in DBA/1J mice by the injection of bovine type II collagen in adjuvant on days 0 and 14. Mice received either TPCK (3 or 10 mg/kg, i.p.) or vehicle three times a week for 3 weeks starting on day 21. TPCK moderately reduced clinical disease activity scores, whereas it markedly suppressed histological indications of joint destruction. In vitro production of tumor necrosis factor-alpha, interleukin-6, and monocyte chemotactic protein-1 from lipopolysaccharide-stimulated spleen cells was also reduced by in vivo treatment with TPCK. Proliferation of cells isolated from spleen or draining lymph nodes and production of interferon-gamma and interleukin-17 in response to stimulation with type II collagen was decreased by TPCK. Moreover, nuclear NF-kappaB activity induced by collagen immunization was significantly reduced in mice treated with TPCK. Finally, osteoclast differentiation of bone marrow cells induced by macrophage colony-stimulating factor and receptor activator of NF-kappaB ligand was completely inhibited by TPCK. These results indicate that TPCK attenuates collagen-induced arthritis and bone erosion by suppressing NF-kappaB activation and thus expression of inflammatory and osteoclastogenic genes.

Consumption of hydrolyzable tannins-rich pomegranate extract suppresses inflammation and joint damage in rheumatoid arthritis

OBJECTIVE

Although consumption of dietary supplements containing pomegranate extract (POMx) by patients with arthritis is on the rise, the efficacy of such preparations in suppressing joint inflammation and damage is not known. The present study was designed to evaluate a standardized preparation of POMx using collagen-induced arthritis (CIA) in mice, a widely used animal model of rheumatoid arthritis.

METHODS

CIA-susceptible DBA/1 mice were fed POMx by gavage before and after immunization with chicken type II collagen. Severity of clinical arthritis was scored using a visual scoring system. Arthritic joints were analyzed by histopathology and graded. Lysates were generated from mouse joints and levels of anti-type II collagen immunoglobulin G and inflammatory cytokines interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha were quantified by enzyme-linked immunosorbent assay. The effect of POMx on lipopolysaccharide-induced nitric oxide production was determined by Griess reaction and mitogen-activated protein kinase activation was studied by western immunoblotting in mouse macrophages.

RESULTS

Consumption of POMx potently delayed the onset and reduced the incidence of CIA in mice. Severity of arthritis was also significantly lower in POMx-fed animals. Histopathology of the arthritic joints from POMx-fed mice demonstrated reduced joint infiltration by the inflammatory cells, and the destruction of bone and cartilage were alleviated. Levels of IL-6 were significantly decreased in the joints of POMx-fed mice with CIA. In mouse macrophages, POMx abrogated multiple signal transduction pathways and downstream mediators implicated in the pathogenesis of rheumatoid arthritis.

CONCLUSION

Our studies suggest that inhibition of a spectrum of signal transduction pathways and the downstream pathogenic cellular response by POMx or compounds derived from it may be a useful approach for the prevention of the onset and severity of inflammatory arthritis.

IL-17B and IL-17C are associated with TNF-alpha production and contribute to the exacerbation of inflammatory arthritis

IL-17A is a T cell-derived proinflammatory cytokine that contributes to the pathogenesis of rheumatoid arthritis. Recently, six related molecules have been identified to form the IL-17 family, as follows: IL-17A, IL-17B, IL-17C, IL-17D, IL-17E, and IL-17F. Whereas IL-17A and IL-17F up-regulate IL-6 in synovial fibroblasts, IL-17B and IL-17C are reported to stimulate the release of TNF-alpha and IL-1beta from the monocytic cell line, THP-1 cell. However, their detailed function remains to be elucidated. We report in this study the effects of IL-17 family on the collagen-induced arthritis (CIA) progression by T cell gene transfer and bone marrow chimeric mice. The mRNA expressions of IL-17 family (IL-17A, IL-17B, IL-17C, and IL-17F) and their receptor (IL-17R and IL-17Rh1) genes in the arthritic paws of CIA mice were elevated compared with controls. Although IL-17A and IL-17F were expressed in CD4(+) T cells, IL-17B and IL-17C were expressed in the cartilage and in various cell populations in the CIA arthritic paws, respectively. In vitro, IL-17A, IL-17B, IL-17C, and IL-17F induced TNF-alpha production in mouse peritoneal exudate cells. In vivo, adoptive transfer of IL-17B- and IL-17C-transduced CD4(+) T cells evidently exacerbated arthritis. Bone marrow chimeric mice of IL-17B and IL-17C exhibited elevated serum TNF-alpha concentration and the high arthritis score upon CIA induction. Moreover, neutralization of IL-17B significantly suppressed the progression of arthritis and bone destruction in CIA mice. Therefore, not only IL-17A, but also IL-17B and IL-17C play an important role in the pathogenesis of inflammatory arthritis.

Inhibition of Nuclear Factor-κB in T Cells Suppresses Lung Fibrosis

RATIONALE

Cytokines secreted by T cells play a pivotal role in the pathogenesis of lung injury and fibrosis, and the transcription factors nuclear factor (NF)-kappaB and activator protein (AP)-1 are involved in the expression of cytokines from T cells during lung injury.

OBJECTIVES

We assessed the potential therapeutic effect of SP100030, a specific inhibitor of T-cell NF-kappaB and AP-1 in lung fibrosis.

METHODS

The effect of SP100030 was evaluated using a mouse model of chronic lung fibrosis.

MEASUREMENTS AND MAIN RESULTS

Mice treated with SP100030, as compared with untreated mice, had significantly less cachexia and less lung injury and had decreased levels of inflammatory cytokines and growth factors, decreased activation of coagulation activation, and decreased collagen deposition in the lung. The inhibitory activity of SP100030 was dose dependent and was effective in acute and chronic phases of lung fibrosis. SP100030 inhibited the activation of the protein kinase C-isoform in T-cell lines and suppressed NF-kappaB-driven cytokine expression in CD4(+) and CD8(+) T cells.

CONCLUSIONS

These results suggest that the specific inhibition of NF-kappaB could be useful for the treatment of lung fibrosis.

Effects of resveratrol in inflammatory arthritis

Nuclear factor kappa B (NF-kappaB), is a pivotal transcription factor involved in the activation of the TNF-alpha and IL-1beta genes. Activation of NF-kappaB in synovial cells is a feature seen in arthritis patients. Resveratrol, a polyphenolic, natural phytoalexin found with particularly high levels in grape skin and red wine is potent and specific inhibitor of TNF-alpha and IL-1beta induced NF-kappaB activation. We aimed to determine the in vivo effects of intra-articular injections of resveratrol on cartilage and synovium in an experimental rabbit inflammatory arthritis model.

MATERIALS AND METHODS

Arthritis was induced by intra-articular injection of three times of 50 mug lipopolysaccharide (LPS) at day 0, 4 and 8 at 4-day intervals into the knee joints of rabbits. To the test group, 10 muMol/kg resveratrol in the DMSO was injected in the knees at day 0 and then it was continued once daily for 2 weeks. To the control group the same time and amount of DMSO was injected the knees of rabbits. All rabbits were killed 1 week after the last injection and cartilage tissue and synovium were evaluated with semiquantitative scoring histologically.

RESULTS

According to control group in the resveratrol group, significantly decreased cartilage destruction was determined by H&E staining (p = 0.04). Loss of matrix proteoglycan content in the cartilage was much lower, as determined by safranin O staining (p = 0.03). We also observed marked synovial inflammation after intra-articular injection to control knees, but not in the resveratrol treated group knees (p = 0.01).

CONCLUSION

This study suggests that intra-articular injection of resveratrol may protect cartilage against the development of experimentally induced IA.

CTLA-4IG suppresses reactive oxygen species by preventing synovial adherent cell-induced inactivation of rap1, a ras family GTPASE mediator of oxidative stress in rheumatoid arthritis T cells

OBJECTIVE

Oxidative stress contributes to the inflammatory properties of rheumatoid arthritis (RA) synovial T lymphocytes. This study was undertaken to investigate the mechanisms leading to production of reactive oxygen species (ROS) and oxidative stress in RA synovial T lymphocytes.

METHODS

ROS production in T lymphocytes from the peripheral blood (PB) of healthy donors and from the PB and synovial fluid (SF) of RA patients was measured by ROS-dependent fluorescence of 6-carboxy-2',7'-dichlorofluorescein. Rap1 GTPase activation was assessed by activation-specific probe precipitation. Proliferation of RA PB and SF T lymphocytes was assayed by 3H-thymidine incorporation. In some experiments, RA PB T cells were preincubated with autologous SF or with PB or SF adherent cells. Experiments were performed in the absence or presence of transwell membranes or CTLA-4Ig fusion proteins. Short- and long-term stimulations of healthy donor PB T lymphocytes were performed with inflammatory cytokines, in the absence or presence of activating anti-CD28 antibodies.

RESULTS

T lymphocyte ROS production and Rap1 inactivation were mediated by cell-cell contact with RA synovial adherent cells, and this correlated with T cell mitogenic hyporesponsiveness. CTLA4-Ig blockade of synovial adherent cell signaling to CD28 T cells reversed the inhibition of Rap1 activity and prevented induction of ROS. Introduction of active RapV12 into T cells also prevented induction of ROS production. Coincubation of T cells with stimulating anti-CD28 antibodies and inflammatory cytokines synergistically increased T cell ROS production.

CONCLUSION

Cell-cell contact between T cells and RA synovial adherent cells mediates Rap1 inactivation and subsequent ROS production in T lymphocytes following exposure to inflammatory cytokines. This process can be blocked by CTLA4-Ig fusion protein.

NOD2 allele variants in patients with rheumatoid arthritis

Recent reports have proven the importance of genetic factors and inflammation in the pathogenesis of rheumatoid arthritis (RA). In the current study, the frequency of NOD2/CARD15 gene variants (R702W, G908R, and L1007fsinsC) was examined in a group of 243 RA patients and 220 healthy controls. There were no statistically significant differences in distribution of NOD2 variant alleles between RA patients and controls. Moreover, there was no significant association between NOD2 variant alleles and joint erosions, extraarticular manifestations, rheumatoid factor, number of swollen and tender joints, and erythrocyte sedimentation rate. The results of the present study suggest that NOD2 allele variants have no significant influence on RA susceptibility, activity, and severity.

Alpha-lipoic acid suppresses the development of collagen-induced arthritis and protects against bone destruction in mice

OBJECTIVE

To test the ability of alpha-lipoic acid (LA) to attenuate the development of collagen-induced arthritis (CIA) in mice.

METHODS

Mice were divided into three groups and treated with intraperitoneal administration of LA (10 or 100 mg/kg) or placebo. Clinical, histologic, and biochemical parameters were assessed. Human synovial fibroblasts and peripheral blood mononuclear cells were cocultured in various concentrations of LA to evaluate the effects on osteoclastogenesis.

RESULTS

LA was associated with a dose-dependent reduction of CIA, as well as preventing bone erosion and destructive changes. Intracellular reactive oxygen species in lymphocytes obtained from inguinal lymph nodes, which was significantly higher in CIA than control mice, was significantly reduced in CIA by LA. The concentrations of TNF-alpha, IL-1beta, and IL-6 in the paws, and synovial NF-kappaB binding, all of which were markedly higher in CIA than control mice, were reduced by treatment with LA. In addition, LA inhibited the formation of human osteoclasts in vitro.

CONCLUSION

Amelioration of joint disease by LA was associated with reduction in oxidative stress, as well as inhibition of inflammatory cytokine activation and NF-kappaB DNA binding activity. Moreover, LA inhibited bone destruction in vivo and osteoclastogenesis in vitro. Collectively, these results indicate that LA may be a new adjunctive therapy for rheumatoid arthritis.

Effects of cyclooxygenase-2 inhibition on serum and tumor gastrins and expression of apoptosis-related proteins in colorectal cancer

The objective of the present study was to determine the influence of cyclooxygenase-2 (COX-2) inhibition by Celecoxib (CLX) in humans with distal colorectal adenocarcinoma (CRC) on serum and tumor levels of progastrin and gastrin and serum levels of proinflammatory cytokines (IL-8, TNF-alpha). In addition, the effects of this CLX treatment on tumor and adjacent mucosa expression of gastrin, its receptors (CCK2), and COX-1 and COX-2, as well as protein expression of the active form of nuclear factor kappa B (NFkappa B) and the apoptotic-related proteins Bcl-2 and survivin, have been examined. Ten distal CRC patients were examined twice, once before and then after 14-day treatment with CLX (200 mg bid). Large biopsy samples were taken from the tumor and intact mucosa 10 cm above the tumor. For comparison, 20 age- and sex-matched healthy controls were enrolled and treated with CLX as CRC patients. Serum levels of IL-8 and TNF-alpha were measured by enzyme-linked immunosorbent assay, and serum levels of amidated gastrins and progastrin, by specific radioimmunoassay. The gene or protein expressions of progastrin, gastrin, CCK2, COX-1, COX-2, Bcl-2, and survivin as well as NFkappa B were determined by RT-PCR or Western blot in biopsy samples of tumor and intact mucosa of CRC patients. Serum IL-8 and TNF-alpha values were severalfold higher in CRC patients than in controls. The increase in serum proinflammatory cytokines was accompanied by increased expression of the active form of NFkappa B. Serum progastrin levels were also found to be significantly higher in CRC than in controls. Treatment of CRC with CLX resulted in a significant decrease in serum levels of progastrin and this was accompanied by an increment in tumor expression of COX-2 with a concomitant reduction in gastrin, Bcl-2, survivin, and NFkappa B expression. We conclude that (1) distal CRC patients show significantly higher serum progastrin levels than matched healthy controls, confirming that this hormone may be implicated in rectal carcinogenesis; (2) CRC patients exhibit significantly higher serum levels of IL-8 and TNF-alpha than healthy controls, probably reflecting more widespread inflammatory reaction in the colonic mucosa in CRC; (3) gastrin, COX-2, Bcl-2, survivin, and NFkappa B were overexpressed in CRC tumor compared to intact mucosa, but treatment with CLX significantly reduced serum levels of progastrin and IL-8 and TNF-alpha, which could mediate the up-regulation of COX-2 in CRC; and (4) CLX also enhanced expression of COX-2, while inhibiting the expression of gastrin, Bcl-2, survivin, and NFkappa B, suggesting that COX-2 inhibition might be useful in chemoprevention against CRC, possibly due to suppression of the antiapoptotic proteins and reduction in progastrin-induced and NFkappa B-promoted tumor growth.