Macrophage inflammatory protein-1 alpha. A novel chemotactic cytokine for macrophages in rheumatoid arthritis

Leukocyte production of inflammatory mediators is inhibited by the antioxidants phloretin, silymarin, hesperetin, and resveratrol

Antioxidants possess significant therapeutic potential for the treatment of inflammatory disorders. One such disorder is periodontitis characterised by an antimicrobial immune response, inflammation, and irreversible changes to the supporting structures of the teeth. Recognition of conserved pathogen-associated molecular patterns is a crucial component of innate immunity to Gram-negative bacteria such as Escherichia coli, as well as the periodontal pathogen Aggregatibacter actinomycetemcomitans. In this study, we investigated the antioxidants Phloretin, Silymarin, Hesperetin, and Resveratrol to ascertain whether they altered the production of inflammatory mediators by innately-activated leukocytes. Peripheral blood mononuclear cells were stimulated with lipopolysaccharide purified from Aggregatibacter actinomycetemcomitans, and the production of cytokines, chemokines, and differentiation factors was assayed by enzyme-linked immunosorbent assay, cytometric bead array, and RT-PCR. Significant inhibition of these factors was achieved upon treatment with Phloretin, Silymarin, Hesperetin, and Resveratrol. These data further characterise the potent anti-inflammatory properties of antioxidants. Their ability to inhibit the production of inflammatory cytokines, chemokines, and differentiation factors by a heterogeneous population of leukocytes has clear implications for their therapeutic potential in vivo.

Fucosyltransferase 1 mediates angiogenesis, cell adhesion and rheumatoid arthritis synovial tissue fibroblast proliferation

INTRODUCTION

We previously reported that sialyl Lewis(y), synthesized by fucosyltransferases, is involved in angiogenesis. Fucosyltransferase 1 (fut1) is an α(1,2)-fucosyltransferase responsible for synthesis of the H blood group and Lewis(y) antigens. However, the angiogenic involvement of fut 1 in the pathogenesis of rheumatoid arthritis synovial tissue (RA ST) has not been clearly defined.

METHODS

Assay of α(1,2)-linked fucosylated proteins in RA was performed by enzyme-linked lectin assay. Fut1 expression was determined in RA ST samples by immunohistological staining. We performed angiogenic Matrigel assays using a co-culture system of human dermal microvascular endothelial cells (HMVECs) and fut1 small interfering RNA (siRNA) transfected RA synovial fibroblasts. To determine if fut1 played a role in leukocyte retention and cell proliferation in the RA synovium, myeloid THP-1 cell adhesion assays and fut1 siRNA transfected RA synovial fibroblast proliferation assays were performed.

RESULTS

Total α(1,2)-linked fucosylated proteins in RA ST were significantly higher compared to normal (NL) ST. Fut1 expression on RA ST lining cells positively correlated with ST inflammation. HMVECs from a co-culture system with fut1 siRNA transfected RA synovial fibroblasts exhibited decreased endothelial cell tube formation compared to control siRNA transfected RA synovial fibroblasts. Fut1 siRNA also inhibited myeloid THP-1 adhesion to RA synovial fibroblasts and RA synovial fibroblast proliferation.

CONCLUSIONS

These data show that α(1,2)-linked fucosylated proteins are upregulated in RA ST compared to NL ST. We also show that fut1 in RA synovial fibroblasts is important in angiogenesis, leukocyte-synovial fibroblast adhesion, and synovial fibroblast proliferation, all key processes in the pathogenesis of RA.

The roles of catabolic factors in the development of osteoarthritis

Osteoarthritis (OA) is the most prevalent disease of articular joints characterized by joint space narrowing on X-ray, joint pain, and a loss of joint function through progressive cartilage degradation and intermittent synovial inflammation. Current in vitro models of OA are often monolayer cultured primary cells exposed to high concentrations of cytokines or chemokines, usually IL-1β or TNF-α. IL-1β could play a role in the early progression or even initiation of OA as evidenced by many of the in vitro studies. However, the inconsistent or outright lack of detectable IL-1β combined with high concentrations of the natural inhibitor IL-1Ra in the OA synovial fluid makes the idea of OA being IL-1β-driven questionable. Further, other stimulants, including IL-6 and matrix fragments, have been shown in vitro to cause many of the effects seen in OA at relevant concentrations found in the OA synovial fluid. More work with these stimulants and IL-1β-independent models needs to be done. Concurrently, research should be conducted with patients with OA as early as possible in the progression of their disease to be able to potentially identify, target, and treat the initiation of the disease.

The degradation of chondrogenic pellets using cocultures of synovial fibroblasts and U937 cells

Osteoarthritis (OA) of the knee is often characterized by joint space narrowing on X-ray, knee pain, and a loss of joint function through progressive cartilage degradation and intermittent synovial inflammation. The objective of this work was to develop an in vitro model in a clinically relevant system. Normal human synovial fibroblasts were cultured with U937 cells for 3 days then combined with a chondrogenic stem cell pellet for another 4 days. This culture system mimicked many of the aspects of early stage OA including production of cytokines and degradative enzymes, MMP-1 and MMP-3, resulting in a conditioned medium profile similar to OA synovial fluid. This catabolic environment resulted in the release of glycosaminoglycan (GAG) from the pellet. In a similar manner to early stage OA, the pellet had increased aggrecan and collagen II expression. All of these effects are hallmarks of early stage OA. This relatively simple tissue model containing a 3D cartilage component interacting with synoviocytes and macrophages could be useful to understand early causes and progression of OA. It can be scaled easily thus useful for high throughput screening of disease modifying drugs in a clinically relevant system.

Circulating Porphyromonas gingivalis lipopolysaccharide resets cardiac homeostasis in mice through a matrix metalloproteinase-9-dependent mechanism

Porphyromonas gingivalis lipopolysaccharide (Pg-LPS) circulates systemically in over 50% of periodontal disease (PD) patients and is associated with increased matrix metalloproteinase (MMP)-9. We hypothesized that low systemic Pg-LPS would stimulate an inflammatory response in the left ventricle (LV) through MMP-9, leading to a decrease in cardiac function. Wild-type (WT) and MMP-9 null mice (4-7 months old) were exposed for 1 or 28 days to low dose Pg-LPS or saline (n ≥ 6/group). MMP-9 significantly increased in WT mice LV at 1 and 28 days of exposure, compared to control (P < 0.05 for both). Fractional shortening decreased subtly yet significantly in WT mice by day 28 (31 ± 1%) compared to control (35 ± 1%; P < 0.05), and this decrease was attenuated in null (34 ± 1%) mice. Plasma cardiac troponin I levels were elevated in WT mice at day 28. Macrophage-related factors increased over twofold in WT plasma and LV after day 1 (monocyte chemoattractant protein-5, macrophage inflammatory protein (MIP)-1α, MIP-1γ, stem cell factor, Ccl12, Ccl9, Il8rb, Icam1, Itgb2, and Spp1; all P < 0.05), indicating a moderate inflammatory response. Levels returned to baseline by day 28, suggesting tolerance to Pg-LPS. In contrast, macrophage-related factors remained elevated in day 28 null mice, indicating a sustained defense against Pg-LPS stimulation. Consistent with these findings, LV macrophage numbers increased in both groups at day 1 and returned to baseline by day 28 in the WT mice only. Major histocompatibility complex (MCH) II remained elevated in the null group at day 28, confirming Pg-tolerance in the WT. Interestingly Il-1α, a regulator of macrophage immunosuppression, increased in the plasma of WT mice only on day 28, suggesting that Il-1α plays a role in tolerance in a MMP-9-dependent manner. In conclusion, circulating Pg-LPS induced tolerance in WT mice, resulting in significant LV changes and subtle cardiac dysfunction. MMP-9 played a major role in the regulation of chronic systemic inflammation and associated cardiac dysfunction.

Triglyceride-induced macrophage cell death is triggered by caspase-1

Triglyceride (TG) induces macrophage cell death which contributes to the development of atherosclerosis. We confirmed that exogenous TG accumulates in human THP-1 macrophages and causes cell death. TG treated THP-1 macrophages exhibited no change in tumor necrosis factor (TNF)-α, interleukin (IL)-18, macrophage inflammatory protein (MIP)-1α, and IL-1R1 receptor mRNA expression. However, there was a marked decrease in IL-1β mRNA expression but an increase in IL-1β protein secretion. Decreased expression of IL-1β mRNA and increased secretion of IL-1β protein was not the direct cause of cell death. Until now, TG was assumed to induce necrotic cell death in macrophages. Since caspase-1 is known to be involved in activation and secretion of IL-1β protein and pyroptotic cell death, next we determined whether caspase-1 is associated with TG-induced macrophage cell death. We found an increase in caspase-1 activity in TG-treated THP-1 macrophages and inhibition of caspase-1 activity using a specific inhibitor partially rescued cell death. These results suggest activation of the pyroptotic pathway by TG. This is the first report implicating the activation of caspase-1 and the triggering of the pyroptosis pathway in TG-induced macrophage cell death.

The immunologic effects of maraviroc intensification in treated HIV-infected individuals with incomplete CD4+ T-cell recovery: a randomized trial

The CCR5 inhibitor maraviroc has been hypothesized to decrease T-cell activation in HIV-infected individuals, but its independent immunologic effects have not been established in a placebo-controlled trial. We randomized 45 HIV-infected subjects with CD4 counts <350 cells per mm(3) and plasma HIV RNA levels <48 copies per mL on antiretroviral therapy (ART) to add maraviroc vs placebo to their regimen for 24 weeks followed by 12 weeks on ART alone. Compared with placebo-treated subjects, maraviroc-treated subjects unexpectedly experienced a greater median increase in % CD38+HLA-DR+ peripheral blood CD8+ T cells at week 24 (+2.2% vs -0.7%, P = .014), and less of a decline in activated CD4+ T cells (P < .001). The % CD38+HLA-DR+ CD4+ and CD8+ T cells increased nearly twofold in rectal tissue (both P < .001), and plasma CC chemokine receptor type 5 (CCR5) ligand (macrophage-inflammatory protein 1β) levels increased 2.4-fold during maraviroc intensification (P < .001). During maraviroc intensification, plasma lipopolysaccharide declined, whereas sCD14 levels and neutrophils tended to increase in blood and rectal tissue. Although the mechanisms explaining these findings remain unclear, CCR5 ligand-mediated activation of T cells, macrophages, and neutrophils via alternative chemokine receptors should be explored. These results may have relevance for trials of maraviroc for HIV preexposure prophylaxis and graft-versus-host disease. This trial was registered at www.clinicaltrials.gov as #NCT00735072.

ADAM-10 is overexpressed in rheumatoid arthritis synovial tissue and mediates angiogenesis

OBJECTIVE

To examine the expression of ADAM-10 in rheumatoid arthritis (RA) synovial tissue (ST) and the role it plays in angiogenesis.

METHODS

ADAM-10 expression was determined using immunohistology, Western blotting, and quantitative polymerase chain reaction. In order to examine the role of ADAM-10 in angiogenesis, we performed in vitro Matrigel tube formation and chemotaxis assays using human microvascular endothelial cells (HMVECs) transfected with control or ADAM-10 small interfering RNA (siRNA). To determine whether ADAM-10 plays a role in angiogenesis in the context of RA, we performed Matrigel assays using a coculture system of HMVECs and RA synovial fibroblasts.

RESULTS

Endothelial cells and lining cells within RA ST expressed high levels of ADAM-10 compared with cells within osteoarthritis ST and normal ST. ADAM-10 expression was significantly elevated at the protein and messenger RNA levels in HMVECs and RA synovial fibroblasts stimulated with proinflammatory mediators compared with unstimulated cells. ADAM-10 siRNA-treated HMVECs had decreased endothelial cell tube formation and migration compared with control siRNA-treated HMVECs. In addition, ADAM-10 siRNA-treated HMVECs from the RA synovial fibroblast coculture system had decreased endothelial cell tube formation compared with control siRNA-treated HMVECs.

CONCLUSION

These data show that ADAM-10 is overexpressed in RA and suggest that ADAM-10 may play a role in RA angiogenesis. ADAM-10 may be a potential therapeutic target in inflammatory angiogenic diseases such as RA.

Influence of sensitization and allergen provocation procedures on the development of allergen-induced bronchial hyperreactivity in conscious, unrestrained guinea-pigs

The effects of different sensitization and allergen provocation regimens on the development of allergen-induced bronchial hyperreactivity (BHR) to histamine were investigated in conscious, unrestrained guinea-pigs. Similar early and late phase asthmatic reactions, BHR for inhaled histamine after the early (6 h) as well as after the late reaction (24 h), and airway inflammation were observed after a single allergen provocation in animals sensitized to produce mainly IgG or IgE antibodies, respectively. Repeating the allergen provocation in the IgE-sensitized animals after 7 days, using identical provocation conditions, resulted in a similar development of BHR to histamine inhalation. Repetition of the allergen provocation during 4 subsequent days resulted in a decreased development of BHR after each provocation, despite a significant increase in the allergen provocation dose necessary to obtain similar airway obstruction. The number of inflammatory cells in the bronchoalveolar lavage was not significantly changed after repeated provocation, when compared with a single allergen provocation. Finally, we investigated allergen-induced bronchial hyperreactivity by repetition of the sensitization procedure at day 7 and 14 (booster), followed by repeated allergen provocation twice a week for 5 weeks. Surprisingly, no BHR to histamine could be observed after either provocation, while the number of inflammatory cells in the bronchoalveolar lavage fluid after 5 weeks was enhanced compared with controls. These data indicate that both IgE and IgG sensitized guinea-pigs may develop bronchial hyperreactivity after a single allergen provocation. Repeated allergen exposure of IgE sensitized animals causes a gradual fading of the induced hyperreactivity despite the on-going presence of inflammatory cells in the airways, indicating a mechanism of reduced cellular activation.

Androgen metabolism and inhibition of interleukin-1 synthesis in primary cultured human synovial macrophages

The presence of androgen receptors on synovial macrophages in human normal and rheumatoid synovial tissues has been described previously. It is now reported that primary cultured human macrophages obtained from normal and rheumatoid synovia express functional androgen receptors. We have investigated the capacity of cultured macrophages to metabolize androgens and have found that these cells were capable of metabolizing testosterone to the bioactive metabolite dihydrotestosterone. Therefore, macrophages contain the key enzymes of steroidogenesis, in particular the 5α-treductase. Furthermore, interleukin-1β production by primary cultured rheumatoid macrophages was analysed, following exposure to physiological concentrations of testosterone (10⁻⁸ M). A significant decrease of IL-1β levels in conditioned media after 24 h (p < 0.05) was observed. It is concluded that androgens may act directly on human macrophages and may interfere with some of their functions via receptor-dependent mechanisms.

RANTES, MCP-1 chemokines and factors describing rheumatoid arthritis

The MCP-1/CCL2 as well as RANTES/CCL5 chemokines are potent chemoattractants involved in immunoregulatory and inflammatory processes of rheumatoid arthritis. Recent studies demonstrated elevated levels of MCP-1 and RANTES in plasma, synovial fluid, and the synovial tissue of patients with RA. To examine the relationship among MCP-1 and RANTES single nucleotide polymorphisms and circulating levels and rheumatoid arthritis (RA), a total of 156 RA patients and 125 controls were recruited into the study. An association of -855 C/G MCP-1 polymorphism to IgM RF within the RA patients was observed. The lowest circulating levels of RANTES were observed in the AA variant of RANTES -403 G/A polymorphism. Furthermore, an association of -403 AA variant to circulating levels of IL-15 and IL-10 was found. No associations of factors describing rheumatoid arthritis (RFs, ANA, anti-CCP-positive/negative, DAS 28 score and number of swollen joints) with MCP-1 levels, genotype distribution, allelic frequencies and/or frequencies of haplotypes composed of all three studied polymorphisms in promoter region of MCP-1, and RANTES polymorphism were observed. We conclude that the RANTES promoter polymorphism is associated to circulating levels of RANTES, IL15 and IL10. However, our findings suggest that polymorphisms in the MCP-1 and RANTES gene promoters do not contribute significantly to the interindividual RA susceptibility and/or severity in Caucasians.

Exacerbation of collagen induced arthritis by Fcγ receptor targeted collagen peptide due to enhanced inflammatory chemokine and cytokine production

Antibodies specific for bovine type II collagen (CII) and Fcγ receptors play a major role in collagen-induced arthritis (CIA), a mouse model of rheumatoid arthritis (RA). Our aim was to clarify the mechanism of immune complex-mediated inflammation and modulation of the disease. CII pre-immunized DBA/1 mice were intravenously boosted with extravidin coupled biotinylated monomeric CII-peptide epitope (ARGLTGRPGDA) and its complexes with biotinylated FcγRII/III specific single chain Fv (scFv) fragment. Disease scores were monitored, antibody titers and cytokines were determined by ELISA, and binding of complexes was detected by flow cytometry and immune histochemistry. Cytokine and chemokine secretion was monitored by protein profiler microarray. When intravenously administered into collagen-primed DBA/1 mice, both CII-peptide and its complex with 2.4G2 scFv significantly accelerated CIA and increased the severity of the disease, whereas the monomeric peptide and monomeric 2.4G2 scFv had no effect. FcγRII/III targeted CII-peptide complexes bound to marginal zone macrophages and dendritic cells, and significantly elevated the synthesis of peptide-specific IgG2a. Furthermore, CII-peptide containing complexes augmented the in vivo secretion of cytokines, including IL-10, IL-12, IL-17, IL-23, and chemokines (CXCL13, MIP-1, MIP-2). These data indicate that complexes formed by the CII-peptide epitope aggravate CIA by inducing the secretion of chemokines and the IL-12/23 family of pro-inflammatory cytokines. Taken together, these results suggest that the in vivo emerging immune complexes formed with autoantigen(s) may trigger the IL-12/23 dependent pathways, escalating the inflammation in RA. Thus blockade of these cytokines may be beneficial to downregulate immune complex-induced inflammation in autoimmune arthritis.

CGS 21680, an agonist of the adenosine (A2A) receptor, reduces progression of murine type II collagen-induced arthritis

OBJECTIVE

The aim of our study was to investigate the effect of an adenosine A2A receptor agonist, 2-[p-(2-carboxyethyl)phenylethylamino]-50 ethylcarboxamidoadenosine (CGS 21680), on modulation of the inflammatory response in mice subjected to collagen-induced arthritis (CIA).

METHODS

CIA was induced by intradermal injection of 100 μl of emulsion containing 100 μg of bovine type II collagen (CII) and complete Freund's adjuvant (CFA) at the base of the tail. On Day 21, a second injection of CII in CFA was administered. Immunized mice developed erosive hind paw arthritis. Macroscopic clinical evidence of CIA first appeared as periarticular erythema and edema in the hind paws. The incidence of CIA was 100% by Day 27 in the CII challenged mice and the severity of CIA progressed over a 35-day period, with radiographic evaluation revealing focal resorption of bone. The histopathology of CIA included erosion of cartilage at the joint margins.

RESULTS

Treatment of mice with CGS 21680 starting at the onset of arthritis (Day 25) ameliorated the clinical signs at Days 26-35 and improved histological status in the joint and paw. The degree of oxidative and nitrosative damage was significantly reduced in CGS 21680-treated mice as indicated by elevated levels of malondialdehyde, formation of nitrotyrosine, and activation of poly(ADP-ribose) polymerase. Plasma levels of proinflammatory cytokines such as tumor necrosis factor, interleukin 1ß (IL-1ß) and IL-6 were also reduced by CGS 21680. Treatment with CGS 21680 also decreased the expression of inducible nitric oxide synthase and cyclooxygenase-2.

CONCLUSION

We demonstrate that CGS 21680 exerts an antiinflammatory effect during chronic inflammation and ameliorates the tissue damage associated with CIA.

Why CCR2 and CCR5 blockade failed and why CCR1 blockade might still be effective in the treatment of rheumatoid arthritis

Background

The aim of this study was to provide more insight into the question as to why blockade of CCR1, CCR2, and CCR5 may have failed in clinical trials in rheumatoid arthritis (RA) patients, using an in vitro monocyte migration system model.

Methodology/Principal Findings

Monocytes from healthy donors (HD; n = 8) or from RA patients (for CCR2 and CCR5 antibody n = 8; for CCR1 blockade n = 13) were isolated from peripheral blood and pre-incubated with different concentrations of either anti-CCR1, anti-CCR2, or anti-CCR5 blocking antibodies (or medium or isotype controls). In addition, a small molecule CCR1 antagonist (BX471) was tested. Chemotaxis was induced by CCL2/MCP-1 (CCR2 ligand), CCL5/RANTES (CCR1 and CCR5 ligand), or by a mix of 5 RA synovial fluids (SFs), and cellular responses compared to chemotaxis in the presence of medium alone. Anti-CCR2 antibody treatment blocked CCL2/MCP-1-induced chemotaxis of both HD and RA monocytes compared to isotype control. Similarly, anti-CCR5 antibody treatment blocked CCL5/RANTES-induced chemotaxis of RA monocytes. While neither CCR2 nor CCR5 blocking antibodies were able to inhibit SF-induced monocyte chemotaxis, even when both receptors were blocked simultaneously, both anti-CCR1 antibodies and the CCR1 antagonist were able to inhibit SF-induced monocyte chemotaxis.

Conclusions/Significance

The RA synovial compartment contains several ligands for CCR1, CCR2, and CCR5 as well as other chemokines and receptors involved in monocyte recruitment to the site of inflammation. The results suggest that CCR2 and CCR5 are not critical for the migration of monocytes towards the synovial compartment in RA. In contrast, blockade of CCR1 may be effective. Conceivably, CCR1 blockade failed in clinical trials, not because CCR1 is not a good target, but because very high levels of receptor occupancy at all times may be needed to inhibit monocyte migration in vivo.

Effect of a phytotherapeutic agent, Eviprostat®, on prostatic and urinary cytokines/chemokines in a rat model of nonbacterial prostatitis

BACKGROUND

Chronic inflammation in the prostate has recently been recognized as an important component of the symptom progression of benign prostatic hyperplasia. The objective of this study was to evaluate a range of cytokines/chemokines in prostate tissue and urine to identify markers of prostate inflammation in a prostatitis model and to investigate the effect of a phytotherapeutic agent, Eviprostat®, on these markers.

METHODS

Ten-month-old male Wistar rats were divided into four groups. Nonbacterial prostatitis (NBP) was experimentally induced in groups 2-4 by castration followed by daily subcutaneous injection of 17β-estradiol for 30 days. Control rats were fed a standard diet, while animals in the Eviprostat groups were fed a diet containing 0.05 or 0.1% Eviprostat for 30 days. The levels of cytokines/chemokines in prostate tissue on the 31st day and in urine collected the day before castration and the day before removal of the prostate were determined.

RESULTS

Experimentally induced NBP increased the prostatic levels of the cytokines interleukin-1β (IL-1β) and tumor necrosis factor-α (TNF-α). The levels of the chemokines CCL2/monocyte chemoattractant protein-1 (MCP-1), CCL3/macrophage inflammatory protein-1α (MIP-1α), CXCL1/CINC-1, CXCL3/CINC-2, and CXCL5/LIX were elevated in both prostate and urine. Eviprostat significantly suppressed the increases in prostate IL-1β, TNF-α and CCL3/MIP-1α and prostatic and urinary CCL2/MCP-1 and CXCL1/CINC-1.

CONCLUSIONS

Chemokines, including CCL2/MCP-1 and CXCL1/CINC-1, were elevated in the prostate and urine of NBP rats, and Eviprostat potently suppressed the increases in CCL2/MCP-1 and CXCL1/CINC-1. These chemokines are therefore candidate diagnostic biomarkers for nonbacterial chronic prostatic inflammation.

Pan-CC chemokine neutralization restricts splenocyte egress and reduces inflammation in a model of arthritis

Chemokines are key regulators of leukocyte trafficking and play a crucial role under homeostatic and inflammatory conditions. Because chemokines are involved in multiple pathologies, they represent an attractive class of therapeutic targets. However, because of the redundancy of this system, neutralizing a single chemokine may be insufficient to achieve therapeutic benefit. Our strategy was to use a Fc-fusion recombinant protein form of the poxvirus-derived viral CC chemokine inhibitor protein (vCCI-Fc) that has the ability to specifically bind to multiple CC chemokines and neutralize their activity. In this study, we demonstrate first that, in vivo, vCCI-Fc prevents CC chemokine-dependent migration of macrophages into inflamed tissue of carageenan-challenged mice. We next studied this effect of inhibiting CC chemokine activity in a model more relevant to human disease, collagen-induced arthritis. Mice receiving vCCI-Fc revealed a striking retention of splenocytes, including activated and IFN-gamma-secreting CD4(+) and CD8(+) T cells, that was associated with a concomitant decrease of cells in the draining lymph nodes. These phenomena resulted in a significant decrease in the incidence of disease and a reduction in clinical score, joint inflammation, and cartilage destruction as compared with mice receiving isotype control. Taken together, these results define a role for CC chemokines in the control of disease, as interfering with their function leads to a previously unappreciated role of controlling inflammatory cell trafficking in and out of secondary lymphoid organs.

Bim-Bcl-2 homology 3 mimetic therapy is effective at suppressing inflammatory arthritis through the activation of myeloid cell apoptosis

OBJECTIVE

Rheumatoid arthritis (RA) is a destructive autoimmune disease characterized by an increased inflammation in the joint. Therapies that activate the apoptotic cascade may have potential for use in RA; however, few therapeutic agents fit this category. The purpose of this study was to examine the potential of Bim, an agent that mimics the action of Bcl-2 homology 3 (BH3) domain-only proteins that have shown success in preclinical studies of cancer, in the treatment of autoimmune disease.

METHODS

Synovial tissues from RA and osteoarthritis patients were analyzed for the expression of Bim and CD68 using immunohistochemistry. Macrophages from Bim(-/-) mice were examined for their response to lipopolysaccharide (LPS) using flow cytometry, real-time polymerase chain reaction analysis, enzyme-linked immunosorbent assay, and immunoblotting. Bim(-/-) mice were stimulated with thioglycollate or LPS and examined for macrophage activation and cytokine production. Experimental arthritis was induced using the K/BxN serum-transfer model. A mimetic peptide corresponding to the BH3 domain of Bim (TAT-BH3) was administered as a prophylactic agent and as a therapeutic agent. Edema of the ankles and histopathologic analysis of ankle tissue sections were used to determine the severity of arthritis, its cellular composition, and the degree of apoptosis.

RESULTS

The expression of Bim was reduced in RA synovial tissue as compared with controls, particularly in macrophages. Bim(-/-) macrophages displayed elevated expression of markers of inflammation and secreted more interleukin-1beta following stimulation with LPS or thioglycollate. TAT-BH3 ameliorated arthritis development, reduced the number of myeloid cells in the joint, and enhanced apoptosis without inducing cytotoxicity.

CONCLUSION

These data demonstrate that BH3 mimetic therapy may have significant potential for the treatment of RA.

Chemokines and chemokine receptors in arthritis

Chemokines are involved in leukocyte recruitment to inflammatory sites, such as the synovial tissue in rheumatoid arthritis (RA). There is a structural and a functional classification of chemokines. The former includes four groups: CXC, CC, C and CX3C chemokines. Chemokines may also be either inflammatory or homeostatic, however, these functions often overlap. Anti-chemokine and anti-chemokine receptor targeting may be therapeutically used in the future biological therapy of arthritis. Most data in this field have been obtained from animal models of arthritis as only very few human RA trials have been completed. However, it is very likely that various specific chemokine and chemokine receptor antagonists will be developed and administered to RA patients.

CCR5 is involved in resolution of inflammation in proteoglycan-induced arthritis

OBJECTIVE

CCR5 and its ligands (CCL3, CCL4, and CCL5) may play a role in inflammatory cell recruitment into the joint. However, it was recently reported that CCR5 on T cells and neutrophils acts as a decoy receptor for CCL3 and CCL5 to assist in the resolution of inflammation. The aim of this study was to determine whether CCR5 functions as a proinflammatory or antiinflammatory mediator in arthritis, by examining the role of CCR5 in proteoglycan (PG)-induced arthritis (PGIA).

METHODS

Arthritis was induced by immunizing wild-type (WT) and CCR5-deficient (CCR5(-/-)) BALB/c mice with human PG in adjuvant. The onset and severity of PGIA were monitored over time. Met-RANTES was used to block CCR5 in vivo. Arthritis was transferred to SCID mice, using spleen cells from arthritic WT and CCR5(-/-) mice. The expression of cytokines and chemokines was measured by enzyme-linked immunosorbent assay.

RESULTS

In CCR5(-/-) mice and WT mice treated with the CCR5 inhibitor Met-RANTES, exacerbated arthritis developed late in the disease course. The increase in arthritis severity in CCR5(-/-) mice correlated with elevated serum levels of CCL5. However, exacerbated arthritis was not intrinsic to the CCR5(-/-) lymphoid cells, because the arthritis that developed in SCID mouse recipients was similar to that in WT and CCR5(-/-) mice. CCR5 expression in the SCID mouse was sufficient to clear CCL5, because serum levels of CCL5 were the same in SCID mouse recipients receiving cells from either WT or CCR5(-/-) mice.

CONCLUSION

These data demonstrate that CCR5 is a key player in controlling the resolution of inflammation in experimental arthritis.

An arrestin-dependent multi-kinase signaling complex mediates MIP-1beta/CCL4 signaling and chemotaxis of primary human macrophages

MIP-1beta/CCL4 is a principal regulator of macrophage migration and signals through CCR5. Several protein kinases are linked to CCR5 in macrophages including the src kinase Lyn, PI3K, focal adhesion related kinase Pyk2, and members of the MAPK family, but whether and how these kinases regulate macrophage chemotaxis are not known. To define the role of these signaling molecules, we examined the functions and interactions of endogenous proteins in primary human macrophages. Using siRNA gene silencing and pharmacologic inhibition, we show that chemotaxis in response to CCR5 stimulation by MIP-1beta requires activation of Pyk2, PI3K p85, and Lyn, as well as MAPK ERK. MIP-1beta activation of CCR5 triggered translocation of Pyk2 and PI3K p85 from the cytoplasm to colocalize with Lyn at the plasma membrane with formation of a multimolecular complex. We show further that arrestins were recruited into the complex, and arrestin down-regulation impaired complex formation and macrophage chemotaxis toward MIP-1beta. Together, these results identify a novel mechanism of chemokine receptor regulation of chemotaxis and suggest that arrestins may serve as scaffolding proteins linking CCR5 to multiple downstream signaling molecules in a biologically important primary human cell type.

The role of chemokines in rheumatoid arthritis and osteoarthritis

The directed movement of immune cells is highly dependent on the chemokine network. Chemokines are key molecules early in the embryogenesis of lymph nodes and throughout adult life, where they regulate immune responses against pathogens. Although immune cells are best known for expressing chemokine receptors, through which they can respond to matching chemokines, endothelial cells also express chemokine receptors. The directed movement of endothelial cells facilitates angiogenesis. In chronic inflammatory conditions, such as rheumatoid arthritis (RA), chemokines are abundantly present at the site of inflammation and form a group of potential therapeutic targets. Some agents that block chemokine-chemokine receptor interaction are already under clinical investigation. The expression of chemokine receptors has also been found in cell types other than immune cells and endothelial cells. Chondrocytes, for instance, express several chemokine receptors. Elucidating their function may provide new insights into joint degradation in RA as well as in other conditions, including osteoarthritis (OA).

Inhalation of carbon monoxide ameliorates collagen-induced arthritis in mice and regulates the articular expression of IL-1beta and MCP-1

Carbon monoxide (CO), long considered a toxic gas, has recently been shown to mediate anti-inflammatory effects in various animal models. The aim of this study was to investigate whether the inhalation of CO ameliorated collagen-induced arthritis (CIA) in mice. CIA was induced in female DBA/1 mice by the injection of an anti-type II collagen antibody and lipopolysaccharide. The CO treatment group was exposed to CO gas at a concentration of 200 ppm in a closed cage starting on the day of the injection with an anti-type II collagen antibody and throughout the remaining study period. The clinical arthritis scores was examined daily for swelling of the paws as a sign of arthritis. For histopathology, the sections of the hind legs were evaluated by hematoxylin-eosin staining. Moreover, we evaluated the expression of interleukin (IL)-1beta and monocyte chemoattractant protein-1 (MCP-1) mRNA in the hind paws. Both clinical arthritis scores as well as histological findings of joint inflammation were significantly reduced in mice treated with CO gas inhalation compared to untreated mice. Further, CO significantly inhibited the increased expression of IL-1beta and MCP-1 mRNA in paws at day 3 after the induction of arthritis. In conclusion, the inhalation of CO protected mice from the synovial inflammation of CIA. Based on these data, the beneficial effects of CO in murine RA model may be attributed to its anti-inflammatory properties.

Etanercept reduces the serum levels of macrophage chemotactic protein-1 in patients with rheumatoid arthritis

This study was performed to analyze the effect of etanercept, the soluble tumor necrosis factor-alpha (TNF-alpha) receptor, on the serum levels of several chemokines including monocyte chemotactic protein-1 (MCP-1), regulated upon activation normal T expressed and presumably secreted (RANTES), and granzyme B in rheumatoid arthritis (RA) patients. Twenty-eight patients with RA were administered etanercept once or twice a week for more than 6 months. Clinical and laboratory parameters were measured and serum levels of MCP-1, RANTES, and granzyme B were determined using enzyme-linked immunosorbent assay (ELISA) kits at baseline and at 3 and 6 months after the initial treatment. In addition, the levels of MCP-1, RANTES, and granzyme B produced by cultured synovial cells stimulated with TNF-alpha were measured. A significant decrease in serum MCP-1 levels was observed at 3 and 6 months after initial treatment with etanercept. Serum RANTES and granzyme B levels did not show significant changes. TNF-alpha induced MCP-1, RANTES, and granzyme B production in cultured synovial cells from RA patients. Serum MCP-1 levels were significantly correlated with the disease activity scores of 28 joints combined with CRP (DAS28-CRP), indicating the role of MCP-1 in the pathogenesis of rheumatoid inflammation. This study demonstrated that a reduction of MCP-1 production in RA patients was a newly determined effect of etanercept. Another cascade not associated with TNF-alpha may induce granzyme B and RANTES production in RA patients.

Peripheral blood T4 cell surface CCR5 density as a marker of activity in rheumatoid arthritis treated with anti-CD20 monoclonal antibody

The chemokine (C-C motif) receptor CCR5 and its ligand CCL5 play key roles in the intra-articular recruitment of peripheral blood mononuclear cells (PBMC) in rheumatoid arthritis (RA). Therefore, using quantitative cytofluorometry, we followed T4 cell surface CCR5 density in 27 subjects with RA before and after treatment with the anti-CD20 monoclonal antibody rituximab. We observed low T4 cell surface CCR5 densities before treatment, which correlated positively with disease activity, as determined using a disease activity score evaluated on 28 joints (DAS 28), and negatively with CCL5 mRNA concentrations in PBMC, contrasting with a high proportion of intracellular CCR5 molecules, a pattern compatible with ligand-induced CCR5 internalization. At 3 months post-treatment, CCL5 mRNA expression in PBMC declined, whereas T4 cell surface CCR5 densities increased proportionally to the decrease in DAS 28. Thus, peripheral blood T4 cell surface CCR5 density is a good surrogate marker of RA activity and of the efficiency of anti-CD20 therapy.

Suppression of Tie-1 in endothelial cells in vitro induces a change in the genome-wide expression profile reflecting an inflammatory function

Tie-1 is an endothelial specific receptor tyrosine kinase that is upregulated in diseases such as atherosclerosis and rheumatoid arthritis. We recently demonstrated that Tie-1 induced a proinflammatory response when overexpressed in endothelial cells. Here, we used a complementary approach and suppressed endogenous Tie-1 expression in endothelial cells to examine its function by microarray analysis. Tie-1 appeared to govern expression of many genes involved in inflammation. Expression knockdown of Tie-1 significantly reduced endothelial conditioned medium ability to stimulate MCP-1 production in U937 cells. Collectively, our results support the notion that Tie-1 has an inflammatory function in endothelial cells.

Exuberant expression of chemokine genes by adult human articular chondrocytes in response to IL-1beta

OBJECTIVE

To provide a more complete picture of the effect of interleukin-1 beta (IL-1beta) on adult human articular chondrocyte gene expression, in contrast to the candidate gene approach.

DESIGN

Chondrocytes from human knee cartilage were cultured in medium containing IL-1beta. Changes in gene expression were analyzed by microarray and reverse transcriptase-polymerase chain reaction analysis. The ability of transforming growth factor beta-1 (TGF-beta1), fibroblast growth factor (FGF)-18, and bone morphogenetic protein 2 (BMP-2) to alter the effects of IL-1beta was analyzed. Computational analysis of the promoter regions of differentially expressed genes for transcription factor binding motifs was performed.

RESULTS

IL-1beta-treated human chondrocytes showed significant increases in the expression of granulocyte colony stimulating factor-3, endothelial leukocyte adhesion molecule 1 and leukemia inhibitory factor as well as for a large group of chemokines that include CXCL1, CXCL2, CXCL3, CXCL5, CXCL6, CXCL8, CCL2, CCL3, CCL4, CCL5, CCL8, CCL20, CCL3L1, CX3CL1 and the cytokine IL-6. As expected, the mRNA for matrix metalloproteinase (MMP)-13 and BMP-2 also increased while mRNA for the matrix genes COL2A1 and aggrecan was down-regulated. A subset of chemokines increased rapidly at very low levels of IL-1beta. The phenotype induced by IL-1beta was partially reversed by TGF-beta1, but not by BMP-2. In the presence of IL-1beta, FGF-18 increased expression of ADAMTS-4, aggrecan, BMP-2, COL2A1, CCL3, CCL4, CCL20, CXCL1, CXCL3, CXCL6, IL-1beta, IL-6, and IL-8 and decreased ADAMTS-5, MMP-13, CCL2, and CCL8. Computational analysis revealed a high likelihood that the most up-regulated chemokines are regulated by the transcription factors myocyte enhancer binding factor-3 (MEF-3), CCAAT/enhancer binding protein (C/EBP) and nuclear factor-kappa B (NF-kappaB).

CONCLUSION

IL-1beta has a diverse effect on gene expression profile in human chondrocytes affecting matrix genes as well as chemokines and cytokines. TGF-beta1 has the ability to antagonize some of the phenotype induced by IL-1beta.

H-2g, a glucose analog of blood group H antigen, mediates mononuclear cell recruitment via Src and phosphatidylinositol 3-kinase pathways

OBJECTIVE

Monocyte recruitment by proinflammatory cytokines is a hallmark of rheumatoid arthritis (RA). Lewis(y-6) and H (Le(y)/H) are blood group antigens up-regulated on RA synovial endothelium. We have previously shown that both soluble Le(y)/H and a glucose analog of H, H-2g, are angiogenic and mediateleukocyte-endothelial adhesion via induction of intercellular adhesion molecule 1. We hypothesized that soluble Le(y)/H plays an important role in monocyte recruitment in RA.

METHODS

We examined the role of H-2g in monocyte chemotaxis in vitro. We used an RA synovial tissue (ST)-SCID mouse chimera model to evaluate the role of H-2g in monocyte recruitment in vivo. We used Western blots to examine signaling molecules activated by H-2g in monocytes.

RESULTS

H-2g induced human monocyte migration in vitro, which was mediated by Src and phosphatidylinositol 3-kinase (PI 3-kinase), since inhibitors and antisense oligodeoxynucleotides (ODNs) of Src and PI 3-kinase significantly decreased H-2g-induced monocyte migration (P < 0.05). H-2g significantly increased mononuclear cell (MNC) homing in vivo into an RA ST-SCID mouse chimera (P < 0.05). Transfection of MNCs with Src antisense ODNs blocked H-2g-induced MNC recruitment into the RA ST-SCID mouse chimera. Additionally, H-2g induced marked phosphorylation of protein kinase CalphaI/betaII (PKCalphaI/betaII), Src, IkappaBalpha, and Akt in monocytes. Src, Akt, and NF-kappaB were shown to be downstream targets of PKCalphaI/betaII, since an inhibitor of PKCalphaI/betaII reduced H-2g-mediated phosphorylation of Src, Akt, and NF-kappaB in monocytes.

CONCLUSION

These data suggest that H-2g may be a novel mediator of monocyte recruitment in chronic inflammatory diseases like RA.

Cells of the synovium in rheumatoid arthritis. Dendritic cells

Dendritic cells are the major antigen-presenting and antigen-priming cells of the immune system. We review the antigen-presenting and proinflammatory roles played by dendritic cells in the initiation of rheumatoid arthritis (RA) and atherosclerosis, which complicates RA. Various signals that promote the activation of NF-κB and the secretion of TNF and IL-1 drive the maturation of dendritic cells to prime self-specific responses, and drive the perpetuation of synovial inflammation. These signals may include genetic factors, infection, cigarette smoking, immunostimulatory DNA and oxidized low-density lipoprotein, with major involvement of autoantibodies. We propose that the pathogenesis of RA and atherosclerosis is intimately linked, with the vascular disease of RA driven by similar and simultaneous triggers to NF-κB.

Monocyte chemoattractant protein-1 and macrophage inflammatory protein-1alpha as possible biomarkers for the chronic pelvic pain syndrome

PURPOSE

The chronic pelvic pain syndrome is characterized by pelvic pain, voiding symptoms and varying degrees of inflammation within expressed prostatic secretions. We evaluated the chemokines monocyte chemoattractant protein 1 (CCL2) and macrophage inflammatory protein-1alpha (CCL3) in expressed prostatic secretions to identify marker increases associated with inflammatory (IIIA) and noninflammatory (IIIB) chronic pelvic pain syndrome. In addition, chemokine levels were correlated with clinical pain as determined by the National Institutes of Health chronic prostatitis symptom index.

MATERIALS AND METHODS

Expressed prostatic secretions were collected by digital rectal examination, and evaluated by enzyme linked immunosorbent assays for monocyte chemoattractant protein 1 and macrophage inflammatory protein-1alpha in 154 patients including controls (13), those with benign prostatic hyperplasia (54), chronic pelvic pain syndrome IIIA (37) and IIIB (50). Monocyte chemoattractant protein 1 and macrophage inflammatory protein-1alpha levels were compared between IIIA, IIIB and the control subgroups, and correlated against the chronic prostatitis symptom index and pain subscore using a Spearman test.

RESULTS

Mean levels of monocyte chemoattractant protein 1 in the control, inflammatory benign prostatic hyperplasia, noninflammatory benign prostatic hyperplasia, inflammatory chronic pelvic pain syndrome and noninflammatory chronic pelvic pain syndrome were 599.4, 886.0, 1,636.5, 3,261.2 and 2,272.7 pg/ml, respectively. Mean levels of macrophage inflammatory protein-1alpha in the control, inflammatory benign prostatic hyperplasia, noninflammatory benign prostatic hyperplasia, IIIA chronic pelvic pain syndrome and IIIB chronic pelvic pain syndrome were 140.1, 299.4, 238.7, 1,057.8 and 978.4 pg/ml, respectively. For each cytokine both chronic pelvic pain syndrome subtypes had statistically higher levels than the control group and patients with benign prostatic hyperplasia (p = 0.0002). Receiver operating curves using monocyte chemoattractant protein 1 levels greater than 704 pg/ml and macrophage inflammatory protein-1alpha greater than 146 pg/ml identified patients with chronic pelvic pain syndrome with an accuracy of 90% from control patients. Macrophage inflammatory protein-1alpha levels (p = 0.0007) correlated with the pain subscore of the chronic prostatitis symptom index while monocyte chemoattractant protein 1 (p = 0.71) did not.

CONCLUSIONS

Monocyte chemoattractant protein 1 and macrophage inflammatory protein-1alpha within the prostatic fluid in both chronic pelvic pain syndrome subtypes provide candidate future biomarkers for chronic pelvic pain syndrome. In addition, macrophage inflammatory protein-1alpha increase in expressed prostatic secretions provides a new marker for clinical pain in chronic pelvic pain syndrome patients. Given these findings prostatic dysfunction likely has a role in the pathophysiology of this syndrome. These chemokines may serve as effective diagnostic markers and modulators against the chemokines could provide an attractive treatment strategy in individuals with chronic pelvic pain syndrome.

Phase I evaluation of the safety, pharmacokinetics and pharmacodynamics of CP-481,715

BACKGROUND AND OBJECTIVES

The chemokine receptor CCR1 is believed to play a role in several inflammatory diseases, primarily by promoting the migration of leukocytes through the endothelial barrier. Thus, a possible strategy for treating inflammatory diseases is inhibition of leukocyte infiltration by antagonising CCR1. Recently, CP-481,715 has been described as a potent and specific antagonist of CCR1. The aims of this study were to assess the safety, pharmacokinetics and pharmacodynamics of CP-481,715 along with drug interactions with ciclosporin.

SUBJECTS AND METHODS

This was a phase I randomised, double-blind, placebo-controlled study with CP-481,715 in 78 healthy male volunteers. Subjects were administered escalating CP-481,715 doses of up to 3000 mg with food and after fasting in the single-dose study. In the drug interaction study, which was a single-dose, two-way crossover study, 12 subjects received a 300 mg dose of CP-481,715 as a suspension of polymorph A under fasted conditions, both with and without prior administration of ciclosporin.

RESULTS AND CONCLUSIONS

All doses of CP-481,715 were well tolerated, with linear pharmacokinetics up to the 300 mg dose. The pharmacodynamic activity of CP-481,715 was detected ex vivo by demonstrating a dose-related and linear increase in the amount of macrophage inflammatory protein-1alpha, CCL3, required to induce CD11b upregulation. Analysis of vital signs indicated no consistent clinical effects, and statistical analysis of ECG characteristics demonstrated no significant prolongation of the corrected QT interval. A drug-drug interaction study with ciclosporin demonstrated that CP-481,715 clearance was decreased by ciclosporin, consistent with its ability to compete with P-glycoprotein. Phase II studies may be warranted to see if CP-481,715 exhibits efficacy in treating inflammatory diseases such as rheumatoid arthritis, multiple sclerosis or transplant rejection.

Negative association between the chemokine receptor CCR5-Delta32 polymorphism and rheumatoid arthritis: a meta-analysis

Rheumatoid arthritis (RA) is characterized by synovial inflammation mediated by T-cells, monocytes and macrophages. The homing of these cells to the inflamed synovium is regulated by chemokine-receptors and their ligands. A 32-basepair deletion (Delta32) in the gene encoding CCR5, a chemokine-receptor, results in a non-functional receptor. A negative association between CCR5-Delta32 and RA has been described, although other studies found no associations. Furthermore, the observation that individuals homozygous for CCR5-Delta32 develop RA has raised questions about the role of CCR5-Delta32. This meta-analysis of all published case-control association studies confirms the negative association between CCR5-Delta32 and RA (Odds Ratio=0.65; 95% confidence intervals=0.55-0.77; P<0.0001), suggesting that CCR5-Delta32 is protective against the development of RA. CCR5 blockade in animal models of RA results in amelioration of arthritis, suggesting that CCR5 blockade could also modify disease in patients with RA.

Cell surface CCR5 density determines the intensity of T cell migration towards rheumatoid arthritis synoviocytes

As we have recently shown that the number of CCR5 molecules at the cell surface determines the efficiency of its function as a chemokine receptor, we tested the hypothesis that cell surface CCR5 density could influence the intensity of T lymphocyte recruitment into the rheumatoid joint. For this purpose, we established two Jurkat cell line-derived clones that differed only by their cell surface CCR5 densities. We studied their chemotaxis towards TNF-alpha-transduced rheumatoid synoviocytes supernatant. The Jurkat cell subline that expressed the higher cell surface CCR5 density migrated more intensively towards the supernatant of TNF-alpha-transduced synoviocytes than the Jurkat cell subline that expressed a lower surface CCR5 density. Moreover, this migration was blocked by an anti-CCR5 mAb. The CCR5 density on T cell surface, which is constant over time for a given individual, but varies drastically from one individual to another, might thus be a factor determining the intensity of joint inflammation in the course of RA.

Prothymosin α Lacking the Nuclear Localization Signal as an Effective Gene Therapeutic Strategy in Collagen-Induced Arthritis

Prothymosin alpha (ProT) is regulated by c-Myc, an oncoprotein overexpressed in synovium of rheumatoid arthritis, and is associated with cell proliferation. However, ProT also exerts immunomodulatory activities. The growth-promoting activity of ProT can be abolished by deleting its nuclear localization signal (NLS). In this study, we showed that AdProTDeltaNLS, an adenoviral vector encoding ProT lacking the NLS, did not enhance the proliferation of synovial fibroblasts. AdProTDeltaNLS treatment abolished the up-regulation of the MIP-1alpha promoter activity induced by TNF-alpha in synovial fibroblasts. AdProTDeltaNLS suppressed macrophage chemotaxis and reduced macrophage infiltration into the ankle joints in rats with collagen-induced arthritis (CIA). Neutralization test confirmed the involvement of MIP-1alpha in macrophage chemotaxis. Administration of AdProTDeltaNLS reduced the severity of CIA in the clinical, radiographic, and histological aspects. The levels of TNF-alpha (mean +/- SEM, 1261.9 +/- 107.9 vs 2880.1 +/- 561.4 pg/mg total protein; p < 0.05), IL-1beta (56.8 +/- 8.0 vs 109.2 +/- 4.9 pg/mg total protein; p < 0.01), and MIP-1alpha (41.7 +/- 3.6 vs 55.2 +/- 1.1 pg/mg total protein; p < 0.05) in the ankle joints were lower in the AdProTDeltaNLS-treated rats with CIA than those in their control counterparts. In the AdProTDeltaNLS-treated ankle joints, matrix metalloproteinase-9 expression was decreased by 40% and infiltrating macrophages reduced by 50%. Our results demonstrate that intra-articular delivery of AdProTDeltaNLS significantly ameliorated the clinical course of CIA in rats. This study is the first to suggest that ProT lacking the NLS may have therapeutic potential for the management of rheumatoid arthritis.

Serum chemokine profile in patients with bullous pemphigoid

BACKGROUND

Bullous pemphigoid (BP) is an autoimmune inflammatory disease causing blister formation at the dermoepidermal junction. Cutaneous infiltration of activated CD4+ T cells and eosinophils is an early event in blister formation during the disease process, suggesting that the trafficking of circulating leucocytes through the sites of inflammation is crucial in the pathogenesis of the disease. While the accumulated evidence suggests that some cytokines are involved in the pathogenesis, there have been few reports about serum chemokine profiles in patients with BP.

OBJECTIVES

To determine serum profiles of various chemokines and their clinical association in patients with BP.

METHODS

Concentrations of 10 chemokines - interferon (IFN)-gamma-inducible protein-10 (IP-10), monokine induced by IFN-gamma (MIG), macrophage inflammatory protein (MIP)-1alpha, MIP-1beta, RANTES, eotaxin, monocyte chemoattractant protein (MCP)-1, MCP-2, MCP-3 and growth-regulated oncogene-alpha- were measured in serum samples from 38 patients with BP, 16 with pemphigus vulgaris (PV) and 17 normal controls using a sandwich immunoassay-based multiplex protein array system.

RESULTS

While there was no significant increase in any serum chemokine levels in patients with PV, serum levels of IP-10 and MCP-1 were significantly increased in patients with BP compared with healthy controls. Furthermore, serum levels of IP-10, MIG, MCP-1 and eotaxin in patients with BP increased significantly with disease severity as determined by the area affected.

CONCLUSIONS

These observations suggest that an elaborately orchestrated network of chemokines, especially MCP-1 and IP-10, contributes to the pathomechanism of BP.

T-cell contact-dependent regulation of CC and CXC chemokine production in monocytes through differential involvement of NFkappaB: implications for rheumatoid arthritis

We and others have reported that rheumatoid arthritis (RA) synovial T cells can activate human monocytes/macrophages in a contact-dependent manner to induce the expression of inflammatory cytokines, including tumour necrosis factor alpha (TNFα). In the present study we demonstrate that RA synovial T cells without further activation can also induce monocyte CC and CXC chemokine production in a contact-dependent manner. The transcription factor NFκB is differentially involved in this process as CXC chemokines but not CC chemokines are inhibited after overexpression of IκBα, the natural inhibitor of NFκB. This effector function of RA synovial T cells is also shared by T cells activated with a cytokine cocktail containing IL-2, IL-6 and TNFα, but not T cells activated by anti-CD3 cross-linking that mimics TCR engagement. This study demonstrates for the first time that RA synovial T cells as well as cytokine-activated T cells are able to induce monocyte chemokine production in a contact-dependent manner and through NFκB-dependent and NFκB-independent mechanisms, in a process influenced by the phosphatidyl-inositol-3-kinase pathway. Moreover, this study provides further evidence that cytokine-activated T cells share aspects of their effector function with RA synovial T cells and that their targeting in the clinic has therapeutic potential.

Macrophage inflammatory protein-1α: A link between innate immunity and familial mediterranean fever?

The aim of this study is to investigate the relationship between chemokines and the inflammation in Familial Mediterranean Fever (FMF). Forty-nine patients with FMF (41 in remission and 8 in acute attack period) and 20 healthy controls were included in the study. Serum levels of macrophage inflammatory protein-1alpha (MIP-1alpha) were assessed in the patients and the controls, along with other parameters of disease activity, i.e., fibrinogen, C-reactive protein and erythrocyte sedimentation rate. Serum MIP-1alpha levels of the patients with FMF in acute attack period were significantly higher than the patients in remission and healthy controls (p=0.02 and p=0.038, respectively). MIP-1alpha levels were weakly correlated with CRP (r=0.32, p=0.032) levels. MIP-1alpha may have a role in the pathogenesis of FMF attacks. MIP-1alpha and other chemokines may constitute a link between the innate immune system and FMF.

RANTES and chemotactic activity in synovial fluids from patients with rheumatoid arthritis and osteoarthritis

A massive accumulation of inflammatory cells in synovial tissues is a major pathological feature of rheumatoid arthritis (RA). Neutrophiles dominate synovial fluid while rheumatoid synovium is infiltrated with mononuclear cells. Mechanisms regulating influx of particular subpopulations of leukocytes into articular cavity and synovium compartment are not completely defined. An increasing amount of data supports a crucial role of a C-C chemokine RANTES in the RA pathogenesis. Our objective is to evaluate chemotactic activity for neutrophils (NCA), lymphocytes (LCA), and monocytes (MoCA) in SFs obtained from patients with RA and osteoarthritis (OA). We also aimed to characterise the relation between chemotactic activity, RANTES, and percentage distribution of leukocytes in SF. SFs from 11 patients with RA and 6 with OA were included in the study. Modified microchamber Boyden method was employed to assess chemotactic activity. Cytological and biochemical analysis of SF was performed. RANTES was measured with ELISA. Rheumatoid SFs were rich in cells with predominance of neutrophiles while osteoarthritic fluids were lymphocytic. RA SFs were also characterised by increased lactoferrin level. Both NCA and LCA were higher in SF from patients with RA (62 ± 12 and 24 ± 6 cells/HPF, resp) as compared to patients with OA (23 ± 6; P < .05 and 6 ± 2 cells/HPF; P < 0.05). The chemoattractive effect of RA SF was more pronounced on neutrophiles than on lymphocytes. RA SF expressed high RANTES levels (145 ± 36 pg/mL), while OA SF was characterised by only trace amount of this chemokine (2 ± 1 pg/mL). We found positive correlation of RANTES with chemotactic activity for mononuclear cells (LCA+MoCA; R = 0.61; P < .05). Surprisingly, RANTES correlated also positively with neutrophiles number (R = 0.77; P < 0.001). Rheumatoid SF possesses strong chemotactic potency for leukocytes. RANTES is overexpressed in RA SF and is a potential mediator influencing intensity and composition of cellular infiltration in joints affected with inflammatory arthritis.

Triptolide inhibits CC chemokines expressed in rat adjuvant-induced arthritis

Triptolide, a diterpenoid triepoxide from Tripterygium wilfordii Hook F (TWHF), has been proven to have potent immunosuppressive and anti-inflammatory activities. It has been clinically used to treat patients with rheumatoid arthritis (RA), in which chemokines play an important role in immune and inflammatory responses. To investigate the effect of triptolide on MCP-1, MIP-1alpha and RANTES, we used complete Freund's adjuvant to induce adjuvant-induced arthritis (AA) in rats. AA in rat is a useful experimental model of human RA. Our data show that the thickness of arthritic ankle decreases with administration of triptolide. Both mRNA and protein levels of MCP-1, MIP-1alpha and RANTES in synovial tissue of rats with AA are significantly higher than those in normal rats. mRNA levels of MIP-1alpha and RANTES increase in peripheral blood mononuclear cells of rats with AA in comparison with those in normal rats, whereas no MCP-1 mRNA can be detected. Triptolide can significantly inhibit rat AA induced over-expression of MCP-1, MIP-1alpha and RANTES at both mRNA and protein levels in a dose-dependent manner. These results may contribute to the therapeutic effects of triptolide in rheumatoid arthritis.

Function of interleukin-20 as a proinflammatory molecule in rheumatoid and experimental arthritis

OBJECTIVE

The pathogenesis of rheumatoid arthritis (RA) reflects an ongoing imbalance between proinflammatory and antiinflammatory cytokines. Interleukin-20 (IL-20) has proinflammatory properties for keratinocytes. In this study, we sought to determine whether IL-20 is involved in RA.

METHODS

We analyzed IL-20 levels in synovial fluid from RA patients. IL-20 and its receptors were detected in RA synovial fibroblasts (RASFs), using immunohistochemical staining. The effect of IL-20 on endothelial cells, neutrophils, and RASFs was investigated using MTT and migration assays. The expression of IL-20 and its receptors in healthy rats and in rats with collagen-induced arthritis (CIA) was also analyzed. Soluble IL-20 receptor type I (sIL-20RI) or sIL-20RII was administered to rats with CIA by intramuscular electroporation, and the severity of arthritis was monitored.

RESULTS

RA patients expressed significantly higher levels of synovial fluid IL-20 than did the rheumatic disease controls. IL-20 and its receptors were expressed in the synovial membranes and RASFs. IL-20 induced RASFs to secrete monocyte chemoattractant protein 1, IL-6, and IL-8, and it promoted neutrophil chemotaxis, RASF migration, and endothelial cell proliferation. Both IL-20 and IL-20RI were up-regulated in the rat CIA model. In vivo, electroporated sIL-20RI plasmid DNA decreased the severity of arthritis in the rats with CIA.

CONCLUSION

IL-20 was up-regulated in the synovial fluid of RA patients and acted as a chemokine that attracted the migration of neutrophils and RASFs in vitro. The rat CIA model demonstrated that IL-20 was involved in the pathogenesis of arthritis, because sIL-20RI significantly reduced arthritis in rats with CIA. Thus, IL-20 may modulate the incidence and severity of arthritis and play important roles at local sites of inflammation.

Allelic frequency of the MCP-1 promoter −2518 polymorphism in the Turkish population and in Turkish patients with juvenile rheumatoid arthritis

Although genetic and environmental factors contribute to the pathogenesis of juvenile rheumathoid arthritis (JRA), the etiology and pathogenesis remain controversial. The objective of this study was to investigate genotypic and allelic frequencies of monocyte chemoattractant protein-1 (MCP-1) gene -2518 (G/A) polymorphism in the healthy Turkish population and patients with JRA. Genomic DNA was collected from 66 JRA patients and 150 healthy individuals. To evaluate the association of the -2518 (G/A) MCP-1 gene polymorphism with the outcome of JRA, we analyzed the types of JRA and the score on the childhood health assessment questionnaire (C-HAQ score). In the healthy Turkish population, the frequencies of A and G alleles were 71 and 29%, respectively. No significant difference was observed between the JRA patients and healthy subjects in the distribution allelic and genotypic frequencies of the -2518 (G/A) MCP-1 gene polymorphism (p>0.05). However, the AG genotype was found to be higher and the AA genotype was found to be lower in the patients with systemic type JRA compared to those with the other types of JRA (p=0.019). When the JRA patients were evaluated according to the C-HAQ score, we found that the -2518 (G/A) MCP-1 gene polymorphism did not relate the prognosis (p>0.05). AG genotype was found to be higher in the systemic type of JRA. The results indicate that MCP-1 gene polymorphism might slightly associate with patients with systemic JRA. Further studies are needed to elucidate the role of this polymorphism in the pathogenesis of JRA in various populations because this polymorphism has a functional significance and an ethnic difference.

Essential role of neutrophils in anti-type II collagen antibody and lipopolysaccharide-induced arthritis

In mice arthritis model induced by anti-type II collagen (CII) antibodies and lipopolysaccharide (LPS), most of cells that infiltrated into the joint space were neutrophils. To investigate the role of neutrophils in the pathogenesis of arthritis, we depleted the neutrophils in vivo by injection of the antibody against Gr-1 expressed mainly on neutrophils. The neutrophil depletion completely inhibited the arthritis development. Furthermore, neutrophil depletion in mice that had already developed arthritis ameliorated the disease. These results showed that neutrophils are indispensable not only for the development, but also for the maintenance of arthritis. Next, we tried to develop arthritis in C5-deficient mice to investigate the involvement of C5a, one of chemotactic factors for neutrophils. C5-deficient mice showed significant reduction in arthritis development in comparison with wild type mice. Injection of pertussis toxin (Ptx) into the mice, which inhibits the signals from the inhibitory G-protein coupled-receptors including the C5a receptor, suppressed the development of arthritis. Furthermore, Ptx also ameliorated the arthritis when injected into mice that had already developed the disease. These results suggest the important role of chemotactic factors involving C5a and inhibitory G-protein (Gi)-coupled receptors not only in the development, but also in the maintenance of arthritis.