Osteoarticular Expression of Musashi-1 in an Experimental Model of Arthritis.

Background. Collagen-induced arthritis (CIA), a murine experimental disease model induced by immunization with type II collagen (CII), is used to evaluate novel therapeutic strategies for rheumatoid arthritis. Adult stem cell marker Musashi-1 (Msi1) plays an important role in regulating the maintenance and differentiation of stem/precursor cells. The objectives of this investigation were to perform a morphological study of the experimental CIA model, evaluate the effect of TNFα-blocker (etanercept) treatment, and determine the immunohistochemical expression of Msi1 protein. Methods. CIA was induced in 50 male DBA1/J mice for analyses of tissue and serum cytokine; clinical and morphological lesions in limbs; and immunohistochemical expression of Msi1. Results. Clinically, TNFα-blocker treatment attenuated CIA on day 32 after immunization (P < 0.001). Msi1 protein expression was significantly higher in joints damaged by CIA than in those with no lesions (P < 0.0001) and was related to the severity of the lesions (Spearman's rho = 0.775, P = 0.0001). Conclusions. Treatment with etanercept attenuates osteoarticular lesions in the murine CIA model. Osteoarticular expression of Msi1 protein is increased in joints with CIA-induced lesion and absent in nonlesioned joints, suggesting that this protein is expressed when the lesion is produced in order to favor tissue repair.

T cells dampen innate immune responses through inhibition of NLRP1 and NLRP3 inflammasomes.

Inflammation is a protective attempt by the host to remove injurious stimuli and initiate the tissue healing process. The inflammatory response must be actively terminated, however, because failure to do so can result in 'bystander' damage to tissues and diseases such as arthritis or type-2 diabetes. Yet the mechanisms controlling excessive inflammatory responses are still poorly understood. Here we show that mouse effector and memory CD4(+) T cells abolish macrophage inflammasome-mediated caspase-1 activation and subsequent interleukin 1beta release in a cognate manner. Inflammasome inhibition is observed for all tested NLRP1 (commonly called NALP1) and NLRP3 (NALP3 or cryopyrin) activators, whereas NLRC4 (IPAF) inflammasome function and release of other inflammatory mediators such as CXCL2, interleukin 6 and tumour necrosis factor are not affected. Suppression of the NLRP3 inflammasome requires cell-to-cell contact and can be mimicked by macrophage stimulation with selected ligands of the tumour necrosis factor family, such as CD40L (also known as CD40LG). In a NLRP3-dependent peritonitis model, effector CD4(+) T cells are responsible for decreasing neutrophil recruitment in an antigen-dependent manner. Our findings reveal an unexpected mechanism of inflammasome inhibition, whereby effector and memory T cells suppress potentially damaging inflammation, yet leave the primary inflammatory response, crucial for the onset of immunity, intact.

Response to Infliximab in Crohn's Disease: Genetic Analysis Supporting Expression Profile.

Substantial proportion of Crohn's disease (CD) patients shows no response or a limited response to treatment with infliximab (IFX) and to identify biomarkers of response would be of great clinical and economic benefit. The expression profile of five genes (S100A8-S100A9, G0S2, TNFAIP6, and IL11) reportedly predicted response to IFX and we aimed at investigating their etiologic role through genetic association analysis. Patients with active CD (350) who received at least three induction doses of IFX were included and classified according to IFX response. A tagging strategy was used to select genetic polymorphisms that cover the variability present in the chromosomal regions encoding the identified genes with altered expression. Following genotyping, differences between responders and nonresponders to IFX were observed in haplotypes of the studied regions: S100A8-S100A9 (rs11205276* G/rs3014866* C/rs724781* C/rs3006488* A; P = 0.05); G0S2 (rs4844486* A/rs1473683* T; P = 0.15); TNFAIP6 (rs11677200* C/rs2342910* A/rs3755480* G/rs10432475* A; P = 0.10); and IL11 (rs1126760* C/rs1042506* G; P = 0.07). These differences were amplified in patients with colonic and ileocolonic location for all but the TNFAIP6 haplotype, which evidenced significant difference in ileal CD patients. Our results support the role of the reported expression signature as predictive of anti-TNF outcome in CD patients and suggest an etiological role of those top-five genes in the IFX response pathway.

Biological treatments in Behçet's disease: beyond anti-TNF therapy.

Behçet's disease (BD) is universally recognized as a multisystemic inflammatory disease of unknown etiology with chronic course and unpredictable exacerbations: its clinical spectrum varies from pure vasculitic manifestations with thrombotic complications to protean inflammatory involvement of multiple organs and tissues. Treatment has been revolutionized by the progressed knowledge in the pathogenetic mechanisms of BD, involving dysfunction and oversecretion of multiple proinflammatory molecules, chiefly tumor necrosis factor- (TNF-) α, interleukin- (IL-) 1β, and IL-6. However, although biological treatment with anti-TNF-α agents has been largely demonstrated to be effective in BD, not all patients are definite responders, and this beneficial response might drop off over time. Therefore, additional therapies for a subset of refractory patients with BD are inevitably needed. Different agents targeting various cytokines and their receptors or cell surface molecules have been studied: the IL-1 receptor has been targeted by anakinra, the IL-1 by canakinumab and gevokizumab, the IL-6 receptor by tocilizumab, the IL12/23 receptor by ustekinumab, and the B-lymphocyte antigen CD-20 by rituximab. The aim of this review is to summarize all current experiences and the most recent evidence regarding these novel approaches with biological drugs other than TNF-α blockers in BD, providing a valuable addition to the actually available therapeutic armamentarium.

TRAIL receptor-mediated JNK activation and Bim phosphorylation critically regulate Fas-mediated liver damage and lethality.

TNF-related apoptosis-inducing ligand (TRAIL) is a member of the TNF family with potent apoptosis-inducing properties in tumor cells. In particular, TRAIL strongly synergizes with conventional chemotherapeutic drugs to induce tumor cell death. Thus, TRAIL has been proposed as a promising future cancer therapy. Little, however, is known regarding what the role of TRAIL is in normal untransformed cells and whether therapeutic administration of TRAIL, alone or in combination with other apoptotic triggers, may cause tissue damage. In this study, we investigated the role of TRAIL in Fas-induced (CD95/Apo-1-induced) hepatocyte apoptosis and liver damage. While TRAIL alone failed to induce apoptosis in isolated murine hepatocytes, it strongly amplified Fas-induced cell death. Importantly, endogenous TRAIL was found to critically regulate anti-Fas antibody-induced hepatocyte apoptosis, liver damage, and associated lethality in vivo. TRAIL enhanced anti-Fas-induced hepatocyte apoptosis through the activation of JNK and its downstream substrate, the proapoptotic Bcl-2 homolog Bim. Consistently, TRAIL- and Bim-deficient mice and wild-type mice treated with a JNK inhibitor were protected against anti-Fas-induced liver damage. We conclude that TRAIL and Bim are important response modifiers of hepatocyte apoptosis and identify liver damage and lethality as a possible risk of TRAIL-based tumor therapy.

Assessing cardiovascular risk in hepatitis C: An unmet need.

Chronic hepatitis C virus (HCV) is associated with significant morbidity and mortality, as a result of the progression towards cirrhosis and hepatocellular carcinoma. Additionally, HCV seems to be an independent risk factor for cardiovascular diseases (CVD) due to its association with insulin resistance, diabetes and steatosis. HCV infection represents an initial step in the chronic inflammatory cascade, showing a direct role in altering glucose metabolism. After achieving sustained virological response, the incidence of insulin resistance and diabetes dramatically decrease. HCV core protein plays an essential role in promoting insulin resistance and oxidative stress. On the other hand, atherosclerosis is a common disease in which the artery wall thickens due to accumulation of fatty deposits. The main step in the formation of atherosclerotic plaques is the oxidation of low density lipoprotein particles, together with the increased production of proinflammatory markers [tumor necrosis factor-α, interleukin (IL)-6, IL-18 or C-reactive protein]. The advent of new direct acting antiviral therapy has dramatically increased the sustained virological response rates of hepatitis C infection. In this scenario, the cardiovascular risk has emerged and represents a major concern after the eradication of the virus. Consequently, the number of studies evaluating this association is growing. Data derived from these studies have demonstrated the strong link between HCV infection and the atherogenic process, showing a higher risk of coronary heart disease, carotid atherosclerosis, peripheral artery disease and, ultimately, CVD-related mortality.

Rheumatoid arthritis response to treatment across IgG1 allotype - anti-TNF incompatibility: a case-only study.

INTRODUCTION We have hypothesized that incompatibility between the G1m genotype of the patient and the G1m1 and G1m17 allotypes carried by infliximab (INX) and adalimumab (ADM) could decrease the efficacy of these anti-tumor necrosis factor (anti-TNF) antibodies in the treatment of rheumatoid arthritis (RA). METHODS The G1m genotypes were analyzed in three collections of patients with RA totaling 1037 subjects. The first, used for discovery, comprised 215 Spanish patients. The second and third were successively used for replication. They included 429 British and Greek patients and 393 Spanish and British patients, respectively. Two outcomes were considered: change in the Disease Activity Score in 28 joint (ΔDAS28) and the European League Against Rheumatism (EULAR) response criteria. RESULTS An association between less response to INX and incompatibility of the G1m1,17 allotype was found in the discovery collection at 6 months of treatment (P = 0.03). This association was confirmed in the replications (P = 0.02 and 0.08, respectively) leading to a global association (P = 0.001) that involved a mean difference in ΔDAS28 of 0.4 units between compatible and incompatible patients (2.3 ± 1.5 in compatible patients vs. 1.9 ± 1.5 in incompatible patients) and an increase in responders and decrease in non-responders according to the EULAR criteria (P = 0.03). A similar association was suggested for patients treated with ADM in the discovery collection, but it was not supported by replication. CONCLUSIONS Our results suggest that G1m1,17 allotypes are associated with response to INX and could aid improved therapeutic targeting in RA.

Granulomatoses cutanées disséminées : orientation diagnostique et prise en charge [Disseminated cutaneous granulomatosis]

Les granulomatoses cutanées disséminées (GCD) sont des dermatoses cliniquement et histologiquement hétérogènes, caractérisées à la biopsie cutanée par un infiltrat granulomateux. Même si la biopsie est utile pour poser le diagnostic de GCD, elle n'apporte que rarement des éléments étiologiques. La principale cause est la sarcoïdose cutanée, mais de nombreuses étiologies peuvent être retrouvées, car ces dermatoses correspondent vraisemblablement à un processus réactionnel cutané granulomateux à différents stimuli: infectieux, inflammatoires, néoplasiques, métaboliques ou chimiques. Par cet article, nous aborderons la conduite à tenir une fois le diagnostic clinique et histologique de GCD posé, par une approche centrée sur l'étiologie et proposerons des recommandations thérapeutiques, sur la base de cas et de séries rapportées dans la littérature.

Cytotoxic T cells deficient in both functional fas ligand and perforin show residual cytolytic activity yet lose their capacity to induce lethal acute graft-versus-host disease.

Graft-versus-host disease (GVHD) is the main complication after allogeneic bone marrow transplantation. Although the tissue damage and subsequent patient mortality are clearly dependent on T lymphocytes present in the grafted inoculum, the lethal effector molecules are unknown. Here, we show that acute lethal GVHD, induced by the transfer of splenocytes from C57BL/6 mice into sensitive BALB/c recipients, is dependent on both perforin and Fas ligand (FasL)-mediated lytic pathways. When spleen cells from mutant mice lacking both effector molecules were transferred to sublethally irradiated allogeneic recipients, mice survived. Delayed mortality was observed with grafted cells deficient in only one lytic mediator. In contrast, protection from lethal acute GVHD in resistant mice was exclusively perforin dependent. Perforin-FasL-deficient T cells failed to lyse most target cells in vitro. However, they still efficiently killed tumor necrosis factor alpha-sensitive fibroblasts, demonstrating that cytotoxic T cells possess a third lytic pathway.

Markers of atherosclerosis and of inflammation for prediction of coronary heart disease in older adults

BACKGROUND: Several markers of atherosclerosis and of inflammation have been shown to predict coronary heart disease (CHD) individually. However, the utility of markers of atherosclerosis and of inflammation on prediction of CHD over traditional risk factors has not been well established, especially in the elderly. METHODS: We studied 2202 men and women, aged 70-79, without baseline cardiovascular disease over 6-year follow-up to assess the risk of incident CHD associated with baseline noninvasive measures of atherosclerosis (ankle-arm index [AAI], aortic pulse wave velocity [aPWV]) and inflammatory markers (interleukin-6 [IL-6], C-reactive protein [CRP], tumor necrosis factor-a [TNF-a]). CHD events were studied as either nonfatal myocardial infarction or coronary death ("hard" events), and "hard" events plus hospitalization for angina, or the need for coronary-revascularization procedures (total CHD events). RESULTS: During the 6-year follow-up, 283 participants had CHD events (including 136 "hard" events). IL-6, TNF-a and AAI independently predicted CHD events above Framingham Risk Score (FRS) with hazard ratios [HR] for the highest as compared with the lowest quartile for IL-6 of 1.95 (95%CI: 1.38-2.75, p for trend<0.001), TNF-a of 1.45 (95%CI: 1.04-2.02, p for trend 0.03), of 1.66 (95%CI: 1.19-2.31) for AAI £0.9, as compared to AAI 1.01-1.30. CRP and aPWV were not independently associated with CHD events. Results were similar for "hard" CHD events. Addition of IL-6 and AAI to traditional cardiovascular risk factors yielded the greatest improvement in the prediction of CHD; C-index for "hard"/total CHD events increased from 0.62/0.62 for traditional risk factors to 0.64/0.64 for IL-6 addition, 0.65/0.63 for AAI, and 0.66/0.64 for IL-6 combined with AAI. Being in the highest quartile of IL-6 combined with an AAI £ 0.90 or >1.40 yielded an HR of 2.51 (1.50-4.19) and 4.55 (1.65-12.50) above FRS, respectively. With use of CHD risk categories, risk prediction at 5 years was more accurate in models that included IL-6, AAI or both, with 8.0, 8.3 and 12.1% correctly reclassified respectively. CONCLUSIONS: Among older adults, markers of atherosclerosis and of inflammation, particularly IL-6 and AAI, are independently associated with CHD. However, these markers only modestly improve cardiovascular risk prediction beyond traditional risk factors. Acknowledgments: This study was supported by Contracts NO1-AG-6-2101, NO1-AG-6- 2103, and NO1-AG-6-2106 of the National Institute on Aging. This research was supported in part by the Intramural Research Program of the NIH, National Institute on Aging.

Suppression of tumor angiogenesis through the inhibition of integrin function and signaling in endothelial cells: which side to target?

Tumor angiogenesis is an essential step in tumor progression and metastasis formation. Suppression of tumor angiogenesis results in the inhibition of tumor growth. Recent evidence indicates that vascular integrins, in particular alpha V beta 3, are important regulators of angiogenesis, including tumor angiogenesis. Integrin alpha V beta 3 antagonists, such as blocking antibodies or peptides, suppress tumor angiogenesis and tumor progression in many preclinical tumor models. The potential therapeutic efficacy of extracellular integrin antagonists in human cancer is currently being tested in clinical trials. Selective disruption of the tumor vasculature by high doses of tumor necrosis factor (TNF) and interferon gamma (IFN-gamma), and the antiangiogenic activity of nonsteroidal anti-inflammatory drugs are associated with the suppression of integrin alpha V beta 3 function and signaling in endothelial cells. Furthermore, expression of isolated integrin cytoplasmic domains disrupts integrin-dependent adhesion, resulting in endothelial cell detachment and apoptosis. These results confirm the critical role of vascular integrins in promoting endothelial cell survival and angiogenesis and suggest that intracellular targeting of integrin function and signaling may be an alternative strategy to extracellular integrin antagonists for the therapeutic inhibition of tumor angiogenesis.

High prevalence of anti-apolipoprotein/A-1 autoantibodies in maintenance hemodialysis and association with dialysis vintage.

Autoantibodies to apolipoprotein/A-1 (anti-ApoA-1 IgG) have pro-atherogenic properties in patients at high cardiovascular risk, but its prevalence in patients with end-stage kidney disease is unknown. The aims of this single-center, cross-sectional study were to assess the prevalence of anti-ApoA-1 antibodies in patients on maintenance hemodialysis (MHD), and to examine its correlation with inflammatory biomarkers related to atherosclerotic plaque vulnerability and dialysis vintage. To this purpose, anti-ApoA-1 IgG levels and the concentrations of interleukin-6 (IL-6), interleukin-8 (IL-8), monocyte chemoattractant protein-1 (MCP-1), metalloproteinase-9 (MMP-9), tumor necrosis factor-α, and C-reactive protein (CRP) were assessed in the sera of 66 MHD patients (mean age: 68 ± 14 years, 36% women, 32% diabetics). Anti-ApoA-1 IgG positivity (defined as a blood value ≥ 97.5(th) percentile of the normal distribution as assessed in healthy blood donors) was 20%. Circulating levels of anti-ApoA-1 IgG correlated positively with dialysis vintage, but not with cardiovascular risk factors or previous cardiovascular events; no significant correlations were found between the anti-ApoA1 IgG levels and circulating levels of IL-6, IL-8, MCP-1, MMP-9, CRP, or low-density lipoprotein-cholesterol. In multivariable linear regression, adjusted for age and sex, only dialysis vintage remained positively and independently associated with anti-ApoA-1 titers (β = 0.05, 95% CI: 0.006; 0.28, P = 0.049). In conclusion, the prevalence of anti-ApoA-1 IgG is raised in the MHD-population, and positively associated with dialysis vintage, a major determinant of cardiovascular outcome. Whether antiApoA-1 antibodies play a role in the pathophysiology of accelerated atherosclerosis in the MHD-population merits further study.

The molecular architecture of the TNF superfamily.

Ligands of the TNF (tumour necrosis factor) superfamily have pivotal roles in the organization and function of the immune system, and are implicated in the aetiology of several acquired and genetic diseases. TNF ligands share a common structural motif, the TNF homology domain (THD), which binds to cysteine-rich domains (CRDs) of TNF receptors. CRDs are composed of structural modules, whose variation in number and type confers heterogeneity upon the family. Protein folds reminiscent of the THD and CRD are also found in other protein families, raising the possibility that the mode of interaction between TNF and TNF receptors might be conserved in other contexts.

Inflammatory responses in aggregating rat brain cell cultures subjected to different demyelinating conditions.

To study inflammatory reactions occurring in relation to demyelination, aggregating rat brain cell cultures were subjected to three different demyelinating insults, i.e., (i) lysophosphatidylcholine (LPC), (ii) interferon-gamma combined with lipopolysaccharide (IFN-gamma+LPS), and (iii) anti-MOG antibodies plus complement (alpha-MOG+C). Demyelination was assessed by measuring the expression of myelin basic protein (MBP) and myelin oligodendrocyte glycoprotein (MOG), and the activity of 2',3'-cyclic nucleotide 3'-phosphohydrolase (CNP). The accompanying inflammatory reactions were examined by the quantification of microglia-specific staining, by immunostaining for glial fibrillary acidic protein (GFAP), and by measuring the mRNA expression of a panel of inflammation-related genes. It was found that all three demyelinating insults decreased the expression of MBP and MOG, and induced microglial reactivity. LPC and alpha-MOG+C, but not IFN-gamma+LPS, decreased CNP activity; they also caused the appearance of macrophagic microglia, and increased GFAP staining indicating astrogliosis. LPC affected also the integrity of neurons and astrocytes. LPC and IFN-gamma+LPS upregulated the expression of the inflammation-related genes IL-6, TNF-alpha, Ccl5, Cxcl1, and iNOS, although to different degrees. Other inflammatory markers were upregulated by only one of the three insults, e.g., Cxcl2 by LPC; IL-1beta and IL-15 by IFN-gamma+LPS; and IFN-gamma by alpha-MOG+C. These findings indicate that each of the three demyelinating insults caused distinct patterns of demyelination and inflammatory reactivity, and that of the demyelinating agents tested only LPC exhibited general toxicity.

Functional analysis of Ectodysplasin-A mutations causing selective tooth agenesis.

Mutations of the Ectodysplasin-A (EDA) gene are generally associated with the syndrome hypohidrotic ectodermal dysplasia (MIM 305100), but they can also manifest as selective, non-syndromic tooth agenesis (MIM300606). We have performed an in vitro functional analysis of six selective tooth agenesis-causing EDA mutations (one novel and five known) that are located in the C-terminal tumor necrosis factor homology domain of the protein. Our study reveals that expression, receptor binding or signaling capability of the mutant EDA1 proteins is only impaired in contrast to syndrome-causing mutations, which we have previously shown to abolish EDA1 expression, receptor binding or signaling. Our results support a model in which the development of the human dentition, especially of anterior teeth, requires the highest level of EDA-receptor signaling, whereas other ectodermal appendages, including posterior teeth, have less stringent requirements and form normally in response to EDA mutations with reduced activity.