IRF5:RelA interaction targets inflammatory genes in macrophages.

Interferon Regulatory Factor 5 (IRF5) plays a major role in setting up an inflammatory macrophage phenotype, but the molecular basis of its transcriptional activity is not fully understood. In this study, we conduct a comprehensive genome-wide analysis of IRF5 recruitment in macrophages stimulated with bacterial lipopolysaccharide and discover that IRF5 binds to regulatory elements of highly transcribed genes. Analysis of protein:DNA microarrays demonstrates that IRF5 recognizes the canonical IRF-binding (interferon-stimulated response element [ISRE]) motif in vitro.

Intrinsic danger: activation of Toll-like receptors in rheumatoid arthritis.

RA is a debilitating disorder that manifests as chronic localized synovial and systemic inflammation leading to progressive joint destruction. Recent advances in the molecular basis of RA highlight the role of both the innate and adaptive immune system in disease pathogenesis. Specifically, data obtained from in vivo animal models and ex vivo human tissue explants models has confirmed the central role of Toll-like receptors (TLRs) in RA.

Beyond the enhanceosome: cluster of novel κB sites downstream of the human IFN-β gene is essential for lipopolysaccharide-induced gene activation.

The expression of interferon-β (IFN-β) in virus-infected HeLa cells established a paradigm of multifactorial gene regulation, in which cooperative assembly of transcription factors (TFs) at the composite DNA element (enhanceosome), is central for amplification of weak activating signals provided by individual TFs. However, whether the same TFs and the same DNA element are essential for IFN-β induction in response to bacterial stimuli are less well understood. Here we report that rapid and transient transcription of IFN-β in response to TLR4 stimulation with bacterial lipopolysaccharide (LPS) follows nuclear factor-κB (NF-κB) RelA activation and recruitment to the IFN-β genomic locus at multiple spatially separated regulatory regions.

Transcriptional regulation of the endogenous danger signal tenascin-C: a novel autocrine loop in inflammation.

Inappropriate expression of proinflammatory mediators underpins the pathogenesis of autoimmune disease and tumor metastasis. The extracellular matrix glycoprotein tenascin-C is an endogenous activator of innate immunity that promotes the synthesis of inflammatory cytokines via activation of TLR4. Little tenascin-C is observed in most healthy adult tissues, but expression is specifically upregulated at sites of inflammation.

Dual effect of the novel peptide antagonist K-14585 on proteinase-activated receptor-2-mediated signalling.

Background And Purpose: Here we have examined the effects of the novel peptide antagonist N-[1-(2,6-dichlorophenyl)methyl]-3-(1-pyrrolidinylmethyl)-1H-indol-5-yl]aminocarbonyl]-glycinyl-L-lysinyl-L-phenylalanyl-N-benzhydrylamide (K-14585) on proteinase-activated receptor (PAR)(2)-mediated intracellular signalling events.

Experimental Approach: Using NCTC2544 cells expressing PAR(2), we assessed the effects of K-14585 on PAR(2)-mediated [(3)H] inositol phosphate accumulation, MAP kinase activation, p65 NFkappaB phosphorylation and DNA binding and IL-8 production.

Key Results: Pretreatment with K-14585 (5 microM) inhibited [(3)H] inositol phosphate levels stimulated by PAR(2)-activating peptide Ser-Leu-Ile-Gly-Lys-Val (SLIGKV-OH) in PAR(2)-expressing NCTC2544 cells.

The role of transposable elements in the regulation of IFN-lambda1 gene expression.

IFNs lambda1, lambda2, and lambda3, or type III IFNs, are recently identified cytokines distantly related to type I IFNs. Despite an early evolutionary divergence, the 2 types of IFNs display similar antiviral activities, and both are produced primarily in dendritic cells. Although virus induction of the type I IFN-beta gene had served as a paradigm of gene regulation, relatively little is known about the regulation of IFN-lambda gene expression.

Detecting and modulating the NF-kB activity in human immune cells: generation of human cell lines with altered levels of NF-kappaB.

NF-kappaB plays a pivotal role in immunity and inflammation and is considered to be a promising candidate for drug development. However, global suppression of NF-kappaB may have undesirable side-effects. Our data and the results of others suggest that each of the five NF-kappaB subunits may have a specific function in controlling the expression of inflammatory mediators in immune cells.