Inducible interleukin-1 gene expression in human vascular smooth muscle cells.

Interleukin-1 (IL-1) mediates many components of generalized host response to injury and may also contribute to local vascular pathology during immune or inflammatory responses. Because altered function of smooth muscle cells (SMC) accompanies certain vascular diseases, we tested whether SMC themselves might produce this hormone. Unstimulated SMC contain little or no IL-1 mRNA. However, exposure to bacterial endotoxin caused accumulation of IL-1 mRNA in SMC cultured from human vessels. Endotoxin maximally increased IL-1 beta mRNA in SMC after 4-6 h. The lowest effective concentration of endotoxin was 10 pg/ml. 10 ng/ml produced maximal increases in IL-1 beta mRNA. Interleukin-1 alpha mRNA was detected when SMC were incubated with endotoxin under "superinduction" conditions with cycloheximide. Endotoxin-stimulated SMC also released biologically functional IL-1, measured as thymocyte costimulation activity inhibitable by anti-IL-1 antibody. Thus, human SMC can express IL-1 beta and IL-1 alpha genes, or very similar ones, and secrete biologically active product in response to a pathological stimulus. Endogenous local production of this inflammatory mediator by the blood vessel wall's major cell type could play an important early role in the pathogenesis of vasculitis and arteriosclerosis

cDNA Cloning of Biologically Active Chicken Interleukin-18

By searching a chicken EST database, we identified a cDNA clone that appeared to contain the entire open reading frame (ORF) of chicken interleukin-18 (ChIL-18). The encoded protein consists of 198 amino acids and exhibits approximately 30% sequence identity to IL-18 of humans and various others mammals. Sequence comparisons reveals a putative caspase-1 cleavage site at aspartic acid 29 of the primary translation product, indicating that mature ChIL-18 might consist of 169 amino acids. Bacterially expressed ChIL-18 in which the N-terminal 29 amino acids of the putative precursor molecule were replaced by a histidine tag induced the synthesis of interferon-γ (IFN-γ) in cultured primary chicken spleen cells, indicating that the recombinant protein is biologically active

Handbook for Aboriginal Alcohol and Drug Work

The Handbook for Aboriginal Alcohol and Drug Work is a practical tool written for Aboriginal drug and alcohol workers, mental health workers and others working in this field. It offers a detailed look at alcohol and drug work from clinical, through to prevention, early intervention and harm reduction. This handbook is also likely to help people working to improve policy and those advocating for change. The idea for it came from workers all over Australia. They told us that they needed an easy to use handbook that can help them respond to the range of alcohol and drug issues they face every day. They also told us that such a book needs to take into account the complex challenges facing workers when helping clients, their families and, sometimes, whole communities

Mycobacterium tuberculosis Induces Interleukin-32 Production through a Caspase- 1/IL-18/Interferon-γ-Dependent Mechanism

BACKGROUND: Interleukin (IL)–32 is a newly described proinflammatory cytokine that seems likely to play a role in inflammation and host defense. Little is known about the regulation of IL-32 production by primary cells of the immune system. METHODS AND FINDINGS: In the present study, freshly obtained human peripheral blood mononuclear cells were stimulated with different Toll-like receptor (TLR) agonists, and gene expression and synthesis of IL-32 was determined. We demonstrate that the TLR4 agonist lipopolysaccharide induces moderate (4-fold) production of IL-32, whereas agonists of TLR2, TLR3, TLR5, or TLR9, each of which strongly induced tumor necrosis factor α and IL-6, did not stimulate IL-32 production. However, the greatest amount of IL-32 was induced by the mycobacteria Mycobacterium tuberculosis and M. bovis BCG (20-fold over unstimulated cells). IL-32-induced synthesis by either lipopolysaccharide or mycobacteria remains entirely cell-associated in monocytes; moreover, steady-state mRNA levels are present in unstimulated monocytes without translation into IL-32 protein, similar to other cytokines lacking a signal peptide. IL-32 production induced by M. tuberculosis is dependent on endogenous interferon-γ (IFNγ); endogenous IFNγ is, in turn, dependent on M. tuberculosis–induced IL-18 via caspase-1. CONCLUSIONS: In conclusion, IL-32 is a cell-associated proinflammatory cytokine, which is specifically stimulated by mycobacteria through a caspase-1- and IL-18-dependent production of IFNγ

Deletion of Nlrp3 protects from inflammation-induced skeletal muscle atrophy

BACKGROUND: Critically ill patients develop atrophic muscle failure, which increases morbidity and mortality. Interleukin-1β (IL-1β) is activated early in sepsis. Whether IL-1β acts directly on muscle cells and whether its inhibition prevents atrophy is unknown. We aimed to investigate if IL-1β activation via the Nlrp3 inflammasome is involved in inflammation-induced atrophy. METHODS: We performed an experimental study and prospective animal trial. The effect of IL-1β on differentiated C2C12 muscle cells was investigated by analyzing gene-and-protein expression, and atrophy response. Polymicrobial sepsis was induced by cecum ligation and puncture surgery in Nlrp3 knockout and wild type mice. Skeletal muscle morphology, gene and protein expression, and atrophy markers were used to analyze the atrophy response. Immunostaining and reporter-gene assays showed that IL-1β signaling is contained and active in myocytes. RESULTS: Immunostaining and reporter gene assays showed that IL-1β signaling is contained and active in myocytes. IL-1β increased Il6 and atrogene gene expression resulting in myocyte atrophy. Nlrp3 knockout mice showed reduced IL-1β serum levels in sepsis. As determined by muscle morphology, organ weights, gene expression, and protein content, muscle atrophy was attenuated in septic Nlrp3 knockout mice, compared to septic wild-type mice 96 h after surgery. CONCLUSIONS: IL-1β directly acts on myocytes to cause atrophy in sepsis. Inhibition of IL-1β activation by targeting Nlrp3 could be useful to prevent inflammation-induced muscle failure in critically ill patients

Distinct Mechanisms for Induction and Tolerance Regulate the Immediate Early Genes Encoding Interleukin 1β and Tumor Necrosis Factor α

Interleukin-1β and Tumor Necrosis Factor α play related, but distinct, roles in immunity and disease. Our study revealed major mechanistic distinctions in the Toll-like receptor (TLR) signaling-dependent induction for the rapidly expressed genes (IL1B and TNF) coding for these two cytokines. Prior to induction, TNF exhibited pre-bound TATA Binding Protein (TBP) and paused RNA Polymerase II (Pol II), hallmarks of poised immediate-early (IE) genes. In contrast, unstimulated IL1B displayed very low levels of both TBP and paused Pol II, requiring the lineage-specific Spi-1/PU.1 (Spi1) transcription factor as an anchor for induction-dependent interaction with two TLR-activated transcription factors, C/EBPβ and NF-κB. Activation and DNA binding of these two pre-expressed factors resulted in de novo recruitment of TBP and Pol II to IL1B in concert with a permissive state for elongation mediated by the recruitment of elongation factor P-TEFb. This Spi1-dependent mechanism for IL1B transcription, which is unique for a rapidly-induced/poised IE gene, was more dependent upon P-TEFb than was the case for the TNF gene. Furthermore, the dependence on phosphoinositide 3-kinase for P-TEFb recruitment to IL1B paralleled a greater sensitivity to the metabolic state of the cell and a lower sensitivity to the phenomenon of endotoxin tolerance than was evident for TNF. Such differences in induction mechanisms argue against the prevailing paradigm that all IE genes possess paused Pol II and may further delineate the specific roles played by each of these rapidly expressed immune modulators. © 2013 Adamik et al