IL-1α/IL-1R1 expression in chronic obstructive pulmonary disease and mechanistic relevance to smoke-induced neutrophilia in mice

Background

Cigarette smoking is the main risk factor for the development of chronic obstructive pulmonary disease (COPD), a major cause of morbidity and mortality worldwide. Despite this, the cellular and molecular mechanisms that contribute to COPD pathogenesis are still poorly understood.

Methodology and Principal Findings

The objective of this study was to assess IL-1 α and β expression in COPD patients and to investigate their respective roles in perpetuating cigarette smoke-induced inflammation. Functional studies were pursued in smoke-exposed mice using gene-deficient animals, as well as blocking antibodies for IL-1α and β. Here, we demonstrate an underappreciated role for IL-1α expression in COPD. While a strong correlation existed between IL-1α and β levels in patients during stable disease and periods of exacerbation, neutrophilic inflammation was shown to be IL-1α-dependent, and IL-1β- and caspase-1-independent in a murine model of cigarette smoke exposure. As IL-1α was predominantly expressed by hematopoietic cells in COPD patients and in mice exposed to cigarette smoke, studies pursued in bone marrow chimeric mice demonstrated that the crosstalk between IL-1α+ hematopoietic cells and the IL-1R1+ epithelial cells regulates smoke-induced inflammation. IL-1α/IL-1R1-dependent activation of the airway epithelium also led to exacerbated inflammatory responses in H1N1 influenza virus infected smoke-exposed mice, a previously reported model of COPD exacerbation.

Conclusions and Significance

This study provides compelling evidence that IL-1α is central to the initiation of smoke-induced neutrophilic inflammation and suggests that IL-1α/IL-1R1 targeted therapies may be relevant for limiting inflammation and exacerbations in COPD.     

Ubiquitin-mediated internalization of connexin43 is independent of the canonical endocytic tyrosine-sorting signal

Gap junctions are specialized cell-cell contacts that provide direct intercellular communication between eukaryotic cells. The tyrosine-sorting signal (YXX?), present at amino acids 286-289 of Cx43 (connexin43), has been implicated in the internalization of the protein. In recent years, ubiquitination of Cx43 has also been proposed to regulate gap junction intercellular communication; however, the underlying mechanism and molecular players involved remain elusive. In the present study, we demonstrate that ubiquitinated Cx43 is internalized through a mechanism that is independent of the YXX? signal. Indeed, expression of a Cx43-Ub (ubiquitin) chimaera was shown to drive the internalization of a mutant Cx43 in which the YXX? motif was eliminated. Immunofluorescence, cycloheximide-chase and cell-surface-protein biotinylation experiments demonstrate that oligomerization of Cx43-Ub into hemichannels containing wild-type Cx43 or mutant Cx43Y286A is sufficient to drive the internalization of the protein. Furthermore, the internalization of Cx43 induced by Cx43-Ub was shown to depend on its interaction with epidermal growth factor receptor substrate 15.     

Increased hepatic expression of TLR2 and TLR4 in the hepatic inflammation-fibrosis-carcinoma sequence

We evaluated expression of TLR2, TLR4 and proinflammatory genes [NF-κB, TNF-α, cyclooxygenase-2 (COX-2)] in liver samples of patients in different stages of liver disease. Fifteen patients with unexplained transaminases elevation (reference group), 22 with viral chronic hepatitis (hepatitis group), 14 with virus-induced severe fibrosis/cirrhosis (cirrhosis group) and 10 with hepatocarcinoma (hepatocarcinoma group) were consecutively included in the study. Quantification of TLR2, TLR4, NF-κB, TNF-α and COX-2 mRNA was done by real-time RT-PCR and TLR2 and TLR4 protein expression was evaluated by immunohistochemistry. Compared with reference, TLR2 and TLR4 mRNA was increased in hepatitis (TLR2: 2.66?±?0.69; TLR4: 3.11?±?0.79; P?相似文献   

A novel heterozygous mutation of the AIRE gene in a patient with autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED)

Background

Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome (APECED) is an autosomal recessive disease due to mutations of the autoimmune regulator (AIRE) gene. Typical manifestations include candidiasis, Addison's disease, and hypoparathyroidism. Type 1 diabetes, alopecia, vitiligo, ectodermal dystrophy, celiac disease and other intestinal dysfunctions, chronic atrophic gastritis, chronic active hepatitis, autoimmune thyroid disorders, pernicious anemia and premature ovarian failure are other rare associated diseases although other conditions have been associated with APECED.

Case presentation

What follows is the clinical, endocrinological and molecular data of a female APECED patient coming from Lithuania. The patient was affected by chronic mucocutaneous candidiasis, hypoparathyroidism and pre-clinical Addison's disease. Using direct sequencing of all the 14 exons of the AIRE gene in the patient's DNA, we identified in exon 6 the known mutation c.769 C>T (p.Arg257X) in compound heterozygosity with the newly discovered mutation c.1214delC (p.Pro405fs) in exon 10. The novel mutation results in a frameshift that is predicted to alter the sequence of the protein starting from amino acid 405 as well as to cause its premature truncation, therefore a non-functional Aire protein.

Conclusions

A novel mutation has been described in a patient with APECED with classical clinical components, found in compound heterozygosity with the c.769 C>T variation. Expanded epidemiological investigations based on AIRE gene sequencing are necessary to verify the relevancy of the novel mutation to APECED etiopathogenesis in the Lithuanian population and to prove its diagnostic efficacy in association with clinical and immunological findings.     

Heat-Resistance and Heat-Shock Response in the Nosocomial Pathogen <Emphasis Type="Italic">Enterococcus faecium</Emphasis>

We have characterized the heat-shock response of the nosocomial pathogen Enterococcus faecium. The growth of E. faecium cells was analyzed at different temperatures; little growth was observed at 50°C, and no growth at 52°C or 55°C. In agreement, a marked decrease of general protein synthesis was observed at 52°C, and very light synthesis was detected at 55°C. The heat resistance of E. faecium cells was analyzed by measuring the survival at temperatures higher than 52°C and, after 2 h of incubation, viable cells were still observed at 70°C. By Western blot analysis, two heat-induced proteins were identified as GroEL (65 kDa) and DnaK (75 kDa). Only one isoform for either GroEL or DnaK was found. The gene expression of these heat-shock proteins was also analyzed by pulsed-labeled experiments. The heat-induced proteins showed an increased rate of synthesis during the first 5 min, reaching the highest level of induction after 10 min and returning to the steady-state level after 20 min of heat treatment. Received: 29 March 2002 / Accepted: 5 July 2002     

Habitat attribute similarities reduce impacts of land‐use conversion on seed removal

Changes in land use strongly influence habitat attributes (e.g., herbaceous ground cover and tree richness) and can consequently affect ecological functions. Most studies have focused on the response of these ecological functions to land‐use changes within only a single vegetation type. These studies have often focused solely on agricultural conversion of forests, making it nearly impossible to draw general conclusions across other vegetation types or with other land‐use changes (e.g., afforestation). We examined the consequences of agricultural conversion for seed removal by ants in native grassland, savanna, and savanna‐forest habitats that had been transformed to planted pastures (Brachiaria decumbens) and tree plantations (Eucalyptus spp.) and explored if changes in seed removal were correlated with differences in habitat attributes between habitat types. We found that land‐use changes affected seed removal across the tree cover gradient and that the magnitude of impact was influenced by similarity in habitat attributes between native and converted habitats, being greater where there was afforestation (Eucalyptus spp in grassland and savanna). Herbaceous ground cover, soil hardness, and tree richness were the most important habitat attributes that correlated with differences in seed removal. Our results reveal that the magnitude of impact of land‐use changes on seed removal varies depending on native vegetation type and is associated with the type of habitat attribute change. Our findings have implications for biodiversity in tropical grassy systems: afforestation can have a greater detrimental impact on ecological function than tree loss.     

Spectroscopic and kinetic analyses reveal the pyridoxal 5'-phosphate binding mode and the catalytic features of Treponema denticola cystalysin

To obtain insight into the functional properties of Treponema denticola cystalysin, we have analyzed the pH- and ligand-induced spectral transitions, the pH dependence of the kinetic parameters, and the substrate specificity of the purified enzyme. The absorption spectrum of cystalysin has maxima at 418 and 320 nm. The 320 nm band increases at high pH, while the 418 nm band decreases; the apparent pK(spec) of this spectral transition is about 8.4. Cystalysin emitted fluorescence at 367 and 504 nm upon excitation at 320 and 418 nm, respectively. The pH profile for the 367 nm emission intensity increases above a single pK of approximately 8.4. On this basis, the 418 and 320 nm absorbances have been attributed to the ketoenamine and substituted aldamine, respectively. The pH dependence of both log k(cat) and log k(cat)/K(m) for alpha,beta-elimination reaction indicates that a single ionizing group with a pK value of approximately 6.6 must be unprotonated to achieve maximum velocity. This implies that cystalysin is more catalytically competent in alkaline solution where a remarkable portion of its coenzyme exists as inactive aldamine structure. Binding of substrates or substrate analogues to the enzyme over the pH range 6-9.5 converts both the 418 and 320 nm bands into an absorbing band at 429 nm, assigned to the external aldimine in the ketoenamine form. All these data suggest that the equilibrium from the inactive aldamine form of the coenzyme shifts to the active ketoenamine form on substrate binding. In addition, reinvestigation of the substrate spectrum of alpha,beta-elimination indicates that cystalysin is a cyst(e)ine C-S lyase rather than a cysteine desulfhydrase as claimed previously.     

An Assessment of a Small Urban Stream Restoration Project in Northern California

Stream restoration projects have become increasingly common, and the need for systematic post‐project evaluation, particularly for small‐scale projects, is evident. This study describes how a 70‐m restored reach of a small urban stream, Baxter Creek (in Poinsett Park, El Cerrito, California), was quickly and inexpensively evaluated using habitat, biological, and resident‐attitude assessments. The restoration involved opening a previously culverted channel, planting riparian vegetation, and adding in‐stream step‐pool sequences and sinuosity. Replicated benthic macroinvertebrate samples from the restored site and an upstream unrestored site were compared using several metrics, including taxa richness and a biotic index. Both biological and habitat quality improved in the restored compared with the unrestored section. However, when compared with a creek restored 12 years before, habitat condition was of lower quality in the recently restored creek. A survey of the neighborhood residents indicated that, overall, they were pleased with the restored creek site. The approach used in this demonstration project may be applicable to other small‐scale evaluations of urban stream restorations.