Extracellular Hsp72, an endogenous DAMP, is released by virally infected airway epithelial cells and activates neutrophils via Toll-like receptor (TLR)-4

<p>Abstract</p> <p>Background</p> <p>Neutrophils play an important role in the pathophysiology of RSV, though RSV does not appear to directly activate neutrophils in the lower airways. Therefore locally produced cytokines or other molecules released by virally-infected airway epithelial cells are likely responsible for recruiting and activating neutrophils. Heat shock proteins (HSPs) are generally regarded as intracellular proteins acting as molecular chaperones; however, HSP72 can also be released from cells, and the implications of this release are not fully understood.</p> <p>Methods</p> <p>Human bronchial epithelial cells (16HBE14o-) were infected with RSV and Hsp72 levels were measured by Western blot and ELISA. Tracheal aspirates were obtained from critically ill children infected with RSV and analyzed for Hsp72 levels by ELISA. Primary human neutrophils and differentiated HL-60 cells were cultured with Hsp72 and supernatants analyzed for cytokine production. In some cases, cells were pretreated with polymyxin B prior to treatment with Hsp72. IκBα was assessed by Western blot and EMSA's were performed to determine NF-κB activation. HL-60 cells were pretreated with neutralizing antibody against TLR4 prior to Hsp72 treatment. Neutrophils were harvested from the bone marrow of wild type or TLR4-deficient mice prior to treatment with Hsp72.</p> <p>Results</p> <p>Infection of 16HBE14o- with RSV showed an induction of intracellular Hsp72 levels as well as extracellular release of Hsp72. Primary human neutrophils from normal donors and differentiated HL-60 cells treated with increasing concentrations of Hsp72 resulted in increased cytokine (IL-8 and TNFα) production. This effect was independent of the low levels of endotoxin in the Hsp72 preparation. Hsp72 mediated cytokine production via activation of NF-κB translocation and DNA binding. Using bone marrow-derived neutrophils from wild type and TLR4-mutant mice, we showed that Hsp72 directly activates neutrophil-derived cytokine production via the activation of TLR4.</p> <p>Conclusion</p> <p>Collectively these data suggest that extracellular Hsp72 is released from virally infected airway epithelial cells resulting in the recruitment and activation of neutrophils.</p

ChemR23 Dampens Lung Inflammation and Enhances Anti-viral Immunity in a Mouse Model of Acute Viral Pneumonia

Viral diseases of the respiratory tract, which include influenza pandemic, children acute bronchiolitis, and viral pneumonia of the elderly, represent major health problems. Plasmacytoid dendritic cells play an important role in anti-viral immunity, and these cells were recently shown to express ChemR23, the receptor for the chemoattractant protein chemerin, which is expressed by epithelial cells in the lung. Our aim was to determine the role played by the chemerin/ChemR23 system in the physiopathology of viral pneumonia, using the pneumonia virus of mice (PVM) as a model. Wild-type and ChemR23 knock-out mice were infected by PVM and followed for functional and inflammatory parameters. ChemR23−/− mice displayed higher mortality/morbidity, alteration of lung function, delayed viral clearance and increased neutrophilic infiltration. We demonstrated in these mice a lower recruitment of plasmacytoid dendritic cells and a reduction in type I interferon production. The role of plasmacytoid dendritic cells was further addressed by performing depletion and adoptive transfer experiments as well as by the generation of chimeric mice, demonstrating two opposite effects of the chemerin/ChemR23 system. First, the ChemR23-dependent recruitment of plasmacytoid dendritic cells contributes to adaptive immune responses and viral clearance, but also enhances the inflammatory response. Second, increased morbidity/mortality in ChemR23−/− mice is not due to defective plasmacytoid dendritic cells recruitment, but rather to the loss of an anti-inflammatory pathway involving ChemR23 expressed by non-leukocytic cells. The chemerin/ChemR23 system plays important roles in the physiopathology of viral pneumonia, and might therefore be considered as a therapeutic target for anti-viral and anti-inflammatory therapies

Profile of gastrointestinal involvement in patients with systemic sclerosis

Systemic sclerosis (SSc) is a chronic autoimmune connective tissue disease. Of the numerous organ manifestations, involvement of the upper and lower gastrointestinal tract (GIT) appears to be the most frequent with regard to the clinical symptoms. However, as the frequency and clinical relevance of GI involvement in patients with SSc are not known in detail, the German network of the systemic sclerosis (DNSS) has developed a detailed questionnaire to evaluate the extent and profile of gastrointestinal involvement in SSc patients. The multi-symptom questionnaire was used at baseline and after 1 year in registered patients of the DNSS. In addition, the results were compared with gastrointestinal disorders in patients with SSc and other rheumatic diseases, as well as with the medical history of the patients. In total, 90 patients were included in the study. The results of the study show that in reality, a much higher (nearly all) percentage of (98,9%) patients than expected suffer from GI-symptoms, regardless of the stage of their disease. Of these, meteorism (87,8%) was the most common followed by coughing/sore voice (77,8%), heartburn (daytime 68,9%, nighttime 53,3%), diarrhea (67,8%), stomach ache (68,9%) and nausea (61,1%). Although SSc patients were treated according to the respective recommendations, only limited improvements with regard to GI-symptoms could be achieved after 1 year of follow-up. In addition, the study revealed that the multi-symptom questionnaire is a useful tool to contribute to identify the gastrointestinal sequelae in systemic sclerosis