Tuyển tập các báo cáo nghiên cứu về y học được đăng trên tạp chí y học 'Respiratory Research cung cấp cho các bạn kiến thức về ngành y đề tài:Legionella pneumophila induces human beta Defensin-3 in pulmonary cells. | Scharf et al. Respiratory Research 2010 11 93 http content 11 1 93 RESPIRATORY RESEARCH RESEARCH Open Access Legionella pneumophila induces human beta Defensin-3 in pulmonary cells Stefanie Scharf 1 Kremena Vardarova1 Friederike Lang1 Bernd Schmeck1 2 Bastian Opitz1 Antje Flieger3 Klaus Heuner4 Stefan Hippenstiel1 Norbert Suttorp1 and Philippe D N Guessan 1 Abstract Background Legionella pneumophila is an important causative agent of severe pneumonia in humans. Human alveolar epithelium and macrophages are effective barriers for inhaled microorganisms and actively participate in the initiation of innate host defense. The beta defensin-3 hBD-3 an antimicrobial peptide is an important component of the innate immune response of the human lung. Therefore we hypothesize that hBD-3 might be important for immune defense towards L pneumophila. Methods We investigated the effects of L. pneumophila and different TLR agonists on pulmonary cells in regard to hBD-3 expression by ELISA. Furthermore siRNA-mediated inhibition of TLRs as well as chemical inhibition of potential downstream signaling molecules was used for functional analysis. Results L. pneumophila induced release of hBD-3 in pulmonary epithelium and alveolar macrophages. A similar response was observed when epithelial cells were treated with different TLR agonists. Inhibition of TLR2 TLR5 and TLR9 expression led to a decreased hBD-3 expression. Furthermore expression of hBD-3 was mediated through a JNK dependent activation of AP-1 c-Jun but appeared to be independent of NF-kB. Additionally we demonstrate that hBD-3 elicited a strong antimicrobial effect on L. pneumophila replication. Conclusions Taken together human pulmonary cells produce hBD-3 upon L. pneumophila infection via a TLR-JNK-AP-1-dependent pathway which may contribute to an efficient innate immune defense. Background Legionella pneumophila is the causative agent of Legionnaires disease a severe pneumonia with high mortality 1
