title: Streptococcus pneumoniae induces human β-defensin-2 and -3 in human lung epithelium.
abstract: Streptococcus pneumoniae is an important causative agent of pneumonia in humans. Pulmonary epithelial surfaces constitutes not only a mechanical barrier against invading pathogens but also essentially contribute to innate immunity by producing antimicrobial peptides such as human β-defensin-2 (hBD-2) and -3 (hBD-3). In this study the authors demonstrated that pneumococci induced hBD-2 and hBD-3 expression in human pulmonary epithelial cells. Further analysis indicated an essential role of Toll-like receptor 2 (TLR2) for the expression of both peptides in infected pulmonary epithelial cells. Whereas the hBD-2 release was controlled by the phosphoinositide 3-kinase (PI3K) and the transcription factor nuclear factor kappa B (NF-κB), hBD-3 was triggered via the c-Jun N-terminal kinase (JNK)-activator protein 1 (AP-1) pathway. Additionally, the authors showed that exogenous hBD-2 as well as hBD-3 elicited a strong antimicrobial effect on S. pneumoniae. Thus, differential regulation of the expression of hBD-2 and hBD-3 might play an important role in pneumococci pneumonia.
authors.affiliation: Department of Internal Medicine/Infectious Diseases and Pulmonary Medicine, Charité-Universitätsmedizin Berlin,   Berlin,   Germany.
authors.forename: Stefanie
authors.initials: S
authors.lastname: Scharf
authors.forename: Janine
authors.initials: J
authors.lastname: Zahlten
authors.forename: Kolja
authors.initials: K
authors.lastname: Szymanski
authors.forename: Stefan
authors.initials: S
authors.lastname: Hippenstiel
authors.forename: Norbert
authors.initials: N
authors.lastname: Suttorp
authors.forename: Philippe Dje
authors.initials: PD
authors.lastname: N'Guessan
mesh_terms: D056809:Alveolar Epithelial Cells / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D006801:Humans; D007113:Immunity, Innate; D008168:Lung / Q000276:immunology / Q000378:metabolism / Q000382:microbiology*; D016328:NF-kappa B / Q000378:metabolism; D058539:Phosphatidylinositol 3-Kinase / Q000378:metabolism; D016755:Proto-Oncogene Proteins c-jun / Q000378:metabolism; D013296:Streptococcus pneumoniae / Q000276:immunology / Q000472:pathogenicity*; D051195:Toll-Like Receptor 2 / Q000378:metabolism; D018808:Transcription Factor AP-1 / Q000378:metabolism; D023083:beta-Defensins / Q000096:biosynthesis*
chemical_list: C422950:DEFB103A protein, human; C106641:DEFB4A protein, human; D016328:NF-kappa B; D016755:Proto-Oncogene Proteins c-jun; C495342:TLR2 protein, human; D051195:Toll-Like Receptor 2; D018808:Transcription Factor AP-1; D023083:beta-Defensins; D058539:Phosphatidylinositol 3-Kinase