title: Genome-wide transcriptional profiling of mononuclear phagocytes recruited to mouse lungs in response to alveolar challenge with the TLR2 agonist Pam3CSK4.
abstract: Compared with the Toll-like receptor 4 (TLR4) ligand LPS restricted to gram-negative bacteria, few studies have addressed induction of lung inflammation and concomitant leukocyte recruitment in response to TLR2 ligands. This study is the first report showing that selective TLR2 stimulation by its ligand Pam(3)-Cys-Ser-Lys-Lys-Lys-Lys-OH (Pam(3)CSK(4)) within the alveolar compartment promoted lung inflammation in mice and induced the migration of circulatory immune cells including mononuclear phagocytes into the inflamed alveolar space. By using the transgenic CX(3)CR1(+/GFP) mouse strain for high-purity sorting of circulating and alveolar recruited mononuclear phagocytes together with SMART preamplification and whole genome oligonucleotide microarray techniques, we found that alveolar trafficking of mononuclear phagocytes was associated with profound changes of their gene expression profiles (approximately 900 differentially regulated genes postrecruitment). In particular, alveolar recruited mononuclear phagocytes showed upregulated transcripts of genes encoding cytokines/chemokines and pattern recognition receptor (PRR)-associated molecules. Notably, we observed a dynamic change of the genetic program of recruited mononuclear phagocytes obtained from bronchoalveolar lavage fluid at different time points (24 vs. 48 h) post-Pam(3)CSK(4) challenge. In early alveolar recruited mononuclear phagocytes, mRNA levels of both proinflammatory (e.g., TNF-alpha, CCL2, and IL-6) and central anti-inflammatory/ proresolution [e.g., IL-1-receptor antagonist (IL-1RN), CD200 receptor (CD200R), IL-1 receptor-associated kinase (IRAK-M), IL-10, and Bcl-2-associated X protein (Bax)] mediators were found to be highly upregulated simultaneously. In corresponding cells recruited until later time points, transcript levels of anti-inflammatory/proresolution molecules persisted at the same level, whereas mRNA levels of proinflammatory mediators were found to decline. Collectively, our in vivo study identifies genetic programs by which alveolar recruited mononuclear phagocytes may contribute to the development and termination of pneumonia caused by gram-positive bacteria.
authors.affiliation: Dept. of Internal Medicine, Division of Pulmonary and Critical Care Medicine and Infectious Diseases, Hannover Medical School, Carl-Neuberg-Str.1, 30625 Hannover, Germany. cabanski.maciej@mh-hannover.de
authors.forename: Maciej
authors.initials: M
authors.lastname: Cabanski
authors.forename: Jochen
authors.initials: J
authors.lastname: Wilhelm
authors.forename: Zbigniew
authors.initials: Z
authors.lastname: Zaslona
authors.forename: Mirko
authors.initials: M
authors.lastname: Steinmüller
authors.forename: Ludger
authors.initials: L
authors.lastname: Fink
authors.forename: Werner
authors.initials: W
authors.lastname: Seeger
authors.forename: Jürgen
authors.initials: J
authors.lastname: Lohmeyer
mesh_terms: D000818:Animals; D001992:Bronchoalveolar Lavage Fluid / Q000737:chemistry; D000073883:CX3C Chemokine Receptor 1; D002465:Cell Movement; D016207:Cytokines / Q000276:immunology / Q000378:metabolism; D005434:Flow Cytometry; D020869:Gene Expression Profiling; D007249:Inflammation / Q000209:etiology* / Q000473:pathology*; D055666:Lipopeptides / Q000494:pharmacology; D008168:Lung / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008822:Mice, Transgenic; D020411:Oligonucleotide Array Sequence Analysis; D010586:Phagocytes / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D011650:Pulmonary Alveoli / Q000276:immunology* / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D019707:Receptors, Chemokine / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D051195:Toll-Like Receptor 2 / Q000819:agonists* / Q000378:metabolism
chemical_list: D000073883:CX3C Chemokine Receptor 1; C471885:Cx3cr1 protein, mouse; D016207:Cytokines; D055666:Lipopeptides; C508075:Pam(3)CSK(4) peptide; D012333:RNA, Messenger; D019707:Receptors, Chemokine; D051195:Toll-Like Receptor 2