| Pulmonary collectins protect macrophages against pore-forming activity of Legionella pneumophila and suppress its intracellular growth. | |
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MedLine Citation:
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PMID: 20056602 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Pulmonary collectins, surfactant proteins A (SP-A) and D (SP-D), play important roles in innate immunity of the lung. Legionella pneumophila is a bacterial respiratory pathogen that can replicate within macrophages and causes opportunistic infections. L. pneumophila possesses cytolytic activity, resulting from insertion of pores in the macrophage membrane upon contact. We examined whether pulmonary collectins play protective roles against L. pneumophila infection. SP-A and SP-D bound to L. pneumophila and its lipopolysaccharide (LPS) and inhibited the bacterial growth in a Ca(2+)-dependent manner. The addition of LPS in the culture blocked the inhibitory effects on L. pneumophila growth by the collectins, indicating the importance of LPS-collectin interaction. When differentiated THP-1 cells were infected with L. pneumophila in the presence of SP-A and SP-D, the number of permeable cells was significantly decreased, indicating that pulmonary collectins inhibit pore-forming activity of L. pneumophila. The number of live bacteria within the macrophages on days 1-4 after infection was significantly decreased when infection was performed in the presence of pulmonary collectins. The phagocytosis experiments with the pH-sensitive dye-labeled bacteria revealed that pulmonary collectins promoted bacterial localization to an acidic compartment. In addition, SP-A and SP-D significantly increased the number of L. pneumophila co-localized with LAMP-1. These results indicate that pulmonary collectins protect macrophages against contact-dependent cytolytic activity of L. pneumophila and suppress intracellular growth of the phagocytosed bacteria. The promotion of lysosomal fusion with Legionella-containing phagosomes constitutes a likely mechanism of L. pneumophila growth suppression by the collectins. |
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Authors:
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Kaku Sawada; Shigeru Ariki; Takashi Kojima; Atsushi Saito; Masami Yamazoe; Chiaki Nishitani; Takeyuki Shimizu; Motoko Takahashi; Hiroaki Mitsuzawa; Shin-Ichi Yokota; Norimasa Sawada; Nobuhiro Fujii; Hiroki Takahashi; Yoshio Kuroki |
Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't Date: 2010-01-07 |
Journal Detail:
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Title: The Journal of biological chemistry Volume: 285 ISSN: 1083-351X ISO Abbreviation: J. Biol. Chem. Publication Date: 2010 Mar |
Date Detail:
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Created Date: 2010-03-08 Completed Date: 2010-04-15 Revised Date: 2011-07-26 |
Medline Journal Info:
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Nlm Unique ID: 2985121R Medline TA: J Biol Chem Country: United States |
Other Details:
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Languages: eng Pagination: 8434-43 Citation Subset: IM |
Affiliation:
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Departments of Biochemistry, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan. |
Export Citation:
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| MeSH Terms | |
Descriptor/Qualifier:
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Calcium
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metabolism Carbohydrates / immunology Cell Line Cell Membrane / immunology Humans Legionella pneumophila / growth & development, immunology* Legionnaires' Disease / immunology* Lipopolysaccharides / pharmacology Lysosomes / immunology Macrophages, Alveolar / microbiology* Monocytes / cytology Phagocytosis / immunology Pulmonary Surfactant-Associated Protein A / immunology* Pulmonary Surfactant-Associated Protein D / immunology* |
| Chemical | |
Reg. No./Substance:
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0/Carbohydrates; 0/Lipopolysaccharides; 0/Pulmonary Surfactant-Associated Protein A; 0/Pulmonary Surfactant-Associated Protein D; 0/SFTPA1 protein, human; 7440-70-2/Calcium |
| Comments/Corrections | |
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