Document Detail

Innate immune collectin surfactant protein D simultaneously binds both neutrophil extracellular traps and carbohydrate ligands and promotes bacterial trapping.
MedLine Citation:
PMID:  21724991     Owner:  NLM     Status:  MEDLINE    
Neutrophils release DNA-based extracellular traps to capture and kill bacteria. The mechanism(s) and proteins that promote neutrophil extracellular trap (NET)-mediated bacterial trapping are not clearly established. Surfactant protein D (SP-D) is an innate immune collectin present in many mucosal surfaces. We hypothesized that SP-D can bind both the pathogens and NETs to augment NET-mediated bacterial trapping. To test this hypothesis, we used LPS and Pseudomonas aeruginosa pneumonia mouse models and performed in vivo and ex vivo assays. In this study, we show that NETs are produced by the neutrophils recruited to the airways in response to the bacterial ligand. Notably, NETs are detected as short fragments of DNA-protein complexes in the airways as opposed to the long stringlike structures seen in ex vivo cultures. SP-D recognizes both the short NET fragments and the long NET DNA structures. SP-D-NET copurification studies further show that SP-D can simultaneously recognize NETs and carbohydrate ligands in vivo. Similar to the LPS model, soluble DNA-protein complexes and increased amounts of SP-D are detected in the murine model of P. aeruginosa pneumonia. We then tested the effect of SP-D on NET-mediated trapping of P. aeruginosa by means of Western blots, fluorescence microscopy, and scanning electron microscopy. Results of these experiments show that SP-D microagglutinates P. aeruginosa and allows an efficient bacterial trapping by NETs. Collectively, these findings provide a unique biological relevance for SP-D-DNA interactions and places SP-D as an important innate immune protein that promotes bacterial trapping by NETs during neutrophil-mediated host defense.
David Nobuhiro Douda; Richard Jackson; Hartmut Grasemann; Nades Palaniyar
Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't     Date:  2011-07-01
Journal Detail:
Title:  Journal of immunology (Baltimore, Md. : 1950)     Volume:  187     ISSN:  1550-6606     ISO Abbreviation:  J. Immunol.     Publication Date:  2011 Aug 
Date Detail:
Created Date:  2011-08-03     Completed Date:  2011-09-29     Revised Date:  2012-01-27    
Medline Journal Info:
Nlm Unique ID:  2985117R     Medline TA:  J Immunol     Country:  United States    
Other Details:
Languages:  eng     Pagination:  1856-65     Citation Subset:  AIM; IM    
Program in Physiology and Experimental Medicine, SickKids Research Institute, Toronto, Ontario M5G 1X8, Canada.
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MeSH Terms
Carbohydrates / immunology*
DNA / immunology*,  metabolism
Disease Models, Animal
Immunity, Innate / physiology*
Mice, Inbred BALB C
Neutrophils / immunology*,  metabolism,  microbiology
Pneumonia, Bacterial / immunology*,  metabolism
Pseudomonas Infections / immunology*,  metabolism,  microbiology
Pseudomonas aeruginosa / immunology*,  metabolism
Pulmonary Surfactant-Associated Protein D / immunology*,  metabolism
Grant Support
84312//Canadian Institutes of Health Research
Reg. No./Substance:
0/Carbohydrates; 0/Pulmonary Surfactant-Associated Protein D; 9007-49-2/DNA
Comment In:
J Immunol. 2012 Jan 1;188(1):3; author reply 3-4   [PMID:  22187479 ]

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine

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