Linked Life Data

14993215

Source:http://linkedlifedata.com/resource/pubmed/id/14993215

Statements in which the resource exists as a subject.
PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
20
pubmed:dateCreated
2004-5-10
pubmed:abstractText
Pulmonary surfactant proteins A (SP-A) and D (SP-D), members of the collectin family, play important roles in the innate immune system of the lung. Here, we show that SP-A but not SP-D augmented phagocytosis of Streptococcus pneumoniae by alveolar macrophages, independent of its binding to the bacteria. Analysis of the SP-A/SP-D chimeras, in which progressively longer carboxyl-terminal regions of SP-A were replaced with the corresponding SP-D regions, has revealed that the SP-D region Gly(346)-Phe(355) can be substituted for the SP-A region Leu(219)-Phe(228) without altering the SP-A activity of enhancing the phagocytosis and that the SP-A region Cys(204)-Cys(218) is required for the SP-A-mediated phagocytosis. Acetylated low density lipoprotein significantly reduced the SP-A-stimulated uptake of the bacteria. SP-A failed to enhance the phagocytosis of S. pneumoniae by alveolar macrophages derived from scavenger receptor A (SR-A)-deficient mice, demonstrating that SP-A augments SRA-mediated phagocytosis. Preincubation of macrophages with SP-A at 37 degrees C but not at 4 degrees C stimulated the phagocytosis. The SP-A-mediated enhanced phagocytosis was not inhibited by the presence of cycloheximide. SP-A increased cell surface localization of SR-A that was inhibitable by apigenin, a casein kinase 2 (CK2) inhibitor. SP-A-treated macrophages exhibited significantly greater binding of acetylated low density lipoprotein than nontreated cells. The SP-A-stimulated phagocytosis was also abolished by apigenin. In addition, SP-A stimulated CK2 activity. These results demonstrate that SP-A enhances the phagocytosis of S. pneumoniae by alveolar macrophages through a CK2-dependent increase of cell surface SR-A localization. This study reveals a novel mechanism of bacterial clearance by alveolar macrophages.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
IM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
May
pubmed:issn
0021-9258
pubmed:author
pubmed:issnType
Print
pubmed:day
14
pubmed:volume
279
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
21421-30
pubmed:dateRevised
2009-11-19
pubmed:meshHeading
pubmed-meshheading:14993215-Acetylation, pubmed-meshheading:14993215-Amino Acid Substitution, pubmed-meshheading:14993215-Animals, pubmed-meshheading:14993215-Casein Kinase II, pubmed-meshheading:14993215-Cell Membrane, pubmed-meshheading:14993215-Kinetics, pubmed-meshheading:14993215-Lipoproteins, LDL, pubmed-meshheading:14993215-Macrophages, Alveolar, pubmed-meshheading:14993215-Phagocytosis, pubmed-meshheading:14993215-Protein-Serine-Threonine Kinases, pubmed-meshheading:14993215-Pulmonary Surfactant-Associated Protein A, pubmed-meshheading:14993215-Pulmonary Surfactant-Associated Protein D, pubmed-meshheading:14993215-Rats, pubmed-meshheading:14993215-Receptors, Immunologic, pubmed-meshheading:14993215-Receptors, Scavenger, pubmed-meshheading:14993215-Recombinant Proteins, pubmed-meshheading:14993215-Scavenger Receptors, Class A, pubmed-meshheading:14993215-Streptococcus pneumoniae
pubmed:year
2004
pubmed:articleTitle
Pulmonary surfactant protein A augments the phagocytosis of Streptococcus pneumoniae by alveolar macrophages through a casein kinase 2-dependent increase of cell surface localization of scavenger receptor A.
pubmed:affiliation
Department of Biochemistry, Sapporo Medical University School of Medicine, Sapporo 060-8556, Japan
pubmed:publicationType
Journal Article, Research Support, Non-U.S. Gov't