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Plasmatocyte‐spreading peptide influences hemocyte behavior via eicosanoids
Author(s) -
Srikanth Koigoora,
Park Junga,
Stanley David W.,
Kim Yonggyun
Publication year - 2011
Publication title -
archives of insect biochemistry and physiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.576
H-Index - 66
eISSN - 1520-6327
pISSN - 0739-4462
DOI - 10.1002/arch.20450
Subject(s) - biology , biosynthesis , spodoptera , gene silencing , microbiology and biotechnology , arachidonic acid , signal transduction , exigua , eicosanoid , fmrfamide , npr1 , immune system , receptor , biochemistry , gene , immunology , enzyme , neuropeptide , medicine , natriuretic peptide , recombinant dna , heart failure
Hemocyte‐spreading behavior is required for expressing a cellular immune response, nodulation, which clears the vast majority of invading microbes from circulation. The nodulation response is completed by a layer of plasmatocytes, which spread over the nodule and initiate a malanization process leading to darkened nodules. Plasmatocyte‐spreading peptide (PSP), the first reported insect cytokine, is responsible for mediating the spreading and attachment of some subclasses of plasmatocytes to nodules. Prostaglandins (PGs), one group of eicosanoids formed from arachidonic acid (AA), also mediate plasmatocyte spreading (PS), although the potential interactions between the PSP and PG signal transduction pathways have not been investigated. We tested our hypothesis that PSP acts via biosynthesis of eicosanoids, specifically PGs, in the beet armyworm, Spodoptera exigua . In this study, we report that (1) PSP and PGE 2 independently stimulated Ca ++ ‐dependent PS, (2) inhibitors of PG biosynthesis reversibly blocked PS, (3) dsRNA silencing the gene encoding proPSP blocked PS, which was rescued by PSP and by AA, (4) PSP‐stimulated PS was reversibly impaired by inhibitors of PG biosynthesis, and (5) the inhibitor‐impaired spreading was rescued by AA. Taken together, these points strongly support our model showing that PSP acts via a plasmatocyte‐surface receptor, which stimulates biosynthesis of the PGs responsible for mediating plasmatocytes spreading. © 2011 Wiley Periodicals, Inc.