RRC ID 11264
Author Ishii K, Hamamoto H, Kamimura M, Nakamura Y, Noda H, Imamura K, Mita K, Sekimizu K.
Title Insect cytokine paralytic peptide (PP) induces cellular and humoral immune responses in the silkworm Bombyx mori.
Journal J Biol Chem
Abstract In the blood (hemolymph) of the silkworm Bombyx mori, the insect cytokine paralytic peptide (PP) is converted from an inactive precursor to an active form in response to the cell wall components of microorganisms and contributes to silkworm resistance to infection. To investigate the molecular mechanism underlying the up-regulation of host resistance induced by PP, we performed an oligonucleotide microarray analysis on RNA of blood cells (hemocytes) and fat body tissues of silkworm larvae injected with active PP. Expression levels of a large number of immune-related genes increased rapidly within 3 h after injecting active PP, including phagocytosis-related genes such as tetraspanin E, actin A1, and ced-6 in hemocytes, and antimicrobial peptide genes cecropin A and moricin in the fat body. Active PP promoted in vitro and in vivo phagocytosis of Staphyloccocus aureus by the hemocytes. Moreover, active PP induced in vivo phosphorylation of p38 mitogen-activated protein kinase (p38 MAPK) in the fat body. Pretreatment of silkworm larvae with ML3403, a pharmacologic p38 MAPK inhibitor, suppressed the PP-dependent induction of cecropin A and moricin genes in the fat body. Injection of active PP delayed the killing of silkworm larvae by S. aureus, whereas its effect was abolished by preinjection of the p38 MAPK inhibitor, suggesting that p38 MAPK activation is required for PP-dependent defensive responses. These findings suggest that PP acts on multiple tissues in silkworm larvae and acutely activates cellular and humoral immune responses, leading to host protection against infection.
Volume 285(37)
Pages 28635-42
Published 2010-9-10
DOI 10.1074/jbc.M110.138446
PII M110.138446
PMID 20622022
PMC PMC2937889
MeSH Animals Bombyx / immunology* Bombyx / metabolism Cytokines / pharmacology* Gene Expression Profiling Gene Expression Regulation / drug effects Gene Expression Regulation / immunology Hemocytes / immunology* Hemocytes / metabolism Hemolymph / immunology Hemolymph / metabolism Immunity, Cellular / drug effects Immunity, Humoral / drug effects* Immunity, Humoral / immunology Insect Proteins / immunology* Insect Proteins / metabolism Insect Proteins / pharmacology* Larva / immunology Larva / metabolism Neuropeptides / pharmacology* Oligonucleotide Array Sequence Analysis Phagocytosis / drug effects Phagocytosis / immunology Staphylococcus aureus / immunology
IF 4.106
Times Cited 56
Silkworms ?