Prostaglandin E₂ modulates the expression of antimicrobial peptides in the fat body and midgut of Anopheles albimanus

Prostaglandins (PGs) participate in the regulation of vertebrate and in at least six insect orders' immune responses. We identified PGE₂ in midgut, fat body, Malpighian tubules, and ovarioles of Anopheles albimanus (Aa) mosquitoes. Our data indicate that PGE₂ synthesis in cultured midguts responds to the presence of two bacterial species, Micrococcus luteus and Klebsiella pneumoniae. The production of mRNA coding for antimicrobial peptides Aa-Attacin, Aa-Cecropin, and Aa-Gambicin was observed in cultured fat bodies and midguts. The production of these messengers was reduced in the presence of dexamethasone, and this effect was reversed by arachidonic acid. Adding PGE₂ to cultures resulted in increased Aa-cecropin mRNA and decreased Aa-attacin and Aa-gambicin mRNAs. Arch. Insect Biochem. Physiol. 68:14-25, 2008.