title: CpG-containing oligodeoxynucleotides increases resistance of Anopheles mosquitoes to Plasmodium infection.
abstract: Unmethylated CpG dinucleotide motifs in bacterial DNA or in synthetic oligodeoxynucleotides (ODN) are potent stimulators of the vertebrate innate immune system. However, the potential of these DNA species to modulate mosquito immunity have not been explored. In the present study, we investigated the effects of CpG-ODN on the outcome of Plasmodium infection in insects and on the modulation of mosquito immunity to Plasmodium. Anopheles stephensi and Anopheles gambiae mosquitoes inoculated with CpG-ODN showed significant reductions in the prevalence of Plasmodium infection, intensity of Plasmodium infection, and number of eggs produced. Microarrays were used to elucidate the transcriptional profiles of the fat bodies of CpG-ODN-treated mosquitoes. In total, 172 genes were differentially expressed, of which 136 were up-regulated and 36 were down-regulated. The major functional class of CpG-ODN-regulated genes encoded immune response-related proteins (31%). Within this group, genes associated with coagulation/wound healing were the most frequently represented (23%). Knockdown of a transglutaminase gene that was up-regulated by the CpG-ODN and chemical inhibition of the enzyme resulted in a significant increase in Plasmodium infection. Mosquitoes that were treated with CpG-ODNs were found to be less susceptible to Plasmodium infection. Transcriptional profiling of the fat body suggests that protection is associated with coagulation/wound healing. We show for the first time that transglutaminase activity plays a role in the control of Plasmodium infection.
authors.affiliation: Centro de Malária e Outras Doenças Tropicais, UEI Parasitologia Médica, Instituto de Higiene e Medicina Tropical, Universidade Nova de Lisboa, Rua da Junqueira, 100, 1349-008 Lisboa, Portugal. hsilveira@ihmt.unl.pt
authors.forename: Henrique
authors.initials: H
authors.lastname: Silveira
authors.forename: Ana
authors.initials: A
authors.lastname: Gabriel
authors.forename: Susana
authors.initials: S
authors.lastname: Ramos
authors.forename: Joel
authors.initials: J
authors.lastname: Palma
authors.forename: Rute
authors.initials: R
authors.lastname: Felix
authors.forename: Ana
authors.initials: A
authors.lastname: Custódio
authors.forename: L Vincent
authors.initials: LV
authors.lastname: Collins
mesh_terms: D000818:Animals; D000852:Anopheles / Q000187:drug effects* / Q000235:genetics / Q000276:immunology* / Q000469:parasitology; D005786:Gene Expression Regulation / Q000187:drug effects; D007109:Immunity / Q000187:drug effects; D019476:Insect Proteins / Q000235:genetics / Q000276:immunology; D009838:Oligodeoxyribonucleotides / Q000494:pharmacology*; D010961:Plasmodium / Q000502:physiology; D011503:Transglutaminases / Q000235:genetics / Q000276:immunology
chemical_list: C408982:CPG-oligonucleotide; D019476:Insect Proteins; D009838:Oligodeoxyribonucleotides; D011503:Transglutaminases