Highly focused transcriptional response of Anopheles coluzzii to O’nyong nyong arbovirus during the primary midgut infection

Guillaume D Carissimo (1, 2) , Adrien Pain (1, 3) , Eugeni Belda (1, 4) , Kenneth D Vernick (1)

1 Génétique et Génomique des Insectes Vecteurs
2 SIgN - Singapore Immunology Network
3 C3BI - Centre de Bioinformatique, Biostatistique et Biologie Intégrative
4 CHU Pitié-Salpêtrière [AP-HP]

Background: Anopheles mosquitoes are efficient vectors of human malaria, but it is unknown why they do not transmit viruses as well as Aedes and Culex mosquitoes. The only arbovirus known to be consistently transmitted by Anopheles mosquitoes is O'nyong nyong virus (ONNV, genus Alphavirus, family Togaviridae). The interaction of Anopheles mosquitoes with RNA viruses has been relatively unexamined. Results: We transcriptionally profiled the African malaria vector, Anopheles coluzzii, infected with ONNV. Mosquitoes were fed on an infectious bloodmeal and were analyzed by Illumina RNAseq at 3 days post-bloodmeal during the primary virus infection of the midgut epithelium, before systemic dissemination. Virus infection triggers transcriptional regulation of just 30 host candidate genes. Most of the regulated candidate genes are novel, without known function. Of the known genes, a significant cluster includes candidates with predicted involvement in carbohydrate metabolism. Two candidate genes encoding leucine-rich repeat immune (LRIM) factors point to possible involvement of immune protein complexes in the mosquito antiviral response. The primary ONNV infection by bloodmeal shares little transcriptional response in common with ONNV infection by intrathoracic injection, nor with midgut infection by the malaria parasites, Plasmodium falciparum or P. berghei. Profiling of A. coluzzii microRNA (miRNA) identified 118 known miRNAs and 182 potential novel miRNA candidates, with just one miRNA regulated by ONNV infection. This miRNA was not regulated by other previously reported treatments, and may be virus specific. Coexpression analysis of miRNA abundance and messenger RNA expression revealed discrete clusters of genes regulated by Imd and JAK/STAT, immune signaling pathways that are protective against ONNV in the primary infection.

Mots clés: Arbovirus; Insect vectors; Insect immunity; Host – pathogen interactions; Innate immunity; Malaria

Domaines: Sciences du Vivant [q-bio]; Parasitologie; Virologie

Guillaume D Carissimo, Adrien Pain, Eugeni Belda, Kenneth D Vernick. Highly focused transcriptional response of Anopheles coluzzii to O’nyong nyong arbovirus during the primary midgut infection. BMC Genomics, 2018, 19 (1), ⟨10.1186/s12864-018-4918-0⟩. ⟨pasteur-02009990⟩