The midgut transcriptome of Aedes aegypti fed with saline or protein meals containing chikungunya virus reveals genes potentially involved in viral midgut escape

This study seeks to understand the mechanism of midgut escape and identify candidate genes and potential biochemical pathways involved in the midgut infection of chikungunya virus (CHIKV) in vector mosquito Aedes aegypti. We conducted a comparative transcriptomic analysis of midgut samples of female mosquitoes,after feeding a saline meal (SM) or a protein meal (PM) containing CHIKV. Our results allow the conclusion that midgut-expressed genes not involved in blood or protein digestion can be identified by substituting either a bloodmeal or PM for a SM. In presence of orally acquired CHIKV in midguts of SM fed mosquitoes, the majority of the upregulated DE genes belonged to the categories immune system and catalytic activity. These genes included several serine-type endopeptidases, trypsins, collagenases, and M1 zinc metalloproteases, which potentially could be involved in the midgut escape mechanism of CHIKV. One of the serine metalloproteinase genes, AeLT, was further analyzed showing strong (MMP) collagenase activity in vitro. Our results present a set of candidate genes potentially responsible for overcoming the arbovirus midgut escape barrier (MEB) in Ae. aegypti. Overall design: We used genome-wide transcriptome analyses of midguts to reveal gene expression patterns in midguts of protein meal and saline meal (containing/not containing CHIKV) fed mosquitoes in comparison to a sugarfed control.

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Dong S, Behura SK, Franz AWE