Gut epithelial turnover is altered during midgut maturation, blood feeding and after ingestion of oral pathogens in multiple mosquito species

Mosquito vectors contribute substantially to the world’s burden of infectious disease. Transmissible infections begin in the mosquito midgut, where the gut epithelium acts as a barrier to, and sustains damage from, the invasion of pathogens. The preservation of epithelial integrity during the mosquito life cycle has the potential to determine many key aspects of vector competence, but the process by which the cells of this tissue are maintained and replenished is still unknown. I will present our recent work examining epithelial dynamics (comprising cell loss, cell gain, the proliferation of intestinal stem cells as well as alterations to cell ploidy) in the mosquito midgut of a diverse range of important mosquito vector species including Aedes aegypti, Aedes albopictus, Anopheles gambiae, Anopheles stephensi, and Culex quinquefasciatus. We will focus on basal turnover at homeostasis and on the impact of adult midgut maturation, blood feeding and pathogenic infection on cell dynamics and proliferation. Our observations suggest that the loss of larval enterocytes during the post-eclosion maturation of the adult gut is concomittent with a rapid reconstitution of the midgut epithelium. In addition, our work shows the existence of a specific and variable epithelial response to bloodmeals from different host species and an accelerated epithelial proliferation on all the examined mosquito species and strains upon infection with an oral pathogen.