Ablation of phagocytic hemocytes ameliorates the infection induced changes to the heart physiology of mosquitoes

The circulatory and immune system of mosquitoes are functionally integrated. During an infection, immune cells known as hemocytes aggregate on the heart, and more specifically, at the ostia (valves) where hemolymph flow is highest. These hemocytes, known as periostial hemocytes, produce nitric oxide, which decelerates the frequency of heart contractions and alters the proportional directionality of those contractions. Here, we used liposome chlodronate (a liposome encapsulated ATP synthase inhibitor) to investigate whether the selective ablation of phagocytic hemocytes alters the infection-induced changes to heart physiology. We demonstrate that hemocyte ablation reduces the native population of periostial hemocytes and reduces the number of periostial hemocytes following infection. Moreover, preliminary experiments on the frequency and directionality of heart contractions suggest that hemocyte ablation ameliorates the infection-induced changes to heart physiology. These data provide another layer of evidence that phagocytic hemocytes drive infection-induced changes to the physiology of the mosquito heart.