VhaAC39-1 regulates gut homeostasis and affects the health span in Drosophila.

Gut homeostasis is a dynamically balanced state to maintain intestinal health. Vacuolar ATPases (V-ATPases) are multi-subunit proton pumps that were driven by ATP hydrolysis. Several subunits of V-ATPases may be involved in the maintenance of intestinal pH and gut homeostasis in Drosophila. However, the specific role of each subunit in this process remains to be elucidated. Here, we knocked down the Drosophila gene VhaAC39-1 encoding the V0d1 subunit of V-ATPases to assess its function in gut homeostasis. Knockdown of VhaAC39-1 resulted in the loss of midgut acidity, the increase of the number of gut microbiota and the impairment of intestinal epithelial integrity in flies. The knockdown of VhaAC39-1 led to the hyperproliferation of intestinal stem cells, increasing the number of enteroendocrine cells, and activated IMD signaling pathway and JAK-STAT signaling pathway, inducing intestinal immune response of Drosophila. In addition, knockdown of VhaAC39-1 caused the disturbance of many physiological indicators such as food intake, triglyceride level and fecundity of flies, which ultimately led to the shortening of the life span of Drosophila. These results shed light on the gut homeostasis mechanisms which would help to identify interventions to promote healthy aging.