The ATP-hydrolyzing ectoenzyme E-NTPD8 attenuates colitis through modulation of P2X4 receptor–dependent metabolism in myeloid cells

Abstract

Significance Intestinal bacteria produce extracellular ATP in the lumen during their growth, which drives host immune responses. To avoid excessive immune reactions in the intestinal mucosa, luminal ATP is finely tuned. However, how the concentration of luminal ATP is controlled in the colon remains poorly understood. Here, we discovered that ATP-hydrolyzing enzyme E-NTPD8 acts as an immunomodulator in the colon. Entpd8 deficiency led to high sensitivity to DSS-induced colitis in mice, which was due to the sustained survival of colonic neutrophils. Extracellular ATP suppressed apoptosis by inducing metabolic alteration toward glycolysis via P2X4R in neutrophils. These results reveal the mechanism preventing innate intestinal pathology through modulation of myeloid cell metabolism and may serve to identify therapeutic targets for IBD. Extracellular adenosine triphosphate (ATP) released by mucosal immune cells and by microbiota in the intestinal lumen elicits diverse immune responses that mediate the intestinal homeostasis via P2 purinergic receptors, while overactivation of ATP signaling leads to mucosal immune system disruption, which leads to pathogenesis of intestinal inflammation. In the small intestine, hydrolysis of luminal ATP by ectonucleoside triphosphate diphosphohydrolase (E-NTPD)7 in epithelial cells is essential for control of the number of T helper 17 (Th17) cells. However, the molecular mechanism by which microbiota-derived ATP in the colon is regulated remains poorly understood. Here, we show that E-NTPD8 is highly expressed in large-intestinal epithelial cells and hydrolyzes microbiota-derived luminal ATP. Compared with wild-type mice, Entpd8−/− mice develop more severe dextran sodium sulfate–induced colitis, which can be ameliorated by either the depletion of neutrophils and monocytes by injecting with anti–Gr-1 antibody or the introduction of P2rx4 deficiency into hematopoietic cells. An increased level of luminal ATP in the colon of Entpd8−/− mice promotes glycolysis in neutrophils through P2x4 receptor–dependent Ca2+ influx, which is linked to prolonged survival and elevated reactive oxygen species production in these cells. Thus, E-NTPD8 limits intestinal inflammation by controlling metabolic alteration toward glycolysis via the P2X4 receptor in myeloid cells.