The ATP-hydrolyzing ectoenzyme E-NTPD8 attenuates colonic inflammation through regulation of P2X4 receptor-dependent metabolism in myeloid cells [F1413]. The ATP-hydrolyzing ectoenzyme E-NTPD8 attenuates colonic inflammation through regulation of P2X4 receptor-dependent metabolism in myeloid cells [F1413]

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 the ATP signaling leads to disruption of mucosal immune system linked to pathogenesis of intestinal inflammation. In the small intestine, hydrolysis of luminal ATP by E-NTPD7 in epithelial cells is essential for control of the number of Th17 cells. However, the molecular mechanism underlying regulation of microbiota-derived ATP in the colon is poorly understood. Here, we show that E-NTPD8 is highly expressed in large intestinal epithelial cells and hydrolyzes microbiota-derived luminal ATP. Compared to wild-type mice, Entpd8-/- mice develop more severe DSS-induced colitis. In this context, either depletion of neutrophils and monocytes by injecting with anti-Gr-1 antibody or introduction of P2rx4 deficiency into hematopoietic cells ameliorates colitis in Entpd8-/- mice. Increased level of luminal ATP in the colon of Entpd8-/- mice promotes glycolysis in neutrophils and monocytes through P2X4 receptor-dependent Ca2+ influx, which links to prolonged survival and elevated ROS production in these cells. Together, these results indicate that E-NTPD8 limits intestinal inflammation by controlling metabolic alteration toward glycolysis via P2X4 receptor in myeloid cells. Overall design: We analyzed Gr-1+ CD11b+ cells with RNA-seq analysis.

细胞外三磷酸腺苷（Extracellular adenosine triphosphate, ATP）由黏膜免疫细胞与肠腔微生物群释放，可触发多样免疫应答以维持肠道稳态，该过程依赖P2嘌呤能受体（P2 purinergic receptors）；而ATP信号的过度激活则会破坏黏膜免疫系统，与肠道炎症的发病机制密切相关。
在小肠中，上皮细胞表达的E-NTPD7可水解肠腔ATP，这对调控Th17细胞的数量至关重要。然而，目前对于结肠中微生物群来源ATP的调控分子机制仍不甚明晰。
本研究发现，E-NTPD8在大肠上皮细胞中高表达，并可水解微生物群来源的肠腔ATP。与野生型小鼠相比，Entpd8-/-小鼠会出现更为严重的葡聚糖硫酸钠（DSS）诱导的结肠炎。
在此模型中，通过注射抗Gr-1抗体清除中性粒细胞与单核细胞，或是在造血细胞中引入P2rx4基因缺陷，均可减轻Entpd8-/-小鼠的结肠炎症状。
Entpd8-/-小鼠结肠肠腔的ATP水平升高，可通过P2X4受体依赖的钙离子内流，促进中性粒细胞与单核细胞的糖酵解过程，进而延长这些细胞的存活时间并增强其活性氧（reactive oxygen species, ROS）的产生。
综上，上述结果表明，E-NTPD8可通过调控髓系细胞中P2X4受体介导的糖酵解代谢重编程，从而限制肠道炎症的发生发展。
实验整体设计：我们通过RNA测序（RNA-seq）分析了Gr-1+ CD11b+细胞。