Dép de microbiologie-infectiologie et d'immunologie, fac de médecine, Université Laval, Quebec City, QC, Canada.
Axe Maladies infectieuses et immunitaires, CHU de Québec - Université Laval, Quebec City, QC, Canada.
Gut. 2022 Jan;71(1):43-54. doi: 10.1136/gutjnl-2020-320937. Epub 2021 Jan 15.
Nucleotides are danger signals that activate inflammatory responses via binding P2 receptors. The nucleoside triphosphate diphosphohydrolase-8 (NTPDase8) is an ectonucleotidase that hydrolyses P2 receptor ligands. We investigated the role of NTPDase8 in intestinal inflammation.
We generated NTPDase8-deficient () mice to define the role of NTPDase8 in the dextran sodium sulfate (DSS) colitis model. To assess inflammation, colons were collected and analysed by histopathology, reverse transcriptase-quantitative real-time PCR (RT-qPCR) and immunohistochemistry. P2 receptor expression was analysed by RT-qPCR on primary intestinal epithelium and NTPDase8 activity by histochemistry. The role of intestinal P2Y receptors was assessed by bone marrow transplantation experiments and with a P2Y receptor antagonist.
NTPDase8 is the dominant enzyme responsible for the hydrolysis of nucleotides in the lumen of the colon. Compared with wild-type (WT) control mice, the colon of mice treated with DSS displayed significantly more histological damage, immune cell infiltration, apoptosis and increased expression of several proinflammatory cytokines. P2Y was the dominant P2Y receptor expressed at the mRNA level by the colonic epithelia. Irradiated mice transplanted with WT bone marrow were fully protected from DSS-induced intestinal inflammation. In agreement, the daily intrarectal injection of a P2Y antagonist protected mice from DSS-induced intestinal inflammation in a dose-dependent manner. Finally, human intestinal epithelial cells express NTPDase8 and P2Y similarly as in mice.
NTPDase8 protects the intestine from inflammation most probably by limiting the activation of P2Y receptors in colonic epithelial cells. This may provide a novel therapeutic strategy for the treatment of inflammatory bowel disease.
核苷酸是通过与 P2 受体结合而激活炎症反应的危险信号。核苷三磷酸二磷酸水解酶-8（NTPDase8）是一种外核苷酸酶，可水解 P2 受体配体。我们研究了 NTPDase8 在肠道炎症中的作用。
我们生成了 NTPDase8 缺陷型（）小鼠，以确定 NTPDase8 在葡聚糖硫酸钠（DSS）结肠炎模型中的作用。为了评估炎症，收集结肠并通过组织病理学、逆转录定量实时 PCR（RT-qPCR）和免疫组织化学进行分析。通过 RT-qPCR 分析原发性肠道上皮细胞和 NTPDase8 活性的 P2 受体表达。通过骨髓移植实验和 P2Y 受体拮抗剂评估肠道 P2Y 受体的作用。
NTPDase8 是负责结肠腔中核苷酸水解的主要酶。与野生型（WT）对照小鼠相比，用 DSS 处理的 小鼠的结肠显示出明显更多的组织损伤、免疫细胞浸润、细胞凋亡和几种促炎细胞因子的表达增加。P2Y 是结肠上皮细胞中表达水平最高的 P2Y 受体。用 WT 骨髓照射的 小鼠进行骨髓移植可完全防止 DSS 诱导的肠道炎症。同样，每天直肠内注射 P2Y 拮抗剂可剂量依赖性地保护小鼠免受 DSS 诱导的肠道炎症。最后，人肠道上皮细胞表达 NTPDase8 和 P2Y 与小鼠相似。
NTPDase8 通过限制 P2Y 受体在结肠上皮细胞中的激活来保护肠道免受炎症。这可能为治疗炎症性肠病提供一种新的治疗策略。
