Neshat S, deVries M, Barajas-Espinosa A R, Skeith L, Chisholm S P, Lomax A E
Department of Physiology, Queen's University, Kingston, Ontario, Canada.
Am J Physiol Gastrointest Liver Physiol. 2009 Feb;296(2):G399-405. doi: 10.1152/ajpgi.90450.2008. Epub 2008 Dec 12.
Evidence from patients with inflammatory bowel disease (IBD) and animal models suggests that inflammation alters blood flow to the mucosa, which precipitates mucosal barrier dysfunction. Impaired purinergic sympathetic regulation of submucosal arterioles, the resistance vessels of the splanchnic vasculature, is one of the defects identified during IBD and in mouse models of IBD. We hypothesized that this may be a consequence of upregulated catabolism of ATP during colitis. In vivo and in vitro video microscopy techniques were employed to measure the effects of purinergic agonists and inhibitors of CD39, an enzyme responsible for extracellular ATP catabolism, on the diameter of colonic submucosal arterioles from control mice and mice with dextran sodium sulfate [DSS, 5% (wt/vol)] colitis. Using a luciferase-based ATP assay, we examined the degradation of ATP and utilized real-time PCR, Western blotting, and immunohistochemistry to examine the expression and localization of CD39 during colitis. Arterioles from mice with DSS colitis did not constrict in response to ATP (10 microM) but did constrict in the presence of its nonhydrolyzable analog alpha,beta-methylene ATP (1 microM). alpha,beta-Methylene ADP (100 microM), an inhibitor of CD39, restored ATP-induced vasoconstriction in arterioles from mice with DSS-induced colitis. CD39 protein and mRNA expression was markedly increased during colitis. Immunohistochemical analysis demonstrated that, in addition to vascular CD39, F4/80-immunoreactive macrophages accounted for a large proportion of submucosal CD39 staining during colitis. These data implicate upregulation of CD39 in impaired sympathetic regulation of gastrointestinal blood flow during colitis.
来自炎症性肠病（IBD）患者和动物模型的证据表明，炎症会改变流向黏膜的血流，从而导致黏膜屏障功能障碍。嘌呤能交感神经对黏膜下小动脉（内脏血管系统的阻力血管）的调节受损是在IBD患者和IBD小鼠模型中发现的缺陷之一。我们推测这可能是结肠炎期间ATP分解代谢上调的结果。采用体内和体外视频显微镜技术，测量嘌呤能激动剂和CD39（一种负责细胞外ATP分解代谢的酶）抑制剂对对照小鼠和葡聚糖硫酸钠[DSS，5%（重量/体积）]结肠炎小鼠结肠黏膜下小动脉直径的影响。使用基于荧光素酶的ATP检测方法，我们检测了ATP的降解情况，并利用实时PCR、蛋白质印迹和免疫组织化学方法检测了结肠炎期间CD39的表达和定位。患有DSS结肠炎的小鼠的小动脉对ATP（10微摩尔）无收缩反应，但在其不可水解类似物α，β-亚甲基ATP（1微摩尔）存在时会收缩。α，β-亚甲基ADP（100微摩尔），一种CD39抑制剂，恢复了DSS诱导的结肠炎小鼠小动脉中ATP诱导的血管收缩。在结肠炎期间，CD39蛋白和mRNA表达显著增加。免疫组织化学分析表明，除了血管CD39外，F4/80免疫反应性巨噬细胞在结肠炎期间占黏膜下CD39染色的很大比例。这些数据表明，CD39上调与结肠炎期间胃肠道血流交感神经调节受损有关。
