MECHANISMS OF PROSTAGLANDIN INDUCED INTESTINAL REPAIR

这项研究计划的长期目标是研究机制。 负责肠道屏障的维护和修复。 肠缺血/再灌注损伤的特点是急性 肠道屏障的破坏。然而，初步研究 表明前列腺素发出了显著快速恢复的信号 第二信使Ca~(2+)和Cyclc对上皮屏障的作用 安培。我们的中心假设是前列腺素I2和E2(PGI2和 PGE2)是由环氧合酶-2(COX-2)在肠道中表达的 上皮下层成纤维细胞的损伤和屏障功能的恢复 上皮间紧密连接关闭的信号。紧密连接 作为对细胞内和细胞间协同信号的响应 PGI2刺激的胆碱能神经升高的环磷酸腺苷 和PGE2受体连接的腺苷环化酶。的目标是 这项研究是：确定PGI2和PGE2是否会增加 一种特异性的跨上皮细胞对缺血损伤上皮的抵抗 对紧密连接的作用；以确定神经和上皮 前列腺素I2和前列腺素E_2信号恢复的受体途径 跨上皮阻力；并测定细胞和酶 前列腺素的来源与拯救上皮屏障有关 功能。将使用两种不同的损伤模型：缺血-损伤 肠粘膜和氧化剂损伤的上皮单层。组织 将安装在Ussing小室中，并通过上皮电 耐药性将作为上皮完整性的一个指标进行监测。 放射性标记的通量将被用来确定TREAM的贡献 结合处关闭和恢复。前列腺素的作用机制 信号修复将通过测量第二信使和通过 阻断上皮和神经信号通路。细胞来源 修复性前列腺素的含量将通过免疫组织化学方法确定 成纤维细胞单层研究。COX-2的抑制作用将用于 确定不同环氧合酶在修复中的作用 回应。这些实验将提供对信令的洞察 前列腺素引发心肌梗死修复的途径和机制 急性损伤的肠上皮。

The long range goal of this research program is to study mechanisms responsible for maintenance and restoration of the intestinal barrier. Intestinal ischemia/reperfusion injury is characterized by acute breakdown of the intestinal barrier. However, preliminary studies indicate that prostaglandins signal a remarkably rapid recovery of epithelial barrier function via the second messengers Ca2+ and cyclic AMP. Our central hypothesis is that prostaglandins I2 and E2 (PGI2 and PGE2) are elaborated by cyclooxygenase-2 (COX-2) during intestinal injury from sub-epithelial fibroblasts and restore barrier function by signaling closure of inter-epithelial tight junctions. Tight junctions close in response, to a synergistic signal between intracellular and cyclic AMP, which are increased by PGI2-stimulated cholinergic nerves and PGE2 receptor-linked adenylate cyclase respectively. The aims of this research are: to determine if PGI2 and PGE2 increase transepithelial resistance in ischemic-injured epithelium by a specific action on tight junctions; to determine the neural and epithelial receptor pathways by which PGI2 and PGE2 signal recovery of transepithelial resistance; and to determine the cellular and enzymatic source of prostaglandins responsible for rescuing epithelial barrier function. Two distinct injury models will be used: ischemic-injured intestinal mucosa and oxidant-damaged epithelial monolayers. Tissues will be mounted in Ussing chambers, and transepithelial electrical resistance will be monitored as an indicator of epithelial integrity. Radio-labeled fluxes will be used to determine the contribution of tight junction closure and restitution. Mechanisms by which prostaglandins signal repair will be tested by measuring second messengers and by blocking epithelial and neural signaling pathways. The cellular source of reparative prostaglandins will be determined by immunohistochemistry and fibroblast monolayer studies. Inhibition of COX-2 will be used to determine the contribution of distinct cyclooxygenases in the repair response. These experiments will provide insight into the signaling pathways and mechanisms by which prostaglandins trigger repair of acutely-injured intestinal epithelium.