Pathobiology of Diabetic Gastroenteropathy

糖尿病胃肠病的病理学

• 批准号: 7109154
• 负责人: GIANRICO FARRUGIA
• 金额: $ 32.89万
• 依托单位: MAYO CLINIC ROCHESTER
• 依托单位国家: 美国
• 资助国家: 美国
• 起止时间: 至
• 项目状态: 未结题
• 来源: https://reporter.nih.gov/project-details/7109154
• 关键词: biological signal transduction; carbon monoxide; cell death; cytoprotection; diabetes mellitus; diabetic neuropathy; electrophysiology; enteric nervous system; enzyme activity; enzyme induction /repression; enzyme mechanism; free radical oxygen; gastrointestinal motility /pressure; heme oxygenase; human tissue; immunocytochemistry; intestine disorder; laboratory mouse; molecular biology; nitric oxide; nitric oxide synthase; oxidative stress; pathologic process; stomach disorder; tissue /cell culture

Normal gastrointestinal motility requires maintenance of enteric nerves and the networks of interstitial cells of Cajal (ICC). The overall objective of this proposal is to identify the mechanisms that underlie the pathobiology of diabetic gastroenteropathy (DGE). Our preliminary data suggest a central role for the neuronal nitric oxide synthase/nitric oxide (nNOS/NO) and the heme oxygenase/carbon monoxide (HO/CO) pathways in the maintenance of ICC networks in diabetes. We have made the following key preliminary observations: HO1 is up-regulated in diabetes and serves as a protective mechanism against diabetes-induced oxidative stress. NO up-regulates HO1. Loss of nNOS is an early step in the development of DGE resulting in decrease in NO, loss of up-regulation of HO1 and subsequent decrease in ICC numbers. Supporting the hypothesis that NO is cytoprotective to ICC are preliminary data that show that ICC numbers are decreased in nNOS knockout mice, NOS inhibitors decrease ICC numbers, and NO donors increase ICC numbers in culture. Also, nNOS expression is decreased, HO1 up-regulation is lost and ICC numbers are decreased in patients with DGE. We have also developed animal and human tissue models for DGE and developed a non-invasive test to determine gastric emptying in mice. Based on this work we have generated the novel hypothesis that up-regulation of the HO1/CO pathway by reactive oxygen species serves as an initial cytoprotective mechanism against damage to ICC by AGE and reactive oxygen species. Loss of nNOS expression from enteric nerves leads to loss of continued up-regulation of HO1 resulting in oxidative injury to ICC. Loss of ICC results in loss of the pacemaker signal, failure to amplify neuronal signals and dysmotility. The proposal has two specific aims. In the first aim we will test the hypothesis that DGE results from initial loss of nNOS expression and subsequent loss of ICC. In the second aim we will test the hypothesis that the HO/CO pathway is cytoprotective to ICC and that aberrant regulation of the HO/CO pathway results in decreased ICC and subsequent DGE. The studies will employ newly developed gastric emptying and ICC culture techniques, electrophysiology, immunohistochemistry, and molecular biology to answer the questions raised. We are now uniquely poised to provide new information on the mechanisms that underlie the development of DGE. As this work will identify basic mechanisms that underlie maintenance of ICC it also has implications for further understanding the pathophysioIogy of many of the motility disorders linked to disorders in ICC number and function.

正常的胃肠道运动需要维持肠神经和Cajal（ICC）的间质细胞网络。该提案的总体目的是确定糖尿病性胃病病理生物学（DGE）病理生物学的机制。我们的初步数据表明，神经元一氧化氮合酶/一氧化氮（NNOS/NO）和血红素氧酶/一氧化碳（HO/CO）途径在糖尿病中维持ICC网络中的核心作用。我们进行了以下关键的初步观察：HO1在糖尿病中被上调，并用作防止糖尿病诱导的氧化应激的保护机制。没有上调HO1。 NNOS的损失是DGE发展的早期一步，导致NO下降，HO1上调的损失以及ICC数量随后减少。 支持ICC细胞保护性的假设是初步数据表明，NNOS基因敲除小鼠中ICC的数量减少，NOS抑制剂减少了ICC数量，并且没有供体在培养中增加了ICC数量。同样，nNOS表达降低，HO1上调丢失，DGE患者的ICC数量减少。我们还开发了用于DGE的动物和人体组织模型，并开发了一种非侵入性测试，以确定小鼠的胃排空。基于这项工作，我们产生了一个新的假设，即通过活性氧对HO1/CO途径的上调是一种初始的细胞保护机制，可抵抗年龄和活性氧对ICC损害的损害。 肠神经中NNOS表达的丧失导致HO1的持续上调丧失 导致ICC氧化损伤。 ICC的损失导致起搏器信号的损失，未能 扩增神经元信号和运动障碍。该提案有两个具体的目标。在第一个目的中，我们将检验以下假设：DGE是由NNOS表达的初始丢失和随后的ICC丢失引起的。在第二个目标中，我们将检验以下假设：HO/CO途径对ICC具有细胞保护性，并且对HO/CO途径的异常调节导致ICC降低和随后的DGE。这些研究将采用新开发的胃排空和ICC培养技术，电生理学，免疫组织化学和分子生物学来回答提出的问题。现在，我们有权提供有关DGE发展基础的机制的新信息。由于这项工作将确定ICC维持基础的基本机制，因此它也对进一步理解与ICC数量和功能中疾病相关的许多运动障碍的病理学疾病具有影响。