Mechanisms of H pylori-Induced Hypochlorhydria

幽门螺杆菌引起胃酸过少的机制

• 批准号: 7190041
• 负责人: ADAM J SMOLKA
• 金额: $ 25.5万
• 依托单位: MEDICAL UNIVERSITY OF SOUTH CAROLINA
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-03-15 至 2009-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7190041
• 关键词: 5' Flanking Region; Acids; Acute; Acute Clinical Course; Agonist; Ammonium; Anatomic Sites; Antral; Archives; Atrophic Gastritis; Biological Assay; Biopsy; Body of uterus; Cell Count; Cells; Chimera organism; Chronic; Classification; Clinical; DNA-Protein Interaction; Data; Deletion Mutation; Down-Regulation; Dysplasia; Epithelial Cells; Functional disorder; Gastric Adenocarcinoma; Gastric Parietal Cells; Gastric mucosa; Gastrins; Gastritis; Gel; Gene Expression; Generations; Genes; Genetic Transcription; Genotype; Gland; Goals; H(+)-K(+)-Exchanging ATPase; Helicobacter; Helicobacter Infections; Helicobacter pylori; Human; Hypochlorhydria; Immunochemistry; Immunohistochemistry; In Vitro; Infection; Inflammatory Response; Ingestion; Intestinal Metaplasia; Ions; Measures; Messenger RNA; Modeling; Molecular; Patients; Phase; Proteins; Proton Pump; Pylorus; Range; Regulation; Regulatory Element; Reporter; Reverse Transcriptase Polymerase Chain Reaction; Solid; Stomach; Techniques; Testing; Time; Transcriptional Regulation; Transfection; Translations; Urease; Virulence; base; deletion analysis; innovation; mutant; promoter; response; transcription factor

DESCRIPTION (provided by applicant): The goal of this study is to define the molecular mechanisms underlying the hypochlorhydria associated with Helicobacter pylori-induced gastritis. Clinical and in vitro evidence associates gastric corpus H. pylori infection with acid hyposecretion and generation of an inflammatory response. In a significant subset of patients, the ensuing gastritis progresses to atrophic gastritis, intestinal metaplasia, dysplasia, and eventually gastric adenocarcinoma. This study tests the hypothesis that acute H. pylori infection down-regulates H,K-ATPase (proton pump) gene expression by perturbing normal interactions of cis-regulatory elements on the HKalpha gene promoter and cellular trans-activating proteins, thereby inhibiting parietal cell acid secretion. In preliminary studies, exogenous H,K-ATPase alpha subunit (HKalpha) promoter sequences transiently transfected into human gastric adenocarcinoma (AGS) cells were responsive to acid secretory agonists and antagonists, and were inhibited by H. pylori infection. This approach forms the experimental basis for three Specific Aims: 1) To identify in gastric epithelial cells H. pylori-responsive c/s-regulatory elements and cognate transcription factors involved in regulation of HK( gene transcription; 2) To investigate the mechanisms whereby specific H. pylori genotypes induce down-regulation of HKalpha gene transcription; and 3) To investigate HKalpha subunit gene transcription and translation within H. pylori.infected and uninfected human gastric mucosa. Basal and H. pylori-responsive cis-regulatory elements and transactivating proteins in transfected ACTS cells will be investigated by deletion analysis, electrophoretic mobility shift, supershift, and solid-phase protein/DNA interaction assays. Acid-inhibitory H. pylori genotypes will be identified by assessing HKa promoter activity in transfected ACTS cells infected with H. pylori mutant strains deficient in virulence-associated genes. Finally, gastric H,K-ATPase mRNA levels and proton pump expression, as measured by real-time RT-PCR and quantitative immunochemistry in a large, well documented archive of human gastric biopsies, will be investigated in the context of intragastric pH, infection status, H. pylori strain identity, and anatomic site of infection. These studies will establish the mechanistic basis of H. pylori-induced gastric hypochlorhydria, and add to the understanding of H. pylori pathophysiology.

描述（由申请人提供）：这项研究的目的是定义与幽门螺杆菌诱导的胃炎相关的次氯甘蓝的分子机制。临床和体外证据将胃肠菌感染与酸性降低和炎症反应的产生相关联。在大部分患者中，随后的胃炎发展为萎缩性胃炎，肠道化生，发育不良以及最终的胃腺癌。这项研究检验了以下假设：急性幽门螺杆菌感染通过扰动hkalpha基因启动子和细胞跨激活蛋白的顺式调节元件的正常相互作用，从而下调H，K-ATPase（Proton Pump）基因表达，从而抑制了Parietal Cell Acid Acid Acid Acid酸的分泌。在初步研究中，外源H，K-ATPase Alpha亚基（Hkalpha）启动子序列暂时转染到人胃中 腺癌（AGS）细胞对酸性分泌激动剂和拮抗剂有反应，并被幽门螺杆菌感染抑制。这种方法构成了三个特定目的的实验基础：1）在胃上皮细胞中识别幽门螺杆菌反应的C/S调节元件和与HK调节调节有关的转录因子（基因转录; 2），以调查幽门螺杆菌下降的特定特定的H.幽门螺杆菌的机制。 3）研究幽门螺杆菌中的hkalpha亚基基因转录和翻译。感染和未感染的人类胃粘膜。将通过缺失分析，电泳迁移率转移，Supershift和固相蛋白/DNA相互作用分析来研究基础和幽门螺杆菌反应的顺式调节元件和转染作用细胞中的反式激活蛋白。通过评估被毒力相关基因缺乏幽门螺杆菌突变菌株感染的转染活性细胞中的HKA启动子在感染的转染的ACTS细胞中，将鉴定幽门螺杆菌基因型。最后，通过实时RT-PCR和定量的免疫化学测量胃H，K-ATPase mRNA水平和质子泵的表达，在大型，有记录的人类胃活检档案中，将在胃内pH，感染状态，H。Pylori菌株菌株鉴定和解剖部位的胃内。 这些研究将建立幽门螺杆菌诱导的胃次氯氢化氢的机械基础，并增加对幽门螺杆菌病理生理学的理解。