Acid Adaptation Targets for Eradication of Helicobacter pylori

根除幽门螺杆菌的酸适应目标

• 批准号: 8041113
• 负责人: George Sachs
• 金额: --
• 依托单位: VA GREATER LOS ANGELES HEALTHCARE SYSTEM
• 依托单位国家: 美国
• 财政年份: 2010
• 资助国家: 美国
• 起止时间: 2010-10-01 至 2014-09-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8041113
• 关键词: Acclimatization; Acidity; Acids; Amino Acids; Ammonia; Amoxicillin; Antibiotic Resistance; Antibiotics; Aspartate; Bacteria; Bacterial Infections; Bicarbonates; Binding; Buffers; Carbon Dioxide; Clarithromycin; Complex; Development; Down-Regulation; Drops; Enabling Factors; Ensure; Environment; Failure; Food; Gases; Gastric Juice; Gastric mucosa; Gene Cluster; Gene Targeting; Genes; Genetic Transcription; Gerbils; Glutamates; Grant; Growth; H(+)-K(+)-Exchanging ATPase; Healed; Helicobacter Infections; Helicobacter pylori; Histidine; Homology Modeling; Human; In Vitro; Infection; Investigation; Japan; Lead; Life Style; Maintenance; Measures; Medicine; Membrane; Methods; Metronidazole; Morbidity - disease rate; Mutation; Nature; Nutrient; Omeprazole; Organism; Outcome; Pathway interactions; Peptic Ulcer; Permeability; Pharmaceutical Preparations; Phase; Population; Process; Property; Protein Biosynthesis; Proteins; Regulation; Regulon; Relative (related person); Research; Resistance; Risk; Risk Factors; Role; Signal Transduction; Site; Site-Directed Mutagenesis; Small RNA; Stimulus; Stomach; Surface; System; Therapeutic; Time; Transcriptional Activation; Ulcer; United States; Up-Regulation; Urea; Urease; Veterans; base; carbonate dehydratase; cell growth; combat; drug development; extracellular; falls; healing; high risk; improved; in vivo; inhibitor/antagonist; malignant stomach neoplasm; membrane assembly; mortality; novel; pH Homeostasis; pathogen; periplasm; porin; prevent; promoter; protein-histidine kinase; protonation; response; sensor; success

DESCRIPTION (provided by applicant): Helicobacter pylori infects the stomach of half of the world's population. This infection is a primary cause of peptic ulcer disease and a high risk factor for gastric cancer. Therefore, eradication of this H. pylori infection leads to ulcer healing and lowers the risk of gastric cancer. Until the discovery of H. pylori, it was thought that stomach acid presented an inhospitable environment for bacterial infection. However, H. pylori has uniquely developed the means of surviving and growing on the acidic surface of the human stomach, a process termed acid acclimation. Disruption of this process leads to loss of survival in acid, therefore the components of this process would provide novel targets for eradication therapy. Current eradication therapies require the use of antibiotics along with acid inhibitory drugs. The successful eradication by these therapies is decreasing due to increasing antibiotic resistance, resulting in a response rate of < 80% in the USA. Acid acclimation is the ability of the organism to maintain a neutral periplasmic pH homeostasis in the presence of acid to allow gastric infection. Bacteria sense and respond to environmental stimuli via two component histidine kinase signaling systems. In the case of H. pylori, environmental acidification sensing is initiated through the HP0165/HP0166 two component system. Accordingly, the first hypothesis to be explored is that graded responses to acidity are regulated by this HP0165/HP0166 two component system. The system responds by acid-induced transcriptional upregulation of two promoters in the urease gene cluster, pureA and pureI, acid-induced post-translational upregulation of assembly UreI with apourease and the urease accessory proteins required for Ni2+ insertion along with Ni2+ entry, and also post-transcriptional down regulation by sRNAs at neutral pH. The UreI/urease membrane assembly is essential for acid acclimation and acid survival of the organism, and an understanding of the assembly mechanism is required for targeted therapy to this process. Therefore, the role of the HP0165/HP0166 TCS in membrane recruitment, assembly and activation of urease, in regulation of sRNA control of urease expression, and pH sensing by the TCS will be explored. The growth dependent antibiotics clarithromycin or amoxicillin are not effective unless bacteria are in growth phase. Improving acid inhibition should improve therapeutic outcome. In the second aim, we hypothesize that inhibition of acid secretion increases the number of bacteria in growth phase, making them sensitive to growth dependent antibiotics necessitating the requirement for administration of acid inhibitory compounds, in addition to antibiotics for successful eradication. The finding that slow omeprazole metabolizers respond with much improved acid control and effective eradication with omeprazole and amoxicillin alone, suggests that improved acid inhibition increases the sensitivity of the organism to growth dependent antibiotics. From this it follows that, with more consistent and greater elevation of intragastric pH, more organisms are in the antibiotic sensitive growth phase rather than the resistant stationary phase. Maintenance of an elevated pH for both day and night should put almost all H. pylori in growth phase. Therefore, the effect of acid inhibition on the rate of H. pylori protein synthesis as an indicator of bacterial cell growth will be measured in vitro and in vivo. PUBLIC HEALTH RELEVANCE: H. pylori infection has a causal role in peptic ulcer disease and increases the risk of gastric cancer. Peptic ulcer disease and gastric cancer are major causes of morbidity in the Veterans population, in the United States and worldwide. H. pylori inhabits the stomach and has evolved unique acid response mechanisms to allow gastric colonization. Standard triple or quadruple therapies with acid blocking medicines and antibiotics have become less effective, falling below 80% success rate due to increasing antibiotic resistance. An understanding of how H. pylori colonizes the stomach will aid the development of novel eradication therapies. A possible strategy to replace current therapy is to target genes that allow the bacteria to survive in acid with non-antibiotic compounds. Another possible strategy is to improve control of the pH of the bacterial environment, so that dual therapy with acid inhibition and amoxicillin could be used. This would involve development of drugs with better acid blocking properties.

描述（由申请人提供）： 幽门螺杆菌感染了世界上一半人口的胃。这种感染是消化性溃疡疾病的主要原因，也是胃癌的高危因素。因此，根除H.幽门螺杆菌感染可导致溃疡愈合，并降低患胃癌的风险。直到H.幽门螺杆菌，人们认为胃酸为细菌感染提供了一个不适宜的环境。然而，H.幽门螺杆菌已经独特地发展出在人胃的酸性表面上存活和生长的方式，这一过程被称为酸适应。这一过程的破坏导致在酸中存活的丧失，因此这一过程的组分将为根除治疗提供新的靶点。目前的根除疗法需要使用抗生素沿着酸抑制药物。由于抗生素耐药性的增加，这些疗法的成功根除率正在下降，导致美国的缓解率< 80%。 酸适应是生物体在酸存在下维持中性周质pH稳态以允许胃感染的能力。细菌通过双组分组氨酸激酶信号系统感知和响应环境刺激。在H. pylori，通过HP 0165/HP 0166双组分系统启动环境酸化感测。因此，要探讨的第一个假设是，酸度的分级响应是由这个HP 0165/HP 0166双组分系统调节的。该系统通过酸诱导的尿素酶基因簇中的两个启动子pureA和pureI的转录上调，酸诱导的装配UreI与尿素酶和Ni 2+插入沿着Ni 2+进入所需的尿素酶辅助蛋白的翻译后上调，以及中性pH下sRNA的转录后下调。摘要脲酶膜组装对于生物体的酸适应和酸存活是必不可少的，并且理解组装机制对于针对该过程的靶向治疗是必需的。因此，将探索HP 0165/HP 0166 TCS在脲酶的膜募集、组装和活化中的作用，在脲酶表达的sRNA控制的调节中的作用，以及TCS的pH传感。 生长依赖性抗生素克拉霉素或阿莫西林是无效的，除非细菌处于生长期。改善酸抑制应改善治疗结果。在第二个目标中，我们假设酸分泌的抑制增加了生长期细菌的数量，使它们对生长依赖性抗生素敏感，除了抗生素外，还需要施用酸抑制化合物以成功根除。奥美拉唑代谢缓慢者对奥美拉唑和阿莫西林单独给药的酸控制和有效根除反应大大改善，这一发现表明，酸抑制的改善增加了生物体对生长依赖性抗生素的敏感性。由此可见，随着胃内pH值的更一致和更大的升高，更多的微生物处于抗生素敏感生长期，而不是耐药稳定期。昼夜保持pH值升高应使几乎所有的H. pylori生长期因此，酸抑制对H.将在体外和体内测量作为细菌细胞生长指示剂的幽门螺杆菌蛋白质合成。 公共卫生相关性： H.幽门螺杆菌感染与消化性溃疡有关，并会增加患胃癌的机会。消化性溃疡疾病和胃癌是美国和世界范围内退伍军人人群发病的主要原因。H.幽门螺杆菌存在于胃中，并且已经进化出独特的酸反应机制以允许胃定植。标准的三重或四重疗法与酸阻断药物和抗生素已经变得不那么有效，由于抗生素耐药性的增加，成功率下降到80%以下。了解H。将有助于开发新的根除疗法。一个可能的策略，以取代目前的治疗是靶向基因，使细菌生存在酸与非抗生素化合物。另一种可能的策略是改善对细菌环境pH的控制，从而可以使用酸抑制和阿莫西林的双重治疗。这将涉及开发具有更好酸阻断特性的药物。