The Gastric Biology of Helicobacter Pylori

描述（由申请人提供）：目的是研究胃病原体幽门螺杆菌的胃生理学。具体目标：（A）。鉴定细胞质pH传感器的酸响应调节子和信号系统。在pH 2.5孵育后使用转录组分析，将鉴定HP 0244、HP 0703独立的调节子以将周质（HP 0165）与细胞质pH调节分开，并通过qPCR确认;（B）通过比较H.幽门螺杆菌感染的沙鼠与酸抑制和不抑制。H. pylori感染沙鼠胃与体外培养的H. pylori中编码参与酸适应的蛋白质的基因的上调比在体外pH 4.5时更大，可能反映了定殖生物体的生态位中的pH <4.5。细胞分裂、壁和蛋白质合成基因也增加。初步数据显示，PPI的酸抑制作用将前一组的表达降低到体外pH 4.5时的水平，但增加了后三组生长相关基因的表达，这可能解释了PPI与生长依赖性抗生素联合用于三联疗法的必要性。这些数据可能导致长效PPI +阿莫西林的双重治疗;（C）研究pH诱导的尿素酶复合物和其他蛋白质活化和运输到内膜上的UreI，并确定这是否受HP 0165或HP 0244的调节。幽门螺杆菌（约占总蛋白质的10%）是胃感染所必需的。在中性条件下，只有1/3的脲酶有活性，2/3的酶是无活性的脱辅基酶。脱辅基酶的pH依赖性活化将提供比从头合成更快的对酸的响应。初步结果表明，有激活和转运的脲酶在酸性pH值，这是依赖于HP 0165。UreI作为膜的锚，使脲酶依赖pH重新定位到内膜，这是激活脱尿素酶所必需的。这项研究可能为改善根除治疗提供新的线索，从而降低消化性溃疡疾病和胃癌的风险。 公共卫生相关性：幽门螺杆菌是导致消化性溃疡和胃癌风险增加40倍的原因。我们将分析H.通过研究胃pH调节基因的信号系统以及尿素酶运输和激活在感染中的作用，酸抑制对H.幽门螺杆菌可能会改善或替代三联疗法根除。

DESCRIPTION (provided by applicant): The aims are to investigate the gastric physiology of the gastric pathogen Helicobacter pylori. Specific Aims: (A). Identify the acid response regulon and signaling system of the cytoplasmic pH sensor. HP0244 is a previously unsuspected sensor of cytoplasmic pH. Using transcriptome analysis after pH 2.5 incubation, the HP0244, HP0703 independent, regulon will be identified to separate periplasmic (HP0165) from cytoplasmic pH) regulation and confirmed by qPCR; (B) Identify colonization dependent gene expression and evaluate pH control of their expression by comparative transcriptome analysis of H. pylori from infected gerbils with and without acid suppression. Transcriptome analysis of H. pylori infecting the gerbil stomach compared to in vitro cultured H. pylori showed a greater up-regulation of genes encoding proteins involved in acid acclimation than at pH 4.5 in vitro, likely reflecting a pH <4.5 in the niche of the colonizing organisms. Cell division, wall and protein biosynthesis genes were also increased. Preliminary data show that acid inhibition by a PPI reduces expression of the former group to the level found at pH 4.5 in vitro but augments expression of the latter three groups of growth-related genes, this may explain the need for a combination of a PPI with growth-dependent antibiotics for triple therapy. These data may lead to dual therapy with a long acting PPI + amoxicillin; (C) Investigate pH-induced activation and trafficking of a urease complex and other proteins to UreI on the inner membrane and determine whether this is regulated by HP0165 or HP0244 The expression of urease by H. pylori (~10% of total protein) is essential for gastric infections. However, at neutral pH, only 1/3rd of urease is active, 2/3rd is present as inactive apoenzyme. pH-dependent activation of the apoenzyme would provide a more rapid response to acid than de novo synthesis. Preliminary results suggest that there is activation and translocation of urease at acidic pH that is dependent on HP0165. UreI serves as the membrane anchor for the pH- dependent relocation of urease to the inner membrane and this is required for activation of apourease. This research may provide new leads for improvement eradication therapy thereby decreasing the risk of peptic ulcer disease and gastric cancer. PUBLIC HEALTH RELEVANCE: Helicobacter pylori is responsible for peptic ulcers and a fortyfold increased risk of gastric cancer. We shall analyze the physiology of H. pylori in the stomach by investigating signaling systems for genes regulated by gastric pH and the role of urease trafficking and activation in infection. A better understanding of effects of acid inhibition on H. pylori may allow improvement or replacement of triple therapy for eradication.