Inhibition of Bacterial and Host-Derived H2S Production for the Therapeutic Enhancement of Anti-Bacterial Host Defense

抽象的。根据CDC的数据，美国每年至少有200万人因 抗药性细菌，每年至少有23,000人因此死亡。某些患者 人群，如手术和创伤患者，特别容易受到机会性感染， 微生物和接受积极的抗生素治疗。新的抗菌疗法的发展- 与现有抗生素联合使用或作为抗生素的替代品-将减少 与多种疾病和感染相关的并发症。这个项目将探索一部小说 通过抑制硫化氢（H2S）的产生来进行抗菌治疗的方法。在过去的十年里， H2S是哺乳动物细胞产生的一种内源性气体递质。最近的研究表明，H2S 也是由细菌产生的重要的是，细菌H2S已被确定为一种新的机制， 细菌体外抗抗生素诱导、氧化剂介导的杀伤作用。细菌是否产生H2S 作为抵抗免疫系统的防御手段尚不清楚。我们的初步数据显示， 宿主或细菌H2S改善体内细菌清除。因此，H2S产生酶可能是 抗菌治疗的新靶点。由于H2S也具有多种生理作用，因此， 了解特定宿主和细菌H2S合成酶在宿主- 病原体相互作用本项目将通过以下具体目标解决这些问题：目标1。到 确定特定的H2S合成酶对介导H2S产生的贡献 感染期间的细菌和宿主反应。组织H2S水平、各种细胞因子的表达和活性 将在感染前和感染期间测量H2S合成酶。H2S合成缺陷小鼠 将酶与野生型小鼠进行比较。野生型与H2S缺陷型细菌菌株的感染 将阐明细菌与宿主来源的H2S的相对贡献。模式和潜在的酶 将鉴定组成性和感染相关H2S水平的调节剂。目标2.为了确定角色， H2S在宿主对感染的易感性和细菌对抗生素治疗的耐药性中的作用。功能 将在两种感染模型中确定特定酶与感染应答的相关性：S.金黄色 肺炎和E.大肠杆菌腹腔败血症。H2S缺陷敲除小鼠将被感染并存活，细菌 将测量清除率、局部和全身炎症、器官功能障碍和免疫细胞活化 并与野生型小鼠进行比较。在感染H2S缺陷型 细菌的菌株。H2S缺陷型细菌和野生型细菌对宿主氧化杀伤的抗性将是 考察最后，抗生素治疗与宿主或细菌H2S缺乏联合使用的疗效将 被评价。该项目将确定细菌或宿主来源的H2S的具体来源， 在未来作为治疗细菌感染的一种全新方法。

Abstract. According to the CDC, at least 2 million people per year in the U.S. develop illness arising from antibiotic-resistant bacteria, and there are at least 23,000 resultant deaths annually. Certain patient populations, such as surgery and trauma patients, are especially susceptible to infections with opportunistic microorganisms and receive aggressive antibiotic therapy. The development of new antibacterial therapies - to be used either in combination with current antibiotics or as an alternative to antibiotics - would reduce complications associated with a wide range of diseases and infections. This project will explore a novel approach to antibacterial therapy through inhibition of hydrogen sulfide (H2S) production. Over the last decade, H2S emerged as an endogenous gasotransmitter produced by mammalian cells. Recent work shows that H2S is also produced by bacteria. Importantly, bacterial H2S has been identified as a novel mechanism that protects the bacteria against antibiotic induced, oxidant-mediated killing in vitro. Whether or not bacteria produce H2S as a defense against the immune system is not known. Our preliminary data show that inhibition of either host or bacterial H2S improves bacterial clearance in vivo. Therefore, H2S-producing enzymes may be novel targets for antibacterial therapy. Since H2S also has multiple physiological roles, it is critical to understand the regulation and relevance of specific host and bacterial H2S-synthesizing enzymes during host- pathogen interactions. This project will address these questions through the following Specific Aims: Aim 1. To identify the contributions of specific H2S-synthesizing enzymes to the production of H2S that mediates bacterial and host responses during infection. Tissue H2S levels, expression and activity of the various H2S-synthesizing enzymes will be measured before and during infection. Mice deficient in H2S-synthesizing enzymes will be compared to wild type mice. Infections with wild type versus H2S-deficient strains of bacteria will elucidate the relative contributions of bacterial- versus host-derived H2S. Patterns and potential enzymatic regulators of constitutive and infection-associated H2S levels will be identified. Aim 2. To determine the roles of H2S in host susceptibility to infection and bacterial resistance to antibiotic therapy. The functional relevance of specific enzymes to infection responses will be determined in two models of infection: S. aureus pneumonia and E. coli abdominal sepsis. H2S-deficient knockout mice will be infected and survival, bacterial clearance, local and systemic inflammation, organ dysfunction, and immune cell activation will be measured and compared to that in WT mice. The same outcomes will be measured after infection with H2S-deficient strains of bacteria. Resistance of H2S-deficient and wild type bacteria to oxidative killing by the host will be examined. Finally, the efficacy of antibiotic treatment in combination with host or bacterial H2S-deficiency will be evaluated. This project will identify specific sources of bacterial or host-derived H2S to be pharmacologically targeted in the future as a fundamentally novel approach to treat bacterial infection.