Mechanisms of adverse host responses to antibiotics

描述(申请人提供)：最近发生的生物恐怖主义事件和新出现的传染病在全球的迅速传播揭示了开发有效和安全的疗法的迫切需要，这种疗法可以很容易地应用于美国典型的大规模和基因多样化的人口。在对2001年炭疽菌生物恐怖袭击的全面审查中，对“长期使用抗菌剂的依从性、依从性障碍和不良事件”的调查被认为是一个高度优先的研究领域。这项研究的目的是阐明宿主对用于治疗NIAID优先病原体的抗菌剂的不良反应的分子机制。这项建议侧重于氟喹诺酮类药物，特别是环丙沙星，这是用于炭疽暴露后预防的主要抗生素，也是治疗其他NIAID优先病原体的一种选择。氟喹诺酮类药物的副作用导致肠粘连，最常见的是胃肠道。在这项建议中要探索的新假设是，许多这些不良副作用是由肝脏和/或胃肠道中形成的反应性氟喹诺酮代谢物引起的。氟喹诺酮类药物在人体内的主要代谢产物是酰基葡萄糖醛酸苷，它们与生物分子形成共价加合物的潜力很大。在初步研究中，我们发现了环丙沙星和曲伐沙星葡萄糖醛酸苷的自发降解和酰基迁移的证据，类似于观察到的非甾体抗炎药的葡萄糖醛酸苷。与R21研究项目的探索性相一致，本提案的具体目标如下。首先，我们将使用原代人肝细胞和人肠道细胞株来量化3种经常与人体胃肠道副作用相关的氟喹诺酮类药物(曲伐沙星、格列帕沙星和司帕沙星)与3种与这些副作用不太相关的氟喹诺酮类药物(环丙沙星、氧氟沙星和诺氟沙星)的细胞毒性。其次，我们将确定抑制可能导致反应性代谢物形成的酶(UGT、CYP和酰基辅酶A连接酶)是否将这些药物的体外毒性降至最低。随着这些研究的完成，我们将对可能导致氟喹诺酮类药物临床重要副作用的生化途径有了更深入的了解。在未来的工作中，我们将通过体内研究来验证这些发现，并确定可能导致副作用易感性个体差异的宿主遗传因素。我们的最终目标是在需要对大量遗传多样性人群进行长期治疗的情况下，通过药物遗传学方法优化这些药物的更广泛的临床应用。

DESCRIPTION (PROVIDED BY APPLICANT): Recent events of bioterrorism and the rapid global spread of emerging infectious diseases has revealed a compelling need to develop effective and safe therapeutics that can be readily applied to large and genetically diverse populations, typical of the United States. In a comprehensive review of the 2001 anthrax bioterrorist attack, investigation of "adherence, barriers to adherence, and adverse events associated with long-term use of antimicrobial agents" was considered to be a high priority research area. The objective of this research is to elucidate molecular mechanisms underlying adverse host responses to antimicrobial agents used to treat NIAID Priority Pathogens. This proposal focuses on the fluoroquinolones, particularly ciprofloxacin, which was the primary antibiotic used for anthrax post-exposure prophylaxis, and is an option for treatment of other NIAID Priority Pathogens. Side effects of the fluoroquinolones leading to nonadherence most commonly involve the gastrointestinal (GI) tract. The novel hypothesis to be explored in this proposal is that many of these adverse side effects result from the formation of reactive fluoroquinolone metabolites in the liver and/or GI tract. Major metabolites of the fluoroquinolones in humans are acyl glucuronides, which have a high potential for covalent adduct formation with biomolecules. In preliminary studies, we show evidence for spontaneous degradation and acyl migration of ciprofloxacin and trovafloxacin glucuronides similar to that observed with glucuronides of the nonsteroidal anti-inflammatory drugs. Consistent with the exploratory nature of an R21 Research Project, the specific aims of this proposal are as follows. Firstly, we will use primary human hepatocytes and human intestinal cell lines to quantify the Cytotoxicity of 3 fluoroquinolones frequently associated with adverse GI side effects in people (trovafloxacin, grepafloxacin and sparfloxacin) compared with 3 fluoroquinolones less commonly associated with these side effects (ciprofloxacin, ofloxacin, and norfloxacin) . Secondly, we will determine whether inhibition of enzymes potentially responsible for reactive metabolite formation (UGT, CYP and acyl CoA ligase) minimizes the in vitro toxicity of these drugs. By the completion of these studies we will have developed an understanding of the biochemical pathways potentially responsible for clinically important adverse side effects of the fluoroquinolones. In future work we will verify these findings through in vivo studies and identify host genetic factors that may account for individual variability in side effect susceptibility. Our ultimate goal is to optimize the broader clinical application of these drugs through a pharmacogenetic approach in situations where long-term treatment of large and genetically diverse populations is necessitated.