Cellular stress response to the oxidizing effects of bleach

描述(申请人提供)：次氯酸(HOCl)，家用漂白剂的活性成分，在天然免疫反应中作为一种强大的抗菌剂发挥作用。尽管漂白剂被广泛使用，但令人惊讶的是，人们对细菌如何感知漂白剂并对其做出反应知之甚少。据我们所知，到目前为止，还没有在任何生物体中发现对HOCl敏感的转录调控因子。我们实验室的初步结果表明，在大肠杆菌中，保守的NemR蛋白是HOCl特异的转录抑制因子。我们有证据表明，HOCl的氧化导致NEMR中特定的分子间二硫键的形成，这些二硫键调节转录活性并诱导耐漂白所需基因的表达。我将使用体外生化方法和体内基因技术来研究NEMR在细菌漂白耐药性中所起的作用。我将通过分析保守的半胱氨酸残基在NEMR中的作用以及HOCl-处理后NEMR的结构和功能变化来研究HOCl感知的机制。这项研究的结果将对我们理解细胞如何感知HOCl和修复细胞损伤具有潜在的广泛意义。过量的HOCl-产生与许多人类疾病的进展有关，包括慢性炎症、动脉粥样硬化和癌症，以及细菌与人类免疫系统的相互作用。 与公共健康相关：本申请中提出的项目将提供有关细菌如何感知和应对漂白剂中活性抗菌成分次氯酸的氧化应激影响的见解。这项工作关系到人类健康，不仅因为漂白剂是一种常用的消毒剂，还因为次氯酸是免疫系统的白细胞产生的一种重要的抗菌化合物。

DESCRIPTION (provided by applicant): Hypochlorous acid (HOCl), the active component of household bleach, functions as a powerful antimicrobial during the innate immune response. Despite its widespread use, surprisingly little is known about how bacteria sense and respond to bleach. To our knowledge, no HOCl-sensitive transcriptional regulator has been identified in any organism to date. Preliminary results from our lab implicate the conserved NemR protein as an HOCl-specific transcriptional repressor in E. coli. We have evidence that oxidation by HOCl causes the formation of specific intermolecular disulfide bonds in NemR, which modulate transcriptional activity and induce the expression of genes required for bleach tolerance. I will use both in vitro biochemical approaches and in vivo genetic techniques to examine the role that NemR plays in bacterial bleach resistance. I will investigate the mechanism of HOCl sensing by analyzing the role of conserved cysteine residues in NemR and the structural and functional changes in NemR that occur upon HOCl-treatment. The results of this study will have potentially broad implications on our understanding of how cells sense HOCl and repair cellular damage. Excessive HOCl-production is implicated in the progression of many human diseases, including chronic inflammation, atherosclerosis and cancer and in bacterial interactions with the human immune system. PUBLIC HEALTH RELEVANCE: The project proposed in this application will provide insights into how bacteria sense and respond to the oxidative stress effects of hypochlorous acid, the active antimicrobial component of bleach. This work is relevant to human health not only because bleach is a commonly used disinfectant, but also because hypochlorous acid is an important antimicrobial compound produced by the white blood cells of the immune system.