Cellular stress response to the oxidizing effects of bleach

描述（由申请人提供）：次氯酸（HOCl）是家用漂白剂的活性成分，在先天免疫反应中起强大的抗菌作用。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和应对漂白剂知之甚少。据我们所知，迄今为止还没有在任何生物体中发现对hocl敏感的转录调节因子。我们实验室的初步结果表明，保守的NemR蛋白是大肠杆菌中hocl特异性转录抑制因子。我们有证据表明，HOCl氧化导致NemR中形成特定的分子间二硫键，从而调节转录活性并诱导耐漂白剂所需基因的表达。我将使用体外生化方法和体内遗传技术来检查NemR在细菌漂白剂抗性中的作用。我将通过分析保守半胱氨酸残基在NemR中的作用以及在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。

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.