cAMP signaling pathways within Mycobacterium tuberculosis

描述（由申请人提供）：结核分枝杆菌（Mtb）是结核病（TB）的病原体，在全球范围内继续对人类健康产生负面影响。该项目的长期目标是了解Mtb在感染期间对其宿主环境的感知和反应方式，以便开发改进的结核病生物标志物和治疗方法。环腺苷酸（cAMP）是由腺苷酸环化酶从ATP产生的，是微生物病原体及其哺乳动物宿主用于感知和响应环境线索的通用第二信使。cAMP通过其与cAMP受体蛋白（CRP）样转录因子的变构相互作用在Mtb和其他细菌病原体中的毒力基因调控中起核心作用。Mtb编码两种这样的转录因子：CrpMt，其在鼠模型中有助于毒力;和Cmr，其调节巨噬细胞内的Mtb基因表达。先前的工作已经表明，在细菌进入巨噬细胞后，Mtb细菌内的cAMP水平急剧增加，这表明cAMP在感知和响应巨噬细胞内环境中的作用。目前的项目解决的假设，cAMP信号有助于结核杆菌宿主相互作用的调节基因表达的细菌内的环境条件。这一假设将在三个具体目标中得到解决。目标1将重新定义CrpMt调节子及其在结核病中的作用 在全球、细胞和分子水平上的感染期间的生物学。目的2：探讨CMR在结核分枝杆菌生物学中的作用，重点是其在巨噬细胞感染和肉芽肿中调节丙酸代谢的作用。目的3提出了CrpMt和Cmr作为与其他转录因子共同调节espA毒力操纵子的作用，使用分子，遗传和细胞方法的组合。这些研究的完成将显著推进对cAMP在结核分枝杆菌生物学中的作用的理解，特别是在细菌感测和对宿主相关条件的响应的背景下。这些信息将有助于确定感染的阶段特异性生物标志物和新的药物靶点。该项目的重要性进一步增强了cAMP在广泛的重要细菌病原体中调节毒力的既定作用，以及Mtb中cAMP相关信号蛋白的异常大和不寻常的网络。

DESCRIPTION (provided by applicant): Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB), continues to negatively impact human health on a global scale. The long term goal of this project is to understand the means by which Mtb senses and responds to its host environment during infection, so that improved biomarkers and treatments for TB disease can be developed. Cyclic AMP (cAMP), which is generated from ATP by adenylyl cyclases, is a universal second messenger used by both microbial pathogens and their mammalian hosts to sense and respond to environmental cues. cAMP plays a central role in virulence gene regulation in Mtb and other bacterial pathogens through its allosteric interactions with cAMP receptor protein (CRP)-like transcription factors. Mtb encodes two such transcription factors: CrpMt, which contributes to virulence in a murine model; and Cmr, which regulates Mtb gene expression within macrophages. Previous work has shown that levels of cAMP within Mtb bacteria increase dramatically upon bacterial entry into macrophages, suggesting a role for cAMP in sensing and responding to the intra-macrophage environment. The current project addresses the hypothesis that cAMP signaling contributes to Mtb-host interactions by regulating gene expression within the bacterium in response to environmental conditions. This hypothesis will be addressed in three specific aims. Aim 1 will redefine the CrpMt regulon and its role in Mtb biology during infection at the global, cellular and molecular levels. Aim 2 addresses the role of Cmr in Mtb biology with a focus on its role in regulating propionate metabolism during macrophage infection and within granulomas. Aim 3 addresses the roles of CrpMt and Cmr as co-regulators with other transcription factors, of the espA virulence operon using a combination of molecular, genetic and cellular approaches. Completion of these studies will significantly advance understanding of cAMP's role in Mtb biology, particularly in the context of bacterial sensing and response to host-associated conditions. This information will contribute to the identification of stage-specific biomarkers of infection and new drug targets. The significance of this project is further enhanced by cAMP's established role in regulating virulence in a wide range of important bacterial pathogens, as well as the exceptionally large and unusual network of cAMP-associated signaling proteins in Mtb.