Role of Tuberculosinyl Metabolites in M. Tuberculosis Virulence

 描述(申请人提供)：结核杆菌代谢物在结核杆菌毒力中的作用摘要在所有类型的分枝杆菌中，结核分枝杆菌是世界上最流行和最致命的病原体。为了找到使其致病的特定分子，我们将结核分枝杆菌中所有可检测到的脂质与非致病疫苗株(BCG)中的那些进行了比较。这一消减筛选鉴定了一种以前称为结节素腺苷(TbAd)的分子以及产生它的基因(Rv3377c，Rv3378c)。尽管TbAd在一个世纪的结核病研究中被忽视，但我们的初步数据表明，TbAd是最丰富的脂类之一，由六个结构相关的亚家族产生。公布的数据显示，结核分枝杆菌在分枝杆菌中是独一无二的，因为它能够在受感染的巨噬细胞的吞噬小体中生存，这是因为它阻止了酸介导的巨噬细胞的细菌杀伤。我们的初步数据显示，TbAd足以阻断巨噬细胞吞噬小体的酸化。因此，我们推测TbAd和相关的结核蛋白代谢物是长期寻找的影响结核分枝杆菌逃脱细胞内死亡的独特能力的分子。在这里，我们建议在结核分枝杆菌中发现新的结核代谢物并确定它们的自然结构。利用合成的TbAd和人类巨噬细胞，我们将确定TbAd选择性抑制吞噬小体酸化的细胞机制，同时仍允许结核分枝杆菌进入其吞噬小体的生态位。利用缺乏生物合成酶的结核分枝杆菌(Rv3378c，Rv3377c)，我们将测量TbAd在自然感染结局中的影响。最后，我们将测试结核代谢物作为新的人类结核病诊断测试的目标。几个特征表明，TbAd和TbAd特异性抗体可能是一种高度特异的化学标志物或感染。结核分枝杆菌大量分泌TbAd，但缺乏其他类似结核病的病原体。因此，我们将在利马、秘鲁和小鼠中检测血清和尿液中的TbAd和TbAd特异性抗体。

 DESCRIPTION (provided by applicant): Role of tuberculosinyl metabolites in M. tuberculosis virulence Abstract Among all types of mycobacteria, Mycobacterium tuberculosis is the world's most prevalent and deadly pathogen. To find the particular molecules that enable its pathogenicity, we compared all detectable lipids in M. tuberculosis to those in a non-pathogenic vaccine strain (BCG). This subtractive screen identified a previously type of molecule called tuberculosinyl adenosine (TbAd) as well as the genes (Rv3377c, Rv3378c) that produce it. Although TbAd was overlooked in a century of tuberculosis research, our preliminary data show that TbAd is one of the most abundant lipids and is produced as six structurally related subfamilies. Published data show that M. tuberculosis is unique among mycobacteria in its ability to survive within the phagosomes of infected macrophages, based in its blockade of acid-mediated bacterial killing by macrophages. Our preliminary data show that TbAd is sufficient to block acidification of macrophage phagosomes. Therefore, we posit that TbAd and related tuberculosinyl metabolites are the long sought molecules that influence M. tuberculosis' unique ability to escape intracellular death. Here we propose to discover new tuberculosinyl metabolites in M. tuberculosis and determine their natural structures. Using synthetic TbAd and human macrophages, we will determine the cellular mechanism by which TbAd selectively inhibits phagosome acidification, while still allowing M. tuberculosis to be taken up into its phagosomal niche. Using M. tuberculosis lacking the biosynthetic enzymes (Rv 3378c, Rv3377c), we will measure the influence of TbAd in the outcome of natural infections. Last, we will test tuberculosinyl metabolites as targets for new diagnostic tests for human tuberculosis. Several features suggest that TbAd and TbAd-specific antibodies could be a highly specific chemical marker or infection. TbAd is abundantly secreted by M. tuberculosis, but is lacking in other pathogens that mimic tuberculosis. Therefore, we will detect TbAd and TbAd specific antibodies in serum and urine from a well-characterized patient cohort in Lima, Peru and in mice.