Mycobacterial Sulfation Pathways

描述(由申请人提供)：该项目的长期目标是研究硫酸盐和含硫代谢物在结核分枝杆菌(M.TB)生命周期和发病机制中的作用。分枝杆菌病原体已被世界卫生组织宣布为全球紧急情况，特别是在结核分枝杆菌和禽分枝杆菌与艾滋病的致命协同作用方面。结核分枝杆菌和禽类分枝杆菌多药耐药菌株的出现进一步加剧了对新治疗途径的需求。结核分枝杆菌感染是一个复杂的过程，包括滞留在肺巨噬细胞内，刺激免疫反应和形成肉芽肿，进入潜伏期，最终从潜伏期出现，产生活动性结核病。病原体与寄主之间的复杂相互作用需要维持生命周期的不同阶段。这个项目是由我们在分枝杆菌基因组中发现的假定的硫基转移酶和硫酸盐酶发起的。在分枝杆菌中已鉴定出几种硫酸盐代谢物，包括丰富的细胞壁糖脂-1(SL-1)，但它们的功能尚不清楚。在真核生物中，已知的硫酸代谢物在细胞间的通讯中发挥作用。因此，我们推测分枝杆菌中的硫酸代谢物可能参与宿主与病原体的相互作用。最后一个授权期集中在三个具体目标上：1)确定分枝杆菌硫酸盐转移酶的功能；2)调查分枝杆菌硫酸盐酶的功能；3)确定结核分枝杆菌的硫同化途径。在下一个授权期内，我们计划继续研究硫酸盐分枝杆菌的代谢机制。我们将研究硫酸盐代谢物和相关的生物合成酶在结核分枝杆菌和禽分枝杆菌中的生物学作用(目标1)。我们将在基于细胞的试验和免疫受损的小鼠中研究结核分枝杆菌硫酸盐化突变，以评估与适应性和先天免疫机制的相互作用(目标2)。将寻找APS还原酶小分子抑制剂作为功能研究的工具和药物开发的先导(目标3)。最后，我们将进一步表征分枝杆菌甲酰甘氨酸生成酶和硫酸酯酶(目标4)。

DESCRIPTION (provided by applicant): The long-term objective of this project is to study the roles of sulfated and sulfur-containing metabolites in the life cycle and pathogenesis of Mycobacterium tuberculosis (M. tb). Mycobacterial pathogens have been declared a global emergency by the World Health Organization, particularly in regard to the deadly synergy of M. tb and M. avium with AIDS. The emergence of multidrug resistant strains of both M. tb and M. avium has further escalated the need for new therapeutic avenues. M. tb infection is a complex process that involves residence within lung macrophages, stimulation of an immune response and the formation of granulomas, entry into a latent phase and, ultimately, emergence from latency to produce active tuberculosis. Complex interactions between the pathogen and its host are required to sustain the various stages of the life cycle. This project was initiated by our discovery of putative sulfotransferases and sulfatases in mycobacterial genomes. A handful of sulfated metabolites had been identified in mycobacteria, including the abundant cell wall glycolipid sulfolipid-1 (SL-1), but their functions were unknown. In eukaryotes, sulfated metabolites are known to play roles in cell-cell communication. We therefore speculated that the sulfated metabolites in mycobacteria may be involved in host-pathogen interactions. The last granting period focused on three Specific Aims: 1) define the functions of mycobacterial sulfotransferases; 2) investigate the functions of mycobacterial sulfatases; and 3) define the sulfur assimilation pathway in Mycobacterium tuberculosis. In the next granting period we plan to continue our studies of the mycobacterial sulfate metabolic machinery. We will investigate the biological roles of sulfated metabolites and the associated biosynthetic enzymes in both M. tb and M. avium (Aim 1). We will study M. tb sulfation mutants in cell-based assays and immune-compromised mice in order to assess interactions with adaptive and innate immune mechanisms (Aim 2). Small molecule inhibitors of APS reductase will be sought as tools for functional studies and leads for drug development (Aim 3). Finally, we will further characterize mycobacterial formylglycine generating enzymes and sulfatases (Aim 4).