Mycobacterial Sulfation Pathways

项目描述（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鸟分枝杆菌与艾滋病的致命协同作用方面。结核分枝杆菌和鸟分枝杆菌多重耐药菌株的出现进一步增加了对新的治疗途径的需求。结核分枝杆菌感染是一个复杂的过程，涉及驻留在肺巨噬细胞内，刺激免疫反应和形成肉芽肿，进入潜伏期，并最终从潜伏期出现产生活动性结核。病原体和宿主之间需要复杂的相互作用来维持生命周期的各个阶段。这个项目是由我们在分枝杆菌基因组中发现假定的硫转移酶和磺化酶而发起的。在分枝杆菌中发现了少量硫酸代谢物，包括丰富的细胞壁糖脂-磺酸脂-1 (SL-1)，但其功能尚不清楚。在真核生物中，已知硫酸盐代谢物在细胞间通讯中起作用。因此，我们推测分枝杆菌中的硫酸盐代谢物可能参与了宿主-病原体的相互作用。上一次批准期集中在三个具体目标上：1)确定分枝杆菌硫转移酶的功能；2)研究分枝杆菌硫酸酯酶的功能；3)明确结核分枝杆菌硫同化途径。在下一个授权期内，我们计划继续研究硫酸分枝杆菌的代谢机制。我们将研究硫酸代谢物和相关的生物合成酶在结核分枝杆菌和鸟分枝杆菌中的生物学作用（目的1）。我们将在基于细胞的实验和免疫受损小鼠中研究结核分枝杆菌磺化突变体，以评估其与适应性和先天免疫机制的相互作用（目的2）。将寻求APS还原酶的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磺化酶（Aim 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).