Macrophage defense againt M. tuberculosis

描述（由申请人提供）：结核病是全球感染导致死亡的主要原因。研究结核分枝杆菌（Mtb）与人巨噬细胞之间的相互作用是了解结核病发病机制的基础。免疫刺激DNA序列及其合成寡核苷酸类似物（CpG-ODN）已被证明在体外和体内具有抗菌作用，我们发现CpG-ODN可激活人单核细胞源性巨噬细胞（hMDM）的抗分枝杆菌活性。这个K08项目的目标是更全面地描述这种CpG-ODN效应的机制和强度。实验将确定抗分枝杆菌反应是否通过TLR9激活，TLR9是唯一已知被CpG-ODN激活的受体。虽然小鼠巨噬细胞可以被干扰素(IFN)- γ激活，在体外杀死细胞内的分枝杆菌，但我们和其他人发现，IFN- γ矛盾地增强了病原体的细胞内生长。人类巨噬细胞限制Mtb的机制尚不清楚，通过描述CpG-ODN激活的机制可能会获得新的知识。我们将确定这种反应是否广泛适用于不同的结核分枝杆菌菌株，以及hMDM与人肺泡巨噬细胞（体内感染结核分枝杆菌的初始宿主细胞）的活性是否存在差异。我们还将测试巨噬细胞样细胞系（THP-1）是否可以用于模拟CpG-ODN反应，因为这些细胞将促进toll依赖信号的分子研究。CpG-ODN效应机制的线索将在巨噬细胞激活和信号传导的功能研究中寻找，并使用微阵列广泛询问受刺激细胞的转录组。最后，我们将通过一组配体比较不同Toll受体的刺激效果，以寻找与CpG-ODN相比的异同，并确定潜在的协同作用。这些研究将为人类巨噬细胞先天抗分枝杆菌功能提供新的基础知识，并为发现新的结核病免疫治疗策略提供合理依据。

DESCRIPTION (provided by applicant): Tuberculosis is a leading cause of death from infection worldwide. Investigations of interactions between Mycobacterium tuberculosis (Mtb) and human macrophages are fundamental for understanding tuberculosis pathogenesis. Immunostimulatory DNA sequences and their synthetic oligonucleotide analogs (CpG-ODN) have been shown to exert antibacterial effects in vitro and in vivo, and we discovered that CpG-ODN activate anti-mycobacterial activity in human monoeyte-derived macrophages (hMDM). The goals of this K08 project are to more fully characterize the mechanism(s) and magnitude of this CpG-ODN effect. Experiments will determine whether anti-mycobacterial responses are activated thorugh TLR9, the only receptor known to be activated by CpG-ODN. While murine macrophages can be activated by interferon (IFN)-gamma to kill intracellular mycobacteria in vitro, we and others have found that IFN-gamma, paradoxically potentiates intracellular growth of the pathogen. The mechanisms whereby human macrophages restrict Mtb remain uncertain, and new knowledge may be gained through delineating the mechanisms acitvated by CpG-ODN. We will determine if this response is broadly applicable to different Mtb strains, and if there are differences between the activity of hMDM and human alveolar macrophages (the initial host cell infected by Mtb in vivo). We will also test whether macrophage-like cell lines (THP-1) can be used to model the CpG-ODN response, since these cells would facilitate molecular studies of Toll-dependent signaling. Clues to the mechanism of this CpG-ODN effect will be sought in functional studies ofmacrophage activation and signaling, and using microarrays to interrogate the transcriptome of stimulated cells broadly. Finally, we will compare the effects of stimulation through different Toll receptors with a panel of ligands to look for similarities or differences compared with CpG-ODN, and to identify potential synergies. These studies will provide new basic knowledge of the innate anti-mycobacterial functions of human macrophages, and they will provide a rational basis for the discovery of new immunotherapeutic strategies for tuberculosis.