Genetic dissection of angiogenesis during mycobacterial infection

摘要 结核分枝杆菌每年导致大约150万人死亡。长期 据观察，结核病的中心结构，分枝杆菌肉芽肿， 可以广泛血管化。然而，刺激和功能 这种血管化的后果尚未得到充分的研究。用斑马鱼 分枝杆菌感染模型，概括了人类肉芽肿的重要方面， 我们发现肉芽肿诱导的血管生成与局部 缺氧和经典促血管生成分子Vegfa的转录诱导。 用临床上可用的抑制剂阻断该途径导致负担减轻， 改变免疫反应，改善预后。我们发现一种特殊的环丙烷 细菌脂质海藻糖二霉菌酸酯（TDM）的修饰对肉芽肿至关重要- 诱导血管生成。我们假设这种特定的细菌脂质与 其他分泌的蛋白质驱动或加速血管生成， 分枝杆菌我们将定义致病性的细胞和分子机制， 分枝杆菌促进分枝杆菌肉芽肿的促血管生成环境， 促进自身的成长、传播和生存。我们定义了一个特定的 分枝杆菌肉芽肿内的巨噬细胞对TDM有反应，产生Vegfa， 并诱导血管生成。我们将研究TDM如何驱动NFAT的引入 体内的信号传导途径以及对感染的后果。使用单细胞测序， 我们发现结核性肉芽肿内的上皮样巨噬细胞产生大量 纤连蛋白的量。我们将剖析这种ECM组件的生产如何影响 血管生成和分泌的细菌Ag 85如何与纤连蛋白结合调节血管生成 反应最后，我们将评估ApoA 1轴的细胞自主调节如何在细胞内发挥作用。 感染的巨噬细胞导致血管生成、脂质利用率和免疫功能的变化。 在分枝杆菌感染期间的反应。最终，宿主血管生成的调节 途径可能为结核病的宿主导向疗法提供新的策略。

Abstract Mycobacterium tuberculosis kills approximately 1.5 million people annually. It has long been observed that the central structure of tuberculosis, the mycobacterial granuloma, can be extensively vascularized. However, the inciting stimulus and functional consequences of this vascularization have not been fully examined. Using a zebrafish mycobacterial infection model that recapitulates important aspects of human granulomas, we found that granuloma-induced angiogenesis coincides with the generation of local hypoxia and transcriptional induction of the canonical pro-angiogenic molecule Vegfa. Interception of this pathway with clinically available inhibitors resulted in reduced burden, altered immune responses, and improved outcome. We found that a specific cyclopropane modification on the bacterial lipid trehalose dimycolate (TDM) is critical to granuloma- induced angiogenesis. We hypothesize that this specific bacterial lipid in combination with other secreted proteins drives or accelerates angiogenesis to the benefit of infecting mycobacteria. We will define the cellular and molecular mechanisms by which pathogenic mycobacteria promote the pro-angiogenic environment of mycobacterial granulomas to facilitate their own growth, dissemination and survival. We defined a specific subset of macrophages within the mycobacterial granuloma that respond to TDM, produce Vegfa, and induce angiogenesis. We will examine how TDM drives induction of the NFAT signaling pathway in vivo and the consequences to infection. Using single-cell sequencing, we found that epithelioid macrophages within the tuberculous granuloma produce large amounts of fibronectin. We will dissect how production of this ECM component influences angiogenesis and how secreted bacterial Ag85 binding to fibronectin modulates this response. Finally, we will assess how cell-autonomous regulation of the ApoA1 axis in infected macrophages leads to changes in angiogenesis, lipid availability, and immune response during mycobacterial infection. Ultimately, the modulation of host angiogenic pathways may provide new strategies for host-directed therapies for tuberculosis.