Genetic dissection of angiogenesis during mycobacterial infection

摘要 结核分枝杆菌每年导致约150万人死亡。它已经有很长时间了 已经观察到结核的中心结构，分枝杆菌肉芽肿， 可以广泛地血管化。然而，煽动性刺激和功能性 这种血管化的后果还没有得到充分的研究。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血管生成是一致的。 低氧和典型的促血管生成分子Vegfa的转录诱导。 用临床上可用的抑制剂阻断这一途径导致了负担的减轻， 改变了免疫反应，改善了结果。我们发现一种特殊的环丙烷 细菌脂类海藻糖二羟甲酸酯(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类与 其他分泌蛋白驱动或加速血管生成，从而有利于感染 分枝杆菌。我们将定义致病的细胞和分子机制 分枝杆菌促进分枝杆菌肉芽肿促血管生成环境 促进自身的成长、传播和生存。我们定义了特定的子集 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如何推动NFAT的诱导 体内信号通路及其对感染的影响。使用单细胞测序， 我们发现结核肉芽肿内的上皮样巨噬细胞产生大的 纤维连接蛋白的含量。我们将剖析这种ECM组件的生产如何影响 血管生成及其与纤维连接蛋白结合的分泌细菌Ag85如何调节血管生成 回应。最后，我们将评估细胞自主调节载脂蛋白A1轴在 感染的巨噬细胞导致血管生成、脂质可获得性和免疫功能的改变 在分枝杆菌感染期间的反应。最终，宿主血管生成的调节 途径可能为宿主导向的结核病治疗提供新的策略。

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.