Linking Human TB Genetic Susceptibility Loci to Granuloma Biology

摘要 结核分枝杆菌每年导致大约140万人死亡。人 暴露于类似的初始剂量可能有非常不同的结果， 到活动性疾病到亚临床或潜伏感染。肺结核的一个中心结构， 肉芽肿代表了病原体和宿主之间的关键界面，其动力学 有助于疾病的结果。肉芽肿巨噬细胞诱导表达一种不寻常的 决定肉芽肿结构和感染轨迹的上皮样程序。由于 缺乏可完全复制肉芽肿关键方面的遗传学上易处理的动物模型 生物学-即上皮样转化和坏死-肉芽肿的许多方面 形成没有被探测。人类全基因组关联研究 确定了几个潜在的结核病易感位点，但这些位点的机制 基因的作用，特别是在肉芽肿中，还没有很好的理解。在这里，我们将链接 建立了人类对分枝杆菌肉芽肿生物学的遗传易感性位点。 我们将使用真正的分枝杆菌肉芽肿的小鼠、斑马鱼和外植体模型 直接探测肉芽肿结构、上皮样状态、免疫和药物通路， 肉芽肿动力学。使用单细胞转录谱和宿主和细菌 突变体，我们已经定义了不同细胞类型和转录状态的库， 有助于分枝杆菌肉芽肿的生理特性。我们将定义 在全基因组人类遗传学研究中如何确定宿主免疫途径的改变 通过小鼠和斑马鱼模型改变肉芽肿生物学， 人类肉芽肿的性质，包括干酪样坏死和上皮样 转型我们将在人类结核肉芽肿标本中验证这些发现。最后， 我们将使用饱和的Mtb转座子文库来进行全面的TnSeq分析， 定义结核病背景下细菌和宿主之间的相互作用， 肉芽肿总的来说，这些方法将导致更全面的了解肉芽肿 生物学以及治疗干预的新机会。

Abstract Mycobacterium tuberculosis kills approximately 1.4 million people annually. People exposed to similar initial doses may have very different outcomes, ranging from clearance to active disease to subclinical or latent infection. A central structure of tuberculosis, the granuloma represents a key interface between pathogen and host, and its dynamics contribute to disease outcome. Granuloma macrophages induce expression of an unusual epithelioid program that dictates granuloma structure and infection trajectory. Due to a lack of genetically tractable animal models that fully reproduce key aspects of granuloma biology – namely, epithelioid transformation and necrosis – many aspects of granuloma formation have not been probed. Genome-wide association studies in humans have identified several potential TB susceptibility loci, but the mechanisms by which these genes act, particularly within the granuloma, are not well understood. Here we will link established human genetic susceptibility loci to the biology of mycobacterial granulomas. We will use murine, zebrafish, and explant models of bona fide mycobacterial granulomas to directly probe granuloma structure, epithelioid state, immune and drug access and granuloma dynamics. Using single cell transcriptional profiling and host and bacterial mutants, we have defined a repertoire of diverse cell types and transcriptional states that contribute to the physiological properties of the mycobacterial granuloma. We will define how alteration of host immune pathways identified in genome-wide human genetic studies alter granuloma biology through murine and zebrafish models that recapitulate key properties of human granulomas, including caseation necrosis and epithelioid transformation. We will validate these findings in human TB granuloma specimens. Finally, we will use comprehensive TnSeq profiling using saturating Mtb transposon libraries to define the interplay between bacteria and host within the context of the tuberculous granuloma. Overall, these approaches will lead to a fuller understanding of granuloma biology as well as new opportunities for therapeutic interventions.