Regulators of IFN-gamma responses during Mycobacterium tuberculosis infection

总结 结核病（TB）是全世界传染病导致死亡的主要原因。目前的治疗需要至少六个 目前还没有有效的疫苗来预防肺部疾病。迫切需要 开发新的治疗方法，缩短治疗时间，激活保护性反应，防止结核病进展。 不幸的是，我们仍然缺乏对宿主免疫途径的基本了解， TB.虽然细胞因子干扰素γ（IFNγ）是绝对必需的，但驱动IFNγ介导的 保护措施仍不明确。这是因为IFNγ是一种多效性介质，它控制细菌生长和细胞增殖。 在肺中的炎症反应，同时桥接先天性和适应性免疫反应。解剖 IFNγ应答的复杂调控，我们在巨噬细胞中进行了全基因组CRISPR Cas9筛选， 定义IFNγ介导的MHCII表面表达所需的网络。这个屏幕揭示了一个重要的 甘油3激酶β（GSK 3b）在控制IFNγ依赖性MHCII表达中的作用。使用化学和 遗传学方法与转录组分析相结合，我们发现GSK 3b和parabolic GSK 3a有助于 IFNγ诱导基因的一个子集的表达。进一步的机制研究发现， GSK 3a/B阻断巨噬细胞作为抗原呈递细胞向离体CD 4 + T细胞的能力，结果 在M.肺结核感染。因此，GSK 3a/B平衡了 细胞对IFNγ的应答，以保护免受感染，而不驱动炎性组织损伤。这些数据导致 假设GSK 3a/B是体内TB期间IFNγ应答的关键介体。该提案将使用 结合体内模型的遗传学方法，以剖析GSK 3a/b介导的IFNγ应答控制的作用 还有肺结核目的1将了解调节GSK 3a/B控制IFNγ应答的机制，并确定如何调节IFN γ应答。 M.结核调节GSK 3a/B活性。在目标2中，我们将使用独特的细菌控制和炎症模型 研究骨髓特异性GSK 3a和/或GSK 3b的缺失如何破坏IFNγ介导的M. 结核生长和组织损伤。最后，在目标3中，我们将使用M。结核特异性TCR转基因T细胞 小鼠以检验髓样GSK 3a和/或GSK 3b的缺失导致T细胞应答降低的假设， 对结核病的有效保护。这些目标将共同剖析GSK 3a/B在控制IFNγ应答中的作用 和预防结核病。然后可以利用这些机制来开发新的治疗方法， 治疗时间和预防结核病进展。

Summary Tuberculosis (TB) is a leading cause of death by infectious disease worldwide. Current therapy requires at least six months of treatment and there is no effective vaccine that prevents pulmonary disease. There is a critical need to develop new therapies that will shorten treatment time and activate protective responses to prevent TB progression. Unfortunately, we continue to lack a fundamental understanding of the host immune pathways that protect against TB. While the cytokine interferon γ (IFNγ) is absolutely required, the precise mechanisms that drive IFNγ-mediated protection remain unclear. This is because IFNγ is a pleotropic mediator that controls both bacterial growth and the inflammatory response in the lungs, while bridging the innate and adaptive immune responses. To dissect the complex regulation of IFNγ responses, we conducted a genome-wide CRISPR Cas9 screens in macrophages to define the networks required for the IFNγ-mediated surface expression of MHCII. This screen uncovered an important role for the glycerol 3 kinase beta (GSK3b) in controlling IFNγ-dependent MHCII expression. Using chemical and genetic approaches coupled with transcriptome analysis we found that GSK3b and the paralog GSK3a contribute to the expression of a subset of IFNγ-inducible genes. Further mechanistic studies found that the loss of GSK3a/b blocks the ability of macrophages to serve as antigen presenting cells to CD4+ T cells ex vivo and results in dysregulated cytokine production by macrophages during M. tuberculosis infection. Thus, GSK3a/b balances the cellular response to IFNγ to protect against infection without driving inflammatory tissue damage. These data lead to the hypothesis that GSK3a/b is a critical mediator of the IFNγ response during TB in vivo. This proposal will use genetic approaches combined with in vivo models to dissect the role of GSK3a/b-mediated control of IFNγ responses and TB. Aim 1 will understand the mechanisms that regulate GSK3a/b control of IFNγ responses and determine how M. tuberculosis modulates GSK3a/b activity. In Aim 2, we will use unique models of bacterial control and inflammation to examine how the loss of myeloid-specific GSK3a and/or GSK3b disrupts the IFNγ-mediated control of M. tuberculosis growth and tissue damage. Finally, in Aim 3 we will use M. tuberculosis specific TCR-transgenic T cell mice to test the hypothesis that the loss of myeloid GSK3a and/or GSK3b results in reduced T cell responses and ineffective protection against TB. Together these aims will dissect the role of GSK3a/b in controlling IFNγ-responses and protecting against TB. These mechanisms can then be leveraged to develop new therapies that may shorten treatment times and prevent TB disease progression.