Autophagy Against Tuberculosis and HIV

描述(由申请人提供)： 结核病(TB)和获得性免疫缺陷综合征(AIDS)是对公共卫生具有特殊意义的疾病。它们的重要性因全球结核病和艾滋病的共同流行而进一步增强。结核分枝杆菌(Mtb)和人类免疫缺陷病毒(HIV)与各自的病原体共同感染，改变了由每种病原体单独引起的疾病的进程。通常，在没有艾滋病毒的情况下，只有10%的结核分枝杆菌感染进展为临床活动性结核病。取而代之的是，建立了一种可控的、持久的无症状感染，称为潜伏结核病感染(LTBI)。LTBI的建立和 进展为活动性疾病的驱动因素尚不完全清楚。要推动这一领域向前发展，需要采取以前从未尝试过的方法。在这项应用中，我们将采取一种新的方法，展示自噬在维持长期结核病感染和进展为活动性结核病之间的平衡方面的关键作用，以及作为艾滋病毒-结核分枝杆菌联合感染期间病毒靶向的过程。自噬是一种新发现的但仍在进化的古老的先天免疫机制，它作为一种细胞自主防御包括结核分枝杆菌在内的各种细胞内病原体。我们发表的工作和其他人的研究表明，当适当地诱导时，自噬是一种重要的抗结核分枝杆菌细胞自主先天免疫防御。我们认为，自噬可以防止进展为活动性疾病，有利于LTBI。这种宿主保护作用是基于自噬的两个效应器功能：第一，它消除细胞内的Mtb，第二，它抑制致病细胞因子反应。在这个项目中，我们将检验这样一个假设，即自噬维持宿主保护状态并防止进展为活动性结核病，而内在宿主因素或HIV合并感染干扰自噬并促进临床显性结核病。如果这一假设是正确的，该项目中确定的针对自噬和特定过程的药理学靶向将提供新的预防和治疗机会。这项应用的具体目的是：特定目的1.确定HIV是否以及如何干扰混合感染的巨噬细胞中结核分枝杆菌的自噬消除。从机制上，我们将确定HIV临床分离株中HIV蛋白Nef及其等位基因的作用，并测试它们抑制Beclin 1依赖的自噬和抑制巨噬细胞中Mtb消除的能力。具体目标2.确定自噬是否以及如何抑制I型干扰素(干扰素)反应，与进展为活动性疾病有关。我们将测试自噬是否阻止与活动性结核病相关的I型干扰素的诱导，以及这如何影响结核病的发病机制。明确细胞中性脂质负荷是否以及如何影响结核分枝杆菌的自噬控制。为了确定固有的宿主因素(在没有HIV的情况下)如何影响自噬维持宿主保护状态的能力--即。LTBI状态-我们将测试宿主细胞脂质储存和细胞脂质负荷失衡是否影响结核分枝杆菌的自噬控制。

DESCRIPTION (provided by applicant): Tuberculosis (TB) and acquired immunodeficiency syndrome (AIDS) are diseases of exceptional public health significance. Their importance is further heightened by the global TB-AIDS co-pandemic. A co-infection with the respective etiologic agents, Mycobacterium tuberculosis (Mtb) and human immunodeficiency virus (HIV) alters the course of diseases caused by each infectious agent alone. Typically, only 10% of Mtb infections progress to clinically active TB in the absence of HIV. Instead, a controlled, long lasting asymptomatic infection, referred to as latent TB infection (LTBI), is established. Establishment of LTBI and the drivers of progression to active disease are not fully understood. Previously untried approaches are needed to move the field forward. In this application, we will take a new approach by demonstrating the key role of autophagy in maintaining the balance between LTBI and progression to active TB, and as a process targeted by the virus during HIV-Mtb co-infection. Autophagy is a newly recognized but nevertheless evolutionary ancient innate immunity mechanism that acts as a cell-autonomous defense against a variety of intracellular pathogens including Mtb. Our published work and studies by others indicate that autophagy, when appropriately induced, is a significant anti-Mtb cell- autonomous innate immunity defense. We propose that autophagy prevents progression to active disease and favors LTBI. The host-protective action is based on two effector functions of autophagy: first, it eliminates intracellulr Mtb, and, second, it suppresses pathogenic cytokine responses. In this project, we will test the hypothesis that autophagy maintains a host-protective state and prevents progression to active TB, whereas intrinsic host factors or HIV co-infection interfere with autophagy and promote clinically overt TB. If this hypothesis is correct, pharmacological targeting of autophagy and specific processes identified in this project will provide new prophylactic and treatment opportunities. The specific aims of this application are: Specific Aim 1. Determine whether and how HIV interferes with autophagic elimination of Mtb in co- infected macrophages. Mechanistically, we will define the role of the HIV protein Nef and its alleles from clinical HIV isolates and test their capacity to inhibit Beclin 1-dependent autophagy and suppress Mtb elimination in macrophages. Specific Aim 2. Determine whether and how autophagy inhibits type I interferon (IFN) responses associated with progression to active disease. We will test whether autophagy prevents induction of type I IFN associated with active TB, and how this affects TB pathogenesis. Specific Aim 3. Define whether and how cellular neutral lipid loads affect autophagic control of Mtb. To determine how intrinsic host factors (in the absence of HIV) influence autophagy's ability to maintain a host- protective state-i.e. the LTBI status-we will tes whether host cell lipid stores and imbalances in cellular lipid loads affect autophagic control of Mtb.