Autophagy Against Tuberculosis and HIV

描述（由申请人提供）： 结核病和后天免疫机能丧失综合症（艾滋病）是具有特殊公共卫生意义的疾病。全球结核病和艾滋病共同流行进一步突出了它们的重要性。结核分枝杆菌（Mtb）和人类免疫缺陷病毒（HIV）各自病原体的共同感染改变了由每种感染剂单独引起的疾病的进程。通常情况下，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。相反，建立了受控的、持久的无症状感染，称为潜伏性TB感染（LTBI）。设立长期制裁倡议和 进展为活动性疾病的驱动因素尚未完全了解。需要以前从未尝试过的方法来推动该领域的发展。在本申请中，我们将采取一种新的方法，通过证明自噬在维持LTBI和进展为活动性TB之间的平衡中的关键作用，以及作为HIV-Mtb共感染期间病毒靶向的过程。自噬是一种新近认识到的但仍是进化的古老的先天免疫机制，其作为细胞自主防御多种细胞内病原体，包括结核分枝杆菌。我们已发表的工作和其他人的研究表明，自噬，当适当诱导时，是一种重要的抗Mtb细胞自主先天免疫防御。我们认为自噬可以防止疾病进展为活动性疾病，并有利于LTBI。宿主保护作用基于自噬的两种效应子功能：首先，它消除胞内Mtb，其次，它抑制致病性细胞因子应答。在这个项目中，我们将测试自噬维持宿主保护状态并防止进展为活动性TB的假设，而内在宿主因素或HIV共感染干扰自噬并促进临床上明显的TB。如果这一假设是正确的，本项目中确定的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。本申请的具体目标是：具体目标1。确定HIV是否以及如何干扰共感染巨噬细胞中Mtb的自噬消除。从机制上讲，我们将定义HIV蛋白Nef及其等位基因在临床HIV分离株中的作用，并测试其抑制Beclin 1依赖性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与疾病进展相关的I型干扰素（IFN）反应。我们将测试自噬是否阻止与活动性TB相关的I型IFN的诱导，以及这如何影响TB发病机制。具体目标3。定义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。为了确定内在宿主因素（在不存在HIV的情况下）如何影响自噬维持宿主保护状态（即LTBI状态）的能力，我们将测试宿主细胞脂质储存和细胞脂质负荷的不平衡是否影响Mtb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.