Determining the role of sphingolipids in Mycobacterium tuberculosis infection

项目总结/摘要 近三分之一的世界人口感染结核分枝杆菌（Mtb）， 结核病（TB）。这一水库导致结核病发病率不断上升， 每年新增病例和180万例死亡。结核分枝杆菌在引起疾病方面的巨大成功取决于其 有效利用宿主脂质代谢（包括鞘脂生物合成途径）的能力， 破坏免疫系统肉芽肿是结核病感染的病理标志，其特征在于： 存在脂质负载的免疫细胞，例如具有显著降低的能力的泡沫状巨噬细胞 控制细菌生长。尽管已知Mtb调节脂质代谢，特别是脂质代谢。 在感染过程中的鞘脂途径，没有系统的了解感染性细菌如何改变 宿主脂质体。我们最近发现，鞘脂，一类独特的脂质与鞘碱骨干 在细胞膜中富集，对于Mtb的进入和杀死是必需的。我们计划扩大我们的 研究以确定每种鞘脂库在Mtb发病机制中的作用。的主要目标 拟议的工作是系统地干扰宿主的关键鞘脂生物合成途径， 它们在Mtb发病机理和抗微生物细胞过程如炎性小体中的功能。为此 目的，单个敲除巨噬细胞系缺乏参与生物合成的关键基因， 将使用CRISPR/Cas9技术产生鞘脂。我们将使用多功能鞘脂 前体类似物，以确定流量，定位和鞘脂的相互作用组在感染的时间- 和空间依赖的方式。此外，我们将研究鞘脂在 炎性小体是一种先天免疫过程，在控制Mtb感染中很重要。了解这些 对Mtb的发病机制至关重要的途径或过程是至关重要的，因为它们代表了Mtb的潜在靶点。 新疗法

Project Summary/Abstract Nearly one-third of the world population is infected with Mycobacterium tuberculosis (Mtb), the causative agent of tuberculosis (TB). This reservoir contributes towards an increasing incidence of TB, with about 11 million new cases and 1.8 million deaths every year. The profound success of Mtb in causing disease depends on its ability to effectively utilize the host's lipid metabolism, including the sphingolipid biosynthesis pathway, to subvert the immune system. The granuloma, the pathological hallmark of TB infection, is characterized by the presence of lipid-loaded immune cells such as foamy macrophages that have a significantly reduced capability in controlling bacterial growth. Although Mtb is known for modulating lipid metabolism, and in particular the sphingolipid pathways during infection, there is no systematic understanding of how infective bacteria alter the host lipidome. We recently found that sphingolipids, a distinct class of lipids with a sphingoid base backbone that are enriched in cellular membranes, are essential for entry and killing of Mtb. We plan to extend our investigation to define the role of each sphingolipid repertoire in Mtb pathogenesis. The main goal of the proposed work is to systematically perturb the key sphingolipid biosynthetic pathways of the host to uncover their function in Mtb pathogenesis and antimicrobial cellular processes such as the inflammasome. For this purpose, individual knockout macrophage cell lines that lack key genes involved in the biosynthesis of sphingolipids will be generated using CRISPR/Cas9-technology. We will use multifunctional sphingolipid precursor analogs to define the flux, localization and the interactome of sphingolipids during infection in time- and space-dependent manner. Furthermore, we will study the significance of sphingolipids in the inflammasome, an innate immune process that is important in controlling Mtb infection. Understanding these pathways or processes essential for the pathogenesis of Mtb is crucial, as they represent potential targets for new therapeutics.