Exploring the molecular regulation of host macrophage autophagy by leishmania

我们的研究计划是了解控制宿主-病原体相互作用的细胞生物学和免疫生物学的基本机制。我们使用利什曼原虫属的原生动物寄生虫作为模型病原体，人类巨噬细胞作为宿主细胞。我们的长期目标是确定利什曼原虫使用的策略来操纵宿主巨噬细胞环境，使其在吞噬溶酶体内存活。我们最近取得了两项重大进展。首先，我们发现利什曼原虫劫持宿主PI3K-Akt细胞信号通路，产生巨噬细胞前寄生表型。其次，我们发现利什曼原虫诱导选择性宿主巨噬细胞自噬，并通过激活PI3K-Akt通路微调这一过程以促进其存活。我们的短期目标是研究利什曼原虫使用巨噬细胞自噬来促进其生存的调节机制。自噬是一种基本的、必需的分解代谢过程，其特征是被双膜结构（称为自噬体）吞噬的细胞质成分的主动降解。长期以来，人们认为自噬是一种非选择性的循环途径。然而，最近已经确定自噬可以选择性和有效地降解特定的细胞成分。我们的假设是利什曼原虫需要特定的宿主大分子才能在宿主细胞内存活和生长。这些是通过诱导选择性自噬将所需的货物转移到含有利什曼原虫的吞噬溶酶体中来获得的。我们有三个目标：目标1。目的：对利什曼原虫诱导的自噬小体的蛋白质成分进行生化表征，并研究其在利什曼原虫与巨噬细胞相互作用中的作用。目标2。探讨利什曼原虫诱导选择性自噬的机制。目标3。鉴定参与经典宿主自噬衰减的利什曼原虫PI3K激活因子。这个基础科学研究项目将通过描述一种用于逃避细胞内免疫的新机制，显著提高我们对宿主防御和微生物发病机制的认识。我们预计所产生的知识将广泛适用于宿主-病原体相互作用领域。这项研究计划的直接成果之一将是培养两名博士生。他们将有机会使用广泛的先进技术，如定量蛋白质组学、分子和细胞生物学，并培养设计和执行复杂实验所需的批判性思维。这将使他们成为学术界或私营部门的科学家。这一研究项目将促进自然科学和工程领域的卓越研究，促进高质量的培训，创造新的就业机会。

Our research program is to understand the fundamental mechanisms that govern the cell biology and immunobiology of host-pathogen interactions. We use a protozoan parasite of genus Leishmania as our model pathogen, and human macrophages as host cells. Our long term objective is to identify the strategies used by Leishmania to manipulate the host macrophage environment to be permissive for their survival inside phagolysosomes. We recently made two major advances. First, we discovered Leishmania hijacks the host PI3K-Akt cell signaling pathway to generate macrophage proparasitic phenotypes. Second, we discovered that Leishmania induces selective host macrophage autophagy, and fine-tunes this process to promote their survival by activating the PI3K-Akt pathway. Our short term objectives are to investigate the mechanisms of regulation of macrophage autophagy used by Leishmania to promote their survival.Autophagy is a fundamental, essential catabolic process characterized by the active degradation of cytoplasmic constituents that are engulfed by double membrane structures, known as autophagosomes. It was long thought that autophagy was a non-selective recycling pathway. However, recently it has been established that autophagy can selectively and efficiently degrade specific cellular constituents.Our hypothesis is that Leishmania needs specific host macromolecules to survive and grow inside host cells. These are obtained by inducing selective autophagy to transfer required cargo to Leishmania-containing phagolysosomes. We have three objectives:Objective 1. To biochemically characterize protein constituents of Leishmania induced autophagosomes and to study their roles in Leishmania-macrophage interaction.Objective 2. To investigate the mechanism of selective autophagy induction by Leishmania.Objective 3. To identify Leishmania PI3K activator(s) involved in the attenuation of classical host autophagy.This basic science research program will significantly advance our knowledge of host defense and microbial pathogenesis by characterizing a novel mechanism used to evade intracellular immunity. We anticipate that the knowledge generated will be broadly applicable to the area of host-pathogen interactions. One of the immediate outcomes of this research program will be the training of two doctoral students. They will have opportunities to work with a wide range of advanced techniques such as quantitative proteomics, molecular and cell biology and to develop critical thinking required in designing and executing complex sets of experiments. This will equip them for careers as scientists in academia or in the private sector. Together this research program will foster research excellence in the natural sciences and engineering, stimulate high quality training and create new employment opportunities.