Macrophage-Activating MicroRNAs In the Pathogenesis of Leishmaniasis

利什曼原虫属原生动物对它们入侵的宿主细胞有着深远的影响。这些 寄生虫通常存在于细胞内的巨噬细胞中，巨噬细胞是一种具有杀死细胞内 微生物利什曼原虫不是屈服，而是麻痹宿主细胞的杀微生物途径， 将巨噬细胞从致死细胞转变为细胞内的避风港， 存活、复制并最终扩散到邻近的细胞。通过何种机制， 寄生虫“麻痹”宿主的杀微生物功能还不完全清楚。 最近发现大多数真核生物利用短的非编码RNA 序列来全局调节多种基因的表达。短RNA序列 长度为18-30 bp，称为microRNA，对调节约30%的 人类基因组这一假设的基础是，microRNA是 上游触发器确定在巨噬细胞活化之后将发生哪种模式 利什曼原虫感染。我们将讨论以下问题。(1)什么样的microRNAs 寄生虫在感染巨噬细胞过程中通常是诱导还是抑制？(2)哪些microRNAs 对刺激物的反应是诱导巨噬细胞向不同极性表型活化？(3)是 目标1和2中发现的microRNA之间存在重叠， 实验操作这些微小RNA对利什曼感染的巨噬细胞？具体目标 建议的内容包括： 1.为了对响应于以下因素诱导的microRNA表达的变化进行全局分析： L.吞噬作用chagasi由人类巨噬细胞。 2.为了使用类似的分析方法来确定哪些microRNA是响应于 巨噬细胞活化朝向不同极化表型。主要的兴趣将是 在M1（经典）激活过程中发生的microRNA变化与其他基因的相互变化 巨噬细胞活化的形式，因为经典活化的巨噬细胞可以杀死细胞内 利什曼原虫 3.将目的1和2的结果相关联，并选择性地过表达或抑制 巨噬细胞表达选定的microRNA，可能会改变巨噬细胞的模式， 激活或细胞内寄生虫生长。

The Leishmania spp. protozoa have a profound effect on the host cell that they invade. These parasites reside intracellularly usually in macrophages, a cell type with the capacity to kill intracellular microbes. Rather than succumb, Leishmania paralyze the microbicidal pathways of the host cell, changing the macrophage from a lethal cell to an intracellular safe haven which allows the parasite to survive, replicate and ultimately spread to neighboring cells. The mechanism(s) through which the parasite "paralyzes" the host microbicidal function is incompletely understood. It has recently come to light that most eukaryotic organisms utilize short noncoding RNA sequences to globally regulate expression of a wide variety of genes. Indeed short RNA sequences of 18-30 bp in length, called microRNAs, are critical for regulating expression of an estimated 30% of the human genome. The hypothesis underlying this proposal is that microRNAs are the upstream trigger(s) determining which pattern of macrophage activation will occur after Leishmania infection. We will address the following questions. (1) What microRNAs does the parasite usually induce or suppress during infection of macrophages? (2) Which microRNAs are induced in response to stimuli that activate macrophage toward different polar phenotypes? (3) Is there overlap between the microRNAs discovered in Aims 1 and 2, and what is the effect of experimental manipulation of these microRNAs on Leishmania-infected macrophages? Specific aims of the proposal are: 1. To perform a global profiling of changes in microRNA expression induced in response to phagocytosis of L. chagasi by human macrophages. 2. To use a similar profiling approach to determine which microRNAs are induced in response to macrophage activation toward different polarized phenotypes. Of primary interest will be the microRNA changes that occur during M1 (classical) activation with reciprocal changes in other forms of macrophage activation, since classically activated macrophages can kill intracellular Leishmania. 3. To correlate the results of Aims 1 and 2, and to selectively either overexpress or suppress macrophage expression of selected microRNAs that may change in the pattern of macrophage activation or intracellular parasite growth.