Macrophage-Activating MicroRNAs In the Pathogenesis of Leishmaniasis

利什曼原虫。原生动物对它们入侵的宿主细胞有深远的影响。这些 寄生虫通常居住在巨噬细胞内，巨噬细胞是一种能够杀死细胞内的细胞类型。 微生物。利什曼原虫非但没有屈服，反而使宿主细胞的杀菌途径瘫痪， 将巨噬细胞从致命细胞转变为细胞内的安全避风港，从而允许寄生虫 存活、复制并最终扩散到邻近细胞。通过这个机制(S) 寄生虫“麻痹”宿主的杀菌功能尚不完全清楚。 最近发现，大多数真核生物利用短的非编码RNA 用于全球调控多种基因表达的序列。确实是短的RNA序列 长度为18-30个碱基的称为microRNAs，对于调节大约30%的 人类基因组。这个提议背后的假设是，microRNAs是 上游触发(S)确定巨噬细胞激活的哪种模式 利什曼原虫感染。我们将解决以下问题。(1)哪些microRNAs参与 寄生虫通常在感染巨噬细胞时诱导或抑制？(2)哪些microRNAs是 对激活巨噬细胞朝向不同极性表型的刺激的反应？(3)是 在AIMS 1和AIMS 2中发现的microRNAs之间存在重叠， 这些microRNA对感染利什曼原虫的巨噬细胞的实验操作？具体目标 建议的内容包括： 1.对响应于以下条件引起的microRNA表达的变化进行全局分析 人巨噬细胞对查格氏杆菌的吞噬作用。 2.使用类似的分析方法来确定哪些microRNA被诱导来响应 巨噬细胞对不同极化表型的激活。最感兴趣的将是 在M1(经典)激活过程中发生的microRNA变化，以及其他 巨噬细胞激活的形式，因为经典激活的巨噬细胞可以杀死细胞内 利什马尼亚。 3.关联目标1和目标2的结果，并选择性地过度表达或抑制 巨噬细胞表达可能改变巨噬细胞模式的特定microRNAs 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.