Leishmania amazonensis Engages CD36 to Drive Parasitophorous Vacuole Maturation.
Leishmania amazonensis Engages CD36 to Drive Parasitophorous Vacuole Maturation.
复制标题
DOI：
10.1371/journal.ppat.1005669
复制
发表时间：
2016-06
期刊：
影响因子：
6.7
通讯作者：
Silverman N
中科院分区：
文献类型：
--
作者：
Okuda K;Tong M;Dempsey B;Moore KJ;Gazzinelli RT;Silverman N
利什曼原虫无鞭毛体操纵巨噬细胞的活性，以促进自己的成功。然而，很少有人知道的先天识别和无鞭毛体在这种宿主-寄生虫相互作用引发的信号转导的作用。在这项工作中，我们开发了一个新的感染模型，在成年果蝇，利用其上级遗传资源，以确定新的宿主因素限制亚马逊利什曼原虫感染。该模型是基于巨噬细胞样细胞，浆细胞，吞噬和控制寄生虫注入成年苍蝇的增殖的能力。使用该模型，我们筛选了一组表达RNAi的果蝇的抗利什曼原虫防御因子。值得注意的是，我们发现了三个CD 36样清道夫受体，这是重要的防御利什曼原虫感染。在小鼠巨噬细胞中的机制研究表明，CD 36积累的网站，寄生虫接触寄生虫空泡膜。此外，CD 36缺陷型巨噬细胞在形成L.亚马逊感染，由与晚期内体和/或溶酶体的无效融合引起的表型。这些数据确定了一个前所未有的作用，CD 36在寄生虫空泡的生物发生，并进一步强调了果蝇作为一个模型系统解剖先天性免疫反应感染的效用。利什曼病是由利什曼原虫寄生虫引起的，并通过白蛉传播给人类。在感染建立后，细胞内寄生虫形式，称为无鞭毛体，优先感染巨噬细胞并在巨噬细胞中复制，巨噬细胞是专门用于杀死微生物的细胞。为了克服巨噬细胞的致命性，利什曼原虫拥有一种复杂的逃避策略，破坏巨噬细胞的防御。利什曼原虫-巨噬细胞相互作用的细胞生物学尚未完全了解，因为宿主-寄生虫关系的复杂性和经典小鼠感染模型中可用的技术资源有限。本研究建立了一种果蝇利什曼病模型，该模型具有遗传易处理、成本低、高保守性等优点。通过筛选一批转基因果蝇，CD 36样受体被鉴定为参与利什曼原虫-吞噬细胞相互作用的因子。在CD 36缺陷型小鼠巨噬细胞中的进一步测试表明，由于寄生虫无法扩大寄生虫空泡，它们不支持寄生虫增殖，这是一种用于避免活性氮物质毒性的策略。CD 36参与控制嗜寄生虫空泡，这是一种改变的吞噬体，对疾病如阿尔茨海默病，动脉粥样硬化和某些细菌感染有进一步的影响，其中CD 36是已知的吞噬受体。
Leishmania amastigotes manipulate the activity of macrophages to favor their own success. However, very little is known about the role of innate recognition and signaling triggered by amastigotes in this host-parasite interaction. In this work we developed a new infection model in adult Drosophila to take advantage of its superior genetic resources to identify novel host factors limiting Leishmania amazonensis infection. The model is based on the capacity of macrophage-like cells, plasmatocytes, to phagocytose and control the proliferation of parasites injected into adult flies. Using this model, we screened a collection of RNAi-expressing flies for anti-Leishmania defense factors. Notably, we found three CD36-like scavenger receptors that were important for defending against Leishmania infection. Mechanistic studies in mouse macrophages showed that CD36 accumulates specifically at sites where the parasite contacts the parasitophorous vacuole membrane. Furthermore, CD36-deficient macrophages were defective in the formation of the large parasitophorous vacuole typical of L. amazonensis infection, a phenotype caused by inefficient fusion with late endosomes and/or lysosomes. These data identify an unprecedented role for CD36 in the biogenesis of the parasitophorous vacuole and further highlight the utility of Drosophila as a model system for dissecting innate immune responses to infection. Leishmaniasis is caused by Leishmania parasites and transmitted to humans by sandflies. After the establishment of infection, the intracellular parasite form, known as an amastigote, preferentially infects and replicates in macrophages, cells otherwise specialized for killing microbes. To overcome macrophage lethality, Leishmania possesses a sophisticated evasion strategy that sabotages macrophage defenses. The cell biology of Leishmania-macrophage interactions is not completely understood, because of the complexity of the host-parasite relationship and limited technical resources available in the classical mouse infection model. In this study we created a model of leishmaniasis in fruit flies, which have advantages of genetic tractability, low cost, and high conservation. By screening a collection of genetically modified flies, CD36-like receptors were identified as factors involved in the Leishmania-phagocyte interaction. Further testing in CD36-deficient mouse macrophages showed that they did not support parasite proliferation due to the inability of parasites to enlarge the parasitophorous vacuole, a strategy used to avoid toxicity of reactive nitrogen species. The participation of CD36 in the control of the parasitophorous vacuole, which is an altered phagosome, has further implications for diseases such as Alzheimer’s disease, atherosclerosis, and certain bacterial infections where CD36 is a known phagocytic receptor.