Elucidating Leishmania strategies for parasitophorous vacuole biogenesis

亚马逊利什曼原虫是南部和中部皮肤利什曼病的主要原因之一 美国。这种病原体给人类健康带来的负担与基础知识的缺乏形成了鲜明对比 关于其潜在的毒性和生存机制。特别是，亚马逊斑潜蝇是一种日益增长的公众 健康问题，因为感染这种寄生虫通常会造成弥漫的不可愈合的损伤，更罕见的是， 致命的内脏疾病，对标准治疗的抵抗力不断增强。这一范围广泛的 结果表明，这些寄生虫非常灵活，适应不同的宿主免疫反应。 亚马孙乳杆菌和墨西哥乳杆菌复合体的其他物种诱导形成专门化复制 受感染的巨噬细胞内的小生境。这个寄生性液泡(PV)增大，占据了大部分 被感染的巨噬细胞的细胞内空间；这一独特的特征对于寄生虫的生存和 复制。然而，这种扩大的PV的生物发生机制在很大程度上尚不清楚。这个 这个项目的长期目标是阐明驱动巨人生物发生的细胞机制 PV，并允许巨噬细胞内的无鞭毛体存活和复制。我们的假设是 无鞭毛体结合多种针对宿主SUMO化、ATP6V0D2和ATP6V0D2的毒力机制 受体CD36和CSF1R促进光伏生物发生，颠覆宿主防御，并协调获得 必需的代谢物，如脂类。请注意，所有利什曼原虫物种都将PV创建为安全的复制利基环境， 因此，不同的利什曼原虫也可以采用类似的策略来产生其PV。 物种，而不考虑PV大小。这一建议背后的基本原理是，对多个 控制光伏生物发生的机制将为更好地理解亚马孙乳杆菌如何成功 在一般不适宜居住的巨噬细胞内创造其复制的利基。这项建议意义重大，因为 由此产生的对寄生虫-宿主相互作用的更深层次的机械理解将导致对 新的方法来攻击这个关键的，但到目前为止无法摧毁的复制利基，无鞭毛体就是从这里触发的 利什曼病的外在症状。该提案是创新的，因为将调查3部小说 在我们早期的研究中发现的机制，与亚马逊无鞭毛体的生物发生有关 放大的PV。目的1将探讨CD36介导的脂类转运在将必需的脂类输送到或 从光伏上。在目标2中，我们将研究无鞭毛体触发的去SUMO如何诱导ATP6VOD2 表达，有利于寄生虫的生理需求，如增加胆固醇的可利用性。目标3将 关注CSF1R的研究，我们假设CSF1R被无鞭毛虫劫持，以支持对CSF1R的高需求 通过细胞内寄生虫的作用和/或控制血栓蛋白1的表达。

Leishmania amazonensis is one of the main causes of cutaneous leishmaniasis in South and Central America. The burden of this pathogen on human health contrasts with the lack of fundamental knowledge about its underlying virulence and survival mechanisms. In particular, L. amazonensis is a growing public health problem because infection with this parasite often creates diffuse non-healing lesions, and more rarely, lethal visceral disease, with increasing levels of resistance to standard therapies. This broad range of outcomes indicates that these parasites are extremely flexible and adapt to different host immune responses. L. amazonensis, and other species of the L. mexicana complex, induce the formation of specialized replication niche within infected macrophages. This parasitophorous vacuole (PV) is enlarged, occupying most of intracellular space of an infected macrophage; this unique feature is essential for parasite survival and replication. However, the mechanisms involved in biogenesis of this enlarged PV are largely unknown. The long-term objective of this project is to elucidate the cellular mechanisms that drive the biogenesis of the giant PV and allow the survival and replication of amastigotes within macrophages. Our hypothesis is that amastigotes combine multiple virulence mechanisms targeting host SUMOylation, ATP6V0D2 and the receptors CD36 and CSF1R to promote PV biogenesis, subvert host defense, and orchestrate the acquisition of essential metabolites, such as lipids. Note that all Leishmania species create PVs as safe replicative niches, therefore strategies used to L. amazonensis to generate its PV could be similarly used by different Leishmania species regardless of PV size. The rationale underlying this proposal is that a systematic study of the multiple mechanisms controlling PV biogenesis will provide a better understand how L. amazonensis successfully creates its replicative niche inside generally inhospitable macrophages. This proposal is significant because the resulting deeper mechanistic understanding of the parasite-host interaction will lead to the identification of new methods to strike at this critical, but so far indestructible, replicative niche from where amastigotes trigger the outward symptoms of leishmaniasis. The proposal is innovative because will investigate 3 novel mechanisms, identified in our earlier studies, involved in the biogenesis of the L. amazonensis amastigote enlarged PV. Aim 1 will explore the role of CD36 mediated lipid transport in delivering essential lipids to or from the PV. In Aim 2, we will study how amastigote-triggered deSUMOylation induces ATP6VOD2 expression, favoring parasite physiological demands such as increased cholesterol availability. Aim 3 will focus on the study of CSF1R, which we hypothesize is hijacked by amastigotes to support the high demand for sterols by intracellular parasites and/or to control the expression of Thrombospondin1.