Leishmania RNA viruses and pathogenesis

项目总结。 此前我们证明，在实验动物模型中，双链RNA病毒LRV1的存在可以感染 依赖于TLR3的利什曼原虫致病和转移增加 炎症反应。这一发现与人类的相关性是由最近的发现确定的 感染携带LRV1病毒的利什曼原虫的患者也显示出药物治疗失败的频率增加 病理和细胞因子反应增强。在这里，我们将这些研究扩展到巴西乳杆菌，首先通过 开发新的动物模型和工具。新发现的布尼亚病毒样病毒“TOP”将是最高的 优先；TOP出现在&gt；95%的巴西乳杆菌菌株和大多数相关的万年青 物种。大量的初步数据表明，在毒力方面有很强的作用，潜在地超过了LRV1。在……里面 目的1研究LRV1和TOP依赖的毒力机制。精心挑选的一系列等基因系 将建立显示LRV1和/或TOP(病毒型)的不同组合及其毒力 特色化的。然后这些将被用来探索依赖LRV1的毒力的机制，这是 与类似于I型干扰素诱导的强烈巨噬细胞反应有关。顶部依赖 毒力似乎通过一种完全不同的机制发挥作用，独立于干扰素，很可能 涉及树突状细胞。在目标2中，我们专注于分子病毒学，尤其是TOP，因为这些研究很可能 为直接抑制这些病毒的努力提供信息。我们确定TOP是一个高度不同的谱系 布尼亚病毒科的新科，命名为“利什布尼亚病毒科”。由于这些新奇的特征恰好出现在 利什曼原虫从单性寄生向双性/脊椎动物寄生转变的进化深度时期， 这些结构上的差异可能有助于顶级致病机制。我们将探索他们的 编码潜力和预测蛋白质的存在和作用(S)，并使用遗传学方法实现功能 测试它们在病毒复制和毒力中的作用。

Project summary. Previously we showed that in experimental animal models, the presence of the dsRNA virus LRV1 infecting strains of Leishmania guyanensis confers elevated pathology and metastasis, mediated by a TLR3-dependent inflammatory response. The relevancy of this finding to humans was established by recent findings that patients infected with Leishmania bearing LRV1 show an elevated frequency of drug treatment failures, as well increased pathology and cytokine responses. Here we extend these studies to L. braziliensis, first by developing new animal models and tools. The newly discovered bunyavirus- like virus “TOP” will be a high priority; TOP occurs in >95% of all L. braziliensis strains examined and the majority of related Viannia species. Extensive preliminary data suggest a strong role in virulence, potentially exceeding that of LRV1. In Aim 1 we will study mechanisms of LRV1- and TOP-dependent virulence. A well-chosen series of isogenic lines showing different combinations of LRV1 and/or TOP (virotypes) will be established and their virulence characterized. These will then be used to probe the mechanism of LRV1-dependent virulence, which is associated with a strong macrophage response similar to that induced by type I interferons. TOP-dependent virulence seems to act through a completely different mechanism, independent of interferon and likely involving dendritic cells. In Aim 2 we focus on molecular virology, especially of TOP, as these studies will likely inform efforts to inhibit these viruses directly. We established that TOP is a highly divergent lineage within a new family of the Bunyavirales termed “Leishbunyaviridae”. Since these novel features arose precisely at the time deep in evolution when Leishmania transitioned from monxenous to dixenous/vertebrate parasitism, these structural differences are likely to contribute to the TOP pathogenic mechanism. We will explore their coding potential and the existence and role(s) of predicted proteins, and use genetic approaches to functional test their role in viral replication and virulence.