Regulating the trans-regulators: Investigating the PRMT7 molecular pathway as an epigenetic regulator of Leishmania spp. virulence

利什曼原虫的物种威胁着全球四大洲的3.5亿人。利什曼病是第二种最致命的寄生虫病，这种多样化疾病的所有病理在巴西都存在。世界卫生组织估计，目前全球有1200万人感染，每年新增病例超过100万例。目前没有疫苗存在，现有的利什曼病治疗方法受到日益增长的耐药性的威胁，而且往往被发病率和严重性不断增加的急性流行病所淹没。迫切需要新的治疗方法和疫苗，英国和巴西政府致力于响应世界卫生组织最近的呼吁，进一步支持被忽视的热带病研究。单细胞利什曼原虫在其生命周期中转化为许多不同的形式，以适应非常不同的宿主；从哺乳动物到沙蝇，再通过白蝇的叮咬回到哺乳动物。只有某些生命周期阶段的利什曼原虫才能在人类体内感染和存活。利什曼原虫的外观、新陈代谢和毒力在这些转变期间发生了重大变化，使它们能够存活。利什曼原虫的基因表达几乎完全依赖于mRNA的调节。作为对环境变化的反应，特定的寄生虫蛋白结合mRNAs，并将其作为蛋白质生产的靶标，以引导和促进适应。控制这些寄生虫适应的蛋白质使它们能够在人体内生存并感染人类。这些蛋白质对于利什曼原虫感染的毒力和传播是必不可少的。我们最近分离出了一种主要的控制面板“调节”蛋白PRMT7，它控制哺乳动物感染中利什曼原虫的毒力。利什曼原虫调节蛋白的鉴定很少，这一发现代表着分离和研究这一调节途径并阻断寄生虫毒力的重大飞跃。为了研究PRMT7调控途径并确定该蛋白的功能，我们组建了一个专家团队，研究利什曼原虫PRMT蛋白、RNA调节因子和蛋白质相互作用。我们相信，对这一途径的洞察将使我们能够阻止寄生虫建立人类感染。我们已经鉴定了一些PRMT7的下游靶蛋白，现在试图确定它们是否受PRMT7的调控，以及它们是否参与利什曼原虫的毒力。利什曼原虫蛋白与人类蛋白不同，因此我们可以利用这些差异来靶向利什曼原虫特有的毒力因子，阻断它们的功能，阻止利什曼原虫病的发展。重要的发现将为利什曼病的研究以及由相关寄生虫、恰加斯病和非洲锥虫病引起的疾病提供洞察力。我们建议寻找更多利什曼原虫的调节者。使用PRMT7毒力途径的毒力。我们将确定这些调节器是如何发挥作用的，并测试它们是否对寄生虫的生存至关重要。本项目的新颖性和重要性有四个方面：1.PRMT7是利什曼原虫中唯一的精氨酸甲基转移酶蛋白。到目前为止，它可以寄生寄生虫，而且似乎可以阻止毒力(Ferreira等人，2014年)。2.甲基化作为一种蛋白质修饰在利什曼原虫中没有特征。寄生虫。3.调节RNA结合蛋白(RBPs)在利什曼原虫中很大程度上是未知的，这些蛋白在寄生虫的生命周期分化、人类感染性和毒力方面具有重要作用。限制性商业惯例和信使核糖核酸的三维分子结构：蛋白质复合体在所有寄生虫中基本未知，在利什曼原虫中也不存在。

Species of Leishmania threaten 350 million people worldwide on four continents. The Leishmaniases are the second deadliest parasitic disease and all pathologies of this diverse disease are present in Brazil. The World Health Organisation estimates 12 million people globally are currently infected and over 1 million new cases occur annually. No vaccine currently exists and available Leishmaniasis treatments are threatened by growing resistances and often overwhelmed by acute epidemics that are increasing in occurrence and severity. New treatments and vaccines are desperately needed and the UK and Brazilian governments are committed to the World Health Organisation's recent call to further support Neglected Tropical Disease research.The single-cell Leishmania parasite transforms into many different forms during its lifecycle to adapt to very different hosts; moving from mammals to sandflies and back to mammals by sandfly bites. Only Leishmania parasites of certain lifecycle stage forms can infect and survive in humans. Major changes to the Leishmania parasite's appearance, metabolism and virulence occur during these transitions that enable them to survive. Gene expression in Leishmania relies almost exclusively upon mRNA regulation. In response to changes in the environment, specific parasite proteins bind mRNAs and target them for protein production to guide and promote adaptation. Proteins that control the adaptation of these parasites enable them to survive in and infect humans. Such proteins are essential for the virulence and spread of the Leishmania parasite infection. We have recently isolated a major control panel "Regulator" protein, PRMT7, which controls Leishmania parasite virulence in mammalian infections. Very few Leishmania regulator proteins have yet been identified and this finding represents a major leap forward to isolate and examine this regulatory pathway and block parasite virulence. To study the PRMT7 regulation pathway and identify the way this protein functions, we have assembled a team of experts in Leishmania parasite PRMT proteins, RNA regulators and protein interactions. We believe insight into this pathway will enable us to block the parasite from establishing human infections. We have identified some downstream target proteins of PRMT7 and now seek to determine if they are regulated by PRMT7 and whether they participate in Leishmania parasite virulence. Leishmania proteins are different from human proteins; therefore we can use these differences to target Leishmania- specific virulence factors, block their function and block Leishmaniasis from developing. Significant findings will provide insight to Leishmaniasis research as well as diseases caused by related parasites, Chagas Disease and African Trypanosomiasis.We propose to find more regulators of Leishmania spp. virulence using the PRMT7 virulence pathway. We will identify how these regulators function, and test whether any are essential for parasite survival. Essential Regulators could serve as potential drug targets to block Leishmania parasite infection.The novelty and importance of our project is four fold:1. PRMT7 is the only Protein aRginine Methyl Transferase enzyme that has been characterised in Leishmania spp. parasites thus far and it appears to block virulence (Ferreira et al., 2014). 2. Methylation as a protein modification is uncharacterised in Leishmania spp. parasites. 3. Regulatory RNA binding proteins (RBPs) that are important in parasite lifecycle differentiation, human infectivity and virulence are largely unknown in Leishmania spp.4. The 3-dimensional molecular structures of RBPs and mRNA:protein complexes are largely unknown in all parasites and are absent in Leishmania spp.