Unveiling the protein landscape of the African trypanosome cell surface and chasing down potential targets for therapeutic intervention

被忽视的热带疾病是主要在世界最贫穷人口中流行的一组不同疾病。世界卫生组织10种最重要的被忽视的热带疾病中的三种-非洲锥虫病（也称为昏睡病），利什曼病和恰加斯病-都是由密切相关的单细胞寄生虫引起的。人类感染非洲锥虫是由于受感染的采采蝇吸食了血液。如果不治疗，疾病会从一般的健康状况恶化到昏迷和死亡。目前使用的抗锥虫药物是旧的、有毒的，并且由于出现耐药性而失效。迫切需要进行新的研究，以确定潜在的新的治疗方案。非洲锥虫的一个不寻常的方面是，它们在人体防御系统的全面视野下在人体血液中繁殖。它们通过周期性地改变细胞表面来逃避宿主的识别。然而，寄生虫表面上的许多分子执行基本功能并且不能改变。锥虫将它们放置在细胞表面的一个特殊的受保护区域。识别表面暴露不变的分子和了解如何保持这种保护隔离是主要的科学兴趣，以及在发现的方式，锥虫可能容易受到新的therapy.Using由MRC资助的组合方法的实际效用，我以前已经确定了非洲锥虫细胞表面的组成。我现在的目标是利用这些知识，挑出那些不变的表面分子，这些分子对寄生虫在感染期间的生存至关重要。为此，我建议利用现代DNA测序技术的一些力量来测试哪些细胞表面基因在沉默时会导致寄生虫在宿主体内死亡。类似的方法将不仅用于识别细胞表面基因，而且用于识别寄生虫用于维持细胞表面组织的任何基因，这对于逃避宿主免疫攻击至关重要。最后，我建议测试这些表面暴露的分子作为疫苗的潜力。我的初步实验表明，我可以使用转基因寄生虫来筛选寄生虫表面上的分子，这些分子是免疫系统可以接触到的。我建议开发这种检测方法，并在人类疾病的动物模型中测试最有希望的候选人。拟议的工作将增加我们对重要人类寄生虫的基本生物学的理解，并且通过暴露重要的表面分子，为开发新的治疗方法提供第一步。

Neglected tropical diseases are a diverse group of diseases that thrive mainly among the poorest of the world's populations. Three of the World Health Organisation's 10 most significant neglected tropical diseases - African trypanosomiasis (also known as sleeping sickness), leishmaniasis, and Chagas' disease - are caused by closely-related single-celled parasites. Human infection with African trypanosomes is brought about when an infected tsetse fly takes a blood meal. Without treatment the disease progresses through general ill health to coma and death. Current drugs in use against trypanosomes are old, toxic and failing due to emergence of resistance. Urgent new research is needed to identify potential new therapeutic options.An unusual aspect of African trypanosomes is that they multiply in the human blood in full view of the body's defence systems. They do this by periodically changing their cell surface to escape recognition by the host. However, many molecules on the parasite surface perform essential functions and cannot be changed. Trypanosomes place these in a special, protected domain on the cell surface. Identifying surface-exposed invariant molecules and understanding how this protective segregation is maintained are of major scientific interest, as well as of practical utility in uncovering ways in which trypanosomes may be vulnerable to new therapies.Using a combinatorial approach funded by the MRC, I have previously identified the composition of the African trypanosome cell surface. I now aim to exploit this knowledge to single out those invariant surface molecules that are essential to the survival of the parasite during infection. For this, I propose to harness some of the power of modern DNA sequencing technologies to test which cell surface genes, when silenced, cause the parasite to die inside the host. A similar method will be used to identify not only cell surface genes, but any genes that the parasite uses to maintain the cell surface organisation, which is so critical to escaping the host immune attack. Finally, I propose to test those surface-exposed molecules for their potential as vaccines. My pilot experiments show that I can use genetically-modified parasite to screen for molecules on the parasite surface that are accessible to the immune system. I propose to develop this assay and test the most promising candidates in an animal model of human disease.The proposed work will increase our understanding of the fundamental biology of a significant human parasite, and also, by exposing essential surface molecules, provide the first steps in developing new treatments.