The molecular mechanism for trypanosome cell death induced by ApoLI and its inactivation in human infective T. b. rhodesiense.

ApoLI 诱导锥虫细胞死亡的分子机制及其在人类感染性锥虫中的失活。

• 批准号: MR/P001424/1
• 负责人: Matthew Higgins
• 金额: $ 110.77万
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2016
• 资助国家: 英国
• 起止时间: 2016 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=MR%2FP001424%2F1
• 关键词: molecular; mechanism; trypanosome; cell; death

Trypanosomes are deadly, single celled parasites that are injected into the blood of humans, domestic livestock and wildlife when bitten by infected tsetse flies. They cause sleeping sickness in humans and wasting diseases in livestock, including nagana in cattle. These diseases have significant impact in sub-Saharan Africa. They lead to thousands of human deaths and cause significant human suffering by reducing the productivity of livestock. Most species of African trypanosomes cannot infect humans, due to two molecular complexes found in human blood, known as trypanolytic factors. These contain a shared component, apolipoprotein LI (ApoLI) which kills the trypanosomes. ApoLI can punch holes in the membranes of the parasite, leading to death of the cell. The two subspecies of trypanosome that infect humans and cause sleeping sickness are able to inactivate ApoLI and can therefore survive in human blood and cause disease.How ApoLI kills trypanosomes is not well understood. It is well established that ApoLI punches holes in membranes but it is not clear which membranes within the trypanosome cell are damaged. Some studies suggest that ApoLI bursts the lysosome, a compartment of the cell used to degrade cellular components. Others suggest that it punches holes in the outer cell membrane, while further studies suggest that it is the mitochondria, the energy 'power-houses' of the cell, that are damaged. We will use the latest microscopy methods to observe ApoLI as it moves around the cell, and to see what parts of the cell are affected, and how they are killed.The mechanism used by ApoLI to punch holes is also not well understood. How does it interact with membranes and how does it form pores? How are these pores regulated? These questions are important for understanding how ApoLI kills trypanosomes. They are also important in understanding the natural function of ApoLI in the human body, as it is known that changes in ApoLI are associated with late-onset kidney disease. We will use structural biology methods to understand what ApoLI looks like, and to perform a variety of studies to see the mechanism by which it forms pores.We will also study one of the two human infective species of trypanosome, Trypanosoma brucei rhodesiense. This parasite can resist the toxic effects of ApoLI because of the presence of a single molecule, the serum resistance associated protein, SRA. We have shown that SRA can interact directly with ApoLI under a variety of conditions and now aim to determine exactly how it inactivates ApoLI. Does it bind to ApoLI to prevent it from getting to the region of the cell in which it mediates its toxic effects? Or does it bind to ApoLI and prevent it from forming pores? Or perhaps it is both? We will again use structural biology methods to understand exactly how ApoLI interacts with SRA, and how it stops pore formation by ApoLI. We will also use the latest microscopy methods to investigate how SRA moves around within trypanosomes that are exposed to ApoLI.These studies will provide molecule detail to allow us to understand how ApoLI kills trypanosomes and how human infective trypanosomes become resistant to this toxin. This has the potential to help us to design new therapeutics to prevent sleeping sickness. By understanding how SRA binds to and inhibits ApoLI, we can design new versions of ApoLI that are resistant to SRA-mediated inactivation. These can be supplied directly to sleeping sickness patients to kill trypanosomes. We can also develop small molecules that block the SRA-ApoLI interaction, allowing the bodies natural ApoLI-mediated defenses to kill the parasite. Finally, transgenic cattle are being developed which contain ApoLI to prevent trypanosome growth. Using versions of ApoLI which are resistant to SRA-mediated inactivation will decrease the chance of these cattle being infected and providing a reservoir for the growth and development of human infective trypanosomes.

锥虫是致命的单细胞寄生虫，当被感染的采采蝇咬伤时，被注射到人类，家庭牲畜和野生动植物的血液中。它们在人类中引起睡眠疾病，并在牲畜中浪费疾病，包括牛长纳纳（Nagana）。这些疾病对撒哈拉以南非洲有重大影响。它们导致数千人死亡，并通过降低牲畜的生产力来造成重大的人类痛苦。由于人类血液中发现的两个分子复合物（称为锥虫液化因子），大多数非洲锥虫物种无法感染人类。这些包含共享的成分，载脂蛋白LI（Apoli），该蛋白杀死了锥虫。 Apoli可以在寄生虫的膜上打孔，导致细胞死亡。感染了人类并引起睡眠的两个锥虫的亚种可以使阿波利失活，因此可以在人类血液中生存并引起疾病。阿波利如何杀死锥虫。众所周知，Apoli在膜上打孔，但尚不清楚锥虫细胞中哪些膜受损。一些研究表明，Apoli破坏了溶酶体，这是用于降解细胞成分的细胞的室。其他人则认为它会在外部细胞膜中打孔，而进一步的研究表明，它是线粒体，细胞的能量“电源”受损。我们将使用最新的显微镜方法在细胞周围移动时观察Apoli，并查看细胞的哪些部分受到影响，以及它们如何被杀死。Apoli用来打孔孔的机制也不是很好的理解。它如何与膜相互作用，如何形成毛孔？这些毛孔如何受到调节？这些问题对于理解Apoli如何杀死锥虫很重要。它们对于理解Apoli在人体的自然功能也很重要，众所周知，Apoli的变化与晚发肾病有关。我们将使用结构生物学方法来了解Apoli的外观，并进行各种研究以查看其形成毛孔的机制。我们还将研究锥虫锥虫锥虫Brucei Rhodesiense的两种人类感染性物种之一。由于存在单个分子，血清耐药性相关蛋白SRA，该寄生虫可以抵抗Apoli的毒性作用。我们已经表明，SRA可以在各种条件下直接与Apoli进行交互，现在旨在确定它如何使Apoli失活。它是否与Apoli结合以防止其进入介导其毒性作用的细胞区域？还是它与Apoli结合并防止其形成毛孔？也许两者都是？我们将再次使用结构生物学方法准确了解Apoli如何与SRA相互作用，以及它如何停止Apoli的孔形成。我们还将使用最新的显微镜方法来研究SRA如何在暴露于Apoli的锥虫中移动。这些研究将提供分子细节，以使我们能够了解Apoli如何杀死锥虫以及人类的人类感染性锥虫如何抗性对这种毒素。这有可能帮助我们设计新的治疗剂，以防止睡眠疾病。通过了解SRA如何与Apoli结合并抑制Apoli，我们可以设计新版本的Apoli，这些版本对SRA介导的失活具有抗性。这些可以直接提供给昏昏欲睡的患者以杀死锥虫。我们还可以开发出阻塞Sra-Apoli相互作用的小分子，从而使身体自然介导的防御能够杀死寄生虫。最后，正在开发含有apoli的转基因牛，以防止锥虫生长。使用对SRA介导的失活有抵抗力的Apoli版本将减少这些牛被感染的机会，并为人类感染性锥虫的生长和发展提供储层。

项目成果

A Receptor's Tale: An Eon in the Life of a Trypanosome Receptor.

• DOI: 10.1371/journal.ppat.1006055
• 发表时间: 2017-01
• 期刊: PLoS pathogens
• 影响因子: 6.7
• 作者: Higgins MK;Lane-Serff H;MacGregor P;Carrington M
• 通讯作者: Carrington M

Molecular mechanism of complement inhibition by the trypanosome receptor ISG65

• DOI: 10.1101/2023.04.27.538609
• 发表时间: 2024-02-02
• 期刊: bioRxiv
• 作者: Cook，Alexander D;Carrington，Mark;Higgins，Matthew K
• 通讯作者: Higgins，Matthew K

Evolutionary diversification of the trypanosome haptoglobin-haemoglobin receptor from an ancestral haemoglobin receptor.

锥虫触珠蛋白-血红蛋白受体从祖先血红蛋白受体的进化多样化。

• DOI: 10.7554/elife.13044
• 发表时间: 2016
• 期刊: eLife
• 影响因子: 7.7
• 作者: Lane-Serff H

O-h what a surprise.

哦，真是一个惊喜。

• DOI: 10.1038/s41564-018-0211-x
• 发表时间: 2018
• 期刊: Nature microbiology
• 影响因子: 28.3
• 作者: Carrington M

High-throughput hit-squad tackles trypanosomes

高通量打击小队应对锥虫

• DOI: 10.1016/j.pt.2021.07.005
• 发表时间: 2021
• 期刊: Trends in Parasitology
• 影响因子: 9.6
• 作者: Cook A