Multiscale analysis of MyosinA-based motility in Toxoplasma gondii

弓形体脑炎(TE)是一种危及艾滋病患者生命的脑部感染，由 机会性病原体，弓形虫。在这些地区有治疗急性弓形虫感染的药物 并抑制其在慢性感染者中的再次出现，但对许多患者来说， 这些药物的不良反应很严重，导致它们停止使用。因此，有必要开发新的、 耐受性更好的药物用于治疗艾滋病相关的TE。这反过来又需要更好地了解T。 弓形虫及其毒力背后的机制，使寄生虫生命中的临界点 周期可以被识别和定位。 弓形虫的生活周期阶段负责疾病的致病，速殖子，是高度能动性的。 速殖子运动是宿主细胞入侵、跨越生物屏障和传播所必需的。 通过宿主组织。弓形虫肌球蛋白A(TgMyoA)是一种非传统的肌球蛋白马达蛋白，它发挥着中枢作用。 在寄生虫运动中起作用，缺乏TgMyoA的速殖子是完全无毒的。这个项目的首要目标是 项目是促进我们对速殖子运动性的机械理解，并测试小分子 在动物感染模型中，以运动机械为靶点可以改善疾病。具体目标是 要：(1)确定改变TgMyoA运动功能的特定方面如何影响寄生虫的运动性，通过 最近发现的TgMyoA马达的小分子抑制剂如何影响其生物力学的特征 并将这些运动功能的变化与寄生虫3D运动的影响联系起来；以及(2)确定如何 抑制TgMyoA影响体内寄生虫的传播和疾病进展，以更好地了解其作用 TgMyoA和寄生虫在感染期间的运动性，并提供对TgMyoA马达的第一次直接评估 作为预防或治疗弓形虫病的药物靶点。 最近的技术进步为操纵和研究寄生虫创造了前所未有的机会 以一种真正综合的方式进行运动。该项目将在所有范围内利用这一机会- 从TgMyoA马达的生化和生物物理特性到寄生虫的运动特性 在模型3D细胞外基质内，与寄生虫在感染后传播和致病的能力有关 动物。因此，这些结果将大大增强我们对弓形虫如何移动的机械理解。 在寄主体内致病。因为TgMyoA对毒力是必不可少的，而且与 人肌球蛋白也是药物开发的潜在靶点；通过直接测试TgMyoA的可药性 在动物感染模型中，这项工作将有助于不断努力开发新的和改进的 控制艾滋病患者弓形虫感染的化疗药物。

Toxoplasmic encephalitis (TE) is a life-threatening infection of the brain in AIDS patients caused by the opportunistic pathogen, Toxoplasma gondii. Drugs are available to treat acute T. gondii infection in these patients, and to suppress its re-emergence in those who are chronically infected, but for many patients the adverse effects of the drugs are severe, resulting in their discontinuation. Thus, there is a need to develop new, better-tolerated drugs to treat AIDS-related TE. This, in turn, requires a better understanding of the biology of T. gondii and the mechanisms underlying its virulence, so that critical points of vulnerability in the parasite’s life cycle can be identified and targeted. The life cycle stage of T. gondii responsible for disease pathogenesis, the tachyzoite, is highly motile. Tachyzoite motility is required for host cell invasion, migration across biological barriers, and dissemination through host tissues. T. gondii MyosinA (TgMyoA) is an unconventional myosin motor protein that plays a central role in parasite motility, and tachyzoites lacking TgMyoA are completely avirulent. The overarching goals of this project are to advance our mechanistic understanding of tachyzoite motility and to test whether small molecules targeting the motility machinery can ameliorate disease in an animal model of infection. The Specific Aims are to: (1) Determine how altering specific aspects of TgMyoA motor function affects parasite motility, by characterizing how recently identified small-molecule inhibitors of the TgMyoA motor affect its biomechanical activity and connecting these changes in motor function to effects on parasite 3D motility; and (2) Determine how inhibiting TgMyoA impacts parasite dissemination and disease progression, in vivo, to better understand the role of TgMyoA and parasite motility during infection and to provide the first direct evaluation of the TgMyoA motor as a drug target for preventing or treating toxoplasmosis. Recent technological advances have created an unprecedented opportunity to manipulate and study parasite motility in a truly integrated way. This project will capitalize on that opportunity across the full range of scales – from the biochemical and biophysical properties of the TgMyoA motor, to the characteristics of parasite motility within a model 3D extracellular matrix, to the ability of parasites to disseminate and cause disease in infected animals. The results will therefore significantly enhance our mechanistic understanding of how T. gondii moves within its hosts to cause disease. Because TgMyoA is both essential for virulence and distinctly different from human myosins it is also a potential target for drug development; by directly testing the druggability of TgMyoA in an animal model of infection, this work will contribute to ongoing efforts to develop new and improved chemotherapeutics for managing T. gondii infections in AIDS patients.