Mechanisms of host leukocyte-mediated Toxoplasma dissemination in its host

宿主白细胞介导的弓形虫在宿主体内传播的机制

基本信息

批准号：
10623334
负责人：
Baoyu Chen
金额：
$ 46万
依托单位：
UNIVERSITY OF CALIFORNIA AT DAVIS
依托单位国家：
美国
项目类别：
财政年份：
2022
资助国家：
美国
起止时间：
2022-05-17 至 2027-04-30
项目状态：
未结题

来源：
https://reporter.nih.gov/project-details/10623334
关键词：
2-tyrosine Acquired Immunodeficiency Syndrome Actins Adaptor Signaling Protein Adhesives Affect Animal Model Animals Attenuated Vaccines Bar Codes Behavior Binding Biochemical Biochemistry Biological Assay Bioluminescence Blindness Brain CRISPR/Cas technology Cell-Matrix Junction Cells Cellular biology Cessation of life Co-Immunoprecipitations Complex Cytoskeleton Cytosol Data Defect Dendritic Cells Development Disease Disseminated Malignant Neoplasm Distant Equus caballus Exhibits Fetus Foundations Genes HIV Human body Image Immune Immune system Immunocompromised Host In Vitro Individual Infant Infection Intervention Knowledge Leukocytes Life Luciferases Measures Mediating Mesenchymal Molecular Mothers Mus NCK adaptor protein 1 NR0B2 gene Names Organ PTPN11 gene PTPN6 gene Parasites Pathology Pathway interactions Patients Peptides Persons Phosphoric Monoester Hydrolases Polymers Population Process Proline-Rich Domain Protein Kinase Protein Tyrosine Phosphatase Proteins Recombinants Regulation Research Route Shuttle Vectors Site Structure Testing Therapeutic Intervention Time Tissues Toxoplasma Toxoplasma gondii Toxoplasmosis Transplant Recipients Tyrosine Phosphorylation Vaccines Work acute infection cancer cell cell motility foodborne immunosuppressed in vivo innovation insight loss of function migration mutant novel novel therapeutics parasite invasion pathogen polymerization prevent protein protein interaction protein purification receptor response rho transmission process

项目摘要

The intracellular parasite Toxoplasma gondii causes life-threatening disease in immunosuppressed or transplant patients. Its pathology mainly relies on the dissemination of the parasite from the site of infection to various essential organs, such as the brain, where it causes tissue destruction. T. gondii often uses a Trojan Horse mechanism to facilitate its dissemination, during which it hijacks the host cell migration machinery to co- opt host leukocytes as shuttling vectors. Exactly how T. gondii does so, however, is largely unknown. We recently identified a novel T. gondii protein important for its dissemination, which we named TgWIP. We found that upon invasion the parasite secreted TgWIP into the host cell cytosol, where TgWIP stimulated dendritic cells to become hyper-migratory and undergo a mesenchymal to amoeboid transition (MAT). The process was associated with a dramatic rearrangement of the actin cytoskeleton. The overall objective of this application is to determine the molecular mechanisms by which TgWIP mediates T. gondii dissemination in the host. Our central hypothesis is that TgWIP promotes dissemination by modulating leukocyte actin dynamics. This hypothesis was formulated based on our preliminary data showing that TgWIP directly interacts with several central regulators of the actin cytoskeleton involved in cell migration, including the WAVE regulatory complex (WRC), the SH2-SH3 adaptor proteins Nck and Grb2, and the SHP1/2 tyrosine phosphatases. We will test our hypothesis by pursuing two aims: 1) determine how TgWIP interacts with various actin regulators to modulate host actin dynamics in vitro, and 2) determine how TgWIP enhances host leukocyte motility to facilitate dissemination in vivo. Specifically, our team will combine biochemistry, cell biology, and animal models to determine (i) how TgWIP directly interacts with the WRC, Nck, Grb2, and SHP1/2, and how the interactions influence actin polymerization in vitro; (ii) how these interactions alter the migrative behaviors of primary dendritic cells; and (iii) how disruption of these interactions influences in vivo dissemination of T. gondii in mice. Our proposed research is innovative because it will unravel a novel mechanism by which TgWIP, as a newly identified parasite effector unique to T. gondii, coordinates several distinct host actin regulators to reroute leucocyte migration and facilitate T. gondii dissemination. Our work is significant because understanding the molecular and biochemical mechanisms underlying T. gondii dissemination will lay the foundation for the development of novel interventions that can directly target these mechanisms and block T. gondii dissemination after acute infection or reactivation in AIDS or transplant patients or from the mother to the fetus. This knowledge will be also important for the development of a safe, non-transmissible live vaccine that can prevent T. gondii transmission from animals. Furthermore, by understanding how TgWIP promotes MAT in infected DCs, our work will provide valuable insights into how other cells, such as metastatic cancer cells and leukocytes, may use a similar mechanism to undergo MAT in response to diverse environmental conditions.

细胞内寄生虫弓形虫会在免疫抑制或免疫抑制的人群中引起危及生命的疾病移植患者。其病理学主要依赖于寄生虫从感染部位传播到各种重要器官，例如大脑，它会导致组织破坏。弓形虫经常使用木马马机制促进其传播，在此期间它劫持宿主细胞迁移机制来共同选择宿主白细胞作为穿梭载体。然而，弓形虫到底是如何做到这一点的，目前还不清楚。我们最近发现了一种对其传播很重要的新型弓形虫蛋白，我们将其命名为 TgWIP。我们发现入侵后，寄生虫将 TgWIP 分泌到宿主细胞胞浆中，其中 TgWIP 刺激树突细胞变得过度迁移并经历间充质向变形虫转变（MAT）。过程是与肌动蛋白细胞骨架的剧烈重排有关。该应用程序的总体目标是确定 TgWIP 介导弓形虫在宿主中传播的分子机制。我们的中心假设是 TgWIP 通过调节白细胞肌动蛋白动力学来促进传播。这我们的初步数据表明 TgWIP 直接与多种物质相互作用，从而制定了假设参与细胞迁移的肌动蛋白细胞骨架的中央调节因子，包括 WAVE 调节复合体 (WRC)、SH2-SH3 接头蛋白 Nck 和 Grb2 以及 SHP1/2 酪氨酸磷酸酶。我们将测试我们的通过追求两个目标来提出假设：1）确定 TgWIP 如何与各种肌动蛋白调节剂相互作用以进行调节体外宿主肌动蛋白动力学，2) 确定 TgWIP 如何增强宿主白细胞运动以促进体内传播。具体来说，我们的团队将结合生物化学、细胞生物学和动物模型来确定 (i) TgWIP 如何直接与 WRC、Nck、Grb2 和 SHP1/2 交互，以及如何交互影响体外肌动蛋白聚合； (ii) 这些相互作用如何改变初级物种的迁徙行为树突状细胞； (iii)这些相互作用的破坏如何影响弓形虫在小鼠体内的传播。我们提出的研究是创新的，因为它将揭示一种新的机制，通过该机制，TgWIP 作为一种新的确定了弓形虫特有的寄生虫效应子，协调几个不同的宿主肌动蛋白调节因子以重新路由白细胞迁移并促进弓形虫传播。我们的工作意义重大，因为了解弓形虫传播的分子和生化机制将为弓形虫传播奠定基础开发可以直接针对这些机制并阻断弓形虫的新型干预措施艾滋病或移植患者急性感染或重新激活后传播或从母亲传播到胎儿。这些知识对于开发一种安全的、非传染性的活疫苗也很重要。防止弓形虫从动物身上传播。此外，通过了解 TgWIP 如何促进 MAT 感染的树突状细胞，我们的工作将为了解其他细胞（例如转移性癌细胞）如何白细胞可能会使用类似的机制来经历 MAT 以响应不同的环境条件。