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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.

细胞内寄生虫刚地弓形虫在免疫抑制或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，如大脑，在那里它会导致组织破坏。T.弓形虫通常使用木马程序马机制，以促进其传播，在此期间，它劫持宿主细胞迁移机制，以共同- 选择宿主白细胞作为穿梭载体。如何T。然而，弓形虫的这种作用在很大程度上是未知的。我们最近发现了一种新的T.弓形虫的一种蛋白质，对它的传播很重要，我们将其命名为TgdR。我们发现在入侵时，寄生虫将Tgl分泌到宿主细胞胞质溶胶中，在那里Tgl刺激树突状细胞，细胞变得过度迁移并经历间充质向变形虫转变（MAT）。该过程与肌动蛋白细胞骨架的剧烈重排有关。本申请的总体目标是以确定Tgl介导T.弓形虫在宿主体内传播。我们中心假设是Tglutamine通过调节白细胞肌动蛋白动力学促进播散。这基于我们的初步数据，我们提出了一种假设，表明Tgl直接与几种参与细胞迁移的肌动蛋白细胞骨架的中枢调节因子，包括WAVE调节复合物 (WRC)SH 2-SH 3衔接蛋白Nck和Grb 2，以及SHP 1/2酪氨酸磷酸酶。我们将测试通过追求两个目标来实现这一假说：1）确定Tgl如何与各种肌动蛋白调节剂相互作用以调节体外宿主肌动蛋白动力学，和2）确定Tgl如何增强宿主白细胞运动，以促进体内传播。具体来说，我们的团队将联合收割机结合生物化学、细胞生物学和动物模型，确定（i）Tgal如何直接与WRC、Nck、Grb 2和SHP 1/2相互作用，以及这些相互作用如何与WRC、Nck、Grb 2和SHP 1/2相互作用。影响肌动蛋白聚合在体外;（ii）这些相互作用如何改变迁移行为的主要树突状细胞;以及（iii）这些相互作用的破坏如何影响T.小鼠弓形虫感染我们提出的研究是创新的，因为它将揭示一种新的机制，鉴定了T.弓形虫，协调几种不同的宿主肌动蛋白调节剂，白细胞迁移和促进T.弓形虫传播。我们的工作意义重大，因为了解 T.弓形虫的传播将为开发新的干预措施，可以直接针对这些机制和阻断T。弓形虫急性感染后的传播或艾滋病或移植患者的再激活或从母亲到胎儿。这些知识对于开发安全的、非传染性的活疫苗也很重要，预防T.从动物传播弓形虫。此外，通过了解Tgallet如何促进MAT，感染的DC，我们的工作将提供有价值的见解，了解其他细胞，如转移性癌细胞，白细胞可以使用类似的机制来响应于不同的环境条件而经历MAT。