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弓形虫在免疫抑制或移植患者。它的病理主要依赖于从感染部位传播寄生虫各种必需器官，例如大脑，会导致组织破坏。 T. Gondii经常使用特洛伊木马马匹机制促进其传播，在此期间，它劫持了宿主细胞迁移机制选择主机白细胞作为穿梭媒介。然而，T。Gondii的目的是在很大程度上尚不清楚。我们最近确定了一种新颖的gondii蛋白对于其传播很重要，我们将其命名为TGWIP。我们发现入侵后，寄生虫将TGWIP分泌到宿主细胞胞质中，TGWIP刺激了树突状细胞成为过度迁移的，并经历间充质到变形虫过渡（MAT）。该过程是与肌动蛋白细胞骨架的戏剧性重排有关。该应用程序的总体目标是为了确定TGWIP介导宿主中T. gondii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。这根据我们的初步数据提出了假设，表明TGWIP直接与几种相互作用与细胞迁移有关的肌动蛋白细胞骨架的中心调节剂，包括波调节复合物（WRC），SH2-SH3适配器蛋白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假设：1）确定TGWIP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，2）确定TGWIP如何增强宿主白细胞运动以促进体内传播。具体而言，我们的团队将将生物化学，细胞生物学和动物模型结合起来确定（i）TGWIP如何直接与WRC，NCK，GRB2和SHP1/2相互作用，以及如何相互作用在体外影响肌动蛋白聚合；（ii）这些相互作用如何改变主要的迁移行为树突状细胞；（iii）这些相互作用的破坏如何影响小鼠gondii的体内传播。我们提出的研究具有创新性，因为它将揭示出一种新型机制鉴定出T. gondii独有的寄生虫效应子，协调了几个不同的宿主肌动蛋白调节剂以重新布局白细胞迁移并促进了弓形虫的传播。我们的工作很重要，因为了解 T. gondii传播基础的分子和生化机制将为开发新的干预措施，这些干预措施可以直接瞄准这些机制并阻止T. gondii 急性感染或艾滋病患者或从母亲到胎儿的急性感染或重新激活后的传播。这些知识对于开发安全的，不可允许的活疫苗也将很重要防止弓形虫从动物中传播。此外，通过了解TGWIP如何促进MAT 感染的DC，我们的工作将为其他细胞（例如转移性癌细胞和）如何提供宝贵的见解。白细胞可能会使用类似的机制来响应各种环境条件。