Host glycosyltransferases in the glycosylation of Toxoplasma proteins

弓形虫蛋白糖基化中的宿主糖基转移酶

基本信息

批准号：
8451142
负责人：
ANTHONY P. SINAI
金额：
$ 18.56万
依托单位：
UNIVERSITY OF KENTUCKY
依托单位国家：
美国
项目类别：
财政年份：
2013
资助国家：
美国
起止时间：
2013-01-18 至 2014-12-31
项目状态：
已结题

来源：
https://reporter.nih.gov/project-details/8451142
关键词：
Acquired Immunodeficiency Syndrome Address Affinity Agglutinins Animals Antibodies Antigens Binding Biogenesis Bioinformatics Biological Assay Biology Blood Brain Cells Chinese Hamster Ovary Cell Competence Cross Presentation Cultured Cells Cyst Defect Detection Disease Dolichos Elements Endoplasmic Reticulum Enzymes Epitopes Event Exhibits Felis catus Funding Mechanisms Genes Genome Glycoproteins Golgi Apparatus Growth HIV Immune Immune response Immune system Immunosuppression Individual Infection Ingestion Integration Host Factors Label Lectin Life Light Link Maintenance Measures Mediating Membrane Modification Molecular Cloning Monoclonal Antibodies Muscle Oocysts Organelles Parasites Pathogenesis Pathway interactions Patients Pattern Peanut Agglutinin Polysaccharides Protein Glycosylation Proteins Recruitment Activity Reporter Research Design Risk Role Sambucus nigra Sialic Acids Sialyltransferases Small Interfering RNA Spatial Distribution Specificity Staining method Stains Sterility System Testing Tissues Toxoplasma Toxoplasma gondii Toxoplasmosis Vacuole Vesicle Viral Tumor Antigens Work base clinically relevant glycosylation glycosyltransferase innovation jacalin microbial mutant novel parasite genome pathogen prevent public health relevance sialylation success sugar tissue culture transmission process

项目摘要

DESCRIPTION (provided by applicant): The protozoan parasite Toxoplasma gondii is an important infection causing life threatening disease in patients with HIV-AIDs and other immune suppressive conditions. Despite the activation of a robust immune response including high antibody titers in infected individuals, sterile cure is not achieved. Rather the parasite differentiates into a relatively metabolically quiescent tissue cyst form. Tissue cysts which establish within muscle and the CNS, are characterized by having a highly glycosylated cyst wall and matrix. A given cyst may contain several hundred individual parasites. Our studies using lectin reactivity have identified the presence of sialic acid containing glycans in the tissu cyst wall and matrix of both brain derived and tissue culture induced cysts. This finding is remarkable in light of the absence of any of the machinery for the synthesis, activation and transfer of sialic acid being found in the parasite genome. The implication of this finding is that host activities may be responsible for the sialylation of the tissue cyst associated glycans. In ths study we explore this radical hypothesis by using established host cell mutants with defects in distinct steps of the sialylation pathway to confirm the contribution of the host cell. In addition specific host activities will also be targeted using siRNA knockdowns to establish the classes of sialyltransferases involved. Finally we will develop as split GFP/Luc based system to address whether fusion of the parasitophorous vacuole membrane and the associated ER as well as the redirection of Golgi associated vesicles is involved in the delivery of cyst modifying glycosylatin enzymes from the host cell. We believe that by hijacking the host's own glycosylation machinery, the parasite may avoid detection by the immune system by effectively "sugar coating" potentially antigenic determinants with "self" sugars rendering them functionally invisible.

描述（由申请人提供）：原生动物寄生虫弓形虫弓形虫是一种重要的感染，导致HIV-AID和其他免疫抑制疾病的患者造成生命危险。尽管激活了强大的免疫反应，包括感染个体中的高抗体滴度，但尚未实现无菌治疗。而是寄生虫分化为相对代谢静止的组织囊肿形式。在肌肉和中枢神经系统内建立的组织囊肿的特征是具有高度糖基化的囊肿壁和基质。给定的囊肿可能包含数百个单独的寄生虫。我们使用凝集素反应性的研究确定了在组织囊肿壁中含有聚糖的唾液酸的存在以及脑衍生和组织培养诱导的囊肿的基质。鉴于没有任何用于在寄生虫基因组中发现的唾液酸的合成，激活和转移的机械，这一发现是显着的。这一发现的含义是宿主活动可能是导致组织囊肿相关聚糖的溶解作用的原因。在THS研究中，我们通过在囊lylation途径的不同步骤中使用已建立的宿主细胞突变体探讨了这一自由基假设，以确认宿主细胞的贡献。此外，还将使用siRNA敲低的特定宿主活动来建立涉及的乙烯基转移酶类别。最后，我们将作为基于GFP/LUC的分裂系统开发，以解决寄生虫液泡膜和相关的ER的融合以及Golgi相关囊泡的重定向是否与从宿主细胞中修饰糖基质蛋白酶的囊肿递送有关。我们认为，通过劫持宿主自己的糖基化机制，寄生虫可以通过有效地“糖涂层”使用“自我”糖使其在功能上看不见的“自我”糖来避免被免疫系统检测。