Composition and formation of the cyst wall

囊肿壁的组成和形成

• 批准号: 9593710
• 负责人: Louis M. Weiss
• 金额: $ 18.9万
• 依托单位: ALBERT EINSTEIN COLLEGE OF MEDICINE, INC
• 依托单位国家: 美国
• 财政年份: 2018
• 资助国家: 美国
• 起止时间: 2018-06-01 至 2018-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/9593710
• 关键词: Acetylgalactosamine; Acquired Immunodeficiency Syndrome; Animals; Antibody titer measurement; Appearance; Area; Biogenesis; Birds; Brain; Bypass; Cells; Chorioretinitis; Chronic; Cyst; Development; Developmental Biology; Disease; Dolichos; Encephalitis; Equilibrium; Eye; Feces; Felis catus; Food Contamination; Genes; Genetic Techniques; Glycoproteins; Goals; Human; Immune; Immune response; Immune system; Immunocompromised Host; Immunologic Techniques; Impairment; Individual; Infection; Ingestion; Investigation; Knock-out; Label; Laboratories; Lectin; Life Cycle Stages; Longitudinal Studies; Mammals; Mediating; Membrane; Mental Retardation; Methods; Modeling; Morbidity - disease rate; Morphology; Mucins; Mus; Neuraxis; Neurons; Oocysts; Opportunistic Infections; Oral; Organ Transplantation; Organism; Parasites; Pathogenicity; Patients; Pharmaceutical Preparations; Post-Translational Protein Processing; Proteins; Proteome; Proteomics; Publications; Reagent; Recurrence; Reproducibility; Research; Role; Rupture; Scaffolding Protein; Sporozoites; Stress; Structural Protein; Structure; Techniques; Therapeutic Agents; Thick; Time; Tissues; Toxoplasma gondii; Toxoplasmosis; Vacuole; acute infection; animal tissue; asexual; chronic infection; congenital infection; contaminated water; glycosylation; improved; in utero; latent infection; novel strategies; pathogen; prevent; public health relevance; succinylated wheat germ agglutinin; therapeutic development; transmission process; vaccine development

ABSTRACT: Toxoplasma gondii is a ubiquitous Apicomplexan protozoan parasite of mammals and birds. It is unusual in that propagation does not require passage through its definitive host enabling T. gondii to propagate clonally through its intermediate hosts. T. gondii causes congenital infections in immune competent hosts and opportunistic infections in immune compromised hosts. The predilection of this parasite for the central nervous system causing necrotizing encephalitis and for the eye causing chorioretinitis constitutes its major threat to patients. The development of these diseases is a consequence of the transition of bradyzoites, found within tissue cysts into actively replicating tachyzoites. It is believed that tissue cysts are not static structures, but regularly rupture reinvading new host cells. It is likely that in chronic toxoplasmosis, i.e. latent infection, tissue cysts within host cells, regularly transform to tachyzoites which are removed or sequestered by the immune system. Degenerating cysts are often seen in the brains of mice with chronic toxoplasmosis. Such a dynamic equilibrium between encysted and replicating forms leads to recurrent antigenic stimulation and the persistent antibody titers found in chronically infected hosts. The widespread distribution of T. gondii in humans and other animals is due to the ability of tissue cysts to permit oral transmission of this infection. The cyst wall is the critical structure for survival, reactivation and transmission of T. gondii. Understanding T. gondii developmental biology and formation of the cyst wall will inform strategies such as vaccine development and therapeutic agents to eliminate latency and prevent reactivation toxoplasmosis. Several lines of evidence suggest that bradyzoite differentiation is stress mediated and that the cyst wall (a modified parasitophorous vacuole membrane) contains many stage specific proteins and glycoproteins. Our laboratory group has identified several cyst wall specific proteins several of which have mucin type domains that are o-glycosylated and demonstrated that glycosylation is important for cyst wall stability. CST1, a cyst wall glycoprotein, appears to be a scaffolding protein for formation of the cyst wall and we hypothesize that other cyst wall proteins interact with CST1 in establishing the cyst wall. Our laboratory group has developed techniques to purify the cyst wall enabling proteomic characterization of this structure as well as adapted BirA tagging techniques to enable definition of the cyst wall interactome. Furthermore, we have established ppGalNAcTs knockout T. gondii strains that enable studies on the role of o-glycosylation in cyst wall formation. An integrated approach employing proteomic, immunologic and genetic techniques will be used to fully characterize the T. gondii cyst wall proteome and the importance and interactions of the identified cyst wall components. The improved understanding of the formation of the cyst wall provide by these studies will provide the basic underpinnings of new strategies to eliminate latent infection thereby preventing reactivation toxoplasmosis.

摘要：弓形虫Gondii是哺乳动物和 鸟类。这是不寻常的，因为传播不需要通过其确定的主机实现T的通道。 Gondii通过其中间宿主在克隆中传播。 T. gondii引起先天性感染 免疫托管宿主和机会感染免疫受损的宿主。偏见 中枢神经系统的这种寄生虫导致坏死性脑炎和眼睛引起的眼睛 脉络膜结构炎构成其对患者的主要威胁。这些疾病的发展是 在组织囊肿内发现的Bradyzoites过渡的结果 tachyzoites。人们认为组织囊肿不是静态结构，而是经常破裂的新型 宿主细胞。在慢性弓形虫病，即潜在感染，宿主细胞内的组织囊肿，很可能很可能 定期转化为被免疫系统去除或隔离的tachyzoites。 在患有慢性弓形虫病的小鼠的大脑中经常看到退化的囊肿。这样的动态 环境和复制形式之间的平衡导致复发性抗原刺激，并导致 在长期感染的宿主中发现的持续性抗体滴度。 T. gondii的广泛分布 人类和其他动物是由于组织囊肿允许口服这种感染的能力。 囊肿壁是T. gondii生存，重新激活和传播的临界结构。 了解T. gondii发育生物学和囊肿墙的形成将为此类策略提供信息 作为疫苗发育和治疗剂，以消除潜伏期并防止重新激活 弓形虫病。有几条证据表明，布拉迪二核分化是应力介导的 并且囊肿壁（修饰的寄生虫液泡膜）包含许多阶段的特异性 蛋白质和糖蛋白。我们的实验室组已经确定了多个囊肿壁特异性蛋白 其中几个具有O-糖基化的粘蛋白型结构域，并证明 糖基化对于囊肿壁稳定性很重要。 CST1是囊壁糖蛋白，似乎是 脚手架蛋白用于形成囊肿壁，我们假设其他囊肿壁蛋白 在建立囊壁时与CST1相互作用。我们的实验室小组开发了技术 净化囊肿壁，以实现该结构的蛋白质组学表征以及改编的Bira 标记技术可以启用囊肿壁相互作用的定义。此外，我们还有 已建立的pPGALNACTS基因敲除T. gondii菌株，可以研究O-糖基化的作用 在囊壁形成中。采用蛋白质组学，免疫和遗传的综合方法 技术将用于充分表征T. gondii囊肿壁蛋白质组和重要性和 已鉴定的囊肿壁成分的相互作用。对形成的理解有了改善 这些研究提供的囊肿墙将为新策略提供基本的基础 消除潜在感染，从而防止重新激活毒质量。