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：弓形虫是哺乳动物和哺乳动物中普遍存在的顶复门原生动物寄生虫。 鸟类。其不同寻常之处在于，传播不需要通过其最终宿主，从而使 T. 弓形虫通过其中间宿主进行克隆繁殖。弓形虫引起先天性感染 免疫能力强的宿主和免疫受损宿主的机会性感染。偏爱 这种寄生虫对中枢神经系统造成坏死性脑炎，对眼睛造成 脉络膜视网膜炎是其对患者的主要威胁。这些疾病的发生发展是 组织包囊内发现的缓殖子转变为活跃复制的结果 速殖子。据信，组织囊肿不是静态结构，而是定期破裂并重新侵入新的结构。 宿主细胞。在慢性弓形虫病中，即潜伏感染、宿主细胞内的组织囊肿， 定期转化为速殖子，并被免疫系统清除或隔离。 患有慢性弓形体病的小鼠大脑中经常会出现退化囊肿。这样的动态 包囊形式和复制形式之间的平衡导致反复的抗原刺激和 在慢性感染的宿主中发现持续的抗体滴度。弓形虫广泛分布于 人类和其他动物的组织包囊能力允许这种感染的口腔传播。 囊壁是弓形虫生存、重新激活和传播的关键结构。 了解弓形虫发育生物学和囊壁的形成将为诸如此类的策略提供信息 作为疫苗开发和治疗剂，以消除潜伏期并防止重新激活 弓形体病。多项证据表明缓殖子分化是应激介导的 并且囊壁（改良的寄生液泡膜）包含许多阶段特异性 蛋白质和糖蛋白。我们的实验室小组已经鉴定出几种囊壁特异性蛋白质 其中一些具有 o-糖基化的粘蛋白型结构域，并证明 糖基化对于囊肿壁的稳定性很重要。 CST1 是一种囊壁糖蛋白，似乎是 形成囊壁的支架蛋白，我们假设其他囊壁蛋白 与 CST1 相互作用建立囊肿壁。我们的实验室小组已经开发出技术 纯化囊壁，从而能够对该结构以及适应的 BirA 进行蛋白质组学表征 标记技术能够定义囊肿壁相互作用组。此外，我们还有 建立了 ppGalNAcTs 敲除弓形虫菌株，使研究 o-糖基化的作用成为可能 在囊肿壁的形成中。采用蛋白质组学、免疫学和遗传学的综合方法 技术将用于充分表征弓形虫包囊壁蛋白质组及其重要性和 已识别的囊肿壁成分的相互作用。加深对形成的认识 这些研究提供的囊肿壁将为新策略提供基本基础 消除潜伏感染，从而防止弓形虫病重新激活。