Microsporidia: invasion apparatus

摘要微孢子虫是一种与真菌有关的胞内病原体， 超过150年。它们是艾滋病患者的机会致病菌，最常见的是引起腹泻， 脑炎、肌炎或结膜炎。在晚期艾滋病患者中，高达30%的患者为病因 慢性腹泻伴消瘦的病例。微孢子虫也被发现引起其他 免疫功能低下的宿主，如经历过器官移植的患者或免疫功能低下的患者。 调节疗法。感染现在也在免疫能力强的宿主中被识别， 角膜结膜炎或腹泻。微孢子虫被归类为NIH B类优先病原体，EPA 病原体的利益，因为他们通过食物和水源传播。除了作为人类 病原体，这些病原体生物对农业具有重大的经济影响（通过对昆虫的影响 养殖业和畜牧业（食用、家养和野生动物）。动物感染的范围从 从隐蔽的良性感染到壮观的大规模感染，这些感染会造成广泛的损害， 主持人微孢子虫产生的孢子含有一种独特的入侵细胞器，极管，这是一个 最复杂的单细胞形式的一部分。极地的机制 tube在入侵过程中与宿主细胞的相互作用仍然是未知的。一个长期的研究项目在我的 实验组的重点是了解入侵机制和结构生物学， Polar Tube的组成。我们已经开发了纯化这种结构的技术， 极性管蛋白（PTP）及其翻译后修饰，并确定了研究这些修饰的方法。 蛋白质相互作用。此外，我们的研究已经确定了入侵突触和功能作用（S） 在入侵过程中的几个PTP。然而，这种结构中的全部蛋白质和 这些成分在入侵期间的相互作用仍有待确定。这项研究经费将用于 结合蛋白质组学、免疫学和超微结构研究来表征极管及其 蛋白质相互作用组，以更好地定义和理解入侵的机制。此外，先进 将采用显微镜技术（即冷冻电镜和超分辨率显微镜）来提供洞察力 进入到三维结构的极管和安排的PTP提供关键信息 关于这种入侵细胞器的组织的基本问题， 用传统的显微镜就能分辨出来。在其他微生物中，关于入侵的研究为 了解发病机制和新的治疗方法来管理感染。我们有 已经证明了各种PTP的抗血清可以抑制侵袭和感染。我们相信研究 对这种细胞器在萌发和入侵过程中的组成、形成和功能的研究， 为制定控制这些重要的艾滋病毒相关病原体的新战略奠定了基础。

ABSTRACT Microsporidia are intracellular pathogens related to the Fungi that have been studied for more than 150 years. They are opportunistic pathogens in patients with AIDS, most commonly causing diarrhea, encephalitis, myositis, or conjunctivitis. In patients with advanced AIDS they have been etiologic in up to 30% of cases of chronic diarrhea with wasting. Microsporidia have also been found to cause infections in other immunocompromised hosts, such as patients who have undergone organ transplantation or those on immune modulating therapies. Infections are now also being recognized in immune competent hosts causing either keratoconjunctivitis or diarrhea. Microsporidia are classified as NIH category B priority pathogens and EPA pathogens of interest as they are transmitted by both food and water sources. In addition to being human pathogens, these pathogenic organisms have major economic impacts on agriculture (via effects on insects and sericulture), aquaculture and animals (food, domestic and wildlife). Infections in animals range from cryptic, benign infections to spectacular, massive infections that cause extensive damage and often death of the host. Microsporidia produce spores containing a unique invasion organelle, the polar tube, which is one of the most complex single celled forms known in the biological world. The mechanism by which the polar tube interacts with its host cell during invasion is still unknown. A long standing research program in my laboratory group is focused on understanding the mechanism of invasion and the structural biology and composition of the polar tube. We have developed techniques for the purification of this structure, identified polar tube proteins (PTPs) and their post translational modifications, and defined methods to study how these proteins interact. Furthermore, our investigations have defined the invasion synapse and the functional role(s) of several PTPs in the process of invasion. However, the full complement of proteins in this structure and the interactions of these components during invasion remain to be determined. This research grant will employ a combination of proteomic, immunologic and ultrastructural studies to characterize the polar tube and its protein interactome to better define and understand the mechanism of invasion. Furthermore, advanced microscopic techniques (i.e. cryo-EM and super resolution microscopy) will be employed to provide insight into the three dimensional structure of the polar tube and arrangement of PTPs providing critical information on fundamental questions concerning the organization of this invasion organelle that have not been able to be resolved by traditional microscopy. In other microbes studies on invasion have provided critical data for understanding pathogenesis and for new therapeutic approaches to the management of infections. We have already demonstrated that antisera to various PTPs can inhibit invasion and infection. We believe that studies of the composition, formation and function of this organelle during germination and invasion should provide a basis for the development of new strategies for control of these important HIV-associated pathogens.