Cytoskeletal control of Leishmania infection

利什曼原虫感染的细胞骨架控制

• 批准号: 8125461
• 负责人: Dawn Marie Wetzel
• 金额: $ 5.73万
• 依托单位: YALE UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-04-01 至 2013-06-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8125461
• 关键词: Actins; Address; Adhesions; Antiparasitic Agents; Binding; Biochemical; Biochemical Pathway; Biological Assay; Bite; Cell Lineage; Cell Surface Receptors; Cell surface; Cells; Cellular Structures; Cessation of life; Chemicals; Complex; Cytoskeleton; Data; Defect; Development; Disease; Drug Delivery Systems; Event; Family; Fibroblasts; Fibronectins; Genes; Gleevec; Hematopoietic; Homologous Gene; Human; Imatinib; In Vitro; Infection; Integrin Binding; Integrins; Knockout Mice; Knowledge; Laboratories; Lead; Leishmania; Leishmaniasis; Life; Life Cycle Stages; Link; Mediating; Membrane; Molecular Biology Techniques; Mus; Parasites; Parasitic infection; Pathogenesis; Pathway interactions; Phagocytosis; Pharmaceutical Preparations; Phosphorylation; Phosphotransferases; Predisposition; Preparation; Process; Protein Kinase; Protein Tyrosine Kinase; Proteins; Research; Resistance development; Sand Flies; Signal Pathway; Signal Transduction; Skin Ulcer; Swelling; System; Testing; Translating; Visceral; Work; base; cell motility; extracellular; human EMS1 protein; improved; in vivo; inhibitor/antagonist; killings; leukemia; macrophage; mouse model; novel; parasite invasion; polymerization; receptor; research study; surface coating; uptake

DESCRIPTION (provided by applicant): Leishmania is a parasite that causes severe skin ulcers or visceral disease in people living in the developing world. Every year, it infects millions of people, and kills over 50,000. Drugs for treating infection by Leishmania are very toxic, and the parasite is developing resistance to them. For these reasons, new drugs are needed to treat infections by this parasite. Leishmania must live inside macrophages to survive in and cause disease within a host. To enter macrophages, Leishmania binds to integrin receptors on the cell surface. The parasite then triggers its own uptake through the process of phagocytosis. The mechanisms that permit cell entry by Leishmania are not well understood. This project aims to characterize the signaling events that translate the binding of cell surface receptors to the reorganization of the cytoskeleton, which is required for internalization of Leishmania. Understanding the mechanisms of cell entry by Leishmania will help explain how this parasite causes disease. Furthermore, if one could disrupt the pathways that lead to invasion of macrophages by Leishmania, the parasite should not be able to survive within a host to cause disease. Therefore, these studies may also suggest new drugs to treat this parasitic infection. Abl family kinases are proteins that transfer signals from extracellular integrin receptors to the cytoskeleton in order to orchestrate cell movement. These kinases are known to activate cortactin, which triggers actin-based cell edge protrusions. HS1 (hematopoietic lineage cell-specific protein 1) is a protein related to cortactin that is found in macrophages. Preliminary work in the laboratory demonstrates that signals from cell surface receptors activate Abl family kinases and stimulate phagocytosis. However, signaling pathways requiring Abl family kinases or HS1 have not been linked to uptake of Leishmania by macrophages. The central hypothesis in this proposal is that Leishmania uses a signaling pathway that requires integrin receptors, Abl family kinases, and HS1 to enter cells and cause disease. Specific Aim 1 addresses whether Abl family kinases mediate cell entry and infection by Leishmania, and if 22 integrins directly bind and activate Abl family kinases. Specific Aim 2 addresses whether Leishmania requires HS1 signaling for cell entry and infection; it also tests whether Abl family kinases activate HS1. In both specific aims, macrophages will be infected with Leishmania to understand the requirement for each of these signaling components for cell entry, and mice will be infected with Leishmania to determine the significance of these proteins in disease. Biochemical assays with purified proteins and molecular biology techniques to disrupt interactions between proteins will also be employed to elucidate the interfaces between key components in this signaling pathway. By identifying whether signaling though integrins, Abl family kinases, and HS1 allows Leishmania to enter cells and cause disease in mice, our understanding of the process of Leishmania infection will improve. PUBLIC HEALTH RELEVANCE: This project seeks to explain how a human parasite called Leishmania gains entry into cells in order to survive. Leishmania infects millions of people every year worldwide, and kills more than 50,000 of them. We hope that if we understand how Leishmania enters cells, new drugs can be developed that block cell entry, and therefore, disease caused by this parasite.

描述(申请人提供)：利什曼原虫是一种寄生虫，在发展中国家的人们中会导致严重的皮肤溃疡或内脏疾病。每年，它感染数百万人，并导致超过5万人死亡。治疗利什曼原虫感染的药物毒性很大，这种寄生虫正在对它们产生抗药性。出于这些原因，需要新药来治疗这种寄生虫的感染。利什曼原虫必须生活在巨噬细胞内，才能在宿主体内生存并引发疾病。为了进入巨噬细胞，利什曼原虫与细胞表面的整合素受体结合。然后，寄生虫通过吞噬过程触发自己的摄取。利什曼原虫允许细胞进入的机制还不是很清楚。该项目旨在表征将细胞表面受体的结合转化为细胞骨架重组的信号事件，这是利什曼原虫内化所必需的。了解利什曼原虫进入细胞的机制将有助于解释这种寄生虫如何致病。此外，如果一个人能够破坏导致利什曼原虫入侵巨噬细胞的途径，这种寄生虫应该不能在宿主内存活而致病。因此，这些研究还可能提出治疗这种寄生虫感染的新药。ABL家族蛋白是一种将信号从细胞外整合素受体传递到细胞骨架以协调细胞运动的蛋白质。众所周知，这些激酶可以激活皮质蛋白，从而触发基于肌动蛋白的细胞边缘突起。HS1(造血系细胞特异性蛋白1)是一种与皮质蛋白相关的蛋白质，存在于巨噬细胞中。实验室的初步工作表明，来自细胞表面受体的信号激活Abl家族激酶并刺激吞噬作用。然而，需要Abl家族激酶或HS1的信号通路尚未与巨噬细胞摄取利什曼原虫有关。这一建议的中心假设是利什曼原虫使用一种信号通路，需要整合素受体、Ab1家族激酶和HS1进入细胞并导致疾病。具体目的1探讨Abl家族激酶是否介导利什曼原虫的细胞进入和感染，以及22整合素是否直接结合和激活Abl家族激酶。具体目标2解决利什曼原虫是否需要HS1信号才能进入细胞和感染；它还测试Abl家族激酶是否激活HS1。在这两个特定目标中，巨噬细胞将感染利什曼原虫，以了解这些信号成分中的每一个进入细胞的要求，小鼠将感染利什曼原虫，以确定这些蛋白质在疾病中的意义。使用纯化蛋白质的生化分析和破坏蛋白质之间相互作用的分子生物学技术也将被用来阐明这一信号通路中关键成分之间的接口。通过确定整合素、Abl家族激酶和HS1是否允许利什曼原虫进入细胞并在小鼠身上引起疾病，我们对利什曼原虫感染过程的理解将得到改善。 与公共卫生相关：这个项目试图解释一种名为利什曼原虫的人类寄生虫是如何进入细胞以生存的。全世界每年有数百万人感染利什曼原虫，其中超过5万人死亡。我们希望，如果我们了解利什曼原虫是如何进入细胞的，就可以开发出阻止细胞进入的新药，从而阻止这种寄生虫引起的疾病。