HS1 Function in Dendritic Cells

描述（由申请人提供）：树突状细胞（DC）通过收集外周组织中的病原体和肿瘤细胞碎片，并将其作为肽递送至淋巴结以呈递给T细胞，在免疫应答中发挥关键作用。DC功能严重依赖于肌动蛋白细胞骨架，肌动蛋白调节蛋白如WASp的突变导致与免疫缺陷和自身免疫相关的DC功能缺陷。在T细胞中，我们先前表明WASp与另一种肌动蛋白调节蛋白HS 1一起工作。HS 1也在树突状细胞中表达，我们的初步数据表明，HS 1是有效的抗原呈递所必需的。此外，我们发现，HS 1是所需的组织的podosomes，结构所需的粘附细胞外基质和基质金属蛋白酶沉积在细胞迁移通过组织。我们假设HS 1与DCs中的WASp和发动蛋白II一起作用，控制受体介导的内吞作用和依赖于podosome的向淋巴器官的迁移。为了验证这个假设，我们将实现三个目标。首先，我们将测试HS 1与发动蛋白II的相互作用在受体介导的内吞过程中驱动囊泡内化的作用，并询问HS 1是否也需要额外的步骤，细胞内运输和处理内化的抗原。第二，我们将调查lamellipodial和podosome动态迁移BMDCs使用视频显微镜，问HS 1是否需要分泌基质金属蛋白酶，并测试HS 1-/-DC迁移到淋巴结的能力在体内。第三，我们将进行结构-功能的研究，以测试的假设，即HS 1的C-末端SH 3结构域指导其肌动蛋白的调节功能，通过调节WASp和动力蛋白II的相互作用，在内吞和迁移。综上所述，这些研究将代表第一次仔细分析HS 1功能的树突状细胞，并将提供重要的新见解肌动蛋白调控途径如何控制特定方面的DC功能。这些信息将是有价值的发展免疫缺陷和自身免疫性疾病的治疗策略，由于肌动蛋白调节蛋白的突变，并为有效的DC为基础的疫苗和免疫疗法的发展。 公共卫生相关性：树突状细胞功能的几个方面依赖于细胞结构的高度协调变化，关键细胞骨架调节蛋白的突变导致严重的免疫缺陷或狼疮。这个建议解决了一个重要的细胞骨架调节蛋白，HS 1，在树突状细胞功能的特定方面的作用。从这些研究中获得的知识对于理解免疫缺陷和自身免疫性疾病的基础以及开发有效的树突状细胞疫苗将是重要的。

DESCRIPTION (provided by applicant): Dendritic cells (DCs) play a pivotal role in the immune response, by collecting pathogens and tumor cell debris in peripheral tissues, and delivering these as peptides to lymph nodes for presentation to T cells. DC function relies heavily on the actin cytoskeleton, and mutations in actin-regulatory proteins like WASp lead to defects in DC function associated with immunodeficiency and autoimmunity. In T cells, we showed previously that WASp works together with another actin regulatory protein, HS1. HS1 is also expressed in dendritic cells, and our preliminary data show that HS1 is required for efficient antigen presentation. In addition, we find that HS1 is required for organization of podosomes, structures required for adhesion to the extracellular matrix and matrix metalloproteinase deposition during cell migration through tissues. We hypothesize that HS1 works together with WASp and dynamin II in DCs, to control receptor-mediated endocytosis and podosome- dependent migration to lymphoid organs. To test this hypothesis, we will carry out three Aims. First, we will test the role of HS1 interactions with dynamin II in driving vesicle internalization during receptor-mediated endocytosis, and ask if HS1 is also required for additional steps the intracellular transport and processing of internalized antigens. Second, we will investigate lamellipodial and podosome dynamics in migrating BMDCs using video microscopy, ask if HS1 is required for secretion of matrix metalloproteinases, and test the ability of HS1-/- DCs to migrate to lymph nodes in vivo. Third, we will conduct structure-function studies to test the hypothesis that the C-terminal SH3 domain of HS1 directs its actin-regulatory functions during endocytosis and migration via regulated interactions with WASp and dynamin II. Taken together, these studies will represent the first careful analysis of HS1 function in dendritic cells, and will provide important new insights into how actin regulatory pathways control specific aspects of DC function. This information will be valuable for developing therapeutic strategies for immunodeficiency and autoimmune diseases that arise as a result of mutations in actin-regulatory proteins, and for the development of effective DC-based vaccines and immunotherapies. PUBLIC HEALTH RELEVANCE: Several aspects of dendritic cell function depend on highly orchestrated changes in cell structure, and mutations in key cytoskeletal regulatory proteins lead to severe immunodeficiency or Lupus. This proposal addresses the role of one important cytoskeletal regulatory protein, HS1, in specific aspects of dendritic cell function. The knowledge gained from these studies will be important for understanding the basis of immunodeficiency and autoimmune disease, and for the development of effective dendritic cell-based vaccines.