Costimulatory ligand mobility effects on T cell activation

共刺激配体迁移率对 T 细胞激活的影响

• 批准号: 8841379
• 负责人: Janis K. Burkhardt
• 金额: $ 33.27万
• 依托单位: CHILDREN'S HOSP OF PHILADELPHIA
• 依托单位国家: 美国
• 财政年份: 2013
• 资助国家: 美国
• 起止时间: 2013-07-01 至 2016-04-30
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8841379
• 关键词: Actin-Binding Protein; Actinin; Actins; Adoptive Transfer; Affect; Antibodies; Antigen-Presenting Cells; Antigens; Autoimmune Diseases; Automobile Driving; Binding; Biochemical; Biological Assay; CD80 gene; Cell membrane; Cells; Clinical; Collaborations; Complex; Cytoplasmic Tail; Cytoskeleton; Dendritic Cells; Development; Diffusion; Engineering; Equilibrium; Event; Exhibits; Fluorescence Recovery After Photobleaching; Health; Hypersensitivity; Immune response; Immunity; In Vitro; Intercellular adhesion molecule 1; Interleukin-2; Knowledge; Label; Lateral; Ligands; Lipid Bilayers; Mass Spectrum Analysis; Measures; Mediating; Membrane; Modeling; Molecular; Molecular Conformation; Monitor; Movement; Mutate; Natural Killer Cells; Nature; Patients; Pattern; Peptide/MHC Complex; Peptides; Play; Printing; Process; Production; Protein Binding; Role; Shapes; Side; Signal Transduction; Signaling Molecule; Structure; Surface; Synapses; T cell response; T-Cell Activation; T-Cell Proliferation; T-Lymphocyte; TCR Activation; Tail; Testing; Transplant Recipients; Tyrosine Phosphorylation; Vaccines; adaptive immunity; base; biophysical techniques; copolymer; immunological synapse; in vivo; inhibitor/antagonist; insight; intercellular cell adhesion molecule; intravital imaging; moesin; mutant; nanolithography; nanoscale; novel; receptor; research study; response; surface coating; therapeutic target; transplantation medicine; vaccine development

DESCRIPTION (provided by applicant): Costimulatory signals lower the threshold for T cell activation, and tune the immune response, driving T cells towards distinct effector lineages and establishing the balance between immunity and tolerance. Because of their central role in shaping the immune response, and because of the conserved nature of costimulatory receptor-ligand interactions, costimulatory molecules are powerful therapeutic targets. Interaction of T cells with pMHC and costimulatory ligands such CD80/86 and ICAM-1 takes place at the immunological synapse. Several pieces of evidence suggest that the DC cytoskeleton plays an important role in modulating signaling events at the immunological synapse, but the molecular basis for this is not understood. We have discovered that while pMHC moves relatively freely on the DC membrane, the DC actin cytoskeleton constrains the mobility of ICAM-1 and CD80, and we have identified two actin-binding proteins, moesin and ¿-actinin, that play a key role in this process. We hypothesize that cytoskeletal constraints to mobility of ICAM-1 and CD80 on the DC surface promote costimulatory signaling, by creating tension on receptors and modulating dynamics of signaling microclusters on the T cell side of the synapse. This hypothesis will be tested by carrying out three specific aims. First, we will characterize the interactions of moesin and ¿- actinin with basic sequences in the cytoplasmic tails of ICAM-1 and CD80, and test the effects of perturbing these interactions on lateral diffusion of ICAM-1 and CD80. Second, in collaboration with membrane biophysicist Tobias Baumgart, we will use novel mixed mobility surfaces to test the effects of varying ICAM-1 mobility and patterning while maintaining pMHC in a mobile state. Several aspects of the T cell response to these surfaces will be assessed, including specific signaling events, LFA-1 conformational change, and dynamics of the T cell cytoskeleton and associated signaling molecules. Finally, we will engineer DCs in which ICAM-1 mobility is altered, either by perturbing actin-binding proteins or by mutating interacting residue in the ICAM-1 tail, and test the effects on T cell activation and lineage development in vitro. Adoptive transfer experiments will also be performed to test the effects of ICAM-1 mobility on T cell-DC interactions in vivo using intravital imaging. Taken together, these studies will test an unexplored aspect of costimulatory signaling, and will provide important new insights into how the DC actin cytoskeleton modulates the immune response. This information will guide clinical efforts to manipulate DC function in vaccine development, transplantation medicine and treatment of allergy and autoimmune disease.

描述（由申请人提供）：共刺激信号降低 T 细胞激活的阈值，并调节免疫反应，驱动 T 细胞走向不同的效应谱系，并建立免疫和耐受之间的平衡。由于它们在形成免疫反应中的核心作用，并且由于共刺激受体-配体相互作用的保守性质，共刺激分子是强大的治疗靶点。 T 细胞与 pMHC 和共刺激配体（例如 CD80/86 和 ICAM-1）的相互作用发生在免疫突触处。一些证据表明 DC 细胞骨架在调节免疫突触信号事件中发挥着重要作用，但其分子基础尚不清楚。我们发现，虽然 pMHC 在 DC 膜上相对自由地移动，但 DC 肌动蛋白细胞骨架限制了 ICAM-1 和 CD80 的移动性，并且我们鉴定了两种肌动蛋白结合蛋白，moesin 和 ¿-actinin，它们在此过程中发挥着关键作用。我们假设细胞骨架对 DC 表面 ICAM-1 和 CD80 移动性的限制通过在受体上产生张力并调节突触 T 细胞侧信号微簇的动态来促进共刺激信号传导。该假设将通过实现三个具体目标来检验。首先，我们将表征 moesin 和 ¿-肌动蛋白与 ICAM-1 和 CD80 细胞质尾部基本序列的相互作用，并测试干扰这些相互作用对 ICAM-1 和 CD80 横向扩散的影响。其次，我们将与膜生物物理学家 Tobias Baumgart 合作，使用新型混合迁移表面来测试不同 ICAM-1 迁移率和图案的影响，同时保持 pMHC 处于移动状态。将评估 T 细胞对这些表面的反应的几个方面，包括特定信号事件、LFA-1 构象变化以及 T 细胞细胞骨架和相关信号分子的动态。最后，我们将通过扰乱肌动蛋白结合蛋白或通过突变 ICAM-1 尾部的相互作用残基来改造 ICAM-1 流动性被改变的 DC，并在体外测试对 T 细胞活化和谱系发育的影响。还将进行过继转移实验，以使用活体成像来测试 ICAM-1 流动性对体内 T 细胞-DC 相互作用的影响。总而言之，这些研究将测试共刺激信号传导的一个未探索的方面，并将为 DC 肌动蛋白细胞骨架如何调节免疫反应提供重要的新见解。这些信息将指导在疫苗开发、移植医学以及过敏和自身免疫性疾病治疗中操纵 DC 功能的临床工作。