PlexinD1-regulated intrathymic movement

PlexinD1 调节的胸腺内运动

• 批准号: 8230513
• 负责人: Young Il Choi
• 金额: $ 15.86万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 财政年份: 2011
• 资助国家: 美国
• 起止时间: 2011-03-01 至 2013-02-28
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/8230513
• 关键词: Address; Adult; Architecture; Area; Autoimmune Process; Biological; Blood Circulation; Bone Marrow; CCL25 gene; CCR9 gene; CD8-Positive T-Lymphocytes; CD8B1 gene; CXCL12 gene; CXCR4 gene; Cardiovascular system; Cell Transplantation; Cell Transplants; Cell physiology; Cells; Cellular Immunity; Communicable Diseases; Complex; Data; Development; Event; Fetal Liver; Foundations; Generations; Genes; Hepatocyte; Immune system; Immunity; Implant; In Situ; Infectious Agent; Kidney; Knockout Mice; Lead; Life; Ligands; Link; Malignant Neoplasms; Mammalian Cell; Mature Thymocyte; Measures; Mediating; Microscopy; Molecular; Movement; Mus; Nervous system structure; Organ; Pathology; Pathway interactions; Peptide/MHC Complex; Peptides; Peripheral; Process; Proteins; Regulation; Regulatory Pathway; Research; Role; Scanning; Screening procedure; Semaphorins; Signal Pathway; Signal Transduction; Staging; Structure; Structure of thymic capsule; Surface; T-Cell Development; T-Cell Receptor; T-Lymphocyte; Thymic epithelial cell; Thymocyte Development; Thymus Gland; Time; Transgenic Mice; Transgenic Organisms; Transplantation; base; cell motility; cell type; chemokine; chemokine receptor; design; fetal; insight; internal control; liver transplantation; member; migration; multi-photon; plexin; programs; public health relevance; receptor; research study; response; thymocyte; trafficking; vaccine development

DESCRIPTION (provided by applicant): Thymocyte maturation and thymic architecture is dependent upon precise intrathymic cell migration. The orchestration of thymocyte trafficking, however, is not well understood at the molecular level. Recently, we described the highly-regulated plexinD1 expression on CD4+CD8+ double positive (DP) thymocytes which is further modified by T cell receptor/co-receptor engagement. Activation of plexinD1 via its ligand, semaphorin 3E (sema3E), represses CXCR4/CXCL12 signaling in pre-selection DP thymocytes and CCR9/CCL25 signaling in CD69+ post-selection DP thymocytes. Using Plxnd1-deficient fetal liver cell-transplanted mice, loss of plexinD1 causes CD69+ thymocytes to remain in the cortex, maturing in situ to form ectopic single positive (SP) thymocyte clusters. As a consequence, the boundary between DP and SP thymocytes at corticomedullary junctions is disrupted and medullary structures form under the thymic capsule. These results demonstrate the importance of plexinD1 in directing migration of maturing thymocytes via modulation of biological responses to chemokine gradients. The dysmorphic corticomedullary structures observed in Plxnd1-/- and Sema3e-/- knockout mice are further consistent with this view. To address the cellular interactions and functional consequences of Plxnd1 deficiency in thymic development, the present proposal will pursue three major aims. First, we will focus on the role of plexinD1 in regulation of CCR9/CCL25 and CXCR4/CXCL12 pathways and the directed migration of DP thymocytes using Ccr9-/- and Cxcr4 conditional knockout mice. Specifically, the links between these chemokine signaling pathways and Plxnd1 deficiency as well as the associated retarded thymocyte migration towards the medulla of pre-selected (CD69-) and post-selected (CD69+) DP thymocytes will be assessed. Second, we will analyze by multi-photon excitation microscopy the dynamics of GFP- expressing (green) Plxnd1-/- thymocytes in fetal liver-transplanted mice interacting with tdTomato (red) cortical thymic epithelial cells within renal subcapsular fetal thymic implants, using CFP-expressing (blue) wild type cells as an internal control. Third, we will analyze the impact of Plxnd1 deficiency on negative selection during T cell development using OT-I/OT-II TCR and RIP-OVA transgenic mice and fetal liver cell transplantation, in particular screening mice transplanted with Plxnd1-/- fetal liver cells for evidence of autoimmune phenomena. Collectively, our studies will offer insight into the molecular basis of plexinD1-mediated regulation of DP thymocyte movements within the thymus with consequential effects upon thymocyte differentiation and selection that may lead to autoimmune pathology in the mature immune system. PUBLIC HEALTH RELEVANCE: T cell function is critical for mammalian host protection against a wide variety of infectious disorders and cancers. T cells emanate from the thymus. Hence, understanding of the processes required for normal thymic architecture, differentiation and maturation will contribute to generation of more effective immunity.

描述（由申请人提供）：胸腺细胞的成熟和胸腺结构取决于精确的内膜细胞迁移。然而，在分子水平上，胸腺细胞运输的编排尚未得到很好的了解。最近，我们描述了CD4+ CD8+双阳性（DP）胸腺细胞上高度调节的Plexind1表达，该胸腺细胞通过T细胞受体/共受体接合进一步修饰。 Plexind1通过其配体Semaphorin 3E（SEMA3E）激活CXCR4/CXCL12信号在选择前的DP胸腺细胞中的信号传导和CD69+后选择后DP胸腺细胞中的CCR9/CCL25信号传导。使用PLXND1缺陷型胎儿肝细胞移植小鼠，Plexind1的损失会导致CD69+胸腺细胞保留在皮质中，并原位成熟以形成异位单（SP）阳性（SP）胸腺细胞簇。结果，皮质囊肿连接处的DP和SP胸腺细胞之间的边界被中断，在胸腔胶囊下形成髓质结构。这些结果证明了Plexind1通过调节趋化因子梯度的生物学反应来指导成熟胸腺细胞的迁移的重要性。在PLXND1 - / - 和SEMA3E - / - 基因敲除小鼠中观察到的畸形皮质形成结构与这种观点进一步一致。为了解决PLXND1缺乏在胸腺发育中的细胞相互作用和功能后果，本提案将追求三个主要目标。首先，我们将重点关注Plexind1在使用CCR9 - / - 和CXCR4条件敲除小鼠的CCR9/CCL25和CXCR4/CXCL12途径调节中的作用以及DP胸腺细胞的定向迁移。具体而言，将评估这些趋化因子信号通路与PLXND1缺乏以及相关的胸腺细胞向预选（CD69-）和后选择后（CD69+）DP胸腺细胞的髓质迁移之间的联系。其次，我们将通过多光子激发显微镜分析GFP表达（绿色）PLXND1 - / - 胸腺细胞在胎儿肝移植的小鼠中与TDTOMATO（红色）皮质胸腺皮质上皮细胞相互作用的肾脏下胎胸膜内部抗蛋白质抗蛋白质的bulleempress（bullue）的胸膜胸膜上皮细胞（红色）皮质胸膜上皮细胞（蓝色）的动力学。第三，我们将使用OT-I/OT-II TCR和RIP-OVA转基因小鼠以及胎儿肝细胞移植，特别是用PLXND1 - / - 胎儿肝细胞移植的筛查小鼠，使用OT-I/OT-II TCR和RIP-OVA转基因小鼠和胎儿肝细胞移植，分析PLXND1缺乏症对T细胞发育过程中负选择的影响。总的来说，我们的研究将深入了解胸腺内的PLEXIND1介导的DP胸腺细胞运动的调节，并对胸腺细胞分化和选择的结果影响，这可能导致成熟免疫系统中的自身免疫性病理。 公共卫生相关性：T细胞功能对于哺乳动物的宿主保护对各种传染病和癌症至关重要。 T细胞从胸腺中散发出来。因此，了解正常胸腺结构所需的过程，分化和成熟将有助于产生更有效的免疫力。