Role of Plexin D1 in thymic development

Plexin D1 在胸腺发育中的作用

• 批准号: 7587367
• 负责人: LINDA KATHLEEN CLAYTON
• 金额: $ 16.03万
• 依托单位: DANA-FARBER CANCER INST
• 依托单位国家: 美国
• 财政年份: 2008
• 资助国家: 美国
• 起止时间: 2008-04-01 至 2010-03-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/7587367
• 关键词: Adhesions; Animals; Bacteria; Binding; Cell Fate Control; Cells; Communicable Diseases; Cues; Development; Family; Fetal Liver; Gene Expression; Gene Targeting; Genes; Immune system; Individual; Knock-out; Ligands; Location; Lymphoid; Lymphopoiesis; Malignant - descriptor; Movement; Neonatal; Nervous system structure; Organ; Pattern; Persons; Play; Process; Public Health; Role; Semaphorins; Signal Transduction; T-Lymphocyte; Thymocyte Development; Thymus Gland; Traction; Transcriptional Regulation; Transgenic Mice; Upper arm; Vaccine Design; Virus; axonal guidance; base; blastocyst; embryonic stem cell; in vivo; liver transplantation; member; migration; mouse model; mutant; novel strategies; overexpression; plexin; prevent; progenitor; promoter; public health relevance; thymocyte

DESCRIPTION (provided by applicant): Thymic development is a highly choreographed differentiation process involving distinct lymphoid-stromal interactions in defined cortical and medullary locations. Lymphopoiesis of the T lineage in the thymus proceeds in a directional manner such that early double negative (DN) progenitors enter the perimedullary cortex and then move outward to the subcapsule while, conversely, double positive (DP) thymocytes flow inward toward the medulla. Such movement requires adhesion mechanisms for traction as well as attractive or repulsive cueing signals. We have performed in vivo global gene expression analysis of thymocyte developmental subpopulations and determined that the plxnd1 gene is rapidly repressed by ~ 100 fold as development proceeds from DP to single positive (SP) thymocytes. This gene encodes PlexinD1, an ill-defined member of the plexin family of axonal guidance molecules that bind secreted and cell-bound semaphorins to control cell fate in the nervous system. The expression pattern of other plexins in the thymus is distinct from that of Plexin D1. Furthermore, candidate semaphorin ligands (3F, 3G, 4B, 4D, 4G, 6D, and 7A) are under strict spatial transcriptional control in the thymus. Based on precedent with axonal guidance in the nervous system, we hypothesize that plexin-semaphorin interaction will allow for positional localization of various thymocyte subpopulations at specific developmental states. The purpose of this proposal is to generate animals in addition to the plxnd1-/- mutant, which results in neonatal lethality thus preventing analysis of T lymphoid development. The traditional plxnd1-/- will be used to analyze the consequences of plxnd1 disruption using plxnd1-/- ES cells and RAG-2-/- blastocyst complementation, as well as plxnd1-/- fetal liver transplantation. Utilizing transgenic mice in which plxnd1 expression is driven by the CD2 promoter, the effect of plxnd1 over-expression on thymocyte development and migration will be determined. Development of plxnd1-/- thymocytes within plxnd1 wild type thymic stroma will be analyzed using conditional, thymus-specific plxnd1 knockout strategies. The mouse models resulting from the implementation of the overexpression and conditional knockout strategies will greatly aid our analysis of the role PlexinD1 plays in thymic development. Project Narrative PUBLIC HEALTH RELEVANCE: The thymus is an organ of the immune system in which all T lymphocytes that protect a person against infectious diseases are generated. T lymphocytes are an important arm of the immune system acting to recognize and attack cells in an individual's body that may be infected by viruses, bacteria or may be malignant. A detailed understanding of this thymic development is important for public health and may offer new approaches for vaccine design.

描述（由申请人提供）：胸腺发育是一个高度设计的分化过程，涉及在确定的皮质和髓质位置的不同淋巴-基质相互作用。胸腺中T细胞系的造血以定向方式进行，使得早期双阴性（DN）祖细胞进入髓周皮质，然后向外移动到被膜下，而相反，双阳性（DP）胸腺细胞向内流向髓质。这种运动需要附着机制来牵引以及吸引或排斥提示信号。我们对胸腺细胞发育亚群进行了体内整体基因表达分析，并确定plxnd 1基因在从DP到单阳性（SP）胸腺细胞的发育过程中被快速抑制约100倍。该基因编码丛蛋白D1，一种轴突导向分子丛蛋白家族的不明确成员，其结合分泌的和细胞结合的信号蛋白以控制神经系统中的细胞命运。胸腺中其他丛蛋白的表达模式与丛蛋白D1的表达模式不同。此外，候选脑信号蛋白配体（3F，3G，4 B，4D，4G，6D和7A）在胸腺中受到严格的空间转录控制。基于神经系统中轴突引导的先例，我们假设丛蛋白-脑信号蛋白相互作用将允许各种胸腺细胞亚群在特定发育状态下的位置定位。该提案的目的是产生除plxnd 1-/-突变体之外的动物，plxnd 1-/-突变体导致新生儿致死，从而阻止T淋巴发育的分析。传统的plxnd 1-/-将用于分析使用plxnd 1-/- ES细胞和RAG-2-/-囊胚互补以及plxnd 1-/-胎肝移植的plxnd 1破坏的后果。利用plxnd 1表达由CD 2启动子驱动的转基因小鼠，将确定plxnd 1过表达对胸腺细胞发育和迁移的影响。将使用条件性胸腺特异性plxnd 1敲除策略分析plxnd 1野生型胸腺基质内plxnd 1-/-胸腺细胞的发育。实施过表达和条件性敲除策略所产生的小鼠模型将极大地帮助我们分析丛蛋白D1在胸腺发育中所起的作用。项目叙述 公共卫生关系：胸腺是免疫系统的一个器官，其中产生所有保护人免受传染病的T淋巴细胞。T淋巴细胞是免疫系统的重要分支，其作用是识别和攻击个体体内可能被病毒、细菌感染或可能是恶性的细胞。详细了解这种胸腺发育对公共卫生非常重要，并可能为疫苗设计提供新的方法。