B61 FUNCTION DURING VASCULAR DEVELOPMENT

B61 在血管发育过程中的功能

• 批准号: 6139265
• 负责人: JOSEPH C. RUIZ
• 金额: $ 10.45万
• 依托单位: INDIANA UNIV-PURDUE UNIV AT INDIANAPOLIS
• 依托单位国家: 美国
• 财政年份: 1998
• 资助国家: 美国
• 起止时间: 1998-01-10 至 2001-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6139265
• 关键词: angiogenesis; biological signal transduction; carcinogenesis; cell differentiation; embryo /fetus; embryonic stem cell; gene expression; gene mutation; gene targeting; genetic mapping; genetically modified animals; immunocytochemistry; laboratory mouse; ligands; mammalian embryology; protein tyrosine kinase; tissue /cell culture; vascular endothelium

DESCRIPTION (Adapted from Investigator's Abstract): Progressive growth of tumors is dependent on continuous stimulation of new blood vessel formation. Considerable evidence indicates that receptor-protein tyrosine kinases (R-PTKs) and their ligands have crucial roles in the differentiation of endothelial cells and their subsequent organization into the vascular system. "Knockout mice" carrying mutations in endothelial cell specific R-PTKs and ligands, such as flk-1, flk-1, tie-2, and VEGF, result in embryonic lethality due to aberrant vascular development. Interestingly, mutation in each gene gives rise to distinct phenotypic abnormalities. These data indicate that multiple signaling pathways, each with nonoverlapping functions, are required for elaboration of the endocardium and vasculature. It will be essential to identify and characterize other loci that contribute to endothelial cell development in order to define the multiple pathways required for vasculogenesis and angiogenesis. B61, the major ligand for the ECK R-PTK (B61 also binds other members of the eph family), was shown by others to possess angiogenic and endothelial cell attractant activity. Consistent with this notion, B61 is expressed at sites of blood vessel formation during mouse embryogenesis. These data raise the intriguing possibility that B61 has a major role in recruiting endothelial cells into the developing vasculature. To test this hypothesis, first, candidate receptors for the B61 ligand will be identified by screening each member of the eph family for expression in the developing mouse vascular system by whole mount immunohistochemistry. Second, gene targeting in embryonic stem cells will be used to generate mice that carry null mutations at the B61 locus. Homozygous mutant embryos will be analyzed for defects in endothelial cell and blood vessel development. The extent of vascular development in mutant embryos will be assessed by histological analysis and by examination of the expression of three genes, flk-1, flt-1 and tek , that are markers for early to late stages of endothelial cell differentiation. Third, to assess the role of B61 and eck in tumor angiogenesis, embryonic stem cell lines that carry double knockouts at the B61 and/or eck loci (i.e., B61-1- and/or eck-1 cell lines) will be used to generate teratocarcinomas in syngeneic or immunocompromised mice. Tumors will be examined after four weeks for extent of tumor growth and vascular development. It is anticipated that these data will provide insight into the function of the B61/ECK signaling pathway in vascular development during embryogenesis and tumorigenesis.

描述（改编自研究者摘要）： 肿瘤依赖于新血管形成的持续刺激。 大量证据表明受体蛋白酪氨酸激酶 （R-PTKs）及其配体在肿瘤细胞分化中起着至关重要的作用。 内皮细胞及其随后组织成血管 系统 “敲除小鼠”携带内皮细胞特异性 R-PTK和配体，如flk-1、flk-1、tie-2和VEGF，导致 由于异常的血管发育导致的胚胎死亡。 有趣的是， 每个基因的突变引起不同的表型异常。 这些数据表明，多种信号通路，每一个与 不重叠的职能，需要详细说明内 和脉管系统。 必须确定和描述其他 基因座，有助于内皮细胞的发展，以确定 血管生成和血管生成所需的多种途径。 B61， ECK R-PTK的主要配体（B61也结合Eph的其它成员 家族），被其他人证明具有血管生成和内皮细胞 引诱活性 与此概念一致，B61表示为 小鼠胚胎发育过程中血管形成的部位。 这些数据 提出了一种有趣的可能性，即B61在招募方面发挥了重要作用， 内皮细胞进入发育中的脉管系统。 为了验证这个假设， 首先，将通过以下方法鉴定B61配体的候选受体： 筛选Eph家族的每个成员在发育中的细胞中的表达， 小鼠血管系统整体包埋免疫组化。 第二，基因 胚胎干细胞中的靶向将用于产生携带 B61位点的无效突变。 将分析纯合突变胚胎 用于内皮细胞和血管发育缺陷。 的程度 将通过组织学方法评估突变胚胎中的血管发育。 分析并通过检测flk-1、flt-1 和TEK，它们是内皮细胞早期到晚期的标志物， 分化 第三，探讨B61和eck在肿瘤中的作用 血管生成，胚胎干细胞系，携带双敲除在 B61和/或eck基因座（即，B61-1-和/或eck-1细胞系）将用于 在同基因或免疫缺陷小鼠中产生畸胎瘤。 肿瘤 四周后将检查肿瘤生长和血管的程度。 发展 预计这些数据将提供深入了解 B61/ECK信号通路在血管发育中的作用 胚胎发生和肿瘤发生。