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Embryonic pulmonary vascular development during murine lung morphogenesis

小鼠肺形态发生过程中的胚胎肺血管发育

基本信息

批准号：
14570759
负责人：
HAMAOKA Kenji
金额：
$ 2.56万
依托单位：
Kyoto Prefectural University of medicine
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2002
资助国家：
日本
起止时间：
2002 至 2003
项目状态：
已结题

项目摘要

Backgrounds:Impaired pulmonary vasculature is a serious complication of cyanotic congenital heart diseases. Understanding the molecular mechanisms of the pulmonary vascular development is essential for molecular-based gene and regeneration therapies. Vascular endothelial growth factor (VEGF) and its receptors, Flk-1 and Flt-1,are known to be important factors that regulate vascular development. This study focuses on spatiotemporal expression and experimental inhibition of Flk-1 and Flt-1 during the development of pulmonary vasculature.Methods:The expressions of Flk-1 and F1t-1 in murine embryonic lungs were examined by immunohistochemistry and the functions were studied by using antisense oligonucleotides in vitro. DNA synthesis of vascular endothelial cells was studied by BrdU incorporation.Results:Based on the relationship between Vascular endothelial cells and bronchial epithelial cells, development of pulmonary vasculature is divided into 4 stages. Flk-1 is diffusely expressed in mesenchymal cells at stage I-III, and is less expressed at stage IV. Flt-1 is initially detected in mesenchymal cells surrounding bronchial epithelium at stage II, its expression peaks at stage III, and decreases at stage IV. VEGF protein is expressed both in pulmonary epithelial cells and adjacent mesenchymal cells throughout the stages. DNA synthesis of vascular endothelial cell is up-regulated at stages I and II, and down-regulated after stage III. Treatment of cultured lung buds with antisense oligonucleotides complementary to Flk-1 resulted in insufficient branching of capillaries and impaired proliferation of vascular endothelial cells. Contrary, treatment with antisense oligonucleotides complementary to Flt-1 promotes vascular branching of capillaries and increased proliferation of vascular endothelial cells.Conclusion:Expressions of Flk-1 and Flt-1 were crucial elements of the normal development of the pulmonary vasculature.

背景：肺血管受损是紫绀型先天性心脏病的严重并发症。了解肺血管发育的分子机制对于基于分子的基因和再生治疗是必不可少的。血管内皮生长因子（VEGF）及其受体Flk-1和Flt-1是调节血管发育的重要因子。方法：采用免疫组织化学方法检测Flk-1和Flt-1在小鼠胚胎肺组织中的表达，并利用反义寡核苷酸进行体外功能研究。结果：根据血管内皮细胞与支气管上皮细胞的关系，肺血管的发育可分为4个阶段。Flk-1在I-III期的间充质细胞中弥散表达，而在IV期表达较少。Flt-1最初在II期支气管上皮周围的间充质细胞中检测到，其表达在III期达到峰值，并在IV期降低。VEGF蛋白在肺上皮细胞和邻近的间充质细胞中表达。血管内皮细胞DNA合成在I、II期上调，III期后下调。用Flk-1互补的反义寡核苷酸处理培养的肺芽导致毛细血管分支不足和血管内皮细胞增殖受损。结论：Flk-1和Flt-1的表达是肺血管正常发育的重要因素。