Imaging fluid forces in mouse cardiovascular development

小鼠心血管发育中的流体力成像

• 批准号: 6969001
• 负责人: Mary E Dickinson
• 金额: $ 36.25万
• 依托单位: BAYLOR COLLEGE OF MEDICINE
• 依托单位国家: 美国
• 财政年份: 2005
• 资助国家: 美国
• 起止时间: 2005-09-01 至 2008-08-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6969001
• 关键词: angiogenesis; bioimaging /biomedical imaging; blood circulation; blood vessels; cardiogenesis; cardiovascular function; cell morphology; confocal scanning microscopy; embryology; hemodynamics; imaging /visualization /scanning; laboratory mouse; mutant; polymerase chain reaction; shear stress; yolk sac

DESCRIPTION: The mouse provides an excellent system for studying congenital cardiovascular abnormalities defects since mouse and human development are very similar and many mutants with heart and vascular anomolies have been identified (Harvey, 2002). Blood flow and the formation of the heart and vasculature coincide, and several studies suggest that mechanical stimulus, imparted by the shear stress between blood flow and the endothelial cell wall, acts as a signal for vascular remodeling (see Topper and Gimbrone, 1999 for review). Using confocal laser scanning microscopy, we have developed methods to measure blood flow velocities and calculate shear stress levels in mouse embryos (Jones et at 2004b). Here we will test the hypothesis that mechano-sensory signals are necessary for proper development of the yolk sac vasculature using three sets of in vivo, multispectral imaging experiments: First, we will study how the vascular plexus forms using celltype specific fluorescent protein expression. We will describe how endothelial cell morphologies change as vessels are assembled and flow begins. Second, we will quantify changes in shear stress during early yolk sac vessel formation and remodeling to identify forces that induces morphogenesis. Third, we will quantify hemodynamics in Myosin Light Chain 2a (MLC2a) mutant embryos (Huang et al 2003) to test whether disrupted flow and reduced shear stress can cause abnormal development of vascular cells in the yolk sac. MLC2a -/- embryos are ideal for studying the effects of shear stress because mutants have defects in vessel formation even though MLC2a is never expressed outside the heart. Through these Specific Aims, we will gather vital information about the dyanamic development of the yolk sac vasculature and will test how mechanical signals relate to changing vessel morphology. We have focused on a single mutant strain here, but the quantitative methods employed can be used to study any mutant with impaired vascular development or impaired cardiovascular function.

描述：小鼠为研究先天性心血管异常缺陷提供了一个极好的系统，因为小鼠和人类的发育非常相似，并且已经鉴定出许多具有心脏和血管异常的突变体（Harvey，2002）。血流与心脏和脉管系统的形成是一致的，一些研究表明，血流和内皮细胞壁之间的剪切应力所产生的机械刺激充当血管重塑的信号（参见 Topper 和 Gimbrone，1999 年的综述） ）。使用共焦激光扫描显微镜，我们开发了测量小鼠胚胎血流速度并计算剪切应力水平的方法（Jones 等，2004b）。在这里，我们将使用三组体内多光谱成像实验来检验机械感觉信号对于卵黄囊脉管系统的正常发育所必需的假设：首先，我们将使用细胞类型特异性荧光蛋白表达来研究血管丛如何形成。我们将描述当血管组装和流动开始时内皮细胞形态如何变化。其次，我们将量化早期卵黄囊血管形成和重塑过程中剪切应力的变化，以确定诱导形态发生的力。第三，我们将量化肌球蛋白轻链 2a (MLC2a) 突变体胚胎的血流动力学 (Huang et al 2003)，以测试血流中断和剪切应力降低是否会导致卵黄囊中血管细胞的异常发育。 MLC2a -/- 胚胎是研究剪切应力影响的理想选择，因为突变体在血管形成方面存在缺陷，尽管 MLC2a 从未在心脏外表达。通过这些具体目标，我们将收集有关卵黄囊脉管系统动态发育的重要信息，并测试机械信号与血管形态变化的关系。我们在这里关注的是单一突变株，但所采用的定量方法可用于研究任何血管发育受损或心血管功能受损的突变株。