Gap Junctions in Cell-Cell Communication (Supplement)

描述（由申请人提供）：这是NHLBI资助#HL53318“微血管中的细胞间通讯”的竞争补充提案。总体假设或主题是平滑肌和内皮作为一个整体单位在心血管功能的调节中发挥作用，以及2）。连接两种细胞的分子是连接蛋白。父R-01建议研究三个连接蛋白; 43，40和37。连接蛋白40和37的敲除动物已从合作者获得。由于连接蛋白43的缺失在胚胎学上是致命的，我们已经创建了细胞特异性敲除，其中连接蛋白43的表达在平滑肌或内皮中被选择性地消除。 在提交亲本R-01赠款时，我们指出，要更充分地了解血管壁中连接蛋白的生物学特性，就必须通过适当的杂交育种产生双敲除。我们选择连接蛋白43和40作为第一个双敲除，这是基于我们可以将43的缺失限制在内皮，并且我们的免疫细胞化学显示，与其他连接蛋白相比，连接蛋白40在小鼠中在内皮中大量表达。我们现在已经发现，内皮细胞特异性Cx43 KO与Cx40 KO交叉在大约3个月大时产生快速进展的高血压、严重的心脏肥大和衰竭。该表型似乎是超负荷心脏肥大和衰竭的模型。重要的是，内皮细胞缺失的杂合子动物显示出类似的表型，证明了表型的突变。我们已经与心脏MRI小组建立了合作关系，现在能够在这个模型中测量心脏适应和衰竭的进展。这些数据支持需要一个加速育种计划，以产生足够的双敲除，并应用高通量筛选功能的评估。竞争性补编的具体目标是：1.扩大我们的育种和动物维护，使我们能够探索双连接蛋白敲除动物的血管功能。2.对由一个或多个连接蛋白基因的消除引起的心血管生理学变化进行纵向测量。具体来说，我们将跟踪血压，心输出量，心率，心电图和外周阻力，在几个月的高血压，心脏肥大和最终失败的发展。这些数据将与我们正在进行的微血管功能测量相关联。

DESCRIPTION (provided by applicant): This is a proposal for a Competing Supplement to NHLBI grant #HL53318, Intercellular Communication in Microvessels. The overarching hypotheses or themes are that smooth muscle and endothelium function as an integrated unit in the regulation of cardiovascular function, and 2.) that the coordinating molecule uniting the two cell types is the connexin. The parent R-01 proposes to study three of the connexins; 43, 40, and 37. Knockout animals for connexin 40 and 37 have been obtained from a collaborator. Because deletion of the connexin 43 is embryologically lethal, we have created cell-specific knockouts in which connexin 43 expression is selectively eliminated in either smooth muscle or endothelium. At the time of submission of the parent R-01 grant we indicated that fuller understanding of the biology of the connexins in the vessel wall would necessitate the production of double knockouts through appropriate cross breeding. We selected connexin 43 and 40 as the first double knockout to be produced based on the facts that we could restrict deletion of 43 to the endothelium, and that our immuno-cytochemistry shows connexin 40 in the mouse to be abundantly expresses in the endothelium compared to the other connexins. We have now found that the endothelial cell-specific Cx43 KO crossed with the Cx40 KO produces rapidly advancing hypertension, profound cardiac hypertrophy and failure at about 3 months of age. The phenotype appears to be a model for overload cardiac hypertrophy and failure. Importantly, animal heterozygous for the endothelial cell deletion show a similar phenotype attesting to the penetrance of the phenotype. We have established a collaboration with the cardiac MRI group here and are now able to measure the progression of cardiac adaptation and failure in this model. These data support the need for an accelerated breeding program to designed to generate sufficient double knockouts, and to apply high throughput screening to the assessment of function. The specific aims of the Competing Supplement are: 1. to expand our breeding and animal maintenance to allow us to explore the vascular function in animals with double connexin knockouts. 2. to conduct longitudinal measurements on changes in cardiovascular physiology caused by the elimination of one or more of the connexin genes. Specifically, we will follow blood pressure, cardiac output, heart rate, EKG, and peripheral resistance, over several months of the development of hypertension, cardiac hypertrophy and ultimately failure. These data will be correlated with our ongoing measurements of microvascular function.