CONGENITAL CARDIOVASCULAR PATHOLOGY & CX43 GAP JUNCTION GENE

心血管缺陷是人类最常见的缺陷 婴儿，影响200名活产儿中的一名。尽管许多人 这些心脏畸形有明确的表型，目前 很少有候选基因被确定在 这些心脏畸形。最近的研究表明，连接蛋白 43(Cx43)缝隙连接基因可能是其中一个候选基因。Cx43 基因敲除(KO)小鼠出生时死于圆锥干缺陷 与肺动脉狭窄和室间隔缺陷症相关。 鉴于之前的消融研究已经表明 枕神经脊细胞在圆锥干发育中的作用 神经脊细胞的扰动可能是 由Cx43基因扰动引起的心血管畸形。 与这种可能性相一致的是，神经脊细胞 表达Cx43缝隙连接基因，并通过 缝隙连接。此外，Cx43在CMV43转基因中的表达 小鼠是由巨细胞病毒启动子驱动的，这种启动子 将转基因表达限制在背侧神经管，并且 神经脊细胞亚群，包括神经脊细胞 迁移到心脏流出道处。根据这些观察结果， 我们建议进行实验，以进一步检验微扰是否 神经脊细胞可能是心血管畸形的基础 在Cx43功能缺失的小鼠中。我们将描述 Cx43KO和CMV43转基因小鼠的心血管形态发生 使用组织学、超声心动图和核磁共振分析。我们将表演 对活体胚胎(宫内)进行超声心动图检查，送怀孕的雌性 为了杜克大学，给胚胎灌流BSA-DTPA-Gd，进行快速检查 扫描每个胚胎，然后对每个胚胎执行3D自旋回波扫描 在调查扫描中看起来很有希望的纯合子KO胚胎。我们 预计将准备4胎胚胎，并进行3D扫描 在9T磁铁上有6-8个胚胎。

Cardiovascular defects are the most common defects in human infants, affecting one of two hundred live births. Although many of these cardiac malformations have well defined phenotypes, currently very few candidate genes have been identified as playing a role in these heart malformations. Recent studies suggest that the connexin 43 (Cx43) gap junction gene may be one such candidate gene. Cx43 knockout (KO) mice die at birth as a result of conotruncal defects associated with pulmonary stenosis and ventricular septal defects. Given that previous ablation studies have shown the importance of occipital neural crest cells in conotruncal development, we suggest that perturbation of neural crest cells may underlie the cardiovascular malformations resulting from Cx43 perturbation. Consistent with this possibility is the fact that neural crest cells express the Cx43 gap junction gene, and are functionally coupled via gap junctions. Furthermore, Cx43 expression in the CMV43 transgenic mice is driven by the cytomegaloviral promoter, a promoter which restricts transgene expression to the dorsal neural tube, and a subpopulation of neural crest cells, including neural crest cells that migrate to the heart outflow tract. In light of these observations, we propose experiments to further examine whether perturbation of neural crest cells may underlie the cardiovascular malformations seen in mice harboring the loss of Cx43 function. We will characterize cardiovascular morphogenesis in the Cx43 KO and CMV43 transgenic mice using histology, echocardiography, and MRI analyses. We will perform echocardiography on live embryos (in-utero), send the pregnant female to Duke, perfuse the embryos with BSA-DTPA-Gd, perform a quick survey scan of each embryo, and then perform a 3D spin echo scan on homozygote KO embryos that looked promising in the survey scans. We anticipate preparing 4 litters of embryos, and performing 3D scans on 6-8 of the embryos on the 9T magnet.