Transcriptional clues to esophageal atresia pathogenesis

项目摘要 食管闭锁是世界范围内最常见的先天性食管疾病 每3,500个活产婴儿中就有一个。EA可以作为一个孤立的发现，或与综合征或 非综合征性发育异常如果不治疗，EA是一种致命的疾病，因为闭锁段 阻塞了食道幸运的是，几乎所有的婴儿都可以通过手术治愈， 由于食管动力受损导致的严重胃食管返流和吞咽困难。虽然 EA的原因尚不清楚，遗传成分是根据其在复杂发育过程中的发生来预测的。 tal综合征及其在单卵双胞胎与双卵双胞胎中较高发病率。没有单一的基因突变 最终证明是导致EA的原因。我们已经开发了第一个孤立的EA动物模型， 平滑肌肌球蛋白重链基因（Myh 11）突变，我们以前已经证明，改变肌球蛋白 调控在斑马鱼中，相同的突变导致肠道的侵入性扩张。在小鼠中，predomi- Nant表型为EA，尽管检测到侵袭性样肠道病变。突变破坏了 肌球蛋白调节改变导致的肌肉收缩性。这表明MYH 11和MYH 12中的遗传变异 其他平滑肌调节基因可能导致EA及其相关的食管动力障碍。 在EA表型消失之前，Myh 11突变体食管的初步转录谱研究 tected显示了神经系统和横纹肌发育相关基因的调节改变。这 提示食管神经肌肉功能缺陷可能是与EA相关的内在缺陷， 与闭锁无关。支持这一点的是，免疫染色显示食管神经纤维密度改变， 变异食管中食管神经节数量和大小减少以及横纹肌发育改变 这项提案的目标是通过检查这些和其他基因表达变化来扩展这些发现 在较老的Myh 11突变体中，通过定量神经元密度和神经元亚型的变化， 食管神经元原代培养物的体外功能分析。

Project Summary Esophageal atresia (EA) is the most common congenital disorder of the esophagus with a worldwide incidence of about 1 in 3,500 live births. EA can occur as an isolated finding, or in combination with either syndromic or non-syndromic developmental anomalies. Left untreated, EA is a fatal disorder because the atretic segment obstructs the esophagus. Fortunately, it can be cured surgically in nearly all infants, however the majority suffer from severe gastroesophageal reflux and dysphagia as a result of impaired esophageal motility. Although the cause of EA is not known, a genetic component is predicted based on its occurrence in complex developmen- tal syndromes and its higher incidence in monozygotic vs. dizygotic twins. No single gene mutations have been conclusively shown to cause EA. We have developed the first animal model of isolated EA by engineering a mutation in the smooth muscle myosin heavy chain gene (Myh11) that we have previously shown alters myosin regulation. In zebrafish, the identical mutation causes invasive expansion of the intestine. In mice the predomi- nant phenotype is EA, although invasive-like intestinal lesions are detected. The mutation disrupts smooth muscle contractility as a result of altered myosin regulation. This suggests that genetic variants in MYH11 and other smooth muscle regulatory genes could cause both EA and its associated esophageal motility disorders. Preliminary transcriptional profiling studies of esophagi from Myh11 mutants before the EA phenotype is de- tected showed altered regulation of genes involved in nervous system and striated muscle development. This suggest that defects in esophageal neuromuscular function may be an intrinsic defect associated with EA that arises independently of atresia. Supporting this, immunostainings show altered esophageal nerve fiber density, reduced number and size of esophageal ganglia and altered striated muscle development in mutant esophagi The goal of this proposal is to expand these findings by examining these and other gene expression changes in older Myh11 mutants, by quantifying changes in neuronal density and neuronal subtypes, and by conducting in vitro functional analyses in primary cultures of esophageal neurons.