Role of Gata3 in pylorus development

描述(申请人提供)：项目摘要幽门是胃和肠之间的肌肉连接，调节食物进入十二指肠。一种相对常见的婴儿出生后病理是肥厚性幽门狭窄(HPS)，表现为抛射性呕吐和无法进食。在成人中，幽门功能障碍可导致胃十二指肠反流。这些幽门病变背后的分子和细胞病因尚不清楚，但更好地了解幽门及其相关肌肉连接的发育可能有助于揭示这些机制。本申请中提出的工作是基于最近的微阵列分析，该分析确定了一些在幽门独特表达的基因，包括转录因子Nkx2-5和GATA3。初步数据表明，GATA3和Nkx2-5在幽门的一个独特结构域内的平滑肌细胞中共表达。这两种蛋白也在以前未被描述的浅表索状结构中表达，这些结构由连接食道和幽门区域的平滑肌细胞组成。在GATA3基因缺失的小鼠中，特定的平滑肌细胞群丢失(包括肌索)，导致幽门收缩减少和胃窦形状改变。以前在雏鸡模型中的研究表明，Nkx2-5的缺失也影响幽门收缩，尽管它在细胞水平上的影响还没有研究。推动这项工作的假设是，GATA3是幽门功能相关的平滑肌种群发育所必需的，并且本身受Nkx2-5调节。在这些研究的目标1中，将对幽门发育进行仔细的分析，整合野生型小鼠幽门发育的细胞、分子和功能方面，并为进一步研究脊椎动物模型奠定重要的基线。我们还将研究平滑肌索的功能作用。在目标2中，将研究GATA3和Nkx2-5之间的功能相互作用，并阐明这两个蛋白之间的上位关系。在这些研究过程中，将使用一种新的组织培养系统来分析幽门收缩功能的发展以及Nkx2-5或GATA3缺失对这一功能的影响。总之，这项建议中描述的工作将提高我们对幽门特定平滑肌群的发育和功能的理解，并阐明GATA3和Nkx2-5在幽门发育中的作用，这些信息可能最终影响人类幽门病理的临床处理。

DESCRIPTION (provided by applicant): Project Summary The pylorus is the muscular junction between the stomach and intestine that regulates the passage of food into the duodenum. A relatively common postnatal pathology in infants is hypertrophic pyloric stenosis (HPS), which presents with projectile vomiting and inability to feed. In adults, pyloric malfunction can lead to gastro- duodenal reflux. The molecular and cellular etiologies underlying these pyloric pathologies are unknown, but a better understanding of the development of the pylorus and its associated muscular connections may shed light on these mechanisms. The work proposed in this application is based on a recent microarray analysis that identified a number of genes expressed uniquely at the pylorus, including the transcription factors, Nkx2-5 and Gata3. Preliminary data indicate that Gata3 and Nkx2-5 are co-expressed in smooth muscle cells within a unique domain at the pylorus. Both proteins are also expressed in previously undescribed superficial cord-like structures composed of smooth muscle cells that connect the esophagus to the pyloric region. In Gata3 null mice, specific groups of smooth muscle cells are lost (including the muscular cords), resulting in reduced pyloric constriction and alterations in the shape of the antrum. Previous studies in the chick model indicate that Nkx2-5 loss also affects pyloric constriction, though its effects at the cellular level were not studied. The hypothesis driving this work is that Gata3 is required for development of functionally relevant smooth muscle populations of the pylorus and is itself regulated by Nkx2-5. In Aim 1 of these studies, a careful analysis of pyloric development will be carried out, integrating cellular, molecular and functional aspects of pyloric development in the wild type mouse and setting an important baseline for further studies in vertebrate models. The functional role of the smooth muscle cords will also be studied. In Aim 2, the functional interaction between Gata3 and Nkx2-5 will be investigated and the epistatic relationship between these two proteins will be clarified. In the course of these studies, a novel tissue culture system will be employed to analyze the development of pyloric contractile function and the effects of loss of Nkx2-5 or Gata3 on this function. Together, the work described in this proposal will improve our understanding of the development as well as the function of specific smooth muscle groups at the pylorus and clarify the role of Gata3 and Nkx2-5 in pyloric development, information that could ultimately impact the clinical management of pyloric pathologies in humans.