Epithelial-mesenchymal interactions in gut morphogenesis

描述（申请人提供）： 上皮-间质相互作用对于正常形态发生至关重要 和维持隐窝-绒毛轴。调节这些的分子 直到最近才开始描述相互作用。我们有 确定了一种间充质蛋白，epimorphin，作为一种假定的调节剂， 上皮形态发生我们发现这种分子对 肠上皮的形态发生和分化。但 表吗啡肽发挥其作用的机制尚不清楚， 在整个动物中抑制表吗啡肽表达的效果还没有被证实。 介绍了我们对这一应用的假设是，epimorphin的作用是 至少部分通过调节可溶性物质的分泌来介导 在形态发生中很重要。根据我们的初步数据， 候选人可能是音速刺猬（嘘）的关键调节器， 早期肠道个体发育中的肠道-内胚层-间充质信号传导。我们证明了 通过抗体输注阻断hedgehog信号通路， 出生后肠道形态发生变化，绒毛紊乱， 死亡这些作用在体外的上皮-肌成纤维细胞中重现。 共培养模型。当前的主要假设 建议如下：1.肠肌成纤维细胞产生表吗啡肽， 隐窝-绒毛轴的形成和维持。2. Hedgehog信号 这些通路是维持出生后隐窝-绒毛轴所必需的。 具体目标是：1。确定epimorphin诱导 隐窝绒毛形态发生和细胞分化。2.确定体内 通过创建表吗啡肽-/-小鼠来研究表吗啡肽的功能。3.确定是否 hedgehog对生后上皮细胞形态发生的影响 分化是通过上皮-间充质相互作用介导的， 上皮-肌成纤维细胞共培养系统。其意义 应用程序是基于我们最近确定的一个 间充质/肌成纤维细胞基因，在调节 腺-绒毛轴形态发生。Hedgehog信号在出生后发育中的作用 肠道个体发育也已建立，并将进一步研究。具体 对于本RFA的研究范围，这些研究将描述 上皮间充质串扰的基础正常发展。我们还将 建立一种新的模型，epimorphin null小鼠，用于表征 间充质细胞群的分子特性， 在发育和成年胃肠道中的上皮细胞更新。

DESCRIPTION (Provided by Applicant): Epithelial-mesenchymal interactions are critical for the normal morphogenesis and maintenance of the crypt-villus axis. The molecules that regulate these reciprocal interactions have only recently begun to be described. We have identified a mesenchymal protein, epimorphin, as a putative regulator of epithelial morphogenesis. We show that this molecule has profound effects on morphogenesis and differentiation of the intestinal epithelium. However, the mechanism by which epimorphin exerts its effects is unknown, and the in vivo effects of inhibiting epimorphin expression in whole animals have not yet been described. Our hypothesis for this application is that epimorphin's effects are mediated, at least in part, by regulating the secretion o soluble substances that are important in morphogenesis. Based on our preliminary data, one such candidate may be sonic hedgehog (Shh)a critical regulator of gut-endodermal-mesenchymal signaling in early gut ontogeny. We show that blocking hedgehog signaling pathways by antibody infusion produces profound changes in postnatal gut morphology, with disorganized villi, runting and early death. These effects are recapitulated in vitro in an epithelial-myofibroblast co-culture model developed in our lab. The major hypotheses of the current proposal are: 1. Intestinal myofibroblasts produce epimorphin which regulates the formation and maintenance of the crypt-villus axis. 2. Hedgehog signaling pathways are required for the maintenance of the postnatal crypt-villus axis. The Specific Aims are: 1. Determine the mechanisms by which epimorphin induces crypt-villus morphogenesis and cytodifferentiation. 2. Determine the in vivo function of epimorphin by creating epimorphin -/- mice. 3. Determine whether the effects of hedgehog on postnatal epithelial morphogenesis and differentiation are mediated via epithelial-mesenchymal interactions, using an epithelial-myofibroblast co-culture system. The significance of this application is based on our recent identification of a mesenchymal/myofibroblast gene that plays an important role in the regulation of crypt-villus axis morphogenesis. A role for hedgehog signaling in postnatal gut ontogeny has also been established and will be further examined. Specific to the research scope for this RFA, these studies will characterize epithelial-mesenchymal cross talk underlying normal development. We will also establish a novel model, the epimorphin null mouse, for characterizing the molecular properties of the mesenchymal cell populations that regulate epithelial cell renewal in the developing and adult GI tract.