Physical Signaling Mechanisms That Regulate Intestinal Architecture

项目摘要 物理信号越来越多地被认为在调节细胞行为中起着重要作用。的 该提案的目标是表征肠道中对力介导的信号传导的细胞反应， 食管的研究。我们已经证明，在光滑的， 肌肉肌球蛋白重链基因myh 11破坏斑马鱼融化突变体的肠道结构 突变肌球蛋白产生的物理信号激活了细胞内保守的氧化还原信号通路。 肠上皮细胞驱动质膜突起的形成，称为侵入伪足， 降解基质蛋白。侵入伪足驱动了肿瘤的侵入性转化和囊性扩张。 上皮融合突变杂合子的动物发育正常，但对 当致癌信号通路激活时，形成纯合细胞侵袭表型。该提案 由三个目标组成，旨在了解来自不受调节的肌球蛋白的物理信号是如何处理的。 以及它们如何成为消化系统疾病的危险因素。 第一个目标是了解突变的平滑肌肌球蛋白是如何启动侵袭性伪足的， 上皮细胞的熔化突变体，并比较这一机制，调节侵袭伪足的形成 在哺乳动物细胞中。在体内很少观察到侵入伪足，因此这一目的提供了 有机会了解它们在活体动物模型中的调节。第二个目标的目标是 了解KRas和Wnt信号的共激活如何使杂合突变体对侵袭性 触发器为此目的提出的实验具有基础和临床相关性，因为这两种途径 在人类消化道癌症中被激活。第三个目标的目标是描述一个最近设计的 一个崩溃突变的小鼠模型。这包括食管和肠的表征 纯合突变体中的表型，并与新工程改造携带基因敲入的小鼠比较 与遗传性运动综合征相关的人类MYH11突变相同的突变。 总的来说，拟议的实验将定义新的因素和信号机制，建立和 维持消化器官的结构和功能。

PROJECT SUMMARY Physical signals are increasingly recognized as playing an important role in modulating cell behavior. The goal of this proposal is to characterize the cellular response to force-mediated signaling in the intestine and esophagus using zebrafish and mouse models. We have shown that an activating mutation in smooth muscle myosin heavy chain gene myh11 disrupts intestinal architecture in zebrafish meltdown mutants. Physical signals arising from the mutant myosin activate a conserved redox signaling pathway in the intestinal epithelium that drives the formation of plasma membrane protrusions known as invadopodia that degrade matrix proteins. The invadopodia drive the invasive transformation and cystic expansion of the epithelium. Animals that are heterozygous for the meltdown mutation develop normally but are sensitized to form the homozygous cell invasion phenotype when oncogenic signaling pathways activated. The proposal consists of three aims designed to understand how physical signals from unregulated myosin are processed by digestive epithelia and how they may be risk factors for digestive disease. The goal of the first aim are to understand how the mutant smooth muscle myosin initiates invadopodia in the epithelium of meltdown mutants and to compare this to mechanisms that regulate invadopodia formation in mammalian cells. Invadopodia have rarely if ever been observed in vivo, thus this aim offers the opportunity to understand their regulation in a live animal model. The goal of the second aim is to understand how co- activation of KRas and Wnt signaling sensitize heterozygous mutants to invasive triggers. The experiments proposed for this aim have both basic and clinical relevance, as both pathways are activated in human digestive cancers. The goal of the third aim is to characterize a recently engineered mouse model of the meltdown mutation. This includes characterization of esophageal and intestinal phenotypes in homozygous mutants, and comparison with mice newly engineered to carry knock-in mutations that are identical to human MYH11 mutations associated with heritable motility syndromes. Collectively, the proposed experiments will define novel factors and signaling mechanisms that establish and maintain digestive organ architecture and function.