Endocytic Regulation of Intestinal Development

肠道发育的细胞内调节 肠粘膜是一种高度分化的上皮屏障，是肠道正常功能的基础。 肠子。囊泡运输现在被认为是上皮极性、完整性和细胞的重要调节因子 分化，在模型系统中的研究表明，内吞作用和膜转运 对肠道的正常个体发育是必不可少的。在发育过程中，肠道上皮细胞 通过一个强烈的内吞阶段，在获得成熟的肠道结构之前。我们 内毒素(EDTB)是一种高度保守的整合膜蛋白，存在于细胞内膜复合体中 发育中的肠道。在体外，EDTB调节紧密连接组装和接触介导的抑制 扩散的可能性。此外，它还与小的GTP酶Rab14结合，该酶调节 内小体和顶端质膜。然而，EDTB在发展过程中的作用是 完全未知。我们已经产生了一种肠上皮细胞特异性EDTB基因敲除小鼠， 初步数据显示，在发育早期，EDTB基因敲除会导致胚胎发育异常。 新生儿肠道包括顶端内吞复合体的丢失，顶端细胞内的积聚 质膜蛋白和异常的刷状边缘。我们将使用EDTB条件淘汰赛 小鼠，以及肠样培养和细胞系，以确定这些变化的机制基础 在上皮性分化中。我们将定义与紧密连接蛋白相互作用的机制和 定义协调其影响的EDTB的领域。此外，我们还将使用以下工具分析Rab14的角色 肠道肠样培养和人肠上皮细胞系。最后，我们将研究信令 已知的影响肠道分化的途径及其与EDTB和心尖细胞的相互作用 内噬菌体。总的来说，这些研究将提供对肠道细胞机制的洞察力。 发育，这对于我们理解肠道功能是必不可少的。实验完成后，这些实验 本提案中概述的将定义囊泡运输在正常生长、发育和动态平衡中的作用 肠道上皮细胞。这一基础知识将对我们对肠道的理解产生影响 这种疾病在新生儿和成人中都是如此，并可为治疗目标奠定基础。

Endocytic regulation of intestinal development The intestinal mucosa is a highly differentiated epithelial barrier that is fundamental for normal function of the intestine. Vesicular trafficking is now recognized as an essential regulator of epithelial polarity, integrity and cell differentiation, and studies in model systems have shown that endocytosis and membrane trafficking are essential for normal ontogenesis of the intestine. During development, the epithelial cells of the intestine go through an intensely endocytic stage that precedes the acquisition of mature intestinal architecture. We identified endotubin (EDTB) as a highly conserved integral membrane protein in the endocytic complex of the developing intestine. In vitro, EDTB regulates tight junction assembly and contact-mediated inhibition of proliferation. In addition, it binds the small GTPase Rab14, which regulates trafficking between endosomes and the apical plasma membrane. However the role of EDTB during development is completely unknown. We have generated an intestinal epithelial cell-specific EDTB knockout mouse and, in Preliminary Data, show that EDTB knockout early in development results in aberrant ontogenesis of the neonatal intestine, including loss of the apical endocytic complex, intracellular accumulation of apical plasma membrane proteins, and an aberrant brush border. We will use this EDTB conditional knockout mouse, together with enteroid cultures and cell lines, to identify the mechanistic basis for these changes in epithelial differentiation. We will define the mechanisms for interaction with tight junction proteins and define the domains of EDTB that mediate its effects. Also, we will analyze the role of Rab14 using intestinal enteroid cultures and human intestinal epithelial cell lines. Finally, we will examine the signaling pathways known to impact intestinal differentiation and define their interaction with EDTB and apical endosomes. Collectively, these studies will provide insight into the cellular mechanisms of intestinal development, which is essential for our understanding of intestinal function. When completed, the experiments outlined in this proposal will define the role of vesicular trafficking in normal growth, development, and homeostasis of the intestinal epithelium. This fundamental knowledge will have implications for our understanding of intestinal disease, both in neonates and adults, and could lay the groundwork for therapeutic targets.