EPITHELIAL CHANGE/GENE EXPRESSION IN CROHN'S DISEASE

肠上皮是粘膜免疫系统和肠腔环境之间的主要界面。SAMP1/Yit小鼠是一种遗传近交系小鼠，在30周大时会患上类似于人类克罗恩病的回肠炎，几乎完全外露。SAMP/Yit小鼠疾病的一个主要特征是回肠上皮明显的结构异常，发生在炎症和回肠炎的早期。回肠炎在无菌SAMP/YIT中不发生，提示肠腔细菌或环境造成的上皮损伤在慢性回肠炎的发生中起作用。这些观察结果提出了一种假设，即SAMP1/Yit小鼠对损伤的上皮反应发生了变化，这会导致异常，进而导致慢性伊肠炎。目的1将检测SAMP/Yit小鼠与对照小鼠相比，是否对上皮损伤有不同的反应。我们将研究上皮干细胞命运之间的关系。过继转移技术将被用来分离SAMP1/Yit上皮固有的损伤反应与由激活的T细胞和炎症反应引起的变化的差异。还将检测调节隐窝上皮细胞凋亡的基因表达的变化。在目标2中，我们将确定SAMP/Yit小鼠体内存在的上皮结构或分化的变化是否会导致调节炎症反应的分子的上皮产生的变化。上皮源性细胞因子的产生将在从患有回肠炎的小鼠的n个上皮细胞中分离出来，并从上皮细胞特性的可遗传变化中检测。在目标3中，我们将检查上皮表达基因的可遗传差异，这些基因可能参与SAMP/Yit小鼠回肠炎的发展。这将使用cDNA微阵列技术来识别差异表达的基因，这些基因是通过项目2中概述的遗传分析确定的与疾病易感性或疾病发展有关的染色体位点编码的。

The intestinal epithelium represents the major interface between the mucosal immune system and the lumenal environment. The SAMP1/Yit mouse is a genetically inbred mouse line that develops ileitis that is similar to human Crohn's disease with near complete penetrance by 30 weeks of age. A major feature of disease in the SAMP/Yit mouse is the prominent architectural abnormalities of the ileal epithelium that occur early in the development of inflammation and ileitis. Ileitis does not develop in germ free SAMP/Yit suggesting a role for lumenal bacteria or environmentally-produced epithelial damage in the development of chronic iteal inflammation. These observations raise the hypothesis that SAMP1/Yit mice have an altered epithelial response to injury which results in abnormalities which, in turn, leads to chronic iteal inflammation. Aim 1 will examine whether SAMP/Yit mice have an altered response to epithelial damage compared to control mice. The relationship of epithelial stem cell fate will be examined. Adoptive transfer techniques will be used to separate differences in injury-response that are intrinsic to the SAMP1/Yit epithelium from changes induced by the presence of activated T-cells and an inflammatory response. Changes in the expression of genes which regulate crypt epithelial apoptosis will also be examined. In aim 2 we will determine whether the changes in epithelial architecture or differentiation present in the SAMP/Yit mouse induce alterations in epithelial production of molecules that regulate the inflammatory response. The production of epithelial derived cytokines will be examined in n epithelial cells isolated from mice with ileitis and from heritable alterations in the properties of the epithelial alterations in the properties of the epithelial cells or are induced by inflammation and ongoing epithelial damage. In aim 3 we will examine heritable differences in epithelial expressed genes that may be involved in the development of ileitis in the SAMP/Yit mouse. This will be accomplished using cDNA microarray technology to identify differentially expressed genes that are encoded with chromosomal loci associated with susceptibility or development of disease as determined through the genetic analysis outlined in project 2.