Molecular regulation of gastric epithelial renewal

胃上皮更新的分子调控

• 批准号: 6711228
• 负责人: Jason C Mills
• 金额: $ 11.96万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2004
• 资助国家: 美国
• 起止时间: 2004-02-01 至 2008-12-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6711228
• 关键词: Drosophilidae; binding proteins; cell differentiation; cell growth regulation; cell line; cell proliferation; electron microscopy; gastrointestinal epithelium; gene expression profiling; genetic promoter element; genetically modified animals; immunocytochemistry; immunoprecipitation; in situ hybridization; insulinlike growth factor; laboratory mouse; messenger RNA; microarray technology; protein localization; stem cells

DESCRIPTION (provided by applicant): The gastric epithelium of mice and humans undergoes continuous renewal. Dysregulated proliferation is a common feature not only of gastric disease but of orally administered medication in general. Yet little is known about the molecular mechanisms that coordinate division, differentiation, and migration of gastric epithelial cells. The goal of the current proposal is to build on previous work that determined a global gene expression profile for both the gastric epithelial progenitor cell (GEP) and the acid-secreting parietal cell (PC), a differentiated gastric lineage that is thought to regulate GEP differentiation and division. GEPs preferentially express both the critical somatic growth regulating gene insulin-like growth factor I (IGF-I) and its receptor (IGF-Ir), whereas PCs are enriched for expression of the IGF-sequestering gene IGF binding protein 2 (IGFBP2). The first aim of the current proposal is to test the hypothesis that PCs use IGFBP2 to control bioavailability of IGFs thereby regulating GEP proliferation. Mice will be generated whose parietal cells will exhibit transgenic forced expression of IGFBP2. In parallel, IGFBP2 will be conditionally ablated by generating mice with floxed IGFBP2 alleles and crossing these to mice with PC-specific expression of cre recombinase that have already been generated in the lab. Earlier work also revealed that >20% of the genes in the GEP expression profile are involved in mRNA processing; many have Drosophila homologs critical for polarity establishment and cell fate determination during embryogenesis. The second aim of the proposal will be to characterize the role of RNA localization in gastric epithelial renewal. Tools will be developed to assess the subcellular location of 1) RNA localizing proteins (e.g., Mago-m and Y14, genes in the GEP expression profile); 2) mRNA species associated with the RNA localizing apparatus. To identify candidate localized mRNAs, antibodies against RNA localizing proteins will be used to immunoprecipitate all associated mRNAs and determine their identity by oligonucleotide array. In Drosophila, genes whose RNAs are localized (e.g., runt and hairy and various genes encoding homeodomains) are critical for differentiating cell fate of daughter cells in developing tissues. Identifying localized transcripts in the gastric epithelium may lead to a better molecular picture of how normal renewal occurs in adult mammalian tissue, which, in turn, would help us better characterize both the gastric epithelial injury response and, eventually, how neoplastic (i.e. abnormal) proliferation develops and might be prevented.

描述（由申请人提供）： 小鼠和人类的胃上皮经历持续更新。增殖失调不仅是胃疾病的共同特征，也是一般口服药物的共同特征。然而，很少有人知道的分子机制，协调分裂，分化和迁移的胃上皮细胞。目前的建议的目标是建立在以前的工作，确定了全球基因表达谱的胃上皮祖细胞（GEP）和泌酸壁细胞（PC），分化的胃谱系，被认为是调节GEP分化和分裂。GEP优先表达关键的体细胞生长调节基因胰岛素样生长因子I（IGF-I）及其受体（IGF-Ir），而PC富集IGF螯合基因IGF结合蛋白2（IGFBP 2）的表达。本发明的第一个目的是检验PC使用IGFBP 2来控制IGF的生物利用度从而调节GEP增殖的假设。将产生小鼠，其壁细胞将表现出IGFBP 2的转基因强制表达。平行地，IGFBP 2将通过产生具有floxed IGFBP 2等位基因的小鼠并将这些小鼠与已经在实验室中产生的具有cre重组酶的PC特异性表达的小鼠杂交来条件性地消融。早期的工作还揭示了GEP表达谱中>20%的基因参与mRNA加工;许多基因具有果蝇同源物，这些同源物对胚胎发生期间的极性建立和细胞命运决定至关重要。该提案的第二个目的是描述RNA定位在胃上皮更新中的作用。将开发工具来评估1）RNA定位蛋白（例如，Mago-m和Y14，GEP表达谱中的基因）; 2）与RNA定位装置相关的mRNA种类。为了鉴定候选定位mRNA，将使用针对RNA定位蛋白的抗体来免疫沉淀所有相关mRNA，并通过寡核苷酸阵列确定其身份。在果蝇中，其RNA被定位的基因（例如，侏儒和多毛以及编码同源结构域的各种基因）对于分化发育组织中的子细胞的细胞命运至关重要。识别胃上皮中的本地化转录物可能会导致更好的分子图像，正常更新如何发生在成年哺乳动物组织中，这反过来又将帮助我们更好地表征胃上皮损伤反应，并最终如何肿瘤（即异常）增殖发展和可能被预防。