人结肠上皮衰老相关蛋白质的筛选

Identification of aging related proteins in human normal colonic epithelium

目的:筛选与人结肠上皮衰老相关的蛋白质以探讨人结肠上皮衰老及对癌症易感的分子机制。方法:应用双向凝胶电泳技术分离青年人及老年人的正常结肠上皮的总蛋白,经银染显色、图像分析、识别差异表达的蛋白质点,应用基质辅助激光解吸电离飞行时间质谱得到相应的肽质量指纹图谱,搜索数据库鉴定部分差异蛋白质点。结果:建立了青年人和老年人的正常结肠上皮的双向凝胶电泳图谱,质谱鉴定得到青年人和老年人之间的表达差异大于2倍的蛋白质点19个,包括17种非冗余蛋白质,它们的功能涉及物质代谢、能量产生、物质转运、抗氧化以及蛋白质的翻译、修饰和折叠等。结论:筛选并鉴定了17种结肠上皮衰老相关的蛋白质,提示线粒体功能受伤、抗氧化能力下降是结肠上皮衰老的重要原因,为揭示结肠上皮的衰老机制及衰老的结肠上皮对癌症易感的机制提供了线索。

Objective To explore the molecular mechanisms of colonic epithelial aging related proteins and aged colonic epithelial susceptibility to tumor. Methods The proteins of normal human colonic epithelial tissue from young and old people were separated by 2-dimensional gel electrophoresis （2DGE）, respectively. Then gels were stained by silver, scanned by imagescanner and analyzed with PDQuest software. The differentially expressed protein spots of colonic epithelium between the old and the young groups were identified by peptide mass fingerprint based on matrix-assisted laser desorption/ionization time of flight mass spectrometry （MALDI-TOF-MS） and database searching. Results Well-resolved and reproducible 2DGE maps of normal human colonic epithelium from the young and the old were ac- quired. Nineteen more than 2 fold differentially expressed protein spots were identified representing 17 different proteins by MALDI-TOF-MS. The functions of these proteins involve in metabolism, energy generation, transportation, antioxidation, translation and protein folding. Conclusion Seventeen aging related proteins of human colonic epithelium identified indicate that injury of mitochondrial function and decline of antioxidant capability are important reasons for the aging of human colonic epithelium. These data provided useful clues for elucidating the mechanisms of colonic epithelial aging and aged colonic epithelial susceptibility to cancer.