Key Laboratory of Cancer Proteomics of Chinese Ministry of Health, Xiangya Hospital, Central South University, Changsha 410008, China.
J Proteome Res. 2010 Mar 5;9(3):1416-23. doi: 10.1021/pr9009386.
The aging process of human colonic epithelium involves a slow decline in physiological vigor and an increasing susceptibility to age-related diseases, especially, colon cancer, but the mechanisms still remain to be elucidated. To reveal the molecular bases of colonic epithelial aging, a proteomic approach was used to screen for differential proteins in the human normal colonic epithelial tissues from young and old people. As a result, 17 differential proteins were identified by two-dimensional electrophoresis and mass spectrometry, and the partial differential proteins were confirmed by immunohistochemistry. Rack1, EF-Tu and Rhodanese, three validated differential proteins, were further investigated for their role in the in vitro cell senescence. Western blot showed that the expression of all the three proteins was downregulated in the senescent NIH/3T3 cells induced by D-galactose as compared to the control cells. Furthermore, knockdown of Rack1 by siRNA could promote NIH/3T3 cell senescence. Taken together, our results suggest that Rack1, EF-Tu and Rhodanese are aging-related proteins in human colonic epithelium, and injury of mitochondrial function and decline of antioxidant capability are important reasons for the aging of human colonic epithelium.
人类结肠上皮的衰老过程涉及生理活力的缓慢下降和对与年龄相关疾病（尤其是结肠癌）的易感性增加，但机制仍有待阐明。为了揭示结肠上皮衰老的分子基础，我们采用蛋白质组学方法筛选来自年轻人和老年人的正常结肠上皮组织中的差异蛋白。结果，通过二维电泳和质谱鉴定出 17 种差异蛋白，并通过免疫组织化学进一步验证了部分差异蛋白。经过验证的 3 种差异蛋白 Rack1、EF-Tu 和 Rhodanese 进一步研究了它们在体外细胞衰老中的作用。Western blot 显示，与对照组细胞相比，D-半乳糖诱导的衰老 NIH/3T3 细胞中这 3 种蛋白的表达均下调。此外，通过 siRNA 敲低 Rack1 可促进 NIH/3T3 细胞衰老。综上所述，我们的研究结果表明，Rack1、EF-Tu 和 Rhodanese 是人结肠上皮中的衰老相关蛋白，线粒体功能损伤和抗氧化能力下降是人结肠上皮衰老的重要原因。
