醛固酮对UT—A1和UT—A3蛋白表达及其尿素转运活性的影响  

Effects of aldosterone on the protein expressions and the urea transport activity of UT-A1 and UT- A3

作　　者：胡云霞[1] 梁海燕[1] 庄捷秋[1] 陈敏广[1] Hu Yunxia;Liang Haiyan;Zhuang Jieqiu;Chen Minguang.(Department of Nephrology, the Second Affiliated Hospital of Wenzhou Medical University, Yuying Children＇s Hospital, Wenzhou 325027, Chin)

机构地区：[1]温州医科大学附属第二医院育英儿童医院儿童肾内科,325027

出　　处：《中华肾脏病杂志》2018年第3期201-207,共7页Chinese Journal of Nephrology

基　　金：浙江省自然科学基金项目（LY18H050006）;温州市科技局基金项目（Y20150022）

摘　　要：目的研究醛固酮对体外培养HEK293细胞及非洲爪蟾卵母细胞尿素转运子Al（UT-A1）和尿素转运子Al（UT—A3）蛋白表达及尿素转运活性的影响。方法（1）应用Western印迹检测醛固酮对UT-A1、UT-A3总蛋白在HEK293细胞中表达的影响。（2）应用细胞表面生物素化及Western印迹检测醛固酮对UT-A1、UT-A3在非洲爪蟾卵母细胞的总蛋白及细胞膜表达的影响。（3）应用14C-尿素转运试验检测醛固酮对高表达UT-A1、UT—A3的非洲爪蟾卵母细胞尿素转运活性的影响。结果（1）Western印迹结果显示，与对照组相比，醛固酮组UT—A1总蛋白水平下降（P〈0．01），UT-A3总蛋白水平下降（P〈0．01）。（2）细胞表面生物素化结果显示，与对照组相比，醛固酮组UT-A1蛋白在细胞膜的表达水平和在总蛋白中的水平均下降（均P〈0．01），UT—A3蛋白在细胞膜的表达和在总蛋白中的表达水平均下降（均P〈0．01）。（3）14C-尿素转运试验结果显示，与UT-A1高表达组相比，醛固酮组UT-A1尿素转运活性下降（1min：94．32±9．044比40．68±4．274，P〈0．01，n=6；3min：165．0±4．74比80．3±0．60，p〈0．01，n=6），与UT—A3高表达组相比，醛固酮组UT—A3尿素转运活性下降（1min：204．6±3．12比176．7±9．1，P〈0．05，n=6；3min：371．4±14．9比318．8±12．0，P〈0．05，n=6）。结论醛固酮能直接下调UT-A1蛋白和UT—A3蛋白在总蛋白及膜蛋白中的表达、降低其尿素转运活性从而参与尿液的浓缩和稀释过程。Objective To investigate the effects of protein expressions and the urea transport activity of aldosterone on urea transporter A1 （UT-A1） and urea transporter A3 （UT-A3） in HEK293 cells and Xenopus laevis oocytes. Methods （1） Western Blot was used to investigate the protein expressions of UT-A1 and UT-A3. （2） Cell surface biotinylation was used to investigate the protein expressions of UT-A1 and UT-A3 on the cell surface of Xenopus laevis oocytes. （3） 14C-urea transport experiment was conducted to investigate the transport activity of UT-A1 and UT-A3 in Xenopus laevis oocytes. Results （1） Compared with UT-A1 or UT-A3 high expression groups, the total protein levels of UT-A1 and UT-A3 were all significantly reduced in aldosterone treatment groups （all P〈 0.01）. （2） Compared with UT-A1 or UT-A3 high expression groups, the levels of protein expression on cell surface were all significantly reduced in aldosterone groups （all P 〈 0.01）. （3） Compared with UT- A1 or UT-A3 high expression groups, 14C-urea transport experiment results showed that aldosterone treatment groups had significantly reduced the urea transporter activity of UT-A1 （1 min： 94.32±9.044 vs 40.68±4.274, P 〈 0.01, n=6; 3 rain： 165.0±4.7 vs 80.3±0.6, P〈 0.01, n=6）, and UT-A3 （1 min： 204.6 ± 3.1 vs 176.7 ± 9.1, P〈0.05, n=6; 3 min： 371.4 ± 14.9 vs 318.8 ± 12.0, P〈0.05, n=6）. Conclusion Aldosterone can directly down-regulate the protein expressions of UT-A1 and UT-A3 in both total protein and cell surface level, which reduces their urea transport activity.

关 键 词：醛固酮 膜转运蛋白质类 尿 尿素转运子A1 尿素转运子A3 

分 类 号：R692[医药卫生—泌尿科学]