肿瘤坏死因子-α对肠黏膜上皮细胞谷氨酰胺载体功能及其表达的影响  

TNF-α affects the function and expression of glutamine transporter in intestinal epithelial cell line-6

作　　者：周济宏[1] 李幼生 洪志坚[1] 胡心宝[1] 解伟光[1] 于泽平 

机构地区：[1]南京军区南京总医院烧伤整形科,南京医学博士210002 [2]解放军普通外科研究所

出　　处：《医学研究生学报》2010年第8期795-799,共5页Journal of Medical Postgraduates

基　　金：国家自然科学基金(30271263)

摘　　要：目的肿瘤坏死因子-α(TNF-α)是感染中最重要的调节因子,谷氨酰胺需经过其载体转运至细胞内才能被利用。文中研究TNF-α对肠黏膜上皮细胞株(intestinal epithelial cell line,IEC)-6细胞膜谷氨酰胺载体功能、ASCT2mRNA及蛋白表达的可能影响,揭示TNF-α对细胞膜谷氨酰胺载体功能的影响机制。方法体外培养IEC-6,分为对照组(不与TNF-α共孵育)和实验组(与TNF-α共孵育):实验组与不同剂量的TNF-α(2、5、8、10ng/ml)共孵育2h后,测定细胞[3H]-L-谷氨酰胺摄取率;实验组与5ng/mlTNF-α共孵育不同时段(2、5、8、10h)后,测定ASCT2载体mRNA水平;实验组与5ng/mlTNF-α共孵育不同时段(2、6h)后,检测载体ASCT2蛋白表达水平。结果不同TNF-α剂量孵育的实验组[3H]-L-谷氨酰胺摄取率显著低于对照组(P<0.01),实验组之间差异无显著性意义(P>0.05);孵育2h的实验组ASCT2载体mRNA水平显著高于对照组(P<0.01),时间延长后逐渐下降,10h则与对照组差异无显著性意义(P>0.05);不同时段实验组载体ASCT2蛋白表达水平均显著低于对照组(P<0.01),实验组间差异无显著性意义(P>0.05)。结论TNF-α抑制IEC-6细胞膜谷氨酰胺载体的摄取功能,抑制ASCT2蛋白表达,但不抑制IEC-6细胞ASCT2载体mRNA的表达。TNF-α对细胞膜谷氨酰胺载体功能的抑制可能发生在载体蛋白的翻译或以后水平。Objective Few investigations have been reported on the relation of glutamine with its transporter,especially in sepsis,in which TNF-α is one of the major mediators.Our aim is to examine whether TNF-α affects the function of the glutamine transporter and the mRNA and protein expressions of ASCT2,and to investigate the mechanism of TNF-α affecting the function of the glutamine transporter in the intestinal epithelial cell line（IEC）.Methods Rat IEC-6 were incubated in vitro and randomly assigned into a control group（incubated without TNF-α） and an experimental group（incubated with TNF-α）.The -L-glutamine uptake of glutamine was measured after incubated with TNF-α at 2,5,8 and 10 ng/ml for 2 hours,the mRNA expression of ASCT2 detected after incubated with TNF-α at 5 ng/ml for 2,5,8 and 10 hours,and the protein expression of ASCT2 determined after incubated with TNF-α at 5 ng/ml for 2 and 6 hours.Results The -L-glutamine uptake of glutamine was significantly lower in the experimental group than in the control（P〈0.01）.The mRNA expression of ASCT2 was evidently increased after incubated with TNF-α for 2 hours（P〈0.01） and then gradually decreased with the lengthening of incubation time,with no statistically significant difference from the control group at 10 hours.The protein expression of ASCT2 was remarkably lower in the experimental groups than in the control（P〈0.01）,but with no significant difference between the two experimental groups（P〉0.05）.Conclusion TNF-α inhibits the glutamine transporter from uptaking glutamine and suppresses the protein expression,but not the mRNA expression of ASCT2.Thus,the inhibition of TNF-α on the glutamine transporter might occur at or after protein translation.

关 键 词：肿瘤坏死因子-Α [3H]-L-谷氨酰胺 肠黏膜上皮细胞株 谷氨酰胺载体 ASCT2 

分 类 号：R392.11[医药卫生—免疫学]