PKB/Akt和GSK-3β在抗体介导的慢性排斥反应患者移植肾小管上皮细胞转分化中的作用

目的:观察磷酸化蛋白激酶B(p-Akt)、糖元合成激酶(GSK-3β)在抗体介导的慢性排斥反应(chronic active antibody-mediated reiection,ABMR)患者移植肾肾小管上皮细胞中的表达,探讨二者在移植肾小管上皮细胞转分化(EMT)中的作用。方法:38例移植肾穿刺标本经病理明确诊断为ABMR,按Banff 2009标准将其按间质纤维化/小管萎缩(IF/TA)程度Ⅰ、Ⅱ、Ⅲ级分为C1(n=12)、C2(n=14)、C3(n=12)组,用免疫组织化学技术和计算机真彩色图像分析系统半定量检测移植肾组织中p-Akt、GSK-3β、转化生长因子TGF-β_1、整合素连接激酶ILK、上皮细胞E-钙黏蛋白(E-cadherin)和α-平滑肌肌动蛋白(α-SMA)在各组中的表达面积,线性相关分别分析p-Akt、GSK-3β与转化生长因子TGF-β_1、整合素连接激酶ILK、E-cadherin和α-SMA表达的相关性及其与IF/TA病理分级之间的关系。9例正常肾组织作为对照组。结果:ABMR患者移植肾组织中p-AKt、GSK-3β、TGF-β_1、ILK和α-SMA的表达比正常肾组织明显增加(P <0. 001),并随(IF/TA)病理分级呈逐渐递增的趋势。E-钙黏蛋白在ABMR肾小管上皮细胞中的表达比正常肾组织明显减少(P <0. 001),组间呈递减趋势,移植肾组织中P-akt的表达与TGF-β_1、ILK和α-SMA呈正相关(r分别为0. 912、0. 871和0. 878,P <0. 001),而与E-cadherin的表达量呈负相关(r=-0. 849,P <0. 001);GSK-3β的表达与TGF-β_1、ILK、p-Akt和α-SMA呈正相关(r分别为0. 874、0. 793、0. 828、0. 781,P <0. 001),与E-cadherin的表达量呈负相关(r=-0. 781,P <0. 001)。p-Akt、GSK-3β、ILK、TGF-β_1和α-SMA的表达均与移植IF/TA程度呈正相关(r分别为0. 943、0. 863、0. 907、0. 964和0. 926,P <0. 001);而E-cadherin的表达与移植肾IF/TA程度成负相关(r=-0. 859,P <0. 001)。结论:P-Akt、GSK-3β作为TGF-β_1及ILK的重要下游细胞因子可能介导了ABMR所致的肾小管上皮细胞-肌成纤维细胞转分化的发生、发展,p-Akt和GSK-3β在ABMR所致移植肾间质纤维化进程中可能发挥重要作用。

Effect of PKB/Akt and GSK-3βon Renal Tubular Epithelial Cell Transdifferentiation in Chronic Active Antibody-mediated Rejection

Objective:To investigate the expression of protein kinase B(PKB/Akt)and GSK-3βin the renal allografts of patients with chronic active antibody-mediated rejection(ABMR)and its relevance with the tubular epithelial-myofibroblast transdiferentiation.Methods:Overall,38 puncture samples from renal grafts were diagnosed as ABMR by pathologic study.And IF/TA gradeⅠ、Ⅱ、Ⅲwas subdivided into groups C1(n=12),C2(n=14)and C3(n=12)by“Banff 2009”classification.9 specimens of healthy renal tissue were used as controls.Immunohistochemical assay and computer-assisted genuine colored image analysis system were used to semi-quantitative detect the expression of integrin-linked kinase(ILK),transforming growth factor-β1(TGF-β1),P-Akt,Glycogen synthase kinase 3β(GSK-3β),E-cadherin andα-smooth muscle actin(α-SMA)in the renal allografts of patients with ABMR.The correlation between P-Akt,GSK-3β,ILK,TGF-β1 and E-cadherin,α-SMA,as well as the relationship between their expressions and the pathological grading of ABMR,was analyzed.Results:The expressionlevels of p-AKT,GSK-3β,ILK,TGF-β1 andα-SMA were significantly higher in the renal tissues of the patients,compared to normal renal tissues(P<0.001),and the expressions tended to increase with the pathological grades of ABMR.The expression of E-cadherin were significantly lower in the renal tissues of the patients,compared to normal renal tissues(P<0.001),tended to decrease with the pathological grades of ABMR.In ABMR group,the expression of p-AKT was positively correlated with that of ILK,TGF-β1 andα-SMA(r=0.912、0.871 and 0.878,respectively;P<0.001 for both),while it was negatively correlated with that of E-cadherin(r=-0.849,P<0.001).the expression of GSK-3βwas positively correlated with that of ILK,p-AKT,TGF-β1 andα-SMA(r=0.874、0.793、0.828 and 0.781,respectively;P<0.001 for both),while it was negatively correlated with that of E-cadherin(r=-0.781,P<0.001).A significant positive correlation was found between the expression of p-AKT,GSK-3β,ILK,TGF-β1,α-SMA in renal interstitial tissue with ABMR and the pathological grading of ABMR(r=0.943、0.863、0.907、0.964 and 0.926,P<0.001).A significant negative corelation was also found between the expression of E-cadherin and the pathological grading of ABMR(r=-0.859,P<0.001).Conclusion:Renal tubular epithelial cell myofibroblast transdifferentiation plays an important role in the occurence and development of ABMR.p-AKT,GSK-3βas important downstream cytokines of TGF-β1 and ILK.P-aktAkt and GSK-3beta may mediate the occurrence and development of renal interstitial fibrosis induced by ABMR.