Résumé
Objective To identify novel biomarker for diabetic nephropathy (DN) by urinary proteomic methods,and to detect the expression of E-cadherin in urine and renal tissue of patients with DN.Methods Urine samples were collected from 12 cases of type 1 diabetic nephropathy patients (T1DN),12 cases of type 2 diabetic nephropathy patients (T2DN),12 cases of nephritic syndrome patients (NS),and 12 cases of healthy Controls.Comparative proteomic approach of two-dimensional gel electrophoresis (2-DE) and mass spectrometry (MS) were employed to identify DN-related biomarker in urine samples.The differential expression of the identified biomarker in urine samples and renal biopsy specimens were detected by Western blotting and immunohistochemistry method.Results E-cadherin was identified by 2DE/MS,which was significantly up-regulated in T1DN and T2DN groups (all P ＜0.01).Western blotting confirmed the expression of E-cadherin was significantly higher in T1DN and T2DN groups than in NS and Control groups (all P＜0.01).Immunohistochemical stain showed E-cadherin was mainly expressed in the membrane and cytoplasm of renal tubular epithelial cell,and its expression was markedly decreased in DN kidneys compared with healthy Controls (P ＜ 0.05).Conclusions E-cadherin is identified as a novel DN-related biomarker,which is specifically increased in urine of DN patients.