ABSTRACT
Objective To observe the expressions and distribution of transient receptor potential cation channel 6 (TRPC6) and integrin-linked kinase (ILK) in the glomeruli of renal biopsytissue of patients with proteinuric kidney diseases,and to investigate the effect of TRPC6 over-expression on ILK in vitro.Methods The archival histological specimens of patients admitted to Tangdu hospital from 2012 to 2013,with 24-hour urinary protein over 1 g,were collected.The expressions and distribution of TRPC6 and ILK in the glomeruli of renal biopsy tissue were observed by immunohistochemistry.MPC5 podocytes were cultured in vitro and they were stimulated with 10-7 mol/L ADR for 12,24 and 36 h.The pcDNA3.1(+)-TRPC6 plasmid and pcDNA3.1(+) were transfected into MPC5 podocytes by liposome 2000 reagent to establish the TRPC6 overexpression group and the negative control group respectively.Western blotting was used to detect the expressions of TRPC6 and ILK protein.Results There were 14 cases of membranous nephropathy,13 cases of focal segmental glomerulosclerosis (FSGS),15 cases of membranoproliferative glomerulonephritis,12 cases of mesangial proliferative glomerulonephritis,10 cases of hyperplastic sclerosis nephritis,15 cases of IgA nephropathy,13 cases of purpura nephritis,15 cases of lupus nephritis,13 cases of hypertensive renal injury,14 cases of diabetic nephropathy and 9 cases of normal renal tissue included.In glomerulus,TRPC6 was expressed mainly in podocytes,and the expressions of TRPC6 in these renal tissues were higher than that in normal renal tissues (all P ＜ 0.05),except for hypertensive nephropathy.ILK was expressed in podocytes and the mesangial areas.The expressions of ILK in FSGS,lupus nephritis and diabetic nephropathy were higher than that in normal kidney tissue (all P ＜ 0.05),while the other renal tissues was high but showed no statistical difference with normal kidney tissue (all P ＞ 0.05).The expressions of TRPC6 and ILK were positively correlated in renal tissues of FSGS and diabetic nephropathy (r=0.906,P ＜ 0.001;r=0.783,P=0.001 respectively).The expressions of TRPC6 and ILK protein in 24 and 36 h stimulating with ADR were significantly higher than that in the control group (all P ＜ 0.05).The expression of ILK in the TRPC6 overexpression group was significantly higher than that in the normal control group (P ＜ 0.05).Conclusions The expressions of TRPC6 and ILK increase in the glomeruli of patients with kidney diseases with proteinuria being the main manifestation,especially in FSGS and diabetic nephropathy.The up-regulation of TRPC6 can increase the expression of ILK protein,which may be involved in podocyte injury.