Effect of urinary IgG from nephrotic patients on expression of macrophage migration inhibitory factor in human proximal tubular epithelial cells / 中华肾脏病杂志

ABSTRACT

Objective To investigate the effect of purified urinary IgG from patients with minimal change nephrotic syndrome and membranous nephropathy on the expression of macrophage migration inhibitory factor (MIF) in human proximal tubular epithelial cells (HK-2). Methods Proteins were precipitated from urine with (NH4)2SO4, and urinary IgG was purified by protein G column chromatography. SDS-PAGE and Western blotting were performed to analyze the urinary IgG. HK-2 cells were incubated with urinary IgG (0,0.5,1.0,2.5,5.0,10.0 mg/ml) from either minimal change nephrotic or membranous nephropathy patients. The expression of MIF mRNA was assessed by RT-PCR, and MIF protein was assessed by Western blotting. Results SDS-PAGE showed that there were four bands, which were all IgG fractions confirmed by Western blotting. The urinary IgG up-regulated the expression of MIF mRNA and protein in HK-2 cells. The expression increased in a dose-dependent manner. The expression of MIF mRNA and protein in HK-2 cells increased significantly when they were incubated with urinary IgG from membranous nephropathy patients at 1mg/ml (P