The effect of connective tissue growth factor on human renal tubular epithelial cell transdifferentiation.

To investigate the role of connective tissue growth factor (CTGF) in transdifferentiation of human renal tubular epithelial cell (HKC), in vitro cultured HKC cells were divided into 3 groups: negtive control, low dose CTGF-treated group (rh CTGF, 2.5 ng/ml) and high dose CTGF-treated (rhCTGF, 5.0 ng/ml). Then the expression of alpha-smooth muscle actin (alpha-SMA) were assessed by indirect immuno-fluorescence, and the percentage of alpha-SMA positive cells were assessed by flow cytometry. RT-PCR were also performed to examine the mRNA level of alpha-SMA. Upon the stimulation of different concentrations of rhCTGF, the expression of alpha-SMA were markedly stronger than that in negative controls. The percentages of alpha-SMA positive cells were significantly higher in the stimulated groups than that of negative controls (38.9%, 65.5% vs 2.4%, P<0.01). alpha-SMA mRNA levels were also up-regulated by the stimulation of rhCTGF (P<0.01). These results suggest that CTGF can promote the transdifferentiation of human renal tubular epithelial cells towards myofibroblast (Myo-F).