Synergistic effect of transforming growth factor-β1 and epidermal growth factor on transdifferentiation of human tubular epithelial cells in vitro

Objective To examine whether there is a synergism of transforming grouth factor β1 (TGF β1) and epidermal grouth factor (EGF) in inducing transdifferentiation of human tubular epithelial cell line (HKC) Methods HKC cells were divided into different groups: (1) serum free(negative control); (2) EGF (10, 20, 40 ng/ml) treated; (3) TGF β1 (3, 10, 20 ng/ml) treated; (4) EGF (10, 20, 40 ng/ml) plus TGF β1 (3, 10, 20 ng/ml) treated The cells were typically incubated for 48 hours after addition of cytokines HKC was detected by light microscopy and electron microscopy. The expression of vimentin and cytokeratin were assessed by indirect immunoflourescence, the expressions of E cadherin and α smooth muscle actin (α SMA) of HKC cells were assessed by indirect immunohistochemical double staining. The persentages of α SMA(+) HKC cells were assessed by flow cytometry Results EGF at 10, 20, 40 ng/ml or TGF β1 at 3 ng/ml did not induce visible transdifferentiation of HKC TGF β1 at 10, 20 ng/ml induced light transdifferentiation of HKC There was a synergistic effect of EGF (10, 20, 40 ng/ml) and TGF β1 (3, 10, 20 ng/ml) in induction of transdifferentiation of HKC into myofibroblasts [(35 17±2 86)%,(51 2±1 10)%,(55 43±1 15)% vs (3 53±0 09)%, P 0 05] Conclusion There is a synergism of EGF and TGF β1 at the given concentrations on transdifferentiation of HKC into myofibroblasts