Abstract:

Objective To investigate the effect of tacrolimus on the expression of nuclear factor-κB （NF-κB） in HaCaT cells stimulated by tumor necrosis factor-α （TNF-α）, and on the expression of glucocorticoid receptor （GR） α and β in untreated HaCaT cells in vitro. Methods Cultured HaCaT cells were treated with TNF-α （10 μg/L） only, combination of TNF-α （10 μg/L） and various concentrations （10-8 mol/L, 10-7 mol/L, 10-6 mol/L）of tacrolimus, or tacrolimus of different concentrations only. After additional 12-, 24-, 36- or 48-hour culture, Western blot and immunofluorescence-confocal laser scanning microscopy were used to detect the expressions of NF-κB, GRα and GRβ in HaCaT cells. Those untreated HaCaT cells served as the control. Results The relative protein expression level of NF-κB was increased in HaCaT cells after treatment with TNF-α for 24 and 48 hours compared with untreated cells （0.73 ± 0.0316 and 0.8925 ± 0.0171 vs 0.4988 ± 0.03506, both P < 0.05）; however, the increase in NF-κB expression was inhibited by the combination treatment with tacrolimus, and the relative expression level of NF-κB protein was 0.6825 ± 0.0263, 0.6200 ± 0.0163 and 0.5575 ± 0.0299 in HaCaT cells treated with TNF-α plus tacrolimus of 10-8 mol/L, 10-7 mol/L and 10-6 mol/L, respectively; the difference was significant between TNF-α-treated cells and those dealt with the combination of TNF-α and tacrolimus of 10-7 or 10-6 mol/L （both P < 0.05）. No significant difference was observed in the expression of NF-κB by HaCaT cells between different time points treated with tacrolimus of 10-8, 10-7 or 10-6 mol/L. Also, there was no significant difference in the expression of GRα or GRβ between untreated HaCaT cells and those treated with tacrolimus of 10-8, 10-7 or 10-6 mol/L at any time point. Conclusions Tacrolimus could inhibit the expression of NF-κB by TNF-α-stimulated HaCaT cells, but does not affect the expression of GRα or GRβ, in untreated HaCaT cells.

Key words: Tacrolimus, Keratinocytes, NF-kappa B, Receptors, glucocorticoid, HaCaT cells