Effects of narrow-band ultraviolet B on the expression of keratin 17 in keratinocytes / 中华皮肤科杂志

ABSTRACT

Objective To investigate the effects of narrow-band ultraviolet B (NB-UVB) on the expression of keratin 17 (K17) in the human keratinocyte cell line HaCaT.Methods Cultured HaCaT cells were irradiated with different doses (0,50,100,200,400 mJ/cm2) of NB-UVB followed by additional culture for 6,12 and 24 hours respectively.To explore the mechanisms underlying the effects of NB-UVB on K17 expression,some HaCaT cells were pretreated with PD98059 (an inhibitor of mitogen-activated protein kinase kinase) followed by UVB radiation and additional culture as described above.Cell counting kit-8 (CCK 8) was used to evaluate the proliferation of,real time PCR to measure the mRNA expressions of K17 in,and Western blot to determine the protein expression of K17,Erk1/2 and phosphorylated Erk1/2 in,HaCaT ceils.Results Both the proliferation of and K17 expression in HaCaT cells were promoted by NB-UVB radiation at low doses (50,100 mJ/cm2),but inhibited by NB-UVB radiation at high doses (200,400 mJ/cm2).Significant differences were observed for the proliferative activity between HaCaT cells irradiated with NB-UVB at 100 or 400 mJ/cm2 and unirradiated HaCaT ceils at 12 and 24 hours (P ＜ 0.01 or 0.05).The phosphorylation of Erk1/2 was upregulated by NB-UVB radiation at 100 mJ/cm2,but downregulated by that at 400 mJ/cm2,and the upregulation induced by low dose NB-UVB could be suppressed by blocking the Erk 1/2 pathway.Conclusion The effects of NB-UVB radiation on K17 expression may be modulated by the Erk 1/2 pathway.