Effects of ursolic acid on interleukin-33 expression in HaCaT cells induced by interferon-γ / 中华皮肤科杂志

ABSTRACT

Objective To evaluate effects of ursolic acid (UA) on interleukin?33 (IL?33) expression in HaCaT cells induced by interferon?γ(IFN?γ), and to explore their mechanism. Methods Some HaCaT cells were treated with UA at different concentrations(0, 0.1, 1, 5, 10, 20, 40 and 80μmol/L)for 24, 48 and 72 hours separately. Then, methyl thiazolyl tetrazolium(MTT)assay was conducted to evaluate cell proliferative activity. A cell model of inflammation was established by culture of HaCaT cells with the presence of 200μg/L IFN?γ. Some HaCaT cells were classified into several groups to be treated with IFN?γ(200μg/L)and UA(10 and 15μmol/L)alone or in combination (firstly treated with IFN?γ followed by UA treatment), and those receiving no treatment served as the blank control group. Reverse transcription PCR (RT?PCR) was performed to detect mRNA expressions of IL?6 and IL?33, and Western?blot analysis to measure IL?33 protein expression after 12?hour culture. The expressions of extracelluar signal?regulated kinase 1/2(ERK1/2)and phosphorylated ERK1/2(p?ERK1/2)were also measured by Western?blot analysis after 5?and 60?minute treatments with IFN?γand UA alone or in combination. Results MTT assay showed that the treatments with 5-20μmol/L UA for 24 hours had no effects on cell proliferative activity, while 40-80μmol/L UA could significantly inhibit it at 24, 48 and 72 hours (all P 0.05), while IL?33 protein expression was significantly lower in the IFN?γ+15?μmol/L UA group than in the IFN?γ+10?μmol/L UA group(P<0.05). The p?ERK1/2 protein expression significantly increased in HaCaT cells treated with IFN?γ for 5 and 60 minutes compared with the blank control group, but significantly decreased in the IFN?γ+15?μmol/L UA group compared with the IFN?γgroup(0.458 ± 0.053 vs. 0.941 ± 0.042 at 5 minutes, 0.302 ± 0.054 vs. 0.509 ± 0.032 at 60 minutes, both P < 0.05). However, no significant differences were observed in the total ERK1/2 protein expression between the IFN?γ+15?μmol/L UA group and IFN?γgroup at 5 or 60 minutes. Conclusion UA can suppress IL?33 expression in HaCaT cells induced by IFN?γ, likely by regulating expressions of the ERK signaling pathway?related proteins.