Effects of a novel retinoic acid ECPIRM and all-trans-retinoic acid on interleukin-1β expression in interleukin-17-stimulated HaCaT cells

Objective To explore the effects of a novel retinoic acid ECPIRM and all-trans-retinoic acid (ATRA) on interleukin (IL) -1β expression in IL-17-stimulated human HaCaT keratinocytes. Methods Cultured HaCaT cells were classified into several groups: ECPIRM groups treated with 20- 320 μmol/L ECPIRM for 24-72 hours, ATRA groups treated with 1-100 μmol/L ATRA for 24-72 hours, IL-17 group treated with 20 μg/L IL-17 for 24 hours, IL-17+ECPIRM group cotreated with 20 μg/L IL-17 and 80 μmol/L ECPIRM for 24 hours, IL-17+ATRA group cotreated with 20 μg/L IL-17 and 5 μmol/L ATRA for 24 hours, control group treated with the solvent solution of IL-17. Then, methyl thiazolyl tetrazolium (MTT) assay was performed to evaluate cellular proliferative activity in these groups, enzyme-linked immunosorbent assay (ELISA) to measure the level of IL-1β protein in the culture supernatant of HaCaT cells, quantitative fluorescent PCR to detect the mRNA expression of IL-1β in HaCaT cells. Data were statistically analyzed by using one-way analysis of variance (ANOVA) followed by the least significant difference (LSD) test. Results The treatments with ECPIRM of 20 and 40 μmol/L for 24 hours could promote the proliferation of HaCaT cells. However, with the increase in treatment duration and concentrations, ECPIRM inhibited the growth of HaCaT cells in a concentration-and time-dependent manner. ATRA also decelerated the proliferation of HaCaT cells in a concentration-and time-dependent manner. The levels of supernatant IL-1β protein and intracellular IL-1β mRNA were both significantly higher in the IL-17 group than in the control group (IL-1β protein: 20.312 ± 2.053 ng/L vs. 11.427 ± 0.929 ng/L, P 0.05). Conclusion IL-17 can promote the secretion of IL-1β by HaCaT cells, while ECPIRM and ATRA can significantly inhibit the IL-17-induced IL-1β secretion. Key words: Keratinocytes; Retinoids; Interleukin-17; Interleukin-1beta; HaCaT cell; ECPIRM; ATRA