Effect of isoniazid on methylation of CYP1A1 promoter region of human hepatic cells

NIU Chen; ZHANG Yiyang; LI Jinfeng; LI Yingshu; LI Yuhong; TIAN Shenqian; WANG Yue; FENG Fumin

doi:10.3969/j.issn.1002-266X.2017.26.001

Abstract：Objective To observe the effect of isoniazid on methylation of CpG island in cytochrome P4501A1 (CYP1A1) promoter region of human hepatocytes and to explore the mechanism of isoniazid-induced hepatocyte injury.Methods Liver cells were divided into the experimental group and control group.Cells in the experimental group were treated with 200, 400, and 800 μg/mL isoniazid, respectively.Cells in the control group were added with the same volume of DMSO culture medium.The LDH level in the supernatant was measured by lactate dehydrogenase (LDH) assay kit.The relative expression of CYP1A1, DNA methyltransferase 1 (DNMT1), DNMT3a, and DNMT3b mRNA was detected by real-time fluorescent quantitative PCR.The protein levels of DNMT1, DNMT3a, and DNMT3b were detected by enzyme-linked immunosorbent assay.The methylation of CYP1A1 promoter was detected by bisulfite sequencing PCR.Results The level of LDH in the supernatant of the experimental group was higher than that in the control group, and the LDH level was the highest in the 800 μg/mL isoniazid group (all P<0.05).Compared with the control group, the expression of CYP1A1 mRNA in the experimental group first increased and then decreased with the increasing concentrations of isoniazid (all P<0.05).DNMT1, DNMT3a, and DNMT3b mRNA and protein expression increased with the increase of isoniazid concentration, and the 800 μg/mL isoniazid group was the highest (P<0.05).The methylation rate of CYP1A1 gene promoter region was 82.9%, which was higher than that of control group (79.6%) (P<0.05).Conclusion Isoniazid can cause human hepatocyte injury, and the mechanism may be related to CYP1A1 gene promoter hypermethylation.