Genetic polymorphisms of the drug-metabolizing enzymeCYP2C19in the Uyghur population in northwest China

Mechanistic study of cytochrome P450 enzyme-mediated cytotoxicity of psoralen and isopsoralen

Psoralen and isopsoralen are the major components responsible for Psoraleae Fructus-induced hepatotoxicity. This study explored the role of metabolic activation by cytochrome P450 (CYP) enzymes in psoralen- and isopsoralen-induced cytotoxicity and its potential mechanisms. Inhibitors of CYP1A2, 2C9, 2C19, 2D6, 2E1, and 3A4 were used to screen specific CYP enzymes responsible for the metabolic activation of psoralen and isopsoralen in mouse primary hepatocytes, which was verified using the corresponding transfected cell lines. Network toxicology and transcriptome analyses were performed to explore the mechanisms underlying toxicity. Psoralen and isopsoralen decreased the viability of mouse primary hepatocytes, whereas the inhibition of CYP2C9, 2C19, 2D6, and 2E1 significantly increased their viability. Psoralen-induced cytotoxicity was significantly enhanced by the overexpression of CYP2C19 in Chinese hamster ovary cells, whereas the overexpression of the above CYP enzymes did not affect the cytotoxicity of isopsoralen. Psoralen- and isopsoralen-induced cytotoxic effects were associated with putative core targets (i.e., Fn1, Thbs1, and Tlr2) and multiple signaling pathways (e.g., PI3K-Akt, MAPK, and TNF pathways). Our results demonstrate that the metabolic activation of psoralen and isopsoralen is mediated by CYP enzymes, thereby regulating multiple core targets and signaling pathways and resulting in cytotoxicity.

CYP2C19 genetic polymorphism in the Vietnamese population

Background: Genetic polymorphism of CYP2C19 has been shown to affect enzyme activity and thereby contribute to inter-individual variability in drug metabolism and response. The complete genetic variation of CYP2C19 in Vietnam still remains obscure even though data of common alleles in Vietnamese Kinh have been reported.Aim: To establish the extent of CYP2C19 polymorphism in Vietnamese.Subjects and methods: The promoter and all nine exons of CYP2C19 in 100 healthy unrelated Vietnamese Kinh subjects were sequenced. Additionally, the CYP2C19 variants, *2, *3 and *17 were analysed by RFLP-PCR in 275 subjects of four minor ethnic groups in Vietnam (Tay, Muong, H'Mong and Nung).Results: In 100 Kinh subjects, the percentages of CYP2C19*1, CYP2C19*2, CYP2C19*3 and CYP2C19*17 alleles were 76%, 20.5%, 2.5% and 1%, respectively. Three novel variants in introns 2, 5 and 8 had no impact on mRNA splicing according to the Human Splicing Finder. The prevalence of CYP2C19*17 in Vietnamese Kinh was significantly lower compared with figures found in Western Asia and Europe, while CYP2C19*2 frequency was statistically higher than that in Western Asia and several countries in Europe. The frequency of CYP2C19*2 in Kinh was significantly lower than in the other four ethnic minorities.Conclusion: These results provide information on CYP2C19 polymorphism in the Vietnamese population, which could be useful for optimising drug therapies and precision medicine studies.