TY - JOUR
T1 - Functional significance of CYP2B6 gene rare allelic variants identified in Japanese individuals
AU - Yamazaki, Shuki
AU - Hishinuma, Eiji
AU - Suzuki, Yuma
AU - Ueda, Akiko
AU - Kijogi, Caroline
AU - Nakayoshi, Tomoki
AU - Oda, Akifumi
AU - Saito, Sakae
AU - Tadaka, Shu
AU - Kinoshita, Kengo
AU - Maekawa, Masamitsu
AU - Sato, Yu
AU - Kumondai, Masaki
AU - Mano, Nariyasu
AU - Hirasawa, Noriyasu
AU - Hiratsuka, Masahiro
N1 - Publisher Copyright:
© 2024 The Author(s)
PY - 2024/11
Y1 - 2024/11
N2 - Cytochrome P450 2B6 (CYP2B6) catalyzes the metabolism of many drugs, including efavirenz and propofol. Genetic polymorphisms in CYP2B6 alter its enzymatic activity and substantially affect its pharmacokinetics. High-frequency variants, such as CYP2B6*6, are associated with the risk of developing side effects due to reduced CYP2B6 activity. However, the impact of rare alterations on enzyme function remains unknown, and some of these variants may significantly decrease the CYP2B6 activity. Therefore, in this study, we evaluated in vitro the functional alterations in 29 missense variants of the CYP2B6 gene identified in 8,380 Japanese individuals. Wild-type CYP2B6 and 29 rare CYP2B6 variants were transiently expressed in mammalian cells. The expression levels of variant CYP2B6 proteins in the microsomal fractions extracted from 293FT cells were assessed using western blotting and reduced-carbon monoxide difference spectroscopy, and a specific peak at 450 nm was detected in the wild-type and 19 variants. Furthermore, kinetic parameters were determined by assaying the reactions with efavirenz and propofol and quantifying the metabolite concentrations. We found that 12 variants had significantly lower or abolished enzymatic activity with both the substrates. In silico three-dimensional docking and molecular-dynamics simulations suggested that these functional changes were due to conformational changes in essential regions, such as the heme-binding site and ligand channels involved in transporting substrates to the active site. These findings have implications for predicting the plasma concentrations of CYP2B6 substrates and controlling their side effects.
AB - Cytochrome P450 2B6 (CYP2B6) catalyzes the metabolism of many drugs, including efavirenz and propofol. Genetic polymorphisms in CYP2B6 alter its enzymatic activity and substantially affect its pharmacokinetics. High-frequency variants, such as CYP2B6*6, are associated with the risk of developing side effects due to reduced CYP2B6 activity. However, the impact of rare alterations on enzyme function remains unknown, and some of these variants may significantly decrease the CYP2B6 activity. Therefore, in this study, we evaluated in vitro the functional alterations in 29 missense variants of the CYP2B6 gene identified in 8,380 Japanese individuals. Wild-type CYP2B6 and 29 rare CYP2B6 variants were transiently expressed in mammalian cells. The expression levels of variant CYP2B6 proteins in the microsomal fractions extracted from 293FT cells were assessed using western blotting and reduced-carbon monoxide difference spectroscopy, and a specific peak at 450 nm was detected in the wild-type and 19 variants. Furthermore, kinetic parameters were determined by assaying the reactions with efavirenz and propofol and quantifying the metabolite concentrations. We found that 12 variants had significantly lower or abolished enzymatic activity with both the substrates. In silico three-dimensional docking and molecular-dynamics simulations suggested that these functional changes were due to conformational changes in essential regions, such as the heme-binding site and ligand channels involved in transporting substrates to the active site. These findings have implications for predicting the plasma concentrations of CYP2B6 substrates and controlling their side effects.
KW - CYP2B6
KW - Cytochrome P450
KW - Drug metabolism
KW - Genetic polymorphisms
KW - Pharmacogenomics
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U2 - 10.1016/j.bcp.2024.116515
DO - 10.1016/j.bcp.2024.116515
M3 - Article
C2 - 39218044
AN - SCOPUS:85202755389
SN - 0006-2952
VL - 229
JO - Biochemical Pharmacology
JF - Biochemical Pharmacology
M1 - 116515
ER -