Petr Pavek1, Jan Dusek1, Tomas Smutny1, Lukas Lochman2, Radim Kucera2, Josef Skoda1, Lucie Smutna1, Rajamanikkam Kamaraj1, Pavel Soucek3,4, Radim Vrzal5, Zdenek Dvorak5. 1. Department of Pharmacology and Toxicology, Faculty of Pharmacy in Hradec Kralove, Charles University, Hradec Kralove, Czech Republic. 2. Department of Pharmaceutical Chemistry and Pharmaceutical Analysis, Faculty of Pharmacy in Hradec Kralove, Charles University, Hradec Kralove, Czech Republic. 3. Toxicogenomics Unit, National Institute of Public Health, Prague, Czech Republic. 4. Laboratory of Pharmacogenomics, Biomedical Center, Faculty of Medicine in Pilsen, Charles University, Pilsen, Czech Republic. 5. Department of Cell Biology and Genetics, Faculty of Science, Palacky University, Olomouc, Czech Republic.
Abstract
SCOPE: CYP3A4 is the most important drug-metabolizing enzyme regulated via the vitamin D receptor (VDR) in the intestine. However, less is known about VDR in the regulation of CYP3A4 and other drug-metabolizing enzymes in the liver. METHODS AND RESULTS: This study investigates whether 1α,25-dihydroxyvitamin D3 (1α,25(OH)2 D3 ) regulates major cytochrome P450 enzymes, selected phase I and II enzymes, and transporters involved in xenobiotic and steroidal endobiotic metabolism in 2D and 3D cultures of human hepatocytes. The authors found that 1α,25(OH)2 D3 increases hepatic CYP3A4 expression and midazolam 1'-hydroxylation activity in 2D hepatocytes. The results are confirmed in 3D spheroids, where 1α,25(OH)2 D3 has comparable effect on CYP3A4 mRNA expression as 1α-hydroxyvitamin D3 , an active vitamin D metabolite. Other regulated genes such as CYP1A2, AKR1C4, SLC10A1, and SLCO4A1 display only mild changes in mRNA levels after 1α,25(OH)2 D3 treatment in 2D hepatocytes. Expression of other cytochrome P450, phase I and phase II enzyme, or transporter genes are not significantly influenced by 1α,25(OH)2 D3 . Additionally, the effect of VDR activation on CYP3A4 mRNA expression is abolished by natural dietary compound sulforaphane, a common suppressor of pregnane X receptor (PXR) and constitutive androstane receptor (CAR). CONCLUSION: This study proposes that VDR or vitamin D supplementation is unlikely to significantly influence liver detoxification enzymes apart from CYP3A4.
SCOPE: CYP3A4 is the most important drug-metabolizing enzyme regulated via the vitamin D receptor (VDR) in the intestine. However, less is known about VDR in the regulation of CYP3A4 and other drug-metabolizing enzymes in the liver. METHODS AND RESULTS: This study investigates whether 1α,25-dihydroxyvitamin D3 (1α,25(OH)2 D3 ) regulates major cytochrome P450 enzymes, selected phase I and II enzymes, and transporters involved in xenobiotic and steroidal endobiotic metabolism in 2D and 3D cultures of human hepatocytes. The authors found that 1α,25(OH)2 D3 increases hepatic CYP3A4 expression and midazolam 1'-hydroxylation activity in 2D hepatocytes. The results are confirmed in 3D spheroids, where 1α,25(OH)2 D3 has comparable effect on CYP3A4 mRNA expression as 1α-hydroxyvitamin D3 , an active vitamin D metabolite. Other regulated genes such as CYP1A2, AKR1C4, SLC10A1, and SLCO4A1 display only mild changes in mRNA levels after 1α,25(OH)2 D3 treatment in 2D hepatocytes. Expression of other cytochrome P450, phase I and phase II enzyme, or transporter genes are not significantly influenced by 1α,25(OH)2 D3 . Additionally, the effect of VDR activation on CYP3A4 mRNA expression is abolished by natural dietary compound sulforaphane, a common suppressor of pregnane X receptor (PXR) and constitutive androstane receptor (CAR). CONCLUSION: This study proposes that VDR or vitamin D supplementation is unlikely to significantly influence liver detoxification enzymes apart from CYP3A4.