In Vitro Study on Influences of UGT1A8 Gene Polymorphisms on Mycophenolate Mofetil Metabolism

摘要

Objectives: Mycophenolate mofetil is a first-line drug after organ transplant, but there are differences in metabolism of mycophenolate mofetil among individuals. The UDP glucuronosyltransferase enzyme is the key metabolic enzyme for mycophenolate mofetil, and UGT1A8 gene polymorphisms may affect the elimination of mycophenolate mofetil in patients. Here, we conducted an in vitro study to explore the relation between UGT1A8 gene polymorphisms and mycophenolate mofetil metabolism. Materials and Methods: Five mutant loci overex-pression vectors (UGT1A8 128CT, 157CA, 431CT, 518CG, and 830GA) were constructed by genetic recombination and site-directed mutagenesis. We used Lipo2000 (Invitrogen, Carlsbad, CA, USA) to transfect the vectors into HEK293 cells. Mycophenolic acid, the active ingredient of mycophenolate mofetil, was added to different groups of cells. We then used the liquid chromatography tandem-mass spectro-metry technique to detect production of the metabolite 7-O-mycophenolic acid glucuronide and to evaluate activity of the UDP glucuronosyltransferase enzyme in cells with different overexpression vectors. Results: Mutations of UGT1A8 157CA and 518CG vectors can lead to increased activity of UDP glucuronosyltransferase enzymes and increased production of the 7-O-mycophenolic acid glucuronide metabolite, which showed 116% (P P = .0191) production changes of 157CA and 518CG mutations, respectively, relative to wild-type UGT1A8. However, mutations of UGT1A8 431CT and 830GA loci resulted in decreased activity of UDP glucuronosyltransferase enzymes and decreased production of the metabolite, respectively showing 62.9% (P P T had little effect on enzyme activity, with 96.8% activity relative to wild-type UGT1A8 (P = .0569). Conclusions: Our results showed that UGT1A8 gene polymorphisms can affect the activity of UDP glucuronosyltransferase enzyme, which may influence the elimination of mycophenolate mofetil in different patients.