Allan Rettie

Professor

Department of Medicinal Chemistry, Medicinal Chemistry Faculty, Pharmacogenomics Research Network, Rettie Lab

Expertise: Cytochrome P450, Dietary Supplements and Vitamins, Drug Interactions, Drug Metabolism, Distribution and Transport, Pharmacogenomics and Personalized Medicine, Toxicology

Telephone: (206) 685-0615

Email: rettie@uw.edu

Website: PubMed Link

Education

  • PhD in Pharmaceutical Sciences, University of Newcastle-upon-Tyne, England
  • BSc, Heriot-Watt University, Scotland
  • Postdoctoral Fellow, UW

Research Areas

  • Biochemistry of the human CYP2 and CYP4 families of P450s
  • Pharmacogenomics of cardiovascular drugs
  • P450-dependent bioactivation and associated adverse reactions

Biography

Dr. Rettie obtained a PhD in Pharmaceutical Sciences in 1983 from the University of Newcastle-upon-Tyne, England, before moving to Seattle to post-doc with Drs. Mont Juchau and Dr. Bill Trager at the UW in the areas of extra-hepatic drug metabolism and mechanisms of drug-drug interactions. He joined the faculty of the UW School of Pharmacy in 1987 and was Department Chair from 2000-2014.

Dr. Rettie’s research interests have focused mainly on the human P450 enzymes and attempts to understand mechanisms of catalysis, substrate specificity, pharmacogenetic variability and adverse drug reactions related to these monooxygenases. He has published over 170 peer-reviewed papers and held research grants from the National Institutes of Health (NIH) in these topic areas for the last 25 years.

Dr. Rettie has served on the editorial boards of Drug Metabolism and Disposition, Drug Metabolism Reviews, Journal of Pharmacology and Therapeutics, Current Drug Metabolism, Chemico-Biological Interactions and Chemical Research in Toxicology, as well as numerous NIH grant review panels. He currently chairs the Scientific Affairs Committee of the International Society for Study of Xenobiotics (ISSX) and is Past Chair of the International Union of Basic and Applied Pharmacology’s Section of Drug Metabolism and Transport. In 2005, Dr. Rettie received the North American Scientific Achievement Award from ISSX for his work on elucidating metabolic and pharmacogenetic mechanisms of adverse reactions to the anticoagulant drug, warfarin. He holds several patents relating to the clinical utility of warfarin response gene pharmacogenomics.

Research Overview

Metabolism by the cytochrome P450s is the principal means whereby lipid-soluble drugs and compounds foreign to the body are converted to water-soluble derivatives that can be readily excreted. This is a beneficial effect of the enzyme system. However, it is well recognized that P450-mediated bioactivation of drugs and other xenobiotics is an important mechanism of chemical toxicity (Baillie and Rettie, 2011). Moreover, unexpected interruptions in P450 activity, due to genetic variation (Danese et al., 2012) or administration of agents that inhibit P450 activity (McDonald et al., 2015), can cause serious adverse drug reactions and contribute to disease states.

Much of the current research in the Rettie laboratory focuses on the biochemistry and pharmacogenetics of the vitamin K cycle with an emphasis on how P450 enzymes interact with components of the cycle to maintain homeostasis. Human CYP2C9, for example, is the primary catalyst of (S)-warfarin metabolism. This vitamin K antagonist is an anticoagulant drug that is very difficult to dose correctly, and there are many drug-drug and drug-gene interactions associated with its use (Rettie and Tai, 2006).

An important goal for the laboratory is to define sources of inter-individual variability in warfarin dosing which can span a 100-fold range (Cooper et al., 2008). We have shown that common genetic polymorphisms in CYP2C9 decrease warfarin dose requirements by reducing the metabolic clearance of (S)-warfarin, while common polymorphisms in the warfarin target enzyme, VKORC1, affect warfarin dose by changing hepatic concentrations of this critical recycling enzyme (Rieder et al., 2005). We found recently that CYP4F2 and CYP4F11 are key vitamin K catabolizing enzymes (Edson et al., 2013) and common variation in CYP4F2 at least, affects warfarin dose, likely by modulating hepatic vitamin K concentrations (McDonald et al., 2009). We are currently evaluating this hypothesis as well as elucidating novel catabolic pathways of vitamin K2.

Other research in the laboratory is concerned with CYP4 enzymes that are potential drug targets because of their critical roles in health and disease (Edson et al., 2013; Johnson et al., 2015), and efforts are ongoing to synthesize chemical inhibitors of specific CYP4-family members to better dissect their physiological roles. CYP4B1 metabolizes a host of pro-toxins, including furans, aromatic amines, and certain fatty acids to reactive intermediates that can damage the cell. In this regard, CYP4B1 is a curious member of the CYP4 family because these enzymes typically have a restricted substrate specificity that does not extend much beyond endogenous fatty acids, such as arachidonate. Most recently, we identified structural determinants of CYP4B1 that confer high activity towards 4-ipomeanol (Wiek et al., 2015).

To evaluate the role of CYP4B1 in chemical toxicity, we have also developed a knockout mouse model (Parkinson et al, 2013). Finally, we are studying CYP4V2 – a novel ‘orphan P450’ whose substrate specificity is unknown. To date we have reported on the fatty acid substrate specificity of CYP4V2 (Nakano et al., 2009) and the enzyme’s distribution in the eye (Nakano et al., 2012). Intriguingly, polymorphisms in CYP4V2 are found in patients suffering from the eye disease Bietti’s Crystalline Dystrophy (BCD). We are attempting to ‘de-orphanize’ CYP4V2 and, in the process, discover which homeostatic mechanisms have been disrupted in BCD patients (Kelly et al., 2011). A knockout mouse model for CYP4V2 that recapitulates BCD has recently been developed in collaboration with the Kelly laboratory that should facilitate these efforts (Lockhart et al., 2014).

In general, we use genetic re-engineering coupled with conventional protein biochemistry methods for the expression and isolation of CYP2 and CYP4 proteins and mutants of interest from heterologous hosts such as E.coli and insect cells (Mosher et al., 2008; Roberts et al., 2010). We also make extensive use of mass spectrometry for analyte quantification, including evaluation of structural changes in mutant proteins and lipidomic analysis to probe changes in endogenous metabolism due to CYP4V and CYP2C enzyme polymorphisms. Gene sequencing to discover novel polymorphisms in important pharmacogenes and disease-associated P450s is a continuing focus of the laboratory. Synthetic chemistry comes into play in the preparation of new substrates, inhibitors and metabolites for P450s of interest. Our long-term goals are to understand how structure and function are related for these important P450 enzyme families, and how their dysregulation affects drug response and disease.

Selected Publications

  • Roellecke K, Virts EL, Einholz R, Edson KZ, Altvater B, Rossig C, von Laer D, Scheckenbach K, Wagenmann M, Reinhardt D, Kramm CM, Rettie AE, Wiek C, Hanenberg H. “Optimized human CYP4B1 in combination with the alkylator prodrug 4-ipomeanol serves as a novel suicide gene system for adoptive T-cell therapies.” Gene Ther. 2016 April 19[Epub ahead of print].PubMed link.
  • McDonald MG, Au NT, Rettie AE.“P450-Based Drug-Drug Interactions of Amiodarone and its Metabolites: Diversity of Inhibitory Mechanisms.” Drug Metab. Disposition.2015 Aug 21; 43(11):1661-9.PubMed link.
  • Johnson AL, Eson KZ, Totah RA, Rettie AE. “Cytochrome P450 ω-Hydroxylases in Inflammation and Cancer.” Adv. Pharmacol.2015 Jun 27;74:223-262. PubMed link.
  • Fohner AE, Robinson R, Yracheta J, Rettie AE, et al. “Variation in genes controlling warfarin disposition and response in American Indian and Alaska Native people: CYP2C9, VKORC1, CYP4F2, CYP4F11, GGCX.” Pharmacogenet Genomics 2015 May 4 [Epub ahead of print]. PubMed link.
  • Caudle KE, Rettie AE, Whirl-Carrillo M, et al. “Clinical pharmacogenetics implementation consortium guidelines for CYP2C9 and HLA-B genotypes and phenytoin dosing.” Clin Pharmacol Ther. 2014 Nov; 96(5):542-8. PubMed link.
  • Lockhard CM, Nakano M, Rettie AE, Kelly EJ. “Generation and characterization of a murine model of Bietti crystalline dystrophy.” Invest Opthalmol Vis Sci. 2014 Aug 12; 55(9):5572-81. PubMed link.
  • Nakano M, Lockhart CM, Kelly EJ, Rettie AE. “Ocular cytochrome P450s and transporters: roles in disease and endobiotic and xenobiotic disposition.” Drug Metab Rev. 2014 Aug; 46(3):247-60. PubMed link.
  • Haque JA, McDonald MG, Kulman JD, Rettie AE. “A cellular system for quantitation of vitamin K cycle activity: structure-activity effects on vitamin K antagonism by warfarin metabolites.” Blood 2014 Jan 23; 123(4):582-9. PubMed link.
  • Edson KZ, Rettie AE. “CYP4 Enzymes as Potential Drug Targets: Focus on Enzyme Multiplicity, Inducers and Inhibitors, and Therapeutic Modulation of 20-Hydroxyeicosatetraenoic Acid (20-HETE) Synthase and Fatty Acid ω-Hydroxylase Activities.” Curr Top Med Chem. 2013; 13(12):1429-40. PubMed link.
  • Parkinson OT, Liggett HD, Rettie AE, Kelly ED. “Generation and Characterization of a CYP4B1 Null Mouse and the Role of CYP4B1 in the Activation and Toxicity of Ipomeanol.” Toxicol Sci. Aug; 134:243-50. PubMed link.
  • Danese E, Montagnana M, Johnson JA, Rettie AE, Zambon CF, et al. “Impact of the CYP4F2 p.V433M polymorphism on coumarin dose requirement: systematic review and meta-analysis.” Clin Pharmacol Ther. 2012 Dec; 92(6):746-56. PubMed link.
  • Nakano M, Kelly EJ, Wiek C, Hanenberg H, Rettie AE. “CYP4V2: Ocular Localization, Oxidation of w-3 Polyunsaturated Fatty Acids and Functional Deficit of the H331P Variant in Relation to Bietti’s Crystalline Dystrophy.” Mol Pharmacol. 2012; 82:679-86.