Cytochrome P450 Research

Cytochrome P450 Enzymes; CYPs

My basic research program focuses on the cytochrome P450 superfamily of proteins with an emphasis on their evolution and function in aquatic species such as fish.  Cytochrome P450 enzymes, or CYPs, are heme proteins critical for generation of major biological signaling molecules (e.g. steroid hormones) and for the detoxification of xenobiotics (e.g. drugs, environmental contaminants).  CYPs are a key component of the defensome – the genes that aid in protection and defense from toxic compounds.  Vertebrate species have 50-100 CYP genes in their genome but the function of many of these genes in non-mammalian species is unclear.  We have a primary interest in understanding the evolution and function of CYPs in aquatic organisms.

CYP4 phylogeny

Our projects involve genome annotation of CYP sequences, phylogenetic studies of CYP families, protein expression and functional testing of CYPs.  This research raises fundamental questions about CYP protein function and attracts students with strong interests in protein evolution, bioinformatics, molecular biology and biochemistry.

Bioinformatics approaches are used in genome annotations of CYP genes and phylogenetic studies that raise functional hypotheses regarding novel CYP sequences.  With each new genome completed, an array of CYP sequences are identified for which functional knowledge is lacking.  Our basic science research is directly aimed at uncovering the function of these novel genes and understanding the capacity of CYP systems in aquatic species.

Spectrum of expressed zebrafish CYP

Much of the tools used to examine CYP function were designed for mammalian systems.  My lab has undertaken experiments meant to directly compare and contrast the function of CYP systems in mammalian and piscine liver; the major organ for xenobiotic metabolism.  We have tested the capacity of fish hepatic CYP mediated metabolism using fluorogenic substrates and examined CYP enzyme inhibition with typical mammalian CYP inhibitors.  Since the liver expresses multiple CYP isoforms, we have expressed several CYP enzymes including those in the CYP1 and CYP3 family to investigate the function of specific CYPs important for drug, xenobiotic, and estradiol metabolism.

NAPH and NADP+ detected by CE

Our ability to study CYP systems is limited by the available tools.  In collaboration with the lab of Dr. Philip Britz-McKibbin (Department of Chemistry, McMaster University), we have developed a capillary electrophoresis assay for CYP function.  CYPs require the donation of electrons from NADPH to complete their catalytic cycle, typically hydroxylation reactions.  While most assays monitor the loss of substrate or generation of metabolite, these assays are very specific for single compounds.  The measurement of NADPH consumption would provide a generic assay for CYP activity that would allow for screening of CYP function with low cost and higher throughput.  Our current research is aimed at using high throughput screening approaches to build structure-activity relationships and uncover function of our expressed CYP proteins.  This research is completed in McMaster’s High Throughput Screening Laboratory using libraries of chemicals derived from natural products and off-label drugs.

This research has been funded by the Natural Sciences and Engineering Research Council of Canada (NSERC) Discovery and Accelerator Programs, the Canadian Foundation of Innovation (CFI), and Ontario Innovation Trust (OIT).

Recent Posts

Bring on the summer!

With each academic term change, there can be a change in who is doing research in the Wilson Tox Lab.  But summer and fall term mark times of large change, as undergraduates  and graduate students complete their thesis research, write up, and move on to new challenges.  This year it is a bit of an exception as many of the undergraduates that have been working in our lab over the last year are staying to continue their research.  Kirill Pankov, an undergraduate student that works between Dr. Andrew McArthur’s lab and Wilson Tox Lab, had a very successful thesis.  He won the best thesis presentation for the Biomedical Discovery and Commercialization Program (BDC); no mean feat considering he was discussing his research in Cnidarian genomes!  Kirill is continuing to work on that project over the summer with the hopes that we are wrapping up a project spanning multiple Cnidarian genomes and will be able to move into nomenclature of the cytochrome P450 genes in this important animal phylum.  Caitlin West and Devon Jones completed their undergraduate theses in the Biology, Physiology Specialization Program and are remaining in the lab to contribute to our whitefish program (Caitlin) and mouse fetal programming project (Devon).  Devon won best poster presentation for the Biology Department’s senior thesis class.  Caitlin has just won the best video in the iClimate video competition, showcasing excellent science communication skills.  Check out her video on the iClimate Facebook page; a link is provided on our research pages.  These are just three of the seven undergraduates working in the lab this summer.

We do have a few new people that have joined the lab in 2017.  Meghan Fuzzen joined us in January to begin a post doctoral fellowship after completing her PhD at Waterloo.  She was actually out in the field with us in late fall for whitefish spawning, working ahead of her PDF to get experiments going.  Hard core scientist in our midst and we are so glad to have her!  Allison Kennedy is another post doctoral fellow that has joined the group more recently.  Allison has been working at NOSM with our collaborator, Dr. Doug Boreham, and has moved to McMaster to work on our Mouse Fetal Programming project as part of our ongoing collaboration with the Boreham lab.  We also have two new PhD students in our midst this summer.  Andrea Murillo has moved from the University of Regina and Dr. Richard Manzon’s lab to complete her PhD with us.  We have gotten to know Andrea over the last two years of her MSc degree, where she worked on heat shock proteins in developing whitefish.  We were lucky enough to have her in the field with us each fall for the last few years, collecting spawning whitefish to perform IVF and generate embryos for our research program.  Andrea’s research is going to move us into more invertebrate species and allow us to continue our research on cytochrome P450 enzymes in the marine annelid worm, Capitella telata.  James McEvoy will be joining us shortly from Australia, where he is completing a PhD at Flinders University.  He is our first Cotutelle student and will get his degree from both Flinders and McMaster!

And of course, we are starting to look forward to fall and the next major change in the lab.  Three graduate students are wrapping up their research; both Adam and Shayen will be finishing their MSc degrees by fall term and Shamaila is finishing the last bit of her PhD research this summer.  So between research and writing manuscripts, this is shaping up to be one exciting summer in the Wilson Tox Lab.

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