title: 1,3-Butadiene-induced mitochondrial dysfunction is correlated with mitochondrial CYP2E1 activity in Collaborative Cross mice.
abstract: Cytochrome P450 2E1 (CYP2E1) metabolizes low molecular weight hydrophobic compounds, including 1,3-butadiene, which is converted by CYP2E1 to electrophilic epoxide metabolites that covalently modify cellular proteins and DNA. Previous CYP2E1 studies have mainly focused on the enzyme localized in the endoplasmic reticulum (erCYP2E1); however, active CYP2E1 has also been found in mitochondria (mtCYP2E1) and the distribution of CYP2E1 between organelles can influence an individual's response to exposure. Relatively few studies have focused on the contribution of mtCYP2E1 to activation of chemical toxicants. We hypothesized that CYP2E1 bioactivation of 1,3-butadiene within mitochondria adversely affects mitochondrial respiratory complexes I-IV. A population of Collaborative Cross mice was exposed to air (control) or 200ppm 1,3-butadiene. Subcellular fractions (mitochondria, DNA, and microsomes) were collected from frozen livers and CYP2E1 activity was measured in microsomes and mitochondria. Individual activities of mitochondrial respiratory complexes I-IV were measured using in vitro assays and purified mitochondrial fractions. In air- and 1,3-butadiene-exposed mouse samples, mtDNA copy numbers were assessed by RT-PCR, and mtDNA integrity was assessed through a PCR-based assay. No significant changes in mtDNA copy number or integrity were observed; however, there was a decrease in overall activity of mitochondrial respiratory complexes I, II, and IV after 1,3-butadiene exposure. Additionally, higher mtCYP2E1 (but not erCYP2E1) activity was correlated with decreased mitochondrial respiratory complex activity (in complexes I-IV) in the 1,3-butadiene-exposed (not control) animals. Together, these results represent the first in vivo link between mitochondrial CYP2E1 activity and mitochondrial toxicity.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States.
authors.forename: Jessica H
authors.initials: JH
authors.lastname: Hartman
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States. Electronic address: MillerGroverP@uams.edu.
authors.forename: Grover P
authors.initials: GP
authors.lastname: Miller
authors.affiliation: Department of Chemistry, Hendrix College, Conway, AR, United States.
authors.forename: Andres A
authors.initials: AA
authors.lastname: Caro
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States.
authors.forename: Stephanie D
authors.initials: SD
authors.lastname: Byrum
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States.
authors.forename: Lisa M
authors.initials: LM
authors.lastname: Orr
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States.
authors.forename: Samuel G
authors.initials: SG
authors.lastname: Mackintosh
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Arkansas for Medical Sciences, Little Rock, AR, United States.
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Tackett
authors.affiliation: Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR, United States.
authors.forename: Lee Ann
authors.initials: LA
authors.lastname: MacMillan-Crow
authors.affiliation: Department of Preventive Medicine and Community Health, University of Texas Medical Branch, Galveston, TX, United States; Sealy Center for Environmental Health and Medicine, University of Texas Medical Branch, Galveston, TX, United States.
authors.forename: Lance M
authors.initials: LM
authors.lastname: Hallberg
authors.affiliation: Sealy Center for Environmental Health and Medicine, University of Texas Medical Branch, Galveston, TX, United States; Division of Pulmonary, Critical Care, and Sleep Medicine, and Department of Pharmacology and Toxicology, United States.
authors.forename: Bill T
authors.initials: BT
authors.lastname: Ameredes
authors.affiliation: Department of Environmental and Occupational Health, University of Arkansas for Medical Sciences, Little Rock, AR, United States; The Winthrop P. Rockefeller Cancer Institute, University of Arkansas for Medical Sciences, Little Rock, AR, United States. Electronic address: gboysen@uams.edu.
authors.forename: Gunnar
authors.initials: G
authors.lastname: Boysen
mesh_terms: D000818:Animals; D002070:Butadienes / Q000633:toxicity*; D002273:Carcinogens / Q000633:toxicity*; D019392:Cytochrome P-450 CYP2E1 / Q000378:metabolism*; D056915:DNA Copy Number Variations; D004272:DNA, Mitochondrial / Q000378:metabolism; D042967:Electron Transport Complex I / Q000378:metabolism; D014450:Electron Transport Complex III / Q000378:metabolism; D003576:Electron Transport Complex IV / Q000378:metabolism; D005260:Female; D051379:Mice; D008930:Mitochondria, Liver / Q000187:drug effects* / Q000378:metabolism; D013385:Succinate Dehydrogenase / Q000378:metabolism
chemical_list: D002070:Butadienes; D002273:Carcinogens; D004272:DNA, Mitochondrial; D019392:Cytochrome P-450 CYP2E1; C000617651:cytochrome P-450 2E1, mouse; D013385:Succinate Dehydrogenase; D003576:Electron Transport Complex IV; D042967:Electron Transport Complex I; D014450:Electron Transport Complex III; C031763:1,3-butadiene
keywords: 1,3-Butadiene; CYP2E1; Collaborative Cross; Mitchondrial function