title: Hepatotoxicity of piperazine designer drugs: up-regulation of key enzymes of cholesterol and lipid biosynthesis.
abstract: The piperazine derivatives most frequently consumed for recreational purposes are 1-benzylpiperazine, 1-(3,4-methylenedioxybenzyl) piperazine, 1-(3-trifluoromethylphenyl) piperazine and 1-(4-methoxyphenyl) piperazine. Generally, they are consumed as capsules, tablets or pills but also in powder or liquid forms. Currently, the precise mechanism by which piperazine designer drugs induce hepatotoxicity and whether they act by a common pathway is unclear. To answer this question, we performed a gene array study with rat hepatocytes incubated with the four designer drugs. Non-cytotoxic concentrations were chosen that neither induce a decrease in reduced glutathione or ATP depletion. Analysis of the gene array data showed a large overlap of gene expression alterations induced by the four drugs. This 'piperazine designer drug consensus signature' included 101 up-regulated and 309 down-regulated probe sets (p < 0.05; FDR adjusted). In the up-regulated genes, GO groups of cholesterol biosynthesis represented a dominant overrepresented motif. Key enzymes of cholesterol biosynthesis up-regulated by all four piperazine drugs include sterol C4-methyloxidase, isopentyl-diphosphate-Δ-isomerase, Cyp51A1, squalene epoxidase and farnesyl diphosphate synthase. Additionally, glycoprotein transmembrane nmb, which participates in cell adhesion processes, and fatty acid desaturase 1, an enzyme that regulates unsaturation of fatty acids, were also up-regulated by the four piperazine designer drugs. Regarding the down-regulated probe sets, only one gene was common to all four piperazine derivatives, the betaine-homocysteine-S-methyltransferase 2. Analysis of transcription factor binding sites of the 'piperazine designer drug consensus signature' identified the sterol regulatory element binding protein (SREBP-1) as strongly overrepresented in the up-regulated genes. SREBP transcription factors are known to regulate multiple genes of cholesterol metabolism. In conclusion, the present study shows that piperazine designer drugs act by up-regulating key enzymes of cholesterol biosynthesis which is likely to increase the risk of phospholipidosis and steatosis.
authors.affiliation: UCIBIO/REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, 4050-313, Porto, Portugal. m.arbo@terra.com.br.
authors.forename: Marcelo Dutra
authors.initials: MD
authors.lastname: Arbo
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors (IFADO), Technical University of Dortmund, 44139, Dortmund, Germany.
authors.forename: Simone
authors.initials: S
authors.lastname: Melega
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors (IFADO), Technical University of Dortmund, 44139, Dortmund, Germany.
authors.forename: Regina
authors.initials: R
authors.lastname: Stöber
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors (IFADO), Technical University of Dortmund, 44139, Dortmund, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Schug
authors.affiliation: Department of Statistics, Technical University of Dortmund, 44221, Dortmund, Germany.
authors.forename: Eugen
authors.initials: E
authors.lastname: Rempel
authors.affiliation: Department of Statistics, Technical University of Dortmund, 44221, Dortmund, Germany.
authors.forename: Jörg
authors.initials: J
authors.lastname: Rahnenführer
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors (IFADO), Technical University of Dortmund, 44139, Dortmund, Germany.
authors.forename: Patricio
authors.initials: P
authors.lastname: Godoy
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors (IFADO), Technical University of Dortmund, 44139, Dortmund, Germany.
authors.forename: Raymond
authors.initials: R
authors.lastname: Reif
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors (IFADO), Technical University of Dortmund, 44139, Dortmund, Germany.
authors.forename: Cristina
authors.initials: C
authors.lastname: Cadenas
authors.affiliation: UCIBIO/REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, 4050-313, Porto, Portugal.
authors.forename: Maria
authors.initials: M
authors.lastname: de Lourdes Bastos
authors.affiliation: UCIBIO/REQUIMTE, Laboratório de Toxicologia, Departamento de Ciências Biológicas, Faculdade de Farmácia, Universidade do Porto, 4050-313, Porto, Portugal.
authors.forename: Helena
authors.initials: H
authors.lastname: Carmo
authors.affiliation: Leibniz Research Centre for Working Environment and Human Factors (IFADO), Technical University of Dortmund, 44139, Dortmund, Germany.
authors.forename: Jan G
authors.initials: JG
authors.lastname: Hengstler
mesh_terms: D000818:Animals; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D056486:Chemical and Drug Induced Liver Injury / Q000201:enzymology* / Q000378:metabolism / Q000473:pathology; D002784:Cholesterol / Q000819:agonists* / Q000096:biosynthesis; D015198:Designer Drugs / Q000633:toxicity*; D004790:Enzyme Induction / Q000187:drug effects*; D020869:Gene Expression Profiling; D022781:Hepatocytes / Q000187:drug effects* / Q000378:metabolism / Q000473:pathology; D020128:Inhibitory Concentration 50; D050356:Lipid Metabolism / Q000187:drug effects*; D008297:Male; D020411:Oligonucleotide Array Sequence Analysis; D009994:Osmolar Concentration; D010879:Piperazines / Q000633:toxicity*; D025341:Principal Component Analysis; D017208:Rats, Wistar
chemical_list: C000614532:1-(3,4-methylenedioxybenzyl)piperazine; D015198:Designer Drugs; D010879:Piperazines; C018406:1-(3-trifluoromethylphenyl)piperazine; C006737:1-benzylpiperazine; D002784:Cholesterol; C490166:1-(4-methoxyphenyl)piperazine
keywords: Cholesterol metabolism; Gene arrays; Hepatotoxity; Piperazine designer drugs