title: Sibutramine provokes apoptosis of aortic endothelial cells through altered production of reactive oxygen and nitrogen species.
abstract: Overdose administration of sibutramine, a serotonin-noradrenalin reuptake inhibitor, is considered to elicit severe side effects including hypertension, whose pathogenic mechanism remains unclear. Here, we found that 48-h incubation with >10μM sibutramine provokes apoptosis of human aortic endothelial (HAE) cells. Treatment with the lethal concentration of sibutramine facilitated production of reactive oxygen species (ROS), altered expression of endoplasmic reticulum stress response genes (heat shock protein 70 and C/EBP homologous protein), and inactivated 26S proteasome-based proteolysis. The treatment also decreased cellular level of nitric oxide (NO) through lowering of expression and activity of endothelial NO synthase. These results suggest that ROS production and depletion of NO are crucial events in the apoptotic mechanism and may be linked to the pathogenesis of vasoconstriction elicited by the drug. Compared to sibutramine, its metabolites (N-desmethylsibutramine and N-didesmethylsibutramine) were much less cytotoxic to HAE cells, which hardly metabolized sibutramine. In contrast, both the drug and metabolites showed low cytotoxicity to hepatic HepG2 cells with high metabolic potency and expression of cytochrome P450 (CYP) 3A4. The cytotoxicity of sibutramine to HepG2 and Chang Liver cells was remarkably augmented by inhibition and knockdown of CYP3A4. This study also suggests an inverse relationship between sibutramine cytotoxicity and CYP3A4-mediated metabolism into the N-desmethyl metabolites.
authors.affiliation: Forensic Science Laboratory, Gifu Prefectural Police Headquarters, Gifu 500-8501, Japan.
authors.forename: Yoshifumi
authors.initials: Y
authors.lastname: Morikawa
authors.affiliation: Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu 501-1196, Japan.
authors.forename: Akinobu
authors.initials: A
authors.lastname: Shibata
authors.affiliation: Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu 501-1196, Japan.
authors.forename: Naoko
authors.initials: N
authors.lastname: Okumura
authors.affiliation: Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu 501-1196, Japan.
authors.forename: Akira
authors.initials: A
authors.lastname: Ikari
authors.affiliation: Forensic Science Laboratory, Gifu Prefectural Police Headquarters, Gifu 500-8501, Japan.
authors.forename: Yasuhide
authors.initials: Y
authors.lastname: Sasajima
authors.affiliation: Forensic Science Laboratory, Gifu Prefectural Police Headquarters, Gifu 500-8501, Japan.
authors.forename: Koichi
authors.initials: K
authors.lastname: Suenami
authors.affiliation: Forensic Science Laboratory, Gifu Prefectural Police Headquarters, Gifu 500-8501, Japan.
authors.forename: Kiyohito
authors.initials: K
authors.lastname: Sato
authors.affiliation: Forensic Science Laboratory, Gifu Prefectural Police Headquarters, Gifu 500-8501, Japan.
authors.forename: Yuji
authors.initials: Y
authors.lastname: Takekoshi
authors.affiliation: Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan.
authors.forename: Ossama
authors.initials: O
authors.lastname: El-Kabbani
authors.affiliation: Laboratory of Biochemistry, Gifu Pharmaceutical University, Gifu 501-1196, Japan. Electronic address: matsunagat@gifu-pu.ac.jp.
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Matsunaga
mesh_terms: D000928:Antidepressive Agents / Q000494:pharmacology*; D001011:Aorta / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D017209:Apoptosis / Q000187:drug effects*; D002478:Cells, Cultured; D003503:Cyclobutanes / Q000494:pharmacology*; D059865:Endoplasmic Reticulum Stress; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D006801:Humans; D018384:Oxidative Stress; D026361:Reactive Nitrogen Species / Q000378:metabolism*; D017382:Reactive Oxygen Species / Q000378:metabolism*
chemical_list: D000928:Antidepressive Agents; D003503:Cyclobutanes; D026361:Reactive Nitrogen Species; D017382:Reactive Oxygen Species; C058254:sibutramine
keywords: Apoptosis; Endothelial cell; Nitric oxide; Reactive oxygen species; Sibutramine