title: Nicotine induces mitochondrial fission through mitofusin degradation in human multipotent embryonic carcinoma cells.
abstract: Nicotine is considered to contribute to the health risks associated with cigarette smoking. Nicotine exerts its cellular functions by acting on nicotinic acetylcholine receptors (nAChRs), and adversely affects normal embryonic development. However, nicotine toxicity has not been elucidated in human embryonic stage. In the present study, we examined the cytotoxic effects of nicotine in human multipotent embryonal carcinoma cell line NT2/D1. We found that exposure to 10 μM nicotine decreased intracellular ATP levels and inhibited proliferation of NT2/D1 cells. Because nicotine suppressed energy production, which is a critical mitochondrial function, we further assessed the effects of nicotine on mitochondrial dynamics. Staining with MitoTracker revealed that 10 μM nicotine induced mitochondrial fragmentation. The levels of the mitochondrial fusion proteins, mitofusins 1 and 2, were also reduced in cells exposed to nicotine. These nicotine effects were blocked by treatment with mecamylamine, a nonselective nAChR antagonist. These data suggest that nicotine degrades mitofusin in NT2/D1 cells and thus induces mitochondrial dysfunction and cell growth inhibition in a nAChR-dependent manner. Thus, mitochondrial function in embryonic cells could be used to assess the developmental toxicity of chemicals.
authors.affiliation: Division of Pharmacology, National Institute of Health Sciences, Japan.
authors.forename: Naoya
authors.initials: N
authors.lastname: Hirata
authors.affiliation: Division of Pharmacology, National Institute of Health Sciences, Japan.
authors.forename: Shigeru
authors.initials: S
authors.lastname: Yamada
authors.affiliation: Division of Pharmacology, National Institute of Health Sciences, Japan; Faculty of Engineering, Department of Materials Science and Engineering, Yokohama National University, Japan.
authors.forename: Miki
authors.initials: M
authors.lastname: Asanagi
authors.affiliation: Division of Pharmacology, National Institute of Health Sciences, Japan.
authors.forename: Yuko
authors.initials: Y
authors.lastname: Sekino
authors.affiliation: Division of Pharmacology, National Institute of Health Sciences, Japan. Electronic address: kanda@nihs.go.jp.
authors.forename: Yasunari
authors.initials: Y
authors.lastname: Kanda
mesh_terms: D045744:Cell Line, Tumor; D004305:Dose-Response Relationship, Drug; D054278:Embryonal Carcinoma Stem Cells / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D020558:GTP Phosphohydrolases / Q000378:metabolism*; D000066449:Human Embryonic Stem Cells / Q000187:drug effects / Q000378:metabolism / Q000473:pathology; D006801:Humans; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism* / Q000473:pathology; D063154:Mitochondrial Dynamics / Q000187:drug effects*; D033681:Mitochondrial Membrane Transport Proteins / Q000378:metabolism*; D024101:Mitochondrial Proteins / Q000378:metabolism*; D009538:Nicotine / Q000008:administration & dosage*
chemical_list: D033681:Mitochondrial Membrane Transport Proteins; D024101:Mitochondrial Proteins; D009538:Nicotine; D020558:GTP Phosphohydrolases; C470018:MFN2 protein, human; C470017:Mfn1 protein, human
keywords: Cigarette smoking; Embryonic cells; Mitochondrial fission; Mitofusin; Nicotine