title: Induction of metallothionein isoforms by copper diethyldithiocarbamate in cultured vascular endothelial cells.
abstract: Metallothionein (MT) plays a central role in cellular defense against heavy metals and oxidative stress. Since the induction of MT requires the activation of metal response element (MRE)-binding transcription factor-1 (MTF-1) by binding of zinc ions, inorganic zinc is regarded as a typical MT inducer. However, in a previous report, we showed that inorganic zinc could not induce MT in vascular endothelial cells. While it is suggested that endothelial MT presents mechanisms different from those of other cell types, these remain unclear. In this study, we investigated whether the induction of endothelial MT expression involves the Nrf2-ARE pathway using copper(II) bis(diethyldithiocarbamate), termed Cu10, using a culture system of bovine aortic endothelial cells. Cu10 induced MT-1/2 protein expression and increased the expression of mRNAs for MT-1A, MT-1E, and MT-2, MT isoforms expressed in the cells. Cu10 activated not only the MTF-1-MRE, but also the Nrf2-ARE pathway. MTF-1 knockdown resulted in the repression of Cu10-induced MT-1 and -2 expression. Cu10-induced MT-1 expression was down-regulated by Nrf2 knockdown. However, MT-2 expression was not affected by Nrf2 knockdown. These results suggest that the expression of endothelial MT is up-regulated by the Nrf2-ARE pathway as well as by the MTF-1-MRE pathway. Moreover, MT-1 regulation mechanisms differ from that of MT-2. Specifically, the present data support the hypothesis that MT-1 participates in the biological defense system, while MT-2 mainly regulates intracellular zinc metabolism.
authors.affiliation: Department of Environmental Health, Faculty of Pharmaceutical Sciences, Tokyo University of Science.
authors.forename: Tomoya
authors.initials: T
authors.lastname: Fujie
authors.forename: Yukino
authors.initials: Y
authors.lastname: Segawa
authors.forename: Eiko
authors.initials: E
authors.lastname: Yoshida
authors.forename: Tomoki
authors.initials: T
authors.lastname: Kimura
authors.forename: Yasuyuki
authors.initials: Y
authors.lastname: Fujiwara
authors.forename: Chika
authors.initials: C
authors.lastname: Yamamoto
authors.forename: Masahiko
authors.initials: M
authors.lastname: Satoh
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Naka
authors.forename: Toshiyuki
authors.initials: T
authors.lastname: Kaji
mesh_terms: D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D003300:Copper / Q000494:pharmacology*; D004268:DNA-Binding Proteins / Q000235:genetics / Q000378:metabolism; D004050:Ditiocarb / Q000494:pharmacology*; D042783:Endothelial Cells / Q000378:metabolism*; D015870:Gene Expression; D055785:Gene Knockdown Techniques; D008668:Metallothionein / Q000378:metabolism* / Q000502:physiology; D019216:Metals, Heavy / Q000633:toxicity; D051267:NF-E2-Related Factor 2 / Q000235:genetics / Q000378:metabolism; D018384:Oxidative Stress; D020033:Protein Isoforms / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects / Q000235:genetics; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D015854:Up-Regulation; D000097809:Transcription Factor MTF-1
chemical_list: D003300:Copper; D004268:DNA-Binding Proteins; D004050:Ditiocarb; D008668:Metallothionein; D019216:Metals, Heavy; D051267:NF-E2-Related Factor 2; D020033:Protein Isoforms; D014157:Transcription Factors; D000097809:Transcription Factor MTF-1; C495635:NFE2L2 protein, human