MRE-binding transcription factor-1 is activated during endotoxemia: a central role for metallothionein

Kimura, Toshikiro; Itoh, Norio; Takehara, Miyako; Oguro, Ikuyo; Ishizaki, Junichi; Nakanishi, Takashi; Tanaka, Keiichi

doi:10.1016/s0378-4274(01)00473-8

Cited by 16 publications

(13 citation statements)

References 34 publications

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“…Firefly reporter plasmid pGL4.12-MRE d4 and pGL4.12-ARE 4 × 3 were cloned as previously described (Kimura et al, 2002(Kimura et al, , 2009) and used for the MRE or ARE-driven reporter assay. The reporter plasmids were transfected using Lipofectamine LTX reagent with PLUS reagent (Invitrogen) according to the manufacturer's instructions.…”

Section: Luciferase Assaymentioning

confidence: 99%

Induction of metallothionein isoforms by copper diethyldithiocarbamate in cultured vascular endothelial cells

et al. 2016

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-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.

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Section: Luciferase Assaymentioning

confidence: 99%

Induction of metallothionein isoforms by copper diethyldithiocarbamate in cultured vascular endothelial cells

et al. 2016

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“…In previous experiments using the luciferase reporter assay we observed activation of MTF-1. 20) By comparison, MTF-1 DNA-binding activity did not increase in MT-overexpressing cells (approximately 300-fold MT concentration, Fig. 2A and 2B).…”

Section: Resultsmentioning

confidence: 81%

“…Mouse hepatocytes were isolated by the in situ two step collagenase perfusion method as previously described. 20) The hepatocytes were plated in Williams' medium E containing 5% FBS, 1 µM dexamethasone (Dex) and 1 µM insulin. Preparation of Nuclear Extracts and Electrophoretic Mobility Shift Assays --Nuclear extracts were prepared by the method of Dalton et al 3) Binding reactions in the electrophoretic mobility shift assays (EMSA) were performed using binding buffer containing 12 mM 4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid (HEPES, pH 7.9), 5 mM MgCl 2 , 60 mM KCl, 0.5 mM dithiothreitol, 2 µg of poly(dI-dC), 2.5 pmol of mutant MRE oligonucleotide (mutMREs; 5 -GATCCAGGGAGCTAATTACTCCGCCCGAA-AAGTA-3 ), and 5-50 fmol of 32 P-labeled MRE oligonucleotide (MREs; 5 -GATCCAGGGAG-CTCTGCACACGGCCCGAAAAGTA-3 ), with 0.2-0.5 µl of recombinant human MTF-1 protein (1.0 pmol) in a total volume of 20 µl.…”

Section: Methodsmentioning

confidence: 99%

Metal Response Element-binding Transcription Factor-1 Is Activated by Degradation of Metallothionein

Kimura

Okumura

Oguro

et al. 2009

JOURNAL OF HEALTH SCIENCE

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Cytosolic zinc-binding protein, metallothionein (MT), is normally saturated with Zn. It is thought that Znsaturated MT (Zn-MT) acts as a major intracellular Zn pool. Metal-response element-binding transcription factor-1 (MTF-1) plays an important role in Zn-mediated MT transcription. Here, we showed that degradation of Zn-MT activates MTF-1. We measured activated MTF-1 using an electrophoretic mobility shift assay. Interleukin-6 induced MT expression and increased MTF-1 activity. MTF-1 activation was not observed in MT-overexpressing cells. MT-dependent MTF-1 activation was observed only after treating MT-overexpressing cells with cycloheximide (CHX), a protein synthesis inhibitor. CHX-treatment increased the degradation/synthesis ratio of protein. An increase in the degradation/synthesis ratio for the MT protein is expected to increase the level of labile Zn and activate MTF-1. Recombinant MTF-1 was activated by H 2 O 2 only in the presence of Zn-MT. Oxidative stress activated MTF-1 DNA-binding activity in primary cultured hepatocytes but not in MT-deficient hepatocytes. These findings suggest that degradation of Zn-MT activates MTF-1, and that MT plays an important role in zinc-mediated signal transduction.

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“…2). 62) The intracellular free zinc concentration is tightly regulated. Transcription mediated by Zur and ZntR, Zn-responsive TFs of Escherichia coli (E. coli), responded to around 10 -15 M free zinc.…”

Section: Function Of Mt In Modification Of Transcriptional Activitymentioning

confidence: 99%

Function of Metallothionein in Gene Expression and Signal Transduction: Newly Found Protective Role of Metallothionein

Kimura

Itoh

2008

JOURNAL OF HEALTH SCIENCE

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A heavy-metal-binding protein, metallothionein (MT), is induced by heavy metal overload and reactive oxygen species (ROS). The metals and ROS are rendered harmless by binding to MT or by oxidizing MT, respectively. This is a well-known role of MT. MT is also induced by glucocorticoids and cytokines. Induced MT may increase intracellular free zinc and modulate the activity of transcription factors. Changes in MT levels are thought to help in adaptation to changes in environmental conditions. MT modulates inflammatory reactions, including lipopolysaccharide (LPS)-induced expression of cytokines, nitric oxide production from macrophages in response to LPS, and resistance to LPS/D-galactosamine-induced lethality. In this review, we focus on a newly found protective role of MT, which acts mainly via changes in intracellular zinc levels or modulation of gene expression.

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MRE-binding transcription factor-1 is activated during endotoxemia: a central role for metallothionein

Cited by 16 publications

References 34 publications

Induction of metallothionein isoforms by copper diethyldithiocarbamate in cultured vascular endothelial cells

Induction of metallothionein isoforms by copper diethyldithiocarbamate in cultured vascular endothelial cells

Metal Response Element-binding Transcription Factor-1 Is Activated by Degradation of Metallothionein

Function of Metallothionein in Gene Expression and Signal Transduction: Newly Found Protective Role of Metallothionein

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