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The effect of alcohol and hydrogen peroxide on liver hepcidin gene expression in mice lacking antioxidant enzymes, glutathione peroxidase-1 or catalase.

Harrison-Findik DD, Lu S - Biomolecules (2015)

Bottom Line: Gpx-1(-/-) displayed significantly higher hepatic H2O2 levels than catalase(-/-) compared to wild-type mice, as measured by 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA).In conclusion, our findings strongly suggest that H2O2 inhibits hepcidin expression in vivo.Synergistic induction of CHOP by alcohol and H2O2, in the absence of gpx-1, stimulates liver hepcidin gene expression by ER stress independent of CREBH.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine, Division of Gastroenterology/Hepatology, University of Nebraska Medical Center, Omaha, NE 68198, USA. dharrisonfindik@unmc.edu.

ABSTRACT
This study investigates the regulation of hepcidin, the key iron-regulatory molecule, by alcohol and hydrogen peroxide (H2O2) in glutathione peroxidase-1 (gpx-1(-/-)) and catalase (catalase(-/-)) knockout mice. For alcohol studies, 10% ethanol was administered in the drinking water for 7 days. Gpx-1(-/-) displayed significantly higher hepatic H2O2 levels than catalase(-/-) compared to wild-type mice, as measured by 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA). The basal level of liver hepcidin expression was attenuated in gpx-1(-/-) mice. Alcohol increased H2O2 production in catalase(-/-) and wild-type, but not gpx-1(-/-), mice. Hepcidin expression was inhibited in alcohol-fed catalase(-/-) and wild-type mice. In contrast, alcohol elevated hepcidin expression in gpx-1(-/-) mice. Gpx-1(-/-) mice also displayed higher level of basal liver CHOP protein expression than catalase(-/-) mice. Alcohol induced CHOP and to a lesser extent GRP78/BiP expression, but not XBP1 splicing or binding of CREBH to hepcidin gene promoter, in gpx-1(-/-) mice. The up-regulation of hepatic ATF4 mRNA levels, which was observed in gpx-1(-/-) mice, was attenuated by alcohol. In conclusion, our findings strongly suggest that H2O2 inhibits hepcidin expression in vivo. Synergistic induction of CHOP by alcohol and H2O2, in the absence of gpx-1, stimulates liver hepcidin gene expression by ER stress independent of CREBH.

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Liver ATF4 and ATF6 mRNA expression. cDNA synthesized from liver RNA of wild-type and catalase−/− or gpx-1−/− transgenic mice, fed with plain water (H2O) or ethanol (alc.), was employed to determine ATF4 (A) and ATF6 (B) mRNA expression by real-time PCR. Gene expression levels in alcohol fed wild-type and untreated or alcohol-fed transgenic mice were expressed as-fold ATF expression of that in wild-type mice fed with water. Asterisks indicate statistical significance (p < 0.05).
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biomolecules-05-00793-f006: Liver ATF4 and ATF6 mRNA expression. cDNA synthesized from liver RNA of wild-type and catalase−/− or gpx-1−/− transgenic mice, fed with plain water (H2O) or ethanol (alc.), was employed to determine ATF4 (A) and ATF6 (B) mRNA expression by real-time PCR. Gene expression levels in alcohol fed wild-type and untreated or alcohol-fed transgenic mice were expressed as-fold ATF expression of that in wild-type mice fed with water. Asterisks indicate statistical significance (p < 0.05).

Mentions: The transcription factors, ATF4 and ATF6, which are activated by ER stress, have been shown to regulate CHOP expression [21]. The level of ATF4 and ATF6 mRNA expression in the livers of untreated and alcohol-treated transgenic and wild-type mice was determined by real-time PCR (Figure 6). The expression of ATF4 in the liver was significantly increased in gpx-1−/− and was unchanged in catalase−/− mice, compared to wild-type mice (Figure 6A). Alcohol however significantly inhibited ATF4 mRNA expression in gpx-1−/−, but not catalase−/− or wild-type, mice (Figure 6A). No significant changes in ATF6 mRNA expression were observed in transgenic mice compared to wild-type mice (Figure 6B). Similarly, ATF6 mRNA expression was not altered by alcohol treatment in wild-type or transgenic mice (Figure 6B).


The effect of alcohol and hydrogen peroxide on liver hepcidin gene expression in mice lacking antioxidant enzymes, glutathione peroxidase-1 or catalase.

Harrison-Findik DD, Lu S - Biomolecules (2015)

Liver ATF4 and ATF6 mRNA expression. cDNA synthesized from liver RNA of wild-type and catalase−/− or gpx-1−/− transgenic mice, fed with plain water (H2O) or ethanol (alc.), was employed to determine ATF4 (A) and ATF6 (B) mRNA expression by real-time PCR. Gene expression levels in alcohol fed wild-type and untreated or alcohol-fed transgenic mice were expressed as-fold ATF expression of that in wild-type mice fed with water. Asterisks indicate statistical significance (p < 0.05).
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4496697&req=5

biomolecules-05-00793-f006: Liver ATF4 and ATF6 mRNA expression. cDNA synthesized from liver RNA of wild-type and catalase−/− or gpx-1−/− transgenic mice, fed with plain water (H2O) or ethanol (alc.), was employed to determine ATF4 (A) and ATF6 (B) mRNA expression by real-time PCR. Gene expression levels in alcohol fed wild-type and untreated or alcohol-fed transgenic mice were expressed as-fold ATF expression of that in wild-type mice fed with water. Asterisks indicate statistical significance (p < 0.05).
Mentions: The transcription factors, ATF4 and ATF6, which are activated by ER stress, have been shown to regulate CHOP expression [21]. The level of ATF4 and ATF6 mRNA expression in the livers of untreated and alcohol-treated transgenic and wild-type mice was determined by real-time PCR (Figure 6). The expression of ATF4 in the liver was significantly increased in gpx-1−/− and was unchanged in catalase−/− mice, compared to wild-type mice (Figure 6A). Alcohol however significantly inhibited ATF4 mRNA expression in gpx-1−/−, but not catalase−/− or wild-type, mice (Figure 6A). No significant changes in ATF6 mRNA expression were observed in transgenic mice compared to wild-type mice (Figure 6B). Similarly, ATF6 mRNA expression was not altered by alcohol treatment in wild-type or transgenic mice (Figure 6B).

Bottom Line: Gpx-1(-/-) displayed significantly higher hepatic H2O2 levels than catalase(-/-) compared to wild-type mice, as measured by 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA).In conclusion, our findings strongly suggest that H2O2 inhibits hepcidin expression in vivo.Synergistic induction of CHOP by alcohol and H2O2, in the absence of gpx-1, stimulates liver hepcidin gene expression by ER stress independent of CREBH.

View Article: PubMed Central - PubMed

Affiliation: Department of Internal Medicine, Division of Gastroenterology/Hepatology, University of Nebraska Medical Center, Omaha, NE 68198, USA. dharrisonfindik@unmc.edu.

ABSTRACT
This study investigates the regulation of hepcidin, the key iron-regulatory molecule, by alcohol and hydrogen peroxide (H2O2) in glutathione peroxidase-1 (gpx-1(-/-)) and catalase (catalase(-/-)) knockout mice. For alcohol studies, 10% ethanol was administered in the drinking water for 7 days. Gpx-1(-/-) displayed significantly higher hepatic H2O2 levels than catalase(-/-) compared to wild-type mice, as measured by 2'-7'-dichlorodihydrofluorescein diacetate (DCFH-DA). The basal level of liver hepcidin expression was attenuated in gpx-1(-/-) mice. Alcohol increased H2O2 production in catalase(-/-) and wild-type, but not gpx-1(-/-), mice. Hepcidin expression was inhibited in alcohol-fed catalase(-/-) and wild-type mice. In contrast, alcohol elevated hepcidin expression in gpx-1(-/-) mice. Gpx-1(-/-) mice also displayed higher level of basal liver CHOP protein expression than catalase(-/-) mice. Alcohol induced CHOP and to a lesser extent GRP78/BiP expression, but not XBP1 splicing or binding of CREBH to hepcidin gene promoter, in gpx-1(-/-) mice. The up-regulation of hepatic ATF4 mRNA levels, which was observed in gpx-1(-/-) mice, was attenuated by alcohol. In conclusion, our findings strongly suggest that H2O2 inhibits hepcidin expression in vivo. Synergistic induction of CHOP by alcohol and H2O2, in the absence of gpx-1, stimulates liver hepcidin gene expression by ER stress independent of CREBH.

Show MeSH
Related in: MedlinePlus