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CMZ reversed chronic ethanol-induced disturbance of PPAR-α possibly by suppressing oxidative stress and PGC-1α acetylation, and activating the MAPK and GSK3β pathway.

Zeng T, Zhang CL, Song FY, Zhao XL, Xie KQ - PLoS ONE (2014)

Bottom Line: Chronic ethanol exposure led to significant decrease of the mRNA and protein levels of peroxisome proliferator-activated receptor α (PPAR-α), which was blocked by CMZ co-treatment.CMZ co-treatment suppressed ethanol-induced oxidative stress, overproduction of tumor necrosis α (TNF-α), and decrease of protein levels of the PPAR-α co-activators including p300 and deacetylated PGC1-α.These results suggested that CMZ suppressed chronic ethanol-induced oxidative stress, TNF-α overproduction, decline of p300 protein level and deacetylation of PGC1-α, and activated AMPK, MAPK, and PI3K/Akt/GSK3β pathway, which might contribute to the activation of PPAR-α and account for the protection of CMZ against AFL.

View Article: PubMed Central - PubMed

Affiliation: Institute of Toxicology, School of Public Health, Shandong University, Jinan City, Shandong Province, People's Republic of China.

ABSTRACT

Background: Cytochrome P4502E1 (CYP2E1) has been suggested to play critical roles in the pathogenesis of alcoholic fatty liver (AFL), but the underlying mechanisms remains unclear. The current study was designed to evaluate whether CYP2E1 suppression by chlormethiazole (CMZ) could suppress AFL in mice, and to explore the underlying mechanisms.

Methods: Mice were treated with or without CMZ (50 mg/kg bw, i.p.) and subjected to liquid diet with or without ethanol (5%, w/v) for 4 weeks. Biochemical parameters were measured using commercial kits. The protein and mRNA levels were detected by western blot and qPCR, respectively. Histopathology and immunohistochemical assay were performed with routine methods.

Results: CYP2E1 inhibition by CMZ completely blocked AFL in mice, shown as the decline of the hepatic and serum triglyceride levels, and the fewer fat droplets in the liver sections. Chronic ethanol exposure led to significant decrease of the mRNA and protein levels of peroxisome proliferator-activated receptor α (PPAR-α), which was blocked by CMZ co-treatment. CMZ co-treatment suppressed ethanol-induced oxidative stress, overproduction of tumor necrosis α (TNF-α), and decrease of protein levels of the PPAR-α co-activators including p300 and deacetylated PGC1-α. Furthermore, CMZ co-treatment led to the activation of AMP-activated protein kinase (AMPK), mitogen-activated protein kinase (MAPK), and PI3K/Akt/GSK3β pathway. However, chronic ethanol-induced decline of acyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) protein levels was partially restored by CMZ, while the activation of autophagy appeared to be suppressed by CMZ.

Conclusion: These results suggested that CMZ suppressed chronic ethanol-induced oxidative stress, TNF-α overproduction, decline of p300 protein level and deacetylation of PGC1-α, and activated AMPK, MAPK, and PI3K/Akt/GSK3β pathway, which might contribute to the activation of PPAR-α and account for the protection of CMZ against AFL.

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Related in: MedlinePlus

Effects of ethanol and CMZ on the mRNA and protein levels of n-SREBP-1, phospho-ACCser79, ACC, FAS, and DGAT2.(a) Representative western blot bands for n-SREBP-1, phospho-ACCser79, ACC, FAS, and DGAT2. (b) Quantitative data analyses. (c) The mRNA levels of SREBP-1, ACC, and FAS. Data were presented as mean ± SD from at least 3 independent experiments, and expressed as the percentage of the control. *P<0.05, **P<0.01, compared with control group; #P<0.05, ##P<0.01, compared with ethanol group.
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pone-0098658-g009: Effects of ethanol and CMZ on the mRNA and protein levels of n-SREBP-1, phospho-ACCser79, ACC, FAS, and DGAT2.(a) Representative western blot bands for n-SREBP-1, phospho-ACCser79, ACC, FAS, and DGAT2. (b) Quantitative data analyses. (c) The mRNA levels of SREBP-1, ACC, and FAS. Data were presented as mean ± SD from at least 3 independent experiments, and expressed as the percentage of the control. *P<0.05, **P<0.01, compared with control group; #P<0.05, ##P<0.01, compared with ethanol group.

Mentions: The mRNA and protein levels of SREBP-1 and two important enzymes involved in fatty acid synthesis (ACC and FAS) were detected and the results were shown in Fig.9. We only detected the mature form of SREBP-1 (n-SREBP-1, 68 kD), but not the precursor form of SREBP-1 (125 kD). The mRNA and protein levels of SREBP-1 were not significantly altered in the liver of ethanol group mice when compared with those of control group mice. However, chronic ethanol intake resulted in remarkable decline of the protein levels of ACC, phospho-ACCser79, and FAS, which was significantly suppressed by CMZ co-treatment. The protein level of diacylglycerol acyltransferase 2 (DGAT2), the rate-limiting enzyme in TG synthesis, was significantly increased in ethanol group mice liver, which was further increased in CMZ/ethanol group mice liver.


CMZ reversed chronic ethanol-induced disturbance of PPAR-α possibly by suppressing oxidative stress and PGC-1α acetylation, and activating the MAPK and GSK3β pathway.

Zeng T, Zhang CL, Song FY, Zhao XL, Xie KQ - PLoS ONE (2014)

Effects of ethanol and CMZ on the mRNA and protein levels of n-SREBP-1, phospho-ACCser79, ACC, FAS, and DGAT2.(a) Representative western blot bands for n-SREBP-1, phospho-ACCser79, ACC, FAS, and DGAT2. (b) Quantitative data analyses. (c) The mRNA levels of SREBP-1, ACC, and FAS. Data were presented as mean ± SD from at least 3 independent experiments, and expressed as the percentage of the control. *P<0.05, **P<0.01, compared with control group; #P<0.05, ##P<0.01, compared with ethanol group.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4043914&req=5

pone-0098658-g009: Effects of ethanol and CMZ on the mRNA and protein levels of n-SREBP-1, phospho-ACCser79, ACC, FAS, and DGAT2.(a) Representative western blot bands for n-SREBP-1, phospho-ACCser79, ACC, FAS, and DGAT2. (b) Quantitative data analyses. (c) The mRNA levels of SREBP-1, ACC, and FAS. Data were presented as mean ± SD from at least 3 independent experiments, and expressed as the percentage of the control. *P<0.05, **P<0.01, compared with control group; #P<0.05, ##P<0.01, compared with ethanol group.
Mentions: The mRNA and protein levels of SREBP-1 and two important enzymes involved in fatty acid synthesis (ACC and FAS) were detected and the results were shown in Fig.9. We only detected the mature form of SREBP-1 (n-SREBP-1, 68 kD), but not the precursor form of SREBP-1 (125 kD). The mRNA and protein levels of SREBP-1 were not significantly altered in the liver of ethanol group mice when compared with those of control group mice. However, chronic ethanol intake resulted in remarkable decline of the protein levels of ACC, phospho-ACCser79, and FAS, which was significantly suppressed by CMZ co-treatment. The protein level of diacylglycerol acyltransferase 2 (DGAT2), the rate-limiting enzyme in TG synthesis, was significantly increased in ethanol group mice liver, which was further increased in CMZ/ethanol group mice liver.

Bottom Line: Chronic ethanol exposure led to significant decrease of the mRNA and protein levels of peroxisome proliferator-activated receptor α (PPAR-α), which was blocked by CMZ co-treatment.CMZ co-treatment suppressed ethanol-induced oxidative stress, overproduction of tumor necrosis α (TNF-α), and decrease of protein levels of the PPAR-α co-activators including p300 and deacetylated PGC1-α.These results suggested that CMZ suppressed chronic ethanol-induced oxidative stress, TNF-α overproduction, decline of p300 protein level and deacetylation of PGC1-α, and activated AMPK, MAPK, and PI3K/Akt/GSK3β pathway, which might contribute to the activation of PPAR-α and account for the protection of CMZ against AFL.

View Article: PubMed Central - PubMed

Affiliation: Institute of Toxicology, School of Public Health, Shandong University, Jinan City, Shandong Province, People's Republic of China.

ABSTRACT

Background: Cytochrome P4502E1 (CYP2E1) has been suggested to play critical roles in the pathogenesis of alcoholic fatty liver (AFL), but the underlying mechanisms remains unclear. The current study was designed to evaluate whether CYP2E1 suppression by chlormethiazole (CMZ) could suppress AFL in mice, and to explore the underlying mechanisms.

Methods: Mice were treated with or without CMZ (50 mg/kg bw, i.p.) and subjected to liquid diet with or without ethanol (5%, w/v) for 4 weeks. Biochemical parameters were measured using commercial kits. The protein and mRNA levels were detected by western blot and qPCR, respectively. Histopathology and immunohistochemical assay were performed with routine methods.

Results: CYP2E1 inhibition by CMZ completely blocked AFL in mice, shown as the decline of the hepatic and serum triglyceride levels, and the fewer fat droplets in the liver sections. Chronic ethanol exposure led to significant decrease of the mRNA and protein levels of peroxisome proliferator-activated receptor α (PPAR-α), which was blocked by CMZ co-treatment. CMZ co-treatment suppressed ethanol-induced oxidative stress, overproduction of tumor necrosis α (TNF-α), and decrease of protein levels of the PPAR-α co-activators including p300 and deacetylated PGC1-α. Furthermore, CMZ co-treatment led to the activation of AMP-activated protein kinase (AMPK), mitogen-activated protein kinase (MAPK), and PI3K/Akt/GSK3β pathway. However, chronic ethanol-induced decline of acyl-CoA carboxylase (ACC) and fatty acid synthase (FAS) protein levels was partially restored by CMZ, while the activation of autophagy appeared to be suppressed by CMZ.

Conclusion: These results suggested that CMZ suppressed chronic ethanol-induced oxidative stress, TNF-α overproduction, decline of p300 protein level and deacetylation of PGC1-α, and activated AMPK, MAPK, and PI3K/Akt/GSK3β pathway, which might contribute to the activation of PPAR-α and account for the protection of CMZ against AFL.

Show MeSH
Related in: MedlinePlus