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Enhanced Production of Adenosine Triphosphate by Pharmacological Activation of Adenosine Monophosphate-Activated Protein Kinase Ameliorates Acetaminophen-Induced Liver Injury.

Hwang JH, Kim YH, Noh JR, Choi DH, Kim KS, Lee CH - Mol. Cells (2015)

Bottom Line: We found that the decrease in active phosphorylation of AMPK in response to APAP correlates with decreased ATP levels, in vivo.In contrast, inhibition of glycolysis by 2-deoxy-glucose eliminated the beneficial effects of A769662 on APAP-mediated liver injury.In conclusion, A769662 can effectively protect mice against APAP-induced liver injury through ATP synthesis by anaerobic glycolysis.

View Article: PubMed Central - PubMed

Affiliation: Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), University of Science and Technology (UST), Daejeon 305-806, Korea.

ABSTRACT
The hepatic cell death induced by acetaminophen (APAP) is closely related to cellular adenosine triphosphate (ATP) depletion, which is mainly caused by mitochondrial dysfunction. Adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a key sensor of low energy status. AMPK regulates metabolic homeostasis by stimulating catabolic metabolism and suppressing anabolic pathways to increase cellular energy levels. We found that the decrease in active phosphorylation of AMPK in response to APAP correlates with decreased ATP levels, in vivo. Therefore, we hypothesized that the enhanced production of ATP via AMPK stimulation can lead to amelioration of APAP-induced liver failure. A769662, an allosteric activator of AMPK, produced a strong synergistic effect on AMPK Thr172 phosphorylation with APAP in primary hepatocytes and liver tissue. Interestingly, activation of AMPK by A769662 ameliorated the APAP-induced hepatotoxicity in C57BL/6N mice treated with APAP at a dose of 400 mg/kg intraperitoneally. However, mice treated with APAP alone developed massive centrilobular necrosis, and APAP increased their serum alanine aminotransferase and aspartate aminotransferase levels. Furthermore, A769662 administration prevented the loss of intracellular ATP without interfering with the APAP-mediated reduction of mitochondrial dysfunction. In contrast, inhibition of glycolysis by 2-deoxy-glucose eliminated the beneficial effects of A769662 on APAP-mediated liver injury. In conclusion, A769662 can effectively protect mice against APAP-induced liver injury through ATP synthesis by anaerobic glycolysis. Furthermore, stimulation of AMPK may have potential therapeutic application for APAP overdose.

No MeSH data available.


Related in: MedlinePlus

Time-dependent changes in adenosine triphosphate (ATP) and adenosine monophosphate-activated protein kinase (AMPK) phosphorylation by acetaminophen (APAP). Eight-week-old C57BL/6N male mice were intraperitoneally administered 400 mg/kg APAP. Liver tissue samples were collected at indicated time points following APAP treatment. (A) ATP concentration was measured in the liver samples from each group. (B) AMPK activation was estimated by immunoblot analysis by using antibodies (Abs) against the phosphorylated (pT172) or total AMPK; n = 5, *P < 0.05, ***P < 0.001 as compared to time zero.
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f1-molce-38-10-843: Time-dependent changes in adenosine triphosphate (ATP) and adenosine monophosphate-activated protein kinase (AMPK) phosphorylation by acetaminophen (APAP). Eight-week-old C57BL/6N male mice were intraperitoneally administered 400 mg/kg APAP. Liver tissue samples were collected at indicated time points following APAP treatment. (A) ATP concentration was measured in the liver samples from each group. (B) AMPK activation was estimated by immunoblot analysis by using antibodies (Abs) against the phosphorylated (pT172) or total AMPK; n = 5, *P < 0.05, ***P < 0.001 as compared to time zero.

Mentions: It is well known that APAP-mediated hepatotoxicity causes depletion of hepatic ATP levels by inhibiting mitochondrial function (Jaeschke and Bajt, 2006). In addition, it has been shown that stimulation of AMPK can increase the ATP level in several tissues (Hardie and Sakamoto, 2006). Therefore, we hypothesized that ATP depletion might be caused by the deregulation of AMPK activation. Male C57BL/6N mice were treated with a single dose of APAP (400 mg/kg body weight) and the relationship between ATP levels and AMPK phosphorylation was estimated. Following APAP administration, ATP loss occurred rapidly while recovery was slow (Fig. 1A). Interestingly, active phosphorylation of AMPK declined at the same time point and with a similar pattern (Fig. 1B), suggesting that ATP depletion by APAP might correlate with inhibition of AMPK activity.


Enhanced Production of Adenosine Triphosphate by Pharmacological Activation of Adenosine Monophosphate-Activated Protein Kinase Ameliorates Acetaminophen-Induced Liver Injury.

Hwang JH, Kim YH, Noh JR, Choi DH, Kim KS, Lee CH - Mol. Cells (2015)

Time-dependent changes in adenosine triphosphate (ATP) and adenosine monophosphate-activated protein kinase (AMPK) phosphorylation by acetaminophen (APAP). Eight-week-old C57BL/6N male mice were intraperitoneally administered 400 mg/kg APAP. Liver tissue samples were collected at indicated time points following APAP treatment. (A) ATP concentration was measured in the liver samples from each group. (B) AMPK activation was estimated by immunoblot analysis by using antibodies (Abs) against the phosphorylated (pT172) or total AMPK; n = 5, *P < 0.05, ***P < 0.001 as compared to time zero.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4625065&req=5

f1-molce-38-10-843: Time-dependent changes in adenosine triphosphate (ATP) and adenosine monophosphate-activated protein kinase (AMPK) phosphorylation by acetaminophen (APAP). Eight-week-old C57BL/6N male mice were intraperitoneally administered 400 mg/kg APAP. Liver tissue samples were collected at indicated time points following APAP treatment. (A) ATP concentration was measured in the liver samples from each group. (B) AMPK activation was estimated by immunoblot analysis by using antibodies (Abs) against the phosphorylated (pT172) or total AMPK; n = 5, *P < 0.05, ***P < 0.001 as compared to time zero.
Mentions: It is well known that APAP-mediated hepatotoxicity causes depletion of hepatic ATP levels by inhibiting mitochondrial function (Jaeschke and Bajt, 2006). In addition, it has been shown that stimulation of AMPK can increase the ATP level in several tissues (Hardie and Sakamoto, 2006). Therefore, we hypothesized that ATP depletion might be caused by the deregulation of AMPK activation. Male C57BL/6N mice were treated with a single dose of APAP (400 mg/kg body weight) and the relationship between ATP levels and AMPK phosphorylation was estimated. Following APAP administration, ATP loss occurred rapidly while recovery was slow (Fig. 1A). Interestingly, active phosphorylation of AMPK declined at the same time point and with a similar pattern (Fig. 1B), suggesting that ATP depletion by APAP might correlate with inhibition of AMPK activity.

Bottom Line: We found that the decrease in active phosphorylation of AMPK in response to APAP correlates with decreased ATP levels, in vivo.In contrast, inhibition of glycolysis by 2-deoxy-glucose eliminated the beneficial effects of A769662 on APAP-mediated liver injury.In conclusion, A769662 can effectively protect mice against APAP-induced liver injury through ATP synthesis by anaerobic glycolysis.

View Article: PubMed Central - PubMed

Affiliation: Laboratory Animal Resource Center, Korea Research Institute of Bioscience and Biotechnology (KRIBB), University of Science and Technology (UST), Daejeon 305-806, Korea.

ABSTRACT
The hepatic cell death induced by acetaminophen (APAP) is closely related to cellular adenosine triphosphate (ATP) depletion, which is mainly caused by mitochondrial dysfunction. Adenosine monophosphate (AMP)-activated protein kinase (AMPK) is a key sensor of low energy status. AMPK regulates metabolic homeostasis by stimulating catabolic metabolism and suppressing anabolic pathways to increase cellular energy levels. We found that the decrease in active phosphorylation of AMPK in response to APAP correlates with decreased ATP levels, in vivo. Therefore, we hypothesized that the enhanced production of ATP via AMPK stimulation can lead to amelioration of APAP-induced liver failure. A769662, an allosteric activator of AMPK, produced a strong synergistic effect on AMPK Thr172 phosphorylation with APAP in primary hepatocytes and liver tissue. Interestingly, activation of AMPK by A769662 ameliorated the APAP-induced hepatotoxicity in C57BL/6N mice treated with APAP at a dose of 400 mg/kg intraperitoneally. However, mice treated with APAP alone developed massive centrilobular necrosis, and APAP increased their serum alanine aminotransferase and aspartate aminotransferase levels. Furthermore, A769662 administration prevented the loss of intracellular ATP without interfering with the APAP-mediated reduction of mitochondrial dysfunction. In contrast, inhibition of glycolysis by 2-deoxy-glucose eliminated the beneficial effects of A769662 on APAP-mediated liver injury. In conclusion, A769662 can effectively protect mice against APAP-induced liver injury through ATP synthesis by anaerobic glycolysis. Furthermore, stimulation of AMPK may have potential therapeutic application for APAP overdose.

No MeSH data available.


Related in: MedlinePlus