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Energy determinants GAPDH and NDPK act as genetic modifiers for hepatocyte inclusion formation.

Snider NT, Weerasinghe SV, Singla A, Leonard JM, Hanada S, Andrews PC, Lok AS, Omary MB - J. Cell Biol. (2011)

Bottom Line: Prominent histological features of some chronic human liver diseases are hepatocyte ballooning and Mallory-Denk bodies.GAPDH knockdown depleted bioenergetic and antioxidant enzymes and elevated hepatocyte ROS, whereas GAPDH overexpression decreased hepatocyte ROS.We propose that GAPDH and NDPK are genetic modifiers of murine DDC-induced liver injury and potentially human liver disease.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA. nsnider@umich.edu

ABSTRACT
Genetic factors impact liver injury susceptibility and disease progression. Prominent histological features of some chronic human liver diseases are hepatocyte ballooning and Mallory-Denk bodies. In mice, these features are induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) in a strain-dependent manner, with the C57BL and C3H strains showing high and low susceptibility, respectively. To identify modifiers of DDC-induced liver injury, we compared C57BL and C3H mice using proteomic, biochemical, and cell biological tools. DDC elevated reactive oxygen species (ROS) and oxidative stress enzymes preferentially in C57BL livers and isolated hepatocytes. C57BL livers and hepatocytes also manifested significant down-regulation, aggregation, and nuclear translocation of glyceraldehyde 3-phosphate dehydrogenase (GAPDH). GAPDH knockdown depleted bioenergetic and antioxidant enzymes and elevated hepatocyte ROS, whereas GAPDH overexpression decreased hepatocyte ROS. On the other hand, C3H livers had higher expression and activity of the energy-generating nucleoside-diphosphate kinase (NDPK), and knockdown of hepatocyte NDPK augmented DDC-induced ROS formation. Consistent with these findings, cirrhotic, but not normal, human livers contained GAPDH aggregates and NDPK complexes. We propose that GAPDH and NDPK are genetic modifiers of murine DDC-induced liver injury and potentially human liver disease.

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Compromised energetics and redox cycling contribute to MDB formation in C57BL mice. DDC causes oxidative stress in vivo, as indicated by the significant induction of liver GST and CBR3 expression, and ex vivo in isolated hepatocytes, as indicated by the accumulation of intracellular ROS. Elevated ROS promotes aggregation and nuclear translocation of GAPDH in the livers of DDC-fed mice and in DDC-treated isolated hepatocytes. Ex vivo DDC treatment of hepatocytes causes a significant down-regulation of GAPDH. Furthermore, GAPDH is a central regulator of energy metabolism and oxidative stress–related enzymes, including NDPK, FAH, CA3, and PRDX6, as GAPDH knockdown leads to significant decreases in the expression of these proteins and mimics the effect of DDC. Therefore, diminished GAPDH expression and function lead to a bioenergetic and redox crisis, compromising energy-dependent protein processing pathways and ultimately leading to MDB formation. The glycolysis-stimulating agent pioglitazone reverses the GAPDH down-regulation and nuclear translocation.
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fig10: Compromised energetics and redox cycling contribute to MDB formation in C57BL mice. DDC causes oxidative stress in vivo, as indicated by the significant induction of liver GST and CBR3 expression, and ex vivo in isolated hepatocytes, as indicated by the accumulation of intracellular ROS. Elevated ROS promotes aggregation and nuclear translocation of GAPDH in the livers of DDC-fed mice and in DDC-treated isolated hepatocytes. Ex vivo DDC treatment of hepatocytes causes a significant down-regulation of GAPDH. Furthermore, GAPDH is a central regulator of energy metabolism and oxidative stress–related enzymes, including NDPK, FAH, CA3, and PRDX6, as GAPDH knockdown leads to significant decreases in the expression of these proteins and mimics the effect of DDC. Therefore, diminished GAPDH expression and function lead to a bioenergetic and redox crisis, compromising energy-dependent protein processing pathways and ultimately leading to MDB formation. The glycolysis-stimulating agent pioglitazone reverses the GAPDH down-regulation and nuclear translocation.

Mentions: In the present study, we tested the hypothesis that genetic factors critically modulate susceptibility to hepatocyte injury in a mouse MDB model. We began with a global approach using 2D DIGE comparison of the basal protein expression levels and DDC-induced changes in livers of C3H (MDB resistant) and C57BL (MDB susceptible) mouse strains. Next, the 2D DIGE-validated findings were used as a starting point to evaluate the status of the most likely candidate proteins and signaling pathways ex vivo in hepatocytes and in vivo in mouse and human livers. Our findings indicate that MDB susceptibility is likely related to basal deficiencies in energy metabolism pathways that are intensified by elevated oxidative stress, ultimately resulting in compromised energy-dependent protein folding/degradation responses (Fig. 10). We propose a central upstream role for GAPDH and its oxidative stress–induced aggregation and nuclear translocation in liver injury–induced hepatocyte inclusion formation. The changes in GAPDH are unlikely to be unique to alcohol-related liver injury because analysis of liver explants from patients with other etiologies of end-stage liver disease also had accumulation of aggregated GAPDH (unpublished data).


Energy determinants GAPDH and NDPK act as genetic modifiers for hepatocyte inclusion formation.

Snider NT, Weerasinghe SV, Singla A, Leonard JM, Hanada S, Andrews PC, Lok AS, Omary MB - J. Cell Biol. (2011)

Compromised energetics and redox cycling contribute to MDB formation in C57BL mice. DDC causes oxidative stress in vivo, as indicated by the significant induction of liver GST and CBR3 expression, and ex vivo in isolated hepatocytes, as indicated by the accumulation of intracellular ROS. Elevated ROS promotes aggregation and nuclear translocation of GAPDH in the livers of DDC-fed mice and in DDC-treated isolated hepatocytes. Ex vivo DDC treatment of hepatocytes causes a significant down-regulation of GAPDH. Furthermore, GAPDH is a central regulator of energy metabolism and oxidative stress–related enzymes, including NDPK, FAH, CA3, and PRDX6, as GAPDH knockdown leads to significant decreases in the expression of these proteins and mimics the effect of DDC. Therefore, diminished GAPDH expression and function lead to a bioenergetic and redox crisis, compromising energy-dependent protein processing pathways and ultimately leading to MDB formation. The glycolysis-stimulating agent pioglitazone reverses the GAPDH down-regulation and nuclear translocation.
© Copyright Policy - openaccess
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3198167&req=5

fig10: Compromised energetics and redox cycling contribute to MDB formation in C57BL mice. DDC causes oxidative stress in vivo, as indicated by the significant induction of liver GST and CBR3 expression, and ex vivo in isolated hepatocytes, as indicated by the accumulation of intracellular ROS. Elevated ROS promotes aggregation and nuclear translocation of GAPDH in the livers of DDC-fed mice and in DDC-treated isolated hepatocytes. Ex vivo DDC treatment of hepatocytes causes a significant down-regulation of GAPDH. Furthermore, GAPDH is a central regulator of energy metabolism and oxidative stress–related enzymes, including NDPK, FAH, CA3, and PRDX6, as GAPDH knockdown leads to significant decreases in the expression of these proteins and mimics the effect of DDC. Therefore, diminished GAPDH expression and function lead to a bioenergetic and redox crisis, compromising energy-dependent protein processing pathways and ultimately leading to MDB formation. The glycolysis-stimulating agent pioglitazone reverses the GAPDH down-regulation and nuclear translocation.
Mentions: In the present study, we tested the hypothesis that genetic factors critically modulate susceptibility to hepatocyte injury in a mouse MDB model. We began with a global approach using 2D DIGE comparison of the basal protein expression levels and DDC-induced changes in livers of C3H (MDB resistant) and C57BL (MDB susceptible) mouse strains. Next, the 2D DIGE-validated findings were used as a starting point to evaluate the status of the most likely candidate proteins and signaling pathways ex vivo in hepatocytes and in vivo in mouse and human livers. Our findings indicate that MDB susceptibility is likely related to basal deficiencies in energy metabolism pathways that are intensified by elevated oxidative stress, ultimately resulting in compromised energy-dependent protein folding/degradation responses (Fig. 10). We propose a central upstream role for GAPDH and its oxidative stress–induced aggregation and nuclear translocation in liver injury–induced hepatocyte inclusion formation. The changes in GAPDH are unlikely to be unique to alcohol-related liver injury because analysis of liver explants from patients with other etiologies of end-stage liver disease also had accumulation of aggregated GAPDH (unpublished data).

Bottom Line: Prominent histological features of some chronic human liver diseases are hepatocyte ballooning and Mallory-Denk bodies.GAPDH knockdown depleted bioenergetic and antioxidant enzymes and elevated hepatocyte ROS, whereas GAPDH overexpression decreased hepatocyte ROS.We propose that GAPDH and NDPK are genetic modifiers of murine DDC-induced liver injury and potentially human liver disease.

View Article: PubMed Central - HTML - PubMed

Affiliation: Department of Molecular and Integrative Physiology, University of Michigan, Ann Arbor, MI 48109, USA. nsnider@umich.edu

ABSTRACT
Genetic factors impact liver injury susceptibility and disease progression. Prominent histological features of some chronic human liver diseases are hepatocyte ballooning and Mallory-Denk bodies. In mice, these features are induced by 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC) in a strain-dependent manner, with the C57BL and C3H strains showing high and low susceptibility, respectively. To identify modifiers of DDC-induced liver injury, we compared C57BL and C3H mice using proteomic, biochemical, and cell biological tools. DDC elevated reactive oxygen species (ROS) and oxidative stress enzymes preferentially in C57BL livers and isolated hepatocytes. C57BL livers and hepatocytes also manifested significant down-regulation, aggregation, and nuclear translocation of glyceraldehyde 3-phosphate dehydrogenase (GAPDH). GAPDH knockdown depleted bioenergetic and antioxidant enzymes and elevated hepatocyte ROS, whereas GAPDH overexpression decreased hepatocyte ROS. On the other hand, C3H livers had higher expression and activity of the energy-generating nucleoside-diphosphate kinase (NDPK), and knockdown of hepatocyte NDPK augmented DDC-induced ROS formation. Consistent with these findings, cirrhotic, but not normal, human livers contained GAPDH aggregates and NDPK complexes. We propose that GAPDH and NDPK are genetic modifiers of murine DDC-induced liver injury and potentially human liver disease.

Show MeSH
Related in: MedlinePlus