CD73 (ecto-5′-nucleotidase) hepatocyte levels differ across mouse strains and contribute to mallory-denk body formation

Authors

  • Natasha T. Snider,

    Corresponding author
    1. Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
    • Address reprint requests to: Natasha Snider, Ph.D., Department of Molecular & Integrative Physiology, University of Michigan Medical School, 7720 Medical Science II, 1301 East Catherine Street, Ann Arbor, MI 48109-5622. E-mail: nsnider@umich.edu; fax: 734-936-8813.

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  • Nicholas W. Griggs,

    1. Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
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  • Amika Singla,

    1. Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
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  • David S. Moons,

    1. Department of Pathology, University of Michigan Medical School, Ann Arbor, MI
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  • Sujith V.W. Weerasinghe,

    1. Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
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  • Anna S. Lok,

    1. Department of Medicine, University of Michigan Medical School, Ann Arbor, MI
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  • Chunhai Ruan,

    1. Department of Medicine, University of Michigan Medical School, Ann Arbor, MI
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  • Charles F. Burant,

    1. Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
    2. Department of Medicine, University of Michigan Medical School, Ann Arbor, MI
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  • Hari S. Conjeevaram,

    1. Department of Medicine, University of Michigan Medical School, Ann Arbor, MI
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  • M. Bishr Omary

    1. Department of Molecular & Integrative Physiology, University of Michigan Medical School, Ann Arbor, MI
    2. Department of Medicine, University of Michigan Medical School, Ann Arbor, MI
    3. VA Ann Arbor Healthcare System, Ann Arbor, MI
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  • Potential conflict of interest: Nothing to report.

  • This work was supported by the National Institutes of Health (grant nos.: R01 DK52951 [to M.B.O.] and K01 DK093776 [to N.T.S.]). and Department of Veterans Affairs Merit Review Award (to M.B.O.). This work utilized Core Services (supported by NIH grant nos.: DK089503 and DK034933; to the University of Michigan).

Abstract

Formation of hepatocyte Mallory-Denk bodies (MDBs), which are aggregates of keratins 8 and 18 (K8/K18), ubiquitin, and the ubiquitin-binding protein, p62, has a genetic predisposition component in humans and mice. We tested the hypothesis that metabolomic profiling of MDB-susceptible C57BL and MDB-resistant C3H mouse strains can illuminate MDB-associated pathways. Using both targeted and unbiased metabolomic analyses, we demonstrated significant differences in intermediates of purine metabolism. Further analysis revealed that C3H and C57BL livers differ significantly in messenger RNA (mRNA) level, protein expression, and enzymatic activity of the adenosine-generating enzyme, ecto-5′-nucleotidase (CD73), which was significantly lower in C57BL livers. CD73 mRNA levels were also dramatically decreased in human liver biopsies from hepatitis C and nonalcoholic fatty liver disease patients. Feeding mice with a diet containing the MDB-inducing agent, 3,5-diethoxycarbonyl-1,4-dihydrocollidine (DDC), significantly decreased CD73 protein and activity in C57BL livers and resulted in loss of plasma membrane CD73 expression and activity in isolated mouse hepatocytes. To further examine the role of CD73 in MDB formation in vivo, we fed wild-type (WT) and CD73−/− mice a DDC-containing diet. Liver enlargement, p62 induction, and disappearance of the K8/K18 cytoskeleton were attenuated in CD73−/−, compared to WT livers. MDB formation, as assessed by biochemical and immunofluorescence detection of keratin and ubiquitin complexes, was nearly absent in CD73−/− mice. Conclusion: Purine metabolism and CD73 expression are linked to susceptibility to MDB formation in livers of different mouse strains. Expression of the adenosine-generating enzyme, CD73, contributes to experimental MDB induction and is highly regulated in MDB-associated liver injury in mice and in chronic human liver disease. (Hepatology 2013;58:1790–1800)

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