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Adenovirus-mediated transfer of the muscle glycogen phosphorylase gene into hepatocytes confers altered regulation of glycogen metabolism.

Publication ,  Journal Article
Gómez-Foix, AM; Coats, WS; Baqué, S; Alam, T; Gerard, RD; Newgard, CB
Published in: J Biol Chem
December 15, 1992

The muscle isozyme of glycogen phosphorylase is potently activated by the allosteric ligand AMP, whereas the liver isozyme is not. In this study we have investigated the metabolic impact of expression of muscle phosphorylase in liver cells. To this end, we constructed a replication-defective, recombinant adenovirus containing the muscle glycogen phosphorylase cDNA (termed AdCMV-MGP) and used this system to infect hepatocytes in culture. AMP-activatable glycogen phosphorylase activity was increased 46-fold 6 days after infection of primary liver cells with AdCMV-MGP. Despite large increases in phosphorylase activity, glycogen levels were only slightly reduced in AdCMV-MGP-infected liver cells compared to uninfected cells or cells infected with wild-type adenovirus. The lack of correlation of phosphorylase activity and glycogen content suggests that the liver cell environment can inhibit the muscle phosphorylase isozyme. This inhibition can be overcome, however, by addition of carbonyl cyanide m-chlorophenylhydrazone (CCCP), which increases AMP levels by 30-fold and causes a much larger decrease in glycogen levels in AdCMV-MGP-infected cells than in uninfected or wild-type adenovirus-infected controls. CCCP treatment also caused a preferential decrease in glycogen content relative to glucagon treatment in AdCMV-MGP-infected hepatocytes (74% versus 11%, respectively), even though the two drugs caused equal increases in phosphorylase a activity. Introduction of muscle phosphorylase into hepatocytes therefore confers a capacity for glycogenolytic response to effectors that is not provided by the endogenous liver phosphorylase isozyme. The remarkable efficiency of adenovirus-mediated gene transfer into primary hepatocytes and the demonstration of altered regulation of glycogen metabolism as a consequence of expression of a non-cognate phosphorylase isozyme may have implications for gene therapy of glycogen storage diseases.

Duke Scholars

Published In

J Biol Chem

ISSN

0021-9258

Publication Date

December 15, 1992

Volume

267

Issue

35

Start / End Page

25129 / 25134

Location

United States

Related Subject Headings

  • Transfection
  • Rats, Wistar
  • Rats
  • Promoter Regions, Genetic
  • Phosphorylases
  • Muscles
  • Male
  • Liver Glycogen
  • Liver
  • Kinetics
 

Citation

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Gómez-Foix, A. M., Coats, W. S., Baqué, S., Alam, T., Gerard, R. D., & Newgard, C. B. (1992). Adenovirus-mediated transfer of the muscle glycogen phosphorylase gene into hepatocytes confers altered regulation of glycogen metabolism. J Biol Chem, 267(35), 25129–25134.
Gómez-Foix, A. M., W. S. Coats, S. Baqué, T. Alam, R. D. Gerard, and C. B. Newgard. “Adenovirus-mediated transfer of the muscle glycogen phosphorylase gene into hepatocytes confers altered regulation of glycogen metabolism.J Biol Chem 267, no. 35 (December 15, 1992): 25129–34.
Gómez-Foix AM, Coats WS, Baqué S, Alam T, Gerard RD, Newgard CB. Adenovirus-mediated transfer of the muscle glycogen phosphorylase gene into hepatocytes confers altered regulation of glycogen metabolism. J Biol Chem. 1992 Dec 15;267(35):25129–34.
Gómez-Foix AM, Coats WS, Baqué S, Alam T, Gerard RD, Newgard CB. Adenovirus-mediated transfer of the muscle glycogen phosphorylase gene into hepatocytes confers altered regulation of glycogen metabolism. J Biol Chem. 1992 Dec 15;267(35):25129–25134.

Published In

J Biol Chem

ISSN

0021-9258

Publication Date

December 15, 1992

Volume

267

Issue

35

Start / End Page

25129 / 25134

Location

United States

Related Subject Headings

  • Transfection
  • Rats, Wistar
  • Rats
  • Promoter Regions, Genetic
  • Phosphorylases
  • Muscles
  • Male
  • Liver Glycogen
  • Liver
  • Kinetics