Correction of glycogen storage disease type II by enzyme replacement with a recombinant human acid maltase produced by over-expression in a CHO-DHFR(neg) cell line

Frank Martiniuk, Agnes Chen, Vincent Donnabella, Eleni Arvanitopoulos, Alfred E. Slonim, Nina Raben, Paul Plotz, William N. Rom

Research output: Contribution to journalArticle

Abstract

Inherited genetic deficiency of lysosomal acid alpha glucosidase or acid maltase (GAA) results in the autosomal recessive glycogen storage disease type II (GSD II). To investigate whether we could generate a functional recombinant human GAA (rhGAA) for enzyme replacement therapy, we subcloned the cDNAs for human GAA and mouse dihydrofolate reductase (DHFR) into DHFR(neg) Chinese hamster ovary cells and established a stable cotransformant that expressed rhGAA. We cultured the recombinant cells in media with progressively increasing concentrations of methotrexate and found that human GAA enzyme activity increased to over 2,000 IU per gram protein. Importantly, the human GAA enzyme activity correlated to equivalent amounts of human GAA protein by rocketimmunoelectrophoresis. We confirmed that the human GAA enzyme activity corresponded to an amplification in human GAA mRNA by Northern analysis and human GAA cDNA copy number by Southern analysis. Exposing the rhGAA to human GSDII fibroblast cells or patient's lymphocytes or monocytes resulted in uptake of the rhGAA and reversal of the enzymatic defect. Mannose-6-phosphate in the media blocked uptake. GAA -/- mice were treated with the rhGAA at 1 mg/kg, which resulted in heterozygous levels of GAA in tissues, most notably skeletal muscle, heart and diaphragm after two infusions. More importantly, after multiple infusions, hind, and fore-limb muscle weakness was reversed. This rhGAA would be ideal for enzyme replacement therapy in GSD II. (C) 2000 Academic Press.

Original languageEnglish (US)
Pages (from-to)917-923
Number of pages7
JournalBiochemical and Biophysical Research Communications
Volume276
Issue number3
DOIs
StatePublished - Oct 5 2000
Externally publishedYes

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Keywords

  • Acid maltase
  • Glycogen storage disease type II
  • Methotrexate
  • Over-expression CHO cell line
  • Pompe's disease
  • Recombinant human acid maltase (rhGAA)

ASJC Scopus subject areas

  • Biochemistry
  • Biophysics
  • Molecular Biology

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