Retrovirus vector-mediated correction and cross-correction of lysosomal alpha-mannosidase deficiency in human and feline fibroblasts.
Lysosomal alpha-mannosidase (EC 3.2.1.24) is an exoglycosidase in the glycoprotein degradation pathway. A deficiency of this enzyme causes the lysosomal storage disease alpha-mannosidosis. Retrovirus vector transfer of a new human alpha-mannosidase cDNA resulted in high-level expression of alpha-mannosidase enzymatic activity in deficient human and feline fibroblasts. The expressed alpha-mannosidase had the same biochemical properties (thermal stability, pH profile, inhibitor/activator sensitivity) as the native enzyme expressed in normal cells. The transferred enzyme colocalized with a control lysosomal hydrolase in cell fractionation experiments. The vector-encoded enzyme also was released at high levels from the corrected cells, and was taken up by untreated mutant cells via the mannose 6-phosphate receptor-mediated endocytic pathway (cross-correction). It is envisioned that genetic correction of a subset of cells (e.g., hematopoietic stem cells) in patients will provide a source of corrective enzyme for other affected tissues in this multisystem disease. Development of a vector expressing high levels of alpha-mannosidase that cross-corrects mutant cells will enable somatic gene transfer experiments in the cat model of human alpha-mannosidosis.
Sun
H
H
Laboratory of Pathology, School of Veterinary Medicine, University of Pennsylvania, Philadelphia 19104, USA.
Yang
M
M
Haskins
M E
ME
Patterson
D F
DF
Wolfe
J H
JH
D000818:Animals; D002415:Cats; D002460:Cell Line; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D018014:Gene Transfer Techniques; D005822:Genetic Vectors; D005966:Glucuronidase / Q000378:metabolism; D006367:HeLa Cells; D006801:Humans; D008247:Lysosomes / Q000201:enzymology; D008361:Mannosidases / Q000172:deficiency / Q000235:genetics* / Q000378:metabolism; D051379:Mice; D009154:Mutation; D012190:Retroviridae; D014407:Tumor Cells, Cultured; D043323:alpha-Mannosidase; D008363:alpha-Mannosidosis / Q000628:therapy
D008361:Mannosidases; D043323:alpha-Mannosidase; D005966:Glucuronidase