Evaluation of pathological manifestations of disease in mucopolysaccharidosis VII mice after neonatal hepatic gene therapy.
Mucopolysaccharidosis VII (MPS VII) is a lysosomal storage disease caused by beta-glucuronidase (GUSB) deficiency. Intravenous injection of a retroviral vector expressing canine GUSB into neonatal MPS VII mice resulted in transduction of 6 to 35% of hepatocytes, which secreted GUSB into blood. Serum GUSB activity was stable for 6 months at 600 (low expression) to 10,000 (high expression) U/ml, and enzyme was modified appropriately with mannose 6-phosphate. The average serum GUSB activity (3531 U/ml) is the highest long-term expression reported for MPS VII mice after gene therapy. Secreted enzyme was taken up by other tissues, as the average enzyme activity was >13% of normal in somatic organs and 2% of normal in brain. Low expression markedly reduced histopathological evidence of lysosomal storage in liver, spleen, kidney, small intestine, neurons, and glial cells. High expression appeared to be more effective than low expression at reducing lysosomal storage in aorta, heart valves, thymus, bronchial epithelium, cornea, and retinal pigmented epithelium. Future experiments will determine if greater pathological improvements will consistently be observed in retrovirus-treated MPS VII mice with higher serum GUSB activity relative to animals with lower activity and if these result in clinical benefits.
Xu
Lingfei
L
Department of Internal Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA.
Mango
Robert L
RL
Sands
Mark S
MS
Haskins
Mark E
ME
Ellinwood
N Matthew
NM
Ponder
Katherine Parker
KP
D000818:Animals; D000831:Animals, Newborn; D001011:Aorta / Q000201:enzymology / Q000473:pathology; D001921:Brain / Q000201:enzymology / Q000473:pathology; D004285:Dogs; D005123:Eye / Q000201:enzymology / Q000473:pathology; D015316:Genetic Therapy; D005822:Genetic Vectors; D005966:Glucuronidase / Q000097:blood / Q000235:genetics* / Q000378:metabolism / Q000627:therapeutic use*; D006025:Glycosaminoglycans / Q000378:metabolism; D007421:Intestine, Small / Q000201:enzymology / Q000473:pathology; D008099:Liver / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D008168:Lung / Q000201:enzymology / Q000473:pathology; D051379:Mice; D016538:Mucopolysaccharidosis VII / Q000235:genetics / Q000473:pathology* / Q000628:therapy*; D009206:Myocardium / Q000201:enzymology / Q000473:pathology; D009928:Organ Specificity; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D013154:Spleen / Q000201:enzymology / Q000473:pathology; D013950:Thymus Gland / Q000201:enzymology / Q000473:pathology; D014161:Transduction, Genetic
D006025:Glycosaminoglycans; D012333:RNA, Messenger; D005966:Glucuronidase