The Journal of Neuroscience, April 15, 2003, 23(8):3302
Intravitreal Gene Therapy Reduces Lysosomal Storage in Specific
Areas of the CNS in Mucopolysaccharidosis VII Mice
Anne K.
Hennig1,
Beth
Levy4,
Judith Mosinger
Ogilvie2, 5,
Carole A.
Vogler4,
Nancy
Galvin4,
Steven
Bassnett2, and
Mark S.
Sands1, 3
1 Department of Internal Medicine, Division of Stem
Cell Biology, and Departments of 2 Ophthalmology and Visual
Sciences and 3 Genetics, Washington University School of
Medicine, St. Louis, Missouri 63110, 4 Department of
Pathology, St. Louis University School of Medicine, St. Louis, Missouri
63107, and 5 Fay and Carl Simons Center for the Biology of
Hearing and Deafness, Central Institute for the Deaf, St. Louis,
Missouri 63110
The mucopolysaccharidoses (MPSs) are lysosomal storage diseases
resulting from impaired catabolism of sulfated glycosaminoglycans. MPS
VII mice lack lysosomal
-glucuronidase (GUSB) activity, leading to
the accumulation of partially degraded chondroitin, dermatan, and
heparan sulfates in most tissues. Consequently, these mice develop most
of the symptoms exhibited by human MPS VII patients, including
progressive visual and cognitive deficits. To investigate the effects
of reducing lysosomal storage in nervous tissues, we injected
recombinant adeno-associated virus encoding GUSB directly into the
vitreous humor of young adult mice. Interestingly, GUSB activity was
subsequently detected in the brains of the recipients. At 8-12 weeks
after treatment, increased GUSB activity and reduced lysosomal
distension were found in regions of the thalamus and tectum that
received inputs from the injected eye. Lysosomal storage was also
reduced in adjacent nonvisual regions, including the hippocampus, as
well as in the visual cortex. The findings suggest that both diffusion
and trans-synaptic transfer contribute to the dissemination of enzyme
activity within the CNS. Intravitreal injection may thus provide a
means of delivering certain therapeutic gene products to specific areas
within the CNS.
Key words:
CNS; gene therapy; genetic diseases; inborn errors
of metabolism; axonal transport; lysosomal storage reduction
Copyright © 2003 Society for Neuroscience 0270-6474/03/2383302-06$05.00/0