Treatment of lysosomal storage disease in MPS VII mice using a recombinant adeno-associated virus.
Mucopolysaccharidosis type VII (MPS VII) is a lysosomal storage disease caused by a genetic deficiency of beta-glucuronidase (GUS). We used a recombinant adeno-associated virus vector (AAV-GUS) to deliver GUS cDNA to MPS VII mice. The route of vector administration had a dramatic effect on the extent and distribution of GUS activity. Intramuscular injection of AAV-GUS resulted in high, localized production of GUS, while intravenous administration produced low GUS activity in several tissues. This latter treatment of MPS VII mice reduced glycosaminoglycan levels in the liver to normal and reduced storage granules dramatically. We show that a single administration of AAV-GUS can provide sustained expression of GUS in a variety of cell types and is sufficient to reverse the disease phenotype at least in the liver. (+info)
Neonatal gene transfer leads to widespread correction of pathology in a murine model of lysosomal storage disease.
For many inborn errors of metabolism, early treatment is critical to prevent long-term developmental sequelae. We have used a gene-therapy approach to demonstrate this concept in a murine model of mucopolysaccharidosis type VII (MPS VII). Newborn MPS VII mice received a single intravenous injection with 5.4 x 10(6) infectious units of recombinant adeno-associated virus encoding the human beta-glucuronidase (GUSB) cDNA. Therapeutic levels of GUSB expression were achieved by 1 week of age in liver, heart, lung, spleen, kidney, brain, and retina. GUSB expression persisted in most organs for the 16-week duration of the study at levels sufficient to either reduce or prevent completely lysosomal storage. Of particular significance, neurons, microglia, and meninges of the central nervous system were virtually cleared of disease. In addition, neonatal treatment of MPS VII mice provided access to the central nervous system via an intravenous route, avoiding a more invasive procedure later in life. These data suggest that gene transfer mediated by adeno-associated virus can achieve therapeutically relevant levels of enzyme very early in life and that the rapid growth and differentiation of tissues does not limit long-term expression. (+info)
Systemic and central nervous system correction of lysosomal storage in mucopolysaccharidosis type VII mice.
Mucopolysaccharidosis (MPS) type VII patients lack functional beta-glucuronidase, leading to systemic and central nervous system dysfunction. In this study we tested whether recombinant adenovirus that encodes beta-glucuronidase (Adbetagluc), delivered intravenously and into the brain parenchyma of MPS type VII mice, could provide long-term transgene expression and correction of lysosomal distension. We also tested whether systemic treatment with the immunosuppressive anti-CD40 ligand antibody, MR-1, affected transgene expression. We found substantial plasma beta-glucuronidase activity for over 9 weeks after gene transfer in the MR-1- treated group, with subsequent decline in activity corresponding to a delayed anti-beta-glucuronidase antibody response. At 16 weeks, near wild-type amounts of beta-glucuronidase activity and striking reduction of lysosomal pathology were detected in livers from mice that had received either MR-1 cotreatment or control antibody. In the lung and kidney, beta-glucuronidase activity was markedly higher for the MR-1-treated group. beta-Glucuronidase activity in the brain persisted independently of MR-1 treatment. Activity was intense in the injected hemisphere and was also evident in the noninjected cortex and striatum, with dramatic improvements in storage deposits in areas of both hemispheres. These results indicate that prolonged enzyme expression from transgenes delivered to deficient liver and brain can mediate pervasive correction and illustrate the potential for gene therapy of MPS and other lysosomal storage diseases. (+info)
Behavior and therapeutic efficacy of beta-glucuronidase-positive mononuclear phagocytes in a murine model of mucopolysaccharidosis type VII.
Bone marrow transplantation (BMT) is relatively effective for the treatment of lysosomal storage diseases. To better understand the contribution of specific hematopoietic lineages to the efficacy of BMT, we transplanted beta-glucuronidase-positive mononuclear phagocytes derived from either the peritoneum or from bone marrow in vitro into syngeneic recipients with mucopolysaccharidosis type VII (MPS VII). Cell surface marking studies indicate that the bone marrow-derived cells are less mature than the peritoneal macrophages. However, both cell types retain the ability to home to tissues rich in cells of the reticuloendothelial system after intravenous injection into MPS VII mice. The half-life of both types of donor macrophages is approximately 7 days, and some cells persist for at least 30 days. In several tissues, therapeutic levels of beta-glucuronidase are present, and histopathologic analysis demonstrates that lysosomal storage is dramatically reduced in the liver and spleen. Macrophages intravenously injected into newborn MPS VII mice localize to the same tissues as adult mice but are also observed in the meninges and parenchyma of the brain. These data suggest that macrophages play a significant role in the therapeutic efficacy of BMT for lysosomal storage diseases and may have implications for treatments such as gene therapy. (+info)
Reduction of lysosomal storage in murine mucopolysaccharidosis type VII by transplantation of normal and genetically modified macrophages.
This study examined the ability of macrophages to serve as target cells of gene therapy for mucopolysaccharidosis (MPS) type VII using a murine model. Bone marrow cells were harvested from syngeneic normal mice and differentiated to macrophages. These cells were given to nonmyeloablated MPS VII mice. After transplantation, donor cells populated the liver and spleen. The pathologic improvement at day 38 after transplantation was significant and glycosaminoglycan storage was reduced. To develop gene therapy using this system, a retroviral vector expressing human beta-glucuronidase (HBG) was used to infect macrophages cultivated from MPS VII mice and given to nonmyeloablated MPS VII mice. At 38 days after transplantation, HBG-positive cells were still observed histochemically and pathologic improvement was significant. These observations suggest that macrophage transplantation is a promising method for treatment of murine MPS VII without myeloablation, and macrophages may be good target cells for ex vivo gene therapy for MPS VII. (+info)
Effects of bone marrow transplantation on the cardiovascular abnormalities in canine mucopolysaccharidosis VII.
The genetic mucopolysaccharidoses (MPS) are a family of lysosomal storage diseases resulting from defective catabolism of glycosaminoglycans (GAGs). Echocardiographic abnormalities in dogs with MPS type VII (Sly syndrome, beta-glucuronidase deficiency) included mitral valve thickening and insufficiency, large aortic dimensions in both the long and short axes, and thickened aortic valves. Grossly, at post mortem examination, there was nodular thickening of the mitral valve, a prominent ductus diverticulum, and a dilated aorta with thickened walls. Histologically, cytoplasmic vacuolation was seen in cells of the mitral valves, coronary arteries, and aorta. By electron microscopy, the cells of the mitral valve were packed with electron-lucent cytoplasmic vacuoles. The mean residual activity of beta-glucuronidase in the aorta and myocardium was <1% of normal, the mean hexosaminidase A activity >2. 5 times normal, and the mean GAG concentrations more than twice normal. In three MPS VII dogs that received heterologous BMT at 6 weeks of age, the echocardiographic abnormalities were improved, and the histopathologic and ultrastructural pathology was reduced. In the aorta and myocardium, the mean beta-glucuronidase activity of the BMT group was 4.5% and 11% of normal, respectively, and the hexosaminidase A activity and GAG concentrations were normalized. Bone Marrow Transplantation (2000) 25, 1289-1297. (+info)
Significantly increased expression of beta-glucuronidase in the central nervous system of mucopolysaccharidosis type VII mice from the latency-associated transcript promoter in a nonpathogenic herpes simplex virus type 1 vector.
Herpes simplex virus (HSV) has the ability to establish life-long latent infections in postmitotic neurons and to remain transcriptionally active, continuously expressing latency-associated transcripts (LAT) while producing minimal disease. These properties have made HSV an excellent candidate for neuronal gene transfer. Previously, we have shown that in mucopolysaccharidosis type VII mice (MPS VII, beta-glucuronidase deficiency) the LAT promoter is capable of expressing beta-glucuronidase (GUSB) in the trigeminal ganglion and the brainstem after latency is established. However, the number of neurons expressing GUSB is much lower than the number expressing 2-kb LAT following a wild-type virus infection. In this study, we have evaluated the effect of the position of the coding sequence relative to the LAT promoter on beta-glucuronidase gene expression in the central nervous system (CNS). Non-neurovirulent (ICP-34.5-deleted HSV-1) vectors were used, allowing direct intracranial injection. Significantly more GUSB activity was detected in brains of MPS VII mice inoculated with a recombinant virus (HSV-LAT-GUSB-JS) in which the GUSB cDNA was inserted near the LAT promoter, compared to viruses where it was inserted farther downstream in either the LAT exon 1 or overlapping exon 1 and the 2-kb LAT intron. This vector produced more than 100 times the number of positive cells than the other constructs. During acute infection, the distribution of viral replication differed from the distribution of GUSB enzyme expression. Viral antigen was predominately present in cells around the site of injection in the caudate putamen and in ependymal cells lining the ventricles. In contrast, GUSB expression was present mainly in cells of the thalamus and hypothalamus, which did not exhibit viral antigen, suggesting that GUSB enzyme activity was expressed from latently but not acutely infected neuronal cells. This vector design should be useful for high-level expression of various genes in the CNS. (+info)
Long-term and significant correction of brain lesions in adult mucopolysaccharidosis type VII mice using recombinant AAV vectors.
Most lysosomal storage diseases, including mucopolysaccharidosis, affect the central nervous system (CNS). They often induce severe and progressive mental retardation. Replacement therapy by purified enzyme infusions is a promising approach for the treatment of peripheral organs but without effect on CNS pathology because the enzyme cannot cross the blood-brain barrier. Intracranial injection of recombinant adeno-associated virus (AAV) vectors offers an alternative for sustained local enzyme delivery from genetically engineered cells. We stereotactically injected an AAV vector containing the human beta-glucuronidase cDNA into the striatum of adult mice severely affected by mucopolysaccharidosis type VII at the time of treatment. Six weeks later, beta-glucuronidase activity in the injected hemisphere was comparable to that of heterozygous mice, which have a normal phenotype. Areas staining positive for enzyme activity enlarged with time, representing more than 10% of the hemisphere volume by 16 weeks. A complete reversion of lysosomal storage lesions was evident in these areas, as well as in most neurons located in surrounding negative areas and in the noninjected hemisphere. Thus, a single intracerebral injection of AAV vectors could achieve a broad and sustained lysosomal enzyme delivery, allowing for stable reversion of storage lesions in a significant fraction of the adult brain. (+info)