Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.2.1.31 (beta-glucuronidase)
7,680 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mutations in the acid beta-glucuronidase gene lead to systemic accumulation of undegraded glycosaminoglycans in lysosomes and ultimately to clinical manifestations of mucopolysaccharidosis VII (Sly disease). Gene transfer by retrovirus vectors into murine mucopolysaccharidosis VII hematopoietic stem cells or fibroblasts ameliorates glycosaminoglycan accumulation in some affected tissues. The efficacy of gene therapy for mucopolysaccharidosis VII depends on the levels of beta-glucuronidase secreted by gene-corrected cells; therefore, enrichment of transduced cells expressing high levels of enzyme prior to transplantation is desirable. We describe the development of a fluorescence-activated cell sorter-based assay for the quantitative analysis of beta-glucuronidase activity in viable cells. Murine mucopolysaccharidosis VII cells transduced with a beta-glucuronidase retroviral vector can be isolated by cell sorting on the basis of beta-glucuronidase activity and cultured for further use. In vitro analysis revealed that sorted cells have elevated levels of beta-glucuronidase activity and secrete higher levels of cross-correcting enzyme than the population from which they were sorted. Transduced fibroblasts stably expressing beta-glucuronidase after subcutaneous passage in the mucopolysaccharidosis VII mouse can be isolated by cell sorting and expanded ex vivo. A relatively high percentage of these cells maintain stable expression after secondary transplantation, yielding significantly higher levels of enzymatic activity than that generated in the primary transplant.
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PMID:Single cell analysis and selection of living retrovirus vector-corrected mucopolysaccharidosis VII cells using a fluorescence-activated cell sorting-based assay for mammalian beta-glucuronidase enzymatic activity. 987 99

Mucopolysaccharidosis type VII (MPS VII) is a lysosomal storage disease caused by a deficiency in beta-glucuronidase. The disease has been well-characterized in B6.C-H-2bml/ByBir-gus(mps/mps) mice, which have proven to be an excellent model for the study of treatment modalities of storage diseases. However, because of the progressive nature of the disease, the mice deteriorate rapidly, have a greatly decreased life span, and are infertile. To increase fitness, B6.C-H-2bml/ByBir-gus(mps/+) were interbred with normal C3H mice. This study compares clinical findings, fertility, longevity, and gross and microscopic findings in the original strain with those in the F2 generation of the interbred strain.
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PMID:Variant clinical course of mucopolysaccharidosis type VII in two groups of mice carrying the same mutation. 988 57

We have previously sequenced the complete coding region and the promoter region of the beta-glucuronidase gene of a patient with mild mucopolysaccharidosis type VII (MPS VII) and identified a nonsense mutation in the gene inherited from her mother. The mutation inherited from her father was not found. Here, we have extended the sequence analysis of the introns to cover all putative lariat branch points and putative intronic enhancers, although no nucleotide changes have been found in these regions. Careful analysis of mRNA structure by reverse transcription/polymerase chain reaction (RT-PCR) and direct sequencing has revealed the inclusion of a new exon derived from an antisense Alu-repeat in intron 8 and the skipping of exon 9 in a large proportion of the mRNA of our patient. A 2-bp deletion creating a strong 5'-splice site has subsequently been identified in the paternal gene of the patient (IVS8+0.6kbdelTC). With a sensitive RT-PCR assay, we demonstrate that both the inclusion of the Alu-cassette and the skipping of exon 9 are minor events in control samples and that mRNA with both alterations is only found in the IVS8+0.6kbdelTC carrier. The increased proportion of exon 9 skipping seems to be related to the premature termination of translation. This is the third report of a human disease mutation that creates a splice site and activates an antisense Alu-cassette; the question rises as to how these apparently strong cryptic exons are generally excluded from coding sequences.
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PMID:A mutation (IVS8+0.6kbdelTC) creating a new donor splice site activates a cryptic exon in an Alu-element in intron 8 of the human beta-glucuronidase gene. 992 4

Mucopolysaccharidosis type VII (MPS VII), or Sly syndrome, is an autosomal recessive lysosomal storage disorder resulting from the deficiency in the activity of the enzyme beta-glucuronidase (GUSB). To characterize the biochemical and molecular defect in GUSB-deficient MPS VII dogs, we have measured lysosomal enzyme activities, analyzed distribution of glycosaminoglycans (GAGs), and estimated the size and abundance of the GUSB gene product at the mRNA and protein level in normal, homozygous affected, and heterozygous carrier retinal pigment epithelium (RPE) samples. Compared to normal, only 2-5% and 40-60% of GUSB activity was detected in the affected and the carrier samples, respectively. The decrease in GUSB activity resulted in storage of GAGs predominantly heparan sulfate and chondroitin sulfate. A slight increase in storage of GAGs was also observed in the carrier sample. Northern blot analysis of affected and carrier RPE samples detected a 2.4 kb GUSB transcript similar in size and abundance to that of normal controls. In western blot analysis using anti-human GUSB antibody, three bands of size 78, 56, and 38 kDa were detected in normal samples, which were present at lower intensity in the carrier RPE samples and absent in the MPS VII-affected RPE samples. These results suggest that the mutant GUSB gene causes a posttranscriptional defect and produces an unstable protein.
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PMID:Biochemical basis of the beta-glucuronidase gene defect causing canine mucopolysaccharidosis VII. 998 17

For many metabolic diseases, early correction of the inherited deficiency is required to prevent long-term sequelae. We examined the ability of adeno-associated virus (AAV) to mediate efficient gene transfer during the neonatal period in mice with the lysosomal storage disease mucopolysaccharidosis type VII (MPS VII). Quadriceps of newborn MPS VII mice were injected with an AAV vector containing human beta-glucuronidase (GUSB) cDNA. High-level intramuscular GUSB expression was seen as early as 2 weeks of age, and persisted for at least 16 weeks with no reduction in activity. In addition, GUSB activity was detected in both liver and spleen at later time points. The level of GUSB activity resulted in a significant reduction in lysosomal storage in the liver and a minimal reduction in the spleen at 16 weeks. However, the temporal and spatial pattern of hepatic GUSB activity, coupled with the presence of GUSB cDNA in liver sections, suggests that hematogenous dissemination of virus at the time of injection led to gene transfer to hepatic cells. These results demonstrate that AAV vectors can successfully infect neonatal muscle and persist through the rapid growth phase following birth. However, GUSB secretion from an intramuscular source is inefficient, limiting the therapeutic efficacy of this approach.
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PMID:Neonatal intramuscular injection with recombinant adeno-associated virus results in prolonged beta-glucuronidase expression in situ and correction of liver pathology in mucopolysaccharidosis type VII mice. 1002 33

Mice with mucopolysaccharidosis type VII (MPS VII) are devoid of beta-glucuronidase and accumulate glycosaminoglycans in lysosomes resulting in bone dysplasia, learning disabilities, and decreased mobility. MPS VII males do not breed and, while MPS VII females occasionally mate with heterozygous males, they do not maintain their young postnatally. Heterozygous matings produce less than 25% MPS VII offspring, but until now it was unclear whether this results from prenatal or postnatal losses. The administration of recombinant beta-glucuronidase from birth significantly reduces glycosaminoglycan storage in most tissues, increases life span, and improves the animal's cognitive ability and mobility. To determine whether reproductive failure is corrected by such therapy, male and female MPS VII mice were injected with enzyme at weekly intervals from birth to 5 wk of age (6xinj). Enzyme-replaced MPS VII mice bred when mated together. The 6xinj MPS VII males mated repeatedly until they were killed 135 d postinjection. All mated 6xinj MPS VII females gave birth to two litters, but maintained few of their young. Selective loss of MPS VII offspring was observed in matings between heterozygotes. Analysis of 379 preterm fetuses from heterozygous matings showed a frequency of 24.6% MPS VII pups, indicating that the decreased number of MPS VII pups produced by mating heterozygotes results from postnatal losses. The ovaries of young adult MPS VII mice have follicles and corpora lutea, and the testes generate sperm. Results suggest that the reproductive failure in MPS VII mice is related to impaired mobility and/or impaired cognitive function, and enzyme replacement restores mating capacity.
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PMID:Enzyme replacement therapy improves reproductive performance in mucopolysaccharidosis type VII mice but does not prevent postnatal losses. 1002 87

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.
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PMID:Treatment of lysosomal storage disease in MPS VII mice using a recombinant adeno-associated virus. 1002 43

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.
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PMID:Neonatal gene transfer leads to widespread correction of pathology in a murine model of lysosomal storage disease. 1005 35

A family of domestic cats was found that exhibited clinical and biochemical abnormalities consistent with mucopolysaccharidosis VII, an autosomal recessive lysosomal storage disorder caused by beta-glucuronidase deficiency. beta-Glucuronidase activity was undetectable in affected cat fibroblasts and restored by retroviral gene transfer of rat beta-glucuronidase cDNA. beta-Glucuronidase mRNA was normal in affected cat testis by Northern blot analysis. Normal feline beta-glucuronidase cDNA was cloned and characterized, and amplified from affected cat fibroblasts by reverse transcription coupled polymerase chain reaction. There was a G-to-A transition in the affected cat cDNA that predicted an E351K substitution, destroyed a BssSI site, and eliminated GUSB enzymatic activity in expression studies. Multiple species comparison and the crystal structure of human beta-glucuronidase indicated that E351 is a highly conserved residue most likely essential in maintenance of the enzyme's conformation. BssSI digestion of polymerase chain reaction products amplified from genomic DNA indicated that affected cats were homozygous and cats with half-normal beta-glucuronidase activity were heterozygous for the missense mutation. Carriers identified in this manner produced affected kittens in prospective breedings, and a feline MPS VII breeding colony has been established.
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PMID:Molecular basis of feline beta-glucuronidase deficiency: an animal model of mucopolysaccharidosis VII. 1036 43

We have previously shown that mucopolysaccharidosis type VII (MPS VII) mice receiving six weekly injections of recombinant beta-glucuronidase from birth had improved cognitive ability and reduced central nervous system lysosomal storage. However, a single beta-glucuronidase injection at 5 wk of age did not correct neuronal storage. We define the age at which central nervous system storage in MPS VII mice becomes resistant to beta-glucuronidase therapy and determine the effect of enzyme on other tissues by comparing the histology of mice begun on therapy at various times after birth. MPS VII mice received injections on the day of birth and then weekly for 5 wk with 16,000U/g beta-glucuronidase had reduced lysosomal storage in brain. The same therapy begun on d 14 of life or thereafter failed to correct neuronal storage, even when treatment was continued for six doses. Glial responsiveness or accessibility to enzyme also depended on early treatment. In contrast, leptomeningeal, osteoblast, and retinal pigment epithelial storage reduction depended on enzyme dose rather than age at initiation of therapy. Fixed tissue macrophage storage was reduced in all treated MPS VII mice, even those receiving a single dose. These observations indicate that fixed tissue macrophages in MPS VII mice remain sensitive to enzyme replacement therapy well into adulthood although neurons are responsive or accessible to enzyme therapy early in life. Because early initiation of enzyme replacement is important to achieve a central nervous system response, these studies emphasize the importance of newborn screening for lysosomal storage diseases so that early treatment can maximize the likelihood of a favorable therapeutic response.
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PMID:Enzyme replacement in murine mucopolysaccharidosis type VII: neuronal and glial response to beta-glucuronidase requires early initiation of enzyme replacement therapy. 1036 75


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