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)

The causation, structural origin, and mechanism of formation of spongiform lesions in transmissible encephalopathies are unknown. We have used immunogold electron microscopy to locate ubiquitin conjugates, hsp 70, and beta-glucuronidase (markers of the lysosomal compartment) and prion protein (PrP) in both control and scrapie-infected mouse brain. In scrapie-infected brain, lysosomes and lysosome-related structures (multivesicular and tubulovesicular dense bodies) are present in abnormally high numbers in neuronal cell processes. These structures contain PrP, together with the lysosomal markers ubiquitin conjugates, hsp 70, and beta-glucuronidase, which could also be identified spilling from tubulovesicular dense bodies into areas of early rarefaction in neuronal processes; we suggest that these areas of rarefaction are the precursor lesions of spongiform change. We advance the hypothesis that spongiform change is brought about by cytoskeletal disruption in neuronal processes caused by liberation of hydrolytic enzymes from lysosomes overloaded with the abnormal isoform of PrP (PrPsc). We suggest that the lysosomal system is probably acting as the bioreactor for processing of normal PrP to the abnormal isoform. The continuous production of increasing quantities of abnormal PrPsc in lysosome-related bodies will eventually cause disruption of the lysosomal membrane with destruction of the neuronal cytoskeleton and the initiation of vacuolation. Later, death of the cell will be associated with release of the PrPsc isoform into the extracellular environment. Repeated rounds of phagocytosis, lysosomal biogenesis of PrPsc, lysosomal membrane rupture, hydrolytic enzyme release, and neuronal lysis will lead to an exponential increase in cell damage and cell death.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Lysosomes as key organelles in the pathogenesis of prion encephalopathies. 135 30

The effect of scrapie prion protein (PrP) either in the native or in the denatured form was studied on in vitro responses of human neutrophils. Incubation of neutrophils with native PrP caused an inhibition of their aggregation induced by cytochalasin B. Moreover, the denatured form was in itself a strong aggregation inducer. When evaluating the effect on generation of neutrophil superoxide anion (O2) we found that neutrophils released O2 in response to the denatured from only but the native form was ineffective. Similarly, neutrophil discharge of beta-glucuronidase which represents the azurophilic granule marker was stimulated in a dose-dependent form by the denatured PrP 27-30 whereas the native form was almost completely devoid of any activity. These results indicate that several aspects of neutrophil function can be altered by the native form of prion protein PrP 27-30. This might be responsible for the impaired phagocytic cell activity explaining, at least in part, the absence of any inflammatory reaction during scrapie infection.
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PMID:Inhibition of neutrophil functions by scrapie prion protein: description of some inhibitory properties. 198 77

Cumulative results are presented of histopathological and enzyme histochemical findings in sheep naturally or experimentally infected with scrapie compared with healthy controls or animals with other diseases. Two hundred and sixty-eight sheep were examined, including 210 cases of clinical or suspected scrapie. According to the nature and distribution of histopathological changes, especially neuropil vacuolation and neuronal vacuoles, scrapie-affected sheep were classified into groups. In particular, examination of medulla oblongata revealed a consistently different pattern of lesions between natural scrapie (type A) and experimental scrapie (type B). Cytoplasmic enzymic inclusions demonstrated by methods for beta-glucuronidase and for acid phosphatase were regularly found in neurones from scrapie sheep but not from control animals. They appeared to be more prevalent in type B than in type A scrapie and were demonstrable even in tissue affected by post-mortem autolysis. The distribution of enzymic inclusions ranged from Betz cells of cerebral cortex to grey matter of the lumbar region of spinal cord. The detection of enzymic inclusions is a useful diagnostic criterion and has been incorporated into histological diagnostic procedures for scrapie.
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PMID:Intraneuronal enzymic inclusions in the histological diagnosis of scrapie. 632 70

Several glycosidase activities were measured in frontal gray matter of 4 brains from subjects affected by Creutzfeldt-Jakob disease. The changes of N-acetyl-beta-glucosaminidase, N-acetyl-beta-galactosaminidase, beta-glucosidase, alpha-fucosidase and alpha-mannosidase were not statistically significant but significant increases of beta-glucuronidase and beta-galactosidase activities were found. These results are in accordance with several reports on brain glycosidases in scrapie and Semliki Forest virus-infected brain and could explain some changes in brain glycoconjugate content previously observed in human and experimental Creutzfeldt-Jakob disease.
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PMID:Brain glycosidases in Creutzfeldt-Jakob disease. 678 37

The prion encephalopathies are characterized by accumulation in the brain of the abnormal form PrPsc of a normal host gene product PrPc. The mechanism and site of formation of PrPsc from PrPc are currently unknown. In this study, ME7 scrapie-infected mouse brain was used to show, both biochemically and by double-labelled immunogold electron microscopy, that proteinase K-resistant PrPsc is enriched in subcellular structures which contain the cation-independent mannose 6-phosphate receptor, ubiquitin-protein conjugates, beta-glucuronidase, and cathepsin B, termed late endosome-like organelles. The glycosylinositol phospholipid membrane-anchored PrPc will enter such compartment for normal degradation and the organelles may therefore act as chambers for the conversion of PrPc into infectious PrPsc in this murine model of scrapie.
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PMID:The abnormal isoform of the prion protein accumulates in late-endosome-like organelles in scrapie-infected mouse brain. 756 56