Disease relevance of Neu1

• Competitive inhibition kinetics were observed when 1,2, and 3 were tested with the lysosomal sialidase (cultured fibroblasts) and the plasma membrane sialidase (adenovirus DNA-transformed, human embryonic kidney cells), giving a Ki of about 10 microM for both enzymes with all three compounds [1].
• This paper shows that most murine (C57BL/6) influenza A virus-specific memory cytotoxic T lymphocyte (CTL) clones tested in limiting dilution did not react with the influenza A virus surface glycoproteins, hemagglutinin (HA) and neuraminidase (NA) [2].
• Active, high-affinity, sodium-dependent uptake of gamma-aminobutyric acid and of the acidic amino acid D-aspartate was inhibited by pretreatment of synaptosomes with neuraminidase from Vibrio cholerae [3].
• Treatment of cultured Hodgkin disease (HD) cells with neuraminidase results in decreased reactivity of monoclonal antibody VIM-D5 with its antigen, the X hapten, a fucosyl-N-acetyllactosamine [4].
• Digestion with Clostridium perfringens or Vibrio cholerae neuraminidase did not equalize pI but instead decreased the size and increased the pI of both ARH and THC cell-CAM 105 [5].

High impact information on Neu1

• However, treatment of primary rat islet cells with neuraminidase exposed surface antigens and rendered the cells susceptible to complement-mediated lysis by antibody E5C2 [6].
• Chromatographic analysis showed that the bulk of the radioactivity released by T. cruzi neuraminidase was sialic acid [7].
• Galactose oxidase labeling demonstrated newly desialylated glycoproteins on the surface of myocardial cells treated with T. cruzi neuraminidase [7].
• We recently found that the infective trypomastigote form a T. cruzi exhibits neuraminidase activity and can desialylate mammalian erythrocytes [7].
• A neuraminidase from Trypanosoma cruzi removes sialic acid from the surface of mammalian myocardial and endothelial cells [7].

Chemical compound and disease context of Neu1

• After treatment of rats with radiolabeled N-[acyl-1-14C]D-mannosamine, radioactivity could be removed from serum glycoprotein fractions by incubation with neuraminidase from Clostridium perfringens or from Arthrobacter ureafaciens [8].
• The maximum percent histamine release is achieved in <10 s, and it can be markedly inhibited by pertussis toxin (100 ng/ml) and by pretreatment of mast cells with neuraminidase [9].
• Histamine was released in a nonlytic manner and the mast cell stimulation by both natural and synthetic factors was sensitive to pertussis toxin, neuraminidase, benzalkonium chloride, and to an excess of calcium [10].
• This effect was probably due to degradation by bacteria, as demonstrated in vitro with the production of lactosylceramide after treatment of the isolated acid glycolipids of sterile feces with neuraminidase from Clostridium perfringens [11].
• To investigate the role of sialic acid in the ependyma of the rat brain, we injected neuraminidase from Clostridium perfingens into the lateral ventricle of 86 adult rats that were sacrificed at various time intervals [12].

Biological context of Neu1

• Age-specific changes in glycosylation of rat intestinal lactase-phlorizin hydrolase were analyzed using enzyme immunoprecipitated from microvillus membranes of suckling, weaning, and adult rats, and carbohydrate moieties were examined by lectin affinity binding, metabolic labeling, and neuraminidase treatment [13].
• This proposed mechanism is indistinguishable from the autoinhibition phenomenon described for another galactophilic binding protein, the hepatic binding protein (HBP), which binds its own terminal galactosyl residues following neuraminidase treatment [4].
• A distinct population of neuraminidase-resistant WGA binding sites was also found in axons directly proximal to the transport block [14].
• To examine whether hepatic plasma membrane receptors for asialoglycoproteins are replaced or reutilized during endocytosis, receptors on the surface of isolated hepatocytes were uniquely labeled by neuraminidase treatment [15].
• Neuraminidase treatment sufficient to cause greater than 90% loss of insulin stimulatable lipogenesis had no effect on 125I-insulin binding, tyrosine kinase activity of partially purified insulin receptors, insulin receptor phosphorylation in intact cells, or insulin-induced receptor internalization [16].

Anatomical context of Neu1

• It is concluded that cerebellar granule cells differentiated in vitro possess one lysosomal sialidase and two plasma membrane sialidases, all of them active on ganglioside [17].
• In contrast, brain lysosomal sialidase was not significantly altered by ethanol treatment, even though the major proportion of the brain sialidase activity was localized in the lysosomes [18].
• However, specific bile acid binding is markedly decreased by low concentrations of proteolytic enzymes and is also decreased by the action of neuraminidase and phospholipases A and C. These results are consistent with the existence of a homogeneous bile acid receptor protein in liver surface membranes [19].
• Human breast sections, like those of the rat, showed fluorescent labeling at the apical region of the epithelial cells; this labeling increased if the tissue had prior treatment with neuraminidase [20].
• T. cruzi neuraminidase also removed sialic acid from adult human saphenous vein endothelial cells, as determined by both histochemical and metabolic labeling studies [7].

Associations of Neu1 with chemical compounds

• When isoelectric focusing electrophoresis was carried out over a narrow range of pH (5-7), each of the apolipoprotein E isoforms of affected members was observed as a doublet, even after reduction of dimers of the protein with 2-mercaptoethanol and treatment with neuraminidase to minimize the content of sialylated forms of the protein [21].
• The glycoprotein nature of these species was investigated using endoglycosidase F (endo F) and neuraminidase treatment and wheat germ agglutinin-agarose chromatography [22].
• Experiments to block adhesion by pretreatment of cells with either neuraminidase or mucin show that the sialic acids-rich moiety is on the nerve cells, while its receptor is on the muscle fibers [23].
• PCF binding at pH 1.8 at the nonmodified luminal cell surface is significantly diminished by neuraminidase treatment which, however, does not perceptibly reduce PCF binding at the higher pH levels [24].
• WGA binding is not removed by prior digestion with neuraminidase and succinyl-WGA also binds the proximal cilium, suggesting a predominance of N-acetylglucosamine containing glycoconjugates [25].

Physical interactions of Neu1

• Both the mature 250-kDa receptor and the neuraminidase-digested 245-kDa form specifically bound 125-I-IGF-II [26].
• Digestion of covalently linked [125I]human (h) GH-receptor complexes with neuraminidase or endoglycosidase F reduced the mass of the principal hormone receptor complex from about 130 kilodaltons (kDa) to 120 and 110 kDa, respectively, suggesting that about 20% of the mass of the GH receptor of rat adipocytes consists of N-linked sialocarbohydrates [27].
• Treatment of both enzymes with neuraminidase enhanced the binding of aminopeptidase to RCAI-Sepharose by 4-fold but did not alter the binding patterns of dipeptidyl peptidase IV [28].

Other interactions of Neu1

• Desialation of RBL cell surface glycoproteins by neuraminidase treatment eliminated IL-4 release [29].
• Treatment of AtT-20 cell membranes with neuraminidase from V. cholera was also able to greatly reduce the affinity of SRIF receptors for [125I]MK 678.(ABSTRACT TRUNCATED AT 400 WORDS)[30]
• Unlike NGF, the neuraminidase does not react with the apoptosis-causing pan-neurotrophin receptor p75NTR [31].
• As muscles develop, the extent of sialylation of muscle N-CAM decreases, and a 140-kD desialo form of N-CAM (generated by neuraminidase treatment) is replaced by a 125-kD form [32].
• Chemical analysis of such nuclei from neuraminidase-treated cells confirmed significant elevation of GM1 above control levels, along with virtual absence of markers for plasma membrane and Golgi apparatus [33].

Analytical, diagnostic and therapeutic context of Neu1

• 125I-AII binding to GBM was increased after treatment of these membranes with collagenase, slightly diminished with neuraminidase, and almost completely abolished with trypsin suggesting the proteic nature of the receptor [34].
• Such antibodies to tachyzoite proteins of < or = 14, 22, 26-28, 30, 46, 60, 70-80, and > 100 kD (eliminated by protease but not periodate or neuraminidase treatment) were demonstrated in whey from acutely infected subjects when Western blots were probed with their whey and antibodies to human secretory IgA or IgA or secretory piece [35].
• Peanut agglutinin, purified by affinity chromatography, agglutinates lymphocytes from mouse, rat, guinea pig, and man only after their treatment with neuraminidase [36].
• A 150-kDa C3b-binding protein was isolated from rat platelets, which had immunochemical and biochemical identity to plasma factor H. Immunofluorescence microscopy and flow cytometry demonstrated that factor H was present on the surface of rat and mouse platelets, which could be removed by treatment with neuraminidase [37].
• However, two-dimensional gel electrophoresis in combination with neuraminidase digestion demonstrated that sialylation was markedly inhibited by Tris [38].

References