Sialidases expression

X. Nan, I. Carubelli, and N. M. Stamatos, Sialidase expression in activated human T lymphocytes influences production of IFN-gamma, J. Leukoc. Biol, 81... 

The discovery of Zanamivir as a potent and selective inhibitor of influenza virus sialidase prompted several researchers to investigate the synthesis and structure-activity relationship studies of Neu5Ac2en-based compounds as potential sialidase inhibitors. Exploration of these SAR studies were undertaken to optimize inhibitory activity and to improve the physicochemical properties of the sialic acid-based influenza virus sialidase inhibitor. A few in vitro assays are commonly employed to measure the effectiveness of influenza virus sialidase inhibitors. The first involves a fluorometric assay that measures release of a synthetic fluorophore following its cleavage from Neu5Ac by sialidase. Dye-uptake assay, such as the Neutral Red uptake assay, measures the uptake of a vital stain, Neutral Red in cell culture. The process requires intact membranes and active metabolism in the cell, and is expressed as percent protective rate against virus infection. The plaque-reduction assay is used to measure sialidase inhibition indirectly in cell culture, and provides some measure of the inhibitor s effect on the viability of the influenza virus. In vitro and in vivo systems for analysis of inhibitors of influenza virus enzymes have been reviewed.71... 

M. G. Risso, G. B. Garbarino, E. Mocetti, O. Campetella, S. M. Gonzalez Cappa, C. A. Buscaglia, and M. S. Leguizamon, Differential expression of a virulence factor, the trans-sialidase, by the main Trypanosoma cruzi phylogenetic lineages, J. Infect. Dis., 189 (2004) 2250-2259. 

Our group has reported a novel multifunctional bacterial enzyme, Pasteurella multocida sialyltransferase (PmSTl). PmSTl is an easy to express extremely soluble, and highly active sialyltransferase. Routinely, about 100 mg of PmSTl can be purified from one liter E. coli cell culture. PmSTl has four different activities including a2,3-sialyltransferase (optimal activity at pH 7.5-9.0), a2,6-sialyltransferase (optimal activity at pH 4.5-7.0), a2,3-sialidase (optimal activity at pH 5.0-5.5), and trans-sialidase (optimal activity at pH 5.5-6.5) activities. Among them, a2,3-sialyltransferase activity is the major function of the PmSTl with a specific activity of 60 U/mg protein (24),... 

Among the most relevant and well-studied parasite glycotopes ate the sialic acid group of sugars and their derivatives. Expression of surface terminal sialic acid and its derivative is due to the interplay between several enzymes namely sialidases, sialyltransferases, O-acetyl transferase and O-acetyl esterase. Therefore, synthetic analogues design to inhibit their expression appears to be an attractive treatment protocol. 

The possibihty that the sialylation level of glycoproteins is cracial for tiie shift from apoptosis to malignant proliferation is an intriguing working hypofliesis, and opens new perspectives in therapeutieal approaches for ehronic myeloid leukemia based on the eytosolie sialidase NEU2 expression. 

In 2008, the involvement of sialidases in human myeloid eell differentiation and neutrophil adhesion to dendritie eells was reported. The expression of Lewis X (Le ... 

DC. In siuco Analysis of Sialidase Gene Expression Patterns... 

Although in silica analysis of large-scale gene expression data offers some interesting clues about the biological relevance of sialidases in different tissues and cell types, there remains of course the need of more specific and deeper studies, both at the RNA and at the protein level, to better define the role of these enzymes in health and disease. 

Overall, the studies in zebrafish suggest the presence of a complex regulation pattern for expression of the enzymes involved in sialoglycoconjugate synthesis and degradation. Study of the different members of the sialidase gene family in this model organism offers a novel and attractive field of glycobiology. In particular, the... 

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