Glycosidases—Properties and Application to the Study of Complex Carbohydrates and Cell Surfaces

Flowers, Harold M.; Sharon, Nathan

doi:10.1002/9780470122938.ch2

Cited by 14 publications

(4 citation statements)

References 298 publications

(71 reference statements)

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“…The engagement of mixed glioma-microglia monolayer cultures should be the next observation of the involvement of Siglec checkpoint in cellular direct interactions. Moreover, previous studies have shown that the structure of membrane glycoconjugates is highly variable and depends on the phase of cell division [89,90]. The estimation and comparison of sialylation and related changes in Siglecs recognition may be interesting in the range of different cell cycle phases of tested glioma cells.…”

Section: Discussionmentioning

confidence: 99%

The Paired Siglecs in Brain Tumours Therapy: The Immunomodulatory Effect of Dexamethasone and Temozolomide in Human Glioma In Vitro Model

Wielgat

Wawrusiewicz‐Kurylonek

Czarnomysy

et al. 2021

IJMS

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The paired sialic acid-binding immunoglobulin like lectins (Siglecs) are characterized by similar cellular distribution and ligand recognition but opposing signalling functions attributed to different intracellular sequences. Since sialic acid—Siglec axis are known to control immune homeostasis, the imbalance between activatory and inhibitory mechanisms of glycan-dependent immune control is considered to promote pathology. The role of sialylation in cancer is described, however, its importance in immune regulation in gliomas is not fully understood. The experimental and clinical observation suggest that dexamethasone (Dex) and temozolomide (TMZ), used in the glioma management, alter the immunity within the tumour microenvironment. Using glioma-microglia/monocytes transwell co-cultures, we investigated modulatory action of Dex/TMZ on paired Siglecs. Based on real-time PCR and flow cytometry, we found changes in SIGLEC genes and their products. These effects were accompanied by altered cytokine profile and immune cells phenotype switching measured by arginases expression. Additionally, the exposure to Dex or TMZ increased the binding of inhibitory Siglec-5 and Siglec-11 fusion proteins to glioma cells. Our study suggests that the therapy-induced modulation of the interplay between sialoglycans and paired Siglecs, dependently on patient’s phenotype, is of particular signification in the immune surveillance in the glioma management and may be useful in glioma patient’s therapy plan verification.

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Section: Discussionmentioning

confidence: 99%

The Paired Siglecs in Brain Tumours Therapy: The Immunomodulatory Effect of Dexamethasone and Temozolomide in Human Glioma In Vitro Model

Wielgat

Wawrusiewicz‐Kurylonek

Czarnomysy

et al. 2021

IJMS

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“…Moreover, the most effective Dex concentration decreasing Olig2 expression—10 µM—corresponded to that revealed as the most arresting G 0 /G 1 phase in GL261 and SMA560 cells. It has been shown previously that the total content of several monosaccharides is at minimum, whereas the degree of sialylation is at maximum just before and during cell division glycotopes [ 38 ]. It is in agreement with our observation that reduced sialylation correspond to Dex-induced growth inhibition in immunogenic SMA560 cells.…”

Section: Discussionmentioning

confidence: 99%

Sialic acids as cellular markers of immunomodulatory action of dexamethasone on glioma cells of different immunogenicity

et al. 2018

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Glucocorticosteroids, including dexamethasone (Dex), are commonly used to control tumor-induced edema in the brain tumor patients. There are increasing evidences that immunosuppressive action of Dex interferes with immune surveillance resulting in lower patients overall survival; however, the mechanisms underlying these actions remain unclear. Changes in the expression of sialic acids are critical features of many cancers that reduce their immunogenicity and increase viability. Sialoglycans can be recognized by CD33-related Siglecs that negatively regulate the immune response and thereby impair immune surveillance. In this study, we analysed the effect of Dex on cell surface sialylation pattern and recognition of these structures by Siglec-F receptor in poorly immunogenic GL261 and immunogenic SMA560 glioma cells. Relative amount of α2.3-, α2.6- and α2.8-linked sialic acids were detected by Western blot with MAA ( Maackia amurensis) and SNA ( Sambucus nigra ) lectins, and flow cytometry using monoclonal antibody anti-PSA-NCAM. In response to Dex, α2.8 sialylation in both, GL261 and SMA560 was increased, whereas the level of α2.3-linked sialic acids remained unchanged. Moreover, we found the opposite effects of Dex on α2.6 sialylation in poorly immunogenic and immunogenic glioma cells. Furthermore, changes in sialylation pattern were accompanied by dose-dependent effects of Dex on Siglec-F binding to glioma cell membranes as well as decreased α-neuraminidase activity. These results suggest that glucocorticosteroid-induced alterations in cell surface sialylation and Siglecs recognition may dampen anti-tumor immunity, and participate in glioma-promoting process by immune cells. Our study gives new view on corticosteroid therapy in glioma patients.

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“…The supernatant from centrifugation of the homogenate at 5000 rpm for 15 min was utilized as an enzyme source (ES). Levels of the hydrolytic and detoxification enzymes amylase [33], protease [34], invertase [35], lipase [36], acid phosphatase [37], glycosidase [38], trehalase [39], phospholipase A 2 [40], esterase [41], and lactate dehydrogenase [42] were quantified using standard procedures as described below.…”

Section: Enzyme Bioassaymentioning

confidence: 99%

Insecticidal Mechanism of Botanical Crude Extracts and Their Silver Nanoliquids on Phenacoccus solenopsis

Madasamy

Sahayaraj

Sayed

et al. 2023

Toxics

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In recent years, intensive studies have been carried out on the management of agricultural insect pests using botanical insecticides in order to decrease the associated environmental hazards. Many studies have tested and characterized the toxic action of plant extracts. Four plant extracts (Justicia adhatoda, Ipomea carnea, Pongamia glabra, and Annona squamosa) containing silver nanoparticles (AgNPs) were studied for their effects on Phenacoccus solenopsis Tinsley (Hemiptera: Pseudococcidae) using the leaf dip method. The effects were estimated based on assays of hydrolytic enzyme (amylase, protease, lipase, acid phosphatase, glycosidase, trehalase, phospholipase A2, and invertase) and detoxification enzyme (esterase and lactate dehydrogenase) levels; macromolecular content (total body protein, carbohydrate, and lipid); and protein profile. The results show that the total body of P. solenopsis contains trypsin, pepsin, invertase, lipase, and amylase, whereas J. adathoda and I. carnea aqueous extracts considerably decreased the protease and phospholipase A2 levels, and A. squamosa aqueous extract dramatically increased the trehalase level in a dose-dependent manner. The enzyme levels were dramatically decreased by P. glabura-AgNPs (invertase, protease, trehalase, lipase, and phospholipase A2); I. carnea-AgNPs (invertase, lipase, and phospholipase A2); A. squamosa-AgNPs (protease, phospholipase A2); and J. adathoda-AgNPs (protease, lipase, and acid phosphatase). Plant extracts and their AgNPs significantly reduced P. solenopsis esterase and lactate dehydrogenase levels in a dose-dependent manner. At higher concentrations (10%), all of the investigated plants and their AgNPs consistently decreased the total body carbohydrate, protein, and fat levels. It is clear that the plant extracts, either crude or together with AgNPs, may result in the insects having inadequate nutritional capacity, which will impact on all critical actions of the affected hydrolytic and detoxication enzymes.

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Glycosidases—Properties and Application to the Study of Complex Carbohydrates and Cell Surfaces

Cited by 14 publications

References 298 publications

The Paired Siglecs in Brain Tumours Therapy: The Immunomodulatory Effect of Dexamethasone and Temozolomide in Human Glioma In Vitro Model

The Paired Siglecs in Brain Tumours Therapy: The Immunomodulatory Effect of Dexamethasone and Temozolomide in Human Glioma In Vitro Model

Sialic acids as cellular markers of immunomodulatory action of dexamethasone on glioma cells of different immunogenicity

Insecticidal Mechanism of Botanical Crude Extracts and Their Silver Nanoliquids on Phenacoccus solenopsis

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