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High glucose removes natural anti-α-galactoside and anti-β-glucoside antibody immune complexes adhering to surface O-glycoproteins of normal platelets and enhances platelet aggregation

Human natural anti-α-galactoside (anti-Gal) and anti-β-glucoside (ABG) antibodies were previously reported to recognize the serine- and threonine-rich peptide sequences (STPS) of albumin-associated O-glycoproteins (AOP1 and AOP2) as surrogate antigens, forming anti-Gal/ABG-AOP1/AOP2-albumin triplet...

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Autores principales: Karthi, Sreedevi, Sukumari-Ramesh, Sangeetha, Geetha, Mandagini, Appukuttan, Padinjaradath Sankunni
Formato: Online Artículo Texto
Lenguaje:English
Publicado: D.A. Spandidos 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8652397/
https://www.ncbi.nlm.nih.gov/pubmed/34934451
http://dx.doi.org/10.3892/etm.2021.11005
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author Karthi, Sreedevi
Sukumari-Ramesh, Sangeetha
Geetha, Mandagini
Appukuttan, Padinjaradath Sankunni
author_facet Karthi, Sreedevi
Sukumari-Ramesh, Sangeetha
Geetha, Mandagini
Appukuttan, Padinjaradath Sankunni
author_sort Karthi, Sreedevi
collection PubMed
description Human natural anti-α-galactoside (anti-Gal) and anti-β-glucoside (ABG) antibodies were previously reported to recognize the serine- and threonine-rich peptide sequences (STPS) of albumin-associated O-glycoproteins (AOP1 and AOP2) as surrogate antigens, forming anti-Gal/ABG-AOP1/AOP2-albumin triplet immune complexes in plasma. Since antibodies in these triplets still possessed unoccupied binding sites, the presence of triplets on human platelets that abound in surface O-glycoproteins was examined. Upon treatment with α-galactosides and β-glucosides, normal platelets freshly isolated from young healthy individuals released triplets identical with plasma triplets according to ELISA results. The resulting denuded platelets, unless pre-treated with fibrinogen or the O-glycan-binding lectin jacalin, recaptured these sugar-extracted triplets in the absence of antibody-specific sugars, suggesting that the triplet antibodies recognized the STPS of O-glycosylated receptors on platelets. Molecular weight of the dominant jacalin-binding subunit on triplet-free platelet membrane was 116 kDa, close to the ~120 kDa reported for the IIb subunit of the most abundant fibrinogen-binding platelet O-glycoprotein, GPIIb/IIIa. Denuded, but not native, platelets underwent slow spontaneous aggregation and rapid ADP-mediated GPIIb/IIIa-dependent aggregation according to spectrophotometric assay. Pre-treatment of denuded platelets with jacalin significantly reduced their ADP-mediated aggregation. Amyloid β (Aβ-42 monomer) was reported to bind triplet O-glycoproteins through their STPS but not to albumin or the antibodies. This peptide bound to the triplets on normal platelets and to surface membrane O-glycoproteins on denuded platelets, suggesting that the surface O-glycoproteins on the normal platelets were engaged and masked by the triplets. The ABG-specific sugar glucose denuded the platelets at concentrations typically reached in diabetic sera, since anti-Gal specific or ABG-specific sugar released the triplets of both the antibodies from the platelets. In conclusion, the present study offered rationale for the presence of anti-Gal/ABG-O-glycoprotein-albumin triplets on normal platelets, for the role of triplets in platelet physiology amidst circulating platelet-activating factors such as ADP, and for platelet vulnerability during diabetes.
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spelling pubmed-86523972021-12-20 High glucose removes natural anti-α-galactoside and anti-β-glucoside antibody immune complexes adhering to surface O-glycoproteins of normal platelets and enhances platelet aggregation Karthi, Sreedevi Sukumari-Ramesh, Sangeetha Geetha, Mandagini Appukuttan, Padinjaradath Sankunni Exp Ther Med Articles Human natural anti-α-galactoside (anti-Gal) and anti-β-glucoside (ABG) antibodies were previously reported to recognize the serine- and threonine-rich peptide sequences (STPS) of albumin-associated O-glycoproteins (AOP1 and AOP2) as surrogate antigens, forming anti-Gal/ABG-AOP1/AOP2-albumin triplet immune complexes in plasma. Since antibodies in these triplets still possessed unoccupied binding sites, the presence of triplets on human platelets that abound in surface O-glycoproteins was examined. Upon treatment with α-galactosides and β-glucosides, normal platelets freshly isolated from young healthy individuals released triplets identical with plasma triplets according to ELISA results. The resulting denuded platelets, unless pre-treated with fibrinogen or the O-glycan-binding lectin jacalin, recaptured these sugar-extracted triplets in the absence of antibody-specific sugars, suggesting that the triplet antibodies recognized the STPS of O-glycosylated receptors on platelets. Molecular weight of the dominant jacalin-binding subunit on triplet-free platelet membrane was 116 kDa, close to the ~120 kDa reported for the IIb subunit of the most abundant fibrinogen-binding platelet O-glycoprotein, GPIIb/IIIa. Denuded, but not native, platelets underwent slow spontaneous aggregation and rapid ADP-mediated GPIIb/IIIa-dependent aggregation according to spectrophotometric assay. Pre-treatment of denuded platelets with jacalin significantly reduced their ADP-mediated aggregation. Amyloid β (Aβ-42 monomer) was reported to bind triplet O-glycoproteins through their STPS but not to albumin or the antibodies. This peptide bound to the triplets on normal platelets and to surface membrane O-glycoproteins on denuded platelets, suggesting that the surface O-glycoproteins on the normal platelets were engaged and masked by the triplets. The ABG-specific sugar glucose denuded the platelets at concentrations typically reached in diabetic sera, since anti-Gal specific or ABG-specific sugar released the triplets of both the antibodies from the platelets. In conclusion, the present study offered rationale for the presence of anti-Gal/ABG-O-glycoprotein-albumin triplets on normal platelets, for the role of triplets in platelet physiology amidst circulating platelet-activating factors such as ADP, and for platelet vulnerability during diabetes. D.A. Spandidos 2022-01 2021-11-25 /pmc/articles/PMC8652397/ /pubmed/34934451 http://dx.doi.org/10.3892/etm.2021.11005 Text en Copyright: © Karthi et al. https://creativecommons.org/licenses/by-nc-nd/4.0/This is an open access article distributed under the terms of the Creative Commons Attribution-NonCommercial-NoDerivs License (https://creativecommons.org/licenses/by-nc-nd/4.0/) , which permits use and distribution in any medium, provided the original work is properly cited, the use is non-commercial and no modifications or adaptations are made.
spellingShingle Articles
Karthi, Sreedevi
Sukumari-Ramesh, Sangeetha
Geetha, Mandagini
Appukuttan, Padinjaradath Sankunni
High glucose removes natural anti-α-galactoside and anti-β-glucoside antibody immune complexes adhering to surface O-glycoproteins of normal platelets and enhances platelet aggregation
title High glucose removes natural anti-α-galactoside and anti-β-glucoside antibody immune complexes adhering to surface O-glycoproteins of normal platelets and enhances platelet aggregation
title_full High glucose removes natural anti-α-galactoside and anti-β-glucoside antibody immune complexes adhering to surface O-glycoproteins of normal platelets and enhances platelet aggregation
title_fullStr High glucose removes natural anti-α-galactoside and anti-β-glucoside antibody immune complexes adhering to surface O-glycoproteins of normal platelets and enhances platelet aggregation
title_full_unstemmed High glucose removes natural anti-α-galactoside and anti-β-glucoside antibody immune complexes adhering to surface O-glycoproteins of normal platelets and enhances platelet aggregation
title_short High glucose removes natural anti-α-galactoside and anti-β-glucoside antibody immune complexes adhering to surface O-glycoproteins of normal platelets and enhances platelet aggregation
title_sort high glucose removes natural anti-α-galactoside and anti-β-glucoside antibody immune complexes adhering to surface o-glycoproteins of normal platelets and enhances platelet aggregation
topic Articles
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8652397/
https://www.ncbi.nlm.nih.gov/pubmed/34934451
http://dx.doi.org/10.3892/etm.2021.11005
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