Thioredoxin is involved in endothelial cell extracellular transglutaminase 2 activation mediated by celiac disease patient IgA

Nadalutti, Cristina A., Korponay-Szabo, Ilma R., Kaukinen, Katri, Wang, Zhuo, Griffin, Martin, Mäki, Markku and Lindfors, Katri (2013). Thioredoxin is involved in endothelial cell extracellular transglutaminase 2 activation mediated by celiac disease patient IgA. PLoS ONE, 8 (10),

Abstract

Purpose: To investigate the role of thioredoxin (TRX), a novel regulator of extracellular transglutaminase 2 (TG2), in celiac patients IgA (CD IgA) mediated TG2 enzymatic activation. Methods: TG2 enzymatic activity was evaluated in endothelial cells (HUVECs) under different experimental conditions by ELISA and Western blotting. Extracellular TG2 expression was studied by ELISA and immunofluorescence. TRX was analysed by Western blotting and ELISA. Serum immunoglobulins class A from healthy subjects (H IgA) were used as controls. Extracellular TG2 enzymatic activity was inhibited by R281. PX12, a TRX inhibitor, was also employed in the present study. Results: We have found that in HUVECs CD IgA is able to induce the activation of extracellular TG2 in a dose-dependent manner. Particularly, we noted that the extracellular modulation of TG2 activity mediated by CD IgA occurred only under reducing conditions, also needed to maintain antibody binding. Furthermore, CD IgA-treated HUVECs were characterized by a slightly augmented TG2 surface expression which was independent from extracellular TG2 activation. We also observed that HUVECs cultured in the presence of CD IgA evinced decreased TRX surface expression, coupled with increased secretion of the protein into the culture medium. Intriguingly, inhibition of TRX after CD IgA treatment was able to overcome most of the CD IgA-mediated effects including the TG2 extracellular transamidase activity. Conclusions: Altogether our findings suggest that in endothelial cells CD IgA mediate the constitutive activation of extracellular TG2 by a mechanism involving the redox sensor protein TRX.

Publication DOI: https://doi.org/10.1371/journal.pone.0077277
Divisions: Life & Health Sciences > Biosciences
Life & Health Sciences
Aston University (General)
Additional Information: © 2013 Nadalutti et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
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Related URLs: http://www.scopus.com/inward/record.url?scp=84885092656&partnerID=8YFLogxK (Scopus URL)
Published Date: 2013-10-09
Authors: Nadalutti, Cristina A.
Korponay-Szabo, Ilma R.
Kaukinen, Katri
Wang, Zhuo
Griffin, Martin
Mäki, Markku
Lindfors, Katri

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License: Creative Commons Attribution


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