Inhibition of transglutaminase 2 enzymatic activity ameliorates the anti-angiogenic effects of coeliac disease autoantibodies

Abstract

Objective. Earlier work has demonstrated that serum autoantibodies from coeliac patients targeted against transglutaminase 2 (TG2) inhibit in vitro angiogenesis. The aim of this study was to establish whether coeliac patient-derived monoclonal TG2-targeted antibodies produced by recombination technology exert similar anti-angiogenic effects to serum-derived coeliac autoantibodies. In addition, we studied whether the monoclonal patient autoantibodies modulate endothelial cell TG2 activity and whether such modulation is related to the anti-angiogenic effects. Material and methods. The influence of coeliac patient-derived monoclonal TG2-targeted antibodies on endothelial cell tubule formation was studied using a three-dimensional angiogenic cell culture model. Endothelial cell TG2 enzymatic activity was determined by means of a live-cell enzyme-linked immunosorbent assay. Results. Coeliac patient-derived monoclonal TG2-targeted antibodies produced by recombination technology inhibited endothelial tubule formation and enhanced the crosslinking activity of TG2. When this enzymatic activity was inhibited using site-directed irreversible TG2 inhibitors in the presence of autoantibodies, in vitro angiogenesis reverted to the control level. Conclusions. Since we found a significant negative correlation between endothelial cell angiogenesis and TG2 activity, we suggest that the anti-angiogenic effects of coeliac patient-derived TG2-targeted autoantibodies are exerted by enhanced enzymatic activity of TG2.

Key Words::

• Autoantibodies
• coeliac disease
• transglutaminase 2 activity

Acknowledgements

The authors thank Mr. Jorma Kulmala for technical assistance. The Coeliac Disease Study Group has been financially supported by the Research Council for Health, the Academy of Finland, the Juselius Foundation, the Paediatric Research Foundation, the Competitive Research Funding of the Pirkanmaa Hospital District, the Research Fund of the Finnish Coeliac Society, the Hungarian Scientific Research Fund (OTKA K61868) and the European Commission (contract number MRTN-CT-2006-036032).

Declaration of interest: The authors report no conflicts of interest for the content and writing of the paper.