Abstract
The importance of transglutaminase 2 (TG2) in angiogenesis has been highlighted in recent studies, but other roles of this multi-functional enzyme in endothelial cell (EC) function still remains to be fully elucidated. We previously showed that the extracellular TG2 is involved in maintaining tubule formation in ECs by a mechanism involving matrix-bound vascular endothelial growth factor (VEGF) signalling. Here, by using the ECs and fibroblast co-culture and ECs 3D culture models, we demonstrate a further role for TG2 in both endothelial tubule formation and in tubule loss, which involves its role in the regulation of transforming growth factor β1 (TGFβ1) and Smad signalling. We demonstrate that inhibition of tubule formation by TG2 inhibitors can be restored by add-back of exogenous TGFβ1 at pg/ml levels and show that TG2 -/- mouse ECs are unable to form tubules in 3D culture and display negligible Smad signalling compared to wild-type cells. Loss of tubule formation in the TG2 -/- ECs can be reconstituted by transduction with TG2. We demonstrate that extracellular TG2 also has an important role in TGFβ1-induced transition of ECs into myofibroblast-like cells (endothelial-mesenchymal transition), resulting in loss of EC tubules and tubule formation. Our data also indicate that TG2 may have a role in regulating TGFβ signalling through entrapment of active TGFβ1 into the extracellular matrix. In conclusion, our work demonstrates that TG2 has multi-functional roles in ECs where its ability to fine-tune of TGFβ1 signalling means it can be involved in both endothelial tubule formation and tubule rarefaction.
Original language | English |
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Article number | e3032 |
Journal | Cell Death and Disease |
Volume | 8 |
Issue number | 9 |
DOIs | |
Publication status | Published - 7 Sept 2017 |
Bibliographical note
Cell Death and Disease is an open-access journal published by Nature Publishing Group. This work is licensed under a Creative Commons Attribution 4.0 International License. The images or other third party material in this article are included in the article’s Creative Commons license, unless indicated otherwise in the credit line; if the material is not included under the Creative Commons license, users will need to obtain permission from the license holder to reproduce the material. To view a copy of this license, visit http://creativecommons.org/licenses/by/4.0/Keywords
- Animals
- Cell Dedifferentiation/drug effects
- Coculture Techniques
- Epithelial Cells/cytology
- Fibroblasts/cytology
- GTP-Binding Proteins/deficiency
- Gene Expression Regulation
- Genetic Vectors/chemistry
- Human Umbilical Vein Endothelial Cells/cytology
- Humans
- Lentivirus/genetics
- Mice
- Mice, Knockout
- Mink
- Neovascularization, Physiologic/genetics
- Signal Transduction
- Smad Proteins/genetics
- Transforming Growth Factor beta1/genetics
- Transglutaminases/deficiency
- Wound Healing/genetics