VEGF-A isoforms differentially regulate ATF-2-dependent VCAM-1 gene expression and endothelial-leukocyte interactions

• Published in: Molecular biology of the cell Vol. 25; no. 16; pp. 2509 - 2521
• Main Authors: Fearnley, Gareth W, Odell, Adam F, Latham, Antony M, Mughal, Nadeem A, Bruns, Alexander F, Burgoyne, Nicholas J, Homer-Vanniasinkam, Shervanthi, Zachary, Ian C, Hollstein, Monica C, Wheatcroft, Stephen B, Ponnambalam, Sreenivasan
• Format: Journal Article
• Language: English
• Published: United States The American Society for Cell Biology 15.08.2014
• Subjects: Activating Transcription Factor 2 - genetics; Activating Transcription Factor 2 - metabolism; Cell Movement; Cell Proliferation; Gene Expression; Humans; Leukocytes - metabolism; MAP Kinase Signaling System; Phosphorylation; Protein Isoforms - genetics; Protein Isoforms - metabolism; Vascular Cell Adhesion Molecule-1 - genetics; Vascular Cell Adhesion Molecule-1 - metabolism; Vascular Endothelial Growth Factor A - genetics; Vascular Endothelial Growth Factor A - metabolism; Vascular Endothelial Growth Factor Receptor-2 - genetics; Vascular Endothelial Growth Factor Receptor-2 - metabolism
• ISSN: 1059-1524; 1939-4586
• DOI: 10.1091/mbc.E14-05-0962

Vascular endothelial growth factor A (VEGF-A) regulates many aspects of vascular physiology. VEGF-A stimulates signal transduction pathways that modulate endothelial outputs such as cell migration, proliferation, tubulogenesis, and cell-cell interactions. Multiple VEGF-A isoforms exist, but the biological significance of this is unclear. Here we analyzed VEGF-A isoform-specific stimulation of VCAM-1 gene expression, which controls endothelial-leukocyte interactions, and show that this is dependent on both ERK1/2 and activating transcription factor-2 (ATF-2). VEGF-A isoforms showed differential ERK1/2 and p38 MAPK phosphorylation kinetics. A key feature of VEGF-A isoform-specific ERK1/2 activation and nuclear translocation was increased phosphorylation of ATF-2 on threonine residue 71 (T71). Using reverse genetics, we showed ATF-2 to be functionally required for VEGF-A-stimulated endothelial VCAM-1 gene expression. ATF-2 knockdown blocked VEGF-A-stimulated VCAM-1 expression and endothelial-leukocyte interactions. ATF-2 was also required for other endothelial cell outputs, such as cell migration and tubulogenesis. In contrast, VCAM-1 was essential only for promoting endothelial-leukocyte interactions. This work presents a new paradigm for understanding how soluble growth factor isoforms program complex cellular outputs and responses by modulating signal transduction pathways.