The Bartonella henselae VirB/Bep system interferes with vascular endothelial growth factor (VEGF) signalling in human vascular endothelial cells
| Autor: | Scheidegger Florine, Quebatte Maxime, Mistl Claudia, Dehio Christoph |
|---|---|
| Rok vydání: | 2010 |
| Předmět: |
Vascular Endothelial Growth Factor A
Bartonella henselae Phospholipase C gamma Blotting Western Immunoblotting Endothelial Cells Polymerase Chain Reaction Vascular Endothelial Growth Factor Receptor-2 Bacterial Proteins Humans Calcium Electrophoresis Polyacrylamide Gel Mitogen-Activated Protein Kinases Phosphorylation Vanadates Signal Transduction |
| Zdroj: | Cellular microbiology |
| ISSN: | 1462-5822 |
| Popis: | The vasculotropic pathogen Bartonella henselae (Bh) intimately interacts with human endothelial cells (ECs) and subverts multiple cellular functions. Here we report that Bh specifically interferes with vascular endothelial growth factor (VEGF) signalling in ECs. Bh infection abrogated VEGF-induced proliferation and wound closure of EC monolayers as well as the capillary-like sprouting of EC spheroids. On the molecular level, Bh infection did not alter VEGF receptor 2 (VEGFR2) expression or cell surface localization, but impeded VEGF-stimulated phosphorylation of VEGFR2 at tyrosine(1175) . Consistently, we observed that Bh infection diminished downstream events of the tyrosine(1175) -dependent VEGFR2-signalling pathway leading to EC proliferation, i.e. phospholipase-Cγ activation, cytosolic calcium fluxes and mitogen-activated protein kinase ERK1/2 phosphorylation. Pervanadate treatment neutralized the inhibitory activity of Bh on VEGF signalling, suggesting that Bh infection may activate a phosphatase that alleviates VEGFR2 phosphorylation. Inhibition of VEGFR2 signalling by Bh infection was strictly dependent on a functional VirB type IV secretion system and thereby translocated Bep effector proteins. The data presented in this study underscore the role of the VirB/Bep system as important factor controlling EC proliferation in response to Bh infection; not only as previously reported by counter-acting an intrinsic bacterial mitogenic stimulus, but also by restricting the exogenous angiogenic stimulation by Bh-induced VEGF. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
|