Rip2 modifies VEGF-induced signalling and vascular permeability in myocardial ischaemia

Aims In myocardial ischaemia, vascular endothelial growth factor (VEGF) induces permeability by activating a signalling path- way that includes VEGF receptor 2 (VEGFR2), resulting in increased oedema and inflammation and thereby expanding the area of tissue damage. In this study, we investigated the role of receptor-interacting protein 2 (Rip2) in VEGF sig- nalling and myocardial ischaemia/reperfusion injury. Methods To determine whether Rip2 has a role in VEGF signalling, we used cultured endothelial cells in which Rip2 was or was and results not inactivated. In Rip2-deficient endothelial cells, stimulation with VEGF resulted in more rapid kinetics of VEGFR2 phosphorylation than in control cells. Rip2 deficiency also enhanced VEGF-induced activation of ERK1/2, suggesting an increased propensity for endothelial permeability. In a mouse model of myocardial ischaemia, Rip2 deficiency re- sulted in enhanced vascular permeability, increased oedema and expanding area of myocardial damage, and markedly reduced heart function after long-term follow-up. Conclusion Our results show that Rip2 modifies VEGF-induced signalling and vascular permeability in myocardial ischaemia. These findings indicate that Rip2 may be a promising novel therapeutic target to reduce excess vascular permeability in ischae- mic heart disease.