Vascular permeability in retinopathy is regulated by VEGFR2 Y949 signaling to VE-cadherin

Abstract

Edema stemming from leaky blood vessels is common in eye diseases such as age-related macular degeneration and diabetic retinopathy. Whereas therapies targeting vascular endothelial growth factor A (VEGFA) can suppress leakage, side-effects include vascular rarefaction and geographic atrophy. By challenging mouse models representing different steps in VEGFA/VEGF receptor 2 (VEGFR2)-induced vascular permeability, we show that targeting signaling downstream of VEGFR2 pY949 limits vascular permeability in retinopathy induced by high oxygen or by laser-wounding. Although suppressed permeability is accompanied by reduced pathological neoangiogenesis in oxygen-induced retinopathy, similarly sized lesions leak less in mutant mice, separating regulation of permeability from angiogenesis. Strikingly, vascular endothelial (VE)-cadherin phosphorylation at the Y685, but not Y658, residue is reduced when VEGFR2 pY949 signaling is impaired. These findings support a mechanism whereby VE-cadherin Y685 phosphorylation is selectively associated with excessive vascular leakage. Therapeutically, targeting VEGFR2-regulated VE-cadherin phosphorylation could suppress edema while leaving other VEGFR2-dependent functions intact.

AMP-activated protein kinase is a key regulator of acute neurovascular permeability

“…We confirmed the phosphorylation of eNOS on S1177 downstream of AMPK both during VEGF-A and BK permeability induction. Interestingly, the Ca 2+ /AMPK/eNOS pathway resulted in the phosphorylation of VE-cad on Y685, identified previously as key for vascular permeability in the periphery 15 and the retina 16 , thus providing a direct link between AMPK and paracellular junction regulation. For retinal permeability, occludin phosphorylation and internalisation also plays an important role.…”

“…However, systematic correlation of cryo-immuno EM to leaky microvessels proved impractical. We therefore used phosphorylation of VE-cad on Y685 as a surrogate marker for retinal microvessel permeability 16 , in particular since such VE-cad phosphorylation is also a prerequisite for internalisation after BK treatment 15 . VEGF-A or BK stimulation of ex vivo retinae induced tyrosine phosphorylation of VE-cad on Y685 in intact microvessels (Figure 7b).…”

“…Ca 2+ transients, phosphorylation of the MAP kinase p38 and enhanced actin contractility are associated with all vascular permeability, as is activation of eNOS 11,12,13,14 . Adherens and tight junction modulation is associated with paracellular permeability and the phosphorylation of VE-cadherin (VE-cad) is associated with acute permeability in the periphery and the retina 15, 16 In the retina the phosphorylation of occludin on S490 and its subsequent internalisation also plays an important role, at least in a more chronic setting 17 . Identifying core signalling, on which all leakage responses depend, is desirable for therapeutic development as it would allow treatment without prior knowledge of specific known (or unknown) extracellular PIF.…”

Suppressed Vascular Leakage and Myocardial Edema Improve Outcome From Myocardial Infarction

“…The VEGFR2 Y949 phosphorylation site been implicated in regulation of the vascular barrier in different organs and in diseases such as cancer and retinopathy (Li et al, 2016;Smith et al, 2020). The potential impact of the pY949 pathway on the coronary circulation and on cardiac function has not been explored.…”

“…Hearts were lysed and samples processed for immunoblotting. Phosphorylation on Y685 in VE-cadherin correlates with vascular permeability (Orsenigo et al, 2012;Wessel et al, 2014;Smith et al, 2020). Levels of pY685 in VE-cadherin in the heart endothelium increased at 2-5 min after VEGFA injection in the wild-type, whereafter it returned to basal levels.…”