Phospholipase Cβ2 Promotes Vascular Endothelial Growth Factor Induced Vascular Permeability

Abstract

AbstractBackgroundRegulation of vascular permeability (VP) is critical to maintaining tissue metabolic homeostasis. Vascular endothelial growth factor (VEGF) is a key stimulus of VP in acute and chronic diseases including ischemia reperfusion injury, sepsis and cancer. Identification of novel regulators of VP would allow for the development of effective targeted therapeutics for patients with unmet medical need.MethodsIn vitro and in vivo models of VEGFA-induced vascular permeability, pathological permeability, quantitation of intracellular calcium release and cell entry, and PIP2 levels were evaluated with and without modulation of PLCβ2.ResultsGlobal knock-out of PLCβ2 in mice resulted in blockade of VEGFA-induced vascular permeability in vivo and trans-endothelial permeability in primary lung endothelial cells. Further work in an immortalized human microvascular cell line modulated with stable knock-down of PLCβ2 recapitulated the observations in the mouse model and primary cell assays. Additionally, loss of PLCβ2 limited both intracellular release and extracellular entry of calcium following VEGF stimulation as well as reduced basal and VEGFA-stimulated levels of PIP2 compared to control cells. Finally, loss of PLCβ2 in both a hyperoxia induced lung permeability model and a cardiac ischemia:reperfusion model resulted in improved animal outcomes when compared to WT controls.ConclusionsThe results implicate PLCβ2 as a key positive regulator of VEGF-induced VP through regulation of both calcium flux and PIP2 levels at the cellular level. Targeting of PLCβ2 in a therapeutic setting may provide a novel approach to regulating vascular permeability in patients.Graphic AbstractHighlightsPLCβ2 promotes VEGFA induced vascular permeability.Loss of PLCβ2 prevents VEGFA vascular permeability via repression of cellular calcium flux and membrane PIP2 levels.Loss of PLCβ2 reduces vascular permeability and improves outcomes in a hyperoxic lung damage model and a cardiac ischemia:reperfusion model in vivo.Targeting PLCβ2 inhibition may lead to a novel therapeutic for diseases such as stroke and myocardial infarction.