Center for Vascular Biology, Department of Cell Biology (K.N.P., K.P.C.), University of Connecticut Health Center, Farmington.
Pat and Jim Calhoun Cardiology Center (Z.Y., L.Y., C.G.C., B.T.L.), University of Connecticut Health Center, Farmington.
Arterioscler Thromb Vasc Biol. 2022 Oct;42(10):1229-1241. doi: 10.1161/ATVBAHA.122.317645. Epub 2022 Jul 21.
Regulation of vascular permeability is critical to maintaining tissue metabolic homeostasis. VEGF (vascular endothelial growth factor) is a key stimulus of vascular permeability in acute and chronic diseases including ischemia reperfusion injury, sepsis, and cancer. Identification of novel regulators of vascular permeability would allow for the development of effective targeted therapeutics for patients with unmet medical need.
In vitro and in vivo models of VEGFA-induced vascular permeability, pathological permeability, quantitation of intracellular calcium release and cell entry, and phosphatidylinositol 4,5-bisphosphate levels were evaluated with and without modulation of PLC (phospholipase C) β2.
Global knock-out of in mice resulted in blockade of VEGFA-induced vascular permeability in vivo and transendothelial permeability in primary lung endothelial cells. Further work in an immortalized human microvascular cell line modulated with stable knockdown 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 phosphatidylinositol 4,5-bisphosphate 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 with wild-type controls.
The results implicate PLCβ2 as a key positive regulator of VEGF-induced vascular permeability through regulation of both calcium flux and phosphatidylinositol 4,5-bisphosphate levels at the cellular level. Targeting of PLCβ2 in a therapeutic setting may provide a novel approach to regulating vascular permeability in patients.
血管通透性的调节对于维持组织代谢稳态至关重要。VEGF（血管内皮生长因子）是急性和慢性疾病中血管通透性的关键刺激物，包括缺血再灌注损伤、脓毒症和癌症。鉴定新的血管通透性调节剂将为有未满足医疗需求的患者开发有效的靶向治疗方法。
在体外和体内 VEGFA 诱导的血管通透性、病理性通透性、细胞内钙释放和细胞进入的定量以及磷脂酰肌醇 4,5-二磷酸水平的模型中，评估了在没有和有 PLC（磷脂酶 C）β2 调节的情况下的变化。
在小鼠中敲除 导致体内 VEGFA 诱导的血管通透性和原代肺内皮细胞的跨内皮通透性受阻。在稳定敲低 PLCβ2 的永生化人微血管细胞系中的进一步工作重现了小鼠模型和原代细胞测定中的观察结果。此外，与对照细胞相比，PLCβ2 的缺失限制了 VEGF 刺激后的细胞内钙释放和细胞外进入，以及基础和 VEGFA 刺激的磷脂酰肌醇 4,5-二磷酸水平。最后，与野生型对照相比，在高氧诱导的肺通透性模型和心脏缺血再灌注模型中，PLCβ2 的缺失导致动物结局得到改善。
结果表明，PLCβ2 通过调节细胞水平的钙通量和磷脂酰肌醇 4,5-二磷酸水平，是 VEGF 诱导的血管通透性的关键正调节剂。在治疗环境中靶向 PLCβ2 可能为调节患者血管通透性提供一种新方法。
