Di Lorenzo Annarita, Lin Michelle I, Murata Takahisa, Landskroner-Eiger Shira, Schleicher Michael, Kothiya Milankumar, Iwakiri Yasuko, Yu Jun, Huang Paul L, Sessa William C
Department of Pharmacology and Vascular Biology and Therapeutics Program, Yale University School of Medicine, New Haven, CT 06520, USA.
J Cell Sci. 2013 Dec 15;126(Pt 24):5541-52. doi: 10.1242/jcs.115972. Epub 2013 Sep 17.
Transient disruption of endothelial adherens junctions and cytoskeletal remodeling are responsible for increases in vascular permeability induced by inflammatory stimuli and vascular endothelial growth factor (VEGF). Nitric oxide (NO) produced by endothelial NO synthase (eNOS) is crucial for VEGF-induced changes in permeability in vivo; however, the molecular mechanism by which endogenous NO modulates endothelial permeability is not clear. Here, we show that the lack of eNOS reduces VEGF-induced permeability, an effect mediated by enhanced activation of the Rac GTPase and stabilization of cortical actin. The loss of NO increased the recruitment of the Rac guanine-nucleotide-exchange factor (GEF) TIAM1 to adherens junctions and VE-cadherin (also known as cadherin 5), and reduced Rho activation and stress fiber formation. In addition, NO deficiency reduced VEGF-induced VE-cadherin phosphorylation and impaired the localization, but not the activation, of c-Src to cell junctions. The physiological role of eNOS activation is clear given that VEGF-, histamine- and inflammation-induced vascular permeability is reduced in mice bearing a non-phosphorylatable knock-in mutation of the key eNOS phosphorylation site S1176. Thus, NO is crucial for Rho GTPase-dependent regulation of cytoskeletal architecture leading to reversible changes in vascular permeability.
内皮黏附连接的短暂破坏和细胞骨架重塑是炎症刺激和血管内皮生长因子（VEGF）诱导血管通透性增加的原因。内皮型一氧化氮合酶（eNOS）产生的一氧化氮（NO）对于VEGF在体内诱导的通透性变化至关重要；然而，内源性NO调节内皮通透性的分子机制尚不清楚。在此，我们表明eNOS的缺失会降低VEGF诱导的通透性，这一效应是由Rac GTP酶的激活增强和皮质肌动蛋白的稳定介导的。NO的缺失增加了Rac鸟嘌呤核苷酸交换因子（GEF）TIAM1向黏附连接和血管内皮钙黏蛋白（也称为钙黏蛋白5）的募集，并减少了Rho激活和应力纤维形成。此外，NO缺乏会降低VEGF诱导的血管内皮钙黏蛋白磷酸化，并损害c-Src在细胞连接处的定位，但不影响其激活。鉴于在携带关键eNOS磷酸化位点S1176的不可磷酸化敲入突变的小鼠中，VEGF、组胺和炎症诱导的血管通透性降低，eNOS激活的生理作用是明确的。因此，NO对于Rho GTP酶依赖性调节细胞骨架结构导致血管通透性的可逆变化至关重要。
