Neutrophil-derived glutamate regulates vascular endothelial barrier function
Neutrophil-derived glutamate regulates vascular endothelial barrier function
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DOI：
10.1074/jbc.m110557200
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发表时间：
2002-04-26
影响因子：
4.8
通讯作者：
Colgan, SP
中科院分区：
文献类型：
--
作者：
Collard, CD;Park, KA;Colgan, SP
内皮屏障功能在炎症状态下通过释放可溶性多形核白细胞（PMN）衍生的介质而改变。然而，内源性途径来描述这种变化是最近才认识到的。使用体外内皮细胞旁通透性模型，观察到甲酰甲硫氨酰亮氨酰苯丙氨酸刺激的中性粒细胞的无细胞上清液显着改变内皮通透性。PMN上清液的生物物理和生物化学分析确定PMN衍生的谷氨酸调节内皮通透性。此外，新的表达代谢型谷氨酸受体1（mGluR 1），mGluR 4，和mGluR 5的人脑和真皮微血管内皮细胞被证明通过逆转录-PCR，原位杂交，免疫荧光，和Western印迹分析。用谷氨酸盐或选择性mGluR组I或III激动剂治疗人脑内皮细胞导致磷酸化血管舒张刺激磷蛋白（VASP）的时间依赖性损失，并显著增加内皮细胞通透性。用选择性mGluR拮抗剂预处理人脑内皮细胞，可显著减弱谷氨酸诱导的脑内皮屏障功能和磷酸化VASP的降低。这些观察结果扩展到体内缺氧小鼠模型，其中用mGluR拮抗剂预处理显著降低了异硫氰酸荧光素-葡聚糖穿过血脑屏障的通量。我们的结论是，激活的人中性粒细胞释放谷氨酸和内皮表达的第一组或第三组mGluRs功能，以减少人脑内皮VASP磷酸化和屏障功能。这些结果确定了一种新的途径，PMN衍生的谷氨酸盐可以调节人类内皮屏障功能。
Endothelial barrier function is altered by the release of soluble polymorphonuclear leukocyte (PMN)-derived mediators during inflammatory states. However, endogenous pathways to describe such changes are only recently appreciated. Using an in vitro endothelial paracellular permeability model, cell-free supernatants from formylmethionylleucylphenylalanine-stimulated PMNs were observed to significantly alter endothelial permeability. Biophysical and biochemical analysis of PMN supernatants identified PMN-derived glutamate in modulating endothelial permeability. Furthermore, novel expression of metabotropic glutamate receptor 1 (mGluR1), mGluR4, and mGluR5 by human brain and dermal microvascular endothelial cells was demonstrated by reverse transcription-PCR, in situ hybridization, immunofluorescence, and Western blot analysis. Treatment of human brain endothelia with glutamate or selective, mGluR group I or III agonists resulted in a time-dependent loss of phosphorylated vasodilator-stimulated phosphoprotein (VASP) and significantly increased endothelial permeability. Glutamate-induced decreases in brain endothelial barrier function and phosphorylated VASP were significantly attenuated by pretreatment of human brain endothelia with selective mGluR antagonists. These observations were extended to an in vivo hypoxic mouse model in which pretreatment with mGluR antagonists significantly decreased fluorescein isothiocyanate-dextran flux across the blood-brain barrier. We conclude that activated human PMNs release glutamate and that endothelial expression of group I or III mGluRs function to decrease human brain endothelial VASP phosphorylation and barrier function. These results identify a novel pathway by which PMN-derived glutamate may regulate human endothelial barrier function.