Inflammation- and ischemia-induced shedding of venular glycocalyx
Inflammation- and ischemia-induced shedding of venular glycocalyx
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DOI：
10.1152/ajpheart.00832.2003
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发表时间：
2004-05-01
影响因子：
4.8
通讯作者：
Lipowsky, HH
中科院分区：
文献类型：
--
作者：
Mulivor, AW;Lipowsky, HH
在炎症和缺血再灌注损伤模型中，探讨了毛细血管后微静脉（大鼠肠系膜）微静脉内皮糖萼组成的变化。凝集素共价连接到荧光标记的微球（0.1 μ m直径）或直接用FITC标记。粘附特异性的葡萄糖和半乳糖残基的糖胺聚糖（GAGs）和其他成分的内皮glycocalyx显着降低后灌注的肠系膜与化学引诱剂N-甲酰甲硫氨酰-亮氨酰-苯丙氨酸和60分钟缺血后再灌注过程中的凝集素。这些减少显着减弱与百日咳毒素（PTX）灌流，表明脱落的糖萼介导的G蛋白。与多配体蛋白聚糖-1（GAG结合的主要蛋白聚糖）的抗体连接的微球的粘附揭示了随着GAG丢失而增加的标记，并且允许更多数量的球粘附到蛋白质核心，其不脱落。闭塞近端微血管60分钟诱导缺血导致内皮细胞上半乳糖胺聚糖增加40%，葡糖胺聚糖增加15%，PTX不抑制。血管再灌注导致GAG的快速丢失，这被PTX预处理抑制，40%的半乳糖胺聚糖和25%的葡糖胺聚糖积累被G蛋白介导的脱落去除，其余的通过流体剪切自由对流离开。我们的结论是，糖萼的组合物的结果从平衡的速率的生物合成的糖胺聚糖的内皮细胞和他们的脱落，这可能是介导的细胞内和/或膜结合的蛋白酶或裂解酶释放或激活的G蛋白信号。
Alterations in the composition of the glycocalyx of venular endothelium in postcapillary venules (rat mesentery) were explored in models of inflammation and ischemia-reperfusion injury. Lectins were covalently linked to fluorescently labeled microspheres (0.1-mum diameter) or directly labeled with FITC. Adhesion of lectins specific for glucose and galactose residues of glycosaminoglycans (GAGs) and other components of the endothelial glycocalyx decreased dramatically after superfusion of the mesentery with the chemoattractant N-formylmethionyl-leucyl-phenylalanine and during reperfusion after 60-min ischemia. These reductions were significantly attenuated by superfusion with pertussis toxin (PTX), suggesting that shedding of glycocalyx was mediated by G proteins. Adhesion of microspheres linked with antibody for syndecan-1, a major proteoglycan to which GAGs are bound, revealed increased labeling as GAGs were lost and permitted greater numbers of spheres to adhere to the protein core, which was not shed. Induction of ischemia by occluding proximal microvessels for 60 min resulted in a 40% increase in galactosaminoglycans and a 15% increase in glucosaminoglycans on the endothelium, which was not inhibited by PTX. Reperfusion of vessels led to a rapid loss of GAGs that was inhibited by pretreatment with PTX, with 40% of galactosaminoglycans and 25% of glucosaminoglycans accumulated being removed by G protein-mediated shedding and the remainder freely convected away by fluid shear. We conclude that the composition of the glycocalyx results from a balance of the rate of biosynthesis of GAGs by the endothelial cell and their shedding, which may be mediated by intracellular and/or membrane-bound proteases or lyases released or activated by G protein signaling.