The role of plasmalemma vesicle-associated protein (PLVAP) in endothelial cells of Schlemm's canal and ocular capillaries
The role of plasmalemma vesicle-associated protein (PLVAP) in endothelial cells of Schlemm's canal and ocular capillaries
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DOI：
10.1016/j.exer.2012.09.011
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发表时间：
2012-12-01
影响因子：
3.4
通讯作者：
Tamm, Ernst R.
中科院分区：
文献类型：
--
作者：
Herrnberger, Leonie;Ebner, Kathrin;Tamm, Ernst R.
质膜囊泡相关蛋白（Plasmalemma vesicle-associated protein， PLVAP, PV-1）是一种内皮蛋白，特异定位于开孔毛细血管的开孔隔膜和小泡的气孔隔膜。我们观察了PLVAP在施勒姆管内皮和眼毛细血管中的定位，并研究了PLVAP缺乏对眼毛细血管结构的影响。在小鼠、猪和人眼中，PLVAP在脉络膜和睫状肌的开孔毛细血管中存在免疫反应性，而在视网膜和睫状肌的连续毛细血管中不存在免疫反应性。三种动物房水流出血管的内皮均可见PLVAP染色，如施莱姆管（SC，小鼠和人）、水丛（AP，猪）和巩膜集电通道。当在Plvap位点插入LacZ的突变型杂合和纯合Plvap缺陷小鼠中研究β -半乳糖苷酶的表达时，基本上观察到类似的结果。通过透射电镜观察，SC内皮细胞的绝大多数小泡显示有气孔隔膜。此外，在所有三种的SC或AP中偶尔观察到孤窗或带隔膜的微孔。相比之下，突变体Plvap（-/-）小鼠在SC小泡中完全没有气孔，没有观察到SC微孔。此外，纤毛突或绒毛膜毛细血管内皮细胞的小窗中没有膈肌，这一发现与小窗数量的显著减少有关。PLVAP在Schlemm管内皮细胞中表达，在眼血管内皮细胞中对横膈膜的形成至关重要。(C) 2012 Elsevier Ltd.版权所有。
Plasmalemma vesicle-associated protein (PLVAP, PV-1) is an endothelial protein that specifically localizes to diaphragms of fenestrae in fenestrated capillaries, and to stomatal diaphragms of caveolae. Here we investigated the localization of PLVAP in Schlemm's canal endothelium and ocular capillaries, and studied the structural effects of PLVAP deficiency. In mouse, pig and human eyes, immunoreactivity for PLVAP was present in fenestrated capillaries of choroid and ciliary processes, but not in the continuous capillaries of retina and ciliary muscle. In all three species staining for PLVAP was seen in the endothelia of the outflow vessels of aqueous humor e.g. Schlemm's canal (SC, mouse and human), aqueous plexus (AP, pig) and the scleral collector channels. Essentially comparable findings were observed when the expression of beta-galactosidase was investigated in mutant heterozygous and homozygous PLVAP-deficient mice with LacZ inserted into the Plvap locus. By transmission electron microscopy, the vast majority of caveolae in SC endothelial cells showed a stomatal diaphragm. In addition, solitary fenestrae or mini-pores with a diaphragm were occasionally observed in SC or AP of all three species. In contrast, mutant Plvap(-/-) mice showed a complete absence of stomatal diaphragms in SC caveolae while no SC minipores were observed. Moreover, diaphragms were absent in fenestrae of endothelial cells in the capillaries of the ciliary processes or the choriocapillaris, findings which were associated with a substantial decrease in the number of fenestrae. PLVAP is expressed in endothelial cells of Schlemm's canal and is essential for the formation of diaphragms in vascular endothelial cells of the eye. (C) 2012 Elsevier Ltd. All rights reserved.