Wong Donald, Dorovini-Zis Katerina, Vincent Steven R
Department of Pathology and Laboratory Medicine, The University of British Columbia, Vancouver, BC, Canada V6T 1Z3.
Exp Neurol. 2004 Dec;190(2):446-55. doi: 10.1016/j.expneurol.2004.08.008.
The endothelial cells (EC) of the microvasculature in the brain form the anatomical basis of the blood-brain barrier (BBB). In the present study, the effects of agents that modify the permeability of a well-established in vitro model of the human BBB were studied. The monolayers formed by confluent human brain microvessel endothelial cell (HBMEC) cultures are impermeable to the macromolecule tracer horseradish peroxidase (HRP) and have high electrical resistance. Exposure of HBMEC to various cytokines including TNF-alpha, IL-1beta, interferon gamma (IFN-gamma), or lipopolysaccharide (LPS) decreased transendothelial electrical resistance (TEER) mainly by increasing the permeability of the tight junctions. Primary cultures of HBMEC express endothelial nitric oxide synthase (eNOS) and produce low levels of NO. Treatment with the NO donors sodium nitroprusside (SNP) and DETA NONOate or the cGMP agonist 8-Br-cGMP significantly increased monolayer resistance. Conversely, inhibition of soluble guanylyl cyclase with ODQ rapidly decreased the resistance, and pretreatment of HBMEC with Rp-8-CPT-cGMPS, an inhibitor of cGMP-dependent protein kinase, partially prevented the 8-Br-cGMP-induced increase in resistance. Furthermore, NO donors and 8-Br-cGMP could also reverse the increased permeability of the monolayers induced by IL-1beta, IFN-gamma, and LPS. These results indicate that NO can decrease the permeability of the human BBB through a mechanism at least partly dependent on cGMP production and cGMP-dependent protein kinase activation.
脑微血管的内皮细胞（EC）构成了血脑屏障（BBB）的解剖学基础。在本研究中，我们研究了改变成熟的人血脑屏障体外模型通透性的药物的作用。汇合的人脑微血管内皮细胞（HBMEC）培养形成的单层对大分子示踪剂辣根过氧化物酶（HRP）不可渗透，并且具有高电阻。将HBMEC暴露于包括肿瘤坏死因子-α、白细胞介素-1β、干扰素-γ（IFN-γ）或脂多糖（LPS）在内的各种细胞因子下，主要通过增加紧密连接的通透性来降低跨内皮电阻（TEER）。HBMEC的原代培养物表达内皮型一氧化氮合酶（eNOS）并产生低水平的NO。用NO供体硝普钠（SNP）和DETA NONOate或cGMP激动剂8-溴-cGMP处理可显著增加单层电阻。相反，用ODQ抑制可溶性鸟苷酸环化酶可迅速降低电阻，用cGMP依赖性蛋白激酶抑制剂Rp-8-CPT-cGMPS预处理HBMEC可部分阻止8-溴-cGMP诱导的电阻增加。此外，NO供体和8-溴-cGMP还可逆转由白细胞介素-1β、干扰素-γ和LPS诱导的单层通透性增加。这些结果表明，NO可通过至少部分依赖于cGMP生成和cGMP依赖性蛋白激酶激活的机制降低人血脑屏障的通透性。
