Hyperosmotic mannitol induces Src kinase-dependent phosphorylation of β-catenin in cerebral endothelial cells
Hyperosmotic mannitol induces Src kinase-dependent phosphorylation of β-catenin in cerebral endothelial cells
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DOI：
10.1002/jnr.20521
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发表时间：
2005-06-15
影响因子：
4.2
通讯作者：
Krizbai, IA
中科院分区：
文献类型：
--
作者：
Farkas, A;Szatmári, E;Krizbai, IA
甘露醇是一种细胞不透性、无毒的多元醇，已被证明是可逆地开放血脑屏障(BBB)的有用工具。尽管临床试验取得了成功，但甘露醇诱导脑内皮细胞(CECs)变化的分子机制尚不清楚。在我们的实验中，我们使用培养的CECs，用不同的临床相关浓度的甘露醇处理。我们发现甘露醇可诱导50-190 kDa范围内多种蛋白质的快速、浓度依赖和可逆的酪氨酸磷酸化。酪氨酸磷酸化的靶点之一是粘着连接蛋白β-连环蛋白。免疫共沉淀研究表明，β-连环蛋白在酪氨酸残基上的磷酸化导致其在亚细胞内重新分布，并与钙粘蛋白和α-连环蛋白解离。所有这些作用均可被Src激酶抑制剂PP-1所抑制，但不能被ERK抑制剂U0126、Rho激酶抑制剂Y27632或钙通道阻滞剂维拉帕米所抑制。由于β-连环蛋白是连接复合体的关键成分，其由Src介导的磷酸化可能在甘露醇诱导的血脑屏障可逆性开放中发挥重要作用。(C)2005年Wiley-Liss，Inc.
Mannitol, which is a cell-impermeable and nontoxic polyalcohol, has been shown to be a useful tool for reversible opening of the blood-brain barrier (BBB). Despite successful clinical trials, the molecular mechanism of the mannitol-induced changes in cerebral endothelial cells (CECs) are poorly understood. For our experiments, we used CECs in culture, which were treated with different, clinically relevant concentrations of mannitol. We found that mannitol induced a rapid, concentration-dependent, and reversible tyrosine phosphorylation of a broad range of proteins between 50 and 190 kDa. One of the targets of tyrosine phosphorylation turned out to be the adherens junction protein beta-catenin. Phosphorylation of beta-catenin on tyrosine residues caused its subcellular redistribution and its dissociation from cadherin and alpha-catenin as shown by coimmunoprecipitation studies. All these effects could be inhibited by the Src kinase inhibitor PP-1 but not by the Erk inhibitor U0126, the Rho kinase inhibitor Y27632, or the calcium channel blocker verapamil. Because beta-catenin is a key component of the junctional complex, its Src-mediated phpsphorylation may play an important role in the mannitol induced reversible opening of the BBB. (c) 2005 Wiley-Liss, Inc.