Apolipoprotein E Regulates the Integrity of Tight Junctions in an Isoform-dependent Manner in an in Vitro Blood-Brain Barrier Model
Apolipoprotein E Regulates the Integrity of Tight Junctions in an Isoform-dependent Manner in an in Vitro Blood-Brain Barrier Model
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DOI：
10.1074/jbc.m111.225532
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发表时间：
2011-05-20
影响因子：
4.8
通讯作者：
Michikawa, Makoto
中科院分区：
文献类型：
--
作者：
Nishitsuji, Kazuchika;Hosono, Takashi;Michikawa, Makoto
载脂蛋白E（apoE）是脑内主要的载脂蛋白。apoE基因的等位基因是阿尔茨海默病的主要危险因素，apoE缺乏可导致小鼠血脑屏障（BBB）渗漏。然而，apoE亚型对血脑屏障性质的影响尚不清楚。在这里，使用体外血脑屏障模型组成的脑内皮细胞和周细胞制备的野生型（WT）小鼠，和原代星形胶质细胞制备的人apoE 3-和apoE 4-敲入小鼠，我们表明，紧密连接（TJ）的屏障功能受损时，血脑屏障重建与原代星形胶质细胞apoE 4-敲入小鼠（apoE 4-血脑屏障模型）。与apoE 3- BBB模型相比，apoE 4-BBB模型中mBECs中occludin在Thr残基的磷酸化和蛋白激酶C（PKC）eta的活化减弱。apoE亚型对PKC eta活化、闭合蛋白在Thr残基的磷酸化和TJ完整性的差异效应在用抗低密度脂蛋白受体相关蛋白1（LRP 1）抗体或LRP 1拮抗剂受体相关蛋白治疗后被消除。与体外研究的结果一致，apoE 4敲入小鼠的BBB通透性高于apoE 3敲入小鼠。我们的研究提供的证据表明，TJ的完整性在血脑屏障是由apoE亚型依赖的方式。
Apolipoprotein E (apoE) is a major apolipoprotein in the brain. The epsilon 4 allele of apoE is a major risk factor for Alzheimer disease, and apoE deficiency in mice leads to blood-brain barrier (BBB) leakage. However, the effect of apoE isoforms on BBB properties are as yet unknown. Here, using an in vitro BBB model consisting of brain endothelial cells and pericytes prepared from wild-type (WT) mice, and primary astrocytes prepared from human apoE3- and apoE4-knock- in mice, we show that the barrier function of tight junctions (TJs) was impaired when the BBB was reconstituted with primary astrocytes from apoE4-knock- in mice (apoE4-BBB model). The phosphorylation of occludin at Thr residues and the activation of protein kinase C (PKC)eta in mBECs were attenuated in the apoE4-BBB model compared with those in the apoE3- BBB model. The differential effects of apoE isoforms on the activation of PKC eta, the phosphorylation of occludin at Thr residues, and TJ integrity were abolished following the treatment with an anti-low density lipoprotein receptor-related protein 1 (LRP1) antibody or a LRP1 antagonist receptor-associated protein. Consistent with the results of in vitro studies, BBB permeability was higher in apoE4-knock- in mice than in apoE3- knock-in mice. Our studies provide evidence that TJ integrity in BBB is regulated by apoE in an isoform-dependent manner.