Identification of two phosphorylation sites essential for annexin A1 in blood–brain barrier protection after experimental intracerebral hemorrhage in rats
Identification of two phosphorylation sites essential for annexin A1 in blood–brain barrier protection after experimental intracerebral hemorrhage in rats
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DOI：
10.1177/0271678x16669513
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发表时间：
2017-07
影响因子：
6.3
通讯作者：
Zhong Wang;Zhouqing Chen;Junjie Yang;Ziying Yang;Jia Yin;Gang Zuo;Xiaochun Duan;Haitao Shen;Haiying Li;Gang Chen
中科院分区：
文献类型：
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作者：
Zhong Wang;Zhouqing Chen;Junjie Yang;Ziying Yang;Jia Yin;Gang Zuo;Xiaochun Duan;Haitao Shen;Haiying Li;Gang Chen
据报道，膜联蛋白A1发挥血脑屏障保护作用。本研究旨在探讨膜联蛋白A1在脑内血肿诱导的血脑屏障功能障碍中的作用。在成年雄性Sprague道利大鼠中进行胶原酶脑出血模型。首先，通过脑出血大鼠脑血管内皮和血清中膜联蛋白A1的丢失，以及体内静脉注射人重组膜联蛋白A1和体外膜联蛋白A1过表达对暴露于脑出血刺激的脑微血管内皮细胞屏障功能的拯救作用，证实了膜联蛋白A1与脑出血病理之间的可能关系。其次，我们发现脑出血显著增加膜联蛋白A1丝氨酸/苏氨酸残基的磷酸化比率。最后，基于位点特异性突变，我们确定了两个磷酸化位点：（a）膜联蛋白A1在苏氨酸24处的磷酸化是其与肌动蛋白细胞骨架相互作用所必需的，（B）丝氨酸27处的磷酸化是膜联蛋白A1分泌所必需的，这两个位点对于维持细胞骨架的完整性和细胞旁通透性都是必需的。总之，膜联蛋白A1可通过苏氨酸24和丝氨酸27磷酸化依赖性方式预防脑内血肿诱导的血脑屏障功能障碍。膜联蛋白A1磷酸化可能是脑出血后脑微血管内皮细胞的一种自助策略;然而，脑出血诱导的膜联蛋白A1丢失几乎完全消除了这种策略。
Annexin A1 has been reported to exert a blood–brain barrier protection. This study was designed to examine the role of annexin A1 in intracerebral hemorrhage-induced blood–brain barrier dysfunction. A collagenase intracerebral hemorrhage model was performed in adult male Sprague Dawley rats. First, a possible relationship between annexin A1 and intracerebral hemorrhage pathology was confirmed by a loss of annexin A1 in the cerebrovascular endothelium and serum of intracerebral hemorrhage rats, and the rescue effects of i.v. administration of human recombinant annexin A1 in vivo and annexin A1 overexpression in vitro on the barrier function of brain microvascular endothelial cells exposed to intracerebral hemorrhage stimulus. Second, we found that intracerebral hemorrhage significantly increased the phosphorylation ratio of annexin A1 at the serine/threonine residues. Finally, based on site-specific mutagenesis, we identified two phosphorylation sites (a) annexin A1 phosphorylation at threonine 24 is required for its interaction with actin cytoskeleton, and (b) phosphorylation at serine27 is essential for annexin A1 secretion, both of which were essential for maintaining cytoskeleton integrity and paracellular permeability. In conclusion, annexin A1 prevents intracerebral hemorrhage-induced blood–brain barrier dysfunction in threonine 24 and serine27 phosphorylation-dependent manners. Annexin A1 phosphorylation may be a self-help strategy in brain microvascular endothelial cells after intracerebral hemorrhage; however, that was almost completely abolished by the intracerebral hemorrhage-induced loss of annexin A1.