mGluR1在蛛网膜下腔出血后脑损伤中的作用、分子机制及药物调控研究

The glutamate concentration of cerebrospinal fluid of patients suffering from SAH significantly increased, and was correlated with cerebral vasospasm and delayed cerebral ischemia. Metabotropic glutamate receptor 1 (mGluR1) played a essential role in glutamate-mediated excitotoxic damage. However, whether mGluR1 activation after SAH is protective or harmful was still elusive. Our preliminary study show that expression of mGluR1 increased after SAH, and its negative allosteric modulator (NAM) improved neurological function and attenuates blood-brain barrier permeability; its NAM also against glutamate-induced calcium overload and cell apoptosis in cultured primary neurons. Hence, this project was designed to investigate the possible role and mechanism of mGluR1 in glutamate-mediated excitotoxic damage, blood-brain barrier permeability, cerebral vasospasm and delayed cerebral ischemia following SAH in vivo and in vitro via using the agonist, positive allosteric modulator (PAM), NAM and Tat-mGluR1α peptide. Furthermore, this project was undertaken to explore the protective role and mechanism of NAM and Tat-mGluR1α peptide on brain injury after SAH, which has the potential for translation into clinical application.

临床发现蛛网膜下腔出血(SAH)患者脑脊液中谷氨酸浓度过高，且与脑血管痉挛及迟发性脑缺血相关。代谢型谷氨酸受体1(mGluR1)参与过量谷氨酸引发的兴奋性神经毒性，但在SAH后脑损伤中的作用还不清楚。我们前期研究发现：mGluR1在SAH后表达升高，其负向变构剂(NAM)明显改善SAH后神经功能缺损和血脑屏障通透性；原代培养神经元上mGluR1的NAM可对抗谷氨酸诱导的钙超载及细胞凋亡。因此，本项目将以mGluR1为靶点，以SAH后脑损伤为背景，通过离体细胞和整体动物实验，应用选择性性调控mGluR1的Agonist、正向变构剂(PAM)、NAM及Tat-mGluR1α短肽等手段来探究mGluR1在SAH后谷氨酸毒性及神经细胞凋亡、血脑屏障通透性、脑血管痉挛及脑缺血中的作用及分子机制。同时明确负向变构剂及Tat-mGluR1α多肽对SAH后脑损伤的保护作用及机理，使研究具有向临床转化的潜能

谷氨酸兴奋性毒性在蛛网膜下腔出血(SAH)后脑损伤病理生理过程中起着关键作用，但其精细作用机制还不明确。本项目分析动脉瘤性SAH患者的临床资料和脑脊液样本，观察到患者脑脊液中谷氨酸浓度过高，统计分析表明早期患者脑脊液中过高的谷氨酸与迟发性脑缺血(DCI)的发生具有相关性，同时发现SAH并发脑水肿的患者的脑脊液中谷氨酸浓度高于不并发脑水肿的患者。利用动物及细胞模型发现，谷氨酸兴奋性毒性-代谢性谷氨酸受体1亚型 (mGluR1)是治疗蛛网膜下腔出血潜在的新靶点，本项目研究了mGluR1介导的谷氨酸毒性影响SAH后病理发展的作用机制：①引起钙超载而介导神经元凋亡；②引起血脑屏障通透性升高而介导SAH后血管源性脑水肿；③介导脑血管痉挛及微血栓而引起迟发性脑缺血；④mGluR1a的C末端发生断裂而转化为促凋亡受体，引起长时程神经功能缺损。针对SAH后谷氨酸毒性—mGluR1靶点,我们研发了潜在药物干预措施：①可跨越血脑屏障的负向变构剂选择性抑制mGluR1；②自行设计的抑制mGluR1断裂的短肽神经保护剂显示出对SAH治疗的显著效果，具有很强的临床转化前景。本项目研究结果发表SCI论文7篇，其中中科院2分区以上4篇；中文核心论文2篇。本项目成果为治疗SAH后脑损伤提供新靶点：谷氨酸毒性—mGluR1。