δ阿片受体通过转激活表皮生长因子受体调节细胞自噬发挥抗脑卒中作用及其机制

δ opioid receptor (δOR) agonists are shown to induce neuroprotection and thereby reduce the death of neurons caused by ischemic stroke. However, the underlying mechanisms are not well known. Cells could digest and renew organelles by autophagy to reduce cells’ death. Our preliminary study found that δOR agonist could obviously improve the motor and sensory functions of rats suffered from brain ischemia and significantly reduce infarct area. β-arrestins were involved in the improvement of ischemic stroke by δOR agonist. Meanwhile, the epidermal growth factor receptor (EGFR) was activated in a time-dependent manner. Additionally, change in expression of the autophagy marker protein Beclin-1 and p62 was also observed. Since it has been shown that the downstream signaling of EGFR might promote autophagosome formation and induce protection effect via conformation of β-arrestins and Beclin-1 complex, thus, we hypothesized that activation of δOR might improve ischemic stroke by promoting the autophagosome formation through transactivating EGFR, recruiting β-arrestins to form complex with Beclin-1. To this end, we will use neuronal oxygen-glucose deprivation model and rat middle cerebral artery occlusion and reperfusion model, combining pharmacologic and genetic methods to investigate the molecular mechanisms by which δORs antagonize stroke by transactivation of EGFR, thereby regulating cellular autophagy.

δ阿片受体（δOR）激动剂具有神经保护作用，可减少缺血性脑卒中引起的细胞死亡，但机制研究尚不明确。细胞可通过自噬消化更新细胞器，减少细胞死亡。我们前期研究发现预先给予δOR激动剂，可明显改善脑缺血大鼠的运动和感觉功能障碍，明显缩小脑缺血区域面积，该作用有抑制蛋白β-arrestins参与。同时可见表皮生长因子受体（EGFR）呈时间依赖性的激活，及自噬标志蛋白Beclin-1和p62水平变化。文献提示EGFR下游信号可能通过招募β-arrestins与Beclin-1形成复合物，促使自噬体形成。据此我们提出假说：δOR转激活EGFR，招募β-arrestins与Beclin-1形成复合物，促进自噬体形成，减少细胞死亡，改善缺血性脑卒中。本项目将结合药理学和基因学手段，利用原代神经元氧糖剥夺模型和大鼠大脑中动脉栓塞再灌注模型，首次探讨δOR转激活EGFR调节自噬抗脑卒中的分子机制。

δ阿片受体（δOR）激动剂具有神经保护作用，可减少缺血性脑卒中引起的细胞死亡，但机制研究尚不明确。细胞可通过自噬消化更新细胞器，减少细胞死亡。我们前期研究发现预先给予δOR激动剂，可明显改善脑缺血大鼠的运动和感觉功能障碍，明显缩小脑缺血区域面积，该作用有抑制蛋白β-arrestins参与。同时可见表皮生长因子受体（EGFR）呈时间依赖性的激活，及自噬标志蛋白Beclin-1和p62水平变化。进一步研究中发现MCAO/R可导致β-arrestins与GAPDH发生了相互作用，而DADLE的预处理可减少其相互作用。该发现尚未见国内外报道。并且，研究发现MCAO/R引起的细胞凋亡，主要在背侧海马脑区，与血管内皮细胞共定位最多，多于神经元或胶质细胞，故分离原代脑微血管内皮细胞进行进一步的体内研究。根据结果，我们修正了科学假说：缺血性脑卒中发生后，δ阿片受体激动剂DADLE可通过缺氧缺血/再灌注损伤，减少细胞凋亡，其靶点位于脑微血管内皮细胞(BMECs)。具体机制涉及调节β-arrestins与GAPDH 相互作用，提高自噬水平，发挥抗脑卒中作用。本课题将有助于深入理解δOR激动剂改善生理状态下的缺血性脑卒中的药理机制，为开发新药提供药物靶点与治疗手段的新思路。