细胞内天然抗氧化活性物质还原型辅酶II神经保护作用的机制

Oxidative stress is one of commen mechanism in many neurological diseases, however, clinical application of anti-oxidants failed to generate satisfactory outcomes. Is the lack of clinical efficacy of antioxidants due to oxidative stress does not play a critical role in pathogenesis or due to the limitation of actions of antioxidants? It may have important theoretical and clinical significance to address this issue. Our previous studies found that a glucose metabolite via pentose phosphate pathway, NADPH had potent neuprotective effects. NADPH is a co-enzyme of glutathione reductase, assisting to produce reduced form of glutathione (rGSH) to reduce intracellular oxidative stress. The finding of neuroprotive effects of NADPH provides an opportinuty to re-evaluate neuroprotection of of anti-oxidants: are intracellular antioxidants novel neuroproctants? The aims of this project are: 1 to study the relationship of intracellular anti-oxidation activity of NADPH and rGSH; 2 to study the relationship of intracellular anti-oxidation activity of NADPH and mitochondrial function; 3 to study the relationship of intracellular anti-oxidation activity of NADPH and autophagy activity; 4 to compare the efficacy of neuroprotection of NADPH with a classical antoxidant edaravone. This study will uncover if reducing intracellular oxidative stress is an effective measure to protect neurons and if a new antioxidant which capable inhibiting intracellar oxidatiove stress has potential clinical values.

氧化应激是多种神经疾病的共同机制之一，但临床应用抗氧化剂鲜有取得满意疗效的。是氧化应激在神经疾病致病机制中不重要还是现有的抗氧化剂有局限性？解决这个问题具有重要理论和实际意义。我们的前期工作发现葡萄糖经戊糖旁路代谢产生的天然活性物质NADPH具有强大的神经保护作用。NADPH是细胞内谷胱甘肽还原酶的辅酶，协助生成还原型谷胱甘肽而发挥细胞内抗氧化作用。NADPH神经保护作用的发现提供了一个重新探讨抗氧化剂作用的机遇：即细胞内抗氧化剂能否是新型的神经保护剂？本项目旨在研究：1. NADPH细胞内抗氧化作用与还原型谷胱甘肽的关系；2. NADPH细胞内抗氧化与调节线粒体功能的关系；3.NADPH细胞内抗氧化与调节自噬的关系；4. NADPH与经典抗氧化剂依达拉奉神经保护作用的比较。此项目的研究成果将揭示细胞内抗氧化可能是保护神经元的有效措施，寻找发挥细胞内抗氧化作用的抗氧化剂具有临床应用价值。

项目组按照计划书内容开展研究工作。结果证实，NADPH可以通过改善能量代谢、ROS代谢，调节线粒体功能、自噬溶酶体信号通路，实现其在缺血性脑卒中、神经退行性疾病及神经炎症等疾病中的神经保护，并证实其较依达拉奉、丁苯酞等药物在缺血性脑卒中治疗中更具优势。此外，我们还延展了研究内容，其中非常重要的成果是发现了P2X7受体可以介导外源性NADPH进入细胞。通过分子对接、点突变等工作证明NADPH可作为P2X7受体的竞争性拮抗剂，阻断ATP对P2X7受体和小胶细胞炎症反应的激活，补充了NADPH在抗炎机制中除了抗氧化机制之外的新机制。这一发现也为阐明NADPH的药理作用提供了重要的靶点。我们还发现NADPH能通过提高FSP-1实现抑制脂质过氧化和铁死亡的作用，这一发现证实NADPH可能是一个新的铁死亡抑制剂。除了缺血性脑卒中，我们还进行了NADPH在心肌缺血治疗的研究，发现NADPH具有正性肌力作用，可通过激活P2Y11受体、活化SIRT3、增加ATP增加心肌收缩力，抑制由主动脉缩窄、异丙肾上腺素引起的心肌肥厚和心力衰竭，提示NADPH是一个潜在的新型强心剂。基于以上成果，项目组共发表基金标注SCI论文14篇，主持人作为主编出版英文学术专著《自噬-生物学与疾病》，获得1项发明专利。项目组已圆满且超额完成课题设计的研究内容和目标。