内质网应激在甲基苯丙胺诱导的神经毒性中的作用及其分子病理机制

Methamphetamine (METH) is a highly addictive psychostimulant drug of abuse, causing addiction and serious damage to the vital organs, including the central nervous system. Previous researches on mechanism of METH-induced neurotoxicity show that excessive release of dopamine after METH entering to neuron can lead to oxidative stress. The research on oxidative, anti-oxidative and mitochondrial pathway is predominantly in the field of damage mechanism of oxidative stress induced by METH. However, the role of non-mitochondrial pathway involved in METH-induced neurotoxicity is still unknown. Our preliminary study, combined with previous studies, suggests that endoplasmic reticulum stress (ERS) may contribute to METH neurotoxicity. The present study will focus on a series of molecular pathological findings, such as cell injury, death and degeneration, which caused by ERS. The major research contents are to: ①Identify that METH can induce neurotoxicity by ERS; ②Clarify that the signaling pathway of P8-Chop-Trib3 play key roles in METH-induced neurotoxicity by ERS; ③Identify that phosphorylated Tau protein by activating through ERS and CDK5 is contributed to neuronal structure stableness and degeneration; ④Explore the mechanism underlying the neuronal plasticity caused by exposure to high dose of METH. ⑤Validate the results from animal experiments in postmortem human brains. The aims of this proposal are to provide new strategies and new methods for the protection of METH-induced neurotoxicity by investigating the role and mechanism of ERS.

甲基苯丙胺（METH）滥用者在成瘾同时，也严重损害机体重要脏器，尤其是中枢神经系统。既往对METH神经毒性机制研究发现，多巴胺过度释放可致神经元氧化应激损伤，目前对该损伤的研究主要集中在氧化、抗氧化及线粒体损伤相关分子机制,但对非线粒体损伤在METH致神经毒性中的作用尚不清楚。文献和我们前期预实验提示内质网应激可能参与METH神经毒性。本项目拟研究内质网应激主导的氧化应激致细胞损伤、死亡及退行性变等过程，进一步揭示METH神经毒性分子病理机制。内容包括：①METH激活内质网应激致神经毒性；②P8-Chop-Trib3信号轴在内质网致神经毒性中的作用；③METH通过CDK5和内质网应激致Tau蛋白磷酸化与神经元退行性变；④METH激活内质网应激致神经元树突重塑；⑤人类材料的相关发现验证。目的在于阐明内质网应激在METH致神经毒性中的作用及机制，为保护METH导致的神经损伤提供新策略和新方法。

甲基苯丙胺（METH）造成成瘾的同时，还会对人体重要器官造成器质性损害，特别是对大脑的毒性损害作用异常突出。既往研究发现主要认为，METH通过多巴胺过度释放引起神经元氧化应激损伤，但是具体机制并未阐明，而关于非线粒体损伤途径导致的氧化应激损伤机制研究更少。本项目通过细胞、动物及行为学实验等，验证了细胞器-内质网作为细胞发生氧化应激的重要场所，在METH神经毒性损伤中发挥重要作用。METH通过激活内质网应激，激活P8-Chop-Trib3信号通路，介导神经细胞发生自噬及凋亡。此外，还证实了C/EBPβ、PUMA、DDIT4、LCN2、RIP3、炎性介质多条氧化应激通路参与介导神经细胞凋亡自噬。在神经细胞结构改变方面，证实了CDK5通过p-Tau影响神经细胞骨架改变，多巴胺受体D1/D2、突触后致密蛋白PSD-95、突触间黏附分子NLG-1对神经结构重塑的影响。其中，LCN2、RIP3在尸检标本上得到了验证。METH除了对神经系统产生损害，对心血管系统的损害也值得关注。我们还证实了内质网应激相关通路P8-Chop/P53-PUMA/Beclin1信号轴、DDIT4分子除了在METH神经毒性损伤中发挥作用，也参与METH心血管毒性损伤机制。在成果转化方面，我们开发了一种温度敏感型水凝胶，能有效延长活化素B对帕金森症状的治疗作用时间，为开发延长缓解帕金森患者症状的药物研究提供重要依据。通过本项目的研究，丰富了MEHT毒性损伤机制的理论基础，为吸食METH死亡者的传统病理学及分子病理学诊断提供重要依据，为保护METH导致的神经及心血管毒性经损害预防思路提供新的策略。