MicroRNA-124对MEKK3蛋白表达调控在帕金森病炎性发病机制中的作用

Central nervous system’s chronic inflammation mediated by microglial cells plays critical roles in the PD’s pathological progression, and the activation of nuclear transcription factor NF-κB induced by caspase8/3 is the important pathway for microglial activation. Previously, we found that miR-124 can inhibite the activity of microglial cells through interfering with the caspase8/3’s activation, which could effectively relieve the apoptosis of substantia nigra neurons in PD animal models, but its mechanism still remains unclear. Bioinformatics software predicts that MEKK3 mRNA contains conserved binding sites of miR-124, and we have shown an initial proof that there was directly regulatory effect between them, additionally, MEKK3 is the key protein contributing the rapid and transient NF-κB activation. Based on the above, this project tries to verify the effects of miR-124 through a series of molecular and cell biology techniques, including inhibiting the expression of MEKK3 expression, interfering the activation of NF-κB and blocking the caspase signal transduction pathway, which prevents the activation of microglial cells; meanwhile verify the effects of miR-124 through PD animal and cell models, including inhibiting the activity of microglial cells to protect DA neurons, consequently slows down the PD’s pathological progression. This project will further improve the molecular biology and pathology of PD, and also provide new target and theoretical basis for biological intervention of PD.

小胶质细胞介导的中枢慢性炎症在帕金森病（PD）发生发展过程中起关键作用，且caspase8/3引发核转录因子NF-κB活化是小胶质细胞活化调控重要通路。前期我们发现miR-124可通过干扰caspase通路抑制小胶质细胞活性，缓解PD模型黑质区多巴胺神经元凋亡，但机制尚不明确。软件预测MEKK3 mRNA中存在miR-124保守结合位点，我们已初步证实miR-124可调控MEKK3表达，同时也引发NF-κB活性改变，而MEKK3是促进NF-κB快速活化关键蛋白。因此，本课题拟通过一系列分子/细胞生物学技术验证miR-124通过抑制MEKK3蛋白表达，干预NF-κB活化，中断caspase通路转导，从而阻止小胶质细胞活化；再通过PD细胞/动物模型验证miR-124通过抑制小胶质细胞活性保护多巴胺神经元，延缓疾病进展。本课题的完成将进一步完善PD分子学发病机制，也为PD治疗提供新靶点及理论依据

小胶质细胞介导的中枢慢性炎症在帕金森病（PD）发生发展过程中起关键作用，且核转录因子NF-κB活化是小胶质细胞活化的调控关键。本研究通过体外和体内实验发现（1）miR-124可抑制小胶质细胞的活性；（2）我们首次证实了miR-124可直接靶向MEKK3/NF-κB信号通路进而影响小胶质细胞的炎性反应；（3）在MPTP诱导的小鼠PD模型中，立体定向注射miR-124可抑制MEKK3、p-p65的表达及降低MPTP诱导的炎症反应，并能保护黑质多巴胺神经元的凋亡及死亡。成功得出“miR-124通过抑制MEKK3蛋白表达，干预NF-κB活化，从而阻止小胶质细胞活化、保护多巴胺神经元，延缓疾病进展”的结论，另外还额外证实了“ NEAT1 可与miR-124 发挥 ceRNA 调控作用且敲除 NEAT1可通过调控自噬反应影响小胶质细胞的活化”及“miR-124可以通过靶向p62/p38途径和自噬作用抑制PD神经炎症、延缓PD进展”等结论。丰富了现有的对PD致病的分子生物学机制认识，并为PD药物治疗提供新的靶点提供了重要参考。