Harry S. Truman Memorial Veterans Hospital, U.S. Department of Veterans Affairs, Columbia, MO, USA.
Department of Neurology, and the Center for Translational Neuroscience, School of Medicine, University of Missouri, Columbia, MO, USA.
J Alzheimers Dis. 2018;66(3):1117-1129. doi: 10.3233/JAD-180786.
Parkinson's disease (PD) is characterized by the presence of inflammation-mediated dopaminergic neurodegeneration in the substantia nigra. Inflammatory mediators from activated microglia, astrocytes, neurons, T-cells and mast cells mediate neuroinflammation and neurodegeneration. Administration of neurotoxin 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induces PD like motor deficits in rodents. 1-methyl-4-phenylpyridinium (MPP+), a toxic metabolite of MPTP activates glial cells, neurons and mast cells to release neuroinflammatory mediators. Glia maturation factor (GMF), mast cells and proteinase activated receptor-2 (PAR-2) are implicated in neuroinflammation. Alpha-synuclein which induces neurodegeneration increases PAR-2 expression in the brain. However, the exact mechanisms are not yet understood. In this study, we quantified inflammatory mediators in the brains of MPTP-administered wild type (Wt), GMF-knockout (GMF-KO), and mast cell knockout (MC-KO) mice. Additionally, we analyzed the effect of MPP+, GMF, and mast cell proteases on PAR-2 expression in astrocytes and neurons in vitro. Results show that the levels of interleukin-1beta (IL-1β), tumor necrosis factor-alpha (TNF-α), and the chemokine (C-C motif) ligand 2 (CCL2) were lesser in the brains of GMF-KO mice and MC-KO mice when compared to Wt mice brain after MPTP administration. Incubation of astrocytes and neurons with MPP+, GMF, and mouse mast cell protease-6 (MMCP-6) and MMCP-7 increased the expression of PAR-2. Our studies show that the absence of mast cells and GMF reduce the expression of neuroinflammatory mediators in the brain. We conclude that GMF along with mast cell interactions with glial cells and neurons during neuroinflammation can be explored as a new therapeutic target for PD and other neuroinflammatory disorders.
帕金森病(PD)的特征是黑质中存在炎症介导的多巴胺能神经退行性变。激活的小胶质细胞、星形胶质细胞、神经元、T 细胞和肥大细胞中的炎症介质介导神经炎症和神经退行性变。神经毒素 1-甲基-4-苯基-1,2,3,6-四氢吡啶(MPTP)给药会在啮齿动物中诱导出类似于 PD 的运动缺陷。MPTP 的毒性代谢物 1-甲基-4-苯基吡啶(MPP+)激活胶质细胞、神经元和肥大细胞释放神经炎症介质。胶质细胞成熟因子(GMF)、肥大细胞和蛋白酶激活受体 2(PAR-2)参与神经炎症。诱导神经退行性变的α-突触核蛋白会增加大脑中 PAR-2 的表达。然而,确切的机制尚不清楚。在这项研究中,我们定量分析了 MPTP 给药的野生型(Wt)、GMF 敲除(GMF-KO)和肥大细胞敲除(MC-KO)小鼠大脑中的炎症介质。此外,我们分析了 MPP+、GMF 和肥大细胞蛋白酶对体外星形胶质细胞和神经元中 PAR-2 表达的影响。结果表明,与 Wt 小鼠大脑相比,MPTP 给药后 GMF-KO 小鼠和 MC-KO 小鼠大脑中的白细胞介素-1β(IL-1β)、肿瘤坏死因子-α(TNF-α)和趋化因子(C-C 基序)配体 2(CCL2)水平较低。用 MPP+、GMF 和小鼠肥大细胞蛋白酶-6(MMCP-6)和 MMCP-7 孵育星形胶质细胞和神经元会增加 PAR-2 的表达。我们的研究表明,肥大细胞和 GMF 的缺失会降低大脑中神经炎症介质的表达。我们得出的结论是,GMF 以及肥大细胞与神经炎症期间的神经胶质细胞和神经元的相互作用可以作为 PD 和其他神经炎症性疾病的新治疗靶点进行探索。