Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, 101 Longmian Avenue, Nanjing, Jiangsu, 211166, China.
Department of Pharmacology, Nanjing University of Chinese Medicine, 138 Xianlin Avenue, Nanjing, Jiangsu, 210023, China.
Cell Death Differ. 2018 Nov;25(11):2037-2049. doi: 10.1038/s41418-018-0127-2. Epub 2018 May 21.
Astrocytes are involved in the neuroinflammation of neurodegenerative diseases, such as Parkinson's disease (PD). Among the numerous inflammatory cytokines, interleukin-1β (IL-1β) produced by astrocytic Nod-like receptor protein (NLRP) inflammasome is crucial in the pathogenesis of PD. β-arrestin2-mediated dopamine D2 receptor (Drd2) signal transduction has been regarded as a potential anti-inflammatory target. Our previous study revealed that astrocytic Drd2 suppresses neuroinflammation in the central nervous system. However, the role of Drd2 in astrocytic NLRP3 inflammasome activation and subsequent IL-1β production remains unclear. In the present study, we used 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine-induced PD mouse model to investigate whether Drd2 could suppress astrocytic NLRP3 inflammasome activation. We showed that Drd2 agonist inhibited NLRP3 inflammasome activation, evidenced by decreased caspase-1 expression and reduced IL-1β release in the midbrain of wild type mice. The anti-inflammasome effect of Drd2 was abolished in β-arrestin2 knockout and β-arrestin2 small interfering RNA-injected mice, suggesting a critical role of β-arrestin2 in Drd2-regulated NLRP3 inflammasome activation. We also found that Drd2 agonists suppressed the upregulation of caspase-1 and IL-1β expression in primary cultured mouse astrocytes in response to the activation of NLRP3 inflammasome induced by lipopolysaccharide plus adenosine triphosphate. Furthermore, we demonstrated that β-arrestin2 mediated the inhibitory effect of Drd2 on NLRP3 inflammasome activation via interacting with NLRP3 and interfering the inflammasome assembly. Collectively, our study illustrates that astrocytic Drd2 inhibits NLRP3 inflammasome activation through a β-arrestin2-dependent mechanism, and provides a new strategy for treatment of PD.
星形胶质细胞参与神经退行性疾病的神经炎症,如帕金森病(PD)。在众多炎症细胞因子中,星形胶质细胞 Nod 样受体蛋白(NLRP)炎症小体产生的白细胞介素-1β(IL-1β)在 PD 的发病机制中起关键作用。β-arrestin2 介导的多巴胺 D2 受体(Drd2)信号转导已被视为潜在的抗炎靶点。我们之前的研究表明,星形胶质细胞中的 Drd2 抑制中枢神经系统的神经炎症。然而,Drd2 在星形胶质细胞 NLRP3 炎症小体激活及随后的 IL-1β产生中的作用尚不清楚。在本研究中,我们使用 1-甲基-4-苯基-1,2,3,6-四氢吡啶诱导的 PD 小鼠模型来研究 Drd2 是否可以抑制星形胶质细胞 NLRP3 炎症小体的激活。我们发现,Drd2 激动剂抑制 NLRP3 炎症小体的激活,表现在野生型小鼠的中脑中 caspase-1 表达减少和 IL-1β释放减少。在β-arrestin2 敲除和β-arrestin2 小干扰 RNA 注射的小鼠中,Drd2 的抗炎小体作用被消除,表明β-arrestin2 在 Drd2 调节的 NLRP3 炎症小体激活中起关键作用。我们还发现,Drd2 激动剂抑制脂多糖加三磷酸腺苷诱导的 NLRP3 炎症小体激活后原代培养的小鼠星形胶质细胞中 caspase-1 和 IL-1β表达的上调。此外,我们证明β-arrestin2 通过与 NLRP3 相互作用并干扰炎症小体组装来介导 Drd2 对 NLRP3 炎症小体激活的抑制作用。总之,我们的研究表明,星形胶质细胞中的 Drd2 通过β-arrestin2 依赖的机制抑制 NLRP3 炎症小体的激活,并为 PD 的治疗提供了一种新策略。