Department of Neurology, The Affiliated Huaian No. 1 People's Hospital of Nanjing Medical University, 1 Huanghe Road West, Huaian, 223300, Jiangsu, China.
Jiangsu Key Laboratory of Neurodegeneration, Department of Pharmacology, Nanjing Medical University, 101 Longmian Avenue, Nanjing, 211166, Jiangsu, China.
Mol Neurobiol. 2021 Apr;58(4):1303-1311. doi: 10.1007/s12035-020-02198-5. Epub 2020 Nov 9.
Recent researches showed that nucleotide-binding domain and leucine-rich repeat protein 3 (NLRP3) inflammasome inhibition exerted dopaminergic neuroprotection in cellular or animal models of Parkinson's disease (PD). NLRP3 inflammasome has been proposed as a drug target for treatment of PD. However, the interplay between chronic NLRP3 inflammasome and progressive α-synuclein pathology keeps poorly understood. Moreover, the potential mechanism keeps unknown. In the present study, we investigate whether NLRP3 inflammasome inhibition prevents α-synuclein pathology by relieving autophagy dysfunction in the chronic 1-methyl-4-phenyl-1, 2, 3, 6-tetrahydropyridine (MPTP) mouse model of PD. NLRP3 knockout mice and their wild-type counterparts were treated with continuous MPTP administration via osmotic mini-pumps. Dopaminergic neuronal degeneration was assessed by western blotting and immunohistochemistry (IHC). The levels of dopamine and its metabolites were determined using high-performance liquid chromatography. NLRP3 inflammasome activation and autophagy biomarkers were assessed by western blot. The expressions of pro-inflammatory cytokines were measured by ELISA. The glial reaction and α-synuclein pathology were assessed by IHC and immunofluorescence. Our results show that NLRP3 inflammasome inhibition via NLRP3 knockout not only protects against nigral dopaminergic degeneration and striatal dopamine deletion but also prevents nigral pathological α-synuclein formation in PD mice. Furthermore, it significantly suppresses MPTP-induced glial reaction accompanied by the secretion of pro-inflammatory cytokines in the midbrain of mice. Most importantly, it relieves autophagy dysfunction in the midbrain of PD mice. Collectively, we demonstrate for the first time that improving autophagy function is involved in the preventive effect of NLRP3 inflammasome inhibition on α-synuclein pathology in PD.
最近的研究表明，核苷酸结合域和富含亮氨酸重复蛋白 3（NLRP3）炎症小体抑制在帕金森病（PD）的细胞或动物模型中发挥多巴胺能神经保护作用。NLRP3 炎症小体已被提议作为治疗 PD 的药物靶点。然而，慢性 NLRP3 炎症小体与进行性α-突触核蛋白病理学之间的相互作用仍知之甚少。此外，潜在的机制尚不清楚。在本研究中，我们研究了 NLRP3 炎症小体抑制是否通过缓解慢性 1-甲基-4-苯基-1,2,3,6-四氢吡啶（MPTP）诱导的 PD 小鼠模型中的自噬功能障碍来预防α-突触核蛋白病理学。通过渗透微型泵连续给予 NLRP3 敲除小鼠及其野生型对照 MPTP 处理。通过 Western blot 和免疫组织化学（IHC）评估多巴胺能神经元变性。使用高效液相色谱法测定多巴胺及其代谢物的水平。通过 Western blot 评估 NLRP3 炎症小体激活和自噬生物标志物。通过 ELISA 测量促炎细胞因子的表达。通过 IHC 和免疫荧光评估神经胶质反应和α-突触核蛋白病理学。我们的结果表明，通过 NLRP3 敲除抑制 NLRP3 炎症小体不仅可以防止黑质多巴胺能变性和纹状体多巴胺缺失，还可以防止 PD 小鼠中黑质病理性α-突触核蛋白的形成。此外，它还显著抑制了 MPTP 诱导的小鼠中脑的神经胶质反应以及促炎细胞因子的分泌。最重要的是，它缓解了 PD 小鼠中脑的自噬功能障碍。总的来说，我们首次证明改善自噬功能参与了 NLRP3 炎症小体抑制对 PD 中α-突触核蛋白病理学的预防作用。
