Integrin CD11b mediates locus coeruleus noradrenergic neurodegeneration in a mouse Parkinson's disease model
Integrin CD11b mediates locus coeruleus noradrenergic neurodegeneration in a mouse Parkinson's disease model
复制标题
整合素 CD11b 介导小鼠帕金森病模型中蓝斑去甲肾上腺素能神经变性
DOI：
10.1186/s12974-020-01823-3
复制
发表时间：
2020-05-06
影响因子：
9.3
通讯作者：
Wang, Qingshan
中科院分区：
文献类型：
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作者：
Hou, Liyan;Qu, Xingyue;Wang, Qingshan
背景脑干蓝斑去甲肾上腺素能（LC/NE）神经元的缺失在包括帕金森病（PD）在内的多种神经退行性疾病中均有报道。然而，其机制仍不清楚。强有力的证据表明，小胶质细胞介导的神经炎症有助于PD的神经退行性变。我们最近认识到整合素CD 11b，巨噬细胞抗原复合物-1（Mac-1，也称为CR 3）的α链，是小胶质细胞活化的关键调节因子。然而，CD 11b是否参与PD LC/NE神经变性仍有待研究。方法采用CD 11b基因敲除（KO）小鼠和野生型（WT）小鼠，观察百草枯和代森锰钠对PD小鼠LC/NE神经元变性和小胶质细胞活化的影响。进一步探索NLRP 3炎性体在CD 11 b介导的小胶质细胞功能障碍和LC/NE神经变性中的作用。LC/NE神经变性，小胶质细胞表型，和NLRP 3炎性小体激活通过使用Western印迹，免疫组织化学和RT-PCR技术进行了测定。结果百草枯和代森锰联合染毒可增加小鼠脑干中CD 11b的表达，CD 11b基因敲除可明显减轻百草枯和代森锰联合染毒所致的LC/NE神经元变性。在百草枯和代森锰钠处理的CD 11b（-/-）小鼠中也观察到小胶质细胞活化和促炎细胞因子基因表达减轻。从机制上讲，CD 11b介导的NLRP 3炎性体激活有助于百草枯和代森锰诱导的LC/NE神经变性。与野生型对照组相比，CD 11b缺陷减少了百草枯和代森锰诱导的小鼠NLRP 3表达、caspase-1活化和白细胞介素-1 β产生。此外，发现格列本脲（一种NLRP 3炎性体的磺酰脲类抑制剂）对NLRP 3炎性体的抑制能够抑制百草枯和代森锰诱导的小胶质细胞促炎活化和核因子-κ B活化。此外，减少活性氧的产生，NADPH氧化酶，和表达，以及4-羟基壬烯醛和丙二醛水平检测在联合格列本脲和百草枯和代森锰钠治疗的小鼠与百草枯和代森锰钠单独组相比。最后，我们发现格列本脲治疗改善了百草枯和代森锰钠治疗小鼠的LC/NE神经变性和α-突触核蛋白聚集。结论CD 11b通过NLRP 3炎症依赖性小胶质细胞促炎激活介导了PD小鼠LC/NE神经元变性，为进一步研究LC/NE神经元损伤的免疫机制提供了新的思路。
Background The loss of locus coeruleus noradrenergic (LC/NE) neurons in the brainstem is reported in multiple neurodegenerative disorders, including Parkinson's disease (PD). However, the mechanisms remain unclear. Strong evidence suggested that microglia-mediated neuroinflammation contributes to neurodegeneration in PD. We recently recognized integrin CD11b, the alpha-chain of macrophage antigen complex-1 (Mac-1, also called CR3), as a key regulator for microglial activation. However, whether CD11b is involved in LC/NE neurodegeneration in PD remains to be investigated. Methods LC/NE neurodegeneration and microglial activation were compared between wild type (WT) and CD11b KO mice after treated with paraquat and maneb, two pesticides that widely used to create PD model. The role of NLRP3 inflammasome in CD11b-mediated microglial dysfunction and LC/NE neurodegeneration was further explored. LC/NE neurodegeneration, microglial phenotype, and NLRP3 inflammasome activation were determined by using Western blot, immunohistochemistry, and RT-PCR technologies. Results Paraquat and maneb co-exposure elevated the expressions of CD11b in the brainstem of mice, and CD11b knockout significantly reduced LC/NE neurodegeneration induced by paraquat and maneb. Mitigated microglial activation and gene expressions of proinflammatory cytokines were also observed in paraquat and maneb-treated CD11b(-/-) mice. Mechanistically, CD11b-mediated NLRP3 inflammasome activation contributes to paraquat and maneb-induced LC/NE neurodegeneration. Compared with WT controls, CD11b deficiency reduced paraquat and maneb-induced NLRP3 expression, caspase-1 activation, and interleukin-1 beta production in mice. Furthermore, inhibition of NLRP3 inflammasome by glybenclamide, a sulfonylurea inhibitor of NLRP3 inflammasome, was found to be able to suppress microglial proinflammatory activation and nuclear factor-kappa B activation induced by paraquat and maneb. Moreover, reduced reactive oxygen species production, NADPH oxidase, and expressions as well as 4-hydroxynonenal and malondialdehyde levels were detected in combined glybenclamide and paraquat and maneb-treated mice compared with paraquat and maneb alone group. Finally, we found that glybenclamide treatment ameliorated LC/NE neurodegeneration and alpha-synuclein aggregation in paraquat and maneb-treated mice. Conclusion Our findings suggested that CD11b mediates LC/NE neurodegeneration through NLRP3 inflammation-dependent microglial proinflammatory activation in a two pesticide-induced mouse PD model, providing a novel insight into the immune pathogenesis of LC/NE neuronal damage in related disorders.