Beijing Institute of Brain Disorders, Laboratory of Brain Disorders, Ministry of Science and Technology, Collaborative Innovation Center for Brain Disorders, Capital Medical University, Beijing, China.
Cerebrovascular Disease Research Laboratory, Xuanwu Hospital, Beijing, China.
Stroke Vasc Neurol. 2021 Sep;6(3):344-351. doi: 10.1136/svn-2020-000490. Epub 2021 Jan 15.
The inflammatory response mediated by microglia/macrophages is closely related to cerebral ischaemia/reperfusion injury. Wild-type p53-induced protein phosphatase 1 (Wip1), a serine/threonine phosphatase, is expressed in various tissues. A growing number of reports have suggested that Wip1 is a negative regulator of inflammation in peripheral tissue; however, its role in the central nervous system (CNS) remains unclear. This study aimed to clarify whether Wip1 can inhibit CNS inflammation by regulating microglia/macrophage functions after ischaemic injury.
A model of middle cerebral artery occlusion and reperfusion was established in mice. CNS inflammation was simulated by lipopolysaccharide treatment of primary microglia. Laser speckle imaging was used to monitor regional cerebral blood flow. Behavioural outcomes were assessed with a TreadScan gait analysis system. TTC staining was used to evaluate the infarct volume, and western blotting and immunofluorescence staining were applied to detect the phenotypical transformation of microglia. ELISA was performed to detect the levels of inflammatory factors.
Wip1 expression was increased after ischaemia/reperfusion. Wip1-knockout (KO) mice displayed more severe brain injury than wild-type mice, as indicated by aggravated motor dysfunction, greater brain infarct volumes and higher expression of inflammatory cytokines (interleukin-6 and tumour necrosis factor alpha) in the brain. We also found that Wip1 depletion increased microglial/macrophage activation in both in vitro and in vivo models, which all showed activation of microglia/macrophages. Lentivirus- reversed the injury induced by Wip1-KO.
Our results suggest that Wip1 may inhibit neuroinflammation by inhibiting microglial/macrophage activation after brain ischaemia/reperfusion injury.
小胶质细胞/巨噬细胞介导的炎症反应与脑缺血/再灌注损伤密切相关。野生型 p53 诱导的蛋白磷酸酶 1（Wip1）是一种丝氨酸/苏氨酸磷酸酶，在各种组织中表达。越来越多的报道表明，Wip1 是外周组织炎症的负调节因子；然而，其在中枢神经系统（CNS）中的作用尚不清楚。本研究旨在阐明 Wip1 是否可以通过调节缺血损伤后小胶质细胞/巨噬细胞的功能来抑制 CNS 炎症。
建立小鼠大脑中动脉闭塞再灌注模型。用脂多糖处理原代小胶质细胞模拟 CNS 炎症。激光散斑成像用于监测局部脑血流。采用 TreadScan 步态分析系统评估行为学结果。TTC 染色评估梗死体积，Western blot 和免疫荧光染色检测小胶质细胞表型转化。ELISA 检测炎症因子水平。
缺血/再灌注后 Wip1 表达增加。Wip1 敲除（KO）小鼠比野生型小鼠表现出更严重的脑损伤，表现为运动功能障碍加重、脑梗死体积增大以及脑内炎症因子（白细胞介素-6 和肿瘤坏死因子-α）表达水平升高。我们还发现，Wip1 耗竭增加了体外和体内模型中小胶质细胞/巨噬细胞的激活，均显示小胶质细胞/巨噬细胞的激活。逆转录病毒逆转了 Wip1-KO 引起的损伤。
我们的结果表明，Wip1 可能通过抑制脑缺血/再灌注损伤后小胶质细胞/巨噬细胞的激活来抑制神经炎症。
