Luo Muyun, Wang Zongqi, Wu Jie, Xie Xueshun, You Wanchun, Yu Zhengquan, Shen Haitao, Li Xiang, Li Haiying, Liu Yanfei, Wang Zhong, Chen Gang
Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou 215006, China; Institute of Stroke Research, Soochow University, Suzhou 215006, China; Department of Neurosurgery, The First Affiliated Hospital of Gannan Medical University, Gannan Medical University, Ganzhou 341000, China.
Department of Neurosurgery & Brain and Nerve Research Laboratory, The First Affiliated Hospital of Soochow University, Soochow University, Suzhou 215006, China; Institute of Stroke Research, Soochow University, Suzhou 215006, China.
Neuroscience. 2022 May 10;490:155-170. doi: 10.1016/j.neuroscience.2022.03.009. Epub 2022 Mar 16.
Intracerebral hemorrhage (ICH) is a hemorrhagic stroke with a high mortality and disability rate. Neurological impairment after ICH is closely associated with neuronal axon damage. Serine/threonine-protein kinase p21 activated kinase 1 (PAK1) participates in cytoskeletal remodeling and regulates the F-actin and G-actin ratio in neuronal axons, but the function of PAK1 after ICH remains unclear. We established an in vivo rat ICH model by autologous whole blood injection into the right basal ganglia and an in vitro neuron oxyhemoglobin intervention. The results showed that the phosphorylated PAK1 level increased while the PAK1 expression level unchanged after ICH, After PAK1 knockdown, PAK1 and phosphorylated PAK1 levels were both reduced. Meanwhile, downstream proteins LIMK1 and cofilin expression levels were unchanged while phosphorylated LIMK1 and phosphorylated cofilin were decreased. F-actin/G-actin ratio decreased after PAK1 knockdown. Moreover, PAK1 knockdown improved short- and long-term neurobehavioral impairments in rats. In vitro, phosphorylated PAK1 expression increased after oxyhemoglobin intervention. After PAK1 knockdown, the axon length of neurons increased while F-actin/G-actin ratio decreased. Spersman correlation analysis showed a negative correlation between phospho-PAK1 fluorescence intensity and neuronal axon length. Knockdown of PAK1 increased the live/dead cell ratio and promoted neurons survival. Our study showed that PAK1 is involved in ICH early secondary brain injury by affecting F-actin/G-actin ratio through the PAK1/LIMK1/cofilin pathway. PAK1 may be an essential target for early secondary brain injury intervention after ICH.
脑出血（ICH）是一种死亡率和致残率都很高的出血性中风。脑出血后的神经功能障碍与神经元轴突损伤密切相关。丝氨酸/苏氨酸蛋白激酶p21激活激酶1（PAK1）参与细胞骨架重塑，并调节神经元轴突中F-肌动蛋白和G-肌动蛋白的比例，但脑出血后PAK1的功能仍不清楚。我们通过向右侧基底神经节注射自体全血建立了大鼠脑出血体内模型，并进行了体外神经元氧合血红蛋白干预。结果显示，脑出血后磷酸化PAK1水平升高而PAK1表达水平不变，敲低PAK1后，PAK1和磷酸化PAK1水平均降低。同时，下游蛋白LIMK1和丝切蛋白的表达水平不变，而磷酸化LIMK1和磷酸化丝切蛋白减少。敲低PAK1后F-肌动蛋白/G-肌动蛋白比例降低。此外，敲低PAK1改善了大鼠的短期和长期神经行为障碍。在体外，氧合血红蛋白干预后磷酸化PAK1表达增加。敲低PAK1后，神经元轴突长度增加而F-肌动蛋白/G-肌动蛋白比例降低。斯皮尔曼相关性分析显示磷酸化PAK1荧光强度与神经元轴突长度呈负相关。敲低PAK1增加了活/死细胞比例并促进了神经元存活。我们的研究表明，PAK1通过PAK1/LIMK1/丝切蛋白途径影响F-肌动蛋白/G-肌动蛋白比例，参与脑出血早期继发性脑损伤。PAK1可能是脑出血后早期继发性脑损伤干预的重要靶点。
