低氧预处理激活神经元细胞JAK/STAT并促进血管内皮生长因子受体-2的表达  

Hypoxia preconditioning activates JAK/STAT signaling and promotes vascular endothelial growth factor receptor-2 expression in neurons

作　　者：韦可聪[1] 朱云中[1] 梁韡斌 张高炼[1] 

机构地区：[1]广西中医药大学第一附属医院神经外科,530023

出　　处：《中国神经免疫学和神经病学杂志》2015年第1期40-45,共6页Chinese Journal of Neuroimmunology and Neurology

摘　　要：目的研究低氧预处理对神经元细胞Janus激酶(JAK)/信号转导和转录激活因子(STAT)信号通路以及血管内皮生长因子受体-2(VEGFR-2)表达的影响。方法将培养的小鼠神经元细胞分为细胞对照组、细胞类缺血组和细胞低氧预处理组,细胞类缺血组细胞经95%NO2+5%CO2混合气体处理30min,细胞低氧预处理组细胞于89%N2、l%O2和10%CO2环境中处理8次,每次20min,2d后进行类缺血处理。定量分析各组细胞中VEGFR-2、JAK及STAT蛋白磷酸化(p-STAT)的表达变化。细胞转染JAK特异性小干扰RNA(siRNA),之后进行低氧预处理和类缺血处理,检测p-STAT和VEGFR-2的表达。另取45只BALB/c小鼠分为动物对照组(n=8)、动物对照+血管内皮生长因子(VEGF)组(n=7)、动物脑缺血组(n=8)、动物脑缺血+VEGF组(n=7)、动物低氧预处理组(n=8)和动物低氧预处理+VEGF组(n=7),分析各组海马神经元细胞pSTAT和VEGFR-2的表达,并检测细胞中含半胱氨酸的天冬氨酸蛋白水解酶(caspase 3)的活化情况。结果与细胞对照组相比较,细胞类缺血组细胞中VEGFR-2mRNA表达显著下调(P<0.05);与细胞类缺血组相比,细胞低氧预处理组细胞VEGFR-2mRNA表达上调(P<0.05),并促进JAK mRNA和蛋白的表达(P<0.05)以及STAT蛋白的活化(P<0.05)。与非特异性转染组相比,JAK沉默组细胞p-STAT和VEGFR-2的表达显著降低(均P<0.05)。在小鼠体内,脑缺血降低p-STAT和VEGFR-2的表达(P<0.05),而低氧预处理则可有效逆转缺氧对p-STAT和VEGFR-2的抑制(P<0.05)。与动物脑缺血+VEGF组相比,动物低氧预处理+VEGF干预可显著抑制caspase3的活化(P<0.05)。结论低氧预处理可以激活神经元细胞JAK/STAT信号通路并诱导VEGFR-2的表达,并增强VEGF的神经保护作用。Objective To investigate the effect of hypoxia preconditioning on JAK/STAT signaling and vascular endothelial growth factor receptor-2（VEGFR-2）expression of neurons.Methods Cultured mouse primary neurons were divided into control,ischemia and hypoxia preconditioning group.Neurons in ischemia group were treated with 95% NO2＋5% CO2 for 30 min and cells in hypoxia preconditioning group pretreated with 89%N2,l%O2and 10%CO2for 8times,each for 20 min,followed by ischemia treatment.At the end of the treatment,VEGFR-2mRNA and protein expressions as well as the expression of JAK and phosphorylated STAT（p-STAT）in neurons were analyzed.Moreover,neurons were transfected with JAK specific siRNA prior to hypoxia preconditioning and ischemia treatment.Then,p-STAT and VEGFR-2expressions were analyzed.Furthermore,forty-five BALB/c mice were randomized into control（n=8）,control＋VEGF（n=7）,ischemia（n=8）,ischemia＋VEGF（n=7）,hypoxia preconditioning（n=8）,hypoxia preconditioning＋VEGF groups（n=7）.After the treatment,neurons in hippocampus were separated for the analysis of p-STAT and VEGFR-2expressions along with the activation of caspase 3protein.Results Compared with the control,the expressions of VEGFR-2mRNA were markedly downregulated（P〈0.05）by ischemia.Compared with the ischemic group,hypoxia preconditioning significantly elevated the expressions of VEGFR-2mRNA,JAK mRNA and protein,and the phosphorylation of STAT.Compared with nonspecific siRNA group,knockdown of JAK inhibited the levels of p-STAT and VEGFR-2expression.In mouse models,ischemia significantly downregulated the expressions of p-STAT and VEGFR-2,which were reversed by hypoxia preconditioning.Compared with ischemia＋ VEGF group,hypoxia preconditioning＋VEGF remarkably inhibited the activation of caspase 3.Conclusions Hypoxia preconditioning might activate JAK/STAT and induce VEGFR-2 expressions,leading to enhancement of neuroprotection induced by VEGF in neurons after ischemia treatment.

关 键 词：缺氧 脑 缺血预处理 细胞内信号肽和蛋白质类 Janus激酶类 JAK/STAT 血管内皮生长因子受体-2 

分 类 号：R743.3[医药卫生—神经病学与精神病学]