GRK5对大鼠星形胶质细胞活化的作用及其机制研究

目的:探讨培养新生大鼠皮层星形胶质细胞G蛋白偶联受体激酶5(GRK5)基因沉默后核因子κB(NF-κB)表达的变化及其与胶质细胞活化、炎症反应和氧化应激的关系。方法:采用分别或联合RNA干扰沉默GRK5基因表达与NF-κB抑制剂N-乙酰半胱氨酸干预进行实验分组。利用免疫荧光、实时定量PCR和Western blotting观察GFAP与活性caspase-3表达,细胞分泌TNF-α与NO的浓度,p65、TNF-α、IL-1β和iNOS的表达情况等。结果:GRK5 siRNA刺激星形胶质细胞活化,并检测到NF-κB表达增多(P0.01),TNF-α、IL-1β和iNOS mRNA表达水平增高(P0.01),细胞分泌TNF-α和NO增多(P0.01),活性caspase-3表达增多(P0.01)。采用GRK5 siRNA+NF-κB抑制剂联合干预可部分逆转GRK5 siRNA引起的上述变化(P0.05)。结论:GRK5基因沉默可能通过刺激NF-κB表达增多引起星形胶质细胞活化。GRK5的正常表达可能具有抑制星形胶质细胞活化相关炎症反应及氧化应激的作用。

Effect of GRK5 on activation of rat astrocytes

AIM: To study the effect of G-protein-coupled receptor kinase 5 (GRK5) on the activation of astrocytes in the brain cortex of newborn Wistar rats. METHODS: GRK5 gene was silenced in the model of rat brain cortex astrocytes in vitro for 24 h. N-acetylcysteine (NAC), which is a known inhibitor of NF-κB, was added into the culture medium according to gene silencing for 24 h. The expression levels of GFAP and caspase-3 were detected by the method of immunofluorescence, and the mRNA levels of NF-κB, TNF-α, IL-1β and iNOS were determined by real-time PCR. Moreover, the activity of SOD and concentrations of TNF-α and NO were measured. RESULTS: GRK5 gene silencing increased the expression of NF-κB at mRNA and protein levels obviously (P<0.01), and the mRNA levels of IL-1β and iNOS increased synchronously (P<0.01). Furthermore, caspase-3-positive cells in GRK5 siRNA group were increased compared with control siRNA group (P<0.01). Treatment with NAC obviously reduced the activity of NF-κB and weakened the effects induced by GRK5 siRNA (P<0.05). CONCLUSION: GRK5 siRNA increases NF-κB activity and induces the activation of astrocytes.