整合素β8在星形胶质细胞氧糖剥夺后对TGF-β1的活化影响

Effect of integrin β8 on TGF-β1 activation in astrocytes with oxygen glucose deprivation

摘要:

目的 探讨在氧糖剥夺（OGD）后，星形胶质细胞中整合素β₈（β₈）的表达对转化生长因子-β1（TGF-β1）活化的影响。方法 体外培养星形胶质细胞，OGD模拟缺氧缺血。免疫细胞化学法检测β₈蛋白在星形胶质细胞中的表达及分布，Western blot定量检测OGD处理后复氧12 h、1 d及2 d 时β₈蛋白表达的变化。建立星形胶质细胞与荧光素酶报道细胞（TMLC）共培养体系，利用RNA干扰技术抑制星形胶质细胞β₈表达，观察β₈对TGF-β1活化的影响。结果 β₈主要分布于星形胶质细胞的胞浆和树突；星形胶质细胞中β₈蛋白表达在复氧后12 h即有增加，1 d时达高峰；星形胶质细胞与TMLC共培养体系在复氧后各时间点TGF-β1活性增高趋势与星形胶质细胞β₈表达趋势相似，抑制β₈表达后，TGF-β1活性在各时间点均显著降低。结论 新生鼠在缺血缺氧时，星形胶质细胞高表达的β₈对中枢神经系统中TGF-β1的活化起重要调控作用。

Abstract:

Objective To study the effect of β₈ expression on transforming growth factor β1(TGF-β1) activation in astrocytes with oxygen glucose deprivation (OGD). Methods Astrocytes were cultured and then subjected to OGD to generate hypoxia-ischemia (HI) model in vitro. Immunocytochemistry was used to detect the expression and distribution of β₈ in nomoxia cultured cells. β₈ protein expression was quantified by Western blot at 12 hours, 1 day and 2 days after OGD. Astrocytes and luciferase reporter cells (TMLC) were co-cultured. β₈ RNA interference system was established to specifically inhibit β₈ expression in cultured astrocytes. TGF-β1 activation was then detected in the co-culture system. Results β₈ was mainly located in the cytoplasm and neurites of astrocytes. OGD resulted in increase of β₈ protein expression at 12 hours after reoxygenation in astrocytes, which was peaked at 1 day after reoxygenation. TGF-β1 activation was in accordance with β₈ expression in astrocyte-TMLC co-culture system after reoxygenation. After the inhibition of β₈, TGF-β1 activation was significantly reduced in all time points. Conclusions The highly expressed β₈ plays important roles in the regulation of TGF-β1 activation in neonatal rats with hypoxic-ischemic brain damage.