转化生长因子β1对系膜细胞纤溶酶原激活物抑制物1表达的影响

Effect of TGF-a1 on plasminogen activator inhibitor-1 expression in rat glomerular mesangial cells

目的观察转化生长因子(TGF)β1对肾小球系膜细胞(GMC)纤溶酶原激活物抑制物(PAI)-1表达的影响,并探讨反应性氧基(ROS)在TGF-β1诱导的PAI-1表达中的作用。方法体外培养大鼠GMC,分别用TGF-β1(2ng/ml)和葡萄糖氧化酶(GO)(10mU/ml)刺激,并用BSO和抗氧化剂N-乙酰半胱氨酸(NAC)进行干预处理。采用Western印迹检测PAI-1蛋白表达;RT-PCR和Northern杂交检测PAI-1mRNA表达;合成的荧光素纤溶酶底物测定纤溶酶活性。结果外源性TGF-β1和GO可显著上调大鼠系膜细胞PAI-1蛋白和mRNA的表达并降低纤溶酶活性。BSO可显著增强TGF-β1和GO诱导的系膜细胞PAI-1mRNA的表达;而NAC可显著地逆转由TGF-β1和GO诱导的PAI-1mRNA表达的上调作用。结论TGF-β1可显著上调系膜细胞PAI-1的表达并抑制纤溶酶活性。ROS在TGF-β1诱导的系膜细胞PAI-1表达上调的信号传递途径中可能起了信号传递分子的作用。

Objective To investigate TGF-a1 regulating PAI-1 expression i n glomerular mesangial cells and to examine the role of reactive oxygen species(RO S) in signaling pathway of TGF-a1-induced PAI-1 expression. Methods Growth a rrested and synchronized rat mesangial cells were stimulated by TGF-a1(2 ng/m l)or glucose oxidase(GO)(10 mU/ml),respectively.The mesangial cells were pret reated with DL-bathionine-(S,R)-sulfoximine(BSO) or with antioxidant N-acet ylcysteine(NAC). PAI-1 protein secretion by mesangial cells was measured by Wes tern blot and PAI-1 mRNA by both RT-PCR and Northern blot. Plasmin activity wa s determined by using a synthetic fluorometric plasmin substrate. Results Exogen ous TGF-a1 and GO significantly upregulated PAI-1 mRNA and protein expression in mesangial cells and reduced the activity of plasmin. TGF-a1-and GO-induc ed upregulation of PAI-1 mRNA and protein expression was exaggerated by BSO.NAC effectively reversed TGF-a1-and GO-induced PAI-1 mRNA and protein overexpr ession. Conclusions TGF-a1 significantly upregulates the PAI-1 expression in mesangial cells and reduces the activity of plasmin. ROS acts as a mediator in s ignaling pathway of TGF-a1-induced PAI-1 overexpression.