尾加压素Ⅱ诱导心肌细胞肥大及对ERK/NF-κB通路的影响

Effects of Urotensin Ⅱ on Cardiomyocyte Hypertrophy and ERK/NF-κB Signaling Pathway

目的探讨尾加压素Ⅱ(UⅡ)对心肌细胞肥大及细胞外调节蛋白激酶/核转录因子-κB(ERK/NF-κB)通路的影响。方法培养1 d龄乳鼠心肌细胞,免疫荧光法测定心肌细胞体积,Lowry's法测定心肌细胞蛋白含量,[3H]-亮氨酸掺入法测定蛋白合成速率,免疫印记法测定NF-κB(p65)表达及其抑制物(I-κBα)磷酸化水平,凝胶电泳迁移率分析测定NF-κB体外活性,免疫沉淀法并ERK试剂盒测定ERK活性。结果与对照组比较,UⅡ能显著提高心肌细胞体积、细胞蛋白含量、蛋白合成速率;明显提高ERK活性,显著提高胞核NF-κB(p65)表达,提高细胞质I-κBα磷酸化,并显著上调NF-κB体外活性。结论 UⅡ可以诱导体外培养的乳鼠心肌细胞肥大,机制与上调ERK/NF-κB通路活性有关。

Objective To observe the effects of urotensin Ⅱ（UⅡ）on the cardiomyocytes hypertrophy and ERK/NF-κB signaling pathway. Methods The neonatal rat cardiomyocytes were cultured,and the cell size was assessed by immunofluorescence;total protein was determined by coomassie brilliant blue and protein synthesis rate was measured by -Leucine incorporation.ERK activity was measured by immuno-precipitation.The electrophoretic mobility shift assay（EMSA）was performed to detect the activity of NF-κB.The expression of NF-κB（p65）and p-I-κBα（NF-κB inhibitor）phosphorylation were assessed by using Western blot. Results Compared with the control,UⅡ enlarged the cell size,raised total protein and protein synthesis rate;increased the phosphorylation of I-κBα;upregulated activities of NF-κB and ERK,elicited p65 expression. Conclusion The hypertentrophic effect of UⅡ on cardiomyocyte hypertrophy was associated with enchancing the activity of ERK/NF-κB signaling pathway.