【摘要】 目的:研究过氧化物酶体增殖物激活受体-α(PPAR-α)激活对内皮素-1(ET-1)诱导的心肌肥大和活化T细胞核因子c4(NFATc4)的影响,探讨在心肌肥大发病过程中PPAR-α和NFATc4的相互作用。方法:培养新生SD大鼠心肌细胞,采用[3H]亮氨酸法和RT-PCR法观察PPAR-α激动剂非诺贝特对ET-1诱导的心肌细胞肥大的影响;应用免疫荧光和免疫共沉淀技术分别检测非诺贝特对ET-1诱导的NFATc4核转位以及PPAR-α和NFATc4相互作用的影响;用Western blotting法检测NFATc4的胞浆和胞核表达。结果:(1)PPAR-α激动剂非诺贝特显著抑制ET-1诱导的肥厚反应。(2)非诺贝特阻止ET-1诱导NFATc4由胞浆到胞核的转位。(3)在心肌细胞中,PPAR-α和NFATc4之间存在相互作用,非诺贝特加强了这种相互作用。结论:PPAR-α激活后可以通过调控转录因子NFATc4来抑制ET-1诱导的心肌肥大反应。更多还原

【Abstract】 AIM: To investigate the effects of peroxisome proliferator-activated receptor-α(PPAR-α) activation on ET-1-induced cardiomyocyte hypertrophy and the interaction of PPAR-α with nuclear factor of activated T cell(NFAT)c4 in cardiac myocytes.METHODS: Cultured cardiac myocytes of neonatal SD rats were used to establish the experiment models. leucine incorporation assay was performed to examine protein synthesis while reverse transcription-polymerase chain reaction(RT-PCR) was applied to analyze the mRNA level of atrial natriuretic factor(ANF).Immunofluorescence and confocal microscopic assay were used to evaluate the effects of PPAR-α activator fenofibrate on the nuclear translocation of NFATc4.Immunoprecipitation was performed to examine the association of PPAR-α with NFATc4 in cardiomyocytes.Western blotting analysis was performed to investigate the cytoplasmic and nuclear protein levels of NFATc4.RESULTS:(1) ET-1 significantly increased incorporation of leucine(1.73±0.08 fold vs control,P<0.01) and the level of ANF mRNA(1.74±0.25 fold vs control,P<0.01).However,PPAR-α activator fenofibrate(10 μmol/L) significantly inhibited the ET-1-induced protein incorporation in cardiomyocytes(-31% at 5 μmol/L,-49% at 10 μmol/L) and the expression of ANF mRNA in these cells(1.10±0.17 fold of control).(2) ET-1 stimulation markedly changed the translocation of NFATc4 from the cytoplasm to the nucleus while fenofibrate prevented this effect of ET-1.(3) The interactions between PPAR-α and NFATc4 were constitutively detectable while fenofibrate further increased the interaction between NFATc4 and PPAR-α.CONCLUSION: Activation of PPAR-α prevents ET-1-induced cardiac myocyte hypertrophy through negative regulation of NFATc4,possibly via blocking the nuclear translocation of NFATc4 and increasing the interaction of PPAR-α and NFATc4.更多还原