Changes of Expression of Stretch-activated Potassium Channel TREK-1 mRNA and Protein in Hypertrophic Myocardium

Cardiac hypertrophyis an adaptive response tochronic pressure or volume stress.Pressure over-load-induced concentric hypertrophy is believed tohave a compensatory function through reducingwall stress and oxygen consumption.At the sameti me,ventricular hypertrophy is associated withsignificantlyincreased risk of heart failure and ma-lignant arrhythmia[1].During the progression ofventricular hypertrophy,stretch-activated potassi-umchannel plays ani mportant role in signal trans-duction between m…     

肿瘤坏死因子-α对THP-1巨噬细胞源性泡沫细胞ATP结合盒转运蛋白A1表达的影响

目的:观察肿瘤坏死因子-α(TNF-α)对THP-1巨噬细胞源性泡沫细胞ATP结合盒转运蛋白A1(ABCA1)表达的影响,同时探讨核因子-κB(NF-κB)在TNF-α调控ABC A1表达中的作用。方法:THP-1巨噬细胞源性泡沫细胞随机分为4组:对照组、TNF-α组、甲苯磺酰苯丙氨酰氯甲酮(TPCK,NF-κB的抑制剂)组、TPCK TNF-α组。运用逆转录聚合酶链反应(RT-PCR)和W estern b lot检测各组不同的时间点(0、6、12、24和48 h)ABCA1 mRNA和ABCA1蛋白的表达。结果:对照组和TPCK组ABCA1mRNA和蛋白表达均无明显变化;TNF-α组ABCA1mRNA和蛋白表达呈时间依赖性降低(P<0.05);TPCK TNF-α组ABCA1mRNA和蛋白表达也呈时间依赖性降低,但同TNF-α组比较,其下降程度有明显减轻(P<0.05)。结论:TNF-α可以通过活化NF-κB抑制THP-1巨噬细胞源性泡沫细胞ABCA1的表达。     

血管紧张素Ⅱ对THP-1源性泡沫细胞ATP结合盒转运子A1的影响

目的： 以THP-1源性泡沫细胞为研究对象，探讨血管紧张素Ⅱ（AngⅡ）对THP-1源性泡沫细胞ATP结合盒转运子A1(ABCA1)表达、细胞内胆固醇含量及胆固醇流出的影响。方法: 运用逆转录-多聚酶链反应（RT-PCR）和Western blotting分别检测AngⅡ对ABCA1 mRNA与ABCA1蛋白表达的影响，采用酶法，通过荧光分光光度计检测细胞内胆固醇含量，应用液体闪烁计数仪检测胆固醇流出的变化。结果: AngⅡ能引起THP-1源性泡沫细胞胆固醇含量显著升高(P<0.05)、ABCA1表达显著减少（P<0.05），AngⅡ受体拮抗剂厄贝沙坦（Irb）能显著减少细胞内胆固醇含量(P<0.05)、促进细胞内胆固醇流出及减轻AngⅡ对ABCA1的抑制作用(P<0.05)。结论: AngⅡ有通过其受体抑制ABCA1表达，促进泡沫细胞形成，加速动脉粥样硬化的作用。     

核因子κB活化与THP-1巨噬细胞源性泡沫细胞ABCA1表达的关系

目的：探讨核因子κB活化对THP-1巨噬细胞源性泡沫细胞ATP结合盒转运子A1（ABCA1）基因表达的影响。方法：体外培养THP-1细胞并构建泡沫细胞模型，使用肿瘤坏死因子α（TNF-α）和NF-κB活化抑制剂对甲苯磺酰-L-苯丙氨酸甲基甲酮（N-α-tosyl-L-phenylalanine chloromethy ketone，TPCK）孵育细胞，以RT-PCR法和Western blot法测定THP-1源性泡沫细胞ABCA1 mRNA和蛋白表达情况，借助Sandwich ELISA法观察核因子κB活化／核易位情况。结果：TNF-α可即刻激活NF-κB，并导致干预24小时后泡沫细胞ABCA1 mRNA和蛋白表达下调；若预先用TPCK孵育，则TPCK可抑制TNF-α对NF-κB的激活，且24小时后泡沫细胞ABCA1 mRNA和蛋白表达下调幅度减小；TPCK延迟孵育则对TNF-α的效应抑制不显著。结论：炎症因子TNF-α可即刻激活NF-κB信号途径，早期活化的NF-κB可阻遏THP-1源泡沫细胞ABCA1基因和蛋白的表达，影响泡沫细胞内胆固醇的流出。     

NF-κB在AngⅡ介导THP-1巨噬细胞源性泡沫细胞胆固醇流出及ABCA1表达调控过程中的作用研究

目的：探讨核因子NF-κB活化对AngⅡ诱导的THP-1巨噬细胞源性泡沫细胞ABCA1基因表达、胆固醇含量的影响。方法：体外培养THP-1细胞以构建泡沫细胞模型，以AngⅡ和NF-κB活化抑制剂TPCK孵育细胞；以RT-PCR法、Western blot法测定THP-1源泡沫细胞ABCA1 mRNA和蛋白表达状态；采用酶法，通过荧光分光光度计检测细胞内胆固醇含量，应用液体闪烁技术仪检测胆固醇流出的变化；借助Sandwich ELISA法测定核因子NF-κB活化／核易位情况。结果：AngⅡ可即刻激活NF-κB表达活性，并导致干预24小时后泡沫细胞ABCA1 mRNA和蛋白表达下调；若预先用TPCK孵育，则TPCK可抑制AngⅡ对NF-κB的激活，且24小时后泡沫细胞ABCA1 mRNA和蛋白表达下调幅度减小。结论：AngⅡ能引起THP-1源性泡沫细胞胆固醇含量显著增高（P〈0．05）、ABCA1表达显著减少（P〈0．05）。机制可能与AngⅡ即刻激活NF-κB信号途径，早期活化的NF-κB可阻遏THP-1源泡沫细胞ABCA1基因和蛋白的表达，继而影响泡沫细胞内胆固醇的流出有关。     

肺炎衣原体通过上调酰基辅酶A:胆固醇酰基转移酶1诱导人单核细胞株THP-1源性泡沫细胞形成的实验研究

Objective To investigate the expression changes of acyl-coenzyme A: cholesterol acyhransferase 1 (ACAT1) on Chlamydia pneumoniae (C. pn) induced foam cell formation. Methods Human monocytic cell line (THP-1) was induced into macrophages by 160 nmol/L phorbol myristate acetate (PMA)for 48 h, and were randomly allocated into four groups: negative control group (50 μg/ml LDL for 48 h) ; positive control group (50 μg/ml ox-LDL for48 h) ; C. pn infection group (50 μg/ml LDL plus 1× 105,4×105,5×105and 1×106 IFU C.pn for 48 h or 1×106 IFU C.pn for 0,24,48 and 72h); ACAT inhibitor 58-035 plus C. pn infection group (1, 5, 10 μg/ml ACAT inhibitor 58-035 pretreatment for 1 h,50 μg/ml LDL and 1 × 106 IFU C. pn for 48 h). The mRNA and protein expressions of ACATI were determined by RT-PCR and Western blot, respectively. Lipid droplets in cytoplasm were observed by oil red 0 staining. The contents of intracellular cholesteryl esters were detected by enzyme-fluorescence. Results The mRNA and protein expressions of ACATI were significantly up-regulated in positive control cells compared those in negative control cells and further upregulated by C. pn infection in a time-dependent and concentration-dependent manner (all P ＜ 0.05). There were significantly increases in the accumulation of lipid droplets and the ratio of cholesteryl ester to total cholesterol in positive control cells as compared with negative control cells and these were further aggravated by C. pn (at the concentrations of 5× 105 and 1×106IFU for 48 h) and C. pn infection induced increases in the accumulation of lipid droplets and the ratio of cholesteryl ester to total cholesterol could he significantly attenuated by ACAT inhibitor 58-035 (all P ＜ 0.05). Conclusion Chlamydia pneumoniae induces THP-1-derived foam cell formation by up-regulating the expression of ACATI.