Li Jiang, Deng Chun, Gu Wen-juan, Nie Sai, Peng Dao-quan, Zhao Shui-ping
Department of Cardiology, Central South University, Changsha, China.
Zhonghua Xin Xue Guan Bing Za Zhi. 2012 Feb;40(2):161-5.
To investigate the role of liver X receptors (LXRs) on endothelin-1 (ET-1) induced murine HL-1 cardiomyocytes hypertrophy.
Cultured murine HL-1 cardiomyocytes were divided into four experiment groups: (1) CONTROL GROUP:treated with DMSO; (2) T0901317 group:treated with LXRs agonist T0901317 (1 µmol/L); (3) ET-1 group:treated with ET-1 (1 nmol/L); (4) T0901317 + ET-1 group:treated with T0901317 (1 µmol/L) for 8 hours, then treated with ET-1 (1 nmol/L). Twenty-four hours later, immunofluorescent staining was performed on HL-1 cells, the surface area of HL-1 cells was analyzed with NIH Image J software, and the synthetic rate of protein in HL-1 cells was detected by (3)H-leucine incorporation. The mRNA level of atrial natriuretic peptide (ANP) and β-myosin heavy chain (β-MyHC) was measured by quantitative realtime PCR. The effect of T0901317 on mRNA expression of ANP was also detected after LXRs gene silencing.
The surface area of HL-1 cells, mRNA expression of ANP and β-MyHC, and (3)H-leucine incorporation in ET-1 group were 2.00 ± 0.29, 1.98 ± 0.47, 2.13 ± 0.39 and 1.79 ± 0.17, respectively, which were significantly higher than those of control group (1.00 ± 0.26, 1.00 ± 0.21, 1.00 ± 0.31 and 1.00 ± 0.03, respectively, all P < 0.05). Compared with ET-1 group, the surface area of HL-1 cells, mRNA expression of ANP and β-MyHC, and (3)H-leucine incorporation were significantly decreased in T0901317 + ET-1 group (1.24 ± 0.25, 1.19 ± 0.21, 1.48 ± 0.27 and 1.15 ± 0.11, respectively, all P < 0.05). After inhibition of LXRα/β expression in HL-1 cardiomyocytes using the specific siRNAs, the mRNA expression of ANP in T0901317 + ET-1 group was 1.78 ± 0.05, which was similar as that in ET-1 group (1.94 ± 0.17, P > 0.05).
T0901317, an agonist of LXRs, could inhibit ET-1 induced cardiac hypertrophy in vitro, and LXR ligand-mediated inhibition on ANP mRNA expression by T0901317 is receptor dependent.
研究肝脏X受体（LXRs）在内皮素-1（ET-1）诱导的小鼠HL-1心肌细胞肥大中的作用。
将培养的小鼠HL-1心肌细胞分为4个实验组：（1）对照组：用二甲基亚砜（DMSO）处理；（2）T0901317组：用LXRs激动剂T0901317（1 μmol/L）处理；（3）ET-1组：用ET-1（1 nmol/L）处理；（4）T0901317 + ET-1组：先用T0901317（1 μmol/L）处理8小时，然后用ET-1（1 nmol/L）处理。24小时后，对HL-1细胞进行免疫荧光染色，用NIH Image J软件分析HL-1细胞的表面积，通过³H-亮氨酸掺入法检测HL-1细胞中的蛋白质合成率。用定量实时聚合酶链反应检测心钠素（ANP）和β-肌球蛋白重链（β-MyHC）的mRNA水平。在LXRs基因沉默后，也检测了T0901317对ANP mRNA表达的影响。
ET-1组HL-1细胞的表面积、ANP和β-MyHC的mRNA表达以及³H-亮氨酸掺入率分别为2.00±0.29、1.98±0.47、2.13±0.39和1.79±0.17，均显著高于对照组（分别为1.00±0.26、1.00±0.21、1.00±0.31和1.00±0.03，均P<0.05）。与ET-1组相比，T0901317 + ET-1组HL-1细胞的表面积、ANP和β-MyHC的mRNA表达以及³H-亮氨酸掺入率均显著降低（分别为1.24±0.25、1.19±0.21、1.48±0.27和1.15±0.11，均P<0.05）。用特异性小干扰RNA（siRNAs）抑制HL-1心肌细胞中LXRα/β的表达后，T0901317 + ET-1组中ANP的mRNA表达为1.78±0.05，与ET-1组（1.94±0.17）相似（P>0.05）。
LXRs激动剂T0901317可在体外抑制ET-1诱导的心肌肥大，且T0901317通过LXR配体介导的对ANP mRNA表达的抑制作用是受体依赖性的。
