Retinoic acid receptor-related orphan receptor (ROR) α4 is the predominant isoform of the nuclear receptor RORα in the liver and is up-regulated by hypoxia in HepG2 human hepatoma cells
Retinoic acid receptor-related orphan receptor (ROR) α4 is the predominant isoform of the nuclear receptor RORα in the liver and is up-regulated by hypoxia in HepG2 human hepatoma cells
复制标题
DOI：
10.1042/bj20011558
复制
发表时间：
2002-06-01
影响因子：
4.1
通讯作者：
Danan, JL
中科院分区：
文献类型：
--
作者：
Chauvet, C;Bois-Joyeux, B;Danan, JL
视黄酸受体相关孤儿受体α（ROR α）与多个器官的许多生理功能密切相关。我们发现，在小鼠肝脏中的主要RORalpha亚型是RORalpha 4亚型，在mRNA和蛋白质水平，而RORalpha 1亚型是不太丰富。由于缺氧是肝脏生理和病理的主要特征，我们研究了这种应激对Rora基因表达和RORalpha转录活性的影响。将HepG 2人肝癌细胞在常氧（20%O-2）或缺氧（10、2和0.1%O-2）条件下培养24 h，并通过北方印迹和半定量RT-PCR测量Rora转录物的丰度。缺氧HcpG 2细胞中Rora mRNA的表达高于对照组。在原代培养的大鼠肝细胞中也观察到这一点。氯化钴和去铁胺也增加了HepG 2细胞中Rora mRNA的量。很可能这些处理增加了HepG 2细胞中RORalpha 4蛋白的量，如在去铁胺的情况下通过蛋白质印迹所证明的。瞬时转染实验表明，缺氧，氯化钴，去铁胺都刺激ROR α在HepG 2细胞的转录活性。因此，我们认为ROR α参与控制肝细胞中的基因转录，并调节基因表达以响应缺氧应激。
The retinoic acid receptor-related orphan receptor alpha (RORalpha) is critically involved in many physiological functions in several organs. We find that the main RORalpha isoform in the mouse liver is the RORalpha4 isoform, in terms of both mRNA and protein levels, while the RORalpha1 isoform is less abundant. Because hypoxia is a major feature of liver physiology and pathology, we examined the effect of this stress on Rora gene expression and RORalpha transcriptional activity. HepG2 human hepatoma cells were cultured for 24 h under normoxia (20 % O-2) or hypoxia (10, 2, and 0.1% O-2) and the abundance of the Rora transcripts measured by Northern blot and semi-quantitative RT-PCR. Hypoxic HcpG2 cells contained more Rora mRNA than controls. This was also observed in rat hepatocytes in primary culture. Cobalt chloride and desferrioxamine also increased the amount of Rora mRNA in HepG2 cells. It is likely that these treatments increase the amount of the RORalpha4 protein in HepG2 cells as evidenced by Western blotting in the case of desferrioxamine. Transient transfection experiments indicated that hypoxia, cobalt chloride, and desferrioxamine all stimulate RORalpha transcriptional activity in HepG2 cells. Hence, we believe that RORalpha participates in the control of gene transcription in hepatic cells and modulates gene expression in response to hypoxic stress.