Effects of proinflammatory cytokines on rat organic anion transporters during toxic liver injury and cholestasis
Effects of proinflammatory cytokines on rat organic anion transporters during toxic liver injury and cholestasis
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DOI：
10.1053/jhep.2003.50317
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发表时间：
2003-08-01
期刊：
影响因子：
13.5
通讯作者：
Gartung, C
中科院分区：
文献类型：
--
作者：
Geier, A;Dietrich, CG;Gartung, C
在毒性和胆汁淤积性肝损伤中，肝胆转运蛋白下调。细胞因子如肿瘤坏死因子α（INF-α）和白细胞介素1 β（IL-1 β）被认为是介导这种调节的，但它们在体内的具体作用仍不清楚。因此，我们研究了肝损伤过程中促炎细胞因子调控Ntcp、Oatp 1、Oatp 2和Mrp 2的分子机制。大鼠腹腔注射四氯化碳或内毒素。分别通过反复腹腔注射依那西普和阿那白滞素实现TNF-α和IL-1 β的灭活。20至24小时后测定转运蛋白的信使RNA（mRNA）水平和结合活性以及Ntcp、Oatp 2和Mrp 2反式激活因子的核蛋白水平。与IL-1 β相反，TNF-α单独失活完全阻止了Ntcp、Oatp 1和Oatp 2 mRNA的下调，并降低了CCl 4诱导的毒性损伤中肝细胞核因子I（HNF-1）的结合活性。在内毒素血症中，Mrp 2的下调，部分在Ntcp的情况下，可以通过IL-1 β而不是TNF-α阻断来预防。然而，任一细胞因子的失活导致HNF 1和部分维甲酸X受体/视黄酸受体（RXR/RAR）结合活性的保留。未观察到抗细胞因子对雄烷X受体（PYR）和组成型雄烷受体（CAR）结合活性以及核蛋白质质量的影响。总之，TNF-α是CCl（4）（-）诱导的毒性肝损伤中Ntcp、Oatp 1和Oatp 2的HNF 1依赖性下调的主要细胞因子。IL-1 β在胆汁淤积性肝损伤的Ntcp和Mrp 2调节的复杂信号网络中占主导地位。与体外研究相反，HNF 1和RXR/RAR非依赖性机制似乎在内毒素血症中Mrp 2和Ntcp基因表达的调节中更重要。
Hepatobiliary transporters are down-regulated in toxic and cholestatic liver injury. Cytokines such as tumor necrosis factor alpha (INF-alpha) and interleukin 1beta (IL-1beta) are attributed to mediate this regulation, but their particular contribution in vivo is still unknown. Thus, we studied the molecular mechanisms by which Ntcp, Oatp 1, Oatp2, and Mrp2 are regulated by proinflammatory cytokines during liver injury. Rats were injected intraperitoneally with either carbon tetrachloride or endotoxin. Inactivation of TNF-alpha and IL-1beta was achieved by repetitive intraperitoneal injection of etanercept and anakinra, respectively. Messenger RNA (mRNA) levels of transporters and binding activities as well as nuclear protein levels of Ntcp, Oatp2, and Mrp2 transactivators were determined 20 to 24 hours later. In contrast to IL-1beta, TNF-alpha inactivation alone fully prevented down-regulation of Ntcp, Oatp1, and Oatp2 mRNA as well as reduced binding activity of hepatocyte nuclear factor I (HNF-1) in CCl4-induced toxic injury. In endotoxemia, down-regulation of Mrp2, and partially in case of Ntcp, could be prevented by IL-1beta but not TNF-alpha blockade. However, inactivation of either cytokine led to preservation of HNF1 and partially of retinoid X receptor/retinoic acid receptor (RXR/RAR) binding activity. No effect of anticytokines was seen on pregnane X receptor (PYR) and constitutive androstane receptor (CAR) binding activity as well as nuclear protein mass. In conclusion, TNF-alpha represents the master cytokine responsible for HNF1-dependent down-regulation of Ntcp, Oatp1, and Oatp2 in CCl(4)(-)induced toxic liver injury. IL-1beta predominates in a complex signaling network of Ntcp and Mrp2 regulation in cholestatic liver injury. In contrast to in vitro studies, HNF1 and RXR/RAR-independent mechanisms appear to be more important in regulation of Mrp2 and Ntcp gene expression in endotoxemia.