Inhibition of biliverdin reductase increases ANG II-dependent superoxide levels in cultured renal tubular epithelial cells.
Inhibition of biliverdin reductase increases ANG II-dependent superoxide levels in cultured renal tubular epithelial cells.
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胆绿素还原酶的抑制会增加培养的肾小管上皮细胞中 ANG II 依赖性超氧化物水平。
DOI：
10.1152/ajpregu.90933.2008
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发表时间：
2009
期刊：
影响因子：
--
通讯作者：
Stec,DavidE
中科院分区：
文献类型：
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作者：
Young,ShelbyC;Storm,MeganV;Speed,JoshuaS;Kelsen,Silvia;Tiller,ChelseaV;Vera,Trinity;Drummond,HeatherA;Stec,DavidE
在肾髓质中诱导血红素加氧酶-1（HO-1）增加一氧化碳和胆红素的产生，并减少ANG II介导的超氧化物的产生。本研究的目的是确定胆红素增加的重要性，HO-1诱导的抗氧化作用，在培养的小鼠厚的汉勒升袢（TALH）和内髓集合管（IMCD 3）细胞。通过使用靶向胆绿素还原酶（BVR）的小干扰RNA（siRNA）降低胆红素水平，BVR是负责胆绿素转化为胆红素的细胞酶。用BVR siRNA（50或100 nM）处理培养的TALH或IMCD-3细胞，导致BVR蛋白水平降低80%，细胞胆红素水平从46 ± 5降低至23 ± 4 nM（n= 4）。然后，我们确定了抑制BVR对ANG II介导的超氧化物产生的影响。ANG II（10− 9 M）诱导的超氧化物生成在TALH和IMCD-3细胞中均显著增加。用BVR siRNA处理TALH细胞导致哇巴因敏感的铷摄取从对照的95 ± 6%显著增加至122 ± 5%（n= 4，P< 0.05）。最后，用siRNA抑制BVR并不能阻止在用HO-1诱导剂氯化血红素预处理的细胞中观察到的超氧化物水平的降低。我们的结论是，细胞胆红素水平的降低增加血管紧张素II介导的超氧化物生成和钠转运;然而，胆红素的增加是没有必要的HO-1诱导减弱血管紧张素II介导的超氧化物生成。
Induction of heme oxygenase-1 (HO-1) in the renal medulla increases carbon monoxide and bilirubin production and decreases ANG II-mediated superoxide production. The goal of this study was to determine the importance of increases in bilirubin to the antioxidant effects of HO-1 induction in cultured mouse thick ascending loop of Henle (TALH) and inner medullary collecting duct (IMCD3) cells. Bilirubin levels were decreased by using small interfering RNAs (siRNAs) targeted to biliverdin reductase (BVR), which is the cellular enzyme responsible for the conversion of biliverdin to bilirubin. Treatment of cultured TALH or IMCD-3 cells with BVR siRNA (50 or 100 nM) resulted in an 80% decrease in the level of BVR protein and decreased cellular bilirubin levels from 46 ± 5 to 23 ± 4 nM (n= 4). We then determined the effects of inhibition of BVR on ANG II-mediated superoxide production. Superoxide production induced by ANG II (10−9M) significantly increased in both TALH and IMCD-3 cells. Treatment of TALH cells with BVR siRNA resulted in a significant increase in ouabain-sensitive rubidium uptake from 95 ± 6 to 122 ± 5% control (n= 4,P< 0.05). Lastly, inhibition of BVR with siRNA did not prevent the decrease in superoxide levels observed in cells pretreated with the HO-1 inducer, hemin. We conclude that decreased levels of cellular bilirubin increase ANG II-mediated superoxide production and sodium transport; however, increases in bilirubin are not necessary for HO-1 induction to attenuate ANG II-mediated superoxide production.