Heme oxygenase attenuates angiotensin II-mediated superoxide production in cultured mouse thick ascending loop of Henle cells.
Heme oxygenase attenuates angiotensin II-mediated superoxide production in cultured mouse thick ascending loop of Henle cells.
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DOI：
10.1152/ajprenal.00057.2008
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发表时间：
2008-10
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通讯作者：
Silvia Kelsen;B. Patel;Lawson B Parker;Trinity Vera;J. Rimoldi;R. Gadepalli;H. Drummond;D. Stec
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作者：
Silvia Kelsen;B. Patel;Lawson B Parker;Trinity Vera;J. Rimoldi;R. Gadepalli;H. Drummond;D. Stec
血红素加氧酶 (HO)-1 诱导可以减轻血管紧张素 II (ANG II) 依赖性高血压的发展。然而，HO-1降低血压的机制尚不清楚。本研究的目的是检验以下假设：HO-1 的诱导可以减少培养的粗升环 Henle (TALH) 细胞中 ANG II 介导的超氧化物产生的增加。对小鼠 TALH (mTALH) 细胞的永生化细胞系进行了研究。通过用钴原卟啉 (CoPP, 10 microM) 或氯高铁血红素 (50 microM) 处理或用含有人 HO-1 同工型的质粒转染，在培养的 mTALH 细胞中诱导 HO-1。用10(-9) M ANG II处理mTALH细胞可将二氢乙锭(DHE)荧光（超氧化物水平指数）从35.5+/-5增加到136+/-18相对荧光单位(RFU)/μm2。通过 CoPP、氯高铁血红素或人 HO-1 同种型的过表达诱导 HO-1，可将 ANG II 诱导的 DHE 荧光分别显着降低至 64+/-5、64+/-8 和 41+/-4 RFU/microm2。为了确定 HO-1 的哪种代谢物负责减少 ANG II 介导的 mTALH 细胞中超氧化物产生的增加，在暴露于 ANG II 之前，将细胞与胆红素或一氧化碳 (CO) 释放分子 (CORM)-A1（各为 100 µM）预孵育。与 ANG II 一起孵育后，DHE 荧光平均为 80+/-7 RFU/microm2，并在用胆红素和 CORM-A1 预处理后显着降低至 55+/-7 和 53+/-4 RFU/microm2。这些结果表明，mTALH 细胞中 HO-1 的诱导通过产生胆红素和 CO 来降低 ANG II 介导的超氧化物产生水平。
Heme oxygenase (HO)-1 induction can attenuate the development of angiotensin II (ANG II)-dependent hypertension. However, the mechanism by which HO-1 lowers blood pressure is not clear. The goal of this study was to test the hypothesis that induction of HO-1 can reduce the ANG II-mediated increase in superoxide production in cultured thick ascending loop of Henle (TALH) cells. Studies were performed on an immortalized cell line of mouse TALH (mTALH) cells. HO-1 was induced in cultured mTALH cells by treatment with cobalt protoporphyrin (CoPP, 10 microM) or hemin (50 microM) or by transfection with a plasmid containing the human HO-1 isoform. Treatment of mTALH cells with 10(-9) M ANG II increased dihydroethidium (DHE) fluorescence (an index of superoxide levels) from 35.5+/-5 to 136+/-18 relative fluorescence units (RFU)/microm2. Induction of HO-1 via CoPP, hemin, or overexpression of the human HO-1 isoform significantly reduced ANG II-induced DHE fluorescence to 64+/-5, 64+/-8, and 41+/-4 RFU/microm2, respectively. To determine which metabolite of HO-1 is responsible for reducing ANG II-mediated increases in superoxide production in mTALH cells, cells were preincubated with bilirubin or carbon monoxide (CO)-releasing molecule (CORM)-A1 (each at 100 microM) before exposure to ANG II. DHE fluorescence averaged 80+/-7 RFU/microm2 after incubation with ANG II and was significantly decreased to 55+/-7 and 53+/-4 RFU/microm2 after pretreatment with bilirubin and CORM-A1. These results demonstrate that induction of HO-1 in mTALH cells reduces the levels of ANG II-mediated superoxide production through the production of both bilirubin and CO.