Expression of aminopeptidase A, an angiotensinase, in glomerular mesangial cells.
Expression of aminopeptidase A, an angiotensinase, in glomerular mesangial cells.
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氨肽酶 A（一种血管紧张素酶）在肾小球系膜细胞中的表达。
DOI：
10.1161/01.hyp.27.3.518
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发表时间：
1996
期刊：
影响因子：
--
通讯作者：
Healy,DP
中科院分区：
文献类型：
--
作者：
Troyanovskaya,M;Song,L;Jayaraman,G;Healy,DP
已知肾小球系膜细胞表达血管紧张素II 1型受体，并响应于循环和/或局部产生的血管紧张素II而收缩。此外，已知血管紧张素II水平升高刺激系膜细胞基质蛋白合成有助于肾小球硬化症的发展。以前，我们报道了肾小球系膜细胞免疫染色阳性，抗血清针对氨肽酶A，血管紧张素II代谢的主要血管紧张素酶。在这里，我们直接证明，氨肽酶A是在大鼠肾脏培养的系膜细胞表达。首先，培养的系膜细胞具有可测量的氨肽酶A酶活性。第二，免疫印迹氨肽酶A阳性分离肾小球和系膜细胞，虽然两个带被视为肾小球系膜细胞（138和144 kD），只有较大的带被视为分离肾小球和肾脏。第三，肾小球系膜细胞和肾脏总RNA的北方印迹杂交均为阳性，并标记出大小相似的条带。第四，系膜细胞总RNA的逆转录-聚合酶链反应扩增产生了预期大小的部分cDNA，通过测序证实其与大鼠肾氨肽酶A相同。这些结果表明氨肽酶A在系膜细胞内表达。这些结果进一步表明，氨肽酶A代谢血管紧张素II可以发挥保护作用，最大限度地减少血管紧张素II刺激系膜细胞的不良反应。
Glomerular mesangial cells are known to express angiotensin II type 1 receptors and contract in response to circulating and/or locally produced angiotensin II. In addition, stimulation of mesangial cell matrix protein synthesis by elevated levels of angiotensin II is known to contribute to the development of glomerulosclerosis. Previously, we reported that mesangial cells were positively immunostained with antiserum directed against aminopeptidase A, the principal angiotensinase in the metabolism of angiotensin II. Here we demonstrate directly that aminopeptidase A is expressed in mesangial cells cultured from rat kidney. First, cultured mesangial cells had measurable aminopeptidase A enzymatic activity. Second, immunoblots for aminopeptidase A were positive for isolated glomeruli and mesangial cells, although two bands were seen for mesangial cells (≈138 and 144 kD), and only the larger band was seen for isolated glomeruli and kidney. Third, Northern blot hybridizations of total RNA from mesangial cells or kidney were positive and labeled similarly sized bands. Fourth, reverse transcription–polymerase chain reaction amplification of mesangial cell total RNA yielded a partial cDNA of the expected size that was confirmed by sequencing to be identical to rat kidney aminopeptidase A. These results indicate that aminopeptidase A is expressed within mesangial cells. These results further suggest that metabolism of angiotensin II by aminopeptidase A could play a protective role in minimizing the adverse effects of angiotensin II stimulation of mesangial cells.