Documentation of angiotensin II receptors in glomerular epithelial cells.
Documentation of angiotensin II receptors in glomerular epithelial cells.
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DOI：
10.1152/ajprenal.1998.274.3.f623
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发表时间：
1998-03
期刊：
影响因子：
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通讯作者：
Mukut Sharma;Ramratan Sharma;A. Greene;E. McCarthy;V. Savin
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文献类型：
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作者：
Mukut Sharma;Ramratan Sharma;A. Greene;E. McCarthy;V. Savin
血管紧张素II降低肾小球滤过率、肾血浆流量和肾小球毛细血管导水率。虽然血管紧张素II受体已被证明存在于肾小球系膜细胞和近端小管细胞，血管紧张素II受体在肾小球上皮细胞中的存在以前没有被证明。以前，我们已经报道，血管紧张素II引起的cAMP的积累和重组的肌动蛋白细胞骨架在培养的肾小球上皮细胞。目前的研究进行了验证血管紧张素II受体的存在下，通过免疫学和非肽受体配体结合技术，并确定激活细胞内信号转导的肾小球上皮细胞响应血管紧张素II。将肾小球上皮细胞的汇合单层培养物与血管紧张素II一起孵育，在培养基中有或没有氯沙坦和/或PD-123，319。通过均质化洗涤的细胞然后离心获得膜囊泡制备物。膜蛋白的十二烷基硫酸钠-聚丙烯酰胺凝胶电泳，然后进行多屏幕免疫印迹，以确定血管紧张素II受体1型（AT 1）或2型（AT 2）的存在。血管紧张素II介导的信号转导在肾小球上皮细胞通过测量cAMP的水平，使用放射免疫法进行了研究。在这些实验中获得的结果表明，在肾小球上皮细胞中存在AT 1和AT 2受体类型。发现血管紧张素II可导致cAMP在肾小球上皮细胞中蓄积，这只能通过同时使用氯沙坦和PD-123，319（分别为AT 1和AT 2的拮抗剂）来防止。AT 1和AT 2受体的存在和cAMP的增加表明肾小球上皮细胞对血管紧张素II的反应方式与系膜细胞或近端肾小管上皮细胞不同。我们的研究结果表明，肾小球上皮细胞参与血管紧张素II介导的肾小球滤过屏障的控制。
Angiotensin II decreases glomerular filtration rate, renal plasma flow, and glomerular capillary hydraulic conductivity. Although angiotensin II receptors have been demonstrated in mesangial cells and proximal tubule cells, the presence of angiotensin II receptors in glomerular epithelial cells has not previously been shown. Previously, we have reported that angiotensin II caused an accumulation of cAMP and a reorganization of the actin cytoskeleton in cultured glomerular epithelial cells. Current studies were conducted to verify the presence of angiotensin II receptors by immunological and non-peptide receptor ligand binding techniques and to ascertain the activation of intracellular signal transduction in glomerular epithelial cells in response to angiotensin II. Confluent monolayer cultures of glomerular epithelial cells were incubated with angiotensin II, with or without losartan and/or PD-123,319 in the medium. Membrane vesicle preparations were obtained by homogenization of washed cells followed by centrifugation. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis of membrane proteins followed by multiscreen immunoblotting was used to determine the presence of angiotensin II receptor type 1 (AT1) or type 2 (AT2). Angiotensin II-mediated signal transduction in glomerular epithelial cells was studied by measuring the levels of cAMP, using radioimmunoassay. Results obtained in these experiments showed the presence of both AT1 and AT2 receptor types in glomerular epithelial cells. Angiotensin II was found to cause an accumulation of cAMP in glomerular epithelial cells, which could be prevented only by simultaneous use of losartan and PD-123,319, antagonists for AT1 and AT2, respectively. The presence of both AT1 and AT2 receptors and an increase in cAMP indicate that glomerular epithelial cells respond to angiotensin II in a manner distinct from that of mesangial cells or proximal tubular epithelial cells. Our results suggest that glomerular epithelial cells participate in angiotensin II-mediated control of the glomerular filtration barrier.