Aldosterone-induced EGFR expression: interaction between the human mineralocorticoid receptor and the human EGFR promoter
Aldosterone-induced EGFR expression: interaction between the human mineralocorticoid receptor and the human EGFR promoter
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DOI：
10.1152/ajpendo.00708.2006
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发表时间：
2007-06-01
影响因子：
5.1
通讯作者：
Gekle, Michael
中科院分区：
文献类型：
--
作者：
Grossmann, Claudia;Krug, Alexander W.;Gekle, Michael
醛固酮在心血管和肾损伤中起关键作用。其潜在机制尚未完全了解。由于表皮生长因子受体（EGFR）参与纤维化和血管功能障碍的发展，醛固酮结合的矿皮质激素受体（MR）上调EGFR的表达是一个有吸引力的假设。我们研究了醛固酮对肾上腺切除大鼠主动脉和原代培养人主动脉平滑肌细胞EGFR表达的影响。醛固酮而非地塞米松刺激了体内主动脉和HAoSMC中EGFR的表达。EGFR降解不受影响。醛固酮诱导的EGFR在HAoSMC中的表达呈剂量依赖性，螺内酯可阻止其表达。此外，与醛固酮孵育的HAoSMC导致EGF诱导的ERK1/ 2磷酸化增强和EGFR依赖性的介质纤维连接蛋白增加。EGFR启动子报告基因测定以及染色质免疫沉淀数据表明MR与EGFR启动子相互作用。通过缺失构建，我们获得证据表明这种相互作用发生在hMR和EGFR启动子区域316 - 163（较强的激活位点，EC50类似于1.0 nM）和163 - 1（较弱的激活位点，EC50类似于0.7 nM）之间，它们不包含典型的糖皮质激素反应元件，也不被人糖皮质激素受体激活。这种相互作用部分需要mr的nh2末端结构域，基于ELISA的转录因子DNA结合实验与体外合成的hMR显示直接结合163 - 1区。我们的研究结果表明，醛固酮通过与EGFR启动子的相互作用导致EGFR表达增强，这是MR特异性的，可能有助于醛固酮诱导纤维连接蛋白丰度的增加。
Aldosterone plays a key role in cardiovascular and renal injury. The underlying mechanisms are not completely understood. Because the epidermal growth factor receptor ( EGFR) is involved in the development of fibrosis and vascular dysfunction, upregulation of EGFR expression by aldosterone- bound mineralocorticoid receptor ( MR) is an attractive hypothesis. We investigated the effect of aldosterone on EGFR expression in the aorta of adrenalectomized rats and in human aorta smooth muscle cells ( HAoSMC) in primary culture. Aldosterone, but not dexamethasone, stimulated EGFR expression in vivo in the aorta as well as in HAoSMC. EGFR degradation was not affected. Aldosterone- induced EGFR expression in HAoSMC was dose dependent and prevented by spironolactone. Furthermore, incubation of HAoSMC with aldosterone led to enhanced EGF- induced ERK1/ 2 phosphorylation and an EGFR- dependent increase in media fibronectin. EGFR promoter reporter gene assay as well as chromatin immunoprecipitation data indicate that MR interacts with the EGFR promoter. With deletion constructs we gained evidence that this interaction takes place between the hMR and the EGFR promoter regions 316 - 163 ( stronger activation site, EC50 similar to 1.0 nM) and 163 - 1 ( weaker activation site, EC50 similar to 0.7 nM), which do not comprise canonical glucocorticoid response elements and are not activated by the human glucocorticoid receptor. The interactions require in part the NH2terminal domains of MR. ELISA- based transcription factor DNA binding assay with in vitro synthesized hMR suggest direct binding to region 163 - 1. Our results indicate that aldosterone leads to enhanced EGFR expression via an interaction with the EGFR promoter, which is MR specific and could contribute to the aldosterone- induced increase in fibronectin abundance.