Novel regulatory effect of angiotensin II type 1 receptor-interacting molecule on vascular smooth muscle cells
Novel regulatory effect of angiotensin II type 1 receptor-interacting molecule on vascular smooth muscle cells
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DOI：
10.1161/hypertensionaha.107.096115
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发表时间：
2007-11-01
期刊：
影响因子：
8.3
通讯作者：
Umemura, Satoshi
中科院分区：
文献类型：
--
作者：
Azuma, Koichi;Tamura, Kouichi;Umemura, Satoshi
我们最近克隆了一种与血管紧张素II 1型受体（AT1R）相关蛋白（ATRAP）相互作用的新型分子。在这项研究中，我们检验了ATRAP调节血管平滑肌细胞中血管紧张素II诱导的反应这一假设。免疫沉淀和生物发光共振能量转移分析的结果表明，在基线水平ATRAP和AT1R之间存在直接相互作用，并且显示血管紧张素II使这些蛋白质之间的相互作用增强了>2倍。免疫荧光分析的结果还表明，>65%的ATRAP与一种内体标记物组成性共定位。尽管在基线水平只有36%的ATRAP与AT1R共定位，但血管紧张素II增强了这些分子的共定位，并且在定量荧光分析中使92%的ATRAP与AT1R共定位。通过腺病毒转导过表达ATRAP使基线水平的细胞表面AT1R数量从4.33降至2.13飞摩尔/10⁶个细胞，并且即使在去除血管紧张素II后也从3.04降至1.26飞摩尔/10⁶个细胞。ATRAP还抑制了血管紧张素II介导的c - fos基因转录和转化生长因子 - β产生的增加。此外，这种抑制伴随着对血管紧张素II诱导的5 - 溴脱氧尿苷掺入激活的抑制。最后，通过小干扰RNA敲低ATRAP激活了血管紧张素II诱导的c - fos基因表达，而这种表达被一种AT1R特异性拮抗剂缬沙坦有效地抑制。这些结果表明，ATRAP促进AT1R的内化，并减弱血管紧张素II介导的c - fos - 转化生长因子 - β途径以及血管平滑肌细胞的增殖反应，这提示了一种通过新型且特异性阻断AT1R信号传导来抑制血管纤维化和重塑的新策略。
We have recently cloned a novel molecule that interacts with the angiotensin II type 1 receptor (AT1R)associated protein (ATRAP). In this study, we tested the hypothesis that ATRAP modulates angiotensin II-induced responses in vascular smooth muscle cells. The results of immunoprecipitation and bioluminescence resonance energy transfer assay demonstrated a direct interaction between ATRAP and AT1R at baseline and showed that angiotensin II enhanced the interaction of these proteins > 2-fold. The results of immunofluorescence analysis also demonstrated that > 65% of ATRAP constitutively colocalized with an endosome marker. Although only 36% of ATRAP colocalized with AT1R at baseline, angiotensin II enhanced the colocalization of these molecules and made 92% of ATRAP colocalize with AT1R on a quantitative fluorescence analysis. Overexpression of ATRAP by adenoviral transfer decreased the cell surface AT1R number from 4.33 to 2.13 fmol/10(6) cells at baseline and from 3.04 to 1.26 fmol/106 cells even after removal of angiotensin II. ATRAP also suppressed angiotensin II-mediated increases in c-fos gene transcription and transforming growth factor-beta production. Furthermore, this suppression was accompanied by inhibition of angiotensin II-induced activation of 5-bromodeoxyuridine incorporation. Finally, ATRAP knockdown by small-interference RNA activated angiotensin II-induced c-fos gene expression, which was effectively inhibited by valsartan, an AT1R-specific antagonist. These results indicate that ATRAP promotes internalization of AT1R and attenuates the angiotensin II-mediated c-fos-transforming growth factor-beta pathway and proliferative response in vascular smooth muscle cells, suggesting a novel strategy to inhibit vascular fibrosis and remodeling through a novel and specific blockade of AT1R signaling.