Angiotensin II (AT1) receptors and NADPH oxidase regulate Cl- current elicited by beta1 integrin stretch in rabbit ventricular myocytes.
Angiotensin II (AT1) receptors and NADPH oxidase regulate Cl- current elicited by beta1 integrin stretch in rabbit ventricular myocytes.
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DOI：
10.1085/jgp.200409040
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发表时间：
2004-09
期刊：
影响因子：
--
通讯作者：
Baumgarten CM
中科院分区：
文献类型：
--
作者：
Browe DM;Baumgarten CM
β1整合素的直接拉伸通过黏附激酶（FAK）和/或Src激活向外整流，他莫昔芬敏感的Cl -电流（Cl - SAC）。Cl - SAC的特性类似于体积敏感的Cl -电流、ICl、膨胀。由于肌细胞拉伸释放血管紧张素II (AngII)，其结合AT1受体（AT1R）并在自分泌-旁分泌循环中刺激FAK和Src，我们测试了AT1R及其下游信号级联是否参与机械转导。将涂有β1-整合素单抗的顺磁珠涂于肌细胞，并用电磁铁向上拉，同时记录全细胞阴离子电流。Losartan （5 μM）是一种AT1R竞争拮抗剂，可以阻断Cl - SAC，但在没有整合素拉伸的情况下，不会显著改变背景Cl -电流。AT1R信号主要由肌层NADPH氧化酶产生的超氧化物产生的H2O2介导。Diphenyleneiodonium （DPI, 60 μM）是一种有效的NADPH氧化酶抑制剂，可以快速完全阻断拉伸引起的Cl - SAC和背景Cl -电流。一种结构无关的NADPH氧化酶抑制剂4-（2-氨基乙基）苯磺酰氟（AEBSF， 0.5和2mm）也能快速完全阻断Cl - SAC以及很大一部分背景Cl -电流。随着整合素的持续拉伸，Cl - SAC在AEBSF冲洗后恢复（2mm）。在没有拉伸的情况下，外源性AngII （5 nM）激活了一个向外整流的Cl−电流，该电流被DPI （60 μM）迅速完全阻断。此外，外源H2O2(10、100和500 μM)， NADPH氧化酶活性的最终产物，也会在没有拉伸的情况下激活Cl - SAC，而过氧化氢酶（1000 U/ml），一种H2O2清除剂，会减弱对拉伸的反应。然而，在DPI （60 μM）或AEBSF （0.5 mM）抑制NADPH氧化酶期间，H2O2的应用并没有完全激活Cl−SAC。这些结果表明，心肌细胞中β1-整合素的拉伸通过激活AT1R和NADPH氧化酶来诱导Cl - SAC，从而产生活性氧。此外，NADPH氧化酶可能与负责Cl - SAC的通道密切耦合，提供了第二种调控途径。
Direct stretch of β1 integrin activates an outwardly rectifying, tamoxifen-sensitive Cl− current (Cl− SAC) via focal adhesion kinase (FAK) and/or Src. The characteristics of Cl− SAC resemble those of the volume-sensitive Cl− current, ICl,swell. Because myocyte stretch releases angiotensin II (AngII), which binds AT1 receptors (AT1R) and stimulates FAK and Src in an autocrine-paracrine loop, we tested whether AT1R and their downstream signaling cascade participate in mechanotransduction. Paramagnetic beads coated with mAb for β1-integrin were applied to myocytes and pulled upward with an electromagnet while recording whole-cell anion current. Losartan (5 μM), an AT1R competitive antagonist, blocked Cl− SAC but did not significantly alter the background Cl− current in the absence of integrin stretch. AT1R signaling is mediated largely by H2O2 produced from superoxide generated by sarcolemmal NADPH oxidase. Diphenyleneiodonium (DPI, 60 μM), a potent NADPH oxidase inhibitor, rapidly and completely blocked both Cl− SAC elicited by stretch and the background Cl− current. A structurally unrelated NADPH oxidase inhibitor, 4-(2-aminoethyl) benzenesulfonyl fluoride (AEBSF, 0.5 and 2 mM), also rapidly and completely blocked Cl− SAC as well as a large fraction of the background Cl− current. With continuing integrin stretch, Cl− SAC recovered upon washout of AEBSF (2 mM). In the absence of stretch, exogenous AngII (5 nM) activated an outwardly rectifying Cl− current that was rapidly and completely blocked by DPI (60 μM). Moreover, exogenous H2O2 (10, 100, and 500 μM), the eventual product of NADPH oxidase activity, also activated Cl− SAC in the absence of stretch, whereas catalase (1,000 U/ml), an H2O2 scavenger, attenuated the response to stretch. Application of H2O2 during NADPH oxidase inhibition by either DPI (60 μM) or AEBSF (0.5 mM) did not fully reactivate Cl− SAC, however. These results suggest that stretch of β1-integrin in cardiac myocytes elicits Cl− SAC by activating AT1R and NADPH oxidase and, thereby, producing reactive oxygen species. In addition, NADPH oxidase may be intimately coupled to the channel responsible for Cl− SAC, providing a second regulatory pathway.
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DOI：
10.1006/bbrc.2001.5665
发表时间：
2001-10-05
影响因子：
3.1
作者：
Grandvaux, N;Elsen, S;Vignais, PV
通讯作者：
Vignais, PV
影响因子：
20.1
作者：
De Keulenaer, GW;Chappell, DC;Griendling, KK
通讯作者：
Griendling, KK
影响因子：
20.1
作者：
Brahmajothi, MV;Campbell, DL
通讯作者：
Campbell, DL
影响因子：
37.8
作者：
Bendall, JK;Cave, AC;Shah, AM
通讯作者：
Shah, AM
影响因子：
20.1
作者：
Clemo, HF;Stambler, BS;Baumgarten, CM
通讯作者：
Baumgarten, CM