LRRC8A channels support TNFα-induced superoxide production by Nox1 which is required for receptor endocytosis.
LRRC8A channels support TNFα-induced superoxide production by Nox1 which is required for receptor endocytosis.
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DOI：
10.1016/j.freeradbiomed.2016.11.003
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发表时间：
2016-12
影响因子：
7.4
通讯作者：
Lamb, Fred S.
中科院分区：
文献类型：
--
作者：
Choi, Hyehun;Ettinger, Nicholas;Rohrbough, Jeffrey;Dikalova, Anna;Nguyen, Hong N.;Lamb, Fred S.
关键词：
富含亮氨酸重复序列的8A（Leucine Rich Repeat Containing 8A，LRRC 8A）是容积调节阴离子通道（volume-regulated anion channels，VRAC）的必需组分。在血管平滑肌细胞中，肿瘤坏死因子-α（TNFα）通过1型TNFα受体（TNFR 1）激活VRAC，这需要NADPH氧化酶1（Nox 1）产生超氧化物（O2·−）。VRAC抑制剂通过未知机制抑制对TNFα的炎症反应。我们假设LRRC 8A直接支持Nox 1活性，提供VRAC电流和炎症信号之间的联系。4-（2-丁基-6，7-异丙基-2-环戊基茚满-1-酮-5-基）氧代丁酸（DCPIB）抑制VRAC可损害TNFα对NF-κB的激活。LRRC 8A siRNA可降低VRAC的幅度，抑制TNFα诱导的NF-κB活化、iNOS和VCAM表达以及VSMCs增殖。被siLRRC 8A和DCPIB破坏的信号步骤包括：Nox 1产生的细胞外O2·−，c-Jun N-末端激酶（JNK）磷酸化和TNFR 1的内吞作用。细胞外超氧化物歧化酶，而不是过氧化氢酶，选择性地抑制TNFR 1的内吞作用和JNK磷酸化。因此，O2·−是TNFR信号转导的关键细胞外氧化剂。减少JNK表达（siJNK）增加细胞外O2·−，表明JNK在质膜上对Nox 1提供重要的负反馈调节。LRRC 8A通过免疫染色共定位，并与Nox 1及其p22 phox亚基共免疫沉淀。LRRC 8A是Nox 1信号复合物的一个组成部分。它是细胞外O2·-产生所必需的，而细胞外O2·-产生又是TNFR 1内吞作用所必需的。这些数据首次为VRAC抑制的强效抗增殖和抗炎作用提供了分子机制。
Leucine Rich Repeat Containing 8A (LRRC8A) is a required component of volume-regulated anion channels (VRACs). In vascular smooth muscle cells, tumor necrosis factor-α (TNFα) activates VRAC via type 1 TNFα receptors (TNFR1), and this requires superoxide (O2•−) production by NADPH oxidase 1 (Nox1). VRAC inhibitors suppress the inflammatory response to TNFα by an unknown mechanism. We hypothesized that LRRC8A directly supports Nox1 activity, providing a link between VRAC current and inflammatory signaling. VRAC inhibition by 4-(2-butyl-6,7-dichlor-2-cyclopentylindan-1-on-5-yl) oxobutyric acid (DCPIB) impaired NF-κB activation by TNFα. LRRC8A siRNA reduced the magnitude of VRAC and inhibited TNFα-induced NF-κB activation, iNOS and VCAM expression, and proliferation of VSMCs. Signaling steps disrupted by both siLRRC8A and DCPIB included; extracellular O2•− production by Nox1, c-Jun N-terminal kinase (JNK) phosphorylation and endocytosis of TNFR1. Extracellular superoxide dismutase, but not catalase, selectively inhibited TNFR1 endocytosis and JNK phosphorylation. Thus, O2•− is the critical extracellular oxidant for TNFR signal transduction. Reducing JNK expression (siJNK) increased extracellular O2•− suggesting that JNK provides important negative feedback regulation to Nox1 at the plasma membrane. LRRC8A co-localized by immunostaining, and co-immunoprecipitated with, both Nox1 and its p22phox subunit. LRRC8A is a component of the Nox1 signaling complex. It is required for extracellular O2•− production, which is in turn essential for TNFR1 endocytosis. These data are the first to provide a molecular mechanism for the potent anti-proliferative and anti-inflammatory effects of VRAC inhibition.
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影响因子：
64.8
作者：
Duan, D;Winter, C;Horowitz, B
通讯作者：
Horowitz, B
影响因子：
8.2
作者：
Alibrahim, Ammar;Zhao, Li-yan;Sun, Hong-shuo
通讯作者：
Sun, Hong-shuo
影响因子：
5.3
作者：
Mumbengegwi, Davis R.;Li, Qiang;Engelhardt, John F.
通讯作者：
Engelhardt, John F.
影响因子：
4.9
作者：
Liang, Wenbin;Huang, Lihong;Backx, Peter H.
通讯作者：
Backx, Peter H.
DOI：
10.1073/pnas.88.7.2830
发表时间：
1991-04-01
影响因子：
11.1
作者：
LEWIS, M;TARTAGLIA, LA;GOEDDEL, DV
通讯作者：
GOEDDEL, DV