Oxidant-mediated cAMP response element binding protein activation - Calcium regulation and role in apoptosis of lung epithelial cells
Oxidant-mediated cAMP response element binding protein activation - Calcium regulation and role in apoptosis of lung epithelial cells
复制标题
DOI：
10.1165/rcmb.2005-0153oc
复制
发表时间：
2006-01-01
影响因子：
6.4
通讯作者：
Lounsbury, KM
中科院分区：
文献类型：
--
作者：
Barlow, C;Shukla, A;Lounsbury, KM
氧化应激介导的细胞外信号调节激酶 (ERK1/2) 调节与肺上皮的病理结果相关，但 Ca2+ 和 Ca2+/cAMP 反应元件结合蛋白 (CREB) 在 ERK1/2 信号传导中的作用尚未明确。在本研究中，我们测试了以下假设：氧化剂诱导 Ca2+ 介导的 ERK 和 CREB 磷酸化，并且 CREB 是氧化剂诱导的增殖和凋亡所必需的。 H2O2 引发细胞外 Ca2+ 的流入，这是 C10 肺上皮细胞中 ERK 和 CREB 磷酸化所需的。 H2O2 介导的 CREB 磷酸化对 MEK 抑制敏感，表明 Ca2+、ERK 和 CREB 信号通路之间的串扰有助于氧化剂诱导的反应。使用显性失活 CREB 构建体降低 CREB 活性，抑制了 c-fos 稳态 mRNA 水平，但在 H2O2 暴露后却意外地增强了 bcl-2 稳态 mRNA 水平。虽然抑制 CREB 活性对 H2O2 刺激细胞周期没有可检测到的影响，但 CREB 活性的丧失却显着减少了细胞凋亡的数量。这些数据支持 H2O2 引发的 Ca2+-ERK1/2 和 CREB 之间的新型通讯，并进一步提供证据表明 CREB 是肺上皮细胞氧化剂介导的细胞凋亡的重要调节剂。
Oxidant stress-mediated regulation of extracellular signal-regulated kinases (ERK1/2) is linked to pathologic outcomes in lung epithelium, yet a role for Ca2+ and Ca2+/cAMP-response element binding protein (CREB) in ERK1/2 signaling has not been defined. In this study, we tested the hypotheses that oxidants induce Ca2+-mediated phosphorylation of ERK and CREB, and that CREB is required for oxidant-induced proliferation and apoptosis. H2O2 initiated an influx of extracellular Ca2+ that was required for phosphorylation of both ERK and CREB in C10 lung epithelial cells. H2O2-mediated CREB phosphorylation was sensitive to MEK inhibition, suggesting that crosstalk between Ca2+, ERK, and CREB signaling pathways contributes to the oxidant-induced response. Reduction of CREB activity, using a dominant-negative CREB construct, inhibited c-fos steady-state mRNA levels, but unexpectedly enhanced bcl-2 steady-state mRNA levels after H2O2 exposure. Whereas inhibition of CREB activity had no detectable effect on H2O2 stimulation of cell cycle, loss of CREB activity significantly reduced the number of cells undergoing apoptosis. These data support a novel communication between Ca2+-ERK1/2 and CREB elicited by H2O2, and further provide evidence that CREB is an important regulator of apoptosis in oxidant mediated responses of lung epithelial cells.