DebRoy Auditi, Vogel Stephen M, Soni Dheeraj, Sundivakkam Premanand C, Malik Asrar B, Tiruppathi Chinnaswamy
From the Department of Pharmacology and Center for Lung and Vascular Biology, College of Medicine, University of Illinois, Chicago, Illinois 60612.
From the Department of Pharmacology and Center for Lung and Vascular Biology, College of Medicine, University of Illinois, Chicago, Illinois 60612
J Biol Chem. 2014 Aug 29;289(35):24188-201. doi: 10.1074/jbc.M114.570051. Epub 2014 Jul 11.
Stromal interacting molecule 1 (STIM1) regulates store-operated Ca(2+) entry (SOCE). Here we show that STIM1 expression in endothelial cells (ECs) is increased during sepsis and, therefore, contributes to hyperpermeability. LPS induced STIM1 mRNA and protein expression in human and mouse lung ECs. The induced STIM1 expression was associated with augmented SOCE as well as a permeability increase in both in vitro and in vivo models. Because activation of both the NF-κB and p38 MAPK signaling pathways downstream of TLR4 amplifies vascular inflammation, we studied the influence of these two pathways on LPS-induced STIM1 expression. Inhibition of either NF-κB or p38 MAPK activation by pharmacological agents prevented LPS-induced STIM1 expression. Silencing of the NF-κB proteins (p65/RelA or p50/NF-κB1) or the p38 MAPK isoform p38α prevented LPS-induced STIM1 expression and increased SOCE in ECs. In support of these findings, we found NF-κB and AP1 binding sites in the 5'-regulatory region of human and mouse STIM1 genes. Further, we demonstrated that LPS induced time-dependent binding of the transcription factors NF-κB (p65/RelA) and AP1 (c-Fos/c-Jun) to the STIM1 promoter. Interestingly, silencing of c-Fos, but not c-Jun, markedly reduced LPS-induced STIM1 expression in ECs. We also observed that silencing of p38α prevented c-Fos expression in response to LPS in ECs, suggesting that p38α signaling mediates the expression of c-Fos. These results support the proposal that cooperative signaling of both NF-κB and AP1 (via p38α) amplifies STIM1 expression in ECs and, thereby, contributes to the lung vascular hyperpermeability response during sepsis.
基质相互作用分子1（STIM1）调节钙库操纵性钙内流（SOCE）。我们在此表明，脓毒症期间内皮细胞（ECs）中STIM1的表达增加，因此导致血管通透性增加。脂多糖（LPS）诱导人和小鼠肺ECs中STIM1 mRNA和蛋白表达。诱导的STIM1表达与体外和体内模型中SOCE增强以及通透性增加相关。由于Toll样受体4（TLR4）下游的核因子κB（NF-κB）和p38丝裂原活化蛋白激酶（MAPK）信号通路的激活都会放大血管炎症，我们研究了这两条通路对LPS诱导的STIM1表达的影响。用药物抑制NF-κB或p38 MAPK激活可阻止LPS诱导的STIM1表达。沉默NF-κB蛋白（p65/RelA或p50/NF-κB1）或p38 MAPK亚型p38α可阻止LPS诱导的STIM1表达，并增加ECs中的SOCE。为支持这些发现，我们在人和小鼠STIM1基因的5'调控区域发现了NF-κB和激活蛋白1（AP1）结合位点。此外，我们证明LPS诱导转录因子NF-κB（p65/RelA）和AP1（c-Fos/c-Jun）与STIM1启动子的时间依赖性结合。有趣的是，沉默c-Fos而非c-Jun可显著降低ECs中LPS诱导的STIM1表达。我们还观察到沉默p38α可阻止ECs中LPS诱导的c-Fos表达，提示p38α信号传导介导c-Fos的表达。这些结果支持以下观点：NF-κB和AP1（通过p38α）的协同信号传导放大了ECs中STIM1的表达，从而导致脓毒症期间肺血管通透性增加反应。
