STIM‐1 and ORAI‐1 channel mediate angiotensin‐II‐induced expression of Egr‐1 in vascular smooth muscle cells

• Published in: Journal of cellular physiology Vol. 232; no. 12; pp. 3496 - 3509
• Main Authors: Simo‐Cheyou, Estelle R., Tan, Ju Jing, Grygorczyk, Ryszard, Srivastava, Ashok K.
• Format: Journal Article
• Language: English
• Published: United States Wiley Subscription Services, Inc 01.12.2017
• Subjects: Activation; Angiotensin; Angiotensin II; Angiotensin II - pharmacology; Animals; Arteriosclerosis; Atherosclerosis; Ca2+/calmodulin-dependent protein kinase II; Calcium (intracellular); Calcium Channel Blockers - pharmacology; Calcium Signaling - drug effects; Calcium signalling; Calcium-binding protein; Calcium-Calmodulin-Dependent Protein Kinase Type 2 - antagonists & inhibitors; Calcium-Calmodulin-Dependent Protein Kinase Type 2 - metabolism; Calmodulin; Calmodulin - antagonists & inhibitors; Calmodulin - metabolism; Cell Line; CREB; Cyclic AMP response element-binding protein; Cyclic AMP Response Element-Binding Protein - metabolism; Depletion; Dose-Response Relationship, Drug; Early Growth Response Protein 1 - genetics; Early Growth Response Protein 1 - metabolism; EGR-1 protein; Egr‐1; Extracellular Signal-Regulated MAP Kinases - metabolism; Gene expression; Hyperplasia; Inositol 1,4,5-trisphosphate receptors; Inositol 1,4,5-Trisphosphate Receptors - antagonists & inhibitors; Inositol 1,4,5-Trisphosphate Receptors - metabolism; mRNA; Muscle, Smooth, Vascular - drug effects; Muscle, Smooth, Vascular - metabolism; Myocytes, Smooth Muscle - drug effects; Myocytes, Smooth Muscle - metabolism; ORAI1 Protein - genetics; ORAI1 Protein - metabolism; Orai‐1; Pathogenesis; Peptides; Phosphorylation; Protein Kinase Inhibitors - pharmacology; Rats; Ribonucleic acid; RNA; RNA Interference; RNA-mediated interference; siRNA; Smooth muscle; STIM1 protein; STIM‐1; Stromal Interaction Molecule 1 - genetics; Stromal Interaction Molecule 1 - metabolism; Time Factors; Transfection; Up-Regulation; Vascular diseases; Vasoactive agents; Egr-1; angiotensin-II; CREB; Orai-1; STIM-1
• ISSN: 0021-9541; 1097-4652
• DOI: 10.1002/jcp.25810

An upregulation of Egr‐1 expression has been reported in models of atherosclerosis and intimal hyperplasia and, various vasoactive peptides and growth promoting stimuli have been shown to induce the expression of Egr‐1 in vascular smooth muscle cells (VSMC). Angiotensin‐II (Ang‐II) is a key vasoactive peptide that has been implicated in the pathogenesis of vascular diseases. Ang‐II elevates intracellular Ca2+ through activation of the store‐operated calcium entry (SOCE) involving an inositol‐3‐phosphate receptor (IP3R)‐coupled depletion of endoplasmic reticular Ca2+ and a subsequent activation of the stromal interaction molecule 1 (STIM‐1)/Orai‐1 complex. However, the involvement of IP3R/STIM‐1/Orai‐1‐Ca2+‐dependent signaling in Egr‐1 expression in VSMC remains unexplored. Therefore, in the present studies, we have examined the role of Ca2+ signaling in Ang‐II‐induced Egr‐1 expression in VSMC and investigated the contribution of STIM‐1 or Orai‐1 in mediating this response. 2‐aminoethoxydiphenyl borate (2‐APB), a dual non‐competitive antagonist of IP3R and inhibitor of SOCE, decreased Ang‐II‐induced Ca2+ release and attenuated Ang‐II‐induced enhanced expression of Egr‐1 protein and mRNA levels. Egr‐1 upregulation was also suppressed following blockade of calmodulin and CaMKII. Furthermore, RNA interference‐mediated depletion of STIM‐1 or Orai‐1 attenuated Ang‐II‐induced Egr‐1 expression as well as Ang‐II‐induced phosphorylation of ERK1/2 and CREB. In addition, siRNA‐induced silencing of CREB resulted in a reduction in the expression of Egr‐1 stimulated by Ang‐II. In summary, our data demonstrate that Ang‐II‐induced Egr‐1 expression is mediated by STIM‐1/Orai‐1/Ca2+‐dependent signaling pathways in A‐10 VSMC. Angiotensin‐II‐induced intracellular calcium release depletes the endoplasmic reticulum store, resulting in the activation of the stromal interaction molecule 1 (STIM1) known to cooperate with Orai‐1 transmembrane channel in mediating store‐operated calcium entry (SOCE) in the cells. In this study, we demonstrate that intact SOCE and unaltered expression of STIM‐1 and Orai‐1, in association with an involvement of calcium signaling molecules such as calmodulin and CaMKII, are required for Ang‐II‐dependent induction of the early growth response protein‐1 in VSMC. We also provide evidence of the critical role played by ERK1/2 and CREB activation in mediating this response.