Store-independent Orai1/3 channels activated by intracrine leukotrienec4: Role in neointimal hyperplasia

José C. González-Cobos, Xuexin Zhang, Wei Zhang, Brian Ruhle, Rajender K. Motiani, Rainer Schindl, Martin Muik, Amy M. Spinelli, Jonathan M. Bisaillon, Arti V. Shinde, Marc Fahrner, Harold A. Singer, Khalid Matrougui, Margarida Barroso, Christoph Romanin, Mohamed Trebak

Research output: Contribution to journalArticlepeer-review

109 Scopus citations


RATIONALE: Through largely unknown mechanisms, Ca2+ signaling plays important roles in vascular smooth muscle cell (VSMC) remodeling. Orai1-encoded store-operated Ca2+ entry has recently emerged as an important player in VSMC remodeling. However, the role of the exclusively mammalian Orai3 protein in native VSMC Ca2+ entry pathways, its upregulation during VSMC remodeling, and its contribution to neointima formation remain unknown. OBJECTIVE: The goal of this study was to determine the agonist-evoked Ca2+ entry pathway contributed by Orai3; Orai3 potential upregulation and role during neointima formation after balloon injury of rat carotid arteries. METHODS AND RESULTS: Ca2+ imaging and patch-clamp recordings showed that although the platelet-derived growth factor activates the canonical Ca2+ release-activated Ca2+ channels via store depletion in VSMC, the pathophysiological agonist thrombin activates a distinct Ca2+-selective channel contributed by Orai1, Orai3, and stromal interacting molecule1 in the same cells. Unexpectedly, Ca2+ store depletion is not required for activation of Orai1/3 channel by thrombin. Rather, the signal for Orai1/3 channel activation is cytosolic leukotrieneC4 produced downstream thrombin receptor stimulation through the catalytic activity of leukotrieneC4 synthase. Importantly, Orai3 is upregulated in an animal model of VSMC neointimal remodeling, and in vivo Orai3 knockdown inhibits neointima formation. CONCLUSIONS: These results demonstrate that distinct native Ca 2+-selective Orai channels are activated by different agonists/pathways and uncover a mechanism whereby leukotrieneC4 acts through hitherto unknown intracrine mode to elicit store-independent Ca 2+ signaling that promotes vascular occlusive disease. Orai3 and Orai3-containing channels provide novel targets for control of VSMC remodeling during vascular injury or disease.

Original languageEnglish (US)
Pages (from-to)1013-1025
Number of pages13
JournalCirculation research
Issue number7
StatePublished - Mar 29 2013

All Science Journal Classification (ASJC) codes

  • Physiology
  • Cardiology and Cardiovascular Medicine


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