title: Nonsteroidal anti-inflammatory drugs inhibit vascular smooth muscle cell proliferation by enabling the Ca2+-dependent inactivation of calcium release-activated calcium/orai channels normally prevented by mitochondria.
abstract: Abnormal vascular smooth muscle cell (VSMC) proliferation contributes to occlusive and proliferative disorders of the vessel wall. Salicylate and other nonsteroidal anti-inflammatory drugs (NSAIDs) inhibit VSMC proliferation by an unknown mechanism unrelated to anti-inflammatory activity. In search for this mechanism, we have studied the effects of salicylate and other NSAIDs on subcellular Ca(2+) homeostasis and Ca(2+)-dependent cell proliferation in rat aortic A10 cells, a model of neointimal VSMCs. We found that A10 cells displayed both store-operated Ca(2+) entry (SOCE) and voltage-operated Ca(2+) entry (VOCE), the former being more important quantitatively than the latter. Inhibition of SOCE by specific Ca(2+) released-activated Ca(2+) (CRAC/Orai) channels antagonists prevented A10 cell proliferation. Salicylate and other NSAIDs, including ibuprofen, indomethacin, and sulindac, inhibited SOCE and thereby Ca(2+)-dependent, A10 cell proliferation. SOCE, but not VOCE, induced mitochondrial Ca(2+) uptake in A10 cells, and mitochondrial depolarization prevented SOCE, thus suggesting that mitochondrial Ca(2+) uptake controls SOCE (but not VOCE) in A10 cells. NSAIDs depolarized mitochondria and prevented mitochondrial Ca(2+) uptake, suggesting that they favor the Ca(2+)-dependent inactivation of CRAC/Orai channels. NSAIDs also inhibited SOCE in rat basophilic leukemia cells where mitochondrial control of CRAC/Orai is well established. NSAIDs accelerate slow inactivation of CRAC currents in rat basophilic leukemia cells under weak Ca(2+) buffering conditions but not in strong Ca(2+) buffer, thus excluding that NSAIDs inhibit SOCE directly. Taken together, our results indicate that NSAIDs inhibit VSMC proliferation by facilitating the Ca(2+)-dependent inactivation of CRAC/Orai channels which normally is prevented by mitochondria clearing of entering Ca(2+).
authors.affiliation: Institute of Molecular Biology and Genetics, University of Valladolid and Spanish Research Council, Valladolid, Spain.
authors.forename: Eva
authors.initials: E
authors.lastname: Muñoz
authors.forename: Ruth A
authors.initials: RA
authors.lastname: Valero
authors.forename: Ariel
authors.initials: A
authors.lastname: Quintana
authors.forename: Markus
authors.initials: M
authors.lastname: Hoth
authors.forename: Lucía
authors.initials: L
authors.lastname: Núñez
authors.forename: Carlos
authors.initials: C
authors.lastname: Villalobos
mesh_terms: D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000378:metabolism*; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects*; D015640:Ion Channel Gating / Q000187:drug effects*; D053078:Membrane Potential, Mitochondrial / Q000187:drug effects; D008931:Mitochondria, Muscle / Q000378:metabolism* / Q000473:pathology; D032389:Myocytes, Smooth Muscle / Q000378:metabolism* / Q000473:pathology; D051381:Rats; D014652:Vascular Diseases / Q000378:metabolism / Q000473:pathology
chemical_list: D000894:Anti-Inflammatory Agents, Non-Steroidal; D015220:Calcium Channels; D002118:Calcium