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

J Biol Chem. 2011 May 6;286(18):16186-96. doi: 10.1074/jbc.M110.198952. Epub 2011 Mar 14.

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+).

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Anti-Inflammatory Agents, Non-Steroidal / pharmacology*
  • Calcium / metabolism*
  • Calcium Channels / metabolism*
  • Cell Line, Tumor
  • Cell Proliferation / drug effects*
  • Ion Channel Gating / drug effects*
  • Membrane Potential, Mitochondrial / drug effects
  • Mitochondria, Muscle / metabolism*
  • Mitochondria, Muscle / pathology
  • Myocytes, Smooth Muscle / metabolism*
  • Myocytes, Smooth Muscle / pathology
  • Rats
  • Vascular Diseases / metabolism
  • Vascular Diseases / pathology

Substances

  • Anti-Inflammatory Agents, Non-Steroidal
  • Calcium Channels
  • Calcium