A role for Ca2+-conducting ion channels in mechanically-induced signal transduction of airway epithelial cells

S. Boitano, M. J. Sanderson, E. R. Dirksen

Research output: Contribution to journalArticle

72 Scopus citations

Abstract

Mechanical stimulation of a single cell in a cultured monolayer of airway epithelial cells initiates an intercellularly communicated increase in intracellular Ca2+ concentration ([Ca2+](i)) that propagates radially through adjacent cells via gap junctions, forming an intercellular Ca2+ wave. Mechanically-induced intercellular Ca2+ waves also occur in the absence of extracellular Ca2+. However, in Ca2+-free medium an increase in [Ca2+](i) of the stimulated cell does not occur. Thus, mechanically-induced [Ca2+](i) changes in the stimulated cell are influenced by the extracellular Ca2+ concentration. To investigate if a channel-mediated Ca2+ flux across the plasma membrane contributes to the elevation of [Ca2+](i) in the stimulated cell we used digital image microscopy to measure mechanically-induced [Ca2+](i) changes in the presence of Ca2+ channel blockers. In Ca2+-free medium containing Gd3+ (20 μM) mechanical stimulation resulted in an [Ca2+](i) increase in the stimulated cell. The delay time between mechanical stimulation and increase in [Ca2+](i) of the stimulated cell was dependent on extracellular [Gd3+], with a half-maximal effective concentration of approximately 40 μM. Mechanical stimulation in Ca2+-free medium containing La3+ (10 μM) or Ni2+ (100 μM) gave similar results. Mechanical stimulation in Ca2+-free medium containing the dihydropyridine Ca2+ channel blockers nifedipine (10 μM) and nimodipine (10 μM) also resulted in an increase of [Ca2+](i) of the stimulated cell. Mechanical stimulation of cells treated with thapsigargin to deplete intracellular Ca2+ stores, in the presence of 1.3 mM extracellular Ca2+, results in an increase in [Ca2+](i) of the stimulated cell without the propagation of an intercellular Ca2+ wave. Mechanical stimulation of thapsigargin-treated cells in an extracellular medium buffered to 50 μM free Ca2+ still results in an increase in [Ca2+](i) in the stimulated cell. However, the mechanically-induced Ca2+ increase in the presence of 50 μM extracellular [Ca2+] can be reversibly blocked by 100 μM Ni2+. From these results we conclude that a flux of Ca2+ across the plasma membrane and through Ca2+-conducting channels contributes to the mechanically-induced [Ca2+](i) changes in the stimulated cell.

Original languageEnglish (US)
Pages (from-to)3037-3044
Number of pages8
JournalJournal of Cell Science
Volume107
Issue number11
StatePublished - 1994

Keywords

  • Calcium
  • Dihydropyridine
  • Gd
  • Intercellular communication calcium wave
  • Ion channel
  • Mechanical stimulation

ASJC Scopus subject areas

  • Cell Biology

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