Exposure of endothelial cells to cyclic strain induces elevations of cytosolic Ca 2+ concentration through mobilization of intracellular and extracellular pools

Oscar R. Rosales, Carlos M Isales, Paula Q. Barrett, Colleen Brophy, Bauer E. Sumpio

Research output: Contribution to journalArticle

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Abstract

We have previously reported that exposure of endothelial cells to cyclic strain elicited a rapid but transient generation of inositol 1,4,5-trisphosphate (IP 3 ), which reached a peak 10 s after the initiation of cyclic deformation. To address the effect of cyclic strain on intracellular Ca 2+ concentration ([Ca 2+ ] i ) and its temporal relationship to IP 3 generation, confluent bovine aortic endothelial cells were grown on flexible membranes, loaded with aequorin and the membranes placed in a custom-designed flow-through chamber. The chamber was housed inside a photomultiplier tube, and vacuum was utilized to deform the membranes. Our results indicate that the initiation of 10% average strain induced a rapid increase in [Ca 2+ ] i which contained two distinct components: a large initial peak 12 s after the initiation of stretch which closely followed the IP 3 peak, and a subsequent lower but sustained phase. Pretreatment with 5 μM GdCl 3 for 10 min or nominally Ca 2+ -free medium (CFM) for 3 min reduced the magnitude of the initial rise and abolished the sustained phase. Repetitive 10 % average strain at a frequency of 60 cycles/min also elicited a single IP 3 peak at 10 s. However, there was also a large initial [Ca 2+ J i peak followed by multiple smaller transient [Ca 2+ ] i elevations. Preincubation with 5μM GdCl 3 or CFM diminished the initial [Ca 2+ ] i transient and markedly inhibited the late-phase component. Preincubation with 25 μM 2,5-di-(t-butyl)-1,4-benzohydroquinone (BHQ) attenuated the initial [Ca 2+ ] i transient. Cyclic-strain-mediated IP 3 formation in confluent endothelial cells at 10 s, however, was not modified by pretreatment with 25 μM BHQ, 500 μM NiCl 2 , 10 nM charybdotoxin, 5 μM GdCl 3 or CFM. We conclude that in endothelial cells exposed to cyclic strain, Ca 2+ enters the cytosol from intracellular and extracellular pools but IP 3 formation is not dependent on Ca 2+ entry via the plasma membrane.

Original languageEnglish (US)
Pages (from-to)385-392
Number of pages8
JournalBiochemical Journal
Volume326
Issue number2
DOIs
StatePublished - Sep 1 1997

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Endothelial cells
Endothelial Cells
Membranes
Aequorin
Charybdotoxin
Inositol 1,4,5-Trisphosphate
Vacuum
Cytosol
Photomultipliers
Cell Membrane
Cell membranes

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Cite this

Exposure of endothelial cells to cyclic strain induces elevations of cytosolic Ca 2+ concentration through mobilization of intracellular and extracellular pools . / Rosales, Oscar R.; Isales, Carlos M; Barrett, Paula Q.; Brophy, Colleen; Sumpio, Bauer E.

In: Biochemical Journal, Vol. 326, No. 2, 01.09.1997, p. 385-392.

Research output: Contribution to journalArticle

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