β2-integrin-mediated adhesion and intracellular Ca 2+ release in human eosinophils

Jennifer L. Bankers-Fulbright, Kathleen R. Bartemes, Gail M. Kephart, Hirohito Kita, Scott M. O'Grady

Research output: Contribution to journalArticle

5 Citations (Scopus)

Abstract

Human eosinophils spontaneously adhere to various substrates in the absence of exogenously added activators. In the present study a method was developed for characterizing eosinophil adhesion by measuring changes in impedance. Impedance measurements were performed in HCO3-buffered HybriCare medium maintained in a humidified 5% CO2 incubator at 37°C. Impedance increased by more than 1 kΩ within minutes after eosinophils made contact with the substrate, reaching a peak within 20 min. Blocking mobilization of intracellular [Ca2+] that precedes adhesion with BAPTA-AM (10 μM) completely inhibited the rise in impedance as well as the changes in cell shape typically observed in adherent cells. However, lowering the extracellular [Ca2+] with 2.5 mM EGTA did not inhibit the increase in impedance. Pretreatment with anti-CD18 antibody to block substrate interactions with β2-integrins, or jasplakinolide (2 μM) to block actin reorganization, abolished the increase in impedance and adherent morphology of the cells. Exposure of eosinophils to the phosphatidylinositol 3 kinase inhibitor LY294002 (5 μM) or treatment with protein kinase C zeta pseudosubstrate to competitively inhibit activity of the enzyme significantly reduced the increase in impedance and inhibited the cell spreading associated with adhesion. These results demonstrate a novel method for measuring eosinophil adhesion and showed that, following formation of a tethered attachment, a rapid increase in intracellular [Ca2+] precedes the cytoskeletal rearrangements required for cell shape changes and plasma membrane-substrate interactions associated with adhesion.

Original languageEnglish (US)
Pages (from-to)99-109
Number of pages11
JournalJournal of Membrane Biology
Volume228
Issue number2
DOIs
StatePublished - Mar 2009

Fingerprint

Electric Impedance
Eosinophils
Integrins
jasplakinolide
Cell Shape
Phosphatidylinositol 3-Kinase
Incubators
2-(4-morpholinyl)-8-phenyl-4H-1-benzopyran-4-one
Egtazic Acid
Actins
Anti-Idiotypic Antibodies
Cell Membrane
Enzymes

Keywords

  • β-Integrin
  • Actin
  • Degranulation
  • Major basic protein
  • PI-3 kinase

ASJC Scopus subject areas

  • Biophysics
  • Physiology
  • Cell Biology
  • Medicine(all)

Cite this

β2-integrin-mediated adhesion and intracellular Ca 2+ release in human eosinophils. / Bankers-Fulbright, Jennifer L.; Bartemes, Kathleen R.; Kephart, Gail M.; Kita, Hirohito; O'Grady, Scott M.

In: Journal of Membrane Biology, Vol. 228, No. 2, 03.2009, p. 99-109.

Research output: Contribution to journalArticle

Bankers-Fulbright, Jennifer L. ; Bartemes, Kathleen R. ; Kephart, Gail M. ; Kita, Hirohito ; O'Grady, Scott M. / β2-integrin-mediated adhesion and intracellular Ca 2+ release in human eosinophils. In: Journal of Membrane Biology. 2009 ; Vol. 228, No. 2. pp. 99-109.
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