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Title

Spontaneous and chemoattractant-induced oscillations of cytosolic free calcium in single adherent human neutrophils

Authors
Jaconi, Marisa
Rivest, R. W.
Published in The Journal of biological chemistry. 1988, vol. 263, no. 22, p. 10557-10560
Abstract Studies with fluorescent Ca2+ indicators in large populations of neutrophils in suspension reveal a stable base line followed by a rapid agonist-induced elevation of cytosolic free calcium, [Ca2+]i, concomitant with other parameters of cellular activation. To study the role of adhesion in cell activation, we monitored [Ca2+]i in single neutrophils adhered to albumin-coated or fibronectin-coated glass coverslips before and after stimulation with the chemotactic peptide N-formyl-L-methionyl-L-leucyl-L-phenylalanine (fMLP). Human neutrophils loaded with 2 microM fura 2/AM were allowed to adhere to coverslips for 15-20 min at 37 degrees C. [Ca2+]i was monitored with a dual excitation microfluorimeter with a time resolution of 200 ms. Statistical analysis was performed using an algorithm allowing to detect significant [Ca2+]i peaks. 54% of the cells showed spontaneous [Ca2+]i oscillations. The amplitude of these [Ca2+]i peaks averaged 77 +/- 10 nM above basal levels (mean value of 110 +/- 20 nM), and their mean duration was 28 +/- 5 s; periods of [Ca2+]i bursts could last up to 15 min. In "silent" cells exhibiting a stable [Ca2+]i base line without spontaneous oscillations, low concentrations of fMLP (10(-10)-10(-9) M) could induce sustained [Ca2+]i oscillations. By contrast, higher agonist concentrations (10(-6) M) induced a single [Ca2+]i transient followed by a stable base line. 47% of the cells showing spontaneous [Ca2+]i oscillations did not respond to fMLP. Spontaneous [Ca2+]i oscillations depended on the continuous presence of extracellular Ca2+. Therefore: (i) spontaneous oscillations of [Ca2+]i occur in neutrophils adherent to various substrata; (ii) these oscillations do not preclude and can be dissociated from the response to fMLP; (iii) neutrophil functions might be controlled by [Ca2+]i oscillations rather than by sustained alterations of [Ca2+]i.
Keywords Calcium/ bloodCell AdhesionChemotaxis, LeukocyteCytosol/metabolismHumansKineticsN-Formylmethionine Leucyl-PhenylalanineNeutrophils/cytology/ physiology
Identifiers
PMID: 3392026
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Other version: http://www.jbc.org/content/263/22/10557.full.pdf
Structures
Research group Staphylocoques dorés résistants à la méthicilline et hygiène hospitalière (330)
Citation
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JACONI, Marisa et al. Spontaneous and chemoattractant-induced oscillations of cytosolic free calcium in single adherent human neutrophils. In: Journal of Biological Chemistry, 1988, vol. 263, n° 22, p. 10557-10560. doi: 10.1016/S0021-9258(18)38006-2 https://archive-ouverte.unige.ch/unige:11355

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Deposited on : 2010-08-27

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