Localized superoxide release by neutrophils can be provoked by a cytosolic calcium 'cloud'

Davies, E. V., Hallett, Maurice Bartlett ORCID: https://orcid.org/0000-0001-8197-834X and Campbell, A. K. 1991. Localized superoxide release by neutrophils can be provoked by a cytosolic calcium 'cloud'. Immunology 73 (2) , pp. 228-234.

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Abstract

We have used single-cell ratio imaging of Fura-2 loaded neutrophils to visualize release of cytosolic Ca2+ from an intracellular store in order to determine the location of this store and the relationship of release from it to oxidase activation. In the presence of extracellular Ca2+, N-formyl-L-methionyl-L-leucyl-L-phenylalanine (FMLP) produced an increase in free Ca2+ throughout the cytosol. In its absence, however, stimulation induced in 38% of neutrophils a highly localized increase in cytosolic free Ca2+, located between the nuclear lobes and the plasma membrane, at a region of cytosol which stained positively with 3,3'-dihexyloxacarbocyanine iodide [DiOC6(3)]. Calcium release from the store was transient, without oscillation and occurred after delays of up to 120 seconds. Addition of Ca2+ ionophore also released Ca2+ from this, and other stores, within the cell, up to three foci being detected in some cells. Localized oxidase activation occurred at the plasma membrane when the calcium concentration ([Ca2+]) of the 'cloud' exceeded 250 nM. Surprisingly, localized activation occurred at the plasma membrane at a site separate from but near to a region of high Ca2+. It was concluded that release of Ca2+ from a single receptor-releasable, Ca2+ store in neutrophils was insufficient to trigger oxidase activation throughout the cell, but could provide a localized activation of the oxidase

Item Type:	Article
Date Type:	Publication
Status:	Published
Schools:	Medicine
Subjects:	R Medicine > R Medicine (General)
Publisher:	Wiley Blackwell
ISSN:	0019-2805
Last Modified:	28 Oct 2022 09:04
URI:	https://orca.cardiff.ac.uk/id/eprint/73181

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