title: Calcium signalling in adult endothelial outgrowth cells.
abstract: Endothelial outgrowth cells (EOCs) derived from blood mononuclear cells can differentiate to an endothelial-like phenotype. There are deficits in understanding of the biology of these cells, particularly detailed characterisation of their Ca(2+) signalling mechanisms. In the current study, it was found that human EOCs express two forms of ryanodine receptor (RyR1 and RyR2) Ca(2+) release channel in their endoplasmic reticulum. Individual EOCs display heterogeneous Ca(2+) responses to physiologically relevant regulators fibrinogen and collagen. Some EOCs showed distinctive, multiphasic Ca(2+) responses to fibrinogen consisting of rapid decreases, transient increases then a gradual return to the resting levels. Transient elevations in Ca(2+) required both L-type voltage gated calcium channels and RyRs. Decreases in Ca(2+) stimulated by fibrinogen depended on plasma membrane Ca(2+) ATPase pumps, but did not require thapsigargin-sensitive Ca(2+) ATPases. These results indicate that EOCs possess sophisticated Ca(2+) signalling mechanisms, capable of generating distinct Ca(2+) waveforms in response to different physiologically relevant cues.
authors.affiliation: Department of Physiology, University College Cork, BioSciences Institute, College Road, Cork, Ireland.
authors.forename: William G
authors.initials: WG
authors.lastname: Pierce
authors.forename: Christopher
authors.initials: C
authors.lastname: Zanette
authors.forename: Noel M
authors.initials: NM
authors.lastname: Caplice
authors.forename: John J
authors.initials: JJ
authors.lastname: Mackrill
mesh_terms: D000328:Adult; D002118:Calcium / Q000378:metabolism*; D020746:Calcium Channels, L-Type / Q000096:biosynthesis; D020013:Calcium Signaling; D002478:Cells, Cultured; D004730:Endothelium, Vascular / Q000378:metabolism*; D005340:Fibrinogen / Q000378:metabolism; D006801:Humans; D019837:Ryanodine Receptor Calcium Release Channel / Q000096:biosynthesis
chemical_list: D020746:Calcium Channels, L-Type; D019837:Ryanodine Receptor Calcium Release Channel; D005340:Fibrinogen; D002118:Calcium