Calcium signalling in adult endothelial outgrowth cells

• Published in: Biochemical and biophysical research communications Vol. 417; no. 1; pp. 358 - 363
• Main Authors: Pierce, William G., Zanette, Christopher, Caplice, Noel M., Mackrill, John J.
• Format: Journal Article
• Language: English
• Published: United States Elsevier Inc 06.01.2012
• Subjects: Adult; Blood; Ca super(2+)-transporting ATPase; Calcium - metabolism; Calcium channels; Calcium channels (L-type); Calcium channels (voltage-gated); Calcium Channels, L-Type - biosynthesis; Calcium release channels; Calcium Signaling; Calcium signalling; Cells, Cultured; Collagen; Endoplasmic reticulum; Endothelial outgrowth cells; Endothelium, Vascular - metabolism; Fibrinogen; Fibrinogen - metabolism; Humans; Leukocytes (mononuclear); Plasma membrane calcium ATPase; Plasma membranes; Ryanodine receptor; Ryanodine Receptor Calcium Release Channel - biosynthesis; Ryanodine receptors; Voltage gated calcium channel; Endothelial outgrowth cells; Fibrinogen; Voltage gated calcium channel; Ryanodine receptor; Plasma membrane calcium ATPase
• ISSN: 0006-291X; 1090-2104
• DOI: 10.1016/j.bbrc.2011.11.115

► Endothelial outgrowth cells (EOCs) express ryanodine receptors and voltage gated calcium channels. ► Individual cells in an EOC population display heterogeneous calcium responses to fibrinogen or collagen. ► Increases in Ca2+ in response to fibrinogen involve ryanodine receptors and voltage gated calcium channels. ► Decreases in Ca2+ in response to fibrinogen are due to plasma membrane calcium ATPases. 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 Ca2+ signalling mechanisms. In the current study, it was found that human EOCs express two forms of ryanodine receptor (RyR1 and RyR2) Ca2+ release channel in their endoplasmic reticulum. Individual EOCs display heterogeneous Ca2+ responses to physiologically relevant regulators fibrinogen and collagen. Some EOCs showed distinctive, multiphasic Ca2+ responses to fibrinogen consisting of rapid decreases, transient increases then a gradual return to the resting levels. Transient elevations in Ca2+ required both L-type voltage gated calcium channels and RyRs. Decreases in Ca2+ stimulated by fibrinogen depended on plasma membrane Ca2+ ATPase pumps, but did not require thapsigargin-sensitive Ca2+ ATPases. These results indicate that EOCs possess sophisticated Ca2+ signalling mechanisms, capable of generating distinct Ca2+ waveforms in response to different physiologically relevant cues.