Release of 'caged' cytosolic Ca2+ triggers rapid spreading of human neutrophils adherent via integrin engagement.
The role of the transient rise in cytosolic free Ca2+ which occurs during neutrophil adhesion and cell spreading is unclear. In order to establish whether such a Ca2+ signal triggers neutrophil shape change, neutrophils co-loaded with fluo3 and Nitr5 ('caged' Ca2+) were used with rapid-time confocal laser scanning microscopy. Here we show that the photolytic generation of a Ca2+ rise in neutrophils which were adherent to an integrin-engaging surface, triggered a rapid change in cell morphology, with increases in cell diameter of approximately 175% occurring within 90 seconds of the Ca2+ signal. In non-adhered neutrophils or neutrophils on plain glass, no acceleration of the rate of spreading occurring in response to the release of 'caged Ca2+' could be demonstrated. It was concluded that although a rise in cytosolic free Ca2+ was not the sole trigger for neutrophil shape change, with other signals generated by integrin engagement, a rise in cytosolic free Ca2+ accelerated the rate of neutrophil spreading.
Pettit
E J
EJ
Molecular Signalling Group, Department of Surgery, University of Wales College of Medicine, Heath Park, Cardiff CF4 4XN, UK.
Hallett
M B
MB
D018821:CD18 Antigens / Q000032:analysis; D002118:Calcium / Q000378:metabolism*; D002448:Cell Adhesion / Q000502:physiology*; D048429:Cell Size; D002614:Chelating Agents; D003600:Cytosol / Q000378:metabolism*; D004533:Egtazic Acid / Q000031:analogs & derivatives; D006801:Humans; D016023:Integrins / Q000378:metabolism*; D016177:Macrophage-1 Antigen / Q000032:analysis; D018613:Microscopy, Confocal; D009504:Neutrophils / Q000166:cytology*; D010782:Photolysis
D018821:CD18 Antigens; D002614:Chelating Agents; D016023:Integrins; D016177:Macrophage-1 Antigen; C052455:nitr 5; D004533:Egtazic Acid; D002118:Calcium