Intracellular pattern of cytosolic Ca2+ changes during adhesion and multiple phagocytosis in human neutrophils. Dynamics of intracellular Ca2+ stores.
The subcellular pattern of cytosolic free Ca2+ ([Ca2+]i) changes in human polymorphonuclear neutrophils (PMNs) was studied using imaging of fura-2 fluorescence (time resolution 12.5 ratios/s) to determine whether PMNs could obtain directional information from the [Ca2+]i signal. [Ca2+]i changes were observed during initial adherence, the subsequent chemotactic movement, and the phagocytosis of opsonized yeast particles. Initial adherence was followed by a rapid increase in [Ca2+]i (from 90 +/- 10 to 290 +/- 40 nmol/L in 6.5 +/- 2.5 seconds; +/- SEM, n = 10), apparently homogeneously distributed over the entire cytoplasm, which preceded the spreading of the PMNs. [Ca2+]i increases after the contact of the PMNs with yeast particles were of lower mean amplitude; [Ca2+]i increased simultaneously throughout the cytosol. In the absence of extracellular Ca2+, multiple phagocytotic events could proceed normally without a mandatory [Ca2+]i transient. In PMNs polarized on phagocytosis, gradients in [Ca2+]i could be observed. [Ca2+]i was more elevated in the periphagosomal area than in the remaining parts. Taken together, these data show that [Ca2+]i waves do not provide the neutrophil with directional information during chemotaxis and phagocytosis. Sustained small inhomogeneity of [Ca2+]i levels are consistent with a proposed redistribution of releasable Ca2+ stores on phagocytosis.
Theler
J M
JM
Division de Biochimie Clinique, Centre Médical Universitaire, Geneva, Switzerland.
Lew
D P
DP
Jaconi
M E
ME
Krause
K H
KH
Wollheim
C B
CB
Schlegel
W
W
D000328:Adult; D002118:Calcium / Q000378:metabolism*; D002448:Cell Adhesion; D002451:Cell Compartmentation; D002634:Chemotaxis, Leukocyte; D003165:Complement System Proteins; D003600:Cytosol / Q000737:chemistry; D006801:Humans; D007091:Image Processing, Computer-Assisted; D007424:Intracellular Fluid / Q000737:chemistry; D009504:Neutrophils / Q000737:chemistry / Q000502:physiology* / Q000648:ultrastructure; D010587:Phagocytosis; D012441:Saccharomyces cerevisiae; D014743:Videotape Recording
D003165:Complement System Proteins; D002118:Calcium