The purinergic P2Z receptor of human macrophage cells. Characterization and possible physiological role.
We have investigated responses of human monocyte/macrophage cells to extracellular ATP (ATPe). Freshly isolated peripheral blood monocytes showed responses linked to P2Y but not P2Z purinergic receptors; however, during in vitro macrophage differentiation, these cells also exhibited responses suggestive of the presence of the membrane-permeabilizing P2Z receptor. In fact, in human macrophages a brief (15-min) exposure to ATPe, but not other nucleotides, caused (1) a rapid and long-lasting plasma membrane depolarization; (2) a large increase in intracellular Ca2+ concentration followed by efflux of the Ca2+ indicator; (3) uptake of low molecular weight hydrophilic molecules such as Lucifer yellow and ethidium bromide; and (4) cell rounding, swelling, and eventual release of the cytoplasmic enzyme lactate dehydrogenase. rIFN-gamma enhanced both membrane-permeabilizing and cytotoxic ATPe effects. Membrane permeabilization and cytotoxicity were fully blocked by pretreatment of the cells with oxidized ATP, a compound recently shown to block P2Z receptors covalently in macrophages. Blocking of the P2Z receptor by oxidized ATP also inhibited multinucleated giant cell generation stimulated by concanavalin A or rIFN-gamma without decreasing monocyte migration or membrane adhesion molecule expression. These data suggest that human macrophages express rIFN-gamma-modulated purinergic P2Z receptors in vitro and hint at a role for these plasma membrane molecules in the generation of macrophage polykarions.
Falzoni
S
S
Institute of General Pathology, University of Ferrara, Italy.
Munerati
M
M
Ferrari
D
D
Spisani
S
S
Moretti
S
S
Di Virgilio
F
F
D000255:Adenosine Triphosphate / Q000378:metabolism / Q000494:pharmacology; D015703:Antigens, CD / Q000032:analysis; D001692:Biological Transport; D002118:Calcium / Q000378:metabolism; D016923:Cell Death; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D002634:Chemotaxis, Leukocyte / Q000187:drug effects; D004996:Ethidium / Q000378:metabolism; D005434:Flow Cytometry; D006801:Humans; D007371:Interferon-gamma / Q000494:pharmacology; D007546:Isoquinolines / Q000378:metabolism; D008264:Macrophages / Q000502:physiology*; D008564:Membrane Potentials; D009000:Monocytes / Q000502:physiology*; D018048:Receptors, Purinergic P2 / Q000145:classification / Q000502:physiology*; D015854:Up-Regulation; D014544:Uridine Triphosphate / Q000378:metabolism
D015703:Antigens, CD; D007546:Isoquinolines; D018048:Receptors, Purinergic P2; D007371:Interferon-gamma; D000255:Adenosine Triphosphate; C017475:lucifer yellow; D004996:Ethidium; D002118:Calcium; D014544:Uridine Triphosphate