Characterization of the cytotoxic effect of extracellular ATP in J774 mouse macrophages.
Extracellular ATP (ATPo) is known to be cytotoxic to many cell types through a mechanism which is largely unknown. Very recently this nucleotide has been shown to cause cell death by apoptosis, probably by interacting with specific cell-surface receptors. In the present study we have investigated the mechanism of ATPo-dependent cytotoxicity in the macrophage-like mouse cell line J774. It has been previously reported that in this cell type ATPo activates trans-membrane Ca2+ and Na+ fluxes and a drastic increase in the plasma-membrane permeability to hydrophilic solutes smaller than 900 Da. These changes are followed by cell swelling and lysis. We show in the present study that, although this nucleotide triggers a rise in the cytoplasmic Ca2+ concentration, neither cell swelling nor lysis is Ca(2+)-dependent. Furthermore, cell lysis is not dependent on Na+ influx, as it is not prevented by iso-osmotic replacement of extracellular Na+ with choline or N-methylglucamine. On the contrary, ATPo-dependent cytotoxicity, but not the ATPo-dependent increase in plasma-membrane permeability, is completely abrogated in sucrose medium. Under our experimental conditions ATPo does not cause DNA fragmentation in J774 cells. We conclude from these findings that ATPo does not cause apoptosis of J774 macrophages and promotes a Ca(2+)- and Na(+)-independent colloido-osmotic lysis.
Murgia
M
M
C.N.R. Center for the Study of the Physiology of Mitochondria, University of Padova, Italy.
Pizzo
P
P
Steinberg
T H
TH
Di Virgilio
F
F
D000255:Adenosine Triphosphate / Q000633:toxicity*; D000818:Animals; D017209:Apoptosis / Q000187:drug effects / Q000502:physiology; D002118:Calcium / Q000378:metabolism; D002412:Cations / Q000378:metabolism / Q000494:pharmacology; D016923:Cell Death / Q000187:drug effects / Q000502:physiology; D002463:Cell Membrane Permeability / Q000187:drug effects; D048429:Cell Size / Q000187:drug effects; D002478:Cells, Cultured; D004247:DNA / Q000187:drug effects; D005110:Extracellular Space / Q000378:metabolism; D007700:Kinetics; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D008264:Macrophages / Q000166:cytology / Q000187:drug effects* / Q000201:enzymology; D051379:Mice; D009995:Osmosis; D011983:Receptors, Purinergic / Q000502:physiology; D012964:Sodium / Q000378:metabolism / Q000494:pharmacology
D002412:Cations; D011983:Receptors, Purinergic; D000255:Adenosine Triphosphate; D004247:DNA; D012964:Sodium; D007770:L-Lactate Dehydrogenase; D002118:Calcium