Extracellular atp causes apoptosis and necrosis of cultured
mesangial cells via p2z/p2x7 receptors.
Schulze-Lohoff, Eckhard, Christian Hugo, Sylvia Rost, Susanne Arnold,
Angela Gruber, Bernhard Br[umlaut]une, and Ralf Bernd Sterzel.
Nephrologisches Labor, Medizinische Klinik IV, Universit[umlaut]at
Erlangen-N[umlaut]urnberg, D-91054 Erlangen, Germany
APStracts 5:0160F, 1998.
Mesangial cells undergo cell death both by apoptosis and necrosis
during glomerular disease. Since nucleotides are released from
injured and destroyed cells in the glomerulus, we examined whether
extracellular ATP and its receptors may regulate cell death of
cultured mesangial cells. Addition of extracellular ATP (300 _M - 5
mM) to cultured rat mesangial cells for 90 min caused a 5.8-fold
increase in DNA fragment_ation (terminal deoxynucleotidyl transferase
assay) and a 4.2-fold increase in protein levels of the tumor
suppressor p53 which is thought to regulate apoptosis. Apoptotic DNA
fragmentation was confirmed by the diphenylamine assay and by
staining with the DNA-specific fluorochrome Hoechst 33258. The
necrotic markers, release of lactate dehydrogenase and uptake of
trypan blue, were not positive before three hours of ATP addition.
The effects of ATP on DNA fragmentation and p53 expression were
reproduced by the purinergic P2Z/P2X7 receptor agonist, 3_-O-(4_
-benzoyl)-benzoyl-ATP, and inhibited by the P2Z/P2X7 receptor blocker,
oxidized ATP. Transcripts encoding the P2Z/P2X7 receptor were
expressed by cultured mesangial cells as determined by Northern blot
analysis. P2Z/P2X7 receptor-associated pore formation in the plasma
membrane was demonstrated by the lucifer yellow assay. We conclude
that activation of P2Z/P2X7 receptors by extracellular ATP causes
apoptosis and necrosis of cultured mesangial cells. Activation of
purinergic P2Z/P2X7 receptors may play a role in causing death of
mesangial cells during glomerular disease.
Received 7 May 1998; accepted in final form 3 September 1998.
APS Manuscript Number F109-8.
Article publication pending Am. J. Physiol. (Renal Physiology).
ISSN 1080-4757 Copyright 1998 The American Physiological Society.
Published in APStracts on 21 September 1998