Protein kinase a activity modulates natriuretic peptide-dependent
cgmp accumulation in renal cells.
Ledoux, S[acute]everine, Jean-Claude Dussaule, Christos
Chatziantoniou, Nicole Ardaillou, Sophie Vandermeersch, and Raymond
Ardaillou.
INSERM 64, H[circumflex]opital Tenon, 75020 Paris, France
APStracts 3:0271C, 1996.
The purpose of this work was to examine whether the level of cAMP
accumulation and protein kinase (PK)?A activity influence atrial
natriuretic factor (ANF)-dependent cGMP production in two renal cell
types?: rabbit cortical vascular smooth muscle cells (RCSMC) and SV
-40 transformed human glomerular visceral epithelial cells (HGVEC
-SV1). H89, a PKA inhibitor, decreased ANF-stimulated cGMP production
in RCSMC in a time- and concentration-dependent manner. ANF
-stimulated cGMP production was markedly inhibited after a prolonged
incubation of 9 and 18 h with 25 [mu]M H89 (52 and 65 %,
respectively) but was not altered after exposure of cells to this
agent during 1 h. H7 and H8, protein kinase inhibitors not selective
for PKA, did not reproduce the effect of H89, even at higher
concentrations (50 and 100 [mu]M). Cycloheximide (10 [mu]M), a
protein synthesis inhibitor, limited the inhibitory effect of H89
although, alone, it did not modify the ANF-stimulated cGMP
production. H89 did not affect cGMP production when it was stimulated
by SIN-1, a nitric oxide donor. Prolonged incubation (18?h) with 8
-bromo cAMP or cholera toxin, an activator of Gs?protein resulting in
adenylate cyclase stimulation, enhanced ANF-dependent cGMP production
by 225?% and 176?%, respectively. This stimulatory effect was blocked
by 25?[mu]M H89. [125I]-ANF binding to RCSMC at 4 degrees C was not
affected by preincubation of the cells with H89. There was a 44?%
decrease in the expression of ANF?C-receptors measured as the 4
-23?C?ANF-displaceable [125I]-ANF binding at 37 degrees C which could
not, however, explain the inhibitory effect of H89 on cGMP
production. Modulation of ANF- and CNP-dependent cGMP production by
H89 and cholera toxin was also found in HGVEC-SV1 with the same
characteristics as in RCSMC. Taken together, these results suggest
that PKA activity controls the function of natriuretic peptide
guanylate cyclase-coupled receptors in the two cell types studied.
PKA-dependent inhibition of a negatively regulatory protein distinct
from the receptor itself seems necessary for a full cGMP response to
occur.
Received 19 July 1995; accepted in final form 8 August 1995,8
August
APS Manuscript Number C437-5.
Article publication pending Am. J. Physiol. (Cell Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 29 August 1996