Pharmacological potentiation of natriuretic peptide limits polymorphonuclear neutrophil-vascular cell interactions.
OBJECTIVE
Activated polymorphonuclear neutrophils (PMNs) are the main source of circulating neutral endopeptidase (NEP). We tested the hypothesis that NEP inhibition could potentiate the effect of atrial natriuretic peptide (ANP) on PMN-vascular cell interactions in vitro.


RESULTS
ANP alone and its potentiation by retrothiorphan, the NEP inhibitor, significantly inhibited superoxide, lysozyme, and matrix metalloproteinase (MMP)-9 release by N-formyl-Met-Leu-Phe-stimulated PMNs. Activated PMNs degraded exogenous ANP, which was prevented by NEP inhibition. Hypoxia significantly increased the adhesion of PMNs to endothelial cells and their subsequent MMP-9 release by 60% and 150%, respectively (P<0.01). ANP and its potentiation by retrothiorphan limited PMN adhesion to hypoxic endothelial cells and thus decreased their MMP-9 release (P<0.01). Smooth muscle cells (SMCs) incubated with conditioned medium of N-formyl-Met-Leu-Phe-stimulated PMNs exhibited morphological and biochemical changes characteristic of apoptosis (terminal deoxynucleotidyl transferase-mediated dUTP nick end-labeling positivity, nuclear condensation/fragmentation, poly ADP-ribose polymerase cleavage, and DNA laddering). SMC detachment and subsequent apoptosis could be related to leukocyte elastase-induced pericellular proteolysis, inasmuch as both events are inhibited by elastase inhibitors. ANP and its potentiation by retrothiorphan were able to limit elastase release, fibronectin degradation, and SMC apoptosis.


CONCLUSIONS
ANP potentiation by NEP inhibition could limit PMN activation and its consequences on vascular cells.
Mtairag
El Mostafa
el M
U460 INSERM CHU X, Cardiovascular Remodeling, Paris, France.
Houard
Xavier
X
Rais
Samira
S
Pasquier
Catherine
C
Oudghiri
Mounia
M
Jacob
Marie-Paule
MP
Meilhac
Olivier
O
Michel
Jean-Baptiste
JB
D009320:Atrial Natriuretic Factor / Q000378:metabolism / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D002450:Cell Communication / Q000187:drug effects* / Q000502:physiology; D015550:Cell Degranulation / Q000187:drug effects / Q000502:physiology; D017077:Culture Media, Conditioned / Q000494:pharmacology; D004357:Drug Synergism; D004730:Endothelium, Vascular / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005353:Fibronectins / Q000378:metabolism; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology; D019272:Leukocyte Elastase / Q000378:metabolism; D020780:Matrix Metalloproteinase 9 / Q000378:metabolism; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism*; D015260:Neprilysin / Q000037:antagonists & inhibitors / Q000378:metabolism; D018375:Neutrophil Activation / Q000187:drug effects / Q000502:physiology; D009504:Neutrophils / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism* / Q000473:pathology; D016897:Respiratory Burst / Q000187:drug effects / Q000502:physiology; D015244:Thiorphan / Q000031:analogs & derivatives* / Q000494:pharmacology; D014471:Umbilical Veins / Q000166:cytology
D017077:Culture Media, Conditioned; D004791:Enzyme Inhibitors; D005353:Fibronectins; C072559:retrothiorphan; D009320:Atrial Natriuretic Factor; D015244:Thiorphan; D019272:Leukocyte Elastase; D015260:Neprilysin; D020780:Matrix Metalloproteinase 9