Inherited human gp91phox deficiency is associated with impaired isoprostane formation and platelet dysfunction.

Abstract

OBJECT:

Platelet isoprostane 8-ISO-prostaglandin F2α (8-iso-PGF2α), a proaggregating molecule, is believed to derive from nonenzymatic oxidation of arachidonic acid. We hypothesized that NADPH is implicated in isoprostane formation and platelet activation.

METHODS AND RESULTS:

We studied 8-iso-PGF2α in platelets from 8 male patients with hereditary deficiency of gp91(phox), the catalytic subunit of NADPH oxidase, and 8 male controls. On stimulation, platelets from controls produced 8-iso-PGF2α, which was inhibited -8% by aspirin and -58% by a specific inhibitor of gp91(phox). Platelets from patients with gp91(phox) hereditary deficiency had normal thromboxane A(2) formation but marked 8-iso-PGF2α reduction compared with controls. In normal platelets incubated with a gp91(phox) inhibitor or with SQ29548, a thromboxane A(2)/isoprostane receptor inhibitor, platelet recruitment, an in vitro model of thrombus growth, was reduced by 44% and 64%, respectively; a lower effect (-17%) was seen with aspirin. Moreover, thrombus formation under shear stress (blood perfusion at the wall shear rate of 1500 s(-1)) was reduced in samples in which isoprostane formation was inhibited by NADPH oxidase inhibitors. In gp91(phox)-deficient patients, agonist-induced platelet aggregation was within the normal range, whereas platelet recruitment was reduced compared with controls. Incubation of platelets from gp91(phox)-deficient patients with 8-iso-PGF2α dose-dependently (1 to 100 pmol/L) increased platelet recruitment by mobilizing platelet Ca(2+) and activating gpIIb/IIIa; a further increase in platelet recruitment was detected by platelet coincubation with l-NAME, an inhibitor of NO synthase.

CONCLUSIONS:

This study provides the first evidence that platelet 8-iso-PGF2α maximally derives from gp91(phox) activation and contributes to platelet recruitment via activation of gpIIb/IIIa.

• Authors: Pasquale Pignatelli, Roberto Carnevale, Serena Di Santo, Simona Bartimoccia, Valerio Sanguigni, Luisa Lenti, Andrea Finocchi, Loredana Mendolicchio, Anna Rosa Soresina, Alessandro Plebani, Francesco Violi
• Journal: Arteriosclerosis, thrombosis, and vascular biology (Arterioscler Thromb Vasc Biol) Vol. 31 Issue 2 Pg. 423-34 (Feb 2011) ISSN: 1524-4636 [Electronic] United States
• PMID: 21071703 (Publication Type: Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Enzyme Inhibitors
• Isoprostanes
• Membrane Glycoproteins
• Platelet Aggregation Inhibitors
• Platelet Glycoprotein GPIIb-IIIa Complex
• 8-epi-prostaglandin F2alpha
• NADP
• Dinoprost
• Nitric Oxide Synthase
• CYBB protein, human
• NADPH Oxidase 2
• NADPH Oxidases
• Aspirin
• Calcium
• NG-Nitroarginine Methyl Ester

Topics

• Adult
• Aspirin (pharmacology)
• Blood Platelets (cytology, drug effects, metabolism)
• Calcium (metabolism)
• Case-Control Studies
• Deficiency Diseases (metabolism, pathology)
• Dinoprost (analogs & derivatives, pharmacology)
• Dose-Response Relationship, Drug
• Enzyme Inhibitors (pharmacology)
• Humans
• Isoprostanes (metabolism)
• Male
• Membrane Glycoproteins (antagonists & inhibitors, deficiency, genetics)
• NADP (metabolism)
• NADPH Oxidase 2
• NADPH Oxidases (antagonists & inhibitors, deficiency, genetics)
• NG-Nitroarginine Methyl Ester (pharmacology)
• Nitric Oxide Synthase (antagonists & inhibitors)
• Platelet Aggregation Inhibitors (pharmacology)
• Platelet Glycoprotein GPIIb-IIIa Complex (metabolism)