PMID: 8950790Nov 1, 1996Paper

Thrombin-activated human platelets release two NAP-2 variants that stimulate polymorphonuclear leukocytes

Thrombosis and Haemostasis
P PiccardoniC Cerletti

Abstract

Thrombin-activated human platelets release substance(s) of a proteic nature which induce an increase in the intracellular calcium concentration in polymorphonuclear leukocytes (PMN). Aim of this study was to characterize the platelet released product(s) responsible for PMN stimulation. PMN-stimulating activity was isolated from platelet supernatant by FPLC and HPLC. The N-terminal sequence analysis revealed that the purified fractions consisted in 90% of a peptide of 73 amino acids and in 10% of a peptide of 74 amino acids; both are truncated forms of the connective tissue-activating peptide III (CTAP-III), a platelet alpha-granule product, and have 3 and 4 additional amino acids at the N-terminus compared with the neutrophil-activating peptide 2 (NAP-2): Asp-Leu-Tyr and Ser-Asp-Leu-Tyr, respectively. Treatment of platelet supernatant (previously depleted of PMN-activating nucleotides) with Affi-gel heparin resulted in the disappearance of PMN-stimulating effects, suggesting that NAP-2 variants, which are heparin-binding proteins, account for ATP-independent PMN-stimulating activity of the supernatant. Cross-desensitization between rNAP-2 and the platelet supernatant and inhibition by the anti-NAP-2 antibody are in agreement wi...Continue Reading

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