title: Triflamp, a snake venom metalloproteinase, reduces neutrophil-platelet adhesion through proteolysis of PSGL-1 but not glycoprotein Ib alpha.
abstract: Triflamp, a metalloproteinase isolated from Trimeresurus flavo-viridis, inhibits heterotypic adhesion between platelets and neutrophils. Coincubation studies demonstrate that direct interaction of triflamp with neutrophils is sufficient to inhibit the formation of neutrophil-platelet complexes. Its anti-adhesive effect is in a concentration- and incubation time-dependent manner. Triflamp reduces the expression of P-selectin glycoprotein ligand-1 (PSGL-1) on neutrophils and glycoprotein (GP) Ibalpha on platelets as probed by flow cytometry and Western blot. Moreover, triflamp disrupts P-selectin-mediated adhesion by cleaving PSGL-1 from the neutrophil surface. There are obvious differences regarding PSGL-1 proteolysis by triflamp and cathepsin G. Besides the NH2-terminus of PSGL-1, other sites are truncated by triflamp. The inhibitory effect of triflamp on PSGL-1 expression was prevented by pretreatment with a metalloproteinase inhibitor, phenanthroline. However, triflamp-treated platelets fully keep the ability for binding to PAF- or fMLP-stimulated neutrophils. Our results indicate that degradation of platelet GPIb alpha by triflamp does not interfere with neutrophil-platelet adhesion. Its effect on neutrophil PSGL-1 appears to be a critical factor for its inhibition on neutrophil-platelet interaction.
authors.affiliation: Department of Pharmacology, College of Medicine, National Taiwan University, Taipei, Taiwan.
authors.forename: Yu-Lun
authors.initials: YL
authors.lastname: Tseng
authors.forename: Chia-Jung
authors.initials: CJ
authors.lastname: Lee
authors.forename: Chun-Chieh
authors.initials: CC
authors.lastname: Hsu
authors.forename: Tur-Fu
authors.initials: TF
authors.lastname: Huang
mesh_terms: D001792:Blood Platelets / Q000166:cytology*; D056649:Cathepsin G; D002403:Cathepsins / Q000494:pharmacology; D002448:Cell Adhesion / Q000187:drug effects; D003435:Crotalid Venoms / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D006801:Humans; D008562:Membrane Glycoproteins / Q000378:metabolism*; D045726:Metalloproteases / Q000378:metabolism* / Q000494:pharmacology; D009504:Neutrophils / Q000166:cytology*; D019007:P-Selectin / Q000378:metabolism; D019038:Platelet Glycoprotein GPIb-IX Complex / Q000378:metabolism*; D012697:Serine Endopeptidases / Q000494:pharmacology
chemical_list: D003435:Crotalid Venoms; D008562:Membrane Glycoproteins; D019007:P-Selectin; C084882:P-selectin ligand protein; D019038:Platelet Glycoprotein GPIb-IX Complex; D002403:Cathepsins; D045726:Metalloproteases; C492474:triflamp, Trimeresurus flavoviridis; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G