title: Interference of neutrophil-platelet interaction by YC-1: a cGMP-dependent manner on heterotypic cell-cell interaction.
abstract: N-Formyl-Met-Leu-Phe (fMLP) activated neutrophils and then induced neutrophil-platelet complex formation in co-incubation condition. In addition, fMLP induce intracellular calcium mobilization in platelets, only when it is incubated along with neutrophils. This data established that fMLP-stimulated neutrophils activate platelets. 9E1, a monoclonal antibody of P-selectin, significantly blocks the formation of neutrophil-platelet complex induced by fMLP, indicating the involvement of P-selectin in the neutrophil-platelet complex formation. 3-(5'-hydroxymethyl-2'-furyl-1-benzylindazole (YC-1), an unique nitric oxide-independent activator of soluble guanylate cyclase, was evaluated for its effect on neutrophil-platelet complex. YC-1 inhibits fMLP-induced neutrophil-platelet complex formation in a concentration-dependent manner with an IC50 value of 15.3+/-3.5 microM. However, this effect of YC-1 is partially reversed by pre-treatment of 1H-(1,2,4)oxadiazolo[4,3-a]quinozalin-1-one (ODQ; 10 microM), which is a soluble guanylate cyclase inhibitor. Pre-treatment of either neutrophils or platelets with YC-1 (50 microM) prevent the fMLP-induced neutrophil-platelet complex formation, indicating that YC-1 could potentially exert its effects individually on either neutrophils or platelets alone. Cathepsin G released from fMLP-stimulated neutrophil activates the nearby platelets. YC-1 was also shown to inhibit this release of cathepsin G in a concentration-dependent manner. The IC50 value was 6.2+/-0.2 microM. This inhibitory effect of YC-1 on cathepsin G release is reversed by ODQ (10 microM) and a protein kinase G inhibitor [1-oxo-9.12-epoxy-1H-diindolo[1,2,3-fg:3',2',1'-kl]pyrrolo[3,4-l][1,6]benzodiazocine-10-carbooxylic acid methyl ester (KT5835); 1 microM]. YC-1 inhibits cathepsin G-induced P-selectin expression on human platelet at the IC50 value of 32.5+/-2.6 microM. A further study showed that YC-1 inhibits fMLP-induced neutrophil-platelet complex formation in whole blood at the IC50 value of 35.8+/-8.1 microM in a concentration-dependent manner. According to these data, it was hypothesized that fMLP stimulates neutrophils to release cathepsin G, which subsequently activates the nearby platelets, creating neutrophil-platelet complexes. YC-1 inhibits fMLP-induced neutrophil from releasing cathepsin G via a cGMP-dependent pathway. This inhibitory effect of YC-1 on cathepsin G release is a major mechanism for affecting fMLP-induced neutrophil-platelet complex. YC-1's inhibition P-selectin expression on platelet may potentiate its effects. These inhibitory effects may contribute to the inhibition of neutrophil-platelet complex formation in whole blood.
authors.affiliation: Graduate Institute of Natural Products, College of Medicine Chang Gung University No 259 Wen-Hwa 1st Road, Kwei-Shan, Tao-Yuan county, 333 Taiwan, Republic of China. liaoch@mail.cgu.edu.tw
authors.forename: Chang-Hui
authors.initials: CH
authors.lastname: Liao
authors.forename: Jun-Ting
authors.initials: JT
authors.lastname: Cheng
authors.forename: Che-Ming
authors.initials: CM
authors.lastname: Teng
mesh_terms: D000328:Adult; D000906:Antibodies / Q000494:pharmacology; D001792:Blood Platelets / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D002118:Calcium / Q000097:blood / Q000378:metabolism; D056649:Cathepsin G; D002403:Cathepsins / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects; D002450:Cell Communication / Q000187:drug effects*; D006152:Cyclic GMP / Q000097:blood / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000494:pharmacology; D005260:Female; D005434:Flow Cytometry; D006162:Guanylate Cyclase / Q000037:antagonists & inhibitors; D006801:Humans; D007191:Indazoles / Q000494:pharmacology*; D042541:Intracellular Space / Q000187:drug effects / Q000378:metabolism; D008297:Male; D009240:N-Formylmethionine Leucyl-Phenylalanine / Q000494:pharmacology; D009504:Neutrophils / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010069:Oxadiazoles / Q000494:pharmacology; D019007:P-Selectin / Q000276:immunology / Q000378:metabolism; D011810:Quinoxalines / Q000494:pharmacology; D012697:Serine Endopeptidases / Q000378:metabolism; D013997:Time Factors
chemical_list: C095284:1H-(1,2,4)oxadiazolo(4,3-a)quinoxalin-1-one; D000906:Antibodies; D004791:Enzyme Inhibitors; D007191:Indazoles; D010069:Oxadiazoles; D019007:P-Selectin; D011810:Quinoxalines; C090937:3-(5'-hydroxymethyl-2'-furyl)-1-benzylindazole; D009240:N-Formylmethionine Leucyl-Phenylalanine; D002403:Cathepsins; D012697:Serine Endopeptidases; C534094:CTSG protein, human; D056649:Cathepsin G; D006162:Guanylate Cyclase; D006152:Cyclic GMP; D002118:Calcium