title: The mechanism of anti-platelet activity of davallialactone: involvement of intracellular calcium ions, extracellular signal-regulated kinase 2 and p38 mitogen-activated protein kinase.
abstract: This study was designed to investigate the effect of davallialactone, which was isolated from the mushroom Inonotus xeranticus, on platelet aggregation induced by collagen, thrombin and ADP. We found that davallialactone dose-dependently inhibited platelet aggregation that was stimulated either by collagen (2.5 microg/ml), a potent ligand of integrin alpha2beta1 and glycoprotein VI, or by thrombin (0.1U/ml), a potent agonist of the protease-activated receptors (PARs) PAR1 and PAR3. In addition, davallialactone inhibited platelet aggregation induced by ADP, an agonist of P2Y receptor. To understand the mechanism of anti-platelet activity, we determined whether davallialactone affected the downstream signaling in collagen-activated platelets. Using the fura-2/AM fluorometric assay, we found that davallialactone dose-dependently inhibited intracellular calcium concentration levels ([Ca2+]i). Moreover, davallialactone inhibited the phosphorylation of extracellular signal-regulated protein kinase (ERK)-2 and p38 mitogen-activated protein kinase (MAPK), in a dose-dependent manner. The tyrosine phosphorylation of 60 and 85kDa proteins, which were activated by collagen, were differentially inhibited by davallialactone. Taken together, these data suggest that davallialactone may have potential anti-platelet aggregation activity via suppression of intracellular downstream signaling pathways.
authors.affiliation: Laboratory of Veterinary Physiology and Signaling, College of Veterinary Medicine, Kyungpook National University, Daegu 702-701, Republic of Korea.
authors.forename: Sung Dae
authors.initials: SD
authors.lastname: Kim
authors.forename: In-Kyoung
authors.initials: IK
authors.lastname: Lee
authors.forename: Whi Min
authors.initials: WM
authors.lastname: Lee
authors.forename: Jae Youl
authors.initials: JY
authors.lastname: Cho
authors.forename: Hwa Jin
authors.initials: HJ
authors.lastname: Park
authors.forename: Jae-Wook
authors.initials: JW
authors.lastname: Oh
authors.forename: Seung Chun
authors.initials: SC
authors.lastname: Park
authors.forename: Sang Keun
authors.initials: SK
authors.lastname: Kim
authors.forename: Yi Seong
authors.initials: YS
authors.lastname: Kwak
authors.forename: Bong-Sik
authors.initials: BS
authors.lastname: Yun
authors.forename: Man Hee
authors.initials: MH
authors.lastname: Rhee
mesh_terms: D000244:Adenosine Diphosphate / Q000378:metabolism; D000818:Animals; D001792:Blood Platelets / Q000187:drug effects* / Q000201:enzymology / Q000378:metabolism; D020013:Calcium Signaling / Q000187:drug effects*; D003094:Collagen / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D007783:Lactones / Q000494:pharmacology*; D020935:MAP Kinase Signaling System / Q000187:drug effects*; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism*; D010766:Phosphorylation; D019000:Phosphotyrosine / Q000378:metabolism; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D051381:Rats; D013917:Thrombin / Q000378:metabolism; D048051:p38 Mitogen-Activated Protein Kinases / Q000378:metabolism*
chemical_list: D007783:Lactones; D010975:Platelet Aggregation Inhibitors; C068766:davallialactone; D019000:Phosphotyrosine; D000244:Adenosine Diphosphate; D003094:Collagen; D019950:Mitogen-Activated Protein Kinase 1; D048051:p38 Mitogen-Activated Protein Kinases; D013917:Thrombin