title: Delineation of Platelet Activation Pathway of Scutellarein Revealed Its Intracellular Target as Protein Kinase C.
abstract: Erigeron breviscapus has been widely used in traditional Chinese medicine (TCM) and its total flavonoid component is commonly used to treat ischemic stroke, coronary heart disease, diabetes and hypertension. Scutellarin is the major ingredient of E. breviscapus and scutellarein is one of the main bioactive metabolites of scutellarin in vivo, but the latter's pharmacological activities have not been fully characterized. Provided evidence that could inhibit platelet aggregation, the effect of scutellarein on rat washed platelets and its underlying mechanisms were evaluated in our research. Scutellarein inhibited platelet adhesion and aggregation induced by multiple G protein coupled receptor agonists such as thrombin, U46619 and ADP, in a concentration-dependent manner. Furthermore, the mild effect of scutellarein on intracellular Ca(2+) mobilization and cyclic AMP (cAMP) level was observed. On the other hand, the role of scutellarein as potential protein kinase C (PKC) inhibitor was confirmed by PKC activity analysis and molecular docking. The phorbol myristate acetate-induced platelets aggregation assay with or without ADP implied that the scutellarein takes PKC(s) as its primary target(s), and acts on it in a reversible way. Finally, scutellarein as a promising agent exhibited a high inhibition effect on ADP-induced platelet aggregation among its analogues. This study clarifies the PKC-related signaling pathway involved in antiplatelet action of scutellarein, and may be beneficial for the treatment of cardiovascular diseases.
authors.affiliation: Tianjin State Key Laboratory of Modern Chinese Medicine, Tianjin University of Traditional Chinese Medicine.
authors.forename: Xiaoxuan
authors.initials: X
authors.lastname: Tian
authors.forename: Lianying
authors.initials: L
authors.lastname: Chang
authors.forename: Guangyin
authors.initials: G
authors.lastname: Ma
authors.forename: Taiyi
authors.initials: T
authors.lastname: Wang
authors.forename: Ming
authors.initials: M
authors.lastname: Lv
authors.forename: Zhilong
authors.initials: Z
authors.lastname: Wang
authors.forename: Liping
authors.initials: L
authors.lastname: Chen
authors.forename: Yuefei
authors.initials: Y
authors.lastname: Wang
authors.forename: Xiumei
authors.initials: X
authors.lastname: Gao
authors.forename: Yan
authors.initials: Y
authors.lastname: Zhu
mesh_terms: D000818:Animals; D047310:Apigenin / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D001792:Blood Platelets / Q000187:drug effects*; D002118:Calcium / Q000378:metabolism; D002448:Cell Adhesion / Q000187:drug effects / Q000502:physiology; D000242:Cyclic AMP / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D049919:Erigeron / Q000737:chemistry*; D005340:Fibrinogen / Q000378:metabolism; D007527:Isoenzymes; D008297:Male; D015394:Molecular Structure; D015539:Platelet Activation / Q000187:drug effects / Q000502:physiology*; D010974:Platelet Aggregation / Q000187:drug effects; D064546:Protein Kinase C beta / Q000235:genetics / Q000378:metabolism*; D051571:Protein Kinase C-alpha / Q000235:genetics / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D043562:Receptors, G-Protein-Coupled / Q000819:agonists / Q000378:metabolism
chemical_list: D007527:Isoenzymes; D043562:Receptors, G-Protein-Coupled; D047310:Apigenin; D005340:Fibrinogen; D000242:Cyclic AMP; D064546:Protein Kinase C beta; D051571:Protein Kinase C-alpha; C458179:scutellarein; D002118:Calcium