title: Scutellarin's Cardiovascular Endothelium Protective Mechanism: Important Role of PKG-Iα.
abstract: Scutellarin (SCU), a flavonoid glycoside compound, has been successfully used in clinic for treatment of ischemic diseases in China. In this report, we checked the effects of SCU on endothelium dysfunction (ED) of coronary artery (CA) against myocardial ischemia reperfusion (MIR) injury in vivo. The involvement of PKG-Iα was further studied using cultured endothelial cells subjected to hypoxia reoxygenation (HR) injury in vitro. In rat MIR model, SCU (45 and 90 mg/kg, iv) significantly reduced ischemic size and restored the endothelium-dependent vasodilation of isolated CA rings. PKG inhibitor Rp-8-Br-cGMP (50 μg/kg, iv) could ameliorate the protective effects of SCU. Increase in phosphorylation of vasodilator-stimulated phosphoprotein (VASP), a main substrate of PKG, at Ser 239 was observed in both heart tissue and serum of SCU-treated animals. In cultured human cardiac microvascular endothelial cells (HCMECs), SCU (1 and 10 μM) dose-dependently protected cell viability and increased the mRNA and protein level of PKG-Iα against HR injury. The activity of PKG was also increased by SCU treatment. The activation of PKG-1α was then studied using targeted proteomic analysis (MRM-MS) checking the phosphorylation state of the autophosphorylation domain (aa42-94). Significant decrease in phosphorylation of PKG-Iα at Ser50, Ser72, Ser89 was induced by HR injury while SCU treatment significantly increased the phosphorylation of PKG-Iα, not only at Ser50, Ser72 and Ser89, but also at Ser44 and Thr58 (two novel phosphorylation domains). Our results demonstrate PKG-Iα might play an important role in the protective effects of SCU on ED against MIR injury.
authors.affiliation: School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, China; Department of Cardiology, First Affiliated Hospital of Kunming Medical University, Kunming, China.
authors.forename: Lin
authors.initials: L
authors.lastname: Li
authors.affiliation: School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, China; Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Li
authors.affiliation: School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Chen
authors.affiliation: School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, China.
authors.forename: Jian
authors.initials: J
authors.lastname: Yang
authors.affiliation: School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, China.
authors.forename: Jiaxun
authors.initials: J
authors.lastname: Li
authors.affiliation: School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, China.
authors.forename: Na
authors.initials: N
authors.lastname: Hu
authors.affiliation: School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, China.
authors.forename: Yang
authors.initials: Y
authors.lastname: Li
authors.affiliation: Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Dongmei
authors.initials: D
authors.lastname: Zhang
authors.affiliation: Department of Cardiology, First Affiliated Hospital of Kunming Medical University, Kunming, China.
authors.forename: Tao
authors.initials: T
authors.lastname: Guo
authors.affiliation: Shanghai Institute of Materia Medica, Chinese Academy of Sciences, Shanghai, China.
authors.forename: Xuan
authors.initials: X
authors.lastname: Liu
authors.affiliation: School of Pharmaceutical Science & Yunnan Key Laboratory of Pharmacology for Natural Products, Kunming Medical University, Kunming, China.
authors.forename: Weimin
authors.initials: W
authors.lastname: Yang
mesh_terms: D000818:Animals; D047310:Apigenin / Q000494:pharmacology* / Q000627:therapeutic use; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000187:drug effects / Q000378:metabolism; D062965:Cyclic GMP-Dependent Protein Kinase Type I / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004730:Endothelium, Vascular / Q000187:drug effects* / Q000378:metabolism; D005965:Glucuronates / Q000494:pharmacology* / Q000627:therapeutic use; D006801:Humans; D017202:Myocardial Ischemia / Q000188:drug therapy* / Q000378:metabolism; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy* / Q000378:metabolism; D010766:Phosphorylation / Q000187:drug effects; D020011:Protective Agents / Q000494:pharmacology* / Q000627:therapeutic use; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D005965:Glucuronates; D020011:Protective Agents; C484876:scutellarin; D047310:Apigenin; D062965:Cyclic GMP-Dependent Protein Kinase Type I