Li Sha, Huang Huili, Zhang Mengdan, Wang Wei, Xue Shuyin, Gao Ying, Xie Ming, Chen Kesu, Liu Fuming, Chen Long
*National Standard Laboratory of Pharmacology for Chinese Materia Medica, School of Pharmacy, Nanjing University of Chinese Medicine, Nanjing, China; †Department of Respiratory, Inpatient Wards for Senior Cadres, Nanjing General Hospital of Nanjing Military Command Region, Nanjing, China; ‡First Affiliated Hospital, Nanjing University of Chinese Medicine, Nanjing, China; and §Institute of Chinese Medicine of Taizhou China Medical City, Taizhou, China.
J Cardiovasc Pharmacol. 2017 Apr;69(4):236-244. doi: 10.1097/FJC.0000000000000467.
It has been demonstrated that liguzinediol (2,5-dihydroxymethyl-3,6-dimethylpyrazine, LZDO), a derivative of ligustrazine from Ligusticum wallichii Franch, exerts positive inotropy in isolated rat heart mediated by the sarcoplasmic reticulum Ca-ATPase (SERCA2a). Here, we further explore the underlying mechanism of the positive inotropic effect of LZDO in rat hearts. In vivo and ex vivo rat heart experiments, biochemistry, and Western blot techniques were used to analyze the rat heart contractility, and SERCA2a activity, phospholamban (PLB) phosphorylation, and protein phosphatase (PP1 and PP2A) activities in rat left ventricular myocytes, respectively. LZDO (20 mg/kg) significantly increased the inotropy of rat heart in vivo. In isolated rat heart experiments, LZDO (100 μM) restored the decreased inotropy induced by caffeine (0.5 mM); however, calyculin A (4 nM), an inhibitor of PP1 and PP2A, eliminated the inotropic effect of LZDO (100 μM). Moreover, LZDO (1, 10, and 100 μM) significantly enhanced SERCA2a activity and increased the levels of phosphorylated PLB on both serine-16 (Ser-16) and threonine-17 (Thr-17). In addition, LZDO (100 μM) significantly inhibited the activities of PP1 and PP2A. The positive inotropic effects of LZDO on in vivo and ex vivo rat hearts seem to be mediated through inhibition of PP1/PP2A, which may suppress dephosphorylated PLB and enhance SERCA2a activity. LZDO may prove effective in treating heart failure in clinical settings based on its unique biological mechanism.
已证实川芎嗪二醇（2,5 - 二羟甲基 - 3,6 - 二甲基吡嗪，LZDO），一种源自川芎（Ligusticum wallichii Franch）的川芎嗪衍生物，通过肌浆网钙 - ATP酶（SERCA2a）介导，在离体大鼠心脏中发挥正性肌力作用。在此，我们进一步探究LZDO对大鼠心脏正性肌力作用的潜在机制。运用体内和体外大鼠心脏实验、生物化学及蛋白质印迹技术，分别分析大鼠心脏收缩力、SERCA2a活性、磷酸受纳蛋白（PLB）磷酸化水平以及大鼠左心室肌细胞中蛋白磷酸酶（PP1和PP2A）的活性。LZDO（20 mg/kg）显著增强了大鼠心脏在体内的肌力。在离体大鼠心脏实验中，LZDO（100 μM）恢复了由咖啡因（0.5 mM）诱导降低的肌力；然而，PP1和PP2A的抑制剂冈田酸（4 nM）消除了LZDO（100 μM）的肌力作用。此外，LZDO（1、10和100 μM）显著增强了SERCA2a活性，并增加了丝氨酸 - 16（Ser - 16）和苏氨酸 - 17（Thr - 17）位点磷酸化PLB的水平。另外，LZDO（100 μM）显著抑制了PP1和PP2A的活性。LZDO对体内和体外大鼠心脏的正性肌力作用似乎是通过抑制PP1/PP2A介导的，这可能抑制了去磷酸化的PLB并增强了SERCA2a活性。基于其独特的生物学机制，LZDO在临床治疗心力衰竭中可能被证明是有效的。
