Diltiazem Inhibits Coronary Spasm via Inhibition of Cav1.2 Phosphorylation and Protein Kinase C Activation in a Mouse Model of Coronary Spastic Angina
Diltiazem Inhibits Coronary Spasm via Inhibition of Cav1.2 Phosphorylation and Protein Kinase C Activation in a Mouse Model of Coronary Spastic Angina
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DOI：
10.1536/ihj.20-366
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发表时间：
2021-07-01
影响因子：
1.5
通讯作者：
Tomita, Hirofumi
中科院分区：
文献类型：
--
作者：
Ishida, Yuji;Kitayama, Kazutaka;Tomita, Hirofumi
钙拮抗剂用于冠状动脉痉挛性心绞痛（CSA）治疗。我们先前鉴定了导致CSA患者PLC活性增强的磷脂酶C（PLC）-81基因变体，并通过产生血管平滑肌细胞特异性人变体PLC-81过表达（PLC-TG）小鼠开发了CSA动物模型。本研究以PLC-TG小鼠为模型，探讨CSA的分子机制，并观察钙拮抗剂盐酸地尔硫卓（DL）对CSA的抑制作用。我们用口服DL或三氯噻嗪（TM）（对照）处理PLC-TG和野生型（WT）小鼠2周。在所有5只TM处理的PLC-TG小鼠的心电图上观察到麦角新碱注射诱导的冠状动脉痉挛，但仅在1/5只DL处理的PLC-TG小鼠中观察到。TM处理的PLC-TG小鼠睾丸中电压依赖性钙通道（Cav1.2）磷酸化和蛋白激酶C（PKC）活性增强。DL处理显著抑制Cav1.2磷酸化和PKC活性。尽管用TM处理的WT和PLC-TG小鼠之间的总Cav1.2表达相似，但DL处理显著增加了其在PLC-TG小鼠中的表达。此外，在DL停止后，其表达仍然很高。DL和PKC抑制剂抑制培养的大鼠主动脉平滑肌细胞转染变异PLC-81的乙酰胆碱的细胞内钙反应。这些结果表明，增强PLC活性导致冠状动脉痉挛，可能是通过增强Cav1.2磷酸化和PKC活性，这两者都被DL抑制。DL停药后Cav1.2总表达增强和PKC活性增高可能是钙拮抗剂戒断综合征的重要机制。(Int Heart J 2021; 62：910-918）上标/下标可用
Calcium antagonists are used for coronary spastic angina (CSA) treatment. We previously identified a phospholipase C (PLC) -81 gene variant that results in enhanced PLC activity in patients with CSA and developed a CSA animal model by generating vascular smooth muscle cell-specific human variant PLC -81 overexpression (PLC-TG) mice. In this study, we investigated the molecular mechanism of CSA using the PLC-TG mice and the inhibitory effect of a calcium antagonist, diltiazem hydrochloride (DL). We treated the PLC-TG and wild-type (WT) mice with oral DL or trichlormethiazide (TM) (control) for 2 weeks. Ergometrine injection-induced coronary spasm was observed on the electrocardiogram in all 5 PLC-TG mice treated with TM, but only in 1 of 5 PLC-TG mice treated with DL. Voltage-dependent calcium channel (Cav1.2) phosphorylation and protein kinase C (PKC) activity were enhanced in the aortas of PLC-TG mice treated with TM. DL treatment significantly inhibited Cav1.2 phosphorylation and PKC activity. Although total Cav1.2 expression was similar between WT and PLC-TG mice treated with TM, DL treatment significantly increased its expression in PLC-TG mice. Furthermore, its expression remained high after DL discontinuation. DL and PKC inhibitor suppressed intracellular calcium response to acetylcholine in cultured rat aortic smooth muscle cells transfected with variant PLC -81. These results indicate that enhanced PLC activity causes coronary spasm, presumably via enhanced Cav1.2 phosphorylation and PKC activity, both of which were inhibited by DL. Enhanced total Cav1.2 expression after DL discontinuation and high PKC activity may be an important mechanism underlying the calcium antagonist withdrawal syndrome. (Int Heart J 2021; 62: 910-918)Superscript/Subscript Available