Calcitriol (1,25-dihydroxyvitamin D3) increases L-type calcium current via protein kinase A signaling and modulates calcium cycling and contractility in isolated mouse ventricular myocytes
Calcitriol (1,25-dihydroxyvitamin D3) increases L-type calcium current via protein kinase A signaling and modulates calcium cycling and contractility in isolated mouse ventricular myocytes
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DOI：
10.1016/j.hrthm.2016.12.013
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发表时间：
2017-03-01
期刊：
影响因子：
5.5
通讯作者：
Delgado, Carmen
中科院分区：
文献类型：
--
作者：
Tamayo, Maria;Manzanares, Esmeralda;Delgado, Carmen
骨化三醇是维生素D的生物活性代谢物，通过与核维生素D受体（VDR）相互作用来诱导基因组应答。骨化三醇还可能通过质膜相关的VDR诱导快速反应，包括第二信使的激活和电压依赖性通道的调节。VDR在心肌细胞中表达，但参与骨化三醇在心脏中的快速反应的分子和细胞机制尚不清楚。目的：本研究的目的是分析骨化三醇对心室肌细胞l型钙通道、细胞内Ca2+ ([Ca2+]i)瞬态和细胞收缩性的快速非基因组效应。方法采用全细胞膜片湿法记录l型钙电流（I-caL），共聚焦显微镜研究全局[Ca2+]；电刺激引起的瞬变和小鼠心室肌细胞缩短给药或骨化三醇。在一些实验中，I-ca - L是用穿孔贴片阻尼技术记录的。结果骨化三醇处理心肌细胞诱导I-caL密度呈浓度依赖性增加（最大有效浓度的一半(EC50) = 0.23 nM），峰值[Ca2+]显著增加；瞬态和细胞收缩。蛋白激酶A （PKA）抑制剂KT-5720预处理心肌细胞可阻止骨化三醇对I-caL的影响，而β -肾上腺素能模拟剂心得安则不能。骨化三醇对VDR敲除小鼠肌细胞中I-cal的影响不存在。结论骨化三醇诱导小鼠心室肌细胞的快速反应，涉及vdr - pka依赖性的（IcaL）密度增加，增强[Ca2+]；瞬态和缩写。
BACKGROUND Calcitriol, the bioactive metabolite of vitamin D, exerts its effects through interaction with the nuclear vitamin D receptor (VDR) to induce genomic responses. Calcitriol may also induce rapid responses via plasma membrane-associated VDR, involving the activation of second messengers and modulation of voltage-dependent channels. VDR is expressed in cardiomyocytes, but the molecular and cellular mechanisms involved in the rapid responses of calcitriol in the heart are poorly understood.OBJECTIVE The aim of the present study was to analyze the rapid nongenomic effect of calcitriol on L-type calcium channels, intracellular Ca2+ ([Ca2+]i) transients, and cell contractility in ventricular myocytes.METHODS We used the whole-cell patch-damp technique to record L-type calcium current (I-caL) and confocal microscopy to study global [Ca2+]; transients evoked by electrical stimulation and cell shortening in adult mouse ventricular myocytes treated with vehicle or with calcitriol. In some experiments, I-ca L was recorded using the perforated patch-damp technique.RESULTS Calcitriol treatment of cardiomyocytes induced a concentration -dependent increase in I-caL density (Half maximal effective concentration (EC50) = 0.23 nM) and a significant increase in peak [Ca2+]; transients and cell contraction. The effect of calcitriol on I-caL was prevented by pretreatment of cardiomyocytes with the protein kinase A (PKA) inhibitor KT-5720 but not with the beta-adrenergic Mocker propranolol. The effect of calcitriol on I-cal was absent in myocytes isolated from VDR knockout mice.CONCLUSION Calcitriol induces a rapid response in mouse ventricular myocytes that involves a VDR-PKA-dependent increase in (IcaL) density, enhancing [Ca2+]; transients and contraction.