Rhythmic beating of stem cell-derived cardiac cells requires dynamic coupling of electrophysiology and Ca cycling.
Rhythmic beating of stem cell-derived cardiac cells requires dynamic coupling of electrophysiology and Ca cycling.
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DOI：
10.1016/j.yjmcc.2010.09.018
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发表时间：
2011-01
影响因子：
5
通讯作者：
Maltsev VA
中科院分区：
文献类型：
--
作者：
Zahanich I;Sirenko SG;Maltseva LA;Tarasova YS;Spurgeon HA;Boheler KR;Stern MD;Lakatta EG;Maltsev VA
人们对分化胚胎干细胞以设计生物起搏器作为心脏起搏器功能缺陷患者电子起搏器的替代品有着浓厚的兴趣。然而，胚胎干细胞来源的心肌细胞(ESCs)经常表现出节律失常的兴奋。利用钙离子成像和膜片钳技术，我们研究了小鼠胚胎干细胞晚期自发节律动作电位(AP)的产生条件。ESCs的肌浆网(SR)产生自发的、节律性的、小波样的局部钙释放(LCRs)(被兰诺丁、丁卡因或thapsigargin抑制)。L型钙电流(ICIC)引起整体钙释放，耗尽钙含量SR，使LCR振荡器的位相重置。在延迟一段时间后，SR在整个细胞内产生高度同步的多个LCR的自发钙释放。LCR产生内向的Na+/Ca~(2+)交换器(NCX)电流(在无Na+的溶液中不存在)，从而点燃下一个AP。干扰肌浆网钙离子循环(ryanodine、咖啡因、thapsigargin、clecopiazonic acid、BAPTA-AM)、NCX(无钠溶液)或ical(硝苯地平)会导致节律性兴奋或自律性停止。特异性PKA抑制剂PKI抑制cAMP/PKA信号，减少SR钙负荷，显著减少自发LCR(数目、大小和幅度)和节律性AP放电。相反，cAMP增强PKA信号会增加LCR(数量、大小、持续时间)，并将不规则跳动的ESCs转化为有节奏的“起搏样”细胞。磷蛋白抗体选择性激活肌浆网钙泵也可增加肌浆网钙负荷和LCR活性。肌浆网钙负荷和自发节律性LCR是由固有的cAMP/PKA活性驱动的。ICAL同步多个LCR振荡器，导致部分同步的强大的舒张期钙释放和NCx电流。节律性ESC的自动化可以通过增强“偶联”因子来实现，例如cAMP/PKA信号，从而增强SR和肌膜之间的相互作用。
There is an intense interest in differentiating embryonic stem cells to engineer biological pacemakers as an alternative to electronic pacemakers for patients with cardiac pacemaker function deficiency. Embryonic stem cell-derived cardiocytes (ESCs), however, often exhibit dysrhythmic excitations. Using Ca2+ imaging and patch-clamp techniques, we studied requirements for generation of spontaneous rhythmic action potentials (APs) in late-stage mouse ESCs. Sarcoplasmic reticulum (SR) of ESCs generates spontaneous, rhythmic, wavelet-like Local Ca2+Releases (LCRs)(inhibited by ryanodine, tetracaine, or thapsigargin). L-type Ca2+ current (ICaL) induces a global Ca2+ release (CICR), depleting the Ca2+ content SR which resets the phases of LCR oscillators. Following a delay, SR then generates a highly synchronized spontaneous Ca2+ release of multiple LCRs throughout the cell. The LCRs generate an inward Na+/Ca2+ exchanger (NCX) current (absent in Na+-free solution) that ignites the next AP. Interfering with SR Ca2+ cycling (ryanodine, caffeine, thapsigargin, cyclopiazonic acid, BAPTA-AM), NCX (Na+-free solution), or ICaL (nifedipine) results in dysrhythmic excitations or cessation of automaticity. Inhibition of cAMP/PKA signaling by a specific PKA inhibitor, PKI, decreases SR Ca2+ loading, substantially reducing both spontaneous LCRs (number, size, and amplitude) and rhythmic AP firing. In contrast, enhancing PKA signaling by cAMP increases the LCRs (number, size, duration) and converts irregularly beating ESCs to rhythmic “pacemaker-like” cells. SR Ca2+ loading and LCR activity could be also increased with a selective activation of SR Ca2+ pumping by a phospholamban antibody. SR Ca2+ loading and spontaneous rhythmic LCRs are driven by inherent cAMP/PKA activity. ICaL synchronizes multiple LCR oscillators resulting in strong, partially synchronized diastolic Ca2+ release and NCX current. Rhythmic ESC automaticity can be achieved by boosting “coupling” factors, such as cAMP/PKA signaling, that enhance interactions between SR and sarcolemma.
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影响因子：
37.8
作者：
Macia E;Boyden PA
通讯作者：
Boyden PA
影响因子：
5.5
作者：
Hüser, J;Blatter, LA;Lipsius, SL
通讯作者：
Lipsius, SL
影响因子：
20.1
作者：
MATSUDA, JJ;LEE, H;SHIBATA, EF
通讯作者：
SHIBATA, EF
影响因子：
15.9
作者：
Klug, MG;Soonpaa, MH;Field, LJ
通讯作者：
Field, LJ
DOI：
10.1152/ajpheart.01118.2008
发表时间：
2009-03-01
影响因子：
4.8
作者：
Maltsev, Victor A.;Lakatta, Edward G.
通讯作者：
Lakatta, Edward G.