Contractile activity modulates myosin heavy chain-beta expression in neonatal rat heart cells.
Contractile activity modulates myosin heavy chain-beta expression in neonatal rat heart cells.
复制标题
收缩活性调节新生大鼠心脏细胞中肌球蛋白重链β的表达。
DOI：
10.1152/ajpheart.1991.261.4.h1067
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发表时间：
1991
期刊：
影响因子：
--
通讯作者：
Engelmann,GL
中科院分区：
文献类型：
--
作者：
Samarel,AM;Engelmann,GL
为了确定自发收缩活动是否影响培养的新生大鼠心脏细胞中肌球蛋白重链同工酶的表达，通过胶原酶消化从2日龄大鼠幼仔中分离心室肌细胞，并在存在和不存在维拉帕米（10 μ M）、KCl（50 mM）或产生收缩停滞的二氢吡啶受体拮抗剂的情况下培养24-96 h。自发收缩活动的抑制与总肌球蛋白重链（MHC）含量和合成率的显着降低。MHC同工酶的电泳分析表明，MHC-β蛋白迅速从被捕细胞中消失，而MHC-α同工酶水平受影响较小。与这些蛋白质变化相关，静止细胞中MHC-β的mRNA转录水平显着降低，而其他几种收缩蛋白基因的mRNA转录水平受到的影响相对较小。收缩活性和MHC-β表达的抑制在去除阻滞剂后是可逆的。此外，可以通过用佛波醇12-肉豆蔻酸酯13-乙酸酯直接激活蛋白激酶C来防止被阻滞的心肌细胞中MHC-β mRNA水平的降低（而不恢复收缩活性）。相反，用staurosporine（一种选择性蛋白激酶C抑制剂）处理，搏动细胞中的MHC-β mRNA水平降低。因此，收缩停滞（由L-通道阻断或膜去极化产生）通过翻译前机制抑制培养的新生大鼠心脏细胞中MHC-β的积累。这些效应可能是对信号系统调节的反应，信号系统涉及通过蛋白激酶C转导的机械“拉伸”。
To determine whether spontaneous contractile activity affected the expression of myosin heavy chain isoenzymes in cultured neonatal rat heart cells, ventricular myocytes were isolated from 2-day-old rat pups by collagenase digestion and cultured for 24-96 h in the presence and absence of verapamil (10 microM), KCl (50 mM), or dihydropyridine receptor antagonists that produced contractile arrest. Inhibition of spontaneous contractile activity was associated with significant reductions in total myosin heavy chain (MHC) content and synthetic rates. Electrophoretic analysis of MHC isoenzymes indicated that MHC-beta protein rapidly disappeared from arrested cells, whereas MHC-alpha isoenzyme levels were less affected. In association with these protein changes, mRNA transcript levels for MHC-beta were markedly reduced in quiescent cells, whereas mRNA transcript levels for several other contractile protein genes were relatively less affected. Inhibition of contractile activity and MHC-beta expression were reversible upon removal of the arresting agents. Furthermore, the decrease in MHC-beta mRNA levels in arrested myocytes could be prevented by direct activation of protein kinase C with phorbol 12-myristate 13-acetate (without restoration of contractile activity). Conversely, MHC-beta mRNA levels in beating cells were reduced by treatment with staurosporine (a selective protein kinase C inhibitor). Thus contractile arrest (produced by either L-channel blockade or membrane depolarization) inhibited the accumulation of MHC-beta in cultured neonatal rat heart cells via a pretranslational mechanism. These effects may occur in response to the modulation of signaling system(s) involving mechanical “stretch” transduced via protein kinase C.