Mechanical strain increases smooth muscle and decreases nonmuscle myosin expression in rat vascular smooth muscle cells
Mechanical strain increases smooth muscle and decreases nonmuscle myosin expression in rat vascular smooth muscle cells
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DOI：
10.1161/01.res.79.5.1046
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发表时间：
1996-11-01
影响因子：
20.1
通讯作者：
Ives, HE
中科院分区：
文献类型：
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作者：
Reusch, P;Wagdy, H;Ives, HE
观察了周期性机械应变(L-Hz)对培养的乳鼠血管平滑肌细胞肌球蛋白重链异构体表达的影响。免疫印迹法鉴定肌球蛋白重链亚型：(1)平滑肌肌球蛋白重链亚型SM-1和SM-2，(2)SM-1，以及(3)非肌肉肌球蛋白重链A和B。在36~72小时的应变反应中，SM-1和SM-2增加4~6倍，而非肌肉肌球蛋白A减少到对照组的30%。非肌肉肌球蛋白B不受菌株的影响。SM-1mRNA在应变12小时后增加两倍至三倍，但此后下降至对照水平。SM-2mRNA几乎检测不到。非肌肉肌球蛋白A基因在应变3h后下降到对照组的50%，然后恢复到对照组水平。由于这些细胞分泌血小板衍生生长因子(PDGF)以响应应变，我们评估了PDGF对肌球蛋白异构体表达的影响。外源PDGF(10 ng/mL)可使SM-1的表达降低35%，使非肌肉肌球蛋白的表达增加一倍，与菌株相反。在细胞中，暴露在含有PDGF-AB中和抗体的菌株中。应变诱导的SM-1的增加是对照组的10倍，非肌肉肌球蛋白A减少到对照组的40%。最后，研究了细胞外基质对应变信号转导的影响。48小时的循环应变使在I型胶原上培养的细胞SM-1增加了两倍，在层粘连蛋白上培养的细胞增加了三倍。在纤维连接蛋白培养的细胞中，菌株不会引起SM-1的增加。因此。通过与基质的特定相互作用感觉到的机械应变可以改变肌球蛋白亚型的表达，使其趋向于更具分化状态的表达。
The effect of cyclic (l-Hz) mechanical strain on expression of myosin heavy chain isoforms was examined in neonatal rat vascular smooth muscle cells cultured on silicone elastomer plates. Myosin heavy chain isoforms were identified by immunoblot using antibodies recognizing (1) smooth muscle myosin heavy chain isoforms SM-1 and SM-2, (2) SM-1 exclusively, and (3) nonmuscle myosin heavy chains A and B. In response to 36 to 72 hours of strain, SM-1 and SM-2 increased by fourfold to sixfold, whereas nonmuscle myosin A decreased to 30% of control. Nonmuscle myosin B was unaffected by strain. SM-1 mRNA increased by twofold to threefold after 12 hours of strain but decreased toward control levels thereafter. SM-2 mRNA was only barely detectable. Nonmuscle myosin A mRNA decreased to 50% of control after 3 hours of strain and then returned to the control level. Since these cells secrete platelet-derived growth factor (PDGF) in response to strain, we assessed the effects of PDGF on myosin isoform expression. Exogenous PDGF (10 ng/mL, decreased SM-1 expression by 35% and increased nonmuscle myosin expression twofold, opposite the effect of strain. In cells, exposed to strain with neutralizing antibodies to PDGF-AB. the strain-induced increase in SM-1 was enhanced 10-fold, and nonmuscle myosin A was reduced to 40% of control. Finally, the effect of extracellular matrix on transduction of the strain signal was studied. Forty-eight hours of cyclic strain increased SM-1 by twofold in cells cultured on collagen type I and threefold in cells cultured on laminin. In fibronectin-cultured cells, strain elicited no increase in SM-1. Thus. mechanical strain, sensed through specific interactions with the matrix can alter myosin isoform expression toward that found in a more differentiated state.