Matrix protein-specific regulation of Cx43 expression in cardiac myocytes subjected to mechanical load
Matrix protein-specific regulation of Cx43 expression in cardiac myocytes subjected to mechanical load
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DOI：
10.1161/01.res.0000158964.42008.a2
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发表时间：
2005-03-18
影响因子：
20.1
通讯作者：
Saffitz, JE
中科院分区：
文献类型：
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作者：
Shanker, AJ;Yamada, K;Saffitz, JE
为了阐明心脏机械转导的机制和确定细胞外基质重塑的影响，我们用天然的I型胶原、纤维连接蛋白或变性的胶原培养新生大鼠的心肌细胞，并对它们进行单轴、脉冲式拉伸。用共聚焦显微镜和免疫印迹法检测心脏缝隙连接蛋白Cx43的表达变化。生长在纤维连接蛋白或变性胶原上的细胞比生长在天然胶原上的细胞有更强的Cx43表达。拉伸诱导生长在天然胶原上的细胞的Cx43表达增加近2倍，但在生长在纤维连接蛋白或变性胶原上的细胞没有增加。用含有精氨酸-甘氨酸-天冬氨酸(RGD)基序的多肽在天然胶原上孵育细胞，可上调Cx43的表达，与拉伸诱导的表达相当。用MnCl2非选择性地激活整合素信号也上调了生长在天然胶原上的细胞中Cx43的表达。这种作用可被抗β(1)整合素抗体完全阻断，但不能被抗β(3)整合素抗体阻断。拉伸导致生长在天然胶原蛋白上的细胞中的β(1)整合素免疫荧光信号显著增加，但在生长在纤维连接蛋白或变性胶原蛋白上的细胞中却没有。抗β(1)整合素抗体也可阻断牵张诱导的Cx43表达上调。因此，基质蛋白-心肌细胞之间的相互作用通过机械刺激在天然I型胶原上生长的细胞中启动的β(1)整合素信号，或在纤维连接蛋白或变性胶原上生长的细胞中独立于机械应力的RGD-整合素信号来调节Cx43的表达。细胞外基质成分的变化可能会影响心肌细胞的电偶联。
To elucidate mechanisms responsible for mechanotransduction in the heart and define the effects of remodeling of the extracellular matrix, we cultured neonatal rat ventricular myocytes on native type I collagen, fibronectin, or denatured collagen and subjected them to uniaxial, pulsatile stretch. Changes in expression of the cardiac gap junction protein, Cx43, were measured by confocal microscopy and immunoblotting. Cells grown on fibronectin or denatured collagen exhibited significantly greater Cx43 expression than cells grown on native collagen. Stretch induced a approximate to 2-fold increase in Cx43 expression in cells grown on native collagen but no increase in cells grown on fibronectin or denatured collagen. Incubation of cells on native collagen with a peptide containing the arginine-glycine-aspartate (RGD) motif upregulated Cx43 expression equivalent to that induced by stretch. Nonselective activation of integrin signaling with MnCl2 also upregulated Cx43 expression in cells grown on native collagen. This effect was blocked completely by pretreatment with anti-beta(1) integrin antibody but not by anti-beta(3) integrin antibody. Stretch led to a marked increase in beta(1) integrin immunofluorescent signal in cells grown on native collagen but not in cells grown on fibronectin or denatured collagen. Stretch-induced upregulation of Cx43 was also blocked by anti-beta(1) integrin antibody. Thus, matrix protein-myocyte interactions regulate Cx43 expression via beta(1) integrin signaling initiated by mechanical stimulation in cells grown on native type I collagen, or by RGD-integrin signaling independent of mechanical stress in cells grown on fibronectin or denatured collagen. Changes in the composition of the extracellular matrix may affect electrical coupling in cardiac myocytes.