Hierarchical architecture influences calcium dynamics in engineered cardiac muscle.
Hierarchical architecture influences calcium dynamics in engineered cardiac muscle.
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分层结构影响工程心肌的钙动力学。
DOI：
10.1258/ebm.2010.010239
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发表时间：
2011-03
期刊：
影响因子：
--
通讯作者：
Parker KK
中科院分区：
文献类型：
--
作者：
Pong T;Adams WJ;Bray MA;Feinberg AW;Sheehy SP;Werdich AA;Parker KK
心肌细胞形态和组织结构的改变与心脏的机电功能变化是同步的。虽然已知心脏组织的各向异性结构会影响动作电位的传播，但组织结构的影响及其在调节兴奋-收缩耦合（ECC）中的潜在作用尚不明确。我们假设由细胞外基质（ECM）的空间排列引起的心肌细胞形状和方向的变化会影响ECC。为了验证这一假设，我们分离并培养了新生大鼠心室心肌细胞，在不同的纤维连接蛋白微模式下，它们自我组织成不同程度的各向异性组织。然后，我们通过测量细胞宽高比、心肌细胞面积、核密度和细胞骨架f -肌动蛋白排列程度，测量了这些工程心肌组织在几个层次维度上的形态学特征。我们发现，与各向同性组织相比，各向异性组织的细胞纵横比增加，核密度增加，肌细胞面积减少，肌动蛋白排列差异较小。为了了解组织结构如何影响心脏功能，我们通过表征电节奏组织的[Ca2+]i -频率关系，研究了各向异性对细胞内钙（[Ca2+]i）动力学的作用。与各向同性组织相比，各向异性组织在[Ca2+]i瞬态、舒张基线[Ca2+]i水平降低和每个心动周期的[Ca2+]i内流方面表现出显著差异。这些结果表明，ECM信号在细胞和亚细胞水平上影响组织结构并调节ECC。
Changes in myocyte cell shape and tissue structure are concurrent with changes in electromechanical function in both the developing and diseased heart. While the anisotropic architecture of cardiac tissue is known to influence the propagation of the action potential, the influence of tissue architecture and its potential role in regulating excitation–contraction coupling (ECC) are less well defined. We hypothesized that changes in the shape and the orientation of cardiac myocytes induced by spatial arrangement of the extracellular matrix (ECM) affects ECC. To test this hypothesis, we isolated and cultured neonatal rat ventricular cardiac myocytes on various micropatterns of fibronectin where they self-organized into tissues with varying degrees of anisotropy. We then measured the morphological features of these engineered myocardial tissues across several hierarchical dimensions by measuring cellular aspect ratio, myocyte area, nuclear density and the degree of cytoskeletal F-actin alignment. We found that when compared with isotropic tissues, anisotropic tissues have increased cellular aspect ratios, increased nuclear densities, decreased myocyte cell areas and smaller variances in actin alignment. To understand how tissue architecture influences cardiac function, we studied the role of anisotropy on intracellular calcium ([Ca2+]i) dynamics by characterizing the [Ca2+]i –frequency relationship of electrically paced tissues. When compared with isotropic tissues, anisotropic tissues displayed significant differences in [Ca2+]i transients, decreased diastolic baseline [Ca2+]i levels and greater [Ca 2+]i influx per cardiac cycle. These results suggest that ECM cues influence tissue structure at cellular and subcellular levels and regulate ECC.