Cross-bridge cycling gives rise to spatiotemporal heterogeneity of dynamic subcellular mechanics in cardiac myocytes probed with atomic force microscopy
Cross-bridge cycling gives rise to spatiotemporal heterogeneity of dynamic subcellular mechanics in cardiac myocytes probed with atomic force microscopy
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DOI：
10.1152/ajpheart.00427.2009
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发表时间：
2010-03-01
影响因子：
4.8
通讯作者：
Costa, Kevin D.
中科院分区：
文献类型：
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作者：
Azeloglu, Evren U.;Costa, Kevin D.
Azeloglu EU、Costa KD。原子力显微镜观察心肌细胞跨桥循环时动态亚细胞力学的时空异质性。Am J Physiol Heart Circ Physiol 298：H853-H860，2010.首次发表于2009年12月18日; doi：10.1152/ajpheart.00427.2009。为了研究心脏的动态亚细胞力学特性如何与肌动蛋白-肌球蛋白跨桥循环的基本基本过程相关，我们开发了一种新的原子力显微镜弹性成像技术，用于映射分离的自发跳动的新生大鼠心肌细胞的时空刚度。细胞以接近但不等于其收缩频率的速率反复缩进。在400 nm的代表性深度处，所得逐点表观弹性模量的变化以可预测的包络频率在收缩期值26.2 +/- 5.1 kPa和舒张期值7.8 +/- 4.1 kPa之间循环。在细胞探测沿着他们的主轴，时空变化的收缩刚度显示出异质性模式，反映了带状肌节结构的肌原纤维。用blebbistatin治疗消除了收缩活性，并导致6.5 +/- 4.8 kPa的均匀表观模量。这项研究代表了第一个定量的动态力学映射跳动的心肌细胞。该技术提供了一种手段，探索疾病过程和药物治疗对跳动心肌细胞的微观力学影响，提供新的见解，并将亚细胞心脏结构和功能联系起来。
Azeloglu EU, Costa KD. Cross-bridge cycling gives rise to spatiotemporal heterogeneity of dynamic subcellular mechanics in cardiac myocytes probed with atomic force microscopy. Am J Physiol Heart Circ Physiol 298: H853-H860, 2010. First published December 18, 2009; doi:10.1152/ajpheart.00427.2009.-To study how the dynamic subcellular mechanical properties of the heart relate to the fundamental underlying process of actin-myosin cross-bridge cycling, we developed a novel atomic force microscope elastography technique for mapping spatiotemporal stiffness of isolated, spontaneously beating neonatal rat cardiomyocytes. Cells were indented repeatedly at a rate close but unequal to their contractile frequency. The resultant changes in pointwise apparent elastic modulus cycled at a predictable envelope frequency between a systolic value of 26.2 +/- 5.1 kPa and a diastolic value of 7.8 +/- 4.1 kPa at a representative depth of 400 nm. In cells probed along their major axis, spatiotemporal changes in systolic stiffness displayed a heterogeneous pattern, reflecting the banded sarcomeric structure of underlying myofibrils. Treatment with blebbistatin eliminated contractile activity and resulted in a uniform apparent modulus of 6.5 +/- 4.8 kPa. This study represents the first quantitative dynamic mechanical mapping of beating cardiomyocytes. The technique provides a means of probing the micromechanical effects of disease processes and pharmacological treatments on beating cardiomyocytes, providing new insights and relating subcellular cardiac structure and function.