Extracellular stiffness induces contractile dysfunction in adult cardiomyocytes via cell-autonomous and microtubule-dependent mechanisms.
Extracellular stiffness induces contractile dysfunction in adult cardiomyocytes via cell-autonomous and microtubule-dependent mechanisms.
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细胞外刚度通过细胞自主和微管依赖性机制引起成人心肌细胞的收缩功能障碍。
DOI：
10.1007/s00395-022-00952-5
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发表时间：
2022-08-25
影响因子：
9.5
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中科院分区：
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心肌的力学环境对心肌细胞的形态和功能有很强的影响，但对心肌细胞对细胞外硬化的反应的理解仍然不完全。因此，我们采用了一种具有可调刚度的细胞培养基质来定义心肌细胞在没有细胞-细胞相互作用的情况下对临床相关刚度增量的反应。当培养在磁致动的基板上，以模仿患病心肌的刚度，分离的大鼠成年心肌细胞表现出时间依赖性的肌节缩短减少，其特征在于收缩和舒张速度减慢，和钙瞬变的改变。在刚性基质上培养的心肌细胞出现粘弹性和微管脱酪氨酸的增加，与α-微管蛋白脱酪氨酸酶vasohibin-2（Vash 2）的早期增加相关。我们发现，敲低Vash 2足以保持收缩性能以及钙瞬变特性的存在下，细胞外基质硬化。通过过度表达微管蛋白酪氨酸连接酶（TTL）的正交预防脱酪氨酸也能够保持收缩性和钙稳态。这些数据表明，细胞外硬度的病理性增加诱导依赖于α-微管蛋白脱酪氨酸的成体心肌细胞的早期细胞自主重塑。
The mechanical environment of the myocardium has a potent effect on cardiomyocyte form and function, yet an understanding of the cardiomyocyte responses to extracellular stiffening remains incomplete. We therefore employed a cell culture substrate with tunable stiffness to define the cardiomyocyte responses to clinically relevant stiffness increments in the absence of cell–cell interactions. When cultured on substrates magnetically actuated to mimic the stiffness of diseased myocardium, isolated rat adult cardiomyocytes exhibited a time-dependent reduction of sarcomere shortening, characterized by slowed contraction and relaxation velocity, and alterations of the calcium transient. Cardiomyocytes cultured on stiff substrates developed increases in viscoelasticity and microtubule detyrosination in association with early increases in the α-tubulin detyrosinating enzyme vasohibin-2 (Vash2). We found that knockdown of Vash2 was sufficient to preserve contractile performance as well as calcium transient properties in the presence of extracellular substrate stiffening. Orthogonal prevention of detyrosination by overexpression of tubulin tyrosine ligase (TTL) was also able to preserve contractility and calcium homeostasis. These data demonstrate that a pathologic increment of extracellular stiffness induces early, cell-autonomous remodeling of adult cardiomyocytes that is dependent on detyrosination of α-tubulin.