van Deel Elza D, Najafi Aref, Fontoura Dulce, Valent Erik, Goebel Max, Kardux Kim, Falcão-Pires Inês, van der Velden Jolanda
Department of Physiology, Amsterdam Cardiovascular Sciences, VU University Medical Center, Amsterdam, the Netherlands.
Department of Surgery and Physiology, Faculty of Medicine, Universidade do Porto, Portugal.
J Physiol. 2017 Jul 15;595(14):4597-4610. doi: 10.1113/JP274460. Epub 2017 Jun 21.
This paper describes a novel model that allows exploration of matrix-induced cardiomyocyte adaptations independent of the passive effect of matrix rigidity on cardiomyocyte function. Detachment of adult cardiomyocytes from the matrix enables the study of matrix effects on cell shortening, Ca handling and myofilament function. Cell shortening and Ca handling are altered in cardiomyocytes cultured for 24 h on a stiff matrix. Matrix stiffness-impaired cardiomyocyte contractility is reversed upon normalization of extracellular stiffness. Matrix stiffness-induced reduction in unloaded shortening is more pronounced in cardiomyocytes isolated from obese ZSF1 rats with heart failure with preserved ejection fraction compared to lean ZSF1 rats.
Extracellular matrix (ECM) stiffening is a key element of cardiac disease. Increased rigidity of the ECM passively inhibits cardiac contraction, but if and how matrix stiffening also actively alters cardiomyocyte contractility is incompletely understood. In vitro models designed to study cardiomyocyte-matrix interaction lack the possibility to separate passive inhibition by a stiff matrix from active matrix-induced alterations of cardiomyocyte properties. Here we introduce a novel experimental model that allows exploration of cardiomyocyte functional alterations in response to matrix stiffening. Adult rat cardiomyocytes were cultured for 24 h on matrices of tuneable stiffness representing the healthy and the diseased heart and detached from their matrix before functional measurements. We demonstrate that matrix stiffening, independent of passive inhibition, reduces cell shortening and Ca handling but does not alter myofilament-generated force. Additionally, detachment of adult cultured cardiomyocytes allowed the transfer of cells from one matrix to another. This revealed that stiffness-induced cardiomyocyte changes are reversed when matrix stiffness is normalized. These matrix stiffness-induced changes in cardiomyocyte function could not be explained by adaptation in the microtubules. Additionally, cardiomyocytes isolated from stiff hearts of the obese ZSF1 rat model of heart failure with preserved ejection fraction show more pronounced reduction in unloaded shortening in response to matrix stiffening. Taken together, we introduce a method that allows evaluation of the influence of ECM properties on cardiomyocyte function separate from the passive inhibitory component of a stiff matrix. As such, it adds an important and physiologically relevant tool to investigate the functional consequences of cardiomyocyte-matrix interactions.
本文描述了一种新型模型，该模型能够独立于基质硬度对心肌细胞功能的被动影响，探索基质诱导的心肌细胞适应性变化。将成年心肌细胞与基质分离，能够研究基质对细胞缩短、钙处理和肌丝功能的影响。在刚性基质上培养24小时的心肌细胞，其细胞缩短和钙处理会发生改变。细胞外基质硬度恢复正常后，基质硬度受损的心肌细胞收缩力会逆转。与瘦型ZSF1大鼠相比，从射血分数保留的肥胖型ZSF1心力衰竭大鼠僵硬心脏中分离出的心肌细胞，基质硬度诱导的无负荷缩短减少更为明显。
细胞外基质（ECM）硬化是心脏疾病的关键因素。ECM硬度增加会被动抑制心脏收缩，但基质硬化是否以及如何主动改变心肌细胞收缩力尚不完全清楚。旨在研究心肌细胞与基质相互作用的体外模型，无法将刚性基质的被动抑制与基质主动诱导的心肌细胞特性改变区分开来。在此，我们引入一种新型实验模型，该模型能够探索心肌细胞对基质硬化的功能改变。成年大鼠心肌细胞在代表健康和患病心脏的可调硬度基质上培养24小时，并在功能测量前与基质分离。我们证明，基质硬化独立于被动抑制，会减少细胞缩短和钙处理，但不会改变肌丝产生的力量。此外，成年培养心肌细胞的分离使得细胞能够从一种基质转移到另一种基质。这表明，当基质硬度恢复正常时，硬度诱导的心肌细胞变化会逆转。这些基质硬度诱导的心肌细胞功能变化无法用微管适应来解释。此外，从射血分数保留的肥胖型ZSF1心力衰竭大鼠僵硬心脏中分离出的心肌细胞，对基质硬化的无负荷缩短减少更为明显。综上所述，我们引入了一种方法，该方法能够独立于刚性基质的被动抑制成分，评估ECM特性对心肌细胞功能的影响。因此，它为研究心肌细胞与基质相互作用带来了一种重要且与生理相关的工具。
