Reprogramming cardiomyocyte mechanosensing by crosstalk between integrins and hyaluronic acid receptors
ABSTRACT The elastic modulus of bioengineered materials has a strong influence on the phenotype of many cells including cardiomyocytes. On polyacrylamide (PAA) gels that are laminated with ligands for integrins, cardiac myocytes develop well organized sarcomeres only when cultured on substrates with elastic moduli in the range 10 kPa-30 kPa, near those of the healthy tissue. On stiffer substrates (>60 kPa) approximating the damaged heart, myocytes form stress fiber-like filament bundles but lack organized sarcomeres or an elongated shape. On soft (<1 kPa) PAA gels myocytes exhibit disorganized actin networks and sarcomeres. However, when the polyacrylamide matrix is replaced by hyaluronic acid (HA) as the gel network to which integrin ligands are attached, robust development of functional neonatal rat ventricular myocytes occurs on gels with elastic moduli of 200 Pa, a stiffness far below that of the neonatal heart and on which myocytes would be amorphous and dysfunctional when cultured on polyacrylamide-based gels. The HA matrix by itself is not adhesive for myocytes, and the myocyte phenotype depends on the type of integrin ligand that is incorporated within the HA gel, with fibronectin, gelatin, or fibrinogen being more effective than collagen I. These results show that HA alters the integrin-dependent stiffness response of cells in vitro and suggests that expression of HA within the extracellular matrix (ECM) in vivo might similarly alter the response of cells that bind the ECM through integrins. The integration of HA with integrin-specific ECM signaling proteins provides a rationale for engineering a new class of soft hybrid hydrogels that can be used in therapeutic strategies to reverse the remodeling of the injured myocardium.
- SourceAvailable from: Lauren Deems Black
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- "Interestingly , there is a matrix-dependent response of CMs to substrate stiffness. Hyaluronic acid (HA) has the potential to alter CMs' integrin-mediated response to stiffness, because when cultured on extremely soft substrates in the presence of HA, CMs maintain their ability to form organized sarcomeres . Further work is needed to understand the mechanism by which substrate composition mediates the cellular response to stiffness. "
ABSTRACT: The extracellular matrix is no longer considered a static support structure for cells, but a dynamic signaling network with the power to influence cell, tissue and whole organ physiology. In the myocardium, cardiac fibroblasts are the primary cell type responsible for the synthesis, deposition and degradation of matrix proteins and they therefore play a critical role in the development and maintenance of functional heart tissue. This review will summarize the extensive research conducted in vivo and in vitro demonstrating the influence of both physical and chemical stimuli on cardiac fibroblasts and how these interactions impact both cardiomyocytes and the extracellular matrix. This work is of considerable significance given that cardiovascular diseases are marked by extensive remodeling of the extracellular matrix, which ultimately impairs the functional capacity of the heart. We seek to summarize the unique role of cardiac fibroblasts in normal cardiac development and the most prevalent cardiac pathologies including congenital heart defects, hypertension, hypertrophy, and the remodeled heart following myocardial infarction. We will conclude by identifying existing holes in the research that, if answered, have the potential to dramatically improve current therapeutic strategies for the repair and regeneration of damaged myocardium via mechanotransductive signaling.Journal of Biomechanical Engineering 05/2013; DOI:10.1115/1.4024349 · 1.75 Impact Factor
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- "Rather than that, cells kept a round shaped morphology and did not interconnect to build up a contracting tissue construct. This was not surprising, since alginate and hyaluronic acid display low cell-adhesiveness  , which might also interfere with cell migration and tissue formation. Nevertheless , Live/Dead stainings demonstrated excellent cell viability within hydrogels, which highlights the value of this system for potential approaches like cell/hydrogel injection or tissue engineering of constructs with low cell density like cartilage and bone. "
ABSTRACT: Despite recent major advances including reprogramming and directed cardiac differentiation of human cells, therapeutic application of in vitro engineered myocardial tissue is still not feasible due to the inability to construct functional large vascularized contractile tissue patches based on clinically applicable and fully defined matrix components. Typical matrices with preformed porous 3D structure cannot be applied due to the obvious lack of migratory capacity of cardiomyocytes (CM). We have therefore developed a fully defined in situ hydrogelation system based on alginate (Alg) and hyaluronic acid (HyA), in which their aldehyde and hydrazide-derivatives enable covalent hydrazone cross-linking of polysaccharides in the presence of viable myocytes. By varying degrees of derivatization, concentrations and composition of blends in a modular system, mechanophysical properties of the resulting hydrogels are easily adjustable. The hydrogel allowed for the generation of contractile bioartificial cardiac tissue from CM-enriched neonatal rat heart cells, which resembles native myocardium. A combination of HyA and highly purified human collagen I led to significantly increased active contraction force compared to collagen, only. Therefore, our in situ cross-linking hydrogels represent a valuable toolbox for the fine-tuning of engineered cardiac tissue's mechanical properties and improved functionality, facilitating clinical translation toward therapeutic heart muscle reconstruction.Biomaterials 11/2012; 34(4). DOI:10.1016/j.biomaterials.2012.10.008 · 8.31 Impact Factor
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ABSTRACT: The current practice of cell therapy, in which multipotent or terminally differentiated cells are injected into tissues or intravenously, is inefficient. Few therapeutic cells are retained at the site of administration and engraftment is low. An injectable and biologically appropriate vehicle for delivery, retention, growth and differentiation of therapeutic cells is needed to improve the efficacy of cell therapy. We focus on a hyaluronan-based semi-synthetic extracellular matrix (sECM), HyStem®, which is a manufacturable, approvable and affordable clinical product. The composition of this sECM can be customized for use with mesenchymal stem cells as well as cells derived from embryonic or induced pluripotent sources. In addition, it can support therapeutic uses of progenitor and mature cell populations obtained from skin, fat, liver, heart, muscle, bone, cartilage, nerves and other tissues. This overview presents four pre-clinical uses of HyStem® for cell therapy to repair injured vocal folds, improve post-myocardial infarct heart function, regenerate damaged liver tissue and restore brain function following ischemic stroke. Finally, we address the real-world limitations - manufacture, regulation, market acceptance and financing - surrounding cell therapy and the development of clinical combination products.Acta biomaterialia 07/2012; 8(12). DOI:10.1016/j.actbio.2012.06.043 · 5.68 Impact Factor