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The use of poly(ethylene glycol) hydrogels to investigate the impact of ECM chemistry and mechanics on smooth muscle cells
Periodical: Biomaterials ISBN: 0142-9612 (Print)
Number: 28
Date: 2006/06/10
Language: eng
Pages: 4881-93
Authors:Peyton, S. R., Raub, C. B., Keschrumrus, V. P., Putnam, A. J.
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Abstract
Hydrogels based on poly(ethylene glycol) (PEG) are of increasing interest for regenerative medicine applications and are ideal materials to direct cell function due to the ability to confer key functionalities of native extracellular matrix (ECM) on PEG`s otherwise inert backbone. Given extensive recent evidence that ECM compliance influences a variety of cell functions, PEG-based hydrogels are also attractive due to the ease with which their mechanical properties can be controlled. In these studies, we exploited the chemical and mechanical tunability of PEG-based gels to study the impact of ECM chemistry and mechanics on smooth muscle cells (SMCs) in both 2-D and 3-D model systems. First, by controlling the extent of crosslinking and therefore the mechanical properties of PEG-based hydrogels (tensile moduli from 13.7 to 423.9kPa), we report here that the assembly of F-actin stress fibers and focal adhesions, indicative of the state of actin contractility, were influenced by the compliance of 2-D PEG gels functionalized with either short adhesive peptides or full-length ECM proteins. Varying ECM ligand density and identity independent of gel compliance affected the physical properties of the focal adhesions, and also influenced SMC spreading in 2-D. Furthermore, SMCs proliferated to a greater extent as gel stiffness was increased. In contrast, the degree of SMC differentiation, which was qualitatively assessed by the extent of smooth muscle alpha-actin bundling and the association of calponin and caldesmon with the alpha-actin fibrils, was found to decrease with substrate stiffness in 2-D cultures. In 3-D, despite the fact that their viability and degree of spreading were greatly reduced, SMCs did express some contractile markers indicative of their differentiated phenotype when cultured within PEG-RGDS constructs. Combined, these data suggest that the mechanical and chemical properties of PEG hydrogels can be tuned to influence SMC phenotype in both 2-D and 3-D.
Hydrogels based on poly(ethylene glycol) (PEG) are of increasing interest for regenerative medicine applications and are ideal materials to direct cell function due to the ability to confer key functionalities of native extracellular matrix (ECM) on PEG`s otherwise inert backbone. Given extensive recent evidence that ECM compliance influences a variety of cell functions, PEG-based hydrogels are also attractive due to the ease with which their mechanical properties can be controlled. In these studies, we exploited the chemical and mechanical tunability of PEG-based gels to study the impact of ECM chemistry and mechanics on smooth muscle cells (SMCs) in both 2-D and 3-D model systems. First, by controlling the extent of crosslinking and therefore the mechanical properties of PEG-based hydrogels (tensile moduli from 13.7 to 423.9kPa), we report here that the assembly of F-actin stress fibers and focal adhesions, indicative of the state of actin contractility, were influenced by the compliance of 2-D PEG gels functionalized with either short adhesive peptides or full-length ECM proteins. Varying ECM ligand density and identity independent of gel compliance affected the physical properties of the focal adhesions, and also influenced SMC spreading in 2-D. Furthermore, SMCs proliferated to a greater extent as gel stiffness was increased. In contrast, the degree of SMC differentiation, which was qualitatively assessed by the extent of smooth muscle alpha-actin bundling and the association of calponin and caldesmon with the alpha-actin fibrils, was found to decrease with substrate stiffness in 2-D cultures. In 3-D, despite the fact that their viability and degree of spreading were greatly reduced, SMCs did express some contractile markers indicative of their differentiated phenotype when cultured within PEG-RGDS constructs. Combined, these data suggest that the mechanical and chemical properties of PEG hydrogels can be tuned to influence SMC phenotype in both 2-D and 3-D.
Keywords
Actins/metabolism, Aorta/cytology, Cell Culture Techniques/*methods, Cell Proliferation/drug effects, Cell Survival/drug effects, Cells, Cultured, Cross-Linking Reagents/chemistry, Enzyme Activation/drug effects, Extracellular Matrix/*chemistry, Fibrinogen/chemistry/pharmacology, Focal Adhesions/drug effects, Humans, Hydrogel/*metabolism, Microscopy, Electron, Scanning, Muscle Contraction/drug effects, Muscle, Smooth, Vascular/cytology, Myocytes, Smooth Muscle/cytology/drug effects/*metabolism/physiology, Polyethylene Glycols/chemistry/pharmacology, rhoA GTP-Binding Protein/*physiology, Stress, Mechanical, Time Factors, Vinculin/metabolism
Actins/metabolism, Aorta/cytology, Cell Culture Techniques/*methods, Cell Proliferation/drug effects, Cell Survival/drug effects, Cells, Cultured, Cross-Linking Reagents/chemistry, Enzyme Activation/drug effects, Extracellular Matrix/*chemistry, Fibrinogen/chemistry/pharmacology, Focal Adhesions/drug effects, Humans, Hydrogel/*metabolism, Microscopy, Electron, Scanning, Muscle Contraction/drug effects, Muscle, Smooth, Vascular/cytology, Myocytes, Smooth Muscle/cytology/drug effects/*metabolism/physiology, Polyethylene Glycols/chemistry/pharmacology, rhoA GTP-Binding Protein/*physiology, Stress, Mechanical, Time Factors, Vinculin/metabolism
3DCellculture.com's MAMI
search attributes
CellLine: Primary-hAortaSMC
Morphology: Smooth Muscle
Origin: Aorta
Species: Human
Scaffold Form: gel/hydrogelMorphology: Smooth Muscle
Origin: Aorta
Species: Human
Scaffold Material: PEG/ poly(ethylene glycol)
Scaffold Origin: synthetic
Scaffold Permanance: Degradable