101
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Drifka CR, Loeffler AG, Mathewson K, Keikhosravi A, Eickhoff JC, Liu Y, Weber SM, Kao WJ, Eliceiri KW. Highly aligned stromal collagen is a negative prognostic factor following pancreatic ductal adenocarcinoma resection. Oncotarget 2016; 7:76197-76213. [PMID: 27776346 PMCID: PMC5342807 DOI: 10.18632/oncotarget.12772] [Citation(s) in RCA: 147] [Impact Index Per Article: 18.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 10/03/2016] [Indexed: 01/18/2023] Open
Abstract
Risk factors for pancreatic ductal adenocarcinoma (PDAC) progression after surgery are unclear, and additional prognostic factors are needed to inform treatment regimens and therapeutic targets. PDAC is characterized by advanced sclerosis of the extracellular matrix, and interactions between cancer cells, fibrillar collagen, and other stromal components play an integral role in progression. Changes in stromal collagen alignment have been shown to modulate cancer cell behavior and have important clinical value in other cancer types, but little is known about its role in PDAC and prognostic value. We hypothesized that the alignment of collagen is associated with PDAC patient survival. To address this, pathology-confirmed tissues from 114 PDAC patients that underwent curative-intent surgery were retrospectively imaged with Second Harmonic Generation (SHG) microscopy, quantified with fiber segmentation algorithms, and correlated to patient survival. The same tissue regions were analyzed for epithelial-to-mesenchymal (EMT), α-SMA, and syndecan-1 using complimentary immunohistostaining and visualization techniques. Significant inter-tumoral variation in collagen alignment was found, and notably high collagen alignment was observed in 12% of the patient cohort. Stratification of patients according to collagen alignment revealed that high alignment is an independent negative factor following PDAC resection (p = 0.0153, multivariate). We also found that epithelial expression of EMT and the stromal expression of α-SMA and syndecan-1 were positively correlated with collagen alignment. In summary, stromal collagen alignment may provide additional, clinically-relevant information about PDAC tumors and underscores the importance of stroma-cancer interactions.
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Affiliation(s)
- Cole R. Drifka
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
- Laboratory for Optical and Computational Instrumentation, University of Wisconsin, Madison, WI, USA
- Morgridge Institute for Research, Madison, WI, USA
| | - Agnes G. Loeffler
- Department of Surgical Pathology, University of Wisconsin, Madison, WI, USA
| | - Kara Mathewson
- Laboratory for Optical and Computational Instrumentation, University of Wisconsin, Madison, WI, USA
| | - Adib Keikhosravi
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
- Laboratory for Optical and Computational Instrumentation, University of Wisconsin, Madison, WI, USA
| | - Jens C. Eickhoff
- Department of Biostatistics and Medical Informatics, University of Wisconsin, Madison, WI, USA
| | - Yuming Liu
- Laboratory for Optical and Computational Instrumentation, University of Wisconsin, Madison, WI, USA
| | - Sharon M. Weber
- Department of Surgery, University of Wisconsin, Madison, WI, USA
- University of Wisconsin Carbone Cancer Center, Madison, WI, USA
| | - W. John Kao
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
- Department of Surgery, University of Wisconsin, Madison, WI, USA
- University of Wisconsin Carbone Cancer Center, Madison, WI, USA
| | - Kevin W. Eliceiri
- Department of Biomedical Engineering, University of Wisconsin, Madison, WI, USA
- Laboratory for Optical and Computational Instrumentation, University of Wisconsin, Madison, WI, USA
- Morgridge Institute for Research, Madison, WI, USA
- University of Wisconsin Carbone Cancer Center, Madison, WI, USA
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102
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Hogrebe NJ, Reinhardt JW, Gooch KJ. Biomaterial microarchitecture: a potent regulator of individual cell behavior and multicellular organization. J Biomed Mater Res A 2016; 105:640-661. [DOI: 10.1002/jbm.a.35914] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2016] [Revised: 08/17/2016] [Accepted: 09/02/2016] [Indexed: 11/12/2022]
Affiliation(s)
- Nathaniel J. Hogrebe
- Department of Biomedical EngineeringThe Ohio State University270 Bevis Hall 1080 Carmack RdColumbus Ohio43210
| | - James W. Reinhardt
- Department of Biomedical EngineeringThe Ohio State University270 Bevis Hall 1080 Carmack RdColumbus Ohio43210
| | - Keith J. Gooch
- Department of Biomedical EngineeringThe Ohio State University270 Bevis Hall 1080 Carmack RdColumbus Ohio43210
- The Ohio State University, Davis Heart Lung Research Institute473 W 12th AveColumbus Ohio43210
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103
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Liang L, Jones C, Chen S, Sun B, Jiao Y. Heterogeneous force network in 3D cellularized collagen networks. Phys Biol 2016; 13:066001. [PMID: 27779119 DOI: 10.1088/1478-3975/13/6/066001] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Collagen networks play an important role in coordinating and regulating collective cellular dynamics via a number of signaling pathways. Here, we investigate the transmission of forces generated by contractile cells in 3D collagen-I networks. Specifically, the graph (bond-node) representations of collagen networks with collagen concentrations of 1, 2 and 4 mg ml-1 are derived from confocal microscopy data and used to model the network microstructure. Cell contraction is modeled by applying correlated displacements at specific nodes of the network, representing the focal adhesion sites. A nonlinear elastic model is employed to characterize the mechanical behavior of individual fiber bundles including strain hardening during stretching and buckling under compression. A force-based relaxation method is employed to obtain equilibrium network configurations under cell contraction. We find that for all collagen concentrations, the majority of the forces are carried by a small number of heterogeneous force chains emitted from the contracting cells, which is qualitatively consistent with our experimental observations. The force chains consist of fiber segments that either possess a high degree of alignment before cell contraction or are aligned due to fiber reorientation induced by cell contraction. The decay of the forces along the force chains is significantly slower than the decay of radially averaged forces in the system, suggesting that the fibreous nature of biopolymer network structure can support long-range force transmission. The force chains emerge even at very small cell contractions, and the number of force chains increases with increasing cell contraction. At large cell contractions, the fibers close to the cell surface are in the nonlinear regime, and the nonlinear region is localized in a small neighborhood of the cell. In addition, the number of force chains increases with increasing collagen concentration, due to the larger number of focal adhesion sites in collagen networks with high concentrations.
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Affiliation(s)
- Long Liang
- Department of Physics, Arizona State University, Tempe, AZ, 85287, USA
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104
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Mak M, Spill F, Kamm RD, Zaman MH. Single-Cell Migration in Complex Microenvironments: Mechanics and Signaling Dynamics. J Biomech Eng 2016; 138:021004. [PMID: 26639083 DOI: 10.1115/1.4032188] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2015] [Indexed: 12/21/2022]
Abstract
Cells are highly dynamic and mechanical automata powered by molecular motors that respond to external cues. Intracellular signaling pathways, either chemical or mechanical, can be activated and spatially coordinated to induce polarized cell states and directional migration. Physiologically, cells navigate through complex microenvironments, typically in three-dimensional (3D) fibrillar networks. In diseases, such as metastatic cancer, they invade across physiological barriers and remodel their local environments through force, matrix degradation, synthesis, and reorganization. Important external factors such as dimensionality, confinement, topographical cues, stiffness, and flow impact the behavior of migrating cells and can each regulate motility. Here, we review recent progress in our understanding of single-cell migration in complex microenvironments.
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105
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106
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Wang K, Wu F, Seo BR, Fischbach C, Chen W, Hsu L, Gourdon D. Breast cancer cells alter the dynamics of stromal fibronectin-collagen interactions. Matrix Biol 2016; 60-61:86-95. [PMID: 27503584 DOI: 10.1016/j.matbio.2016.08.001] [Citation(s) in RCA: 67] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2016] [Revised: 07/29/2016] [Accepted: 08/02/2016] [Indexed: 12/18/2022]
Abstract
Breast cancer cells recruit surrounding stromal cells, such as cancer-associated fibroblasts (CAFs), to remodel their extracellular matrix (ECM) and promote invasive tumor growth. Two major ECM components, fibronectin (Fn) and collagen I (Col I), are known to interact with each other to regulate cellular behavior. In this study, we seek to understand how Fn and Col I interplay and promote a dysregulated signaling pathway to facilitate tumor progression. Specifically, we investigated the evolution of tumor-conditioned stromal ECM composition, structure, and relaxation. Furthermore, we assessed how evolving Fn-Col I interactions gradually affected pro-angiogenic signaling. Our data first indicate that CAFs initially assembled a strained, viscous, and unfolded Fn matrix. This early altered Fn matrix was later remodeled into a thick Col I-rich matrix that was characteristic of a dense tumor mass. Next, our results suggest that this ECM remodeling was primarily mediated by matrix metalloproteinases (MMPs). This MMP activity caused profound structural and mechanical changes in the developing ECM, which then modified vascular endothelial growth factor (VEGF) secretion by CAFs and matrix sequestration. Collectively, these findings enhance our understanding of the mechanisms by which Fn and Col I synergistically interplay in promoting a sustained altered signaling cascade to remodel the breast tumor stroma for invasive breast tumor growth.
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Affiliation(s)
- Karin Wang
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14583, USA; Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14583, USA
| | - Fei Wu
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14583, USA
| | - Bo Ri Seo
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14583, USA
| | - Claudia Fischbach
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY 14583, USA
| | - Weisi Chen
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14583, USA
| | - Lauren Hsu
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14583, USA
| | - Delphine Gourdon
- Department of Materials Science and Engineering, Cornell University, Ithaca, NY 14583, USA; Department of Physics, University of Ottawa, Ottawa, ON, K1N 6N5, Canada.
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107
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Welf ES, Driscoll MK, Dean KM, Schäfer C, Chu J, Davidson MW, Lin MZ, Danuser G, Fiolka R. Quantitative Multiscale Cell Imaging in Controlled 3D Microenvironments. Dev Cell 2016; 36:462-75. [PMID: 26906741 DOI: 10.1016/j.devcel.2016.01.022] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2015] [Revised: 11/11/2015] [Accepted: 01/26/2016] [Indexed: 12/30/2022]
Abstract
The microenvironment determines cell behavior, but the underlying molecular mechanisms are poorly understood because quantitative studies of cell signaling and behavior have been challenging due to insufficient spatial and/or temporal resolution and limitations on microenvironmental control. Here we introduce microenvironmental selective plane illumination microscopy (meSPIM) for imaging and quantification of intracellular signaling and submicrometer cellular structures as well as large-scale cell morphological and environmental features. We demonstrate the utility of this approach by showing that the mechanical properties of the microenvironment regulate the transition of melanoma cells from actin-driven protrusion to blebbing, and we present tools to quantify how cells manipulate individual collagen fibers. We leverage the nearly isotropic resolution of meSPIM to quantify the local concentration of actin and phosphatidylinositol 3-kinase signaling on the surfaces of cells deep within 3D collagen matrices and track the many small membrane protrusions that appear in these more physiologically relevant environments.
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Affiliation(s)
- Erik S Welf
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Meghan K Driscoll
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Kevin M Dean
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Claudia Schäfer
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Jun Chu
- Departments of Bioengineering and Pediatrics, Stanford University, Stanford, CA 94305, USA
| | - Michael W Davidson
- National High Magnetic Field Laboratory, Department of Biological Science, Florida State University, Tallahassee, FL 32310, USA
| | - Michael Z Lin
- Departments of Bioengineering and Pediatrics, Stanford University, Stanford, CA 94305, USA
| | - Gaudenz Danuser
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
| | - Reto Fiolka
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA.
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108
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Schnauß J, Händler T, Käs JA. Semiflexible Biopolymers in Bundled Arrangements. Polymers (Basel) 2016; 8:polym8080274. [PMID: 30974551 PMCID: PMC6432226 DOI: 10.3390/polym8080274] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2016] [Revised: 07/18/2016] [Accepted: 07/19/2016] [Indexed: 12/15/2022] Open
Abstract
Bundles and networks of semiflexible biopolymers are key elements in cells, lending them mechanical integrity while also enabling dynamic functions. Networks have been the subject of many studies, revealing a variety of fundamental characteristics often determined via bulk measurements. Although bundles are equally important in biological systems, they have garnered much less scientific attention since they have to be probed on the mesoscopic scale. Here, we review theoretical as well as experimental approaches, which mainly employ the naturally occurring biopolymer actin, to highlight the principles behind these structures on the single bundle level.
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Affiliation(s)
- Jörg Schnauß
- Institute for Experimental Physics I, Universität Leipzig, Linnéstraße 5, Leipzig 04103, Germany.
- Fraunhofer Institute for Cell Therapy and Immunology, Perlickstraße 1, Leipzig 04103, Germany.
| | - Tina Händler
- Institute for Experimental Physics I, Universität Leipzig, Linnéstraße 5, Leipzig 04103, Germany.
- Fraunhofer Institute for Cell Therapy and Immunology, Perlickstraße 1, Leipzig 04103, Germany.
| | - Josef A Käs
- Institute for Experimental Physics I, Universität Leipzig, Linnéstraße 5, Leipzig 04103, Germany.
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109
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Bersini S, Yazdi IK, Talò G, Shin SR, Moretti M, Khademhosseini A. Cell-microenvironment interactions and architectures in microvascular systems. Biotechnol Adv 2016; 34:1113-1130. [PMID: 27417066 DOI: 10.1016/j.biotechadv.2016.07.002] [Citation(s) in RCA: 42] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2015] [Revised: 07/02/2016] [Accepted: 07/09/2016] [Indexed: 02/06/2023]
Abstract
In the past decade, significant advances have been made in the design and optimization of novel biomaterials and microfabrication techniques to generate vascularized tissues. Novel microfluidic systems have facilitated the development and optimization of in vitro models for exploring the complex pathophysiological phenomena that occur inside a microvascular environment. To date, most of these models have focused on engineering of increasingly complex systems, rather than analyzing the molecular and cellular mechanisms that drive microvascular network morphogenesis and remodeling. In fact, mutual interactions among endothelial cells (ECs), supporting mural cells and organ-specific cells, as well as between ECs and the extracellular matrix, are key driving forces for vascularization. This review focuses on the integration of materials science, microengineering and vascular biology for the development of in vitro microvascular systems. Various approaches currently being applied to study cell-cell/cell-matrix interactions, as well as biochemical/biophysical cues promoting vascularization and their impact on microvascular network formation, will be identified and discussed. Finally, this review will explore in vitro applications of microvascular systems, in vivo integration of transplanted vascularized tissues, and the important challenges for vascularization and controlling the microcirculatory system within the engineered tissues, especially for microfabrication approaches. It is likely that existing models and more complex models will further our understanding of the key elements of vascular network growth, stabilization and remodeling to translate basic research principles into functional, vascularized tissue constructs for regenerative medicine applications, drug screening and disease models.
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Affiliation(s)
- Simone Bersini
- Cell and Tissue Engineering Lab, IRCCS Istituto Ortopedico Galeazzi, Milano, Italy
| | - Iman K Yazdi
- Biomaterials Innovation Research Center, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02139, USA
| | - Giuseppe Talò
- Cell and Tissue Engineering Lab, IRCCS Istituto Ortopedico Galeazzi, Milano, Italy
| | - Su Ryon Shin
- Biomaterials Innovation Research Center, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02139, USA
| | - Matteo Moretti
- Cell and Tissue Engineering Lab, IRCCS Istituto Ortopedico Galeazzi, Milano, Italy; Regenerative Medicine Technologies Lab, Ente Ospedaliero Cantonale, Lugano, Switzerland; Swiss Institute for Regenerative Medicine, Lugano, Switzerland; Cardiocentro Ticino, Lugano, Switzerland.
| | - Ali Khademhosseini
- Biomaterials Innovation Research Center, Brigham and Women's Hospital, Harvard Medical School, Cambridge, MA, USA; Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, Cambridge, MA 02139, USA; Department of Physics, King Abdulaziz University, Jeddah 21569, Saudi Arabia; College of Animal Bioscience and Technology, Department of Bioindustrial Technologies, Konkuk University, Hwayang-dong, Kwangjin-gu, Seoul 143-701, Republic of Korea.
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110
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Thayer PS, Verbridge SS, Dahlgren LA, Kakar S, Guelcher SA, Goldstein AS. Fiber/collagen composites for ligament tissue engineering: influence of elastic moduli of sparse aligned fibers on mesenchymal stem cells. J Biomed Mater Res A 2016; 104:1894-901. [DOI: 10.1002/jbm.a.35716] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2016] [Revised: 03/07/2016] [Accepted: 03/14/2016] [Indexed: 01/13/2023]
Affiliation(s)
- Patrick S. Thayer
- Virginia Tech/Wake Forest School of Biomedical Engineering and Sciences; Virginia Tech; Blacksburg Virginia 24061
| | - Scott S. Verbridge
- Virginia Tech/Wake Forest School of Biomedical Engineering and Sciences; Virginia Tech; Blacksburg Virginia 24061
| | - Linda A. Dahlgren
- Department of Large Animal Clinical Sciences; Virginia-Maryland College of Veterinary Medicine, Virginia Tech; Blacksburg Virginia 24061
| | - Sanjeev Kakar
- Orthopedic Surgery; Mayo Clinic; Rochester Minnesota 55905
| | - Scott A. Guelcher
- Department of Chemical and Biomolecular Engineering; Vanderbilt University; Nashville Tennessee 37212
| | - Aaron S. Goldstein
- Virginia Tech/Wake Forest School of Biomedical Engineering and Sciences; Virginia Tech; Blacksburg Virginia 24061
- Department of Chemical Engineering; Virginia Tech; Blacksburg Virginia 24061
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111
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Lorden ER, Miller KJ, Ibrahim MM, Bashirov L, Hammett E, Chakraborty S, Quiles-Torres C, Selim MA, Leong KW, Levinson H. Biostable electrospun microfibrous scaffolds mitigate hypertrophic scar contraction in an immune-competent murine model. Acta Biomater 2016; 32:100-109. [PMID: 26708709 DOI: 10.1016/j.actbio.2015.12.025] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2015] [Revised: 11/26/2015] [Accepted: 12/15/2015] [Indexed: 12/11/2022]
Abstract
Burn injuries in the United States account for over one million hospital admissions per year, with treatment estimated at four billion dollars. Of severe burn patients, 30-90% will develop hypertrophic scars (HSc). In this study, we evaluate the impact of an elastomeric, randomly-oriented biostable polyurethane (PU) scaffold on HSc-related outcomes. In vitro, fibroblast-seeded PU scaffolds contracted significantly less and demonstrated fewer αSMA(+) myofibroblasts compared to fibroblast-seeded collagen lattices. In a murine HSc model, collagen coated PU (ccPU) scaffolds significantly reduced HSc contraction as compared to untreated control wounds and wounds treated with the clinical standard of care. Our data suggest that electrospun ccPU scaffolds meet the requirements to reduce HSc contraction including reduction of in vitro HSc related outcomes, diminished scar stiffness, and reduced scar contraction. While clinical dogma suggests treating severe burn patients with rapidly biodegrading skin equivalents, our data suggest that a more long-term scaffold may possess merit in reducing HSc. STATEMENT OF SIGNIFICANCE In severe burns treated with skin grafting, between 30% and 90% of patients develop hypertrophic scars (HSc). There are no therapies to prevent HSc, and treatments are marginally effective. This work is the first example we are aware of which studies the impact of a permanent electrospun elastomer on HSc contraction in a murine model that mimics the human condition. Collagen coated polyurethane scaffolds decrease αSMA+ myofibroblast formation in vitro, prevent stiffening of scar tissue, and mitigate HSc contraction. Unlike current standards of care, electrospun, polyurethane scaffolds do not lose architecture over time. We propose that the future bioengineering strategy of mitigating HSc contraction should consider a long-term elastomeric matrix which persists within the wound bed throughout the remodeling phase of repair.
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112
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Mullen CA, Vaughan TJ, Billiar KL, McNamara LM. The effect of substrate stiffness, thickness, and cross-linking density on osteogenic cell behavior. Biophys J 2016; 108:1604-1612. [PMID: 25863052 DOI: 10.1016/j.bpj.2015.02.022] [Citation(s) in RCA: 70] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2014] [Revised: 02/15/2015] [Accepted: 02/23/2015] [Indexed: 11/16/2022] Open
Abstract
Osteogenic cells respond to mechanical changes in their environment by altering their spread area, morphology, and gene expression profile. In particular, the bulk modulus of the substrate, as well as its microstructure and thickness, can substantially alter the local stiffness experienced by the cell. Although bone tissue regeneration strategies involve culture of bone cells on various biomaterial scaffolds, which are often cross-linked to enhance their physical integrity, it is difficult to ascertain and compare the local stiffness experienced by cells cultured on different biomaterials. In this study, we seek to characterize the local stiffness at the cellular level for MC3T3-E1 cells plated on biomaterial substrates of varying modulus, thickness, and cross-linking concentration. Cells were cultured on flat and wedge-shaped gels made from polyacrylamide or cross-linked collagen. The cross-linking density of the collagen gels was varied to investigate the effect of fiber cross-linking in conjunction with substrate thickness. Cell spread area was used as a measure of osteogenic differentiation. Finite element simulations were used to examine the effects of fiber cross-linking and substrate thickness on the resistance of the gel to cellular forces, corresponding to the equivalent shear stiffness for the gel structure in the region directly surrounding the cell. The results of this study show that MC3T3 cells cultured on a soft fibrous substrate attain the same spread cell area as those cultured on a much higher modulus, but nonfibrous substrate. Finite element simulations predict that a dramatic increase in the equivalent shear stiffness of fibrous collagen gels occurs as cross-linking density is increased, with equivalent stiffness also increasing as gel thickness is decreased. These results provide an insight into the response of osteogenic cells to individual substrate parameters and have the potential to inform future bone tissue regeneration strategies that can optimize the equivalent stiffness experienced by a cell.
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Affiliation(s)
- Conleth A Mullen
- Centre for Biomechanics Research (BMEC), Department of Biomedical Engineering, NUI Galway, Galway, Ireland; National Centre for Biomedical Engineering Science (NCBES), NUI Galway, Galway, Ireland
| | - Ted J Vaughan
- Centre for Biomechanics Research (BMEC), Department of Biomedical Engineering, NUI Galway, Galway, Ireland
| | - Kristen L Billiar
- Department Biomedical Engineering, Worcester Polytechnic Institute, Worcester, Massachusetts
| | - Laoise M McNamara
- Centre for Biomechanics Research (BMEC), Department of Biomedical Engineering, NUI Galway, Galway, Ireland; National Centre for Biomedical Engineering Science (NCBES), NUI Galway, Galway, Ireland.
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113
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Kurniawan NA, Chaudhuri PK, Lim CT. Mechanobiology of cell migration in the context of dynamic two-way cell-matrix interactions. J Biomech 2015; 49:1355-1368. [PMID: 26747513 DOI: 10.1016/j.jbiomech.2015.12.023] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Revised: 11/30/2015] [Accepted: 12/14/2015] [Indexed: 12/31/2022]
Abstract
Migration of cells is integral in various physiological processes in all facets of life. These range from embryonic development, morphogenesis, and wound healing, to disease pathology such as cancer metastasis. While cell migratory behavior has been traditionally studied using simple assays on culture dishes, in recent years it has been increasingly realized that the physical, mechanical, and chemical aspects of the matrix are key determinants of the migration mechanism. In this paper, we will describe the mechanobiological changes that accompany the dynamic cell-matrix interactions during cell migration. Furthermore, we will review what is to date known about how these changes feed back to the dynamics and biomechanical properties of the cell and the matrix. Elucidating the role of these intimate cell-matrix interactions will provide not only a better multi-scale understanding of cell motility in its physiological context, but also a more holistic perspective for designing approaches to regulate cell behavior.
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Affiliation(s)
- Nicholas A Kurniawan
- Department of Biomedical Engineering, Eindhoven University of Technology, P.O. Box 513, 5600MB Eindhoven, The Netherlands; Department of Systems Biophysics, FOM Institute AMOLF, Amsterdam, The Netherlands.
| | | | - Chwee Teck Lim
- Mechanobiology Institute, National University of Singapore, Singapore; Department of Biomedical Engineering, National University of Singapore, Singapore.
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114
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Baker BM, Trappmann B, Wang WY, Sakar MS, Kim IL, Shenoy VB, Burdick JA, Chen CS. Cell-mediated fibre recruitment drives extracellular matrix mechanosensing in engineered fibrillar microenvironments. NATURE MATERIALS 2015; 14:1262-8. [PMID: 26461445 PMCID: PMC4654682 DOI: 10.1038/nmat4444] [Citation(s) in RCA: 366] [Impact Index Per Article: 40.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/10/2014] [Accepted: 08/28/2015] [Indexed: 05/17/2023]
Abstract
To investigate how cells sense stiffness in settings structurally similar to native extracellular matrices, we designed a synthetic fibrous material with tunable mechanics and user-defined architecture. In contrast to flat hydrogel surfaces, these fibrous materials recapitulated cell-matrix interactions observed with collagen matrices including stellate cell morphologies, cell-mediated realignment of fibres, and bulk contraction of the material. Increasing the stiffness of flat hydrogel surfaces induced mesenchymal stem cell spreading and proliferation; however, increasing fibre stiffness instead suppressed spreading and proliferation for certain network architectures. Lower fibre stiffness permitted active cellular forces to recruit nearby fibres, dynamically increasing ligand density at the cell surface and promoting the formation of focal adhesions and related signalling. These studies demonstrate a departure from the well-described relationship between material stiffness and spreading established with hydrogel surfaces, and introduce fibre recruitment as a previously undescribed mechanism by which cells probe and respond to mechanics in fibrillar matrices.
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Affiliation(s)
- Brendon M. Baker
- Tissue Microfabrication Lab, Department of Biomedical Engineering, Boston University, Boston, MA 02215
- Wyss Institute for Biologically Inspired Engineering, Center for Life Science Boston Building, 5th Floor, 3 Blackfan Circle, Boston, MA 02115
- Corresponding Authors: Christopher S. Chen, M.D., Ph.D., Department of Biomedical Engineering, Boston University, SLB201, 36 Cummington Mall, Boston, MA 02215, Phone: (617) 353-1699, Fax: (617) 353-6766, , Brendon M. Baker, Ph.D., Department of Biomedical Engineering, Boston University, SLB304, 36 Cummington Mall, Boston, MA 02215, Phone: (617) 353-1699, Fax: (617) 353-6766,
| | - Britta Trappmann
- Tissue Microfabrication Lab, Department of Biomedical Engineering, Boston University, Boston, MA 02215
- Wyss Institute for Biologically Inspired Engineering, Center for Life Science Boston Building, 5th Floor, 3 Blackfan Circle, Boston, MA 02115
| | - William Y. Wang
- Tissue Microfabrication Lab, Department of Biomedical Engineering, Boston University, Boston, MA 02215
| | - Mahmut S. Sakar
- Institute of Robotics and Intelligent Systems, Eidgenössische Technische Hochschule Zürich, CH-8092 Zürich, Switzerland
| | - Iris L. Kim
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104
| | - Vivek B. Shenoy
- Department of Mechanical Engineering, University of Pennsylvania, Philadelphia, PA 19104
| | - Jason A. Burdick
- Department of Bioengineering, University of Pennsylvania, Philadelphia, PA 19104
| | - Christopher S. Chen
- Tissue Microfabrication Lab, Department of Biomedical Engineering, Boston University, Boston, MA 02215
- Wyss Institute for Biologically Inspired Engineering, Center for Life Science Boston Building, 5th Floor, 3 Blackfan Circle, Boston, MA 02115
- Corresponding Authors: Christopher S. Chen, M.D., Ph.D., Department of Biomedical Engineering, Boston University, SLB201, 36 Cummington Mall, Boston, MA 02215, Phone: (617) 353-1699, Fax: (617) 353-6766, , Brendon M. Baker, Ph.D., Department of Biomedical Engineering, Boston University, SLB304, 36 Cummington Mall, Boston, MA 02215, Phone: (617) 353-1699, Fax: (617) 353-6766,
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115
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Integrative Utilization of Microenvironments, Biomaterials and Computational Techniques for Advanced Tissue Engineering. J Biotechnol 2015; 212:71-89. [DOI: 10.1016/j.jbiotec.2015.08.005] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2015] [Revised: 08/02/2015] [Accepted: 08/11/2015] [Indexed: 01/13/2023]
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116
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Xu X, Safran SA. Nonlinearities of biopolymer gels increase the range of force transmission. PHYSICAL REVIEW. E, STATISTICAL, NONLINEAR, AND SOFT MATTER PHYSICS 2015; 92:032728. [PMID: 26465519 DOI: 10.1103/physreve.92.032728] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/21/2015] [Indexed: 06/05/2023]
Abstract
We present a model of biopolymer gels that includes two types of elastic nonlinearities, stiffening under extension and softening (due to buckling) under compression, to predict the elastic anisotropy induced by both external as well as internal (e.g., due to cell contractility) stresses in biopolymer gels. We show how the stretch-induced anisotropy and the strain-stiffening nonlinearity increase both the amplitude and power-law range of transmission of internal, contractile, cellular forces, and relate this to recent experiments.
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Affiliation(s)
- Xinpeng Xu
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
| | - Samuel A Safran
- Department of Materials and Interfaces, Weizmann Institute of Science, Rehovot 76100, Israel
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117
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Abhilash AS, Baker BM, Trappmann B, Chen CS, Shenoy VB. Remodeling of fibrous extracellular matrices by contractile cells: predictions from discrete fiber network simulations. Biophys J 2015; 107:1829-1840. [PMID: 25418164 DOI: 10.1016/j.bpj.2014.08.029] [Citation(s) in RCA: 128] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 08/07/2014] [Accepted: 08/27/2014] [Indexed: 10/24/2022] Open
Abstract
Contractile forces exerted on the surrounding extracellular matrix (ECM) lead to the alignment and stretching of constituent fibers within the vicinity of cells. As a consequence, the matrix reorganizes to form thick bundles of aligned fibers that enable force transmission over distances larger than the size of the cells. Contractile force-mediated remodeling of ECM fibers has bearing on a number of physiologic and pathophysiologic phenomena. In this work, we present a computational model to capture cell-mediated remodeling within fibrous matrices using finite element-based discrete fiber network simulations. The model is shown to accurately capture collagen alignment, heterogeneous deformations, and long-range force transmission observed experimentally. The zone of mechanical influence surrounding a single contractile cell and the interaction between two cells are predicted from the strain-induced alignment of fibers. Through parametric studies, the effect of cell contractility and cell shape anisotropy on matrix remodeling and force transmission are quantified and summarized in a phase diagram. For highly contractile and elongated cells, we find a sensing distance that is ten times the cell size, in agreement with experimental observations.
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Affiliation(s)
- A S Abhilash
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Brendon M Baker
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts
| | - Britta Trappmann
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts
| | - Christopher S Chen
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts
| | - Vivek B Shenoy
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania.
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118
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Mak M, Kim T, Zaman MH, Kamm RD. Multiscale mechanobiology: computational models for integrating molecules to multicellular systems. Integr Biol (Camb) 2015; 7:1093-108. [PMID: 26019013 DOI: 10.1039/c5ib00043b] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Mechanical signals exist throughout the biological landscape. Across all scales, these signals, in the form of force, stiffness, and deformations, are generated and processed, resulting in an active mechanobiological circuit that controls many fundamental aspects of life, from protein unfolding and cytoskeletal remodeling to collective cell motions. The multiple scales and complex feedback involved present a challenge for fully understanding the nature of this circuit, particularly in development and disease in which it has been implicated. Computational models that accurately predict and are based on experimental data enable a means to integrate basic principles and explore fine details of mechanosensing and mechanotransduction in and across all levels of biological systems. Here we review recent advances in these models along with supporting and emerging experimental findings.
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Affiliation(s)
- Michael Mak
- Department of Mechanical Engineering, Massachusetts Institute of Technology, Cambridge, MA, USA.
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119
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Jansen KA, Donato DM, Balcioglu HE, Schmidt T, Danen EHJ, Koenderink GH. A guide to mechanobiology: Where biology and physics meet. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:3043-52. [PMID: 25997671 DOI: 10.1016/j.bbamcr.2015.05.007] [Citation(s) in RCA: 176] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/29/2015] [Revised: 04/28/2015] [Accepted: 05/02/2015] [Indexed: 02/08/2023]
Abstract
Cells actively sense and process mechanical information that is provided by the extracellular environment to make decisions about growth, motility and differentiation. It is important to understand the underlying mechanisms given that deregulation of the mechanical properties of the extracellular matrix (ECM) is implicated in various diseases, such as cancer and fibrosis. Moreover, matrix mechanics can be exploited to program stem cell differentiation for organ-on-chip and regenerative medicine applications. Mechanobiology is an emerging multidisciplinary field that encompasses cell and developmental biology, bioengineering and biophysics. Here we provide an introductory overview of the key players important to cellular mechanobiology, taking a biophysical perspective and focusing on a comparison between flat versus three dimensional substrates. This article is part of a Special Issue entitled: Mechanobiology.
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Affiliation(s)
- Karin A Jansen
- Systems Biophysics Department, FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
| | - Dominique M Donato
- Physics of Life Processes, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
| | - Hayri E Balcioglu
- Faculty of Science, Leiden Academic Center for Drug Research, Toxicology, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Thomas Schmidt
- Physics of Life Processes, Huygens-Kamerlingh Onnes Laboratory, Leiden University, Niels Bohrweg 2, 2333 CA Leiden, The Netherlands
| | - Erik H J Danen
- Faculty of Science, Leiden Academic Center for Drug Research, Toxicology, Leiden University, Einsteinweg 55, 2333 CC Leiden, The Netherlands
| | - Gijsje H Koenderink
- Systems Biophysics Department, FOM Institute AMOLF, Science Park 104, 1098 XG Amsterdam, The Netherlands
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120
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Ma B, Smith BJ, Bates JHT. Resistance to alveolar shape change limits range of force propagation in lung parenchyma. Respir Physiol Neurobiol 2015; 211:22-8. [PMID: 25812796 DOI: 10.1016/j.resp.2015.03.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Revised: 02/24/2015] [Accepted: 03/17/2015] [Indexed: 11/18/2022]
Abstract
We have recently shown that if the lung parenchyma is modeled in 2 dimensions as a network of springs arranged in a pattern of repeating hexagonal cells, the distortional forces around a contracting airway propagate much further from the airway wall than classic continuum theory predicts. In the present study we tested the hypothesis that this occurs because of the negligible shear modulus of a hexagonal spring network. We simulated the narrowing of an airway embedded in a hexagonal network of elastic alveolar walls when the hexagonal cells of the network offered some resistance to a change in shape. We found that as the forces resisting shape change approach about 10% of the forces resisting length change of an individual spring the range of distortional force propagation in the spring network fell of rapidly as in an elastic continuum. We repeated these investigations in a 3-dimensional spring network composed of space-filling polyhedral cells and found similar results. This suggests that force propagation away from a point of local parenchymal distortion also falls off rapidly in real lung tissue.
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Affiliation(s)
- Baoshun Ma
- University of Vermont College of Medicine, Burlington, VT 05405, United States
| | - Bradford J Smith
- University of Vermont College of Medicine, Burlington, VT 05405, United States
| | - Jason H T Bates
- University of Vermont College of Medicine, Burlington, VT 05405, United States.
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121
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Utzinger U, Baggett B, Weiss JA, Hoying JB, Edgar LT. Large-scale time series microscopy of neovessel growth during angiogenesis. Angiogenesis 2015; 18:219-32. [PMID: 25795217 DOI: 10.1007/s10456-015-9461-x] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2014] [Accepted: 02/23/2015] [Indexed: 01/19/2023]
Abstract
During angiogenesis, growing neovessels must effectively navigate through the tissue space as they elongate and subsequently integrate into a microvascular network. While time series microscopy has provided insight into the cell activities within single growing neovessel sprouts, less is known concerning neovascular dynamics within a large angiogenic tissue bed. Here, we developed a time-lapse imaging technique that allowed visualization and quantification of sprouting neovessels as they form and grow away from adult parent microvessels in three dimensions over cubic millimeters of matrix volume during the course of up to 5 days on the microscope. Using a new image acquisition procedure and novel morphometric analysis tools, we quantified the elongation dynamics of growing neovessels and found an episodic growth pattern accompanied by fluctuations in neovessel diameter. Average elongation rate was 5 μm/h for individual vessels, but we also observed considerable dynamic variability in growth character including retraction and complete regression of entire neovessels. We observed neovessel-to-neovessel directed growth over tens to hundreds of microns preceding tip-to-tip inosculation. As we have previously described via static 3D imaging at discrete time points, we identified different collagen fibril structures associated with the growing neovessel tip and stalk, and observed the coordinated alignment of growing neovessels in a deforming matrix. Overall analysis of the entire image volumes demonstrated that although individual neovessels exhibited episodic growth and regression, there was a monotonic increase in parameters associated with the entire vascular bed such as total network length and number of branch points. This new time-lapse imaging approach corroborated morphometric changes in individual neovessels described by us and others, as well as captured dynamic neovessel behaviors unique to days-long angiogenesis within the forming neovascular network.
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Affiliation(s)
- Urs Utzinger
- Department of Biomedical Engineering, University of Arizona, Tucson, AZ, USA,
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122
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Mohammadi H, Arora PD, Simmons CA, Janmey PA, McCulloch CA. Inelastic behaviour of collagen networks in cell-matrix interactions and mechanosensation. J R Soc Interface 2015; 12:20141074. [PMID: 25392399 PMCID: PMC4277099 DOI: 10.1098/rsif.2014.1074] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2014] [Accepted: 10/17/2014] [Indexed: 12/15/2022] Open
Abstract
The mechanical properties of extracellular matrix proteins strongly influence cell-induced tension in the matrix, which in turn influences cell function. Despite progress on the impact of elastic behaviour of matrix proteins on cell-matrix interactions, little is known about the influence of inelastic behaviour, especially at the large and slow deformations that characterize cell-induced matrix remodelling. We found that collagen matrices exhibit deformation rate-dependent behaviour, which leads to a transition from pronounced elastic behaviour at fast deformations to substantially inelastic behaviour at slow deformations (1 μm min(-1), similar to cell-mediated deformation). With slow deformations, the inelastic behaviour of floating gels was sensitive to collagen concentration, whereas attached gels exhibited similar inelastic behaviour independent of collagen concentration. The presence of an underlying rigid support had a similar effect on cell-matrix interactions: cell-induced deformation and remodelling were similar on 1 or 3 mg ml(-1) attached collagen gels while deformations were two- to fourfold smaller in floating gels of high compared with low collagen concentration. In cross-linked collagen matrices, which did not exhibit inelastic behaviour, cells did not respond to the presence of the underlying rigid foundation. These data indicate that at the slow rates of collagen compaction generated by fibroblasts, the inelastic responses of collagen gels, which are influenced by collagen concentration and the presence of an underlying rigid foundation, are important determinants of cell-matrix interactions and mechanosensation.
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Affiliation(s)
- Hamid Mohammadi
- Matrix Dynamics Group, University of Toronto, Toronto, Ontario, Canada
| | - Pamma D Arora
- Matrix Dynamics Group, University of Toronto, Toronto, Ontario, Canada
| | - Craig A Simmons
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, Ontario, Canada
| | - Paul A Janmey
- Institute for Medicine and Engineering, University of Pennsylvania, Philadelphia, PA, USA
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123
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Wang H, Abhilash AS, Chen CS, Wells RG, Shenoy VB. Long-range force transmission in fibrous matrices enabled by tension-driven alignment of fibers. Biophys J 2014; 107:2592-603. [PMID: 25468338 DOI: 10.1016/j.bpj.2014.09.044] [Citation(s) in RCA: 199] [Impact Index Per Article: 19.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2014] [Revised: 08/21/2014] [Accepted: 09/18/2014] [Indexed: 11/26/2022] Open
Abstract
Cells can sense and respond to mechanical signals over relatively long distances across fibrous extracellular matrices. Recently proposed models suggest that long-range force transmission can be attributed to the nonlinear elasticity or fibrous nature of collagen matrices, yet the mechanism whereby fibers align remains unknown. Moreover, cell shape and anisotropy of cellular contraction are not considered in existing models, although recent experiments have shown that they play crucial roles. Here, we explore all of the key factors that influence long-range force transmission in cell-populated collagen matrices: alignment of collagen fibers, responses to applied force, strain stiffening properties of the aligned fibers, aspect ratios of the cells, and the polarization of cellular contraction. A constitutive law accounting for mechanically driven collagen fiber reorientation is proposed. We systematically investigate the range of collagen-fiber alignment using both finite-element simulations and analytical calculations. Our results show that tension-driven collagen-fiber alignment plays a crucial role in force transmission. Small critical stretch for fiber alignment, large fiber stiffness and fiber strain-hardening behavior enable long-range interaction. Furthermore, the range of collagen-fiber alignment for elliptical cells with polarized contraction is much larger than that for spherical cells with diagonal contraction. A phase diagram showing the range of force transmission as a function of cell shape and polarization and matrix properties is presented. Our results are in good agreement with recent experiments, and highlight the factors that influence long-range force transmission, in particular tension-driven alignment of fibers. Our work has important relevance to biological processes including development, cancer metastasis, and wound healing, suggesting conditions whereby cells communicate over long distances.
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Affiliation(s)
- Hailong Wang
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - A S Abhilash
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Christopher S Chen
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts
| | - Rebecca G Wells
- Departments of Medicine (GI) and Pathology and Laboratory Medicine, University of Pennsylvania, Philadelphia, Pennsylvania
| | - Vivek B Shenoy
- Department of Materials Science and Engineering, University of Pennsylvania, Philadelphia, Pennsylvania.
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124
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Jones CAR, Liang L, Lin D, Jiao Y, Sun B. The spatial-temporal characteristics of type I collagen-based extracellular matrix. SOFT MATTER 2014; 10:8855-8863. [PMID: 25287650 DOI: 10.1039/c4sm01772b] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
Type I collagen abounds in mammalian extracellular matrix (ECM) and is crucial to many biophysical processes. While previous studies have mostly focused on bulk averaged properties, here we provide a comprehensive and quantitative spatial-temporal characterization of the microstructure of type I collagen-based ECM as the gelation temperature varies. The structural characteristics including the density and nematic correlation functions are obtained by analyzing confocal images of collagen gels prepared at a wide range of gelation temperatures (from 16 °C to 36 °C). As temperature increases, the gel microstructure varies from a "bundled" network with strong orientational correlation between the fibers to an isotropic homogeneous network with no significant orientational correlation, as manifested by the decaying of length scales in the correlation functions. We develop a kinetic Monte-Carlo collagen growth model to better understand how ECM microstructure depends on various environmental or kinetic factors. We show that the nucleation rate, growth rate, and an effective hydrodynamic alignment of collagen fibers fully determines the spatiotemporal fluctuations of the density and orientational order of collagen gel microstructure. Also the temperature dependence of the growth rate and nucleation rate follow the prediction of classical nucleation theory.
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125
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Micro-composite substrates for the study of cell-matrix mechanical interactions. J Mech Behav Biomed Mater 2014; 38:232-41. [DOI: 10.1016/j.jmbbm.2014.01.008] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Revised: 12/03/2013] [Accepted: 01/14/2014] [Indexed: 01/13/2023]
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126
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Jansen KA, Bacabac RG, Piechocka IK, Koenderink GH. Cells actively stiffen fibrin networks by generating contractile stress. Biophys J 2014; 105:2240-51. [PMID: 24268136 DOI: 10.1016/j.bpj.2013.10.008] [Citation(s) in RCA: 104] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 09/03/2013] [Accepted: 10/07/2013] [Indexed: 12/13/2022] Open
Abstract
During wound healing and angiogenesis, fibrin serves as a provisional extracellular matrix. We use a model system of fibroblasts embedded in fibrin gels to study how cell-mediated contraction may influence the macroscopic mechanical properties of their extracellular matrix during such processes. We demonstrate by macroscopic shear rheology that the cells increase the elastic modulus of the fibrin gels. Microscopy observations show that this stiffening sets in when the cells spread and apply traction forces on the fibrin fibers. We further show that the stiffening response mimics the effect of an external stress applied by mechanical shear. We propose that stiffening is a consequence of active myosin-driven cell contraction, which provokes a nonlinear elastic response of the fibrin matrix. Cell-induced stiffening is limited to a factor 3 even though fibrin gels can in principle stiffen much more before breaking. We discuss this observation in light of recent models of fibrin gel elasticity, and conclude that the fibroblasts pull out floppy modes, such as thermal bending undulations, from the fibrin network, but do not axially stretch the fibers. Our findings are relevant for understanding the role of matrix contraction by cells during wound healing and cancer development, and may provide design parameters for materials to guide morphogenesis in tissue engineering.
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Affiliation(s)
- Karin A Jansen
- Biological Soft Matter Group, FOM Institute AMOLF, Amsterdam, Netherlands
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127
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Mierke CT. The fundamental role of mechanical properties in the progression of cancer disease and inflammation. REPORTS ON PROGRESS IN PHYSICS. PHYSICAL SOCIETY (GREAT BRITAIN) 2014; 77:076602. [PMID: 25006689 DOI: 10.1088/0034-4885/77/7/076602] [Citation(s) in RCA: 89] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/08/2023]
Abstract
The role of mechanical properties in cancer disease and inflammation is still underinvestigated and even ignored in many oncological and immunological reviews. In particular, eight classical hallmarks of cancer have been proposed, but they still ignore the mechanics behind the processes that facilitate cancer progression. To define the malignant transformation of neoplasms and finally reveal the functional pathway that enables cancer cells to promote cancer progression, these classical hallmarks of cancer require the inclusion of specific mechanical properties of cancer cells and their microenvironment such as the extracellular matrix as well as embedded cells such as fibroblasts, macrophages or endothelial cells. Thus, this review will present current cancer research from a biophysical point of view and will therefore focus on novel physical aspects and biophysical methods to investigate the aggressiveness of cancer cells and the process of inflammation. As cancer or immune cells are embedded in a certain microenvironment such as the extracellular matrix, the mechanical properties of this microenvironment cannot be neglected, and alterations of the microenvironment may have an impact on the mechanical properties of the cancer or immune cells. Here, it is highlighted how biophysical approaches, both experimental and theoretical, have an impact on the classical hallmarks of cancer and inflammation. It is even pointed out how these biophysical approaches contribute to the understanding of the regulation of cancer disease and inflammatory responses after tissue injury through physical microenvironmental property sensing mechanisms. The recognized physical signals are transduced into biochemical signaling events that guide cellular responses, such as malignant tumor progression, after the transition of cancer cells from an epithelial to a mesenchymal phenotype or an inflammatory response due to tissue injury. Moreover, cell adaptation to mechanical alterations, in particular the understanding of mechano-coupling and mechano-regulating functions in cell invasion, appears as an important step in cancer progression and inflammatory response to injuries. This may lead to novel insights into cancer disease and inflammatory diseases and will overcome classical views on cancer and inflammation. In addition, this review will discuss how the physics of cancer and inflammation can help to reveal whether cancer cells will invade connective tissue and metastasize or how leukocytes extravasate and migrate through the tissue. In this review, the physical concepts of cancer progression, including the tissue basement membrane a cancer cell is crossing, its invasion and transendothelial migration as well as the basic physical concepts of inflammatory processes and the cellular responses to the mechanical stress of the microenvironment such as external forces and matrix stiffness, are presented and discussed. In conclusion, this review will finally show how physical measurements can improve classical approaches that investigate cancer and inflammatory diseases, and how these physical insights can be integrated into classical tumor biological approaches.
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Affiliation(s)
- Claudia Tanja Mierke
- Faculty of Physics and Earth Science, Institute of Experimental Physics I, Biological Physics Division, University of Leipzig, Linnéstr. 5, 04103 Leipzig, Germany
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128
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Wells RG. The portal fibroblast: not just a poor man's stellate cell. Gastroenterology 2014; 147:41-7. [PMID: 24814904 PMCID: PMC4090086 DOI: 10.1053/j.gastro.2014.05.001] [Citation(s) in RCA: 66] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2014] [Revised: 05/02/2014] [Accepted: 05/06/2014] [Indexed: 12/12/2022]
Abstract
Portal fibroblasts, the resident fibroblasts of the portal tract, are found in the mesenchyme surrounding the bile ducts. Their roles in liver homeostasis and response to injury are undefined and controversial. Although portal fibroblasts almost certainly give rise to myofibroblasts during the development of biliary fibrosis, recent lineage tracing studies suggest that their contribution to fibrogenesis is limited compared with that of hepatic stellate cells. Other functions of portal fibroblasts include participation in the peribiliary stem cell niche, regulation of cholangiocyte proliferation, and deposition of specific matrix proteins. Portal fibroblasts synthesize elastin and other components of microfibrils; these may serve structural roles, providing stability to ducts and the vasculature under conditions of increased ductal pressure, or could regulate the bioavailability of the fibrogenic transforming growth factor β in response to injury. Viewing portal fibroblasts in the context of fibroblast populations throughout the body and studying their niche-specific roles in matrix deposition and epithelial regulation could yield new insights into their contributions in the normal and injured liver. Understanding the functions of portal fibroblasts will require us to view them as more than just an alternative to hepatic stellate cells in fibrosis.
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Affiliation(s)
- Rebecca G Wells
- Departments of Medicine (GI) and Pathology and Laboratory Medicine, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania.
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129
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Willis AL, Sabeh F, Li XY, Weiss SJ. Extracellular matrix determinants and the regulation of cancer cell invasion stratagems. J Microsc 2014; 251:250-60. [PMID: 23924043 DOI: 10.1111/jmi.12064] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2013] [Accepted: 06/13/2013] [Indexed: 12/13/2022]
Abstract
During development, wound repair and disease-related processes, such as cancer, normal, or neoplastic cell types traffic through the extracellular matrix (ECM), the complex composite of collagens, elastin, glycoproteins, proteoglycans, and glycosaminoglycans that dictate tissue architecture. Current evidence suggests that tissue-invasive processes may proceed by protease-dependent or protease-independent strategies whose selection is not only governed by the characteristics of the motile cell population, but also by the structural properties of the intervening ECM. Herein, we review the mechanisms by which ECM dimensionality, elasticity, crosslinking, and pore size impact patterns of cell invasion. This summary should prove useful when designing new experimental approaches for interrogating invasion programs as well as identifying potential cellular targets for next-generation therapeutics.
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Affiliation(s)
- A L Willis
- Division of Molecular Medicine & Genetics, Department of Internal Medicine, and the Life Sciences Institute, University of Michigan, Ann Arbor, Michigan, USA
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130
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Nonlinear strain stiffening is not sufficient to explain how far cells can feel on fibrous protein gels. Biophys J 2014; 105:11-20. [PMID: 23823219 DOI: 10.1016/j.bpj.2013.05.032] [Citation(s) in RCA: 82] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2012] [Revised: 05/06/2013] [Accepted: 05/10/2013] [Indexed: 01/15/2023] Open
Abstract
Recent observations suggest that cells on fibrous extracellular matrix materials sense mechanical signals over much larger distances than they do on linearly elastic synthetic materials. In this work, we systematically investigate the distance fibroblasts can sense a rigid boundary through fibrous gels by quantifying the spread areas of human lung fibroblasts and 3T3 fibroblasts cultured on sloped collagen and fibrin gels. The cell areas gradually decrease as gel thickness increases from 0 to 150 μm, with characteristic sensing distances of >65 μm below fibrin and collagen gels, and spreading affected on gels as thick as 150 μm. These results demonstrate that fibroblasts sense deeper into collagen and fibrin gels than they do into polyacrylamide gels, with the latter exhibiting characteristic sensing distances of <5 μm. We apply finite-element analysis to explore the role of strain stiffening, a characteristic mechanical property of collagen and fibrin that is not observed in polyacrylamide, in facilitating mechanosensing over long distances. Our analysis shows that the effective stiffness of both linear and nonlinear materials sharply increases once the thickness is reduced below 5 μm, with only a slight enhancement in sensitivity to depth for the nonlinear material at very low thickness and high applied traction. Multiscale simulations with a simplified geometry predict changes in fiber alignment deep into the gel and a large increase in effective stiffness with a decrease in substrate thickness that is not predicted by nonlinear elasticity. These results suggest that the observed cell-spreading response to gel thickness is not explained by the nonlinear strain-stiffening behavior of the material alone and is likely due to the fibrous nature of the proteins.
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131
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Reinhardt JW, Krakauer DA, Gooch KJ. Complex matrix remodeling and durotaxis can emerge from simple rules for cell-matrix interaction in agent-based models. J Biomech Eng 2014; 135:71003. [PMID: 23722647 DOI: 10.1115/1.4024463] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2012] [Accepted: 05/08/2013] [Indexed: 11/08/2022]
Abstract
Using a top-down approach, an agent-based model was developed within NetLogo where cells and extracellular matrix (ECM) fibers were composed of multiple agents to create deformable structures capable of exerting, reacting to, and transmitting mechanical force. At the beginning of the simulation, long fibers were randomly distributed and cross linked. Throughout the simulation, imposed rules allowed cells to exert traction forces by extending pseudopodia, binding to fibers and pulling them towards the cell. Simulated cells remodeled the fibrous matrix to change both the density and alignment of fibers and migrated within the matrix in ways that are consistent with previous experimental work. For example, cells compacted the matrix in their pericellular regions much more than the average compaction experienced for the entire matrix (696% versus 21%). Between pairs of cells, the matrix density increased (by 92%) and the fibers became more aligned (anisotropy index increased from 0.45 to 0.68) in the direction parallel to a line connecting the two cells, consistent with the "lines of tension" observed in experiments by others. Cells migrated towards one another at an average rate of ∼0.5 cell diameters per 10,000 arbitrary units (AU); faster migration occurred in simulations where the fiber density in the intercellular area was greater. To explore the potential contribution of matrix stiffness gradients in the observed migration (i.e., durotaxis), the model was altered to contain a regular lattice of fibers possessing a stiffness gradient and just a single cell. In these simulations cells migrated preferentially in the direction of increasing stiffness at a rate of ∼2 cell diameter per 10,000 AU. This work demonstrates that matrix remodeling and durotaxis, both complex phenomena, might be emergent behaviors based on just a few rules that control how a cell can interact with a fibrous ECM.
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Affiliation(s)
- James W Reinhardt
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH 43210, USA
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Mohammadi H, Janmey PA, McCulloch CA. Lateral boundary mechanosensing by adherent cells in a collagen gel system. Biomaterials 2013; 35:1138-49. [PMID: 24215732 DOI: 10.1016/j.biomaterials.2013.10.059] [Citation(s) in RCA: 47] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Accepted: 10/19/2013] [Indexed: 01/17/2023]
Abstract
Cell adhesion responses to in-depth physical properties such as substrate roughness and topography are well described but little is known about the influence of lateral physical cues such as tissue boundaries on the function of adherent cells. Accordingly, we developed a model system to examine remote cell sensing of lateral boundaries. The model employs floating thin collagen gels supported by rigid grids of varying widths. The dynamics, lengths, and numbers of cell extensions were regulated by grid opening size, which in turn determined the distance of cells from rigid physical boundaries. In smaller grids (200 μm and 500 μm wide), cell-induced deformation fields extended to, and were resisted by, the grid boundaries. However, in larger grids (1700 μm wide), the deformation field did not extend to the grid boundaries, which strongly affected the mean length and number of cell extensions (∼60% reduction). The generation of cell extensions in collagen gels required expression of the β1 integrin, focal adhesion kinase and actomyosin activity. We conclude that the presence of physical boundaries interrupts the process of cell-mediated collagen compaction and fiber alignment in the collagen matrix and enhances the formation of cell extensions. This new cell culture platform provides a geometry that more closely approximates the native basement membrane and will help to elucidate the roles of cell extensions and lateral mechanosensing on extracellular matrix remodeling by invasion and degradation.
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Affiliation(s)
- Hamid Mohammadi
- Matrix Dynamics Group, University of Toronto, Toronto, ON, Canada.
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Wen Q, Janmey PA. Effects of non-linearity on cell-ECM interactions. Exp Cell Res 2013; 319:2481-9. [PMID: 23748051 PMCID: PMC3930572 DOI: 10.1016/j.yexcr.2013.05.017] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2013] [Accepted: 05/21/2013] [Indexed: 01/17/2023]
Abstract
Filamentous biopolymers such as F-actin, vimentin, fibrin and collagen that form networks within the cytoskeleton or the extracellular matrix have unusual rheological properties not present in most synthetic soft materials that are used as cell substrates or scaffolds for tissue engineering. Gels formed by purified filamentous biopolymers are often strain stiffening, with an elastic modulus that can increase an order of magnitude at moderate strains that are relevant to cell and tissue deformation in vivo. This review summarizes some experimental studies of non-linear rheology in biopolymer gels, discusses possible molecular mechanisms that account for strain stiffening, and explores the possible relevance of non-linear rheology to the interactions between cell and extracellular matrices.
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Affiliation(s)
- Qi Wen
- Department of Physics, Worcester Polytechnic Institute, 100 Institute Road, Worcester, MA 01609
| | - Paul A. Janmey
- Institute for Medicine and Engineering, University of Pennsylvania, 1010 Vagelos Laboratories, 3340 Smith Walk, Philadelphia, PA 19104
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