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Xie Y, Chen D, Jiang K, Song L, Qian N, Du Y, Yang Y, Wang F, Chen T. Hair shaft miniaturization causes stem cell depletion through mechanosensory signals mediated by a Piezo1-calcium-TNF-α axis. Cell Stem Cell 2021; 29:70-85.e6. [PMID: 34624205 DOI: 10.1016/j.stem.2021.09.009] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2021] [Revised: 07/19/2021] [Accepted: 09/13/2021] [Indexed: 12/17/2022]
Abstract
In aging, androgenic alopecia, and genetic hypotrichosis disorders, hair shaft miniaturization is often associated with hair follicle stem cell (HFSC) loss. However, the mechanism causing this stem cell depletion in vivo remains elusive. Here we show that hair shaft loss or a reduction in diameter shrinks the physical niche size, which results in mechanical compression of HFSCs and their apoptotic loss. Mechanistically, cell compression activates the mechanosensitive channel Piezo1, which triggers calcium influx. This confers tumor necrosis factor alpha (TNF-α) sensitivity in a hair-cycle-dependent manner in otherwise resistant HFSCs and induces ectopic apoptosis. Persistent hair shaft miniaturization during aging and genetic hypotrichosis disorders causes long-term HFSC loss by inducing continuous ectopic apoptosis through Piezo1. Our results identify an unconventional role of the inert hair shaft structure as a functional niche component governing HFSC survival and reveal a mechanosensory axis that regulates physical-niche-atrophy-induced stem cell depletion in vivo.
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Affiliation(s)
- Yuhua Xie
- China Agricultural University, Beijing, China; National Institute of Biological Sciences, Beijing, China
| | - Daoming Chen
- National Institute of Biological Sciences, Beijing, China
| | - Kaiju Jiang
- National Institute of Biological Sciences, Beijing, China
| | - Lifang Song
- National Institute of Biological Sciences, Beijing, China
| | - Nannan Qian
- National Institute of Biological Sciences, Beijing, China
| | - Yingxue Du
- National Institute of Biological Sciences, Beijing, China
| | - Yong Yang
- Institute of Dermatology, Chinese Academy of Medical Sciences and Peking Union Medical College, Nanjing, China
| | - Fengchao Wang
- National Institute of Biological Sciences, Beijing, China
| | - Ting Chen
- National Institute of Biological Sciences, Beijing, China; Tsinghua Institute of Multidisciplinary Biomedical Research, Tsinghua University, Beijing, China.
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2
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Nossa R, Costa J, Cacopardo L, Ahluwalia A. Breathing in vitro: Designs and applications of engineered lung models. J Tissue Eng 2021; 12:20417314211008696. [PMID: 33996022 PMCID: PMC8107677 DOI: 10.1177/20417314211008696] [Citation(s) in RCA: 16] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2020] [Accepted: 03/22/2021] [Indexed: 12/11/2022] Open
Abstract
The aim of this review is to provide a systematic design guideline to users, particularly engineers interested in developing and deploying lung models, and biologists seeking to identify a suitable platform for conducting in vitro experiments involving pulmonary cells or tissues. We first discuss the state of the art on lung in vitro models, describing the most simplistic and traditional ones. Then, we analyze in further detail the more complex dynamic engineered systems that either provide mechanical cues, or allow for more predictive exposure studies, or in some cases even both. This is followed by a dedicated section on microchips of the lung. Lastly, we present a critical discussion of the different characteristics of each type of system and the criteria which may help researchers select the most appropriate technology according to their specific requirements. Readers are encouraged to refer to the tables accompanying the different sections where comprehensive and quantitative information on the operating parameters and performance of the different systems reported in the literature is provided.
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3
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Li X, Garcia-Elias A, Benito B, Nattel S. The effects of cardiac stretch on atrial fibroblasts: Analysis of the evidence and potential role in atrial fibrillation. Cardiovasc Res 2021; 118:440-460. [PMID: 33576384 DOI: 10.1093/cvr/cvab035] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2020] [Revised: 11/27/2020] [Accepted: 02/09/2021] [Indexed: 01/06/2023] Open
Abstract
Atrial fibrillation (AF) is an important clinical problem. Chronic pressure/volume overload of the atria promotes AF, particularly via enhanced extracellular matrix (ECM) accumulation manifested as tissue fibrosis. Loading of cardiac cells causes cell-stretch that is generally considered to promote fibrosis by directly activating fibroblasts, the key cell-type responsible for ECM-production. The primary purpose of this article is to review the evidence regarding direct effects of stretch on cardiac fibroblasts, specifically: (i) the similarities and differences among studies in observed effects of stretch on cardiac-fibroblast function; (ii) the signaling-pathways implicated; and (iii) the factors that affect stretch-related phenotypes. Our review summarizes the most important findings and limitations in this area and gives an overview of clinical data and animal models related to cardiac stretch, with particular emphasis on the atria. We suggest that the evidence regarding direct fibroblast activation by stretch is weak and inconsistent, in part because of variability among studies in key experimental conditions that govern the results. Further work is needed to clarify whether, in fact, stretch induces direct activation of cardiac fibroblasts and if so, to elucidate the determining factors to ensure reproducible results. If mechanical load on fibroblasts proves not to be clearly profibrotic by direct actions, other mechanisms like paracrine influences, the effects of systemic mediators and/or the direct consequences of myocardial injury or death, might account for the link between cardiac stretch and fibrosis. Clarity in this area is needed to improve our understanding of AF pathophysiology and assist in therapeutic development.
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Affiliation(s)
- Xixiao Li
- Department of Medicine and Research Center, Montreal Heart Institute, Montreal, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada
| | - Anna Garcia-Elias
- Department of Medicine and Research Center, Montreal Heart Institute, Montreal, Canada
| | - Begoña Benito
- Vascular Biology and Metabolism Program, Vall d'Hebrón Research Institute (VHIR), Barcelona, Spain.,Cardiology Department, Hospital Universitari Vall d'Hebrón, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Stanley Nattel
- Department of Medicine and Research Center, Montreal Heart Institute, Montreal, Canada.,Department of Pharmacology and Therapeutics, McGill University, Montreal, Canada.,Department of Pharmacology and Physiology of the Université de Montréal Faculty of Medicine, Montreal, Canada.,Institute of Pharmacology, West German Heart and Vascular Center, Faculty of Medicine, University Duisburg-Essen, Essen, Germany.,IHU LIRYC and Fondation Bordeaux Université, Bordeaux, France
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4
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Katzengold R, Orlov A, Gefen A. A novel system for dynamic stretching of cell cultures reveals the mechanobiology for delivering better negative pressure wound therapy. Biomech Model Mechanobiol 2020; 20:193-204. [PMID: 32803464 DOI: 10.1007/s10237-020-01377-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Accepted: 08/05/2020] [Indexed: 12/20/2022]
Abstract
Serious wounds, both chronic and acute (e.g., surgical), are among the most common, expensive and difficult-to-treat health problems. Negative pressure wound therapy (NPWT) is considered a mainstream procedure for treating both wound types. Soft tissue deformation stimuli are the crux of NPWT, enhancing cell proliferation and migration from peri-wound tissues which contributes to healing. We developed a dynamic stretching device (DSD) contained in a miniature incubator for applying controlled deformations to fibroblast wound assays. Prior to the stretching experiments, fibroblasts were seeded in 6-well culture plates with elastic substrata and let to reach confluency. Squashing damage was then induced at the culture centers, and the DSD was activated to deliver stretching regimes that represented common clinical NPWT protocols at two peak strain levels, 0.5% and 3%. Analyses of the normalized maximal migration rate (MMR) data for the collective cell movement revealed that for the 3% strain level, the normalized MMR of cultures subjected to a 0.1 Hz stretch frequency regime was ~ 1.4 times and statistically significantly greater (p < 0.05) than that of the cultures subjected to no-stretch (control) or to static stretch (2nd control). Correspondingly, analysis of the time to gap closure data indicated that the closure time of the wound assays subjected to the 0.1 Hz regime was ~ 30% shorter than that of the cultures subjected to the control regimes (p < 0.05). Other simulated NPWT protocols did not emerge as superior to the controls. The present method and system are a powerful platform for further revealing the mechanobiology of NPWT and for improving this technology.
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Affiliation(s)
- Rona Katzengold
- The Herbert J. Berman Chair in Vascular Bioengineering, Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Alexey Orlov
- The Herbert J. Berman Chair in Vascular Bioengineering, Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, 6997801, Tel Aviv, Israel
| | - Amit Gefen
- The Herbert J. Berman Chair in Vascular Bioengineering, Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, 6997801, Tel Aviv, Israel.
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Mayer CR, Arsenovic PT, Bathula K, Denis KB, Conway DE. Characterization of 3D Printed Stretching Devices for Imaging Force Transmission in Live-Cells. Cell Mol Bioeng 2019; 12:289-300. [PMID: 31719915 DOI: 10.1007/s12195-019-00579-y] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2018] [Accepted: 06/07/2019] [Indexed: 12/26/2022] Open
Abstract
Introduction Cell stretch is a method which can rapidly apply mechanical force through cell-matrix and cell-cell adhesions and can be utilized to better understand underlying biophysical questions related to intracellular force transmission and mechanotransduction. Methods 3D printable stretching devices suitable for live-cell fluorescent imaging were designed using finite element modeling and validated experimentally. These devices were then used along with FRET based nesprin-2G force sensitive biosensors as well as live cell fluorescent staining to understand how the nucleus responds to externally applied mechanical force in cells with both intact LINC (linker of nucleoskeleton and cytoskeleton) complex and cells with the LINC complex disrupted using expression of dominant negative KASH protein. Results The devices were shown to provide a larger strain ranges (300% uniaxial and 60% biaxial) than currently available commercial or academic designs we are aware of. Under uniaxial deformation, the deformation of the nucleus of NIH 3T3 cells per unit of imposed cell strain was shown to be approximately 50% higher in control cells compared to cells with a disrupted LINC complex. Under biaxial deformation, MDCK II cells showed permanent changes in the nuclear morphology as well as actin organization upon unloading, indicating that failure, plastic deformation, or remodeling of the cytoskeleton is occurring in response to the applied stretch. Conclusion Development and open distribution of low-cost, 3D-printable uniaxial and biaxial cell stretching devices compatible with live-cell fluorescent imaging allows a wider range of researchers to investigate mechanical influences on biological questions with only a minimal investment of resources.
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Affiliation(s)
- Carl R Mayer
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284 USA
| | - Paul T Arsenovic
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284 USA
| | - Kranthidhar Bathula
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284 USA
| | - Kevin B Denis
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284 USA
| | - Daniel E Conway
- Department of Biomedical Engineering, Virginia Commonwealth University, Richmond, VA 23284 USA
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Vroemen PAMM, Gorgels TGMF, Webers CAB, de Boer J. Modeling the Mechanical Parameters of Glaucoma. TISSUE ENGINEERING PART B-REVIEWS 2019; 25:412-428. [PMID: 31088331 DOI: 10.1089/ten.teb.2019.0044] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Glaucoma is a major eye disease characterized by a progressive loss of retinal ganglion cells (RGCs). Biomechanical forces as a result of hydrostatic pressure and strain play a role in this disease. Decreasing intraocular pressure is the only available therapy so far, but is not always effective and does not prevent blindness in many cases. There is a need for drugs that protect RGCs from dying in glaucoma; to develop these, we need valid glaucoma and drug screening models. Since in vivo models are unsuitable for screening purposes, we focus on in vitro and ex vivo models in this review. Many groups have studied pressure and strain model systems to mimic glaucoma, to investigate the molecular and cellular events leading to mechanically induced RGC death. Therefore, the focus of this review is on the different mechanical model systems used to mimic the biomechanical forces in glaucoma. Most models use either cell or tissue strain, or fluid- or gas-controlled hydrostatic pressure application and apply it to the relevant cell types such as trabecular meshwork cells, optic nerve head astrocytes, and RGCs, but also to entire eyes. New model systems are warranted to study concepts and test experimental compounds for the development of new drugs to protect vision in glaucoma patients. Impact Statement The outcome of currently developed models to investigate mechanically induced retinal ganglion cell death by applying different mechanical strains varies widely. This suggests that a robust glaucoma model has not been developed yet. However, a comprehensive overview of current developments is not available. In this review, we have therefore assessed what has been done before and summarized the available knowledge in the field, which can be used to develop improved models for glaucoma research.
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Affiliation(s)
- Pascal A M M Vroemen
- University Eye Clinic Maastricht UMC+, Maastricht University Medical Centre+, Maastricht, The Netherlands.,Department of Complex Tissue Regeneration (CTR), MERLN Institute for Technology-Inspired Regenerative Medicine, Maastricht University, Maastricht, The Netherlands.,Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands
| | - Theo G M F Gorgels
- University Eye Clinic Maastricht UMC+, Maastricht University Medical Centre+, Maastricht, The Netherlands.,Netherlands Institute for Neuroscience, Amsterdam, The Netherlands
| | - Carroll A B Webers
- University Eye Clinic Maastricht UMC+, Maastricht University Medical Centre+, Maastricht, The Netherlands
| | - Jan de Boer
- Department of Biomedical Engineering, Eindhoven University of Technology, Eindhoven, The Netherlands.,Institute for Complex Molecular Structures, Eindhoven University of Technology, Eindhoven, The Netherlands
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7
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He J, Xu Y, Yang L, Xia G, Deng N, Yang Y, Tian Y, Fu Z, Huang Y. Regulation of inward rectifier potassium current ionic channel remodeling by AT1
-Calcineurin-NFAT signaling pathway in stretch-induced hypertrophic atrial myocytes. Cell Biol Int 2018; 42:1149-1159. [PMID: 29719087 DOI: 10.1002/cbin.10983] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Accepted: 04/28/2018] [Indexed: 12/19/2022]
Affiliation(s)
- Jionghong He
- Department of Cardiology; Guizhou Provincial People's Hospital; Guiyang 550002 China
| | - Yanan Xu
- Department of Rehabilitation Medicine; Xiaotangshan Hospital; Beijing 102211 China
| | - Long Yang
- Department of Cardiology; Guizhou Provincial People's Hospital; Guiyang 550002 China
| | - Guiling Xia
- Department of Cardiology; Guizhou Provincial People's Hospital; Guiyang 550002 China
| | - Na Deng
- Department of Cardiology; Guizhou Provincial People's Hospital; Guiyang 550002 China
| | - Yongyao Yang
- Department of Cardiology; Guizhou Provincial People's Hospital; Guiyang 550002 China
| | - Ye Tian
- Department of Cardiology; Guizhou Provincial People's Hospital; Guiyang 550002 China
| | - Zenan Fu
- Department of Cardiology; Guizhou Provincial People's Hospital; Guiyang 550002 China
| | - Yongqi Huang
- Department of Cardiology; Guizhou Provincial People's Hospital; Guiyang 550002 China
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8
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Live cell imaging reveals focal adhesions mechanoresponses in mammary epithelial cells under sustained equibiaxial stress. Sci Rep 2018; 8:9788. [PMID: 29955093 PMCID: PMC6023913 DOI: 10.1038/s41598-018-27948-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Accepted: 06/08/2018] [Indexed: 12/22/2022] Open
Abstract
Mechanical stimuli play a key role in many cell functions such as proliferation, differentiation and migration. In the mammary gland, mechanical signals such as the distension of mammary epithelial cells due to udder filling are proposed to be directly involved during lactation and involution. However, the evolution of focal adhesions -specialized multiprotein complexes that mechanically connect cells with the extracellular matrix- during the mammary gland development, as well as the influence of the mechanical stimuli involved, remains unclear. Here we present the use of an equibiaxial stretching device for exerting a sustained normal strain to mammary epithelial cells while quantitatively assessing cell responses by fluorescence imaging techniques. Using this approach, we explored changes in focal adhesion dynamics in HC11 mammary cells in response to a mechanical sustained stress, which resembles the physiological stimuli. We studied the relationship between a global stress and focal adhesion assembly/disassembly, observing an enhanced persistency of focal adhesions under strain as well as an increase in their size. At a molecular level, we evaluated the mechanoresponses of vinculin and zyxin, two focal adhesion proteins postulated as mechanosensors, observing an increment in vinculin molecular tension and a slower zyxin dynamics while increasing the applied normal strain.
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9
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Parsa H, Wang BZ, Vunjak-Novakovic G. A microfluidic platform for the high-throughput study of pathological cardiac hypertrophy. LAB ON A CHIP 2017; 17:3264-3271. [PMID: 28832065 DOI: 10.1039/c7lc00415j] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
Current in vitro models fall short in deciphering the mechanisms of cardiac hypertrophy induced by volume overload. We developed a pneumatic microfluidic platform for high-throughput studies of cardiac hypertrophy that enables repetitive (hundreds of thousands of times) and robust (over several weeks) manipulation of cardiac μtissues. The platform is reusable for stable and reproducible mechanical stimulation of cardiac μtissues (each containing only 5000 cells). Heterotypic and homotypic μtissues produced in the device were pneumatically loaded in a range of regimes, with real-time on-chip analysis of tissue phenotypes. Concentrated loading of the three-dimensional cardiac tissue faithfully recapitulated the pathology of volume overload seen in native heart tissue. Sustained volume overload of μtissues was sufficient to induce pathological cardiac remodeling associated with upregulation of the fetal gene program, in a dose-dependent manner.
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Affiliation(s)
- Hesam Parsa
- Department of Biomedical Engineering, Columbia University, 622 west 168th St., New York, NY 10032, USA.
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10
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Wang Y, Dang Z, Cui W, Yang L. Mechanical stretch and hypoxia inducible factor-1 alpha affect the vascular endothelial growth factor and the connective tissue growth factor in cultured ACL fibroblasts. Connect Tissue Res 2017; 58:407-413. [PMID: 27600173 DOI: 10.1080/03008207.2016.1231179] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
PURPOSES The adult human anterior cruciate ligament (ACL) has poor functional healing response. Hypoxia plays an important role in regulating the microenvironment of the joint cavity after ACL injury, however, its role in mechanical injury is yet to be examined fully in ACL fibroblasts. In this study, we used CoCl2 to induce Hypoxia-inducible factor-1α (HIF-1α) in our experimental model to study its affect on matrix metalloproteinase-2 (MMP-2), vascular endothelial growth factor (VEGF), and connective tissue growth factor (CTGF) expression in ACL fibroblasts after mechanical stretch. MATERIALS AND METHODS Cell treatments were performed in the stretch chamber in all experimental groups. Quantitative real-time PCR was used to check mRNA expression levels of MMP-2, CTGF, VEGF, and HIF-1α. Western blot was used to detect the HIF-1α production. Enzyme-Linked immunosorbent assay was performed to check the VEGF and CTGF protein contents in supernatant. MMP-2 activity was assayed by gelatin zymography. RESULTS The real-time PCR results show that mechanical stretch or CoCl2 treatment increases the expression of MMP-2, VEGF, CTGF, and HIF-1α; however, the combined effects of mechanical stretch and CoCl2-induced HIF-1α increased MMP-2 production but decreased the VEGF and CTGF expression, compared to the CoCl2 treatment group alone. Western blot analysis and ELISA also confirmed these results. CONCLUSIONS Our results demonstrated that mechanical stretch and CoCl2-induced HIF-1α together increased the level of MMP-2 and decreased the levels of VEGF and CTGF in cultured ACL fibroblasts. The differential expression and production of HIF-1α, VEGF, MMP-2, and CTGF might help to explain the poor healing ability of ACL.
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Affiliation(s)
- Yequan Wang
- a Institute of Forensic Medicine and Laboratory Medicine , Jining Medical University , Jining , China.,b Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College , Chongqing University , Chongqing , China.,c "111" Biomechanics and Tissue Repair Laboratory, Bioengineering College , Chongqing University , Chongqing , China
| | - Zhen Dang
- a Institute of Forensic Medicine and Laboratory Medicine , Jining Medical University , Jining , China
| | - Wen Cui
- a Institute of Forensic Medicine and Laboratory Medicine , Jining Medical University , Jining , China
| | - Li Yang
- b Key Laboratory of Biorheological Science and Technology, Ministry of Education, Bioengineering College , Chongqing University , Chongqing , China.,c "111" Biomechanics and Tissue Repair Laboratory, Bioengineering College , Chongqing University , Chongqing , China
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11
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Abdalrahman T, Dubuis L, Green J, Davies N, Franz T. Cellular mechanosensitivity to substrate stiffness decreases with increasing dissimilarity to cell stiffness. Biomech Model Mechanobiol 2017; 16:2063-2075. [PMID: 28733924 DOI: 10.1007/s10237-017-0938-y] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/02/2017] [Accepted: 07/11/2017] [Indexed: 01/07/2023]
Abstract
Computational modelling has received increasing attention to investigate multi-scale coupled problems in micro-heterogeneous biological structures such as cells. In the current study, we investigated for a single cell the effects of (1) different cell-substrate attachment (2) and different substrate modulus [Formula: see text] on intracellular deformations. A fibroblast was geometrically reconstructed from confocal micrographs. Finite element models of the cell on a planar substrate were developed. Intracellular deformations due to substrate stretch of [Formula: see text], were assessed for: (1) cell-substrate attachment implemented as full basal contact (FC) and 124 focal adhesions (FA), respectively, and [Formula: see text]140 KPa and (2) [Formula: see text], 140, 1000, and 10,000 KPa, respectively, and FA attachment. The largest strains in cytosol, nucleus and cell membrane were higher for FC (1.35[Formula: see text], 0.235[Formula: see text] and 0.6[Formula: see text]) than for FA attachment (0.0952[Formula: see text], 0.0472[Formula: see text] and 0.05[Formula: see text]). For increasing [Formula: see text], the largest maximum principal strain was 4.4[Formula: see text], 5[Formula: see text], 5.3[Formula: see text] and 5.3[Formula: see text] in the membrane, 9.5[Formula: see text], 1.1[Formula: see text], 1.2[Formula: see text] and 1.2[Formula: see text] in the cytosol, and 4.5[Formula: see text], 5.3[Formula: see text], 5.7[Formula: see text] and 5.7[Formula: see text] in the nucleus. The results show (1) the importance of representing FA in cell models and (2) higher cellular mechanical sensitivity for substrate stiffness changes in the range of cell stiffness. The latter indicates that matching substrate stiffness to cell stiffness, and moderate variation of the former is very effective for controlled variation of cell deformation. The developed methodology is useful for parametric studies on cellular mechanics to obtain quantitative data of subcellular strains and stresses that cannot easily be measured experimentally.
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Affiliation(s)
- Tamer Abdalrahman
- Division of Biomedical Engineering, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Observatory, South Africa
| | - Laura Dubuis
- Division of Biomedical Engineering, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Observatory, South Africa
| | - Jason Green
- Cardiovascular Research Unit, Chris Barnard Division of Cardiothoracic Surgery, University of Cape Town, Observatory, South Africa
| | - Neil Davies
- Cardiovascular Research Unit, Chris Barnard Division of Cardiothoracic Surgery, University of Cape Town, Observatory, South Africa
| | - Thomas Franz
- Division of Biomedical Engineering, Department of Human Biology, Faculty of Health Sciences, University of Cape Town, Observatory, South Africa. .,Bioengineering Science Research Group, Engineering Sciences, Faculty of Engineering and the Environment, University of Southampton, Southampton, UK.
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12
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Xie J, Wang CL, Yang W, Wang J, Chen C, Zheng L, Sung KP, Zhou X. Modulation of MMP-2 and MMP-9 through connected pathways and growth factors is critical for extracellular matrix balance of intra-articular ligaments. J Tissue Eng Regen Med 2017; 12:e550-e565. [PMID: 27684403 DOI: 10.1002/term.2325] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2015] [Revised: 07/29/2016] [Accepted: 09/26/2016] [Indexed: 02/05/2023]
Affiliation(s)
- Jing Xie
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology; Sichuan University; Chengdu Sichuan Province China
| | - Chun-Li Wang
- Key Laboratory of Biorheological Science and Technology, Bioengineering College; Chongqing University; Chongqing China
| | - Wenbin Yang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology; Sichuan University; Chengdu Sichuan Province China
| | - Jue Wang
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology; Sichuan University; Chengdu Sichuan Province China
| | - Cheng Chen
- Centre for Joint Surgery, Southwest Hospital; Third Military Medical University; Chongqing China
| | - Liwei Zheng
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology; Sichuan University; Chengdu Sichuan Province China
| | - K.L. Paul Sung
- Key Laboratory of Biorheological Science and Technology, Bioengineering College; Chongqing University; Chongqing China
| | - Xuedong Zhou
- State Key Laboratory of Oral Diseases, West China Hospital of Stomatology; Sichuan University; Chengdu Sichuan Province China
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13
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Agrawal A, Chen H, Kim H, Zhu B, Adetiba O, Miranda A, Cristian Chipara A, Ajayan PM, Jacot JG, Verduzco R. Electromechanically Responsive Liquid Crystal Elastomer Nanocomposites for Active Cell Culture. ACS Macro Lett 2016; 5:1386-1390. [PMID: 35651216 DOI: 10.1021/acsmacrolett.6b00554] [Citation(s) in RCA: 62] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Liquid crystal elastomers (LCEs) are unique among shape-responsive materials in that they exhibit large and reversible shape changes and can respond to a variety of stimuli. However, only a handful of studies have explored LCEs for biomedical applications. Here, we demonstrate that LCE nanocomposites (LCE-NCs) exhibit a fast and reversible electromechanical response and can be employed as dynamic substrates for cell culture. A two-step method for preparing conductive LCE-NCs is described, which produces materials that exhibit rapid (response times as fast at 0.6 s), large-amplitude (contraction by up to 30%), and fully reversible shape changes (stable to over 5000 cycles) under externally applied voltages (5-40 V). The electromechanical response of the LCE-NCs is tunable through variation of the electrical potential and LCE-NC composition. We utilize conductive LCE-NCs as responsive substrates to culture neonatal rat ventricular myocytes (NRVM) and find that NRVM remain viable on both stimulated and static LCE-NC substrates. These materials provide a reliable and simple route to materials that exhibit a fast, reversible, and large-amplitude electromechanical response.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Jeffrey G. Jacot
- Congenital
Heart Surgery, Texas Children’s Hospital, Houston, Texas 77030, United States
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14
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Stretch Injury of Human Induced Pluripotent Stem Cell Derived Neurons in a 96 Well Format. Sci Rep 2016; 6:34097. [PMID: 27671211 PMCID: PMC5037451 DOI: 10.1038/srep34097] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Accepted: 09/07/2016] [Indexed: 01/27/2023] Open
Abstract
Traumatic brain injury (TBI) is a major cause of mortality and morbidity with limited therapeutic options. Traumatic axonal injury (TAI) is an important component of TBI pathology. It is difficult to reproduce TAI in animal models of closed head injury, but in vitro stretch injury models reproduce clinical TAI pathology. Existing in vitro models employ primary rodent neurons or human cancer cell line cells in low throughput formats. This in vitro neuronal stretch injury model employs human induced pluripotent stem cell-derived neurons (hiPSCNs) in a 96 well format. Silicone membranes were attached to 96 well plate tops to create stretchable, culture substrates. A custom-built device was designed and validated to apply repeatable, biofidelic strains and strain rates to these plates. A high content approach was used to measure injury in a hypothesis-free manner. These measurements are shown to provide a sensitive, dose-dependent, multi-modal description of the response to mechanical insult. hiPSCNs transition from healthy to injured phenotype at approximately 35% Lagrangian strain. Continued development of this model may create novel opportunities for drug discovery and exploration of the role of human genotype in TAI pathology.
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Ma SP, Vunjak-Novakovic G. Tissue-Engineering for the Study of Cardiac Biomechanics. J Biomech Eng 2016; 138:021010. [PMID: 26720588 PMCID: PMC4845250 DOI: 10.1115/1.4032355] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Indexed: 12/13/2022]
Abstract
The notion that both adaptive and maladaptive cardiac remodeling occurs in response to mechanical loading has informed recent progress in cardiac tissue engineering. Today, human cardiac tissues engineered in vitro offer complementary knowledge to that currently provided by animal models, with profound implications to personalized medicine. We review here recent advances in the understanding of the roles of mechanical signals in normal and pathological cardiac function, and their application in clinical translation of tissue engineering strategies to regenerative medicine and in vitro study of disease.
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Affiliation(s)
- Stephen P. Ma
- Department of Biomedical Engineering,
Columbia University,
622 West 168th Street,
VC12-234,
New York, NY 10032
e-mail:
| | - Gordana Vunjak-Novakovic
- Department of Biomedical Engineering
and Department of Medicine,
Columbia University,
622 West 168th Street,
VC12-234,
New York, NY 10032
e-mail:
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16
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Sears C, Kaunas R. The many ways adherent cells respond to applied stretch. J Biomech 2015; 49:1347-1354. [PMID: 26515245 DOI: 10.1016/j.jbiomech.2015.10.014] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2015] [Revised: 10/05/2015] [Accepted: 10/10/2015] [Indexed: 10/24/2022]
Abstract
Cells in various tissues are subjected to mechanical stress and strain that have profound effects on cell architecture and function. The specific response of the cell to applied strain depends on multiple factors, including cell contractility, spatial and temporal strain pattern, and substrate dimensionality and rigidity. Recent work has demonstrated that the cell response to applied strain depends on a complex combination of these factors, but the way these factors interact to elicit a specific response is not intuitive. We submit that an understanding of the integrated response of a cell to these factors will provide new insight into mechanobiology and contribute to the effective design of deformable engineered scaffolds meant to provide appropriate mechanical cues to the resident cells.
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Affiliation(s)
- Candice Sears
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843-3120, USA
| | - Roland Kaunas
- Department of Biomedical Engineering, Texas A&M University, College Station, TX 77843-3120, USA.
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17
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de Oliveira BL, Pfeiffer ER, Sundnes J, Wall ST, McCulloch AD. Increased cell membrane capacitance is the dominant mechanism of stretch-dependent conduction slowing in the rabbit heart: a computational study. Cell Mol Bioeng 2015; 8:237-246. [PMID: 27087858 DOI: 10.1007/s12195-015-0384-9] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022] Open
Abstract
Volume loading of the cardiac ventricles is known to slow electrical conduction in the rabbit heart, but the mechanisms remain unclear. Previous experimental and modeling studies have investigated some of these mechanisms, including stretch-activated membrane currents, reduced gap junctional conductance, and altered cell membrane capacitance. In order to quantify the relative contributions of these mechanisms, we combined a monomain model of rabbit ventricular electrophysiology with a hyperelastic model of passive ventricular mechanics. First, a simplified geometric model with prescribed homogeneous deformation was used to fit model parameters and characterize individual MEF mechanisms, and showed good qualitative agreement with experimentally measured strain-CV relations. A 3D model of the rabbit left and right ventricles was then compared with experimental measurements from optical electrical mapping studies in the isolated rabbit heart. The model was inflated to an end-diastolic pressure of 30 mmHg, resulting in epicardial strains comparable to those measured in the anterior left ventricular free wall. While the effects of stretch activated channels did alter epicardial conduction velocity, an increase in cellular capacitance was required to explain previously reported experimental results. The new results suggest that for large strains, various mechanisms can combine and produce a biphasic relationship between strain and conduction velocity. However, at the moderate strains generated by high end-diastolic pressure, a stretch-induced increase in myocyte membrane capacitance is the dominant driver of conduction slowing during ventricular volume loading.
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Affiliation(s)
| | | | - Joakim Sundnes
- Simula Research Laboratory, Lysaker, Norway; Department of Informatics, University of Oslo, Norway
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18
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Lee J, Baker AB. Computational analysis of fluid flow within a device for applying biaxial strain to cultured cells. J Biomech Eng 2015; 137:051006. [PMID: 25611013 DOI: 10.1115/1.4029638] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Indexed: 11/08/2022]
Abstract
In vitro systems for applying mechanical strain to cultured cells are commonly used to investigate cellular mechanotransduction pathways in a variety of cell types. These systems often apply mechanical forces to a flexible membrane on which cells are cultured. A consequence of the motion of the membrane in these systems is the generation of flow and the unintended application of shear stress to the cells. We recently described a flexible system for applying mechanical strain to cultured cells, which uses a linear motor to drive a piston array to create biaxial strain within multiwell culture plates. To better understand the fluidic stresses generated by this system and other systems of this type, we created a computational fluid dynamics model to simulate the flow during the mechanical loading cycle. Alterations in the frequency or maximal strain magnitude led to a linear increase in the average fluid velocity within the well and a nonlinear increase in the shear stress at the culture surface over the ranges tested (0.5-2.0 Hz and 1-10% maximal strain). For all cases, the applied shear stresses were relatively low and on the order of millipascal with a dynamic waveform having a primary and secondary peak in the shear stress over a single mechanical strain cycle. These findings should be considered when interpreting experimental results using these devices, particularly in the case when the cell type used is sensitive to low magnitude, oscillatory shear stresses.
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Greiner AM, Biela SA, Chen H, Spatz JP, Kemkemer R. Temporal responses of human endothelial and smooth muscle cells exposed to uniaxial cyclic tensile strain. Exp Biol Med (Maywood) 2015; 240:1298-309. [PMID: 25687334 DOI: 10.1177/1535370215570191] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2014] [Accepted: 12/05/2014] [Indexed: 01/23/2023] Open
Abstract
The physiology of vascular cells depends on stimulating mechanical forces caused by pulsatile flow. Thus, mechano-transduction processes and responses of primary human endothelial cells (ECs) and smooth muscle cells (SMCs) have been studied to reveal cell-type specific differences which may contribute to vascular tissue integrity. Here, we investigate the dynamic reorientation response of ECs and SMCs cultured on elastic membranes over a range of stretch frequencies from 0.01 to 1 Hz. ECs and SMCs show different cell shape adaptation responses (reorientation) dependent on the frequency. ECs reveal a specific threshold frequency (0.01 Hz) below which no responses is detectable while the threshold frequency for SMCs could not be determined and is speculated to be above 1 Hz. Interestingly, the reorganization of the actin cytoskeleton and focal adhesions system, as well as changes in the focal adhesion area, can be observed for both cell types and is dependent on the frequency. RhoA and Rac1 activities are increased for ECs but not for SMCs upon application of a uniaxial cyclic tensile strain. Analysis of membrane protrusions revealed that the spatial protrusion activity of ECs and SMCs is independent of the application of a uniaxial cyclic tensile strain of 1 Hz while the total number of protrusions is increased for ECs only. Our study indicates differences in the reorientation response and the reaction times of the two cell types in dependence of the stretching frequency, with matching data for actin cytoskeleton, focal adhesion realignment, RhoA/Rac1 activities, and membrane protrusion activity. These are promising results which may allow cell-type specific activation of vascular cells by frequency-selective mechanical stretching. This specific activation of different vascular cell types might be helpful in improving strategies in regenerative medicine.
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Affiliation(s)
- Alexandra M Greiner
- Department of Cell- and Neurobiology, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
| | - Sarah A Biela
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany
| | - Hao Chen
- Department of Cell- and Neurobiology, Karlsruhe Institute of Technology (KIT), 76131 Karlsruhe, Germany
| | - Joachim P Spatz
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany Department of Biophysical Chemistry, University of Heidelberg, 69120 Heidelberg, Germany
| | - Ralf Kemkemer
- Department of New Materials and Biosystems, Max Planck Institute for Intelligent Systems, 70569 Stuttgart, Germany Department of Applied Chemistry, Reutlingen University, 72762 Reutlingen, Germany
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20
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Differential expressions of the lysyl oxidase family and matrix metalloproteinases-1, 2, 3 in posterior cruciate ligament fibroblasts after being co-cultured with synovial cells. INTERNATIONAL ORTHOPAEDICS 2014; 39:183-91. [DOI: 10.1007/s00264-014-2573-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 10/16/2014] [Indexed: 10/24/2022]
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21
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Israeli-Rosenberg S, Chen C, Li R, Deussen DN, Niesman IR, Okada H, Patel HH, Roth DM, Ross RS. Caveolin modulates integrin function and mechanical activation in the cardiomyocyte. FASEB J 2014; 29:374-84. [PMID: 25366344 DOI: 10.1096/fj.13-243139] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022]
Abstract
β1 integrins (β1) transduce mechanical signals in many cells, including cardiac myocytes (CM). Given their close localization, as well as their role in mechanotransduction and signaling, we hypothesized that caveolin (Cav) proteins might regulate integrins in the CM. β1 localization, complex formation, activation state, and signaling were analyzed using wild-type, Cav3 knockout, and Cav3 CM-specific transgenic heart and myocyte samples. Studies were performed under basal and mechanically loaded conditions. We found that: (1) β1 and Cav3 colocalize in CM and coimmunoprecipitate from CM protein lysates; (2) β1 is detected in a subset of caveolae; (3) loss of Cav3 caused reduction of β1D integrin isoform and active β1 integrin from the buoyant domains in the heart; (4) increased expression of myocyte Cav3 correlates with increased active β1 integrin in adult CM; (5) in vivo pressure overload of the wild-type heart results in increased activated integrin in buoyant membrane domains along with increased association between active integrin and Cav3; and (6) Cav3-deficient myocytes have perturbed basal and stretch mediated signaling responses. Thus, Cav3 protein can modify integrin function and mechanotransduction in the CM and intact heart.
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Affiliation(s)
- Sharon Israeli-Rosenberg
- *Department of Medicine and Department of Anesthesiology, University of California at San Diego, School of Medicine, San Diego, California, USA; U.S. Veterans Administration, San Diego Healthcare System, San Diego, California, USA; and Maastricht University, Maastricht, The Netherlands
| | - Chao Chen
- *Department of Medicine and Department of Anesthesiology, University of California at San Diego, School of Medicine, San Diego, California, USA; U.S. Veterans Administration, San Diego Healthcare System, San Diego, California, USA; and Maastricht University, Maastricht, The Netherlands
| | - Ruixia Li
- *Department of Medicine and Department of Anesthesiology, University of California at San Diego, School of Medicine, San Diego, California, USA; U.S. Veterans Administration, San Diego Healthcare System, San Diego, California, USA; and Maastricht University, Maastricht, The Netherlands
| | - Daniel N Deussen
- *Department of Medicine and Department of Anesthesiology, University of California at San Diego, School of Medicine, San Diego, California, USA; U.S. Veterans Administration, San Diego Healthcare System, San Diego, California, USA; and Maastricht University, Maastricht, The Netherlands
| | - Ingrid R Niesman
- *Department of Medicine and Department of Anesthesiology, University of California at San Diego, School of Medicine, San Diego, California, USA; U.S. Veterans Administration, San Diego Healthcare System, San Diego, California, USA; and Maastricht University, Maastricht, The Netherlands
| | - Hideshi Okada
- *Department of Medicine and Department of Anesthesiology, University of California at San Diego, School of Medicine, San Diego, California, USA; U.S. Veterans Administration, San Diego Healthcare System, San Diego, California, USA; and Maastricht University, Maastricht, The Netherlands
| | - Hemal H Patel
- *Department of Medicine and Department of Anesthesiology, University of California at San Diego, School of Medicine, San Diego, California, USA; U.S. Veterans Administration, San Diego Healthcare System, San Diego, California, USA; and Maastricht University, Maastricht, The Netherlands
| | - David M Roth
- *Department of Medicine and Department of Anesthesiology, University of California at San Diego, School of Medicine, San Diego, California, USA; U.S. Veterans Administration, San Diego Healthcare System, San Diego, California, USA; and Maastricht University, Maastricht, The Netherlands
| | - Robert S Ross
- *Department of Medicine and Department of Anesthesiology, University of California at San Diego, School of Medicine, San Diego, California, USA; U.S. Veterans Administration, San Diego Healthcare System, San Diego, California, USA; and Maastricht University, Maastricht, The Netherlands
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22
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Braakman ST, Pedrigi RM, Read AT, Smith JAE, Stamer WD, Ethier CR, Overby DR. Biomechanical strain as a trigger for pore formation in Schlemm's canal endothelial cells. Exp Eye Res 2014; 127:224-35. [PMID: 25128579 PMCID: PMC4175173 DOI: 10.1016/j.exer.2014.08.003] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 08/01/2014] [Accepted: 08/05/2014] [Indexed: 02/08/2023]
Abstract
The bulk of aqueous humor passing through the conventional outflow pathway must cross the inner wall endothelium of Schlemm's canal (SC), likely through micron-sized transendothelial pores. SC pore density is reduced in glaucoma, possibly contributing to obstructed aqueous humor outflow and elevated intraocular pressure (IOP). Little is known about the mechanisms of pore formation; however, pores are often observed near dome-like cellular outpouchings known as giant vacuoles (GVs) where significant biomechanical strain acts on SC cells. We hypothesize that biomechanical strain triggers pore formation in SC cells. To test this hypothesis, primary human SC cells were isolated from three non-glaucomatous donors (aged 34, 44 and 68), and seeded on collagen-coated elastic membranes held within a membrane stretching device. Membranes were then exposed to 0%, 10% or 20% equibiaxial strain, and the cells were aldehyde-fixed 5 min after the onset of strain. Each membrane contained 3-4 separate monolayers of SC cells as replicates (N = 34 total monolayers), and pores were assessed by scanning electron microscopy in 12 randomly selected regions (∼65,000 μm(2) per monolayer). Pores were identified and counted by four independent masked observers. Pore density increased with strain in all three cell lines (p < 0.010), increasing from 87 ± 36 pores/mm(2) at 0% strain to 342 ± 71 at 10% strain; two of the three cell lines showed no additional increase in pore density beyond 10% strain. Transcellular "I-pores" and paracellular "B-pores" both increased with strain (p < 0.038), however B-pores represented the majority (76%) of pores. Pore diameter, in contrast, appeared unaffected by strain (p = 0.25), having a mean diameter of 0.40 μm for I-pores (N = 79 pores) and 0.67 μm for B-pores (N = 350 pores). Pore formation appears to be a mechanosensitive process that is triggered by biomechanical strain, suggesting that SC cells have the ability to modulate local pore density and filtration characteristics of the inner wall endothelium based on local biomechanical cues. The molecular mechanisms of pore formation and how they become altered in glaucoma may be studied in vitro using stretched SC cells.
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Affiliation(s)
- Sietse T Braakman
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Ryan M Pedrigi
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - A Thomas Read
- Department of Ophthalmology and Vision Sciences, University of Toronto, Canada
| | - James A E Smith
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - W Daniel Stamer
- Department of Ophthalmology, Duke University Medical School, USA
| | - C Ross Ethier
- Department of Bioengineering, Imperial College London, London, United Kingdom; Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, USA
| | - Darryl R Overby
- Department of Bioengineering, Imperial College London, London, United Kingdom.
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23
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Zhang Y, Huang W, Jiang J, Xie J, Xu C, Wang C, Yin L, Yang L, Zhou K, Chen P, Sung KP. Influence of TNF-α and biomechanical stress on matrix metalloproteinases and lysyl oxidases expressions in human knee synovial fibroblasts. Knee Surg Sports Traumatol Arthrosc 2014; 22:1997-2006. [PMID: 23377799 DOI: 10.1007/s00167-013-2425-z] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2012] [Accepted: 01/21/2013] [Indexed: 01/10/2023]
Abstract
PURPOSE It was reported that not only ACL but also the synovium may be the major regulator of matrix metalloproteinases (MMPs) in synovial fluids after ACL injury. In order to further confirm whether synovium is capable of regulating the microenvironment in the process of ACL injury, the complicated microenvironment of joint cavity after ACL injury was mimicked and the combined effects of mechanical injury and inflammatory factor [tumour necrosis factor-α (TNF-α)] on expressions of lysyl oxidases (LOXs) and MMPs in synovial fibroblasts derived from normal human synovium were studied. METHODS Human normal knee joint synovial fibroblasts were stimulated for 1-6 h with mechanical stretch and inflammatory factor (TNF-α). Total RNA was harvested, reverse transcribed and assessed by real-time polymerase chain reaction for the expression of LOXs and MMP-1, 2, 3 messenger RNAs. MMP-2 activity was assayed from the collected culture media samples using zymography. RESULTS Compared to control group, our results showed that 6% physiological stretch increased MMP-2 and LOXs (except LOXL-3), decreased MMP-1 and MMP-3; injurious stretch (12%) decreased LOXs (except LOXL-2)and increased MMP-1, 2 and 3; the combination of injurious stretch and TNF-α decreased LOXs and increased MMP-1, 2 and 3 in synovial fibroblasts in a synergistical manner. CONCLUSION This study demonstrated that combination of mechanical injury and inflammatory factors up-regulated the expressions of MMPs and down-regulated the expressions of LOXs in synovial fibroblasts, eventually alter the balance of tissue healing. Thus, synovium may be involved in regulating the microenvironment of joint cavity. Based on the mechanism, early interventions to inhibit the production of MMPs or promote the production of LOXs in the synovial fibroblasts should be performed to facilitate the healing of tissue.
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Affiliation(s)
- Yanjun Zhang
- "111" Project Laboratory of Biomechanics and Tissue Repair, Bioengineering College, Chongqing University, Chongqing, 400044, China
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24
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Heller Z, Wyatt J, Arnaud A, Wolchok JC. An In Vitro Impact Model for the Study of Central Nervous System Cell Mechanobiology. Cell Mol Bioeng 2014. [DOI: 10.1007/s12195-014-0347-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022] Open
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25
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Nayak AR, Pandit R. Spiral-wave dynamics in ionically realistic mathematical models for human ventricular tissue: the effects of periodic deformation. Front Physiol 2014; 5:207. [PMID: 24959148 PMCID: PMC4050366 DOI: 10.3389/fphys.2014.00207] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2013] [Accepted: 05/14/2014] [Indexed: 11/20/2022] Open
Abstract
We carry out an extensive numerical study of the dynamics of spiral waves of electrical activation, in the presence of periodic deformation (PD) in two-dimensional simulation domains, in the biophysically realistic mathematical models of human ventricular tissue due to (a) ten-Tusscher and Panfilov (the TP06 model) and (b) ten-Tusscher, Noble, Noble, and Panfilov (the TNNP04 model). We first consider simulations in cable-type domains, in which we calculate the conduction velocity θ and the wavelength λ of a plane wave; we show that PD leads to a periodic, spatial modulation of θ and a temporally periodic modulation of λ; both these modulations depend on the amplitude and frequency of the PD. We then examine three types of initial conditions for both TP06 and TNNP04 models and show that the imposition of PD leads to a rich variety of spatiotemporal patterns in the transmembrane potential including states with a single rotating spiral (RS) wave, a spiral-turbulence (ST) state with a single meandering spiral, an ST state with multiple broken spirals, and a state SA in which all spirals are absorbed at the boundaries of our simulation domain. We find, for both TP06 and TNNP04 models, that spiral-wave dynamics depends sensitively on the amplitude and frequency of PD and the initial condition. We examine how these different types of spiral-wave states can be eliminated in the presence of PD by the application of low-amplitude pulses by square- and rectangular-mesh suppression techniques. We suggest specific experiments that can test the results of our simulations.
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Affiliation(s)
- Alok R. Nayak
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of ScienceBangalore, India
- Robert Bosch Centre for Cyber Physical Systems, Indian Institute of ScienceBangalore, India
| | - Rahul Pandit
- Centre for Condensed Matter Theory, Department of Physics, Indian Institute of ScienceBangalore, India
- Jawaharlal Nehru Centre for Advanced Scientific ResearchBangalore, India
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26
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Abdul Rahim NA, Pelet S, Mofrad MRK, So PTC, Kamm RD. Quantifying intracellular protein binding thermodynamics during mechanotransduction based on FRET spectroscopy. Methods 2014; 66:208-21. [PMID: 24184188 PMCID: PMC4094350 DOI: 10.1016/j.ymeth.2013.10.007] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2013] [Revised: 09/24/2013] [Accepted: 10/12/2013] [Indexed: 11/29/2022] Open
Abstract
Mechanical force modulates myriad cellular functions including migration, alignment, proliferation, and gene transcription. Mechanotransduction, the transmission of mechanical forces and its translation into biochemical signals, may be mediated by force induced protein conformation changes, subsequently modulating protein signaling. For the paxillin and focal adhesion kinase interaction, we demonstrate that force-induced changes in protein complex conformation, dissociation constant, and binding Gibbs free energy can be quantified by lifetime-resolved fluorescence energy transfer microscopy combined with intensity imaging calibrated by fluorescence correlation spectroscopy. Comparison with in vitro data shows that this interaction is allosteric in vivo. Further, spatially resolved imaging and inhibitor assays show that this protein interaction and its mechano-sensitivity are equal in the cytosol and in the focal adhesions complexes indicating that the mechano-sensitivity of this interaction must be mediated by soluble factors but not based on protein tyrosine phosphorylation.
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Affiliation(s)
- Nur Aida Abdul Rahim
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, United states
| | - Serge Pelet
- Department of Biological Engineering, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, United States; Department of Fundamental Microbiology, University of Lausanne, Biophore Building, Room 2406, CH-1015 Lausanne, Switzerland
| | - Mohammad R K Mofrad
- Department of Bioengineering, University of California Berkeley, 306 Stanley Hall MC #1762, Berkeley, CA 94720-1762, United States
| | - Peter T C So
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, United states; Department of Biological Engineering, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, United States; Laser Biomedical Research Center, A NIH NIBIB Research Resource, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, United States.
| | - Roger D Kamm
- Department of Mechanical Engineering, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, United states; Department of Biological Engineering, Massachusetts Institute of Technology, 77 Mass Ave., Cambridge, MA 02139, United States
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27
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Design and construction of an equibiaxial cell stretching system that is improved for biochemical analysis. PLoS One 2014; 9:e90665. [PMID: 24626190 PMCID: PMC3953117 DOI: 10.1371/journal.pone.0090665] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2013] [Accepted: 02/04/2014] [Indexed: 11/19/2022] Open
Abstract
We describe the design and validation of an equibiaxial stretching device in which cells are confined to regions of homogeneous strain. Using this device, we seek to overcome a significant limitation of existing equibiaxial stretching devices, in which strains are not homogeneous over the entire region of cell culture. We cast PDMS in a mold to produce a membrane with a cylindrical wall incorporated in the center, which was used to confine cell monolayers to the central membrane region subjected to homogeneous equibiaxial strain. We demonstrated that the presence of the wall to hold the culture medium did not affect strain homogeneity over the majority of the culture surface and also showed that cells adhered well onto the PDMS membranes. We used our device in cyclic strain experiments and demonstrated strain-dependent changes in extracellular signal-regulated kinase (ERK) and tyrosine phosphorylation upon cell stretching. Furthermore, we examined cell responses to very small magnitudes of strain ranging from 1% to 6% and were able to observe a graduated increase in ERK phosphorylation in response to these strains. Collectively, we were able to study cellular biochemical response with a high degree of accuracy and sensitivity to fine changes in substrate strain. Because we have designed our device along the lines of existing equibiaxial stretching technologies, we believe that our innovations can be incorporated into existing systems. This device would provide a useful addition to the set of tools applied for in vitro studies of cell mechanobiology.
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28
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Lyon RC, Mezzano V, Wright AT, Pfeiffer E, Chuang J, Banares K, Castaneda A, Ouyang K, Cui L, Contu R, Gu Y, Evans SM, Omens JH, Peterson KL, McCulloch AD, Sheikh F. Connexin defects underlie arrhythmogenic right ventricular cardiomyopathy in a novel mouse model. Hum Mol Genet 2014; 23:1134-50. [PMID: 24108106 PMCID: PMC3919010 DOI: 10.1093/hmg/ddt508] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2013] [Revised: 09/06/2013] [Accepted: 10/04/2013] [Indexed: 12/27/2022] Open
Abstract
Arrhythmogenic right ventricular cardiomyopathy (ARVC) termed a 'disease of the desmosome' is an inherited cardiomyopathy that recently underwent reclassification owing to the identification of left-dominant and biventricular disease forms. Homozygous loss-of-function mutations in the desmosomal component, desmoplakin, are found in patients exhibiting a biventricular form of ARVC; however, no models recapitulate the postnatal hallmarks of the disease as seen in these patients. To gain insights into the homozygous loss-of-function effects of desmoplakin in the heart, we generated cardiomyocyte-specific desmoplakin-deficient mice (DSP-cKO) using ventricular myosin light chain-2-Cre mice. Homozygous DSP-cKO mice are viable but display early ultrastructural defects in desmosomal integrity leading to a cardiomyopathy reminiscent of a biventricular form of ARVC, which includes cell death and fibro-fatty replacement within the ventricle leading to biventricular dysfunction, failure and premature death. DSP-cKO mice also exhibited ventricular arrhythmias that are exacerbated with exercise and catecholamine stimulation. Furthermore, DSP-cKO hearts exhibited right ventricular conduction defects associated with loss of connexin 40 expression and electrical wavefront propagation defects associated with loss of connexin 43 expression. Dose-dependent assessment of the effects of loss of desmoplakin in neonatal ventricular cardiomyocytes revealed primary loss of connexin 43 levels, phosphorylation and function independent of the molecular dissociation of the mechanical junction complex and fibro-fatty manifestation associated with ARVC, suggesting a role for desmoplakin as a primary stabilizer of connexin integrity. In summary, we provide evidence for a novel mouse model, which is reminiscent of the postnatal onset of ARVC while highlighting mechanisms underlying a biventricular form of human ARVC.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Li Cui
- Department of Skaggs School of Pharmacy, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | | | | | - Sylvia M. Evans
- Department of Skaggs School of Pharmacy, University of California-San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
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Lau JJ, Wang RM, Black LD. Development of an arbitrary waveform membrane stretcher for dynamic cell culture. Ann Biomed Eng 2014; 42:1062-73. [PMID: 24473700 DOI: 10.1007/s10439-014-0976-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2013] [Accepted: 01/10/2014] [Indexed: 11/29/2022]
Abstract
In this paper, a novel cell stretcher design that mimics the real-time stretch of the heart wall is introduced. By culturing cells under stretched conditions that mimics the mechanical aspects of the native cardiac environment, better understanding on the role of biomechanical signaling on cell development can be achieved. The device utilizes a moving magnet linear actuator controlled through pulse-width modulated power combined with an automated closed loop feedback system for accurate generation of a designated mechanical stretch profile. The system's capability to stretch a cell culture membrane and accuracy of the designated frequency and waveform production for cyclic stretching were evaluated. Temperature and degradation assessments as well as a scalable design demonstrated the system's cell culture application for long term, in vitro studies.
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Affiliation(s)
- Jason J Lau
- Department of Biomedical Engineering, Tufts University, 4 Colby Street, Medford, MA, 02155, USA
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30
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Shao Y, Tan X, Novitski R, Muqaddam M, List P, Williamson L, Fu J, Liu AP. Uniaxial cell stretching device for live-cell imaging of mechanosensitive cellular functions. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2013; 84:114304. [PMID: 24289415 PMCID: PMC3862604 DOI: 10.1063/1.4832977] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Abstract
External mechanical stretch plays an important role in regulating cellular behaviors through intracellular mechanosensitive and mechanotransductive machineries such as the F-actin cytoskeleton (CSK) structures and focal adhesions (FAs) anchoring the F-actin CSK to the extracellular environment. Studying the mechanoresponsive behaviors of the F-actin CSK and FAs in response to cell stretch has great importance for further understanding mechanotransduction and mechanobiology. In this work, we developed a novel cell stretching device combining dynamic directional cell stretch with in situ subcellular live-cell imaging. Using a cam and follower mechanism and applying a standard mathematical model for cam design, we generated different dynamic stretch outputs. By examining stretch-mediated FA dynamics under step-function static stretch and the realignment of cell morphology and the F-actin CSK under cyclic stretch, we demonstrated successful applications of our cell stretching device for mechanobiology studies where external stretch plays an important role in regulating subcellular molecular dynamics and cellular phenotypes.
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Affiliation(s)
- Yue Shao
- Integrated Biosystems and Biomechanics Laboratory, University of Michigan, Ann Arbor, Michigan 48109, USA
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31
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Regulation of tissue fibrosis by the biomechanical environment. BIOMED RESEARCH INTERNATIONAL 2013; 2013:101979. [PMID: 23781495 PMCID: PMC3679815 DOI: 10.1155/2013/101979] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 05/10/2013] [Indexed: 12/21/2022]
Abstract
The biomechanical environment plays a fundamental role in embryonic development, tissue maintenance, and pathogenesis. Mechanical forces play particularly important roles in the regulation of connective tissues including not only bone and cartilage but also the interstitial tissues of most organs. In vivo studies have correlated changes in mechanical load to modulation of the extracellular matrix and have indicated that increased mechanical force contributes to the enhanced expression and deposition of extracellular matrix components or fibrosis. Pathological fibrosis contributes to dysfunction of many organ systems. A variety of in vitro models have been utilized to evaluate the effects of mechanical force on extracellular matrix-producing cells. In general, application of mechanical stretch, fluid flow, and compression results in increased expression of extracellular matrix components. More recent studies have indicated that tissue rigidity also provides profibrotic signals to cells. The mechanisms whereby cells detect mechanical signals and transduce them into biochemical responses have received considerable attention. Cell surface receptors for extracellular matrix components and intracellular signaling pathways are instrumental in the mechanotransduction process. Understanding how mechanical signals are transmitted from the microenvironment will identify novel therapeutic targets for fibrosis and other pathological conditions.
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32
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Olesen CG, Pennisi CP, de Zee M, Zachar V, Rasmussen J. Elliptical posts allow for detailed control of non-equibiaxial straining of cell cultures. J Tissue Viability 2013; 22:52-6. [DOI: 10.1016/j.jtv.2013.02.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2012] [Revised: 02/26/2013] [Accepted: 02/27/2013] [Indexed: 01/19/2023]
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33
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Leopold E, Gefen A. Changes in permeability of the plasma membrane of myoblasts to fluorescent dyes with different molecular masses under sustained uniaxial stretching. Med Eng Phys 2013; 35:601-7. [DOI: 10.1016/j.medengphy.2012.07.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2012] [Revised: 06/28/2012] [Accepted: 07/12/2012] [Indexed: 01/27/2023]
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34
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Xie J, Wang C, Huang DY, Zhang Y, Xu J, Kolesnikov SS, Sung K, Zhao H. TGF-beta1 induces the different expressions of lysyl oxidases and matrix metalloproteinases in anterior cruciate ligament and medial collateral ligament fibroblasts after mechanical injury. J Biomech 2013; 46:890-8. [DOI: 10.1016/j.jbiomech.2012.12.019] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2012] [Revised: 12/06/2012] [Accepted: 12/21/2012] [Indexed: 11/25/2022]
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35
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Guo Y, Zeng QC, Zhang CQ, Zhang XZ, Li RX, Wu JM, Guan J, Liu L, Zhang XC, Li JY, Wan ZM. Extracellular matrix of mechanically stretched cardiac fibroblasts improves viability and metabolic activity of ventricular cells. Int J Med Sci 2013; 10:1837-45. [PMID: 24324360 PMCID: PMC3856374 DOI: 10.7150/ijms.6786] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 08/26/2013] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND In heart, the extracellular matrix (ECM), produced by cardiac fibroblasts, is a potent regulator of heart's function and growth, and provides a supportive scaffold for heart cells in vitro and in vivo. Cardiac fibroblasts are subjected to mechanical loading all the time in vivo. Therefore, the influences of mechanical loading on formation and bioactivity of cardiac fibroblasts ECM should be investigated. METHODS Rat cardiac fibroblasts were cultured on silicone elastic membranes and stimulated with mechanical cyclic stretch. After removing the cells, the ECMs coated on the membranes were prepared, some ECMs were treated with heparinase II (GAG-lyase), then the collagen, glycosaminoglycan (GAG) and ECM proteins were assayed. Isolated neonatal rat ventricular cells were seeded on ECM-coated membranes, the viability and lactate dehydrogenase (LDH) activity of the cells after 1-7 days of culture was assayed. In addition, the ATPase activity and related protein level, glucose consumption ratio and lactic acid production ratio of the ventricular cells were analyzed by spectrophotometric methods and Western blot. RESULTS The cyclic stretch increased collagen and GAG levels of the ECMs, and elevated protein levels of collagen I and fibronectin. Compared with the ECMs produced by unstretched cardiac fibroblasts, the ECMs of mechanically stretched fibroblasts improved viability and LDH activity, elevated the Na⁺/K⁺-ATPase activity, sarco(endo)plasmic reticulum Ca²⁺-ATPase (SERCA) activity and SERCA 2a protein level, glucose consumption ratio and lactic acid production ratio of ventricular cells seeded on them. The treatment with heparinase II reduced GAG levels of these ECMs, and lowered these metabolism-related indices of ventricular cells cultured on the ECMs. CONCLUSIONS Mechanical stretch promotes ECM formation of cardiac fibroblasts in vitro, the ECM of mechanically stretched cardiac fibroblasts improves metabolic activity of ventricular cells cultured in vitro, and the GAG of the ECMs is involved in regulating metabolic activity of ventricular cells.
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Affiliation(s)
- Yong Guo
- 1. Lab of Biomaterial, Tianjin Institute of Medical Equipment, Academy of Military Medical Science, Tianjin, China
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36
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Hirt MN, Sörensen NA, Bartholdt LM, Boeddinghaus J, Schaaf S, Eder A, Vollert I, Stöhr A, Schulze T, Witten A, Stoll M, Hansen A, Eschenhagen T. Increased afterload induces pathological cardiac hypertrophy: a new in vitro model. Basic Res Cardiol 2012; 107:307. [PMID: 23099820 PMCID: PMC3505530 DOI: 10.1007/s00395-012-0307-z] [Citation(s) in RCA: 105] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2012] [Revised: 10/16/2012] [Accepted: 10/17/2012] [Indexed: 12/22/2022]
Abstract
Increased afterload results in 'pathological' cardiac hypertrophy, the most important risk factor for the development of heart failure. Current in vitro models fall short in deciphering the mechanisms of hypertrophy induced by afterload enhancement. The aim of this study was to develop an experimental model that allows investigating the impact of afterload enhancement (AE) on work-performing heart muscles in vitro. Fibrin-based engineered heart tissue (EHT) was cast between two hollow elastic silicone posts in a 24-well cell culture format. After 2 weeks, the posts were reinforced with metal braces, which markedly increased afterload of the spontaneously beating EHTs. Serum-free, triiodothyronine-, and hydrocortisone-supplemented medium conditions were established to prevent undefined serum effects. Control EHTs were handled identically without reinforcement. Endothelin-1 (ET-1)- or phenylephrine (PE)-stimulated EHTs served as positive control for hypertrophy. Cardiomyocytes in EHTs enlarged by 28.4 % under AE and to a similar extent by ET-1- or PE-stimulation (40.6 or 23.6 %), as determined by dystrophin staining. Cardiomyocyte hypertrophy was accompanied by activation of the fetal gene program, increased glucose consumption, and increased mRNA levels and extracellular deposition of collagen-1. Importantly, afterload-enhanced EHTs exhibited reduced contractile force and impaired diastolic relaxation directly after release of the metal braces. These deleterious effects of afterload enhancement were preventable by endothelin-A, but not endothelin-B receptor blockade. Sustained afterload enhancement of EHTs alone is sufficient to induce pathological cardiac remodeling with reduced contractile function and increased glucose consumption. The model will be useful to investigate novel therapeutic approaches in a simple and fast manner.
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Affiliation(s)
- Marc N Hirt
- Department of Experimental Pharmacology and Toxicology, University Medical Center Hamburg-Eppendorf and DZHK, Germany
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37
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Ramírez-Sánchez I, Mendoza-Lorenzo P, Zentella-Dehesa A, Méndez-Bolaina E, Lara-Padilla E, Ceballos-Reyes G, Canto P, Palma-Flores C, Coral-Vázquez RM. Caveolae and non-caveolae lipid raft microdomains of human umbilical vein endothelial cells contain utrophin-associated protein complexes. Biochimie 2012; 94:1884-90. [DOI: 10.1016/j.biochi.2012.05.001] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Accepted: 05/01/2012] [Indexed: 12/16/2022]
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38
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Kang MN, Yoon HH, Seo YK, Park JK. Human umbilical cord-derived mesenchymal stem cells differentiate into ligament-like cells with mechanical stimulation in various media. Tissue Eng Regen Med 2012. [DOI: 10.1007/s13770-012-0333-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
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39
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Mechanical strain controls endothelial patterning during angiogenic sprouting. Cell Mol Bioeng 2012; 5:463-473. [PMID: 24015155 DOI: 10.1007/s12195-012-0242-y] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Cyclic strain is known to affect endothelial cell phenotype, but its effects on neovascular pattern formation remain poorly understood. To examine how cyclic strain affects angiogenesis, we designed a stretchable, polydimethylsiloxane (PDMS)-based multi-well system that supports a 3D cell culture model of angiogenesis, consisting of endothelial cells coated onto microcarrier beads embedded in a fibrin gel with a supporting monolayer of smooth muscle cells atop the gel. Calibration of the integrated system showed a linear relationship between applied strain and strain within the fibrin gel. Capillaries formed in unstrained conditions grew radially outward, while 3D constructs subjected to 10% cyclic strain at 0.7 Hz sprouted in a direction parallel to the applied strain. Removal of the tissue from the strain stimulus eliminated directional sprouting. To better understand this directional biasing, the strain field surrounding a microcarrier bead was modeled computationally, showing local strain anisotropy surrounding a microcarrier. Confocal reflection microscopy revealed only modest fiber alignment in regions of the gel close to microcarriers, with no evidence of alignment further away. Together, these data showed that externally applied cyclic strain can spatially pattern capillaries in a 3D culture, and suggests a means to control pattern formation in engineered tissues.
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40
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Milner JS, Grol MW, Beaucage KL, Dixon SJ, Holdsworth DW. Finite-element modeling of viscoelastic cells during high-frequency cyclic strain. J Funct Biomater 2012; 3:209-24. [PMID: 24956525 PMCID: PMC4031015 DOI: 10.3390/jfb3010209] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2012] [Revised: 03/06/2012] [Accepted: 03/13/2012] [Indexed: 12/20/2022] Open
Abstract
Mechanotransduction refers to the mechanisms by which cells sense and respond to local loads and forces. The process of mechanotransduction plays an important role both in maintaining tissue viability and in remodeling to repair damage; moreover, it may be involved in the initiation and progression of diseases such as osteoarthritis and osteoporosis. An understanding of the mechanisms by which cells respond to surrounding tissue matrices or artificial biomaterials is crucial in regenerative medicine and in influencing cellular differentiation. Recent studies have shown that some cells may be most sensitive to low-amplitude, high-frequency (i.e., 1-100 Hz) mechanical stimulation. Advances in finite-element modeling have made it possible to simulate high-frequency mechanical loading of cells. We have developed a viscoelastic finite-element model of an osteoblastic cell (including cytoskeletal actin stress fibers), attached to an elastomeric membrane undergoing cyclic isotropic radial strain with a peak value of 1,000 µstrain. The results indicate that cells experience significant stress and strain amplification when undergoing high-frequency strain, with peak values of cytoplasmic strain five times higher at 45 Hz than at 1 Hz, and peak Von Mises stress in the nucleus increased by a factor of two. Focal stress and strain amplification in cells undergoing high-frequency mechanical stimulation may play an important role in mechanotransduction.
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Affiliation(s)
- Jaques S Milner
- Imaging Research Laboratory, Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON N6A 5K8, Canada.
| | - Matthew W Grol
- Department of Anatomy and Cell Biology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada.
| | - Kim L Beaucage
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada.
| | - S Jeffrey Dixon
- Department of Physiology and Pharmacology, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON N6A 5C1, Canada.
| | - David W Holdsworth
- Imaging Research Laboratory, Robarts Research Institute, Schulich School of Medicine & Dentistry, The University of Western Ontario, London, ON N6A 5K8, Canada.
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41
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Hecht E, Knittel P, Felder E, Dietl P, Mizaikoff B, Kranz C. Combining atomic force-fluorescence microscopy with a stretching device for analyzing mechanotransduction processes in living cells. Analyst 2012; 137:5208-14. [DOI: 10.1039/c2an36001b] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
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42
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Levy A, Enzer S, Shoham N, Zaretsky U, Gefen A. Large, but not small sustained tensile strains stimulate adipogenesis in culture. Ann Biomed Eng 2011; 40:1052-60. [PMID: 22203192 DOI: 10.1007/s10439-011-0496-x] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2011] [Accepted: 12/17/2011] [Indexed: 12/13/2022]
Abstract
Understanding the mechanoresponsiveness of adipocytes and the characteristics of the mechanical stimuli that regulate adipogenesis is critically important in establishing knowledge in regard to the long-term effects of a sedentary lifestyle (or immobility in extreme medical conditions) as well as concerning obesity and related diseases. In this study we subjected 3T3-L1 preadipocytes cultured on elastic substrata to different levels of static equiaxial tensile strains within the physiological range, up to substrate tensile strain (STS) of 12%, while inducing differentiation in the cultures. Based on prior work which revealed that adipogenesis is accelerated in cultures subjected to STS of 12% by activating the mitogen-activated protein kinase kinase signaling pathway, we were specifically interested in identifying the STS levels which trigger this process. We hence monitored the production and accumulation of lipid droplets (LDs) using a non-destructive, image-processing-based method that we have previously developed, for a period of 4 weeks. The experimental data demonstrated accelerated adipogenesis in the cultures subjected to STS levels of 6%, 9%, and 12% with respect to cultures subjected to STS of 3% and (non-stretched) control cultures. This accelerated adipogenic response to the large sustained STS manifested in significantly larger numbers and greater sizes of LDs in the cultures that were stretched to large STS levels (p < 0.05), starting at approximately day 14 following induction of differentiation. Hence, indeed, there appears to be a certain tensile strain threshold, or domain-which is found within the physiological range-above which the responsiveness of adipocytes to sustained static stretching increases and is manifested in accelerated adipogenesis.
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Affiliation(s)
- Ayelet Levy
- Department of Biomedical Engineering, Tel Aviv University, 69978 Tel Aviv, Israel
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43
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Richardson WJ, Metz RP, Moreno MR, Wilson E, Moore JE. A Device to Study the Effects of Stretch Gradients on Cell Behavior. J Biomech Eng 2011; 133:101008. [DOI: 10.1115/1.4005251] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Mechanical forces are key regulators of cell function with varying loads capable of modulating behaviors such as alignment, migration, phenotype modulation, and others. Historically, cell-stretching experiments have employed mechanically simple environments (e.g., uniform uniaxial or equibiaxial stretches). However, stretch distributions in vivo can be highly non-uniform, particularly in cases of disease or subsequent to interventional treatments. Herein, we present a cell-stretching device capable of subjecting cells to controllable gradients in biaxial stretch via radial deformation of circular elastomeric membranes. By including either a defect or a rigid fixation at the center of the membrane, various gradients are generated. Capabilities of the device were quantified by tracking marked positions of the membrane while applying various loads, and experimental feasibility was assessed by conducting preliminary experiments with 3T3 fibroblasts and 10T1/2 cells subjected to 24 h of cyclic stretch. Quantitative real-time PCR was used to measure changes in mRNA expression of a profile of genes representing the major smooth muscle phenotypes. Genes associated with the contractile state were both upregulated (e.g., calponin) and downregulated (e.g., α-2-actin), and genes associated with the synthetic state were likewise both upregulated (e.g., SKI-like oncogene) and downregulated (e.g., collagen III). In addition, cells aligned with an orientation perpendicular to the maximal stretch direction. We have developed an in vitro cell culture device that can produce non-uniform stretch environments similar to in vivo mechanics. Cells stretched with this device showed alignment and altered mRNA expression indicative of phenotype modulation. Understanding these processes as they relate to in vivo pathologies could enable a more accurately targeted treatment to heal or inhibit disease, either through implantable device design or pharmaceutical approaches.
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Affiliation(s)
- William J. Richardson
- Department of Biomedical Engineering, Texas A&M University, 337 Zachry Engineering Center, 3120 TAMU, College Station, TX 77843
| | - Richard P. Metz
- Department of Systems Biology and Translational Medicine, Texas A&M Health Science Center, 336 Reynolds Medical Building, College Station, TX 77843
| | - Michael R. Moreno
- Department of Biomedical Engineering, Texas A&M University, 337 Zachry Engineering Center, 3120 TAMU, College Station, TX 77843
| | - Emily Wilson
- Department of Systems Biology and Translational Medicine, Texas A&M Health Science Center, 336 Reynolds Medical Building, College Station, TX 77843
| | - James E. Moore
- Department of Biomedical Engineering, Texas A&M University, 337 Zachry Engineering Center, 3120 TAMU, College Station, TX 77843
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44
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Shoham N, Gottlieb R, Sharabani-Yosef O, Zaretsky U, Benayahu D, Gefen A. Static mechanical stretching accelerates lipid production in 3T3-L1 adipocytes by activating the MEK signaling pathway. Am J Physiol Cell Physiol 2011; 302:C429-41. [PMID: 22012328 DOI: 10.1152/ajpcell.00167.2011] [Citation(s) in RCA: 69] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Understanding mechanotransduction in adipocytes is important for research of obesity and related diseases. We cultured 3T3-L1 preadipocytes on elastic substrata and applied static tensile strains of 12% to the substrata while inducing differentiation. Using an image processing method, we monitored lipid production for a period of 3-4 wk. The ratio of %-lipid area per field of view (FOV) in the stretched over nonstretched cultures was significantly greater than unity (P < 0.05), reaching ∼1.8 on average starting from experimental day ∼10. The superior coverage of the FOV by lipids in the stretched cultures was due to significantly greater sizes of lipid droplets (LDs) with respect to nonstretched cultures, starting from experimental day ∼10 (P < 0.05), and due to significantly more LDs per cell between days ∼10 and ∼17 (P < 0.05). The statically stretched cells also differentiated significantly faster than the nonstretched cells within the first ∼10 days (P < 0.05). Adding peroxisome proliferator-activated receptor-γ (PPARγ) antagonist did not change these trends, as the %-lipid area per FOV in the stretched cultures that received this treatment was still significantly greater than in the nonstretched cultures without the PPARγ antagonist (14.44 ± 1.96% vs. 10.21 ± 3%; P < 0.05). Hence, the accelerated adipogenesis in the stretched cultures was not mediated through PPARγ. Nonetheless, inhibiting the MEK/MAPK signaling pathway reduced the extent of adipogenesis in the stretched cultures (13.53 ± 5.63%), bringing it to the baseline level of the nonstretched cultures without the MEK inhibitor (10.21 ± 3.07%). Our results hence demonstrate that differentiation of adipocytes can be enhanced by sustained stretching, which activates the MEK signaling pathway.
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Affiliation(s)
- Naama Shoham
- Department of Biomedical Engineering, Faculty of Engineering, Tel Aviv University, Israel
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45
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Magou GC, Guo Y, Choudhury M, Chen L, Hususan N, Masotti S, Pfister BJ. Engineering a high throughput axon injury system. J Neurotrauma 2011; 28:2203-18. [PMID: 21787172 DOI: 10.1089/neu.2010.1596] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Several key biological mechanisms of traumatic injury to axons have been elucidated using in vitro stretch injury models. These models, however, are based on the experimentation of single cultures keeping productivity slow. Indeed, low yield has hindered important and well-founded investigations requiring high throughput methods such as proteomic analyses. To meet this need, we engineered a multi-well high throughput injury device to accelerate and accommodate the next generation of traumatic brain injury research. This modular system stretch injures neuronal cultures in either a 24-well culture plate format or 6 individual wells simultaneously. Custom software control allows the user to accurately program the pressure pulse parameters to achieve the desired substrate deformation and injury parameters. Analysis of the pressure waveforms showed that peak pressure was linearly related to input pressure and valve open times and that the 6- and 24-well modules displayed rise times, peak pressures, and decays with extremely small standard deviations. Data also confirmed that the pressure pulse was distributed evenly throughout the pressure chambers and therefore to each injury well. Importantly, the relationship between substrate deformation and applied pressure was consistent among the multiple wells and displayed a predictable linear behavior in each module. These data confirm that this multi-well system performs as well as currently used stretch injury devices and can undertake high throughput studies that are needed across the field of neurotrauma research.
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Affiliation(s)
- George C Magou
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, New Jersey 07102, USA
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46
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Slomka N, Gefen A. Relationship Between Strain Levels and Permeability of the Plasma Membrane in Statically Stretched Myoblasts. Ann Biomed Eng 2011; 40:606-18. [DOI: 10.1007/s10439-011-0423-1] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 09/27/2011] [Indexed: 01/21/2023]
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47
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Zhao L, Sang C, Yang C, Zhuang F. Effects of stress fiber contractility on uniaxial stretch guiding mitosis orientation and stress fiber alignment. J Biomech 2011; 44:2388-94. [PMID: 21767844 DOI: 10.1016/j.jbiomech.2011.06.033] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2010] [Revised: 06/29/2011] [Accepted: 06/29/2011] [Indexed: 11/28/2022]
Abstract
It has been documented that mitosis orientation (MO) is guided by stress fibers (SFs), which are perpendicular to exogenous cyclic uniaxial stretch. However, the effect of mechanical forces on MO and the mechanism of stretch-induced SFs reorientation are not well elucidated to date. In the present study, we used murine 3T3 fibroblasts as a model, to investigate the effects of uniaxial stretch on SFO and MO utilizing custom-made stretch device. We found that cyclic uniaxial stretch induced both SFs and mitosis directions orienting perpendicularly to the stretch direction. The F-actin and myosin II blockages, which resulted in disoriented SFs and mitosis directions under uniaxial stretch, suggested a high correlation between SFO and MO. Y27632 (10 μM), ML7 (50 μM, or 75 μM), and blebbistatin (50 μM, or 75 μM) treatments resulted in SFO parallel to the principle stretch direction. Upon stimulating and inhibiting the phosphorylation of myosin light chain (p-MLC), we observed a monotonic proportion of SFO to the level of p-MLC. These results suggested that the level of cell contraction is crucial to the response of SFs, either perpendicular or parallel, to the external stretch. Showing the possible role of cell contractility in tuning SFO under external stretch, our experimental data are valuable to understand the predominant factor controlling SFO response to exogenous uniaxial stretch, and thus helpful for improving mechanical models.
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Affiliation(s)
- Lei Zhao
- School of Biological Science and Medical Engineering, Beihang University, Beijing 100191, China
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Wang Y, Tang Z, Xue R, Singh GK, Shi K, Lv Y, Yang L. Combined effects of TNF-α, IL-1β, and HIF-1α on MMP-2 production in ACL fibroblasts under mechanical stretch: an in vitro study. J Orthop Res 2011; 29:1008-14. [PMID: 21344498 DOI: 10.1002/jor.21349] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/13/2010] [Accepted: 12/09/2010] [Indexed: 02/04/2023]
Abstract
The dynamics between inflammatory factors, mechanical stress, and healing factors, in an intra-articular joint, are very complex after injury. Injury to intra-articular tissue [anterior cruciate ligament (ACL), synovium] results in hypoxia, accumulation of various pro-inflammatory factors, cytokines, and metalloproteases. Although the presence of increased amounts of matrix-metalloproteinases (MMP) in the joint fluid after knee injury is considered the key factor for ACL poor healing ability; however, the exact role of collective participants of the joint fluid on MMP-2 activity and production has not been fully studied yet. To investigate the combined effects of mechanical injury, inflammation and hypoxia induced factor-1α (HIF-1α) on induction of MMP-2; we mimicked the microenvironment of joint cavity after ACL injury. The results show that TNF-α and IL-1β elevate the activity of MMP-2 in a dose- and time-dependent manner. In addition, mechanical stretch further enhances the MMP-2 protein levels with TNF-α, IL-1β, and their mixture. CoCl(2) -induced HIF-1α (100 and 500 µM) also increases the levels and activity of MMP-2. Mechanical stretch has a strong additional effect on MMP-2 production with HIF-1α. Our results conclude that mechanical injury, HIF-1α and inflammatory factors collectively induce increased MMP-2 production in ACL fibroblasts, which was inhibited by NF-κB pathway inhibitor (Bay-11-7082).
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Affiliation(s)
- Yequan Wang
- Key Laboratory of Biorheological Science and Technology (Chongqing University), Ministry of Education, Bioengineering College, Chongqing University, Chongqing 400044, PR China
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Abstract
The differentiation of adipose-derived stem cells (ASCs) into functional smooth muscle cells has received limited investigation. Various methodologies for both in vitro and in vivo differentiation is described. In vitro differentiation is obtained by either chemical or mechanical stimulation, and is determined by expression of smooth muscle cell markers. In vivo differentiation studies include animal models of cardiovascular disease and one study with urinary bladder reconstruction. The ease of obtaining an abundant number of ASCs render this cell population useful for potential vascular therapies that require autologous smooth muscle cells.
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Affiliation(s)
- Kacey G Marra
- Division of Plastic Surgery, Department of Surgery, McGowan Institute for Regenerative Medicine, Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
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Hishiya A, Kitazawa T, Takayama S. BAG3 and Hsc70 interact with actin capping protein CapZ to maintain myofibrillar integrity under mechanical stress. Circ Res 2010; 107:1220-31. [PMID: 20884878 DOI: 10.1161/circresaha.110.225649] [Citation(s) in RCA: 113] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
RATIONALE A homozygous disruption or genetic mutation of the bag3 gene, a member of the Bcl-2-associated athanogene (BAG) family proteins, causes cardiomyopathy and myofibrillar myopathy that is characterized by myofibril and Z-disc disruption. However, the detailed disease mechanism is not yet fully understood. OBJECTIVE bag3(-/-) mice exhibit differences in the extent of muscle degeneration between muscle groups with muscles experiencing the most usage degenerating at an accelerated rate. Usage-dependent muscle degeneration suggests a role for BAG3 in supporting cytoskeletal connections between the Z-disc and myofibrils under mechanical stress. The mechanism by which myofibrillar structure is maintained under mechanical stress remains unclear. The purpose of the study is to clarify the detailed molecular mechanism of BAG3-mediated muscle maintenance under mechanical stress. METHODS AND RESULTS To address the question of whether bag3 gene knockdown induces myofibrillar disorganization caused by mechanical stress, in vitro mechanical stretch experiments using rat neonatal cardiomyocytes and a short hairpin RNA-mediated gene knockdown system of the bag3 gene were performed. As expected, mechanical stretch rapidly disrupts myofibril structures in bag3 knockdown cardiomyocytes. BAG3 regulates the structural stability of F-actin through the actin capping protein, CapZβ1, by promoting association between Hsc70 and CapZβ1. BAG3 facilitates the distribution of CapZβ1 to the proper location, and dysfunction of BAG3 induces CapZ ubiquitin-proteasome-mediated degradation. Inhibition of CapZβ1 function by overexpressing CapZβ2 increased myofibril vulnerability and fragmentation under mechanical stress. On the other hand, overexpression of CapZβ1 inhibits myofibrillar disruption in bag3 knockdown cells under mechanical stress. As a result, heart muscle isolated from bag3(-/-) mice exhibited myofibrillar degeneration and lost contractile activity after caffeine contraction. CONCLUSIONS These results suggest novel roles for BAG3 and Hsc70 in stabilizing myofibril structure and inhibiting myofibrillar degeneration in response to mechanical stress. These proteins are possible targets for further research to identify therapies for myofibrillar myopathy or other degenerative diseases.
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Affiliation(s)
- Akinori Hishiya
- Boston Biomedical Research Institute, Watertown, MA 02472, USA
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