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Robertson SYT, Roberts JS, Deng SX. Regulation of Limbal Epithelial Stem Cells: Importance of the Niche. Int J Mol Sci 2021; 22:11975. [PMID: 34769405 PMCID: PMC8584795 DOI: 10.3390/ijms222111975] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/12/2021] [Revised: 10/29/2021] [Accepted: 11/03/2021] [Indexed: 12/11/2022] Open
Abstract
Limbal epithelial stem/progenitor cells (LSCs) reside in a niche that contains finely tuned balances of various signaling pathways including Wnt, Notch, BMP, Shh, YAP, and TGFβ. The activation or inhibition of these pathways is frequently dependent on the interactions of LSCs with various niche cell types and extracellular substrates. In addition to receiving molecular signals from growth factors, cytokines, and other soluble molecules, LSCs also respond to their surrounding physical structure via mechanotransduction, interaction with the ECM, and interactions with other cell types. Damage to LSCs or their niche leads to limbal stem cell deficiency (LSCD). The field of LSCD treatment would greatly benefit from an understanding of the molecular regulation of LSCs in vitro and in vivo. This review synthesizes current literature around the niche factors and signaling pathways that influence LSC function. Future development of LSCD therapies should consider all these niche factors to achieve improved long-term restoration of the LSC population.
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Affiliation(s)
| | | | - Sophie X. Deng
- Jules Stein Eye Institute, University of California, Los Angeles, CA 94143, USA; (S.Y.T.R.); (J.S.R.)
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2
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Patel M, Min JH, Hong MH, Lee HJ, Kang S, Yi S, Koh WG. Culture of neural stem cells on conductive and microgrooved polymeric scaffolds fabricated via electrospun fiber-template lithography. Biomed Mater 2020; 15:045007. [DOI: 10.1088/1748-605x/ab763b] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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3
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Xiong S, Gao H, Qin L, Jia YG, Ren L. Engineering topography: Effects on corneal cell behavior and integration into corneal tissue engineering. Bioact Mater 2019; 4:293-302. [PMID: 31709312 PMCID: PMC6829100 DOI: 10.1016/j.bioactmat.2019.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 08/23/2019] [Accepted: 10/07/2019] [Indexed: 12/13/2022] Open
Abstract
Cell-material interactions are important to tissue engineering. Inspired by the natural topographic structures on the extracellular matrix, a growing number of studies have integrated engineering topography into investigations of cell behavior on biomaterials. Engineering topography has a significant influence on cell behaviors. These cell-topography interactions play an important role in regenerative medicine and tissue engineering. Similarly, cell-topography interactions are important to corneal reconstruction and regeneration. In this review, we primarily summarized the effects of topographic cues on the behaviors of corneal cells, including cell morphology, adhesion, migration, and proliferation. Furthermore, the integration of engineering surface topography into corneal tissue engineering was also discussed.
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Affiliation(s)
- Sijia Xiong
- School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510641, China
- National Engineering Research Centre for Tissue Restoration and Reconstruction, Guangzhou, 510006, China
| | - HuiChang Gao
- School of Medicine, South China University of Technology, Guangzhou, 510006, China
| | - Lanfeng Qin
- National Engineering Research Centre for Tissue Restoration and Reconstruction, Guangzhou, 510006, China
- School of Biology and Biological Engineering, South China University of Technology, Guangzhou, 510006, China
| | - Yong-Guang Jia
- School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510641, China
- National Engineering Research Centre for Tissue Restoration and Reconstruction, Guangzhou, 510006, China
| | - Li Ren
- School of Materials Science and Engineering, South China University of Technology, Guangzhou, 510641, China
- National Engineering Research Centre for Tissue Restoration and Reconstruction, Guangzhou, 510006, China
- Sino-Singapore International Joint Research Institute, Guangzhou, 510555, China
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4
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Ermis M, Antmen E, Hasirci V. Micro and Nanofabrication methods to control cell-substrate interactions and cell behavior: A review from the tissue engineering perspective. Bioact Mater 2018; 3:355-369. [PMID: 29988483 PMCID: PMC6026330 DOI: 10.1016/j.bioactmat.2018.05.005] [Citation(s) in RCA: 161] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2017] [Revised: 05/09/2018] [Accepted: 05/10/2018] [Indexed: 02/07/2023] Open
Abstract
Cell-substrate interactions play a crucial role in the design of better biomaterials and integration of implants with the tissues. Adhesion is the binding process of the cells to the substrate through interactions between the surface molecules of the cell membrane and the substrate. There are several factors that affect cell adhesion including substrate surface chemistry, topography, and stiffness. These factors physically and chemically guide and influence the adhesion strength, spreading, shape and fate of the cell. Recently, technological advances enabled us to precisely engineer the geometry and chemistry of substrate surfaces enabling the control of the interaction cells with the substrate. Some of the most commonly used surface engineering methods for eliciting the desired cellular responses on biomaterials are photolithography, electron beam lithography, microcontact printing, and microfluidics. These methods allow production of nano- and micron level substrate features that can control cell adhesion, migration, differentiation, shape of the cells and the nuclei as well as measurement of the forces involved in such activities. This review aims to summarize the current techniques and associate these techniques with cellular responses in order to emphasize the effect of chemistry, dimensions, density and design of surface patterns on cell-substrate interactions. We conclude with future projections in the field of cell-substrate interactions in the hope of providing an outlook for the future studies.
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Affiliation(s)
- Menekse Ermis
- BIOMATEN, Middle East Technical University (METU) Center of Excellence in Biomaterials and Tissue Engineering, Ankara, Turkey
- METU, Department of Biomedical Engineering, Ankara, Turkey
| | - Ezgi Antmen
- BIOMATEN, Middle East Technical University (METU) Center of Excellence in Biomaterials and Tissue Engineering, Ankara, Turkey
- METU, Department of Biotechnology, Ankara, Turkey
| | - Vasif Hasirci
- BIOMATEN, Middle East Technical University (METU) Center of Excellence in Biomaterials and Tissue Engineering, Ankara, Turkey
- METU, Department of Biomedical Engineering, Ankara, Turkey
- METU, Department of Biotechnology, Ankara, Turkey
- METU, Department of Biological Sciences, Ankara, Turkey
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5
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Molladavoodi S, Robichaud M, Wulff D, Gorbet M. Corneal epithelial cells exposed to shear stress show altered cytoskeleton and migratory behaviour. PLoS One 2017; 12:e0178981. [PMID: 28662184 PMCID: PMC5491001 DOI: 10.1371/journal.pone.0178981] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2016] [Accepted: 05/22/2017] [Indexed: 12/22/2022] Open
Abstract
Cells that form the corneal epithelium, the outermost layer of the cornea, are exposed to shear stress through blinking during waking hours. In this in vitro study, the effect of fluid shear stress on human corneal epithelial cells (HCECs) was investigated. Following exposure to shear stresses of 4 and 8 dyn/cm2, HCECs showed cytoskeletal rearrangement with more prominent, organized and elongated filamentous actin. Cytoskeletal changes were time-dependent, and were most significant after 24 hours of shear stress. Higher rates of migration and proliferation, as evaluated by a scratch assay, were also observed following 24 hours of low shear stress exposure (4 dyn/cm2). This result contrasted the poor migration observed in samples scratched before shear exposure, indicating that shear-induced cytoskeletal changes played a key role in improved wound healing and must therefore precede any damage to the cell layer. HCEC cytoskeletal changes were accompanied by an upregulation in integrin β1 and downregulation of ICAM-1. These results demonstrate that HCECs respond favourably to flow-induced shear stress, impacting their proliferation and migration properties as well as phenotype.
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Affiliation(s)
- Sara Molladavoodi
- Department of System Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Matthew Robichaud
- Department of System Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - David Wulff
- Department of Chemical Engineering, University of Waterloo, Waterloo, Ontario, Canada
| | - Maud Gorbet
- Department of System Design Engineering, University of Waterloo, Waterloo, Ontario, Canada
- * E-mail:
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6
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Heyart B, Weidt A, Wisotzki EI, Zink M, Mayr SG. Micropatterning of reagent-free, high energy crosslinked gelatin hydrogels for bioapplications. J Biomed Mater Res B Appl Biomater 2017; 106:320-330. [PMID: 28140524 DOI: 10.1002/jbm.b.33849] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2016] [Revised: 11/21/2016] [Accepted: 12/26/2016] [Indexed: 12/28/2022]
Abstract
Hydrogels are crosslinked polymeric gels of great interest in the field of tissue engineering, particularly as biocompatible cell or drug carriers. Reagent-free electron irradiated gelatin is simple to manufacture, inexpensive and biocompatible. Here, the potential to micropattern gelatin hydrogel surfaces during electron irradiation crosslinking was demonstrated as a promising microfabrication technique to produce thermally stable structures on highly relevant length scales for bioapplications. In the present work, grooves of 3.75 to 170 µm width and several hundred nanometers depth were transferred onto gelatin hydrogels during electron irradiation and characterized by 3D confocal microscopy after exposure to ambient and physiological conditions. The survival and influence of these microstructures on cellular growth was further characterized using NIH 3T3 fibroblasts. Topographical modifications produced surface structures on which the cultured fibroblasts attached and responded by adapting their morphologies. This developed technique allows for simple and effective structuring of gelatin and opens up new possibilities for irradiation crosslinked hydrogels in biomedical applications in which cell attachment and contact guidance are favored. © 2017 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 106B: 320-330, 2018.
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Affiliation(s)
- Benedikt Heyart
- Leibniz Institute for Surface Modification (IOM), Permoserstr. 15, 04318, Leipzig, Germany
| | - Astrid Weidt
- Soft Matter Physics Division, Institute for Experimental Physics 1, University of Leipzig, Linnéstr. 5, 04103, Leipzig, Germany
| | - Emilia I Wisotzki
- Leibniz Institute for Surface Modification (IOM), Permoserstr. 15, 04318, Leipzig, Germany
| | - Mareike Zink
- Soft Matter Physics Division, Institute for Experimental Physics 1, University of Leipzig, Linnéstr. 5, 04103, Leipzig, Germany
| | - Stefan G Mayr
- Leibniz Institute for Surface Modification (IOM), Permoserstr. 15, 04318, Leipzig, Germany.,Division of Surface Physics, Department of Physics and Earth Sciences, University of Leipzig, Leipzig, Germany
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7
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A high throughput approach for analysis of cell nuclear deformability at single cell level. Sci Rep 2016; 6:36917. [PMID: 27841297 PMCID: PMC5107983 DOI: 10.1038/srep36917] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2016] [Accepted: 10/12/2016] [Indexed: 01/14/2023] Open
Abstract
Various physiological and pathological processes, such as cell differentiation, migration, attachment, and metastasis are highly dependent on nuclear elasticity. Nuclear morphology directly reflects the elasticity of the nucleus. We propose that quantification of changes in nuclear morphology on surfaces with defined topography will enable us to assess nuclear elasticity and deformability. Here, we used soft lithography techniques to produce 3 dimensional (3-D) cell culture substrates decorated with micron sized pillar structures of variable aspect ratios and dimensions to induce changes in cellular and nuclear morphology. We developed a high content image analysis algorithm to quantify changes in nuclear morphology at the single-cell level in response to physical cues from the 3-D culture substrate. We present that nuclear stiffness can be used as a physical parameter to evaluate cancer cells based on their lineage and in comparison to non-cancerous cells originating from the same tissue type. This methodology can be exploited for systematic study of mechanical characteristics of large cell populations complementing conventional tools such as atomic force microscopy and nanoindentation.
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8
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Zhang X, Aoyama T, Yasuda T, Oike M, Ito A, Tajino J, Nagai M, Fujioka R, Iijima H, Yamaguchi S, Kakinuma N, Kuroki H. Effect of microfabricated microgroove-surface devices on the morphology of mesenchymal stem cells. Biomed Microdevices 2016; 17:116. [PMID: 26573821 DOI: 10.1007/s10544-015-0016-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
The surface of a material that is in contact with cells is known to affect cell morphology and function. To develop an appropriate surface for tendon engineering, we used zigzag microgroove surfaces, which are similar to the tenocyte microenvironment. The purpose of this study was to investigate the effect of microgroove surfaces with different ridge angles (RAs), ridge lengths (RLs), ridge widths (RWs), and groove widths (GWs) on human bone marrow-derived mesenchymal stem cell (MSC) shape. Dishes with microgroove surfaces were fabricated using cyclic olefin polymer by injection-compression molding. The other parameters were fixed, and effects of different RAs (180 - 30 °), RLs (5 - 500 μm), RWs (5 - 500 μm), and GWs (5 - 500 μm) were examined. Changes in the zigzag shape of the cell due to different RAs, RLs, RWs, and GWs were observed by optical microscopy and scanning electron microscopy. Cytoskeletal changes were investigated using Phalloidin immunofluorescence staining. As observed by optical microscopy, MSCs changed to a zigzag shape in response to microgroove surfaces with different ridge and groove properties. . As observed by scanning electron microscopy, the cell shape changed at turns in the microgroove surface. Phalloidin immunofluorescence staining indicated that F-actin, not only in cell filopodia but also inside the cell body, changed orientation to conform to the microgrooves. In conclusion, the use of zigzag microgroove surfaces microfabricated by injection-compression molding demonstrated the property of MSCs to alter their shapes to fit the surface.
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Affiliation(s)
- Xiangkai Zhang
- Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Tomoki Aoyama
- Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan.
| | - Takashi Yasuda
- Precision Machinery Department, SEIKOH GIKEN Co., Ltd., Chiba, Japan
| | - Makoto Oike
- Precision Machinery Department, SEIKOH GIKEN Co., Ltd., Chiba, Japan
| | - Akira Ito
- Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Junichi Tajino
- Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Momoko Nagai
- Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Rune Fujioka
- Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Hirotaka Iijima
- Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Shoki Yamaguchi
- Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
| | - Norihiro Kakinuma
- Precision Machinery Department, SEIKOH GIKEN Co., Ltd., Chiba, Japan
| | - Hiroshi Kuroki
- Human Health Sciences, Graduate School of Medicine, Kyoto University, 53 kawahara-cho, Shogoin, Sakyo-ku, Kyoto, 606-8507, Japan
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9
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Suffoletto K, Ye N, Meng F, Verma D, Hua SZ. Intracellular forces during guided cell growth on micropatterns using FRET measurement. J Biomech 2015; 48:627-635. [PMID: 25596631 PMCID: PMC4330124 DOI: 10.1016/j.jbiomech.2014.12.051] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2014] [Revised: 12/19/2014] [Accepted: 12/26/2014] [Indexed: 01/16/2023]
Abstract
Interaction of cells with extracellular matrix (ECM) regulates cell shape, differentiation and polarity. This effect has been widely observed in cells grown on substrates with various patterned features, stiffness and surface chemistry. It has been postulated that mechanical confinement of cells by the substrate causes a redistribution of tension in cytoskeletal proteins resulting in cytoskeletal reorganization through force sensitive pathways. However, the mechanisms for force transduction during reorganization remain unclear. In this study, using FRET based force sensors we have measured tension in an actin cross-linking protein, α-actinin, and followed reorganization of actin cytoskeleton in real time in HEK cells grown on patterned substrates. We show that the patterned substrates cause a redistribution of tension in α-actinin that coincides with cytoskeleton reorganization. Higher tension was observed in portions of cells where they form bridges across inhibited regions of the patterned substrates; the attachment to the substrate is found to release tension. Real time measurements of α-actinin tension and F-actin arrangement show that an increase in tension coincides with formation of F-actin bundles at the cell periphery during cell-spreading across inhibited regions, suggesting that mechanical forces stimulate cytoskeleton enhancement. Rho-ROCK inhibitor (Y27632) causes reduction in actinin tension followed by retraction of bridged regions. Our results demonstrate that changes in cell shape and expansion over patterned surfaces is a force sensitive process that requires actomyosin contractile force involving Rho-ROCK pathway.
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Affiliation(s)
- Kevin Suffoletto
- Department of Mechanical and Aerospace Engineering, SUNY-Buffalo, Buffalo, New York 14260, United States
| | - Nannan Ye
- Department of Mechanical and Aerospace Engineering, SUNY-Buffalo, Buffalo, New York 14260, United States
| | - Fanjie Meng
- Department of Physiology and Biophysics, SUNY-Buffalo, Buffalo, New York 14260, United States
| | - Deepika Verma
- Department of Mechanical and Aerospace Engineering, SUNY-Buffalo, Buffalo, New York 14260, United States
| | - Susan Z Hua
- Department of Mechanical and Aerospace Engineering, SUNY-Buffalo, Buffalo, New York 14260, United States; Department of Physiology and Biophysics, SUNY-Buffalo, Buffalo, New York 14260, United States.
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10
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De Luca AC, Zink M, Weidt A, Mayr SG, Markaki AE. Effect of microgrooved surface topography on osteoblast maturation and protein adsorption. J Biomed Mater Res A 2015; 103:2689-700. [PMID: 25630566 DOI: 10.1002/jbm.a.35407] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2014] [Revised: 01/16/2015] [Accepted: 01/20/2015] [Indexed: 12/12/2022]
Abstract
Microgrooved surfaces have been used extensively to influence cell contact guidance. Guiding cell growth, extracellular matrix deposition, and mineralization is important for bone implant longevity. In this study, we investigated the osteoblast response to microgrooved metallic surfaces in serum-supplemented medium. Groove spacing was comparable with the spread osteoblast size. Focal adhesions were observed to confine to the intervening ridge/groove boundaries. Osteoblasts bridged over the grooves and were unable to conform to the concave shape of the underlying grooves. Microgrooved surfaces induced higher osteoblast proliferation and metabolic activity after 14 days in osteogenic medium compared with as-received surfaces, resulting in higher mineralization and alignment of cell-secreted collagen after 28 days. To establish whether preferential cell attachment at the ridge/groove boundaries was influenced by the adhesion proteins contained in the serum-supplemented media, fluorescently labeled fibronectin was adsorbed onto the microgrooved substrates at low concentrations, mimicking the concentrations found in blood serum. Fibronectin was found to selectively adsorb onto the ridge/groove boundaries, the osteoblast focal adhesion sites, suggesting that protein adsorption may have influenced the cell attachment pattern.
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Affiliation(s)
- Alba C De Luca
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ, United Kingdom
| | - Mareike Zink
- Faculty of Physics and Earth Sciences, Institute for Experimental Physics I, Soft Matter Physics Division, University of Leipzig, Linnéstraße 5, 04103, Leipzig, Germany
| | - Astrid Weidt
- Faculty of Physics and Earth Sciences, Institute for Experimental Physics I, Soft Matter Physics Division, University of Leipzig, Linnéstraße 5, 04103, Leipzig, Germany
| | - Stefan G Mayr
- Leibniz Institute for Surface Modification (IOM), Translational Centre for Regenerative Medicine and Faculty of Physics and Earth Sciences, University of Leipzig, Permoserstraße 15, 04318, Leipzig, Germany
| | - Athina E Markaki
- Department of Engineering, University of Cambridge, Trumpington Street, Cambridge, CB2 1PZ, United Kingdom
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11
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Gao J, Raghunathan VK, Reid B, Wei D, Diaz RC, Russell P, Murphy CJ, Zhao M. Biomimetic stochastic topography and electric fields synergistically enhance directional migration of corneal epithelial cells in a MMP-3-dependent manner. Acta Biomater 2015; 12:102-112. [PMID: 25311684 DOI: 10.1016/j.actbio.2014.10.007] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 10/02/2014] [Accepted: 10/04/2014] [Indexed: 01/14/2023]
Abstract
Directed migration of corneal epithelial cells (CECs) is critical for maintenance of corneal homeostasis as well as wound healing. Soluble cytoactive factors and the intrinsic chemical attributes of the underlying extracellular matrix (ECM) participate in stimulating and directing migration. The central importance of the intrinsic biophysical attributes of the microenvironment of the cell in modulating an array of fundamental epithelial behaviors including migration has been widely documented. Among the best measures of these attributes are the intrinsic topography and stiffness of the ECM and electric fields (EFs). How cells integrate these multiple simultaneous inputs is not well understood. Here, we present a method that combines the use of (i) topographically patterned substrates (mean pore diameter 800nm) possessing features that approximate those found in the native corneal basement membrane; and (ii) EFs (0-150mVmm(-1)) mimicking those at corneal epithelial wounds that the cells experience in vivo. We found that topographic cues and EFs synergistically regulated directional migration of human CECs and that this was associated with upregulation of matrix metalloproteinase-3 (MMP3). MMP3 expression and activity were significantly elevated with 150mVmm(-1) applied-EF while MMP2/9 remained unaltered. MMP3 expression was elevated in cells cultured on patterned surfaces against planar surfaces. The highest single-cell migration rate was observed with 150mVmm(-1) applied EF on patterned and planar surfaces. When cultured as a confluent sheet, EFs induced collective cell migration on stochastically patterned surfaces compared with dissociated single-cell migration on planar surfaces. These results suggest significant interaction of biophysical cues in regulating cell behaviors and will help define design parameters for corneal prosthetics and help to better understand corneal wound healing.
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12
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Raghunathan VK, Dreier B, Morgan JT, Tuyen BC, Rose BW, Reilly CM, Russell P, Murphy CJ. Involvement of YAP, TAZ and HSP90 in contact guidance and intercellular junction formation in corneal epithelial cells. PLoS One 2014; 9:e109811. [PMID: 25290150 PMCID: PMC4188597 DOI: 10.1371/journal.pone.0109811] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Accepted: 09/03/2014] [Indexed: 11/20/2022] Open
Abstract
The extracellular environment possesses a rich milieu of biophysical and biochemical signaling cues that are simultaneously integrated by cells and influence cellular phenotype. Yes-associated protein (YAP) and transcriptional co-activator with PDZ-binding motif (WWTR1; TAZ), two important signaling molecules of the Hippo pathway, have been recently implicated as nuclear relays of cytoskeletal changes mediated by substratum rigidity and topography. These proteins intersect with other important intracellular signaling pathways (e.g. Wnt and TGFβ). In the cornea, epithelial cells adhere to the stroma through a 3-dimensional topography-rich basement membrane, with features in the nano-submicron size-scale that are capable of profoundly modulating a wide range of fundamental cell behaviors. The influences of substratum-topography, YAP/TAZ knockdown, and HSP90 inhibition on cell morphology, YAP/TAZ localization, and the expression of TGFβ2 and CTGF, were investigated. The results demonstrate (a) that knockdown of TAZ enhances contact guidance in a YAP dependent manner, (b) that CTGF is predominantly regulated by YAP and not TAZ, and (c) that TGFβ2 is regulated by both YAP and TAZ in these cells. Additionally, inhibition of HSP90 resulted in nuclear localization and subsequent transcriptional-activation of YAP, formation of cell-cell junctions and co-localization of E-cadherin and β-catenin at adherens junctions. Results presented in this study reflect the complexities underlying the molecular relationships between the cytoskeleton, growth factors, heat shock proteins, and co-activators of transcription that impact mechanotransduction. The data reveal the importance of YAP/TAZ on the cell behaviors, and gene and protein expression.
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Affiliation(s)
- Vijay Krishna Raghunathan
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America
| | - Britta Dreier
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America
| | - Joshua T. Morgan
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America
| | - Binh C. Tuyen
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America
| | - Brad W. Rose
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America
| | - Christopher M. Reilly
- Department of Pathology, Microbiology & Immunology, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America
| | - Paul Russell
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America
| | - Christopher J. Murphy
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, CA, United States of America
- Department of Ophthalmology & Vision Science, School of Medicine, University of California Davis, Davis, CA, United States of America
- * E-mail:
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13
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Soleas JP, Waddell TK, McGuigan AP. Topographically grooved gel inserts for aligning epithelial cells during air-liquid-interface culture. Biomater Sci 2014. [PMID: 26214196 DOI: 10.1039/c4bm00237g] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Epithelial tissues are a critical component of all tubular organs. Engineering artificial epithelium requires an understanding of the polarization of epithelia: both apicobasal and in a planar fashion. Air liquid interface (ALI) culture is typically used to generate apicobasal polarized airway epithelium in vitro; however, this approach does not provide any signalling cues to induce morphological planar polarization of the generated epithelial layer. Here we describe a microgrooved gelatin hydrogel insert that can induce alignment of confluent epithelial cell sheets under ALI conditions to induce both apicobasal and morphologically planar polarized epithelium. Microgrooves are imprinted into the surface of the gelatin insert using elastomeric stamps moulded from a diffraction grating film and gels are stabilized by crosslinking with glutaraldehyde. We show that microgrooved gelatin inserts produce alignment of 3T3 fibroblasts and a number of epithelial cell lines (ARPE-19, BEAS2B and IMCD3 cells). Furthermore, we show that BEAS2B apicobasally polarize and form a similar density of cilia on both gelatin inserts and standard transwell filters used for ALI culture but that as apicobasal polarization progresses cell alignment on the grooves is lost. Our method provides a simple strategy that can easily be adopted by labs without microfabrication expertise for manipulating epithelial organization in transwell culture and studying the interplay of various polarization forces.
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Affiliation(s)
- John P Soleas
- Institute of Medical Science, University of Toronto, 200 College St., Toronto, ON M5S 3E5, Canada
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14
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Guiding the behaviors of human umbilical vein endothelial cells with patterned silk fibroin films. Colloids Surf B Biointerfaces 2014; 122:79-84. [PMID: 25016547 DOI: 10.1016/j.colsurfb.2014.06.049] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2014] [Revised: 05/31/2014] [Accepted: 06/23/2014] [Indexed: 11/23/2022]
Abstract
Silk fibroin is an ideal blood vessel substitute due to its advantageous qualities including variable size, good suture retention, low thrombogenicity, non-toxicity, non-immunogenicity, biocompatibility, and controllable biodegradation. In this study, silk fibroin films with a variety of surface patterns (e.g. square wells, round wells plus square pillars, square pillars, and gratings) were prepared for in vitro characterization of human umbilical vein endothelial cell's (HUVEC) response. The affects of biomimetic length-scale topographic cues on the cell orientation/elongation, proliferation, and cell-substrate interactions have been investigated. The density of cells is significantly decreased in response to the grating patterns (70±3nm depth, 600±8nm pitch) and the square pillars (333±42nm gap). Most notably, we observed the contact guidance response of filopodia of cells cultured on the surface of round wells plus square pillars. Overall, our data demonstrates that the patterned silk fibroin films have an impact on the behaviors of human umbilical vein endothelial cells.
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Raghunathan V, McKee C, Cheung W, Naik R, Nealey PF, Russell P, Murphy CJ. Influence of extracellular matrix proteins and substratum topography on corneal epithelial cell alignment and migration. Tissue Eng Part A 2014; 19:1713-22. [PMID: 23488816 DOI: 10.1089/ten.tea.2012.0584] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The basement membrane (BM) of the corneal epithelium presents biophysical cues in the form of topography and compliance that can impact the phenotype and behaviors of cells and their nuclei through modulation of cytoskeletal dynamics. In addition, it is also well known that the intrinsic biochemical attributes of BMs can modulate cell behaviors. In this study, the influence of the combination of exogenous coating of extracellular matrix proteins (ECM) (fibronectin-collagen [FNC]) with substratum topography was investigated on cytoskeletal architecture as well as alignment and migration of immortalized corneal epithelial cells. In the absence of FNC coating, a significantly greater percentage of cells aligned parallel with the long axis of the underlying anisotropically ordered topographic features; however, their ability to migrate was impaired. Additionally, changes in the surface area, elongation, and orientation of cytoskeletal elements were differentially influenced by the presence or absence of FNC. These results suggest that the effects of topographic cues on cells are modulated by the presence of surface-associated ECM proteins. These findings have relevance to experiments using cell cultureware with biomimetic biophysical attributes as well as the integration of biophysical cues in tissue-engineering strategies and the development of improved prosthetics.
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Affiliation(s)
- Vijaykrishna Raghunathan
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
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Paz AC, Soleas J, Poon JC, Trieu D, Waddell TK, McGuigan AP. Challenges and Opportunities for Tissue-Engineering Polarized Epithelium. TISSUE ENGINEERING PART B-REVIEWS 2014; 20:56-72. [DOI: 10.1089/ten.teb.2013.0144] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Ana C. Paz
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
| | - John Soleas
- Latner Thoracic Surgery Research Laboratories, McEwen Centre for Regenerative Medicine, Toronto General Hospital, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - James C.H. Poon
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Latner Thoracic Surgery Research Laboratories, McEwen Centre for Regenerative Medicine, Toronto General Hospital, Toronto, ON, Canada
| | - Dennis Trieu
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
- Latner Thoracic Surgery Research Laboratories, McEwen Centre for Regenerative Medicine, Toronto General Hospital, Toronto, ON, Canada
| | - Thomas K. Waddell
- Latner Thoracic Surgery Research Laboratories, McEwen Centre for Regenerative Medicine, Toronto General Hospital, Toronto, ON, Canada
- Institute of Medical Science, University of Toronto, Toronto, ON, Canada
| | - Alison P. McGuigan
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Toronto, ON, Canada
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON, Canada
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McHugh KJ, Saint-Geniez M, Tao SL. Topographical control of ocular cell types for tissue engineering. J Biomed Mater Res B Appl Biomater 2013; 101:1571-84. [PMID: 23744715 PMCID: PMC4090092 DOI: 10.1002/jbm.b.32968] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/24/2012] [Revised: 03/19/2013] [Accepted: 04/21/2013] [Indexed: 02/06/2023]
Abstract
Visual impairment affects over 285 million people worldwide and has a major impact on an individual's quality of life. Tissue engineering has the potential to increase the quality of life for many of these patients by preventing vision loss or restoring vision using cell-based therapies. However, these strategies will require an understanding of the microenvironmental factors that influence cell behavior. The eye is a well-organized organ whose structural complexity is essential for proper function. Interactions between ocular cells and their highly ordered extracellular matrix are necessary for maintaining key tissue properties including corneal transparency and retinal lamination. Therefore, it is not surprising that culturing these cells in vitro on traditional flat substrates result in irregular morphology. Instead, topographically patterned biomaterials better mimic native extracellular matrix and have been shown to elicit in vivo-like morphology and gene expression which is essential for tissue engineering. Herein we review multiple methods for producing well-controlled topography and discuss optimal biomaterial scaffold design for cells of the cornea, retina, and lens.
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Affiliation(s)
- Kevin J. McHugh
- The Charles Stark Draper Laboratory, Cambridge, MA
- Schepens Eye Research Institute, Boston, MA
- Department of Biomedical Engineering, Boston University, Boston, MA
| | - Magali Saint-Geniez
- Schepens Eye Research Institute, Boston, MA
- Department of Ophthalmology, Harvard Medical School, Boston, MA
| | - Sarah L. Tao
- The Charles Stark Draper Laboratory, Cambridge, MA
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Dreier B, Gasiorowski JZ, Morgan JT, Nealey PF, Russell P, Murphy CJ. Early responses of vascular endothelial cells to topographic cues. Am J Physiol Cell Physiol 2013; 305:C290-8. [PMID: 23703527 DOI: 10.1152/ajpcell.00264.2012] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Vascular endothelial cells in vivo are exposed to multiple biophysical cues provided by the basement membrane, a specialized extracellular matrix through which vascular endothelial cells are attached to the underlying stroma. The importance of biophysical cues has been widely reported, but the signaling pathways that mediate cellular recognition and response to these cues remain poorly understood. Anisotropic topographically patterned substrates with nano- through microscale feature dimensions were fabricated to investigate cellular responses to topographic cues. The present study focuses on early events following exposure of human umbilical vein endothelial cells (HUVECs) to these patterned substrates. In serum-free medium and on substrates without protein coating, HUVECs oriented parallel to the long axis of underlying ridges in as little as 30 min. Immunocytochemistry showed clear differences in the localization of the focal adhesion proteins Src, p130Cas, and focal adhesion kinase (FAK) in HUVECs cultured on topographically patterned surfaces and on planar surfaces, suggesting involvement of these proteins in mediating the response to topographic features. Knockdown experiments demonstrated that FAK was not necessary for HUVEC alignment in response to topographic cues, although FAK knockdown did modulate HUVEC migration. These data identify key events early in the cellular response to biophysical stimuli.
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Affiliation(s)
- Britta Dreier
- Department of Surgical and Radiological Sciences, School of Veterinary Medicine, University of California Davis, Davis, California, USA
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Lawrence BD, Pan Z, Liu A, Kaplan DL, Rosenblatt MI. Human corneal limbal epithelial cell response to varying silk film geometric topography in vitro. Acta Biomater 2012; 8:3732-43. [PMID: 22705042 DOI: 10.1016/j.actbio.2012.06.009] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2012] [Revised: 04/26/2012] [Accepted: 06/07/2012] [Indexed: 12/15/2022]
Abstract
Silk fibroin films are a promising class of biomaterials that have a number of advantages for use in ophthalmic applications due to their transparent nature, mechanical properties and minimal inflammatory response upon implantation. Freestanding silk films with parallel line and concentric ring topographies were generated for in vitro characterization of human corneal limbal epithelial (HCLE) cell response upon differing geometric patterned surfaces. Results indicated that silk film topography significantly affected initial HCLE culture substrate attachment, cellular alignment, cell-to-cell contact formation, actin cytoskeleton alignment and focal adhesion (FA) localization. Most notably, parallel line patterned surfaces displayed a 36-54% increase on average in initial cell attachment, which corresponded to a more than 2-fold increase in FA localization when compared to other silk film surfaces and controls. In addition, distinct localization of FA formation was observed along the edges for all patterned silk film topographies. In conclusion, silk film feature topography appears to help direct corneal epithelial cell response and cytoskeleton development, especially with regard to FA distribution, in vitro.
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Affiliation(s)
- Brian D Lawrence
- Department of Biomedical Engineering, Cornell University, Ithaca, NY, USA
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Nikkhah M, Edalat F, Manoucheri S, Khademhosseini A. Engineering microscale topographies to control the cell-substrate interface. Biomaterials 2012; 33:5230-46. [PMID: 22521491 PMCID: PMC3619386 DOI: 10.1016/j.biomaterials.2012.03.079] [Citation(s) in RCA: 428] [Impact Index Per Article: 35.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 03/27/2012] [Indexed: 01/12/2023]
Abstract
Cells in their in vivo microenvironment constantly encounter and respond to a multitude of signals. While the role of biochemical signals has long been appreciated, the importance of biophysical signals has only recently been investigated. Biophysical cues are presented in different forms including topography and mechanical stiffness imparted by the extracellular matrix and adjoining cells. Microfabrication technologies have allowed for the generation of biomaterials with microscale topographies to study the effect of biophysical cues on cellular function at the cell-substrate interface. Topographies of different geometries and with varying microscale dimensions have been used to better understand cell adhesion, migration, and differentiation at the cellular and sub-cellular scales. Furthermore, quantification of cell-generated forces has been illustrated with micropillar topographies to shed light on the process of mechanotransduction. In this review, we highlight recent advances made in these areas and how they have been utilized for neural, cardiac, and musculoskeletal tissue engineering application.
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Affiliation(s)
- Mehdi Nikkhah
- Center for Biomedical Engineering, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Faramarz Edalat
- Center for Biomedical Engineering, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Sam Manoucheri
- Center for Biomedical Engineering, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - Ali Khademhosseini
- Center for Biomedical Engineering, Department of Medicine, Brigham and Women’s Hospital, Harvard Medical School, Boston, MA 02115, USA
- Harvard-MIT Division of Health Sciences and Technology, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
- Wyss Institute for Biologically Inspired Engineering, Harvard University, Boston, MA 02115, USA
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Modulating malignant epithelial tumor cell adhesion, migration and mechanics with nanorod surfaces. Biomed Microdevices 2011; 13:89-95. [PMID: 20830527 DOI: 10.1007/s10544-010-9473-7] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
The failure of tumor stents used for palliative therapy is due in part to the adhesion of tumor cells to the stent surface. It is therefore desirable to develop approaches to weaken the adhesion of malignant tumor cells to surfaces. We have previously developed SiO₂ coated nanorods that resist the adhesion of normal endothelial cells and fibroblasts. The adhesion mechanisms in malignant tumor cells are significantly altered from normal cells; therefore, it is unclear if nanorods can similarly resist tumor cell adhesion. In this study, we show that the morphology of tumor epithelial cells cultured on nanorods is rounded compared to flat surfaces and associated with decreased cellular stiffness and non-muscle myosin II phosphorylation. Tumor cell viability and proliferation was unchanged on nanorods. Adherent cell numbers were significantly decreased while single tumor cell motility was increased on nanorods compared to flat surfaces. Together, these results suggest that nanorods can be used to weaken malignant tumor cell adhesion, and therefore potentially improve tumor stent performance.
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Díaz C, Salvarezza RC, Fernández Lorenzo de Mele MA, Schilardi PL. Organization of Pseudomonas fluorescens on chemically different nano/microstructured surfaces. ACS APPLIED MATERIALS & INTERFACES 2010; 2:2530-2539. [PMID: 20726529 DOI: 10.1021/am100313z] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
This paper describes bacterial organization on nano/micropatterned surfaces with different chemical properties, which show different interactions with the biological systems (inert, biocompatible, and bactericide). These surfaces were prepared by molding techniques and exposed to Pseudomonas fluorescens (P. fluorescens) cultures. Results from atomic force microscopy and optical imaging demonstrate that the structure of P. fluorescens aggregates is strongly dependent on the surface topography while there is no clear linking with the physical-chemical surface properties (charge and contact angle) of the substrate immersed in abiotic culture media. We observe that regardless of the material when the surface pattern matches the bacterial size, bacterial assemblages involved in surface colonization are disorganized. The fact there is not a relationship between surface chemistry and bacterial organization can be explained by the coverage of the surfaces by adsorbed organic species coming from the culture medium. Viability assays indicate that copper behaves as a toxic substrate despite the presence of adsorbed molecules. The combination of surface traps and biocidal activity could act synergistically as a suitable strategy to limit bacterial spreading on implant materials.
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Affiliation(s)
- Carolina Díaz
- Instituto de Investigaciones Fisicoquímicas Teóricas y Aplicadas (INIFTA), Facultad de Ciencias Exactas, Universidad Nacional de La Plata-CONICET, Casilla de Correo 16, Sucursal 4, (1900) La Plata, Argentina
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Enhanced differentiation of retinal progenitor cells using microfabricated topographical cues. Biomed Microdevices 2010; 12:363-9. [PMID: 20077017 PMCID: PMC2859162 DOI: 10.1007/s10544-009-9392-7] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Due to the retina’s inability to replace photoreceptors lost during retinal degeneration, significant interest has been placed in methods to implant replacement cells. Polymer scaffolds are increasingly being studied as vehicles for cellular delivery to degenerated retinas. Previously, we fabricated poly(methyl methacrylate) thin film scaffolds that increased survival and integration of implanted retinal progenitor cells (RPCs). Additionally, these scaffolds minimized the trauma and cellular response associated with implantation of foreign bodies into mouse eyes. Here, we demonstrate that biodegradable polycaprolactone (PCL) thin film scaffolds can be fabricated with integrated microtopography. Microfabricated topography in a PCL thin film enhanced the attachment and organization of RPCs compared to unstructured surfaces. Using real-time quantitative polymerase chain reaction we also observed that attachment to microtopography induced cellular differentiation. RPCs grown on PCL thin films exhibited an increase in gene expression for the photoreceptor markers recoverin and rhodopsin, an increase in the glial and Müller cell marker GFAP, and a decrease in SOX2 gene expression (a marker for undifferentiated progenitor cells) compared to cells grown on unmodified tissue culture polystyrene (TCPS).
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Abstract
Biophysical cues encoded in the extracellular matrix (ECM) are increasingly being explored to control cell behavior in tissue engineering applications. Recently, we showed that cell adhesion to microtopographical structures (“micropegs”) can suppress proliferation in a manner that may be blunted by inhibiting cellular contractility, suggesting that this effect is related to altered cell-scaffold mechanotransduction. We now directly investigate this possibility at the microscale through a combination of live-cell imaging, single-cell mechanics methods, and analysis of gene expression. Using time-lapse imaging, we show that when cells break adhesive contacts with micropegs, they form F-actin-filled tethers that extend and then rupture at a maximum, critical length that is greater than trailing-edge tethers observed on topographically flat substrates. This critical tether length depends on myosin activation, with inhibition of Rho-associated kinase abolishing topography-dependent differences in tether length. Using cellular de-adhesion and atomic force microscopy indentation measurements, we show that the micropegs enhance cell-scaffold adhesive interactions without changing whole-cell elasticity. Moreover, micropeg adhesion increases expression of specific mechanotransductive genes, including RhoA GTPase and myosin heavy chain II, and, in myoblasts, the functional marker connexin 43. Together, our data support a model in which microtopographical cues alter the local mechanical microenvironment of cells by modulating adhesion and adhesion-dependent mechanotransductive signaling.
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Reynolds A, Moore JE, Naroo SA, Moore CBT, Shah S. Excimer laser surface ablation - a review. Clin Exp Ophthalmol 2010; 38:168-82. [DOI: 10.1111/j.1442-9071.2010.02230.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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Variola F, Vetrone F, Richert L, Jedrzejowski P, Yi JH, Zalzal S, Clair S, Sarkissian A, Perepichka DF, Wuest JD, Rosei F, Nanci A. Improving biocompatibility of implantable metals by nanoscale modification of surfaces: an overview of strategies, fabrication methods, and challenges. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2009; 5:996-1006. [PMID: 19360718 DOI: 10.1002/smll.200801186] [Citation(s) in RCA: 109] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
The human body is an intricate biochemical-mechanical system, with an exceedingly precise hierarchical organization in which all components work together in harmony across a wide range of dimensions. Many fundamental biological processes take place at surfaces and interfaces (e.g., cell-matrix interactions), and these occur on the nanoscale. For this reason, current health-related research is actively following a biomimetic approach in learning how to create new biocompatible materials with nanostructured features. The ultimate aim is to reproduce and enhance the natural nanoscale elements present in the human body and to thereby develop new materials with improved biological activities. Progress in this area requires a multidisciplinary effort at the interface of biology, physics, and chemistry. In this Review, the major techniques that have been adopted to yield novel nanostructured versions of familiar biomaterials, focusing particularly on metals, are presented and the way in which nanometric surface cues can beneficially guide biological processes, exerting influence on cellular behavior, is illustrated.
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Affiliation(s)
- Fabio Variola
- Laboratory for the Study of Calcified Tissues and Biomaterials, Faculté de Médecine Dentaire, Université de Montréal, QC, Canada
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