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Chummun I, Bhaw-Luximon A, Jhurry D. Modulating matrix-multicellular response using polysucrose-blended with poly-L-lactide or polydioxanone in electrospun scaffolds for skin tissue regeneration. J Biomed Mater Res A 2018; 106:3275-3291. [PMID: 30367544 DOI: 10.1002/jbm.a.36527] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2018] [Revised: 08/03/2018] [Accepted: 08/14/2018] [Indexed: 12/14/2022]
Abstract
Polysucrose (PSuc) is hydrophilic, has excellent biocompatibility with cells as a density gradient and is resistant to enzymes. Its use in electrospun mats for tissue engineering applications has not been investigated due to its amorphous nature. For spinnability and robustness, polysucrose was blended with poly-L-lactide (PLLA) and polydioxanone (PDX) respectively and electrospun into nanofibrous mats. Interaction with cells was assessed using L929 mouse fibroblasts and HaCaT keratinocytes separately and in co-culture. Effect of parameters such as porosity, fiber diameter, surface wettability and mechanical properties of mats on cell-scaffold interactions was studied. Depending on nature and composition of mats, fibroblasts showed dendritic, spindle or round cell morphologies along with the formation of lamellipodia, filopodia, fibrillar or fiber-like projections of 100 nm and 200-300 nm in diameter respectively from the periphery or center of cells. Granular extracellular matrix was formed on both PLLA-PSuc and PDX-PSuc 50-50 seeded with keratinocytes. Growth of keratinocytes was enhanced in co-culture with fibroblasts with the formation of a skin-like layer. Both cells showed the ability to form multilayer structures. The mats maintained their physical integrity during the period of study. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 3275-3291, 2018.
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Affiliation(s)
- Itisha Chummun
- Biomaterials, Drug Delivery and Nanotechnology Unit, Center for Biomedical and Biomaterials Research (CBBR), University of Mauritius, MSIRI Building, Réduit, Mauritius
| | - Archana Bhaw-Luximon
- Biomaterials, Drug Delivery and Nanotechnology Unit, Center for Biomedical and Biomaterials Research (CBBR), University of Mauritius, MSIRI Building, Réduit, Mauritius
| | - Dhanjay Jhurry
- Biomaterials, Drug Delivery and Nanotechnology Unit, Center for Biomedical and Biomaterials Research (CBBR), University of Mauritius, MSIRI Building, Réduit, Mauritius
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2
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Vilela P, Heuer-Jungemann A, El-Sagheer A, Brown T, Muskens OL, Smyth NR, Kanaras AG. Sensing of Vimentin mRNA in 2D and 3D Models of Wounded Skin Using DNA-Coated Gold Nanoparticles. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2018; 14:e1703489. [PMID: 29464860 DOI: 10.1002/smll.201703489] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 01/11/2018] [Indexed: 06/08/2023]
Abstract
Wound healing is a highly complex biological process, which is accompanied by changes in cell phenotype, variations in protein expression, and the production of active biomolecules. Currently, the detection of proteins in cells is done by immunostaining where the proteins in fixed cells are detected by labeled antibodies. However, immunostaining cannot provide information about dynamic processes in living cells, within the whole tissue. Here, an easy method is presented to detect the transition of epithelial to mesenchymal cells during wound healing. The method employs DNA-coated gold nanoparticle fluorescent nanoprobes to sense the production of Vimentin mRNA expressed in mesenchymal cells. Fluorescence microscopy is used to achieve temporal detection of Vimentin mRNA in wounds. 3D light-sheet microscopy is utilized to observe the dynamic expression of Vimentin mRNA spatially around the wounded site in skin tissue. The use of DNA-gold nanoprobes to detect mRNA expression during wound healing opens up new possibilities for the study of real-time mechanisms in complex biological processes.
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Affiliation(s)
- Patrick Vilela
- Physics and Astronomy, Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, SO17 1BJ, UK
| | - Amelie Heuer-Jungemann
- Physics and Astronomy, Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, SO17 1BJ, UK
| | - Afaf El-Sagheer
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
- Chemistry Branch, Department of Science and Mathematics, Faculty of Petroleum and Mining Engineering, Suez University, Suez, 43721, Egypt
| | - Tom Brown
- Chemistry Research Laboratory, Department of Chemistry, University of Oxford, 12 Mansfield Road, Oxford, OX1 3TA, UK
| | - Otto L Muskens
- Physics and Astronomy, Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, SO17 1BJ, UK
- Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Neil R Smyth
- Biological Sciences, Faculty of Natural and Environmental Sciences, University of Southampton, Southampton, SO17 1BJ, UK
| | - Antonios G Kanaras
- Physics and Astronomy, Faculty of Physical Sciences and Engineering, University of Southampton, Southampton, SO17 1BJ, UK
- Institute for Life Sciences, University of Southampton, Southampton, SO17 1BJ, UK
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Das SK, Gupta I, Cho YK, Zhang X, Uehara H, Muddana SK, Bernhisel AA, Archer B, Ambati BK. Vimentin knockdown decreases corneal opacity. Invest Ophthalmol Vis Sci 2014; 55:4030-40. [PMID: 24854859 DOI: 10.1167/iovs.13-13494] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
Abstract
PURPOSE Wound induced corneal fibrosis can lead to permanent visual impairment. Keratocyte activation and differentiation play a key role in fibrosis, and vimentin, a major structural type III intermediate filament, is a required component of this process. The purpose of our study was to develop a nonviral therapeutic strategy for treating corneal fibrosis in which we targeted the knockdown of vimentin. METHODS To determine the duration of plasmid expression in corneal keratocytes, we injected a naked plasmid expressing green fluorescent protein (GFP; pCMV-GFP) into an unwounded mouse corneal stroma. We then injected pCMV-GFP or plasmids expressing small hairpin RNA in the corneal wound injury model (full-thickness corneal incision) to evaluate opacification. RESULTS GFP expression peaked between days 1 and 3 and had prominent expression for 15 days. In the corneal wound injury model, we found that the GFP-positive cells demonstrated extensive dendritic-like processes that extended to adjacent cells, whereas the vimentin knockdown model showed significantly reduced corneal opacity. CONCLUSIONS These findings suggest that a nonviral gene therapeutic approach has potential for treating corneal fibrosis and ultimately reducing scarring.
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Affiliation(s)
- Subrata K Das
- Department of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
| | - Isha Gupta
- Department of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
| | - Yang Kyung Cho
- St. Vincent's Hospital, College of Medicine, The Catholic University of Korea, Suwon, South Korea
| | - Xiaohui Zhang
- Department of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
| | - Hironori Uehara
- Department of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
| | - Santosh Kumar Muddana
- Department of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
| | - Ashlie A Bernhisel
- Department of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
| | - Bonnie Archer
- Department of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
| | - Balamurali K Ambati
- Department of Ophthalmology, Moran Eye Center, University of Utah, Salt Lake City, Utah, United States
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Engineering a serum-resistant and thermostable vesicular stomatitis virus G glycoprotein for pseudotyping retroviral and lentiviral vectors. Gene Ther 2013; 20:807-15. [PMID: 23364315 PMCID: PMC3735647 DOI: 10.1038/gt.2013.1] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/04/2012] [Revised: 11/13/2012] [Accepted: 12/17/2012] [Indexed: 01/19/2023]
Abstract
Vesicular stomatitis virus G glycoprotein (VSV-G) is the most widely used envelope protein for retroviral and lentiviral vector pseudotyping; however, serum inactivation of VSV-G pseudotyped vectors is a significant challenge for in vivo gene delivery. To address this problem, we conducted directed evolution of VSV-G to increase its resistance to human serum neutralization. After six selection cycles, numerous common mutations were present. Based on their location within VSV-G, we analyzed whether substitutions in several surface exposed residues could endow viral vectors with higher resistance to serum. S162T, T230N, and T368A mutations enhanced serum resistance, and additionally K66T, T368A, and E380K substitutions increased the thermostability of VSV-G pseudotyped retroviral vectors, an advantageous byproduct of the selection strategy. Analysis of a number of combined mutants revealed that VSV-G harboring T230N + T368A or K66T + S162T + T230N + T368A mutations exhibited both higher in vitro resistance to human serum and higher thermostability, as well as enhanced resistance to rabbit and mouse serum. Finally, lentiviral vectors pseudotyped with these variants were more resistant to human serum in a murine model. These serum-resistant and thermostable VSV-G variants may aid the application of retroviral and lentiviral vectors to gene therapy.
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da Rocha-Azevedo B, Ho CH, Grinnell F. Fibroblast cluster formation on 3D collagen matrices requires cell contraction dependent fibronectin matrix organization. Exp Cell Res 2012; 319:546-55. [PMID: 23117111 DOI: 10.1016/j.yexcr.2012.10.005] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Revised: 10/08/2012] [Accepted: 10/09/2012] [Indexed: 12/21/2022]
Abstract
Fibroblasts incubated on 3D collagen matrices in serum or lysophosphatidic acid (LPA)-containing medium self-organize into clusters through a mechanism that requires cell contraction. However, in platelet-derived growth factor (PDGF)-containing medium, cells migrate as individuals and do not form clusters even though they constantly encounter each other. Here, we present evidence that a required function of cell contraction in clustering is formation of fibronectin (FN) fibrillar matrix. We found that in serum or LPA but not in PDGF or basal medium, cells organized FN (both serum and cellular) into a fibrillar, detergent-insoluble matrix. Cell clusters developed concomitant with FN matrix formation. FN fibrils accumulated beneath cells and along the borders of cell clusters in regions of cell-matrix tension. Blocking Rho kinase or myosin II activity prevented FN matrix assembly and cell clustering. Using siRNA silencing and function-blocking antibodies and peptides, we found that cell clustering and FN matrix assembly required α5β1 integrins and fibronectin. Cells were still able to exert contractile force and compact the collagen matrix under the latter conditions, which showed that contraction was not sufficient for cell clustering to occur. Our findings provide new insights into how procontractile (serum/LPA) and promigratory (PDGF) growth factor environments can differentially regulate FN matrix assembly by fibroblasts interacting with collagen matrices and thereby influence mesenchymal cell morphogenetic behavior under physiologic circumstances such as wound repair, morphogenesis and malignancy.
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Affiliation(s)
- Bruno da Rocha-Azevedo
- Department of Cell Biology, UT Southwestern Medical Center 5323, Harry Hines Boulevard, Dallas, TX 75390-9039, USA
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Hao M, Flynn K, Nien-Shy C, Jester BE, Winkler M, Brown DJ, La Schiazza O, Bille J, Jester JV. In vivo non-linear optical (NLO) imaging in live rabbit eyes using the Heidelberg Two-Photon Laser Ophthalmoscope. Exp Eye Res 2010; 91:308-14. [PMID: 20558159 DOI: 10.1016/j.exer.2010.06.007] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 06/02/2010] [Accepted: 06/09/2010] [Indexed: 12/13/2022]
Abstract
Imaging of non-linear optical (NLO) signals generated from the eye using ultrafast pulsed lasers has been limited to the study of ex vivo tissues because of the use of conventional microscopes with slow scan speeds. The purpose of this study was to evaluate the ability of a novel, high scan rate ophthalmoscope to generate NLO signals using an attached femtosecond laser. NLO signals were generated and imaged in live, anesthetized albino rabbits using a newly designed Heidelberg Two-Photon Laser Ophthalmoscope with attached 25 mW fs laser having a central wavelength of 780 nm, pulsewidth of 75 fs, and a repetition rate of 50 MHz. To assess two-photon excited fluorescent (TPEF) signal generation, cultured rabbit corneal fibroblasts (RCF) were first labeled by Blue-green fluorescent FluoSpheres (1 mum diameter) and then cells were micro-injected into the central cornea. Clumps of RCF cells could be detected by both reflectance and TPEF imaging at 6 h after injection. By 6 days, RCF containing fluorescent microspheres confirmed by TPEF showed a more spread morphology and had migrated from the original injection site. Overall, this study demonstrates the potential of using NLO microscopy to sequentially detect TPEF signals from live, intact corneas. We conclude that further refinement of the Two-photon laser Ophthalmoscope should lead to the development of an important, new clinical instrument capable of detecting NLO signals from patient corneas.
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Affiliation(s)
- Ming Hao
- Shanghai Jiaotong University, China
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López-García JS, Rivas Jara L, García-Lozano I, Murube J. Histopathologic Limbus Evolution After Alkaline Burns. Cornea 2007; 26:1043-8. [PMID: 17893531 DOI: 10.1097/ico.0b013e31812375fd] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
PURPOSE To study the histopathologic evolution of the corneal limbus after alkaline burns according to the clinical severity and therapy used. METHODS A prospective study of 15 eyes from 12 patients (9 men and 3 women) with moderate and severe alkaline burns was performed. All patients were divided into 2 groups in accordance with the clinical ocular severity and the therapy that was used: medical therapy, amniotic membrane transplantation (AMT), autologous limbal transplantation (ALT), and ALT combined with AMT (ALT + AMT). Biopsies were obtained from affected limbal areas immediately after the ocular burn and 9 months later. RESULTS Limbal regeneration was limited to small areas in patients with moderate burns treated with medical therapy; in contrast, the limbal structure showed significant stromal and epithelial regeneration in patients with moderate burns treated with AMT. There was an important stromal regeneration with an incomplete reepithelialization in patients with severe burns treated with AMT. Patients treated with ALT showed a good reepithelialization with a defective stromal regeneration. Epithelial and stromal regeneration was notable in patients with severe burns treated with ALT + AMT. CONCLUSIONS In patients with moderate alkaline burns, AMT improved both limbal stromal and epithelial regeneration more effectively than medical therapy. In patients with severe burns, the best reepithelialization and stromal regeneration were obtained with ALT + AMT.
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Jester JV, Ward BR, Takashima A, Gatlin J, Garcia JV, Cavanagh HD, Petroll WM. Four-dimensional multiphoton confocal microscopy: the new frontier in cellular imaging. Ocul Surf 2007; 2:10-20. [PMID: 17216072 DOI: 10.1016/s1542-0124(12)70020-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This paper reviews new developments in microscopy that combine gene transfer technology, multiphoton confocal fluorescence microscopy, live cell imaging and digital imaging techniques that provide unique insights into the complex physiological processes involved in tissue function at the cellular and subcellular level. The evolution of this novel, new technology is discussed with particular attention to earlier achievements in noninvasive ocular surface imaging. The practical basis of confocal microscopy, multiphoton confocal fluorescence microscopy, and the vital fluorescent labeling of cells in living tissues are also discussed. Additionally, one application using retroviral gene transfer to express enhanced green fluorescent protein in living wound healing fibroblasts is presented as an example of how living biology can be studied in situ in four dimensions (x, y, z, time).
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Affiliation(s)
- James V Jester
- Department of Ophthalmology, University of Texas Southwestern Medical Center at Dallas, Dallas, Texas 75390-9057, USA.
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Imanishi Y, Lodowski K, Koutalos Y. Two-photon microscopy: shedding light on the chemistry of vision. Biochemistry 2007; 46:9674-84. [PMID: 17676772 PMCID: PMC2718834 DOI: 10.1021/bi701055g] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
Two-photon microscopy (TPM) has come to occupy a prominent place in modern biological research with its ability to resolve the three-dimensional distribution of molecules deep inside living tissue. TPM can employ two different types of signals, fluorescence and second harmonic generation, to image biological structures with subcellular resolution. Two-photon excited fluorescence imaging is a powerful technique with which to monitor the dynamic behavior of the chemical components of tissues, whereas second harmonic imaging provides novel ways to study their spatial organization. Using TPM, great strides have been made toward understanding the metabolism, structure, signal transduction, and signal transmission in the eye. These include the characterization of the spatial distribution, transport, and metabolism of the endogenous retinoids, molecules essential for the detection of light, as well as the elucidation of the architecture of the living cornea. In this review, we present and discuss the current applications of TPM for the chemical and structural imaging of the eye. In addition, we address what we see as the future potential of TPM for eye research. This relatively new method of microscopy has been the subject of numerous technical improvements in terms of the optics and indicators used, improvements that should lead to more detailed biochemical characterizations of the eyes of live animals and even to imaging of the human eye in vivo.
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Affiliation(s)
- Yoshikazu Imanishi
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio
- To whom correspondence should be addressed:Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965. Phone: 216-368-5226. Fax: 216-368-1300. E-mail: (Y. I.); Department of Ophthalmology, Medical University of South, Carolina, Charleston, South Carolina 29425. Phone:843-792-9180. Fax: 843-792-1723. E-mail:(Y. K.)
| | - Kerrie Lodowski
- Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio
| | - Yiannis Koutalos
- Department of Ophthalmology, Medical University of South Carolina, Charleston, South, Carolina
- To whom correspondence should be addressed:Department of Pharmacology, School of Medicine, Case Western Reserve University, Cleveland, Ohio 44106-4965. Phone: 216-368-5226. Fax: 216-368-1300. E-mail: (Y. I.); Department of Ophthalmology, Medical University of South, Carolina, Charleston, South Carolina 29425. Phone:843-792-9180. Fax: 843-792-1723. E-mail:(Y. K.)
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Klausner EA, Peer D, Chapman RL, Multack RF, Andurkar SV. Corneal gene therapy. J Control Release 2007; 124:107-33. [PMID: 17707107 DOI: 10.1016/j.jconrel.2007.05.041] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2007] [Accepted: 05/15/2007] [Indexed: 12/23/2022]
Abstract
Gene therapy to the cornea can potentially correct inherited and acquired diseases of the cornea. Factors that facilitate corneal gene delivery are the accessibility and transparency of the cornea, its stability ex vivo and the immune privilege of the eye. Initial corneal gene delivery studies characterized the relationship between intraocular modes of administration and location of reporter gene expression. The challenge of achieving effective topical gene transfer, presumably due to tear flow, blinking and low penetration of the vector through epithlelial tight junctions left no alternative but invasive administration to the anterior chamber and corneal stroma. DNA vaccination, RNA interference and gene transfer of cytokines, growth factors and enzymes modulated the corneal microenvironment. Positive results were obtained in preclinical studies for prevention and treatment of corneal graft rejection, neovascularization, haze and herpetic stromal keratitis. These studies, corneal gene delivery systems and modes of administration, and considerations regarding the choice of animal species used are the focus of this review. Opportunities in the field of corneal gene therapy lie in expanding the array of corneal diseases investigated and in the implementation of recent designs of safer vectors with reduced immunogenicity and longer duration of gene expression.
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Affiliation(s)
- Eytan A Klausner
- Midwestern University Chicago College of Pharmacy, 555 31st Street, Downers Grove, IL 60515, United States.
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Tohill MP, Mann DJ, Mantovani CM, Wiberg M, Terenghi G. Green fluorescent protein is a stable morphological marker for schwann cell transplants in bioengineered nerve conduits. ACTA ACUST UNITED AC 2005; 10:1359-67. [PMID: 15588396 DOI: 10.1089/ten.2004.10.1359] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Bioengineered systems incorporate cultured cells to mimic the substituted tissue. A labeling method is necessary to monitor the survival of transplanted cells within the host. This labeling method must be compatible with the histochemical methods used for morphological analysis. This study assessed (1) The in vitro characteristics of Schwann cells (SCs) labeled with green fluorescent protein (GFP), (2) the in vivo effect of transplanted GFP-SCs in a model of peripheral nerve injury, and (3) the compatibility of GFP-SCs with immunofluorescence histochemical techniques. SCs were retrovirally labeled with GFP and their growth characteristics were compared with those of nontransduced SCs (ntSCs). GFP-SCs were seeded in a resorbable nerve conduit for grafting into a 1-cm gap in rat sciatic nerve. Grafts were harvested after 2 weeks and immunofluorescent staining was performed to measure axonal and SC regeneration distances and to identify GFP-SCs. Results of GFP-SC vitality assays did not vary significantly from those of ntSC assays. GFP-SCs were readily located ex vivo and stimulated significantly better axonal and SC regeneration distances in comparison with empty conduits. These findings show that GFP labeling does not have a deleterious effect on SCs and that it is a useful labeling method for the study of bioengineered systems.
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Affiliation(s)
- Mel P Tohill
- Blond McIndoe Research Laboratories, University of Manchester, Manchester, UK
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Coordinating epidermal growth factor-induced motility promotes efficient wound closure. Am J Physiol Cell Physiol 2004; 288:C109-21. [PMID: 15371256 DOI: 10.1152/ajpcell.00024.2003] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Wound healing is a response to injury that is initiated to reconstruct damaged tissue. In skin, reepithelialization involves both epithelial cells and fibroblasts and contributes to the reformation of a barrier between the external environment and internal milieu. Growth factors including epidermal growth factor (EGF) play important roles in promoting this process. In the present studies we employed CV-1 fibroblasts in a tissue culture model of reepithelialization to develop strategies for optimizing wound closure stimulated by EGF. We found that EGF enhanced cell motility within 6-8 h of EGF treatment in serum-free medium but wounds failed to close within 24 h. However, if medium on these cultures was exchanged for medium containing serum, cells pretreated with EGF closed new scrape wounds more rapidly than did cells that were not pretreated. These results indicate that serum factors work in concert with EGF to coordinate cell motility for efficient wound closure. Indeed, EGF enhanced the rate of wound closure in the presence of serum, and this effect also persisted for at least 24 h after EGF was removed. This coordination of EGF-induced cell motility was accompanied by an increase in the transient phosphorylation of ERK1 and ERK2. The persistent effects of EGF were blocked by transient exposure to reversible inhibitors of transcription and translation, indicating that the expression of new proteins mediated this response. We propose that EGF-stimulated CV-1 fibroblast motility is coordinated by a serum component that induces cell-cell adhesive properties consistent with an epithelial phenotype, thereby enhancing the reepithelialization process.
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Petroll WM, Cavanagh HD, Jester JV. Dynamic three-dimensional visualization of collagen matrix remodeling and cytoskeletal organization in living corneal fibroblasts. SCANNING 2004; 26:1-10. [PMID: 15000286 DOI: 10.1002/sca.4950260102] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/24/2023]
Abstract
The remodeling of extracellular matrices by cells plays a defining role in developmental morphogenesis and wound healing, as well as in tissue engineering. Three-dimensional (3-D) type I collagen matrices have been used extensively as an in vitro model for studying cell-induced matrix reorganization at the macroscopic level. However, few studies have directly assessed the dynamic process of 3-D matrix remodeling at the cellular and subcellular level. We recently developed an experimental model for investigating cell-matrix mechanical interactions by plating green fluorescen protein (GFP)-zyxin transfected cells inside fibrillar collagen matrices and performing high-magnification time-lapse differential interference microscopy (DIC) and wide-field fluorescent imaging. In this study, we extend this experimental model by performing four-dimensional (4-D) reflected light and fluorescent confocal imaging (using either visible light or multiphoton excitation) of living corneal fibroblasts transfected to express GFP-zyxin or GFP-alpha-actinin, 18 h after plating inside 3-D collagen matrices. Reflected light confocal imaging allowed detailed visualization of the cells and the fibrillar collagen surrounding them. By overlaying maximum intensity projections of reflected light and GFP-zyxin or GFP-alpha-actinin images and generating stereo pair reconstructions, 3-D interactions between focal adhesions and collagen fibrils in living cells could be visualized directly. Focal adhesions were generally oriented parallel to the direction of collagen fibril alignment in front of the cell. Killing the cells induced relaxation of transient cell-induced tension on the matrix; however, significant permanent remodeling always remained. Time-lapse 3-D imaging demonstrated an active response to the Rho-kinase inhibitor Y-27632, as indicated by cell elongation, extracellular matrix relaxation, and extension of pseudopodial processes. It is interesting that, at higher cell densities, groups of collagen fibrils were compacted and aligned into straps between neighboring cells. Overall, the continued development and application of this new approach should provide important insights into the basic underlying biochemical and biomechanical regulatory mechanisms controlling matrix remodeling by corneal fibroblasts.
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Affiliation(s)
- W Matthew Petroll
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas 75390-9057, USA.
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