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Petroll WM, Miron-Mendoza M, Sunkara Y, Ikebe HR, Sripathi NR, Hassaniardekani H. The impact of UV cross-linking on corneal stromal cell migration, differentiation and patterning. Exp Eye Res 2023; 233:109523. [PMID: 37271309 PMCID: PMC10825899 DOI: 10.1016/j.exer.2023.109523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2023] [Revised: 05/09/2023] [Accepted: 06/01/2023] [Indexed: 06/06/2023]
Abstract
Previous studies have demonstrated that UV cross-linking (CXL) increases stromal stiffness and produces alterations in extracellular matrix (ECM) microstructure. In order to investigate how CXL impacts both keratocyte differentiation and patterning within the stroma, and fibroblast migration and myofibroblast differentiation on top of the stroma, we combined CXL with superficial phototherapeutic keratectomy (PTK) in a rabbit model. Twenty-six rabbits underwent a 6 mm diameter, 70 μm deep phototherapeutic keratectomy (PTK) with an excimer laser to remove the epithelium and anterior basement membrane. In 14 rabbits, standard CXL was performed in the same eye immediately after PTK. Contralateral eyes served as controls. In vivo confocal microscopy through focusing (CMTF) was used to analyze corneal epithelial and stromal thickness, as well as stromal keratocyte activation and corneal haze. CMTF scans were collected pre-operatively, and from 7 to 120 days after the procedure. A subset of rabbits was sacrificed at each time point, and corneas were fixed and labeled in situ for multiphoton fluorescence microscopy and second harmonic generation imaging. In vivo and in situ imaging demonstrated that haze after PTK was primarily derived from a layer of myofibroblasts that formed on top of the native stroma. Over time, this fibrotic layer was remodeled into more transparent stromal lamellae, and quiescent cells replaced myofibroblasts. Migrating cells within the native stroma underneath the photoablated area were elongated, co-aligned with collagen, and lacked stress fibers. In contrast, following PTK + CXL, haze was derived primarily from highly reflective necrotic "ghost cells" in the anterior stroma, and fibrosis on top of the photoablated stroma was not observed at any time point evaluated. Cells formed clusters as they migrated into the cross-linked stromal tissue and expressed stress fibers; some cells at the edge of the CXL area also expressed α-SM actin, suggesting myofibroblast transformation. Stromal thickness increased significantly between 21 and 90 days after PTK + CXL (P < 0.001) and was over 35 μm higher than baseline at Day 90 (P < 0.05). Overall, these data suggest that cross-linking inhibits interlamellar cell movement, and that these changes lead to a disruption of normal keratocyte patterning and increased activation during stromal repopulation. Interestingly, CXL also prevents PTK-induced fibrosis on top of the stroma, and results in long term increases in stromal thickness in the rabbit model.
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Affiliation(s)
- W Matthew Petroll
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA; Department of Biomedical Engineering, UT Southwestern Medical Center, Dallas, TX, USA.
| | | | - Yukta Sunkara
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Hikaru R Ikebe
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
| | - Nishith R Sripathi
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, TX, USA
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Lam KH, Shihabeddin TZ, Awkal JA, Najjar AM, Miron-Mendoza M, Maruri DP, Varner VD, Petroll WM, Schmidtke DW. Effects of Topography and PDGF on the Response of Corneal Keratocytes to Fibronectin-Coated Surfaces. J Funct Biomater 2023; 14:217. [PMID: 37103307 PMCID: PMC10144166 DOI: 10.3390/jfb14040217] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Revised: 03/30/2023] [Accepted: 04/07/2023] [Indexed: 04/28/2023] Open
Abstract
During corneal wound healing, corneal keratocytes are exposed to both biophysical and soluble cues that cause them to transform from a quiescent state to a repair phenotype. How keratocytes integrate these multiple cues simultaneously is not well understood. To investigate this process, primary rabbit corneal keratocytes were cultured on substrates patterned with aligned collagen fibrils and coated with adsorbed fibronectin. After 2 or 5 days of culture, keratocytes were fixed and stained to assess changes in cell morphology and markers of myofibroblastic activation by fluorescence microscopy. Initially, adsorbed fibronectin had an activating effect on the keratocytes as evidenced by changes in cell shape, stress fiber formation, and expression of alpha-smooth muscle actin (α-SMA). The magnitude of these effects depended upon substrate topography (i.e., flat substrate vs aligned collagen fibrils) and decreased with culture time. When keratocytes were simultaneously exposed to adsorbed fibronectin and soluble platelet-derived growth factor-BB (PDGF-BB), the cells elongated and had reduced expression of stress fibers and α-SMA. In the presence of PDGF-BB, keratocytes plated on the aligned collagen fibrils elongated in the direction of the fibrils. These results provide new information on how keratocytes respond to multiple simultaneous cues and how the anisotropic topography of aligned collagen fibrils influences keratocyte behavior.
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Affiliation(s)
- Kevin H. Lam
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Tarik Z. Shihabeddin
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Jacob A. Awkal
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Alex M. Najjar
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Miguel Miron-Mendoza
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Daniel P. Maruri
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Victor D. Varner
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - W. Matthew Petroll
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
- Department of Biomedical Engineering, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - David W. Schmidtke
- Department of Bioengineering, University of Texas at Dallas, Richardson, TX 75080, USA
- Department of Surgery, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Maruri DP, Miron-Mendoza M, Kivanany PB, Hack JM, Schmidtke DW, Petroll WM, Varner VD. ECM Stiffness Controls the Activation and Contractility of Corneal Keratocytes in Response to TGF-β1. Biophys J 2020; 119:1865-1877. [PMID: 33080219 DOI: 10.1016/j.bpj.2020.08.040] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2020] [Revised: 07/31/2020] [Accepted: 08/31/2020] [Indexed: 12/19/2022] Open
Abstract
After surgery or traumatic injury, corneal wound healing can cause a scarring response that stiffens the tissue and impairs ocular function. This fibrosis is caused in part by the activation of corneal keratocytes from a native mechanically quiescent state to an activated myofibroblastic state. This transformation is tied to signaling downstream of transforming growth factor-β1 (TGF-β1). Here, to better understand how biochemical and biophysical cues interact to regulate keratocyte activation and contractility, we cultured primary rabbit corneal keratocytes on flexible substrata of varying stiffness in the presence (or absence) of TGF-β1. Time-lapse fluorescence microscopy was used to assess changes in keratocyte morphology, as well as to quantify the dynamic traction stresses exerted by cells under different experimental conditions. In other experiments, keratocytes were fixed after 5 days of culture and stained for markers of both contractility and myofibroblastic activation. Treatment with TGF-β1 elicited distinct phenotypes on substrata of different stiffnesses. Cells on soft (1 kPa) gels formed fewer stress fibers and retained a more dendritic morphology, indicative of a quiescent keratocyte phenotype. Keratocytes cultured on stiff (10 kPa) gels or collagen-coated glass coverslips, however, had broad morphologies, formed abundant stress fibers, exhibited greater levels of α-smooth muscle actin (α-SMA) expression, and exerted larger traction forces. Confocal images of phospho-myosin light chain (pMLC) immunofluorescence, moreover, revealed stiffness-dependent differences in the subcellular distribution of actomyosin contractility, with pMLC localized at the tips of thin cellular processes in mechanically quiescent cells. Importantly, keratocytes cultured in the absence of TGF-β1 showed no stiffness-dependent differences in α-SMA immunofluorescence, suggesting that a stiff microenvironment alone is insufficient to induce myofibroblastic activation. Taken together, these data suggest that changes in ECM stiffness can modulate the morphology, cytoskeletal organization, and subcellular pattern of force generation in corneal keratocytes treated with TGF-β1.
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Affiliation(s)
- Daniel P Maruri
- Department of Bioengineering, University of Texas at Dallas, Richardson, Texas
| | - Miguel Miron-Mendoza
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Pouriska B Kivanany
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Joshua M Hack
- Department of Bioengineering, University of Texas at Dallas, Richardson, Texas
| | - David W Schmidtke
- Department of Bioengineering, University of Texas at Dallas, Richardson, Texas; Department of Surgery, University of Texas Southwestern Medical Center, Dallas, Texas
| | - W Matthew Petroll
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, Texas
| | - Victor D Varner
- Department of Bioengineering, University of Texas at Dallas, Richardson, Texas; Department of Surgery, University of Texas Southwestern Medical Center, Dallas, Texas.
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Miron-Mendoza M, Graham E, Manohar S, Petroll WM. Fibroblast-fibronectin patterning and network formation in 3D fibrin matrices. Matrix Biol 2017; 64:69-80. [PMID: 28602859 PMCID: PMC5705415 DOI: 10.1016/j.matbio.2017.06.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2017] [Revised: 05/26/2017] [Accepted: 06/01/2017] [Indexed: 12/25/2022]
Abstract
PURPOSE We previously reported that fibroblasts migrating within 3-D collagen matrices move independently, whereas fibroblasts within 3-D fibrin matrices form an interconnected network. Similar networks have been identified previously during in vivo corneal wound healing. In this study, we investigate the role of fibronectin in mediating this mechanism of collective cell spreading, migration and patterning. METHODS To assess cell spreading, corneal fibroblasts were plated within fibrillar collagen or fibrin matrices. To assess migration, compacted cell-populated collagen matrices were nested inside cell-free fibrin matrices. Constructs were cultured in serum-free media containing PDGF, with or without RGD peptide, anti-α5 or anti-fibronectin blocking antibodies. In some experiments, LifeAct and fluorescent fibronectin were used to allow dynamic assessment of cell-induced fibronectin reorganization. 3-D and 4-D imaging were used to assess cell mechanical behavior, connectivity, F-actin, α5 integrin and fibronectin organization. RESULTS Corneal fibroblasts within 3-D fibrin matrices formed an interconnected network that was lined with cell-secreted fibronectin. Live cell imaging demonstrated that fibronectin tracks were formed at the leading edge of spreading and migrating cells. Furthermore, fibroblasts preferentially migrated through fibronectin tracks laid down by other cells. Interfering with cell-fibronectin binding with RGD, anti α5 integrin or anti fibronectin antibodies inhibited cell spreading and migration through fibrin, but did not affect cell behavior in collagen. CONCLUSIONS In this study, a novel mode of cell patterning was identified in which corneal fibroblasts secrete and attach to fibronectin via α5β1 integrin to facilitate spreading and migration within 3-D fibrin matrices, resulting in the formation of localized fibronectin tracks. Other cells use these fibronectin tracks as conduits, resulting in an interconnected cell-fibronectin network.
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Affiliation(s)
- Miguel Miron-Mendoza
- Department of Ophthalmology, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9057, United States
| | - Eric Graham
- Department of Ophthalmology, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9057, United States
| | - Sujal Manohar
- Department of Ophthalmology, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9057, United States
| | - W Matthew Petroll
- Department of Ophthalmology, UT Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9057, United States.
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Petroll WM, Miron-Mendoza M. Mechanical interactions and crosstalk between corneal keratocytes and the extracellular matrix. Exp Eye Res 2015; 133:49-57. [PMID: 25819454 PMCID: PMC4379425 DOI: 10.1016/j.exer.2014.09.003] [Citation(s) in RCA: 44] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2014] [Revised: 09/09/2014] [Accepted: 09/11/2014] [Indexed: 12/13/2022]
Abstract
The generation of cellular forces and the application of these physical forces to the ECM play a central role in mediating matrix patterning and remodeling during fundamental processes such as developmental morphogenesis and wound healing. In addition to growth factors and other biochemical factors that can modulate the keratocyte mechanical phenotype, another key player in the regulation of cell-induced ECM patterning is the mechanical state of the ECM itself. In this review we provide an overview of the biochemical and biophysical factors regulating the mechanical interactions between corneal keratocytes and the stromal ECM at the cellular level. We first provide an overview of how Rho GTPases regulate the sub-cellular pattern of force generation by corneal keratocytes, and the impact these forces have on the surrounding ECM. We next review how feedback from local matrix structural and mechanical properties can modulate keratocyte phenotype and mechanical activity. Throughout this review, we provide examples of how these biophysical interactions may contribute to clinical outcomes, with a focus on corneal wound healing.
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Affiliation(s)
- W Matthew Petroll
- Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9057, USA.
| | - Miguel Miron-Mendoza
- Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd., Dallas, TX 75390-9057, USA
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Miron-Mendoza M, Graham E, Kivanany P, Quiring J, Petroll WM. The Role of Thrombin and Cell Contractility in Regulating Clustering and Collective Migration of Corneal Fibroblasts in Different ECM Environments. Invest Ophthalmol Vis Sci 2015; 56:2079-90. [PMID: 25736789 PMCID: PMC4373543 DOI: 10.1167/iovs.15-16388] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2015] [Accepted: 02/24/2015] [Indexed: 11/24/2022] Open
Abstract
PURPOSE We previously reported that extracellular matrix composition (fibrin versus collagen) modulates the pattern of corneal fibroblast spreading and migration in 3-D culture. In this study, we investigate the role of thrombin and cell contractility in mediating these differences in cell behavior. METHODS To assess cell spreading, corneal fibroblasts were plated on top of fibrillar collagen and fibrin matrices. To assess 3-dimensional cell migration, compacted collagen matrices seeded with corneal fibroblasts were embedded inside acellular collagen or fibrin matrices. Constructs were cultured in serum-free media containing platelet-derived growth factor (PDGF), with or without thrombin, the Rho kinase inhibitor Y-27632, and/or the myosin II inhibitor blebbistatin. We used 3-dimensional and 4-dimensional imaging to assess cell mechanical behavior, connectivity and cytoskeletal organization. RESULTS Thrombin stimulated increased contractility of corneal fibroblasts. Thrombin also induced Rho kinase-dependent clustering of cells plated on top of compliant collagen matrices, but not on rigid substrates. In contrast, cells on fibrin matrices coalesced into clusters even when Rho kinase was inhibited. In nested matrices, cells always migrated independently through collagen, even in the presence of thrombin. In contrast, cells migrating into fibrin formed an interconnected network. Both Y-27632 and blebbistatin reduced the migration rate in fibrin, but cells continued to migrate collectively. CONCLUSIONS The results suggest that while thrombin-induced actomyosin contraction can induce clustering of fibroblasts plated on top of compliant collagen matrices, it does not induce collective cell migration inside 3-D collagen constructs. Furthermore, increased contractility is not required for clustering or collective migration of corneal fibroblasts interacting with fibin.
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Affiliation(s)
- Miguel Miron-Mendoza
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, Texas, United States
| | - Eric Graham
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, Texas, United States
| | - Pouriska Kivanany
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, Texas, United States
| | - Jonathan Quiring
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, Texas, United States
| | - W Matthew Petroll
- Department of Ophthalmology, UT Southwestern Medical Center, Dallas, Texas, United States
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Miron-Mendoza M, Koppaka V, Zhou C, Petroll WM. Techniques for assessing 3-D cell-matrix mechanical interactions in vitro and in vivo. Exp Cell Res 2013; 319:2470-80. [PMID: 23819988 PMCID: PMC3826791 DOI: 10.1016/j.yexcr.2013.06.018] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2013] [Revised: 06/22/2013] [Accepted: 06/24/2013] [Indexed: 12/19/2022]
Abstract
Cellular interactions with extracellular matrices (ECM) through the application of mechanical forces mediate numerous biological processes including developmental morphogenesis, wound healing and cancer metastasis. They also play a key role in the cellular repopulation and/or remodeling of engineered tissues and organs. While 2-D studies can provide important insights into many aspects of cellular mechanobiology, cells reside within 3-D ECMs in vivo, and matrix structure and dimensionality have been shown to impact cell morphology, protein organization and mechanical behavior. Global measurements of cell-induced compaction of 3-D collagen matrices can provide important insights into the regulation of overall cell contractility by various cytokines and signaling pathways. However, to understand how the mechanics of cell spreading, migration, contraction and matrix remodeling are regulated at the molecular level, these processes must also be studied in individual cells. Here we review the evolution and application of techniques for imaging and assessing local cell-matrix mechanical interactions in 3-D culture models, tissue explants and living animals.
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Affiliation(s)
- Miguel Miron-Mendoza
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Vindhya Koppaka
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Chengxin Zhou
- Graduate Program in Biomedical Engineering, University of Texas Southwestern Medical Center, Dallas, TX
| | - W. Matthew Petroll
- Department of Ophthalmology, University of Texas Southwestern Medical Center, Dallas, TX
- Graduate Program in Biomedical Engineering, University of Texas Southwestern Medical Center, Dallas, TX
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Miron-Mendoza M, Lin X, Ma L, Ririe P, Petroll WM. Individual versus collective fibroblast spreading and migration: regulation by matrix composition in 3D culture. Exp Eye Res 2012; 99:36-44. [PMID: 22838023 PMCID: PMC3571722 DOI: 10.1016/j.exer.2012.03.015] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Extracellular matrix (ECM) supplies both physical and chemical signals to cells and provides a substrate through which fibroblasts migrate during wound repair. To directly assess how ECM composition regulates this process, we used a nested 3D matrix model in which cell-populated collagen buttons were embedded in cell-free collagen or fibrin matrices. Time-lapse microscopy was used to record the dynamic pattern of cell migration into the outer matrices, and 3D confocal imaging was used to assess cell connectivity and cytoskeletal organization. Corneal fibroblasts stimulated with PDGF migrated more rapidly into collagen as compared to fibrin. In addition, the pattern of fibroblast migration into fibrin and collagen ECMs was strikingly different. Corneal fibroblasts migrating into collagen matrices developed dendritic processes and moved independently, whereas cells migrating into fibrin matrices had a more fusiform morphology and formed an interconnected meshwork. A similar pattern was observed when using dermal fibroblasts, suggesting that this response is not unique to corneal cells. We next cultured corneal fibroblasts within and on top of standard collagen and fibrin matrices to assess the impact of ECM composition on the cell spreading response. Similar differences in cell morphology and connectivity were observed – cells remained separated on collagen but coalesced into clusters on fibrin. Cadherin was localized to junctions between interconnected cells, whereas fibronectin was present both between cells and at the tips of extending cell processes. Cells on fibrin matrices also developed more prominent stress fibers than those on collagen matrices. Importantly, these spreading and migration patterns were consistently observed on both rigid and compliant substrates, thus differences in ECM mechanical stiffness were not the underlying cause. Overall, these results demonstrate for the first time that ECM protein composition alone (collagen vs. fibrin) can induce a switch from individual to collective fibroblast spreading and migration in 3D culture. Similar processes may also influence cell behavior during wound healing, development, tumor invasion and repopulation of engineered tissues.
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Affiliation(s)
- Miguel Miron-Mendoza
- Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas 75390-9057
| | - Xihui Lin
- Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas 75390-9057
| | - Lisha Ma
- Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas 75390-9057
| | - Peter Ririe
- Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas 75390-9057
| | - W. Matthew Petroll
- Department of Ophthalmology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd, Dallas, Texas 75390-9057
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Miron-Mendoza M, Seemann J, Grinnell F. The differential regulation of cell motile activity through matrix stiffness and porosity in three dimensional collagen matrices. Biomaterials 2010; 31:6425-35. [PMID: 20537378 DOI: 10.1016/j.biomaterials.2010.04.064] [Citation(s) in RCA: 160] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Accepted: 04/29/2010] [Indexed: 10/19/2022]
Abstract
In three dimensional collagen matrices, cell motile activity results in collagen translocation, cell spreading and cell migration. Cells can penetrate into the matrix as well as spread and migrate along its surface. In the current studies, we quantitatively characterize collagen translocation, cell spreading and cell migration in relationship to collagen matrix stiffness and porosity. Collagen matrices prepared with 1-4 mg/ml collagen exhibited matrix stiffness (storage modulus measured by oscillating rheometry) increasing from 4 to 60 Pa and matrix porosity (measured by scanning electron microscopy) decreasing from 4 to 1 microm(2). Over this collagen concentration range, the consequences of cell motile activity changed markedly. As collagen concentration increased, cells no longer were able to cause translocation of collagen fibrils. Cell migration increased and cell spreading changed from dendritic to more flattened and polarized morphology depending on location of cells within or on the surface of the matrix. Collagen translocation appeared to depend primarily on matrix stiffness, whereas cell spreading and migration were less dependent on matrix stiffness and more dependent on collagen matrix porosity.
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Affiliation(s)
- Miguel Miron-Mendoza
- Department of Cell Biology, University of Texas Southwestern Medical Center, 5323 Harry Hines Blvd Dallas, TX 75390-9039, USA
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Bisel B, Wang Y, Wei JH, Xiang Y, Tang D, Miron-Mendoza M, Yoshimura SI, Nakamura N, Seemann J. ERK regulates Golgi and centrosome orientation towards the leading edge through GRASP65. ACTA ACUST UNITED AC 2008; 182:837-43. [PMID: 18762583 PMCID: PMC2528584 DOI: 10.1083/jcb.200805045] [Citation(s) in RCA: 135] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Directed cell migration requires the orientation of the Golgi and centrosome toward the leading edge. We show that stimulation of interphase cells with the mitogens epidermal growth factor or lysophosphatidic acid activates the extracellular signal-regulated kinase (ERK), which phosphorylates the Golgi structural protein GRASP65 at serine 277. Expression of a GRASP65 Ser277 to alanine mutant or a GRASP65 1-201 truncation mutant, neither of which can be phosphorylated by ERK, prevents Golgi orientation to the leading edge in a wound assay. We show that phosphorylation of GRASP65 with recombinant ERK leads to the loss of GRASP65 oligomerization and causes Golgi cisternal unstacking. Furthermore, preventing Golgi polarization by expressing mutated GRASP65 inhibits centrosome orientation, which is rescued upon disassembly of the Golgi structure by brefeldin A. We conclude that Golgi remodeling, mediated by phosphorylation of GRASP65 by ERK, is critical for the establishment of cell polarity in migrating cells.
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Affiliation(s)
- Blaine Bisel
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
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Menezes GC, Miron-Mendoza M, Ho CH, Jiang H, Grinnell F. Oncogenic Ras-transformed human fibroblasts exhibit differential changes in contraction and migration in 3D collagen matrices. Exp Cell Res 2008; 314:3081-91. [PMID: 18708049 DOI: 10.1016/j.yexcr.2008.07.018] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2008] [Revised: 07/18/2008] [Accepted: 07/22/2008] [Indexed: 02/06/2023]
Abstract
Tractional force exerted by tissue cells in 3D collagen matrices can be utilized for matrix remodeling or cell migration. The interrelationship between these motile processes is not well understood. The current studies were carried out to test the consequences of oncogenic Ras (H-Ras(V12)) transformation on human fibroblast contraction and migration in 3D collagen matrices. Beginning with hTERT-immortalized cells, we prepared fibroblasts stably transformed with E6/E7 and with the combination HPV16 E6/E7 and H-Ras(V12). Oncogenic Ras-transformed cells lost contact inhibition of cell growth, formed colonies in soft agar and were unable to make adherens junctions. We observed no changes in the extent or growth factor dependence of collagen matrix contraction (floating or stress-relaxation) by oncogenic Ras-transformed cells. On the other hand, transformed cells in nested collagen matrices lost not only growth factor selectivity, but also cell-matrix density-dependent inhibition of migration. These findings demonstrate differential regulation of collagen matrix contraction and cell migration in 3D collagen matrices.
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Affiliation(s)
- Gustavo C Menezes
- Universidade Federal do Rio de Janeiro, Instituto de Biofisica Carlos Chagas Filho, Rio de Janeiro, Brazil
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Miron-Mendoza M, Seemann J, Grinnell F. Collagen fibril flow and tissue translocation coupled to fibroblast migration in 3D collagen matrices. Mol Biol Cell 2008; 19:2051-8. [PMID: 18321993 PMCID: PMC2366841 DOI: 10.1091/mbc.e07-09-0930] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2007] [Revised: 02/06/2008] [Accepted: 02/19/2008] [Indexed: 11/11/2022] Open
Abstract
In nested collagen matrices, human fibroblasts migrate from cell-containing dermal equivalents into surrounding cell-free outer matrices. Time-lapse microscopy showed that in addition to cell migration, collagen fibril flow occurred in the outer matrix toward the interface with the dermal equivalent. Features of this flow suggested that it depends on the same cell motile machinery that normally results in cell migration. Collagen fibril flow was capable of producing large-scale tissue translocation as shown by closure of a approximately 1-mm gap between paired dermal equivalents in floating, nested collagen matrices. Our findings demonstrate that when fibroblasts interact with collagen matrices, tractional force exerted by the cells can couple to matrix translocation as well as to cell migration.
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Affiliation(s)
- Miguel Miron-Mendoza
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039
| | - Joachim Seemann
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039
| | - Frederick Grinnell
- Department of Cell Biology, University of Texas Southwestern Medical Center, Dallas, TX 75390-9039
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