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Ravelli C, Grillo E, Corsini M, Coltrini D, Presta M, Mitola S. β3 Integrin Promotes Long-Lasting Activation and Polarization of Vascular Endothelial Growth Factor Receptor 2 by Immobilized Ligand. Arterioscler Thromb Vasc Biol 2015; 35:2161-71. [PMID: 26293466 PMCID: PMC4894810 DOI: 10.1161/atvbaha.115.306230] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2015] [Accepted: 08/04/2015] [Indexed: 11/16/2022]
Abstract
Supplemental Digital Content is available in the text. Objective— During neovessel formation, angiogenic growth factors associate with the extracellular matrix. These immobilized factors represent a persistent stimulus for the otherwise quiescent endothelial cells (ECs), driving directional EC migration and proliferation and leading to new blood vessel growth. Vascular endothelial growth factor receptor 2 (VEGFR2) is the main mediator of angiogenesis. Although VEGFR2 signaling has been deeply characterized, little is known about its subcellular localization during neovessel formation. Aim of this study was the characterization and molecular determinants of activated VEGFR2 localization in ECs during neovessel formation in response to matrix-immobilized ligand. Approach and Results— Here we demonstrate that ECs stimulated by extracellular matrix–associated gremlin, a noncanonical VEGFR2 ligand, are polarized and relocate the receptor in close contact with the angiogenic factor–enriched matrix both in vitro and in vivo. GM1 (monosialotetrahexosylganglioside)-positive planar lipid rafts, β3 integrin receptors, and the intracellular signaling transducers focal adhesion kinase and RhoA (Ras homolog gene family, member A) cooperate to promote VEGFR2 long-term polarization and activation. Conclusions— A ligand anchored to the extracellular matrix induces VEGFR2 polarization in ECs. Long-lasting VEGFR2 relocation is closely dependent on lipid raft integrity and activation of β3 integrin pathway. The study of the endothelial responses to immobilized growth factors may offer insights into the angiogenic process in physiological and pathological conditions, including cancer, and for a better engineering of synthetic tissue scaffolds to blend with the host vasculature.
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Affiliation(s)
- Cosetta Ravelli
- From the Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Elisabetta Grillo
- From the Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Michela Corsini
- From the Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Daniela Coltrini
- From the Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy
| | - Marco Presta
- From the Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy.
| | - Stefania Mitola
- From the Department of Molecular and Translational Medicine, University of Brescia, Brescia, Italy.
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Smith RJ, Koobatian MT, Shahini A, Swartz DD, Andreadis ST. Capture of endothelial cells under flow using immobilized vascular endothelial growth factor. Biomaterials 2015; 51:303-312. [PMID: 25771020 PMCID: PMC4361797 DOI: 10.1016/j.biomaterials.2015.02.025] [Citation(s) in RCA: 53] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2014] [Revised: 01/27/2015] [Accepted: 02/01/2015] [Indexed: 02/09/2023]
Abstract
We demonstrate the ability of immobilized vascular endothelial growth factor (VEGF) to capture endothelial cells (EC) with high specificity under fluid flow. To this end, we engineered a surface consisting of heparin bound to poly-L-lysine to permit immobilization of VEGF through the C-terminal heparin-binding domain. The immobilized growth factor retained its biological activity as shown by proliferation of EC and prolonged activation of KDR signaling. Using a microfluidic device we assessed the ability to capture EC under a range of shear stresses from low (0.5 dyne/cm2) to physiological (15 dyne/cm2). Capture was significant for all shear stresses tested. Immobilized VEGF was highly selective for EC as evidenced by significant capture of human umbilical vein and ovine pulmonary artery EC but no capture of human dermal fibroblasts, human hair follicle derived mesenchymal stem cells, or mouse fibroblasts. Further, VEGF could capture EC from mixtures with non-EC under low and high shear conditions as well as from complex fluids like whole human blood under high shear. Our findings may have far reaching implications, as they suggest that VEGF could be used to promote endothelialization of vascular grafts or neovascularization of implanted tissues by rare but continuously circulating EC.
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Affiliation(s)
- Randall J Smith
- Department of Biomedical Engineering, University at Buffalo, State University of New York, Amherst, NY 14260-4200, USA
| | - Maxwell T Koobatian
- Department of Physiology and Biophysics, University at Buffalo, State University of New York, Amherst, NY 14260-4200, USA
| | - Aref Shahini
- Department of Chemical and Biological Engineering, University at Buffalo, State University of New York, Amherst, NY 14260-4200, USA
| | - Daniel D Swartz
- Department of Physiology and Biophysics, University at Buffalo, State University of New York, Amherst, NY 14260-4200, USA; Department of Pediatrics, Women and Children's Hospital of Buffalo, University at Buffalo, State University of New York, Amherst, NY 14260-4200, USA; Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, State University of New York, Amherst, NY 14260-4200, USA
| | - Stelios T Andreadis
- Department of Chemical and Biological Engineering, University at Buffalo, State University of New York, Amherst, NY 14260-4200, USA; Department of Biomedical Engineering, University at Buffalo, State University of New York, Amherst, NY 14260-4200, USA; Center of Excellence in Bioinformatics and Life Sciences, University at Buffalo, State University of New York, Amherst, NY 14260-4200, USA.
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3
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Hume PS, He J, Haskins K, Anseth KS. Strategies to reduce dendritic cell activation through functional biomaterial design. Biomaterials 2012; 33:3615-25. [PMID: 22361099 DOI: 10.1016/j.biomaterials.2012.02.009] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2012] [Accepted: 02/02/2012] [Indexed: 10/28/2022]
Abstract
Dendritic cells play a key role in determining adaptive immunity, and there is growing interest in characterizing and manipulating the interactions between dendritic cells and biomaterial surfaces. Contact with several common biomaterials can induce the maturation of immature dendritic cells, but substrates that reduce dendritic cell maturation are of particular interest within the field of cell-based therapeutics where the goal is to reduce the immune response to cell-laden material carriers. In this study, we use a materials-based strategy to functionalize poly(ethylene glycol) hydrogels with immobilized immunosuppressive factors (TGF-β1 and IL-10) to reduce the maturation of immature dendritic cells. TGF-β1 and IL-10 are commonly employed as soluble factors to program dendritic cells in vitro, and we demonstrate that these proteins retain bioactivity towards dendritic cells when immobilized on hydrogel surfaces. Following stimulation with lipopolysaccharide (LPS) and/or cytokines, a dendritic cell line interacting with the surfaces of immunosuppressive hydrogels expressed reduced markers of maturation, including IL-12 and MHCII. The bioactivity of these immunomodulatory hydrogels was further confirmed with primary bone marrow-derived dendritic cells (BMDCs) isolated from non-obese diabetic (NOD) mice, as quantified by a decrease in activation markers and a significantly reduced capacity to activate T cells. Furthermore, by introducing a second signal to promote BMDC-material interactions combined with the presentation of tolerizing signals, the multifunctional PEG hydrogels were found to further increase signaling towards BMDCs, as evidenced by greater reductions in maturation markers.
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Affiliation(s)
- Patrick S Hume
- Department of Chemical and Biological Engineering, University of Colorado, 424 UCB, Boulder, CO 80309, USA
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Recker T, Haamann D, Schmitt A, Küster A, Klee D, Barth S, Müller-Newen G. Directed Covalent Immobilization of Fluorescently Labeled Cytokines. Bioconjug Chem 2011; 22:1210-20. [DOI: 10.1021/bc200079e] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Affiliation(s)
- Tobias Recker
- Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University, Aachen, Germany
| | | | - Anne Schmitt
- Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Andrea Küster
- Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University, Aachen, Germany
| | - Doris Klee
- ITMC/DWI, RWTH Aachen University, Aachen, Germany
| | - Stefan Barth
- Department of Experimental Medicine and Immunotherapy, Institute for Applied Medical Engineering, Aachen, Germany
- Department of Pharmaceutical Product Development, Fraunhofer Institute for Molecular Biology and Applied Ecology, Aachen, Germany
| | - Gerhard Müller-Newen
- Institute of Biochemistry and Molecular Biology, Medical School, RWTH Aachen University, Aachen, Germany
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Chiu LLY, Weisel RD, Li RK, Radisic M. Defining conditions for covalent immobilization of angiogenic growth factors onto scaffolds for tissue engineering. J Tissue Eng Regen Med 2011; 5:69-84. [PMID: 20717888 DOI: 10.1002/term.292] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2009] [Accepted: 02/25/2010] [Indexed: 12/30/2022]
Abstract
Rapid vascularization of engineered tissues in vitro and in vivo remains one of the key limitations in tissue engineering. We propose that angiogenic growth factors covalently immobilized on scaffolds for tissue engineering can be used to accomplish this goal. The main objectives of this work were: (a) to derive desirable experimental conditions for the covalent immobilization of vascular endothelial growth factor (VEGF) and angiopoietin-1 (Ang1) on porous collagen scaffolds; and (b) to determine whether primary endothelial cells respond to these scaffolds with covalently immobilized angiogenic factors. VEGF and Ang1 were covalently immobilized onto porous collagen scaffolds, using 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide hydrochloride (EDC) chemistry. To improve covalent immobilization conditions: (a) different reaction buffers [phosphate-buffered saline (PBS), distilled water, or 2-(N-morpholino)ethanesulphonic acid (MES)] were used; and (b) step immobilization was compared to bulk immobilization. In step immobilization, growth factors are applied after EDC activation of the scaffold, while in bulk immobilization, reagents are simultaneously applied to the scaffold. PBS as the reaction buffer resulted in higher amounts of VEGF and Ang1 immobilized (ELISA), higher cell proliferation rates (XTT) and increased lactate metabolism compared to water and MES as the reaction buffers. Step immobilization in PBS buffer was also more effective than bulk immobilization. Immobilized growth factors resulted in higher cell proliferation and lactate metabolism compared to soluble growth factors used at comparable concentrations. Tube formation by CD31-positive cells was also observed in collagen scaffolds with immobilized VEGF or Ang1 using H5V and primary rat aortic endothelial cells but not on control scaffolds.
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Affiliation(s)
- Loraine L Y Chiu
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, Canada
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Hansen M, Hjortø GM, Met O, Jakobsen MH, Svane IM, Larsen NB. Cell culture plastics with immobilized interleukin-4 for monocyte differentiation. J Biomed Mater Res A 2010; 96:372-83. [PMID: 21171157 DOI: 10.1002/jbm.a.32986] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Revised: 09/22/2010] [Accepted: 09/28/2010] [Indexed: 11/07/2022]
Abstract
Standard cell culture plastic was surface modified by passive adsorption or covalent attachment of interleukin (IL)-4 and investigated for its ability to induce differentiation of human monocytes into mature dendritic cells, a process dose-dependently regulated by IL-4. Covalent attachment of IL-4 proceeded via anthraquinone photochemistry to introduce amine functionalities at the surface followed by coupling of IL-4 through a bifunctional amine-reactive linker. X-ray photoelectron spectroscopy showed that undesirable multilayer formation of the photoactive compound could be avoided by reaction in water instead of phosphate-buffered saline. Passively adsorbed IL-4 was observed to induce differentiation to dendritic cells, but analysis of cell culture supernatants revealed that leakage of IL-4 into solution could account for the differentiation observed. Covalent attachment resulted in bound IL-4 at similar concentrations to the passive adsorption process, as measured by enzyme-linked immunosorbent assays, and the bound IL-4 did not leak into solution to any measurable extent during cell culture. However, covalently bound IL-4 was incapable of inducing monocyte differentiation. This may be caused by IL-4 denaturation or improper epitope presentation induced by the immobilization process, or by biological irresponsiveness of monocytes to IL-4 in immobilized formats.
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Affiliation(s)
- Morten Hansen
- Department of Micro- and Nanotechnology, Technical University of Denmark, DTU-Nanotech, DK-2800 Kongens Lyngby, Denmark
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Chiu LLY, Radisic M. Scaffolds with covalently immobilized VEGF and Angiopoietin-1 for vascularization of engineered tissues. Biomaterials 2010; 31:226-41. [PMID: 19800684 DOI: 10.1016/j.biomaterials.2009.09.039] [Citation(s) in RCA: 207] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2009] [Accepted: 09/07/2009] [Indexed: 11/24/2022]
Abstract
The aim of this study was to engineer a biomaterial capable of supporting vascularization in vitro and in vivo. We covalently immobilized vascular endothelial growth factor (VEGF) and Angiopoietin-1 (Ang1) onto three-dimensional porous collagen scaffolds using 1-ethyl-3-[3-dimethylaminopropyl]carbodiimide hydrochloride (EDC) chemistry. Over both 3 and 7 days in vitro, seeded endothelial cells (ECs) had increased proliferation on scaffolds with immobilized VEGF and/or Ang1 compared to unmodified scaffolds and soluble growth factor controls. Notably, the group with co-immobilized VEGF and Ang1 showed significantly higher cell number (P=0.0079), higher overall lactate production rate (P=0.0044) and higher overall glucose consumption rate (P=0.0034) at Day 3, compared to its corresponding soluble control for which growth factors were added to culture medium. By Day 7, hematoxylin and eosin, live/dead, CD31, and von Willebrand factor staining all showed improved tube formation by ECs when cultivated on scaffolds with co-immobilized growth factors. Interestingly, scaffolds with co-immobilized VEGF and Ang1 showed increased EC infiltration in the chorioallantoic membrane (CAM) assay, compared to scaffolds with independently immobilized VEGF/Ang1. This study presents an alternative method for promoting the formation of vascular structures, via covalent immobilization of angiogenic growth factors that are more stable than soluble ones and have a localized effect.
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Affiliation(s)
- Loraine L Y Chiu
- Department of Chemical Engineering and Applied Chemistry, University of Toronto, 200 College St., Toronto, Ontario M5S 3E5, Canada
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Hjortø GM, Hansen M, Larsen NB, Kledal TN. Generating substrate bound functional chemokine gradients in vitro. Biomaterials 2009; 30:5305-11. [PMID: 19577290 DOI: 10.1016/j.biomaterials.2009.06.018] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2009] [Accepted: 06/11/2009] [Indexed: 11/24/2022]
Abstract
Microcontact printing (mCP) is employed to generate discontinuous microscale gradients of active fractalkine, a chemokine expressed by endothelial cells near sites of inflammation where it is believed to form concentration gradients descending away from the inflamed area. In vivo, fractalkine is a transmembrane molecule extending its chemokine domain into the vascular lumen. Substrate bound in vitro gradients may thus closely resemble in vivo conditions. Direct mCP of sensitive proteins like fractalkine may cause partial protein denaturation and will not ensure correct orientation of the biologically active part of the molecules. Here, indirect mCP of a capture antibody recognizing a molecular tag on the target protein is successfully used to pattern tagged fractalkine in microscale gradient patterns. Fractalkine functions as an adhesion molecule for leukocytes. Cells expressing the fractalkine receptor are found to attach to the gradient structure at a density correlated with the fractional area covered by fractalkine. This indicates that the patterned fractalkine maintains its biological function. The method can be applied to in vitro studies of cell responses to the wide range of naturally surface-bound chemokines (haptotactic gradients). The use of a capture antibody facilitates control of the orientation of tagged molecules, thereby ensuring a high degree of bio-functionality through correct presentation and reduced protein denaturation.
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Affiliation(s)
- Gertrud M Hjortø
- Dept. of Micro- and Nanotechnology, Technical University of Denmark, DTU Nanotech, DK-4000 Roskilde, Denmark.
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Anderson SM, Chen TT, Iruela-Arispe ML, Segura T. The phosphorylation of vascular endothelial growth factor receptor-2 (VEGFR-2) by engineered surfaces with electrostatically or covalently immobilized VEGF. Biomaterials 2009; 30:4618-28. [PMID: 19540581 DOI: 10.1016/j.biomaterials.2009.05.030] [Citation(s) in RCA: 68] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2009] [Accepted: 05/11/2009] [Indexed: 10/20/2022]
Abstract
Growth factors are a class of signaling proteins that direct cell fate through interaction with cell-surface receptors. Although a myriad of possible cell fates stems from a growth factor binding to its receptor, the signaling cascades that result in one fate over another are still being elucidated. One possible mechanism by which nature modulates growth factor signaling is through the method of presentation of the growth factor--soluble or immobilized (matrix bound). Here we present the methodology to study signaling of soluble versus immobilized VEGF through VEGFR-2. We have designed a strategy to covalently immobilize VEGF using its heparin-binding domain to orient the molecule (bind) and a secondary functional group to mediate covalent binding (lock). This bind-and-lock approach aims to allow VEGF to assume a bioactive orientation before covalent immobilization. Surface plasmon resonance (SPR) demonstrated heparin and VEGF binding with surface densities of 60 ng/cm2 and 100 pg/cm2, respectively. ELISA experiments confirmed VEGF surface density and showed that electrostatically bound VEGF releases in cell medium and heparin solutions while covalently bound VEGF remains immobilized. Electrostatically bound VEGF and covalently bound VEGF phosphorylate VEGFR-2 in both VEGFR-2 transfected cells and VEGFR-2 endogenously producing cells. HUVECs plated on VEGF functionalized surfaces showed different morphologies between surface-bound VEGF and soluble VEGF. The surfaces synthesized in these studies allow for the study of VEGF/VEGFR-2 signaling induced by covalently bound, electrostatically bound, and soluble VEGF and may provide further insight into the design of materials for the generation of a mature and stable vasculature.
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Affiliation(s)
- Sean M Anderson
- University of California, Los Angeles, Chemical and Biomolecular Engineering Department, Los Angeles, CA 90095, USA
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10
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Automated microscopic quantification of adipogenic differentiation of human gland stem cells. Ann Anat 2009; 191:13-22. [DOI: 10.1016/j.aanat.2008.09.003] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2008] [Revised: 09/04/2008] [Accepted: 09/09/2008] [Indexed: 02/07/2023]
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