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Shay E, He H, Sakurai S, Tseng SCG. Inhibition of angiogenesis by HC·HA, a complex of hyaluronan and the heavy chain of inter-α-inhibitor, purified from human amniotic membrane. Invest Ophthalmol Vis Sci 2011; 52:2669-78. [PMID: 21228375 DOI: 10.1167/iovs.10-5888] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023] Open
Abstract
PURPOSE To determine whether antiangiogenic action of the amniotic membrane (AM) can be mediated by HC·HA, a covalent complex of hyaluronan (HA) and the heavy chain (HC) of inter-α-inhibitor, purified from AM soluble extract. METHODS HC·HA action on viability, proliferation, attachment, death, migration, and differentiation of human umbilical vein endothelial cells (HUVECs) and neovascularization in chicken chorioallantoic membrane (CAM) was examined by MTT assay, BrdU labeling, cell proliferation assay, cell death detection ELISA, transwell assay, tube formation assay, and CAM assay. RESULTS HC·HA suppressed HUVEC viability more significantly than HA and AM stromal extract, and such suppression was not mediated by CD44. HC·HA also caused HUVECs to become small and rounded, with a decrease in spreading and filamentous actin. Without promoting cell detachment or death, HC·HA dose dependently inhibited proliferation (IC(50), 2.3 μg/mL) and was 100-fold more potent than HA. Migration triggered by VEGF and tube formation was also significantly inhibited by HC·HA. Purified HC·HA did not contain PEDF and TSP-1 but did contain IGFBP-1 and platelet factor 4 while significantly suppressing neovascularization in CAM. CONCLUSIONS The antiangiogenic activity of HC·HA might explain why AM is developmentally avascular and how AM might exert an antiangiogenic action when transplanted to the ocular surface, and it might indicate a potential therapeutic effect of HC·HA in diseases manifesting pathogenic angiogenesis. Roles of IGFBP-1 and platelet factor 4 in HC·HA antiangiogenic action warrant further investigation.
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152
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Dubiel EA, Martin Y, Vermette P. Bridging the Gap Between Physicochemistry and Interpretation Prevalent in Cell−Surface Interactions. Chem Rev 2011; 111:2900-36. [DOI: 10.1021/cr9002598] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Evan A. Dubiel
- Laboratoire de bio-ingénierie et de biophysique de l’Université de Sherbrooke, Department of Chemical and Biotechnological Engineering, Université de Sherbrooke, 2500 Boulevard de l’Université, Sherbrooke, Québec, Canada J1K 2R1
- Research Centre on Aging, Institut universitaire de gériatrie de Sherbrooke, 1036 rue Belvédère Sud, Sherbrooke, Québec, Canada J1H 4C4
| | - Yves Martin
- Laboratoire de bio-ingénierie et de biophysique de l’Université de Sherbrooke, Department of Chemical and Biotechnological Engineering, Université de Sherbrooke, 2500 Boulevard de l’Université, Sherbrooke, Québec, Canada J1K 2R1
- Research Centre on Aging, Institut universitaire de gériatrie de Sherbrooke, 1036 rue Belvédère Sud, Sherbrooke, Québec, Canada J1H 4C4
| | - Patrick Vermette
- Laboratoire de bio-ingénierie et de biophysique de l’Université de Sherbrooke, Department of Chemical and Biotechnological Engineering, Université de Sherbrooke, 2500 Boulevard de l’Université, Sherbrooke, Québec, Canada J1K 2R1
- Research Centre on Aging, Institut universitaire de gériatrie de Sherbrooke, 1036 rue Belvédère Sud, Sherbrooke, Québec, Canada J1H 4C4
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153
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Wijelath E, Namekata M, Murray J, Furuyashiki M, Zhang S, Coan D, Wakao M, Harris RB, Suda Y, Wang L, Sobel M. Multiple mechanisms for exogenous heparin modulation of vascular endothelial growth factor activity. J Cell Biochem 2011; 111:461-8. [PMID: 20524207 DOI: 10.1002/jcb.22727] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Heparin and heparin-like molecules are known to modulate the cellular responses to vascular endothelial growth factor-A (VEGF-A). In this study, we investigated the likely mechanisms for heparin's influence on the biological activity of VEGF-A. Previous studies have shown that exogenous heparin's effects on the biological activity of VEGF-A are many and varied, in part due to the endogenous cell-surface heparan sulfates. To circumvent this problem, we used mutant endothelial cells lacking cell-surface heparan sulfates. We showed that VEGF-induced cellular responses are dependent in part on the presence of the heparan sulfates, and that exogenous heparin significantly augments VEGF's cellular effects especially when endogenous heparan sulfates are absent. Exogenous heparin was also found to play a cross-bridging role between VEGF-A(165) and putative heparin-binding sites within its cognate receptor, VEGFR2 when they were examined in isolation. The cross-bridging appears to be more dependent on molecular weight than on a specific heparin structure. This was confirmed by surface plasmon resonance binding studies using sugar chips immobilized with defined oligosaccharide structures, which showed that VEGF-A(165) binds to a relatively broad range of sulfated glycosaminoglycan structures. Finally, studies of the far-UV circular dichroism spectra of VEGF-A(165) showed that heparin can also modulate the conformation and secondary structure of the protein.
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Affiliation(s)
- Errol Wijelath
- Department of Surgery, Division of Vascular Surgery, VA Puget Sound Health Care System and University of Washington School of Medicine, Seattle, Washington 98108, USA.
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154
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Wijelath E, Kohler TR, Murray J, Namekata M, Yagi M, Sobel M. Enhancement of capillary and cellular ingrowth in ePTFE implants with a proangiogenic recombinant construct derived from fibronectin. J Biomed Mater Res A 2011; 95:641-8. [PMID: 20725965 DOI: 10.1002/jbm.a.32871] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Based on our discoveries of a unique, synergistic interplay between vascular endothelial growth factor (VEGF) and specific domains of the matrix protein fibronectin (FN), we used recombinant technology to create a new protein construct derived from the cell-binding and VEGF-binding domains of FN. We wished to test the hypothesis that this prototype recombinant FN (rFN) protein would enhance cellular and capillary ingrowth in vivo into expanded polytetrafluoroethylene (ePTFE) implants. ePTFE disks of high porosity (60 micron internodal distance) were embedded with fibrin gel and heparin, with/without mixtures of VEGF and rFN and were implanted subcutaneously in rats. Control implants embedded with fibrin glue and heparin alone showed an average of 8.5% (±0.51% standard error mean (SEM)) cellular ingrowth. The addition of either VEGF or rFN caused a modest but significant increase in cellular ingrowth (12.7 ± 1% and 11.8 ± 0.98%, respectively, p < 0.004). However, the combination of rFN/VEGF/heparin dramatically increased cellular ingrowth (27.6 ± 1.62%, p < 0.001), compared with all other treatments. Quantification of capillary ingrowth yielded the same pattern. These results suggest that the incorporation of such biological modulators into cardiovascular implants could offer new strategies for the design of a ready-made small diameter prosthetic graft with enhanced capacity for neovascularization and endothelialization.
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Affiliation(s)
- Errol Wijelath
- Division of Vascular Surgery, Department of Surgery, VA Puget Sound Health Care System, University of Washington School of Medicine, Seattle, Washington, USA.
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155
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Cryan LM, Rogers MS. Targeting the anthrax receptors, TEM-8 and CMG-2, for anti-angiogenic therapy. Front Biosci (Landmark Ed) 2011; 16:1574-88. [PMID: 21196249 DOI: 10.2741/3806] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
The anthrax toxin receptors tumor endothelial marker-8 (TEM-8) and capillary morphogenesis gene-2 (CMG-2) are responsible for allowing entry of anthrax toxin into host cells. These receptors were first discovered due to their enhanced expression on endothelial cells undergoing blood vessel growth or angiogenesis in model systems. Inhibition of angiogenesis is an important strategy for current anti-cancer therapies and treatment of retinal diseases. Functional roles for TEM-8 and CMG-2 in angiogenesis have recently emerged. TEM-8 appears to regulate endothelial cell migration and tubule formation whereas a role for CMG-2 in endothelial proliferation has been documented. TEM-8 and CMG-2 bind differentially to extracellular matrix proteins including collagen I, collagen IV and laminin and these properties may be responsible for their apparent roles in regulating endothelial cell behavior during angiogenesis. TEM-8-binding moieties have also been suggested to be useful in selectively targeting anti-angiogenic and anti-tumorigenic therapies to tumor endothelium. Additionally, studies of modified forms of lethal toxin (LeTx) have demonstrated that targeted inhibition of MAPKs within tumor vessels may represent an efficacious anti-angiogenic strategy.
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Affiliation(s)
- Lorna M Cryan
- Department of Surgery, Children's Hospital Boston, Boston, MA 02115, USA
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156
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Rychly J. Biointerface Technology. Regen Med 2011. [DOI: 10.1007/978-90-481-9075-1_22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022] Open
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157
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Lee JS, Wagoner Johnson AJ, Murphy WL. A modular, hydroxyapatite-binding version of vascular endothelial growth factor. ADVANCED MATERIALS (DEERFIELD BEACH, FLA.) 2010; 22:5494-5498. [PMID: 20941802 DOI: 10.1002/adma.201002970] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Affiliation(s)
- Jae Sung Lee
- Department of Biomedical Engineering, University of Wisconsin, Madison, 53706, USA
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158
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Cseh B, Fernandez-Sauze S, Grall D, Schaub S, Doma E, Van Obberghen-Schilling E. Autocrine fibronectin directs matrix assembly and crosstalk between cell–matrix and cell–cell adhesion in vascular endothelial cells. J Cell Sci 2010; 123:3989-99. [DOI: 10.1242/jcs.073346] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
Cellular fibronectin (cFN) variants harboring extra FN type 3 repeats, namely extra domains B and A, are major constituents of the extracellular matrix around newly forming blood vessels during development and angiogenesis. Their expression is induced by angiogenic stimuli and their assembly into fibrillar arrays is driven by cell-generated tension at α5β1 integrin-based adhesions. Here, we examined the role and functional redundancy of cFN variants in cultured endothelial cells by isoform-selective RNA interference. We show that FN fibrillogenesis is a cell-autonomous process whereby basally directed secretion and assembly of cellular FN are tightly coupled events that play an important role not only in signaling at cell–matrix adhesions but also at cell–cell contacts. Silencing of cFN variants differentially affects integrin usage, cell spreading, motility and capillary morphogenesis in vitro. cFN-deficient cells undergo a switch from α5β1- to αvβ3-based adhesion, accompanied by a Src-regulated disruption of adherens junctions. These studies identify a crucial role for autocrine FN in subendothelial matrix assembly and junctional integrity that provides spatially and temporally restricted control of endothelial plasticity during angiogenic blood vessel remodeling.
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Affiliation(s)
- Botond Cseh
- University of Nice-Sophia Antipolis, CNRS UMR 6543, Centre Antoine Lacassagne, 33 Avenue de Valombrose, 06189 Nice, France
| | - Samantha Fernandez-Sauze
- University of Nice-Sophia Antipolis, CNRS UMR 6543, Centre Antoine Lacassagne, 33 Avenue de Valombrose, 06189 Nice, France
| | - Dominique Grall
- University of Nice-Sophia Antipolis, CNRS UMR 6543, Centre Antoine Lacassagne, 33 Avenue de Valombrose, 06189 Nice, France
| | - Sébastien Schaub
- University of Nice-Sophia Antipolis, CNRS UMR 6543, Centre Antoine Lacassagne, 33 Avenue de Valombrose, 06189 Nice, France
| | - Eszter Doma
- University of Nice-Sophia Antipolis, CNRS UMR 6543, Centre Antoine Lacassagne, 33 Avenue de Valombrose, 06189 Nice, France
| | - Ellen Van Obberghen-Schilling
- University of Nice-Sophia Antipolis, CNRS UMR 6543, Centre Antoine Lacassagne, 33 Avenue de Valombrose, 06189 Nice, France
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159
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Yun YR, Won JE, Jeon E, Lee S, Kang W, Jo H, Jang JH, Shin US, Kim HW. Fibroblast growth factors: biology, function, and application for tissue regeneration. J Tissue Eng 2010; 2010:218142. [PMID: 21350642 PMCID: PMC3042641 DOI: 10.4061/2010/218142] [Citation(s) in RCA: 392] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2010] [Accepted: 10/06/2010] [Indexed: 12/12/2022] Open
Abstract
Fibroblast growth factors (FGFs) that signal through FGF receptors (FGFRs) regulate a broad spectrum of biological functions, including cellular proliferation, survival, migration, and differentiation. The FGF signal pathways are the RAS/MAP kinase pathway, PI3 kinase/AKT pathway, and PLCγ pathway, among which the RAS/MAP kinase pathway is known to be predominant. Several studies have recently implicated the in vitro biological functions of FGFs for tissue regeneration. However, to obtain optimal outcomes in vivo, it is important to enhance the half-life of FGFs and their biological stability. Future applications of FGFs are expected when the biological functions of FGFs are potentiated through the appropriate use of delivery systems and scaffolds. This review will introduce the biology and cellular functions of FGFs and deal with the biomaterials based delivery systems and their current applications for the regeneration of tissues, including skin, blood vessel, muscle, adipose, tendon/ligament, cartilage, bone, tooth, and nerve tissues.
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Affiliation(s)
- Ye-Rang Yun
- Institute of Tissue Regeneration Engineering (ITREN), Dankook University, Cheonan 330-714, Republic of Korea
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160
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Fibronectin growth factor-binding domains are required for fibroblast survival. J Invest Dermatol 2010; 131:84-98. [PMID: 20811396 DOI: 10.1038/jid.2010.253] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Fibronectin (FN) is required for embryogenesis, morphogenesis, and wound repair, and its Arg-Gly-Asp-containing central cell-binding domain (CCBD) is essential for mesenchymal cell survival and growth. Here, we demonstrate that FN contains three growth factor-binding domains (FN-GFBDs) that bind platelet-derived growth factor-BB (PDGF-BB), a potent fibroblast survival and mitogenic factor. These sites bind PDGF-BB with dissociation constants of 10-100 nM. FN-null cells cultured on recombinant CCBD (FNIII(8-11)) without a FN-GFBD demonstrated minimal metabolism and underwent autophagy at 24 hours, followed by apoptosis at 72 hours, even in the presence of PDGF-BB. In contrast, FN-null cells plated on FNIII(8-11) contiguous with FN-GFBD survived without, and proliferated with, PDGF-BB. FN-null cell survival on FNIII(8-11) and noncontiguous arrays of FN-GFBDs required these domains to be adsorbed on the same surface, suggesting the existence of a mesenchymal cell-extracellular matrix synapse. Thus, fibroblast survival required GF stimulation in the presence of a FN-GFBD, as well as adhesion to FN through the CCBD. The findings that fibroblast survival is dependent on FN-GFBD underscore the critical importance of pericellular matrix for cell survival and have significant implications for cutaneous wound healing and regeneration.
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161
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Collier JH, Rudra JS, Gasiorowski JZ, Jung JP. Multi-component extracellular matrices based on peptide self-assembly. Chem Soc Rev 2010; 39:3413-24. [PMID: 20603663 PMCID: PMC3387682 DOI: 10.1039/b914337h] [Citation(s) in RCA: 175] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Extracellular matrices (ECMs) are challenging design targets for materials synthesis because they serve multiple biological roles, and they are composed of multiple molecular constituents. In addition, their composition and activities are dynamic and variable between tissues, and they are difficult to study mechanistically in physiological contexts. Nevertheless, the design of synthetic ECMs is a central consideration in applications such as regenerative medicine and 3D cell culture. In order to produce synthetic matrices having both multi-component construction and high levels of compositional definition, strategies based on molecular self-assembly are receiving increasing interest. These approaches are described in this tutorial review and compared with the structures and processes in native ECMs that serve as their inspiration.
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Affiliation(s)
- Joel H Collier
- Department of Surgery, University of Chicago, 5841 S. Maryland Ave., MC 5032, Chicago, IL 60637, USA.
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162
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Rasala BA, Muto M, Lee PA, Jager M, Cardoso RMF, Behnke CA, Kirk P, Hokanson CA, Crea R, Mendez M, Mayfield SP. Production of therapeutic proteins in algae, analysis of expression of seven human proteins in the chloroplast of Chlamydomonas reinhardtii. PLANT BIOTECHNOLOGY JOURNAL 2010; 8:719-33. [PMID: 20230484 PMCID: PMC2918638 DOI: 10.1111/j.1467-7652.2010.00503.x] [Citation(s) in RCA: 162] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/19/2023]
Abstract
Recombinant proteins are widely used today in many industries, including the biopharmaceutical industry, and can be expressed in bacteria, yeasts, mammalian and insect cell cultures, or in transgenic plants and animals. In addition, transgenic algae have also been shown to support recombinant protein expression, both from the nuclear and chloroplast genomes. However, to date, there are only a few reports on recombinant proteins expressed in the algal chloroplast. It is unclear whether this is because of few attempts or of limitations of the system that preclude expression of many proteins. Thus, we sought to assess the versatility of transgenic algae as a recombinant protein production platform. To do this, we tested whether the algal chloroplast could support the expression of a diverse set of current or potential human therapeutic proteins. Of the seven proteins chosen, >50% expressed at levels sufficient for commercial production. Three expressed at 2%-3% of total soluble protein, while a forth protein accumulated to similar levels when translationally fused to a well-expressed serum amyloid protein. All of the algal chloroplast-expressed proteins are soluble and showed biological activity comparable to that of the same proteins expressed using traditional production platforms. Thus, the success rate, expression levels, and bioactivity achieved demonstrate the utility of Chlamydomonas reinhardtii as a robust platform for human therapeutic protein production.
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Affiliation(s)
- Beth A Rasala
- Department of Cell Biology and the Skaggs Institute for Chemical Biology, 10550 N. Torrey Pines Rd, La Jolla, CA92037, USA
| | - Machiko Muto
- Department of Cell Biology and the Skaggs Institute for Chemical Biology, 10550 N. Torrey Pines Rd, La Jolla, CA92037, USA
| | - Philip A Lee
- Department of Cell Biology and the Skaggs Institute for Chemical Biology, 10550 N. Torrey Pines Rd, La Jolla, CA92037, USA
| | - Michal Jager
- Department of Cell Biology and the Skaggs Institute for Chemical Biology, 10550 N. Torrey Pines Rd, La Jolla, CA92037, USA
| | | | - Craig A Behnke
- Sapphire Energy, 3115 Merryfield Rd., San Diego, CA 92121
| | - Peter Kirk
- Protelica, 26118 Research Pl, Hayward, CA 94545
| | | | | | - Michael Mendez
- Sapphire Energy, 3115 Merryfield Rd., San Diego, CA 92121
| | - Stephen P Mayfield
- Department of Cell Biology and the Skaggs Institute for Chemical Biology, 10550 N. Torrey Pines Rd, La Jolla, CA92037, USA
- Corresponding author: SPM:
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163
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Martino MM, Hubbell JA. The 12th–14th type III repeats of fibronectin function as a highly promiscuous growth factor‐binding domain. FASEB J 2010. [DOI: 10.1096/fj.09.151282] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
| | - Jeffrey A. Hubbell
- Institute of Bioengineering Lausanne Switzerland
- Institute of Chemical Sciences and EngineeringEcole Polytechnique Fédérale de Lausanne Lausanne Switzerland
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164
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Martino MM, Hubbell JA. The 12th-14th type III repeats of fibronectin function as a highly promiscuous growth factor-binding domain. FASEB J 2010; 24:4711-21. [PMID: 20671107 DOI: 10.1096/fj.09-151282] [Citation(s) in RCA: 216] [Impact Index Per Article: 15.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
It has recently been shown that some growth factors (GFs) have strong interactions with nonproteoglycan extracellular matrix proteins. Relevant here, the 12th-14th type three repeats of fibronectin (FN III12-14) have been shown to bind insulin-like growth factor binding-protein-3, fibroblast growth factor (FGF)-2, and vascular endothelial growth factor (VEGF)-A with high affinity. Since FN III12-14 is known to bind GFs from different families, we hypothesized that this domain could be highly promiscuous in its GF-binding capacity. We used biochemical approaches and surface plasmon resonance to investigate such interactions with recombinant FN III12-14. We found that FN III12-14 binds most of the GFs from the platelet-derived growth factor (PDGF)/VEGF and FGF families and some GFs from the transforming growth factor-β and neurotrophin families, with K(D) values in the nanomolar range, without inhibiting GF activity. Overall, 25 new binding interactions were identified. In a clinically relevant fibrin matrix, a fibrin-binding variant of FN III12-14 was highly effective as a GF delivery system. For instance, in matrices functionalized with FN III12-14, PDGF-BB-induced sprouting of human smooth muscle cell spheroids was greatly enhanced. We show that FN III12-14 is a highly promiscuous ligand for GFs and also holds great potential in clinical healing applications.
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Affiliation(s)
- Mikaël M Martino
- Institute of Bioengineering, Ecole Polytechnique Fédérale de Lausanne, Lausanne, Switzerland
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165
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Hauck SM, Dietter J, Kramer RL, Hofmaier F, Zipplies JK, Amann B, Feuchtinger A, Deeg CA, Ueffing M. Deciphering membrane-associated molecular processes in target tissue of autoimmune uveitis by label-free quantitative mass spectrometry. Mol Cell Proteomics 2010; 9:2292-305. [PMID: 20601722 DOI: 10.1074/mcp.m110.001073] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Autoimmune uveitis is a blinding disease presenting with autoantibodies against eye-specific proteins as well as autoagressive T cells invading and attacking the immune-privileged target tissue retina. The molecular events enabling T cells to invade and attack the tissue have remained elusive. Changes in membrane protein expression patterns between diseased and healthy stages are especially interesting because initiating events of disease will most likely occur at membranes. Since disease progression is accompanied with a break-down of the blood-retinal barrier, serum-derived proteins mask the potential target tissue-related changes. To overcome this limitation, we used membrane-enriched fractions derived from retinas of the only available spontaneous animal model for the disease equine recurrent uveitis, and compared expression levels by a label-free LC-MSMS-based strategy to healthy control samples. We could readily identify a total of 893 equine proteins with 57% attributed to the Gene Ontology project term "membrane." Of these, 179 proteins were found differentially expressed in equine recurrent uveitis tissue. Pathway enrichment analyses indicated an increase in proteins related to antigen processing and presentation, TNF receptor signaling, integrin cell surface interactions and focal adhesions. Additionally, loss of retina-specific proteins reflecting decrease of vision was observed as well as an increase in Müller glial cell-specific proteins indicating glial reactivity. Selected protein candidates (caveolin 1, integrin alpha 1 and focal adhesion kinase) were validated by immunohistochemistry and tissue staining pattern pointed to a significant increase of these proteins at the level of the outer limiting membrane which is part of the outer blood-retinal barrier. Taken together, the membrane enrichment in combination with LC-MSMS-based label-free quantification greatly increased the sensitivity of the comparative tissue profiling and resulted in detection of novel molecular pathways related to equine recurrent uveitis.
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Affiliation(s)
- Stefanie M Hauck
- Department of Protein Science, Helmholtz Zentrum Mùnchen - German Research Center for Environmental Health, Neuherberg, Germany.
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166
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Dummula K, Vinukonda G, Xu H, Hu F, Zia MT, Braun A, Shi Q, Wolk J, Ballabh P. Development of integrins in the vasculature of germinal matrix, cerebral cortex, and white matter of fetuses and premature infants. J Neurosci Res 2010; 88:1193-204. [PMID: 19960540 DOI: 10.1002/jnr.22301] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Germinal matrix (GM) vasculature is selectively vulnerable to hemorrhage in premature infants during the first 48 hr of life. This is attributed to rapid angiogenesis of this brain region, resulting in formation of nascent vessels that show a paucity of pericytes and immaturity of extracellular matrix. Integrins are key regulators of angiogenesis and contribute to stabilization of cerebral vasculature by providing endothelial- and astrocyte-matrix adhesion. Therefore, we asked whether GM exhibited a distinct regional pattern of integrin expression that was dissimilar from that of the cerebral cortex and white matter in human fetuses and premature infants. To this end, we measured protein and gene expression of integrins in the GM, cortex, and white matter of human fetuses (15-22 weeks), premature infants (23-35 weeks), and mature infants (36-40 weeks). We found that protein levels of alpha5beta1 integrin were greater in the GM than in the cortex or white matter by 1.6-fold for both fetuses and premature infants. alpha5beta1 integrin mRNA expression was higher in the GM than in the cortex or white matter by 2-fold for fetuses but not for premature infants. alphaVbeta3, alphaVbeta5, alphaVbeta8, and alpha4beta1 integrin expression were comparable among GM, cortex, and white matter in fetuses and premature infants. Because alpha5beta1 integrin is a central regulator of angiogenesis, its elevation in the GM of fetuses and premature infants indicates that this might be a key activator of endothelial proliferation in this brain region. We speculate that selective alpha5beta1 integrin inhibition might suppress angiogenesis in the GM and thus prevent brain hemorrhage in premature infants.
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Affiliation(s)
- Krishna Dummula
- Department of Pediatrics, New York Medical College-Westchester Medical Center, Valhalla, New York, USA
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167
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Abstract
Pref-1/Dlk1 is made as an epidermal growth factor (EGF) repeat-containing transmembrane protein but is cleaved by tumor necrosis factor alpha converting enzyme (TACE) to generate a biologically active soluble form. Soluble Pref-1 inhibits adipocyte differentiation through the activation of extracellular signal-regulated kinase/mitogen-activated protein kinase (ERK/MAPK) and the subsequent upregulation of Sox9 expression. However, others have implicated Notch in Pref-1 signaling and function. Here, we show that Pref-1 does not interact with, or require, Notch for its function. Instead, we show a direct interaction of Pref-1 and fibronectin via the Pref-1 juxtamembrane domain and fibronectin C-terminal domain. We also show that fibronectin is required for the Pref-1-mediated inhibition of adipocyte differentiation, the activation of ERK/MAPK, and the upregulation of Sox9. Furthermore, disrupting fibronectin binding to integrin by the addition of RGD peptides or by the knockdown of alpha 5 integrin prevents the Pref-1 inhibition of adipocyte differentiation. Pref-1 activates the integrin downstream signaling molecules, FAK and Rac, and ERK activation by Pref-1 is blunted by the knockdown of Rac or by the forced expression of dominant-negative Rac. We conclude that, by interacting with fibronectin, Pref-1 activates integrin downstream signaling to activate MEK/ERK and to inhibit adipocyte differentiation.
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168
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Wu FTH, Stefanini MO, Mac Gabhann F, Kontos CD, Annex BH, Popel AS. VEGF and soluble VEGF receptor-1 (sFlt-1) distributions in peripheral arterial disease: an in silico model. Am J Physiol Heart Circ Physiol 2010; 298:H2174-91. [PMID: 20382861 DOI: 10.1152/ajpheart.00365.2009] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Vascular endothelial growth factor (VEGF) is a key regulator of angiogenesis, the growth of new capillaries from existing microvasculature. In peripheral arterial disease (PAD), lower extremity muscle ischemia develops downstream of atherosclerotic obstruction. A working hypothesis proposed that the maladaptive overexpression of soluble VEGF receptor 1 (sVEGFR1) in ischemic muscle tissues, and its subsequent antagonism of VEGF bioactivity, may contribute to the deficient angiogenic response in PAD, as well as the limited success of therapeutic angiogenesis strategies where exogenous VEGF genes/proteins are delivered. The objectives of this study were to develop a computational framework for simulating the systemic distributions of VEGF and sVEGFR1 (e.g., intramuscular vs. circulating, free vs. complexed) as observed in human PAD patients and to serve as a platform for the systematic optimization of diagnostic tools and therapeutic strategies. A three-compartment model was constructed, dividing the human body into the ischemic calf muscle, blood, and the rest of the body, connected through macromolecular biotransport processes. Detailed molecular interactions between VEGF, sVEGFR1, endothelial surface receptors (VEGFR1, VEGFR2, NRP1), and interstitial matrix sites were modeled. Our simulation results did not support a simultaneous decrease in plasma sVEGFR1 during PAD-associated elevations in plasma VEGF reported in literature. Furthermore, despite the overexpression in sVEGFR1, our PAD control demonstrated increased proangiogenic signaling complex formation, relative to our previous healthy control, due to sizeable upregulations in VEGFR2 and VEGF expression, thus leaving open the possibility that impaired angiogenesis in PAD may be rooted in signaling pathway disruptions downstream of ligand-receptor binding.
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Affiliation(s)
- Florence T H Wu
- Dept. of Biomedical Engineering, Johns Hopkins Univ. School of Medicine, 720 Rutland Ave., 613 Traylor Research Bldg., Baltimore, MD 21205, USA.
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169
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Eckes B, Nischt R, Krieg T. Cell-matrix interactions in dermal repair and scarring. FIBROGENESIS & TISSUE REPAIR 2010; 3:4. [PMID: 20222960 PMCID: PMC2855519 DOI: 10.1186/1755-1536-3-4] [Citation(s) in RCA: 125] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/07/2009] [Accepted: 03/11/2010] [Indexed: 12/14/2022]
Abstract
Regulation of cellular functions during dermal repair following injury is complex and critically dependent on the interaction of cells with the surrounding extracellular matrix (ECM). The ECM comprises various families of macromolecules that form the structural scaffold of the tissue, but also carry distinct biological activities. After injury to the skin, the defect is filled by a provisional matrix that is invaded by inflammatory cells, sprouting blood vessels and fibroblasts. In a later phase, the wound contracts, the tissue is replaced by mature connective tissue produced by activated fibroblasts, and a scar is formed. All cells involved communicate directly with the ECM by integrins and other matrix receptors. These transmit signals and induce adaptive responses to the environment by the embedded cells. The ECM or proteolytic fragments of individual ECM constituents exert defined biological activities influencing cell survival, differentiation of myofibroblasts, ECM synthesis and turnover, wound angiogenesis and scar remodeling. Extensive crosstalk exists between ECM and growth factors, and between growth factors and integrins. ECM-cell contact also enables direct transmission of mechanical tension, which then modulates many activities of all cellular players. Understanding this complex interplay is important to provide a basis for designing effective wound therapy and for strategic interference with mechanisms that have gone out of control in fibrotic conditions.
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Affiliation(s)
- Beate Eckes
- Department of Dermatology, University of Cologne, Cologne, Germany.
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170
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Smith EM, Mitsi M, Nugent MA, Symes K. PDGF-A interactions with fibronectin reveal a critical role for heparan sulfate in directed cell migration during Xenopus gastrulation. Proc Natl Acad Sci U S A 2009; 106:21683-8. [PMID: 19966216 PMCID: PMC2799789 DOI: 10.1073/pnas.0902510106] [Citation(s) in RCA: 51] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2009] [Indexed: 12/18/2022] Open
Abstract
Platelet-derived growth factor (PDGF) signaling is essential for processes involving cell motility and differentiation during embryonic development in a wide variety of organisms including the mouse, frog, zebrafish, and sea urchin. In early Xenopus laevis embryos, PDGF-AA provides guidance cues for the migration of anterior mesendoderm cells as they move across a fibronectin-rich extracellular matrix. The long form of PDGF-A includes a positively charged carboxyl-terminal retention motif that can interact with the extracellular matrix and heparan sulfate proteoglycans (HSPGs). In this study we demonstrate that PDGF-AA binds directly to fibronectin and that this association is greatly enhanced by heparin. The PDGF-AA-fibronectin binding occurs across a broad range of pHs (5.5-9), which is significant because the PDGF-guided migration of Xenopus mesendoderm cells occurs under basic extracellular conditions (pH 8.4). We further demonstrate that endogenous HSPG's are required for the PDGF-AA-guided mesendoderm movement, suggesting an in vivo role for HSPGs in mediating the interaction between PDGF-AA and fibronectin.
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Affiliation(s)
- Erin M. Smith
- Department of Biochemistry, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118; and
| | - Maria Mitsi
- Department of Biochemistry, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118; and
- Institute of Biologically Oriented Materials, Eidgenössische Technische Hochschule Zürich, Wolfgang-Pauli-Strasse 10, HCI F443 (Hönggerberg), CH-8093 Zürich, Switzerland
| | - Matthew A. Nugent
- Department of Biochemistry, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118; and
| | - Karen Symes
- Department of Biochemistry, Boston University School of Medicine, 72 East Concord Street, Boston, MA 02118; and
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171
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Daugherty AL, Mrsny RJ. Local tissue distribution and cellular fate of vascular endothelial growth factor (VEGF) following intramuscular injection. J Drug Target 2009; 18:27-35. [DOI: 10.3109/10611860903134317] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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172
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Abstract
The extracellular matrix (ECM) and ECM proteins are important in phenomena as diverse as developmental patterning, stem cell niches, cancer, and genetic diseases. The ECM has many effects beyond providing structural support. ECM proteins typically include multiple, independently folded domains whose sequences and arrangement are highly conserved. Some of these domains bind adhesion receptors such as integrins that mediate cell-matrix adhesion and also transduce signals into cells. However, ECM proteins also bind soluble growth factors and regulate their distribution, activation, and presentation to cells. As organized, solid-phase ligands, ECM proteins can integrate complex, multivalent signals to cells in a spatially patterned and regulated fashion. These properties need to be incorporated into considerations of the functions of the ECM.
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Affiliation(s)
- Richard O Hynes
- Howard Hughes Medical Institute, David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA.
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173
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Affiliation(s)
- Richard O. Hynes
- Howard Hughes Medical Institute, David H. Koch Institute for Integrative Cancer Research, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
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174
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Wu FTH, Stefanini MO, Mac Gabhann F, Kontos CD, Annex BH, Popel AS. A systems biology perspective on sVEGFR1: its biological function, pathogenic role and therapeutic use. J Cell Mol Med 2009; 14:528-52. [PMID: 19840194 PMCID: PMC3039304 DOI: 10.1111/j.1582-4934.2009.00941.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Angiogenesis is the growth of new capillaries from pre-existent microvasculature. A wide range of pathological conditions, from atherosclerosis to cancer, can be attributed to either excessive or deficient angiogenesis. Central to the physiological regulation of angiogenesis is the vascular endothelial growth factor (VEGF) system – its ligands and receptors (VEGFRs) are thus prime molecular targets of pro-angiogenic and anti-angiogenic therapies. Of growing interest as a prognostic marker and therapeutic target in angiogenesis-dependent diseases is soluble VEGF receptor-1 (sVEGFR1, also known as sFlt-1) – a truncated version of the cell membrane-spanning VEGFR1. For instance, it is known that sVEGFR1 is involved in the endothelial dysfunction characterizing the pregnancy disorder of pre-eclampsia, and sVEGFR1’s therapeutic potential as an anti-angiogenic agent is being evaluated in pre-clinical models of cancer. This mini review begins with an examination of the protein domain structure and biomolecular interactions of sVEGFR1 in relation to the full-length VEGFR1. A synopsis of known and inferred physiological and pathological roles of sVEGFR1 is then given, with emphasis on the utility of computational systems biology models in deciphering the molecular mechanisms by which sVEGFR1’s purported biological functions occur. Finally, we present the need for a systems biology perspective in interpreting circulating VEGF and sVEGFR1 concentrations as surrogate markers of angiogenic status in angiogenesis-dependent diseases.
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Affiliation(s)
- Florence T H Wu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
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175
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Pericyte recruitment during vasculogenic tube assembly stimulates endothelial basement membrane matrix formation. Blood 2009; 114:5091-101. [PMID: 19822899 DOI: 10.1182/blood-2009-05-222364] [Citation(s) in RCA: 407] [Impact Index Per Article: 27.1] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/04/2023] Open
Abstract
We show that endothelial cell (EC)-generated vascular guidance tunnels (ie, matrix spaces created during tube formation) serve as conduits for the recruitment and motility of pericytes along EC ablumenal surfaces to facilitate vessel maturation events, including vascular basement membrane matrix assembly and restriction of EC tube diameter. During quail development, pericyte recruitment along microvascular tubes directly correlates with vascular basement membrane matrix deposition. Pericyte recruitment to EC tubes leads to specific induction of fibronectin and nidogen-1 (ie, matrix-bridging proteins that link together basement membrane components) as well as perlecan and laminin isoforms. Coincident with these events, up-regulation of integrins, alpha(5)beta(1), alpha(3)beta(1), alpha(6)beta(1), and alpha(1)beta(1), which bind fibronectin, nidogens, laminin isoforms, and collagen type IV, occurs in EC-pericyte cocultures, but not EC-only cultures. Integrin-blocking antibodies to these receptors, disruption of fibronectin matrix assembly, and small interfering RNA suppression of pericyte tissue inhibitor of metalloproteinase (TIMP)-3 (a known regulator of vascular tube stabilization) all lead to decreased EC basement membrane, resulting in increased vessel lumen diameter, a key indicator of dysfunctional EC-pericyte interactions. Thus, pericyte recruitment to EC-lined tubes during vasculogenesis is a stimulatory event controlling vascular basement membrane matrix assembly, a fundamental maturation step regulating the transition from vascular morphogenesis to stabilization.
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176
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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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177
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Papakonstantinou E, Karakiulakis G. The 'sweet' and 'bitter' involvement of glycosaminoglycans in lung diseases: pharmacotherapeutic relevance. Br J Pharmacol 2009; 157:1111-27. [PMID: 19508395 DOI: 10.1111/j.1476-5381.2009.00279.x] [Citation(s) in RCA: 58] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The extracellular matrix (ECM) plays a significant role in the structure and function of the lung. The ECM is a three-dimensional fibre mesh, comprised of various interconnected and intercalated macromolecules, among which are the glycosaminoglycans (GAG). GAG are long, linear and highly charged, heterogeneous polysaccharides that are composed of a variable number of repeating disaccharide units (macromolecular sugars) and most of them, as their name implies, have a sweet taste. In the lung, GAG support the structure of the interstitium, the subepithelial tissue and the bronchial walls, and are secreted in the airway secretions. Besides maintaining lung tissue structure, GAG also play an important role in lung function as they regulate hydration and water homeostasis, modulate the inflammatory response and influence lung tissue repair and remodelling. However, depending on their size and/or degree of sulphation, and their immobilization or solubilization in the ECM, specific GAG in the lung either live up to their sweet taste/name, supporting normal lung physiology, or they are associated to 'bitter' effects, related to lung pathology. The present review discusses the biological role of GAG in the lung as well as the involvement of these molecules in various respiratory diseases. Given the great structural diversity of GAG, understanding the changes in GAG expression that occur in lung diseases may lead to novel targets for pharmacological intervention in order to prevent and/or to treat a range of lung diseases.
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Affiliation(s)
- Eleni Papakonstantinou
- 2nd Department of Pharmacology, School of Medicine, Aristotle University of Thessaloniki, Thessaloniki, Greece.
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178
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Sabatino M, Kim-Schulze S, Panelli MC, Stroncek D, Wang E, Taback B, Kim DW, Deraffele G, Pos Z, Marincola FM, Kaufman HL. Serum vascular endothelial growth factor and fibronectin predict clinical response to high-dose interleukin-2 therapy. J Clin Oncol 2009; 27:2645-52. [PMID: 19364969 DOI: 10.1200/jco.2008.19.1106] [Citation(s) in RCA: 147] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
PURPOSE High-dose interleukin-2 (IL-2) induces durable therapeutic responses in a small subset of patients with metastatic melanoma and renal cell carcinoma, but simple pretreatment predictors of response have not been identified. PATIENTS AND METHODS To identify predictive biomarkers of clinical response, sera from patients treated with high-dose IL-2 were collected for analysis using a customized, multiplex antibody-targeted protein array platform that surveyed expression of soluble factors associated with tumor immunobiology. Soluble factors associated with clinical responses were analyzed using a multivariate permutation test, and survival outcomes were determined using Kaplan-Meier and log-rank tests. RESULTS A training set from 10 patients identified 68 potentially relevant soluble factors that were then tested in an independent validation set of 49 patients. Class comparison revealed a cluster of 11 biomarkers that were associated with therapeutic outcome. Vascular endothelial growth factor (VEGF) and fibronectin were identified as independent predictors of response. In particular, high levels of these proteins were correlated with lack of clinical response and decreased overall survival. CONCLUSION Serum VEGF and fibronectin are easily measured pretreatment biomarkers that could serve to exclude patients unlikely to respond to IL-2 therapy.
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Affiliation(s)
- Marianna Sabatino
- Infectious Disease and Immunogenetics Section, Department of Transfusion Medicine, Warren G Magnuson Clinical Center, NIH, Bethesda, MD, USA
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179
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Wu FTH, Stefanini MO, Mac Gabhann F, Popel AS. A compartment model of VEGF distribution in humans in the presence of soluble VEGF receptor-1 acting as a ligand trap. PLoS One 2009; 4:e5108. [PMID: 19352513 PMCID: PMC2663039 DOI: 10.1371/journal.pone.0005108] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2008] [Accepted: 03/10/2009] [Indexed: 12/25/2022] Open
Abstract
Vascular endothelial growth factor (VEGF), through its activation of cell surface receptor tyrosine kinases including VEGFR1 and VEGFR2, is a vital regulator of stimulatory and inhibitory processes that keep angiogenesis--new capillary growth from existing microvasculature--at a dynamic balance in normal physiology. Soluble VEGF receptor-1 (sVEGFR1)--a naturally-occurring truncated version of VEGFR1 lacking the transmembrane and intracellular signaling domains--has been postulated to exert inhibitory effects on angiogenic signaling via two mechanisms: direct sequestration of angiogenic ligands such as VEGF; or dominant-negative heterodimerization with surface VEGFRs. In pre-clinical studies, sVEGFR1 gene and protein therapy have demonstrated efficacy in inhibiting tumor angiogenesis; while in clinical studies, sVEGFR1 has shown utility as a diagnostic or prognostic marker in a widening array of angiogenesis-dependent diseases. Here we developed a novel computational multi-tissue model for recapitulating the dynamic systemic distributions of VEGF and sVEGFR1. Model features included: physiologically-based multi-scale compartmentalization of the human body; inter-compartmental macromolecular biotransport processes (vascular permeability, lymphatic drainage); and molecularly-detailed binding interactions between the ligand isoforms VEGF(121) and VEGF(165), signaling receptors VEGFR1 and VEGFR2, non-signaling co-receptor neuropilin-1 (NRP1), as well as sVEGFR1. The model was parameterized to represent a healthy human subject, whereupon we investigated the effects of sVEGFR1 on the distribution and activation of VEGF ligands and receptors. We assessed the healthy baseline stability of circulating VEGF and sVEGFR1 levels in plasma, as well as their reliability in indicating tissue-level angiogenic signaling potential. Unexpectedly, simulated results showed that sVEGFR1 - acting as a diffusible VEGF sink alone, i.e., without sVEGFR1-VEGFR heterodimerization--did not significantly lower interstitial VEGF, nor inhibit signaling potential in tissues. Additionally, the sensitivity of plasma VEGF and sVEGFR1 to physiological fluctuations in transport rates may partially account for the heterogeneity in clinical measurements of these circulating angiogenic markers, potentially hindering their diagnostic reliability for diseases.
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Affiliation(s)
- Florence T H Wu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, United States of America.
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180
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Somanath PR, Malinin NL, Byzova TV. Cooperation between integrin alphavbeta3 and VEGFR2 in angiogenesis. Angiogenesis 2009; 12:177-85. [PMID: 19267251 DOI: 10.1007/s10456-009-9141-9] [Citation(s) in RCA: 188] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/07/2009] [Accepted: 02/16/2009] [Indexed: 11/30/2022]
Abstract
The cross-talk between receptor tyrosine kinases and integrin receptors are known to be crucial for a number of cellular functions. On endothelial cells, an interaction between integrin alphavbeta3 and VEGFR2 seems to be particularly important process during vascularization. Importantly, the functional association between VEGFR2 and integrin alphavbeta3 is of reciprocal nature since each receptor is able to promote activation of its counterpart. This mutually beneficial relationship regulates a number of cellular activities involved in angiogenesis, including endothelial cell migration, survival and tube formation, and hematopoietic cell functions within vasculature. This article discusses several possible mechanisms reported by different labs which mediate formation of the complex between VEGFR-2 and alphavbeta3 on endothelial cells. The pathological consequences and regulatory events involved in this receptor cross-talk are also presented.
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Affiliation(s)
- Payaningal R Somanath
- Joseph J. Jacobs Center for Thrombosis and Vascular Biology, Department of Molecular Cardiology, NB50, Lerner Research Institute, The Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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181
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Astrof S, Hynes RO. Fibronectins in vascular morphogenesis. Angiogenesis 2009; 12:165-75. [PMID: 19219555 DOI: 10.1007/s10456-009-9136-6] [Citation(s) in RCA: 186] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2009] [Accepted: 01/30/2009] [Indexed: 11/28/2022]
Abstract
Fibronectin is an extracellular matrix protein found only in vertebrate organisms containing endothelium-lined vasculature and is required for cardiovascular development in fish and mice. Fibronectin and its splice variants containing EIIIA and EIIIB domains are highly upregulated around newly developing vasculature during embryogenesis and in pathological conditions including atherosclerosis, cardiac hypertrophy, and tumorigenesis. However, their molecular roles in these processes are not entirely understood. We review genetic studies examining functions of fibronectin and its splice variants during embryonic cardiovascular development, and discuss potential roles of fibronectin in vascular disease and tumor angiogenesis.
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Affiliation(s)
- Sophie Astrof
- Greenberg Division of Cardiology, Department of Medicine, Weill Medical College of Cornell University, New York, NY 10065, USA.
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182
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Ambesi A, McKeown-Longo PJ. Anastellin, the angiostatic fibronectin peptide, is a selective inhibitor of lysophospholipid signaling. Mol Cancer Res 2009; 7:255-65. [PMID: 19208746 DOI: 10.1158/1541-7786.mcr-08-0195] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Angiogenesis is regulated by integrin-dependent cell adhesion and the activation of specific cell surface receptors on vascular endothelial cells by angiogenic factors. Lysophosphatidic acid (LPA) and sphingosine-1 phosphate (S1P) are bioactive lysophospholipids that activate G protein-coupled receptors that stimulate phosphatidylinositol 3-kinase (PI3K), Ras, and Rho effector pathways involved in vascular cell survival, proliferation, adhesion, and migration. Previous studies have shown that anastellin, a fragment of the first type III module of fibronectin, functions as an antiangiogenic peptide suppressing tumor growth and metastasis. We have previously shown that anastellin blocks serum-dependent proliferation of microvessel endothelial cells (MVEC) by affecting extracellular signal-regulated kinase (ERK)-dependent G(1)-S transition. However, the mechanism by which anastellin regulates endothelial cell function remains unclear. In the present study, we mapped several lysophospholipid-mediated signaling pathways in MVEC and examined the effects of anastellin on LPA- and S1P-induced MVEC proliferation, migration, and cytoskeletal organization. Both LPA and S1P activated PI3K, Ras/ERK, and Rho/Rho kinase pathways, leading to migration, G(1)-S cell cycle progression, and stress fiber formation, respectively. Stimulation of proliferation by LPA/S1P occurred through a G(i)-dependent Ras/ERK pathway, which was independent of growth factor receptors and PI3K and Rho/Rho kinase signaling. Although LPA and S1P activated both PI3K/Akt and Ras/ERK signaling through G(i), anastellin inhibited only the Ras/ERK pathway. Stress fiber formation in response to LPA was dependent on Rho/Rho kinase but independent of G(i) and unaffected by anastellin. These results suggest that lysophospholipid mediators of G(i) activation leading to PI3K/Akt and Ras/ERK signaling bifurcate downstream of G(i) and that anastellin selectively inhibits the Ras/ERK arm of the pathway.
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Affiliation(s)
- Anthony Ambesi
- Center for Cell Biology and Cancer Research (MC-165), Albany Medical College, Albany, NY 12208, USA
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183
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Abstract
Several cytokine families have roles in the development, maintenance, and remodeling of the microcirculation. Of these, the vascular endothelial growth factor (VEGF) family is one of the best studied and one of the most complex. Five VEGF ligand genes and five cell-surface receptor genes are known in the human, and each of these may be transcribed as multiple splice isoforms to generate an extensive family of proteins, many of which are subject to further proteolytic processing. Using the VEGF family as an example, we describe the current knowledge of growth-factor expression, processing, and transport in vivo. Experimental studies and computational simulations are being used to measure and predict the activity of these molecules, and we describe avenues of research that seek to fill the remaining gaps in our understanding of VEGF family behavior.
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Affiliation(s)
- Feilim Mac Gabhann
- Department of Biomedical Engineering, University of Virginia, Charlottesville, Virginia 22908, USA.
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184
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Wu FTH, Stefanini MO, Gabhann FM, Popel AS. Modeling of growth factor-receptor systems from molecular-level protein interaction networks to whole-body compartment models. Methods Enzymol 2009; 467:461-497. [PMID: 19897104 DOI: 10.1016/s0076-6879(09)67018-x] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Most physiological processes are subjected to molecular regulation by growth factors, which are secreted proteins that activate chemical signal transduction pathways through binding of specific cell-surface receptors. One particular growth factor system involved in the in vivo regulation of blood vessel growth is called the vascular endothelial growth factor (VEGF) system. Computational and numerical techniques are well suited to handle the molecular complexity (the number of binding partners involved, including ligands, receptors, and inert binding sites) and multiscale nature (intratissue vs. intertissue transport and local vs. systemic effects within an organism) involved in modeling growth factor system interactions and effects. This chapter introduces a variety of in silico models that seek to recapitulate different aspects of VEGF system biology at various spatial and temporal scales: molecular-level kinetic models focus on VEGF ligand-receptor interactions at and near the endothelial cell surface; mesoscale single-tissue 3D models can simulate the effects of multicellular tissue architecture on the spatial variation in VEGF ligand production and receptor activation; compartmental modeling allows efficient prediction of average interstitial VEGF concentrations and cell-surface VEGF signaling intensities across multiple large tissue volumes, permitting the investigation of whole-body intertissue transport (e.g., vascular permeability and lymphatic drainage). The given examples will demonstrate the utility of computational models in aiding both basic science and clinical research on VEGF systems biology.
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Affiliation(s)
- Florence T H Wu
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Marianne O Stefanini
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Feilim Mac Gabhann
- Department of Biomedical Engineering, Institute for Computational Medicine, Johns Hopkins University, Baltimore, Maryland, USA
| | - Aleksander S Popel
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
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185
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Cheung JWC, Walker GC. Immuno-atomic force microscopy characterization of adsorbed fibronectin. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2008; 24:13842-9. [PMID: 19360949 DOI: 10.1021/la802452v] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
The fibronectin (Fn) binding conformation on mica and ultraflat poly(D,L-lactide-co-glycolide) (UPLGA) was characterized using atomic force microscopy (AFM). AFM topographic images showed that Fn was in an extended form on mica and in a compact structure on UPLGA. With immuno-AFM, an antibody (Ab(hep)) was used to characterize the Fn binding conformation. When Fn opens its binding site for an antibody upon adsorption to a surface, the resulting Fn-antibody complex creates an additional peak in the sample's height distribution. Immuno-AFM uses this change to detect antigen-antibody binding. In this letter, height histograms (distributions) were generated using the mean true height of molecules, which was measured by examining the histogram for each individual molecule and subtracting the mica background. Mean true height values were obtained from the histograms and showed that Fn and Ab(hep) formed complexes on mica, signifying that one of the heparin binding sites on Fn was open when Fn was adsorbed to mica. The mean true height of the Fn-antibody complex from the histogram is greater than expected, suggesting that the antibody had pulled the extended "arms" of Fn together and caused an Fn conformation change upon binding. The height histograms can illustrate the Fn binding conformation and other antigen-antibody binding.
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Affiliation(s)
- Jane W C Cheung
- Department of Chemistry, University of Toronto, Toronto, Ontario, Canada M5S 3H6.
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186
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Faralli JA, Schwinn MK, Gonzalez JM, Filla MS, Peters DM. Functional properties of fibronectin in the trabecular meshwork. Exp Eye Res 2008; 88:689-93. [PMID: 18835267 DOI: 10.1016/j.exer.2008.08.019] [Citation(s) in RCA: 56] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 08/21/2008] [Accepted: 08/25/2008] [Indexed: 11/17/2022]
Abstract
Fibronectin plays a number of important roles in the extracellular matrix (ECM) including providing structural support and signaling cues for cell survival, migration, differentiation, gene expression, growth factor signaling, and cell contractility. In this review, we examine recent findings about the biological and structural properties of fibronectin and discuss how these properties could contribute to the regulation of aqueous humor (AH) outflow in the trabecular meshwork (TM).
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Affiliation(s)
- Jennifer A Faralli
- Department of Pathology & Laboratory Medicine, School of Medicine and Public Health, University of Wisconsin, Madison, WI 53706, USA
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187
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Xu H, Hu F, Sado Y, Ninomiya Y, Borza DB, Ungvari Z, Lagamma EF, Csiszar A, Nedergaard M, Ballabh P. Maturational changes in laminin, fibronectin, collagen IV, and perlecan in germinal matrix, cortex, and white matter and effect of betamethasone. J Neurosci Res 2008; 86:1482-500. [PMID: 18214989 DOI: 10.1002/jnr.21618] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Germinal matrix is selectively vulnerable to hemorrhage in premature infants, and use of prenatal betamethasone is associated with a lower occurrence of germinal matrix hemorrhage. Because the major components of extracellular matrix of the cerebral vasculature-laminin, fibronectin, collagen IV, and perlecan-provide structural stability to blood vessels, we examined whether the expression of these molecules was decreased in the germinal matrix and affected by betamethasone. In both human fetuses and premature infants, fibronectin was significantly lower in the germinal matrix than in the cortical mantle or white matter anlagen. Conversely, laminin alpha1 gene expression was greater in the human germinal matrix compared with the cortical mantle or white matter. Expression of alpha1- and alpha2(IV) collagen chains increased with advancing gestational age. Low-dose prenatal betamethasone treatment enhanced fibronectin level by 1.5-2-fold whereas a high dose reduced fibronectin expression by 2-fold in rabbit pups. Because fibronectin provides structural stability to the blood vessels, its reduced expression in the germinal matrix may contribute to the fragility of germinal matrix vasculature and the propensity to hemorrhage in premature neonates.
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Affiliation(s)
- Hongmin Xu
- Department of Pediatrics, New York Medical College-Westchester Medical Center, Valhalla, New York 10595, USA
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188
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Construction of multi-functional extracellular matrix proteins that promote tube formation of endothelial cells. Biomaterials 2008; 29:2977-86. [DOI: 10.1016/j.biomaterials.2008.04.006] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Accepted: 04/02/2008] [Indexed: 10/22/2022]
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189
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Rahman S, Patel YM, Wijelath ES, Sobel MS. Therapeutic potential of novel modulators of neovascularization. Future Cardiol 2008; 4:409-26. [PMID: 19804321 DOI: 10.2217/14796678.4.4.409] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Neovacularization is an important biological process whereby new blood vessels develop in both health and disease. During development, blood vessels are formed from mesodermal cells in a process called vasculogenesis. The vascular network then expands by the sprouting of new vessel networks from pre-established vessels in a process known as angiogenesis. However, in adult life, undesirable neovascularization is associated with tumor development and a growing list of 'angiogenesis-dependent' diseases, including cardiovascular complications. Furthermore, diseases characterized by ischemia-induced tissue damage cause a neovascularization response to facilitate tissue repair. Recent research has identified novel molecular and cellular mediators of neovascularization that, in adult life, recapitulate angiogenic processes observed during embryonic development. The discovery of vascular progenitor cells and new molecules that display selective functions in modulating endothelial cell fate, migration and patterning, vessel morphogenesis and the amplification of angiogenic signaling by regulating the master signal VEGF, opens the door to new clinical strategies that target angiogenesis-dependent diseases or that can promote therapeutic neovascularization.
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Affiliation(s)
- Salman Rahman
- King's College London School of Medicine, Department of Cardiology, Cardiovascular Division, UK.
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190
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A proangiogenic peptide derived from vascular endothelial growth factor receptor-1 acts through α5β1 integrin. Blood 2008; 111:3479-88. [DOI: 10.1182/blood-2007-03-077537] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
AbstractVascular endothelial growth factor receptor-1 (VEGFR-1) is a tyrosine kinase receptor for growth factors of the VEGF family. Endothelial cells express a membrane-bound and a soluble variant of this protein, the latter being mainly considered as a negative regulator of VEGF-A signaling. We previously reported that the soluble form is deposited in the extracellular matrix produced by endothelial cells in culture and is able to promote cell adhesion and migration through binding to α5β1 integrin. In this study, we demonstrate that the Ig-like domain II of VEGFR-1, which contains the binding determinants for the growth factors, is involved in the interaction with α5β1 integrin. To identify domain regions involved in integrin binding, we designed 12 peptides putatively mimicking the domain II surface and tested their ability to inhibit α5β1-mediated endothelial cell adhesion to soluble VEGFR-1 and directly support cell adhesion. One peptide endowed with both these properties was identified and shown to inhibit endothelial cell migration toward soluble VEGFR-1 as well. This peptide directly binds α5β1 integrin, but not VEGF-A, inducing endothelial cell tubule formation in vitro and neoangiogenesis in vivo. Alanine scanning mutagenesis of the peptide defined which residues were responsible for its biologic activity and integrin binding.
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191
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Ball SG, Shuttleworth CA, Kielty CM. Mesenchymal stem cells and neovascularization: role of platelet-derived growth factor receptors. J Cell Mol Med 2008; 11:1012-30. [PMID: 17979880 PMCID: PMC4401270 DOI: 10.1111/j.1582-4934.2007.00120.x] [Citation(s) in RCA: 130] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
There is now accumulating evidence that bone marrow-derived mesenchymal stem cells (MSCs) make an important contribution to postnatal vasculogenesis, especially during tissue ischaemia and tumour vascularization. Identifying mechanisms which regulate the role of MSCs in vasculogenesis is a key therapeutic objective, since while increased neovascularization can be advantageous during tissue ischaemia, it is deleterious during tumourigenesis. The potent angiogenic stimulant vascular endothelial growth factor (VEGF) is known to regulate MSC mobilization and recruitment to sites of neovascularization, as well as directing the differentiation of MSCs to a vascular cell fate. Despite the fact that MSCs did not express VEGF receptors, we have recently identified that VEGF-A can stimulate platelet-derived growth factor (PDGF) receptors, which regulates MSC migration and proliferation. This review focuses on the role of PDGF receptors in regulating the vascular cell fate of MSCs, with emphasis on the function of the novel VEGF-A/PDGF receptor signalling mechanism.
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Affiliation(s)
- Stephen G Ball
- UK Centre for Tissue Engineering, Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, UK
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192
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193
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Viji RI, Kumar VBS, Kiran MS, Sudhakaran PR. Angiogenic response of endothelial cells to heparin-binding domain of fibronectin. Int J Biochem Cell Biol 2007; 40:215-26. [PMID: 17766169 DOI: 10.1016/j.biocel.2007.07.009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2007] [Revised: 06/29/2007] [Accepted: 07/17/2007] [Indexed: 10/23/2022]
Abstract
Interaction of endothelial cells with cell-binding domain of fibronectin through integrin receptors is important in the process of angiogenesis. The present study was designed to examine the role of heparin-binding domain of fibronectin in angiogenesis using human umbilical vein endothelial cells. Attachment of endothelial cells in vitro to heparin-binding domain of fibronectin was inhibited by heparin. Chick chorioallantoic membrane assay revealed the proangiogenic nature of heparin-binding domain. Analysis by reverse transcription-polymerase chain reaction showed an increase in the expression of vascular endothelial growth factor and its receptor mRNA. Enzyme-linked immunosorbent assay showed a significant increase in the level of vascular endothelial growth factor secreted by cells maintained on heparin-binding domain. Treatment with calphostin C, an inhibitor of protein kinase C, decreased the expression of vascular endothelial growth factor receptor 2. Chick chorioallantoic membrane assay showed that the vascular endothelial growth factor secreted by cells maintained on heparin-binding domain was biologically more active, which appeared to be due to a decrease in its poly-adenosine diphosphate ribosylation. Binding assays showed that heparin-binding domain preferably binds unmodified vascular endothelial growth factor as compared to intact fibronectin. It is concluded that the heparin-binding domain of fibronectin by itself can promote angiogenesis in endothelial cells possibly by interaction with cell surface heparan sulphate proteoglycans involving protein kinase C dependent signaling and making available more active form of vascular endothelial growth factor to the cells.
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Affiliation(s)
- R I Viji
- Department of Biochemistry, University of Kerala, Thiruvananthapuram, Kerala 695 581, India.
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194
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Abstract
The extracellular matrix plays a number of important roles, among them providing structural support and information to cellular structures such as blood vessels imbedded within it. As more complex organisms have evolved, the matrix ability to direct signalling towards the vasculature and remodel in response to signalling from the vasculature has assumed progressively greater importance. This review will focus on the molecules of the extracellular matrix, specifically relating to vessel formation and their ability to signal to the surrounding cells to initiate or terminate processes involved in blood vessel formation.
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Affiliation(s)
- John M Rhodes
- *Correspondence to: Michael SIMONS Section of Cardiology, Dartmouth-Hitchcock Medical Center, One Medical Center Drive, Lebanon, NH 03756, USA.; Tel.: 603 650 3540; E-mail:
| | - Michael Simons
- *Correspondence to: Michael SIMONS Section of Cardiology, Dartmouth-Hitchcock Medical Center, One Medical Center Drive, Lebanon, NH 03756, USA.; Tel.: 603 650 3540; E-mail:
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195
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Galownia NC, Kushiro K, Gong Y, Asthagiri AR. Selective desensitization of growth factor signaling by cell adhesion to fibronectin. J Biol Chem 2007; 282:21758-66. [PMID: 17540764 DOI: 10.1074/jbc.m703577200] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Cell adhesion to the extracellular matrix is required to execute growth factor (GF)-mediated cell behaviors, such as proliferation. A major underlying mechanism is that cell adhesion enhances GF-mediated intracellular signals, such as extracellular signal-regulated kinase (Erk). However, because GFs use distinct mechanisms to activate Ras-Erk signaling, it is unclear whether adhesion-mediated enhancement of Erk signaling is universal to all GFs. We examined this issue by quantifying the dynamics of Erk signaling induced by epidermal growth factor, basic fibroblast growth factor (bFGF), and platelet-derived growth factor (PDGF) in NIH-3T3 fibroblasts. Adhesion to fibronectin-coated surfaces enhances Erk signaling elicited by epidermal growth factor but not by bFGF or PDGF. Unexpectedly, adhesion is not always a positive influence on GF-mediated signaling. At critical subsaturating doses of PDGF or bFGF, cell adhesion ablates Erk signaling; that is, adhesion desensitizes the cell to GF stimulation, rendering the signaling pathway unresponsive to GF. Interestingly, the timing of growth factor stimulation proved critical to the desensitization process. Erk activation significantly improved only when pre-exposure to adhesion was completely eliminated; thus, concurrent stimulation by GF and adhesion was able to partially rescue adhesion-mediated desensitization of PDGF- and bFGF-mediated Erk and Akt signaling. These findings suggest that adhesion-mediated desensitization occurs with rapid kinetics and targets a regulatory point upstream of Ras and proximal to GF receptor activation. Thus, adhesion-dependent Erk signaling is not universal to all GFs but, rather, is GF-specific with quantitative features that depend strongly on the dose and timing of GF exposure.
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Affiliation(s)
- Niki C Galownia
- Division of Chemistry and Chemical Engineering, California Institute of Technology, Pasadena, CA 91125, USA
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196
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Ball SG, Shuttleworth CA, Kielty CM. Vascular endothelial growth factor can signal through platelet-derived growth factor receptors. ACTA ACUST UNITED AC 2007; 177:489-500. [PMID: 17470632 PMCID: PMC2064818 DOI: 10.1083/jcb.200608093] [Citation(s) in RCA: 213] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Vascular endothelial growth factor (VEGF-A) is a crucial stimulator of vascular cell migration and proliferation. Using bone marrow-derived human adult mesenchymal stem cells (MSCs) that did not express VEGF receptors, we provide evidence that VEGF-A can stimulate platelet-derived growth factor receptors (PDGFRs), thereby regulating MSC migration and proliferation. VEGF-A binds to both PDGFRalpha and PDGFRbeta and induces tyrosine phosphorylation that, when inhibited, results in attenuation of VEGF-A-induced MSC migration and proliferation. This mechanism was also shown to mediate human dermal fibroblast (HDF) migration. VEGF-A/PDGFR signaling has the potential to regulate vascular cell recruitment and proliferation during tissue regeneration and disease.
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Affiliation(s)
- Stephen G Ball
- UK Centre for Tissue Engineering and 2Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, The University of Manchester, Manchester, England, UK
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