RESUMO
Wet age-related macular degeneration (AMD) and diabetic retinopathy are the leading causes of blindness through increased angiogenesis. Although VEGF-neutralizing proteins provide benefit, inconsistent responses indicate a need for new therapies. We previously identified the Fibulin-7 C-terminal fragment (Fbln7-C) as an angiogenesis inhibitor in vitro. Here we show that Fbln7-C inhibits neovascularization in vivo, in both a model of wet AMD involving choroidal neovascularization (CNV) and diabetic retinopathy involving oxygen-induced ischemic retinopathy. Furthermore, a short peptide sequence from Fbln7-C is responsible for the anti-angiogenic properties of Fbln7-C. Our work suggests Fbln7-C as a therapeutic candidate for wet AMD and ischemic retinopathy.
Assuntos
Inibidores da Angiogênese/farmacologia , Proteínas de Ligação ao Cálcio/farmacologia , Corioide/irrigação sanguínea , Neovascularização de Coroide/prevenção & controle , Fragmentos de Peptídeos/farmacologia , Neovascularização Retiniana/prevenção & controle , Vasos Retinianos/efeitos dos fármacos , Degeneração Macular Exsudativa/prevenção & controle , Animais , Proteínas de Ligação ao Cálcio/síntese química , Proteínas de Ligação ao Cálcio/genética , Neovascularização de Coroide/genética , Neovascularização de Coroide/metabolismo , Neovascularização de Coroide/patologia , Modelos Animais de Doenças , Feminino , Camundongos Endogâmicos C57BL , Fragmentos de Peptídeos/síntese química , Neovascularização Retiniana/genética , Neovascularização Retiniana/metabolismo , Neovascularização Retiniana/patologia , Vasos Retinianos/metabolismo , Vasos Retinianos/patologia , Degeneração Macular Exsudativa/genética , Degeneração Macular Exsudativa/metabolismo , Degeneração Macular Exsudativa/patologiaRESUMO
Human laminin-511 (α5ß1γ1) and its truncated protein, laminin-511 E8 fragment, bind to integrin α6ß1 and have been widely used for embryonic stem cell and induced pluripotent stem cell culture under feeder-free conditions. In this study, we focused on human laminin α5 chain G domain, which is thought to be critical for the biological functions of laminin-511, and screened its biologically active sequences using a synthetic peptide library. We synthesized 115 peptides (hA5G1-hA5G115) covering the entire laminin α5 chain G domain and evaluated cell attachment activity using both the peptide-coated plate and peptide-chitosan matrix (peptide-ChtM) assays. Seventeen peptides demonstrated cell attachment activity in the assays. Both hA5G18 and hA5G26-coated plates and hA5G74-ChtMs promoted integrin ß1-mediated cell attachment. These findings are useful for the study of molecular mechanisms of laminin-511, and the active peptides have a potential for use as a molecular probe for cell adhesion receptors.
Assuntos
Fibroblastos/efeitos dos fármacos , Laminina/química , Laminina/metabolismo , Fragmentos de Peptídeos/farmacologia , Relação Dose-Resposta a Droga , Humanos , Fragmentos de Peptídeos/análise , Fragmentos de Peptídeos/síntese química , Domínios Proteicos , Relação Estrutura-AtividadeRESUMO
Human induced pluripotent stem cells (hiPSCs) grow indefinitely in culture and have the potential to regenerate various tissues. In the development of cell culture systems, a fragment of laminin-511 (LM511-E8) was found to improve the proliferation of stem cells. The adhesion of undifferentiated cells to LM511-E8 is mainly mediated through integrin α6ß1. However, the involvement of non-integrin receptors remains unknown in stem cell culture using LM511-E8. Here, we show that dystroglycan (DG) is strongly expressed in hiPSCs. The fully glycosylated DG is functionally active for laminin binding, and although it has been suggested that LM511-E8 lacks DG binding sites, the fragment does weakly bind to DG. We further identified the DG binding sequence in LM511-E8, using synthetic peptides, of which, hE8A5-20 (human laminin α5 2688-2699: KTLPQLLAKLSI) derived from the laminin coiled-coil domain, exhibited DG binding affinity and cell adhesion activity. Deletion and mutation studies show that LLAKLSI is the active core sequence of hE8A5-20, and that, K2696 is a critical amino acid for DG binding. We further demonstrated that hiPSCs adhere to hE8A5-20-conjugated chitosan matrices. The amino acid sequence of DG binding peptides would be useful to design substrata for culture system of undifferentiated and differentiated stem cells.
Assuntos
Adesão Celular , Distroglicanas/metabolismo , Células-Tronco Pluripotentes Induzidas/metabolismo , Laminina/metabolismo , Fragmentos de Peptídeos/metabolismo , Sequência de Aminoácidos , Biomarcadores , Células Cultivadas , Matriz Extracelular , Imunofluorescência , Humanos , Laminina/química , Fragmentos de Peptídeos/química , Ligação Proteica , Transporte ProteicoRESUMO
Extracellular matrix molecules are recognized by several integrin subtypes, making identification of cross-talk among different integrin subtypes difficult. Here, we evaluated the cross-talk of integrin subtypes using four different integrin-binding peptides (FIB1; integrin αvß3/α5ß1, A2G10; integrin α6ß1, EF1zz; integrin α2ß1, or 531; integrin α3ß1) derived from extracellular matrix molecules. Various combinations of two different integrin-binding peptides were mixed and conjugated on a chitosan matrix at various molar ratios and were evaluated for cell attachment activity. FIB1/A2G10 (molar ratio 5:5; total 10 nmol/well)-chitosan matrix significantly enhanced cell attachment activity compared with sum of the cell attachment activity on FIB1 (5 nmol/well)-chitosan matrices and A2G10 (5 nmol/well)-chitosan matrices, respectively. However, none of the other peptides showed a significant activity change when they were mixed and conjugated on a chitosan matrix. We investigated the mechanisms of this enhancement. FIB1/A2G10 (8:2 or 6:4)-chitosan matrix increased the cell spreading, phosphorylation of focal adhesion kinase at Y397, and slightly decreased phosphorylation of caveolin-1 at Y14 in fibroblasts compared with FIB1-chitosan and A2G10-chitosan matrices. These results indicate that FIB1/A2G10 (8:2 or 6:4)-chitosan matrix synergistically enhances cell attachment, suggesting that integrins αvß3/α5ß1 and α6ß1 are involved in a cross-talk and synergistically enhance cell attachment. These findings also suggest that the mixed peptide-chitosan matrix system can regulate the ratio of two different peptides and is useful for evaluating cellular functions through receptor-specific cross-talk. Further, FIB1/A2G10 (8:2 or 6:4)-chitosan matrix could be a useful material for tissue engineering.
Assuntos
Quitosana/química , Fibroblastos/citologia , Integrinas/metabolismo , Peptídeos/química , Alicerces Teciduais/química , Animais , Materiais Biocompatíveis/química , Materiais Biocompatíveis/metabolismo , Adesão Celular , Linhagem Celular , Quitosana/metabolismo , Fibroblastos/metabolismo , Humanos , Camundongos , Peptídeos/metabolismo , Ligação ProteicaRESUMO
Biomaterials are important for cell and tissue engineering. Chitosan is widely used as a scaffold because it is easily modified using its amino groups, can easily form a matrix, is stable under physiological conditions, and is inactive for cell adhesion. Chitosan is an excellent platform for peptide ligands, especially cell adhesive peptides derived from extracellular matrix (ECM) proteins. ECM proteins, such as collagen, fibronectin, and laminin, are multifunctional and have diverse cell attachment sites. Various cell adhesive peptides have been identified from the ECM proteins, and these are useful to design functional biomaterials. The cell attachment activity of peptides is influenced by the solubility, conformation, and coating efficiency to solid materials, whereas immobilization of peptides to a polysaccharide such as chitosan avoids these problems. Peptideâ»chitosan matrices promote various biological activities depending on the peptide. When the peptides are immobilized to chitosan, the activity of the peptides is significantly enhanced. Further, mixed peptideâ»chitosan matrices, conjugated with more than one peptide on a chitosan matrix, interact with multiple cellular receptors and promote specific biological responses via receptor cross-talk. Receptor cross-talk is important for mimicking the biological activity of ECM and the proteins. The mixed peptideâ»chitosan matrix approach is useful to develop biomaterials as a synthetic ECM for cell and tissue engineering.
Assuntos
Quitosana/análogos & derivados , Peptídeos/química , Engenharia Tecidual/métodos , Alicerces Teciduais/química , Sequência de Aminoácidos , Animais , Materiais Biocompatíveis/química , Adesão Celular , Proteínas da Matriz Extracelular/química , Humanos , Integrinas/químicaRESUMO
Many cell-adhesive peptides have been identified from extracellular matrix (ECM) proteins, such as collagen, fibronectin, laminin, and vitronectin. ECM proteins have various cell-adhesive sequences. Most peptides demonstrate cell-adhesive activity when simply coated on a tissue culture plate, but solubility, conformation, and coating efficiency of the peptides can significantly alter their biological function. Evaluation of peptide cell-adhesive activity using peptide-conjugated polysaccharide constructs is a useful strategy for overcoming peptide solubility and conformation problems. After a simple modification of the polysaccharides, various polysaccharides (chitosan, alginate, and hyaluronate) can fix the peptides on the tissue culture plate quantitatively. The peptide-polysaccharide strategy can be used to fix different active peptides to the polysaccharide at same time, thus, mimicking the biological functions of the ECM. This paper describes the modification of polysaccharides that are suitable for covalently coupling the peptides and evaluation of the cell-adhesive activity of peptide as a peptide-polysaccharide matrix. © 2018 by John Wiley & Sons, Inc.
Assuntos
Técnicas Citológicas/métodos , Peptídeos/farmacologia , Polissacarídeos/farmacologia , Alginatos/síntese química , Animais , Proteínas Morfogenéticas Ósseas/farmacologia , Adesão Celular/efeitos dos fármacos , Derme/citologia , Fibroblastos/citologia , Humanos , Ácido Hialurônico/síntese química , Crescimento Neuronal/efeitos dos fármacos , Células PC12 , RatosRESUMO
Antibody-drug conjugates (ADCs) are attractive in cancer therapy because they can directly bind to cancer cells and provide anticancer activity. To kill cancer cells with ADCs, the target antigens are required not only to be highly and/or selectively expressed on cancer cells but also internalized by the cells. CD239, also known as the Lutheran blood group glycoprotein (Lu) or basal cell adhesion molecule (B-CAM), is a specific receptor for laminin α5, a major component of basement membranes. Here, we show that CD239 is strongly expressed in a subset of breast cancer cells and internalized into the cells. We also produced a human single-chain variable fragment (scFv) specific to CD239 fused with human IgG1 Fc, called C7-Fc. The binding affinity of the C7-Fc antibody is similar to that of mouse monoclonal antibodies. Although the C7-Fc antibody alone does not influence cellular functions, when conjugated with a fragment of diphtheria toxin lacking the receptor-binding domain (fDT), it can selectively kill breast cancer cells. Interestingly, fDT-bound C7-Fc shows anticancer activity in CD239-highly positive SKBR3 cells, but not in weakly positive cells. Our results show that CD239 is a promising antigen for ADC-based breast cancer therapy.
Assuntos
Neoplasias da Mama/metabolismo , Moléculas de Adesão Celular/metabolismo , Endocitose , Sistema do Grupo Sanguíneo Lutheran/metabolismo , Animais , Biomarcadores Tumorais , Neoplasias da Mama/tratamento farmacológico , Neoplasias da Mama/genética , Neoplasias da Mama/patologia , Moléculas de Adesão Celular/antagonistas & inibidores , Moléculas de Adesão Celular/genética , Linhagem Celular Tumoral , Testes Imunológicos de Citotoxicidade , Feminino , Humanos , Imunoconjugados/farmacologia , Fragmentos Fc das Imunoglobulinas/imunologia , Imuno-Histoquímica , Sistema do Grupo Sanguíneo Lutheran/genética , Camundongos , Ligação Proteica , Transporte Proteico , Anticorpos de Cadeia Única/farmacologiaRESUMO
The first rapid and efficient chemical synthesis of a cyclic Arg-Gly-Asp (RGD) peptide containing a chloroalkene dipeptide isostere (CADI) is reported. By a developed synthetic method, an N-tert-butylsulfonyl protected CADI was obtained utilizing diastereoselective allylic alkylation as a key reaction. This CADI was also transformed into an N-Fmoc protected CADI in a few steps. The CADI was used in Fmoc-based solid-phase peptide synthesis. The first synthesis of a CADI-containing cyclic RGD peptide was successful, and the synthesized CADI-containing peptidomimetic was found to be a more potent inhibitor against integrin-mediated cell attachment than the parent cyclic peptide.
RESUMO
Laminin-511, a major component of endothelial basement membrane, consists of α5, ß1, and γ1 chains. The short arm region of the α5 chain is a structural feature of endothelial laminins. In this study, we identified active sequences for human umbilical vein endothelial cells (HUVECs) using recombinant proteins and synthetic peptides. The short arm of the α5 chain contains three globular domains [laminin N-terminal globular domain, laminin 4 domain a, and laminin 4 domain b (LN, L4a, and L4b)] and three rod-like elements [laminin epidermal growth factor-like domain a, b, and c (LEa, LEb, and LEc)]. The cell attachment assay using recombinant proteins showed that RGD-independent cell attachment sites were localized in the α5LN-LEa domain. Further, we synthesized 70 peptides covering the amino acid sequences of the α5LN-LEa domain. Of the 70 peptides, A5-16 (mouse laminin α5 230-243: LENGEIVVSLVNGR) potently exhibited endothelial cell attachment activity. An active sequence analysis using N-terminally and C-terminally truncated A5-16 peptides showed that the nine-amino acid sequence IVVSLVNGR was critical for the endothelial cell attachment activity. Cell adhesion to the peptides was dependent on both cations and heparan sulfate. Further, the A5-16 peptide inhibited the capillary-like tube formation of HUVECs with the cells forming small clumps with short tubes. The eight-amino acid sequence EIVVSLVN in the A5-16 peptide was critical to inhibit HUVEC tube formation. This amino acid sequence could be useful for grafts and thus modulate endothelial cell behavior for vascular surgery. Copyright © 2017 European Peptide Society and John Wiley & Sons, Ltd.
Assuntos
Laminina/química , Peptídeos/química , Sequência de Aminoácidos , Animais , Adesão Celular/fisiologia , Células Endoteliais , Células HEK293 , Células Endoteliais da Veia Umbilical Humana , Humanos , Camundongos , Proteínas Recombinantes/químicaRESUMO
The Lutheran glycoprotein (Lu), also known as basal cell adhesion molecule (B-CAM), is an Ig superfamily (IgSF) transmembrane receptor for laminin α5. Although Lu is not present in normal hepatocytes, its expression is significantly increased in hepatocellular carcinoma (HCC). In this study, we isolated thirteen phage antibodies to Lu from a phage library of peripheral blood from HCC patients, suggesting that these patients produced autoantibodies against endogenous Lu. To characterize the phage antibodies, we determined the Lu domains they recognize. The extracellular domain of Lu contains five IgSF domains, D1-D2-D3-D4-D5. The epitope of one phage antibody (A7) was localized to the D5 domain. The other phage antibodies recognized the D2 domain, which is also recognized by a function blocking mouse monoclonal antibody. One of the antibodies to D2 (C7) inhibited the binding of Lu to ligand, and it also prevented tumor cell migration on laminin-511 (LM-511). However, the C7 scFv purified from the periplasm fraction of bacteria did not exhibit the inhibitory effects, indicating that the scFv form could not sterically inhibit the binding of Lu to LM-511. We also identified the amino acid residues that form the epitope recognized by the C7 phage antibody. Mutagenesis studies showed that Arg247 is necessary for forming the epitope. The C7 phage antibody and its epitope may be useful for developing drugs to prevent HCC progression and/or metastasis.
Assuntos
Anticorpos Monoclonais/imunologia , Anticorpos Monoclonais/farmacologia , Técnicas de Visualização da Superfície Celular , Glicoproteínas/imunologia , Sistema do Grupo Sanguíneo Lutheran/imunologia , Sequência de Aminoácidos , Anticorpos Monoclonais/química , Anticorpos Monoclonais/isolamento & purificação , Linhagem Celular Tumoral , Movimento Celular/efeitos dos fármacos , Ensaio de Imunoadsorção Enzimática , Mapeamento de Epitopos/métodos , Epitopos/química , Epitopos/imunologia , Humanos , Biblioteca de Peptídeos , Ligação Proteica/imunologia , Domínios e Motivos de Interação entre Proteínas/imunologia , Anticorpos de Cadeia Única/química , Anticorpos de Cadeia Única/isolamento & purificação , Anticorpos de Cadeia Única/farmacologiaRESUMO
Peptide-conjugated polysaccharide matrices using bioactive laminin-derived peptides are useful biomaterials for tissue and cell engineering. Here, we demonstrate an easy handling preparation method for peptide-polysaccharide matrices using polyion complex with both alginate and chitosan. First, aldehyde-alginate was synthesized by oxidization of alginate using NaIO4 , and then, reacted with Cys-peptides. Next, the peptide-alginate solution was added to a chitosan-coated plate, and the peptide-polyion complex matrices (peptide-PCMs) were prepared. The peptide-PCMs using an integrin αvß3-binding peptide (A99a: ALRGDN, mouse laminin α1 chain 1145-1150) and an integrin α2ß1-binding peptide (EF1XmR: RLQLQEGRLHFXFD, X = Nle, mouse laminin α1 chain 2751-2763) showed strong cell attachment activity in a dose-dependent manner. When we examined the effect of various spacers on the biological activity of A99a-PCM, hydrophobic and long spacers enhanced the cell attachment activity. Further, the A99a-PCM with the spacers strongly promoted neurite outgrowth. The polyion complex method is an easy way to obtain insolubilized matrix and is widely applicable for various polysaccharides. The peptide-PCM is useful as a biomaterial for cell and tissue engineering.
Assuntos
Alginatos/química , Quitosana/química , Peptídeos/química , Aldeídos/química , Sequência de Aminoácidos , Animais , Anticorpos/química , Anticorpos/imunologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular , Ácido Edético/química , Heparina/química , Humanos , Integrina alfa1beta1/química , Integrina alfa1beta1/imunologia , Integrina alfaVbeta3/química , Integrina alfaVbeta3/imunologia , Laminina/química , Camundongos , Microscopia de Fluorescência , Neuritos/metabolismo , Oxirredução , Peptídeos/síntese química , Peptídeos/metabolismo , Peptídeos/farmacologiaRESUMO
Mimicking the biological function of the extracellular matrix is an approach to developing cell adhesive biomaterials. The RGD peptide, derived from fibronectin (Fn), mainly binds to integrin αvß3 and has been widely used as a cell adhesive peptide on various biomaterials. However, cell adhesion to Fn is thought to be mediated by several integrin subtypes and syndecans. In this study, we synthesized an RGD-containing peptide (FIB1) and four integrin α4ß1-binding-related motif-containing peptides (LDV, IDAPS, KLDAPT, and PRARI) and constructed peptide-chitosan matrices. The FIB1-chitosan matrix promoted human dermal fibroblast (HDF) attachment, and the C-terminal elongated PRARI (ePRARI-C)-conjugated chitosan matrix significantly promoted HDF attachment through integrin α4ß1 and syndecan binding. Next, we constructed a mixed ePRARI-C- and FIB1-chitosan matrix to develop a Fn mimetic biomaterial. The mixed ePRARI-C/FIB1-chitosan matrix promoted significantly better cell attachment and neurite outgrowth compared to those of either ePRARI-C- or FIB1-chitosan matrices. HDF adhesion to the ePRARI-C/FIB1-chitosan matrix was mediated by integrin, α4ß1, α5ß1, and αvß3, similar to HDF adhesion to Fn. These data suggest that an ePRARI-C/FIB1-chitosan matrix can be used as a tool to analyze the multiple functions of Fn and can serve as a Fn-mimetic biomaterial.
RESUMO
Epithelial cells, both normal and precancerous, stably anchor to basement membranes, whereas malignant tumors pass through them to achieve metastasis. Of basement membrane components, laminin-511 (α5, ß1, γ1; LM-511) has been found to be a major isoform in many adult basement membranes. Several studies have shown that LM-511 promotes not only cell adhesion but also tumor cell migration. Thus, LM-511 can be viewed like two distinct molecules in normal vs. tumor cells; tumor cells seem to be able to alter their response (adhesive vs. migratory) to LM-511. In this study we examined the effects of biologically active molecules on A549 lung adenocarcinoma cell adhesion to LM-511. Of them, phorbol 12-myristate 13-acetate (PMA) induced transition to a rounded cell shape and significantly promoted cell migration on LM-511. The attachment of PMA-treated A549 cells to LM-511 was weaker than that of control cells. PMA-stimulated signaling pathway reduced the binding of integrin α3ß1 to LM-511. Cell migration assays using inhibitors for signal transduction and cytoskeletal organization showed that suppression of cell adhesion via the rho-associated protein kinase (ROCK) pathway promoted tumor cell migration on LM-511. Our results suggest that the ROCK pathway is involved in the transition from static to migratory cell behaviors on LM-511.
Assuntos
Movimento Celular/efeitos dos fármacos , Regulação para Baixo/efeitos dos fármacos , Laminina/farmacologia , Transdução de Sinais/efeitos dos fármacos , Quinases Associadas a rho/metabolismo , Actinas/metabolismo , Anticorpos Monoclonais/farmacologia , Adesão Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Forma Celular/efeitos dos fármacos , Citometria de Fluxo , Células HEK293 , Humanos , Integrina alfa3beta1/metabolismo , Integrina alfa6/metabolismo , Acetato de Tetradecanoilforbol/farmacologia , Vinculina/metabolismoRESUMO
Peptides with cell attachment activity are beneficial component of biomaterials for tissue engineering. Conformational structure is one of the important factors for the biological activities. The EF1 peptide (DYATLQLQEGRLHFMFDLG) derived from laminin promotes cell spreading and cell attachment activity mediated by α2ß1 integrin. Although the sequence of the EF2 peptide (DFATVQLRNGFPYFSYDLG) is homologous sequence to that of EF1, EF2 does not promote cell attachment activity. To determine whether there are structural differences between EF1 and EF2, we performed replica exchange molecular dynamics (REMD) simulations and conventional molecular dynamics (MD) simulations. We found that EF1 and EF2 had ß-sheet structure as a secondary structure around the global minimum. However, EF2 had variety of structures around the global minimum compared with EF1 and has easily escaped from the bottom of free energy. The structural fluctuation of the EF1 is smaller than that of the EF2. The structural variation of EF2 is related to these differences in the structural fluctuation and the number of the hydrogen bonds (H-bonds). From the analysis of H-bonds in the ß-sheet, the number of H-bonds in EF1 is larger than that in EF2 in the time scale of the conventional MD simulation, suggesting that the formation of H-bonds is related to the differences in the structural fluctuation between EF1 and EF2. From the analysis of other non-covalent interactions in the amino acid sequences of EF1 and EF2, EF1 has three pairs of residues with hydrophobic interaction, and EF2 has two pairs. These results indicate that several non-covalent interactions are important for structural stabilization. Consequently, the structure of EF1 is stabilized by H-bonds and pairs of hydrophobic amino acids in the terminals. Hence, we propose that non-covalent interactions around N-terminal and C-terminal of the peptides are crucial for maintaining the ß-sheet structure of the peptides.
Assuntos
Laminina/química , Simulação de Dinâmica Molecular , Peptídeos/química , Conformação Proteica , Sequência de Aminoácidos , Adesão Celular , Ligação de Hidrogênio , Laminina/metabolismo , Dados de Sequência Molecular , Peptídeos/metabolismo , TermodinâmicaRESUMO
Despite the research done on pathological angiogenesis, there is still a need for the development of new therapies against angiogenesis-related diseases. Fibulin-7 (Fbln7) is a member of the extracellular matrix fibulin protein family. The Fbln7 C-terminal fragment, Fbln7-C, binds to endothelial cells and inhibits their tube formation in culture. In this study, we screened 12 synthetic peptides, covering the fibulin-globular domain of Fbln7-C, to identify active sites for endothelial cell adhesion and in vitro antiangiogenic activity. Three peptides, fc10, fc11, and fc12, promoted Human Umbilical Vein Endothelial Cells (HUVECs) adhesion, and the morphology of HUVECs on fc10 was similar to that on Fbln7-C. EDTA and the anti-integrin ß1 function-blocking antibody inhibited HUVECs adhesion to both fc10 and fc12, and heparin inhibited HUVECs adhesion to both fc11 and fc12. fc10 and fc11 inhibited HUVECs tube formation. Our results suggest that three peptides from Fbln7-C are biologically active for endothelial cell adhesion and disrupt the tube formation, suggesting a potential therapeutic use of these peptides for angiogenesis-related diseases. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 184-195, 2016.
RESUMO
Peptide-polysaccharide matrices can mimic extracellular matrix structure and function and are useful for tissue and cell engineering. The spacer between the peptide and the polysaccharide is important for both peptide conformation and the interaction between the peptide and receptors. Here, the effect of a spacer on the biological activity of peptide-polysaccharide matrices using various lengths of spacers consisting of glycine, ß-alanine, and ε-aminocaproic acid has been examined. Active laminin-derived peptides, including a syndecan-binding peptide (AG73: RKRLQVQLSIRT), an integrin αvß3-binding peptide (A99a: ALRGDN), and an integrin α6ß1-binding peptide (A2G10: SYWYRIEASRTG), were used as the peptide ligands and chitosan was used as a polysaccharide matrix. The spacers did not influence the biological activity of the AG73-chitosan matrix. In contrast, the integrin-binding peptide-chitosan matrices showed spacer-dependent activity. Hydrophobic spacers enhanced the cell attachment activity of the A99a-chitosan matrix. A four-glycine spacer showed the strongest effect for the biological activity of the A2G10-chitosan matrix. These results suggested that spacer-optimization for each peptide is important for designing effective peptide-polysaccharide matrices. © 2015 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 512-520, 2016.
Assuntos
Quitosana/química , Integrina alfaVbeta3/química , Peptídeos/química , Peptídeos/síntese química , HumanosRESUMO
Crosstalk of different integrins, which bind to distinct types of extracellular matrix proteins, promotes specific functions. This crosstalk has not been investigated in depth. Previously, we demonstrated that integrin-syndecan crosstalk accelerated cell adhesion. Here, we evaluated the crosstalk of two different integrins using mixed peptide-polysaccharide (chitosan or alginate) matrices. Two different integrin binding peptides, FIB1 (integrin αvß3), EF1zz (integrin α2ß1), and 531 (integrin α3ß1), were mixed in various molar ratios (9:1, 4:1, 1:1) and conjugated on a polysaccharide matrix. The mixture of FIB1/EF1zz- and FIB1/531-polysaccharide matrices did not show any difference in human dermal fibroblast (HDF) adhesion against the mono polysaccharide matrices. Interestingly, the EF1zz/531-polysaccharide matrix (molar ratio = 1:4) exhibited significantly decreased cell adhesion, but other EF1zz/531-polysaccharide matrices did not show any difference. When we examined the signal transduction of the EF1zz/531(1:4), Y397 phosphorylation of FAK significantly decreased but Y514 phosphorylation of Src did not exhibit any differences. Further investigation revealed that this suppression was mediated by PI3K signaling through the activation of integrin, and PKA signaling modulated suppression of HDF attachment. These findings suggest that a mixed peptide-polysaccharide matrix using receptor specific ligands can regulate cellular functions through receptor-specific crosstalk and is a useful approach to understand receptor specific crosstalk.
Assuntos
Fibroblastos/citologia , Integrinas/metabolismo , Peptídeos/farmacologia , Polissacarídeos/farmacologia , Sequência de Aminoácidos , Anticorpos Bloqueadores/farmacologia , Adesão Celular/efeitos dos fármacos , Quitosana/farmacologia , Derme/citologia , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Proteína-Tirosina Quinases de Adesão Focal/metabolismo , Humanos , Immunoblotting , Dados de Sequência Molecular , Peptídeos/química , Fosforilação/efeitos dos fármacos , Quinases da Família src/metabolismoRESUMO
An amyloidogenic LAM-L peptide (AASIKVAVSADR, all-L configuration) derived from laminin promoted cell adhesion, neurite outgrowth, and angiogenesis. Here, we prepared novel matrices using double-stranded DNA and the LAM-L peptide. Double-stranded DNA promoted aggregation of amyloid-like fibrils and generated a LAM-L/DNA matrix through electrostatic interactions between the phosphate groups of DNA and the amino groups of LAM-L. This formation of peptide/DNA matrix depends on the Ile-Lys-Val-Ala-Val (IKVAV) sequence in the peptide, since LAM-RM peptide (AASVVIAKSADR), which is scrambled peptide of LAM-L, did not form a matrix with DNA. Further, LAM-D (all-D configuration of LAM-L), which forms amyloid-like fibrils and promotes similar biological activities as LAM-L, did not form amyloid-like fibrils with DNA, suggesting that DNA selectively interacts with the L-configured peptide. Moreover, the LAM-L/DNA matrices showed stronger cell attachment activity compared with LAM-L alone, suggesting the LAM-L/DNA matrices have potential for use as a novel biomaterial in tissue engineering.
Assuntos
Amiloide/química , DNA/química , Peptídeos/química , Agregados Proteicos , Sequência de Aminoácidos , Adesão Celular , Linhagem Celular Tumoral , Vermelho Congo , DNA/ultraestrutura , Eletroforese em Gel de Ágar , Humanos , Dados de Sequência Molecular , Espectrofotometria Ultravioleta , Coloração e Rotulagem , EstereoisomerismoRESUMO
Lutheran (Lu), an immunoglobulin superfamily transmembrane receptor, is also known as basal cell adhesion molecule (B-CAM). Lu/B-CAM is a specific receptor for laminin α5, a subunit of laminin-511 (LM-511) that is a major component of basement membranes in various tissues. Our previous study showed that Lu/B-CAM was cleaved by MT1-MMP and released from cell surfaces. In this study we examined the soluble Lu/B-CAM in culture media and in plasma of mice bearing HuH-7 hepatocellular carcinoma (HCC) cells and patients with HCC. Two HCC cell lines, HepG2 and HuH-7, released Lu/B-CAM into the culture media. Although Lu/B-CAM was cleaved by MT1-MMP in HuH-7 cells, HepG2 cells released Lu/B-CAM in a MMP-independent manner. The concentration of Lu/B-CAM released into mouse plasma correlated with tumor size. Moreover the soluble Lu/B-CAM in plasma of HCC patients was significantly decreased after resection of the tumor. Immunohistochemical studies showed that although the expression of Lu/B-CAM was observed in most HCCs, MT1-MMP was not always expressed in tumor tissues, suggesting that a part of Lu/B-CAM in plasma of HCC patients was also released in a MMP-independent manner. In vitro studies showed that the soluble Lu/B-CAM released from HCC cells bound to LM-511. Moreover the soluble Lu/B-CAM influenced cell migration on LM-511. These results suggest that soluble Lu/B-CAM serves as not only a novel marker for HCC but also a modulator in tumor progression.
Assuntos
Biomarcadores Tumorais/sangue , Carcinoma Hepatocelular/metabolismo , Moléculas de Adesão Celular/metabolismo , Movimento Celular , Proliferação de Células , Laminina/metabolismo , Neoplasias Hepáticas/metabolismo , Sistema do Grupo Sanguíneo Lutheran/metabolismo , Adulto , Idoso , Animais , Western Blotting , Carcinoma Hepatocelular/patologia , Carcinoma Hepatocelular/cirurgia , Feminino , Citometria de Fluxo , Glicosilação , Humanos , Técnicas Imunoenzimáticas , Imunoprecipitação , Técnicas In Vitro , Neoplasias Hepáticas/patologia , Neoplasias Hepáticas/cirurgia , Masculino , Metaloproteinase 14 da Matriz/química , Metaloproteinase 14 da Matriz/genética , Metaloproteinase 14 da Matriz/metabolismo , Camundongos , Camundongos Nus , Pessoa de Meia-Idade , Domínios e Motivos de Interação entre Proteínas , RNA Interferente Pequeno/genética , Células Tumorais CultivadasRESUMO
Laminins, major components of basement membrane, consist of three different subunits, α, ß, and γ chains, and so far, five α, three ß, and three γ chains have been identified. We have constructed synthetic peptide libraries derived from the laminin sequences and identified various cell-adhesive peptides. Ten active peptides from the laminin α chain sequences (α1-α5) were found to promote integrin-mediated cell adhesion. Previously, we found fourteen cell-adhesive peptides from the ß1 chain sequence but their receptors have not been analyzed. Here, we expanded the synthetic peptide library to add peptides from the short arm regions of the laminin ß2 and ß3 chains and screened for integrin-binding peptides. Twenty-seven peptides promoted human dermal fibroblast (HDF) attachment in a peptide-coated plate assay. The morphological appearance of HDFs on the peptide-coated plates differed depending on the peptides. B34 (REKYYYAVYDMV, mouse laminin ß1 chain, 255-266), B67 (IPYSMEYEILIRY, mouse laminin ß1 chain, 604-616), B2-105 (APNFWNFTSGRG, mouse laminin ß2 chain, 1081-1092), and B3-19 (GHLTGGKVQLNL, mouse laminin ß3 chain, 182-193) promoted HDF spreading and HDF attachment was inhibited by EDTA, suggesting that the peptides interact with integrins. Immunostaining analyses revealed that B67 induced well-organized actin stress fibers and focal contacts containing vinculin, however, B34, B2-105, and B3-19 did not exhibit stress fiber formation or focal contacts. The inhibition assay using anti-integrin antibodies indicated that B67 interacts with α3, α6, and ß1 integrins, and B34 and B3-19 interact with ß1 integrin. Based on adhesion analysis of peptides modified with an alanine scan and on switching analysis with the homologous inactive sequence B2-64 (LPRAMDYDLLLRW, mouse laminin ß2 chain, 618-630), the Glu(8) residue in the B67 peptide was critical for HDF adhesion. These findings are useful for identifying an integrin binding motif. The B67 peptide has potential for use as a molecular probe for integrins.