chondroitin-sulfates and arginyl-glycyl-aspartic-acid

To review the research progress of promoting the bone formation at early stage by components of the extracellular matrix (ECM).. Recent literature concerning the influence of these components on new bone formation and bone/implant contact was extensively reviewed and summarized.. Coating of titanium or hydroxyapatite implants with organic components of the ECM (such as collagen type I, chondroitin sulfate, and Arg-Gly-Asp peptide) offers great potential to improve new bone formation and enhance bone/implant contact, which in turn will shorten recovery time and improve implant stability.. The increasing knowledge about the role of the ECM for recruitment, proliferation, differentiation of cells, and regeneration of tissue will eventually deal to the creating of an artificial EGM on the implant that could allow a defined adjustment of the required properties to support the healing process.

Topics: Animals; Bone Regeneration; Chondroitin Sulfates; Coated Materials, Biocompatible; Collagen Type I; Extracellular Matrix; Humans; Oligopeptides; Osseointegration; Prostheses and Implants; Surface Properties; Tissue Engineering; Titanium

The glycocalyx is thought to perform a potent, but not yet defined function in cellular adhesion and signaling. Since 95% of cancer cells have altered glycocalyx structure, this role can be especially important in cancer development and metastasis. The glycocalyx layer of cancer cells directly influences cancer progression, involving the complicated kinetic process of cellular adhesion at various levels. In the present work, we investigated the effect of enzymatic digestion of specific glycocalyx components on cancer cell adhesion to RGD (arginine-glycine-aspartic acid) peptide motif displaying surfaces. High resolution kinetic data of cell adhesion was recorded by the surface sensitive label-free resonant waveguide grating (RWG) biosensor, supported by fluorescent staining of the cells and cell surface charge measurements. We found that intense removal of chondroitin sulfate (CS) and dermatan sulfate chains by chondroitinase ABC reduced the speed and decreased the strength of adhesion of HeLa cells. In contrast, mild digestion of glycocalyx resulted in faster and stronger adhesion. Control experiments on a healthy and another cancer cell line were also conducted, and the discrepancies were analysed. We developed a biophysical model which was fitted to the kinetic data of HeLa cells. Our analysis suggests that the rate of integrin receptor transport to the adhesion zone and integrin-RGD binding is strongly influenced by the presence of glycocalyx components, but the integrin-RGD dissociation is not. Moreover, based on the kinetic data we calculated the dependence of the dissociation constant of integrin-RGD binding on the enzyme concentration. We also determined the dissociation constant using a 2D receptor binding model based on saturation level static data recorded at surfaces with tuned RGD densities. We analyzed the discrepancies of the kinetic and static dissociation constants, further illuminating the role of cancer cell glycocalyx during the adhesion process. Altogether, our experimental results and modelling demonstrated that the chondroitin sulfate and dermatan sulfate chains of glycocalyx have an important regulatory function during the cellular adhesion process, mainly controlling the kinetics of integrin transport and integrin assembly into mature adhesion sites. Our results potentially open the way for novel type of cancer treatments affecting these regulatory mechanisms of cellular glycocalyx.

Topics: Biophysical Phenomena; Biosensing Techniques; Cell Adhesion; Chondroitin ABC Lyase; Chondroitin Sulfates; Dermatan Sulfate; Focal Adhesions; Glycocalyx; HeLa Cells; Humans; Integrins; Kinetics; Models, Biological; Neoplasms; Oligopeptides

The aim of the present study was to test the hypothesis that peri-implant bone formation can be improved by modifying dual acid-etched (DAE) implant surfaces using organic coatings that enhance cell adhesion and osteogenic differentiation.. Ten adult female foxhounds received experimental titanium implants in the mandible 3 months after removal of all premolar teeth. Six types of implants were evaluated in each animal: (i) implants with a machined surface (MS), (ii) implants with a DAE surface topography, (iii) implants with an acid-etched surface coated with RGD peptides, (iv) implants with an acid-etched surface coated with collagen I, (v) implants with an acid-etched surface coated with collagen I and chondroitin sulphate (CS), (vi) implants with an acid-etched surface coated with collagen I and CS and recombinant human bone morphogenetic protein-2. Peri-implant bone regeneration was assessed by histomorphometry after 1 and 3 months in five dogs each by measuring bone implant contact (BIC) and the bone volume density (BVD) of the newly formed peri-implant bone.. After 1 month, mean BIC was significantly higher in the coated implants group than in the MS group. There was no significant difference when mean BIC in the DAE group was compared with implants with any of the organic coatings, but the difference was significant when compared with the MS implants. Differences in mean BVD value did not reach significance between any of the surfaces. After 3 months, the same held true for the mean BIC of all the groups except for Coll I. Mean volume density of the newly formed bone was higher in all the surface modifications, albeit without statistical significance.. It is concluded that with the exception of Coll I, the tested organic surface coatings on DAE surfaces did not improve peri-implant bone formation when compared with the DAE surfaces but enhanced BIC when compared with the MSs.

Topics: Acid Etching, Dental; Animals; Bone Density; Bone Morphogenetic Protein 2; Bone Morphogenetic Proteins; Cell Adhesion; Chondroitin Sulfates; Coated Materials, Biocompatible; Collagen Type I; Dental Implants; Dogs; Female; Humans; Implants, Experimental; Oligopeptides; Osseointegration; Recombinant Proteins; Surface Properties; Time Factors; Titanium; Transforming Growth Factor beta

Coating of orthopaedic implants with extracellular bone matrix components was performed to enhance bone healing. Titanium pins of 0.8mm diameter were coated with type I collagen (Ti/Coll), RGD peptide (Ti/RGD) or type I collagen and chondroitin sulfate (Ti/Coll/CS). Uncoated pins (Ti) served as control. The pins were inserted as intramedullary nails into the tibia of male adult Wistar rats. Six specimens of each group were retrieved at 4, 7, 14 and 28 days. All implants healed uneventfully without adverse reactions. ED 1-positive macrophages appeared in higher numbers around Ti/RGD at day 4 and around Ti at day 14 after implantation (p < 0.05). TRAP-positive osteoclasts and precursors were abundant around Ti/Coll/CS at day 7 (p < 0.05). A significant increase in osteopontin-positive osteoblasts was seen around Ti/Coll/CS implants at days 7 and 14, and around Ti/RGD at day 14 (p < 0.05). At day 28, 62% of Ti, 76% of Ti/Coll, 85%* of Ti/RGD and 89%* of Ti/CoIl/CS (*p < 0.05) implants were covered with newly formed lamellar bone. The addition of extracellular matrix components significantly enhances bone remodelling in the early stages of bone healing around Ti implants, eventually leading to increased new bone formation at the implant surface after 4 weeks.

Topics: Animals; Bone Substitutes; Chondroitin Sulfates; Collagen; Immunohistochemistry; Implants, Experimental; Male; Materials Testing; Microscopy, Atomic Force; Oligopeptides; Osteoblasts; Rats; Rats, Wistar; Tibia; Titanium

CD97, a membrane protein expressed at high levels on inflammatory cells and some carcinomas, is a member of the adhesion G protein-coupled receptor family, whose members have bipartite structures consisting of an extracellular peptide containing adhesion motifs noncovalently coupled to a class B 7-transmembrane domain. CD97alpha, the extracellular domain of CD97, contains 3 to 5 fibrillin class 1 epidermal growth factor (EGF)-like repeats, an Arg-Gly-Asp (RGD) tripeptide, and a mucin stalk. We show here that CD97alpha promotes angiogenesis in vivo as demonstrated with purified protein in a directed in vivo angiogenesis assay (DIVAA) and by enhanced vascularization of developing tumors expressing CD97. These data suggest that CD97 can contribute to angiogenesis associated with inflammation and tumor progression. Strong integrin alpha5beta1 interactions with CD97 have been identified, but alpha v beta3 also contributes to cell attachment. Furthermore, soluble CD97 acts as a potent chemoattractant for migration and invasion of human umbilical vein endothelial cells (HUVECs), and this function is integrin dependent. CD97 EGF-like repeat 4 is known to bind chondroitin sulfate. It was found that coengagement of alpha5beta1 and chondroitotin sulfate proteoglycan by CD97 synergistically initiates endothelial cell invasion. Integrin alpha5beta1 is the first high-affinity cellular counterreceptor that has been identified for a member within this family of adhesion receptors.

Topics: Animals; Antigens, CD; Cell Adhesion; Chondroitin Sulfates; Endothelium, Vascular; Epidermal Growth Factor; HT29 Cells; Humans; Integrin alpha5beta1; Integrin alphaVbeta3; Membrane Glycoproteins; Mice; Neoplasms; Neovascularization, Physiologic; NIH 3T3 Cells; Oligopeptides; Phenotype; Protein Structure, Tertiary; Rats; Receptors, G-Protein-Coupled; Umbilical Veins

Based on the hypothesis that the attachment of neuroectodermal cells to thrombospondin-1 (TSP-1) may affect tumor spread and play a role in the anti-tumor effects of retinoic acid, we investigated the expression of TSP-1 in these cells in situ and the effect of retinoic acid on the morphology of TSP-1-adherent neuroblastoma (SK-N-SH) and malignant astrocytoma (U-251MG) cells in vitro. TSP-1-adherent SK-N-SH cells demonstrated process outgrowth, with further neuronal differentiation after retinoic acid treatment, consistent with the in situ studies showing that TSP-1 expression occurs in a differentiation-specific manner in neuroblastic tumors. TSP-1-adherent U-251MG cells failed to spread; however, after retinoic acid treatment the cells demonstrated broad lamellipodia containing radial actin fibers and organization of integrins alpha3beta1 and alpha5beta1 in clusters in lamellipodia and filopodia. The attachment of both SK-N-SH and U-251MG cells to TSP-1 was found to be mediated by heparan sulfate proteoglycans, integrins, and the CLESH-1 adhesion domain first identified in CD36. Heparin and heparitinase treatment inhibited TSP-1 attachment. Integrins alpha3beta1 and alpha5beta1 mediated TSP-1 attachment of SK-N-SH cells, and integrins alpha3beta1, alpha5beta1, and alphavbeta3 mediated TSP-1 attachment of U-251MG cells. Attachment was dependent on the RGD sequence which is located in the carboxy-terminus of TSP-1. Treatment with a pharmacologic dosage of retinoic acid altered the TSP-1 cell adhesion mechanism in both cell lines in that neither heparin nor micromolar concentrations of the RGD peptide inhibited attachment; after treatment, attachment was inhibited by the CSVTCG peptide located in the type I repeat domain of TSP-1 and a recombinant adhesion domain (CLESH-1) from CD36. Expression of CD36 was found in the retinoic acid-treated U-251MG cells. These data indicate that neuroectodermally derived cells utilize several mechanisms to attach to TSP-1, and these are differentially modulated by treatment with retinoic acid. These data also suggest that the CSVTCG sequence of TSP-1 modulates or directs cytoskeletal organization in neuroblastoma and astrocytoma cells.

Topics: Astrocytes; Astrocytoma; Brain; CD36 Antigens; Cell Adhesion; Cell Differentiation; Chondroitin ABC Lyase; Chondroitin Sulfates; Cytoskeleton; Endothelium; Ganglioneuroblastoma; Ganglioneuroma; Glioblastoma; Heparin; Humans; Integrin alpha3beta1; Integrins; Neuroblastoma; Neurons; Oligopeptides; Peptide Fragments; Polysaccharide-Lyases; Receptors, Fibronectin; Recombinant Proteins; Thrombospondin 1; Tretinoin; Tumor Cells, Cultured

Composite dermal-epidermal skin substitutes rely on a firm attachment of human keratinocytes (HK) to the dermal substrate for graft survival on the wound. An in vitro study was performed assessing whether the addition of matrix peptides to the dermal substrate effected the epithelial thickness. Cultured grafts were made by attaching HK to the external surface of a collagen-chondroitin 6-sulfate (GAG) membrane and inoculating human fibroblasts (HF) internally. If the matrix peptide (RGD Peptide) was added to the collagen-GAG membrane prior to placement of the HK and HF, the resultant epithelial layer at the end of the normal 4-day culture period was significantly thicker (19.7 +/- 0.9 microns versus 13.5 +/- 1.0 microns). Subjectively, the HF content was also greater on the peptide-treated grafts. When HF were not placed on the cultured graft, i.e., only collagen-GAG membrane, RGD peptide, and HK, the resultant epithelial thickness was even greater (28.3 +/- 1.0 microns). These data suggest that addition of matrix peptides, which increase cell attachment to the dermal substrate, may prove effective in the improvement of this cultured composite dermal-epidermal skin substitute.

Topics: Bandages; Biological Dressings; Cell Adhesion; Cells, Cultured; Chondroitin Sulfates; Collagen; Epithelial Cells; Fibroblasts; Humans; Keratinocytes; Membranes, Artificial; Oligopeptides