title: Molecular composition of GAG-collagen I multilayers affects remodeling of terminal layers and osteogenic differentiation of adipose-derived stem cells.
abstract: The effect of molecular composition of multilayers, by pairing type I collagen (Col I) with either hyaluronic acid (HA) or chondroitin sulfate (CS) was studied regarding the osteogenic differentiation of adhering human adipose-derived stem cells (hADSCs). Polyelectrolyte multilayer (PEM) formation was based primarily on ion pairing and on additional intrinsic cross-linking through imine bond formation with Col I replacing native by oxidized HA (oHA) or CS (oCS). Significant amounts of Col I fibrils were found on both native and oxidized CS-based PEMs, resulting in higher water contact angles and surface potential under physiological condition, while much less organized Col I was detected in either HA-based multilayers, which were more hydrophilic and negatively charged. An important finding was that hADSCs remodeled Col I at the terminal layers of PEMs by mechanical reorganization and pericellular proteolytic degradation, being more pronounced on CS-based PEMs. This was in accordance with the higher quantity of Col I deposition in this system, accompanied by more cell spreading, focal adhesions (FA) formation and significant α2β1 integrin recruitment compared to HA-based PEMs. Both CS-based PEMs caused also an increased fibronectin (FN) secretion and cell growth. Furthermore, significant calcium phosphate deposition, enhanced ALP, Col I and Runx2 expression were observed in hADSCs on CS-based PEMs, particularly on oCS-containing one. Overall, multilayer composition can be used to direct cell-matrix interactions, and hence stem cell fates showing for the first time that PEMs made of biogenic polyelectrolytes undergo significant remodeling of terminal protein layers, which seems to enable cells to form a more adequate extracellular matrix-like environment.
  
  
  
  Natural polymer derived polyelectrolyte multilayers (PEMs) have been recently applied to adjust biomaterials to meet specific tissue demands. However, the effect of molecular composition of multilayers on both surface properties and cellular response, especially the fate of human adipose derived stem cells (hADSCs) upon osteogenic differentiation has not been studied extensively, yet. In addition, no studies exist that investigate a potential cell-dependent remodeling of PEMs made of extracellular matrix (ECM) components like collagens and glycosaminoglycans (GAGs). Furthermore, there is no knowledge whether the ability of cells to remodel PEM components may provide an added value regarding cell growth and differentiation. Finally, it has not been explored yet, how intrinsic cross-linking of ECM derived polyelectrolytes that improve the stability of PEMs will affect the differentiation potential of hADSCs. The current work aims to address these questions and found that the type of GAG has a strong effect on properties of multilayers and osteogenic differentiation of hADSCs. Additionally, we also show for the first time that PEMs made of biogenic polyelectrolytes undergo significant remodeling of terminal layers as completely new finding, which allows cells to form an ECM-like environment supporting differentiation upon osteogenic lineage. The finding of this work may open new avenues of application of PEM systems made by layer by layer (LbL) technique in tissue engineering and regenerative medicine.
authors.affiliation: Stem Cell Research and Cellular Therapy Center, Affiliated Hospital of Guangdong Medical University, Renmin Dadao Road 57, Xiashan District, Zhanjiang 524001, China; Biomedical Materials Group, Martin Luther University Halle-Wittenberg, Heinrich-Damerow-Strasse 4, Halle (Saale) 06120, Germany. Electronic address: mingyan985927@163.com.
authors.forename: Mingyan
authors.initials: M
authors.lastname: Zhao
authors.affiliation: Institut for Bioengineering of Catalonia, Baldiri Reixac, 10-12, Barcelona 08028, Spain; ICREA (Institucio Catalana de Recerca i Estudis Avancats), Barcelona 08010, Spain. Electronic address: galtankov@ibecbarcelona.eu.
authors.forename: George
authors.initials: G
authors.lastname: Altankov
authors.affiliation: Department of Anatomy and Cell Biology, Faculty of Medicine, Martin Luther University Halle-Wittenberg, Große Steinstraße 52, Halle (Saale) 06108, Germany. Electronic address: urszula.grabiec@medizin.uni-halle.de.
authors.forename: Urszula
authors.initials: U
authors.lastname: Grabiec
authors.affiliation: Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow, UK. Electronic address: m.bennett.1@research.gla.ac.uk.
authors.forename: Mark
authors.initials: M
authors.lastname: Bennett
authors.affiliation: Division of Biomedical Engineering, School of Engineering, University of Glasgow, Glasgow, UK. Electronic address: Manuel.Salmeron-Sanchez@glasgow.ac.uk.
authors.forename: Manuel
authors.initials: M
authors.lastname: Salmeron-Sanchez
authors.affiliation: Department of Anatomy and Cell Biology, Faculty of Medicine, Martin Luther University Halle-Wittenberg, Große Steinstraße 52, Halle (Saale) 06108, Germany. Electronic address: faramarz.dehghani@medizin.uni-halle.de.
authors.forename: Faramarz
authors.initials: F
authors.lastname: Dehghani
authors.affiliation: Biomedical Materials Group, Martin Luther University Halle-Wittenberg, Heinrich-Damerow-Strasse 4, Halle (Saale) 06120, Germany. Electronic address: thomas.groth@pharmazie.uni-halle.de.
authors.forename: Thomas
authors.initials: T
authors.lastname: Groth
mesh_terms: D000273:Adipose Tissue / Q000166:cytology*; D000469:Alkaline Phosphatase / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism; D002448:Cell Adhesion; D002454:Cell Differentiation; D049109:Cell Proliferation; D002478:Cells, Cultured; D024042:Collagen Type I / Q000737:chemistry*; D004573:Electrolytes / Q000737:chemistry; D006025:Glycosaminoglycans / Q000737:chemistry*; D006801:Humans; D038982:Integrin alpha2beta1 / Q000378:metabolism; D010012:Osteogenesis; D059748:Proteolysis; D013234:Stem Cells / Q000166:cytology*; D013499:Surface Properties
chemical_list: D015415:Biomarkers; D024042:Collagen Type I; D004573:Electrolytes; D006025:Glycosaminoglycans; D038982:Integrin alpha2beta1; D000469:Alkaline Phosphatase
keywords: Collagen reorganization; Glycosaminoglycans; Layer-by-layer technique; Mesenchymal stem cells; Osteogenic differentiation