title: Enhanced articular cartilage by human mesenchymal stem cells in enzymatically mediated transiently RGDS-functionalized collagen-mimetic hydrogels.
abstract: Recapitulation of the articular cartilage microenvironment for regenerative medicine applications faces significant challenges due to the complex and dynamic biochemical and biomechanical nature of native tissue. Towards the goal of biomaterial designs that enable the temporal presentation of bioactive sequences, recombinant bacterial collagens such as Streptococcal collagen-like 2 (Scl2) proteins can be employed to incorporate multiple specific bioactive and biodegradable peptide motifs into a single construct. Here, we first modified the backbone of Scl2 with glycosaminoglycan-binding peptides and cross-linked the modified Scl2 into hydrogels via matrix metalloproteinase 7 (MMP7)-cleavable or non-cleavable scrambled peptides. The cross-linkers were further functionalized with a tethered RGDS peptide creating a system whereby the release from an MMP7-cleavable hydrogel could be compared to a system where release is not possible. The release of the RGDS peptide from the degradable hydrogels led to significantly enhanced expression of collagen type II (3.9-fold increase), aggrecan (7.6-fold increase), and SOX9 (5.2-fold increase) by human mesenchymal stem cells (hMSCs) undergoing chondrogenesis, as well as greater extracellular matrix accumulation compared to non-degradable hydrogels (collagen type II; 3.2-fold increase, aggrecan; 4-fold increase, SOX9; 2.8-fold increase). Hydrogels containing a low concentration of the RGDS peptide displayed significantly decreased collagen type I and X gene expression profiles, suggesting a major advantage over either hydrogels functionalized with a higher RGDS peptide concentration, or non-degradable hydrogels, in promoting an articular cartilage phenotype. These highly versatile Scl2 hydrogels can be further manipulated to improve specific elements of the chondrogenic response by hMSCs, through the introduction of additional bioactive and/or biodegradable motifs. As such, these hydrogels have the possibility to be used for other applications in tissue engineering.
  
  
  
  Recapitulating aspects of the native tissue biochemical microenvironment faces significant challenges in regenerative medicine and tissue engineering due to the complex and dynamic nature of the tissue. The ability to take advantage of, mimic, and modulate cell-mediated processes within novel naturally-derived hydrogels is of great interest in the field of biomaterials to generate constructs that more closely resemble the biochemical microenvironment and functions of native biological tissues such as articular cartilage. Towards this goal, the temporal presentation of bioactive sequences such as RGDS on the chondrogenic differentiation of human mesenchymal stem cells is considered important as it has been shown to influence the chondrogenic phenotype. Here, a novel and versatile platform to recreate a high degree of biological complexity is proposed, which could also be applicable to other tissue engineering and regenerative medicine applications.
authors.affiliation: Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom; Department of Bioengineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom; Institute of Biomedical Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom; CSIRO Manufacturing, Bayview Avenue, Clayton, Victoria 3169, Australia; Division of Biomaterials and Regenerative Medicine, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles väg 2, 17177 Stockholm, Sweden.
authors.forename: Paresh A
authors.initials: PA
authors.lastname: Parmar
authors.affiliation: Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom; Department of Bioengineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom; Institute of Biomedical Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: St-Pierre
authors.affiliation: Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom; Department of Bioengineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom; Institute of Biomedical Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.
authors.forename: Lesley W
authors.initials: LW
authors.lastname: Chow
authors.affiliation: Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom; Department of Bioengineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom; Institute of Biomedical Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom.
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Spicer
authors.affiliation: CSIRO Manufacturing, Bayview Avenue, Clayton, Victoria 3169, Australia.
authors.forename: Violet
authors.initials: V
authors.lastname: Stoichevska
authors.affiliation: CSIRO Manufacturing, Bayview Avenue, Clayton, Victoria 3169, Australia.
authors.forename: Yong Y
authors.initials: YY
authors.lastname: Peng
authors.affiliation: CSIRO Manufacturing, Bayview Avenue, Clayton, Victoria 3169, Australia.
authors.forename: Jerome A
authors.initials: JA
authors.lastname: Werkmeister
authors.affiliation: CSIRO Manufacturing, Bayview Avenue, Clayton, Victoria 3169, Australia.
authors.forename: John A M
authors.initials: JAM
authors.lastname: Ramshaw
authors.affiliation: Department of Materials, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom; Department of Bioengineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom; Institute of Biomedical Engineering, Imperial College London, Exhibition Road, London SW7 2AZ, United Kingdom; Division of Biomaterials and Regenerative Medicine, Department of Medical Biochemistry and Biophysics, Karolinska Institutet, Scheeles väg 2, 17177 Stockholm, Sweden. Electronic address: m.stevens@imperial.ac.uk.
authors.forename: Molly M
authors.initials: MM
authors.lastname: Stevens
mesh_terms: D001426:Bacterial Proteins / Q000378:metabolism; D040761:Biomimetic Materials / Q000494:pharmacology*; D002358:Cartilage, Articular / Q000166:cytology*; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D020219:Chondrogenesis / Q000187:drug effects; D003094:Collagen / Q000378:metabolism / Q000494:pharmacology*; D019245:Compressive Strength; D004247:DNA / Q000378:metabolism; D005109:Extracellular Matrix / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D006025:Glycosaminoglycans / Q000378:metabolism; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000494:pharmacology*; D007700:Kinetics; D020783:Matrix Metalloproteinase 7 / Q000378:metabolism*; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D009842:Oligopeptides / Q000494:pharmacology*
chemical_list: D001426:Bacterial Proteins; D006025:Glycosaminoglycans; D009842:Oligopeptides; C423453:Scl2 protein, Streptococcus; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D003094:Collagen; D004247:DNA; C046617:arginyl-glycyl-aspartyl-serine; D020783:Matrix Metalloproteinase 7
keywords: Biodegradation; Biomimetic material; Cartilage tissue engineering; Hydrogel; Mesenchymal stem cell; RGDS