title: Temporally degradable collagen-mimetic hydrogels tuned to chondrogenesis of human mesenchymal stem cells.
abstract: Tissue engineering strategies for repairing and regenerating articular cartilage face critical challenges to recapitulate the dynamic and complex biochemical microenvironment of native tissues. One approach to mimic the biochemical complexity of articular cartilage is through the use of recombinant bacterial collagens as they provide a well-defined biological 'blank template' that can be modified to incorporate bioactive and biodegradable peptide sequences within a precisely defined three-dimensional system. We customized the backbone of a Streptococcal collagen-like 2 (Scl2) protein with heparin-binding, integrin-binding, and hyaluronic acid-binding peptide sequences previously shown to modulate chondrogenesis and then cross-linked the recombinant Scl2 protein with a combination of matrix metalloproteinase 7 (MMP7)- and aggrecanase (ADAMTS4)-cleavable peptides at varying ratios to form biodegradable hydrogels with degradation characteristics matching the temporal expression pattern of these enzymes in human mesenchymal stem cells (hMSCs) during chondrogenesis. hMSCs encapsulated within the hydrogels cross-linked with both degradable peptides exhibited enhanced chondrogenic characteristics as demonstrated by gene expression and extracellular matrix deposition compared to the hydrogels cross-linked with a single peptide. Additionally, these combined peptide hydrogels displayed increased MMP7 and ADAMTS4 activities and yet increased compression moduli after 6 weeks, suggesting a positive correlation between the degradation of the hydrogels and the accumulation of matrix by hMSCs undergoing chondrogenesis. Our results suggest that including dual degradation motifs designed to respond to enzymatic activity of hMSCs going through chondrogenic differentiation led to improvements in chondrogenesis. Our hydrogel system demonstrates a bimodal enzymatically degradable biological platform that can mimic native cellular processes in a temporal manner. As such, this novel collagen-mimetic protein, cross-linked via multiple enzymatically degradable peptides, provides a highly adaptable and well defined platform to recapitulate a high degree of biological complexity, which could be applicable to numerous 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.
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: Stacey C
authors.initials: SC
authors.lastname: Skaalure
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: Jean-Philippe
authors.initials: JP
authors.lastname: St-Pierre
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: JA
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. Electronic address: m.stevens@imperial.ac.uk.
authors.forename: Molly M
authors.initials: MM
authors.lastname: Stevens
mesh_terms: D000071121:ADAMTS4 Protein / Q000737:chemistry; D001426:Bacterial Proteins / Q000737:chemistry* / Q000235:genetics; D040761:Biomimetic Materials / Q000737:chemistry* / Q000378:metabolism; D002358:Cartilage, Articular / Q000166:cytology; D002454:Cell Differentiation; D002478:Cells, Cultured; D020219:Chondrogenesis; D003094:Collagen / Q000737:chemistry* / Q000235:genetics / Q000378:metabolism; D003432:Cross-Linking Reagents / Q000737:chemistry; D010450:Endopeptidases / Q000737:chemistry; D005109:Extracellular Matrix / Q000648:ultrastructure; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D020783:Matrix Metalloproteinase 7 / Q000737:chemistry; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D010455:Peptides / Q000737:chemistry; D059748:Proteolysis; D013291:Streptococcus; D023822:Tissue Engineering / Q000379:methods
chemical_list: D001426:Bacterial Proteins; D003432:Cross-Linking Reagents; D010455:Peptides; C423453:Scl2 protein, Streptococcus; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D003094:Collagen; D010450:Endopeptidases; D020783:Matrix Metalloproteinase 7; D000071121:ADAMTS4 Protein; C083641:aggrecanase
keywords: Bacterial collagen; Biodegradation; Biomimetic material; Cartilage tissue engineering; Hydrogel; Mesenchymal stem cell