title: Tuning microenvironment modulus and biochemical composition promotes human mesenchymal stem cell tenogenic differentiation.
abstract: Mesenchymal stem cells (MSCs) are promising for the regeneration of tendon and ligament tissues. Toward realizing this potential, microenvironment conditions are needed for promoting robust lineage-specific differentiation into tenocytes/ligament fibroblasts. Here, we utilized a statistical design of experiments approach to examine combinations of matrix modulus, composition, and soluble factors in human MSC tenogenic/ligamentogenic differentiation. Specifically, well-defined poly(ethylene glycol)-based hydrogels were synthesized using thiol-ene chemistry providing a bioinert base for probing cell response to extracellular matrix cues. Monomer concentrations were varied to achieve a range of matrix moduli (E ∼ 10-90 kPa), and different ratios of integrin-binding peptides were incorporated (GFOGER and RGDS for collagen and fibronectin, respectively), mimicking aspects of developing tendon/ligament tissue. A face-centered central composite response surface design was utilized to understand the contributions of these cues to human MSC differentiation in the presence of soluble factors identified to promote tenogenesis/ligamentogenesis (BMP-13 and ascorbic acid). Increasing modulus and collagen mimetic peptide content increased relevant gene expression and protein production or retention (scleraxis, collagen I, tenascin-C). These findings could inform the design of materials for tendon/ligament regeneration. More broadly, the design of experiments enabled efficient data acquisition and analysis, requiring fewer replicates than if each factor had been varied one at a time. This approach can be combined with other stimuli (for example, mechanical stimulation) toward a better mechanistic understanding of differentiation down these challenging lineages.
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, 19716.
authors.forename: Matthew S
authors.initials: MS
authors.lastname: Rehmann
authors.affiliation: Department of Dermatology, School of Medicine, University of California, Davis, California, 95816.
authors.forename: Jesus I
authors.initials: JI
authors.lastname: Luna
authors.affiliation: Department of Dermatology, School of Medicine, University of California, Davis, California, 95816.
authors.forename: Emanual
authors.initials: E
authors.lastname: Maverakis
authors.affiliation: Department of Chemical and Biomolecular Engineering, University of Delaware, Newark, Delaware, 19716.|Department of Materials Science and Engineering, University of Delaware, Newark, Delaware, 19716.
authors.forename: April M
authors.initials: AM
authors.lastname: Kloxin
mesh_terms: D000328:Adult; D001672:Biocompatible Materials / Q000737:chemistry*; D040761:Biomimetic Materials / Q000737:chemistry*; D002454:Cell Differentiation; D002478:Cells, Cultured; D003094:Collagen / Q000737:chemistry; D055119:Elastic Modulus; D005260:Female; D015870:Gene Expression; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D009842:Oligopeptides / Q000737:chemistry; D011092:Polyethylene Glycols / Q000737:chemistry; D012038:Regeneration; D013710:Tendons / Q000166:cytology* / Q000502:physiology; D023822:Tissue Engineering
chemical_list: D001672:Biocompatible Materials; D020100:Hydrogels; D009842:Oligopeptides; D011092:Polyethylene Glycols; C047981:arginyl-glycyl-aspartic acid; D003094:Collagen
keywords: cell microenvironment; design of experiments; hydrogel; mesenchymal stem cell; tendon