title: Effects of substrate stiffness and cell-cell contact on mesenchymal stem cell differentiation.
abstract: The mechanical properties of the microenvironment and direct contact-mediated cell-cell interactions are two variables known to be important in the determination of stem cell differentiation fate, but little is known about the interplay of these cues. Here, we use a micropatterning approach on polyacrylamide gels of tunable stiffnesses to study how homotypic cell-cell contacts and mechanical stiffness affect different stages of osteogenesis of mesenchymal stem cells (MSCs). Nuclear localization of transcription factors associated with osteogenesis depended on substrate stiffness and was independent of the degree of cell-cell contact. However, expression of alkaline phosphatase, an early protein marker for osteogenesis, increased only in cells with both direct contact with neighboring cells and adhesion to stiffer substrates. Finally, mature osteogenesis, as assessed by calcium deposition, was low in micropatterned cells, even on stiff substrates and in multicellular clusters. These results indicate that substrate stiffness and the presence of neighboring cells regulate osteogenesis in MSCs.
authors.affiliation: John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford St, Cambridge, MA 02138, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, Boston, MA 02115, USA.
authors.forename: Angelo S
authors.initials: AS
authors.lastname: Mao
authors.affiliation: Department of Pharmacology, University of Illinois College of Medicine, Chicago, IL 60612, USA.
authors.forename: Jae-Won
authors.initials: JW
authors.lastname: Shin
authors.affiliation: John A. Paulson School of Engineering and Applied Sciences, Harvard University, 29 Oxford St, Cambridge, MA 02138, USA; Wyss Institute for Biologically Inspired Engineering, Harvard University, 3 Blackfan Circle, Boston, MA 02115, USA. Electronic address: mooneyd@seas.harvard.edu.
authors.forename: David J
authors.initials: DJ
authors.lastname: Mooney
mesh_terms: D000180:Acrylic Resins / Q000494:pharmacology*; D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D002448:Cell Adhesion / Q000187:drug effects; D002450:Cell Communication / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D055119:Elastic Modulus; D005353:Fibronectins / Q000378:metabolism; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D010012:Osteogenesis / Q000187:drug effects; D014157:Transcription Factors / Q000378:metabolism
chemical_list: D000180:Acrylic Resins; D005353:Fibronectins; D014157:Transcription Factors; C016680:polyacrylamide gels; D000469:Alkaline Phosphatase
keywords: Differentiation; Mechanical properties; Mesenchymal stem cells; Micropatterning; Osteogenesis