title: Effect of hydrogel elasticity and ephrinB2-immobilized manner on Runx2 expression of human mesenchymal stem cells.
abstract: The objective of this study is to design the manner of ephrinB2 immobilized onto polyacrylamide (PAAm) hydrogels with varied elasticity and evaluate the effect of hydrogels elasticity and the immobilized manner of ephrinB2 on the Runx2 expression of human mesenchymal stem cells (hMSC). The PAAm hydrogels were prepared by the radical polymerization of acrylamide (AAm), and N,N'-methylenebisacrylamide (BIS). By changing the BIS concentration, the elasticity of PAAm hydrogels changed from 1 to 70kPa. For the bio-specific immobilization of ephrinB2, a chimeric protein of ephrinB2 and Fc domain was immobilized onto protein A-conjugated PAAm hydrogels by making use of the bio-specific interaction between the Fc domain and protein A. When hMSC were cultured on the ephrinB2-immobilized PAAm hydrogels with varied elasticity, the morphology of hMSC was of cuboidal shape on the PAAm hydrogels immobilized with ephrinB2 compared with non-conjugated ones, irrespective of the hydrogels elasticity. The bio-specific immobilization of ephrinB2 enhanced the level of Runx2 expression. The expression level was significantly high for the hydrogels of 3.6 and 5.9kPa elasticity with bio-specific immobilization of ephrinB2 compared with other hydrogels with the same elasticity. The hydrogels showed a significantly down-regulated RhoA activity. It is concluded that the Runx2 expression of hMSC is synergistically influenced by the hydrogels elasticity and their immobilized manner of ephrinB2 immobilized.
  
  
  
  Differentiation fate of mesenchymal stem cells (MSC) is modified by biochemical and biophysical factors, such as elasticity and signal proteins. However, there are few experiments about combinations of them. In this study, to evaluate the synergistic effect of them on cell properties of MSC, we established to design the manner of Eph signal ligand, ephrinB2, immobilized onto polyacrylamide hydrogels with varied elasticity. The gene expression level of an osteogenic maker, Runx2, was enhanced by the immobilized manner, and significantly enhanced for the hydrogels of around 4kPa elasticity with bio-specific immobilization of ephrinB2. This is the novel report describing to demonstrate that the Runx2 expression of MSC is synergistically influenced by the hydrogels elasticity and their manner of ephrinB2 immobilized.
authors.affiliation: Department of Biomaterials, Field of Tissue Engineering, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan.
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Toda
authors.affiliation: Department of Biomaterials, Field of Tissue Engineering, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan.
authors.forename: Masaya
authors.initials: M
authors.lastname: Yamamoto
authors.affiliation: Division of Applied Chemistry, Graduate School of Engineering, Osaka University, Osaka, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Uyama
authors.affiliation: Department of Biomaterials, Field of Tissue Engineering, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan. Electronic address: yasuhiko@frontier.kyoto-u.ac.jp.
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Tabata
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000818:Animals; D002461:Cell Line, Transformed; D050659:Core Binding Factor Alpha 1 Subunit / Q000096:biosynthesis*; D004548:Elasticity; D036388:Ephrin-B2 / Q000737:chemistry*; D005786:Gene Expression Regulation; D006801:Humans; D020100:Hydrogels / Q000737:chemistry*; D055767:Immobilized Proteins / Q000737:chemistry*; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D000099166:Polyacrylamides
chemical_list: D000180:Acrylic Resins; D050659:Core Binding Factor Alpha 1 Subunit; D036388:Ephrin-B2; D020100:Hydrogels; D055767:Immobilized Proteins; D000099166:Polyacrylamides; C000601239:EFNB2 protein, human; C493709:RUNX2 protein, human
keywords: Elasticity; Ephrinb2; Human mesenchymal stem cell (hMSC); Runx2 expression; Synergistic effect