title: Culturing of mouse and human cells on soft substrates promote the expression of stem cell markers.
abstract: Substrate elasticity is a potent regulator of the cell state. Soft substrates have been shown to promote the homogeneous self-renewal of mouse embryonic stem cells through the down-regulation of cell-matrix tractions. We therefore investigated whether soft substrates promote the reprogramming of somatic cells into induced pluripotent stem (iPS) cells. After retroviral infection with five factors, Oct3/4, Klf4, Sox2, Lin28 and Nanog, mouse embryonic fibroblasts (MEFs) were cultured on several artificial substrates of varying elasticity and examined for the expression of pluripotency genes. When MEFs were cultured on soft (<0.1 kPa) polyacrylamide gels coated with gelatin, the expressions of Nanog and Oct3/4 genes were higher than in cells cultured on rigid plastic dishes (∼10(6) kPa). The same result was obtained at higher elasticity (0.5 kPa) for adult human dermal fibroblasts (HDFa). We also examined whether reprogramming could be enhanced on soft substrates without exogenous gene introduction, finding that cells cultured on soft substrates in the presence of chemicals known to promote cell reprogramming exhibited up-regulated stem cell markers. These results suggest that controlling the substrate stiffness can enhance the initiation of cell reprogramming, which may lead to effective and reproducible iPS cell production.
authors.affiliation: RIKEN, Quantitative Biology Center (QBiC), 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan.
authors.forename: Sayaka
authors.initials: S
authors.lastname: Higuchi
authors.affiliation: RIKEN, Quantitative Biology Center (QBiC), 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan; WPI, Immunology Frontier Research Center, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan.
authors.forename: Tomonobu M
authors.initials: TM
authors.lastname: Watanabe
authors.affiliation: Mechanobiology Institute, National University of Singapore, 5A Engineering Drive 1, Singapore 117411, Singapore.
authors.forename: Keiko
authors.initials: K
authors.lastname: Kawauchi
authors.affiliation: RIKEN, Quantitative Biology Center (QBiC), 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan.
authors.forename: Taro
authors.initials: T
authors.lastname: Ichimura
authors.affiliation: RIKEN, Quantitative Biology Center (QBiC), 6-2-3 Furuedai, Suita, Osaka 565-0874, Japan; WPI, Immunology Frontier Research Center, Osaka University, 1-3 Yamadaoka, Suita, Osaka 565-0871, Japan. Electronic address: hideaki.fujita@riken.jp.
authors.forename: Hideaki
authors.initials: H
authors.lastname: Fujita
mesh_terms: D000178:Acrylamides / Q000737:chemistry; D053687:Adult Stem Cells / Q000378:metabolism; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000235:genetics; D002478:Cells, Cultured; D003470:Culture Media / Q000737:chemistry; D005347:Fibroblasts / Q000502:physiology; D015870:Gene Expression; D006244:Hardness; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D057026:Induced Pluripotent Stem Cells / Q000378:metabolism*; D000090062:Kruppel-Like Factor 4; D051379:Mice; D000071317:Nanog Homeobox Protein; D050814:Octamer Transcription Factor-3 / Q000235:genetics / Q000378:metabolism; D055748:SOXB1 Transcription Factors / Q000235:genetics / Q000378:metabolism; D014157:Transcription Factors / Q000235:genetics / Q000378:metabolism; D054460:rho-Associated Kinases / Q000378:metabolism
chemical_list: D000178:Acrylamides; D015415:Biomarkers; D003470:Culture Media; D018398:Homeodomain Proteins; C000715467:KLF4 protein, human; C000715468:Klf4 protein, mouse; D000090062:Kruppel-Like Factor 4; D000071317:Nanog Homeobox Protein; C475540:Nanog protein, mouse; D050814:Octamer Transcription Factor-3; C494174:Pou5f1 protein, mouse; C513672:Zfp42 protein, mouse; D055748:SOXB1 Transcription Factors; C527783:Sox2 protein, mouse; D014157:Transcription Factors; C515855:Rock2 protein, mouse; D054460:rho-Associated Kinases
keywords: Actin filament; Elasticity; Fibroblasts; Induced pluripotent stem cells; Reprogramming