title: 3D culture increases pluripotent gene expression in mesenchymal stem cells through relaxation of cytoskeleton tension.
abstract: Three-dimensional (3D) culture has been shown to improve pluripotent gene expression in mesenchymal stem cells (MSCs), but the underlining mechanisms were poorly understood. Here, we found that the relaxation of cytoskeleton tension of MSCs in 3D culture was critically associated with the expressional up-regulation of Nanog. Cultured in spheroids, MSCs showed decreased integrin-based cell-matrix adhesion but increased cadherin-based cell-cell interaction. Different from that in 2D culture, where MSCs exhibited branched and multiple-directed F-actin stress bundles at the cell edge and strengthened stress fibres transversing the cell body, MSCs cultured in spheroids showed compact cell body, relaxed cytoskeleton tension with very thin cortical actin filament outlining the cell, and increased expression of Nanog along with reduced levels of Suv39h1 (H3K9 methyltransferase) and H3K9me3. Notably, pharmaceutical inhibition of actin polymerization with cytochalasin D or silencing Suv39h1 expression with siRNA in 2D-cultured MSCs elevated the expression of Nanog via H3K9 demethylation. Thus, our data suggest that 3D culture increases the expression of Nanog through the relaxation of actin cytoskeleton, which mediates reduced Suv39h1 and H3K9me3 levels.
authors.affiliation: School of Life Sciences, Tsinghua University, Beijing, China.|The Shenzhen Key Laboratory of Health Sciences and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Zhou
authors.affiliation: The Shenzhen Key Laboratory of Health Sciences and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China.|Tsinghua-Berkeley Shenzhen Institute (TBSI), Tsinghua University, Beijing, China.
authors.forename: Haiyan
authors.initials: H
authors.lastname: Chen
authors.affiliation: Department of General Surgery, Qingdao Municipal Hospital Qingdao, Qingdao, China.
authors.forename: Hong
authors.initials: H
authors.lastname: Li
authors.affiliation: The Shenzhen Key Laboratory of Health Sciences and Technology, Graduate School at Shenzhen, Tsinghua University, Shenzhen, China.|Tsinghua-Berkeley Shenzhen Institute (TBSI), Tsinghua University, Beijing, China.
authors.forename: Yaojiong
authors.initials: Y
authors.lastname: Wu
mesh_terms: D008841:Actin Cytoskeleton / Q000235:genetics; D002450:Cell Communication / Q000235:genetics; D018929:Cell Culture Techniques; D002454:Cell Differentiation / Q000235:genetics*; D049109:Cell Proliferation / Q000235:genetics; D021982:Cell-Matrix Junctions / Q000235:genetics / Q000378:metabolism; D018507:Gene Expression Regulation, Developmental / Q000235:genetics; D011495:Histone-Lysine N-Methyltransferase / Q000235:genetics; D006801:Humans; D059630:Mesenchymal Stem Cells; D008780:Methyltransferases / Q000235:genetics; D000071317:Nanog Homeobox Protein / Q000235:genetics*; D012097:Repressor Proteins / Q000235:genetics
chemical_list: D000071317:Nanog Homeobox Protein; D012097:Repressor Proteins; C407843:SUV39H1 protein, human; D008780:Methyltransferases; D011495:Histone-Lysine N-Methyltransferase
keywords: 3D; Nanog; actin cytoskeleton; mesenchymal stem cell