title: Geometric cues for directing the differentiation of mesenchymal stem cells.
abstract: Significant efforts have been directed to understanding the factors that influence the lineage commitment of stem cells. This paper demonstrates that cell shape, independent of soluble factors, has a strong influence on the differentiation of human mesenchymal stem cells (MSCs) from bone marrow. When exposed to competing soluble differentiation signals, cells cultured in rectangles with increasing aspect ratio and in shapes with pentagonal symmetry but with different subcellular curvature-and with each occupying the same area-display different adipogenesis and osteogenesis profiles. The results reveal that geometric features that increase actomyosin contractility promote osteogenesis and are consistent with in vivo characteristics of the microenvironment of the differentiated cells. Cytoskeletal-disrupting pharmacological agents modulate shape-based trends in lineage commitment verifying the critical role of focal adhesion and myosin-generated contractility during differentiation. Microarray analysis and pathway inhibition studies suggest that contractile cells promote osteogenesis by enhancing c-Jun N-terminal kinase (JNK) and extracellular related kinase (ERK1/2) activation in conjunction with elevated wingless-type (Wnt) signaling. Taken together, this work points to the role that geometric shape cues can play in orchestrating the mechanochemical signals and paracrine/autocrine factors that can direct MSCs to appropriate fates.
authors.affiliation: Department of Chemistry, and Howard Hughes Medical Institute, The University of Chicago, Chicago, IL 60637, USA.
authors.forename: Kristopher A
authors.initials: KA
authors.lastname: Kilian
authors.forename: Branimir
authors.initials: B
authors.lastname: Bugarija
authors.forename: Bruce T
authors.initials: BT
authors.lastname: Lahn
authors.forename: Milan
authors.initials: M
authors.lastname: Mrksich
mesh_terms: D017667:Adipocytes / Q000166:cytology; D002454:Cell Differentiation; D019070:Cell Lineage; D048430:Cell Shape; D016000:Cluster Analysis; D003599:Cytoskeleton / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D006801:Humans; D020935:MAP Kinase Signaling System; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000201:enzymology; D024507:Nonmuscle Myosin Type IIA / Q000378:metabolism; D010006:Osteoblasts / Q000166:cytology; D012313:RNA / Q000378:metabolism; D051153:Wnt Proteins / Q000378:metabolism
chemical_list: D051153:Wnt Proteins; D012313:RNA; D024507:Nonmuscle Myosin Type IIA