title: Cytoskeletal Configuration Modulates Mechanically Induced Changes in Mesenchymal Stem Cell Osteogenesis, Morphology, and Stiffness.
abstract: Mesenchymal stem cells (MSC) responding to mechanical cues generated by physical activity is critical for skeletal development and remodeling. Here, we utilized low intensity vibrations (LIV) as a physiologically relevant mechanical signal and hypothesized that the confined cytoskeletal configuration imposed by 2D culture will enable human bone marrow MSCs (hBMSC) to respond more robustly when LIV is applied in-plane (horizontal-LIV) rather than out-of-plane (vertical-LIV). All LIV signals enhanced hBMSC proliferation, osteogenic differentiation, and upregulated genes associated with cytoskeletal structure. The cellular response was more pronounced at higher frequencies (100 Hz vs 30 Hz) and when applied in the horizontal plane. Horizontal but not vertical LIV realigned the cell cytoskeleton, culminating in increased cell stiffness. Our results show that applying very small oscillatory motions within the primary cell attachment plane, rather than perpendicular to it, amplifies the cell's response to LIV, ostensibly facilitating a more effective transfer of intracellular forces. Transcriptional and structural changes in particular with horizontal LIV, together with the strong frequency dependency of the signal, emphasize the importance of intracellular cytoskeletal configuration in sensing and responding to high-frequency mechanical signals at low intensities.
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA.
authors.forename: Suphannee
authors.initials: S
authors.lastname: Pongkitwitoon
authors.affiliation: Department of Medicine, UNC Chapel Hill, Chapel Hill, NC 27517, USA.
authors.forename: Gunes
authors.initials: G
authors.lastname: Uzer
authors.affiliation: Department of Medicine, UNC Chapel Hill, Chapel Hill, NC 27517, USA.
authors.forename: Janet
authors.initials: J
authors.lastname: Rubin
authors.affiliation: Department of Biomedical Engineering, Stony Brook University, Stony Brook, NY 11794, USA.
authors.forename: Stefan
authors.initials: S
authors.lastname: Judex
mesh_terms: D000185:Actinin / Q000235:genetics; D000328:Adult; D015820:Cadherins / Q000235:genetics; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D049109:Cell Proliferation; D003599:Cytoskeleton / Q000502:physiology; D005260:Female; D005786:Gene Expression Regulation; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000737:chemistry / Q000502:physiology*; D008840:Microfilament Proteins / Q000235:genetics; D018625:Microscopy, Atomic Force; D009419:Nerve Tissue Proteins / Q000235:genetics; D009687:Nuclear Proteins / Q000235:genetics; D010012:Osteogenesis / Q000502:physiology*; D014732:Vibration
chemical_list: C526905:ACTN1 protein, human; D015820:Cadherins; D008840:Microfilament Proteins; D009419:Nerve Tissue Proteins; D009687:Nuclear Proteins; C485904:SYNE2 protein, human; D000185:Actinin; C086960:osteoblast cadherin