title: Cytoskeletal changes of mesenchymal stem cells during differentiation.
abstract: Mesenchymal stem cells (MSCs) are progenitors for tissues such as bone and cartilage. In this report, the actin cytoskeleton and nanomechanobiology of human mesenchymal stem cells (hMSCs) were studied using fluorescence microscopy and atomic force microscopy (AFM). Human MSCs were differentiated into chondrocytes and osteoblasts as per previous approaches. Cytochalasin D (CytD) was used to temporarily disrupt cytoskeleton in hMSCs, hMSC-chondrocytes (hMSC-Cys) and hMSC-osteoblasts (hMSC-Obs). Fluorescence microscopy revealed a dose-dependent response to CytD. Removal of CytD from the media of cytoskeleton-disrupted cells led to the recovery of the cytoskeletal structures, as confirmed by both fluorescence microscopy and AFM. Force-volume imaging by AFM evaluated the nanomechanics of all three cell types before, during, and after CytD treatment. Cytochalasin D disruption of cytoskeleton had marked effects on hMSCs and hMSC-Cys, in comparison with limited cytoskeleton disruption in hMSC-Obs, as confirmed qualitatively by fluorescence microscopy and quantitatively by AFM. Treatment with CytD resulted in morphology changes of all cell types, with significant decreases in the observed Young's Moduli of hMSCs and hMSC-Cys. These data suggest human mesenchymal stem cells alter their cytoskeletal components during differentiation. Additional studies will address the mechanisms of cytoskeletal changes using biochemical and biophysical methods.
authors.affiliation: Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, Illinois, USA.
authors.forename: Gregory
authors.initials: G
authors.lastname: Yourek
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Hussain
authors.forename: Jeremy J
authors.initials: JJ
authors.lastname: Mao
mesh_terms: D000199:Actins / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D001696:Biomechanical Phenomena; D002454:Cell Differentiation; D002470:Cell Survival / Q000187:drug effects; D002478:Cells, Cultured; D019902:Chondrocytes / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D015638:Cytochalasin D / Q000494:pharmacology; D003599:Cytoskeleton / Q000187:drug effects / Q000378:metabolism* / Q000648:ultrastructure; D004305:Dose-Response Relationship, Drug; D005456:Fluorescent Dyes; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D018625:Microscopy, Atomic Force; D008856:Microscopy, Fluorescence; D019384:Nucleic Acid Synthesis Inhibitors / Q000494:pharmacology; D010006:Osteoblasts / Q000187:drug effects / Q000502:physiology* / Q000648:ultrastructure; D010590:Phalloidine / Q000378:metabolism; D012235:Rhodamines; D013997:Time Factors
chemical_list: D000199:Actins; D005456:Fluorescent Dyes; D019384:Nucleic Acid Synthesis Inhibitors; D012235:Rhodamines; D010590:Phalloidine; D015638:Cytochalasin D; C009434:tetramethylrhodamine isothiocyanate