title: Mechanical remodeling of normally sized mammalian cells under a gravity vector.
abstract: Translocation of the dense nucleus along a gravity vector initiates mechanical remodeling of a cell, but the underlying mechanisms of cytoskeletal network and focal adhesion complex (FAC) reorganization in a mammalian cell remain unclear. We quantified the remodeling of an MC3T3-E1 cell placed in upward-, downward-, or edge-on-orientated substrate. Nucleus longitudinal translocation presents a high value in downward orientation at 24 h or in edge-on orientation at 72 h, which is consistent with orientation-dependent distribution of perinuclear actin stress fibers and vimentin cords. Redistribution of total FAC area and fractionized super mature adhesion number coordinates this dependence at short duration. This orientation-dependent remodeling is associated with nucleus flattering and lamin A/C phosphorylation. Actin depolymerization or Rho-associated protein kinase signaling inhibition abolishes the orientation dependence of nucleus translocation, whereas tubulin polymerization inhibition or vimentin disruption reserves the dependence. A biomechanical model is therefore proposed for integrating the mechanosensing of nucleus translocation with cytoskeletal remodeling and FAC reorganization induced by a gravity vector.-Zhang, C., Zhou, L., Zhang, F., Lü, D., Li, N., Zheng, L., Xu, Y., Li, Z., Sun, S., Long, M. Mechanical remodeling of normally sized mammalian cells under a gravity vector.
authors.affiliation: Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Chen
authors.initials: C
authors.lastname: Zhang
authors.affiliation: Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Lüwen
authors.initials: L
authors.lastname: Zhou
authors.affiliation: Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Fan
authors.initials: F
authors.lastname: Zhang
authors.affiliation: Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Dongyuan
authors.initials: D
authors.lastname: Lü
authors.affiliation: Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Ning
authors.initials: N
authors.lastname: Li
authors.affiliation: Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Lu
authors.initials: L
authors.lastname: Zheng
authors.affiliation: Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Yanhong
authors.initials: Y
authors.lastname: Xu
authors.affiliation: Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Zhan
authors.initials: Z
authors.lastname: Li
authors.affiliation: Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China.
authors.forename: Shujin
authors.initials: S
authors.lastname: Sun
authors.affiliation: Center for Biomechanics and Bioengineering, Key Laboratory of Microgravity (National Microgravity Laboratory), and Beijing Key Laboratory of Engineered Construction and Mechanobiology, Institute of Mechanics, Chinese Academy of Sciences, Beijing, China mlong@imech.ac.cn.
authors.forename: Mian
authors.initials: M
authors.lastname: Long
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D018929:Cell Culture Techniques; D002460:Cell Line; D002467:Cell Nucleus; D015971:Gene Expression Regulation, Enzymologic; D006112:Gravitation; D051379:Mice; D010006:Osteoblasts / Q000166:cytology / Q000502:physiology*; D054460:rho-Associated Kinases / Q000235:genetics / Q000378:metabolism
chemical_list: D054460:rho-Associated Kinases
keywords: FAC reorganization; cytoskeletal remodeling; gravity-directed; mechanosensing; nucleus translocation