title: Uni-axial stretch induces actin stress fiber reorganization and activates c-Jun NH2 terminal kinase via RhoA and Rho kinase in human bladder smooth muscle cells.
abstract: BACKGROUND
  Excessive mechanical overload may be involved in bladder wall remodelling. Since the activity of Rho kinase is known to be upregulated in the obstructed bladder, we investigate the roles of the RhoA/Rho kinase pathway in mechanical overloaded bladder smooth muscle cells.
  
  
  METHODS
  Human bladder smooth muscle cells were stimulated on silicon culture plates by 15 % elongated uni-axial cyclic stretch at 1 Hz. The activity of c-Jun NH2-terminal kinase was measured by western blotting and actin stress fibers were observed by stained with phallotoxin conjugated with Alexa-Fluor 594.
  
  
  RESULTS
  The activity of c-Jun NH2-terminal kinase 1 peaked at 30 min (4.7-fold increase vs. before stretch) and this activity was partially abrogated by the RhoA inhibitor, C3 exoenzoyme or by the Rho kinase inhibitor, Y-27632. Stretch induced the strong formation of actin stress fibers and these fibers re-orientated in a direction that was perpendicular to the stretch direction. The average angle of the fibers from the perpendicular to the direction of stretch was significantly different between before, and 4 h after, stretch. Actin stress fibers reorganization was also suppressed by the C3 exoenzyme or Y-27632.
  
  
  CONCLUSIONS
  Bladder smooth muscle cells appear to have elaborate mechanisms for sensing mechanical stress and for adapting to mechanical stress overload by cytoskeletal remodeling and by activating cell growth signals such as c-Jun NH2-terminal kinase via RhoA/Rho kinase pathways.
authors.affiliation: Department of Urology, Fukushima Medical University School of Medicine, 1, Hikarigaoka, Fukushima, 960-1295, Japan. no7744@fmu.ac.jp.
authors.forename: Nobuhiro
authors.initials: N
authors.lastname: Kushida
authors.affiliation: Division of Bioengineering and LUTD Research, Nihon University School of Engineering, Nihon University, 1, Nakagawara, Tokusada, Tamura, Koriyama, 963-8642, Japan. yamaosa@ee.ce.nihon-u.ac.jp.
authors.forename: Osamu
authors.initials: O
authors.lastname: Yamaguchi
authors.affiliation: Department of Urology, Fukushima Medical University School of Medicine, 1, Hikarigaoka, Fukushima, 960-1295, Japan. yoheik@fmu.ac.jp.
authors.forename: Yohei
authors.initials: Y
authors.lastname: Kawashima
authors.affiliation: Department of Urology, Fukushima Medical University School of Medicine, 1, Hikarigaoka, Fukushima, 960-1295, Japan. hakai@fmu.ac.jp.
authors.forename: Hidenori
authors.initials: H
authors.lastname: Akaihata
authors.affiliation: Department of Urology, Fukushima Medical University School of Medicine, 1, Hikarigaoka, Fukushima, 960-1295, Japan. akju826@fmu.ac.jp.
authors.forename: Junya
authors.initials: J
authors.lastname: Hata
authors.affiliation: Department of Urology, Fukushima Medical University School of Medicine, 1, Hikarigaoka, Fukushima, 960-1295, Japan. keikun@fmu.ac.jp.
authors.forename: Kei
authors.initials: K
authors.lastname: Ishibashi
authors.affiliation: Department of Urology, Fukushima Medical University School of Medicine, 1, Hikarigaoka, Fukushima, 960-1295, Japan. kaika@fmu.ac.jp.
authors.forename: Ken
authors.initials: K
authors.lastname: Aikawa
authors.affiliation: Department of Urology, Fukushima Medical University School of Medicine, 1, Hikarigaoka, Fukushima, 960-1295, Japan. ykojima@fmu.ac.jp.
authors.forename: Yoshiyuki
authors.initials: Y
authors.lastname: Kojima
mesh_terms: D036002:ADP Ribose Transferases / Q000494:pharmacology; D000199:Actins / Q000187:drug effects / Q000378:metabolism*; D000577:Amides / Q000494:pharmacology; D015153:Blotting, Western; D001905:Botulinum Toxins / Q000494:pharmacology; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006801:Humans; D048055:Mitogen-Activated Protein Kinase 8 / Q000378:metabolism*; D032389:Myocytes, Smooth Muscle / Q000187:drug effects / Q000378:metabolism* / Q000502:physiology; D011725:Pyridines / Q000494:pharmacology; D015398:Signal Transduction / Q000502:physiology; D022502:Stress Fibers / Q000187:drug effects / Q000378:metabolism*; D013314:Stress, Mechanical; D001743:Urinary Bladder / Q000166:cytology*; D054460:rho-Associated Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D020742:rhoA GTP-Binding Protein / Q000037:antagonists & inhibitors / Q000378:metabolism*
chemical_list: D000199:Actins; D000577:Amides; D004791:Enzyme Inhibitors; D011725:Pyridines; C066737:RHOA protein, human; C108830:Y 27632; D036002:ADP Ribose Transferases; C063007:exoenzyme C3, Clostridium botulinum; D054460:rho-Associated Kinases; D048055:Mitogen-Activated Protein Kinase 8; D001905:Botulinum Toxins; D020742:rhoA GTP-Binding Protein