Functional Diversity Between Rho-kinase- And MLCK-mediated Cytoskeletal Actions in a Myofibroblast-Like Hepatic Stellate Cell Line

Biochem Biophys Res Commun. 2003 May 30;305(2):223-8. doi: 10.1016/s0006-291x(03)00726-5.

Abstract

Using a rat myofibroblast-like hepatic stellate cell line, we studied the actomyosin-based cytoskeletal actions mediated by Rho-kinase and/or myosin light chain kinase (MLCK). Calmodulin/MLCK inhibitors W-7 and ML-7 attenuated cell migration dose-relatedly at concentrations from 10(-6) to 10(-4)M and collagen gel-contraction by the cells at 10(-4)M, respectively. Rho-kinase inhibitors Y-27632 and HA1077 attenuated the gel-contraction at concentrations from 10(-6) to 10(-4) M, respectively. These Rho-kinase inhibitors attenuated cell migration at 10(-7)M but enhanced the migration at 10(-4)M, respectively. They altered cell morphology showing prominent peripheral actin bundles and sparse central stress fibers, in comparison with the calmodulin/MLCK inhibitors. Both ML-7 and Y-27632 attenuated phosphorylation of myosin regulatory light chain and cell attachment to extracellular substrate. ML-7 attenuated the activation of GTP-binding protein Rac, while Y-27632 did not. These findings suggest that the actomyosin-based cytoskeletal actions can be functionally diverse depending on the Rho-kinase-mediated pathway and the MLCK-mediated pathway.

MeSH terms

  • Animals
  • Azepines / pharmacology
  • Calmodulin / antagonists & inhibitors
  • Cell Adhesion / drug effects
  • Cell Line
  • Cell Movement / drug effects
  • Collagen
  • Cytoskeleton / physiology*
  • Cytoskeleton / ultrastructure
  • Enzyme Inhibitors / pharmacology
  • Fibroblasts / enzymology*
  • Fibroblasts / physiology*
  • Fibroblasts / ultrastructure
  • Intracellular Signaling Peptides and Proteins
  • Liver / cytology*
  • Liver / enzymology
  • Muscle Cells / cytology
  • Myosin Light Chains / metabolism
  • Myosin-Light-Chain Kinase / antagonists & inhibitors
  • Myosin-Light-Chain Kinase / physiology*
  • Naphthalenes / pharmacology
  • Phosphorylation / drug effects
  • Protein-Serine-Threonine Kinases / antagonists & inhibitors
  • Protein-Serine-Threonine Kinases / physiology*
  • Rats
  • Sulfonamides / pharmacology
  • rac GTP-Binding Proteins / metabolism
  • rho-Associated Kinases

Substances

  • Azepines
  • Calmodulin
  • Enzyme Inhibitors
  • Intracellular Signaling Peptides and Proteins
  • Myosin Light Chains
  • Naphthalenes
  • Sulfonamides
  • ML 7
  • W 7
  • Collagen
  • Protein-Serine-Threonine Kinases
  • rho-Associated Kinases
  • Myosin-Light-Chain Kinase
  • rac GTP-Binding Proteins