Cyclic stretch disrupts apical junctional complexes in Caco-2 cell monolayers by a JNK-2-, c-Src-, and MLCK-dependent mechanism.
The intestinal epithelium is subjected to various types of mechanical stress. In this study, we investigated the impact of cyclic stretch on tight junction and adherens junction integrity in Caco-2 cell monolayers. Stretch for 2 h resulted in a dramatic modulation of tight junction protein distribution from a linear organization into wavy structure. Continuation of cyclic stretch for 6 h led to redistribution of tight junction proteins from the intercellular junctions into the intracellular compartment. Disruption of tight junctions was associated with redistribution of adherens junction proteins, E-cadherin and β-catenin, and dissociation of the actin cytoskeleton at the actomyosin belt. Stretch activates JNK2, c-Src, and myosin light-chain kinase (MLCK). Inhibition of JNK, Src kinase or MLCK activity and knockdown of JNK2 or c-Src attenuated stretch-induced disruption of tight junctions, adherens junctions, and actin cytoskeleton. Paracellular permeability measured by a novel method demonstrated that cyclic stretch increases paracellular permeability by a JNK, Src kinase, and MLCK-dependent mechanism. Stretch increased tyrosine phosphorylation of occludin, ZO-1, E-cadherin, and β-catenin. Inhibition of JNK or Src kinase attenuated stretch-induced occludin phosphorylation. Immunofluorescence localization indicated that phospho-MLC colocalizes with the vesicle-like actin structure at the actomyosin belt in stretched cells. On the other hand, phospho-c-Src colocalizes with the actin at the apical region of cells. This study demonstrates that cyclic stretch disrupts tight junctions and adherens junctions by a JNK2, c-Src, and MLCK-dependent mechanism.
Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee.
Geetha
G
Samak
Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee.
Ruchika
R
Gangwar
Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee.
Lynn M
LM
Crosby
Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee.
Leena P
LP
Desai
Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee.
Kristina
K
Wilhelm
Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee.
Christopher M
CM
Waters
Department of Physiology, University of Tennessee Health Science Center, Memphis, Tennessee rrao2@uthsc.edu.
RadhaKrishna
R
Rao
D000199:Actins / Q000502:physiology; D022005:Adherens Junctions / Q000502:physiology; D000873:Anthracenes; D018938:Caco-2 Cells; D004789:Enzyme Activation / Q000502:physiology*; D016391:Genes, src / Q000502:physiology*; D006801:Humans; D019563:Mechanics; D048056:Mitogen-Activated Protein Kinase 9 / Q000378:metabolism*; D009219:Myosin-Light-Chain Kinase / Q000235:genetics / Q000378:metabolism*; D010507:Periodicity; D010766:Phosphorylation; D011743:Pyrimidines; D019108:Tight Junctions / Q000502:physiology*; D014443:Tyrosine / Q000031:analogs & derivatives
C412373:AG 1879; D000199:Actins; D000873:Anthracenes; D011743:Pyrimidines; C036387:tyrosinamide; C432165:pyrazolanthrone; D014443:Tyrosine; D048056:Mitogen-Activated Protein Kinase 9; D009219:Myosin-Light-Chain Kinase
actin cytoskeleton; adherens junction; epithelium; intestine; tight junction