TY - JOUR
T1 - Lipopolysaccharide-Induced Increase in Intestinal Epithelial Tight Permeability Is Mediated by Toll-Like Receptor 4/Myeloid Differentiation Primary Response 88 (MyD88) Activation of Myosin Light Chain Kinase Expression
AU - Nighot, Meghali
AU - Al-Sadi, Rana
AU - Guo, Shuhong
AU - Rawat, Manmeet
AU - Nighot, Prashant
AU - Watterson, Martin D.
AU - Ma, Thomas Y.
N1 - Publisher Copyright:
© 2017
PY - 2017/12
Y1 - 2017/12
N2 - Lipopolysaccharides (LPSs) are a major component of the Gram-negative bacterial cell wall and play an important role in mediating intestinal inflammatory responses in inflammatory bowel disease. Although recent studies suggested that physiologically relevant concentrations of LPS (0 to 1 ng/mL) cause an increase in intestinal epithelial tight junction (TJ) permeability, the mechanisms that mediate an LPS-induced increase in intestinal TJ permeability remain unclear. Herein, we show that myosin light chain kinase (MLCK) plays a central role in the LPS-induced increase in TJ permeability. Filter-grown Caco-2 intestinal epithelial monolayers and C57BL/6 mice were used as an in vitro and in vivo intestinal epithelial model system, respectively. LPS caused a dose- and time-dependent increase in MLCK expression and kinase activity in Caco-2 monolayers. The pharmacologic MLCK inhibition and siRNA-induced knock-down of MLCK inhibited the LPS-induced increase in Caco-2 TJ permeability. The LPS increase in TJ permeability was mediated by toll-like receptor 4 (TLR-4)/MyD88 signal-transduction pathway up-regulation of MLCK expression. The LPS-induced increase in mouse intestinal permeability also required an increase in MLCK expression. The LPS-induced increase in intestinal permeability was inhibited in MLCK−/− and TLR-4−/− mice. These data show, for the first time, that the LPS-induced increase in intestinal permeability was mediated by TLR-4/MyD88 signal-transduction pathway up-regulation of MLCK. Therapeutic targeting of these pathways can prevent an LPS-induced increase in intestinal permeability.
AB - Lipopolysaccharides (LPSs) are a major component of the Gram-negative bacterial cell wall and play an important role in mediating intestinal inflammatory responses in inflammatory bowel disease. Although recent studies suggested that physiologically relevant concentrations of LPS (0 to 1 ng/mL) cause an increase in intestinal epithelial tight junction (TJ) permeability, the mechanisms that mediate an LPS-induced increase in intestinal TJ permeability remain unclear. Herein, we show that myosin light chain kinase (MLCK) plays a central role in the LPS-induced increase in TJ permeability. Filter-grown Caco-2 intestinal epithelial monolayers and C57BL/6 mice were used as an in vitro and in vivo intestinal epithelial model system, respectively. LPS caused a dose- and time-dependent increase in MLCK expression and kinase activity in Caco-2 monolayers. The pharmacologic MLCK inhibition and siRNA-induced knock-down of MLCK inhibited the LPS-induced increase in Caco-2 TJ permeability. The LPS increase in TJ permeability was mediated by toll-like receptor 4 (TLR-4)/MyD88 signal-transduction pathway up-regulation of MLCK expression. The LPS-induced increase in mouse intestinal permeability also required an increase in MLCK expression. The LPS-induced increase in intestinal permeability was inhibited in MLCK−/− and TLR-4−/− mice. These data show, for the first time, that the LPS-induced increase in intestinal permeability was mediated by TLR-4/MyD88 signal-transduction pathway up-regulation of MLCK. Therapeutic targeting of these pathways can prevent an LPS-induced increase in intestinal permeability.
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U2 - 10.1016/j.ajpath.2017.08.005
DO - 10.1016/j.ajpath.2017.08.005
M3 - Article
C2 - 29157665
AN - SCOPUS:85034224944
SN - 0002-9440
VL - 187
SP - 2698
EP - 2710
JO - American Journal of Pathology
JF - American Journal of Pathology
IS - 12
ER -