Cytochalasin B modulation of Caco-2 tight junction barrier: Role of myosin light chain kinase

Thomas Ma, Neil T. Hoa, Daniel D. Tran, Vuong Bui, Ali Pedram, Susan Mills, Margaret Merryfield

Research output: Contribution to journalArticlepeer-review

89 Scopus citations

Abstract

The intracellular mechanisms that mediate cytochalasin-induced increase in intestinal epithelial tight junction (TJ) permeability are unclear. In this study, we examined the involvement of myosin light chain kinase (MLCK) in this process, using the filter-grown Caco-2 intestinal epithelial monolayers. Cytochalasin B (Cyto B) (5 μg/ml) produced an increase in Caco-2 MLCK activity, which correlated with the increase in Caco-2 TJ permeability. The inhibition of Cyto B-induced MLCK activation prevented the increase in Caco-2 TJ permeability. Additionally, myosin-Mg2+-ATPase inhibitor and metabolic inhibitors (which inhibit MLCK induced actin-myosin contraction) also prevented the Cyto B-induced increase in Caco-2 TJ permeability. Cyto B caused a late-phase (15-30 min) aggregation of actin fragments into large actin clumps, which was also inhibited by MLCK inhibitors. Cyto B produced a morphological disturbance of the ZO-1 TJ proteins, visually correlating with the functional increase in Caco-2 TJ permeability. The MLCK and myosin-Mg2+-ATPase inhibitors prevented both the functional increase in TJ permeability and disruption of ZO-1 proteins. These findings suggested that Cyto B-induced increase in Caco-2 TJ permeability is regulated by MLCK activation.

Original languageEnglish (US)
Pages (from-to)G875-G885
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume279
Issue number5 42-5
DOIs
StatePublished - 2000

All Science Journal Classification (ASJC) codes

  • Physiology
  • Hepatology
  • Gastroenterology
  • Physiology (medical)

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