科研之友
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摘要
Purpose: The aim of this study was to investigate the signaling mechanisms surrounding changes in tight junction (IT and the permeability of human intestinal epithelial cell induced by tumor necrosis factor-alpha (TNF-alpha). Methods: To confirm that TNF-alpha induces epithelial barrier hyperpermeability by disrupting tight junction, Caco-2 cells were exposed to TNF-alpha, and changes in epithelial permeability (via TER assay), F-actin dynamics (via Rhodamine-phalloidin staining) and tight junction protein expression (via western blot) were monitored. Moreover, to ensure that NF-kappa B participated in the regulatory mechanisms, Caco-2 cells were transfected with DNMu-I kappa B alpha or control plasmids, the above experiments were repeated and the activation effect of TNF-alpha on NF-kappa B was detected by luciferase reporter assays. Lastly, we took dominant negative plasmid and knockdown approaches to investigate the potential importance of the NF-kappa B/myosin light chain kinase (MLCK)/myosin light chain phosphorylation (pMLC) pathways in TNF-a-mediated damage. Result: TNF-alpha could cause NF-kappa B activation, F-actin rearrangement, tight junction disruption and barrier dysfunction. These effects were alleviated by inhibiting NF-kappa B. TNF-alpha induced increase of MLCK transcription and MLC phosphorylation act later than NF-kappa B activation, which could be suppressed both by inactivating and deleting NF-kappa B. Conclusions: TNF-alpha induces intestinal epithelial cell hyperpermeability by disrupting Tjs, in part through MLCK upregulation, in which NF-kappa B is the positive upstream regulator for MLCK.
- 出版日期2012-8
- 单位中南大学
