Nuclear factor-kappa B activation pathway in intestinal epithelial cells is a major regulator of chemokine gene expression and neutrophil migration induced by Bacteroides fragilis enterotoxin.
Although intestinal epithelial cells are known to up-regulate the expression of several chemokine genes in response to the stimulation with B. fragilis enterotoxin (BFT), there has been little understanding on the cellular mechanisms of BFT-induced mucosal inflammation. To test whether nuclear transcriptional factor-kappa B (NF-kappaB) is involved in the process, we stimulated intestinal epithelial cells with BFT, and evaluated the signalling NF-kappaB pathways. BFT increased signals of NF-kappaB in HT-29 and T84 epithelial cell lines as well as primary human colon epithelial cells. NF-kappaB molecules activated by BFT stimulation were composed of p65 and p50 heterodimers. In contrast, BFT decreased the signals of IkappaBalpha and IkappaB epsilon, as assessed by immunoblot. Super-repressors of IkappaBalpha, IkappaB kinase (IKK)beta, and NF-kappaB inducing kinase (NIK) inhibited an up-regulated transcription of downstream target gene (CXCL8) of NF-kappaB. Moreover, blocking the activation of NF-kappaB by MG-132 or antisense p50 oligonucleotide transfection resulted in down-regulated expression of chemokines such as CXCL1, CXCL8, and CCL2 in BFT-stimulated HT-29 cells. In addition, NF-kappaB inhibition suppressed the BFT-induced neutrophil transepithelial migration in T84 cells. These results indicate that NF-kappaB can be a central regulator of chemokine gene expression in BFT-stimulated intestinal epithelial cells and may be an important regulator of neutrophil migration.
Kim
J M
JM
Department of Microbiology & Institute of Biomedical Science, Hanyang University College of Medicine, Seoul, Korea. jungmogg@hanyang.ac.kr
Cho
S J
SJ
Oh
Y-K
YK
Jung
H-Y
HY
Kim
Y-J
YJ
Kim
N
N
D000328:Adult; D001427:Bacterial Toxins / Q000494:pharmacology*; D001441:Bacteroides fragilis / Q000502:physiology*; D018925:Chemokines / Q000096:biosynthesis* / Q000235:genetics; D002634:Chemotaxis, Leukocyte / Q000187:drug effects*; D003106:Colon / Q000166:cytology; D003110:Colonic Neoplasms / Q000473:pathology; D004268:DNA-Binding Proteins / Q000378:metabolism; D024202:Electrophoretic Mobility Shift Assay; D004797:Enzyme-Linked Immunosorbent Assay; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects*; D017930:Genes, Reporter; D006801:Humans; D020672:I-kappa B Proteins; D016209:Interleukin-8 / Q000096:biosynthesis / Q000235:genetics; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000378:metabolism; D008156:Luciferases / Q000096:biosynthesis / Q000235:genetics; D008666:Metalloendopeptidases / Q000494:pharmacology*; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B / Q000502:physiology*; D009504:Neutrophils / Q000187:drug effects; D017346:Protein Serine-Threonine Kinases / Q000502:physiology; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D012097:Repressor Proteins / Q000502:physiology; D020133:Reverse Transcriptase Polymerase Chain Reaction; D014158:Transcription, Genetic / Q000187:drug effects*; D014407:Tumor Cells, Cultured / Q000187:drug effects / Q000378:metabolism; D000097782:NF-kappaB-Inducing Kinase
D001427:Bacterial Toxins; D018925:Chemokines; D004268:DNA-Binding Proteins; D020672:I-kappa B Proteins; D016209:Interleukin-8; D008156:Luciferases; D008666:Metalloendopeptidases; D000072000:NF-KappaB Inhibitor alpha; D016328:NF-kappa B; D017346:Protein Serine-Threonine Kinases; D011518:Proto-Oncogene Proteins; D012097:Repressor Proteins; D000097782:NF-kappaB-Inducing Kinase; C000606204:NFKBIA protein, human; C105627:NFKBIE protein, human; C405031:Bacteroides fragilis toxin