Cadmium induces interleukin-8 production via NF-kappaB activation in the human intestinal epithelial cell, Caco-2.
In the present study, we investigated the effect of CdCl2 on the inflammatory cytokines in human intestinal Caco-2 cells. The secretion of IL-8 from Caco-2 cells was significantly increased in a dose- and time-dependent manner, whereas the secretion of such other inflammatory cytokines as TNF-alpha and IFN-gamma was not changed. And IL-8 mRNA level was significantly increased by exposing the cells to CdCl2. A reporter vector containing the IL-8 promoter region was then constructed to determine the IL-8 transcriptional activity. The results of this assay demonstrated that the transcriptional activity of IL-8 was increased by CdCl2. Treatment with PDTC, an NF-kappaB inhibitor, suppressed the IL-8 secretion in Caco-2 cells. Site-directed mutation of the NF-kappaB consensus element in the human IL-8 promoter abolished the increased transcriptional activity by CdCl2. The increased transcriptional activity caused by CdCl2 was also suppressed in an NF-kappaB knock-down Caco-2 cell line that had been stably established by the RNAi method. The increase in translocation of the NF-kappaB protein into the nucleus and I-kappaB alpha degradation resulting from CdCl2 stimulation was also confirmed by a Western analysis. Our results suggest that CdCl2 induced IL-8 secretion, its transcription, and its transcriptional activation regulated by NF-kappaB via I-kappaB alpha degradation.
Hyun
Ja Shil
JS
Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Science, The University of Tokyo, 1-1-1 Yayoi, Bunkyo-ku, Tokyo, Japan. minorihyun@yahoo.co.jp
Satsu
Hideo
H
Shimizu
Makoto
M
D018938:Caco-2 Cells; D019256:Cadmium Chloride / Q000494:pharmacology*; D004847:Epithelial Cells / Q000187:drug effects* / Q000378:metabolism*; D005786:Gene Expression Regulation; D006801:Humans; D051550:I-kappa B Kinase / Q000378:metabolism; D016209:Interleukin-8 / Q000096:biosynthesis* / Q000235:genetics / Q000378:metabolism; D007413:Intestinal Mucosa / Q000378:metabolism*; D007422:Intestines / Q000187:drug effects*; D016328:NF-kappa B / Q000378:metabolism*; D011401:Promoter Regions, Genetic / Q000235:genetics; D012333:RNA, Messenger / Q000235:genetics; D013997:Time Factors; D014158:Transcription, Genetic / Q000235:genetics
D016209:Interleukin-8; D016328:NF-kappa B; D012333:RNA, Messenger; D051550:I-kappa B Kinase; D019256:Cadmium Chloride