Calcium-dependent interleukin-8 gene expression in T84 human colonic epithelial cells.
OBJECTIVE
IL-8 is a chemokine that activates and recruits neutrophils and plays a major role in intestinal inflammation. Signal transduction pathways mediated by protein kinases are central in regulating IL-8 gene expression, however, little is known about the role of Ca2+ in this event. In this study, we characterize the effect of intracellular Ca2+ on interleukin-8 gene expression in T84 human colonic epithelial cells.


METHODS
Cells were stimulated with Ca2+ ionophore, A23187 or thapsigargin, a Ca2+-ATPase inhibitor. Semi-quantitative RT-PCR was used to examine IL-8 mRNA and ELISA for protein quantification. Reporter gene techniques were used to determine transcription rate.


RESULTS
A23187 and thapsigargin caused a dose- and time-dependent accumulation of IL-8 mRNA and protein production which was dependent on the release of Ca2+ from intracellular stores. FK506, a specific inhibitor of calcineurin, inhibited A23187- and thapsigargin-induced IL-8 mRNA expression in a dose dependent manner. Reporter gene studies and actinomycin D chase experiments showed that A23187 and thapsigargin enhanced IL-8 gene transcription and stabilized IL-8 mRNA transcripts, respectively.


CONCLUSIONS
Intracellular Ca2+ plays an important role in regulating IL-8 transcriptionally and posttranscriptionally through calcium/calmodulin-dependent calcineurin.
Yu
Y
Y
Institute of Parasitology of McGill University, Ste. Anne de Bellevue, Quebec, Canada.
De Waele
C
C
Chadee
K
K
D000230:Adenocarcinoma; D000001:Calcimycin / Q000494:pharmacology; D019703:Calcineurin / Q000494:pharmacology; D002118:Calcium / Q000494:pharmacology*; D003106:Colon / Q000378:metabolism*; D003110:Colonic Neoplasms; D004305:Dose-Response Relationship, Drug; D004847:Epithelial Cells / Q000378:metabolism; D015870:Gene Expression / Q000187:drug effects; D006801:Humans; D016209:Interleukin-8 / Q000235:genetics*; D007476:Ionophores / Q000494:pharmacology; D007700:Kinetics; D011493:Protein Kinase C / Q000378:metabolism; D012333:RNA, Messenger / Q000032:analysis; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D019284:Thapsigargin / Q000494:pharmacology; D014158:Transcription, Genetic / Q000187:drug effects; D014407:Tumor Cells, Cultured
D016209:Interleukin-8; D007476:Ionophores; D012333:RNA, Messenger; D000001:Calcimycin; D019284:Thapsigargin; D011493:Protein Kinase C; D019703:Calcineurin; D013755:Tetradecanoylphorbol Acetate; D002118:Calcium