Glucocorticoid-mediated gene suppression of rat cytokine-induced neutrophil chemoattractant CINC/gro, a member of the interleukin-8 family, through impairment of NF-kappa B activation.
The glucocorticoid dexamethasone inhibited the production of the rat cytokine-induced neutrophil chemoattractant CINC/gro, a counterpart of human melanoma growth-stimulating activity that belongs to the interleukin-8 (IL-8) family, in the normal rat kidney epithelial cell line NRK-52E stimulated with interleukin-1 beta (IL-1 beta), lipopolysaccharide, or tumor necrosis factor alpha. The accumulation of CINC/gro mRNA induced by these activators was also decreased comparably by dexamethasone. A nuclear run-on assay revealed that dexamethasone decreased the IL-1 beta-induced transcription of the CINC/gro gene. The half-life of CINC/gro mRNA transcripts did not change significantly after exposure to dexamethasone, suggesting that this glucocorticoid acts mainly at the transcriptional level. Transfection with luciferase expression vectors containing 5'-deleted and mutated CINC/gro gene sequences demonstrated that the 5'-flanking region containing the NF-kappa B binding site is involved in the IL-1 beta- and dexamethasone-induced activation and repression of the CINC/gro gene expression, respectively. Furthermore, a tandem repeat of the NF-kappa B sequence in the CINC/gro gene conferred the inducibility by IL-1 beta and suppression of luciferase activity by dexamethasone. In an electrophoretic mobility shift assay, dexamethasone diminished the IL-1 beta-induced formation of NF-kappa B complexes, which consisted of p65 and p50. Western blotting revealed that dexamethasone inhibited the IL-1 beta-induced translocation of p65 from the cytoplasm into the nucleus, while the nuclear level of NF-kappa B p50 remained almost unchanged. In addition, the degradation of I kappa B-alpha induced by IL-1 beta was not inhibited by dexamethasone. These results indicated that the suppression of the CINC/gro gene transcription by glucocorticoid occurs through the impairment of NF-kappa B activation, possibly by interference with the translocation of NF-kappa B p65 from the cytoplasm into the nucleus, thereby suppressing transactivation of the CINC/gro gene.
Ohtsuka
T
T
Institute of Cytosignal Research, Inc., Tokyo, Japan.
Kubota
A
A
Hirano
T
T
Watanabe
K
K
Yoshida
H
H
Tsurufuji
M
M
Iizuka
Y
Y
Konishi
K
K
Tsurufuji
S
S
D000818:Animals; D001483:Base Sequence; D015152:Blotting, Northern; D002455:Cell Division / Q000187:drug effects; D002460:Cell Line; D002467:Cell Nucleus / Q000378:metabolism; D054360:Chemokine CXCL1; D019743:Chemokines, CXC; D002630:Chemotactic Factors / Q000096:biosynthesis* / Q000494:pharmacology; D016207:Cytokines / Q000494:pharmacology*; D003907:Dexamethasone / Q000494:pharmacology*; D015870:Gene Expression / Q000187:drug effects*; D006131:Growth Inhibitors / Q000096:biosynthesis* / Q000494:pharmacology; D006133:Growth Substances / Q000096:biosynthesis* / Q000494:pharmacology; D006801:Humans; D036341:Intercellular Signaling Peptides and Proteins; D007375:Interleukin-1 / Q000494:pharmacology; D016209:Interleukin-8 / Q000096:biosynthesis / Q000494:pharmacology; D007668:Kidney; D007700:Kinetics; D008156:Luciferases / Q000096:biosynthesis; D008545:Melanoma / Q000473:pathology; D008969:Molecular Sequence Data; D016328:NF-kappa B / Q000187:drug effects / Q000378:metabolism*; D015345:Oligonucleotide Probes; D012333:RNA, Messenger / Q000032:analysis / Q000096:biosynthesis; D051381:Rats; D011993:Recombinant Fusion Proteins / Q000096:biosynthesis; D011994:Recombinant Proteins / Q000494:pharmacology; D013489:Suppression, Genetic / Q000187:drug effects*; D014158:Transcription, Genetic / Q000187:drug effects; D014162:Transfection; D014409:Tumor Necrosis Factor-alpha / Q000494:pharmacology
C475829:CXCL1 protein, human; D054360:Chemokine CXCL1; D019743:Chemokines, CXC; D002630:Chemotactic Factors; C513297:Cxcl1 protein, rat; D016207:Cytokines; D006131:Growth Inhibitors; D006133:Growth Substances; D036341:Intercellular Signaling Peptides and Proteins; D007375:Interleukin-1; D016209:Interleukin-8; D016328:NF-kappa B; D015345:Oligonucleotide Probes; D012333:RNA, Messenger; D011993:Recombinant Fusion Proteins; D011994:Recombinant Proteins; D014409:Tumor Necrosis Factor-alpha; D003907:Dexamethasone; D008156:Luciferases