A Mechanism for the Up-regulation of the IL-8 Gene Expression in Keratinocytes by All-trans Retinoic Acid.
- Author:
Yae Lee CHUNG
1
;
Tae Won KANG
;
Sung Min OH
;
Seung Yong CHUNG
;
Soo Chan KIM
Author Information
1. Department of Dermatology and Cutaneous Biology Research Institute, Yonsei University College of Medicine, Seoul, Korea. kimsc@yuhs.ac
- Publication Type:Original Article
- Keywords:
HaCaT cells;
IL-8;
NF-kappaB;
Retinoic acid
- MeSH:
Binding Sites;
Blotting, Western;
Cytokines;
Dissociative Disorders;
Fibroblasts;
Gene Expression;
Interleukin-1;
Interleukin-8;
Keratinocytes;
NF-kappa B;
RNA, Messenger;
Tretinoin;
Tumor Necrosis Factor-alpha;
Up-Regulation
- From:Korean Journal of Dermatology
2009;47(6):674-682
- CountryRepublic of Korea
- Language:Korean
-
Abstract:
BACKGROUND: Retinoic acid (RA) has been reported to induce the up-regulation of inflammatory cytokines such as IL-1, TNF-alpha and IL-8 in dermal fibroblasts and keratinocytes. There is no evidence to support a direct interaction between the RA-mediated transcriptional machinery and IL-8 gene transcription. OBJECTIVE: The aim of this study is to clarify the mechanism of the up-regulation of IL-8 in keratinocytes by RA. METHODS: The IL-1, IL-8, TNF-alpha and MCP-1 mRNA expressions in HaCaT cells stimulated by RA were measured by quantitative RT-PCR. The effects of a NF-kappaB inhibitor and IL-1 receptor antagonist (ra) on the IL-8 mRNA expression were measured by quantitative RT-PCR. Electrophoretic motility shift assay (EMSA) was conducted on the RA-stimulated HaCaT cells that were or were not treated with NF-kappaB inhibitor to measure the NF-kappaB binding activity in each group. The phospho-IkappaB activity in the HaCaT cells after stimulation with RA was also measured by Western blotting. RESULTS: An up-regulation of the IL-8 gene expression by RA was demonstrated in the HaCaT cells. The inhibition assay revealed the involvement of the NF-kappaB binding site of the IL-8 gene in the RA-enhanced promoter activity. EMSA demonstrated that RA enhanced the formation of the DNA-NF-kappaB complex. There was no evidence to support IL-1 as an intermediate stimulus between the RA-mediated transcriptional machinery and IL-8 gene transcription. Western blot analysis revealed increased phospho-IkappaB activity in the HaCaT cells after stimulation with RA. CONCLUSION: Our result suggested that the IL-8 gene expression of HaCaT cells after RA stimulation is caused by the activation of IKK and the dissociation of IkappaB from NF-kappaB and the transcription of NF-kappaB in the nucleus.
