Functional Interaction of HIF-1 and NF-kappaB Increasing the Transcriptional Activation of TNF-alpha Gene in Monocytes / 대한수혈학회지
Korean Journal of Blood Transfusion
; : 21-32, 2013.
Article
in En
| WPRIM
| ID: wpr-173039
Responsible library:
WPRO
ABSTRACT
BACKGROUND: Tumor necrosis factor alpha (TNF-alpha) is a pleiotropic cytokine fulfilling a broad variety of immunoregulatory functions. Monocytes and macrophages play a pivotal role in inflammation and immune regulation. NF-kappaB and HIF-1 are known to increase expression of the TNF-alpha gene in a separate way. METHODS: Human monocytic leukemia, U937 cells, were transfected using the standard electroporation method for intracellular expression of NF-kappaB and HIF-1. We performed analysis using the mammalian two-hybrid assay and co-immunoprecipitation assay for detection of protein interaction of both proteins. In addition, chromatin immunoprecipitation analysis was performed for examination of NF-kappaB and HIF-1 binding on the TNF-alpha gene promoter. RESULTS: Here we show that NF-kappaB and HIF-1 cooperatively induced an increase in expression of the TNF-alpha gene dependent on promoter activity by the direct protein interaction of these two transcription factors. Hypoxia signaling induced marked enhancement of the transactivation of TNF-alpha promoter by HIF-1 and NF-kappaB. A tandem NF-kappaB/HIF-1 binding site was identified within the TNF-alpha promoter, which acted as a strong enhancer element. Physical association of the Rel domain of NF-kappaB and the N-TD domain of HIF-1 was required. Hypoxia treatment also resulted in a significant increase in the protein interaction of NF-kappaB and HIF-1 in vivo. Both transcription factors were recruited on the chromatin TNF-alpha promoter dependent on hypoxia stimuli. CONCLUSION: The results of this study indicate that a variety of extracellular signals for activation of TNF-alpha gene expression might converge on the transcriptional regulation through the NF-kappaB/HIF-1 signaling pathway.
Key words
Full text:
1
Index:
WPRIM
Main subject:
Transcription Factors
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Binding Sites
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Chromatin
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Monocytes
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Leukemia
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Proteins
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Gene Expression
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Transcriptional Activation
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NF-kappa B
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Enhancer Elements, Genetic
Type of study:
Prognostic_studies
Limits:
Humans
Language:
En
Journal:
Korean Journal of Blood Transfusion
Year:
2013
Type:
Article