NcoA2-dependent inhibition of HIF-1α activation is regulated via AhR

Chi Hao Tsai, Ching Hao Li, Po Lin Liao, Yu Wen Cheng, Cheng Hui Lin, Shih Hsuan Huang, Jaw Jou Kang

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

High endogenous levels of aryl hydrocarbon receptor (AhR) contribute to hypoxia signaling pathway inhibition following exposure to the potent AhR ligand benzo[a]pyrene (B[a]P) and could alter cellular homeostasis and disease condition. Increasing evidence indicates that AhR might compete with AhR nuclear translocator (ARNT) for complex formation with hypoxia-inducible factor-1α (HIF-1α) for transactivation, which could alter several physiological variables. Nuclear receptor coactivator 2 (NcoA2) is a transcription coactivator that regulates transcription factor activation and inhibition of basic helix-loop-helix Per (Period)-ARNT-SIM (single-minded) (bHLH-PAS) family proteins, such as HIF-1α, ARNT, and AhR, through protein-protein interactions. In this study, we demonstrated that both hypoxia and hypoxia-mimic conditions decreased NcoA2 protein expression in HEK293T cells. Hypoxia response element (HRE) and xenobiotic-responsive element (XRE) transactivation also were downregulated with NcoA2 knockdown under hypoxic conditions. In addition, B[a]P significantly decreased NcoA2 protein expression be accompanied with AhR degradation. We next evaluated whether the absence of AhR could affect NcoA2 protein function under hypoxia-mimetic conditions. NcoA2 and HIF-1α nuclear localization decreased in both B[a]P-pretreated and AhR-knockdown HepG2 cells under hypoxia-mimic conditions. Interestingly, NcoA2 overexpression downregulated HRE transactivation by competing with HIF-1α and AhR to form protein complexes with ARNT. Both NcoA2 knockdown and overexpression inhibited endothelial cell tube formation in vitro. We also demonstrated using the in vivo plug assay that NcoA2-regulated vascularization decreased in mice. Taken together, these results revealed a biphasic role of NcoA2 between AhR and hypoxic conditions, thus providing a novel mechanism underlying the cross talk between AhR and hypoxia that affects disease development and progression.

Original languageEnglish
Article numberkfv199
Pages (from-to)517-530
Number of pages14
JournalToxicological Sciences
Volume148
Issue number2
DOIs
Publication statusPublished - Dec 1 2015

Fingerprint

Nuclear Receptor Coactivator 2
Hypoxia-Inducible Factor 1
Aryl Hydrocarbon Receptors
Chemical activation
Aryl Hydrocarbon Receptor Nuclear Translocator
Transcriptional Activation
Benzo(a)pyrene
Proteins
Response Elements
Down-Regulation
Cell Hypoxia
Endothelial cells
Hep G2 Cells
Xenobiotics
Transcription
Hypoxia
Disease Progression

Keywords

  • Aryl hydrocarbon receptor (AhR)
  • Benzo[a]pyrene (B[a]P)
  • Hypoxia-inducible factor-1α (HIF-1α)
  • Hypoxia-responsive element (HRE)
  • Nuclear receptor coactivator 2 (NcoA2)

ASJC Scopus subject areas

  • Toxicology

Cite this

Tsai, C. H., Li, C. H., Liao, P. L., Cheng, Y. W., Lin, C. H., Huang, S. H., & Kang, J. J. (2015). NcoA2-dependent inhibition of HIF-1α activation is regulated via AhR. Toxicological Sciences, 148(2), 517-530. [kfv199]. https://doi.org/10.1093/toxsci/kfv199

NcoA2-dependent inhibition of HIF-1α activation is regulated via AhR. / Tsai, Chi Hao; Li, Ching Hao; Liao, Po Lin; Cheng, Yu Wen; Lin, Cheng Hui; Huang, Shih Hsuan; Kang, Jaw Jou.

In: Toxicological Sciences, Vol. 148, No. 2, kfv199, 01.12.2015, p. 517-530.

Research output: Contribution to journalArticle

Tsai, CH, Li, CH, Liao, PL, Cheng, YW, Lin, CH, Huang, SH & Kang, JJ 2015, 'NcoA2-dependent inhibition of HIF-1α activation is regulated via AhR', Toxicological Sciences, vol. 148, no. 2, kfv199, pp. 517-530. https://doi.org/10.1093/toxsci/kfv199
Tsai, Chi Hao ; Li, Ching Hao ; Liao, Po Lin ; Cheng, Yu Wen ; Lin, Cheng Hui ; Huang, Shih Hsuan ; Kang, Jaw Jou. / NcoA2-dependent inhibition of HIF-1α activation is regulated via AhR. In: Toxicological Sciences. 2015 ; Vol. 148, No. 2. pp. 517-530.
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