Bach1 differentially regulates distinct Nrf2-dependent genes in human venous and coronary artery endothelial cells adapted to physiological oxygen levels

Free Radic Biol Med. 2016 Mar:92:152-162. doi: 10.1016/j.freeradbiomed.2015.12.013. Epub 2015 Dec 15.

Abstract

The effects of physiological oxygen tension on Nuclear Factor-E2-Related Factor 2 (Nrf2)-regulated redox signaling remain poorly understood. We report the first study of Nrf2-regulated signaling in human primary endothelial cells (EC) adapted long-term to physiological O2 (5%). Adaptation of EC to 5% O2 had minimal effects on cell ultrastructure, viability, basal redox status or HIF1-α expression. Affymetrix array profiling and subsequent qPCR/protein validation revealed that induction of select Nrf2 target genes, HO-1 and NQO1, was significantly attenuated in cells adapted to 5% O2, despite nuclear accumulation and DNA binding of Nrf2. Diminished HO-1 induction under 5% O2 was stimulus independent and reversible upon re-adaptation to air or silencing of the Nrf2 repressor Bach1, notably elevated under 5% O2. Induction of GSH-related genes xCT and GCLM were oxygen and Bach1-insensitive during long-term culture under 5% O2, providing the first evidence that genes related to GSH synthesis mediate protection afforded by Nrf2-Keap1 defense pathway in cells adapted to physiological O2 levels encountered in vivo.

Keywords: Bach1; Coronary artery; Endothelial cells; GCL; Glutathione; Glutathione reductase GR; HO-1; Mitochondria; NQO1; Normoxia; Nuclear Factor-E2-Related Factor 2, Nrf2; Physiological oxygen tension; Redox signaling; Sequestosome-1; Solute Carrier Family 7-anionic amino acid transporter light chain xCT; Thioredoxin reductase-1.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amino Acid Transport System y+ / metabolism
  • Antioxidants / metabolism
  • Basic-Leucine Zipper Transcription Factors / genetics*
  • Basic-Leucine Zipper Transcription Factors / metabolism
  • Coronary Vessels / metabolism*
  • DNA-Binding Proteins / genetics
  • DNA-Binding Proteins / metabolism
  • Endothelial Cells / metabolism
  • Fanconi Anemia Complementation Group Proteins / genetics*
  • Fanconi Anemia Complementation Group Proteins / metabolism
  • Glutamate-Cysteine Ligase / metabolism
  • Glutathione / metabolism
  • Heme Oxygenase-1 / genetics
  • Heme Oxygenase-1 / metabolism
  • Humans
  • Hypoxia-Inducible Factor 1, alpha Subunit / genetics
  • Hypoxia-Inducible Factor 1, alpha Subunit / metabolism
  • Kelch-Like ECH-Associated Protein 1 / genetics
  • Kelch-Like ECH-Associated Protein 1 / metabolism*
  • NAD(P)H Dehydrogenase (Quinone) / genetics
  • NAD(P)H Dehydrogenase (Quinone) / metabolism
  • NF-E2-Related Factor 2 / genetics*
  • NF-E2-Related Factor 2 / metabolism
  • Oxygen / metabolism*
  • Reactive Oxygen Species / metabolism
  • Veins / metabolism

Substances

  • Amino Acid Transport System y+
  • Antioxidants
  • BACH1 protein, human
  • Basic-Leucine Zipper Transcription Factors
  • DNA-Binding Proteins
  • Fanconi Anemia Complementation Group Proteins
  • HIF1A protein, human
  • Hypoxia-Inducible Factor 1, alpha Subunit
  • KEAP1 protein, human
  • Kelch-Like ECH-Associated Protein 1
  • NF-E2-Related Factor 2
  • NFE2L2 protein, human
  • Reactive Oxygen Species
  • SLC7A11 protein, human
  • Heme Oxygenase-1
  • NAD(P)H Dehydrogenase (Quinone)
  • NQO1 protein, human
  • GCLM protein, human
  • Glutamate-Cysteine Ligase
  • Glutathione
  • Oxygen