title: Transcriptional regulation of Hb-α and Hb-β through nuclear factor E2-related factor-2 (Nrf2) activation in human vaginal cells: A novel mechanism of cellular adaptability to oxidative stress.
abstract: Hemoglobin (Hb), a major protein involved in transport of oxygen (O2), is expressed by erythroid lineages. Until recently, it was not known whether non-erythroid cells express Hb. The objective was to evaluate the expression and functional significance of Hb-α and Hb-β in human primary vaginal epithelial cells (hPVECs) and decipher downstream signaling.
  
  
  
  RT-PCR, qRT-PCR, flow cytometry, Western blot, immunofluorescence were used to evaluate the expression of Hb-α, Hb-β, and nuclear factor E2-related factor-2(Nrf2) after hydrogen peroxide (H2O2) induction. Electrophoretic mobility shift assay (EMSA) and chromatin immunoprecipitation (ChIP) assay were used to determine the binding efficiency of Nrf2 on the Hb-α promoter.
  
  
  
  Stimulation of hPVECs and human vaginal epithelial cell line, VK2/E6E7 with H2O2augmented the expression of Hb-α, Hb-β, Nrf2, heme oxygenase-1 (HO-1), and reactive oxygen species (ROS). Treatment of these cells with Nrf2 inhibitor, trigonelline (Trig) inhibited Hb-α and Hb-β expressions. Hb-α and Hb-β overexpression downregulated H2O2-induced ROS. The presence of Nrf2 binding domain was demonstrated within Hb-α promoter.
  
  
  
  The results revealed for the first time that Hb-α and Hb-β were induced by oxidative stress through the activation of Nrf2. Overexpression of Hb-α and Hb-β ameliorated H2O2-induced oxidative stress, indicating one of the possible mechanism(s) to protect hPVECS from oxidative stress.
authors.affiliation: Division of Molecular Immunology and Microbiology (MIM), National Institute for Research in Reproductive Health (NIRRH), Mumbai, India.
authors.forename: Debarchana
authors.initials: D
authors.lastname: Saha
authors.affiliation: Division of Molecular Immunology and Microbiology (MIM), National Institute for Research in Reproductive Health (NIRRH), Mumbai, India.
authors.forename: Swanand
authors.initials: S
authors.lastname: Koli
authors.affiliation: Division of Molecular Immunology and Microbiology (MIM), National Institute for Research in Reproductive Health (NIRRH), Mumbai, India.
authors.forename: Kudumula Venkata Rami
authors.identifier: 0000-0003-0735-7662
authors.initials: KVR
authors.lastname: Reddy
mesh_terms: D000470:Alkaloids / Q000494:pharmacology; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004847:Epithelial Cells / Q000187:drug effects / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation; D051547:Heme Oxygenase-1 / Q000235:genetics; D006454:Hemoglobins / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D006861:Hydrogen Peroxide / Q000494:pharmacology; D051267:NF-E2-Related Factor 2 / Q000235:genetics*; D018384:Oxidative Stress / Q000187:drug effects; D012333:RNA, Messenger / Q000378:metabolism; D017382:Reactive Oxygen Species / Q000378:metabolism; D014621:Vagina / Q000166:cytology / Q000378:metabolism*
chemical_list: D000470:Alkaloids; D006454:Hemoglobins; D051267:NF-E2-Related Factor 2; D012333:RNA, Messenger; D017382:Reactive Oxygen Species; C009560:trigonelline; D006861:Hydrogen Peroxide; C496541:HMOX1 protein, human; D051547:Heme Oxygenase-1
keywords: H2O2; Hb-α; Hb-β; VK2/E6E7 cell line; hPVECs; oxidative stress