title: Dynamic regulation of HIF1Α stability by SUMO2/3 and SENP3 in the human placenta.
abstract: BACKGROUND
  Hypoxia-inducible factor 1A (HIF1A) stability is tightly regulated by hydroxylation and ubiquitination. Emerging evidence indicates that HIF1A is also controlled by the interplay between SUMO-specific ligases, which execute protein SUMOylation, and Sentrin/SUMO-specific proteases that de-SUMOylate target proteins. Given the significance of HIF1A in the human placenta, we investigated whether placental HIF1A is subject to SUMOylation in physiological and pathological conditions.
  
  
  METHODS
  Placentae were obtained from normal and pregnancies complicated by preeclampsia. Human choriocarcinoma JEG3 cells were maintained at either 21% or 3% oxygen or exposed to sodium nitroprusside (SNP). Cells were transfected with SUMO2/3 constructs with and without Mg132, a proteasome inhibitor. Expression, distribution and associations of SUMO/SENPs and HIF1A were evaluated by Western blotting, immunohistochemistry and co-immunoprecipitation.
  
  
  RESULTS
  HIF1A-SUMO2/3 associations peaked at 9-10 weeks, while its deSUMOylation by SENP3 was greatest at 10-12 weeks. In E-PE, HIF1A deSUMOylation by SENP3 was significantly elevated, while HIF1A-SUMO2/3 associations remained constant. In vitro, overexpression of SUMO2/3 de-stabilized HIF1A in hypoxia, and abrogated HIF1A expression following Mg132 treatment in normoxia. Hypoxia and SNP treatments promoted SENP3 nuclear redistribution from nucleoli to the nucleoplasm where it associates with HIF1A.
  
  
  CONCLUSIONS
  During early placental development, SUMOylation events control HIF1A stability in an oxygen-dependent manner. In E-PE, enhanced deSUMOylation of HIF1A by SENP3 may in part contribute to increased HIF1A activity and stability found in this pathology.
authors.affiliation: Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada. Electronic address: jayontabhatta@gmail.com.
authors.forename: Jayonta
authors.initials: J
authors.lastname: Bhattacharjee
authors.affiliation: Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada; Department of Physiology, University of Toronto, Toronto, Ontario, Canada. Electronic address: alahari@lunenfeld.ca.
authors.forename: Sruthi
authors.initials: S
authors.lastname: Alahari
authors.affiliation: Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada; Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada. Electronic address: sallais@lunenfeld.ca.
authors.forename: Julien
authors.initials: J
authors.lastname: Sallais
authors.affiliation: Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada. Electronic address: tagliaferro@lunenfeld.ca.
authors.forename: Andrea
authors.initials: A
authors.lastname: Tagliaferro
authors.affiliation: Department of Physiology, University of Toronto, Toronto, Ontario, Canada; Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada; Department of Pediatrics, University of Toronto, Toronto, Ontario, Canada; The Hospital for Sick Children, Toronto, Ontario, Canada. Electronic address: martin.post@sickkids.ca.
authors.forename: Martin
authors.initials: M
authors.lastname: Post
authors.affiliation: Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada; Department of Obstetrics and Gynecology, University of Toronto, Toronto, Ontario, Canada; Department of Physiology, University of Toronto, Toronto, Ontario, Canada; Institute of Medical Sciences, University of Toronto, Toronto, Ontario, Canada. Electronic address: caniggia@lunenfeld.ca.
authors.forename: Isabella
authors.initials: I
authors.lastname: Caniggia
mesh_terms: D016022:Case-Control Studies; D045744:Cell Line, Tumor; D003546:Cysteine Endopeptidases / Q000378:metabolism*; D005260:Female; D006801:Humans; D000860:Hypoxia / Q000378:metabolism; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism*; D010929:Placentation; D011225:Pre-Eclampsia / Q000378:metabolism*; D011247:Pregnancy; D025841:Small Ubiquitin-Related Modifier Proteins / Q000378:metabolism; D058207:Sumoylation; D014452:Ubiquitins / Q000378:metabolism
chemical_list: C497442:HIF1A protein, human; D051795:Hypoxia-Inducible Factor 1, alpha Subunit; C117909:SUMO2 protein, human; C492189:SUMO3 protein, human; D025841:Small Ubiquitin-Related Modifier Proteins; D014452:Ubiquitins; D003546:Cysteine Endopeptidases; C499718:SENP3 protein, human
keywords: Hypoxia-inducible factor; Oxygen; Placenta; Preeclampsia; SENP proteins; SUMO proteins