title: The redox function of APE1 is involved in the differentiation process of stem cells toward a neuronal cell fate.
abstract: Low-to-moderate levels of reactive oxygen species (ROS) govern different steps of neurogenesis via molecular pathways that have been decrypted only partially. Although it has been postulated that redox-sensitive molecules are involved in neuronal differentiation, the molecular bases for this process have not been elucidated yet. The aim of this work was therefore to study the role played by the redox-sensitive, multifunctional protein APE1/Ref-1 (APE1) in the differentiation process of human adipose tissue-derived multipotent adult stem cells (hAT-MASC) and embryonic carcinoma stem cells (EC) towards a neuronal phenotype.
  
  
  RESULTS
  Applying a definite protocol, hAT-MASC can adopt a neural fate. During this maturation process, differentiating cells significantly increase their intracellular Reactive Oxygen Species (ROS) levels and increase the APE1 nuclear fraction bound to chromatin. This latter event is paralleled by the increase of nuclear NF-κB, a transcription factor regulated by APE1 in a redox-dependent fashion. Importantly, the addition of the antioxidant N-acetyl cysteine (NAC) to the differentiation medium partially prevents the nuclear accumulation of APE1, increasing the neuronal differentiation of hAT-MASC. To investigate the involvement of APE1 in the differentiation process, we employed E3330, a specific inhibitor of the APE1 redox function. The addition of E3330, either to the neurogenic embryonic carcinoma cell line NT2-D1or to hAT-MASC, increases the differentiation of stem cells towards a neural phenotype, biasing the differentiation towards specific subtypes, such as dopaminergic cells. In conclusion, during the differentiation process of stem cells towards a neuroectodermic phenotype, APE1 is recruited, in a ROS-dependent manner, to the chromatin. This event is associated with an inhibitory effect of APE1 on neurogenesis that may be reversed by E3330. Therefore, E3330 may be employed both to boost neural differentiation and to bias the differentiation potential of stem cells towards specific neuronal subtypes. These findings provide a molecular basis for the redox-mediated hypothesis of neuronal differentiation program.
authors.affiliation: Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
authors.forename: Rossana
authors.initials: R
authors.lastname: Domenis
authors.affiliation: Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
authors.forename: Natascha
authors.initials: N
authors.lastname: Bergamin
authors.affiliation: Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
authors.forename: Giuseppe
authors.initials: G
authors.lastname: Gianfranceschi
authors.affiliation: Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
authors.forename: Carlo
authors.initials: C
authors.lastname: Vascotto
authors.affiliation: Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
authors.forename: Milena
authors.initials: M
authors.lastname: Romanello
authors.affiliation: Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
authors.forename: Silvia
authors.initials: S
authors.lastname: Rigo
authors.affiliation: Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
authors.forename: Giovanna
authors.initials: G
authors.lastname: Vagnarelli
authors.affiliation: Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
authors.forename: Massimo
authors.initials: M
authors.lastname: Faggiani
authors.affiliation: Department of Experimental and Clinical Medical Sciences, University of Udine, Udine, Italy.
authors.forename: Piercamillo
authors.initials: P
authors.lastname: Parodi
authors.affiliation: Department of Pediatrics (Section of Hematology/Oncology), Herman B. Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, Indiana, United States of America.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Kelley
authors.affiliation: Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
authors.forename: Carlo Alberto
authors.initials: CA
authors.lastname: Beltrami
authors.affiliation: Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
authors.forename: Daniela
authors.initials: D
authors.lastname: Cesselli
authors.affiliation: Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
authors.forename: Gianluca
authors.initials: G
authors.lastname: Tell
authors.affiliation: Department of Medical and Biological Sciences, University of Udine, Udine, Italy.
authors.forename: Antonio Paolo
authors.initials: AP
authors.lastname: Beltrami
mesh_terms: D000273:Adipose Tissue / Q000166:cytology*; D000328:Adult; D053687:Adult Stem Cells / Q000378:metabolism / Q000502:physiology*; D016227:Benzoquinones; D015153:Blotting, Western; D002454:Cell Differentiation / Q000502:physiology*; D002843:Chromatin / Q000378:metabolism; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase / Q000378:metabolism*; D005434:Flow Cytometry; D006801:Humans; D008856:Microscopy, Fluorescence; D039902:Multipotent Stem Cells / Q000378:metabolism / Q000502:physiology*; D016328:NF-kappa B / Q000378:metabolism; D055495:Neurogenesis / Q000502:physiology*; D010084:Oxidation-Reduction; D011422:Propionates; D017382:Reactive Oxygen Species / Q000378:metabolism; D060888:Real-Time Polymerase Chain Reaction; D020133:Reverse Transcriptase Polymerase Chain Reaction; D018709:Statistics, Nonparametric
chemical_list: D016227:Benzoquinones; D002843:Chromatin; D016328:NF-kappa B; D011422:Propionates; D017382:Reactive Oxygen Species; C075569:E 3330; C085108:APEX1 protein, human; D043603:DNA-(Apurinic or Apyrimidinic Site) Lyase