title: Down-regulation of microRNA-21 is involved in the propofol-induced neurotoxicity observed in human stem cell-derived neurons.
abstract: BACKGROUND
  Recent studies in various animal models have suggested that anesthetics such as propofol, when administered early in life, can lead to neurotoxicity. These studies have raised significant safety concerns regarding the use of anesthetics in the pediatric population and highlight the need for a better model to study anesthetic-induced neurotoxicity in humans. Human embryonic stem cells are capable of differentiating into any cell type and represent a promising model to study mechanisms governing anesthetic-induced neurotoxicity.
  
  
  METHODS
  Cell death in human embryonic stem cell-derived neurons was assessed using terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate in situ nick end labeling staining, and microRNA expression was assessed using quantitative reverse transcription polymerase chain reaction. miR-21 was overexpressed and knocked down using an miR-21 mimic and antagomir, respectively. Sprouty 2 was knocked down using a small interfering RNA, and the expression of the miR-21 targets of interest was assessed by Western blot.
  
  
  RESULTS
  Propofol dose and exposure time dependently induced significant cell death (n = 3) in the neurons and down-regulated several microRNAs, including miR-21. Overexpression of miR-21 and knockdown of Sprouty 2 attenuated the increase in terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate in situ nick end labeling-positive cells following propofol exposure. In addition, miR-21 knockdown increased the number of terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate in situ nick end labeling-positive cells by 30% (n = 5). Finally, activated signal transducer and activator of transcription 3 and protein kinase B (Akt) were down-regulated, and Sprouty 2 was up-regulated following propofol exposure (n = 3).
  
  
  CONCLUSIONS
  These data suggest that (1) human embryonic stem cell-derived neurons represent a promising in vitro human model for studying anesthetic-induced neurotoxicity, (2) propofol induces cell death in human embryonic stem cell-derived neurons, and (3) the propofol-induced cell death may occur via a signal transducer and activator of transcription 3/miR-21/Sprouty 2-dependent mechanism.
authors.affiliation: From the Departments of Physiology and Anesthesiology (D.M.T., J.M.O., Z.J.B.) and the Department of Anesthesiology (Y.Y., X.B.), Medical College of Wisconsin, Milwaukee, Wisconsin.
authors.forename: Danielle M
authors.initials: DM
authors.lastname: Twaroski
authors.forename: Yasheng
authors.initials: Y
authors.lastname: Yan
authors.forename: Jessica M
authors.initials: JM
authors.lastname: Olson
authors.forename: Zeljko J
authors.initials: ZJ
authors.lastname: Bosnjak
authors.forename: Xiaowen
authors.initials: X
authors.lastname: Bai
mesh_terms: D018686:Anesthetics, Intravenous / Q000633:toxicity*; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects / Q000502:physiology; D018920:Coculture Techniques; D004305:Dose-Response Relationship, Drug; D015536:Down-Regulation / Q000187:drug effects / Q000502:physiology*; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000378:metabolism*; D058953:Neural Stem Cells / Q000187:drug effects / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D015742:Propofol / Q000633:toxicity*
chemical_list: D018686:Anesthetics, Intravenous; C524940:MIRN21 microRNA, human; D035683:MicroRNAs; D015742:Propofol