title: In vivo bioluminescence reporter gene imaging for the activation of neuronal differentiation induced by the neuronal activator neurogenin 1 (Ngn1) in neuronal precursor cells.
abstract: OBJECTIVE
  Facilitation of the ability of neuronal lineages derived from transplanted stem cells to differentiate is essential to improve the low efficacy of neuronal differentiation in stem cell therapy in vivo. Neurogenin 1 (Ngn1), a basic helix-loop-helix factor, has been used as an activator of neuronal differentiation. In this study, we monitored the in vivo activation of neuronal differentiation by Ngn1 in neuronal precursor cells using neuron-specific promoter-based optical reporters.
  
  
  METHODS
  The NeuroD promoter coupled with the firefly luciferase reporter system (pNeuroD-Fluc) was used to monitor differentiation in F11 neuronal precursor cells. In vitro luciferase activity was measured and normalized by protein content. The in vivo-jetPEI(TM) system was used for in vivo transgene delivery. The IVIS 100 imaging system was used to monitor in vivo luciferase activity.
  
  
  RESULTS
  The Ngn1-induced neuronal differentiation of F11 cells generated neurite outgrowth within 2 days of Ngn1 induction. Immunofluorescence staining demonstrated that early and late neuronal marker expression (βIII-tubulin, NeuroD, MAP2, NF-M, and NeuN) was significantly increased at 3 days after treatment with Ngn1. When Ngn1 and the pNeuroD-Fluc vector were cotransfected into F11 cells, we observed an approximately 11-fold increase in the luciferase signal. An in vivo study showed that bioluminescence signals were gradually increased in Ngn1-treated F11 cells for up to 3 days.
  
  
  CONCLUSIONS
  In this study, we examined the in vivo tracking of neuronal differentiation induced by Ngn1 using an optical reporter system. This reporter system could be used effectively to monitor the activation efficiency of neuronal differentiation in grafted stem cells treated with Ngn1 for stem cell therapy.
authors.affiliation: Department of Nuclear Medicine, College of Medicine, Seoul National University, 101 Daehak-ro, Jongno-gu, Seoul, 110-744, Korea.
authors.forename: Hyun Jeong
authors.initials: HJ
authors.lastname: Oh
authors.forename: Do Won
authors.initials: DW
authors.lastname: Hwang
authors.forename: Hyewon
authors.initials: H
authors.lastname: Youn
authors.forename: Dong Soo
authors.initials: DS
authors.lastname: Lee
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000235:genetics / Q000378:metabolism*; D017930:Genes, Reporter; D006367:HeLa Cells; D006801:Humans; D049409:Luciferases, Firefly / Q000235:genetics / Q000378:metabolism*; D051379:Mice; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism*; D058953:Neural Stem Cells / Q000166:cytology / Q000378:metabolism*; D055495:Neurogenesis; D061848:Optical Imaging; D011401:Promoter Regions, Genetic; D051381:Rats
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D049409:Luciferases, Firefly; D009419:Nerve Tissue Proteins; C486336:Neurog1 protein, mouse