title: (13) C magnetic resonance spectroscopy measurements with hyperpolarized [1-(13) C] pyruvate can be used to detect the expression of transgenic pyruvate decarboxylase activity in vivo.
abstract: Dissolution dynamic nuclear polarization can increase the sensitivity of the (13) C magnetic resonance spectroscopy experiment by at least four orders of magnitude and offers a novel approach to the development of MRI gene reporters based on enzymes that metabolize (13) C-labeled tracers. We describe here a gene reporter based on the enzyme pyruvate decarboxylase (EC 4.1.1.1), which catalyzes the decarboxylation of pyruvate to produce acetaldehyde and carbon dioxide.
  
  
  
  Pyruvate decarboxylase from Zymomonas mobilis (zmPDC) and a mutant that lacked enzyme activity were expressed using an inducible promoter in human embryonic kidney (HEK293T) cells. Enzyme activity was measured in the cells and in xenografts derived from the cells using (13) C MRS measurements of the conversion of hyperpolarized [1-(13) C] pyruvate to H(13) CO3-.
  
  
  
  Induction of zmPDC expression in the cells and in the xenografts derived from them resulted in an approximately two-fold increase in the H(13) CO3-/[1-(13) C] pyruvate signal ratio following intravenous injection of hyperpolarized [1-(13) C] pyruvate.
  
  
  
  We have demonstrated the feasibility of using zmPDC as an in vivo reporter gene for use with hyperpolarized (13) C MRS. Magn Reson Med 76:391-401, 2016. © 2015 The Authors. Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.|Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK.
authors.forename: Piotr
authors.initials: P
authors.lastname: Dzien
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.|Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK.
authors.forename: Sui-Seng
authors.initials: SS
authors.lastname: Tee
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.|Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK.
authors.forename: Mikko I
authors.initials: MI
authors.lastname: Kettunen
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.|Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK.
authors.forename: Scott K
authors.initials: SK
authors.lastname: Lyons
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Larkin
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.
authors.forename: Kerstin N
authors.initials: KN
authors.lastname: Timm
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.|Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK.
authors.forename: De-En
authors.initials: DE
authors.lastname: Hu
authors.affiliation: Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK.
authors.forename: Alan
authors.initials: A
authors.lastname: Wright
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.|Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK.
authors.forename: Tiago B
authors.initials: TB
authors.lastname: Rodrigues
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.|Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK.
authors.forename: Eva M
authors.initials: EM
authors.lastname: Serrao
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.
authors.forename: Irene
authors.initials: I
authors.lastname: Marco-Rius
authors.affiliation: Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK.
authors.forename: Elizabeth
authors.initials: E
authors.lastname: Mannion
authors.affiliation: Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK.
authors.forename: Paula
authors.initials: P
authors.lastname: D'Santos
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.
authors.forename: Brett W C
authors.initials: BW
authors.lastname: Kennedy
authors.affiliation: Department of Biochemistry, University of Cambridge, Cambridge, UK.|Cancer Research UK, Cambridge Research Institute, Li Ka Shing Centre, Cambridge, UK.
authors.forename: Kevin M
authors.initials: KM
authors.lastname: Brindle
mesh_terms: D000818:Animals; D066241:Carbon-13 Magnetic Resonance Spectroscopy / Q000379:methods*; D004789:Enzyme Activation; D005260:Female; D017930:Genes, Reporter / Q000502:physiology; D057809:HEK293 Cells; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D051379:Mice; D016513:Mice, SCID; D057054:Molecular Imaging / Q000379:methods*; D011767:Pyruvate Decarboxylase / Q000378:metabolism*; D019289:Pyruvic Acid / Q000493:pharmacokinetics*; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D014018:Tissue Distribution; D017355:Zymomonas / Q000201:enzymology* / Q000235:genetics
chemical_list: D011994:Recombinant Proteins; D019289:Pyruvic Acid; D011767:Pyruvate Decarboxylase
keywords: Zymomonas mobilis pyruvate decarboxylase; hyperpolarized [1-13C] pyruvate; reporter genes