title: Using exomarkers to assess mitochondrial reactive species in vivo.
abstract: BACKGROUND
  The ability to measure the concentrations of small damaging and signalling molecules such as reactive oxygen species (ROS) in vivo is essential to understanding their biological roles. While a range of methods can be applied to in vitro systems, measuring the levels and relative changes in reactive species in vivo is challenging.
  
  
  METHODS
  One approach towards achieving this goal is the use of exomarkers. In this, exogenous probe compounds are administered to the intact organism and are then transformed by the reactive molecules in vivo to produce a diagnostic exomarker. The exomarker and the precursor probe can be analysed ex vivo to infer the identity and amounts of the reactive species present in vivo. This is akin to the measurement of biomarkers produced by the interaction of reactive species with endogenous biomolecules.
  
  
  CONCLUSIONS
  Our laboratories have developed mitochondria-targeted probes that generate exomarkers that can be analysed ex vivo by mass spectrometry to assess levels of reactive species within mitochondria in vivo. We have used one of these compounds, MitoB, to infer the levels of mitochondrial hydrogen peroxide within flies and mice. Here we describe the development of MitoB and expand on this example to discuss how better probes and exomarkers can be developed. This article is part of a Special Issue entitled Current methods to study reactive oxygen species - pros and cons and biophysics of membrane proteins. Guest Editor: Christine Winterbourn.
authors.affiliation: MRC Mitochondrial Biology Unit, Hills Road, Cambridge CB2 0XY, UK.
authors.forename: Angela
authors.initials: A
authors.lastname: Logan
authors.forename: Helena M
authors.initials: HM
authors.lastname: Cochemé
authors.forename: Pamela Boon
authors.initials: PB
authors.lastname: Li Pun
authors.forename: Nadezda
authors.initials: N
authors.lastname: Apostolova
authors.forename: Robin A J
authors.initials: RA
authors.lastname: Smith
authors.forename: Lesley
authors.initials: L
authors.lastname: Larsen
authors.forename: David S
authors.initials: DS
authors.lastname: Larsen
authors.forename: Andrew M
authors.initials: AM
authors.lastname: James
authors.forename: Ian M
authors.initials: IM
authors.lastname: Fearnley
authors.forename: Sebastian
authors.initials: S
authors.lastname: Rogatti
authors.forename: Tracy A
authors.initials: TA
authors.lastname: Prime
authors.forename: Peter G
authors.initials: PG
authors.lastname: Finichiu
authors.forename: Anna
authors.initials: A
authors.lastname: Dare
authors.forename: Edward T
authors.initials: ET
authors.lastname: Chouchani
authors.forename: Victoria R
authors.initials: VR
authors.lastname: Pell
authors.forename: Carmen
authors.initials: C
authors.lastname: Methner
authors.forename: Caroline
authors.initials: C
authors.lastname: Quin
authors.forename: Stephen J
authors.initials: SJ
authors.lastname: McQuaker
authors.forename: Thomas
authors.initials: T
authors.lastname: Krieg
authors.forename: Richard C
authors.initials: RC
authors.lastname: Hartley
authors.forename: Michael P
authors.initials: MP
authors.lastname: Murphy
mesh_terms: D000818:Animals; D015415:Biomarkers / Q000032:analysis*; D051379:Mice; D008928:Mitochondria / Q000378:metabolism*; D008954:Models, Biological; D015335:Molecular Probes; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000032:analysis*
chemical_list: D015415:Biomarkers; D015335:Molecular Probes; D017382:Reactive Oxygen Species
keywords: (3-hydroxybenzyl)triphenylphosphonium bromide; 3-(dihydroxyboronyl)benzyltriphenylphosphonium bromide; 4-HNE; 4-hydroxynonenal; EPR; Exomarker; GFP; Mass spectrometry; MitoB; MitoP; Mitochondria; Oxidative damage; ROS; Reactive oxygen species; SOD; TPMP; TPP; electron paramagnetic resonance; green fluorescent protein; methyltriphenylphosphonium; reactive oxygen species; superoxide dismutase; triphenylphosphonium cation