title: FRET based ratiometric Ca(2+) imaging to investigate immune-mediated neuronal and axonal damage processes in experimental autoimmune encephalomyelitis.
abstract: BACKGROUND
  Irreversible axonal and neuronal damage are the correlate of disability in patients suffering from multiple sclerosis (MS). A sustained increase of cytoplasmic free [Ca(2+)] is a common upstream event of many neuronal and axonal damage processes and could represent an early and potentially reversible step.
  
  
  METHODS
  We propose a method to specifically analyze the neurodegenerative aspects of experimental autoimmune encephalomyelitis by Förster Resonance Energy Transfer (FRET) imaging of neuronal and axonal Ca(2+) dynamics by two-photon laser scanning microscopy (TPLSM).
  
  
  RESULTS
  Using the genetically encoded Ca(2+) sensor TN-XXL expressed in neurons and their corresponding axons, we confirm the increase of cytoplasmic free [Ca(2+)] in axons and neurons of autoimmune inflammatory lesions compared to those in non-inflamed brains. We show that these relative [Ca(2+)] increases were associated with immune-neuronal interactions.
  
  
  METHODS
  In contrast to Ca(2+)-sensitive dyes the use of a genetically encoded Ca(2+) sensor allows reliable intraaxonal free [Ca(2+)] measurements in living anesthetized mice in health and disease. This method detects early axonal damage processes in contrast to e.g. cell/axon morphology analysis, that rather detects late signs of neurodegeneration.
  
  
  CONCLUSIONS
  Thus, we describe a method to analyze and monitor early neuronal damage processes in the brain in vivo.
authors: Neurology Department, University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany. Electronic address: siffrinv@gmx.de.
authors: Volker
authors: V
authors: Siffrin
authors: Neurology Department, University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany.
authors: Jérôme
authors: J
authors: Birkenstock
authors: Neurology Department, University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany.
authors: Dirk W
authors: DW
authors: Luchtman
authors: Neurology Department, University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany.
authors: René
authors: R
authors: Gollan
authors: Central Research Animal Facility, University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany.
authors: Jan
authors: J
authors: Baumgart
authors: German Rheumatism Research Center, 10117 Berlin, Germany.
authors: Raluca A
authors: RA
authors: Niesner
authors: Max Planck Institute of Neurobiology, 82152 Martinsried, Germany.
authors: Oliver
authors: O
authors: Griesbeck
authors: Neurology Department, University Medical Center of the Johannes Gutenberg University Mainz, 55131 Mainz, Germany.
authors: Frauke
authors: F
authors: Zipp
mesh_terms: D000818:Animals; D001369:Axons / Q000473:pathology; D001933:Brain Stem / Q000473:pathology*; D002118:Calcium; D004681:Encephalomyelitis, Autoimmune, Experimental / Q000473:pathology*; D031541:Fluorescence Resonance Energy Transfer / Q000379:methods*; D051379:Mice; D018613:Microscopy, Confocal; D009474:Neurons / Q000473:pathology*
chemical_list: D002118:Calcium
keywords: Ca(2+) imaging neurodegeneration; EAE/MS; FRET; Intravital microscopy; Two-photon laser scanning microscopy