title: Monitoring Ca2+elevations in individual astrocytes upon local release of amyloid beta in acute brain slices.
abstract: The pathogenesis of Alzheimer's disease (AD) is thought to involve acute neurotoxic effects exerted by oligomeric forms of amyloid-β 1-42 (Aβ). Application of Aβ oligomers in physiological concentrations have been shown to transiently elevate internal Ca2+in cultured astroglia. While the cellular machinery involved has been extensively explored, to what degree this important signalling cascade occurs in organised brain tissue has remained unclear. Here we adapted two-photon excitation microscopy and calibrated time-resolved imaging (FLIM), coupled with patch-clamp electrophysiology, to monitor Ca2+concentration ([Ca2+]) inside individual astrocytes and principal neurons in acute brain slices. Inside the slice tissue local micro-ejection of Aβ in sub-micromolar concentrations triggered prominent [Ca2+] elevations in an adjacent astrocyte translated as an approximately two-fold increase (averaged over ∼5min) in basal [Ca2+]. This elevation did not spread to neighbouring cells and appeared comparable in amplitude with commonly documented spontaneous [Ca2+] rises in astroglia. Principal nerve cells (pyramidal neurons) also showed Ca2+sensitivity, albeit to a lesser degree. These observations shed light on the extent and dynamics of the acute physiological effects of Aβ on brain cells in situ, in the context of AD.
authors.affiliation: UCL Institute of Neurology, University College London, Queen Square, London WC1 3BG, UK; Institute of Neuroscience, University of Nizhny Novgorod, 603950 Nizhny Novgorod, Russia.
authors.forename: Olga
authors.initials: O
authors.lastname: Tyurikova
authors.affiliation: UCL Institute of Neurology, University College London, Queen Square, London WC1 3BG, UK.
authors.forename: Kaiyu
authors.initials: K
authors.lastname: Zheng
authors.affiliation: UCL Institute of Neurology, University College London, Queen Square, London WC1 3BG, UK.
authors.forename: Annika
authors.initials: A
authors.lastname: Rings
authors.affiliation: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK.
authors.forename: Anna
authors.initials: A
authors.lastname: Drews
authors.affiliation: Department of Chemistry, University of Cambridge, Lensfield Road, Cambridge, UK.
authors.forename: David
authors.initials: D
authors.lastname: Klenerman
authors.affiliation: UCL Institute of Neurology, University College London, Queen Square, London WC1 3BG, UK. Electronic address: d.rusakov@ucl.ac.uk.
authors.forename: Dmitri A
authors.initials: DA
authors.lastname: Rusakov
mesh_terms: D016229:Amyloid beta-Peptides / Q000008:administration & dosage / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000187:drug effects / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002413:Cations, Divalent / Q000378:metabolism; D002491:Central Nervous System Agents / Q000008:administration & dosage; D006624:Hippocampus / Q000187:drug effects / Q000378:metabolism*; D008564:Membrane Potentials / Q000187:drug effects / Q000502:physiology; D008856:Microscopy, Fluorescence; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D018408:Patch-Clamp Techniques; D010446:Peptide Fragments / Q000008:administration & dosage / Q000378:metabolism*; D017207:Rats, Sprague-Dawley; D059010:Single-Cell Analysis; D046509:Tissue Culture Techniques
chemical_list: D016229:Amyloid beta-Peptides; D002413:Cations, Divalent; D002491:Central Nervous System Agents; D010446:Peptide Fragments; C075222:amyloid beta-protein (1-42); D002118:Calcium
keywords: Amyloid beta; Astroglia; Calcium imaging; Fluorescence lifetime imaging; Hippocampus