title: Astrocyte VAMP3 vesicles undergo Ca2+ -independent cycling and modulate glutamate transporter trafficking.
abstract: CONCLUSIONS
  Mouse cortical astrocytes express VAMP3 but not VAMP2. VAMP3 vesicles undergo Ca(2+) -independent exo- and endocytotic cycling at the plasma membrane. VAMP3 vesicle traffic regulates the recycling of plasma membrane glutamate transporters. cAMP modulates VAMP3 vesicle cycling and glutamate uptake.
  Previous studies suggest that small synaptic-like vesicles in astrocytes carry vesicle-associated vSNARE proteins, VAMP3 (cellubrevin) and VAMP2 (synaptobrevin 2), both contributing to the Ca(2+) -regulated exocytosis of gliotransmitters, thereby modulating brain information processing. Here, using cortical astrocytes taken from VAMP2 and VAMP3 knock-out mice, we find that astrocytes express only VAMP3. The morphology and function of VAMP3 vesicles were studied in cultured astrocytes at single vesicle level with stimulated emission depletion (STED) and total internal reflection fluorescence (TIRF) microscopies. We show that VAMP3 antibodies label small diameter (∼80 nm) vesicles and that VAMP3 vesicles undergo Ca(2+) -independent exo-endocytosis. We also show that this pathway modulates the surface expression of plasma membrane glutamate transporters and the glutamate uptake by astrocytes. Finally, using pharmacological and optogenetic tools, we provide evidence suggesting that the cytosolic cAMP level influences astrocytic VAMP3 vesicle trafficking and glutamate transport. Our results suggest a new role for VAMP3 vesicles in astrocytes.
authors: CNRS UMR 8118, Paris, F-75006 France; Brain Physiology Laboratory, Saints-Pères Research in Neurosciences Federation, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France.|INSERM U603, Paris, F-75006 France; CNRS UMR 8154, Paris, F-75006 France, Neurophysiology and New Microscopies Laboratory, 45 rue des Saints Pères, Paris, F-75006, France.
authors: Dongdong
authors: D
authors: Li
authors: CNRS UMR 8118, Paris, F-75006 France; Brain Physiology Laboratory, Saints-Pères Research in Neurosciences Federation, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France.
authors: Karine
authors: K
authors: Hérault
authors: INSERM ERL U950, Paris, F-75013, France.|Université Paris Diderot, Sorbonne Paris Cité, Paris, F-75013, France.|CNRS, UMR 7592, Institut Jacques Monod, Paris, F-75013, France.
authors: Kathleen
authors: K
authors: Zylbersztejn
authors: Neurophotonics Laboratory, CNRS UMR 8250, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France.
authors: Marcel A
authors: MA
authors: Lauterbach
authors: Neurophotonics Laboratory, CNRS UMR 8250, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France.
authors: Marc
authors: M
authors: Guillon
authors: CNRS UMR 8118, Paris, F-75006 France; Brain Physiology Laboratory, Saints-Pères Research in Neurosciences Federation, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France.|INSERM U603, Paris, F-75006 France; CNRS UMR 8154, Paris, F-75006 France, Neurophysiology and New Microscopies Laboratory, 45 rue des Saints Pères, Paris, F-75006, France.
authors: Martin
authors: M
authors: Oheim
authors: CNRS UMR 8118, Paris, F-75006 France; Brain Physiology Laboratory, Saints-Pères Research in Neurosciences Federation, Université Paris Descartes, Sorbonne Paris Cité, 45 rue des Saints Pères, Paris, F-75006, France.|INSERM U603, Paris, F-75006 France; CNRS UMR 8154, Paris, F-75006 France, Neurophysiology and New Microscopies Laboratory, 45 rue des Saints Pères, Paris, F-75006, France.
authors: Nicole
authors: N
authors: Ropert
mesh_terms: D027322:Amino Acid Transport System X-AG / Q000378:metabolism*; D000818:Animals; D001253:Astrocytes / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002540:Cerebral Cortex / Q000166:cytology / Q000378:metabolism; D004705:Endocytosis; D005089:Exocytosis; D051379:Mice; D021381:Protein Transport; D022161:Transport Vesicles / Q000378:metabolism*; D051040:Vesicle-Associated Membrane Protein 3 / Q000378:metabolism*
chemical_list: D027322:Amino Acid Transport System X-AG; D051040:Vesicle-Associated Membrane Protein 3; C494953:vesicle-associated membrane protein 3, mouse; D002118:Calcium