Nanoscopic distribution of VAChT and VGLUT3 in striatal cholinergic varicosities suggests colocalization and segregation of the two transporters in synaptic vesicles

Paola Cristofari (1, 2) , Mazarine Desplanque (1, 2) , Odile Poirel (1, 2) , Alison Hébert (1, 2) , Sylvie Dumas (3) , Etienne Herzog (4) , Lydia Danglot (5, 6) , David Geny (5) , Jean-François Gilles , Audrey Geeverding (7, 8) , Susanne Bolte (9, 10) , Alexis Canette (7, 8) , Michaël Trichet (7, 8) , Véronique Fabre (1, 2) , Stéphanie Daumas (1, 9, 2) , Nicolas Pietrancosta (11, 9, 2) , Salah El Mestikawy (1, 9, 12, 2) , Véronique Bernard (1, 2)

1 NPS - Neuroscience Paris Seine
2 NPS - Systèmes glutamatergiques normaux et pathologiques = Normal and Pathologic Glutamatergic Neurons
3 Oramacell [Paris, France]
4 IINS - Interdisciplinary Institute for Neuroscience [Bordeaux]
5 IPNP - U1266 Inserm - Institut de psychiatrie et neurosciences de Paris
6 GHU Paris Psychiatrie et Neurosciences
7 IBPS-ME - Microscopie Electronique [IBPS]
8 SU - Sorbonne Université
9 IBPS - Institut de Biologie Paris Seine
10 IBPS-IP - Imagerie Cellulaire et Cytométrie de Flux [IBPS]
11 LBM UMR 7203 - Laboratoire des biomolécules
12 McGill University = Université McGill [Montréal, Canada]

Striatal cholinergic interneurons (CINs) use acetylcholine (ACh) and glutamate (Glut) to regulate the striatal network since they express vesicular transporters for ACh (VAChT) and Glut (VGLUT3). However, whether ACh and Glut are released simultaneously and/or independently from cholinergic varicosities is an open question. The answer to that question requires the multichannel detection of vesicular transporters at the level of single synaptic vesicle (SV). Here, we used super-resolution STimulated Emission Depletion microscopy (STED) to characterize and quantify the distribution of VAChT and VGLUT3 in CINs SVs. Nearest-neighbor distances analysis between VAChT and VGLUT3-immunofluorescent spots revealed that 34% of CINs SVs contain both VAChT and VGLUT3. In addition, 40% of SVs expressed only VAChT while 26% of SVs contain only VGLUT3. These results suggest that SVs from CINs have the potential to store simultaneously or independently ACh and/or Glut. Overall, these morphological findings support the notion that CINs varicosities can signal with either ACh or Glut or both with an unexpected level of complexity.

Mots clés: Striatum; striatal cholinergic interneurons; acetylcholine-glutamate cotransmission; vesicular acetylcholine transporter; VAChT; Type 3 vesicular glutamate transporter; VGLUT3; scanning electron microscopy (SEM); STimulated Emission Depletion microscopy (STED)

Domaines: Neurosciences [q-bio.NC]

Paola Cristofari, Mazarine Desplanque, Odile Poirel, Alison Hébert, Sylvie Dumas, et al.. Nanoscopic distribution of VAChT and VGLUT3 in striatal cholinergic varicosities suggests colocalization and segregation of the two transporters in synaptic vesicles. Frontiers in Molecular Neuroscience, 2022, 15, pp.991732. ⟨10.3389/fnmol.2022.991732⟩. ⟨hal-03797259⟩