Functions of VAMP proteins in glial cells
Final Report Abstract
Role of VAMP proteins in glia cells of the retina. A key question in neuroscience is how neurons and glial cells interact to assure the function of the central nervous system. We studied whether glial cells influence neurons by the vesicular release of substances. This hypothesis was based on results obtained with cultured glial cells, and its validity in living animals has remained controversial. To address this point, genetically modified mice were developed to inhibit the vesicular release from glial cells in vivo. These models targeted specific vesicle-associated membrane proteins (VAMPs). VAMPs are components of the molecular machinery that mediates the fusion of cellular membranes and the release of substances. Mice lacking VAMP1-3 in glial cells showed only very small changes in brain function. A possible explanation was that other members of the VAMP family replaced the function of the missing VAMPs. In our project, we proposed to study the role of VAMP7. This candidate protein mediates specific pathways of vesicle trafficking in cells, but its role in glial cells is largely unknown. Analysis of VAMP functions in glial cells using new cell isolation methods and cellspecific gene manipulation. We studied the functions of specific members of the VAMP family in glial cells using a combination of new and established methods. This includes genetically modified mice, which lack VAMP7 in all cells, and mice, which lack VAMP1-3 specifically in glial cells. We determined how absence of these proteins affects brain structure using classic approaches including histology, immunohistochemistry and electron microscopy. Importantly, we took advantage of an innovative new method established by the German partner to strongly enrich specific types of cells including neurons and glial cells. This allowed us for the first time to determine the molecular properties of each cell type by mass spectrometry and RNAsequencing. For example, we could measure how the presence or absence of different VAMP proteins in glial cells affected their gene expression or protein profiles. These cellspecific analyses are very important, because changes in a specific cell type cannot be revealed by analyses of whole brain samples. Major results. Our project provides new insight in the distribution and functions of VAMP proteins in glial cells that will be explored by a follow-up study. Retinal glial cells express three specific members of the family of VAMPs. Their subcellular location suggests that they mediate communication with neurons in an unexpected manner. The elimination of VAMP1-3 and 7 from glial cells did not induce major changes in the retina, but slowed down the loss of neurons after ischemia. This suggests a contribution of glial vesicular release to pathologic changes.
Publications
- (2017) Suppression of SNARE-dependent exocytosis in retinal glial cells and its effect on ischemia-induced neurodegeneration. Glia 65 (7) 1059–1071
Wagner L, Pannicke T, Rupprecht V, Frommherz I, Volz C, Illes P, Hirrlinger J, Jägle H, Egger V, Haydon PG, Pfrieger FW, Grosche A.
(See online at https://doi.org/10.1002/glia.23144) - 18th Internatinal Microscopy Congress, Prague, Czec Repulic. The use of confocal laser scanning microscopy to study the morphology and function of astrocytes
Grosche A, Grosche J, Pfrieger FW, Pekny M, Reichenbach A
- X. International ProRetina Research Colloquium, Potsdam, Germany, 2015. VAMP expression in murine healthy and gliotic Müller cells
Hauser A, Barthelemy A, Demais V, Hauck S, Pfrieger FW, Grosche A
- XII European Meeting on Glial Cells in Health and Disease in Bilbao in July 2015, Vamp expression in healthy and gliotic murine Müller glia cells
Hauser A, Barthelemy A, Demais V, Pfrieger FW, Grosche A
- NEURONUS 2016 IBRO & IRUN Neuroscience Forum, Krakow, Poland. The Müller cell – the glial all-rounder of the retina
Pannicke T, Pfrieger FW, Slezak M, Haydon RG, Grosche A
- XII. PRO RETINA Research Colloquium, Potsdam Germany, 2017. Suppression of SNARE-dependent exocytosis in retinal glial cells and its effects on ischemia-induced neurodegeneration
Wagner L, Pannicke T, Volz C, Hirrlinger J, Jägle H, Haydon H, Pfrieger FW, Grosche A
