α-Synuclein expression in the mouse cerebellum is restricted to VGluT1 excitatory terminals and is enriched in unipolar brush cells.
α-Synuclein has a crucial role in synaptic vesicle release and synaptic membrane recycling. Although its general expression pattern has been described in the cerebellum, the precise cerebellar structures where α-synuclein is localized are poorly understood. To address this question, we used α-synuclein immunohistochemistry in adult mice cerebellar sections. We found that α-synuclein labels glutamatergic but not glycinergic and GABAergic synaptic terminals in the molecular and granule cell layers. α-Synuclein was preferentially expressed in parallel and mossy fiber synaptic terminals that also express vesicular glutamate transporter 1 (VGluT1), while it was not detected in VGluT2-positive climbing fibers. α-Synuclein was particularly enriched in lobules IX and X, a region known to contain a high density of unipolar brush cells (UBCs). To elucidate whether the α-synuclein-positive mossy fibers belong to UBCs, we double-labeled cerebellar sections with antibodies to α-synuclein and UBC-type-specific markers (calretinin for type I and metabotropic glutamate receptor 1α (mGluR1α) for type II UBCs) and took advantage of organotypic cerebellar cultures (in which all mossy fibers are UBC axons) and moonwalker mice (in which almost all UBCs are ablated) and found that both type I and type II UBCs express α-synuclein. In moonwalker mutant cerebella, the α-synuclein/VGluT1 immunolabeling showed a dramatic decrease in the vestibulocerebellum that correlated with the absence of UBC. α-Synuclein appears to be an excellent marker for intrinsic mossy fibers of the VGluT1 subset in conjunction with UBCs of both subtypes.
Department of Physiology, Feinberg School of Medicine, Northwestern University, Morton 5-619, Chicago, IL, 60611, USA.
Sun Kyong
SK
Lee
Department of Pathology and Immunology, Baylor College of Medicine, Jan and Dan Duncan Neurological Research Institute of Texas Children's Hospital, Houston, TX, 77030, USA.
Roy V
RV
Sillitoe
Department of Physiology, Feinberg School of Medicine, Northwestern University, Morton 5-619, Chicago, IL, 60611, USA.
Coralie
C
Silva
Department of Physiology, Feinberg School of Medicine, Northwestern University, Morton 5-619, Chicago, IL, 60611, USA.
Marco
M
Martina
Department of Physiology, Feinberg School of Medicine, Northwestern University, Morton 5-619, Chicago, IL, 60611, USA. g-sekerkova@northwestern.edu.
Gabriella
G
Sekerkova
D000818:Animals; D002531:Cerebellum / Q000166:cytology* / Q000378:metabolism*; D005260:Female; D005786:Gene Expression Regulation / Q000235:genetics; D005968:Glutamate Decarboxylase / Q000378:metabolism; D050487:Glycine Plasma Membrane Transport Proteins / Q000378:metabolism; D006360:Heat-Shock Proteins / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008817:Mice, Mutant Strains; D008822:Mice, Transgenic; D018832:Molecular Chaperones; D009154:Mutation / Q000235:genetics; D009363:Neoplasm Proteins / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000378:metabolism; D009474:Neurons / Q000378:metabolism*; D009924:Organ Culture Techniques; D017729:Presynaptic Terminals / Q000502:physiology*; D050052:TRPC Cation Channels / Q000235:genetics; D050598:Vesicular Glutamate Transport Protein 1 / Q000378:metabolism*; D051844:alpha-Synuclein / Q000235:genetics / Q000378:metabolism*
D050487:Glycine Plasma Membrane Transport Proteins; D006360:Heat-Shock Proteins; C486113:Hsbp1 protein, mouse; D018832:Molecular Chaperones; D009363:Neoplasm Proteins; D009419:Nerve Tissue Proteins; C493465:Slc17a7 protein, mouse; D050052:TRPC Cation Channels; C104603:TRPC3 cation channel; D050598:Vesicular Glutamate Transport Protein 1; D051844:alpha-Synuclein; D005968:Glutamate Decarboxylase; C402565:glutamate decarboxylase 1
Granule cells; Moonwalker mice; Mossy fiber terminals; VGluT1; VGluT2; Vestibulocerebellum