A novel dopamine transporter transgenic mouse line for identification and purification of midbrain dopaminergic neurons reveals midbrain heterogeneity.
Midbrain dopaminergic (DAergic) neurons are a heterogeneous cell group, composed of functionally distinct cell populations projecting to the basal ganglia, prefrontal cortex and limbic system. Despite their functional significance, the midbrain population of DAergic neurons is sparse, constituting only 20 000-30 000 neurons in mice, and development of novel tools to identify these cells is warranted. Here, a bacterial artificial chromosome mouse line [Dat1-enhanced green fluorescent protein (eGFP)] from the Gene Expression Nervous System Atlas (GENSAT) that expresses eGFP under control of the dopamine transporter (DAT) promoter was characterized. Confocal microscopy analysis of brain sections showed strong eGFP signal reporter in midbrain regions and striatal terminals that co-localized with the DAergic markers DAT and tyrosine hydroxylase (TH). Thorough quantification of co-localization of the eGFP reporter signal with DAT and TH in the ventral midbrain showed that a vast majority of eGFP-expressing neurons are DAergic. Importantly, expression profiles also revealed DAergic heterogeneity when comparing substantia nigra and ventral tegmental area. Dat1-eGFP mice showed neither change in synaptosomal DA uptake nor altered levels of DAT and TH in both striatum and midbrain. No behavioural difference between Dat1-eGFP and wild-type was found, suggesting that the strain is not aberrant. Finally, cell populations highly enriched in DAergic neurons can be obtained from postnatal mice by fluorescence-activated cell sorting and the sorted neurons can be cultured in vitro. The current investigation demonstrates that eGFP expression in this mouse line is selective for DAergic neurons, suggesting that the Dat1-eGFP mouse strain constitutes a promising tool for delineating new aspects of DA biology.
Department of Neuroscience and Pharmacology, Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Mia
M
Apuschkin
Department of Neuroscience and Pharmacology, Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Sara
S
Stilling
Department of Neuroscience and Pharmacology, Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Troels
T
Rahbek-Clemmensen
Department of Neuroscience and Pharmacology, Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.|Department of Neuroscience and Pharmacology, Laboratory of Neuropsychiatry, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Gunnar
G
Sørensen
Department of Pharmacology and Groupe de Recherche sur le Système Nerveux Central, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada.
Guillaume
G
Fortin
Department of Neuroscience and Pharmacology, Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Freja
F
Herborg Hansen
Department of Neuroscience and Pharmacology, Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Jacob
J
Eriksen
Department of Pharmacology and Groupe de Recherche sur le Système Nerveux Central, Faculty of Medicine, Université de Montréal, Montréal, Québec, Canada.
Louis-Eric
LE
Trudeau
Department of Neuroscience and Pharmacology, Molecular Pharmacology Laboratory, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.|Section for Metabolic Receptology and Enteroendocrinology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Kristoffer
K
Egerod
Department of Neuroscience and Pharmacology, Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Ulrik
U
Gether
Department of Neuroscience and Pharmacology, Molecular Neuropharmacology and Genetics Laboratory, Lundbeck Foundation Center for Biomembranes in Nanomedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
Mattias
M
Rickhag
D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D050483:Dopamine Plasma Membrane Transport Proteins / Q000235:genetics / Q000378:metabolism*; D059290:Dopaminergic Neurons / Q000378:metabolism*; D005260:Female; D005434:Flow Cytometry; D049452:Green Fluorescent Proteins / Q000235:genetics; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008822:Mice, Transgenic; D013574:Synaptosomes / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism; D017557:Ventral Tegmental Area / Q000378:metabolism*
D050483:Dopamine Plasma Membrane Transport Proteins; C493215:Slc6a3 protein, mouse; C485184:enhanced green fluorescent protein; D049452:Green Fluorescent Proteins; D014446:Tyrosine 3-Monooxygenase
dopaminergic cultures; enhanced green fluorescent protein; fluorescence-activated cell sorting; transgenic mice; ventral midbrain