Overlapping representations of food and social stimuli in VTA dopamine neurons
Ontology highlight
ABSTRACT: We used 2-photon calcium imaging to determine whether the same or different dopamine neurons of the ventral tegmental area (VTADA) encode food and social stimuli, and found statistically significant overlap in the populations responsive to both stimuli. Both hunger and opposite-sex social experience increased the proportion of neurons that respond to both stimuli, implying that increasing motivation for one stimulus further increases overlap. We used single-nucleus RNA sequencing (snRNA-seq) to examine cell type-specific gene expression changes across different hunger states and the level of co-expression of feeding- and social-hormone related genes in individual VTADA neurons.
Project description:One great challenge in neuroscience is connecting molecular and cellular phenotypes to behavioral consequences. Using social motivation as a test case, we propose that individual behavioral trait variation can be leveraged to identify novel components of social reward circuits in the brain. Specifically, we hypothesized that either proportion or molecular features of distinct neuron classes in the hypothalamus can predict individual differences in social motivation. To test this, we generated high-precision single-nucleus RNA-sequencing profiles of >120,000 neurons from the hypothalamus and adjacent thalamus from 36 mice assessed for social motivation, balancing across sex and an autism-associated mutation genotype. Analysis of IEG patterns revealed that PVN Agtr1a+ neurons negatively predict social behavior. Consistent with this, FDA-approved AGTR1A antagonists increase social orienting. Next, analyzing neuronal subtype proportions as predictors of social behavior, we identified multiple neuronal populations whose relative abundance correlated with individual differences in social reward-seeking, particularly the Nxph4+ neurons of the posterior and lateral hypothalamus. Subsequent chemogenetic inhibition of these suppressed multiple aspects of social motivation. This work establishes a proof-of-principle for a new approach using single-cellsingle cell genomics to identify neural substrates for behavior and identifies cellular determinants of social motivation, which suggest therapeutic avenues for disorders with social deficits.
Project description:Implications for neuroprotection in Parkinson's disease Parkinson’s disease and its characteristic symptoms are thought to arise from the progressive degeneration of specific midbrain dopamine (DA) neurons. In humans, DA neurons of the substantia nigra (SN) and their projections to the striatum show selective vulnerability, while neighboring DA neurons of the ventral tegmental area (VTA) are relatively spared from degeneration. This pattern of cell loss is mimicked in humans, primates, and certain rodents by the neurotoxin MPTP. In this study, we aimed to test the hypothesis that there are factors in the VTA that are potentially neuroprotective against MPTP and that these factors change over time. We have found a differential transcriptional response within the cells of the SN and VTA to sustained exposure to a low dose of MPTP. Specifically, the VTA has increased expression of 148 genes as an early response to MPTP and 113 genes as a late response to MPTP toxicity. This response encompasses many areas of cellular function, including protein regulation (Phf6) and ion/metal regulation (PANK2, Car4). Notably, these responses were largely absent from the cells of the SN. Our data show a clear dynamic response in maintaining the homeostasis and viability of the neurons in the VTA that is lacking in the SN after neurotoxin challenge. We used microarrays to analyze the differential response of the substantia nigra (SN) and ventral tegmental area (VTA) to a chronic low dose of the neurotoxin MPTP. Transgenic hTH-GFP mice were treated with MPTP (4mg/kg) for either 2 or 10 days. Control mice were given an equal volume of saline for 10 days. Dopamine neurons from the substantia nigra and ventral tegmental areas of control and MPTP treated animals were laser captured. The RNA was isolated and processed for microarray hybridization. Each group had three biological replicates, for a total of 18 samples. Three each in the following: Control SN, Control VTA, 2 day MPTP SN, 2 day MPTP VTA, 10 day MPTP SN, 10 day MPTP VTA. Samples were log2 transformed and RMA normalized using Agilent Genespring 10.0 GX.
Project description:A substantial proportion of basal amygdala (BA) glutamate neurons project to nucleus accumbens (NAc). The evidence that these neurons are activated by reward and/or aversion is equivocal. Social stimuli are highly salient, and in male mice we conducted a detailed analysis of the responsiveness of BA-NAc neurons to estrous female (social reward, SR) or aggressive male (social aversion, SA). Both SR and SA activated c-Fos expression in a relatively high number of BA-NAc neurons in intermediate (int) BA. Using Fos-TRAP2 mice, the majority of social int-BA-NAc neurons were activated by either SR or SA, i.e. were monovalent, and in similar numbers. Fiber photometry provided corroborative evidence that int-BA-NAc neural pathway activity was similar in response to SR or SA. These findings contribute substantially to understanding the topography and valence-specificity of BA-NAc neurons with respect to highly salient stimuli, and to identifying molecular targets for treatment of reward- or aversion-specific psychopathologies.
Project description:We performed single nuclei transcriptomics of ventral tegmental area samples from rats sacrificed one hour after a single saline injection and profiled the cell types and their receptor composition.
Project description:Implications for neuroprotection in Parkinson's disease Parkinson’s disease and its characteristic symptoms are thought to arise from the progressive degeneration of specific midbrain dopamine (DA) neurons. In humans, DA neurons of the substantia nigra (SN) and their projections to the striatum show selective vulnerability, while neighboring DA neurons of the ventral tegmental area (VTA) are relatively spared from degeneration. This pattern of cell loss is mimicked in humans, primates, and certain rodents by the neurotoxin MPTP. In this study, we aimed to test the hypothesis that there are factors in the VTA that are potentially neuroprotective against MPTP and that these factors change over time. We have found a differential transcriptional response within the cells of the SN and VTA to sustained exposure to a low dose of MPTP. Specifically, the VTA has increased expression of 148 genes as an early response to MPTP and 113 genes as a late response to MPTP toxicity. This response encompasses many areas of cellular function, including protein regulation (Phf6) and ion/metal regulation (PANK2, Car4). Notably, these responses were largely absent from the cells of the SN. Our data show a clear dynamic response in maintaining the homeostasis and viability of the neurons in the VTA that is lacking in the SN after neurotoxin challenge. We used microarrays to analyze the differential response of the substantia nigra (SN) and ventral tegmental area (VTA) to a chronic low dose of the neurotoxin MPTP.
Project description:This study aimed at identifying rhythmically regulated transcripts in the ventral tegmental area (VTA) of mice. Punch biopsies of the VTA from C57BL/6 brain slices were prepared at 6 different timepoints across the day and analyzed for transcriptome regulation
Project description:Drugs of abuse including nicotine and alcohol elicit their effect by stimulating the mesocorticolimbic dopaminergic system. There is a high incidence of nicotine dependence in alcoholics. To date only limited data is available on the molecular mechanism underlying the action of alcohol and nicotine in the human brain. This study utilised gene expression screening to identify genes sensitive to chronic alcohol abuse within the ventral tegmental area of the human brain. Keywords: gene expression, brain, alcohol abuse, human, ventral tegmental area
Project description:Pitx3 is a transcription factor that is expressed in all midbrain dopaminergic (mDA) neurons during early development, but later becomes restricted in dopaminergic subsets of substantia nigra compacta (SNc) and of the ventral tegmental are (VTA) that are vulnerable to neurodegenerative stress (MPTP, 6-OHDA, rotenone, Parkinson's disease). Overall, in mice, Pitx3 is required for developmental survival of ventral SNc neurons and for postnatal survival of VTA neurons (after postnatal day 40). With the aim of determining the gene networks that distinguish Pitx3-vulnerable (Pitx3-positive) from Pitx3-resistant (Pitx3-negative) subsets of SNc and VTA, we performed a comparison at the transcriptome level between FAC-sorted mDA neurons of SNc and VTA that were obtained from wild-type and Pitx3-/- newborn mice. The latter mice have already lost the majority of their TH+Calb1- mDA neurons of ventral SNc (Pitx3-dependent), but their TH+Calb1+ neurons of dorsal SNc (Pitx3-independent), including all of VTA neurons (50% are Pitx3-dependent and 50% Pitx3-independent), are unaffected by Pitx3 deletion. At postnatal day 40, Pitx3-/- mice display a marked loss of dopaminergic subsets of VTA that normally co-express Pitx3 and Calb1 (Pitx3-dependent neurons of VTA).
Project description:The dorsal root ganglion (DRG) neurons take in charge of primary detection and transmission of peripheral pain and itch stimuli, however, as two distinct noxious sensation, it is still attractive for this field that how the DRG neurons differentially response and code pain and itch. Here, we investigate the response and activation spectrum of DRG neurons under peripheral pain and itch stimuli using in vivo two-photon calcium imaging, and find differences in the responsive intensity to pain and itch between multisensory neurons (both pain and itch) and single-sensory neurons (either pain or itch). Besides, single-cell RNA sequencing (scRNA-seq) is used to reveal the heterogeneity of distinct subpopulations based on their expression of pain- or itch-related marker genes and indicates the similarity and difference of their transcriptomic changes under chronic pain and itch. Our results will provide fundamental insights to the peripheral pain and itch differential coding mechanism, moreover, benefit the development of pain and itch therapies.