-
Cell Oct 2016Understanding human embryonic ventral midbrain is of major interest for Parkinson's disease. However, the cell types, their gene expression dynamics, and their... (Comparative Study)
Comparative Study
Understanding human embryonic ventral midbrain is of major interest for Parkinson's disease. However, the cell types, their gene expression dynamics, and their relationship to commonly used rodent models remain to be defined. We performed single-cell RNA sequencing to examine ventral midbrain development in human and mouse. We found 25 molecularly defined human cell types, including five subtypes of radial glia-like cells and four progenitors. In the mouse, two mature fetal dopaminergic neuron subtypes diversified into five adult classes during postnatal development. Cell types and gene expression were generally conserved across species, but with clear differences in cell proliferation, developmental timing, and dopaminergic neuron development. Additionally, we developed a method to quantitatively assess the fidelity of dopaminergic neurons derived from human pluripotent stem cells, at a single-cell level. Thus, our study provides insight into the molecular programs controlling human midbrain development and provides a foundation for the development of cell replacement therapies.
Topics: Animals; Cell Line; Cellular Reprogramming Techniques; Dopaminergic Neurons; Humans; Machine Learning; Mesencephalon; Mice; Neural Stem Cells; Neurogenesis; Neuroglia; Pluripotent Stem Cells; Sequence Analysis, RNA; Single-Cell Analysis
PubMed: 27716510
DOI: 10.1016/j.cell.2016.09.027 -
Cell Stem Cell Apr 2023The cell lineages across developmental stages remain to be elucidated. Here, we developed single-cell split barcoding (SISBAR) that allows clonal tracking of single-cell...
The cell lineages across developmental stages remain to be elucidated. Here, we developed single-cell split barcoding (SISBAR) that allows clonal tracking of single-cell transcriptomes across stages in an in vitro model of human ventral midbrain-hindbrain differentiation. We developed "potential-spective" and "origin-spective" analyses to investigate the cross-stage lineage relationships and mapped a multi-level clonal lineage landscape depicting the whole differentiation process. We uncovered many previously uncharacterized converging and diverging trajectories. Furthermore, we demonstrate that a transcriptome-defined cell type can arise from distinct lineages that leave molecular imprints on their progenies, and the multilineage fates of a progenitor cell-type represent the collective results of distinct rather than similar clonal fates of individual progenitors, each with distinct molecular signatures. Specifically, we uncovered a ventral midbrain progenitor cluster as the common clonal origin of midbrain dopaminergic (mDA) neurons, midbrain glutamatergic neurons, and vascular and leptomeningeal cells and identified a surface marker that can improve graft outcomes.
Topics: Humans; Cell Differentiation; Mesencephalon; Stem Cells; Neurons; Cell Lineage
PubMed: 36933556
DOI: 10.1016/j.stem.2023.02.007 -
Neuron Jan 2019Ventral tegmental area (VTA) dopamine (DA) neurons play a central role in mediating motivated behaviors, but the circuitry through which they signal positive and...
Ventral tegmental area (VTA) dopamine (DA) neurons play a central role in mediating motivated behaviors, but the circuitry through which they signal positive and negative motivational stimuli is incompletely understood. Using in vivo fiber photometry, we simultaneously recorded activity in DA terminals in different nucleus accumbens (NAc) subnuclei during an aversive and reward conditioning task. We find that DA terminals in the ventral NAc medial shell (vNAcMed) are excited by unexpected aversive outcomes and to cues that predict them, whereas DA terminals in other NAc subregions are persistently depressed. Excitation to reward-predictive cues dominated in the NAc lateral shell and was largely absent in the vNAcMed. Moreover, we demonstrate that glutamatergic (VGLUT2-expressing) neurons in the lateral hypothalamus represent a key afferent input for providing information about aversive outcomes to vNAcMed-projecting DA neurons. Collectively, we reveal the distinct functional contributions of separate mesolimbic DA subsystems and their afferent pathways underlying motivated behaviors. VIDEO ABSTRACT.
Topics: Animals; Avoidance Learning; Dopaminergic Neurons; Limbic System; Male; Mesencephalon; Mice; Mice, Inbred C57BL; Mice, Transgenic; Nerve Net; Organ Culture Techniques; Photometry; Ventral Tegmental Area; Vesicular Glutamate Transport Protein 2
PubMed: 30503173
DOI: 10.1016/j.neuron.2018.11.005 -
Nature Methods Dec 2023Ventral midbrain dopaminergic neurons project to the striatum as well as the cortex and are involved in movement control and reward-related cognition. In Parkinson's...
Ventral midbrain dopaminergic neurons project to the striatum as well as the cortex and are involved in movement control and reward-related cognition. In Parkinson's disease, nigrostriatal midbrain dopaminergic neurons degenerate and cause typical Parkinson's disease motor-related impairments, while the dysfunction of mesocorticolimbic midbrain dopaminergic neurons is implicated in addiction and neuropsychiatric disorders. Study of the development and selective neurodegeneration of the human dopaminergic system, however, has been limited due to the lack of an appropriate model and access to human material. Here, we have developed a human in vitro model that recapitulates key aspects of dopaminergic innervation of the striatum and cortex. These spatially arranged ventral midbrain-striatum-cortical organoids (MISCOs) can be used to study dopaminergic neuron maturation, innervation and function with implications for cell therapy and addiction research. We detail protocols for growing ventral midbrain, striatal and cortical organoids and describe how they fuse in a linear manner when placed in custom embedding molds. We report the formation of functional long-range dopaminergic connections to striatal and cortical tissues in MISCOs, and show that injected, ventral midbrain-patterned progenitors can mature and innervate the tissue. Using these assembloids, we examine dopaminergic circuit perturbations and show that chronic cocaine treatment causes long-lasting morphological, functional and transcriptional changes that persist upon drug withdrawal. Thus, our method opens new avenues to investigate human dopaminergic cell transplantation and circuitry reconstruction as well as the effect of drugs on the human dopaminergic system.
Topics: Humans; Parkinson Disease; Mesencephalon; Dopamine; Dopaminergic Neurons; Corpus Striatum
PubMed: 38052989
DOI: 10.1038/s41592-023-02080-x -
Neuron Feb 2022Neurodegenerative disorders are characterized by a collapse in proteostasis, as shown by the accumulation of insoluble protein aggregates in the brain. Proteostasis...
Neurodegenerative disorders are characterized by a collapse in proteostasis, as shown by the accumulation of insoluble protein aggregates in the brain. Proteostasis involves a balance of protein synthesis, folding, trafficking, and degradation, but how aggregates perturb these pathways is unknown. Using Parkinson's disease (PD) patient midbrain cultures, we find that aggregated α-synuclein induces endoplasmic reticulum (ER) fragmentation and compromises ER protein folding capacity, leading to misfolding and aggregation of immature lysosomal β-glucocerebrosidase. Despite this, PD neurons fail to initiate the unfolded protein response, indicating perturbations in sensing or transducing protein misfolding signals in the ER. Small molecule enhancement of ER proteostasis machinery promotes β-glucocerebrosidase solubility, while simultaneous enhancement of trafficking improves ER morphology, lysosomal function, and reduces α-synuclein. Our studies suggest that aggregated α-synuclein perturbs the ability of neurons to respond to misfolded proteins in the ER, and that synergistic enhancement of multiple proteostasis branches may provide therapeutic benefit in PD.
Topics: Endoplasmic Reticulum; Humans; Mesencephalon; Neurons; Parkinson Disease; Protein Aggregation, Pathological; Protein Folding; Protein Transport; Proteostasis; alpha-Synuclein
PubMed: 34793693
DOI: 10.1016/j.neuron.2021.10.032 -
Proceedings of the National Academy of... Nov 2022The neurobiological understanding of obsessive-compulsive disorder (OCD) includes dysregulated frontostriatal circuitry and altered monoamine transmission. Repetitive...
The neurobiological understanding of obsessive-compulsive disorder (OCD) includes dysregulated frontostriatal circuitry and altered monoamine transmission. Repetitive stereotyped behavior (e.g., grooming), a featured symptom in OCD, has been proposed to be associated with perturbed dopamine (DA) signaling. However, the precise brain circuits participating in DA's control over this behavioral phenotype remain elusive. Here, we identified that DA neurons in substantia nigra pars compacta (SNc) orchestrate ventromedial striatum (VMS) microcircuits as well as lateral orbitofrontal cortex (lOFC) during self-grooming behavior. SNc-VMS and SNc-lOFC dopaminergic projections modulate grooming behaviors and striatal microcircuit function differentially. Specifically, the activity of the SNc-VMS pathway promotes grooming via D1 receptors, whereas the activity of the SNc-lOFC pathway suppresses grooming via D2 receptors. SNc DA neuron activity thus controls the OCD-like behaviors via both striatal and cortical projections as dual gating. These results support both pharmacological and brain-stimulation treatments for OCD.
Topics: Animals; Dopaminergic Neurons; Corpus Striatum; Dopamine; Obsessive-Compulsive Disorder; Mesencephalon; Substantia Nigra
PubMed: 36343236
DOI: 10.1073/pnas.2207545119 -
Neurobiology of Learning and Memory Dec 2020Novelty triggers an increase in orienting behavior that is critical to evaluate the potential salience of unknown events. As novelty becomes familiar upon repeated... (Review)
Review
Novelty triggers an increase in orienting behavior that is critical to evaluate the potential salience of unknown events. As novelty becomes familiar upon repeated encounters, this increase in response rapidly habituates as a form of behavioral adaptation underlying goal-directed behaviors. Many neurodevelopmental, psychiatric and neurodegenerative disorders are associated with abnormal responses to novelty and/or familiarity, although the neuronal circuits and cellular/molecular mechanisms underlying these natural behaviors in the healthy brain are largely unknown, as is the maladaptive processes that occur to induce impairment of novelty signaling in diseased brains. In rodents, the development of cutting-edge tools that allow for measurements of real time activity dynamics in selectively identified neuronal ensembles by gene expression signatures is beginning to provide advances in understanding the neural bases of the novelty response. Accumulating evidence indicate that midbrain circuits, the majority of which linked to dopamine transmission, promote exploratory assessments and guide approach/avoidance behaviors to different types of novelty via specific projection sites. The present review article focuses on midbrain circuit analysis relevant to novelty processing and habituation with familiarity.
Topics: Animals; Dopaminergic Neurons; Exploratory Behavior; Habituation, Psychophysiologic; Humans; Mesencephalon; Mice; Nerve Net; Raphe Nuclei; Rats; Recognition, Psychology
PubMed: 33053429
DOI: 10.1016/j.nlm.2020.107323 -
Nature Aug 2022Food and water are rewarding in part because they satisfy our internal needs. Dopaminergic neurons in the ventral tegmental area (VTA) are activated by gustatory...
Food and water are rewarding in part because they satisfy our internal needs. Dopaminergic neurons in the ventral tegmental area (VTA) are activated by gustatory rewards, but how animals learn to associate these oral cues with the delayed physiological effects of ingestion is unknown. Here we show that individual dopaminergic neurons in the VTA respond to detection of nutrients or water at specific stages of ingestion. A major subset of dopaminergic neurons tracks changes in systemic hydration that occur tens of minutes after thirsty mice drink water, whereas different dopaminergic neurons respond to nutrients in the gastrointestinal tract. We show that information about fluid balance is transmitted to the VTA by a hypothalamic pathway and then re-routed to downstream circuits that track the oral, gastrointestinal and post-absorptive stages of ingestion. To investigate the function of these signals, we used a paradigm in which a fluid's oral and post-absorptive effects can be independently manipulated and temporally separated. We show that mice rapidly learn to prefer one fluid over another based solely on its rehydrating ability and that this post-ingestive learning is prevented if dopaminergic neurons in the VTA are selectively silenced after consumption. These findings reveal that the midbrain dopamine system contains subsystems that track different modalities and stages of ingestion, on timescales from seconds to tens of minutes, and that this information is used to drive learning about the consequences of ingestion.
Topics: Animals; Cues; Digestion; Dopamine; Dopaminergic Neurons; Eating; Gastrointestinal Tract; Hypothalamus; Mesencephalon; Mice; Neural Pathways; Nutrients; Organism Hydration Status; Reward; Time Factors; Ventral Tegmental Area; Water; Water-Electrolyte Balance
PubMed: 35831501
DOI: 10.1038/s41586-022-04954-0 -
Nature Dec 2023The function of the mammalian brain relies upon the specification and spatial positioning of diversely specialized cell types. Yet, the molecular identities of the cell...
The function of the mammalian brain relies upon the specification and spatial positioning of diversely specialized cell types. Yet, the molecular identities of the cell types and their positions within individual anatomical structures remain incompletely known. To construct a comprehensive atlas of cell types in each brain structure, we paired high-throughput single-nucleus RNA sequencing with Slide-seq-a recently developed spatial transcriptomics method with near-cellular resolution-across the entire mouse brain. Integration of these datasets revealed the cell type composition of each neuroanatomical structure. Cell type diversity was found to be remarkably high in the midbrain, hindbrain and hypothalamus, with most clusters requiring a combination of at least three discrete gene expression markers to uniquely define them. Using these data, we developed a framework for genetically accessing each cell type, comprehensively characterized neuropeptide and neurotransmitter signalling, elucidated region-specific specializations in activity-regulated gene expression and ascertained the heritability enrichment of neurological and psychiatric phenotypes. These data, available as an online resource ( www.BrainCellData.org ), should find diverse applications across neuroscience, including the construction of new genetic tools and the prioritization of specific cell types and circuits in the study of brain diseases.
Topics: Animals; Mice; Brain; Gene Expression Profiling; High-Throughput Nucleotide Sequencing; Hypothalamus; Mesencephalon; Neuropeptides; Neurotransmitter Agents; Phenotype; Rhombencephalon; Single-Cell Gene Expression Analysis; Transcriptome
PubMed: 38092915
DOI: 10.1038/s41586-023-06818-7 -
Neuron Jan 2020Many brain areas modulate their activity during vibrotactile tasks. The activity from these areas may code the stimulus parameters, stimulus perception, or perceptual... (Review)
Review
Many brain areas modulate their activity during vibrotactile tasks. The activity from these areas may code the stimulus parameters, stimulus perception, or perceptual reports. Here, we discuss findings obtained in behaving monkeys aimed to understand these processes. In brief, neurons from the somatosensory thalamus and primary somatosensory cortex (S1) only code the stimulus parameters during the stimulation periods. In contrast, areas downstream of S1 code the stimulus parameters during not only the task components but also perception. Surprisingly, the midbrain dopamine system is an actor not considered before in perception. We discuss the evidence that it codes the subjective magnitude of a sensory percept. The findings reviewed here may help us to understand where and how sensation transforms into perception in the brain.
Topics: Animals; Dopaminergic Neurons; Mesencephalon; Somatosensory Cortex; Thalamus; Touch; Touch Perception
PubMed: 31917952
DOI: 10.1016/j.neuron.2019.11.033