scholarly journals Transcriptional Diversity of Medium Spiny Neurons in the Primate Striatum

2020 ◽  
Author(s):  
Jing He ◽  
Michael Kleyman ◽  
Jianjiao Chen ◽  
Aydin Alikaya ◽  
Kathryn M. Rothenhoefer ◽  
...  

AbstractThe striatum is the neural interface between dopamine reward signals and cortico-basal ganglia circuits responsible for value assignments, decisions, and actions. Medium spiny neurons (MSNs) make up the vast majority of striatal neurons and are traditionally classified as two distinct types: direct- and indirect-pathway MSNs. The direct- and indirect-pathway model has been useful for understanding some aspects of striatal functions, but it accounts for neither the anatomical heterogeneity, nor the functional diversity of the striatum. Here, we use single nucleus RNA-sequencing and Fluorescent In-Situ Hybridization to explore MSN diversity in the Rhesus macaque striatum. We identified MSN subtypes that correspond to the major subdivisions of the striatum. These include dorsal striatum subtypes associated with striosome and matrix compartments, as well as ventral striatum subtypes associated with the shell of the nucleus accumbens. We also describe a cell type that is anatomically restricted to “Neurochemically Unique Domains in the Accumbens and Putamen (NUDAPs)”. Together, these results help to advance nonhuman primate studies into the genomics era. The identified cell types provide a comprehensive blueprint for investigating cell type-specific information processing, and the differentially expressed genes lay a foundation for achieving cell type-specific transgenesis in the primate striatum.

Function ◽  
2021 ◽  
Author(s):  
Tanya Sippy ◽  
Corryn Chaimowitz ◽  
Sylvain Crochet ◽  
Carl C H Petersen

Abstract The striatum integrates sensorimotor and motivational signals, likely playing a key role in reward-based learning of goal-directed behavior. However, cell type-specific mechanisms underlying reinforcement learning remain to be precisely determined. Here, we investigated changes in membrane potential dynamics of dorsolateral striatal neurons comparing naïve mice and expert mice trained to lick a reward spout in response to whisker deflection. We recorded from three distinct cell types: i) direct pathway striatonigral neurons, which express type 1 dopamine receptors; ii) indirect pathway striatopallidal neurons, which express type 2 dopamine receptors; and iii) tonically active, putative cholinergic, striatal neurons. Task learning was accompanied by cell type-specific changes in the membrane potential dynamics evoked by the whisker deflection and licking in successfully-performed trials. Both striatonigral and striatopallidal types of striatal projection neurons showed enhanced task-related depolarization across learning. Striatonigral neurons showed a prominent increase in a short latency sensory-evoked depolarization in expert compared to naïve mice. In contrast, the putative cholinergic striatal neurons developed a hyperpolarizing response across learning, driving a pause in their firing. Our results reveal cell type-specific changes in striatal membrane potential dynamics across the learning of a simple goal-directed sensorimotor transformation, helpful for furthering the understanding of the various potential roles of different basal ganglia circuits.


2021 ◽  
Vol 12 (1) ◽  
Author(s):  
V. Dumrongprechachan ◽  
R. B. Salisbury ◽  
G. Soto ◽  
M. Kumar ◽  
M. L. MacDonald ◽  
...  

AbstractThe vertebrate brain consists of diverse neuronal types, classified by distinct anatomy and function, along with divergent transcriptomes and proteomes. Defining the cell-type specific neuroproteomes is important for understanding the development and functional organization of neural circuits. This task remains challenging in complex tissue, due to suboptimal protein isolation techniques that often result in loss of cell-type specific information and incomplete capture of subcellular compartments. Here, we develop a genetically targeted proximity labeling approach to identify cell-type specific subcellular proteomes in the mouse brain, confirmed by imaging, electron microscopy, and mass spectrometry. We virally express subcellular-localized APEX2 to map the proteome of direct and indirect pathway spiny projection neurons in the striatum. The workflow provides sufficient depth to uncover changes in the proteome of striatal neurons following chemogenetic activation of Gαq-coupled signaling cascades. This method enables flexible, cell-type specific quantitative profiling of subcellular proteome snapshots in the mouse brain.


2019 ◽  
Vol 9 (1) ◽  
Author(s):  
Hope Kronman ◽  
Felix Richter ◽  
Benoit Labonté ◽  
Ramesh Chandra ◽  
Shan Zhao ◽  
...  

2021 ◽  
Author(s):  
Marija Fjodorova ◽  
Zoe Noakes ◽  
Daniel C. De La Fuente ◽  
Adam C. Errington ◽  
Meng Li

SummaryBackgroundStriatal medium spiny neurons (MSNs) are preferentially lost in Huntington’s disease. Genomic studies also implicate a direct role for MSNs in schizophrenia, a psychiatric disorder known to involve cortical neuron dysfunction. It remains unknown whether the two diseases share similar MSN pathogenesis or if neuronal deficits can be attributed to cell type-dependent biological pathways. Transcription factor BCL11B, which is expressed by all MSNs and deep layer cortical neurons, was recently proposed to drive selective neurodegeneration in Huntington’s disease and identified as a candidate risk gene in schizophrenia.MethodsUsing human stem cell-derived neurons lacking BCL11B as a model, we investigated cellular pathology in MSNs and cortical neurons in the context of these disorders. Integrative analyses between differentially expressed transcripts and published GWAS datasets identified cell type-specific disease-related phenotypes.ResultsWe uncover a role for BCL11B in calcium homeostasis in both neuronal types, while deficits in mitochondrial function and protein kinase A (PKA)-dependent calcium transients are detected only in MSNs. Moreover, BCL11B-deficient MSNs display abnormal responses to glutamate and fail to integrate dopaminergic and glutamatergic stimulation, a key feature of striatal neurons in vivo. Gene enrichment analysis reveals overrepresentation of disorder risk genes among BCL11B-regulated pathways, primarily relating to cAMP-PKA-calcium signaling axis and synaptic signaling.ConclusionsOur study indicates that Huntington’s disease and schizophrenia are likely to share neuronal pathogenesis where dysregulation of intracellular calcium levels is found in both striatal and cortical neurons. In contrast, reduction in PKA signaling and abnormal dopamine/glutamate receptor signaling is largely specific to MSNs.


2017 ◽  
Vol 3 (1) ◽  
pp. 46 ◽  
Author(s):  
Elham Azizi ◽  
Sandhya Prabhakaran ◽  
Ambrose Carr ◽  
Dana Pe'er

Single-cell RNA-seq gives access to gene expression measurements for thousands of cells, allowing discovery and characterization of cell types. However, the data is noise-prone due to experimental errors and cell type-specific biases. Current computational approaches for analyzing single-cell data involve a global normalization step which introduces incorrect biases and spurious noise and does not resolve missing data (dropouts). This can lead to misleading conclusions in downstream analyses. Moreover, a single normalization removes important cell type-specific information. We propose a data-driven model, BISCUIT, that iteratively normalizes and clusters cells, thereby separating noise from interesting biological signals. BISCUIT is a Bayesian probabilistic model that learns cell-specific parameters to intelligently drive normalization. This approach displays superior performance to global normalization followed by clustering in both synthetic and real single-cell data compared with previous methods, and allows easy interpretation and recovery of the underlying structure and cell types.


2000 ◽  
Vol 84 (5) ◽  
pp. 2225-2236 ◽  
Author(s):  
Robert C. Foehring ◽  
Paul G. Mermelstein ◽  
Wen-Jie Song ◽  
Sasha Ulrich ◽  
D. James Surmeier

Whole cell recordings from acutely dissociated neocortical pyramidal neurons and striatal medium spiny neurons exhibited a calcium-channel current resistant to known blockers of L-, N-, and P/Q-type Ca2+ channels. These R-type currents were characterized as high-voltage–activated (HVA) by their rapid deactivation kinetics, half-activation and half-inactivation voltages, and sensitivity to depolarized holding potentials. In both cell types, the R-type current activated at potentials relatively negative to other HVA currents in the same cell type and inactivated rapidly compared with the other HVA currents. The main difference between cell types was that R-type currents in neocortical pyramidal neurons inactivated at more negative potentials than R-type currents in medium spiny neurons. Ni2+ sensitivity was not diagnostic for R-type currents in either cell type. Single-cell RT-PCR revealed that both cell types expressed the α1E mRNA, consistent with this subunit being associated with the R-type current.


2017 ◽  
Vol 23 (32) ◽  
pp. 4716-4725 ◽  
Author(s):  
Trevor Clancy ◽  
Ruth Dannenfelser ◽  
Olga Troyanskaya ◽  
Karl Johan Malmberg ◽  
Eivind Hovig ◽  
...  

In the microenvironment of a malignancy, tumor cells do not exist in isolation, but rather in a diverse ecosystem consisting not only of heterogeneous tumor-cell clones, but also normal cell types such as fibroblasts, vasculature, and an extensive pool of immune cells at numerous possible stages of activation and differentiation. This results in a complex interplay of diverse cellular signaling systems, where the immune cell component is now established to influence cancer progression and therapeutic response. It is experimentally difficult and laborious to comprehensively and systematically profile these distinct cell types from heterogeneous tumor samples in order to capitalize on potential therapeutic and biomarker discoveries. One emerging solution to address this challenge is to computationally extract cell-type specific information directly from bulk tumors. Such in silico approaches are advantageous because they can capture both the cell-type specific profiles and the tissue systems level of cell-cell interactions. Accurately and comprehensively predicting these patterns in tumors is an important challenge to overcome, not least given the success of immunotherapeutic drug treatment of several human cancers. This is especially challenging for subsets of closely related immune cell phenotypes with relatively small gene expression differences, which have critical functional distinctions. Here, we outline the existing and emerging novel bioinformatics strategies that can be used to profile the tumor immune landscape.


2021 ◽  
Vol 22 (1) ◽  
Author(s):  
Kai Kang ◽  
Caizhi Huang ◽  
Yuanyuan Li ◽  
David M. Umbach ◽  
Leping Li

Abstract Background Biological tissues consist of heterogenous populations of cells. Because gene expression patterns from bulk tissue samples reflect the contributions from all cells in the tissue, understanding the contribution of individual cell types to the overall gene expression in the tissue is fundamentally important. We recently developed a computational method, CDSeq, that can simultaneously estimate both sample-specific cell-type proportions and cell-type-specific gene expression profiles using only bulk RNA-Seq counts from multiple samples. Here we present an R implementation of CDSeq (CDSeqR) with significant performance improvement over the original implementation in MATLAB and an added new function to aid cell type annotation. The R package would be of interest for the broader R community. Result We developed a novel strategy to substantially improve computational efficiency in both speed and memory usage. In addition, we designed and implemented a new function for annotating the CDSeq estimated cell types using single-cell RNA sequencing (scRNA-seq) data. This function allows users to readily interpret and visualize the CDSeq estimated cell types. In addition, this new function further allows the users to annotate CDSeq-estimated cell types using marker genes. We carried out additional validations of the CDSeqR software using synthetic, real cell mixtures, and real bulk RNA-seq data from the Cancer Genome Atlas (TCGA) and the Genotype-Tissue Expression (GTEx) project. Conclusions The existing bulk RNA-seq repositories, such as TCGA and GTEx, provide enormous resources for better understanding changes in transcriptomics and human diseases. They are also potentially useful for studying cell–cell interactions in the tissue microenvironment. Bulk level analyses neglect tissue heterogeneity, however, and hinder investigation of a cell-type-specific expression. The CDSeqR package may aid in silico dissection of bulk expression data, enabling researchers to recover cell-type-specific information.


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