Cell-type specificity of neuronal excitability and morphology in the central amygdala

ABSTRACTCentral amygdala (CeA) neurons expressing protein kinase C delta (PKCδ+) or Somatostatin (Som+) differentially modulate diverse behaviors. The underlying features supporting cell-type-specific function in the CeA, however, remain unknown. Using whole-cell patch-clamp electrophysiology in acute mouse brain slices and biocytin-based neuronal reconstructions, we demonstrate that neuronal morphology and relative excitability are two distinguishing features between Som+ and PKCδ+ CeLC neurons. Som+ neurons, for example, are more excitable, compact and with more complex dendritic arborizations than PKCδ+ neurons. Cell size, intrinsic membrane properties, and anatomical localization were further shown to correlate with cell-type-specific differences in excitability. Lastly, in the context of neuropathic pain, we show a shift in the excitability equilibrium between PKCδ+ and Som+ neurons, suggesting that imbalances in the relative output of these cells underlie maladaptive changes in behaviors. Together, our results identify fundamentally important distinguishing features of PKCδ+ and Som+ cells that support cell-type-specific function in the CeA.

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Cell-Type Specificity of Neuronal Excitability and Morphology in the Central Amygdala

eNeuro ◽

10.1523/eneuro.0402-20.2020 ◽

2020 ◽

pp. ENEURO.0402-20.2020

Author(s):

Anisha P. Adke ◽

Aleisha Khan ◽

Hye-Sook Ahn ◽

Jordan J. Becker ◽

Torri D. Wilson ◽

...

Keyword(s):

Neuronal Excitability ◽

Cell Type ◽

Central Amygdala ◽

Cell Type Specificity

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Parallel evolution of a splicing program controlling neuronal excitability in flies and mammals

10.1101/2021.02.24.432780 ◽

2021 ◽

Author(s):

Antonio Torres-Méndez ◽

Sinziana Pop ◽

Sophie Bonnal ◽

Isabel Almudi ◽

Alida Avola ◽

...

Keyword(s):

Alternative Splicing ◽

Neuronal Excitability ◽

Parallel Evolution ◽

Cell Type ◽

Cell Type Specificity ◽

Genome Wide ◽

Neuronal Imaging ◽

Cell Type Specific ◽

Neurological Alterations ◽

Animal Phylogeny

SummaryNeurons draw on alternative splicing for their increased transcriptomic complexity throughout animal phylogeny. To delve into the mechanisms controlling the assembly and evolution of this regulatory layer, we characterized the neuronal microexon program in Drosophila and compared it with that of mammals. We found that in Drosophila, this splicing program is restricted to neurons by the post-transcriptional processing of the enhancer of microexons (eMIC) domain in Srrm234 by Elav and Fne. eMIC deficiency or misexpression leads to widespread neurological alterations largely emerging from impaired neuronal activity, as revealed by a combination of neuronal imaging experiments and cell-type-specific rescues. These defects are associated with the genome-wide skipping of short neural exons, which are strongly enriched in ion channels. Remarkably, we found no overlap of eMIC-regulated exons between flies and mice, illustrating how ancient post-transcriptional programs can evolve independently in different phyla to impact distinct cellular modules while maintaining cell-type specificity.

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A scalable platform for the development of cell-type-specific viral drivers

eLife ◽

10.7554/elife.48089 ◽

2019 ◽

Vol 8 ◽

Cited By ~ 12

Author(s):

Sinisa Hrvatin ◽

Christopher P Tzeng ◽

M Aurel Nagy ◽

Hume Stroud ◽

Charalampia Koutsioumpa ◽

...

Keyword(s):

Gene Expression ◽

Heterologous Gene Expression ◽

High Specificity ◽

Cell Types ◽

Regulatory Elements ◽

Cell Type ◽

Cell Type Specificity ◽

Cell Type Specific ◽

The Many ◽

Dna Regulatory Elements

Enhancers are the primary DNA regulatory elements that confer cell type specificity of gene expression. Recent studies characterizing individual enhancers have revealed their potential to direct heterologous gene expression in a highly cell-type-specific manner. However, it has not yet been possible to systematically identify and test the function of enhancers for each of the many cell types in an organism. We have developed PESCA, a scalable and generalizable method that leverages ATAC- and single-cell RNA-sequencing protocols, to characterize cell-type-specific enhancers that should enable genetic access and perturbation of gene function across mammalian cell types. Focusing on the highly heterogeneous mammalian cerebral cortex, we apply PESCA to find enhancers and generate viral reagents capable of accessing and manipulating a subset of somatostatin-expressing cortical interneurons with high specificity. This study demonstrates the utility of this platform for developing new cell-type-specific viral reagents, with significant implications for both basic and translational research.

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Calling differential DNA methylation at cell-type resolution: addressing misconceptions and best practices

10.1101/2021.02.14.431168 ◽

2021 ◽

Author(s):

Elior Rahmani ◽

Brandon Jew ◽

Regev Schweiger ◽

Brooke Rhead ◽

Lindsey A. Criswell ◽

...

Keyword(s):

Dna Methylation ◽

Best Practices ◽

Regression Model ◽

Association Studies ◽

Composition Analysis ◽

Cell Type ◽

Cell Type Specificity ◽

Interaction Terms ◽

Mathematical Explanations ◽

Cell Type Specific

AbstractWe benchmarked two approaches for the detection of cell-type-specific differential DNA methylation: Tensor Composition Analysis (TCA) and a regression model with interaction terms (CellDMC). Our experiments alongside rigorous mathematical explanations show that TCA is superior over CellDMC, thus resolving recent criticisms suggested by Jing et al. Following misconceptions by Jing and colleagues with modelling cell-type-specificity and the application of TCA, we further discuss best practices for performing association studies at cell-type resolution. The scripts for reproducing all of our results and figures are publicly available at github.com/cozygene/CellTypeSpecificMethylationAnalysis.

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Genetic engineering for in vivo optical interrogation of neuronal responses to cell type-specific silencing

10.1101/2021.01.13.426508 ◽

2021 ◽

Author(s):

Firat Terzi ◽

Johannes Knabbe ◽

Sidney B. Cambridge

Keyword(s):

High Resolution ◽

Genetic Engineering ◽

Transgene Expression ◽

Neuronal Morphology ◽

Dependent Manner ◽

Cell Type ◽

Fluorescent Marker ◽

Genetic Perturbations ◽

Cell Type Specific

SummaryGenetic engineering of quintuple transgenic brain tissue was used to establish a low background, Cre-dependent version of the inducible Tet-On system for fast, cell type-specific transgene expression in vivo. Co-expression of a constitutive, Cre-dependent fluorescent marker selectively allowed single cell analyses before and after inducible, tet-dependent transgene expression. Here, we used this method for acute, high-resolution manipulation of neuronal activity in the living brain. Single induction of the potassium channel Kir2.1 produced cell type-specific silencing within hours that lasted for at least three days. Longitudinal in vivo imaging of spontaneous calcium transients and neuronal morphology demonstrated that prolonged silencing did not alter spine densities or synaptic input strength. Furthermore, selective induction of Kir2.1 in parvalbumin interneurons increased the activity of surrounding neurons in a distance-dependent manner. This high-resolution, inducible interference and interval imaging of individual cells (high I5, ‘HighFive’) method thus allows visualizing temporally precise, genetic perturbations of defined cells.

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Cell type-specific effects of isoflurane on two distinct afferent inputs to cortical layer 1

10.1101/2020.05.18.102913 ◽

2020 ◽

Author(s):

Caitlin A. Murphy ◽

Matthew I. Banks

Keyword(s):

Ex Vivo ◽

Brain Slices ◽

Pyramidal Cells ◽

Cellular Level ◽

Cortical Layer ◽

Cell Type ◽

Specific Effects ◽

Primary Mouse ◽

Cell Type Specific ◽

Synaptic Responses

ABSTRACTBackgroundWhile their behavioral effects are well-characterized, the mechanisms by which anaesthetics induce loss of consciousness are largely unknown. Anaesthetics may disrupt integration and propagation of information in corticothalamic networks. Recent studies have shown that isoflurane diminishes synaptic responses of thalamocortical (TC) and corticocortical (CC) afferents in a pathway-specific manner. However, whether the synaptic effects of isoflurane observed in extracellular recordings persist at the cellular level has yet to be explored.MethodsHere, we activate TC and CC layer 1 inputs in non-primary mouse neocortex in ex vivo brain slices and explore the degree to which isoflurane modulates synaptic responses in pyramidal cells and in two inhibitory cell populations, somatostatin-positive (SOM+) and parvalbumin-positive (PV+) interneurons.ResultsWe show that the effects of isoflurane on synaptic responses and intrinsic properties of these cells varies among cell type and by cortical layer. Layer 1 inputs to L4 pyramidal cells were suppressed by isoflurane at both TC and CC synapses, while those to L2/3 pyramidal cells and PV+ interneurons were not. TC inputs to SOM+ cells were rarely observed at all, while CC inputs to SOM+ interneurons were robustly suppressed by isoflurane.ConclusionsThese results suggest a mechanism by which isoflurane disrupts integration and propagation of thalamocortical and intracortical signals.

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Cell-type-specific function of c-Jun N-terminal kinases (JNKs) determines the cholestasis activity in murine model

10.1055/s-0041-1733628 ◽

2021 ◽

Author(s):

MR Mohamed ◽

G Zhao ◽

YA Nevzorova ◽

J Haybaeck ◽

MV Boekschoten ◽

...

Keyword(s):

Murine Model ◽

Specific Function ◽

Cell Type ◽

Cell Type Specific

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Distinct Electrophysiological Properties in Subtypes of Nonspiking Olfactory Local Interneurons Correlate With Their Cell Type–Specific Ca2+ Current Profiles

Journal of Neurophysiology ◽

10.1152/jn.00627.2009 ◽

2009 ◽

Vol 102 (5) ◽

pp. 2834-2845 ◽

Cited By ~ 24

Author(s):

Andreas Husch ◽

Moritz Paehler ◽

Debora Fusca ◽

Lars Paeger ◽

Peter Kloppenburg

Keyword(s):

Periplaneta Americana ◽

Membrane Properties ◽

Type Ii ◽

Diverse Population ◽

Cell Type ◽

Cellular Mechanisms ◽

Electrophysiological Properties ◽

Local Interneurons ◽

Cell Type Specific ◽

Process Structure

A diverse population of local interneurons (LNs) helps to process, structure, and spatially represent olfactory information in the insect antennal lobe. In Periplaneta americana, we identified two subtypes of nonspiking local interneurons (type II LNs) by their distinct morphological and intrinsic electrophysiological properties. As an important step toward a better understanding of the cellular mechanisms that mediate odor information processing, we present a detailed analysis of their distinct voltage-activated Ca2+ currents, which clearly correlated with their distinct intrinsic electrophysiological properties. Both type II LNs did not posses voltage-activated Na+ currents and apparently innervated all glomeruli including the macroglomerulus. Type IIa LNs had significant longer and thicker low-order neurites and innervated each glomerulus entirely and homogeneously, whereas type IIb LNs innervated only parts of each glomerulus. All type II LNs were broadly tuned and responded to odorants of many chemical classes with graded changes in the membrane potential. Type IIa LNs responded with odor-specific elaborate patterns of excitation that could also include “spikelets” riding on the depolarizations and periods of inhibition. In contrast, type IIb LNs responded mostly with sustained, relatively smooth depolarizations. Consistent with the strong active membrane properties of type IIa LNs versus type IIb LNs, the voltage-activated Ca2+ current of type IIa LNs activated at more hyperpolarized membrane potentials and had a larger transient component.

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