scholarly journals Quantitative synapse analysis for cell-type specific connectomics

2018 ◽  
Author(s):  
Dika A. Kuljis ◽  
Khaled Zemoura ◽  
Cheryl A. Telmer ◽  
Jiseok Lee ◽  
Eunsol Park ◽  
...  
Keyword(s):  
Large Scale ◽  
Neural Circuit ◽  
Apical Dendrite ◽  
Automated Detection ◽  
Cell Type ◽  
Disease States ◽  
Specific Localization ◽  
Cell Type Specific ◽  
Dendritic Branches ◽  
Circuit Function

AbstractAnatomical methods for determining cell-type specific connectivity are essential to inspire and constrain our understanding of neural circuit function. We developed new genetically-encoded reagents for fluorescence-synapse labeling and connectivity analysis in brain tissue, using a fluorogen-activating protein (FAP)-or YFP-coupled, postsynaptically-localized neuroligin-1 targeting sequence (FAP/YFPpost). Sparse viral expression of FAP/YFPpost with the cell-filling, red fluorophore dTomato (dTom) enabled high-throughput, compartment-specific localization of synapses across diverse neuron types in mouse somatosensory cortex. High-resolution confocal image stacks of virally-transduced neurons were used for 3D reconstructions of postsynaptic cells and automated detection of synaptic puncta. We took advantage of the bright, far-red emission of FAPpost puncta for multichannel fluorescence alignment of dendrites, synapses, and presynaptic neurites to assess subtype-specific inhibitory connectivity onto L2 neocortical pyramidal (Pyr) neurons. Quantitative and compartment-specific comparisons show that PV inputs are the dominant source of inhibition at both the soma and across all dendritic branches examined and were particularly concentrated at the primary apical dendrite, a previously unrecognized compartment of L2 Pyr neurons. Our fluorescence-based synapse labeling reagents will facilitate large-scale and cell-type specific quantitation of changes in synaptic connectivity across development, learning, and disease states.

scholarly journals Semi-automated annotation of cell type-specific protein expression patterns in human testis based on immunohistochemistry

2020 ◽  
Author(s):  
Biraja Ghoshal ◽  
Allan Tucker ◽  
Feria Hikmet Norradin ◽  
Cecilia Lindskog
Keyword(s):  
Protein Expression ◽  
Large Scale ◽  
Expression Patterns ◽  
Cell Types ◽  
Specific Protein ◽  
Human Testis ◽  
Cell Type ◽  
Bayesian Neural Network ◽  
Specific Localization ◽  
Cell Type Specific

Abstract Immunohistochemistry (IHC) provides the basis for cell type-specific localization of protein expression patterns in human tissues. Manual annotation of complex IHC images is however expensive and may lead to errors or inter-observer variability. Artificial Intelligence holds much promise for efficient and accurate pattern recognition, but confidence in prediction needs to be addressed. To present a reliable model for annotation of IHC images, we developed a semi-automated framework for multi-label classification of 7,848 human testis samples stained with IHC, and manually annotated in situ protein expression in eight different cell types. The dataset was used as a basis for training and testing a proposed Hybrid Bayesian Neural Network. By combining the deep learning model with a novel uncertainty metric, the average diagnostic performance improved from 86.9% to 96.3%. The streamlined workflow has important implications for accurate large-scale efforts mapping the human cell type-specific proteome in health and disease.

scholarly journals Shisa6 mediates cell-type specific regulation of depression in the nucleus accumbens

2021 ◽  
Author(s):  
Hee-Dae Kim ◽  
Jing Wei ◽  
Tanessa Call ◽  
Nicole Teru Quintus ◽  
Alexander J. Summers ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Molecular Mechanisms ◽  
Cell Types ◽  
Current Treatment ◽  
Specific Cell ◽  
Excitatory Synapses ◽  
Cell Type ◽  
Cell Type Specific ◽  
Specific Regulation ◽  
Circuit Function

AbstractDepression is the leading cause of disability and produces enormous health and economic burdens. Current treatment approaches for depression are largely ineffective and leave more than 50% of patients symptomatic, mainly because of non-selective and broad action of antidepressants. Thus, there is an urgent need to design and develop novel therapeutics to treat depression. Given the heterogeneity and complexity of the brain, identification of molecular mechanisms within specific cell-types responsible for producing depression-like behaviors will advance development of therapies. In the reward circuitry, the nucleus accumbens (NAc) is a key brain region of depression pathophysiology, possibly based on differential activity of D1- or D2- medium spiny neurons (MSNs). Here we report a circuit- and cell-type specific molecular target for depression, Shisa6, recently defined as an AMPAR component, which is increased only in D1-MSNs in the NAc of susceptible mice. Using the Ribotag approach, we dissected the transcriptional profile of D1- and D2-MSNs by RNA sequencing following a mouse model of depression, chronic social defeat stress (CSDS). Bioinformatic analyses identified cell-type specific genes that may contribute to the pathogenesis of depression, including Shisa6. We found selective optogenetic activation of the ventral tegmental area (VTA) to NAc circuit increases Shisa6 expression in D1-MSNs. Shisa6 is specifically located in excitatory synapses of D1-MSNs and increases excitability of neurons, which promotes anxiety- and depression-like behaviors in mice. Cell-type and circuit-specific action of Shisa6, which directly modulates excitatory synapses that convey aversive information, identifies the protein as a potential rapid-antidepressant target for aberrant circuit function in depression.

scholarly journals Cell-type-specific role for nucleus accumbens neuroligin-2 in depression and stress susceptibility

2018 ◽  
Vol 115 (5) ◽  
pp. 1111-1116 ◽  
Author(s):  
Mitra Heshmati ◽  
Hossein Aleyasin ◽  
Caroline Menard ◽  
Daniel J. Christoffel ◽  
Meghan E. Flanigan ◽  
...  
Keyword(s):  
Nucleus Accumbens ◽  
Cell Type ◽  
Dopamine D2 ◽  
Disease States ◽  
Specific Effects ◽  
Chronic Social Defeat Stress ◽  
Cell Type Specific ◽  
Stress Susceptibility ◽  
Cell Adhesion Proteins

Behavioral coping strategies are critical for active resilience to stress and depression; here we describe a role for neuroligin-2 (NLGN-2) in the nucleus accumbens (NAc). Neuroligins (NLGN) are a family of neuronal postsynaptic cell adhesion proteins that are constituents of the excitatory and inhibitory synapse. Importantly, NLGN-3 and NLGN-4 mutations are strongly implicated as candidates underlying the development of neuropsychiatric disorders with social disturbances such as autism, but the role of NLGN-2 in neuropsychiatric disease states is unclear. Here we show a reduction in NLGN-2 gene expression in the NAc of patients with major depressive disorder. Chronic social defeat stress in mice also decreases NLGN-2 selectively in dopamine D1-positive cells, but not dopamine D2-positive cells, within the NAc of stress-susceptible mice. Functional NLGN-2 knockdown produces bidirectional, cell-type-specific effects: knockdown in dopamine D1-positive cells promotes subordination and stress susceptibility, whereas knockdown in dopamine D2-positive cells mediates active defensive behavior. These findings establish a behavioral role for NAc NLGN-2 in stress and depression; provide a basis for targeted, cell-type specific therapy; and highlight the role of active behavioral coping mechanisms in stress susceptibility.

scholarly journals Maintenance of cell type-specific connectivity and circuit function requires Tao kinase

2019 ◽  
Vol 10 (1) ◽  
Author(s):  
Federico Marcello Tenedini ◽  
Maria Sáez González ◽  
Chun Hu ◽  
Lisa Hedegaard Pedersen ◽  
Mabel Matamala Petruzzi ◽  
...  
Keyword(s):  
Cell Type ◽  
Cell Type Specific ◽  
Circuit Function

scholarly journals ASCOT identifies key regulators of neuronal subtype-specific splicing

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Jonathan P. Ling ◽  
Christopher Wilks ◽  
Rone Charles ◽  
Patrick J. Leavey ◽  
Devlina Ghosh ◽  
...  
Keyword(s):  
Rna Splicing ◽  
Large Scale ◽  
Splice Variants ◽  
Next Generation Sequencing Data ◽  
Data Sets ◽  
Cell Type ◽  
Sequencing Data ◽  
Large Scale Analysis ◽  
Cell Type Specific ◽  
Public Archives

AbstractPublic archives of next-generation sequencing data are growing exponentially, but the difficulty of marshaling this data has led to its underutilization by scientists. Here, we present ASCOT, a resource that uses annotation-free methods to rapidly analyze and visualize splice variants across tens of thousands of bulk and single-cell data sets in the public archive. To demonstrate the utility of ASCOT, we identify novel cell type-specific alternative exons across the nervous system and leverage ENCODE and GTEx data sets to study the unique splicing of photoreceptors. We find that PTBP1 knockdown and MSI1 and PCBP2 overexpression are sufficient to activate many photoreceptor-specific exons in HepG2 liver cancer cells. This work demonstrates how large-scale analysis of public RNA-Seq data sets can yield key insights into cell type-specific control of RNA splicing and underscores the importance of considering both annotated and unannotated splicing events.

scholarly journals State-dependent control of cortical processing speed via gain modulation

2020 ◽  
Author(s):  
David Wyrick ◽  
Luca Mazzucato
Keyword(s):  
Information Processing ◽  
Processing Speed ◽  
Visual Processing ◽  
Large Scale ◽  
Internal State ◽  
Gain Modulation ◽  
Cell Type ◽  
Information Processing Speed ◽  
Afferent Projections ◽  
Cell Type Specific

AbstractTo thrive in dynamic environments, animals can generate flexible behavior and rapidly adapt responses to a changing context and internal state. Examples of behavioral flexibility include faster stimulus responses when attentive and slower responses when distracted. Contextual modulations may occur early in the cortical hierarchy and may be implemented via afferent projections from top-down pathways or neuromodulation onto sensory cortex. However, the computational mechanisms mediating the effects of such projections are not known. Here, we investigate the effects of afferent projections on the information processing speed of cortical circuits. Using a biologically plausible model based on recurrent networks of excitatory and inhibitory neurons arranged in cluster, we classify the effects of cell-type specific perturbations on the circuit’s stimulus-processing capability. We found that perturbations differentially controlled processing speed, leading to counter-intuitive effects such as improved performance with increased input variance. Our theory explains the effects of all perturbations in terms of gain modulation, which controls the timescale of the circuit dynamics. We tested our model using large-scale electrophysiological recordings from the visual hierarchy in freely running mice, where a decrease in single-cell gain during locomotion explained the observed acceleration of visual processing speed. Our results establish a novel theory of cell-type specific perturbations linking connectivity, dynamics, and information processing via gain modulations.

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