scholarly journals Voltage imaging using transgenic mouse lines expressing the GEVI ArcLight in two olfactory cell types

2020 ◽  
Author(s):  
Jelena Platisa ◽  
Hongkui Zeng ◽  
Linda Madisen ◽  
Lawrence B. Cohen ◽  
Vincent A Pieribone ◽  
...  
Keyword(s):  
Transgenic Mouse ◽  
Granule Cells ◽  
Signal To Noise Ratio ◽  
Expression System ◽  
Cell Types ◽  
Mammalian Brain ◽  
Voltage Imaging ◽  
Genetic Tool ◽  
Mouse Lines

AbstractGenetically encoded voltage indicators (GEVIs) allow for cell-specific optical recordings of membrane potential changes in defined cell populations. One tool that would further their use in the in vivo mammalian brain is transgenic reporter animals that facilitate precise and repeatable targeting with high expression levels. The present literature on the development and use of transgenic mouse lines as vehicles for GEVI expression is limited. Here we report the first in vivo experiments using a transgenic reporter mouse for the GEVI ArcLight (Ai86(TITL-ArcLight)), which utilizes a Cre/tTA dependent expression system (TIGRE 1.0). Following pairing to appropriate Cre- and tTA transgenic mice, we report two mouse lines with ArcLight expression restricted to olfactory sensory neurons (OMP-ArcLight), and a subpopulation of interneurons that include periglomerular and granule cells (Emx1-ArcLight) in the olfactory bulb (OB). The ArcLight expression in these lines was sufficient for in vivo imaging of odorant responses in single trials. Odor responses were measured in the OB using epifluorescence and 2-photon imaging. The voltage responses were odor-specific and concentration-dependent, and confirmed earlier conclusions from calcium measurements. This study shows that the ArcLight Ai86(TITL-ArcLight) transgenic line is a flexible genetic tool that can be used to record neuronal electrical activity of a variety of cell types with a signal-to-noise ratio that is comparable to previous reports using viral transduction.

scholarly journals All-optical electrophysiology with improved genetically encoded voltage indicators reveals interneuron network dynamics in vivo

2021 ◽  
Author(s):  
He Tian ◽  
Hunter C. Davis ◽  
J. David Wong-Campos ◽  
Linlin Z. Fan ◽  
Benjamin Gmeiner ◽  
...  
Keyword(s):  
Gap Junction ◽  
Signal To Noise Ratio ◽  
Voltage Imaging ◽  
All Optical ◽  
Precision Voltage ◽  
Coupling Strengths ◽  
Junction Coupling ◽  
Multiple Cells ◽  
Voltage Indicator

All-optical electrophysiology can be a powerful tool for studying neural dynamics in vivo, as it offers the ability to image and perturb membrane voltage in multiple cells simultaneously. The "Optopatch" constructs combine a red-shifted archaerhodopsin (Arch)-derived genetically encoded voltage indicator (GEVI) with a blue-shifted channelrhodopsin actuator (ChR). We used a video-based pooled screen to evolve Arch-derived GEVIs with improved signal-to-noise ratio (QuasAr6a) and kinetics (QuasAr6b). By combining optogenetic stimulation of individual cells with high-precision voltage imaging in neighboring cells, we mapped inhibitory and gap junction-mediated connections, in vivo. Optogenetic activation of a single NDNF-expressing neuron in visual cortex Layer 1 significantly suppressed the spike rate in some neighboring NDNF interneurons. Hippocampal PV cells showed near-synchronous spikes across multiple cells at a frequency significantly above what one would expect from independent spiking, suggesting that collective inhibitory spikes may play an important signaling role in vivo. By stimulating individual cells and recording from neighbors, we quantified gap junction coupling strengths. Together, these results demonstrate powerful new tools for all-optical microcircuit dissection in live mice.

scholarly journals Imaging Subthreshold Voltage Oscillation With Cellular Resolution in the Inferior Olive in vitro

2020 ◽  
Vol 14 ◽  
Author(s):  
Kevin Dorgans ◽  
Bernd Kuhn ◽  
Marylka Yoe Uusisaari
Keyword(s):  
Inferior Olive ◽  
Brain Slices ◽  
Brain Regions ◽  
Mammalian Brain ◽  
Wide Field ◽  
Voltage Imaging ◽  
Subthreshold Oscillations ◽  
Cellular Resolution

Voltage imaging with cellular resolution in mammalian brain slices is still a challenging task. Here, we describe and validate a method for delivery of the voltage-sensitive dye ANNINE-6plus (A6+) into tissue for voltage imaging that results in higher signal-to-noise ratio (SNR) than conventional bath application methods. The not fully dissolved dye was injected into the inferior olive (IO) 0, 1, or 7 days prior to acute slice preparation using stereotactic surgery. We find that the voltage imaging improves after an extended incubation period in vivo in terms of labeled volume, homogeneous neuropil labeling with saliently labeled somata, and SNR. Preparing acute slices 7 days after the dye injection, the SNR is high enough to allow single-trial recording of IO subthreshold oscillations using wide-field (network-level) as well as high-magnification (single-cell level) voltage imaging with a CMOS camera. This method is easily adaptable to other brain regions where genetically-encoded voltage sensors are prohibitively difficult to use and where an ultrafast, pure electrochromic sensor, like A6+, is required. Due to the long-lasting staining demonstrated here, the method can be combined, for example, with deep-brain imaging using implantable GRIN lenses.

scholarly journals Transmission of tauopathy strains is independent of their isoform composition

2020 ◽  
Vol 11 (1) ◽  
Author(s):  
Zhuohao He ◽  
Jennifer D. McBride ◽  
Hong Xu ◽  
Lakshmi Changolkar ◽  
Soo-jung Kim ◽  
...  
Keyword(s):  
Human Brain ◽  
Transgenic Mouse ◽  
Mouse Line ◽  
Cell Type ◽  
Transgenic Mouse Line ◽  
Adult Human ◽  
Tau Isoforms ◽  
Underlying Mechanisms ◽  
Mouse Lines

AbstractThe deposition of pathological tau is a common feature in several neurodegenerative tauopathies. Although equal ratios of tau isoforms with 3 (3R) and 4 (4R) microtubule-binding repeats are expressed in the adult human brain, the pathological tau from different tauopathies have distinct isoform compositions and cell type specificities. The underlying mechanisms of tauopathies are unknown, partially due to the lack of proper models. Here, we generate a new transgenic mouse line expressing equal ratios of 3R and 4R human tau isoforms (6hTau mice). Intracerebral injections of distinct human tauopathy brain-derived tau strains into 6hTau mice recapitulate the deposition of pathological tau with distinct tau isoform compositions and cell type specificities as in human tauopathies. Moreover, through in vivo propagation of these tau strains among different mouse lines, we demonstrate that the transmission of distinct tau strains is independent of strain isoform compositions, but instead intrinsic to unique pathological conformations.

Real-time monitoring of stress erythropoiesis in vivo using Gata1 and β-globin LCR luciferase transgenic mice

Blood ◽  
2006 ◽  
Vol 108 (2) ◽  
pp. 726-733 ◽  
Author(s):  
Mikiko Suzuki ◽  
Kinuko Ohneda ◽  
Sakie Hosoya-Ohmura ◽  
Saho Tsukamoto ◽  
Osamu Ohneda ◽  
...  
Keyword(s):  
Real Time ◽  
Transgenic Mouse ◽  
Molecular Mechanisms ◽  
Real Time Monitoring ◽  
Erythroid Progenitors ◽  
Stress Erythropoiesis ◽  
Important Means ◽  
As Stress ◽  
Mouse Lines

Erythroid progenitors have the potential to proliferate rapidly in response to environmental stimuli. This process is referred to as stress erythropoiesis, with erythropoietin (EPO) playing central roles in its promotion. In this study, we wanted to elucidate the molecular mechanisms governing the regulation of stress erythropoiesis and the maintenance of red-cell homeostasis. This was achieved by our development of a noninvasive real-time monitoring system for erythropoiesis using transgenic mouse lines expressing luciferase under the control of the mouse Gata1 hematopoietic regulatory domain (G1-HRD-luc) or human β-globin locus control region (Hbb-LCR-luc). Optical bioluminescence images revealed that the luciferase was specifically expressed in spleen and bone marrow and was induced rapidly in response to anemia and hypoxia stimuli. The G1-HRD-luc activity tracked the emergence and disappearance of proerythroblast-stage progenitors, whereas the Hbb-LCR-luc activity tracked erythroblasts and later stage erythroid cells. Increased plasma EPO concentration preceded an increase in G1-HRD-luc, supporting our contention that EPO acts as the key upstream signal in stress erythropoiesis. Hence, we conclude that G1-HRD-luc and Hbb-LCR-luc reporters are differentially activated during stress erythropoiesis and that the transgenic mouse lines used serve as an important means for understanding the homeostatic regulation of erythropoiesis.

scholarly journals AAV ablates neurogenesis in the adult murine hippocampus

eLife ◽  
2021 ◽  
Vol 10 ◽  
Author(s):  
Stephen Johnston ◽  
Sarah Parylak ◽  
Stacy Kim ◽  
Nolan Mac ◽  
Christina Lim ◽  
...  
Keyword(s):  
Gene Therapy ◽  
Cell Death ◽  
Adult Neurogenesis ◽  
Granule Cells ◽  
Viral Vector ◽  
Cell Types ◽  
Early Gene ◽  
Post Injection

Recombinant adeno-associated virus (rAAV) has been widely used as a viral vector across mammalian biology and has been shown to be safe and effective in human gene therapy. We demonstrate that neural progenitor cells (NPCs) and immature dentate granule cells (DGCs) within the adult murine hippocampus are particularly sensitive to rAAV-induced cell death. Cell loss is dose dependent and nearly complete at experimentally relevant viral titers. rAAV-induced cell death is rapid and persistent, with loss of BrdU-labeled cells within 18 hours post-injection and no evidence of recovery of adult neurogenesis at 3 months post-injection. The remaining mature DGCs appear hyperactive 4 weeks post-injection based on immediate early gene expression, consistent with previous studies investigating the effects of attenuating adult neurogenesis. In vitro application of AAV or electroporation of AAV2 inverted terminal repeats (ITRs) is sufficient to induce cell death. Efficient transduction of the dentate gyrus (DG)-without ablating adult neurogenesis-can be achieved by injection of rAAV2-retro serotyped virus into CA3. rAAV2-retro results in efficient retrograde labeling of mature DGCs and permits in vivo 2-photon calcium imaging of dentate activity while leaving adult neurogenesis intact. These findings expand on recent reports implicating rAAV-linked toxicity in stem cells and other cell types and suggest that future work using rAAV as an experimental tool in the DG and as a gene therapy for diseases of the central nervous system (CNS) should be carefully evaluated.

scholarly journals Sources of off-target expression from recombinase-dependent AAV vectors and mitigation with cross-over insensitive ATG-out vectors

2019 ◽  
Vol 116 (52) ◽  
pp. 27001-27010 ◽  
Author(s):  
Kyle B. Fischer ◽  
Hannah K. Collins ◽  
Edward M. Callaway
Keyword(s):  
Gene Expression ◽  
Transgenic Mouse ◽  
Transgene Expression ◽  
Cell Types ◽  
Cell Type ◽  
Recognition Sites ◽  
Highly Sensitive ◽  
Plasmid Production ◽  
Targeted Gene Expression ◽  
Mouse Lines

In combination with transgenic mouse lines expressing Cre or Flp recombinases in defined cell types, recombinase-dependent adeno-associated viruses (AAVs) have become the tool of choice for localized cell-type-targeted gene expression. Unfortunately, applications of this technique when expressing highly sensitive transgenes are impeded by off-target, or “leak” expression, from recombinase-dependent AAVs. We investigated this phenomenon and find that leak expression is mediated by both infrequent transcription from the inverted transgene in recombinant-dependent AAV designs and recombination events during bacterial AAV plasmid production. Recombination in bacteria is mediated by homology across the antiparallel recombinase-specific recognition sites present in recombinase-dependent designs. To address both of these issues we designed an AAV vector that uses mutant “cross-over insensitive” recognition sites combined with an “ATG-out” design. We show that these CIAO (cross-over insensitive ATG-out) vectors virtually eliminate leak expression. CIAO vectors provide reliable and targeted transgene expression and are extremely useful for recombinase-dependent expression of highly sensitive transgenes.

scholarly journals Nuclear RNA-seq of single neurons reveals molecular signatures of activation

2016 ◽  
Vol 7 (1) ◽  
Author(s):  
Benjamin Lacar ◽  
Sara B. Linker ◽  
Baptiste N. Jaeger ◽  
Suguna Rani Krishnaswami ◽  
Jerika J. Barron ◽  
...  
Keyword(s):  
Gene Expression ◽  
Single Cell ◽  
Large Scale ◽  
Granule Cells ◽  
Mapk Pathway ◽  
Cell Types ◽  
Brain Regions ◽  
Activation Patterns ◽  
Environment Exposure

Abstract Single-cell sequencing methods have emerged as powerful tools for identification of heterogeneous cell types within defined brain regions. Application of single-cell techniques to study the transcriptome of activated neurons can offer insight into molecular dynamics associated with differential neuronal responses to a given experience. Through evaluation of common whole-cell and single-nuclei RNA-sequencing (snRNA-seq) methods, here we show that snRNA-seq faithfully recapitulates transcriptional patterns associated with experience-driven induction of activity, including immediate early genes (IEGs) such as Fos, Arc and Egr1. SnRNA-seq of mouse dentate granule cells reveals large-scale changes in the activated neuronal transcriptome after brief novel environment exposure, including induction of MAPK pathway genes. In addition, we observe a continuum of activation states, revealing a pseudotemporal pattern of activation from gene expression alone. In summary, snRNA-seq of activated neurons enables the examination of gene expression beyond IEGs, allowing for novel insights into neuronal activation patterns in vivo.

scholarly journals P2X-GCaMPs as versatile tools for imaging extracellular ATP signaling

2020 ◽  
Author(s):  
Matthias Ollivier ◽  
Juline Beudez ◽  
Nathalie Linck ◽  
Thomas Grutter ◽  
Vincent Compan ◽  
...  
Keyword(s):  
Signal To Noise Ratio ◽  
Atp Release ◽  
Cell Types ◽  
Extracellular Atp ◽  
P2x Receptor ◽  
High Signal ◽  
Calcium Sensors ◽  
Extracellular Signaling

AbstractAdenosine 5’ triphosphate (ATP) is an extracellular signaling molecule involved in numerous physiological and pathological processes. Yet, in situ characterization of the spatiotemporal dynamic of extracellular ATP is still challenging due to the lack of sensor with appropriate specificity, sensitivity and kinetics. Here we report the development of biosensors based on the fusion of cation permeable ATP receptors (P2X) to genetically encoded calcium sensors (GECI). By combining the features of P2X receptors with the high signal to noise ratio of GECIs, we generated ultrasensitive green and red fluorescent sniffers that detect nanomolar ATP concentrations in situ and also enable the tracking of P2X receptor activity. We provide the proof of concept that these sensors can dynamically track ATP release evoked by neuronal depolarization or by extracellular hypotonicity. Targeting these P2X-based biosensors to diverse cell types should advance our knowledge of extracellular ATP dynamics in vivo.

scholarly journals GluD2- and Cbln1-mediated Competitive Synaptogenesis Shapes the Dendritic Arbors of Cerebellar Purkinje Cells

2020 ◽  
Author(s):  
Yukari H. Takeo ◽  
S. Andrew Shuster ◽  
Linnie Jiang ◽  
Miley Hu ◽  
David J. Luginbuhl ◽  
...  
Keyword(s):  
Purkinje Cells ◽  
Synapse Formation ◽  
Granule Cells ◽  
Molecular Layer ◽  
Mammalian Brain ◽  
Dependent Manner ◽  
Genetic Epistasis ◽  
Cerebellar Purkinje Cells ◽  
Dendrite Morphogenesis

SUMMARYThe synaptotrophic hypothesis posits that synapse formation stabilizes dendritic branches, yet this hypothesis has not been causally tested in vivo in the mammalian brain. Presynaptic ligand cerebellin-1 (Cbln1) and postsynaptic receptor GluD2 mediate synaptogenesis between granule cells and Purkinje cells in the molecular layer of the cerebellar cortex. Here we show that sparse but not global knockout of GluD2 causes under-elaboration of Purkinje cell dendrites in the deep molecular layer and overelaboration in the superficial molecular layer. Developmental, overexpression, structure-function, and genetic epistasis analyses indicate that dendrite morphogenesis defects result from competitive synaptogenesis in a Cbln1/GluD2-dependent manner. A generative model of dendritic growth based on competitive synaptogenesis largely recapitulates GluD2 sparse and global knockout phenotypes. Our results support the synaptotrophic hypothesis at initial stages of dendrite development, suggest a second mode in which cumulative synapse formation inhibits further dendrite growth, and highlight the importance of competition in dendrite morphogenesis.

scholarly journals Cell types and clonal relations in the mouse brain revealed by single-cell and spatial transcriptomics

2021 ◽  
Author(s):  
Michael Ratz ◽  
Leonie von Berlin ◽  
Ludvig Larsson ◽  
Marcel Martin ◽  
Jakub Orzechowski Westholm ◽  
...  
Keyword(s):  
Single Cell ◽  
Progenitor Cells ◽  
Mouse Brain ◽  
High Throughput ◽  
Thin Sheet ◽  
Cell Types ◽  
Mammalian Brain ◽  
Fate Mapping ◽  
Cell Phenotypes

SummaryThe mammalian brain contains a large number of specialized cells that develop from a thin sheet of neuroepithelial progenitor cells1,2. Recently, high throughput single-cell technologies have been used to define the molecular diversity of hundreds of cell types in the nervous system3,4. However, the lineage relationships between mature brain cells and progenitor cells are not well understood, because transcriptomic studies do not allow insights into clonal relationships and classical fate-mapping techniques are not scalable5,6. Here we show in vivo barcoding of early progenitor cells that enables simultaneous profiling of cell phenotypes and clonal relations in the mouse brain using single-cell and spatial transcriptomics. We reconstructed thousands of clones to uncover the existence of fate-restricted progenitor cells in the mouse hippocampal neuroepithelium and show that microglia are derived from few primitive myeloid precursors that massively expand to generate widely dispersed progeny. By coupling spatial transcriptomics with clonal barcoding, we disentangle migration patterns of clonally related cells in densely labelled tissue sections. Compared to classical fate mapping, our approach enables high-throughput dense reconstruction of cell phenotypes and clonal relations at the single-cell and tissue level in individual animals and provides an integrated approach for understanding tissue architecture.

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