Corticohippocampal circuit dysfunction in a mouse model of Dravet syndrome
- The University of Pennsylvania School of Medicine, United States
- The Children's Hospital of Philadelphia, United States
- Children's Hospital of Philadelphia, United States
- The University of Pennsylvania, United States
Abstract
Dravet syndrome (DS) is a neurodevelopmental disorder due to pathogenic variants in SCN1A encoding the Nav1.1 sodium channel subunit, characterized by treatment-resistant epilepsy, temperature-sensitive seizures, developmental delay/intellectual disability with features of autism spectrum disorder, and increased risk of sudden death. Convergent data suggest hippocampal dentate gyrus (DG) pathology in DS (Scn1a+/-) mice. We performed two-photon calcium imaging in brain slice to uncover a profound dysfunction of filtering of perforant path input by DG in young adult Scn1a+/- mice. This was not due to dysfunction of DG parvalbumin inhibitory interneurons (PV-INs), which were only mildly impaired at this timepoint; however, we identified enhanced excitatory input to granule cells, suggesting that circuit dysfunction is due to excessive excitation rather than impaired inhibition. We confirmed that both optogenetic stimulation of entorhinal cortex and selective chemogenetic inhibition of DG PV-INs lowered seizure threshold in vivo in young adult Scn1a+/- mice. Optogenetic activation of PV-INs, on the other hand, normalized evoked responses in granule cells in vitro. These results establish the corticohippocampal circuit as a key locus of pathology in Scn1a+/- mice and suggest that PV-INs retain powerful inhibitory function and may be harnessed as a potential therapeutic approach towards seizure modulation.
Data availability
All data generated or analyzed during this study are included in the manuscript and supporting files. Source data files for all Figures (1-8) and Tables (1-2) have been included and are also available via G-Node at:https://gin.g-node.org/GoldbergNeuroLab/Mattis-et-al-2022.Source code has been made available here:https://github.com/GoldbergNeuroLab/Mattis-et-al.-2022
-
Mattis-et-al-2022G_Node, 10.12751/g-node.jubxbd.
Article and author information
Author details
Ethan Michael Goldberg
Funding
National Institute of Neurological Disorders and Stroke (R25 NS065745)
- Joanna H Mattis
National Institute of Neurological Disorders and Stroke (K08 NS097633)
- Ethan Michael Goldberg
National Institute of Neurological Disorders and Stroke (R01 NS110869)
- Ethan Michael Goldberg
Dana Foundation (David Mahoney Neuroimaging Grant)
- Ethan Michael Goldberg
Burroughs Wellcome Fund (Career Award for Medical Scientists)
- Ethan Michael Goldberg
National Institute of Neurological Disorders and Stroke (K08 NS121464)
- Joanna H Mattis
Institute for Translational Medicine and Therapeutics (Translational Biomedical Imaging Center (TBIC))
- Joanna H Mattis
- Ethan Michael Goldberg
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: This study was performed in strict accordance with the recommendations in the Guide for the Care and Use of Laboratory Animals of the National Institutes of Health. All of the animals were handled according to approved institutional animal care and use committee (IACUC) protocol 21-001152 of The Children's Hospital of Philadelphia. All surgery was performed under isoflurane anesthesia, and every effort was made to minimize suffering.
Copyright
© 2022, Mattis et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 2,709
- views
-
- 391
- downloads
-
- 34
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Corticohippocampal circuit dysfunction in a mouse model of Dravet syndrome
eLife 11:e69293.
https://doi.org/10.7554/eLife.69293
Further reading
-
- Genetics and Genomics
- Microbiology and Infectious Disease
The ability to analyze the function of all genes in a genome is highly desirable, yet challenging in Leishmania due to a repetitive genome, limited DNA repair mechanisms, and lack of RNA interference in most species. While our introduction of a cytosine base editor (CBE) demonstrated potential to overcome these limitations (Engstler and Beneke, 2023), challenges remained, including low transfection efficiency, variable editing rates across species, parasite growth effects, and competition between deleterious and non-deleterious mutations. Here, we present an optimized approach addressing these issues. We identified a T7 RNAP promoter variant ensuring high editing rates across Leishmania species without compromising growth. A revised CBE single-guide RNAs (sgRNAs) scoring system was developed to prioritize STOP codon generation. Additionally, a triple-expression construct was created for stable integration of CBE sgRNA expression cassettes into a Leishmania safe harbor locus using AsCas12a ultra-mediated DNA double-strand breaks, increasing transfection efficiency by ~400-fold to 1 transfectant per 70 transfected cells. Using this improved system for a small-scale proof-of-principle pooled screen, we successfully confirmed the essential and fitness-associated functions of CK1.2, CRK2, CRK3, AUK1/AIRK, TOR1, IFT88, IFT139, IFT140, and RAB5A in Leishmania mexicana, demonstrating a significant improvement over our previous method. Lastly, we show the utility of co-expressing AsCas12a ultra, T7 RNAP, and CBE for hybrid CRISPR gene replacement and base editing within the same cell line. Overall, these improvements will broaden the range of possible gene editing applications in Leishmania species and will enable a variety of loss-of-function screens in the near future.
-
- Genetics and Genomics
- Neuroscience
Spinal muscular atrophy (SMA) is caused by mutations in the Survival Motor Neuron 1 (SMN1) gene. While traditionally viewed as a motor neuron disorder, there is involvement of various peripheral organs in SMA. Notably, fatty liver has been observed in SMA mouse models and SMA patients. Nevertheless, it remains unclear whether intrinsic depletion of SMN protein in the liver contributes to pathology in the peripheral or central nervous systems. To address this, we developed a mouse model with a liver-specific depletion of SMN by utilizing an Alb-Cre transgene together with one Smn2B allele and one Smn1 exon 7 allele flanked by loxP sites. Initially, we evaluated phenotypic changes in these mice at postnatal day 19 (P19), when the severe model of SMA, the Smn2B/- mice, exhibit many symptoms of the disease. The liver-specific SMN depletion does not induce motor neuron death, neuromuscular pathology or muscle atrophy, characteristics typically observed in the Smn2B/- mouse at P19. However, mild liver steatosis was observed, although no changes in liver function were detected. Notably, pancreatic alterations resembled that of Smn2B/-mice, with a decrease in insulin-producing β-cells and an increase in glucagon-producingα-cells, accompanied by a reduction in blood glucose and an increase in plasma glucagon and glucagon-like peptide (GLP-1). These changes were transient, as mice at P60 exhibited recovery of liver and pancreatic function. While the mosaic pattern of the Cre-mediated excision precludes definitive conclusions regarding the contribution of liver-specific SMN depletion to overall tissue pathology, our findings highlight an intricate connection between liver function and pancreatic abnormalities in SMA.
