シンポジウム
08 精神疾患の多階層的理解
08 Multi-scale understanding of mental disorders
座長：加藤 忠史（順天堂大学医学部精神医学講座）・林（高木） 朗子（理化学研究所脳神経科学研究センター） |
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| 2022年7月2日 14:00～14:20 沖縄コンベンションセンター 会議場A1 第2会場
3S02a-01
ストレス病態の多階層的理解
Multiscale understanding of stress pathology
*古屋敷 智之(1)
1. 神戸大学大学院医学研究科
*Tomoyuki Furuyashiki(1)
1. Grad Sch Med, Kobe Univ, Hyogo, Japan
Keyword: STRESS, DEPRESSION, SYNAPSE, MICROGLIA
Chronic social stress leads to emotional and cognitive disturbances and precipitates mental illness, including depression. Clinical studies with depressive patients have shown the association between depression and inflammation, and rodent studies have demonstrated the roles of microglia-driven neuroinflammation in chronic social stress-induced neuronal and behavioral changes. However, how chronic social stress alters neuronal morphology and functions and how neuroinflammation is integrated into this process remain unknown. Here we performed multi-layer omics and ultrastructural analyses in the medial prefrontal cortex of stressed mice with chronic social defeat stress. Social defeat stress altered central metabolic pathways at synapses in the medial prefrontal cortex. Manipulation of central metabolic pathways ameliorated stress-induced behavioral changes, suggesting their functional significance for stress pathology. In parallel, social defeat stress altered transcriptome profiles in prefrontal microglia, including altered expression in phagocytosis-related genes. Structurally, social defeat stress induced partial phagocytosis of synapses by microglial processes in the medial prefrontal cortex. These findings collectively show that chronic social stress induces the synapse-microglia interface associated with synaptic metabolic changes and microglial phagocytic activity in the medial prefrontal cortex as a possible mechanism binding separate multiscale events into an integrated stress pathology. This symposium will introduce some of our recent findings described above and discuss their relevance to mental illness pathology and therapeutic intervention. | | 2022年7月2日 14:20～14:40 沖縄コンベンションセンター 会議場A1 第2会場
3S02a-02
即効性抗うつ作用の基盤となるシナプスのメカニズム
Synaptic mechanisms underlying rapid antidepressant action
*鈴木 敢三(1)、Kim Ji-Woon (1)、Elena Nosyreva(2)、Ege T Kavalali(1)、Lisa M Monteggia(1)
1. ヴァンダービルト大学、2. テキサス大学サウスウエスタンメディカルセンター
*Kanzo Suzuki(1), Kim Ji-Woon (1), Elena Nosyreva(2), Ege T Kavalali(1), Lisa M Monteggia(1)
1. Vanderbilt University, 2. University of Texas Southwestern Medical Center
Keyword: Rapid antidepressant, Major depressive disorder , Synaptic scaling
Major depressive disorder is one of the most prevalent mental disorders. Traditional antidepressants, which target the monoamine system, are commonly used for the treatment of depression but typically take several weeks to exert a clinical effect, with a sizable fraction of the patient population failing to respond to treatment. This therapeutic delay in onset is a major limitation of traditional antidepressant therapies especially for individuals at risk for suicide. Thus, there has been a major unmet need for the development of pharmacological therapies that can quickly and effectively alleviate symptoms associated with depression. Ketamine is a noncompetitive glutamatergic N-methyl-D-aspartate receptor (NMDAR) antagonist with rapid antidepressant efficacy for patients with treatment-resistant major depressive disorder. We have been investigating the mechanisms underlying the efficacy of rapid antidepressant action using preclinical animal models. We previously showed that ketamine blocks NMDARs activated by spontaneous glutamate release (also referred to as “at rest”) that couples to eukaryotic elongation factor 2 kinase (eEF2K) signaling. This signaling pathway subsequently results in increased protein synthesis, including brain-derived neurotrophic factor (BDNF) and alpha-amino-3-hydroxy-5-methylisoxazole-4-propinic acid receptors (AMPARs), induces synaptic scaling at CA3-CA1 synapses that is necessary for rapid antidepressant-like effects. To better understand key synaptic mechanisms underlying rapid antidepressant action, we extensively characterized the role of eEF2K in synaptic function. We find that acute, but not chronic, suppression of eEF2K elicits synaptic scaling. Previous work has shown retinoic acid (RA) signaling also elicits a similar form of rapid synaptic scaling in the hippocampus, which we found occurs in an eEF2K independent manner. RA signaling was also not required for ketamine-mediated antidepressant action, however direct activation of RA signaling elicits synaptic scaling and rapid antidepressant-like action. Collectively, our findings suggest these two independent signaling pathways converge at a common synaptic endpoint and produce rapid antidepressant-like action. We will present our recent findings demonstrating that multiplicative synaptic scaling is a key synaptic mechanism to produce rapid antidepressant action. | | 2022年7月2日 14:40～15:00 沖縄コンベンションセンター 会議場A1 第2会場
3S02a-03
Mapping the Cell Type-Specific Regulome of PTSD
*Matthew Girgenti(1,2), Mario Skarica(3), Jing Zhang(4), Ahyeon Hwang(4), Jiawei Wang(5), Hongyu Li(5), Hongyu Zhao(5), Nenad Sestan(3), John Krystal(1,2)
1. Department of Psychiatry, Yale School of Medicine, New Haven, CT, 2. National Center for PTSD, 3. Department of Neuroscience, Yale School of Medicine, New Haven, CT, 4. Department of Computer Science, University of California, Irvine, CA , 5. Department of Biostatistics, Yale School of Public Health, New Haven, CT
Keyword: PTSD, Transcriptomics, ATAC, postmortem
Post-traumatic stress disorder is a multigenic disorder occurring in the aftermath of severe trauma exposure. Recent studies have begun to detail the molecular biology of the postmortem PTSD brain using bulk-tissue transcriptomic and epigenetic analyses. Studies from our lab have identified massive changes to the prefrontal cortex of donors with PTSD. Transcriptome-wide association analysis (TWAS) has allowed us to match PTSD causal genes with cis-regulated expression changes to genetic risk loci for PTSD, including the interneuron key driver ELFN1 and other transcripts involved with glucocorticoid signaling and inflammatory responses. However, given the array of PTSD-perturbed molecular pathways identified thus far, it is unlikely that a single cell type is responsible. It is therefore necessary to uncover the individual cell type contributions to the molecular pathology of PTSD. We have isolated ~2.2M nuclei from human postmortem dorsolateral prefrontal cortex cases and controls for single nucleus RNA sequencing across three diagnostic cohorts: PTSD, MDD (Psychiatric control), and normal controls to identify neuronal and non-neuronal cell type clusters and cell type-specific gene expression changes. We then performed ATAC-sequencing, to measure chromatin accessibility from these same nuclei. We identified open genomic regions harboring risk alleles for PTSD and integrated our RNA and ATAC datasets. We identified 39 distinct cell type clusters including neuronal and non-neuronal cell types. We also identified over 800 FDR significant differentially expressed genes across many cell types and confirmed expression changes of several genes implicated in PTSD pathophysiology including ELFN1, FKBP5, and SGK1. By adding an additional molecular modality- chromatin accessibility, we were able to improve our transcript based clustering and identify a consistent relationship between chromatin accessibilities and mRNA levels providing unparalleled molecular resolution at the individual cell-type level. This work is the first step in the creation of a cell type-specific atlas of stress disorders. These findings provide a global picture of the cell type-specific molecular regulatory mechanisms that govern stress effects on the human frontal cortex. Additionally, applying functional genomic approaches to characterize risk alleles within specific cell types may help determine which neurotypical processes are most impacted by stress. | | 2022年7月2日 15:00～15:20 沖縄コンベンションセンター 会議場A1 第2会場
3S02a-04
Multi-scale approaches to uncover the neurobiology of vulnerability for psychosis
*Gemma Modinos(1)
1. Institute of Psychiatry, Psychology & Neuroscience; King's College London
Keyword: Neuroimaging, Psychosis, Cross-species, Inhibitory interneurons
Multiple lines of evidence suggest that psychosis develops as a result of GABAergic inhibitory interneuron dysfunction. Such dysfunction is associated with increased activity of the hippocampus, likely driven by disinhibition of glutamatergic (excitatory) neurons, and linked to not only psychotic symptoms but also cognitive deficits that are not treated effectively by current antipsychotics. Using multimodal neuroimaging we showed that hippocampal hyperactivity is associated with (1) cortical GABA levels and (2) striatal dopamine function in people at clinical high-risk for psychosis who subsequently develop adverse outcomes. However, a key barrier for translation of neuroimaging-based metrics into the clinic is that we lack precise knowledge about how these are linked to dysfunction at the cellular level, knowledge that is critical for mechanism-based drug development.
One way to address this issue is to back-translate these measures into relevant animal models. First, I will present new data characterising neurochemical and neurophysiological effects of cortical inhibitory interneuron disruption by using multimodal in vivo neuroimaging in mice with conditional genetic manipulation of the tyrosine kinase receptor ErbB4 in cortical PV+ interneurons. ErbB4 mutants showed increased glutamine levels and resting cerebral blood flow, and decreased synaptic density, in hippocampus relative to WT littermates. These results support the involvement of inhibitory interneuron disruption in key neuroimaging phenotypes associated with psychosis in humans.
Next, our recent data on a different, neurodevelopmental rodent model of psychosis (the methylazoxymethanol acetate (MAM) model) using quantitative receptor autoradiography showed that a5GABAAR density was lower in the ventral hippocampus while NMDAR density was higher in the dorsal hippocampus of MAM-treated rats compared to saline-treated rats. These findings implicate a5GABAAR abnormalities in psychosis pathophysiology, and provide new empirical support to the notion that the development of pharmacological agents with selectivity for hippocampal a5GABAAR may be a promising new therapeutic target.
Finally, I will present our new findings using state-of-the-art imaging transcriptomics to decode the cellular and molecular signatures of two gold-standard PET radiotracers for quantifying GABAergic neurotransmission in vivo in the human brain. We identified that the distribution of the inhibitory interneuron marker SST differentially tracks the distribution of [11C]Ro15-4513 binding, whereas the distribution of the marker PV tracks the distribution of [11C]flumazenil binding. These results may inform methodological choices for imaging the GABAergic system within a framework that bridges the gap between genes, cells and whole-brain neuroimaging. | | 2022年7月2日 15:20～15:40 沖縄コンベンションセンター 会議場A1 第2会場
3S02a-05
Single-cell transcriptomic and regulatory signatures of the depressed brain
*Gustavo Turecki(1)
1. McGill University
Keyword: single-cell genomics, major depressive disorder, postmortem human brain, ATAC-Seq
Background: Understanding molecular changes associated with major depression at single-cell resolution is key to better understand the illness and develop new treatments.
Methods: Initially, we isolated N~80,000 nuclei from the prefrontal cortex (PFC) of cases and controls for single nucleus RNA sequencing (Nagy et al Nat Neurosc, 2020). We then used snATAC-seq to profile chromatin accessibility in the same samples. For snATAC-seq high-quality barcodes were called as cells using transcription start site signal-to-noise ratio and total unique fragments per cell. We annotated and compared cell-types using Seurat and ArchR. Co-accessible regulatory sites and distal regulators of gene expression were identified by Cicero. Finally, we integrated snRNA-Seq and snATAC-Seq data using Seurat-based canonical correlation analysis, to identify cross-modality features associated with depression. To identify causal epigenetic mechanisms, we perform stratified LD score regression to partition heritability from MDD GWAS summary statistics to cell-type specific features. Results: Our transcriptomic results implicate 96 genes differentially expressed in 16 cells types, particularly lower layer excitatory neurons and immature oligodendrocytes. The addition of a modality—chromatin accessibility, improved and refined the transcript-only based clustering. We were able to identify a consistent relationship between chromatin profiles and transcript levels providing further insight into the involvement and relationship of individual cell types. Our data showed an enrichment of open chromatin at functional non-coding regions, while enhancer regions showed the most cell specific patterning. Differential open chromatin regions between cases and controls showed enrichment for gene regulatory regions and transcription factor binding motifs associated with disease-related biological pathways. We also identified gene regulators with cell-type specificity, and disease-specific epigenetic signatures of differential gene expression patterns.
Conclusion: Leveraging the power of single cell technologies has allowed us to produce cell-type specific epigenetic signature. Specifically, we have identified cell types mostly affected in depression, as well as chromatin accessibility architecture that partly explains expression patterns associated with this illness. | | | |
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