Project description:The formation of long-term memory requires signaling from the synapse to the nucleus to mediate neuronal activity-dependent gene transcription. Synapse-to-nucleus communication is initiated by influx of calcium ions through synaptic NMDA receptors and/or L-type voltage-gated calcium channels and involves the activation of transcription factors by calcium/calmodulin signaling in the nucleus. Recent studies have drawn attention to a new family of transcriptional regulators, the so-called calmodulin-binding transcription activator (CAMTA) proteins. CAMTAs are expressed at particularly high levels in the mouse and human brain, and we reasoned that, as calmodulin-binding transcription factors, CAMTAs may regulate the formation of long-term memory by coupling synaptic activity and calcium/calmodulin signaling to memory-related transcriptional responses. This hypothesis is supported by genetic studies that reported a correlation between CAMTA gene polymorphisms or mutations and cognitive capability in humans. Here, we show that acute knock-down of CAMTA1, but not CAMTA2, in the hippocampus of adult mice results in impaired performance in two memory tests, contextual fear conditioning and object-place recognition test. Short-term memory and neuronal morphology were not affected by CAMTA knock-down. Gene expression profiling in the hippocampus of control and CAMTA knock-down mice revealed a number of putative CAMTA1 target genes related to synaptic transmission and neuronal excitability. Patch clamp recordings in organotypic hippocampal slice cultures provided further evidence for CAMTA1-dependent changes in electrophysiological properties. In summary, our study provides experimental evidence that confirms previous human genetic studies and establishes CAMTA1 as a regulator of long-term memory formation.
Project description:Neurons utilize glucose to generate adenosine triphosphate (ATP) essential for their survival, excitability and synaptic signaling, as well as initiating changes in neuronal structure and function. Defects in oxidative metabolism and mitochondria functions are also associated with aging and diverse human neurological diseases1-4. While neurons are known to adapt their metabolism to meet the increased energy demands of complex behaviors such as learning and memory, the molecular underpinnings regulating this process remain poorly understood4-6. Here we show that the orphan nuclear receptor estrogen related receptor gamma (ERRγ) becomes highly expressed during retinoic-acid induced neurogenesis and is widely expressed in neuronal nuclei throughout the brain. Mechanistically, we show that ERRγ directly orchestrates the expression of networks of genes involved in mitochondrial oxidative phosphorylation and energy generation in neurons. The importance of this regulation is evidenced by decreased adaptive metabolic capacity in cultured neurons lacking ERRγ, and reduced long-term potentiation (LTP) in ERRγ-/- hippocampal slices. Notably, the defect in LTP was rescued by the metabolic intermediate pyruvate, functionally linking the ERRγ knockout metabolic phenotype and memory formation. Consistent with this notion, mice lacking neuronal ERRγ exhibit defects in spatial learning and memory. These findings implicate ERRγ in the metabolic adaptations required for long-term memory formation. We used microarray analysis to compare the genome-wide gene expression changes between wild type (WT) and ERRγ-/- P0 cerebral cortex as it contains mainly neuronal lineage at this stage compared to adult cortex.
Project description:Neurons utilize glucose to generate adenosine triphosphate (ATP) essential for their survival, excitability and synaptic signaling, as well as initiating changes in neuronal structure and function. Defects in oxidative metabolism and mitochondria functions are also associated with aging and diverse human neurological diseases1-4. While neurons are known to adapt their metabolism to meet the increased energy demands of complex behaviors such as learning and memory, the molecular underpinnings regulating this process remain poorly understood4-6. Here we show that the orphan nuclear receptor estrogen related receptor gamma (ERRγ) becomes highly expressed during retinoic-acid induced neurogenesis and is widely expressed in neuronal nuclei throughout the brain. Mechanistically, we show that ERRγ directly orchestrates the expression of networks of genes involved in mitochondrial oxidative phosphorylation and energy generation in neurons. The importance of this regulation is evidenced by decreased adaptive metabolic capacity in cultured neurons lacking ERRγ, and reduced long-term potentiation (LTP) in ERRγ-/- hippocampal slices. Notably, the defect in LTP was rescued by the metabolic intermediate pyruvate, functionally linking the ERRγ knockout metabolic phenotype and memory formation. Consistent with this notion, mice lacking neuronal ERRγ exhibit defects in spatial learning and memory. These findings implicate ERRγ in the metabolic adaptations required for long-term memory formation. We used ChIP-Seq analysis to determine the genome-wide binding of ERRγ in neurons derived from ES cells.
Project description:Interventions: Case series:Nil
Primary outcome(s): intestinal microecological disorders;blood non-coding RNAs and immune status
Study Design: Randomized parallel controlled trial
Project description:Memory encodes past experiences, thereby enabling future plans. The basolateral amygdala (BLA) is a center of salience networks that underlie emotional experiences and thus plays a key role in long-term fear memory formation. Here we used single-cell transcriptomics to illuminate the cellular and molecular architecture of the role of the basolateral amygdala in long-term memory. We identified transcriptional signatures in subpopulations of neurons and astrocytes that were memory-specific and persisted for weeks. These transcriptional signatures implicate neuropeptide and brain-derived neurotrophic factor (BDNF) signaling, mitogen-activated protein kinase (MAPK) and cAMP response element-binding protein (CREB) activation, ubiquitination pathways, and synaptic connectivity as key components of long-term memory. Strikingly, upon long-term memory formation a neuronal sub-population defined by increased Penk and decreased Tac expression constituted the most prominent component of the BLA’s memory engram.
Project description:Neurogenesis is a pro-survival process that comprises of dendritic and axonal growth, synaptogenesis, synaptic and neuronal pruning. These complex processes are determined by temporal gene expression during development, which is in turn tightly regulated by long non-coding RNAs and microRNAs. In this study, we investigated the processes implicated in the maturation of primary neuronal cultures based on RNA expression profiling. Correlation between neuron specific gene ontologies of mRNA and non-coding RNAs identified direct regulation of axonogenesis and dendritogenesis. Temporally regulated mRNA and their associated long non-coding RNAs were significantly overrepresented in proliferation and differentiation associated signalling, cell adhesion molecules and neurotrophin signalling pathways during neuronal maturation. Long non-coding RNAs associated with Axin2, Cntn1, Ncam1, Negr1, Ntrk2, Nrxn1 and Sh2b3 displayed an inverse expression profile to their mRNA whereas long non-coding RNA -mRNA pairs for Kit, Prkcb and Ralgds displayed similar expression profiles. These genes were also predicted targets of the altered miRNAs, miR-124, -128, -129-5p, -203, -218, -290-5p, -326, -329, -377 and -495. These microRNAs particularly regulate the cell adhesion molecules, Cntn1, Ncam1, Negr1 and Nrxn1 that determine axonogenesis and dendritogenesis, supporting the observed co-regulation of these biological processes by non-coding RNAs. Verification of expression of these long non-coding RNA-mRNA pairs in an in vitro model of ischemic-reperfusion injury showed an inverse expression profile, thus confirming their role(s) in maintenance of the neuronal structure and function. This neuronal transcriptome (mRNAs, lncRNAs, miRNAs) is in turn orchestrated by C/EBPM-NM-1/M-NM-2 transcription factors and CTCF, thereby governing intricate control of neuronal development. microRNA expression profiling of maturing primary cortical neurons from E15 mouse embryos. Maturing neurons were harvested on Days 2, 4, 6 and 8.
Project description:We show that traumatic stress experienced by males in early postnatal life impairs memory in their offspring, blocks long-term potentiation (LTP) and favors long-term depression (LTD). These effects are accompanied by suppression of key molecular pathways involved in neuronal plasticity both at rest and after acute stress. Male mice were exposed to chronic traumatic stress in early postnatal life and were later bred to naM-CM-/ve females to produce second-generation offspring. Memory performance was evaluated in the offspring, and synaptic plasticity was examined in the hippocampus and the amygdala, brain areas important for memory formation. The two groups tested were 1: offspring of fathers which were stressed (MSUS - maternal separation unpredictable stress) and 2: offspring of non-stressed fathers (control). Genome-wide gene expression in hippocampus of these two groups was assessed at rest and after acute stress (this study).