Project description:Fabry disease (FD) patients are known to be at high risk of developing neuropsychiatric symptoms such as anxiety, depression and cognitive deficits. Despite this, they are underdiagnosed and inadequately treated. It is unknown whether these symptoms arise from pathological glycosphingolipid deposits or from cerebrovascular abnormalities affecting neuronal functions in the central nervous system. We therefore aimed to fill this knowledge gap by exploring a transgenic FD mouse model with a combination of behavior, transcriptomic, functional and morphological assessments, with a particular focus on the hippocampus. Male FD mice exhibited increased anxiety-like behavior in the open field test, accompanied by a reduced exploratory drive in the Barnes maze, which could be related to the increased deposition of globotriaosylceramide (Gb3) identified in the dentate gyrus (DG). Hippocampus single-cell sequencing further revealed that Gb3 accumulation was associated with differential gene expression in neuronal and non-neuronal cell populations with granule, excitatory and interneurons, as well as microglia and endothelial cells as the main clusters with the most dysregulated genes. Particularly FD hippocampal neurons showed decreased electrical baseline activity in the DG and increased activity in the CA3 region of acutely dissected hippocampal slices. Our study highlights transcriptional and functional alterations in non-neuronal and neuronal cell clusters in the hippocampus of FD mice, which are suggested to be causally related to anxiety-like behavior developing as a consequence of FD pathology in mouse models of the disease and in patients.
Project description:MAP kinase signaling has been implicated in brain development, long-term memory, and the response to antidepressants. Inducible Braf knockout mice enabled us to unravel a new role of neuronal MAPK signaling for emotional behavior. Braf mice that were induced during adulthood showed normal anxiety but increased depression-like behavior, in accordance with pharmacological findings. In contrast, the inactivation of Braf in the juvenile brain leads to normal depression-like behavior but decreased anxiety in adults. In these mutants we found no alteration of GABAergic neurotransmission but reduced neuronal arborization in the dentate gyrus. Analysis of gene expression in the hippocampus revealed nine downregulated MAPK target genes that represent candidates to cause the mutant phenotype. Our results reveal the differential function of MAPK signaling in juvenile and adult life phases and emphasize the early postnatal period as critical for the determination of anxiety in adults. Moreover, these results validate inducible gene inactivation as new valuable approach, allowing to discriminate between gene function in the adult and the developing postnatal brain. Five male Braf-cko, six male homozygous Braf-flox littermates, six male heterozygous CamkII-Cre, and six male wildtype littermates were killed with CO2, the complete hippocampal tissue was prepared, and total RNA was extracted with the Trizol protocol. The integrity and quality of the RNA samples were analyzed with an RNA electrophoresis chip (RNA 6000 Nano Kit, Agilent, Boeblingen, Germany). RNA samples of high integrity and quality (RIN ≥ 7.5) were further processed with the TotalPrep RNA Amplification Kit (Ambion, Austin, TX, USA) and hybridized onto MouseWG-6 v1.1 Expression Bead-Chips (Illumina, San Diego, CA, USA) following manufacturer’s instructions. Data were analyzed using the software R (used packages: beadarray, limma, and vsn).
Project description:Investigating the molecular basis and correlates of anxiety-related and depression-like behaviors, we generated a mouse model consisting of high (HAB) and low (LAB) anxiety-related behavior mice. We utilized the elevated plus-maze for testing the genetic predisposition to anxiety-related behavior and, consequently, used this as selection criterion for the inbreeding of our animals. In depression-related tests, HAB mice display a more passive, depression-like coping strategy than LAB mice, resembling clinical comorbidity of anxiety and depression as observed in psychiatric patients. Using a microarray approach, the hypothalamic paraventricular nucleus (PVN), the basolateral/lateral (BLA), the medial (MeA) and central amygdala (CeA), the nucleus accumbens (NAc), the cingulate cortex (Cg) and the supraoptic nucleus (SON) – centers of the central nervous anxiety and fear circuitries – were investigated and screened for differences between HAB and LAB mice. Analysis was performed from six animals per line (HAB and LAB, respectively) pooled per brain region in ten technical replicates, thereof five with a dye-swapped design giving a total of 70 array slides analyzed. The LAB mouse line is referred to as reference.
Project description:SMC3 is a chromatin binding factor that plays central roles in genome organization and in proper neurodevelopment. Mutations in SMC3 gene (SMC3) induce neurodevelopmental and behavioral phenotypes in humans, including changes in anxiety behavior and self-injury. However, it is not clear what are the exact roles of SMC3 in behavior in adulthood or if its effects are only developmental. Using an adulthood forebrain excitatory neuron specific Smc3 knockout mouse model, the current study determined specific sex-dependent effects of SMC3 ablation during the adulthood. Behavioral tests identified anxiolytic effects of Smc3 knockout in females and anxiogenic effects in males four weeks after initiation of adulthood knockout. The prefrontal cortex, a regulator of anxiety behavior, also displayed sex-dependent effects in dendritic complexity. Transcriptional analysis revealed differential effects of Smc3 knockout in males and females, including changes in anxiety-related genes and relevant transcriptional pathways. While anxiety behavior was sex-specific, both males and females developed self-injury behavior at approximately ten weeks after induction of knockout. The current study demonstrates that neuronal SMC3 regulates anxiety during the adulthood in a sex-specific manner.
Project description:Emerging evidence has shown that noncoding RNAs, particularly microRNAs (miRNAs), contribute to the pathogenesis of mood and anxiety disorders, although the molecular mechanisms are poorly understood. Here we show altered levels of miR-17-92 in adult hippocampal neural progenitors have a significant impact in neurogenesis and anxiety- and depression-related behaviors in mice. miR-17-92 deletion in adult neural progenitors causes a decrease, while its overexpression an increase of neurogenesis in the dentate gyrus, through regulating genes in the glucocorticoid pathway, especially serum- and glucocorticoid-inducible protein kinase-1 (Sgk1). miR-17-92 knockout mice show anxiety- and depression-like behaviors, whereas miR-17-92 overexpressing mice exhibit anxiolytic and antidepression-like behaviors. Furthermore, we show that miR-17-92 expression in the adult mouse hippocampus responds to chronic stress, and miR-17-92 rescues proliferation defects, induced by corticosterone, in hippocampal neural progenitors. Our study uncovers a crucial role for miR-17-92 in adult neural progenitors to regulate neurogenesis and anxiety- and depression-like behaviors.
Project description:Anxiety disorders seriously damage our mental health, with chronic stress identified as a major etiologic factor. However, the precise neural mechanisms underlying the transition from chronic stress to anxiety remain unclear. In this study, with the chronic social defeat stress (CSDS) paradigm in mice, we verified a critical role of the parasubthalamic nucleus (PSTh) in anxiety regulation and found that CSDS results in a lasting increase in PSTh neuronal activity. Here, we explored the molecular substrates responsible for the increased intrinsic excitability of PSTh neurons following CSDS by RNA-sequence experiments. We found that CSDS downregulated Kcnd3 in PSTh neurons. Kcnd3 knockdown enhanced PSTh neuronal activity and produced anxiogenic effects in unstressed naïve mice, whereas overexpression of Kcnd3 in PSTh neurons dampened neuronal over-excitability and alleviated anxiety-like behavior in CSDS animals. Taken together, our results provide a cellular mechanism that the downregulated Kcnd3 induced by CSDS mediates intrinsic excitability of PSTh neurons, leading to anxiety-like behavior.
Project description:NG2 glia, also known as oligodendrocyte precursor cells (OPCs), play an important role in proliferation and give rise to myelinating oligodendrocytes during early brain development. In contrast to other glial cell types, the most intriguing aspect of NG2 glia is their ability to directly sense synaptic inputs from neurons. However, whether this synaptic interaction is bidirectional or unidirectional, or its physiological relevance has not yet been clarified. Here, we report that NG2 glia form synaptic complexes with hippocampal interneurons and that selective photostimulation of NG2 glia (expressing channelrhodopsin-2) functionally drives GABA release and enhances inhibitory synaptic transmission onto proximal interneurons in a microcircuit. The mechanism involves GAD67 biosynthesis and VAMP-2 containing vesicular exocytosis. Further, behavioral assays demonstrate that NG2 glia photoactivation triggers an anxiety-like behavior in vivo and induces anxiety-like behavior in a mouse model of chronic social defeat stress.
Project description:Investigating the molecular basis and correlates of anxiety-related and depression-like behaviors, we generated a mouse model consisting of high (HAB), normal (NAB) and low (LAB) anxiety-related behavior mice. We utilized the elevated plus-maze for testing the genetic predisposition to anxiety-related behavior and, consequently, used this as selection criterion for the inbreeding of our animals. In depression-related tests, HAB mice display a more passive, depression-like coping strategy than LAB mice, resembling clinical comorbidity of anxiety and depression as observed in psychiatric patients. Using a microarray approach, the hypothalamic paraventricular nucleus (PVN), the basolateral (BLA) and central amygdala (CeA), the cingulate cortex (Cg) and the dentate gyrus (DG) – centers of the central nervous anxiety and fear circuitries – were investigated and screened for differences between HAB, NAB and LAB mice. Analysis was performed from four to six animals per line (HAB, NAB and LAB from generation 25, respectively) per brain region, giving a total of 78 individual arrays analyzed. The LAB mouse line is referred to as reference.
Project description:This study reveals a novel mechanism linking social isolation to anxiety through a glucocorticoid (GC)-driven, ventral hippocampal (vHip)-specific iron-α-synuclein (α-Syn) axis. Social isolation activates glucocorticoid receptors (GRs) in vHip pyramidal neurons, which upregulate transferrin receptor 1 (TfR1) to promote iron accumulation. Elevated iron induces α-Syn overexpression, thereby enhancing presynaptic glutamate release and neuronal hyperexcitability in the vHip; this ultimately drives anxiety-like behaviors. Gain-of-function/loss-of-function experiments confirm that TfR1 and α-Syn are essential for this pathway, while intranasal iron chelation or α-Syn inhibition rescues both neural and behavioral abnormalities. These findings establish the GR-TfR1-α-Syn axis as a therapeutic target for social stress-related anxiety, which bridges metallobiology and psychiatric pathophysiology.
Project description:Embryonic exposure to the endocrine disruptor vinclozolin during gonadal sex determination promotes an epigenetic reprogramming of the male germ-line that is associated with transgenerational adult onset disease states. Further analysis of this transgenerational phenotype on the brain demonstrated reproducible changes in the brain transcriptome three generations (F3) removed from the exposure. The transgenerational alterations in the male and female brain transcriptomes were distinct. In the males, the expression of 92 genes in the hippocampus and 276 genes in the amygdala were transgenerationally altered. In the females, the expression of 1,301 genes in the hippocampus and 172 genes in the amygdala were transgenerationally altered. Analysis of specific gene sets demonstrated that several brain signaling pathways were influenced including those involved in axon guidance and long-term potentiation. An investigation of behavior demonstrated that the vinclozolin F3 generation males had a decrease in anxiety-like behavior, while the females had an increase in anxiety-like behavior. These observations demonstrate that an embryonic exposure to an environmental compound appears to promote a reprogramming of brain development that correlates with transgenerational sex-specific alterations in the brain transcriptomes and behavior. Observations are discussed in regards to environmental and transgenerational influences on the etiology of brain disease. Keywords: expression analysis, transgenerational changes due to vinclozolin