Project description:Despite the rapid progress in dissecting neural circuits for social behaviors, it remains unknown whether specific neural cell types are selectively vulnerable in social dysfunction cases often associated with neurodevelopmental disorders. Here, employing a single-cell transcriptome analysis in mice, we show that an embryonic disturbance known to induce social dysfunction preferentially impairs gene expressions crucial for neural functions in parvocellular oxytocin (OT) neurons—a subtype linked to social rewards—while neighboring cell types experience a lesser impact. Chemogenetic stimulation of OT neurons at the neonatal stage ameliorated social deficits, concomitant with a cell-type-specific sustained recovery of the pivotal gene expressions. Our data illuminates the transcriptomic selective vulnerability within the hypothalamic social behavioral center, offering a potential therapeutic target through specific neonatal neurostimulation.
Project description:Social interactions are critical components for the survival of mammalian biology and evolution. Dysregulation of social behavior often leads to psychopathologies such as social anxiety disorder, which is characterized by an intense fear and avoidance of social situations. Using the social fear conditioning (SFC) paradigm, we analyzed expression levels of miR-132-3p and miR-124-3p within the septum, a brain region essential for social behavior and fear, after acquisition and extinction of social fear. Functional in vivo approaches using pharmacology, functional inhibition of miR-132-3p, viral miR-132 overexpression and shRNA-mediated knockdown of miR-132-3p within oxytocin receptor positive neurons confirmed septal miR-132-3p to be involved in social fear extinction and the oxytocin-mediated reversal of social fear. Moreover, Argonaute-RNA-co-immunoprecipitation-microarray analysis and further target mRNA quantification, depicted growth differentiation factor-5 (GDF-5) to be involved in miR-132-3p-mediated regulation of social fear extinction. Local application of GDF-5 resulted in impaired social fear extinction, an effect which seems to be mediated by miR-132-3p. In summary, we show that septal miR-132-3p is functionally involved in social fear extinction learning and oxytocin-mediated reversal of social fear.
Project description:Social behavioral changes are a hallmark of several neurodevelopmental and neuropsychiatric conditions, nevertheless the underlying neural substrates of such dysfunction remain poorly understood. Building evidence points to the prefrontal cortex (PFC) as one of the key brain regions that orchestrates social behavior. We used this concept with the aim to develop a translational rat model of social-circuit dysfunction, the chronic PFC activation model (CPA). Chemogenetic designer receptor hM3Dq was used to induce chronic activation of the PFC over 10 days, and the behavioral and electrophysiological signatures of prolonged PFC hyperactivity were evaluated. To test the sensitivity of this model to pharmacological interventions on longer timescales, and validate its translational potential, the rats were treated with our novel highly selective oxytocin receptor (OXTR) agonist RO6958375, which is not activating the related vasopressin V1a receptor. CPA rats showed reduced sociability in the three-chamber sociability test, and a concomitant decrease in neuronal excitability and synaptic transmission within the PFC as measured by electrophysiological recordings in acute slice preparation. Sub-chronic treatment with a low dose of the novel OXTR agonist following CPA interferes with the emergence of PFC circuit dysfunction, abnormal social behavior and specific transcriptomic changes. These results demonstrate that sustained PFC hyperactivity modifies circuit characteristics and social behaviors in ways that can be modulated by selective OXTR activation and that this model may be used to understand the circuit recruitment of prosocial therapies in drug discovery.
Project description:One of the most fundamental challenges in developing treatments for autism-spectrum disorders is the heterogeneity of the condition. More than one hundred genetic mutations confer high risk for autism, with each individual mutation accounting for only a small fraction of autism cases. Subsets of risk genes can be grouped into functionally-related pathways, most prominently synaptic proteins, translational regulation, and chromatin modifications. To possibly circumvent this genetic complexity, recent therapeutic strategies have focused on the neuropeptides oxytocin and vasopressin which regulate aspects of social behavior in mammals. However, whether genetic risk factors might predispose to autism due to modification of oxytocinergic signaling remains largely unknown. Here, we report that an autism-associated mutation in the synaptic adhesion molecule neuroligin-3 (Nlgn3) results in impaired oxytocin signaling in dopaminergic neurons and in altered social novelty responses in mice. Surprisingly, loss of Nlgn3 is accompanied by a disruption of translation homeostasis in the ventral tegmental area. Treatment of Nlgn3KO mice with a novel, highly specific, brain-penetrant inhibitor of MAP-kinase interacting kinases resets mRNA translation and restores oxytocin and social novelty responses. Thus, this work identifies an unexpected convergence between the genetic autism risk factor Nlgn3, translational regulation, and oxytocinergic signaling. Focus on such common core plasticity elements might provide a pragmatic approach to reduce the heterogeneity of autism phenotypes. Ultimately, this would allow for mechanism-based stratification of patient populations to increase the success of therapeutic interventions.
Project description:Rates of oxytocin use to induce or augment labor are increasing in the United States with little understanding of the impact on offspring development. Using a prairie vole animal model, we have shown that oxytocin administered to mothers can reach offspring brains with long lasting impacts on the development of social behaviors. Here, we examine the epigenetic and transcriptomic consequences of oxytocin exposure during birth in juvenile male offspring. First, we show that male offspring exposed to oxytocin at birth have increased epigenetic age compared to the saline exposed group. We also find 900 differentially methylated CpG sites (annotated to 589 genes), with 2 CpG sites (2 genes) remaining significant after correction for multiple comparisons. Differentially methylated CpG sites are involved in regulation of gene expression and neurodevelopment. Using RNA-sequencing we find 217 nominally differentially expressed genes (p<0.05) in nucleus accumbens, a brain region involved in reward circuitry and social behavior, including 6 genes that remain significantly differentially expressed after corrections for multiple comparisons. Finally, we show that maternal oxytocin administration leads to widespread alternative splicing in the nucleus accumbens. These results indicate that oxytocin exposure during birth has long lasting epigenetic consequences in the brain and warrant further investigation of how oxytocin administration impacts development and behavior throughout the lifespan.
Project description:Parallel processing circuits are thought to dramatically expand the network capabilities of the nervous system. Magnocellular and parvocellular oxytocin neurons have been proposed to subserve two parallel streams of social information processing, which allow a single molecule to encode a diverse array of ethologically distinct behaviors, although to date direct evidence to support this hypothesis is lacking. Here we provide the first comprehensive characterization of magnocellular and parvocellular oxytocin neurons, validated across anatomical, projection target, electrophysiological, and transcriptional criteria. We next used novel multiple feature selection tools in Fmr1 KO mice to provide direct evidence that normal functioning of the parvocellular but not magnocellular oxytocin pathway is required for autism-relevant social reward behavior. Finally, we demonstrate that autism risk genes are uniquely enriched in parvocellular oxytocin neurons. Taken together these results provide the first evidence that oxytocin pathway specific pathogenic mechanisms account for social impairments across a broad range of autism etiologies.
Project description:Rates of oxytocin use to induce or augment labor are increasing in the United States with little understanding of the impact on offspring development. Using a prairie vole animal model, we have shown that oxytocin administered to mothers can reach offspring brains with long lasting impacts on the development of social behaviors. Here, we examine the epigenetic and transcriptomic consequences of oxytocin exposure during birth in juvenile male offspring. First, we show that male offspring exposed to oxytocin at birth have increased epigenetic age compared to the saline exposed group. We also find 900 differentially methylated CpG sites (annotated to 589 genes), with 2 CpG sites (2 genes) remaining significant after correction for multiple comparisons. Differentially methylated CpG sites are involved in regulation of gene expression and neurodevelopment. Using RNA-sequencing we find 217 nominally differentially expressed genes (p<0.05) in nucleus accumbens, a brain region involved in reward circuitry and social behavior, including 6 genes that remain significantly differentially expressed after corrections for multiple comparisons. Finally, we show that maternal oxytocin administration leads to widespread alternative splicing in the nucleus accumbens. These results indicate that oxytocin exposure during birth has long lasting epigenetic consequences in the brain and warrant further investigation of how oxytocin administration impacts development and behavior throughout the lifespan.
Project description:Selective oxytocin receptor activation prevents prefrontal circuit dysfunction and social behavioral alterations in response to chronic prefrontal cortex activation in rats
Project description:Pyramidal neurons in the cortex are embedded in distinct information processing pathways. Cortical layer 5 (L5) intratelencephalic (IT) and pyramidal tract (PT) neurons receive different input and project to distinct brain regions. The synaptic molecular signatures that define synaptic connectivity and function of L5 IT and PT neurons are largely unknown. Here, we use an optimized proximity biotinylation workflow to characterize the excitatory postsynaptic proteomes of L5 IT and PT neurons in intact somatosensory circuits. We find that differential expression of neurotransmitter receptors, ion channels and cell-surface proteins (CSPs), most prominently of the leucine-rich repeat (LRR) family, specifies L5 IT and PT neuron input connectivity and function. Our analysis further uncovers differential vulnerability to neurodevelopmental disorders for L5 IT and PT neurons, with a marked enrichment of autism risk genes in the postsynaptic excitatory proteome of IT, but not of PT, neurons. Together, cell type- and input type-specific synaptic proteome profiling implies that many of the proteins specifying connectivity and function of two closely related cortical pyramidal cell types also underlie their differential vulnerability to neurodevelopmental disorders.