Sheryl Moy - US grants

DESCRIPTION (provided by applicant): Schizophrenia, a particularly disabling psychiatric disorder, has been linked to early brain insult, altered neurodevelopment, and an intrinsic hypofunction of NMDA receptor neurotransmission. Researchers have proposed that treatment with antipsychotic drugs, initiated in the early stages of the disease, might slow or halt pathological brain changes in schizophrenia. We have developed a mouse model, the NMDA receptor hypomorphic (NR1-/-) mouse, for the intrinsic deficits in NMDA receptor function that may underlie symptoms in schizophrenia. This model has a behavioral phenotype that reflects alterations observed in the clinical disorder, including deficits in habituation and impaired sensorimotor gating in tests of prepulse inhibition. In addition, NR1-/- mice exhibit low levels of social preference and profound alterations in direct social interaction. Schizophrenia patients also exhibit deficits in social interaction and communication, sometimes well before the emergence of other signs of the disorder. Drugs used for treatment in schizophrenia are most effective against the overt, positive disease symptoms, and less efficacious against negative symptoms, including social withdrawal and anhedonia. The NR1-/- mouse provides a unique system for determining specific drug efficacy against recalcitrant negative symptoms and against disease progression, and for exploring neural mechanisms for behavioral deficits. The first goal of the following studies is to investigate the developmental time course for the emergence of aberrant behaviors, including impairments in social responses, sensorimotor gating, and habituation. The second goal of the proposal is to map the specific brain regions mediating the abnormal social responses characteristic of the NR1-/- mice. For this goal, measures of Fos and FosB immunoreactivity will be used to determine neuronal activation in specific regions in brain. A third goal is to evaluate whether chronic treatment with olanzapine or risperidone, initiated in the post- weanling period, will delay or prevent the deficits in social behavior, sensorimotor gating, and habituation observed in the hypomorphic mice. Results will be compared with chronic haloperidol treatment, to determine if the atypical drugs have differential efficacy against changes in the NR1 hypomorphic mice. For the final goal, Fos and FosB expression will be used to determine the effects of early intervention with antipsychotics on aberrant neuronal activity across multiple regions in brain. Overall, these studies will elucidate the neurodevelopment effects of intrinsic NMDA receptor hypofunction on behavior and regional brain activity, as possible underlying mechanisms and potential targets for therapeutic intervention in schizophrenia. PUBLIC HEALTH RELEVANCE: Schizophrenia is a severe neuropsychiatric syndrome, usually first diagnosed in late adolescence or early adulthood. We have developed a genetic mouse model, the NR1 hypomorphic mouse, for deficient glutamate function relevant to schizophrenia. This proposal would determine the time course in development for the onset of abnormal behavior in the mouse model, and examine whether treatment with antipsychotic drugs, initiated in adolescence, could have beneficial effects on behavior and brain activity in the NR1 hypomorphic mice.

DESCRIPTION (provided by applicant): We have recently identified repetitive motor behaviors in the inbred C58/J mouse strain. This strain robustly displays repetitive behaviors such as jumping, flipping and weaving. The C58/J mouse strain is unique among currently used animal models for restrictive, repetitive behaviors (RRB) because these aberrant behaviors emerge spontaneously during the pre-weaning period and do not require pharmacological insult or environmental restriction, such as isolate-housing, as a trigger. In addition, C58/J is genotypically and phenotypically very similar to C57BL/6J, allowing this commonly used inbred strain to serve as an appropriate control. These characteristics make the C58/J mouse strain a potentially powerful animal model in the study of RRB. In order to further characterize the C58/J mouse strain as a model for RRB in humans, we will use a cross-fostering procedure to establish whether maternal behavior contributes to the emergence of RRB. Additionally, we will determine the efficacy of chronic pharmacological intervention on stereotyped responses in adult C58/J mice. Lastly, we will determine whether aberrant RRB is associated with structural changes in brain, using magnetic resonance imaging. At the present time, there are no well- validated animal models of RBB, a core feature of autism. This project will positively impact the field of autism spectrum disorder research by providing information on the neurobiology of aberrant behaviors in mice and by identifying whether the C58/J inbred strain is indeed an appropriate pre-clinical screen for human RRB, as well as strengthening the emerging field of brain structural imaging in rodents. PUBLIC HEALTH RELEVANCE: The proposed studies will evaluate the C58/J inbred mouse strain as a novel animal model for the study of restricted, repetitive behaviors relevant to autism. The aims will determine whether maternal behavior contributes to the emergence of repetitive behaviors during the neonatal or post-weaning period, and evaluate the efficacy of pharmacological agents against repetitive behaviors in adult C58/J mice. The final goal is to identify structural differences in the brains of C58/J mice using MRI technology.

Preclinical Core Abstract The Preclinical Core (PC) provides IDDRC investigators with innovative, advanced approaches to conduct research spanning fine-grained resolution at the molecular and cellular level, to regional neurocircuitry and connectivity across brain, to multi-domain characterization of mouse behavior. In this application, 40 projects from 21 IDDRC investigators are proposed for core access in studies using models of ADHD, Angelman syndrome, ASD, childhood ataxia, epilepsy, intellectual disability, Joubert syndrome, Pitt-Hopkins syndrome, Rett syndrome, and other neurodevelopmental disorders. The PC has three components, the Mouse Behavioral Phenotyping Laboratory, the Neuroscience Microscopy Facility, and the Small Animal Imaging Service, which, together, offer a broad range of resources and expertise for multidisciplinary IDD research. Services include consultation with expert core faculty, an extensive battery of mouse behavioral testing, training in cutting-edge microscopy methods, acquisition and analysis of quantitative MRI data, and access to state-of-the-art laboratory facilities. A critical goal for the Core is to facilitate projects integrating complementary approaches, such as microscopy analysis of cortical architecture and behavioral evaluation of cognitive phenotypes, to enhance understanding of underlying pathophysiology and structure-function relationships in neurodevelopmental disorders. Within the IDDRC, the PC partners with the Clinical Translational Core and Data Science Core around the use of machine-learning approaches and the establishment of automated data-processing pipelines for new methods development. Overall, the PC provides expertise and infrastructure that has become essential for our IDDRC research using preclinical models, with the overarching aim of supporting breakthrough, transformative science in diagnosis, prevention, and treatment of developmental disorders. 1

The autism spectrum disorders (ASDs) are a heterogeneous group of developmental disorders with specific core features, including impaired social interaction and abnormal repetitive behavior. Several ongoing studies, including our own, are assessing the use of the drug oxytocin to ameliorate social deficits in individuals with ASDs and other psychosocial disorders. We hypothesize that behavioral response to oxytocin treatment is mediated by genetic and epigenetic factors and that these factors, particularly epigenetic mediators of gene expression, may be pivotal to baseline response and/or may change during oxytocin exposure. This proposal will explore the role of the epigenome and genetic predisposition to oxytocin treatment response in longitudinal samples that have already been collected as part of an ongoing clinical trial in high and low functioning children with ASDs; we will investigate the transcriptome and epigenome (5mC and 5hmC) in regions of the brain and periphery of a mouse model of ASD known to have positive response to oxytocin treatment; we will also examine novel regulatory mechanisms of oxytocin's receptor OXTR via 5-hydroxy methyl cytosine. The data generated by these aims will not only serve to develop (epi)genetic predictors of oxytocin response, but they will inform other trials using oxytocin to treat psychosocial disorders.