Melissa D. Bauman - US grants

[unreadable] DESCRIPTION (provided by applicant): Autism is a neurodevelopmental disorder characterized by deficits in social behavior and communication and the presence of repetitive or stereotyped behaviors. The etiology(ies) of autism are currently unknown. However, evidence suggests that maternal autoantibodies directed against fetal brain tissue are a putative cause for a subset of autism cases. In support of this, we have recently identified a characteristic pattern of autoantibody production to human fetal brain tissue (and to rhesus monkey brain tissue) in 20% of mothers of multiple children with autism. Our preliminary studies indicate that rhesus monkeys, prenatally exposed to IgG class antibodies from these mothers, produce more whole body motor stereotypies (a defining symptom of autism) compared to control monkeys. These preliminary findings, while striking, are based on a small number of treated subjects, a restricted window of exposure to the purified IgG and a relatively limited period of behavioral observations. It is possible that extending the duration of IgG exposure may result in other behavioral abnormalities more indicative of the complete autistic syndrome. We propose to replicate and extend our research on this promising immunological model of autism by increasing the number of experimental subjects and increasing the duration of IgG exposure into the second trimester for a subset of the experimental subjects. We will enhance and extend the behavioral observations of the treated animals and carry out a structural neuroimaging study. We propose first to conduct an extensive behavioral assessment of the subjects during the first two years of development. We will quantitatively analyze the emergence of species typical behaviors in a variety of social contexts and in experiments designed to probe attachment, social dominance, social motivation and fear reactions. These studies will also evaluate the quality of transactional interactions and detect abnormal behaviors such as stereotypies. We will also carry out a detailed longitudinal magnetic resonance imaging (MRI) study to evaluate differences in the time course of brain development. We will focus the MRI analyses on brain regions most commonly implicated in the neuropathology of autism, including the frontal lobes, amygdala and cerebellum and on structures associated with stereotypies such as the basal ganglia. This work represents a promising animal model of autism and may have direct implications for diagnosis, prevention and treatment of this disorder. PUBLIC HEALTH RELEVANCE: Autism spectrum disorders affect 1:150 children in the United State though the cause(s) are unknown. This project is designed to provide additional support for the hypothesis that abnormal maternal autoantibodies may be one cause of autism. If maternal autoantibodies are identified as a risk factor for autism, this finding would quickly lead both to the development of a diagnostic assay for maternal autoantibodies and to the development of therapeutic interventions to diminish this autism risk factor. [unreadable] [unreadable] [unreadable]

DESCRIPTION (provided by applicant): Due to a profound lack of treatment options for neuropsychiatric disease, there is a critical need to facilitate the translation of findings from basic neuroscience to new treatments for patients. Through an in vivo screen conducted in living mice, a biologically active aminopropyl carbazole, designated P7C3, was identified with potent proneurogenic and neuroprotective properties. A multi-year structure-activity-relationship study on this chemical scaffold has enabled optimization of potency and efficacy, while minimizing real and perceived liabilities for drug development. The P7C3 class of molecules stabilizes mitochondrial membrane potential and protects neurons from cell death. Significant protective efficacy of P7C3 and it's more potent and efficacious variant, P7C3A20, has now been demonstrated in animal models of aging, Alzheimer's disease, Parkinson's disease and amyotrophic lateral sclerosis. A new challenge is to provide additional evidence that these compounds could be beneficial to the human brain. An initial step to meet this challenge is to demonstrate that the most effective of these compounds (P7C3A20) has a proneurogenic and/or protective effect in the nonhuman primate brain. Human brain disorders are defined by changes in complex human behaviors (i.e., cognition, emotion etc.), and evaluation of the therapeutic effects of neuroprotective compounds may ultimately benefit from studies in animal species that are more closely related to humans than are mice. Moreover, the literature is replete with examples of drugs that work well in mice but are not therapeutically beneficial in humans. Rhesus macaques (Macaca mulatta) provide a useful proxy for efficacy in the human, as they demonstrate many features of human physiology, anatomy and behavior. Rhesus monkeys are thus ideal for studying a variety of complex human brain disorders. However, before we can begin to explore the therapeutic potential of the P7C3 class of molecules in sophisticated nonhuman primate diseases models, we must first establish a neuroprotective role for the P7C3 class of molecules in the primate brain. Here, we propose quantification of nonhuman primate hippocampal neurogenesis as a function of exposure to P7C3A20, in order to provide a rapid, cost effective and straightforward means of assessing efficacy of neuroprotection in the rhesus monkey. Preclinical proof of principle in a nonhuman primate could provide an opportunity to translate basic science into a new therapeutic approach for patients suffering from both neuropsychiatric and neurodegenerative diseases involving diminished hippocampal neurogenesis and/or broader neurodegeneration. PUBLIC HEALTH RELEVANCE: This project is designed to provide additional support for a novel class of molecules demonstrating neuroprotective effects in rodent models. Preclinical proof of principle in a nonhuman primate model could provide an opportunity to translate basic science into a new therapeutic approach for patients suffering from both neuropsychiatric and neurodegenerative diseases involving diminished hippocampal neurogenesis and/or broader neurodegeneration.

DESCRIPTION (provided by applicant): The goal of the proposed short-term career award is to provide the applicant with formal training in the behavioral manifestations of early psychosis, which in turn, will advance the translational potential of the applicant's research utilizing anima models of schizophrenia. The proposed training includes regular meetings with mentors, coursework in schizophrenia, a mentor-guided literature review and attending schizophrenia- focused workshops and/or conferences. A critical component of the training plan is direct experience working with individuals at the early stages of the disorder, observation of diagnostic procedures and formal training on the administration of structured clinical interviews. In addition the proposed mentored-research plan will integrate standardized behavioral questionnaires and eye-tracking methodology to evaluate reciprocal social behavior and processing of salient social information in individuals with early psychosis. The research project will provide the applicant with a unique understanding of the challenges involved in evaluating social dysfunction in first episode and ultra-high risk individuals, tools that can be later adapted for use in future animal model studies. UC Davis is an ideal location for the implementation of this proposal, as it provides a rich research environment with strengths in clinical brain research and basic neuroscience, as well as access to an established early psychosis patient population. Successful completion of the proposed training and research plans will provide the applicant with the knowledge and skills to develop increasingly sophisticated animal models of neurodevelopmental disorders and provide the opportunity to establish an ongoing collaboration between animal models and clinical investigations of early psychosis.

SUMMARY: NONHUMAN PRIMATE CORE There is a critical unmet need to develop increasingly sophisticated animal models that will provide insights in the brain mechanisms that may underlie the development of schizophrenia (SZ) and inform the development of novel therapeutic interventions for this illness. While the underlying causes of the illness remain unknown, converging evidence suggests that SZ is a neurodevelopmental brain disease resulting from a combination of genetic and environmental risk factors. Our group is using cross-species, complimentary approaches to examine one potential etiology of SZ ? changes in the prenatal immune environment that alter brain and behavioral development of the offspring. Evidence from epidemiological studies has shown that exposure to a variety of infections during pregnancy is associated with an increased risk of having a child later develop SZ. Rodent models have played a critical role in establishing causal relationships between the activated maternal immune system and aberrant brain and behavior development in the offspring. The long term objective of the Nonhuman Primate (NHP) Core is to bridge the gap between human studies and rodent models, and evaluate the disease relevance of maternal immune activation (MIA) in a model system more closely related to humans ? the rhesus monkey. To accomplish this objective, we will undertake three specific aims. First the NHP core will sample and distribute archived brain tissue from an initial cohort of rhesus monkeys prenatally exposed to MIA to Projects 1 and 2 to evaluate the cellular and molecular pathology underlying aberrant behaviors of MIA offspring. Second, the NHP core will generate a new cohort of MIA and control macaque offspring needed to carry out a highly integrated series of structural, functional and molecular neuroimaging studies in Projects 3 and 4. Finally, the NHP core will conduct a comprehensive assessment of the behavioral development of the new cohort of MIA and control macaque offspring using novel measures that probe the core features of SZ. This interconnected evaluation of brain and behavioral development of monkeys prenatally exposed to MIA will provide further support for an animal model of SZ with high construct, face and predictive reliability. By accomplishing these aims the NHP core will contribute important new insights into the effects of MIA and the mechanisms by which it may contribute to the pathophysiology of SZ. If successful this will lead to the development of novel targets for the development of diagnostic biomarkers and innovative treatments for SZ and other neurodevelopmental disorders.

DESCRIPTION (provided by applicant): While intensive behavioral intervention delivered early in life improves social functioning for some children with autism spectrum disorder (ASD), current pharmacological treatments are limited to targeting only peripheral symptoms such as aggression, anxiety, and depression. Novel pharmacological interventions specifically targeting social behavior delivered in parallel with behavioral intervention holds the promise of improving quality of life for many individuals with ASD. Development of pro-social pharmacological treatments will depend upon the successful translation of basic neuroscience research into safe and effective medicines and will require the use of sophisticated animal models. While current ASD drug discovery efforts have relied primarily upon mouse models to evaluate compound efficacy, pharmacological interventions targeting the complex social and communication deficits of ASD may ultimately require the use of an animal model more closely related to humans. Rhesus monkeys are considered the biomedical model species of choice due to their resemblance in human physiology, neuroanatomy and behavior. Although there are currently no validated nonhuman primate models of ASD, we believe that natural variation in sociability of rhesus monkeys provides a novel model to evaluate the efficacy of pro-social pharmacological treatments. We have established behavioral phenotyping protocols to identify low-social and high-social juvenile monkeys in their natal field cages and to reliably quantify changes in social functioning in a laboratory setting. Our battery of behavioral assays can be used to directly compare social outcome measures with both mouse models (i.e., high-throughput assays of sociability) and clinical populations (i.e., non-invasive eye tracking). With these developments, the nonhuman primate model is poised to provide a valuable test bed for evaluating innovative treatments targeting the core social deficits of ASD. We propose to first utilize this model to evaluate one of the most promising avenues of ASD treatment research - the oxytocin system. Although nasal oxytocin therapy is being promoted as a safe and promising therapy for ASD, we know very little about the efficacy or mechanism of oxytocin treatment in humans. Here we propose to utilize a well-characterized population of juvenile macaque monkeys to systematically evaluate the effects of intranasal oxytocin administration on primate sociability. We anticipate that the methods developed in the proposed research will result in a standard nonhuman primate testing platform that can be used to evaluate numerous future pharmacological interventions targeting the social deficits of ASD.

Maternal infection during pregnancy has emerged from epidemiological research as a key factor in the risk for neurodevelopmental disorders (NDD), including schizophrenia (SZ) and autism spectrum disorder (ASD). Translational animal models demonstrate that maternal immune activation (MIA) negatively affects fetal neurodevelopment and leads to the emergence of aberrant behavior later in life. Emerging evidence from rodent MIA models suggests that prenatal immune challenge induces NDD-like phenotypes not only in exposed individuals but also their descendants, suggesting that the risks of MIA may be exponentially greater than previously understood. Although epigenomic mechanisms could explain both lifetime and transgenerational effects associated with maternal infection, there are limitations in translating epigenetic findings from preclinical rodent MIA models to humans. Our research program has extended the MIA model from rodents to nonhuman primates, demonstrating that rhesus monkeys born the MIA-treated dams exhibit alterations in behavior, immune function, and neural development. Here we propose to leverage the current UC Davis Conte Center funded cohort of MIA exposed nonhuman primates to evaluate, for the first time, the effects of MIA on the primate?s epigenome. This cohort also provides an unprecedented opportunity to explore the potential transgenerational effects of MIA described in rodent models in a species more closely related to humans. We propose to examine the immune cell and germ-line epigenome in MIA-exposed and CONTROL males as they mature from adolescence into early adulthood. We will determine if these changes explain adverse neurobehavioral development in the exposed generation and also confer risk for transgenerational inheritance of MIA effects. Converging evidence from clinical and preclinical studies suggests that the epigenetic and transgenerational mechanisms explored in the proposed studies may be relevant to a number of NDDs independent of current diagnostic classifications. Thus the proposed studies may provide insight into the molecular mechanisms that link prenatal immune challenge to long-lasting brain and behavior abnormalities that are relevant to a number of human brain disorders associated with prenatal environmental insults.

PROJECT SUMMARY / ABSTRACT Autism spectrum disorder (ASD) affects over 1% of children in the United States, yet there remains relatively little understanding of underlying cause(s) and few options for therapeutic interventions. Our research team is evaluating an immune-based mechanism implicated in ASD ? prenatal exposure to maternal autoantibodies that target proteins in the developing fetal brain. A subset of mothers who have a child with ASD produce antibodies to fetal brain proteins that are critical for neurodevelopment, raising the possibility that these antibodies cross the placenta during gestation, interact with fetal brain protein targets, alter neurodevelopment, and lead to a maternal autoantibody related (MAR) form of ASD. We previously developed a passive transfer nonhuman primate model to determine if prenatal exposure to these autism-related autoantibodies alters offspring brain and behavioral development. Although this initial nonhuman primate model yielded promising results, the passive transfer approach relies on periodic injections of the autoantibodies into the pregnant dam and does not reflect a constant exposure throughout gestation, as is likely the case for a human fetus. We therefore initiated a new line of research to generate continuous autoantibody exposure rodent models that are reactive to the targeted epitope sequences specific to MAR risk for ASD, thus mimicking the human autoantibody profile. Rodent offspring continuously exposed to these antibodies during gestation demonstrate deficits in social development and repetitive behaviors paired with aberrant brain development. Our collaborative research team is now positioned to apply the techniques developed and tested in both the mouse and rat models to establish the first biologically relevant rhesus monkey model that will maintain a continuous exposure of autism-related autoantibodies prenatally. This will be accomplished through the following Specific Aims: (1) Develop the first nonhuman primate model to continuously produce anti-fetal brain antibodies throughout gestation and (2) Characterize the biodistribution of fetal brain-specific maternal autoantibodies in fetal rhesus monkeys at multiple time points during gestation. Establishing the nonhuman primate model will allow us to expand the period of in utero autoantibody exposure into the third trimester and provides an opportunity to evaluate the neurobiological effects in brain regions, such as prefrontal cortex, which are not well developed in rodents. At the conclusion of these studies, we will be well-positioned to utilize this sophisticated nonhuman primate model system to determine the mechanism by which prenatal exposure to maternal autoantibodies disrupts fetal brain development and explore, for the first time, therapeutic interventions to mitigate the effects of exposure.

The amygdala has been implicated in nearly every neurodevelopmental and neuropsychiatric disorder, from autism to depression to schizophrenia, and likely contributes to socioemotional deficits that characterize these disorders. Although the causal mechanisms of these disorders remain unknown, a growing body of evidence suggests that maternal factors in utero may influence disease susceptibility. Indeed, children who were prenatally exposed to maternal infection have an increased risk for developing autism, schizophrenia or other neurodevelopmental disorders. Because the genetic, ecological, and behavioral diversity of humans is so remarkably heterogeneous, animal models are essential for testing causality, identifying molecular mechanisms, and developing new diagnostic tools and therapeutics. Maternal immune activation (MIA) models in rodents have demonstrated a causal relationship between maternal response to infection and neuropathological and behavioral abnormalities consistent with a range of neurodevelopmental and psychiatric disorders. However, it was not known if prenatal immune challenge in primates would lead to similar outcomes. To address this major gap, we created a nonhuman primate MIA model of rhesus macaques prenatally exposed to immune challenge. This unprecedented nonhuman primate cohort has undergone extensive behavioral, immune, and neuroimaging studies, and is now being used to evaluate genomic and cellular alterations. We have found that MIA-exposed nonhuman primate offspring show biological and behavioral changes that mimic human psychiatric disease, including amygdala-relevant alterations in socioemotional development. In this proposal, we will utilize the archived brain tissue from this cohort and to evaluate, for the first time, how cellular and molecular mechanisms are altered in the amygdala following prenatal immune challenge. The first step in this pilot proposal is to ask: Is the molecular signature of the amygdala altered in nonhuman primate offspring prenatally exposed to a maternal immune system challenge? To address this question, we will utilize next generation sequencing methods (RNA-seq) to measure genome-wide transcriptome changes as well as weighted-genome co-expression network analysis (WGCNA), a powerful unsupervised systems-biology framework, to identify co-expression modules within and across amygdala nuclei in MIA-exposed animals relative to controls. These modules will be integrated with behavioral, immunologic, and neuroimaging results from the same cohort to identity putative molecular drivers of observed phenotypic alterations following MIA exposure.