Jeffrey Neul - US grants

[unreadable] DESCRIPTION (provided by applicant): Rett Syndrome (RTT, MIM 312750) is an X-linked neuro-developmental condition characterized by a variety of clinical features, most notably loss of hand use and language between 6-18 months of life. Furthermore, affected individuals have prominent hand stereotypes, growth failure, cognitive impairment, autonomic dysfunction and seizures. RTT is caused by mutations in the gene encoding Methyl-CpG Binding Protein 2 (MECP2). An animal model generated in the laboratory of Dr. Zoghbi recapitulates many of the clinical features of RTT and thus is a useful disease model. Importantly, many of the movement abnormalities seen in the human disease are present in the animal model. This proposal is based on the hypothesis that specific clinical features in RTT are attributable to MeCP2 dysfunction within specific neuron populations. Specifically, MeCP2 dysfunction within the nigrostriatal dopaminergic system is the cause of the movement abnormalities in the disease. Therefore, this proposal seeks to explore the dopaminergic system in an animal model of RTT. The Specific Aims of this grant are to: 1) Characterize the dopaminergic system in RTT mice by studying the neurochemical composition and behavioral response of RTT mice to pharmacological challenge; 2) Determine the consequence of loss of MeCP2 function exclusively in the dopaminergic system; 3) Analyze gene expression changes within pre- and post-synaptic dopamine neurons in the RTT mouse model. These studies will explore the dysfunction of the dopamine system in RTT and will illuminate possible therapeutic strategies for the movement abnormalities found in RTT syndrome. Furthermore, they will shed light on the genetic mechanisms generating movement disorders in general. This insight may pave the way for future therapeutic strategies for other movement disorders such as: Parkinson's disease or Huntington's disease. [unreadable] [unreadable]

DESCRIPTION (provided by applicant): Mutations in the X-linked gene that encodes MeCP2 (MECP2) cause Rett Syndrome (RTT) in girls and severe congenital encephalopathy in boys. Although cognitive impairment and neurological dysfunction are hallmarks of these disorders, affected individuals also have disruption of many autonomic functions. Girls with RTT have highly irregular breathing and abnormalities in cardiac rhythm including prolonged corrected QT interval and decreased beat-to-beat variability. One quarter of deaths in RTT are sudden and unexpected;autonomic abnormalities are believed to underlie their deaths. Boys with mutations in MECP2 and congenital encephalopathy have a number of autonomic abnormalities including bradycardia, apnea, and respiratory arrest resulting in death in the first three years of life. Male mice lacking MeCP2 function (Mecp2null/Y) have shortened lifespan and reproduce many clinical features of RTT including autonomic changes such as breathing abnormalities and long QTc. However, the relationship between the physiological changes observed during the progression towards death remains unknown. We have recently discovered that removing MeCP2 function from distinct anatomical regions can reproduce the premature death seen in Mecp2null/Y animals. These findings lead to the hypothesis that loss of MeCP2 function within specific neuronal populations leads to premature death secondary to autonomic dysfunction. The goal of this work is to determine the physiological changes that precede and lead to death and to identify key anatomical regions in which loss of MeCP2 leads to autonomic dysfunction and death. The specific aims are: 1) Determine the physiological changes in Mecp2null/Y animals. Understanding the temporal relationship of various physiological changes will provide insight into the primary cause of death. 2) Define critical anatomical regions that require MeCP2 function for normal lifespan and physiology using a conditional knock-out approach. This will determine anatomical regions in which MeCP2 function is required for autonomic control;furthermore, elucidation of specific physiological abnormalities that precede or lead to premature death will suggest causality. 3) Identify anatomical regions in which restoring MeCP2 function is able to rescue premature death and improve physiology. The information obtained from this project will work towards an understanding of the underlying causes of death and autonomic dysfunction in humans with MECP2 related disorders. In addition, it will further the understanding and definition of neuronal circuits that control key autonomic functions. This knowledge will not only be useful in developing therapies for RTT and other MECP2 related disorders but will also provide mechanistic understanding that might give insight into other clinical disorders that have alterations in respiration, cardiac function, or autonomic control, such as sudden infant death, congenital hypoventilation syndrome, familial dysautonomia, and multiple system atrophy. PUBLIC HEALTH RELEVANCE: The goal of this project is to understand how abnormal function of the brain affects the activity of the autonomic nervous system and how it leads to premature death in Rett syndrome and other disorders of childhood. This understanding will help us better understand problems which affect the ability of the nervous system to automatically control breathing, heart rate, and other functions of this special part of the nervous system. Knowledge gained from this will assist in the development of treatments not only for Rett syndrome and related disorders, but also for other diseases that affect autonomic functioning and which are significant public health problems such as sudden infant death syndrome, familial dysautonomia, multiple system atrophy (a type of parkinsonism), and congenital central hypoventilation syndrome among others.

DESCRIPTION (provided by applicant): Mutations in the X-linked gene that encodes MeCP2 (MECP2) cause Rett Syndrome (RTT) in girls and severe congenital encephalopathy in boys. Although cognitive impairment and neurological dysfunction are hallmarks of these disorders, affected individuals also have disruption of many autonomic functions. Girls with RTT have highly irregular breathing and abnormalities in cardiac rhythm including prolonged corrected QT interval and decreased beat-to-beat variability. One quarter of deaths in RTT are sudden and unexpected; autonomic abnormalities are believed to underlie their deaths. Boys with mutations in MECP2 and congenital encephalopathy have a number of autonomic abnormalities including bradycardia, apnea, and respiratory arrest resulting in death in the first three years of life. Male mice lacking MeCP2 function (Mecp2null/Y) have shortened lifespan and reproduce many clinical features of RTT including autonomic changes such as breathing abnormalities and long QTc. However, the relationship between the physiological changes observed during the progression towards death remains unknown. We have recently discovered that removing MeCP2 function from distinct anatomical regions can reproduce the premature death seen in Mecp2null/Y animals. These findings lead to the hypothesis that loss of MeCP2 function within specific neuronal populations leads to premature death secondary to autonomic dysfunction. The goal of this work is to determine the physiological changes that precede and lead to death and to identify key anatomical regions in which loss of MeCP2 leads to autonomic dysfunction and death. The specific aims are: 1) Determine the physiological changes in Mecp2null/Y animals. Understanding the temporal relationship of various physiological changes will provide insight into the primary cause of death. 2) Define critical anatomical regions that require MeCP2 function for normal lifespan and physiology using a conditional knock-out approach. This will determine anatomical regions in which MeCP2 function is required for autonomic control; furthermore, elucidation of specific physiological abnormalities that precede or lead to premature death will suggest causality. 3) Identify anatomical regions in which restoring MeCP2 function is able to rescue premature death and improve physiology. The information obtained from this project will work towards an understanding of the underlying causes of death and autonomic dysfunction in humans with MECP2 related disorders. In addition, it will further the understanding and definition of neuronal circuits that control key autonomic functions. This knowledge will not only be useful in developing therapies for RTT and other MECP2 related disorders but will also provide mechanistic understanding that might give insight into other clinical disorders that have alterations in respiration, cardiac function, or autonomic control, such as sudden infant death, congenital hypoventilation syndrome, familial dysautonomia, and multiple system atrophy. PUBLIC HEALTH RELEVANCE: The goal of this project is to understand how abnormal function of the brain affects the activity of the autonomic nervous system and how it leads to premature death in Rett syndrome and other disorders of childhood. This understanding will help us better understand problems which affect the ability of the nervous system to automatically control breathing, heart rate, and other functions of this special part of the nervous system. Knowledge gained from this will assist in the development of treatments not only for Rett syndrome and related disorders, but also for other diseases that affect autonomic functioning and which are significant public health problems such as sudden infant death syndrome, familial dysautonomia, multiple system atrophy (a type of parkinsonism), and congenital central hypoventilation syndrome among others.

DESCRIPTION (provided by applicant): Mutations in the X-linked gene that encodes MeCP2 (MECP2) cause Rett Syndrome (RTT) in girls and severe congenital encephalopathy in boys. Although cognitive impairment and neurological dysfunction are hallmarks of these disorders, affected individuals also have disruption of many autonomic functions. Girls with RTT have highly irregular breathing and abnormalities in cardiac rhythm including prolonged corrected QT interval and decreased beat-to-beat variability. One quarter of deaths in RTT are sudden and unexpected; autonomic abnormalities are believed to underlie their deaths. Boys with mutations in MECP2 and congenital encephalopathy have a number of autonomic abnormalities including bradycardia, apnea, and respiratory arrest resulting in death in the first three years of life. Male mice lacking MeCP2 function (Mecp2null/Y) have shortened lifespan and reproduce many clinical features of RTT including autonomic changes such as breathing abnormalities and long QTc. However, the relationship between the physiological changes observed during the progression towards death remains unknown. We have recently discovered that removing MeCP2 function from distinct anatomical regions can reproduce the premature death seen in Mecp2null/Y animals. These findings lead to the hypothesis that loss of MeCP2 function within specific neuronal populations leads to premature death secondary to autonomic dysfunction. The goal of this work is to determine the physiological changes that precede and lead to death and to identify key anatomical regions in which loss of MeCP2 leads to autonomic dysfunction and death. The specific aims are: 1) Determine the physiological changes in Mecp2null/Y animals. Understanding the temporal relationship of various physiological changes will provide insight into the primary cause of death. 2) Define critical anatomical regions that require MeCP2 function for normal lifespan and physiology using a conditional knock-out approach. This will determine anatomical regions in which MeCP2 function is required for autonomic control; furthermore, elucidation of specific physiological abnormalities that precede or lead to premature death will suggest causality. 3) Identify anatomical regions in which restoring MeCP2 function is able to rescue premature death and improve physiology. The information obtained from this project will work towards an understanding of the underlying causes of death and autonomic dysfunction in humans with MECP2 related disorders. In addition, it will further the understanding and definition of neuronal circuits that control key autonomic functions. This knowledge will not only be useful in developing therapies for RTT and other MECP2 related disorders but will also provide mechanistic understanding that might give insight into other clinical disorders that have alterations in respiration, cardiac function, or autonomic control, such as sudden infant death, congenital hypoventilation syndrome, familial dysautonomia, and multiple system atrophy.

? DESCRIPTION (provided by applicant): The Baylor College of Medicine Intellectual and Developmental Disabilities Research Center (BCM IDDRC) was established August 1, 1988, and has been continuously funded with the last renewal of funding July 1, 2009. The BCM IDDRC is committed to advancing research in intellectual and developmental disabilities (IDD) to address the problems encountered by individuals with IDD and their families. Specifically, the mission of the BCM IDDRC are to identify as many causes of intellectual and developmental disability as possible, to understand the mechanisms mediating these disorders, to prevent these disorders, and to provide interventions that can improve the quality of life of affected individuals and ameliorate their disability whenever possible. The specific objectives are: 1) To enhance IDD research activities at BCM by encouraging and focusing research efforts on etiology, diagnosis, prevention, mechanism of pathogenesis, and the development of therapies to treat IDD, 2) To develop and provide innovative and critical core facilities to enhance IDD research at BCM, 3) To promote a multidisciplinary approach to IDD research by improving interactions between Center investigators and recruiting new investigators into the field of IDD research, and 4) To promote scientific and collaborative interactions with investigators outside BCM who have demonstrated a major commitment to study and treat IDD. The BCM IDDRC is structured around the major themes of discovering the genetic and genomic basis of IDD, developing disease models of IDD, performing detailed pathogenesis studies of IDD, and developing novel therapies for IDD. The mission and goals of the BCM IDDRC will be accomplished by providing innovative, important, and cost-effective research core services to support high quality investigators and research projects aligned with the mission, goals, and objectives of the IDDRC. The BCM IDDRC proposes A) an Administrative Core, B) a Clinical Translational Core, C) a Rodent Neurobehavioral Core, D) a Neurovisualization Core which includes Neuropathology, Confocal, and RNA in situ, and (E) a Neuroconnectivity Core which includes Viral Production, Optogenetics, and In vivo Physiology. Additionally, the BCM IDDRC will support an innovative preclinical research project entitled Steps towards a paternal gene activation therapy for Angelman syndrome that will develop novel, genetically based treatments for that neurodevelopmental disorder. These core resources will support 45 investigators and 56 NIH funded research projects. Over the last 25 years the BCM IDDRC has been remarkably successful in fostering the discovery of the causes of IDD, determining the pathophysiology of IDD, and developing treatments for IDD. Ongoing funding will allow the Center to continue to support and expand these efforts at BCM.

Achievement; Adherence; Advisory Committees; Animal Model; Area; base; Basic Science; bench to bedside; biobank; Biological; Biological Markers; biomarker discovery; Clinic; Clinical; Clinical Investigator; Clinical Research; Clinical Trials Unit; Collaborations; Collection; college; cost effectiveness; Coupled; Data Quality; Diagnosis; driving force; Environment; experience; Generations; Genes; Genetic; Genomics; Good Clinical Practice; Human; Human Subject Research; improved; Infrastructure; insight; Institutes; Intellectual functioning disability; Laboratories; Lesion; Manuscripts; Medicine; Mental Retardation and Developmental Disabilities Research Centers; Mentors; Molecular; Neurodevelopmental Disorder; novel therapeutics; Organization administrative structures; patient biomarkers; Patient Care; Patients; Performance; Phenotype; Positioning Attribute; prevent; Process; Proteomics; Protocols documentation; Publishing; Research; Research Activity; research clinical testing; Research Personnel; research study; Resources; Sampling; Scientist; Services; success; Supervision; System; Techniques; Testing; Time; transcriptomics; Translating; Translational Research; translational scientist; Translations; trial design; Validation;

STRATEGY I. OBJECTIVES OF THE ADMINISTRATIVE CORE The mission of the IDDRC is to enhance IDD research activities at BCM by supporting research on etiology, diagnosis, prevention, pathogenesis, and the development of therapies to treat IDD. Our objectives are to: 1. Support faculty research into IDD through strategic core facilities and develop new core services as fields advance. 2. Strengthen our multidisciplinary approach to IDD research by fostering interactions between Center investigators and recruiting investigators from other fields into the field of IDD research. 3. Facilitate scientific and collaborative interactions with investigators outside Baylor who have demonstrated a major commitment to study and treat IDD. The Administrative Core will continue to meet these objectives by wisely administering funds awarded to the IDDRC, maintaining a high-quality infrastructure to support the research projects, and spurring collaborations amongst investigators at BCM as well with investigators at other institutions. The Administrative Core will also actively seek additional funding for IDD research and will help new investigators find funding opportunities with the most appropriate agencies and foundations for their research projects.

Adolescent; Adult; Age; Alleles; Angelman Syndrome; Animals; Antisense Oligonucleotide Therapy; Antisense Oligonucleotides; Antisense RNA; base; Binding; Biological Markers; Birth; Body Fluids; Brain; brain morphology; candidate marker; Cell model; Cells; Collaborations; CRISPR/Cas technology; Data; design; Development; developmental disease; Diagnosis; Dose; drug development; Evaluation; Fibroblasts; Funding; Gene Activation; Genes; Genetic Transcription; Genomic DNA; Genotype; Goals; Government; Histopathology; Human; imprint; improved; induced pluripotent stem cell; Intellectual functioning disability; knock-down; Measures; Mediating; Mental Retardation and Developmental Disabilities Research Centers; metabolomics; Methods; Molecular Genetics; mouse model; Mus; Mutation; Neuraxis; Neurodevelopmental Disorder; Neurologic Examination; Neurons; Oligonucleotides; optimism; Patients; Persons; Pharmaceutical Preparations; Pharmacologic Substance; Phase I Clinical Trials; Phenotype; Plasma; postnatal; preclinical study; Proteomics; Provider; Research; Route; Schedule; Sequence Homology; Skin; Spinal Muscular Atrophy; Testing; Therapeutic Index; Therapeutic Intervention; therapy development; Time; Tissues; transcriptomics; UBE3A gene; Wild Type Mouse;

Adult; Affect; Anatomy; Architecture; autism spectrum disorder; Behavior; Brain; brain malformation; Cells; Child; college; Data; Defect; Detection; Development; Disease; Drosophila genus; Electrons; Epilepsy; Equipment; experimental analysis; Faculty; Functional disorder; Funding; Gene Expression; Gene Expression Profiling; Genetic Models; Goals; grasp; Hour; Human; human disease; Image; Image Analysis; In Situ Hybridization; in vivo; Individual; innovation; Institutes; Intellectual functioning disability; knowledge base; Label; Laboratories; Lead; Maps; Medicine; Mental Retardation and Developmental Disabilities Research Centers; Microscope; Microscopic; Microscopy; Mission; mRNA Expression; Nerve Degeneration; neural circuit; neural correlate; Neurologic; Neurons; neuropathology; Pattern; Population; Postdoctoral Fellow; Preparation; Process; quantitative imaging; Reporter; Research Institute; Research Personnel; research study; Resolution; Resources; RNA; robot assistance; Role; Science; Services; Signal Transduction; skills; Staining method; Stains; Structure; Students; Synapses; Technology; Time; Tissue Embedding; Tissue Sample; Tissues; Training; translational study; Transmission Electron Microscopy; two-photon; Work;

Animals; Behavior; Behavioral; Brain; brain tissue; Cell Communication; Cell Culture Techniques; cell type; Clinical; cost; cost effective; Custom; Data; Dependovirus; design; Disease model; Engineering; engineering design; Experimental Designs; flexibility; Functional disorder; gain of function; Gene Expression; genetic approach; Genetic Engineering; genetic manipulation; Goals; Image; In Vitro; in vivo; Individual; insight; Intellectual functioning disability; Investigation; Knowledge; Laboratories; Life; Light; Maps; member; Mental Retardation and Developmental Disabilities Research Centers; Methods; Molecular; Molecular Biology; mouse model; Nerve Tissue; nervous system disorder; Nervous System Physiology; neural circuit; neuronal patterning; Neurons; neurophysiology; Neurosciences; neurotropic; neurotropic virus; optogenetics; Pattern; Preparation; Process; Production; programs; Property; Proteins; Reagent; Relative (related person); Reporter; Research; Research Personnel; Rodent Model; Services; Slice; small hairpin RNA; Subfamily lentivirinae; Synapses; synaptic function; Technology; Testing; Time; Tracer; Transgenic Mice; Transgenic Organisms; vector; Viral; Viral Vector; virus genetics;

The objectives of the BCM IDDRC Neurobehavioral Core are three-fold. The first is to provide training in the rigorous performance of mouse behavioral assays. The second goal is to provide priority access to the Neurobehavioral Core facilities for BCM IDDRC investigators interested in identifying and characterizing behavioral abnormalities in mice carrying mutations relevant to IDD. BCM IDDRC investigators will have two options available to them for the behavioral analyses of their mutant mice. Investigators will be able to either test their own mice, or they will be able to utilize core services to perform behavioral analyses for them on a collaborative basis with Dr. Paylor's group for either mutant mice or newly developed mutant rats (1). This latter strategy is referred to as a collaborative core service. The third objective of the Neurobehavioral Core is to provide training in experimental design and statistical analyses that is customized for the mutant mouse behavioral analyses. While the ability of laboratories to use genetic and molecular techniques for generating mutant mouse models of intellectual disabilities has become more routine, the ability to perform comprehensive analyses of the behavioral responses of these mutant mice is still expensive, requires numerous pieces of specialized equipment and specially designed laboratory space. Perhaps most significant, appropriate training in the design of studies and analysis of the resultant data (along with use of the equipment) is necessary to generate high quality and reproducible results. It is the goal of the Neurobehavioral Core to provide access to state of the art facilities that are equipped with specialized equipment for behavioral studies. It also provides rigorous training to ensure successful analysis of mutant mice generated by BCM IDDRC investigators. In addition, a collaborative service is available to those BCM IDDRC investigators interested in having the testing performed for them in collaboration with Dr. Paylor. The collaborative model applies, in particular, to the newly developed rat genetic models that are already being analyzed and are likely to be advanced in the coming years. The BCM IDDRC Neurobehavioral Core will provide BCM IDDRC investigators with a battery of assays that will offer initial insight into the behavioral consequences of specific mutations. In addition, the Neurobehavioral Core will also provide access and training on the use of additional behavioral assays that will allow a BCM IDDRC investigator to perform critical secondary or follow-up studies important to better understand the nature of any behavioral abnormality detected with a primary behavioral test battery. The Neurobehavioral Core of the BCM IDDRC is well established in studying the behavioral responses of mutant mice. The Core has been in operation for more than 15 years, since the original recruitment of Dr. Paylor. Dr. Paylor was involved in the initial studies of behavioral effects in a knockout mouse model in 1991, and has since evaluated the behavioral effects of over 200 different mutations in lines of mice. Most recently, he has characterized 7 mutations resulting in gene knockouts in rats, which are now possible with the use of TALEN and CRISPR methods for generating genetic lesions. Shortly after joining BCM, Dr. Paylor became the Director for the BCM IDDRC Neurobehavioral Core. His laboratory developed and utilizes a comprehensive set of behavioral assays to evaluate a wide range of responses in mutant mice and his skills and experience have been translated to the Neurobehavioral Core. Dr. Corinne Spencer is the Co-Director for the BCM IDDRC Neurobehavioral Core. She joined the Neurobehavioral Core approximately 8 years ago and has quickly become a major strength of the Core by providing management of the day-to-day operation of the Core, training investigators on various items of equipment, the development and validation of new testing assays, and training users in best practices for rigorous and reproducible behavioral studies in the mouse. Users of BCM IDDRC Neurobehavioral Core have access to a wide array of behavioral assays (see below) to assess numerous domains of CNS function. The Core has been incredibly successful during the previous funding period as measured by the number of users, hours of use, and publications by a variety of users. Moreover, the Core continues to expand its ability to assess behavioral responses of mutant mice and now rats, responding to increasing needs and desires of BCM IDDRC investigators.

? DESCRIPTION (provided by applicant): Rett syndrome (RTT) is a severe neurodevelopmental disorder characterized by a wide range of neurological deficits including, seizures, movement disorders, autonomic dysfunction, and marked breathing abnormalities. Nearly all cases of RTT are caused by de novo mutations in Methyl-CpG-binding protein 2 (MECP2), which functions as a global regulator of gene transcription. MeCP2 is highly expressed throughout the nervous system, and because the clinical features are associated with neuronal function, RTT has typically been assumed to be a disease of neurons. However, recent work has challenged this view, indicating that other cells within the nervous system such as astrocytes and microglia may play an important role in the pathogenesis of disease. While astrocytes directly contribute to key phenotypes associated with RTT, such as breathing and glucose sensitivity, the consequences of loss of MeCP2 on specific astrocyte sub-populations in these key regions remains completely undefined. Astrocytes have long been considered to be a uniform cell type, and in spite of recent findings indicating they perform diverse roles across the CNS, the nature of their cellular and functional heterogeneity remains shrouded in mystery. Using the brainstem and RTT as models for decoding these cellular and functional relationships, we hypothesize that MeCP2 plays a crucial role in key astrocyte subtypes within the brainstem, a brain region we have previously demonstrated to be critical in the genesis of breathing and other physiological abnormalities in RTT. To this end we have used FACS-based approaches to identify unique subpopulations of astrocytes in the adult brainstem. In specific aim 1 of this proposal, we will validate the presence of these populations in the brainstem and perform gene expression profiling on each subpopulation to decode their unique molecular signature. In specific aim 2 we will use similar FACS-based approaches to delineate astrocyte heterogeneity and their underlying molecular profiles in the brainstem of the RTT mouse. Through this work we will determine brainstem astrocyte heterogeneity and define the molecular profiles of these cells in normal and MeCP2 mutant populations, lending unprecedented insight into the nature of astrocyte heterogeneity in health and disease.

Rett syndrome (RTT) is a devastating X-linked neurodevelopmental disorder and one of the leading causes of intellectual disability and developmental regression in girls. RTT is caused by loss-of-function mutations in the gene encoding the transcriptional modulator Methyl-CpG-Binding Protein 2 (MeCP2) and several mouse models that recapitulate features of the disease have been created by targeted disruption of the homologous mouse gene, Mecp2. There is a crucial need to develop therapies for RTT, however, the best practices and standards for performing preclinical trials ? which will be essential for prioritizing and validating therapies that are to be advanced to human trials ? have not yet been determined. To address this need, we propose studies in well-chosen RTT rodent models that consider factors such as sex, genetic strain background, species, and age during the natural course of disease. By defining the onset and progression of translationally-relevant neurobehavioral phenotypes and co-occurring plasma metabolite alterations, we will bridge behavioral outcome with potential biomarkers for RTT. In addition, we will use genetic and pharmacological strategies to examine how biomarkers may change with disease improvement to further classify markers that may predict treatment response. Finally, to optimize the clinical relevance of our results, we will test metabolites identified from our animal studies in RTT individuals. Our goal is to identify the phenotypic and biochemical alterations in Mecp2 rodents that can serve as outcome measures in preclinical studies in animal models and eventual clinical studies in humans. We hypothesize that abnormalities in plasma metabolites that co-occur with disease onset, become markedly altered with disease progression and conversely normalized with disease improvement will serve as the most useful biomarkers with the highest degree of translatability. The Specific Aims of the proposal are i) to define and validate translationally-relevant phenotypes and co-occurring changes in plasma metabolites among Mecp2 rodents, ii) to examine alterations in behavior and metabolite profile during disease improvement, and iii) to evaluate the predictive validity of Mecp2 rodent biochemical alterations in RTT. The unique features of the proposed work should maximize its utility to the RTT research community and accelerate preclinical studies in RTT models. Taken together, these studies will provide the indispensable ground-work for endeavors to identify from rodent models the interventions that have the highest likelihood of translating into effective human therapies. Regardless of the outcome, the results will define the direction that the field must take, either underscoring the need for new approaches, or promoting the most effective preclinical research practices using existing rodent models.