Moses V. Chao - US grants

DESCRIPTION: Neuronal cell survival is dependent upon many trophic influences, of which nerve growth factor (NGF) has been the most extensively studied and understood. The long term goal of this grant proposal is to understand the molecular mechanism of nerve cell survival. The NGF family includes brain derived neurotrophic factor and neurotrophins_3 and NT_4/5. Each of these proteins interacts with two different transmembrane receptors, members of the trk tyrosine kinase subfamily and the p75 neurotrophin receptor, a member of the TNF family of receptors. The actions of these receptors determine neuronal cell numbers during development. Co_expression of p75 with trk family members may play a number of crucial functions, including increasing the affinity of ligand binding when trophic factors are present only in limiting concentrations; regulation of tyrosine kinase activity; and greater discrimination between different neurotrophin factors. Additionally, novel signaling pathways utilizing sphingolipid turnover are used by neurotrophins and cytokines as another potential signal transduction mechanism to mediate apoptosis. Selectivity of neurotrophin action is likely to depend upon adual receptor system in which coexpression of trk family members with p75 result in distinctive downstream biological responses. This proposal will focus upon the receptor binding and signaling requirements for NGF. The investigation has implications for mechanisms of cell survival, differentiation and cell death of neuronal cell populations, which will ultimately bear upon our understanding of many neurodegenerative diseases, such as motor neuron and Alzheimer's dementia.

Tumor necrosis factor (TNF-alpha) represents a family of cytokines which induce a wide number of biological effects that directly influence cell growth, cell differentiation, and programmed cell death. The prototype molecule TNF-alpha, is known to be involved in different pathological conditions including septic shock, rheumatoid arthritis, autoimmunity, HIV gene expression, cachexia, and cytotoxicity. Although the actions of TNF- alpha are mediated by two different cell surface receptors of M/r 55,000 and 75,000 daltons, little is known about how these receptors carry out signal transduction. Other growth factor and cytosine families convey their signals across the cell membrane by stimulating specific phosphorylation events after ligand binding. The two TNF receptors form a structurally related family that includes the Fas antigen, CD27, CD30, CD40 and OX40. The grant will test the hypothesis that TNF-alpha action requires additional signaling molecules, which are likely to interact either directly or indirectly with the TNF receptors. These activities may include tyrosine phosphorylation and hydrolysis of sphingomyelin to ceramide. Recent evidence indicates ceramide may act as a second messenger to promote programmed cell death by the TNT-alpha family of cytokines. This proposal will clone the mammalian sphingomyelinase enzyme that is believed to be responsible for TNF signal transduction and identify how ligand binding to this family of receptors leads to the activation of the sphingomyelinase activity. These studies will ultimately elucidate the molecular mechanisms that are responsible for TNF-alpha action during normal and disease states.

This application is for a new training program in the mechanisms of signal transduction in the nervous system at New York University Medical Center. The training faculty include fifteen distinguished scientists representing the Departments of Physiology and Neuroscience, Pharmacology, Microbiology Biochemistry and Cell Biology. The research interests of the program faculty encompass a broad range of fields, including growth factors, cytokines, chemokines, neurotrophic factors and the mechanisms by which extracellular and intracellular signals are transduced; cell adhesion molecules that influence neuronal axonal pathfinding and process outgrowth; selection of synaptic targets; ion channel function; and processes that lead to axonal-glial cell communication. The purpose of this program is to foster the training of graduate students and postdoctoral fellows in basic mechanisms by which neuronal, glial and neuromuscular structure and function are determined. The underlying theme of the program is that cell specification and function in the nervous system are dependent upon ligand-receptor interactions and activation of second messenger pathways. Based upon a record of productive interactions, research collaborations among the trainees and between the participating faculty will be fostered. Trainees will participate in activities including weekly seminars and journal clubs in cellular and developmental neurosciences, journal clubs, and meetings that are designed to provide a broad educational exposure. The emphasis in this training program will be on fundamental biochemical and cellular mechanisms, which are relevant to disorders of the nervous system, including Alzheimer's disease, Parkinson's disease, paralysis, multiple sclerosis and muscular dystrophy.

DESCRIPTION (abstract): The tumor necrosis factor family of cytokines induces a wide number of biological effects that directly influence cell growth, cell differentiation, and apoptosis. A common feature of this family is the existence of transmembrane receptors with multiple conserved cysteine-rich motifs in the ligand binding domain and a short cytoplasmic domain. The TNF receptor superfamily includes the Fas antigen, two TNF receptors, CD40, CD30, and the p 75 neurotrophin receptor. Several of these receptors contain a death domain sequence which is responsible for transmitting cell death signals. These receptors contain a death domain sequence which is responsible for transmitting cell death signals. These receptors can recruit and bind adapter molecules, which in turn associate with cytoplasmic proteins associated with caspase activation and serine/threonine protein kinases activities. In this renewal application, we will focus on an adapter molecule, SC-1, a novel zinc finger protein which belongs to a family of genes implicated in tumor progression. SC-1 was first identified as a p75 receptor binding protein; subsequent studies indicate that it is associated with growth arrest events. The further characterization of this zinc finger protein with the actions of TNF receptor members will likely yield additional mechanisms concerning cell proliferation. These studies will provide insight into mechanisms responsible for cytokine actions during inflammation, injury and disease states.

DESCRIPTION (From the Applicant's Abstract): This application will investigate the mechanisms by which oligodendrocytes progress from a proliferating precursor cell to a fully myelinating cell. It is well established that oligodendrocytes can myelinate multiple axons in the central nervous system. The appearance of oligodendrocytes and their ability to undergo myelination in the CNS occur relatively late during development, after neurogenesis. A number of components of the myelin sheath have been identified, but the underlying molecular mechanisms that control myelin formation and oligodendroglial cells numbers are not fully understood. The specific aims will focus upon the contribution of the cell cycle machinery on the regulation of oligodendrocyte proliferation. In addition, signal transduction events through Fyn tyrosine phosphorylation have been found to be one of the earliest events during oligodendrocyte differentiation. The major objectives will be to define how cell cycle regulation leads to cell specification and how activation of tyrosine kinase activities promotes oligodendrocyte process formation and myelination. These studies may eventually lead to the identification of signals required for oligodendrocytes to form an insulating myelin sheet around axons in the nerve. This investigation will have a direct impact upon basic mechanisms affecting CNS regeneration, remyelination and demyelinating diseases, such as multiple sclerosis.

DESCRIPTION (provided by applicant): The major objectives of this grant have been to identify the signals used by oligodendrocytes and Schwann cells to form a myelin sheet around axons in the nerve. We have taken a new approach to this question by studying the Neuropathy Target Esterase (NTE) or swisscheese gene. Mutations in swisscheese, the Drosophila homolog gene of NTE, indicated swisscheese is involved in the regulation of axon-glial cell interaction during glial wrapping. We have found that loss of NTE function in mice leads to prominent neuronal pathology in the hippocampus and thalamus and also defects in the cerebellum. Absence of NTE resulted in prominent vacuolation of nerve cell bodies, abnormal reticular aggregates and defects in glial wrapping. However, the mechanism of action of NTE/swisscheese in brain function and axon-glial cellular interactions remains unknown, While our past approaches have centered upon cell cycle and tyrosine kinase regulatory events during oligodendrocyte differentiation and myelination, the proposed studies in this grant renewal promise to lead to the mechanisms involved in proper axon-glial cell interactions and neurodegeneration. This investigation will have a direct impact upon basic mechanisms affecting CNS regeneration as well as demyelinating diseases, such as multiple sclerosis. The studies are also relevant to other neurodegenerative diseases characterized by vacuolation and neuronal loss.

[unreadable] DESCRIPTION (provided by applicant): The neurotrophins, NGF, BDNF, NT-3 and NT-4, represent a family of proteins essential for the development of the vertebrate nervous system. In addition to classical effects upon neuronal cell survival, neurotrophins also can regulate axonal and dendritic growth, synaptic structure and connections, neurotransmitter release, long-term potentiation and synaptic plasticity. Each neurotrophin can signal through two different cell surface receptors, Trk receptor tyrosine kinases and the p75 neurotrophin receptor, a member of the TNF receptor superfamily. Given the wide number of activities now associated with neurotrophins, it is likely additional regulatory events and signaling systems are involved. In this application, we will focus on a new and unexpected mechanism. Intramembraneous cleavage of the p75 receptor by gamma-secretase results in the release of the intracellular domain. This is the first known example of this activity in the TNF receptor superfamily. Significantly, the cleavage of p75 has been mapped to the same location as amyloid precursor protein (APR). Cleavage-resistant forms of p75 have been created to test the functional significance of gamma-secretase cleavage and the effect on p75 signaling activities. The functional consequences of p75 cleavage will be tested upon Trk receptor signaling, as well as axonal regeneration events. The p75 receptor is known to interact with cytoplasmic proteins that can translocate to the nucleus. Among many proteins that interact with p75, we will follow SC-1, a novel zinc finger protein that translocates to the nucleus. Since p75 is frequently upregulated after injury, these studies will provide further insight into mechanisms responsible for neurotrophins during inflammation and neurodegenerative disease states, such as Alzheimer's dementia and amyotrophic lateral sclerosis. [unreadable] [unreadable]

[unreadable] DESCRIPTION (provided by applicant): The neurotrophins, NGF, BDNF, NT-3 and NT-4, represent a family of proteins essential for the development of the vertebrate nervous system. In addition to classical effects upon neuronal cell survival, neurotrophins also can regulate axonal and dendritic growth, synaptic structure and connections, neurotransmitter release, long-term potentiation and synaptic plasticity. Each neurotrophin can signal through two different cell surface receptors, Trk receptor tyrosine kinases and the p75 neurotrophin receptor, a member of the TNF receptor superfamily. Given the wide number of activities now associated with neurotrophins, it is likely additional regulatory events and signaling systems are involved. In this application, we will focus on a new and unexpected mechanism. Intramembraneous cleavage of the p75 receptor by gamma-secretase results in the release of the intracellular domain. This is the first known example of this activity in the TNF receptor superfamily. Significantly, the cleavage of p75 has been mapped to the same location as amyloid precursor protein (APR). Cleavage-resistant forms of p75 have been created to test the functional significance of gamma-secretase cleavage and the effect on p75 signaling activities. The functional consequences of p75 cleavage will be tested upon Trk receptor signaling, as well as axonal regeneration events. The p75 receptor is known to interact with cytoplasmic proteins that can translocate to the nucleus. Among many proteins that interact with p75, we will follow SC-1, a novel zinc finger protein that translocates to the nucleus. Since p75 is frequently upregulated after injury, these studies will provide further insight into mechanisms responsible for neurotrophins during inflammation and neurodegenerative disease states, such as Alzheimer's dementia and amyotrophic lateral sclerosis. [unreadable] [unreadable]

[unreadable] DESCRIPTION (provided by applicant): Neurotrophic factors are a class of polypeptide growth factors that influence the proliferation, differentiation, survival and death of neuronal and non-neuronal cells during vertebrate development. During the past decade, it is clear that this group of proteins display remarkable effects upon synaptic transmission and higher order behaviors, such as learning, memory, hyperalgesia and the formation of circuits. Neurotrophic factors exemplified by the NGF family and their receptors are now intensely studied throughout the neurosciences and the clinical disciplines of neurology and psychiatry. The intent of the next International NGF meeting, the Katzir Conference on Life and Death in the Nervous System, is to provide a forum to exchange new results and methodologies in the study of neurotrophic factors. Findings from basic research in this field have relevance to the treatment of neurodegenerative diseases, such as Parkinson's and Alzheimer's diseases, as well as cancer and neuropsychiatric disorders. Support is requested to defray the registration, room and board and travel for the principal speakers and discussion leaders of the meeting. For over twenty years, the International NGF meetings have provided an unparalleled opportunity for scientific exchange between students, postdoctoral fellows, scientists and clinicians. The meetings have been a very effective means of stimulating new research and attracting new scientists to the field. [unreadable] [unreadable] [unreadable]

DESCRIPTION (provided by applicant): Glucocorticoids produced by the adrenal cortex exert many effects in the central nervous system ranging from spatial learning and cognition to stress and depression. Although high levels of glucocorticoids can be detrimental, in moderate concentrations, they can facilitate synaptic plasticity in the hippocampus and neuronal cell survival. The neuroprotective, anti-anxiety, and metabolic effects of glucocorticoids are carried out by the glucocorticoid receptor, which is abundantly expressed in the brain. Interestingly, the effects of glucocorticoids upon neuronal circuits are also strongly influenced by neurotrophins, such as Brain Derived Neurotrophic Factor (BDNF). However, the molecular mechanism of this regulation has not been explored. Recent evidence from our laboratories indicates there is bi-directional signaling between glucocorticoids and neurotrophins. For example, while BDNF signals through a Trk receptor tyrosine kinase, glucocorticoid receptor can bypass the need for BDNF and activate Trk signaling in neuronal cells (Jeanneteau et al PNAS 2008). In a reciprocal interaction, we have recently found that BDNF treatment promotes the phosphorylation of glucocorticoid receptor in neurons at several newly discovered sites. This proposal will dissect the biological consequences of BDNF-dependent phosphorylation of glucocorticoid receptor. Our hypothesis is that by altering phosphorylation, BDNF modulates glucocorticoid receptor gene regulatory functions, which in turn affects hippocampal-pituitary-adrenal (HPA) axis activity. These studies will begin to define the molecular mechanisms that affect feedback control and activity of the HPA system, and provide insight into how glucocorticoids and BDNF influence adaptive and maladaptive actions that are relevant to memory formation, stress response and depression.

Neurotrophins, such as NGF and BDNF, are prominent regulators of neuronal survival, growth and differentiation during development of the vertebrate nervous system. The actions of neurotrophins are dictated by two classes of cell surface receptors, the Trk receptor tyrosine kinases and the p75 neurotrophin receptor. After binding, neurotrophins and each of their receptors undergo internalization, intracellular trafficking and transport. In the last grant period, we studied the activation of Trk receptor tyrosine kinases via a G protein-coupled receptors (GPCR). Two GPCR ligands, adenosine and pituitary adenylate cydaseactivating polypeptide (PACAP), can activate Trk receptor activity to increase the survival of neural cells in the absence of neurotrophins. In contrast to neurotrophin treatment, the majority of activated Trk receptors were found in intracellular locations, such as Golgi and endosomal membranes. These results indicate that intracel lular trafficking of receptors plays an important role in their signaling outcomes. In the next grant period, we will test the hypothesis that proteins that regulate Trk receptor internalization, translocation and recycling are critical to our understanding of neurotrophin signaling. Both the biosynthetic and the endocytic pathways will be examined for their impact on Trk activity. Because the localization of neurotrophin receptors is critical to neuronal cell survival and plasticity, our investigation is directly relevant to the understanding and treatment of neurodegenerative diseases, such as amyotrophic lateral sclerosis, Huntington's and Alzheimer's diseases.

DESCRIPTION (provided by applicant): Neurotrophic factors are potent growth factors that were first characterized for their ability to regulate neuronal growth, survival and differentiation during development. There are many lines of evidence indicating that neurotrophins and the GDNF family, play an important role in the pathophysiology of depression, addiction and other psychiatric disorders, as well as a wide number of neurodegenerative disorders, including amyotrophic lateral sclerosis and Alzheimer's disease. Changes in the levels of BDNF influence hippocampal function, synaptic transmission and learning and memory. Moreover, recent evidence indicates that BDNF is a key component in the etiology of Huntington's and Alzheimer's diseases. During the past decade, it is clear that these proteins display remarkable effects upon synaptic transmission and higher order behavior and the formation of circuits. Neurotrophic factors exemplified by the NGF family and their receptors are now intensely studied throughout the neurosciences and the clinical disciplines of neurology and psychiatry. The intent of the next International NGF meeting in Helsinki, Finland is to provide a forum to exchange new results and methodologies in the study of neurotrophic factors and to bring diverse disciplines of human genetics, cell biology and neuropsychiatry together. Findings from basic research in this field have relevance to the treatment of neurodegenerative diseases, such as Parkinson's and Alzheimer's diseases, as well as cancer and neuropsychiatric disorders. Support is requested to defray the registration, room and board and travel for the principal speakers and discussion leaders of the meeting. PUBLIC HEALTH RELEVANCE: Since 1986, the International NGF meetings have provided an open mechanism for scientific exchange between students, postdoctoral fellows, scientists and clinicians. The meetings have stimulated many new findings, including the discovery of new neurotrophic factors and receptors, and attracted a whole new generation of scientists to the field.

DESCRIPTION (provided by applicant): Neurotrophins, such as NGF and BDNF, are prominent regulators of neuronal survival, growth and differentiation during development of the vertebrate nervous system. They also play an important role in higher order functions, such as pain, addiction, mood disorders and learning and memory. A major problem in the field is to explain how neurotrophins are able to carry out these diverse activities through receptor signaling. The actions of neurotrophins are dictated by two cell surface receptors, Trk tyrosine kinases and the p75 receptor. We are interested in the role of Trk receptor signaling in dictating neuronal responsiveness by neurotrophins. In the next grant period, we will focus upon a multifunctional scaffold protein called ARMS/Kidins220, which is a principal substrate of Trk receptors. This protein is heavily tyrosine phosphorylated by neurotrophins and plays a critical role in the branching of cortical and hippocampal dendrites; in the turnover of cortical spines; and also in modulating basal synaptic transmission. The mechanisms by which ARMS/Kidins220 are involved in neurodegeneration in the entorhinal cortex, as well as receptor tyrosine kinase signaling and interactions with glutamate receptors will be studied. Our investigation is directly relevant to understanding the mechanism of trophic factors and their roles in neurodegenerative diseases, such as amyotrophic lateral sclerosis, Huntington's and Alzheimer's diseases, as well as psychiatric disorders, such as anxiety and depression.

Abstract Oxytocin is a neuropeptide important for social behaviors such as maternal care and parent-infant bonding, however, the exact signaling mechanisms used by oxytocin in the brain are not well understood. The oxytocin receptor is a G protein-coupled receptor that is expressed at two weeks of postnatal life, a time period of heightened plasticity and inhibitory circuit maturation, which is promoted by BDNF. Here we report an interplay between oxytocin and the BDNF TrkB receptor that occurs in the cortex within 15-30 minutes of oxytocin treatment. Receptors for oxytocin and BDNF overlap in their distribution in different brain regions, especially in areas important for learning and memory. Oxytocin's ability to transactivate TrkB receptors is independent of BDNF transcription and release. In the next grant period, we will focus upon the mechanism of TrkB receptor transactivation via oxytocin by studying the cellular mechanisms of action of oxytocin receptors in the rodent brain. We hypothesize that synaptic strength and cortical plasticity may be regulated by the dual actions of oxytocin and TrkB receptor signaling. The long-term effects of oxytocin may be due to crosstalk with the BDNF TrkB receptor. The transactivation of TrkB receptors by oxytocin may affect synaptic changes, and re-balance excitation and inhibition and maintain network stability. Our investigation is directly relevant to understanding the mechanism of trophic factors and their impact upon neurodegenerative diseases, such as amyotrophic lateral sclerosis, Parkinson's, Huntington's and Alzheimer's diseases, as well as neuropsychiatric disorders, such as autism, anxiety, depression and schizophrenia.

Project Summary/Abstract This proposal details the Diverse Neuroscientists: Doctoral Training Series (DeNDriTeS), a new program that will provide mentoring, career planning, and skill training for NYU neuroscience graduate students from diverse backgrounds as they prepare to transition to postdoctoral research positions. Through this new program, we seek to improve the placement of program participants in postdoctoral, and ultimately faculty, positions and, more generally, to prepare participants to excel in their future careers as independent neuroscientists. The program?s aims are to (a) increase mentoring capacity and cultural awareness among our faculty and the broader community; (b) provide enhanced mentoring and directed career planning for diverse students; (c) train students in necessary quantitative and professional skills often overlooked during graduate education; and (d) build community and peer mentoring through a new seminar series, networking receptions, and online platforms. To increase the effectiveness of our faculty mentors, we will run mentor training workshops designed to help program faculty define a mentorship philosophy and to develop better practices for mentoring students from diverse backgrounds. Following this training, faculty mentors will lead bi-monthly meetings for program participants throughout the academic year to supplement existing graduate program mentoring structures. A critical element that promotes retention of diverse students is integration into a strong community of peers. We will develop new opportunities, including a new seminar series and annual networking receptions, for program participants to engage with each other and with program alumni. Finally, an intensive summer workshop series will focus on quantitative, communication, and leadership skills by leveraging existing initiatives and creating new resources. Through this multi-pronged approach, we will engage program faculty and trainees in an ongoing discussion about the importance of mentorship, career planning, networking, and diversity, which will strengthen our program and contribute to a diverse community. New York University and the NYU School of Medicine are devoted to recruiting and training a diverse student body and have many initiatives in place at both campuses. DeNDriTeS will be instrumental in furthering these larger efforts to create a vibrant, interactive and inclusive community. Our program will target advanced predoctoral students, in their 3rd year or higher, who conduct neuroscience research in any graduate program at NYU. New York City is a hub for neuroscience research and diverse cultures, and once the program is well established at NYU we will develop relationships with neighboring institutions to expand the network of scholars who benefit from these mentoring and training opportunities. The inclusion of a broader community of diverse students will have a positive impact upon program participants, as they benefit from expanded connections with many more peers from diverse backgrounds. To evaluate the program?s effectiveness, an advisory board and internal evaluators will work with program leadership to track mentor training, student progress, and participant engagement.

Project Summary: Antibody Core One of the major features of this BRAIN Initative proposal on ?Oxytocin Modulation of Neural Circuit Function and Behavior? is this Oxytocin Receptor Antibody Production Research Support Core. Each of the Project teams is examining oxytocin release and the action of oxytocin receptor signaling. Oxytocin is one of the best- understood modulators at the physiological and behavioral levels, having been studied in various forms for over a century. However, little is known about the cellular and network effects of oxytocin signaling, in part due to previous lack of specific antibodies for determining which brain areas and cell types express oxytocin receptors. Our labs have generated, validated, and are distributing the first specific antibodies to mouse oxytocin receptors, and given the successful use and enthusiasm by the scientific community, we feel obliged to scale-up production of these reagents and improve their functionality. Aim 1 of the Antibody Core is to continue production of oxytocin receptor antibodies, Aim 2 is to distribute these antibodies broadly, and Aim 3 is to generate monoclonal antibodies to facilitate their broader use by Project labs and other investigators both in the US and internationally. There is clearly urgent need for these resources, which are best produced, tested, and distributed by a Core facility rather than by individual labs.

The goal of this proposal is to establish the link among stress, Ca2+ dysregulation and synapse loss in aging and a mouse model of Alzheimer's disease (AD). AD is the most common cause of dementia in the elderly. Synapse loss occurs many years before dementia and is the best correlate of cognitive impairment in AD patients. In the APPPS1 mouse model of AD, we have recently found that a fraction of dendrites of pyramidal neurons exhibit abnormal high-amplitude long-duration dendritic Ca2+ spikes, which result in synaptic depotentiation. We have also found that the deletion of glucocorticoid receptors (GR) phosphorylation at brain-derived neurotrophic factor (BDNF)-responding sites increases the amplitude and frequency of dendritic Ca2+ spikes. Based on these findings, we propose to test the hypothesis that stress hormone glucocorticoids promote abnormal dendritic Ca2+ spikes and lead to synaptic dysfunction and loss while BDNF reduces these detrimental effects by affecting GR phosphorylation and its signaling pathway. To alleviate the generation of abnormal dendritic Ca2+ spikes and their detrimental consequences on synaptic plasticity, we will investigate the impact of reducing stress hormone glucocorticoids or increasing BDNF activity by genetic or pharmacological manipulations in the AD mouse model. The proposed experiments will determine the role of stress in the generation of abnormal dendritic Ca2+ spikes and synapse loss in aging and AD pathogenesis. The proposed studies will also generate important new insights into the therapeutic treatment of AD aiming at reducing stress, Ca2+ dysregulation and synapse loss.

Oxytocin is an evolutionary conserved peptide hormone that is synthesized and released from the hypothalamus for reproduction and maternal behavior. Recent studies have tagged oxytocin as a ?trust? hormone, that promises to improve social deficits in various mental disorders, such as autism. Despite the enthusiasm for oxytocin, the efficacy of oxytocin in improving human social behaviors has been contradictory. Such inconsistencies are likely due to our poor understanding of complexity of oxytocin action and the behavioral measures that have been used in clinical trials. A better understanding of the mechanisms of oxytocin is needed to apply the therapeutic potential of this neuropeptide. Recently we showed that oxytocin enables mice to recognize infant distress calls through the auditory system that enhanced maternal pup retrieval thru oxytocin receptors. The hypothesis of this application is that the identification of downstream targets of oxytocin receptors will provide a means of analyzing oxytocin signaling across molecular, physiological, systems and behavioral levels. We have developed new assays and antibodies to follow the action of the oxytocin receptor, a G protein-coupled receptor. The aim of this project is to understand how the many actions of oxytocin are translated from its receptor signal transduction pathways. An initial goal will be to follow the downstream proteins that mediate the functions of oxytocin. This includes G proteins, calcium- dependent proteins, scaffold proteins like gephyrin and receptor tyrosine kinases, such as the BDNF TrkB receptor.

PROJECT SUMMARY The goal of this proposal is to determine if LXR? phosphorylation at serine 196 (S196) is a possible target for therapeutic intervention in Alzheimer's disease (AD). Our previous published studies demonstrated both in cultured macrophages cell lines and in mouse models of cardiometabolic diseases that the non-phosphorylated form of LXR? S196A reprograms the LXR-modulated transcriptome and produces a more anti-inflammatory response. In addition, previous studies from others have shown that LXR? is a potential target for reducing neuroinflammation, and AD pathology because genetic loss of LXR? in the APP/PS1 transgenic mouse model of AD increased the number of amyloid plaques, while its activation attenuated the inflammatory response of primary glial cultures to fibrillar amyloid peptide. As a majority of AD risk loci are in genes expressed most highly in microglia, and that LXR? is expressed in both mouse and human microglia, we hypothesize that reducing LXR? phosphorylation in microglia would restrain inflammation and diminish AD progression. To test this we will develop a mouse model that harbors a microglia-specific LXR? S196A knockin in the context of an AD-prone mouse (APP/PS1), and compare the number of AD plaques with those in wild-type littermate controls. To examine effects of LXR ? S196 phosphorylation on the inflammatory gene expression, we will generate primary glial cultures from wild-type and microglia-specific LXR ? S196A mice and measure their ability to inhibit the inflammatory response to fibrillar amyloid peptide. We will also perform RNA-seq of primary microglia generated from WT and LXR? S196A mice in the absence and presence of fibrillar amyloid peptide to reveal genes and pathways modulated by LXR ? S196 phosphorylation that can be manipulated for preventive and therapeutic purposes. Given that the LXR? inflammatory responses can be controlled by phosphorylation we will also test whether pharmacological interventions that promote the non-phosphorylated form of the wild type LXR? can protect APP/PS1 mice from AD pathology. Successful completion the aims will determine whether LXR? phosphorylation represents a tractable target for the treatment of AD due to its ability to reduce inflammatory gene expression in the brain.