Robert Sweet - US grants

An area diffractometer for crystallography has been installed at x-ray beamline X12-C at the National Synchrotron Light Source at Brookhaven National Laboratory. The diffractometer that was chosen was the FAST by ENraf/Nonius of Delft, The Nether-lands. Several projects are proposed to exploit the multi-wavelength phasing methods. Also, there is a tremendous pressure for use of the diffractometer among the existing community of crystallographers who have used film methods at the beamline. This pressure will drive the development of standardized but flexible methods for data collection and reduction. Funds are requested for an additional computer for use in this development project.

This candidate for a Scientist Development Award for Clinicians plans to develop his investigative skills in Geriatric Psychopharmacology. The elderly, particularly the very old and those with dementia, undergo age and disease related changes in drug disposition and dynamics which leave them at risk for drug toxicity and altered therapeutic response. Pharmacodynamic assessment techniques can be used to delineate the relationships between drug concentration and clinical response or toxicity, optimizing the use of drug treatments. As a vehicle for the development of expertise in the clinical pharmacologic skills needed in the pharmacodynamic assessment of psychotropic agents in late life, the candidate proposes to study the pharmacodynamics of the neuroleptics perphenazine (PZ) and melperone (MEL) in patients diagnosed with dementia of the Alzheimer's type (DAT) complicated by psychotic symptoms or behavioral disturbance and in patients diagnosed with Psychotic Major Depression (PMD). Pharmacokinetic-pharmacodynamic techniques will be used to determine the characteristics of the pharmacodynamic curves for PZ and MEL using instrumental measurement of rigidity and tremor, and plasma level of prolactin (PRL) and homovanillic acid (pHVA) as effect measures. The following questions will be addressed: (i) What is the nature of the pharmacodynamic curve for PZ and MEL in causing altered PRL, pHVA, rigidity or tremor in patients with DAT and PMD, eg linear, sigmoidal (first or higher orders), anticlockwise hysteresis?; (ii) What are the relative contributions of the concentrations of the parent compounds (PZ and MEL) versus that of their metabolites in inducing alterations in dopaminergic function, and to a lesser extent muscarinic effects, at steady state conditions?; (iii) What is the nature of the relationship between the measured changes in dopaminergic function and ex vivo determination of antagonism, by the treated patient's plasma dialysates, at cloned human Dl, D2, D3, D4, and MI receptors expressed in cell membrane suspensions from cells transfected with individual receptor subtypes? The above research, building on the candidate's work in the clinical characterization of neuroleptic-induced movement disorders in the elderly, will be accomplished in conjunction with a career development plan focusing on developing a blend of skills in clinical and laboratory pharmacologic methods of investigation. This will allow the candidate to make a unique contribution to the clinical pharmacology of aging, with the goals of elucidating the pharmacodynamics of dopamine receptors and of psychopharmacologic agents acting on dopamine systems. The candidate's work will be directed towards both the rational development of currently available agents for use in the elderly and towards leads to successful new drug discoveries.

The psychotic symptoms, delusions and hallucinations, are present in at least 30-40% of patients with Alzheimer's disease (AD). Psychotic symptoms in AD patients (AD+P) predict more rapid functional decline and premature institutionalization. Current treatments for AD+P are inadequate. We have hypothesized a polygenic model of AD+P. In preliminary tests of this hypothesis of this hypothesis, we have found that AD+P was significantly more frequent in patients with specific genotypes at the dopamine1 (D1) and D3 receptor loci (Sweet et a., 1998). Similarly, Holmes et al. (1998) reported an association in AD patients with variation in the serotonin/2A (5-HT2A) and 5-HT2C receptor genes. We propose to establish a cohort of 644 subjects, prospectively and longitudinally characterized with regard to psychosis phenotype, for examination of the genetic determinants of AD+P. Subjects with mild cognitive impairment, possible AD and probable AD will be evaluated at presentation to the Alzheimer's Disease Research Centers of the University of Pittsburgh and the University of Pennsylvania. Genetic material will be obtained. Neuropsychiatric assessments of psychotic symptoms will be conducted, with ratings on the CERAD Behavioral Rating Scale. Subjects without current or prior psychotic symptoms will be followed longitudinally with repeat assessments for psychotic symptoms every 6 months. Telephone assessments will be used for subjects unable to return to minimize incomplete data due to drop-outs. We project 20%-30% of the 644 subjects without psychosis at baseline will develop incident AD+P during the study interval. We hypothesize: 1) D1 receptor genotype will predict onset of AD+P; 2) D3 receptor genotype will predict onset of AD+P; 3) 5-HT2A receptor genotype will predict onset of visual hallucinations; 4) H-HT2C receptor genotype will predict onset of visual hallucinations. This study would be the first to prospectively evaluate the contribution of specific genes to predicting the onset of psychotic symptoms in any disorder. Replicated findings would provide a compelling rationale for family-based studies to address population stratification effects and for pursuit of the identified receptors as targets for drug development. Finally, establishing an AD cohort with prospectively determined psychosis phenotype will facilitate the research for novel risk genes as new genetic technologies become available.

DESCRIPTION (provided by applicant): Reduced gray matter volume of the auditory cortex located on the supenor temporal gyrus (S I U) is the structural brain imaging abnormality most consistently identified in the cerebral cortex of subjects with schizophrenia. Functional studies of audition similarly indicate that subjects with schizophrenia have impairments in the precision of auditory sensory memory that localize to this region. Recently, we identified that among the contributors to reduced gray matter volume in the STG of subjects with schizophrenia was reduced pyramidal cell somal volume in deep layer 3 of auditory association cortex (BA42). In this R2 I application, we propose a series of initial studies to develop a body of data necessary for the proper interpretation of the current findings and upon which future studies of auditory cortex pathophysiology in subjects with schizophrenia will be built. Specifically we will test the following hypotheses: 1) Chemoarchitectonic criteria reliably parcellate human auditory cortex into regions corresponding to the core, lateral belt and parabelt regions delineated in non-human primates. 2) Auditory lateral belt and parabelt, but not core, cortex volumes are reduced in subjects with schizophrenia. 3) Reduced deep layer 3 pyramidal cell mean somal volume in subjects with schizophrenia results from a shift to smaller size of all cells and not from a change in cell number. The planned studies are novel in that they will be the first to examine changes in volume of a chemo- or cytoarchitectonically defined region in subjects with schizophrenia, and in their rigorous application of stereo logic techniques to the determination of somal volumes and absolute numbers of pyramidal cells in subjects with schizophrenia. Successful completion of these studies will: 1) Enhance the interpretation of current and future findings by placing them in the context of the rich electrophysiologic and connectional data present in monkey through delineation of human analogues of core, lateral belt and parabelt; 2) Identify a pathologic target on which to focus future investigations by determining which chemoarchitectonic regions demonstrate reduced gray matter volume; and 3) Provide a basis for the generation of specific mechanistic hypotheses by clarifying whether cell volume or number is altered. Finally, it is anticipated that the generation of mechanistic hypotheses in future studies of auditory cortex in subjects with schizophrenia will be enhanced by the applicant's ongoing, complementary studies of the neurobiology of psychosis in Alzheimer disease.

[unreadable] DESCRIPTION (provided by applicant): Structural imaging studies indicate reductions in gray matter volume localized to the auditory cortex of the superior temporal gyms in subjects with schizophrenia. Associated with these reductions are deficits in early, pre-attentive auditory sensory processing. In non-human primates, early cortical processing of auditory input occurs through hierarchically organized auditory core, lateral belt, and parabelt cortices of the superior temporal gyrus. Feedforward projections from auditory core to lateral belt, and from lateral belt to parabelt provide for rapid transfer of sensory information, facilitating pre-attentive behavioral responses. Our initial studies of auditory cortex in subjects with schizophrenia have found reductions in pyramidal cell size in a laminar pattern indicative of alterations of feedforward projections. These findings have led us to hypothesize that schizophrenia is associated with selective impairments of the feedforward projection neurons within the auditory core, lateral belt, and parabelt. We will test this hypothesis in a series of specific aims, capitalizing on the known organization of the primate auditory cortex and designed to examine the source cells, the terminations, and the post-synaptic targets of auditory cortieocortical feedforward projections. Selective involvement of feedforward projections will be tested by similarly examining the source cells, terminations, and post-synaptic targets of feedback projections. Specificity of findings for schizophrenia will be established by examining non-human primates exposed to chronic neuroleptic treatment, and by examining subjects with mood disorder. We will address the following questions: 1) Are reductions in gray matter volume in auditory cortex present in the cortical layers from which feedforward projections arise and in which they terminate? 2) Is mean pyramidal cell somal volume of the source cells for auditory feedforward projections reduced? 3) Is total axon length and axon terminal number reduced in the termination zones of auditory feedforward projections? 4) Are there post-synaptic reductions in dendritic spine density in the termination zones of auditory feedforward projections? Successful completion of these aims will establish whether impairments in auditory cortieocortical circuits in subjects with schizophrenia are selective for feedforward projections, identify which components of the feedforward circuits are impaired, and ascertain which impairments are specific for schizophrenia. This knowledge will guide the design of future investigations of auditory cortex pathology, and inform the interpretation of psychophysiology investigations and neural modeling of auditory processing in schizophrenia. [unreadable] [unreadable]

DESCRIPTION (provided by applicant): Psychotic symptoms occur in approximately 50% of individuals diagnosed with Alzheimer Disease (AD+Psychosis, AD+P). AD+P is associated with greater cognitive decline and increased institutionalization. Current therapies have limited benefit for AD+P, and do not alter its poor prognosis. We have previously estimated the heritability of psychosis in AD as 61%-70%, indicating a substantial genetic component. Recently linkage and/or association of several novel genes with idiopathic psychosis have been reported, two of which (NRG1 and COMT) we have found to be associated with AD+P in preliminary studies. Other data suggest that variation in genes contributing to neurodegenerative pathology itself (e.g. APP, PS1, and MAPI) also alter psychosis risk. We now propose to analyze this highly probable set of candidate genes to address several questions regarding AD+P: 1) Which genes demonstrating linkage and allelic association with idiopathic psychosis, or leading to neurodegenerative pathology, increase risk for AD+P?;2) What are the effects of variation in these genes on predicting psychosis onset during AD, and how do these effects interact with cognitive impairment to increase AD+P risk?;and, 3) ls there evidence for subtypes within AD+P and how are they influenced by genotype? We will address these questions in three aims, involving three cohorts. Single locus and haplotype associations of NRG1, DTNBP1, DISC1, COMT, DAOA (formerly G72), AKT1, RGS4, APP, PS1, PS2, and MAPI with AD+P will be tested in a large (N=1000) AD+P vs AD-P Case-Control Cohort. Significant associations will be confirmed in a similarly large Family Cohort. Confirmed associations will be further evaluated for the prediction of AD+P onset in a Prospective Cohort of 786 AD and Mild Cognitive Impairment subjects without psychosis at study entry. Mediating and moderating interactions between genetic variation and cognition on AD+P onset will be evaluated. Longitudinal data from the Prospective Cohort will be used to identify subtypes of AD+P with differing trajectories and genetic determinants. Successful completion of these aims will identify genetic predictors of AD+P, indicate if they act via an effect on cognition, and evaluate if they affect all individuals uniformly or result in subtypes. These findings may guide the development of interventions for the prediction, treatment, and/or prevention of psychosis and excess cognitive morbidity in AD.

DESCRIPTION (provided by applicant): Reduced layer 3 pyramidal cell dendrite length and complexity, spine density, and somal volume have been reported in multiple brain regions, including in primary auditory cortex (AI), in schizophrenia (Sz). Because these structural features are critical for signal processing, they likely underlie the correlated observations of impaired auditory processing and auditory cortex gray matter volume reductions in Sz, and contribute to disability. Dendrite length, complexity, and spine density are shaped by the effects of activity-dependent glutamate signaling on the microtubule and actin cytoskeleton; disruption of this signaling causes structural reductions similar to those in Sz. During the current funding period we have found alterations of proteins at multiple points within this pathway: presynaptic- SYN1, SYP; receptor- GRIA3; signal transduction- kalirin-9, MAP2. These findings have led us to hypothesize that glutamate signaling to the cytoskeleton is altered in AI in Sz, and contributes to the impairments in pyramidal cell structure. We now propose to test this hypothesis in an integrated set of experiments designed to delineate the specific nature of the alterations in these proteins within AI using a combination of targeted proteomics of synaptosomal preparations and quantitative fluorescent microscopy in human tissue (Aim 1 & 2); to determine the mechanisms by which these alterations may lead to morphologic changes in layer 3 pyramidal cells using over-expression and RNAi for WT and mutant kalirin-9, RhoA, RAC1 and MAP2 constructs in vitro and in layer 3 pyramidal cells in AI in vivo (Aim 3); and to place the alterations in the context of the larger glutamate signaling network in AI using targeted proteomics and network co-expression topology analyses (Aim 4). These Aims provide potential translational impact by examining proteins (i.e. possible drug-able targets) and by the integration of approaches such that alterations can be discovered, and their specificity delineated in diseased tissue, and then their mechanisms determined in model systems. Inclusion of an in vivo model provides a bridge to future studies to test interventions derived from our mechanistic findings with the goal of preventing morphologic changes in layer 3 pyramidal cells in AI and assessing the effects on auditory function.

? DESCRIPTION (provided by applicant): This proposal requests support for continuation of T32 MH16804 (Years 36-40). The most recent renewal (Years 31-35) proposed to reinvigorate this long term successful T32 by shifting the emphasis of training from predominantly clinical research to one providing translational neuroscience research training. We can now report that this transition has been highly successful as evidenced by a number of metrics: recruitment of translational neuroscience investigators, including increased numbers of M.D., Ph.D. trainees, female trainees, minority trainees, and trainees with disabilities; high rates of first grant fundig of graduates; research quality (as measured by the impact factor of journals in which appointees have published), and; successful placement of graduates. The achievements of T32 MH16084 have been mirrored by a substantial expansion of the Faculty of the Translational Neuroscience Program within the Department of Psychiatry at the University of Pittsburgh, and a corresponding increase in the number of outstanding applicants, such that the annual number of eligible applicants has exceeded our slots 10-fold. As a result, we look to expand the number of postdoctoral trainee slots in the current application to a total of five. This will afford opportunties to these many outstanding candidates and provide a greater critical mass for translational neuroscience training activities. All trainees benefit from our established training program in translational neuroscience which has been designed to provide practical training in techniques and strategies such that trainees' resulting research can be translated across multiple levels of discovery. Trainees with prior basic neuroscience training further receive clinical exposures designed to help them develop fluency in the clinical, pathophysiologic, and pathologic manifestations of mental illness, and; clinically trained individuals enhance their fluency in basic neuroscience knowledge. In addition, our trainees benefit from the development of individualized training plans and from participation in our highly successful Career and Research Development curriculum. T32 MH16804 continues to be led by Robert A. Sweet, M.D., a senior translational neuroscience investigator with a record of outstanding mentorship of translational neuroscience investigators. Dr. Sweet will be supported by new Co- Director, Mary L. Phillips, M.D., M.D. (Cantab), a senior clinical and translational neuroscience investigator and acclaimed mentor of imaging neuroscience investigators. Our Program Faculty has been enriched by a number of investigators who bring many additional state of the art approaches to translational neuroscience studies of mental illness. By combining the strong track record in the successful training of psychiatry researchers established during the past 34 years with the emphasis on new discovery and new methodologies developed during the past 4 years of funding, T32 MH16804 is now poised to impact the field by preparing an expanded cohort of translational neuroscientists to make transformative discoveries in psychiatry.

The Center's Central Hypothesis posits that layer 3 pyramidal cells (PCs) in subjects with schizophrenia have a cell type-autonomous pathology that is refiected in altered somatodendritic morphology and that differs in severity across regions in the cortical visual working memory and attention network. These abnormalities of layer 3 PCs result in locally reduced excitatory drive, refiected in reduced markers of metabolic activity in layer 3 PCs and reduced activity-dependent markers in reciprocally-connected layer 3 parvalbumin (PV)-expressing basket cells. This model leads to several novel predicfions. For example, that deflcits in layer 3 PC somal volume and dendritic spine density are present in mulfiple cortical regions, but moderated by region-specific factors (Aim 1). To date only limited analyses of primary visual cortex (VI) have been conducted, and the posterior parietal cortex (PPC) has not been examined. Our preliminary data indicate that impairments in dorsolateral prefrontal cortex (DLPFC) are associated with reduced markers of local network activity within PCs and PV basket cells. Functional data indicate impaired activity within VI and PPC during visual tasks in subjects with schizophrenia. Thus, our model predicts that markers of neuronal acfivity are also altered within VI and PPC (Aim 2). Finally, reducfions in pre-synapfic proteins such as synaptophysin and synapsini, that are known to impair glutamatergic bouton funcfion, behavior, and cognifion, have been previously observed in schizophrenia. Our model predicts that reductions in these proteins predominate in intracortical glutamatergic boutons within layer 3 across V1-PPC-DLPFC and are posifively correlated with the magnitude of the underlying somatodendrific abnormalifies within regions in the network (Aim 3). This project serves as an essenfial link between disease-related molecular findings in these same neurons, layers and regions (Project 1) and abnormal information processing in disease (Project 5). This project will constrain the interpretation of how normative functional connectivity (Projects 4 & 5) is altered in disease (Project 5) and will guide predicfions for future studies using markers specific for projections between PPC and DLPFC that may be identified in Project 3.

Core B: Clinical Core Abstract: Progress in the diagnosis, treatment, and prevention of Alzheimer's Disease (AD) depends critically on the availability of large cohorts of subjects spanning the transition from normal through preclinical AD stages, mild cognitive impairment (MCI), and ultimately to early AD. The longstanding goal of the University of Pittsburgh ADRC (PITT-ADRC) Clinical Core has been to enroll these subjects, clinically characterize and longitudinally evaluate them, sample them for genetic, brain imaging, and other biomarkers, enroll them in clinical trials, and obtain their consent for the provision of autopsy tissue for further discovery. The PITT-ADRC Clinical Core has been highly successful in meeting this objective. The PITT- ADRC Clinical Core has evaluated a cohort of more than 4000 subjects since its inception, which has contributed substantially to advancement of knowledge regarding the natural history of AD, its genetic basis, the development of amyloid imaging, psychiatric comorbidities and their underlying neurobiology. During the current funding interval the Clinical Core has developed approaches to expand enrollment of individuals along the complex transition from normalcy to dementia, including Normal Control subjects, individuals with subjective cognitive decline (SCD), individuals with impaired cognitive tests (without SCD), and individuals with MCI. At present these four groups constitute nearly 40% of our annual enrollment and comprise more than 50% of our nearly 700 active subjects. These subjects provide a critical resource for many investigations in the PITT-ADRC, especially those emphasizing imaging biomarkers (including the planned Projects 1 and 2). During the current period we have maintained our strong history of neuropsychiatric characterization of all subjects and further enhanced our rate of autopsy consent, which will support the planned Project 3. Finally, we have continued are strong track record of providing genetic samples and data on large numbers of subjects annually to the Neurogenetics Core for use in local R01s and in national and international consortia. These accomplishments have prepared the PITT-ADRC Clinical Core to maintain its productivity in the following set of proposed Specific Aims: 1) To perform evaluations at study entry and at annual follow-up of Normal Control, pre-MCI, MCI, AD, and related dementia subjects participating in the PITT-ADRC; 2) To assure maximum participation in clinical, brain imaging, and autopsy studies by providing appropriate research subject referrals and clinical services during longitudinal follow-up; 3) To provide clinical data, research subjects, DNA samples, and technical and scientific leadership to support new and ongoing research projects at the PITT-ADRC, within the University of Pittsburgh, and to support national consortium studies; 4) In collaboration with the ORE Core, to facilitate recruitment of diverse participants at the earliest end of the AD spectrum into the Clinical Core, Projects 1 and 2, and ancillary studies; 5) To provide a platform of clinical evaluation, research subjects, and data to support education and training of the next generation of dementia researchers.

Project 3: Psychosis Abstract: A more severe phenotype of Alzheimer disease (AD) is identified by the occurrence of psychosis. AD with psychosis (AD+P) is common, with a cumulative incidence of ~ 40%-60% in subjects with AD. AD+P subjects have more rapid cognitive decline, increased disability, and greater mortality than AD subjects without psychosis (AD-P). Current empiric treatments for psychosis in AD have limited efficacy and are associated with substantial toxicity, motivating efforts to identify the underlying neurobiology of AD+P. We have assembled a large brain tissue collection of AD cases characterized antemortem for psychosis, placing us in a unique position to address this need. This project will test our overarching model that AD+P results from specific biologic processes that modify AD-related neurodegeneration, yielding more rapid cognitive decline and psychotic symptoms. This model initially derived from our observation that the occurrence of psychosis in AD is familial, a finding which has since been replicated in two independent cohorts. Brain imaging and neuropathologic studies provide further evidence of a characteristic neurobiology of AD+P, with exaggerated reductions of gray matter volume, blood flow, glucose metabolism, and increased phosphotau (pTau) burden in multiple neocortical regions. Additional AD+P risk may also result from comorbid neocortical stage Lewy body pathology. Nevertheless, in our preliminary data, after accounting for all of these pathologies, unexplained causation of psychosis in AD remains. The more rapid cognitive decline in AD+P, and observations that synapse loss is the strongest correlate of cognitive impairment, suggest that synaptic dysfunction and loss is one source of the missing neuropathology in AD+P. Additionally, recent genetic studies have highlighted inflammation as having a more central role in AD neurodegeneration than previously appreciated, and inflammation, especially when affecting synaptic proteins, is strongly associated with psychosis. We therefore propose a set of specific aims designed to determine the proportion of AD+P explained by these pathologies: 1) To quantify the burden of AD and comorbid neuropathologies within neocortical regions in AD+P and AD-P subjects; 2) To evaluate markers of synaptic dysfunction and loss in AD+P; 3) To evaluate markers of inflammation in AD+P. Combining a Sr. Investigator (Sweet) with expertise in the synaptic pathology of psychosis and a Jr. Investigator (Kofler) with expertise in the neuropathology and immunology of AD provides strong scientific synergy, increased likelihood of success, and an opportunity for career development. Completion of these aims will provide the necessary basis for future mechanistic studies assessing whether interventions to alter affected pathways (pTau, synaptic signaling & inflammatory) may slow synaptic impairment and cognitive decline downstream of A? in model systems. In addition, our findings will inform how much each pathologic process contributes to AD+P risk, and allow evaluation of whether that weighting differs across individuals, which could be important for future efforts at personalized therapeutics.

PROJECT SUMMARY/ABSTRACT Up to 10% of newborns need help breathing at birth, and up to 1% requires extensive cardiopulmonary resuscitation to survive. The frequency of neonatal resuscitation means that healthcare providers caring for newborns must be trained and ready to provide optimal resuscitation when needed. The gold standard for neonatal resuscitation training is simulation using neonatal simulation manikins. Providing effective training in neonatal resuscitation requires simulations that mimic human neonates in both form and function. The current generation of neonatal simulators lack adequate fidelity. Additionally, they cannot simulate neonatal physiology or provide automated feedback. The University of Washington (UW) Neonatal Education and Simulation-based Training (NEST) Program has performed a series of investigation on neonatal simulator fidelity and identified gaps in simulator fidelity. The UW Center for Research in Education and Simulation Technologies (CREST) Laboratory has previously developed a high-fidelity adult simulator that accurately replicates human anatomy to the finest details and includes automated feedback. In the proposed project, the NEST Program and CREST team will leverage their respective expertise to create the next generation neonatal simulator. The simulator will represent a quantum leap in fidelity and functionality over current neonatal simulators, and will greatly enhance neonatal resuscitation training. We propose to validate the next generation simulator by comparing it against two commercially available `high-fidelity' neonatal simulators and by performing a pilot study on neonatal endotracheal intubation success after training with the new simulator. The project is significant in that neonatal resuscitation is common, and that suboptimal resuscitation efforts can have devastating and lifelong consequences. Healthcare providers who attend neonatal deliveries are trained in neonatal resuscitation using simulators. These simulators must have high levels of structural and functional fidelity in order to serve as an effective training platform. Current simulators lack adequate fidelity. The project is innovative in that it will leverage the experience of the investigators in developing high-fidelity adult simulators towards the development of a next generation neonatal simulator. The simulator will be based on neonatal MRI scans and created using state of the art 3-D printing and tissue modeling techniques. The next generation simulator will contain integrated physiology software and provide automated feedback. The final product will be more lifelike than any current simulator and will enhance neonatal resuscitation training. Completion of the project will result in the creation of a next generation neonatal resuscitation trainer that will improve neonatal resuscitation training. This improved training will result in better neonatal resuscitation performance and ensure a smooth neonatal transition for a healthy beginning, and lay a foundation for optimal short- and long-term outcomes for all newborn infants

PROJECT SUMMARY: Psychotic symptoms occur in ~ 40-60% of individuals with Alzheimer Disease (AD with psychosis, AD+P). Numerous studies have found that the AD+P phenotype is associated with more rapid cognitive decline than AD subjects without psychosis (AD-P). Current, empirically developed, treatments for psychosis in AD have limited efficacy, do not alter the more rapid disease progression, and are associated with substantial toxicity, including excess mortality. Because the annual incidence of psychosis in AD is only ~ 10%, there is a window of opportunity to intervene to prevent psychosis onset if resilience factors can be identified. Multiple brain imaging studies have shown that relative to AD+P, subjects with AD-P have preserved indices of cortical synaptic function, especially in the dorsolateral prefrontal cortex (DLPFC). Our recent genetic and proteomic findings in patients and model systems have converged on a possible mechanism to explain this synaptic resilience in AD-P: Preservation of postsynaptic density (PSD) protein levels in DLPFC. First, using targeted mass spectrometry (MS) in DLPFC grey matter homogenates from mild to moderate AD subjects, we found a robust increase in homogenate levels of canonical PSD proteins in AD-P subjects relative to both AD+P and Control subjects. Second, we identified and independently confirmed a polygenic protection against psychosis in AD which included an allele associated with reduced DLPFC expression of TOM1L2. TOM1L2 is an adaptor protein that facilitates degradation of synaptic proteins via actin-based endocytic trafficking. Finally, in the APPswe/PSEN1dE9 mouse model of A? overproduction, we found that reduction of Kalrn, a Rac1/RhoA guanine nucleotide exchange factor that regulates endocytic trafficking, elevated canonical PSD protein levels in cortical homogenates, preserved these proteins' levels in PSD enrichments, and protected against psychosis-associated behaviors. We thus hypothesize: resilience to psychosis onset in AD is conferred by preservation of protein levels in PSD enrichments, due to reduced trafficking of PSD proteins for degradation, and can be used to identify novel therapeutics. We will test this hypothesis in three Aims: Aim 1) To determine if PSD proteome alterations and gene-protein interactions are associated with resilience to AD+P; Aim 2) To test the effect of reduction in Tom1l2 on the synaptic proteome in a mouse model, and; Aim 3) To use computational chemogenomics to identify drugs that induce synaptic proteome compensations which confer resilience to AD+P, providing for rational prevention and/or treatment. The above aims benefit from the tight integration and leveraging of Multiple PIs with expertise in the synaptic pathology of psychosis (Sweet), the neuropathology of AD (Kofler), and the use of computation for novel therapeutic discovery (Wang). Upon completion, we will have delineated the synaptic protein compensations associated with resilience to psychosis in AD and discovered leads to compounds that generate synaptic resilience for future testing in future studies.

Core B: Clinical Core Summary/Abstract: Progress in the diagnosis, treatment, and prevention of Alzheimer?s Disease (AD) depends critically on the availability of large ?trial-ready? cohorts of participants spanning the transition from normal through preclinical AD stages, mild cognitive impairment (MCI), to early AD. The PITT-ADRC Clinical Core has effectively accomplished this, evaluating a cohort of more than 4700 participants since its inception and providing participants, biologic samples, and data for a wide array of studies that depend critically on differing clinical populations: participants at risk for AD (e.g. prevention, biomarker studies); participants with clinical AD (e.g. GWAS of AD, GWAS of psychosis); participants with autopsy-confirmed AD (e.g. postmortem-tissue studies); and participants with other dementias (e.g. DLB consortium). The Clinical Core has developed approaches to maximize flexibility in meeting the needs of these diverse, and evolving, set of supported investigations. In addition to its role as a critical resource for many funded studies in the PITT-ADRC, the Clinical Core will provide participants that will serve as a focus for biomarker evaluation by the Neuroimaging Core and the Biomarker and Neurogenetics Core. During the current period we have also maintained our strong history of neuropsychiatric characterization of all participants and further enhanced our rate of autopsy consent, supporting the Neuropathology Core and multiple affiliated R01s. We have continued our strong record of providing genetic samples and data on large numbers of participants annually for use in local R01s and in national and international consortia. Finally, we have added new investigators with specialized expertise in Parkinsonian syndromes and FTLD and have developed new procedures to increase the rate of completed follow-up visits for our participants. These accomplishments have prepared the Clinical Core to maintain its productivity in the following set of proposed Specific Aims: 1) To perform evaluations at study entry and at annual follow-up of Normal Control, pre-MCI, MCI, AD, and related dementia participants participating in the PITT-ADRC; 2) To assure maximum participation in clinical, intervention, brain imaging, biomarker, and autopsy studies by providing appropriate research study referrals and clinical services during longitudinal follow-up; 3) To provide clinical data, research participants, DNA samples, and technical and scientific leadership to support new and ongoing research projects at the PITT-ADRC, within and outside the University of Pittsburgh, and to support national consortium studies; 4) In collaboration with the Outreach, Recruitment, and Engagement Core, to facilitate recruitment and retention of diverse participants; 5) To support the Research and Education Component in training the next generation of dementia researchers by providing research participants, samples, and data.