Jada Lewis - US grants

TAR DNA-binding protein of 43 kDa (TDP-43) proteinopathy is a new family of disorders whose classification originated with the discovery of cytoplasmic and nuclear inclusions composed of ubiquitinated, hyperphosphorylated TDP-43 in a subset of individuals with the neurodegenerative diseases Frontotemporal Dementia (FTD) and Amytrophic Lateral Sclerosis (ALS). TDP-43 inclusions have now been observed in a group of secondary TDP-proteinopathies including Alzheimer's Disease (AD), Dementia with Lewy Bodies (DLB), Pick Disease (PiD), and hippocampal sclerosis. Mutations in the TARDBP gene which encodes TDP-43 have now been associated with both sporadic and familial cases of pure ALS. Additionally, mutant TDP-43 has been implicated in a small number of individuals presenting with frontotemporal lobar degeneration with amyotrophic lateral sclerosis (FTLD-ALS) or with pure FTD. While similar mutations have not been identified in secondary TDP-43 proteinopathies, it is now clear that TDP-43 can directly lead to neurotoxicity, at least in the context of mutation. Post-translational generation of C-terminal fragments (CTF) of TDP-43 is key feature of the disease with the 25kD CTF of TDP-43 being prominently found in a number of TDP-43 proteinopathies. The lack of mouse models of TDP-43 aggregation and neurotoxicity currently prevents the in vivo testing of potential therapies directed against TDP-43 proteinopathies. Our overall goal of this proposal is to generate a mouse model of TDP-43 proteinopathy which will serve as an invaluable tool in drug development for ALS, FTD, and secondary TDP-43 proteinopathies. Aim 1: To generate a mouse model of TDP-43 neurotoxicity mediated by the inducible expression of 25kD CTF TDP-43 protein. Aim 2: To identify which aspects of TDP-43 proteinopathy may be targets for therapeutic intervention.

DESCRIPTION (provided by applicant): Over the past few years, there has been increasing exploration of the potential for gene silencing or knockdown therapies in the treatment of neurodegenerative disorders. The technology has progressed to a point in which a phase 1 human therapeutic trial for familial amyotrophic lateral sclerosis has been initiated. Current knock-down therapies under investigation include viral vector delivery of shRNAi or microRNA mimics, delivery of naked RNAi and RNAi complexed with various reagents to facilitate uptake, and delivery of modified antisense DNA oligonucleotides. The mechanisms of action for these approaches include modulation of mRNA translation, modulation of pre-mRNA splicing, and degradation of mRNA and pre-mRNA. These various approaches have been tested in pre-clinical animal models to varying extents with varying levels of efficacy. A glaring limitation of these studies that have been conducted thus far is that it has generally been impossible to monitor the efficacy of knock-down in real time. To overcome this limitation, we propose two Aims that are designed to build capability to track the efficacy of knock-down in real time and provide proof of concept studies in mouse models of two neurodegenerative diseases that are potential targets for gene silencing efforts. Taking advantage of the expertise of the investigators involved, we plan to focus on models for Huntington s disease and fronto-temporal dementia. These disorders are prime candidates for gene-silencing therapeutics and previous work in modeling these disorders in mice has produced models that recapitulate aspects of each disorder. In the approach described here, we seek to generate models in which we will produce assayable and observable behavioral phenotypes while simultaneously being able to monitor the efficacy of gene silencing reagents in real-time. In Aim 1, we will generate mice that express mutant forms of human tau fused in-frame to luciferase. In Aim 2, we will similarly generate mice that express mutant Nterminal fragments of huntingtin fused in-frame to luciferase. In both constructs we will employ a technique that facilitates post-translational processing of the poly-protein to liberate the luciferase so it can be assayed independently of pathologic accumulations of mutant tau or huntingtin. We propose to use new in vivo imaging techniques to detect and measure bioluminescence catalyzed by the expressed luciferase. In the tau model we propose to generate, we expect the animals to develop measurable memory deficits with neuropathological abnormalities that include neuronal loss and neurofibrillary tangle pathology. In the Huntington s model, we similarly expect to induce assayable phenotypes, which include motor function deficits, reduction in the transcription of a subset of genes in striatum, hypoactivity, and premature death. Thus, one could ultimately have models with dual readout capability in which reductions in expression could be monitored in real-time by monitoring luciferase activity levels while simultaneously having disease-relevant phenotypes to assay. PUBLIC HEALTH RELEVANCE: The studies proposed in this application are designed to produce and characterize new animal models for pre-clinical testing of gene silencing approaches for intractable human neurodegenerative disease. The innovative models we propose will allow real-time, in vivo, assessments of the efficacy of gene silencing or gene knockdown therapies, allowing investigators to move to Phase I clinical trials with the most optimized and specific therapeutic available. Disclaimer: Please note that the following critiques were prepared by the reviewers prior to the Study Section meeting and are provided in an essentially unedited form. While there is opportunity for the reviewers to update or revise their written evaluation, based upon the group's discussion, there is no guarantee that individual critiques have been updated subsequent to the discussion at the meeting. Therefore, the critiques may not fully reflect the final opinions of th individual reviewers at the close of group discussion or the final majority opinion of the group. Thus the Resume and Summary of Discussion is the final word on what the reviewers actually considered critical at the meeting.

DESCRIPTION (provided by applicant): The tau protein plays a fundamental role in the cytoarchitecture of the brain and in axonal transport; however, its function and regulation can be disrupted as it becomes hyperphosphorylated and aggregated in a family of neurodegenerative diseases termed tauopathies. Tau mutation is causative for the tauopathy frontotemporal dementia and parkinsonism linked to chromosome 17 (FTDP-17t) while tau polymorphisms are associated with an increased risk of other parkinsonisms including progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and Parkinson disease (PD). Interestingly, PD is not primarily classified as a tauopathy, although a significant subset of cases also develop aggregated, hyperphosphorylated tau pathology. The gene that encodes the tau protein has been repeated identified as a risk locus in genome wide-association studies for PD. Furthermore, the co-PI of this proposal and others have shown that the PD-linked protein alpha-synuclein and tau can interact to exacerbate PD-relevant pathologies. More recently, pathological studies of individuals carrying PD-linked mutations in the LRRK2 gene have shown tau pathology in a subset of mutation carriers. Additionally, transgenic mice expressing LRRK2 with PD-relevant mutations present with abnormally phosphorylated tau. Despite these lines of evidence, the link between PD and tau, specifically through the action of LRRK2, has been largely deemed circumstantial as even the role of LRRK2 in normal biology has been unclear. Our preliminary data suggests that LRRK2 plays a regulatory role in tau biology and that this role may have implications in neurodegenerative diseases. In the current proposal, we will directly assess using several complementary methods including in vitro, cell culture, and transgenic mouse studies if LRRK2 and tau interact in normal and disease biology, providing important insights for the development of novel therapeutic approaches.

DESCRIPTION (provided by applicant): Protein aggregation is a major pathological hallmark of neurodegenerative diseases such as Alzheimer's disease (AD) and frontotemporal lobar degeneration (FTLD); and the role of some form of misfolded protein (oligomer or inclusion of ¿-amyloid peptide or tau) in inducing a cascade of events that produces symptoms is largely undisputed. Although originally a 'one protein aggregate, one cause, one disease' hypothesis was the dominant ideology, over the last decade it has become clear that these disorders are more heterogeneous with multiple protein aggregates present in any one specific disease. In most cases, the mixed pathology involves proteins that have been identified as intrinsically vulnerable to self-seeded misfolding and aggregation (TDP-43 is an example). The mechanisms that underlie the appearance of these mixed pathologies is poorly understood with a leading hypothesis being that the accumulation of one misfolded and aggregating protein negatively impacts the function of the network of activities that mediate protein folding and degradation (the proteostasis network). Loss of proteostasis function is proposed to lead to secondary misfolding of vulnerable proteins. We propose to test the hypothesis that the accumulation of Alzheimer-type amyloid and FTLD-type neurofibrillary tangles can induce the aggregation of a secondary reporter protein that is inherently vulnerable to misfolding and aggregation in transgenic mouse models. Mice that express the reporter, which consists of a variant of superoxide dismutase 1 fused to yellow fluorescent protein (SODG85R:YFP), at levels just below the threshold to initiate self-seeded aggregation, will be crossed with both mice that develop Alzheimer-like amyloidosis and mice that develop tauopathy. Outcomes in these mice will be compared to that of crosses of mice that express SODWT:YFP, which is much less prone to aggregation, with the same amyloid and tauopathy models. For reasons explained within the proposal, we contend that the SOD1-based vectors are well suited for the questions posed by this application. Our goal in these experiments is to establish whether the accumulation of one type of misfolded protein in the mammalian CNS diminishes proteostasis function to such a level that the system fails to prevent the secondary misfolding of other proteins that are intrinsically vulnerable to self-seeded aggregation.

DESCRIPTION (provided by applicant): Project Summary Alzheimer's Disease (AD) is now recognized as a disorder with a long incipient phase in which a myriad of pathologic abnormalities occur long before the first disease symptoms appear. The first pathologic event is the deposition of A¿ peptides in deposits of diffuse amyloid and in structures referred to as senile plaques. These changes may begin to occur some 20 years before the onset of symptoms. At death, individuals that exhibit only amyloid pathology are largely cognitively normal. Individuals that exhibit mild cognitive impairment at the time of death may exhibit a range of pathologic features, but a large subset show abundant amyloid pathology and some level of abnormal tau pathology (ranging from accumulation of phosphorylated tau to neurofibrillary tangles). Individuals that exhibit more severe cognitive impairment, meeting clinical criteria for diagnosis of AD, at autopsy will invariably have significant tau pathology alng with amyloid (more variable in severity). This human data argues persuasively that the deposition of amyloid in some manner induces a secondary misfolding of tau. However, the inability to model the staged transition from primarily amyloid pathology to amyloid and tauopathy has impeded our ability to define the molecular mechanisms that underlie the apparent secondary induction of tau pathology in AD. To date there have been multiple attempts to produce models that replicate this important feature of AD using various transgenic and gene-targeting approaches. A key drawback to the transgenic models has been that often there is a need to express high levels of a transgene in order to raise the levels of aggregating proteins high enough that they will spontaneously seed fibrillar aggregation. With this R21, we seek to determine whether seeding amyloid pathology in mice that express much lower levels of mutant human APP and Tau will produce models in which amyloid precedes the appearance of tau pathology in a manner that is completely dependent upon the induction and severity of the amyloid pathology (as appears to occur in humans). We propose that we can generate hosts that would accomplish this goal by generating mice that co- express low levels of mutant human APP (amyloid deposition first appears at 18 months) and mutant human tau (no pathology). We hypothesize that seeded induction of amyloid deposition in mice that co-express these transgenes will create a model in which amyloid deposition in specifically accelerated, followed by a secondary induction of tau pathology. We propose that if successful, such models could be used to better understand the mechanisms that drive the transition between primarily amyloidosis to amyloid with tau pathology.

DESCRIPTION (provided by applicant): One of the major gaps in our understanding of the evolution of Alzheimer's disease is how the deposition of amyloid triggers tauopathy. Moreover, it is now widely recognized that it is common for the CNS of individuals with a neurodegenerative phenotype to develop multiple pathologic abnormalities. The basis for the preponderance of mixed pathology is poorly understood. We hypothesize that insults that compromised function of the proteostasis network may lay the foundation for the development of mixed proteinopathies. The basic concept here is that high levels of misfolded proteins produce an added burden on the proteostatic network by occupying various activities required to dissociate such aggregates and degrade the misfolded proteins. This concept was first uncovered in C. elegans models, where the expression of proteins that produce intracellular inclusions leads to the secondary misfolding of by-stander proteins that are particularly dependent upon the proteostatic network. Recently, we have extended this concept to mammalian model systems. In proteomic studies of brain from mice with high levels of Alzheimer-amyloidosis, Drs. Xu and Borchelt identified a number of cytosolic proteins that appeared to lose solubility - a finding that is consistent with the hypothesis that amyloid deposition can, by some manner, impinge on the function of the proteostatic network to cause secondary misfolding. The Lewis laboratory also recently found that two independent lines of mice that model tau pathology also develop cytoplasmic TDP-43 immunoreactive inclusion pathology. Thus, in our mouse models, we are beginning to uncover evidence that the accumulation of one misfolded protein, can by some manner, impact on the folding of others. Our central hypothesis is that these secondary pathologies are the consequence, at least in part, of a disturbance in the cellular protein quality control network, or proteostasis network, to cause collateral misfolding. In the present application, we propose 3 Aims that seek to determine the contribution of proteostatic network dysfunction to the evolution of AD-related pathology. Aim 1 will create a novel paradigm in which mutant tau expression is induced in a preexisting environment of amyloid pathology and disturbed proteostatic function. Aim 2 will determine how the mixed pathology of AD may synergize to produce by-stander misfolding and whether the severity of such misfolding produces functional deficits in critical cellular processes (e.g. energy metabolism). Aim 3 will determine whether augmentation of proteostatic networks mitigates by-stander misfolding. Collectively, these studies will provide new insight into how AD-related pathology impacts CNS protein homoeostasis and whether augmentation of the network in later stages of disease may provide significant benefit.

Is there a form of benign brain amyloidosis in aging? Although relatively rare, the identification of aged individuals with significant amyloid pathology (lacking tauopathy) that are cognitively normal is one of the lines of evidence that argues against the notion that amyloid-? (A?) deposition is a direct mediator of cognitive decline. Our study seeks a potential explanation for cases of amyloidosis that appear benign by testing the hypothesis that the brains of these pathologic aging (PA) individuals, as compared to Alzheimer disease (AD) brain, contain a distinct conformer of A? assembly that is essentially benign. One potential explanation for amyloid pathology that is benign, in regard to cognition, is that A? may assemble into structures that are conformationally distinct, with some conformations possessing an activity that diminishes cognitive function while others do not. To address this question, we will take advantage of recent studies that have shown that rate and character of amyloid deposition in vulnerable transgenic mice can be greatly influenced by injecting homogenates from human Alzheimer?s disease (AD) brains into their brains. Our preliminary studies, presented below, demonstrate that we have extended this model system to include brain homogenates of PA brains. As expected, we observed robust acceleration of A? pathology in transgenic APPswe/ind mice that were injected with two different AD brain homogenates. Although less consistent, we similarly observed accelerated amyloid pathology in mice injected with brain homogenates from 4 PA cases, with one seeding comparably to AD brain. We propose to seed the brains of two distinct lines of transgenic mice that develop amyloid pathology late in life with homogenates from AD and PA brains, and then assess whether pathology induced in these animals causes cognitive impairment. If PA represents a form of A? amyloidosis that is benign, then we would expect that only the mice seeded with AD homogenates will develop cognitive deficits. Apart from clarifying the distinction between PA and AD, our study may have therapeutic implications. If there are forms of A? amyloidosis that are benign, then it might be possible to chemically modulate the conformer of A? that is associated with cognitive decline to favor the benign forms and thus reduce the burden of A? assemblies that diminish cognitive function.

ABSTRACT Alzheimer's disease is a devastating and ultimately fatal neurodegenerative disorder that severely compromises normal cognition and behavior. Costs associated with caring for individuals suffering from AD now exceed 250 billion dollars annually and are expected to rise exponentially in the foreseeable future. Despite this staggering statistic, there exist few treatments and no cures for AD and related dementias. Significant advances in the treatment of AD will require scientists to cross traditional boundaries between disciplines. Indeed, there is increasing recognition that AD is pathologically, genetically, and/or clinically linked to a number of other dementing diseases. Moreover, it is clear that a fuller understanding of how primary risk factors and co- morbidities in AD influence disease progression could reveal novel targets for improving patient outcomes. The overarching goal of this proposal is to build upon outstanding infrastructure for neuroscience training and the vast expertise in AD research at the University of Florida to create a pre-doctoral training program that will foster the development of the next generation of AD researchers and equip them with the broad perspective and scientific skills necessary to make true advances in the treatment of this devastating and complex disease. Trainees for this program will be selected from a pool of outstanding students from diverse backgrounds who are admitted into one of two graduate programs?a biomedical science program and a clinical health psychology program. Trainees would benefit from (1) intensive mentorship in research concepts and methodology, scientific analysis and interpretation (2) opportunities to train and interact with world-class faculty who are leading authorities in the field of AD, aging and co-morbidities of this disease (3) diverse dissertation committees that include multiple mentors with distinct realms of expertise in order to promote broad-based and comprehensive training in AD research (4) assistance integrating large scale, open source data supported by NIA such as AMP- AD and ADNI into their own research (5) personalized mentorship in professional development including grant writing, oral presentations, and networking. Finally, this training program is designed to maximize interactions among trainees and training faculty that cross levels of analysis and to create a rigorous but supportive training environment that will prepare trainees for success in laboratory science and provide them with the knowledge and skills required to make a significant impact in advancing treatments for AD.

The MPIs for this proposal independently co-developed and thoroughly characterized some of the most commonly used mouse models for research on Alzheimer?s disease and related disorders (ADRD); however, all existing tau and/or amyloid mouse models still have shortcomings which limit their utility and the questions that they can be used to answer. For example, the rTg4510 model which expresses human P301L tau through a doxycline-repressible system is one of the gold standard models in the field; however, rTg4510 is limited, in part, by its dependence on two unlinked transgenes, the early onset of tauopathy and cognitive dysfunction, and the leakiness of the tau expression. The overall goal of this proposal is to develop new models for the Alzheimer?s Disease field that overcome the shortcomings of existing models, ultimately providing an innovative platform in which the sequential nature of amyloidosis and tauopathy and the molecular pathways underlying their interaction can be examined in a streamlined, cost-effective manner. Under Aim 1, we propose to generate a model in which the CamKII-tetracycline transactivator transgene and the tau responder transgene (either WT or P301L) required for the conditional expression of tau will be co-injected and thus co-integrated into the murine genome which can subsequently transmit as a single allele. We will strive to develop a P301L tau/tTA model that will develop pre-tangle pathology at 12-15 months and tangles at 18 months of age. This new model will subsequently be fully characterized biochemically, pathologically, cognitively and structurally using MRI. Once established, these novel, conditional tau transgenics will provide a less expensive, more accessible model that develops tauopathy in mid to late life; enabling both studies aimed at accelerating and at slowing/abrogating the tauopathy. We also anticipate that this model, like the JNPL3 and rTg4510 tau models, will develop neuroinflammation and secondary TDP-43 proteinopathy. Under Aim 2, we propose to create a new conditional APP transgenic model through co-injection/co-integration using the cumate-repressible system to control APPswe/ind expression. No mouse model utilizes the cumate-repressible system in the brain and simply having the APP transgene under this alternatively conditional system positions this model for use in studies to identify interactions between APP and tau, ?-synuclein or other potential interactors. Finally, under Aim 3, we will crossbreed the new, single allele, tetracycline-repressible tau model with the single allele, cumate- repressible APP to allow the dissection of the interaction between tau (tauopathy) and APP (amyloidosis) in a sequential and systematic fashion. This innovative model, requiring a cost-effective, single breeding, permits independent control of both the tau and APP transgenes and will position the field to fill critical gaps in knowledge that no existing animal model in the AD arena currently allows.

Genetic, pathological, modeling and human biomarker studies all demonstrate that alterations in the tau protein are tightly linked to neurodegeneration in diverse tauopathies including, but not limited to, Alzheimer?s disease (AD) and fronto-temporal dementia (FTD). Tau-inclusion pathology, generically referred to as tauopathy, correlates with cognitive decline and neuronal loss in primary tauopathies and AD. In model systems, expression of FTD-linked tau mutations can lead to tau inclusion pathology, cellular dysfunction and neurodegeneration. As the tauopathy arises, post-translational modifications of tau appear, but in many instances, it is unclear if these modifications are markers of dysfunction or drivers of pathology. Prion-like conformational templating occurs in model systems and has been postulated, but not proven, to explain spread of pathology and different clinical syndromes associated with tauopathy. Yet, despite intensive study, the field has developed a limited portfolio of tau-targeting therapies, and many aspects of tau-induced neurodegeneration remain poorly understood. We have recently developed an ex vivo recombinant adeno-associated virus (rAAV) based organotypic brain slice culture (BSC) model of tauopathy that develops widespread mature tau inclusions recapitulating those in human tauopathies by 1 month in culture. We have i) shown by multiple biochemical and histological means that these are mature tau inclusions, ii) observed a relationship between cell death and tauopathy formation, iii) demonstrated the utility of this model for evaluating therapeutic strategies designed to alter tauopathy, iv) demonstrated that effects observed in the BSC studies are predictive of effects in vivo. We now propose three aims that leverage the BSC tauopathy model to increase understanding of the role tau plays in causing cellular dysfunction and to guide future therapeutic discovery: Aim 1. Further characterize and extend the rAAV-based BSC tauopathy model to gain additional insight into mechanisms that regulate tauopathy and tau-induced cellular degeneration. Aim 2. Evaluate known and emerging therapeutic targets and strategies designed to alter the tauopathy itself or tau induced cellular degeneration. Aim 3. Probe mechanisms by which tau induces cellular dysfunction.

Summary Psychological stress and hypothalamic-pituitary-adrenal (HPA) axis dysfunction play a role in many disorders including Alzheimer?s disease (AD), major depression, metabolic syndrome, and sarcopenia. Chronic high levels of stress and elevated corticosteroids are also hypothesized to act as ?accelerants? of many age-associated diseases and phenotypes. Further, numerous studies report an association between increased stress and HPA axis dysfunction with increased rates of cognitive decline and hippocampal and brain atrophy in late-life dementia. Our interest in the HPA axis stemmed from rodent model data implicating psychological stress, corticotropin-releasing hormone/factor (CRH/CRF), and corticosterone, as factors that impact amyloid and tau pathology and age-associated declines in cognitive function. Indeed, suppression of the HPA axis theoretically represents a unique therapeutic strategy in AD, as it has been implicated in regulating the underlying A? and tau proteinopathies and independently affecting, presumably through corticosteroid excess, brain atrophy and cognitive decline. Unfortunately, testing the role of HPA axis in AD and cognitive aging, has been hindered by the lack of small molecule therapeutics that effectively suppress HPA axis activation in humans. As an alternative to small molecule approaches, we have successfully developed a picomolar affinity IgG1 monoclonal antibody (mAb) targeting CRF (anti-CRF mAb, CTRND05) that dose-dependently blocks stress-induced increases in corticosterone, and can rapidly reverse select Cushingoid phenotypes in mice overexpressing CRF. Metabolic and immunologic studies reveal numerous effects consistent with long-lasting suppression of the HPA-axis; multi-organ transcriptomic studies shows robust regulation of numerous genes that may mediate the physiologic effects of CTRND05. We hypothesize that passive immunotherapy targeting CRF represents a novel, translatable, therapeutic approach to AD and possibly many other disorders. Through pleiotropic actions, anti-CRF immunotherapy may slow the development of A? and tau pathologies as well as brain atrophy and cognitive decline. In this proposal, we will systematically and rigorously evaluate the therapeutic potential of this anti-CRF immunotherapy in appropriate preclinical models and develop companion theragnostic biomarkers. As CRF is completely conserved between humans and mice, and is present at similar concentrations, positive results from these studies will provide the rationale for testing of a humanized high affinity anti- CRF mAb for therapeutic benefit in humans.

Summary Psychological stress and hypothalamic-pituitary-adrenal (HPA) axis dysfunction play a role in many disorders including Alzheimer?s disease (AD), major depression, metabolic syndrome, and sarcopenia. Chronic high levels of stress and elevated corticosteroids are also hypothesized to act as ?accelerants? of many age-associated diseases and phenotypes. Further, numerous studies report an association between increased stress and HPA axis dysfunction with increased rates of cognitive decline and hippocampal and brain atrophy in late-life dementia. Our interest in the HPA axis stemmed from rodent model data implicating psychological stress, corticotropin-releasing hormone/factor (CRH/CRF), and corticosterone, as factors that impact amyloid and tau pathology and age-associated declines in cognitive function. Indeed, suppression of the HPA axis theoretically represents a unique therapeutic strategy in AD, as it has been implicated in regulating the underlying A? and tau proteinopathies and independently affecting, presumably through corticosteroid excess, brain atrophy and cognitive decline. Unfortunately, testing the role of HPA axis in AD and cognitive aging, has been hindered by the lack of small molecule therapeutics that effectively suppress HPA axis activation in humans. As an alternative to small molecule approaches, we have successfully developed a picomolar affinity IgG1 monoclonal antibody (mAb) targeting CRF (anti-CRF mAb, CTRND05) that dose-dependently blocks stress-induced increases in corticosterone, and can rapidly reverse select Cushingoid phenotypes in mice overexpressing CRF. Metabolic and immunologic studies reveal numerous effects consistent with long-lasting suppression of the HPA-axis; multi-organ transcriptomic studies shows robust regulation of numerous genes that may mediate the physiologic effects of CTRND05. We hypothesize that passive immunotherapy targeting CRF represents a novel, translatable, therapeutic approach to AD and possibly many other disorders. Through pleiotropic actions, anti-CRF immunotherapy may slow the development of A? and tau pathologies as well as brain atrophy and cognitive decline. In this proposal, we will systematically and rigorously evaluate the therapeutic potential of this anti-CRF immunotherapy in appropriate preclinical models and develop companion theragnostic biomarkers. As CRF is completely conserved between humans and mice, and is present at similar concentrations, positive results from these studies will provide the rationale for testing of a humanized high affinity anti- CRF mAb for therapeutic benefit in humans.