Donna M Wilcock - US grants

[unreadable] DESCRIPTION (provided by applicant): This proposal studies microhemorrhages that are associated with Alzheimer's disease (AD). Alzheimer's disease (AD) is a chronic, neurodegenerative disease characterized by extracellular amyloid plaques, intracellular neurofibrillary tangles and neuron loss. There is also a vascular component consisting of amyloid deposition in the vasculature termed cerebral amyloid angiopathy (CAA). Microhemorrhages are frequently observed in association with CAA. We observe an inflammatory response to these microhemorrhages consisting of activation of microglia and astrocytes. While the amyloid plaques and neurofibrillary tangles have been, and continues to be, extensively studied, the vascular component of AD remains relatively understudied. The aim of this research proposal is to determine the sequence of events leading to microhemorrhage. We will approach this by using two transgenic mouse models, the APPSwDI/ApoE4 and the APPswe/NOS2-/-. These models are particularly useful since the APPSwDI/ApoE4 mouse develops CAA but does not develop any microhemorrhages while the APPswe/NOS2-/- mouse develops only moderate CAA, but multiple microhemorrhages. We will use immunohistochemical and molecular methods to establish a time-course of pathology and gene expression. We will then manipulate these mice using anti-inflammatory compounds to reduce inflammation and also lipopolysaccharide to induce more inflammation. We will perform these studies in young mice, prior to amyloid deposition, and old mice, with significant amyloid deposition, and will assess any changes in pathology or gene expression. This will assist us in determining the relationship between vascular amyloid and inflammation in the development of microhemorrhages and breakdown of the neurovascular unit in Alzheimer's disease. Spatial memory testing using the radial-arm water maze will also be performed in the anti-inflammatory study to determine the functional consequence of these vascular changes. Overall, the studies to be performed in this research proposal will advance the understanding of the causes of microhemorrhage and the role of the neurovascular unit in Alzheimer's disease. [unreadable] [unreadable] [unreadable] [unreadable]

DESCRIPTION (provided by applicant): Microhemorrhages and vasogenic edema are pathological phenomena that occur in both cerebrovascular disease (CBVD) and Alzheimer's disease (AD). In CBVD these can occur throughout the brain, yet are most frequently subcortical. In AD they usually occur at sites of vascular amyloid deposition. Given that CBVD and AD are not always mutually exclusive but often co-exist it is important that we understand the mechanisms of microhemorrhages and vasogenic edema. We hypothesize that inflammatory-mediated activation of matrix metalloproteinases leads to degeneration of tight junction proteins and basement membrane proteins resulting in vascular leakage producing microhemorrhages and/or vasogenic edema. Our goal for this proposal is to model CBVD in mouse models of amyloid deposition to produce vasogenic edema and microhemorrhage and determine the role of the MMP system in their onset and the impact CBVD has on response to amyloid-targeted therapies. We will assess inflammatory changes and activation of the MMP systems as mechanisms for these abnormalities. Importantly, we propose to acquire MR FLAIR and Susceptibility Weighted (SWI) images to assess vasogenic edema and microhemorrhage as well as any other brain changes occurring through the course of the studies. Immediately prior to tissue harvest we will acquire arteral spin label (ASL) scans to measure brain perfusion and thus enable a comparison of the density of microhemorrhages and brain health. Additionally, we will acquire contrast enhanced T1-weighted scans following administration of Magnevist and Galbumin contrast agents to assess vascular leakage. We propose to use AAV and pharmacological agents to inhibit MMPs directly, or inhibit the inflammatory signals thought to be increasing MMP activity. We will also examine whether the efficacy and side-effect profile of two A¿- targeted therapies in trials are influenced by the presence of CBVD in amyloid-depositing mice. The overall goal of our proposal is to determine the time-course of CBVD pathology when we generate CBVD in APP/PS1 transgenic mice, determine the roles of inflammation and MMPs in the generation of microhemorrhage and vasogenic edema, and finally to establish the effect CBVD has on the response to A¿-targeted therapies. We believe that CBVD is common co- morbidity with AD that influences the pathogenesis of AD and response to therapy.

Abstract Vascular contributions to cognitive impairment and dementia (VCID) describes cognitive impairment resulting from cerebrovascular disease or dysfunction. VCID is a frequent co-morbidity with Alzheimer's disease (AD), as well as a single dementia-causing entity. The most common vasculopathy associated with cognitive impairment is cerebral small vessel disease (SVD). It is highly likely that SVD significantly contributes to the clinical manifestation of dementia, and therefore is a viable target for disease-modifying therapies, whether alone or in combination with AD-targeting therapies. One major obstacle for therapeutic development is the lack of biomarkers that are predictive of the presence and course of SVD-VCID. In this proposal we present candidate biomarkers for SV-VCID that will contribute to the consortium. We have identified MRI imaging modalities of 3D FLAIR, ASL, and DTI as our imaging candidate biomarkers. We have also identified IL-12 p70, TNF?, PIGF and VEGFD as our candidate fluid biomarkers that discriminate SVD well in the subset of our cohort that we have analyzed. In this application we have a plan for developing our candidate biomarkers and validating them through the UH2 phase an individual research group, and also through the UH3 part as a member of the consortium. In addition, we bring significant strengths that will help synergize and move the consortium as a whole forward in our collective goal of developing biomarkers that are ready for large scale clinical trials and FDA qualification in years 6-7 of the consortium. These strengths include a well characterized, longitudinal cohort supported through our ADC and other NIH initiatives, our long history of active participation in consortia providing the experience and infrastructure needed to ensure success in this UH2/UH3 mechanism, our history of data sharing, resource sharing including samples, recruitment of research participants for longitudinal studies, and our foundation in basic and translational science.

Abstract Vascular cognitive impairment and dementia (VCID) is the second leading cause of dementia behind Alzheimer's disease (AD). In addition, VCID is a frequent co-morbidity with AD, complicating the diagnosis and treatment of AD for a significant proportion of AD patients. Despite its prevalence, VCID remains relatively understudied compared to AD, and little is known about the molecular mechanisms underlying the cognitive dysfunction resulting from cerebrovascular disease. In part, this is due to the multiple pathological processes disrupting neurovascular networks that can result in VaD. We have previously shown that astrocytic end-feet are significantly impacted in the presence of cerebral amyloid angiopathy (CAA), with decreased contact of astrocytic end-feet with the vasculature. Further, these morphological changes in the astrocyte were associated with decreased expression of aquaporin 4, Kir4.1 and BK channels at the astrocytic end-feet. We have developed a model of VCID through the induction of hyperhomocysteinemia (HHcy). We have shown that this model in wildtype mice is associated with multiple microhemorrhages, reduced blood flow, neuroinflammation and cognitive impairment. We now have intriguing preliminary data that indicates these same pathological changes in the astrocytes that we observed with CAA also occur in our HHcy model of VCID. In this research proposal we will use the HHcy model of VCID. We will test the hypothesis that astrocyte end-foot disruption contributes to neuronal dysfunction and that the activation of MMP9 in the HHcy model is critical to the disruption of the astrocytic end-feet. We have developed 3 specific aims. Aim 1. Test the hypothesis that astrocytic end-foot disruption leads to neuronal dysfunction and impaired potassium homeostasis. Aim 2. Test the hypothesis that MMP9 is an essential mediator of astrocyte end-foot detachment from the cerebrovasculature with VCID. Aim 3. Test the hypothesis that astrocytic end-foot disruption is a common pathological characteristic of cerebrovascular pathologies of VCID.

ABSTRACT ! The identification of novel therapeutic targets for Alzheimer's disease is necessary to reach the goal of the National Alzheimer's Project Act (NAPA) of having an effective treatment in place by 2025. Despite numerous promising therapeutic approaches identified pre-clinically to treat Alzheimer's disease, the translation of these therapies to the clinic have been incredibly disappointing. The vast number of population genetic studies that have been performed for AD present an opportunity to identify disease pathways what could be targeted therapeutically. One gene that has a strong effect on AD risk is the triggering receptor expressed on myeloid cells-2 (TREM2). As the name implies, TREM2, is an innate immune receptor expressed on microglia, known to signal through DAP12 to trigger phagocytosis. TREM2 SNPs have been identified as significantly increasing risk of AD in GWAS studies. The hypothesis for this increased risk is that there is a loss of function, impairing the innate immune system to clear amyloid deposition efficiently. We hypothesize that targeting TREM2 to activate the receptor will modulate the neuroinflammatory response and stimulate microglia to phagocytose and clear the amyloid deposits. Furthermore, we hypothesize that activating the TREM2 receptor to modulate the neuroinflammatory response will ameliorate tau pathology, provide neuroprotection, and avoid cerebrovascular adverse events associated with A? targeted therapies. To activate the TREM2 receptor, we are using an antibody developed by Alector, LLC, Alector-002a, that recognizes TREM2 and activates the receptor. We have found that the antibody show immune modulation, clearance of amyloid deposits, and cognitive improvement in amyloid depositing mice. We propose three specific aims to test our hypothesis: Specific Aim 1: Determine the neuroinflammatory, amyloid lowering and cognitive effects of A-002a. Specific Aim 2: Determine the tau modifying, neuroprotective and cognitive effects of A-002a. Specific Aim 3: Determine the potential for cerebrovascular adverse events of A-002a.!

ABSTRACT The University of Kentucky Alzheimer's Disease Center (UK-ADC) was founded in 1985, prior to the advent of biomarker initiatives that continue to grow in size and scope. We propose the development of a Biomarker Core to enrich the UK-ADC and provide an infrastructure that will allow us to contribute significantly to the discovery of antemortem biomarkers. The UK-ADC has focused on the early transitions from normal cognitive aging to the development of cognitive impairment. The shift of focus in the AD field to earlier, pre- clinical stages of disease ideally positions our center, which has had a focus on subjects with normal cognition and early detection and tracking of changes associated with degenerative disease states for the last 30 years. As a result, our center has collected over 700 plasma samples, 100 CSF samples, and 250 MRI batteries from cognitively intact individuals. Further, we have over 350 plasma samples, 150 CSF samples and 300 MRI batteries from individuals with mild cognitive impairment. In establishing a biomarker core, we will build an infrastructure that allows us to analyze, distribute and track these valuable current and future biomarker samples. The infrastructure will also provide the means for us to support intramural, extramural, and national biomarker initiatives such as NACC, ADGC/NCRAD, ADNI, ADCS/ATRI and other NIH/NIA initiatives. We will also establish a trial-ready, biomarker-characterized, subject cohort, facilitating enrollment into intramural and extramural clinical translational studies to eliminate recruitment and screen fail bottlenecks. Finally, our center has been at the forefront of research on AD-mimics including hippocampal sclerosis (HS-Aging), primary age- related tauopathies (PART), cerebral age-related TDP-43 and sclerosis (CARTS), and vascular contributions to cognitive impairment and dementia (VCID). As such, the addition of a biomarker core will allow us to continue to contribute to these fields and the rapidly growing interest in biomarker development in these areas. Overall, the bolus of support for our new biomarker core will allow us the increased infrastructure needed to support NIH/NIA initiatives and our researchers needs in the 21st century and beyond.

Abstract Diffuse white matter disease (DWD) is a common manifestation of small-vessel cerebrovascular pathology and a key subtype of vascular contributions to cognitive impairment and dementia (VCID). However, the mechanistic underpinnings of DWD remain incompletely characterized. Based on assessment of extensive data in humans and animal models, we have identified angiogenic mediators, in particular placental growth factor (PlGF), as being strongly associated with diffuse white matter disease. Much like the pathologic angiogenesis that occurs in retinopathies, pathologic angiogenesis in the brain results in blood-brain barrier leakage and, counterintuitively, tissue ischemia. We have exciting preliminary data indicating robust relationships between PlGF and human DWD. We have also identified PlGF as being increased in association with blood-brain barrier leakage. We hypothesize that PlGF, and related angiogenic mediators, result in pathologic angiogenesis, with leaky, tortuous vessels and surrounding inflammation, leading to diffuse white matter disease. Importantly, these pathologic changes also represent a potentially targetable mechanism to improve cognition in aging. To test these hypotheses, we propose focused studies in an extensively characterized human cohort, and a mouse model of small vessel disease. We answer the ?what, where, why? questions surrounding PlGF. ?What? cell type is responsible for PlGF; ?where? is PlGF being expressed; ?why? is PlGF upregulated and can it be modulated. To test these hypotheses, we propose focused studies in an extensively characterized human autopsy cohort, and a mouse model of small vessel disease: Specific Aim 1: Determine contributions to plasma PLGF, and related angiogenic proteins, using cell- specific exosomes and their association with periventricular and deep white matter pathologies. Specific Aim 2: Ascertain the regional expression of PLGF, and related angiogenic proteins, within, adjacent to, and distant from, periventricular and DWD and the association with aberrant angiogenesis. Specific Aim 3: Test the potential to manipulate PLGF related small vessel pathology in response to hyperhomocysteinemia (HHcy)-induced small vessel disease.

Project Summary/Abstract: Biomarker Core The theme of our UK-ADRC is Transitions from normal to late-life multi-etiology dementia, and the role of the Biomarker Core is to provide data and support efforts to develop biomarker profiles for the spectrum of underlying pathologies that can contribute to an individual?s cognitive decline. The Biomarker core will provide critical characterization of our cohort during their cognitively normal state, and through their cognitive transitions. The utility of biomarkers is expanding rapidly, as the dementia field identifies potentially disease- modifying therapies. Rather than focusing on a single biomarker modality (i.e. MRI, PET, plasma etc.), we have adopted a multimodal approach to biomarker characterization. Because our center is particularly interested in multi-etiology dementia, the most common dementia in the normal aging population, we believe a multimodal approach to biomarkers will yield novel insights into the progression of such complex dementias. We propose to measure blood- and CSF-based biomarkers for AD, cerebral small vessel disease (cSVD), large-vessel ischemic disease, and inflammation. In addition, we will perform state-of-the-art MRI imaging incorporating biomarkers of AD, cSVD and neuroinflammation. We will also explore the utility of wearable devices to collect digital biomarkers tracking sleep and physical activity, especially given that Lewy body pathology can lead to early sleep disturbances. Finally, digital gait assessment will provide physical biomarkers of gait, which has been shown to decline early in individuals with cSVD and Lewy body dementia. Importantly, the Biomarker Core has been established for several years and is fully integrated within the UK-ADRC, working closely with the other cores to maximize the utility of the biomarker data collected to date. We will continue to support internal and external research projects on biomarkers, and will also contribute significantly to national and international consortium efforts to develop clinic-ready biomarkers for AD, VCID, and other underlying causes of dementia. Our specific aims are: Aim 1: Collect bi-annual blood-based biomarkers of AD, cSVD, large vessel disease, and inflammation. Aim 2: Collect baseline MRI scans and accompanying CSF ATN biomarkers on all cognitively normal participants in the longitudinal cohort. Aim 3: Fully characterize biomarkers on all participants at their clinical transition from cognitively normal / preMCI to MCI, and from MCI to dementia. Aim 4: Determine the utility of digital biomarkers including activity, sleep, and gait, in predicting cognitive decline and / or brain pathology. Aim 5: Contribute to national efforts to establish, harmonize, and standardize biomarkers including NACC, ADNI, and NCRAD. Aim 6: Integrate with the other cores of the UK-ADRC.

ABSTRACT The MarkVCID consortium was established to discover and cross-site validate biomarkers of cerebral small vessel disease (cSVD) with an ultimate goal of developing a toolbox of biomarkers that will have diagnostic, disease stratification, and longitudinal tracking utility for future vascular contributions to cognitive impairment and dementia (VCID) clinical trials. The University of Kentucky (UK) was selected as one of the seven MarkVCID sites in its initial funding period in 2016. Being in the heart of the stroke belt, Kentucky is a state with a high prevalence of cardiovascular and cerebrovascular disease, and the University of Kentucky is a Center of Excellence for Stroke and Dementia, with UK being a designated Comprehensive Stroke Center and has an NIA Alzheimer's Disease Research Center (ADRC). During our current funding period, we successfully recruited a cohort of 126 individuals (exceeding our originally proposed 120) with varying levels of cardiovascular risk factors and a large proportion of whom have defined subjective memory complaints (SMCs), with some defined as mild cognitive impairment (MCI). All participants underwent the MarkVCID MRI battery, blood collection, and neuropsychological and clinical assessment, while one quarter also contributed CSF. Importantly, all participants have consented to autopsy; a requirement we initiated at the beginning of our MarkVCID recruitment. UK MarkVCID has fully participated in the validation of every biomarker kit except the OCT-A kit. We have also led two biomarker kits: the White Matter Growth and Regression kit and the CSF PlGF kit. In this renewal connected to UH3NS100606 under RFA-NS-16-020, we propose to expand our cohort to 200 individuals, with a particular focus on expanding recruitment of diverse populations and individuals with SMCs and MCI. Having participated in the harmonization, instrumental validation, and now biological validation, of all MRI and fluid biomarker kits, we are poised to make significant contributions in the continuation of the consortium. We have proposed three Specific Aims to achieve the goals laid out in RFA- NS-21-005: Specific Aim 1: Retain and expand a diverse cohort enriched for individuals with subjective memory complaints and cognitive impairment at high risk for cerebral small vessel disease. Specific Aim 2: Work with the consortium to facilitate data, imaging, and fluid sharing and accelerate our validation of the MarkVCID candidate biomarkers in our cohort. Specific Aim 3: Fully engage in leadership roles within the consortium and serve in a consulting capacity for both internal and external researchers seeking to explore biomarkers and or develop new clinical trials and interventional studies for the treatment of VCID.