Peter T. Nelson, MD - US grants

Small regulatory RNAs participate in many eukaryotic cell functions, microRNAs (miRNAs), the major subclass of small regulatory RNAs in animal species, regulate gene expression post-transcriptionally by destabilizing and/or reducing the translation of specific 'target' mRNAs. Post-transcriptional gene regulation has revolutionary implications, yet very little is known of the roles played by miRNAs in neurons or neurodegenerative disease. AIM 1: CHARACTERIZE THE POLYRIBOSOMAL miRNP IN NEURON-LIKE CELLS. miRNA-related biochemistry is poorly understood. We hypothesize that miRNA-containing polyribosomal ribonucleoprotein complexes (miRNPs) represent the biochemical substrate for miRNA:mRNA regulation. We will partially purify the polyribosomal miRNP from Weri retinoblastoma cells, to characterize the biochemical properties and the protein components of this important particle. AiM 2: IDENTIFY AND CHARACTERIZE miRNA:mRNA PAIRS. Although hundreds of human miRNAs are known, most mRNA targets are unknown. We discerned "rules" that govern miRNA:target mRNA interaction. Using these guidelines our bioinformatician collaborators predict mRNA targets regulated by human miRNAs. We will use cell biological tools to verify hypothesized miRNA-mRNA partners relevant to human neurological diseases. AIM 3: CHARACTERIZE A miRNA INTERACTION THAT MAY REGULATE THE EXPRESSION OF ALPHA-SYNUCLEIN (A-SN). On the basis of preliminary evidence, we hypothesize that an evolutionarily conserved sequence element in the 3'-untranslated region of A-SN mRNA is recognized by a specific miRNA (miR-93). A-SN protein plays a central role in some neurodegenerative diseases and its regulation by a miRNA would have important implications in neurobiology, neurodegenerative disease, and RNA biology. We will study this interaction using neuronal cell lines, as a prototype of miRNA:mRNA validation. We will also extend the analyses to human brain tissue in health and disease.

[unreadable] DESCRIPTION (provided by applicant): Abstract MicroRNAs (miRNAs) are recently-discovered small regulatory RNAs that play fundamental roles in neurobiology. Preliminary results indicate that decreased expression of a particular miRNA, miR-107, may contribute to Alzheimer's disease (AD) pathogenesis through a metabolic pathway. These are the first published data pertaining to miRNAs in a specific pathway that may contribute to AD. We will test a specific strategy to target this pathway for AD therapy. Hypothesis #1: MiR-107 expression is decreased very early in AD, which increases BACE1 expression, and hence increases the amount of neurotoxic Abeta peptides in AD patients' brains. Hypothesis #2: Bezafibrate treatment decreases AD-type pathology by increasing levels of miR-107. Specific Aim #1: Characterize fully the regulation of BACE1 by miRNAs. Sub-Aim a. A novel technique will test directly whether BACE1 mRNA is a miRNA target. This biochemical approach involves co- immunoprecipitation using our monoclonal anti-Argonaute antibody. Sub-Aim b. Tissue culture studies will be performed to evaluate exactly which parts of the BACE1 mRNA 3'UTR constitute miRNA targets. Sub-Aim c. `Knock-in' and `knock-down' techniques will be used to alter miR-107 levels specifically in human cultured cells, to determine the effects of miR-107 expression changes on the levels of BACE1 protein, C99 polypeptide, and A2 peptide. Experiments will be performed initially on H4 and SH-SY5Y cells. Specific Aim #2: Characterize the impact of miR-107 on glucose metabolism and correlate the expression of miR-107 and other miRNAs with AD pathology in situ Sub-Aim a. Tissue culture studies will be performed to assess how pharmacological treatments that alter metabolism affect miR-107 expression, and to evaluate how cellular changes in miR-107 influence the levels of specific metabolic intermediaries. Sub-Aim b. Human brain in situ hybridization will be used to understand how miR-107 expression relates to pathological hallmarks of AD and non-AD dementia. Specific Aim #3: Evaluate bezafibrate for increasing miR-107 levels and decreasing BACE1 protein and A2 peptide(s) formation in vitro and in vivo. Bezafibrate is an orally-administered, well-tolerated medication. Sub-Aim a. Preliminary results in cultured cells demonstrated that bezafibrate causes increased miR-107 expression and also induced down-regulation of BACE1 protein. The specific mechanism of bezafibrate action will be characterized using experiments in which the levels of miR-107 are manipulated. Sub-Aim b. Bezafibrate will be administered to mice - APPNLh/NLh x PS1P264L/P264L humanized APP knock-in mutants - that are an excellent model of AD-type amyloidogenesis (1), to demonstrate in vivo the efficacy of bezafibrate in modulating miR-107, BACE1, A2 levels, and AD-type neuropathology. PUBLIC HEALTH RELEVANCE: MicroRNAs are recently-discovered molecules that serve fundamental functions in the human brain. This research demonstrates for the first time that a particular microRNA may play an important role in Alzheimer's disease. A research program is proposed which exploits this new discovery, in order to develop and evaluate a novel therapy for patients at risk for Alzheimer's disease. [unreadable] [unreadable]

DESCRIPTION (provided by applicant): We hypothesize that microRNAs (miRNAs) play important roles in the human brain during healthy aging and in Alzheimer's disease (AD). MiRNAs are small RNAs that regulate gene expression. Most miRNAs act through hybridization with "target" mRNAs. We and others have observed an altered pattern of miRNA expression in AD brain tissue. In various models where miRNAs are reduced, neurodegeneration ensues quickly. The mechanisms of miRNA-mediated neuroprotection and neurodegeneration are poorly understood, partly because most of the mRNA targets of miRNAs are still unknown. Unfortunately, there has been no suitable technique to indicate experimentally which mRNAs are miRNA targets. We developed a high-throughput assay to identify miRNA targets in human brain tissue. Here we propose to use this novel assay to better understand the neurochemistry of AD. Our research program has the following Specific Aims: 1. Obtain brain tissue from the University of Kentucky Alzheimer's Disease Center Brain Bank that is thoroughly characterized including clinical evaluations near death, short post-mortem intervals, and state-of-the-art neuropathology. Clinical cohorts will include brain tissue of non- demented controls, mild cognitive impairment controls, AD, and non-AD dementia controls. 2. Optimize a novel biochemical assay for accurate, specific, and direct miRNA target identification. This assay, the Co-immunoprecipitation MicroRNA Assay Procedure (CoMAP), has been optimized in cell culture and preliminarily in brain tissue. CoMAP will be performed on the brain tissue described in Specific Aim #1. 3. Analyses of CoMAP data will incorporate data from mRNA microarray, miRNA microarray, clinical data, and pathological data referent to the same specimens. These analyses will focus on discovering miRNA targets relevant to AD treatment and diagnosis, and on elucidating the mRNA targets that subserve the neuroprotective functions of miRNA. The raw and analyzed datasets, and the CoMAP assay itself, will be shared freely with other investigators. These Specific Aims are intended to answer the following fundamental questions: 7 What mRNAs are miRNA targets in healthy brain aging? 7 What mRNAs are miRNA targets in Alzheimer's disease and other altered brain states? 7 How do changes in mRNA targets correlate with changes in expression of miRNAs? PUBLIC HEALTH RELEVANCE: The objective of this project is to use a novel technique to better understand the causes of Alzheimer's disease and why some people remain Alzheimer's disease-free during aging. We will characterize in human brains a newly-discovered high impact level of gene regulation, which are called microRNAs, using a method called a Co-immunoprecipitation MicroRNA Assay Procedure (CoMAP). We think that we can produce information that directly or indirectly contributes to diagnostics and therapeutics for Alzheimer's disease patients.

DESCRIPTION (provided by applicant): The University of Kentucky proposes to acquire an Aperio ScanScope(R) XT digital slide scanner including the ImageScope"/Genie" and Webscope" viewing software. This instrument will be housed in the University of Kentucky Alzheimer's Disease Center Neuropathology Core laboratory. The location is safe and secure, but open to all the Major and Minor Users, with outstanding Institutional Support. 11 Major Users and 3 Minor Users, representing ten different academic departments within the University, strongly desire the instrument. There is no analogous instrument currently available within or nearby the University of Kentucky;however, this scientific advancement dovetails very well with existing medical expertise, technical infrastructure, and research facilities at the University of Kentucky. The Aperio ScanScope XT scans and analyzes microscope slides in a digitized format that will enable optimized and detailed archiving and data mining of histopathological data. The instrument represents a significant technological step forward for the field of quantitative neuropathology by facilitating the digitized identification and analysis of histopathological hallmarks of ND, in addition to normal structures. In addition, the slide scanner is ideal for improving quantitative measures of surviving cell counts in stereology, in situ hybridization signal quantification, animal model assessments (including brain trauma and prion disease models), and other cutting edge applications that will directly facilitate NIH-funded research projects by Major Users at the University of Kentucky. This instrument will provide a unique opportunity to introduce, validate, and publish methods in digital microscopy and bioinformatics for the purpose of quantifying brain pathology. The instrument will have an Advisory Panel that is broad-based, with representation by eight different academic departments from the University of Kentucky. Finally, due to its web-based functionality, the purchase of the Aperio ScanScope XT will allow for the exchange of data throughout Kentucky's remote regions and through the network of Alzheimer's Disease Centers nationally.

DESCRIPTION (provided by applicant): The miR-15/107 miRNA group are paralogous microRNAs (miRNAs), with overlapping gene regulatory impact, that are downregulated in Alzheimer's disease (AD) brains. Our underlying hypothesis is that miR- 15/107 gene augmentation (up-regulation) will help to reduce brain cellular expression of BACE1 and tau kinases (PKA and CDK5-regulating proteins). We have strong preliminary evidence in support of this hypothesis. The overall goal of the present research proposal is to obtain information necessary to develop future miRNA-based brain therapies and to increase our knowledge about miRNAs' role in AD. Therapeutic strategies must involve either stimulating endogenous miRNA production, or, alternatively, a gene therapy approach with exogenously introduced RNA or viral vectors. The key challenges, before developing brain therapies related to miR-15/107 genes, are 1> to understand upstream stimuli that alter miR-15/107 expression in human brains, and 2> define downstream genes regulated by these miRNAs, including an assessment of the potential for manipulating the off-target effects of miR-15/107-related miRNAs. We thus propose novel experiments in human brain and in primary rat brain-derived cultured cells. Specific Aims for this research project: Specific Aim #1: Define the specific AD-relevant signaling pathways that modulate miR-15/107 gene expression. Aim 1A: Perform hypothesis-based studies in cultured rat primary brain cells anchored in our preliminary results finding that glucose levels and discrete neuroinflammatory stimuli specifically alter miR-15/107 gene expression which may suggest strategies for miRNA-based therapies. Aim 1B: Perform comprehensive miR-15/107 expression profiling in human brain to understand how parameters linked with AD risk correlate with altered miR-15/107 gene expression because miRNA neurochemical studies need to be anchored in human brain data. Specific Aim #2: Define the exact downstream mRNA targets regulated by miR-15/107 genes in primary cultured rat brain cells. Preliminary data indicate that miR-15/107 genes may be a key mechanistic link between metabolic changes and increased tau phosphorylation in human brains. Using methods that were developed and optimized in our laboratory, we will perform comprehensive analyses of miR-15/107 miRNA targets in primary cultured rat brain cells. Specific Aim #3: Manipulate and minimize off-target effects of miRNAs using RNA sequence modifications in primary cultured brain cells. Cultured neurons will be transduced with lentivirus vectors harboring altered sequences related to miR-15/107 genes. We have already generated miRNA expressing lentivirus and transduced primary cultured neurons to help optimize the potential impact of miRNA-based therapies in the brain. The overall goal is to produce reagents with optimal on-target and minimal off-target impact, in order to maximize the potential value of small RNA- based therapeutics.

DESCRIPTION (provided by applicant): Dementia with Lewy bodies (DLB) is a devastating neurodegenerative disease. Cortical Lewy body pathology (LBP), which is the pathological substrate of DLB, is observed in 10%-30% of brains in most autopsy series of dementia patients. At the molecular level, LBP consists of aberrant deposits of alpha-synuclein (alpha-SN) protein and there is evidence that increased alpha-SN gene dosage is seen in some cases of DLB. The biochemical pathways that contribute to LBP are poorly understood and our overall goal is to help fill this knowledge gap. Men have strongly (~three-fold) increased risk for developing autopsy-confirmed cortical LBP compared to women; this is an observation replicated in many autopsy series. Our overarching hypothesis is that a particular microRNA (miRNA; miR-497) contributes to sexually-dimorphic DLB pathogenesis. In preliminary studies we made the following observations: miR-497 is expressed sexually dimorphically in human brain and in rat primary cultured neurons; miR-497 is enriched in human brains with LBP and in LBP- vulnerable brain areas; and, miR-497 expression in cultured cells alters alpha-SN and DJ-1/PARK7 expression. Our lab has expertise in both LBP and miRNAs which enable us to test the hypothesis that miR- 497 regulates alpha-SN expression and may influence LBP in a sexually dimorphic manner. Specific Aim 1: Test the hypothesis that miR-497 is sexually dimorphically expressed in human brain, and dysregulated in human brains with LBP. Proposed studies will represent the state of the art in miRNA profiling using miRNA microarrays to test for associations between miRNA expression and both LBP and gender status. Preliminary data indicate a systematic tendency for sexually dimorphic miR-497 to be dysregulated in brains with LBP and in human brain areas vulnerable to LBP. Specific Aim 2: Test the hypothesis that sexually dimorphic miR-497 regulates alpha-SN expression. Preliminary data indicate that miR-497 regulates alpha-SN. Primary rat neurons will be transduced with lentiviral vectors expressing miR-497 versus other control miRNAs to test the hypothesis that miR-497 regulates alpha-SN. Further experiments in these cells will query whether the regulation of alpha-SN by miR- 497 is direct or via an intermediate regulation of PARK7/DJ-1 gene. Following viral transduction with miR-497 and control miRNAs, we will determine the full list of miR-497 targets in cultured primary neurons. These mechanistic experiments will aid our ultimate goal of therapies to combat this currently untreatable disease. Public health significance: Understanding how sexually dimorphic miR-497 alters alpha-SN expression to induce sex-dimorphic pathology would be a major novel paradigm in neurochemistry with clinical/translational significance for both diagnostic and therapeutic strategies. The primary cel culture system will offer an experimental paradigm for testing novel methods of attenuating the dimorphic expression of miR-497 that drives alpha-SN expression.

DESCRIPTION (provided by applicant): Our preliminary data indicate that miR-107 plays an important role in AD pathogenesis. Fibrates (PPAR agonists) increase miR-107 expression, and down-regulated BACE1 protein, an essential enzyme contributing to AD, in cultured H4 cells. We plan to test our hypotheses and evaluate a potential therapy for Alzheimer's disease (AD) based on this novel microRNA (miRNA) pathway. Preclinical work in this area using animal models of AD has been thwarted by the species-specific hepatotoxicity not seen in humans. Thus, human clinical trials are necessary to test this important hypothesis on the disease modifying properties of fibrates in AD. Specifically, we propose an evaluation of the safety and efficacy of gemfibrozil administration on micro-RNA modulation of AD mechanisms in a parallel-design, double- blind, placebo-controlled study. We will evaluate both safety and target engagement of miR- 107 by gemfibrozil as well as alterations in relevant AD biomarkers. Gemfibrozil is a safe, orally- administered, FDA-approved drug for treatment of hyperlipidemia in aged individuals. The FDA has indicated IND exemption status for these studies. This study is designed to provide the foundation for future large-scale Phase II & III studies of fibrates in AD and AD prevention trials and represents the first attempt we are aware of designed to modulate disease progression in AD through influences on novel micro-RNA pathways. As such the proposed study represents a cutting-edge, data-driven, exploration of a novel disease relevant pathway that may hold promise for our global efforts targeting this major health priority among developing and developed nations.

Project Summary/Abstract: Neuropathology Core The overall objective of the Neuropathology Core of the University of Kentucky Alzheimer?s Disease Center (UK-ADC) is to support research on normal brain aging, presymptomatic Alzheimer?s disease (pAD), mild cognitive impairment (MCI), early and late AD, mixed dementia syndromes, and other dementing disorders. Autopsies will be performed by our Rapid Autopsy Team on longitudinally followed subjects from our Clinical Core. We will perform short post-mortem interval autopsies in relation to our clinical cohort, and we will maintain a high autopsy rate. This Core is optimally tailored to help address important research questions. The Core will provide brain tissue specimens, CSF and synaptosomes for investigators at UK, other ADCs, and outside investigators. The Core will also provide consensus conference determined diagnoses, quantitation of neurofibrillary tangles (NFT), neuritic plaques, and diffuse plaques from 8 brain regions, A? 1-40 and 1-42 quantitation, Braak staging, CERAD, and NIA-Reagan Institute staging on all autopsied cases to investigators. This brain bank has been operating continuously for over three decades with a strong track record, so special care will be taken to ensure diagnostic excellence, consistency, and continuity. The Core will maintain a tissue bank of the above specimens and frozen serum, plasma, buffy coats and CSF from living patients. Special emphasis will be placed on defining the neuropathological findings in the brains of the oldest old (>85 years), and providing investigators with specimens from cognitively intact control subjects with no A? deposition and sparse tau pathology (successful cerebral aging) and also cognitively intact subjects with abundant plaques and neurofibrillary tangles. Providing these samples will contribute to clinical-pathological correlation studies and cutting-edge research that include sponsored studies related to AD genomics, oxidative stress, hippocampal sclerosis, dementia with Lewy bodies, amyloid precursor protein processing, Down syndrome, and neuroinflammation. Frequent consensus conferences will be held with the Clinical Core and Biostatistics Core to help define clinical-pathological diagnoses on all autopsied subjects. This Core is strongly integrated with other Cores of the UK-ADC, and exploits unique opportunities to conduct clinical-pathological correlative studies on longitudinally followed subjects. Through these methods we will better understand normal brain aging and the transition to dementia with the focused goal of contributing to therapeutic or preventive measures. The Neuropathology Core complements the other Cores of the UK-ADC to provide extremely essential diagnoses and tissue samples that are required for many cutting-edge researchers at the University of Kentucky and elsewhere. We will build on our track record of excellence using innovative tools related to brain autopsies, neuropathological diagnoses, tissue banking, and state-of-the-art clinical-pathological correlation.

? DESCRIPTION (provided by applicant): Diseases that mimic Alzheimer's disease (AD) are understudied causes of cognitive impairment in the elderly. Poor understanding of these diseases has hampered AD clinical trials while leaving important illnesses largely unaddressed from a clinical research perspective. A common and high-morbidity AD mimic is hippocampal sclerosis of aging (HS-Aging). HS-Aging is characterized by cell loss and astrocytosis in the hippocampus, with phosphorylated TDP-43 (P-TDP-43) pathology, not correlated with AD-type pathology, nor with APOE genotype. HS-Aging affects 10-25% of persons above age 85 years. The PI of the current proposal has studied HS-Aging extensively, including the first HS-Aging genome-wide association study (GWAS). A genetic polymorphism in the ABCC9 gene is linked to HS-Aging pathology. Importantly, we recently (Jan 2015) published a paper that replicated this observation in a separate group of research volunteers. The ABCC9 mutation enables us to address a central as-yet unrealized promise of genomics studies: clinical relevance. Remarkably, the GWAS-identified HS-Aging risk gene ABCC9 is a druggable target-both agonist and antagonist drugs are used widely in humans. In a prior published study, we found that exposure to sulfonylureas (oral anti-diabetic drugs that antagonize ABCC9 protein function) is associated with increased risk for HS-Aging pathology in humans, controlling for other factors. We need to assess the potential to target ABCC9 in a preclinical model for more rigorous control of experimental parameters. That will enable us to test the impact of an ABCC9 agonist drug, with the opposite effects of sulfonylureas, as a potential therapy for clinical HS-Aging. Overall Hypothesis: Pharmacologic ABCC9 regulation provides a therapeutic strategy for HS-Aging. We propose proof-of-concept preclinical studies to test the specific hypothesis that ABCC9 agonist nicorandil attenuates pathologic and behavioral features of HS-Aging in a mouse model. Specific Aims: 1. Characterize the first preclinical model of HS-Aging. In GRN knockout (GRN-KO) mice, our studies indicate the presence of brain changes that model features of human HS-Aging, including hippocampal P-TDP-43 pathology and hippocampus-related neurobehavioral deficits. 2. Based on studies in humans, test in the GRN-KO mouse model the hypothesis that a sulfonylurea drug (glimepiride) which antagonizes ABCC9, exacerbates HS-Aging pathology and abnormal behavior. 3. Test in the GRN-KO mouse model the hypothesis that nicorandil, which opens the potassium channel (the opposite activity as sulfonylureas), reduces HS-Aging-related abnormal pathology and behavior. Since there are similar pathologies and genetic susceptibilities, the therapeutic strategy may also be relevant to a separate lethal neurodegenerative disease, frontotemporal lobar degeneration (FTLD).

Hippocampal sclerosis of aging (HS-Aging) is a major pathologic substrate of dementia but there currently are no validated strategies in the clinical setting to diagnose or treat the disease. HS-Aging affects ~15% of elderly persons and is associated with substantial cognitive impairment. Our group has studied this area extensively, leading to the following major hypothesis: thyroid hormone (TH) dysregulation contributes to HS-Aging pathogenesis. This novel pathogenetic mechanism may provide the basis to diagnose HS- Aging during life using CSF analyses, and to develop a therapeutic strategy. However, critical knowledge gaps remain in terms of characterizing the specific association between TH dysfunction and brain pathology, and the potential to target the mechanism for therapeutic purposes. We propose a research program to fill these knowledge gaps while testing key hypotheses via the following Specific Aims: Hypothesis 1: Clinical TH status is associated with presence and severity of HS-Aging pathology. Specific Aim 1: Test the hypothesis in a convenience sample (n=205, including cognitively intact and diverse non-HS-Aging dementia controls) from the University of Kentucky AD Center biobank. We will apply rigorous, quantitative digital pathologic methods to assess TDP-43 pathology, AD plaques/tangles, and ?- synucleinopathy for correlation with clinical TH status: self-reported TH disease and TH medications are well- documented. As expected in aged persons, more than 25% of the subjects exhibited clinical TH dysfunction. Hypothesis 2: CSF TH levels are associated with HS-Aging pathology and may provide a novel biomarker. Specific Aim 2: Evaluate TH (triiodothyronine, or T3) in CSF as a clinical biomarker of HS-Aging. We will assess human CSF TH levels with direct correlation with various subtypes of pathology. We also will test TH in clinical CSF from lumbar punctures, correlated with established AD-related biomarkers (A? and tau) and HS-Aging SNPs, with the goal of developing a new method to diagnose HS-Aging in living persons. We have obtained CSF from autopsied individuals (n=104) and clinical CSF samples (n=195) to accomplish this Aim. Hypothesis 3: Specific HS-Aging risk-associated gene variants induce altered brain TH levels with extensive impact on brain gene expression, and orally available drugs can alter this pathogenetic mechanism. Specific Aim 3: Define gene expression changes relevant to TH and HS-Aging. We will analyze human genomics databases to define how gene changes linked to HS-Aging risk contribute to variability in ABCC9 and SLCO1C1 (a major brain TH transporter) expression. We will test human cells (cultured human hESC astrocytes and lymphoblastoid cells transformed with DNA from people with known genotypes and pathology) to determine the potential for manipulating the levels of ABCC9, of TH transporter SLCO1C1, and of other TH- regulated genes. Finally, in mice, we will test how TH-responsive gene expression, neuropathology, and neurobehavior are affected in vivo by treatment with TH and/or the ABCC9 agonist drug glimepiride.

DESCRIPTION (provided by applicant): Alzheimer's disease (AD) manifests severe pathological changes in the CNS including increased levels of amyloid, hyperphosphorylated tau, and synaptic loss. Synaptic dysfunction is a hallmark of the disease that associates with the cognitive ability and level of dementia during the progression of AD. It is unclear why synaptic numbers are reduced in the early stages of AD and how it is linked to other features of the pathology. We believe that oxidative damage and microtubule/actin changes are early events in the progression of AD and underlie synaptic dysfunction. Increasing evidence suggests that the medial temporal lobe (MTL) is the earliest regions of the brain affected and may provide important clues to the progression of the disease. Our hypothesis is that multiple different cellular changes occur in the MTL initiating the loss of synaptic plasticity resulting in a declinein cognition and the onset of clinical AD. The proposed experiments will evaluate changes in this brain region in regards to synaptic proteins, oxidative stress, and structural proteins. Studies ar carried out on short post mortem samples from longitudinally followed individuals with detailed cognitive testing. Individuals with amnestic mild cognitive impairment (aMCI) will be compared to individuals that clinically show no cognitive impairment (NCI). The NCI group is further classified as individuals with very low pathology (LP- NCI) or high (AD levels) of histopathology (HP-NCI). Current literature suggests that HP-NCI represents individuals with preclinical AD. Aim one assess the direct relationship between different key synaptic proteins and oxidative stress in the MTL. Aim two probes whether or not NADPH-oxidase (NOX) activity and its subunits change during the disease progression and how it associates with changes in synaptic proteins and soluble A beta. The NOX enzyme is normally expressed throughout the central nervous system and is a key non-mitochondrial source of free radicals. The third aim explores whether or not key cytoskeletal proteins, such as the actin binding protein cofilin and tau, increase in the MTL and alters different levels of key synaptic proteins. Successful completion of the proposed studies will reveal new insights into the mechanisms underlying the very early stages in the progression of AD and contribute to the development of rational therapies.

Abstract The proposed project is a pilot clinical trial investigating a potential treatment for hippocampal sclerosis of aging (HS-Aging). A major subtype of ?Alzheimer's disease and related dementia? (ADRD), HS-Aging affects 10-25% of all elderly individuals. HS-Aging is typically misdiagnosed as Probable AD or AD-type dementia in the clinical setting. Unfortunately, there currently is no validated biomarker to diagnose HS-Aging during life, and there is no known therapy. We will test the safety and efficacy of nicorandil for HS-Aging, based on our prior work elucidating a pharmacologically targetable mechanism underlying the disease. Nicorandil is a vasorelaxant drug, used clinically to treat chronic heart failure in the elderly population. Pharmacologically, Nicorandil is an agonist for a protein (SUR2) that is encoded by a gene that we found to be linked to HS-Aging risk. Primary specific aims follow: Specific Aim #1: Evaluate safety and neurodegenerative biomarkers linked to HS-Aging pathology in nicorandil vs. placebo treated subjects by: a. Conducting a double-blind, randomized, placebo-controlled, clinical trial of nicorandil in 62 participants (both sexes, >75 years old, CDR 0.5 or 1, with HS-Aging profile in CSF and MRI biomarkers [amyloid and phospho-tau negative, with evidence for hippocampal atrophy; A-/T-/N+]) over a 96-week treatment period; b. Evaluating the safety of nicorandil administration in the elderly at risk for HS-aging (this is the primary outcome measure) that will inform future trial design; and, c. Measuring structural MRI (3D-T1; hippocampal atrophy is the main efficacy outcome measure), cognitive tests, and CSF levels of nicorandil, tau, phospho-tau, and A?(1-42) at baseline and week 96. Specific Aim #2: Optimize and further explore HS-Aging biomarkers by: a. Refining MR imaging analysis (including hippocampal volumetric assays, arterial spin labeling (ASL), diffusion tensor imaging (DTI), magnetic resonance spectroscopy (MRS) techniques that may distinguish participants with probable HS-Aging from those with positive AD biomarkers; b. Performing proteomic discovery analysis in CSF to identify and evaluate potential HS-Aging biomarkers to complement the A/T/N framework utilizing our prospective cohort with A?(1-42), phospho-tau, and neurodegeneration markers and MR imaging as a control cohort for AD. This specific aim will directly test and enhance the clinical utility of the A/T/N framework for diagnosis of degenerative disease state; and, c. Following our published and replicated neurocognitive testing marker that is associated with HS-Aging pathology, we will optimize the clinical and neurocognitive criteria for disease diagnosis based on the prospects of a relatively long-running (96 week) early-phase clinical trial.

The heterogeneous pathologies of Alzheimer's disease and related dementias (ADRD) are still incompletely understood. There is no perfect animal model to study these diseases. Four known aberrantly misfolded proteins are commonly detected via neuropathologic examination of brains with ADRD: A?, Tau, TDP-43, and/or ?-Synuclein. Our preliminary data indicate that there are more pathogenic protein species awaiting identification. Characterization of these proteins may be relevant to the development of both diagnostic and therapeutic strategies for ADRD. The goals of this research project are to identify previously uncharacterized, misfolded, and aberrantly processed proteins in ADRD; to resolve gene variants that modulate the severity and heterogeneity of dementia through the novel misfolded proteins; and, to perform clinical-pathological correlation, focusing on these novel proteins, to identify new disease-associated pathologic biomarkers. We will leverage the resources of the University of Kentucky AD Center (UK-ADC) biobank and the University of Kentucky Proteomics Core Facility, to execute the following Specific Aims: Specific Aim 1. Analyse detergent-insoluble protein extracts from human amygdala (snap-frozen at autopsy) to investigate whether as yet uncharacterized misfolded proteins are detectable in ADRD. Polypeptides from the detergent-insoluble, urea-soluble protein fractions of amygdala will be interrogated using mass spectrometry. We have on-hand amygdalae from 40 UK-ADC subjects which incorporate a spectrum of clinical and pathologic features. Immunohistochemistry and biochemical studies will be performed to determine the best candidate proteins for additional studies (Aims 2 and 3). Specific Aim 2. Construct a robust and harmonized database with exonic sequencing to localize genetic regions associated with novel misfolded proteins in ADRD. We will test the association between dementia and rare, exonic (`mis-sense') genetic variants in genes that encode candidate misfolded proteins (Aim 1). Genetics data augmented with rich neuropathologic endophenotypes and longitudinal clinical data will enable insights into novel mechanisms that drive dementia. Large-scale datasets (NACC, ADGC, ADSP) will be aggregated and harmonized to test the genetic drivers of clinical and neuropathology-based endophenotypes focusing on novel candidate genes. Candidate target genes have already been identified. Specific Aim 3. Establish the clinical-pathologic correlation for the novel misfolded proteinopathies in ADRD. We will test the association between the potential novel proteinopathies (from Aim 1) with cognitive impairment, factoring in known markers A?, tau, ?-Synuclein, and TDP-43, as well as cerebrovascular pathologies. We have 370 samples available for analyses (both sexes) from the UK-ADC, which should be statistically powered to test our hypothesis that the presence and severity of novel misfolding protein pathologies are associated with cognitive impairment.

Project Summary/Abstract: Neuropathology Core The overall objective of the Neuropathology Core of the UK-ADRC is to support research on normal brain aging, presymptomatic AD, MCI, early and late AD, mixed dementia syndromes, and other dementing disorders. Autopsies will be performed by our Rapid Autopsy Team on longitudinally followed subjects from our Clinical Core. We will perform short post-mortem interval autopsies, and we will maintain a high autopsy rate. This Core is optimally tailored to help address important research questions. The Core will provide brain tissue, CSF and other biospecimens for investigators at UK, other ADRCs, and outside investigators. The Core will also provide consensus conference determined diagnoses, quantitation of neurofibrillary tangles, neuritic plaques, and diffuse plaques from 8 brain regions, Ab quantitation, Braak staging, CERAD, and NIA-Reagan Institute staging on all autopsied cases, along with evaluation of alpha-synuclein and TDP-43 proteinopathy. This brain bank has been operating continuously for over three decades with a strong track record, so special care will be taken to ensure diagnostic excellence, consistency, and continuity. The Core will maintain a tissue bank of the above specimens and frozen serum, plasma, buffy coats and CSF from living patients. Special emphasis will be placed on generating rigorous quantititative pathologic metrics from digital pathology, and providing investigators with specimens from cognitively intact control subjects with no Ab deposition and sparse tau pathology (successful cerebral aging) and many cases with mixed pathologies. Providing these samples will contribute to clinical-pathological correlation studies and cutting-edge research that include sponsored studies related to AD genomics, oxidative stress, hippocampal sclerosis/LATE, dementia with Lewy bodies, Down syndrome, and neuroinflammation. Frequent consensus conferences will be held with the Clinical, Biomarker, and Data Management and Statistics Cores to help define clinical-pathological diagnoses on all autopsied subjects. The Neuropathology Core is strongly integrated with other Cores of the UK-ADRC, and exploits unique opportunities to conduct clinical-pathological correlative studies on longitudinally followed subjects. Through these methods we will better understand normal brain aging and the transition to multi- etiology dementia with the goal of contributing to therapeutic or preventive measures. The Neuropathology Core complements the other Cores of the UK-ADRC to provide extremely essential diagnoses and tissue samples that are required for many cutting-edge researchers at the University of Kentucky and elsewhere. We will build on our track record of excellence using innovative tools related to brain autopsies, neuropathological diagnoses, tissue banking, and clinical-pathological correlation. Our specific aims are: Aim 1: Provide state-of-the-art neuropathological and biospecimen repository services Aim 2: Leverage neuropathology resources and expertise to contribute to research efforts Aim 3: Integrate with other cores to contribute to administrative, research and educational missions

Abstract The proposed project is a pilot clinical trial investigating a potential treatment for hippocampal sclerosis of aging (HS-Aging). A major subtype of ?Alzheimer's disease and related dementia? (ADRD), HS-Aging affects 10-25% of all elderly individuals. HS-Aging is typically misdiagnosed as Probable AD or AD-type dementia in the clinical setting. Unfortunately, there currently is no validated biomarker to diagnose HS-Aging during life, and there is no known therapy. We will test the safety and efficacy of nicorandil for HS-Aging, based on our prior work elucidating a pharmacologically targetable mechanism underlying the disease. Nicorandil is a vasorelaxant drug, used clinically to treat chronic heart failure in the elderly population. Pharmacologically, Nicorandil is an agonist for a protein (SUR2) that is encoded by a gene that we found to be linked to HS-Aging risk. Primary specific aims follow: Specific Aim #1: Evaluate safety and neurodegenerative biomarkers linked to HS-Aging pathology in nicorandil vs. placebo treated subjects by: a. Conducting a double-blind, randomized, placebo-controlled, clinical trial of nicorandil in 62 participants (both sexes, >75 years old, CDR 0.5 or 1, with HS-Aging profile in CSF and MRI biomarkers [amyloid and phospho-tau negative, with evidence for hippocampal atrophy; A-/T-/N+]) over a 96-week treatment period; b. Evaluating the safety of nicorandil administration in the elderly at risk for HS-aging (this is the primary outcome measure) that will inform future trial design; and, c. Measuring structural MRI (3D-T1; hippocampal atrophy is the main efficacy outcome measure), cognitive tests, and CSF levels of nicorandil, tau, phospho-tau, and A?(1-42) at baseline and week 96. Specific Aim #2: Optimize and further explore HS-Aging biomarkers by: a. Refining MR imaging analysis (including hippocampal volumetric assays, arterial spin labeling (ASL), diffusion tensor imaging (DTI), magnetic resonance spectroscopy (MRS) techniques that may distinguish participants with probable HS-Aging from those with positive AD biomarkers; b. Performing proteomic discovery analysis in CSF to identify and evaluate potential HS-Aging biomarkers to complement the A/T/N framework utilizing our prospective cohort with A?(1-42), phospho-tau, and neurodegeneration markers and MR imaging as a control cohort for AD. This specific aim will directly test and enhance the clinical utility of the A/T/N framework for diagnosis of degenerative disease state; and, c. Following our published and replicated neurocognitive testing marker that is associated with HS-Aging pathology, we will optimize the clinical and neurocognitive criteria for disease diagnosis based on the prospects of a relatively long-running (96 week) early-phase clinical trial.