Alzheimer's disease (AD) is the most common cause of dementia and a major public health problem. Data from genetic, biochemical, animal, and human studies suggest that the amyloid-? (A?) peptide plays a key early role in initiating disease pathogenesis and that the microtubule associated protein tau plays a critical role in neurodegeneration and disease progression. Progressive accumulation of A? in the brain appears to ultimately lead to and exacerbate downstream events directly linked to cognitive decline and dementia such as inflammation and tau aggregation. Prior to this PPG proposal, we found that synaptic and network activity is tightly coupled with the release of the A? peptide in the extracellular space of the brain as part of a normal biological process. Our labs discovered some of the cellular mechanisms that link synaptic transmission and network activity with dynamic changes in A? levels in awake, behaving mice with confirmation in human studies. This collaborative work led to the submission and funding of the current PPG which has been funded from 4/1/12 to the present. We have made substantial progress over the last 4 years. Some key findings are that the sleep/wake cycle regulates A? levels dynamically with A? release being higher during wake and lower during sleep. This effect, at least in part, is via neuronal activity differences between wake and sleep. We also found that A? and tau release by neurons is controlled by synaptic activity and can be monitored dynamically. It was also found that A? levels, clearance, and aggregation can be strongly influenced by neuronal LRP1 and heparan sulfate proteoglycans (HSPG). In addition to our findings, increasing evidence indicates that once key proteins involved in neurodegenerative diseases aggregate in the brain (e.g. A? and tau), they appear to spread from one region to others within neuronal networks that are synaptically connected. There is also growing evidence that in AD, A? aggregation in some way drives the progression and spread of tauopathy. We believe that new studies are now warranted to understand the relationship between synaptic and network activity, the sleep/wake cycle, and the impact of the apoE/HSPG/LRP1 on A?, tau, and the spreading of these protein aggregates in the brain. The overall hypothesis of this PPG renewal is that the sleep-wake cycle and brain network activity modulates both A? and tau aggregation and the effect of A? on tau spreading. We further hypothesize that apoE/LRP1/HSPG pathways influence these effects. We will utilize innovative techniques and approaches to study these hypotheses such as the use of DREADDs, in vivo microdialysis, and microimmunoelectrodes as well as a variety of genetically modified mouse models and viral vectors. The specific projects and Cores are listed here. Project 1, D. Holtzman, PI: Effects of the sleep/wake cycle on A?, tau, and spreading. Project 2, J. Cirrito, PI: Neuronal Network Regulation in A? and Tau Conformation and Spreading. Project 3, G. Bu, PI: Neuronal LRP1 and HSPG in pathological spreading of A? and tau. Core A: Administration (D. Holtzman, PI); Core B: Viral Vectors Core (B. J. Snider, PI).

Public Health Relevance

The aggregation and spreading of amyloid-? (A?) and tau via synaptic connections within brain networks appears to play a critical role in Alzheimer?s disease. We are exploring how factors such as the sleep wake cycle, brain network activity, and specific neuronal receptors for A? and tau influence A? and tau accumulation as well as A? induced tau spreading. These studies should provide novel insights into how sleep, brain network activity, and specific cell surface receptors influence Alzheimer?s disease risk and may suggest new avenues for treatment.

National Institute of Health (NIH)
National Institute of Neurological Disorders and Stroke (NINDS)
Research Program Projects (P01)
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Special Emphasis Panel (ZNS1)
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Mcgavern, Linda
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Washington University
Schools of Medicine
Saint Louis
United States
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Zhao, Na; Liu, Chia-Chen; Qiao, Wenhui et al. (2018) Apolipoprotein E, Receptors, and Modulation of Alzheimer's Disease. Biol Psychiatry 83:347-357
Musiek, Erik S; Bhimasani, Meghana; Zangrilli, Margaret A et al. (2018) Circadian Rest-Activity Pattern Changes in Aging and Preclinical Alzheimer Disease. JAMA Neurol 75:582-590
Kress, Geraldine J; Liao, Fan; Dimitry, Julie et al. (2018) Regulation of amyloid-? dynamics and pathology by the circadian clock. J Exp Med 215:1059-1068
Ogaki, Kotaro; Martens, Yuka A; Heckman, Michael G et al. (2018) Multiple system atrophy and apolipoprotein E. Mov Disord 33:647-650
Liao, Fan; Li, Aimin; Xiong, Monica et al. (2018) Targeting of nonlipidated, aggregated apoE with antibodies inhibits amyloid accumulation. J Clin Invest 128:2144-2155
Kang, S S; Ren, Y; Liu, C-C et al. (2018) Lipocalin-2 protects the brain during inflammatory conditions. Mol Psychiatry 23:344-350
Hettinger, Jane C; Lee, Hyo; Bu, Guojun et al. (2018) AMPA-ergic regulation of amyloid-? levels in an Alzheimer's disease mouse model. Mol Neurodegener 13:22
Yuede, Carla M; Timson, Benjamin F; Hettinger, Jane C et al. (2018) Interactions between stress and physical activity on Alzheimer's disease pathology. Neurobiol Stress 8:158-171
Shinohara, Mitsuru; Koga, Shunsuke; Konno, Takuya et al. (2017) Distinct spatiotemporal accumulation of N-truncated and full-length amyloid-?42 in Alzheimer's disease. Brain 140:3301-3316
Zhong, Li; Chen, Xiao-Fen; Wang, Tingting et al. (2017) Soluble TREM2 induces inflammatory responses and enhances microglial survival. J Exp Med 214:597-607

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