Project 3 of the Johns Hopkins Alzheimer's Disease Research Center (ADRC) is titled """"""""Neuronal activity-dependent secretion of AB and immediate early genes"""""""". This project focuses on the activity-regulated gene termed Arc/Arg3.1, in order to identify mechanisms that are critical for secretion of the amyloid-beta peptide (AB) from neurons. Arc is an immediate early gene that is transcriptionally induced in response to forms of neuronal activity that underlie learning and memory. The overarching goal of the study is to examine the molecular mechanisms that underlie activity-dependent secretion of AB and to examine their potential impact on synaptic dysfunction in Alzheimer's disease (AD). There are four specific aims: (1) Aim 1: To examine the cellular basis of Arc-dependent AB secretion. We will test the hypothesis that Arc enhances the processing of amyloid precursor protein (APP) by gamma secretase in recycling endosomes. We will examine the model that Arc enhances AB generation by recruiting gamma secretase, either from the plasma membrane or intracellular endosomes, to endosomes that traffic APP from the plasma membrane. (2) Aim 2: To examine the hypothesis that Arc binding to presenilin 1 (PS-1) is essential for Arc-dependent AB generation. We will define regions of Arc and PS-1 that are necessary and sufficient for binding. As part of this analysis, we will identify peptides that can selectively block their interaction and we will test if these peptides can interrupt activity-dependent generation of AB in primary neuronal cultures. (3) Aim 3: To examine the hypothesis that Arc contributes to AB generation and plaque deposition in vivo. These studies will monitor the age and gender dependence of soluble and insoluble AB40/42 and plaque deposition in transgenic APPswe/PS1AE9/Arc+/+ mice versus APPswe/PS1AE9/Arc-/- mice. (4) Aim 4: To examine expression of Arc and associated proteins in the brains of cognitively normal and cognitively impaired subjects. Tissue samples will be obtained through the Neuropathology Core (Core D) of the ADRC. Preliminary studies indicate that Arc protein is up-regulated in brains of patients of AD. We will determine if this is consistent across a larger group of subjects and assess the association with plaques and with dementia severity.

Public Health Relevance

Understanding the mechanisms that influence the connections between brain cells and the accumulation of Alzheimer's pathology (amyloid plaques and neurofibrillary tangles) in the brains of some elderly subjects is of crucial importance in developing strategies to combat Alzheimer's disease, a neurodegenerative disorder which affects over 6 million Americans.

National Institute of Health (NIH)
National Institute on Aging (NIA)
Specialized Center (P50)
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Johns Hopkins University
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Kamil, Rebecca J; Jacob, Athira; Ratnanather, John Tilak et al. (2018) Vestibular Function and Hippocampal Volume in the Baltimore Longitudinal Study of Aging (BLSA). Otol Neurotol 39:765-771
Tian, Qu; Bair, Woei-Nan; Resnick, Susan M et al. (2018) ?-amyloid deposition is associated with gait variability in usual aging. Gait Posture 61:346-352
Brenowitz, Willa D; Han, Fang; Kukull, Walter A et al. (2018) Treated hypothyroidism is associated with cerebrovascular disease but not Alzheimer's disease pathology in older adults. Neurobiol Aging 62:64-71
Spira, Adam P (2018) Sleep and Health in Older Adulthood: Recent Advances and the Path Forward. J Gerontol A Biol Sci Med Sci 73:357-359
Mejia, Amanda F; Nebel, Mary Beth; Barber, Anita D et al. (2018) Improved estimation of subject-level functional connectivity using full and partial correlation with empirical Bayes shrinkage. Neuroimage 172:478-491
Hinkle, Jared T; Perepezko, Kate; Bakker, Catherine C et al. (2018) Domain-specific cognitive impairment in non-demented Parkinson's disease psychosis. Int J Geriatr Psychiatry 33:e131-e139
Burke, Shanna L; Hu, Tianyan; Fava, Nicole M et al. (2018) Sex differences in the development of mild cognitive impairment and probable Alzheimer's disease as predicted by hippocampal volume or white matter hyperintensities. J Women Aging :1-25
Chiang, Angie C A; Fowler, Stephanie W; Reddy, Rohit et al. (2018) Discrete Pools of Oligomeric Amyloid-? Track with Spatial Learning Deficits in a Mouse Model of Alzheimer Amyloidosis. Am J Pathol 188:739-756
Amjad, Halima; Wong, Stephanie K; Roth, David L et al. (2018) Health Services Utilization in Older Adults with Dementia Receiving Care Coordination: The MIND at Home Trial. Health Serv Res 53:556-579
Bai, Jiawei; Sun, Yifei; Schrack, Jennifer A et al. (2018) A two-stage model for wearable device data. Biometrics 74:744-752

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