Alzheimer's disease (AD) affects 5.2 million Americans over 65, a number expected to increase along with the general aging of the US population. While remarkable progress has been made in the last decade in defining the toxic effects of the amyloid species thought to be involved in loss of cognitive function, much remains to be learned regarding amyloid plaque pathogenesis. Recent data support the idea that chaperones, proteins which control folding homeostasis, contribute to proper neuronal function in a variety of ways. Our laboratory has recently shown that 7B2, a small secreted neuronal protein, is associated with brain amyloid plaques in tissues from both AD humans and from mouse AD models. These data are supported by five independent bioinformatics studies indicating that this protein represents a potential CSF biomarker for neurodegenerative disease. Although present in the secretory pathway and not the cytosol, 7B2 exhibits many biochemical characteristics similar to those of small heat shock protein chaperones. Like alpha crystallin, a member of the heat shock chaperone family, 7B2 can potently block the fibrillation of beta amyloid 1-42 in in vitro tests, and also blocks the cytotoxicity of beta amyloid added to Neuro 2A cell cultures. The current R21 proposal is to test the hypothesis that brain 7B2 levels can control the extent of amyloid plaque deposition and affect cognition in a known mouse model of Alzheimer's. We propose to cross existing mouse strains that either over- or underexpress 7B2 with the APP/PS1 Alzheimer's disease model mouse. Cognitive abilities will be assessed at 6 and 12 months of age in a Morris water maze. Plaque pathology will be quantitated in cortical and hippocampal slices in 6 animals of each genotype; 7B2 immunoreactivity will be measured in concert. Amyloid oligomerization state will be examined in brains of separate animals using chemical and centrifugal separation followed by ELISA and also correlated with genotype. Collectively, these experiments constitute a direct test of our hypothesis that 7B2 levels are negatively correlated with amyloid plaque and oligomer formation.

Public Health Relevance

One in eight Americans is now thought to have Alzheimer's disease; because of the general aging of the American population, the annual incidence of this debilitating disease is projected to double within the next 30 years, growing to 11-16 million. Yet effective therapeutic avenues to address this devastating disease are not available, in part because so little is known about the mechanisms underlying beta amyloid plaque formation and dissolution. In this proposal we will examine whether changing brain levels of known neuronal chaperone protein, 7B2, will influence plaque density and will affect the known behavioral changes caused by Alzheimer's mutations in a mouse model of this disease.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Exploratory/Developmental Grants (R21)
Project #
5R21AG045741-02
Application #
8919199
Study Section
Cell Death in Neurodegeneration Study Section (CDIN)
Program Officer
Yang, Austin Jyan-Yu
Project Start
2014-09-01
Project End
2016-04-30
Budget Start
2015-05-01
Budget End
2016-04-30
Support Year
2
Fiscal Year
2015
Total Cost
$249,399
Indirect Cost
$86,924
Name
University of Maryland Baltimore
Department
Anatomy/Cell Biology
Type
Schools of Medicine
DUNS #
188435911
City
Baltimore
State
MD
Country
United States
Zip Code
21201
Jarvela, Timothy S; Womack, Tasha; Georgiou, Polymnia et al. (2018) 7B2 chaperone knockout in APP model mice results in reduced plaque burden. Sci Rep 8:9813
Jarvela, Timothy S; Lam, Hoa A; Helwig, Michael et al. (2016) The neural chaperone proSAAS blocks ?-synuclein fibrillation and neurotoxicity. Proc Natl Acad Sci U S A 113:E4708-15
Lindberg, Iris; Shorter, James; Wiseman, R Luke et al. (2015) Chaperones in Neurodegeneration. J Neurosci 35:13853-9