Exploring TDP-43 aggregation and disaggregation A spectrum of seemingly diverse neurodegenerative disorders is now unified by a common underlying theme: the accumulation of non-amyloid, ubiquitylated TDP-43 inclusions in the central nervous system. These lethal disorders range from amyotrophic lateral sclerosis (ALS) to frontal temporal dementia lobar degeneration with ubiquitin positive inclusions (FTLD-U). A causative role for TDP-43 in ALS pathogenesis has been validated by the isolation of mutations in the TDP-43 gene, which are associated with familial and sporadic forms of ALS. Moreover, a yeast model of TDP-43 proteinopathies has established a direct connection between TDP-43 aggregation and toxicity. However, the mechanistic basis of TDP-43 aggregation and how ALS-associated mutations affect the aggregation process directly remain unclear. Further, whether there are cellular factors that can antagonize or reverse the aggregation process remains unknown. We are particularly interested in how two AAA+ ATPases, Hsp104 and p97, might antagonize or reverse TDP-43 aggregation. Hsp104 solubilizes and reactivates proteins from denatured aggregates. p97 prevents aggregation of model substrates, and mutations in p97 are linked with conditions where TDP-43 forms intranuclear aggregates. We hypothesize that understanding these issues will greatly enhance our understanding of ALS and related disorders. Hence, we aim to: (1) Define the mechanisms of TDP-43 aggregation using pure components in vitro. (2) Antagonize and reverse TDP-43 aggregation with Hsp104 and p97 in vitro. (3) Prevent or reverse TDP- 43 aggregation and toxicity in vivo. These studies will provide important new mechanistic insights into TDP-43 aggregation and toxicity and how this might be antagonized. Realization of our objectives will empower the development of therapies for ALS and other TDP-43 proteinopathies.

Public Health Relevance

Several devastating diseases that are caused by nerve degeneration, including amyotrophic lateral sclerosis (ALS), have been unified by a common underlying theme: the clumping of a protein, TDP-43, in nerve cells. Our proposed studies aim to provide new mechanistic insights into how TDP-43 clumps and is toxic, and how this process might be antagonized or reversed. Realization of our objectives will empower the development of new therapies for ALS and related disorders, which are currently untreatable.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Exploratory/Developmental Grants (R21)
Project #
1R21NS067354-01
Application #
7773384
Study Section
Cellular and Molecular Biology of Neurodegeneration Study Section (CMND)
Program Officer
Sutherland, Margaret L
Project Start
2009-09-30
Project End
2011-08-31
Budget Start
2009-09-30
Budget End
2010-08-31
Support Year
1
Fiscal Year
2009
Total Cost
$198,959
Indirect Cost
Name
University of Pennsylvania
Department
Biochemistry
Type
Schools of Medicine
DUNS #
042250712
City
Philadelphia
State
PA
Country
United States
Zip Code
19104
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Jackrel, Meredith E; Shorter, James (2015) Engineering enhanced protein disaggregases for neurodegenerative disease. Prion 9:90-109
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Jackrel, Meredith E; Shorter, James (2014) Reversing deleterious protein aggregation with re-engineered protein disaggregases. Cell Cycle 13:1379-83
Seither, Katelyn M; McMahon, Heather A; Singh, Nikita et al. (2014) Specific aromatic foldamers potently inhibit spontaneous and seeded A?42 and A?43 fibril assembly. Biochem J 464:85-98
Jackrel, Meredith E; Shorter, James (2014) Potentiated Hsp104 variants suppress toxicity of diverse neurodegenerative disease-linked proteins. Dis Model Mech 7:1175-84
Jackrel, Meredith E; Tariq, Amber; Yee, Keolamau et al. (2014) Isolating potentiated Hsp104 variants using yeast proteinopathy models. J Vis Exp :e52089
Li, Yun R; King, Oliver D; Shorter, James et al. (2013) Stress granules as crucibles of ALS pathogenesis. J Cell Biol 201:361-72

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