For many neurodegenerative diseases, both effective treatments and underlying causes are unknown. A specific protein, TDP-43, has recently been shown to be abnormally deposited in multiple neurodegenerative diseases, including Amyotropic Lateral Sclerosis (ALS) and Frontotemporal Lobar Dementia (FTLD). TDP-43 (TARDBP) is a conserved, broadly expressed nuclear protein with demonstrated roles in mRNA splicing and stability. By analogy with other neurodegenerative diseases associated with specific protein inclusions or aggregates (e.g., huntingtin in Huntington's, 1-synuclein in Parkinson's, 1-amyloid peptide in Alzheimer's, etc.), there are good reasons to believe that TDP-43 plays a causal role in neurodegenerative pathology. We have expressed human TDP-43 in C. elegans in order to assess the effects of TDP-43 overexpression in an in vivo model. Our experiments show that transgenic worms with neuronal expression of human TDP-43 have an uncoordinated movement phenotype that is indicative of neuronal dysfunction. Thus, our data support a neurotoxic role for TDP-43. The molecular mechanism(s) by which TDP-43 may be neurotoxic are unclear, in part because the full range of TDP-43 function is unknown. TDP-43-positive inclusions occur in FTLD cases caused by loss-of-function mutations in progranulin but the biological connection between TDP-43 and progranulin has not been established. In this project, we will seek to identify the conserved functions of TDP-43 (and progranulin), and the molecular and cellular mechanisms by which TDP-43 causes neurodegeneration. Specifically, we will carefully characterize C. elegans strains with deletions of TDP-43 and progranulin to determine the functions of these genes at the organismal level. We will also generate and characterize a series of transgenic C. elegans strains expressing variants of human TDP-43 designed to elucidate the molecular mechanisms of TDP-43 toxicity. These transgenic strains will also be used in forward genetic screens to identify components of the TDP-43 neurotoxic pathway. The C. elegans studies will be complemented by parallel cell culture studies, which will serve to validate and extend findings made in the C. elegans model system.

Public Health Relevance

For many neurodegenerative diseases, both effective treatments and underlying causes are unknown. A specific protein, TDP-43, has recently been shown to be abnormally deposited in multiple neurodegenerative diseases, including Amyotropic Lateral Sclerosis (ALS) and Frontotemporal Lobar Dementia (FTLD). In this project we will use model systems to determine the functions of TDP-43 and how its deposition may cause neurodegeneration.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
5R01NS063964-04
Application #
8246448
Study Section
Cellular and Molecular Biology of Neurodegeneration Study Section (CMND)
Program Officer
Sutherland, Margaret L
Project Start
2009-04-01
Project End
2014-03-31
Budget Start
2012-04-01
Budget End
2013-03-31
Support Year
4
Fiscal Year
2012
Total Cost
$325,742
Indirect Cost
$77,282
Name
University of Colorado at Boulder
Department
Genetics
Type
Other Domestic Higher Education
DUNS #
007431505
City
Boulder
State
CO
Country
United States
Zip Code
80309
Tian, Feng; Yang, Wenlong; Mordes, Daniel A et al. (2016) Monitoring peripheral nerve degeneration in ALS by label-free stimulated Raman scattering imaging. Nat Commun 7:13283
Vatsavayai, Sarat C; Yoon, Soo Jin; Gardner, Raquel C et al. (2016) Timing and significance of pathological features in C9orf72 expansion-associated frontotemporal dementia. Brain 139:3202-3216
Kramer, Nicholas J; Carlomagno, Yari; Zhang, Yong-Jie et al. (2016) Spt4 selectively regulates the expression of C9orf72 sense and antisense mutant transcripts. Science 353:708-12
Zhang, Yong-Jie; Gendron, Tania F; Grima, Jonathan C et al. (2016) C9ORF72 poly(GA) aggregates sequester and impair HR23 and nucleocytoplasmic transport proteins. Nat Neurosci 19:668-77
Jiang, Jie; Zhu, Qiang; Gendron, Tania F et al. (2016) Gain of Toxicity from ALS/FTD-Linked Repeat Expansions in C9ORF72 Is Alleviated by Antisense Oligonucleotides Targeting GGGGCC-Containing RNAs. Neuron 90:535-50
Peters, Owen M; Cabrera, Gabriela Toro; Tran, Helene et al. (2015) Human C9ORF72 Hexanucleotide Expansion Reproduces RNA Foci and Dipeptide Repeat Proteins but Not Neurodegeneration in BAC Transgenic Mice. Neuron 88:902-9
Chew, Jeannie; Gendron, Tania F; Prudencio, Mercedes et al. (2015) Neurodegeneration. C9ORF72 repeat expansions in mice cause TDP-43 pathology, neuronal loss, and behavioral deficits. Science 348:1151-4
Tran, Helene; Almeida, Sandra; Moore, Jill et al. (2015) Differential Toxicity of Nuclear RNA Foci versus Dipeptide Repeat Proteins in a Drosophila Model of C9ORF72 FTD/ALS. Neuron 87:1207-14
Gendron, Tania F; van Blitterswijk, Marka; Bieniek, Kevin F et al. (2015) Cerebellar c9RAN proteins associate with clinical and neuropathological characteristics of C9ORF72 repeat expansion carriers. Acta Neuropathol 130:559-73
Prudencio, Mercedes; Belzil, Veronique V; Batra, Ranjan et al. (2015) Distinct brain transcriptome profiles in C9orf72-associated and sporadic ALS. Nat Neurosci 18:1175-82

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