The pathological aggregation of the microtubule-associated protein tau and its subsequent accumulation into neurofibrillary tangles (NFTs) and other hyperphosphorylated tau-containing inclusions are defining histopathological features of Alzheimer?s disease (AD) and several other neurodegenerative disorders collectively known as tauopathies. These diseases affect millions of people in the United States and exact enormous personal and financial costs on those afflicted and their loved ones. However, while amyloid-? (A?) and tau aggregates in the brain are the common pathological hallmarks of AD, the disease is heterogeneous with different comorbid pathologies and symptom progression rates. Recent studies suggest that NFTs are not the most toxic tau entities in tauopathies; rather tau oligomers?soluble intermediates between monomers and NFTs?have emerged as an important drug target due to their toxicity, seeding potency, and ability to propagate a specific abnormal tau conformation and thus initiate widespread tau pathology. Our data suggest that oligomers composed of different proteins might give rise to increased and diverse tau oligomerization, resulting in different pathologies and phenotypes that sometimes overlap with other neurodegenerative diseases. The dynamic and hydrophobic nature of tau oligomers allows for the formation of heterogeneous populations of aggregates that include distinct tau oligomeric conformers (strains). In this proposal we will test the tau oligomeric strain hypothesis in AD by defining strain characteristics and potential mechanisms of strain formation and propagation.
Specific aim 1 will test the hypothesis that diverse tau oligomeric strains are found in AD brain and CSF.
Specific aim 2 will test the hypothesis that brain-derived tau oligomeric strains arise from cross-seeding other amyloidogenic proteins and propagate pathology in vivo. This research proposal will yield useful results with great potential to advance the development of diagnostic and therapeutic applications to target toxic tau oligomers in AD. The elucidation of different tau oligomeric strains and their roles in disease progression may reveal novel therapeutic strategies and identify upstream drug targets for treating AD. Moreover, a better understanding of tau strains could help identify useful approaches for screening the best drug candidates. Finally, it could provide novel insights into the design of future clinical trials and introduce the exciting possibility of personalized medicine to treat AD and other tauopathies.

Public Health Relevance

Millions people in the United States are affected by Alzheimer`s diseases (AD) and the incidence of these diseases is on the rise and yet there is a paucity of effective therapies. We and others recently demonstrated e. tau oligomers, may constitute a distinct toxic species in AD and other tauopathies. The pathological protein aggregates in AD are heterogeneous which makes it hard for diagnosis and treatment. The elucidation of different tau oligomeric strains and their roles in AD will advance diagnostic applications and may also reveal new targets for novel therapeutic strategies which would improve the health and well-being of the growing aging population in the US.

Agency
National Institute of Health (NIH)
Institute
National Institute on Aging (NIA)
Type
Research Project (R01)
Project #
1R01AG054025-01
Application #
9194258
Study Section
Special Emphasis Panel (ZRG1-MDCN-T (56)R)
Program Officer
Yang, Austin Jyan-Yu
Project Start
2016-07-15
Project End
2021-03-31
Budget Start
2016-07-15
Budget End
2017-03-31
Support Year
1
Fiscal Year
2016
Total Cost
$387,500
Indirect Cost
$137,500
Name
University of Texas Medical Br Galveston
Department
Neurology
Type
Schools of Medicine
DUNS #
800771149
City
Galveston
State
TX
Country
United States
Zip Code
77555
Ghag, Gaurav; Bhatt, Nemil; Cantu, Daniel V et al. (2018) Soluble tau aggregates, not large fibrils, are the toxic species that display seeding and cross-seeding behavior. Protein Sci 27:1901-1909
Sengupta, Urmi; Montalbano, Mauro; McAllen, Salome et al. (2018) Formation of Toxic Oligomeric Assemblies of RNA-binding Protein: Musashi in Alzheimer's disease. Acta Neuropathol Commun 6:113
Ha, Yonju; Liu, Wei; Liu, Hua et al. (2018) AAV2-mediated GRP78 Transfer Alleviates Retinal Neuronal Injury by Downregulating ER Stress and Tau Oligomer Formation. Invest Ophthalmol Vis Sci 59:4670-4682
Gerson, Julia E; Farmer, Kathleen M; Henson, Natalie et al. (2018) Tau oligomers mediate ?-synuclein toxicity and can be targeted by immunotherapy. Mol Neurodegener 13:13
Bittar, Alice; Sengupta, Urmi; Kayed, Rakez (2018) Prospects for strain-specific immunotherapy in Alzheimer's disease and tauopathies. NPJ Vaccines 3:9
Wang, Peng; Lo Cascio, Filippa; Gao, Jia et al. (2018) Binding and neurotoxicity mitigation of toxic tau oligomers by synthetic heparin like oligosaccharides. Chem Commun (Camb) 54:10120-10123
Castillo-Carranza, Diana L; Guerrero-Muñoz, Marcos J; Sengupta, Urmi et al. (2018) ?-Synuclein Oligomers Induce a Unique Toxic Tau Strain. Biol Psychiatry 84:499-508
Sengupta, Urmi; Portelius, Erik; Hansson, Oskar et al. (2017) Tau oligomers in cerebrospinal fluid in Alzheimer's disease. Ann Clin Transl Neurol 4:226-235
Nilson, Ashley N; English, Kelsey C; Gerson, Julia E et al. (2017) Tau Oligomers Associate with Inflammation in the Brain and Retina of Tauopathy Mice and in Neurodegenerative Diseases. J Alzheimers Dis 55:1083-1099
Ha, Yonju; Liu, Hua; Zhu, Shuang et al. (2017) Critical Role of the CXCL10/C-X-C Chemokine Receptor 3 Axis in Promoting Leukocyte Recruitment and Neuronal Injury during Traumatic Optic Neuropathy Induced by Optic Nerve Crush. Am J Pathol 187:352-365

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