Peptide-based inhibitors of Tau aggregation as a potential therapeutic for Alzheimer’s disease and other Tauopathies (original) (raw)
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2021
The spread of neurofibrillary tangles resulting from tau protein aggregation is a hallmark of Alzheimer’s and related neurodegenerative diseases. Early oligomerization of tau involves conformational reorganization into parallel b-sheet structures and supramolecular assembly into toxic fibrils. Despite the need for selective inhibitors of tau propagation, b-rich protein assemblies are inherently difficult to target with small molecules. Here, we describe a minimalist approach to mimic the aggregation-prone modules within tau. We carried out a backbone residue scan and show that amide N-amination completely abolishes the tendency of these peptides to self-aggregate, rendering them soluble mimics of ordered b-strands from the tau R2 and R3 domains. Several N-amino peptides (NAPs) inhibit disease-associated tau aggregation and prevent fibril formation in vitro. We further demonstrate that NAPs 12 and 13 are effective at blocking the cellular seeding of endogenous tau by interacting with...
Chemistry: A European Journal, 2017
Inhibiting the toxic aggregation of amyloid-β and the tau protein, the key pathological agents involved in Alzheimer's, is a leading approach in modulating disease progression. Using an aggregative tau-derived model peptide, Ac-PHF6-NH2, we show that substitution of its amino acids with Proline, a known efficient β-breaker, reduces its self-assembly. This effect is attributed to the steric hindrance created by the Proline substitution, which results in disruption of the β-sheet formation process. Moreover, several of the Proline-substituted peptides inhibit the aggregation of Ac-PHF6-NH2 amyloidogenic peptide. Two of these modified inhibitors also disassemble pre-formed Ac-PHF6-NH2 fibrils and one inhibits its induced cytotoxicity. Taken together, our data suggest that these lead β-breaker peptides may be developed into novel Alzheimer's disease therapeutics.
The Journal of biological chemistry, 2015
Alzheimer's disease (AD) is a degenerative tauopathy characterized by aggregation of tau protein through the repeat domain to form intraneuronal paired helical filaments (PHFs). We report two cell models in which we control the inherent toxicity of the core-tau fragment. These models demonstrate the properties of prion-like recruitment of full-length tau into an aggregation pathway in which template-directed, endogenous truncation propagates aggregation through the core-tau binding domain. We use these in combination with dissolution of native PHFs to quantify the activity of tau aggregation inhibitors (TAIs). We report the synthesis of novel stable crystalline leucomethylthioninium salts (LMTX®) which overcome the pharmacokinetic limitations of methylthioninium chloride. LMTX®, as either a dihydromesylate or a dihydrobromide salt, retains TAI activity in vitro, and disrupts PHFs isolated from AD brain tissues at 0.16 μM. The Ki value for intracellular TAI activity, which we hav...
2021
Tau proteins aggregate into filaments in brain cells in Alzheimer’s disease and related disorders referred to as tauopathies. Here, we used fragments of camelid heavy-chain-only antibodies (VHHs or single domain antibody fragments) targeting Tau as immuno-modulators of its pathologic seeding. A VHH issued from the screen against Tau of a synthetic phage-display library of humanized VHHs was selected for its capacity to bind Tau microtubule-binding domain, composing the core of Tau fibrils. This lead VHH was optimized to improve its biochemical properties and to act in the intracellular compartment, resulting in VHH Z70. VHH Z70 was more efficient than the lead to inhibit in vitro Tau aggregation in heparin-induced assays. Expression of VHH Z70 in a cellular model of Tau seeding also decreased the fluorescence-reported aggregation. Finally, intracellular expression of VHH Z70 in the brain of an established tauopathy mouse seeding model demonstrated its capacity to mitigate accumulati...
In Vitro Aggregation Assays Using Hyperphosphorylated Tau Protein
Journal of Visualized Experiments, 2015
Alzheimer's disease is one of a large group of neurodegenerative disorders known as tauopathies that are manifested by the neuronal deposits of hyperphosphorylated tau protein in the form of neurofibrillary tangles (NFTs). The density of NFT correlates well with cognitive impairment and other neurodegenerative symptoms, thus prompting the endeavor of developing tau aggregation-based therapeutics. Thus far, however, tau aggregation assays use recombinant or synthetic tau that is devoid of the pathology-related phosphorylation marks. Here we describe two assays using recombinant, hyperphosphorylated tau as the subject. These assays can be scaled up for high-throughput screens for compounds that can modulate the kinetics or stability of hyperphosphorylated tau aggregates. Novel therapeutics for Alzheimer's disease and other tauopathies can potentially be discovered using hyperphosphorylated tau isoforms.
Tau-Based Therapeutic Approaches for Alzheimer's Disease - A Mini-Review
Gerontology, 2014
The accumulation of aggregated, hyperphosphorylated tau as neurofibrillary tangles and neuropil threads are cardinal features of Alzheimer's disease (AD). The other lesions found in AD include amyloid plaques and congophilic amyloid angiopathy, both associated with the extracellular accumulation of the amyloid-beta (Aβ) peptide. AD is the most common cause of dementia globally. Currently, there are no effective means to treat AD or even to slow it down. The dominant theory for the causation of AD is the amyloid cascade hypothesis, which suggests that the aggregation of Aβ as oligomers and amyloid plaques is central to the pathogenesis of AD. Numerous therapies have been developed directed to Aβ-related pathology, in particular various immunotherapeutic approaches. So far all of these have failed in clinical trials. Recently, there has been more focus on therapy directed to tau-related pathology, which correlates better with the cognitive status of patients, compared to the amylo...
Structure based inhibitors of Amyloid Beta core suggest a common interface with Tau
eLife
Alzheimer's disease (AD) pathology is characterized by plaques of amyloid beta (Aβ) and neurofibrillary tangles of tau. Aβ aggregation is thought to occur at early stages of the disease, and ultimately gives way to the formation of tau tangles which track with cognitive decline in humans. Here, we report the crystal structure of an Aβ core segment determined by MicroED and in it, note characteristics of both fibrillar and oligomeric structure. Using this structure, we designed peptide-based inhibitors that reduce Aβ aggregation and toxicity of already-aggregated species. Unexpectedly, we also found that these inhibitors reduce the efficiency of Aβ-mediated tau aggregation, and moreover reduce aggregation and self-seeding of tau fibrils. The ability of these inhibitors to interfere with both Aβ and tau seeds suggests these fibrils share a common epitope, and supports the hypothesis that cross-seeding is one mechanism by which amyloid is linked to tau aggregation and could promote...