Cellular Models of Aggregation-Dependent Template-Directed Proteolysis to Characterize Tau Aggregation Inhibitors for Treatment of Alzheimer's Disease

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Abstract

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 have been able to determine for the first time, is 0.12 μM. These values are close to the steady state trough brain concentration of methylthioninium ion (0.18 μM) that is required to arrest progression of AD on clinical and imaging endpoints, and the minimum brain concentration (0.13 μM) required to reverse behavioral deficits and pathology in tau transgenic mice.

Original languageEnglish
Pages (from-to)10862-10875
Number of pages14
JournalThe Journal of Biological Chemistry
Volume290
Issue number17
Early online date10 Mar 2015
DOIs
Publication statusPublished - 24 Apr 2015

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Proteolysis
Alzheimer Disease
Agglomeration
Brain
Salts
Tauopathies
tau Proteins
Prions
Methylene Blue
Transgenic Mice
Pharmacokinetics
Ions
Pathology
Toxicity
Dissolution
Tissue
Crystalline materials
Imaging techniques

Keywords

  • Alzheimer Disease
  • cell biology
  • protein aggregation
  • tau protein (tau)
  • tauopathy
  • LMTX
  • prion-like processing
  • methylthioninium

Cite this

@article{55cb2b04b24545acb4b6c9dfd2c706e3,
title = "Cellular Models of Aggregation-Dependent Template-Directed Proteolysis to Characterize Tau Aggregation Inhibitors for Treatment of Alzheimer's Disease",
abstract = "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{\circledR}) which overcome the pharmacokinetic limitations of methylthioninium chloride. LMTX{\circledR}, 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 have been able to determine for the first time, is 0.12 μM. These values are close to the steady state trough brain concentration of methylthioninium ion (0.18 μM) that is required to arrest progression of AD on clinical and imaging endpoints, and the minimum brain concentration (0.13 μM) required to reverse behavioral deficits and pathology in tau transgenic mice.",
keywords = "Alzheimer Disease, cell biology, protein aggregation, tau protein (tau), tauopathy, LMTX, prion-like processing, methylthioninium",
author = "Harrington, {Charles R} and Storey, {John M D} and Scott Clunas and Harrington, {Kathleen A} and David Horsley and Ahtsham Ishaq and Kemp, {Steven J} and Larch, {Christopher P} and Colin Marshall and Nicoll, {Sarah L} and Rickard, {Janet E} and Michael Simpson and Sinclair, {James P} and Storey, {Lynda J} and Wischik, {Claude M}",
note = "Copyright {\circledC} 2015, The American Society for Biochemistry and Molecular Biology. Acknowledgements-We thank Drs Timo Rager and Rolf Hilfiker (Solvias, Switzerland) for polymorph analyses.",
year = "2015",
month = "4",
day = "24",
doi = "10.1074/jbc.M114.616029",
language = "English",
volume = "290",
pages = "10862--10875",
journal = "The Journal of Biological Chemistry",
issn = "0021-9258",
publisher = "AMER SOC BIOCHEMISTRY MOLECULAR BIOLOGY INC",
number = "17",

}

TY - JOUR

T1 - Cellular Models of Aggregation-Dependent Template-Directed Proteolysis to Characterize Tau Aggregation Inhibitors for Treatment of Alzheimer's Disease

AU - Harrington, Charles R

AU - Storey, John M D

AU - Clunas, Scott

AU - Harrington, Kathleen A

AU - Horsley, David

AU - Ishaq, Ahtsham

AU - Kemp, Steven J

AU - Larch, Christopher P

AU - Marshall, Colin

AU - Nicoll, Sarah L

AU - Rickard, Janet E

AU - Simpson, Michael

AU - Sinclair, James P

AU - Storey, Lynda J

AU - Wischik, Claude M

N1 - Copyright © 2015, The American Society for Biochemistry and Molecular Biology. Acknowledgements-We thank Drs Timo Rager and Rolf Hilfiker (Solvias, Switzerland) for polymorph analyses.

PY - 2015/4/24

Y1 - 2015/4/24

N2 - 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 have been able to determine for the first time, is 0.12 μM. These values are close to the steady state trough brain concentration of methylthioninium ion (0.18 μM) that is required to arrest progression of AD on clinical and imaging endpoints, and the minimum brain concentration (0.13 μM) required to reverse behavioral deficits and pathology in tau transgenic mice.

AB - 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 have been able to determine for the first time, is 0.12 μM. These values are close to the steady state trough brain concentration of methylthioninium ion (0.18 μM) that is required to arrest progression of AD on clinical and imaging endpoints, and the minimum brain concentration (0.13 μM) required to reverse behavioral deficits and pathology in tau transgenic mice.

KW - Alzheimer Disease

KW - cell biology

KW - protein aggregation

KW - tau protein (tau)

KW - tauopathy

KW - LMTX

KW - prion-like processing

KW - methylthioninium

U2 - 10.1074/jbc.M114.616029

DO - 10.1074/jbc.M114.616029

M3 - Article

VL - 290

SP - 10862

EP - 10875

JO - The Journal of Biological Chemistry

JF - The Journal of Biological Chemistry

SN - 0021-9258

IS - 17

ER -