Cysteine-independent inhibition of Alzheimer's disease-like paired helical filament assembly by leuco-methylthioninium (LMT)

Youssra K. Al-Hilaly; Saskia J. Pollack; Janet E. Rickard; Michael Simpson; Ana-C Raulin; Thomas Baddeley; Pascale Schellenberger; John M. D. Storey; Charles R. Harrington; Claude M. Wischik; Louise C. Serpell

doi:10.1016/j.jmb.2018.08.010

Cysteine-independent inhibition of Alzheimer's disease-like paired helical filament assembly by leuco-methylthioninium (LMT)

Youssra K. Al-Hilaly, Saskia J. Pollack, Janet E. Rickard, Michael Simpson, Ana-C Raulin, Thomas Baddeley, Pascale Schellenberger, John M. D. Storey, Charles R. Harrington, Claude M. Wischik^* (Corresponding Author), Louise C. Serpell^* (Corresponding Author)

^*Corresponding author for this work

Research output: Contribution to journal › Article › peer-review

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Abstract

Alzheimer's disease (AD) is a tauopathy characterised by pathological fibrillisation of tau protein to form the paired helical filaments (PHFs) which constitute neurofibrillary tangles. The methylthioninium (MT) moiety reverses the proteolytic stability of the PHF core and is in clinical development for treatment of AD in a stable reduced form as leuco-MT (LMT). It has been hypothesised that MT acts via oxidation of cysteine residues which is incompatible with activity in the predominantly reducing environment of living cells. We have shown recently that the PHF-core tau unit assembles spontaneously in vitro to form PHF-like filaments. Here we describe studies using circular dichroism, SDS-polyacrylamide gel electrophoresis, transmission electron microscopy and site-directed mutagenesis to elucidate the mechanism of action of the MT moiety. We show that MT inhibitory activity is optimal in reducing conditions, that the active moiety is the reduced LMT form of the molecule, and that its mechanism of action is cysteine-independent.

Original language	English
Pages (from-to)	4119-4131
Number of pages	13
Journal	Journal of Molecular Biology
Volume	430
Issue number	21
Early online date	16 Aug 2018
DOIs	https://doi.org/10.1016/j.jmb.2018.08.010
Publication status	Published - 19 Oct 2018

Bibliographical note

TEM work was performed at the School of Life Sciences TEM Imaging Centre at the University of Sussex, which is supported by the Wellcome Trust and RM Phillips.

SP and AR are supported by a Sussex Neuroscience doctoral training centre. LCS is supported by Alzheimer's Society and Alzheimer's Research UK Southcoast Network.

YA, JR, TB and MS are supported by TauRx Therapeutics Ltd. and CH, JS and CW serve as officers in TauRx Therapeutics Ltd.

Keywords

Tau
Methylthioninium
Hydromethylthionine
Neurofibrillary tangles
Circular dichroism
Electron microscopy

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Cysteine-Independent Inhibition of Alzheimer's Disease-like Paired Helical Filament Assembly by Leuco-Methylthioninium
Under a Creative Commons license https://creativecommons.org/licenses/by/4.0/
Final published version, 2.29 MBLicence: CC BY

Charles Harrington
Person: Academic Related - Research

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Al-Hilaly, Y. K., Pollack, S. J., Rickard, J. E., Simpson, M., Raulin, A.-C., Baddeley, T., Schellenberger, P., Storey, J. M. D., Harrington, C. R., Wischik, C. M., & Serpell, L. C. (2018). Cysteine-independent inhibition of Alzheimer's disease-like paired helical filament assembly by leuco-methylthioninium (LMT). Journal of Molecular Biology, 430(21), 4119-4131. https://doi.org/10.1016/j.jmb.2018.08.010

Al-Hilaly, YK, Pollack, SJ, Rickard, JE, Simpson, M, Raulin, A-C, Baddeley, T, Schellenberger, P, Storey, JMD , Harrington, CR , Wischik, CM & Serpell, LC 2018, 'Cysteine-independent inhibition of Alzheimer's disease-like paired helical filament assembly by leuco-methylthioninium (LMT)', Journal of Molecular Biology, vol. 430, no. 21, pp. 4119-4131. https://doi.org/10.1016/j.jmb.2018.08.010

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title = "Cysteine-independent inhibition of Alzheimer's disease-like paired helical filament assembly by leuco-methylthioninium (LMT)",

abstract = "Alzheimer's disease (AD) is a tauopathy characterised by pathological fibrillisation of tau protein to form the paired helical filaments (PHFs) which constitute neurofibrillary tangles. The methylthioninium (MT) moiety reverses the proteolytic stability of the PHF core and is in clinical development for treatment of AD in a stable reduced form as leuco-MT (LMT). It has been hypothesised that MT acts via oxidation of cysteine residues which is incompatible with activity in the predominantly reducing environment of living cells. We have shown recently that the PHF-core tau unit assembles spontaneously in vitro to form PHF-like filaments. Here we describe studies using circular dichroism, SDS-polyacrylamide gel electrophoresis, transmission electron microscopy and site-directed mutagenesis to elucidate the mechanism of action of the MT moiety. We show that MT inhibitory activity is optimal in reducing conditions, that the active moiety is the reduced LMT form of the molecule, and that its mechanism of action is cysteine-independent.",

keywords = "Tau, Methylthioninium, Hydromethylthionine, Neurofibrillary tangles, Circular dichroism, Electron microscopy",

author = "Al-Hilaly, {Youssra K.} and Pollack, {Saskia J.} and Rickard, {Janet E.} and Michael Simpson and Ana-C Raulin and Thomas Baddeley and Pascale Schellenberger and Storey, {John M. D.} and Harrington, {Charles R.} and Wischik, {Claude M.} and Serpell, {Louise C.}",

note = "TEM work was performed at the School of Life Sciences TEM Imaging Centre at the University of Sussex, which is supported by the Wellcome Trust and RM Phillips. SP and AR are supported by a Sussex Neuroscience doctoral training centre. LCS is supported by Alzheimer's Society and Alzheimer's Research UK Southcoast Network. YA, JR, TB and MS are supported by TauRx Therapeutics Ltd. and CH, JS and CW serve as officers in TauRx Therapeutics Ltd.",

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doi = "10.1016/j.jmb.2018.08.010",

language = "English",

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AU - Al-Hilaly, Youssra K.

AU - Pollack, Saskia J.

AU - Rickard, Janet E.

AU - Simpson, Michael

AU - Raulin, Ana-C

AU - Baddeley, Thomas

AU - Schellenberger, Pascale

AU - Storey, John M. D.

AU - Harrington, Charles R.

AU - Wischik, Claude M.

AU - Serpell, Louise C.

N1 - TEM work was performed at the School of Life Sciences TEM Imaging Centre at the University of Sussex, which is supported by the Wellcome Trust and RM Phillips. SP and AR are supported by a Sussex Neuroscience doctoral training centre. LCS is supported by Alzheimer's Society and Alzheimer's Research UK Southcoast Network. YA, JR, TB and MS are supported by TauRx Therapeutics Ltd. and CH, JS and CW serve as officers in TauRx Therapeutics Ltd.

PY - 2018/10/19

Y1 - 2018/10/19

N2 - Alzheimer's disease (AD) is a tauopathy characterised by pathological fibrillisation of tau protein to form the paired helical filaments (PHFs) which constitute neurofibrillary tangles. The methylthioninium (MT) moiety reverses the proteolytic stability of the PHF core and is in clinical development for treatment of AD in a stable reduced form as leuco-MT (LMT). It has been hypothesised that MT acts via oxidation of cysteine residues which is incompatible with activity in the predominantly reducing environment of living cells. We have shown recently that the PHF-core tau unit assembles spontaneously in vitro to form PHF-like filaments. Here we describe studies using circular dichroism, SDS-polyacrylamide gel electrophoresis, transmission electron microscopy and site-directed mutagenesis to elucidate the mechanism of action of the MT moiety. We show that MT inhibitory activity is optimal in reducing conditions, that the active moiety is the reduced LMT form of the molecule, and that its mechanism of action is cysteine-independent.

AB - Alzheimer's disease (AD) is a tauopathy characterised by pathological fibrillisation of tau protein to form the paired helical filaments (PHFs) which constitute neurofibrillary tangles. The methylthioninium (MT) moiety reverses the proteolytic stability of the PHF core and is in clinical development for treatment of AD in a stable reduced form as leuco-MT (LMT). It has been hypothesised that MT acts via oxidation of cysteine residues which is incompatible with activity in the predominantly reducing environment of living cells. We have shown recently that the PHF-core tau unit assembles spontaneously in vitro to form PHF-like filaments. Here we describe studies using circular dichroism, SDS-polyacrylamide gel electrophoresis, transmission electron microscopy and site-directed mutagenesis to elucidate the mechanism of action of the MT moiety. We show that MT inhibitory activity is optimal in reducing conditions, that the active moiety is the reduced LMT form of the molecule, and that its mechanism of action is cysteine-independent.

KW - Tau

KW - Methylthioninium

KW - Hydromethylthionine

KW - Neurofibrillary tangles

KW - Circular dichroism

KW - Electron microscopy

U2 - 10.1016/j.jmb.2018.08.010

DO - 10.1016/j.jmb.2018.08.010

M3 - Article

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SN - 0022-2836

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EP - 4131

JO - Journal of Molecular Biology

JF - Journal of Molecular Biology

IS - 21

ER -

Cysteine-independent inhibition of Alzheimer's disease-like paired helical filament assembly by leuco-methylthioninium (LMT)

Abstract

Bibliographical note

Keywords

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Charles Harrington

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