Pyrimethamine as a potential pharmacological chaperone for late-onset forms of GM2 gangliosidosis

Gustavo H B Maegawa, Michael Tropak, Justin Buttner, Tracy Stockley, Fernando Kok, Joe T R Clarke, Don J. Mahuran

Research output: Contribution to journalArticle

Abstract

Late-onset GM2 gangliosidosis is composed of two related, autosomal recessive, neurodegenerative diseases, both resulting from deficiency of lysosomal, heterodimeric β-hexosaminidase A(Hex A, αβ). Pharmacological chaperones (PC) are small molecules that can stabilize the conformation of a mutant protein, allowing it to pass the quality control system of the endoplasmic reticulum. To date all successful PCs have also been competitive inhibitors. Screening for Hex A inhibitors in a library of 1040 Food Drug Administration-approved compounds identified pyrimethamine (PYR (2,4-diamino 5-(4-chlorophenyl)-6-ethylpyrimidine)) as the most potent inhibitor. Cell lines from 10 late-onset Tay-Sachs (11 α-mutations, 2 novel) and 7 Sandhoff (9 β-mutations, 4 novel) disease patients, were cultured with PYR at concentrations corresponding to therapeutic doses. Cells carrying the most common late-onset mutation, αG269S, showed significant increases in residual Hex A activity, as did all 7 of the β-mutants tested. Cells responding to PC treatment included those carrying mutants resulting in reduced Hex heat stability and partial splice junction mutations of the inherently less stable α-subunit. PYR, which binds to the active site in domain II, was able to function as PC even to domain I β-mutants. We concluded that PYR functions as a mutation-specific PC, variably enhancing residual lysosomal Hex A levels in lateonset GM2 gangliosidosis patient cells.

Original languageEnglish (US)
Pages (from-to)9150-9161
Number of pages12
JournalJournal of Biological Chemistry
Volume282
Issue number12
DOIs
StatePublished - Mar 23 2007
Externally publishedYes

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GM2 Gangliosidosis
Hexosaminidase A
Pyrimethamine
Pharmacology
Mutation
Neurodegenerative diseases
Mutant Proteins
United States Food and Drug Administration
Endoplasmic Reticulum
Neurodegenerative Diseases
Quality Control
Libraries
Quality control
Conformations
Catalytic Domain
Screening
Hot Temperature
Cells
Control systems
Cell Line

ASJC Scopus subject areas

  • Biochemistry

Cite this

Maegawa, G. H. B., Tropak, M., Buttner, J., Stockley, T., Kok, F., Clarke, J. T. R., & Mahuran, D. J. (2007). Pyrimethamine as a potential pharmacological chaperone for late-onset forms of GM2 gangliosidosis. Journal of Biological Chemistry, 282(12), 9150-9161. https://doi.org/10.1074/jbc.M609304200

Pyrimethamine as a potential pharmacological chaperone for late-onset forms of GM2 gangliosidosis. / Maegawa, Gustavo H B; Tropak, Michael; Buttner, Justin; Stockley, Tracy; Kok, Fernando; Clarke, Joe T R; Mahuran, Don J.

In: Journal of Biological Chemistry, Vol. 282, No. 12, 23.03.2007, p. 9150-9161.

Research output: Contribution to journalArticle

Maegawa, GHB, Tropak, M, Buttner, J, Stockley, T, Kok, F, Clarke, JTR & Mahuran, DJ 2007, 'Pyrimethamine as a potential pharmacological chaperone for late-onset forms of GM2 gangliosidosis', Journal of Biological Chemistry, vol. 282, no. 12, pp. 9150-9161. https://doi.org/10.1074/jbc.M609304200
Maegawa, Gustavo H B ; Tropak, Michael ; Buttner, Justin ; Stockley, Tracy ; Kok, Fernando ; Clarke, Joe T R ; Mahuran, Don J. / Pyrimethamine as a potential pharmacological chaperone for late-onset forms of GM2 gangliosidosis. In: Journal of Biological Chemistry. 2007 ; Vol. 282, No. 12. pp. 9150-9161.
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