Screening for pharmacological chaperones in Fabry disease

Area of Science:

• Biochemistry
• Genetics
• Pharmacology

Background:

• Fabry disease is a genetic disorder caused by deficient alpha-galactosidase A (alpha-Gal A) enzyme activity.
• Pharmacological chaperone therapy (PCT) aims to increase residual enzyme activity.
• Clinical trials for PCT require methods to predict treatment efficacy for specific mutations.

Purpose of the Study:

• To develop and validate a rapid screening assay for enhancing endogenous alpha-Gal A activity in patient-derived cells.
• To identify Fabry disease mutations that are responsive to 1-deoxygalactonojirimycin (DGJ), a pharmacological chaperone.
• To establish a basis for selecting patients for DGJ therapeutic trials.

Main Methods:

• Utilized a T-cell based system to screen 11 different Fabry disease-causing mutations.
• Exposed patient-derived T-cells carrying these mutations to 1-deoxygalactonojirimycin (DGJ).
• Measured the resulting alpha-galactosidase A (alpha-Gal A) activity in treated cells.

Main Results:

• Alpha-Gal A activity increased to over 50% of normal in several mutations when treated with DGJ.
• Mutations A97V, R112H, R112C, A143T, and L300P showed enhanced enzyme activity, in addition to the previously reported R301Q.
• Mutations R356W, G132R, A143P, R220X, and 30delG did not show significant enhancement of alpha-Gal A activity.

Conclusions:

• The developed assay effectively predicts the enhanceability of alpha-Gal A activity by DGJ in patient-derived cells.
• DGJ demonstrates potential as a therapeutic agent for Fabry disease patients with specific enhanceable mutations.
• This assay methodology has broad applicability for assessing PCT efficacy in other genetic disorders involving enzyme deficiencies.