Synthesis of a New β-Galactosidase Inhibitor Displaying Pharmacological Chaperone Properties for GM1 Gangliosidosis

Abstract

GM1 gangliosidosis is a rare lysosomal disease caused by the deficiency of the enzyme β-galactosidase (β-Gal; GLB1; E.C. 3.2.1.23), responsible for the hydrolysis of terminal β-galactosyl residues from GM1 ganglioside, glycoproteins, and glycosaminoglycans, such as keratan-sulfate. With the aim of identifying new pharmacological chaperones for GM1 gangliosidosis, the synthesis of five new trihydroxypiperidine iminosugars is reported in this work. The target compounds feature a pentyl alkyl chain in different positions of the piperidine ring and different absolute configurations of the alkyl chain at C-2 and the hydroxy group at C-3. The organometallic addition of a Grignard reagent onto a carbohydrate-derived nitrone in the presence or absence of a suitable Lewis Acid was exploited, providing structural diversity at C-2, followed by the ring-closure reductive amination step. An oxidation-reduction process allowed access to a different configuration at C-3. The N-pentyl trihydroxypiperidine iminosugar was also synthesized for the purpose of comparison. The biological evaluation of the newly synthesized compounds was performed on leucocyte extracts from healthy donors and identified two suitable β-Gal inhibitors, namely compounds 10 and 12. Among these, compound 12 showed chaperoning properties since it enhanced β-Gal activity by 40% when tested on GM1 patients bearing the p.Ile51Asn/p.Arg201His mutations.

Identification of GM1-Ganglioside Secondary Accumulation in Fibroblasts from Neuropathic Gaucher Patients and Effect of a Trivalent Trihydroxypiperidine Iminosugar Compound on Its Storage Reduction

“…The compound CV82 showed a negligible percentage of inhibition (33% at 1 mM; Figure 4 A), demonstrating its complete selectivity against the GCase enzyme with respect to the β-Gal enzyme. It is worth noting that the best inhibitory activity does not always correspond to the best chaperone activity on cell lines, as already observed for a series of compounds [ 22 ]. Therefore, we tested the ability of the CV82 compound to increase the β-Gal enzyme activity in the fibroblasts wild type ( Figure 4 B) and with the p.Arg201His/p.Tyr83LeufsX8 and p.Arg201His/p.Ile51Asn mutations from juvenile GM1 patients ( Figure 4 C,D).…”

Glycosidase-targeting small molecules for biological and therapeutic applications

“…23). 191 Nonetheless, a study using fibroblasts from juvenile GM1-gangliosidosis patients showed that 59 rescues the activity of b-galactosidase (40% at 600 mM) in diseased cells.…”

Neurological Disease Modeling Using Pluripotent and Multipotent Stem Cells: A Key Step Towards Understanding and Treating Mucopolysaccharidoses

“…This drug is currently being used in the clinic for a significant number of Fabry disease patients, all harboring missense mutations that cause misfolding of -galactosidase, and has been shown to improve the associated cardiac and renal symptoms [36,37]. And, while no other chaperone molecule has reached the clinic so far, several studies are being performed in other LSDs [38][39][40][41][42].…”