Enzyme enhancement activity of N-octyl-β-valienamine on β-glucosidase mutants associated with Gaucher disease

Abstract

Gaucher disease (GD), caused by a defect of beta-glucosidase (beta-Glu), is the most common form of sphingolipidosis. We have previously shown that a carbohydrate mimic N-octyl-beta-valienamine (NOV), an inhibitor of beta-Glu, could increase the protein level and enzyme activity of F213I mutant beta-Glu in cultured GD fibroblasts, suggesting that NOV acted as a pharmacological chaperone to accelerate transport and maturation of this mutant enzyme. In the current study, NOV effects were evaluated in GD fibroblasts with various beta-Glu mutations and in COS cells transiently expressing recombinant mutant proteins. In addition to F213I, NOV was effective on N188S, G202R and N370S mutant forms of beta-Glu, whereas it was ineffective on G193W, D409H and L444P mutants. When expressed in COS cells, the mutant proteins as well as the wild-type protein were localized predominantly in the endoplasmic reticulum and were sensitive to Endo-H treatment. NOV did not alter this localization or Endo-H sensitivity, suggesting that it acted in the endoplasmic reticulum. Profiling of N-alkyl-beta-valienamines with various lengths of the acyl chain showed that N-dodecyl-beta-valienamine was as effective as NOV. These results suggest a potential therapeutic value of NOV and related compounds for GD with a broad range of beta-Glu mutations.

Chaperone Activity of Bicyclic Nojirimycin Analogues for Gaucher Mutations in Comparison with N‐(n‐nonyl)Deoxynojirimycin

“…We have previously demonstrated the effectiveness of chemical chaperone therapy in G M1 -gangliosidosis, [58,59] Gaucher disease [20,21] and Fabry's disease. [60] Notably, we recently found that chaperone therapy can prevent neurological deterioration in a G M1 -gangliosidosis model mouse expressing R201C mutant human b-galactosidase.…”

“…Chemical chaperone activity in Gaucher disease (GD) mutants has been reported for several N-substituted derivatives of the carbasugar b-valienamine [21,46] and of the iminosugar 1-deoxynojirimycin (DNJ), [26,27,47,48] among which the N-(n-nonyl) derivative (NN-DNJ). Recently, we found that bicyclic sp 2 -iminosugar analogues of the parent alkaloid nojirimycin (NJ), with structure of 5-N,6-X-(N'-alkyliminomethylidene)nojirimycin (X represents O, S or N) behaved as very selective competitive inhibitors of b-glucosidases, including human b-glucocerebrosidase.…”

Three classes of glucocerebrosidase inhibitors identified by quantitative high-throughput screening are chaperone leads for Gaucher disease

“…The hypothesized mechanism of action for these compounds is competitive binding to the active site of the mutant enzyme, facilitating proper folding and trafficking to the lysosome, where endogenous substrate displaces the chaperone and enzyme activity is restored (8,13,15). Most GC chaperones studied to date are enzyme inhibitors in the structural class of iminosugars or similar analogs of the natural substrate, glucosylceramide (16)(17)(18)(19)(20)(21)(22)(23)(24)(25). Iminosugars have been shown to increase the cellular activity of the N370S mutant form of GC, as well as of wild-type enzyme (15,26).…”

Gaucher Disease

“…Although an increase in cellular activity has been demonstrated by several groups using a variety of competitive inhibitors [66][67][68][69], the exact mechanism by which these compounds exert their effect is not firmly established. A similar increase in activity can be achieved following treatment of macrophages with NN-DNJ and uptake of Cerezyme through the mannose receptor [70].…”