Effects of GC inhibitors on enzyme activity and trafficking in fibroblasts from patients with Gaucher disease (genotype N370S/N370S) and from control subjects (WT). (A) Percentage change in GC activity. Fibroblast lines DMN 87.30 (N370S) and GM5659 (WT) treated with compounds at either 13.3 or 40 μM were assayed for GC activity, as described in Methods. Data represent three independent experiments performed with three replicates per sample. Error bars are SEM. (B) Dual labeling with polyclonal GC antibody (GC Ab, red) and a lysosomal marker (LysoTracker, green) in untreated WT (GM 3348) and N370S (DMN 87.30) fibroblasts and in the N370S line treated with 40 μM compound 1. Overlay images demonstrating colocalization (yellow) of GC Ab with the lysosomal marker indicate potential improvement in GC trafficking. (C) Immunofluorescence staining of two N370S mutant fibroblast lines, DMN 83.137 and DMN 87.30, grown with 40 μM compounds. Cells were costained with GC Ab and LysoTracker as in B. Overlay images are shown for cells treated with DMSO (control), 5 (nonyl-DNJ), active compounds 1, 2, and 3, and 22, an inactive compound. Although there is some lysosomal colocalization in both cell lines, compound 1 and, to a lesser extent, compound 3, which significantly increased GC activity in the cell-based assay, show increased yellow fluorescence, demonstrating an increase of GC in the lysosomal compartment.