A major challenge in the field of Gaucher disease has been the development of new therapeutic strategies including molecular chaperones. All previously described chaperones of glucocerebrosidase are enzyme inhibitors, which complicates their clinical development, because their chaperone activity must be balanced against the functional inhibition of the enzyme. Using a novel high throughput screening methodology, we identified a chemical series that does not inhibit the enzyme, but can still facilitate its translocation to the lysosome as measured by immunostaining of glucocerebrosidase in patient fibroblasts. These compounds provide the basis for the development of a novel approach towards small molecule treatment for patients with Gaucher disease.

Although a group of FDA-approved drugs were previously identified with activity against Ebola virus, most of them are not clinically useful because their human blood concentrations are not high enough to inhibit EBOV infection. We screened 795 unique three-drug combinations in an EBOV entry assay. Two sets of three-drug combinations, toremifene-mefloquine-posaconazole and toremifene-clarithromycin-posaconazole, were identified that effectively blocked EBOV entry and were further validated for inhibition of live EBOV infection. The individual drug concentrations in the combinations were reduced to clinically relevant levels. We identified mechanisms of action of these drugs: functional inhibitions of Niemann–Pick C1, acid sphingomyelinase, and lysosomal calcium release. Our findings identify the drug combinations with potential to treat EBOV infection.

Gaucher disease (GD), the most common lysosomal storage disorder, results from the inherited deficiency of the lysosomal enzyme glucocerebrosidase (GCase). Previously, wildtype GCase was used for high throughput screening (HTS) of large collections of compounds to identify small molecule chaperones that could be developed as new therapies for GD. However, the compounds identified from HTS usually showed reduced potency later in confirmatory cell-based assays. An alternate strategy is to perform HTS on mutant enzyme to identify different lead compounds, including those enhancing mutant enzyme activities. We developed a new screening assay using enzyme extract prepared from the spleen of a patient with Gaucher disease with genotype N370S/N370S. In tissue extracts, GCase is in a more native physiological environment, and is present with the native activator saposin C and other potential cofactors. Using this assay, we screened a library of 250,000 compounds and identified novel modulators of mutant GCase including 14 new lead inhibitors and 30 lead activators. The activities of some of the primary hits were confirmed in subsequent cell-based assays using patient-derived fibroblasts. These results suggest that primary screening assays using enzyme extracted from tissues is an alternative approach to identify high quality, physiologically relevant lead compounds for drug development.