Synthesis and Evaluation of Hybrid Structures Composed of Two Glucosylceramide Synthase Inhibitors

Glucosylceramide metabolism and the enzymes involved have attracted significant interest in medicinal chemistry, because aberrations in the levels of glycolipids that are derived from glucosylceramide are causative in a range of human diseases including lysosomal storage disorders, type2 diabetes, and neurodegenerative diseases. Selective modulation of one of the glycoprocessing enzymes involved in glucosylceramide metabolism - glucosylceramide synthase (GCS), acid glucosylceramidase (GBA1), or neutral glucosylceramidase (GBA2) - is therefore an attractive research objective. In this study we took two established GCS inhibitors, one based on deoxynojirimycin and the other a ceramide analogue, and merged characteristic features to obtain hybrid compounds. The resulting 39-compound library does not contain new GCS inhibitors; however, a potent (200nm) GBA1 inhibitor was identified that has little activity toward GBA2 and might therefore serve as a lead for further biomedical development as a selective GBA1 modulator. Taking the best of both: Two established glucosylceramide synthase (GCS) inhibitors were merged via convergent synthesis to obtain hybrid compounds. Members of this 39-compound library have characteristics of both parent GCS inhibitors. No new GCS inhibitors were established, but a potent (200nm) acid glucosylceramidase (GBA1) inhibitor was identified. This adamantanemethyloxypenanoic acid pyrrolidene-substituted derivative of eliglustat can serve as a lead for further biomedical development of selective GBA1 modulators.