Discovery of Phospholipase D Inhibitors with Improved Drug-likeProperties and Central Nervous System Penetrance br

Phospholipase D (PLD) is a phospholipase enzymeresponsible for hydrolyzing phosphatidylcholine into the lipidsignaling molecule, phosphatidic acid, and choline. From atherapeutic perspective, PLD has been implicated in humancancer progression as well as a target for neurodegenerativediseases, including Alzheimer's. Moreover, knockdown of PLDrescues the ALS phenotype in multipleDrosophilamodels of ALS(amyotrophic lateral sclerosis) and displays modest motor benefitsin an SOD1 ALS mouse model. To further validate whetherinhibiting PLD is beneficial for the treatment of ALS, a brainpenetrant small molecule inhibitor with suitable PK properties to test in an ALS animal model is needed. Using a combination ofligand-based drug discovery and structure-based design, a dual PLD1/PLD2 inhibitor was discovered that is single digit nanomolarin the Calu-1 cell assay and has suitable PK properties forin vivostudies. To capture thein vivomeasurement of PLD inhibition, atransphosphatidylation pharmacodynamic LC-MS assay was developed, in which a dual PLD1/PLD2 inhibitor was found to reducePLD activity by 15-20-fold.