Objective: To identify novel non-inhibitory allosteric correctors of GCase using Congruence Therapeutic’s in silico proprietary drug discovery engine, Revenir™

Background: GBA1 encoding for glucocerebrosidase (GCase) represents the most frequent large-effect genetic factor associated with Parkinson’s disease (GBA1-PD).  Multiple GBA1 mutations in a heterozygous state with WT GCase are associated with elevated GBA-PD risk and a more severe PD phenotype compared to idiopathic PD.  A growing body of evidence indicates that increased GCase misfolding in the endoplasmic reticulum and low GCase activity are pathophysiological drivers in GBA1-PD by promoting glycolipid accumulation, neuroinflammation, and α-synuclein polymerization. Small molecule allosteric GCase correctors, which promotes GCase activity is a promising therapeutic approach for GBA1-PD.

Method: Our proprietary in silico drug discovery engine Revenir™ was used to screen GCase for the identification of allosteric correctors. Protein conformational ensembles of GCase were used to identify novel allosteric pockets and to generate pharmacophore models. A suite of biological assays was developed and validated using reference compounds to quantify GCase activity and lysosomal trafficking. A biochemical assay using recombinant human GCase was used to monitor enzymatic activity with the natural substrate glucosylceramide. Furthermore, a combination of genetically engineered cells and patient-derived cells were used to track lysosomal GCase activity in live cells as well as trafficking from the ER to the lysosome.

Results: A virtual library of small molecules was screened in silico and selected hits were evaluated using our machine learning model for reduced pathogenicity against L444P and N370S variants. Selected hits from Revenir™ were synthesized and characterized to confirm their biological activity.   We successfully identified brain-penetrant hits (Kp, mouse: 0.5 – 2.0), from multiple chemical series, which increased lysosomal GCase activity (4-8 fold) in WT and GBA mutant cell lines/patient derived cells without inhibiting GCase in natural substrate biochemical assays (IC50 > 30 uM). Some of these molecules also promoted GCase translocation to lysosomes by >1.5 fold.

Conclusion: Revenir™ was able to identify structurally diverse allosteric correctors of GCase. Optimization of these chemical leads is ongoing to discover potential clinical candidates.

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MDS Abstracts - https://www.mdsabstracts.org/abstract/identification-of-allosteric-gcase-correctors-using-revenir-for-the-treatment-of-gba1-parkinsons-disease/