Prime editing gene-correction therapy for PFIC1 and PFIC3 in patient-derived liver organoids

Overview

Progressive familial intrahepatic cholestasis (PFIC) is a severe group of inherited liver disorders caused by mutations in genes such as ATP8B1 (PFIC1) and ABCB4 (PFIC3). Current treatment options are limited and often inadequate, particularly for PFIC1 and PFIC3, leaving patients at risk of progressive liver damage and failure. This project develops a gene-correction therapy using prime editing, a precise gene-editing technology, delivered to liver cells via modified RNA (modRNA) packaged in lipid nanoparticles (LNPs). Because correcting as little as 5–10% of liver cells may be sufficient to produce a therapeutic benefit, this approach could offer a permanent, one-time cure for PFIC patients.

Technical specifications

Key features:

• Prime editing machinery designed to correct the PFIC1-causing ATP8B1 p.R600Q mutation and the PFIC3-causing ABCB4 p.E1012X mutation
• A proprietary fluorescent prime editing and enrichment reporter (fluoPEER) used to optimize editing efficiency
• modRNA production via in vitro transcription using advanced T7 polymerases and capping strategies to maximize expression and editing performance
• Liver-targeted LNP delivery, including evaluation of novel lipid formulations such as beta-sitosterol replacement of cholesterol for improved hepatic uptake
• Validation in patient-derived liver organoids from an established biobank, with amplicon sequencing to assess on-target and off-target genetic effects
• Optional in vivo testing in a PFIC1 mouse model carrying the relevant point mutation

How it works:

Prime editing uses a fusion protein and a prime editing guide RNA (pegRNA) to make precise, targeted corrections to DNA without introducing double-strand breaks. The editing machinery is encoded as modRNA, which is transient and avoids the long-term expression risks associated with DNA-based editors. LNPs encapsulate the modRNA and deliver it to liver cells, where the editing machinery corrects the disease-causing mutation. The corrected cells can restore normal bile acid transport, potentially halting or reversing disease progression.

Technology readiness level

The project is at an advanced preclinical stage. Initial prime-editing designs for both target mutations have demonstrated relatively high editing efficiency, and LNP delivery of prime-editing modRNAs has shown editing performance comparable to electroporation-delivered DNA in cell lines. Patient-derived liver organoids carrying the relevant PFIC mutations are already available in the team's biobank for testing. Remaining work focuses on optimizing editing efficiency, refining LNP formulations for liver delivery, and validating the therapy in organoid models, with optional in vivo studies in a PFIC1 mouse model pending additional funding. The approach is positioned for translational development toward clinical application in genetic liver disease.