Prime editing to Repair Inherited Metabolic Errors: in vivo gene correction for human genetic disease

Introduction

Treatment options are insufficient for the majority of genetic metabolic diseases. Methylmalonic acidemia (MMA) is one such severe metabolic disease. With current therapeutic strategies, patients still develop metabolic decompensations, brain damage, kidney failure, and have a lifelong risk to acutely become blind.

Background

Repair of the genetic cause of disease would revolutionize outcomes for these patients, especially with increasing detection in neonatal screening programs. This makes it possible to correct the cause of disease prior to the onset of irreversible damage. However, efficiency, safety, versatility, and delivery of precise gene editing is not yet sufficient for in vivo gene-correction therapies.

Project Aim

The aim of this proposal is to develop an in vivo gene-editing therapy program for patients with metabolic diseases targeting the liver, where most metabolic genes are highly expressed. As a proof-of-principle, I will repair genetic causes of MMA, validate this in personalized cells and mouse models, and lay the groundwork for human trials.

Objectives

To this end, I will:

1. Generate a clinically applicable gene-editing technique. I recently demonstrated that the novel gene-editing technique prime editing could accurately correct different mutations in patient-derived organoids. Using an innovative reporter and patient-derived organoids, I will develop prime editing into an efficient and safe strategy that can correct >90% of patient mutations.

2. Create a system for in vivo delivery of the prime-editing machinery. This will involve using lipid nanoparticles to target the liver, utilizing patient-derived liver organoids and an existing MMA mouse model.

3. Develop a roadmap to tailor gene-correction therapies to individual patients. This will involve using the reporter with the patient mutation and mutational context, patient-derived organoids, and a mutation-specific animal model for a common MMA mutation.

Conclusion

This foundational work will lay the basis for broad clinical application of precise gene-editing therapies.