Prime Editing Corrects the HBB Codon 8/9 (+G) Mutation in Patient-Derived Induced Pluripotent Stem Cells and Restores β-Globin Expression in iPSC-Derived Erythroid Cells

The genetic mutation HBB codon 8/9 (+G) leads to transfusion-dependent beta-thalassaemia, prevalent in South Asia. Prime editing offers a potential solution for this condition without causing double-strand breaks or incorporating donor DNA. Researchers derived patient-specific induced pluripotent stem cells (iPSCs) and optimized Prime editing for precise correction of the mutation. The experimental design involved comparing patient-derived, treated, and control iPSC-derived erythroid cells using multiple techniques.

The highest success rate was achieved using a precise prime editing setup, resulting in an 8.4% intended-edit frequency. The edited cultures exhibited improved maturation and colony formation, resembling the control cultures more closely. Importantly, the prime editing treatment restored HBB transcript levels and detectable β-globin protein in the iPSC-derived erythroid cells, leading to partial restoration of adult haemoglobin. However, fetal haemoglobin and embryonic globin levels remained predominant in the corrected cells.

While prime editing effectively corrected the HBB c.27dupG mutation in patient iPSCs and restored β-globin expression, it is crucial to validate these findings in additional donors, hematopoietic stem cells, and eventually in vivo. Further research is necessary to fully assess the safety and efficacy of this approach for treating beta-thalassaemia.