In vivo base editing alleviates hepatic iron accumulation and fibrosis in models of HFE-related hereditary hemochromatosis.

BACKGROUND & AIMS: HFE-related hereditary hemochromatosis is caused by loss-of-function mutations in the HFE gene, leading to excessive intestinal iron absorption and hepatic deposition. The C282Y variant in homozygosity accounts for 80-90% of diagnosed cases. If untreated, iron accumulation can cause liver fibrosis, cirrhosis, and hepatocellular carcinoma.

METHODS

We employed lipid nanoparticles (LNPs) to deliver base editor mRNA and single-guide RNA for in vivo correction of the HFE C282Y mutation in a murine model under iron challenge. Additionally, patient-derived induced pluripotent stem cells (iPSCs) and hepatocyte-like cells were edited using the same approach.

RESULTS

Base editing achieved a conversion rate of 73.6 ± 4.9% in cultured murine hepatocytes and up to 67% in vivo. No off-target effects were detected at genomic sites with one or two mismatches, as confirmed by next-generation sequencing. Treated mice showed significantly reduced hepatic iron overload despite continued high dietary iron intake. Transcriptomic analysis revealed decreased signatures associated with fibrosis and cancer. For preclinical evaluation, iPSCs from C282Y homozygous patients were differentiated into hepatocyte-like cells. LNP-mediated base editing achieved up to 63.8 ± 0.8% correction in these cells, again without detectable off-target activity.

CONCLUSIONS

These results provide proof of concept that base editing of the C282Y variant is both safe and efficient in vivo and in human-derived cells, effectively reducing hepatic iron accumulation and preventing fibrotic remodeling.

IMPACT AND IMPLICATIONS: HFE C282Y-related hemochromatosis lacks causal therapies and carries a risk of iron-driven liver disease, supporting the need for precise in vivo gene correction. Here, LNP-mediated adenine base editor delivery enabled efficient editing in hepatocytes and induced pluripotent stem cell-derived models, reducing hepatic iron and normalizing biomarkers without detectable safety concerns. These findings highlight translational potential for non-viral gene correction, though further validation in larger and long-term studies is required.