Work

TwinPE delivered as RNA or VLP enables precise deletion of GAA repeats in the FXN gene

Year: 2026

Type: article

Abstract: Friedreich’s ataxia (FRDA or FA) is a rare autosomal recessive neurodegenerative disorder caused by guanine-adenine-adenine (GAA) repeat expansions in the first intron of the frataxin ( FXN ) gene. To address this underlying genetic cause, we developed paired prime editors (twinPE) to precisely delete GAA repeats. Using a 38-bp attachment site of bacteria ( attB ) sequence as the reverse transcription template (RTT), we achieved a precise 1.2-kb deletion with attB insertion in HEK293T cells with a 48.0% editing efficiency. We further delivered two synthetic pegRNAs and PE6 mRNA into GM03816 FRDA fibroblasts and GM23404, as well as GM23913 patient-derived induced pluripotent stem cells (iPSCs) via electroporation, achieving average editing rates of 13.3%, 40.6%, and 25.0%, respectively. In both patient-derived iPSCs, twinPE successfully restored FXN expression, resulting in a ∼2-fold increase in mRNA levels, relative to non-treated controls, demonstrating a promising functional correction of gene expression. Importantly, NGS analysis revealed that >95% of all edits were precise, with minimal indels across all tested cell types. We directly delivered twinPE to iPSC-derived motor neurons (iMNs) using virus-like particles (VLPs), achieving 12.6% editing. In summary, our results demonstrate that twinPE enables efficient and precise deletion of GAA repeats across multiple cell types, including iMNs. The restoration of FXN mRNA in iPSCs represents a promising functional recovery, establishing a foundation for twinPE-mediated genome editing as a potential therapeutic strategy for FRDA.

Source: Cell Insight

DOI: 10.1016/j.cellin.2026.100368