Hepatocyte-targeted lipid nanoparticle for full-length ATP7B mRNA delivery in Wilson disease.

Wilson disease (WD), a copper metabolism disorder caused by ATP7B mutations, requires alternative gene therapies due to the limitations of current treatments such as drug resistance and side effects. Here, we developed a hepatocyte-targeted ATP7B mRNA therapeutic system using a low immunoreactivity lipid nanoparticle (LNP), in which hydroxy-terminated polyethylene glycol lipid (OH-PEG) was utilized to evade human pre-existing anti-PEG antibody recognition and reduce immunogenicity compared with methoxy-terminated polyethylene glycol lipid (MeO-PEG). By optimizing the OH-PEG molar ratio at 3 %, LNP-mediated mRNA expression in hepatocytes increased twofold, while non-target cell expression (Kupffer cells, B cells) decreased by 2 to 6 folds. In vitro studies confirmed ATP7B protein localization to the trans-Golgi network and copper transport functionality. In WD model mice, long-term intervention (6 months) induced reductions in hepatic copper accumulation (up to 72.1 %) in a dose-dependent manner, restored multi-organ copper homeostasis, and normalized ceruloplasmin activity. Safety assessments revealed improved serum biochemical parameters and histopathology, with 95 % of ionizable lipid metabolically cleared within one week after treatment, without allergic reactions or organ toxicity. This study establishes a translatable WD gene therapy platform using a hepatocyte-targeted, low immunoreactivity LNP for full-length ATP7B mRNA delivery, which also serves as an mRNA delivery system for other liver diseases.