Lipid nanoparticle-targeted mRNA formulation as a treatment for ornithine-transcarbamylase deficiency model mice

Kazuto Yamazaki; Kenji Kubara; Satoko Ishii; Keita Kondo; Yuta Suzuki; Takayuki Miyazaki; Kaoru Mitsuhashi; Masashi Ito; Kappei Tsukahara

doi:10.1016/j.omtn.2023.06.023

Lipid nanoparticle-targeted mRNA formulation as a treatment for ornithine-transcarbamylase deficiency model mice

Mol Ther Nucleic Acids. 2023 Jul 4:33:210-226. doi: 10.1016/j.omtn.2023.06.023. eCollection 2023 Sep 12.

Authors

Kazuto Yamazaki¹, Kenji Kubara¹, Satoko Ishii¹, Keita Kondo¹, Yuta Suzuki¹, Takayuki Miyazaki¹, Kaoru Mitsuhashi¹, Masashi Ito¹, Kappei Tsukahara¹

Affiliation

¹ Tsukuba Research Laboratories, Eisai Co., Ltd., 5-1-3, Tokodai, Tsukuba, Ibaraki 300-2635, Japan.

Abstract

Ornithine transcarbamylase (OTC) plays a significant role in the urea cycle, a metabolic pathway functioning in the liver to detoxify ammonia. OTC deficiency (OTCD) is the most prevalent urea cycle disorder. Here, we show that intravenously delivered human OTC (hOTC) mRNA by lipid nanoparticles (LNP) was an effective treatment for OTCD by restoring the urea cycle. We observed a homotrimer conformation of hOTC proteins produced by the mRNA-LNP in cells by cryo-electron microscopy. The immunohistochemistry revealed the mitochondria localization of produced hOTC proteins in hepatocytes in mice. In livers of mice intravenously injected with hOTC-mRNA/LNP at 1.0 mg/kg, the delivered hOTC mRNA levels steeply decreased with a half-life (t_1/2) of 7.1 h, whereas the produced hOTC protein levels retained for 5 days and then declined with a t_1/2 of 2.2 days. In OTCD model mice (high-protein diet-fed Otc^spf-ash hemizygous males), a single dose of hOTC-mRNA/LNP at 3.0 mg/kg ameliorated hyperammonemia and weight loss with prolonged survival rate (22 days) compared with that of untreated mice (11 days). Weekly repeated doses at 0.3 and 1.0 mg/kg were well tolerated in wild-type mice and showed a dose-dependent amelioration of survival rate in OTCD mice, thus, showing the therapeutic potential of LNP-formulated hOTC mRNA for OTCD.

Keywords: MT: delivery strategies: ornithine transcarbamylase; Otcspf-ash mice; cryo-electron microscopy; homotrimer conformation; lipid nanoparticles; messenger RNA therapy; mitochondria localization.