Hyperuricemia is associated with an increased risk of gout, hypertension, diabetes, and cardiovascular diseases. Most mammals maintain normal serum uric acid (SUA) via urate oxidase (Uox), an enzyme that metabolizes poorly-soluble UA to highly-soluble allantoin. In contrast, Uox became a pseudogene in humans and apes over the long course of evolution. Here we demonstrate an atavistic strategy for treating hyperuricemia based on endogenous expression of Uox in hepatocytes mediated by mRNA (mUox) loaded with an ionizable lipid nanoparticle termed iLAND. mUox@iLAND allows effective transfection and protein expression in vitro. A single dose of mUox@iLAND lowers SUA levels for several weeks in two female murine models, including a novel long-lasting model, which is also confirmed by metabolomics analysis. Together with the excellent safety profiles observed in vivo, the proposed mRNA agent demonstrates substantial potential for hyperuricemia therapy and the prevention of associated conditions.

Urate oxidase (Uox) lost its function during evolution. Here the authors propose an atavistic strategy to treat hyperuricemia by using a proprietary lipid nanoparticle to load Uox mRNA, which reduced the serum uric acid levels effectively in two animal models.