Visualization of Endogenous Hypochlorite in Drug-Induced Liver Injury Mice via a Bioluminescent Probe Combined with Firefly Luciferase mRNA-Loaded Lipid Nanoparticles

Drug-induced liver injury (DILI) is a common liver disease with a high rate of morbidity, and its pathogenesis is closely associated with the overproduction of highly reactive hypochlorite (ClO–) in the liver. However, bioluminescence imaging of endogenous hypochlorite in nontransgenic natural mice remains challenging. Herein, to address this issue, we report a strategy for imaging ClO– in living cells and DILI mice by harnessing a bioluminescent probe formylhydrazine luciferin (ClO-Luc) combined with firefly luciferase (fLuc) mRNA-loaded lipid nanoparticles (LNPs). LNPs could efficiently deliver fLuc mRNA into living cells and in vivo, expressing abundant luciferase in the cytoplasm in situ. In the presence of ClO–, probe ClO-Luc locked by formylhydrazine could release cage-free d-luciferin through oxidation and follow-up hydrolysis reactions, further allowing for bioluminescence imaging. Moreover, based on the luciferase–luciferin system, it was able to sensitively and selectively detect ClO– in vitro with a limit of detection of 0.59 μM and successfully monitor the endogenous hypochlorite generation in the DILI mouse model for the first time. We postulate that this work provides a new method to elucidate the roles of ClO– in related diseases via bioluminescence imaging.