Effect of cationic amphiphilic drugs on mRNA lipoplex-induced protein expression

In this study, we investigated the impact of cationic amphiphilic drugs (CADs) on in vitro and in vivo protein expression following administration of mRNA lipoplexes. The mRNA lipoplexes were formulated using a modified ethanol injection method and applied to human hepatoma HuH-7 cells, human prostate cancer PC-3 cells, and DC2.4 mouse dendritic cells in the presence of various CADs: ebastine (EBS), loperamide (LPM), carvedilol (CVD), nortriptyline (NRT), desloratadine (DSL), and chloroquine (CQ). In vitro, high luciferase (Luc) expression was induced by Luc mRNA lipoplexes in the presence of EBS, LPM, or CVD, whereas similar effects were not observed with NRT, DSL, or CQ. This enhanced expression was attributed to inhibition of lysosomal acidification rather than changes in cellular uptake or mRNA translation efficiency. Intravenous administration of Luc mRNA lipoplexes into the tail vein of mice increased Luc activity in the lungs and spleen; co-administration with EBS or CVD further increased protein expression in the lungs without affecting expression in the spleen. Furthermore, induction of ovalbumin (OVA)-specific antibodies by OVA mRNA lipoplex administration was suppressed by EBS, attributed to reduced TNF-α production in the spleen, whereas CVD did not elicit similar effects. These findings suggest that EBS and CVD promote mRNA lipoplex-mediated protein expression in cultured cells and mouse lung tissue. However, EBS also diminishes antibody responses triggered by mRNA lipoplexes. Accordingly, caution is warranted when administering lipid-based mRNA vaccines to patients taking CADs, as these drugs may influence vaccine efficacy and safety.