Fig. 1

Schematic representation of the synthetic B18R mRNA transfection and translation process and the inhibition of type I interferon (IFN) immune response. (a) Lipoplexes are generated by complexing the B18R encoding mRNA with Lipofectamine^® 2000. After the uptake of lipoplexes into the cells by endocytosis and the subsequent endosomal escape, the synthetic B18R mRNA is translated by the ribosomes into functional B18R protein. Then, B18R is released into the supernatant or integrated into the cell membrane. (b) The recognition of synthetic mRNA by pattern recognition receptors (PRRs) in the cells leads to the activation of NF-κB, IRF3, and IRF7, which results in the expression of pro-inflammatory cytokines, e.g. type I IFNs. The produced type I IFNs bind to the IFN receptors and induce the expression of interferon-stimulated genes (ISGs), such as Mx1. The synthesized B18R proteins can capture type I IFNs produced by mRNA transfected cells, and thereby, reduce the inflammatory reaction