Enhancing Lipid Nanoparticle-Mediated Circular RNA and mRNA Expression in the Placenta through Inhibition of IFNAR-JAK-STAT Signaling
Hannah C. Safford, Hannah C. Geisler, Ajay S. Thatte, Kuo-Chieh Liao, Alexandre Poirier, Marshall Padilla, Hannah M. Yamagata, Anushka Agrawal, Amanda M. Murray, Alex G. Hamilton, Kelsey L. Swingle, Emily Fitzgerald, Ori Chalom, Yue Wan, Michael J. MitchellAbstract
The placenta has emerged as a promising target for RNA lipid nanoparticle (LNP)-based therapies to treat obstetric complications, yet efficient extrahepatic RNA transfection remains a challenge. Here, we identify innate immune signaling as a regulator of placental RNA translation and demonstrate that inhibition of IFN-α/β receptor (IFNAR) and JAK-STAT signaling enhances LNP-mediated transgene expression in the placenta for both messenger RNA (mRNA) and circular RNA (circRNA). While a placenta-tropic LNP enabled robust and durable circRNA expression in trophoblasts in vitro, circRNA translation was substantially decreased in vivo compared to mRNA in pregnant mice. Inhibition of IFNAR-JAK-STAT signaling enhanced circRNA translation up to 12-fold in maternal organs and increased circRNA and mRNA translation in the placenta up to 17.5- and 4-fold, respectively. JAK-STAT inhibition also enhanced translation of therapeutically relevant VEGF-encoding circRNA and mRNA in pregnant mice, suggesting innate immune modulation as a broadly applicable strategy to improve RNA therapeutics during pregnancy.