Protein is expressed in all major organs after intravenous infusion of mRNA-lipid nanoparticles in swine

Abstract

In vivo delivery of mRNA is promising for the study of gene expression and the treatment of diseases. Lipid nanoparticles (LNP) enable efficient delivery of mRNA constructs, but protein expression has been assumed to be limited to the liver. With specialized LNP, delivery to extrahepatic tissue occurs in small animal models, however it is unclear if global delivery of mRNA to all major organs is possible in humans, because delivery may be affected by differences in innate immune response and relative organ size. Furthermore, limited studies with LNP have been performed in large animal models, such as swine, due to their sensitivity to complement activation-related pseudoallergy (CARPA). In this study, we found that exogenous protein expression occurred in all major organs when swine were injected intravenously with a relatively low dose of mRNA encapsulated in a clinically relevant LNP formulation. Exogenous protein was detected in the liver, spleen, lung, heart, uterus, colon, stomach, kidney, small intestine, and brain of the swine without inducing CARPA. Furthermore, protein expression was detected in the bone marrow, including megakaryocytes, hematopoietic stem cells, granulocytes, and in circulating white blood cells and platelets. These results show that nearly all major organs contain exogenous protein expression and are viable targets for mRNA therapies.