Use of Nucleoside Modified mRNA Encoding Regenerative Factors Encapsulated with Lipid Nanoparticles to Alleviate Acute and Chronic Murine Liver Diseases.

The remarkable ability of the liver to regenerate by proliferation of mature hepatocytes constitutes the first mechanism of repair commonly named the hepatocyte-driven regeneration. Yet, during chronic liver injury or acute severe hepatocyte death, proliferation of mature cells becomes exhausted. In these cases, alternative precursors of hepatocytes that derive from cholangiocytes have been identified in both human and rodent diseased livers. They are presently growing evidence of conversion of these cholangiocytes into hepatocytes as defined as the cholangiocyte-driven regeneration. Despite these two mechanisms of liver repair, end stage liver disease remains the 12 most common cause of death in the United States, begging for therapeutic strategies to harness mechanisms of liver regeneration. Here we demonstrate that delivery via nucleoside modified mRNA complexed to lipid nanoparticles (mRNA-LNP) to the liver of the key hepatocyte mitogen hepatocyte growth factor (HGF) and epidermal growth factor (EGF) enhance hepatocyte-driven repair, while delivery of vascular endothelial growth factor A (VEGFA) mRNA-LNP promotes cholangiocyte-driven repair. We confirm specific hepatotropism of mRNA-LNP via intravenous injection of firefly luciferase encoding mRNA-LNP, with protein expression lasting about 3 days. In the liver, virtually all hepatocytes are transfected along with a subpopulation of endothelial and Kupffer cells. In homeostasis, HGF mRNA-LNP efficiently induce hepatocyte proliferation. In a chronic liver injury mouse model recapitulating non-alcoholic fatty liver disease, injections of both HGF and EGF mRNA-LNP sharply reverse steatosis and accelerate restoration of liver function. Likewise, HGF and EGF mRNA-LNP accelerate liver regeneration after acetaminophen-induced acute liver injury with rapid return to baseline alanine transaminase (ALT) levels. Transient delivery of VEGFA in acute and chronic injured mouse livers via mRNA-LNP induces robust cholangiocyte conversion to hepatocytes as well as reversion of steatosis and fibrosis. This study introduces mRNA-LNP as a potentially translatable safe therapeutic intervention to harness both hepatocyte- and cholangiocyte-driven liver regeneration to ultimately treat human acute and chronic liver diseases.