Virus-induced Hepatic Expression of an Oxidized Phospholipid-binding Antibody Fragment Prevents Initiation of Hepatic Steatosis and Progression to Fibrosis.

Oxidized phospholipids have been implicated in chronic pathologies. It had been shown that hyperlipidemic LDL-R-deficient mice transgenic for a single chain fragment of an oxidized phosphatidylcholine (OxPC)-recognizing IgM E06 (scFv-E06) were protected from developing non-alcoholic fatty liver disease (NAFLD). To investigate the role of OxPCs in initiation of diet-induced hepatic steatosis as well as independently in progression to fibrosis, we used an adeno-associated virus serotype 8 to induce hepatic expression scFv-E06 in a cre-dependent manner (AAV8-scFv-E06) in B6. Speer6-ps1 /J(Alb-cre) mice. Virus-induced expression of scFv-E06 protected mice from diet-induced hepatic steatosis by reducing liver triglyceride content and tissue damage as measured by plasma liver enzymes. Separately, expression of scFv-E06 in mice with established hepatic steatosis prevented the progression to hepatic fibrosis. We developed a targeted, mass spectrometry-based oxophospholipidomic platform to identify and measure OxPC species that were potentially altered by expression of scFv-E06. We discovered that several OxPCs in the plasma were significantly reduced by scFv-E06 expression in both steatosis and fibrosis and identified unique OxPC species that were present in both disease settings. Additionally, we show that the identified OxPC species reduced by scFv-E06 expression dysregulate gene expression and metabolic function of hepatocytes and hepatic stellate cells in vitro. Together, we show that virus-induced hepatic expression of scFv-E06 is sufficient to prevent hepatic steatosis as well as intervene in progression from hepatic steatosis to hepatic fibrosis. Furthermore, we identified unique plasma OxPC species that are reduced by expression of scFv-E06 and may drive initiation of hepatic steatosis and independently progression to hepatic fibrosis. These data demonstrate an important role for individual OxPCs in NAFLD and may provide clinically relevant biomarkers for diagnosis of hepatic steatosis and fibrosis.