Innate immune signaling and gut-liver interactions in nonalcoholic fatty liver disease

Non-alcoholic fatty liver disease (NAFLD) is the hepatic manifestation of the metabolicsyndrome and covers a disease spectrum ranging from steatosis to inflammation, fibrosis, cirrhosis andhepatocellular carcinoma (HCC). The innate immune response in the liver plays an important role duringNAFLD progression. In addition, changes in the intestinal microbial balance and bacterial translocationcan further affect disease progression. Immune cells in the liver recognize cell damage or pathogen invasionwith intracellular or surface-expressed pattern recognition receptors (PRRs), subsequently initiatingsignaling cascades that trigger the release of factors promoting the inflammatory response during NAFLDprogression. Therefore, mechanisms by which cells of the immune system are activated and recruited intothe liver and how these cells cause injury and stress are important for understanding the inflammatoryresponse during NAFLD.