DUSP9 and Hepatic fibrosis: Despite these apparently contradictory results, a recent study in which conditional liver-specific deletion of DUSP9/MKP-4 was used to study the response to a high fat diet has demonstrated that loss of DUSP9/MKP-4 in the liver sensitises animals to hepatic steatosis and inflammatory responses and that DUSP9 deficiency aggravated high fat, high cholesterol (HFHC)-induced liver fibrosis [181].