Osteopontin: a new player in regulating hepatic ductular reaction and hepatic progenitor cell responses during chronic liver injury

In recent years, an increasing number of reports have shown the involvement of osteopontin (OPN), a pleiotropic cytokine and an important component of the extracellular matrix (ECM), in the pathogenesis of liver injury and the development of fibrosis.1 2 OPN is also frequently overexpressed in hepatocellular carcinoma (HCC), where it modulates HCC growth, invasion and metastasis,2 and in cholangiocarcinoma, where its expression bears prognostic significance. Previous studies3 have shown that in injured livers OPN is expressed by hepatic stellate cells (HSC) and upregulates collagen I production. Interestingly, in HSC, OPN expression appears to be downstream of SOX9, a Hedgehog- and Notch-controlled transcription factor that is expressed also in biliary cells and hepatic progenitor cells (HPC)/hepatocytes committed to the biliary fate.4–6 In this issue of Gut, two papers investigate the role of OPN in HPC-driven ductular...
Source: Gut - Category: Gastroenterology Authors: Tags: Commentary Source Type: research