Current perspectives on the JAK/STAT signaling pathway and its activating factors in liver fibrosis

The Janus kinase (JAK)/signal transducer and activator of transcription (STAT) signaling pathway is an important signal transduction pathway activated by a variety of cytokines and growth factors and mediates various cellular processes involved in liver fibrosis, including proliferation, differentiation, apoptosis, and inflammation. In this article, the recent findings related to the function of JAK/STAT signaling and its activating factors in liver fibrosis are reviewed. Specifically, the roles of three cytokines leptin, interferon-alpha (IFN-α) and interleukin-4 (IL-4) are detailed in regards to their activation of the intracellular JAK/STAT pathway through the hepatic stellate cell membrane to promote expression of target genes involved in the fibrotic process.