Lineage-tracing methods and the kidney. Kidney Int. 2014;86:481-488. [PMID: 24088959 DOI: 10.1038/ki.2013.368.24088959]

Cell lineage tracing in study of epithelial-to-mesenchymal transition during hepatic fibrosis

Hepatic fibrosis is the common pathologic process of chronic liver injury. Early studies mostly used immunohistochemistry to assess the role of epithelial-to-mesenchymal transition (EMT) in human or animal liver repair, and several types of liver cells including hepatocytes, cholangiocytes, hepatic stellate cells (HSCs) and liver progenitor cells have been shown to undergo EMT during hepatic fibrosis. However, this technique has several flaws. In recent years, with the rapid development of genetic engineering, especially the application of the recombinant enzyme Cre/loxP system, cell lineage tracing is becoming a popular and powerful tool to overcome the limitations of immunostaining for identifying EMT during hepatic fibrosis. Since this technique genetically labels cells, the marker will be present in any progeny of the labeled cells. Many groups have generated different lineages of double transgenic (DTG) mice and utilized different models of hepatic injury to investigate whether EMT contributes to hepatic injury or not. The purpose of this article is to summarize evidence, which is obtained using lineage cell tracing, for and against the possibility that EMT is involved in hepatic fibrosis.