MicroRNAs: Crucial Players in the Differentiation of Human Pluripotent and Multipotent Stem Cells into Functional Hepatocyte-Like Cells.

Hepatic disease negatively impacts liver function and metabolism. Primary human hepatocytes are the gold standard for the prediction and successful treatment of liver disease. However, the sources of hepatocytes for drug toxicity testing and disease modeling are limited. To overcome this issue, pluripotent stem cells (PSCs) have emerged as an alternative strategy for liver disease therapy. Human PSCs, including embryonic stem cells (ESC) and induced pluripotent stem cells (iPSC) can self-renew and give rise to all cells of the body. Human PSCs are attractive cell sources for regenerative medicine, tissue engineering, drug discovery, and developmental studies. Several recent studies have shown that mesenchymal stem cells (MSCs) can also differentiate (or trans-differentiate) into hepatocytes. Differentiation of human PSCs and MSCs into functional hepatocyte-like cells (HLCs) opens new strategies to study genetic diseases, hepatotoxicity, infection of hepatotropic viruses, and analyze hepatic biology. Numerous in vitro and in vivo differentiation protocols have been established to obtain human PSCs/MSCs-derived HLCs and mimic their characteristics. It was recently discovered that microRNAs (miRNAs) play a critical role in controlling the ectopic expression of transcription factors and governing the hepatocyte differentiation of human PSCs and MSCs. In this review, we focused on the role of miRNAs in the differentiation of human PSCs and MSCs into hepatocytes.