Functional microRNA screening to improve hepatocyte formation via direct reprogramming

Liver failure is one of the leading causes of death worldwide. Due to a shortage of organ donors, it is of utmost importance to pursue readily available sources of hepatocytes. Induced hepatocyte-like cells (iHeps) reprogrammed from fibroblasts may serve as a valuable option for cell therapy of liver diseases. However, the cells obtained do not mimic the characteristics of adult primary hepatocytes for cell-based therapies. In order to improve the reprogramming, we performed functional microRNA screening during cell fate conversion of murine embryonic fibroblasts into hepatocytes. First, murine embryonic fibroblasts were transduced with a lentiviral vector expressing FOXA3, GATA4, HNF1A and HNF4A transcription factors. Afterwards, mimics for 302 conserved miRNAs were transfected in developing iHEPs during direct reprogramming. Hepatogenic potential of miRNA mimics was determined by their influence on the secretion of albumin and alpha-1 antitrypsin. We identified 6 microRNAs that are capable of enhancing direct reprogramming of murine embryonic fibroblasts into iHeps. In summary, microRNA modulation is potential promising approach to improve hepatocyte formation via direct reprogramming.