• Direct conversion of porcine primary fibroblasts into hepatocyte-like cells.

      Fráguas-Eggenschwiler, Mariane; Eggenschwiler, Reto; Söllner, Jenny-Helena; Cortnumme, Leon; Vondran, Florian W R; Cantz, Tobias; Ott, Michael; Niemann, Heiner; HZI,Helmholtz-Zentrum für Infektionsforschung GmbH, Inhoffenstr. 7,38124 Braunschweig, Germany. (Nature Research, 2021-04-29)
      The pig is an important model organism for biomedical research, mainly due to its extensive genetic, physiological and anatomical similarities with humans. Until date, direct conversion of somatic cells into hepatocyte-like cells (iHeps) has only been achieved in rodents and human cells. Here, we employed lentiviral vectors to screen a panel of 12 hepatic transcription factors (TF) for their potential to convert porcine fibroblasts into hepatocyte-like cells. We demonstrate for the first time, hepatic conversion of porcine somatic cells by over-expression of CEBPα, FOXA1 and HNF4α2 (3TF-piHeps). Reprogrammed 3TF-piHeps display a hepatocyte-like morphology and show functional characteristics of hepatic cells, including albumin secretion, Dil-AcLDL uptake, storage of lipids and glycogen and activity of cytochrome P450 enzymes CYP1A2 and CYP2C33 (CYP2C9 in humans). Moreover, we show that markers of mature hepatocytes are highly expressed in 3TF-piHeps, while fibroblastic markers are reduced. We envision piHeps as useful cell sources for future studies on drug metabolism and toxicity as well as in vitro models for investigation of pig-to-human infectious diseases.
    • Hepatocyte-specific suppression of microRNA-221-3p mitigates liver fibrosis.

      Tsay, Hsin-Chieh; Yuan, Qinggong; Balakrishnan, Asha; Kaiser, Marina; Möbus, Selina; Kozdrowska, Emilia; Farid, Marwa; Tegtmeyer, Pia-Katharina; Borst, Katharina; Vondran, Florian W R; et al. (Elsevier, 2018-12-22)
      Fibrosis, a cardinal feature of a dysfunctional liver, significantly contributes to the ever-increasing mortality due to end-stage chronic liver diseases. The crosstalk between hepatocytes and hepatic stellate cells (HSCs) plays a key role in the progression of fibrosis. Although ample efforts have been devoted to elucidate the functions of HSCs during liver fibrosis, the regulatory functions of hepatocytes remain elusive. Using an unbiased functional microRNA (miRNA) screening, we investigated the ability of hepatocytes to regulate fibrosis by fine-tuning gene expression via miRNA modulation. The in vivo functional analyses were performed by inhibiting miRNA in hepatocytes using adeno-associated virus in carbon-tetrachloride- and 3,5-di-diethoxycarbonyl-1,4-dihydrocollidine-induced liver fibrosis. Blocking miRNA-221-3p function in hepatocytes during chronic liver injury facilitated recovery of the liver and faster resolution of the deposited extracellular matrix. Furthermore, we demonstrate that reduced secretion of C-C motif chemokine ligand 2, as a result of post-transcriptional regulation of GNAI2 (G protein alpha inhibiting activity polypeptide 2) by miRNA-221-3p, mitigates liver fibrosis. Collectively, miRNA modulation in hepatocytes, an easy-to-target cell type in the liver, may serve as a potential therapeutic approach for liver fibrosis.