Generation of high quality of hepatocyte-like cells from induced pluripotent stem cells with Parp1 but lacking c-Myc.

Induced pluripotent stem cells (iPSCs) have a great potential for application in patient-specific therapy. The reprogramming method that does not involve c-Myc reduces tumorigenic risk, but also largely reduces the efficiency of generation of iPSCs, especially for those reprogrammed from damaged cells. Poly(ADP-ribose) polymerase 1 (Parp1) catalyzes a reaction of poly(ADP-ribosylation) and has been reported to enhance cell reprogramming. Using Oct-4/Sox2/Klf4/Parp1 (OSKP) reprogramming method, reprogramming factors plus Parp1 were capable of generation of iPSCs from adult fibroblasts and further toward to differentiate from iPSCs status into hepatocyte-like cells. Our results showed that Oct-4/Sox2/Klf4/Parp1 (OSKP)-derived iPSC exhibited regular pluripotent properties, long-term passages and more stable cellular-divided period. These OSKP-derived iPSCs can effectively differentiate into hepatocyte-like cells (OSKP-iPSC-Heps), and present high mRNA levels of Sox17, HNF3b, and HNF4a in OSKP-iPSC-Heps. The mature hepatic functions, including CYP3A4, LDL uptake, glycogen synthesis and urea secretion were analyzed and well detected in OSKP-iPSC-Heps on day 14 post-differentiation. In conclusion, we demonstrated that Parp1 promoted reprogramming process to generate the high quality of iPSCs, which could be used as a high quality source of hepatocytes.

Huang CS ，Lin HC ，Lu KH ，Wu WW ，Yang YC ，Yang YP ，Chiang CH ，Hsieh JH ，Chang YL ，Lee SD ... -  《-》

Reprogramming induced pluripotent stem cells in the absence of c-Myc for differentiation into hepatocyte-like cells.

Induced pluripotent stem cells (iPSCs) with four reprogramming factors (Oct-4/Sox2/Klf-4/c-Myc) have been shown to differentiate into hepatic lineages. However, it was unclear whether obviation of the c-Myc oncogene in iPSCs affected hepatic differentiation or inhibited in vivo tumor formation. In this study, we demonstrated that iPSCs without c-Myc had the capacity to differentiate into hepatocyte-like cells (iPSC-Heps) with biological functions. As detected using planar-radionuclide imaging and Hoechst labeling assays, these iPSCs and iPSC-Heps tended to mobilize to the injured liver area in thioacetamide (TAA)-treated mice. Intravenous transplantation of both iPSCs and iPSC-Heps but not mouse embryonic fibroblasts (MEFs) reduced the hepatic necrotic area, improved liver functions, and rescued TAA-treated mice from lethal acute hepatic failure (AHF). In addition, microarray-based bioinformatics and quantitative RT-PCR showed high expression of antioxidant genes in iPSCs and iPSC-Heps compared to MEFs. In vivo and in vitro studies of NAC pretreatment confirmed that iPSCs and iPSC-Heps potentially suppressed ROS production and activated antioxidant enzymes in TAA-injured livers. Six months after transplantation in TAA-treated mice, tumor formation was not seen in non-c-Myc iPSC grafts. Therefore, reprogramming adult somatic cells without c-Myc may prevent oxidative stress-induced damage and provide a safer alternative for hepatic regeneration in AHF.

Li HY ，Chien Y ，Chen YJ ，Chen SF ，Chang YL ，Chiang CH ，Jeng SY ，Chang CM ，Wang ML ，Chen LK ，Hung SI ，Huo TI ，Lee SD ，Chiou SH ... -  《-》

Poly(ADP-ribose) polymerase 1 regulates nuclear reprogramming and promotes iPSC generation without c-Myc.

Chiou SH ，Jiang BH ，Yu YL ，Chou SJ ，Tsai PH ，Chang WC ，Chen LK ，Chen LH ，Chien Y ，Chiou GY ... -  《-》

Improvement of non-alcoholic steatohepatitis by hepatocyte-like cells generated from iPSCs with Oct4/Sox2/Klf4/Parp1.

Chien Y ，Huang CS ，Lin HC ，Lu KH ，Tsai PH ，Lai YH ，Chen KH ，Lee SD ，Huang YH ，Wang CY ... -  《Oncotarget》

Artd1/Parp1 regulates reprogramming by transcriptional regulation of Fgf4 via Sox2 ADP-ribosylation.

The recently established reprogramming of somatic cells into induced pluripotent stem cells (iPSCs) by Takahashi and Yamanaka represents a valuable tool for future therapeutic applications. To date, the mechanisms underlying this process are still largely unknown. In particular, the mechanisms how the Yamanaka factors (Oct4, Sox2, Klf4, and c-Myc) directly drive reprogramming and which additional components are involved are still not yet understood. In this study, we aimed at analyzing the role of ADP-ribosyltransferase diphtheria toxin-like one (Artd1; formerly called poly(ADP-ribose) polymerase 1 [Parp1]) during reprogramming. We found that poly(ADP-ribosylation) (PARylation) of the reprogramming factor Sox2 by Artd1 plays an important role during the first days upon transduction with the reprogramming factors. A process that happens before Artd1 in conjunction with 10-11 translocation-2 (Tet2) mediates the histone modifications necessary for the establishment of an activated chromatin state at pluripotency loci (e.g., Nanog and Essrb) [Nature 2012;488:652-655]. Wild-type (WT) fibroblasts treated with an Artd1 inhibitor as well as fibroblasts deficient for Artd1 (Artd1-/-) show strongly decreased reprogramming capacity. Our data indicate that Artd1-mediated PARylation of Sox2 favors its binding to the fibroblast growth factor 4 (Fgf4) enhancer, thereby activating Fgf4 expression. The importance of Fgf4 during the first 4 days upon initiation of reprogramming was also highlighted by the observation that exogenous addition of Fgf4 was sufficient to restore the reprogramming capacity of Artd1-/- fibroblast to WT levels. In conclusion, our data clearly show that the interaction between Artd1 and Sox2 is crucial for the first steps of the reprogramming process and that early expression of Fgf4 (day 2 to day 4) is an essential component for the successful generation of iPSCs.

Weber FA ，Bartolomei G ，Hottiger MO ，Cinelli P ... -  《-》