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 ... -  《-》

Improvement of carbon tetrachloride-induced acute hepatic failure by transplantation of induced pluripotent stem cells without reprogramming factor c-Myc.

Chang HM ，Liao YW ，Chiang CH ，Chen YJ ，Lai YH ，Chang YL ，Chen HL ，Jeng SY ，Hsieh JH ，Peng CH ，Li HY ，Chien Y ，Chen SY ，Chen LK ，Huo TI ... -  《INTERNATIONAL JOURNAL OF MOLECULAR SCIENCES》

Enhanced antioxidant capacity of dental pulp-derived iPSC-differentiated hepatocytes and liver regeneration by injectable HGF-releasing hydrogel in fulminant hepatic failure.

Chiang CH ，Wu WW ，Li HY ，Chien Y ，Sun CC ，Peng CH ，Lin AT ，Huang CS ，Lai YH ，Chiou SH ，Hung SI ，Chang YL ，Lan YT ，Liu DM ，Chien CS ，Huo TI ，Lee SD ，Wang CY ... -  《-》

Enhanced human somatic cell reprogramming efficiency by fusion of the MYC transactivation domain and OCT4.

The development of human induced pluripotent stem cells (iPSCs) holds great promise for regenerative medicine. However the iPSC induction efficiency is still very low and with lengthy reprogramming process. We utilized the highly potent transactivation domain (TAD) of MYC protein to engineer the human OCT4 fusion proteins. Applying the MYC-TAD-OCT4 fusion proteins in mouse iPSC generation leads to shorter reprogramming dynamics, with earlier activation of pluripotent markers in reprogrammed cells than wild type OCT4 (wt-OCT4). Dramatic enhancement of iPSC colony induction efficiency and shortened reprogramming dynamics were observed when these MYC-TAD-OCT4 fusion proteins were used to reprogram primary human cells. The OCT4 fusion proteins induced human iPSCs are pluripotent. We further show that the MYC Box I (MBI) is dispensable while both MBII and the linking region between MBI/II are essential for the enhanced reprogramming activity of MYC-TAD-OCT4 fusion protein. Consistent with an enhanced transcription activity, the engineered OCT4 significantly stimulated the expression of genes specifically targeted by OCT4-alone, OCT4/SOX2, and OCT4/SOX2/KLF4 during human iPSC induction, compared with the wt-OCT4. The MYC-TAD-OCT4 fusion proteins we generated will be valuable tools for studying the reprogramming mechanisms and for efficient iPSC generation for humans as well as for other species.

Wang L ，Huang D ，Huang C ，Yin Y ，Vali K ，Zhang M ，Tang Y ... -  《-》

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 ... -  《-》