Direct Reprogramming of Human Fibroblasts to Functional and Expandable Hepatocytes

Huang, Pengyu; Zhang, Ludi; Gao, Yimeng; He, Zhiying; Yao, Dan; Wu, Zhitao; Cen, Jin; Chen, Xiaotao; Liu, Changcheng; Hu, Yiping; Lai, Dongmei; Hu, Zhen-lei; Chen, Li; Zhang, Ying; Cheng, Xin; Ma, Xiaojun; Pan, Guoyu; Wang, Xin; Hui, Lijian

doi:10.1016/j.stem.2014.01.003

Cited by 464 publications

(437 citation statements)

References 47 publications

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“…The technology may be an alternative to iPSCs, but some potential outcomes must be addressed before translating it to the clinic. These may stem from the use of both oncogenes for producing certain cell types (9,12,27,28) and a viral system for integrating exogenous reprogramming factors into the somatic cell genome (9 -11, 28 -40). For example, insertional mutagenesis may occur and lead to the continuous expression of exogenous reprogramming factors in directly converted cells, potentially affecting cellular functionality (41).…”

Section: Discussionmentioning

confidence: 99%

Generation of Integration-free Induced Neural Stem Cells from Mouse Fibroblasts

Kim

Kwak³

et al. 2016

Journal of Biological Chemistry

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The viral vector-mediated overexpression of the defined transcription factors, Brn4/Pou3f4, Sox2, Klf4, and c-Myc (BSKM), could induce the direct conversion of somatic fibroblasts into induced neural stem cells (iNSCs). However, viral vectors may be randomly integrated into the host genome thereby increasing the risk for undesired genotoxicity, mutagenesis, and tumor formation. Here we describe the generation of integration-free iNSCs from mouse fibroblasts by non-viral episomal vectors containing BSKM. The episomal vector-derived iNSCs (eiNSCs) closely resemble control NSCs, and iNSCs generated by retrovirus (r-iNSCs) in morphology, gene expression profile, epigenetic status, and self-renewal capacity. The e-iNSCs are functionally mature, as they could differentiate into all the neuronal cell types both in vitro and in vivo. Our study provides a novel concept for generating functional iNSCs using a non-viral, non-integrating, plasmid-based system that could facilitate their biomedical applicability. Neural stem cells (NSCs),3 somatic stem cells of the brain and spinal cord, could differentiate into three major cell types (neurons, astrocytes, and oligodendrocytes) in the central nervous system (CNS) in response to relevant signaling pathways (1). A number of in vitro transplantation studies with disease animal models have demonstrated that the engrafted NSCs can functionally rescue disease-related phenotypes, proving their therapeutic potential (2-5). Thus, NSCs have long been considered as a potential source for replacing damaged cells and tissues often found in various neurodegenerative diseases (2-5). However, major concerns associated with these cells may preclude expediting advances into their therapeutic application. First, the accessibility of NSCs is largely restricted in vitro, due to their limited origins. Second, the autologous cell transplantation is not feasible using NSCs from their in vivo origins, and furthermore, allogeneic transplantation of NSCs may raise the potential for immune rejection. Finally, with current culture conditions, it is technically challenging to homogeneously maintain human NSCs in vitro (6, 7). Thus, NSC-like cells generated from easily accessible patient somatic cell types such as fibroblasts and blood cells could serve as an autologous source for therapeutic applications, thereby overcoming current obstacles to NSC-mediated translation research.We and others have demonstrated the direct conversion of somatic fibroblasts into self-renewing and multipotent induced neural stem cells (iNSCs) or induced neural progenitor cells (iNPCs) by the forced expression of different sets of transcription factors (8 -12). Recently, Thier et al. (12) have shown that the restricted expression of Oct4 by a tetracycline-dependent lentiviral vector, together with retrovirus-mediated overexpression of Sox2, Klf4, and c-Myc, could elicit the conversion of fibroblasts into iNSCs. Simultaneously, we have generated multipotent and self-renewing iNSCs from mouse fibroblasts by retrovirus-mediated ...

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Section: Discussionmentioning

confidence: 99%

Generation of Integration-free Induced Neural Stem Cells from Mouse Fibroblasts

Kim

Kwak³

et al. 2016

Journal of Biological Chemistry

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“…By contrast, direct reprogramming of mouse and human fibroblasts into hepatocytes was successfully demonstrated with mostly overlapping combinations of three transcription factors. For mouse cells, the factor combination Hnf4a, Foxa1, Foxa2/Foxa3 [43] or Gata4, Hnf1a, Foxa3 [44] showed similar results and the combination FOXA3, HNF1A, HNF4A was effective in human cells although the maturation stage of induced hepatic cells may not be equivalent [45]. Of note, another study by Du et al claimed that a combination of HNF1A, HNF4A and HNF6 together with the factors ATF5, PROX1 and CEBPA was required to generate more mature hepatocytes [46].…”

Section: Generation Of Human-induced Neuronal Cellsmentioning

confidence: 95%

Direct somatic lineage conversion

Tanabe¹,

Haag²,

Wernig³

2015

Phil. Trans. R. Soc. B

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The predominant view of embryonic development and cell differentiation has been that rigid and even irreversible epigenetic marks are laid down along the path of cell specialization ensuring the proper silencing of unrelated lineage programmes. This model made the prediction that specialized cell types are stable and cannot be redirected into other lineages. Accordingly, early attempts to change the identity of somatic cells had little success and was limited to conversions between closely related cell types. Nuclear transplantation experiments demonstrated, however, that specialized cells even from adult mammals can be reprogrammed into a totipotent state. The discovery that a small combination of transcription factors can reprogramme cells to pluripotency without the need of oocytes further supported the view that these epigenetic barriers can be overcome much easier than assumed, but the extent of this flexibility was still unclear. When we showed that a differentiated mesodermal cell can be directly converted to a differentiated ectodermal cell without a pluripotent intermediate, it was suggested that in principle any cell type could be converted into any other cell type. Indeed, the work of several groups in recent years has provided many more examples of direct somatic lineage conversions. Today, the question is not anymore whether a specific cell type can be generated by direct reprogramming but how it can be induced.

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“…Recently, researchers used such liver specific transcription factors for generation of hepatocyte cells from skin fibroblast cells in vitro. [8][9][10][11][12] The ultimate aim of generation of hepatocytes from skin cells to treat liver diseases. If we know the transcription factors and small molecules which have potential to convert hepatocyte from fibroblast, why not to explore transcription factors and small molecules in vivo directly to repair or regenerating the tissue or organs.…”

Section: Commentsmentioning

confidence: 99%