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Rombaut M, Boeckmans J, Rodrigues RM, van Grunsven LA, Vanhaecke T, De Kock J. Direct reprogramming of somatic cells into induced hepatocytes: Cracking the Enigma code. J Hepatol 2021; 75:690-705. [PMID: 33989701 DOI: 10.1016/j.jhep.2021.04.048] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2021] [Revised: 04/29/2021] [Accepted: 04/30/2021] [Indexed: 01/10/2023]
Abstract
There is an unmet need for functional primary human hepatocytes to support the pharmaceutical and (bio)medical demand. The unique discovery, a decade ago, that somatic cells can be drawn out of their apparent biological lockdown to reacquire a pluripotent state has revealed a completely new avenue of possibilities for generating surrogate human hepatocytes. Since then, the number of papers reporting the direct conversion of somatic cells into induced hepatocytes (iHeps) has burgeoned. A hepatic cell fate can be established via the ectopic expression of native liver-enriched transcription factors in somatic cells, thereby bypassing the need for an intermediate (pluripotent) stem cell state. That said, understanding and eventually controlling the processes that give rise to functional iHeps remains challenging. In this review, we provide an overview of the state-of-the-art reprogramming cocktails and techniques, as well as their corresponding conversion efficiencies. Special attention is paid to the role of liver-enriched transcription factors as hepatogenic reprogramming tools and small molecules as facilitators of hepatic transdifferentiation. To conclude, we formulate recommendations to optimise, standardise and enrich the in vitro production of iHeps to reach clinical standards, and propose minimal criteria for their characterisation.
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Affiliation(s)
- Matthias Rombaut
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
| | - Joost Boeckmans
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
| | - Robim M Rodrigues
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
| | - Leo A van Grunsven
- Liver Cell Biology Research Group, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
| | - Tamara Vanhaecke
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium
| | - Joery De Kock
- Department of In Vitro Toxicology and Dermato-Cosmetology, Faculty of Medicine and Pharmacy, Vrije Universiteit Brussel, Laarbeeklaan 103, B-1090 Brussels, Belgium.
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Phenotype instability of hepatocyte-like cells produced by direct reprogramming of mesenchymal stromal cells. Stem Cell Res Ther 2020; 11:154. [PMID: 32276654 PMCID: PMC7323614 DOI: 10.1186/s13287-020-01665-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2020] [Revised: 03/14/2020] [Accepted: 03/27/2020] [Indexed: 12/24/2022] Open
Abstract
BACKGROUND Hepatocyte-like cells (iHEPs) generated by transcription factor-mediated direct reprogramming of somatic cells have been studied as potential cell sources for the development of novel therapies targeting liver diseases. The mechanisms involved in direct reprogramming, stability after long-term in vitro expansion, and safety profile of reprogrammed cells in different experimental models, however, still require further investigation. METHODS iHEPs were generated by forced expression of Foxa2/Hnf4a in mouse mesenchymal stromal cells and characterized their phenotype stability by in vitro and in vivo analyses. RESULTS The iHEPs expressed mixed hepatocyte and liver progenitor cell markers, were highly proliferative, and presented metabolic activities in functional assays. A progressive loss of hepatic phenotype, however, was observed after several passages, leading to an increase in alpha-SMA+ fibroblast-like cells, which could be distinguished and sorted from iHEPs by differential mitochondrial content. The resulting purified iHEPs proliferated, maintained liver progenitor cell markers, and, upon stimulation with lineage maturation media, increased expression of either biliary or hepatocyte markers. In vivo functionality was assessed in independent pre-clinical mouse models. Minimal engraftment was observed following transplantation in mice with acute acetaminophen-induced liver injury. In contrast, upon transplantation in a transgenic mouse model presenting host hepatocyte senescence, widespread engraftment and uncontrolled proliferation of iHEPs was observed, forming islands of epithelial-like cells, adipocyte-like cells, or cells presenting both morphologies. CONCLUSION The results have significant implications for cell reprogramming, suggesting that iHEPs generated by Foxa2/Hnf4a expression have an unstable phenotype and depend on transgene expression for maintenance of hepatocyte-like characteristics, showing a tendency to return to the mesenchymal phenotype of origin and a compromised safety profile.
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Grath A, Dai G. Direct cell reprogramming for tissue engineering and regenerative medicine. J Biol Eng 2019; 13:14. [PMID: 30805026 PMCID: PMC6373087 DOI: 10.1186/s13036-019-0144-9] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2018] [Accepted: 01/27/2019] [Indexed: 02/06/2023] Open
Abstract
Direct cell reprogramming, also called transdifferentiation, allows for the reprogramming of one somatic cell type directly into another, without the need to transition through an induced pluripotent state. Thus, it is an attractive approach to develop novel tissue engineering applications to treat diseases and injuries where there is a shortage of proliferating cells for tissue repair. In certain tissue damage, terminally differentiated somatic cells lose their ability to proliferate, as a result, damaged tissues cannot heal by themselves. Examples of these scenarios include myocardial infarctions, neurodegenerative diseases, and cartilage injuries. Transdifferentiation is capable of reprogramming cells that are abundant in the body into desired cell phenotypes that are able to restore tissue function in damaged areas. Therefore, direct cell reprogramming is a promising direction in the cell and tissue engineering and regenerative medicine fields. In recent years, several methods for transdifferentiation have been developed, ranging from the overexpression of transcription factors via viral vectors, to small molecules, to clustered regularly interspaced short palindromic repeats (CRISPR) and its associated protein (Cas9) for both genetic and epigenetic reprogramming. Overexpressing transcription factors by use of a lentivirus is currently the most prevalent technique, however it lacks high reprogramming efficiencies and can pose problems when transitioning to human subjects and clinical trials. CRISPR/Cas9, fused with proteins that modulate transcription, has been shown to improve efficiencies greatly. Transdifferentiation has successfully generated many cell phenotypes, including endothelial cells, skeletal myocytes, neuronal cells, and more. These cells have been shown to emulate mature adult cells such that they are able to mimic major functions, and some are capable of promoting regeneration of damaged tissue in vivo. While transdifferentiated cells have not yet seen clinical use, they have had promise in mice models, showing success in treating liver disease and several brain-related diseases, while also being utilized as a cell source for tissue engineered vascular grafts to treat damaged blood vessels. Recently, localized transdifferentiated cells have been generated in situ, allowing for treatments without invasive surgeries and more complete transdifferentiation. In this review, we summarized the recent development in various cell reprogramming techniques, their applications in converting various somatic cells, their uses in tissue regeneration, and the challenges of transitioning to a clinical setting, accompanied with potential solutions.
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Affiliation(s)
- Alexander Grath
- Department of Bioengineering, Northeastern University, Lake Hall 214A, 360 Huntington Avenue, Boston, MA 02115 USA
| | - Guohao Dai
- Department of Bioengineering, Northeastern University, Lake Hall 214A, 360 Huntington Avenue, Boston, MA 02115 USA
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Direct Cardiac Reprogramming: A Novel Approach for Heart Regeneration. Int J Mol Sci 2018; 19:ijms19092629. [PMID: 30189626 PMCID: PMC6165160 DOI: 10.3390/ijms19092629] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2018] [Revised: 09/01/2018] [Accepted: 09/01/2018] [Indexed: 12/12/2022] Open
Abstract
Cardiac diseases are among the most common causes of death globally. Cardiac muscle has limited proliferative capacity, and regenerative therapies are highly in demand as a new treatment strategy. Although pluripotent reprogramming has been developed, it has obstacles, such as a potential risk of tumor formation, poor survival of the transplanted cells, and high cost. We previously reported that fibroblasts can be directly reprogrammed to cardiomyocytes by overexpressing a combination of three cardiac-specific transcription factors (Gata4, Mef2c, Tbx5 (together, GMT)). We and other groups have promoted cardiac reprogramming by the addition of certain miRNAs, cytokines, and epigenetic factors, and unraveled new molecular mechanisms of cardiac reprogramming. More recently, we discovered that Sendai virus (SeV) vector expressing GMT could efficiently and rapidly reprogram fibroblasts into integration-free cardiomyocytes in vitro via robust transgene expression. Gene delivery of SeV-GMT also improves cardiac function and reduces fibrosis after myocardial infarction in mice. Through direct cardiac reprogramming, new cardiomyocytes can be generated and scar tissue reduced to restore cardiac function, and, thus, direct cardiac reprogramming may serve as a powerful strategy for cardiac regeneration. Here, we provide an overview of the previous reports and current challenges in this field.
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Cho YD, Yoon S, Kang K, Kim Y, Lee SB, Seo D, Ryu K, Jeong J, Choi D. Simple Maturation of Direct-Converted Hepatocytes Derived from Fibroblasts. Tissue Eng Regen Med 2017; 14:579-586. [PMID: 30603511 PMCID: PMC6171619 DOI: 10.1007/s13770-017-0064-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2017] [Revised: 06/05/2017] [Accepted: 06/08/2017] [Indexed: 12/25/2022] Open
Abstract
Target cells differentiation techniques from stem cells are developed rapidly. Recently, direct conversion techniques are introduced in various categories. Unlike pluripotent stem cells, this technique enables direct differentiation into the other cell types such as neurons, cardiomyocytes, insulin-producing cells, and hepatocytes without going through the pluripotent stage. However, the function of these converted cells reserve an immature phenotype. Therefore, we modified the culture conditions of mouse direct converted hepatocytes (miHeps) to mature fetal characteristics, such as higher AFP and lower albumin (ALB) expression than primary hepatocytes. First, we generate miHeps from mouse embryonic fibroblasts (MEFs) with two transcription factors HNF4α and Foxa3. These cells indicate typical epithelial morphology and express hepatic proteins. To mature hepatic function, DMSO is treated during culture time for more than 7 days. After maturation, miHeps showed features of maturation such as exhibiting typical hepatocyte-like morphology, increased up-regulated ALB and CYP enzyme gene expression, down-regulated AFP expressions, and acquired hepatic function over time. Thus, our data provides a simple method to mature direct converted hepatocytes functionally and these cells enable them to move closer to generating functional hepatocytes.
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Affiliation(s)
- Young-duck Cho
- Department of Emergency Medicine, Korea University Guro Hospital, Seoul, 02841 Korea
| | - Sangtae Yoon
- HY Indang Center of Regenerative Medicine and Stem Cell Research, Hanyang University College of Medicine, Seoul, 04763 Korea
- Department of Surgery, Hanyang University College of Medicine, Seoul, 04763 Korea
| | - Kyojin Kang
- HY Indang Center of Regenerative Medicine and Stem Cell Research, Hanyang University College of Medicine, Seoul, 04763 Korea
- Department of Surgery, Hanyang University College of Medicine, Seoul, 04763 Korea
| | - Yohan Kim
- HY Indang Center of Regenerative Medicine and Stem Cell Research, Hanyang University College of Medicine, Seoul, 04763 Korea
- Department of Surgery, Hanyang University College of Medicine, Seoul, 04763 Korea
| | - Seung Bum Lee
- Laboratory of Radiation Exposure and Therapeutics, National Radiation Emergency Medical Center, Korea Institute of Radiological and Medical Science, Seoul, 01812 Korea
| | - Daekwan Seo
- Bioinformatics Department, Macrogen Corp, Rockville, MD 20850 USA
| | - Kiyoung Ryu
- Department of Obstetrics and Gynecology, Hanyang University College of Medicine, Seoul, 04763 Korea
| | - Jaemin Jeong
- HY Indang Center of Regenerative Medicine and Stem Cell Research, Hanyang University College of Medicine, Seoul, 04763 Korea
- Department of Surgery, Hanyang University College of Medicine, Seoul, 04763 Korea
| | - Dongho Choi
- HY Indang Center of Regenerative Medicine and Stem Cell Research, Hanyang University College of Medicine, Seoul, 04763 Korea
- Department of Surgery, Hanyang University College of Medicine, Seoul, 04763 Korea
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Zakikhan K, Pournasr B, Vosough M, Nassiri-Asl M. In Vitro Generated Hepatocyte-Like Cells: A Novel Tool in Regenerative Medicine and Drug Discovery. CELL JOURNAL 2017; 19:204-217. [PMID: 28670513 PMCID: PMC5412779 DOI: 10.22074/cellj.2016.4362] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/15/2016] [Accepted: 09/05/2016] [Indexed: 12/19/2022]
Abstract
Hepatocyte-like cells (HLCs) are generated from either various human pluripotent stem
cells (hPSCs) including induced pluripotent stem cells (iPSCs) and embryonic stem cells
(ESCs), or direct cell conversion, mesenchymal stem cells as well as other stem cells like
gestational tissues. They provide potential cell sources for biomedical applications. Liver
transplantation is the gold standard treatment for the patients with end stage liver disease,
but there are many obstacles limiting this process, like insufficient number of donated
healthy livers. Meanwhile, the number of patients receiving a liver organ transplant for
a better life is increasing. In this regard, HLCs may provide an adequate cell source to
overcome these shortages. New molecular engineering approaches such as CRISPR/
Cas system applying in iPSCs technology provide the basic principles of gene correction
for monogenic inherited metabolic liver diseases, as another application of HLCs. It has
been shown that HLCs could replace primary human hepatocytes in drug discovery and
hepatotoxicity tests. However, generation of fully functional HLCs is still a big challenge;
several research groups have been trying to improve current differentiation protocols to
achieve better HLCs according to morphology and function of cells. Large-scale generation
of functional HLCs in bioreactors could make a new opportunity in producing enough
hepatocytes for treating end-stage liver patients as well as other biomedical applications
such as drug studies. In this review, regarding the biomedical value of HLCs, we focus
on the current and efficient approaches for generating hepatocyte-like cells in vitro and
discuss about their applications in regenerative medicine and drug discovery.
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Affiliation(s)
- Kobra Zakikhan
- Cellular and Molecular Research Center, Department of Molecular Medicine, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran
| | - Behshad Pournasr
- Department of Stem Cells and Developmental Biology, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Massoud Vosough
- Department of Regenerative Biomedicine, Cell Science Research Center, Royan Institute for Stem Cell Biology and Technology, ACECR, Tehran, Iran
| | - Marjan Nassiri-Asl
- Cellular and Molecular Research Center, Department of Molecular Medicine, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran.,Cellular and Molecular Research Center, Department of Pharmacology, School of Medicine, Qazvin University of Medical Sciences, Qazvin, Iran
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Gérard C, Tys J, Lemaigre FP. Gene regulatory networks in differentiation and direct reprogramming of hepatic cells. Semin Cell Dev Biol 2016; 66:43-50. [PMID: 27979774 DOI: 10.1016/j.semcdb.2016.12.003] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2016] [Accepted: 12/07/2016] [Indexed: 12/14/2022]
Abstract
Liver development proceeds by sequential steps during which gene regulatory networks (GRNs) determine differentiation and maturation of hepatic cells. Characterizing the architecture and dynamics of these networks is essential for understanding how cell fate decisions are made during development, and for recapitulating these processes during in vitro production of liver cells for toxicology studies, disease modelling and regenerative therapy. Here we review the GRNs that control key steps of liver development and lead to differentiation of hepatocytes and cholangiocytes in mammals. We focus on GRNs determining cell fate decisions and analyse subcircuitry motifs that may confer specific dynamic properties to the networks. Finally, we put our analysis in the perspective of recent attempts to directly reprogram cells to hepatocytes by forced expression of transcription factors.
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Affiliation(s)
- Claude Gérard
- Université catholique de Louvain, de Duve Institute, Avenue Hippocrate 75, 1200 Brussels, Belgium.
| | - Janne Tys
- Université catholique de Louvain, de Duve Institute, Avenue Hippocrate 75, 1200 Brussels, Belgium.
| | - Frédéric P Lemaigre
- Université catholique de Louvain, de Duve Institute, Avenue Hippocrate 75, 1200 Brussels, Belgium.
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Vasconcellos R, Alvarenga ÉC, Parreira RC, Lima SS, Resende RR. Exploring the cell signalling in hepatocyte differentiation. Cell Signal 2016; 28:1773-88. [DOI: 10.1016/j.cellsig.2016.08.011] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2016] [Revised: 08/18/2016] [Accepted: 08/18/2016] [Indexed: 02/08/2023]
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