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Reprogramming and transdifferentiation - two key processes for regenerative medicine. Eur J Pharmacol 2020; 882:173202. [PMID: 32562801 DOI: 10.1016/j.ejphar.2020.173202] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2019] [Revised: 04/22/2020] [Accepted: 05/13/2020] [Indexed: 12/11/2022]
Abstract
Regenerative medicine based on transplants obtained from donors or foetal and new-born mesenchymal stem cells, encounter important obstacles such as limited availability of organs, ethical issues and immune rejection. The growing demand for therapeutic methods for patients being treated after serious accidents, severe organ dysfunction and an increasing number of cancer surgeries, exceeds the possibilities of the therapies that are currently available. Reprogramming and transdifferentiation provide powerful bioengineering tools. Both procedures are based on the somatic differentiated cells, which are easily and unlimitedly available, like for example: fibroblasts. During the reprogramming procedure mature cells are converted into pluripotent cells - which are capable to differentiate into almost any kind of desired cells. Transdifferentiation directly converts differentiated cells of one type into another differentiated cells type. Both procedures allow to obtained patient's dedicated cells for therapeutic purpose in regenerative medicine. In combination with biomaterials, it is possible to obtain even whole anatomical structures. Those patient's dedicated structures may serve for them upon serious accidents with massive tissue damage but also upon cancer surgeries as a replacement of damaged organ. Detailed information about reprogramming and transdifferentiation procedures as well as the current state of the art are presented in our review.
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Wang X. Stem cells in tissues, organoids, and cancers. Cell Mol Life Sci 2019; 76:4043-4070. [PMID: 31317205 PMCID: PMC6785598 DOI: 10.1007/s00018-019-03199-x] [Citation(s) in RCA: 37] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2019] [Revised: 05/22/2019] [Accepted: 06/17/2019] [Indexed: 12/13/2022]
Abstract
Stem cells give rise to all cells and build the tissue structures in our body, and heterogeneity and plasticity are the hallmarks of stem cells. Epigenetic modification, which is associated with niche signals, determines stem cell differentiation and somatic cell reprogramming. Stem cells play a critical role in the development of tumors and are capable of generating 3D organoids. Understanding the properties of stem cells will improve our capacity to maintain tissue homeostasis. Dissecting epigenetic regulation could be helpful for achieving efficient cell reprograming and for developing new drugs for cancer treatment. Stem cell-derived organoids open up new avenues for modeling human diseases and for regenerative medicine. Nevertheless, in addition to the achievements in stem cell research, many challenges still need to be overcome for stem cells to have versatile application in clinics.
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Affiliation(s)
- Xusheng Wang
- School of Pharmaceutical Sciences (Shenzhen), Sun Yat-sen University, Guangzhou, 510275, China.
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Londono R, Sun AX, Tuan RS, Lozito TP. TISSUE REPAIR AND EPIMORPHIC REGENERATION: AN OVERVIEW. CURRENT PATHOBIOLOGY REPORTS 2018; 6:61-69. [PMID: 29967714 PMCID: PMC6025457 DOI: 10.1007/s40139-018-0161-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
PURPOSE OF THE REVIEW This manuscript discusses wound healing as a component of epimorphic regeneration and the role of the immune system in this process. RECENT FINDINGS Epimorphic regeneration involves formation of a blastema, a mass of undifferentiated cells capable of giving rise to the regenerated tissues. The apical epithelial cap plays an important role in blastemal formation. SUMMARY True regeneration is rarely observed in mammals. With the exception of transgenic strains, tissue repair in mammals usually leads to non-functional fibrotic tissue formation. In contrast, a number of lower order species including planarians, salamanders, and reptiles, have the ability to overcome the burden of scarring and tissue loss through complex adaptations that allow them to regenerate various anatomic structures through epimorphic regeneration. Blastemal cells have been suggested to originate via various mechanisms including de-differentiation, transdifferentiation, migration of pre-existing adult stem cell niches, and combinations of these.
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Affiliation(s)
- Ricardo Londono
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
| | - Aaron X. Sun
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- School of Medicine, University of Pittsburgh, Pittsburgh, PA, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Rocky S. Tuan
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA, USA
| | - Thomas P. Lozito
- Center for Cellular and Molecular Engineering, Department of Orthopaedic Surgery, University of Pittsburgh School of Medicine, Pittsburgh, PA, USA
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Ghosh S. Human regeneration: An achievable goal or a dream? J Biosci 2016; 41:157-65. [PMID: 26949097 DOI: 10.1007/s12038-016-9589-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
The main objective of regenerative medicine is to replenish cells or tissues or even to restore different body parts that are lost or damaged due to disease, injury and aging. Several avenues have been explored over many decades to address the fascinating problem of regeneration at the cell, tissue and organ levels. Here we discuss some of the primary approaches adopted by researchers in the context of enhancing the regenerating ability of mammals. Natural regeneration can occur in different animal species, and the underlying mechanism is highly relevant to regenerative medicine-based intervention. Significant progress has been achieved in understanding the endogenous regeneration in urodeles and fishes with the hope that they could help to reach our goal of designing future strategies for human regeneration.
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Affiliation(s)
- Sukla Ghosh
- Department of Biophysics, Molecular Biology and Bioinformatics, University of Calcutta, 92, A. P.C. Road, Kolkata 700 009, India,
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El-Badawy A, El-Badri N. Regulators of pluripotency and their implications in regenerative medicine. STEM CELLS AND CLONING-ADVANCES AND APPLICATIONS 2015; 8:67-80. [PMID: 25960670 PMCID: PMC4410894 DOI: 10.2147/sccaa.s80157] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The ultimate goal of regenerative medicine is to replace damaged tissues with new functioning ones. This can potentially be accomplished by stem cell transplantation. While stem cell transplantation for blood diseases has been increasingly successful, widespread application of stem cell therapy in the clinic has shown limited results. Despite successful efforts to refine existing methodologies and to develop better ones for reprogramming, clinical application of stem cell therapy suffers from issues related to the safety of the transplanted cells, as well as the low efficiency of reprogramming technology. Better understanding of the underlying mechanism(s) involved in pluripotency should accelerate the clinical application of stem cell transplantation for regenerative purposes. This review outlines the main decision-making factors involved in pluripotency, focusing on the role of microRNAs, epigenetic modification, signaling pathways, and toll-like receptors. Of special interest is the role of toll-like receptors in pluripotency, where emerging data indicate that the innate immune system plays a vital role in reprogramming. Based on these data, we propose that nongenetic mechanisms for reprogramming provide a novel and perhaps an essential strategy to accelerate application of regenerative medicine in the clinic.
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Affiliation(s)
- Ahmed El-Badawy
- Center of Excellence for Stem Cells and Regenerative Medicine, Zewail City of Science and Technology, Giza, Egypt
| | - Nagwa El-Badri
- Center of Excellence for Stem Cells and Regenerative Medicine, Zewail City of Science and Technology, Giza, Egypt
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Abstract
Tumor suppressors are so named because cancers occur in their absence, but these genes also have important functions in development, metabolism and tissue homeostasis. Here, we discuss known and potential functions of tumor suppressor genes during tissue regeneration, focusing on the evolutionarily conserved tumor suppressors pRb1, p53, Pten and Hippo. We propose that their activity is essential for tissue regeneration. This is in contrast to suggestions that tumor suppression is a trade-off for regenerative capacity. We also hypothesize that certain aspects of tumor suppressor pathways inhibit regenerative processes in mammals, and that transient targeted modification of these pathways could be fruitfully exploited to enhance processes that are important to regenerative medicine.
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Affiliation(s)
- Jason H Pomerantz
- Department of Surgery, Division of Plastic and Reconstructive Surgery, University of California, San Francisco, CA 94143, USA.
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Jopling C, Boue S, Izpisua Belmonte JC. Dedifferentiation, transdifferentiation and reprogramming: three routes to regeneration. Nat Rev Mol Cell Biol 2011; 12:79-89. [PMID: 21252997 DOI: 10.1038/nrm3043] [Citation(s) in RCA: 479] [Impact Index Per Article: 36.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
The ultimate goal of regenerative medicine is to replace lost or damaged cells. This can potentially be accomplished using the processes of dedifferentiation, transdifferentiation or reprogramming. Recent advances have shown that the addition of a group of genes can not only restore pluripotency in a fully differentiated cell state (reprogramming) but can also induce the cell to proliferate (dedifferentiation) or even switch to another cell type (transdifferentiation). Current research aims to understand how these processes work and to eventually harness them for use in regenerative medicine.
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Affiliation(s)
- Chris Jopling
- Center of Regenerative Medicine in Barcelona, Dr. Aiguader, 88, 08003 Barcelona, Spain
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Wolfe AD, Crimmins G, Cameron JA, Henry JJ. Early regeneration genes: Building a molecular profile for shared expression in cornea-lens transdifferentiation and hindlimb regeneration in Xenopus laevis. Dev Dyn 2005; 230:615-29. [PMID: 15254896 DOI: 10.1002/dvdy.20089] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022] Open
Abstract
Recent studies in Xenopus laevis have begun to compare gene expression during regeneration with that of the original development of specific structures (e.g., the hindlimb and lens), while other studies have sought differences in gene expression between regeneration-competent and regeneration-incompetent stages. To determine whether there are any similarities between the regeneration of different structures, we have used a differential screen to seek shared early gene expression between hindlimb regeneration and cornea-lens transdifferentiation in the Xenopus tadpole. We have isolated 13 clones representing genes whose expression is up-regulated within the first few days of both regenerating processes and which are not demonstrably up-regulated in the context of basic wound healing. Furthermore, all of these genes also show prominent late embryonic expression. The expression patterns and putative identities of all 13 genes are presented, and a model is considered that allows us to characterize and profile important changes in gene expression, which might be shared among various regenerating and developmental systems.
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Affiliation(s)
- Adam D Wolfe
- Department of Cell and Structural Biology and College of Medicine, University of Illinois, Urbana, 61801, USA
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Imokawa Y, Simon A, Brockes JP. A critical role for thrombin in vertebrate lens regeneration. Philos Trans R Soc Lond B Biol Sci 2004; 359:765-76. [PMID: 15293804 PMCID: PMC1693368 DOI: 10.1098/rstb.2004.1467] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Lens regeneration in urodele amphibians such as the newt proceeds from the dorsal margin of the iris where pigment epithelial cells (PEC) re-enter the cell cycle and transdifferentiate into lens. A general problem in regeneration research is to understand how the events of tissue injury or removal are coupled to the activation of plasticity in residual differentiated cells or stem cells. Thrombin, a pivotal regulator of the injury response, has been implicated as a regulator of cell cycle re-entry in newt myotubes, and also in newt iris PEC. After removal of the lens, thrombin was activated on the dorsal margin for 5-7 days. Inactivation of thrombin by either of two different inhibitors essentially blocked S-phase re-entry by PEC at this location. The axolotl, a related species which can regenerate its limb but not its lens, can activate thrombin after amputation but not after lens removal. These data support the hypothesis that thrombin is a critical signal linking injury to regeneration, and offer a new perspective on the evolutionary and phylogenetic questions about regeneration.
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Affiliation(s)
- Yutaka Imokawa
- Department of Biochemistry, University College London, Gower Street, London WC1E 6BT, UK
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Tsonis PA, Madhavan M, Call MK, Gainer S, Rice A, Del Rio-Tsonis K. Effects of a CDK inhibitor on lens regeneration. Wound Repair Regen 2004; 12:24-9. [PMID: 14974961 DOI: 10.1111/j.1067-1927.2004.012107.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
Lens regeneration in adult newts is always initiated from the dorsal iris by transdifferentiation of the pigment epithelial cells. One of the most important early events should be the ability of pigment epithelial cells to dedifferentiate and re-enter the cell cycle. As a first step in an attempt to study this event, we have decided to examine the effects of a cyclin-dependent kinase-2 inhibitor on lens regeneration. At the appropriate concentration, this inhibitor completely abolished the ability of pigment epithelial cells to form a new lens, but it did not stop them from dedifferentiating and forming a small lens vesicle. The effects of this inhibitor seem to be mediated by its opposite effects on cell proliferation and apoptosis. The inhibitor significantly reduced cell proliferation and enhanced apoptosis of pigment epithelial cells both in vitro and in vivo and of the regenerating lens in vivo.
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Affiliation(s)
- Panagiotis A Tsonis
- Laboratory of Molecular Biology, Department of Biology, University of Dayton, Dayton, Ohio 45469-2320, USA.
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