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Keepers B, Liu J, Qian L. What's in a cardiomyocyte - And how do we make one through reprogramming? BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2019; 1867:118464. [PMID: 30922868 DOI: 10.1016/j.bbamcr.2019.03.011] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 03/10/2019] [Accepted: 03/21/2019] [Indexed: 12/19/2022]
Abstract
Substantial progress is being made in the field cardiac reprogramming, and those in the field are hopeful that the technology will be formulated for therapeutic use. Beyond the excitement around generating a revolutionary new approach for treating ischemic heart diseases, cardiac reprogramming has delivered provocative findings that challenge common notions of cell fate and cell identity. Have we really made de novo cardiomyocytes? To answer this question, the essential characteristics of this unique and important cell type must first be defined. In this review, we walk through the history of scientific inquiry into cardiomyocytes, and then we examine the core features of cardiomyocytes as detailed in modern definitions. Informed by this, we turn to cardiac reprogramming to analyze the various screening approaches and ultimate factor combinations used in each study. We follow this with a dissection of the evidence used to support the authors' claims of successfully creating cardiomyocytes, and we end by discussing what is known about the molecular mechanisms of cardiac reprogramming. Through this analysis, we find interesting differences between the study designs and their results, but it becomes clear that the field at large is generating cells that closely match the textbook definition cardiomyocyte. However, the differences noted between the results of each study are largely unexplained, reflecting the need for further research in both cardiac reprogramming and in native cardiomyocyte biology. Knowledge gained from future research will help move the field towards better reprogramming techniques and technologies.
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Affiliation(s)
- Benjamin Keepers
- McAllister Heart Institute, Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Jiandong Liu
- McAllister Heart Institute, Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA
| | - Li Qian
- McAllister Heart Institute, Department of Pathology and Laboratory Medicine, University of North Carolina, Chapel Hill, NC 27599, USA.
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Tian J, Wang R, Hou Q, Li M, Chen L, Deng X, Zhu Z, Zhao Y, He W, Fu X. Optimization and enrichment of induced cardiomyocytes derived from mouse fibroblasts by reprogramming with cardiac transcription factors. Mol Med Rep 2017; 17:3912-3920. [PMID: 29257325 DOI: 10.3892/mmr.2017.8285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2017] [Accepted: 09/29/2017] [Indexed: 11/05/2022] Open
Abstract
Ischemic heart disease within developed countries has been associated with high rates of morbidity and mortality. Cell‑based cardiac repair is an emerging therapy for the treatment of cardiac diseases; however, a limited source of the optimal type of donor cell, such as an autologous cardiomyocyte, restricts clinical application. The novel therapeutic use of induced pluripotent stem cells (iPSCs) may serve as a unique and unlimited source of cardiomyocytes; however, iPSC contamination has been associated with teratoma formation following transplantation. The present study investigated whether cardiomyocytes from mouse fibroblasts may be reprogrammed in vitro with four cardiac transcription factors, including GATA binding protein 4, myocyte‑specific enhancer factor 2C, T‑box transcription factor 5, and heart‑ and neural crest derivatives‑expressed protein 2 (GMTH). Cardiac‑specific markers, including α‑myosin heavy chain (α‑MHC), β‑MHC, atrial natriuretic factor, NK2 homeobox 5 and cardiac troponin T were observed within mouse fibroblasts reprogrammed with GMTH, which was reported to be more effective than GMT. In addition, Percoll density centrifugation enriched a population of ~72.4±5.5% α‑MHC+ induced cardiomyocytes, which retained the expression profile of cardiomyocyte markers and were similar to natural neonatal cardiomyocytes in well‑defined sarcomeric structures. The findings of the present study provided a potential solution to myocardial repair via a cell therapy applying tissue engineering with minimized risks of immune rejection and tumor formation.
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Affiliation(s)
- Jiaxin Tian
- Centre for Medical Device Evaluation, China Food and Drug Administration, Beijing 100044, P.R. China
| | - Rong Wang
- Department of Cardiovascular Surgery, Institute of Cardiac Surgery of PLA, Beijing 100853, P.R. China
| | - Qian Hou
- Institute of Basic Medicine, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Meirong Li
- Institute of Basic Medicine, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Li Chen
- Institute of Basic Medicine, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Xiangdong Deng
- Institute of Basic Medicine, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Ziying Zhu
- Institute of Basic Medicine, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Yali Zhao
- Institute of Basic Medicine, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Wenjun He
- Institute of Basic Medicine, Chinese PLA General Hospital, Beijing 100853, P.R. China
| | - Xiaobing Fu
- Institute of Basic Medicine, Chinese PLA General Hospital, Beijing 100853, P.R. China
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Bektik E, Dennis A, Prasanna P, Madabhushi A, Fu JD. Single cell qPCR reveals that additional HAND2 and microRNA-1 facilitate the early reprogramming progress of seven-factor-induced human myocytes. PLoS One 2017; 12:e0183000. [PMID: 28796841 PMCID: PMC5552090 DOI: 10.1371/journal.pone.0183000] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Accepted: 07/27/2017] [Indexed: 01/04/2023] Open
Abstract
The direct reprogramming of cardiac fibroblasts into induced cardiomyocyte (CM)-like cells (iCMs) holds great promise in restoring heart function. We previously found that human fibroblasts could be reprogrammed toward CM-like cells by 7 reprogramming factors; however, iCM reprogramming in human fibroblasts is both more difficult and more time-intensive than that in mouse cells. In this study, we investigated if additional reprogramming factors could quantitatively and/or qualitatively improve 7-factor-mediated human iCM reprogramming by single-cell quantitative PCR. We first validated 46 pairs of TaqMan® primers/probes that had sufficient efficiency and sensitivity to detect the significant difference of gene expression between individual H9 human embryonic stem cell (ESC)-differentiated CMs (H9CMs) and human fibroblasts. The expression profile of these 46 genes revealed an improved reprogramming in 12-week iCMs compared to 4-week iCMs reprogrammed by 7 factors, indicating a prolonged stochastic phase during human iCM reprogramming. Although none of additional one reprogramming factor yielded a greater number of iCMs, our single-cell qPCR revealed that additional HAND2 or microRNA-1 could facilitate the silencing of fibroblast genes and yield a better degree of reprogramming in more reprogrammed iCMs. Noticeably, the more HAND2 expressed, the higher-level were cardiac genes activated in 7Fs+HAND2-reprogrammed iCMs. In conclusion, HAND2 and microRNA-1 could help 7 factors to facilitate the early progress of iCM-reprogramming from human fibroblasts. Our study provides valuable information to further optimize a method of direct iCM-reprogramming in human cells.
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Affiliation(s)
- Emre Bektik
- Department of Medicine, Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, United States of America
- School of Integrative and Global Majors, University of Tsukuba, Tsukuba, Japan
| | - Adrienne Dennis
- Department of Medicine, Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Prateek Prasanna
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Anant Madabhushi
- Department of Biomedical Engineering, Case Western Reserve University, Cleveland, Ohio, United States of America
| | - Ji-Dong Fu
- Department of Medicine, Heart and Vascular Research Center, MetroHealth Campus, Case Western Reserve University, Cleveland, Ohio, United States of America
- * E-mail:
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Doppler SA, Deutsch MA, Lange R, Krane M. Direct Reprogramming-The Future of Cardiac Regeneration? Int J Mol Sci 2015; 16:17368-93. [PMID: 26230692 PMCID: PMC4581198 DOI: 10.3390/ijms160817368] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2015] [Revised: 07/17/2015] [Accepted: 07/22/2015] [Indexed: 12/12/2022] Open
Abstract
Today, the only available curative therapy for end stage congestive heart failure (CHF) is heart transplantation. This therapeutic option is strongly limited by declining numbers of available donor hearts and by restricted long-term performance of the transplanted graft. The disastrous prognosis for CHF with its restricted therapeutic options has led scientists to develop different concepts of alternative regenerative treatment strategies including stem cell transplantation or stimulating cell proliferation of different cardiac cell types in situ. However, first clinical trials with overall inconsistent results were not encouraging, particularly in terms of functional outcome. Among other approaches, very promising ongoing pre-clinical research focuses on direct lineage conversion of scar fibroblasts into functional myocardium, termed “direct reprogramming” or “transdifferentiation.” This review seeks to summarize strategies for direct cardiac reprogramming including the application of different sets of transcription factors, microRNAs, and small molecules for an efficient generation of cardiomyogenic cells for regenerative purposes.
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Affiliation(s)
- Stefanie A Doppler
- Division of Experimental Surgery, Department of Cardiovascular Surgery, Deutsches Herzzentrum München, Technische Universität München (TUM), Munich 80636, Germany.
| | - Marcus-André Deutsch
- Division of Experimental Surgery, Department of Cardiovascular Surgery, Deutsches Herzzentrum München, Technische Universität München (TUM), Munich 80636, Germany.
| | - Rüdiger Lange
- Division of Experimental Surgery, Department of Cardiovascular Surgery, Deutsches Herzzentrum München, Technische Universität München (TUM), Munich 80636, Germany.
- DZHK (German Center for Cardiovascular Research)-Partner Site Munich Heart Alliance, Munich 80802, Germany.
| | - Markus Krane
- Division of Experimental Surgery, Department of Cardiovascular Surgery, Deutsches Herzzentrum München, Technische Universität München (TUM), Munich 80636, Germany.
- DZHK (German Center for Cardiovascular Research)-Partner Site Munich Heart Alliance, Munich 80802, Germany.
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Fu JD, Srivastava D. Direct reprogramming of fibroblasts into cardiomyocytes for cardiac regenerative medicine. Circ J 2015; 79:245-54. [PMID: 25744738 DOI: 10.1253/circj.cj-14-1372] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Cardiac fibroblasts play critical roles in maintaining normal cardiac function and in cardiac remodeling during pathological conditions such as myocardial infarction (MI). Adult cardiomyocytes (CMs) have little to no regenerative capacity; damaged CMs in the heart after MI are replaced by cardiac fibroblasts that become activated and transform into myofibroblasts, which preserves the structural integrity. Unfortunately, this process typically causes fibrosis and reduces cardiac function. Directly reprogramming adult cardiac fibroblasts into induced CM-like cells (iCMs) holds great promise for restoring heart function. Direct cardiac reprogramming also provides a new research model to investigate which transcription factors and microRNAs control the molecular network that guides cardiac cell fate. We review the approaches and characterization of in vitro and in vivo reprogrammed iCMs from different laboratories, and outline the future directions needed to translate this new approach into a practical therapy for damaged hearts.
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Affiliation(s)
- Ji-Dong Fu
- Heart and Vascular Research Center, MetroHealth Campus of Case Western Reserve University, Cleveland, OH, USA; Gladstone Institute of Cardiovascular Disease, USA; Roddenberry Center for Stem Cell Biology and Medicine at Gladstone, San Francisco, CA, USA
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Abstract
Heart disease is a major cause of morbidity and mortality worldwide. The low regenerative capacity of adult human hearts has thus far limited the available therapeutic approaches for heart failure. Therefore, new therapies that can regenerate damaged myocardium and improve heart function are urgently needed. Although cell transplantation-based therapies may hold great potential, direct reprogramming of endogenous cardiac fibroblasts, which represent more than half of the cells in the heart, into functional cardiomyocytes in situ may be an alternative strategy by which to regenerate the heart. We and others demonstrated that functional cardiomyocytes can be directly generated from fibroblasts by using several combinations of cardiac-enriched factors in mouse and human. In vivo gene delivery of cardiac reprogramming factors generates new cardiac muscle and improved heart function after myocardial infarction in mouse. This article reviews recent progress in cardiac reprogramming research and discusses the perspectives and challenges of this new technology for future regenerative therapy.
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Affiliation(s)
- Naoto Muraoka
- Department of Clinical and Molecular Cardiovascular Research
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Yi BA, Mummery CL, Chien KR. Direct cardiomyocyte reprogramming: a new direction for cardiovascular regenerative medicine. Cold Spring Harb Perspect Med 2013; 3:a014050. [PMID: 24003244 DOI: 10.1101/cshperspect.a014050] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
The past few years have seen unexpected new developments in direct cardiomyocyte reprogramming. Direct cardiomyocyte reprogramming potentially offers an entirely novel approach to cardiovascular regenerative medicine by converting cardiac fibroblasts into functional cardiomyocytes in situ. There is much to be learned, however, about the mechanisms of direct reprogramming in order that the process can be made more efficient. Early efforts have suggested that this new technology can be technically challenging. Moreover, new methods of inducing heart reprogramming will need to be developed before this approach can be translated to the bedside. Despite this, direct cardiomyocyte reprogramming may lead to new therapeutic options for sufferers of heart disease.
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Affiliation(s)
- B Alexander Yi
- Cardiovascular Research Center, Massachusetts General Hospital, Boston, Massachusetts 02114
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Addis RC, Ifkovits JL, Pinto F, Kellam LD, Esteso P, Rentschler S, Christoforou N, Epstein JA, Gearhart JD. Optimization of direct fibroblast reprogramming to cardiomyocytes using calcium activity as a functional measure of success. J Mol Cell Cardiol 2013; 60:97-106. [PMID: 23591016 PMCID: PMC3679282 DOI: 10.1016/j.yjmcc.2013.04.004] [Citation(s) in RCA: 170] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/10/2013] [Revised: 04/03/2013] [Accepted: 04/05/2013] [Indexed: 01/14/2023]
Abstract
Direct conversion of fibroblasts to induced cardiomyocytes (iCMs) has great potential for regenerative medicine. Recent publications have reported significant progress, but the evaluation of reprogramming has relied upon non-functional measures such as flow cytometry for cardiomyocyte markers or GFP expression driven by a cardiomyocyte-specific promoter. The issue is one of practicality: the most stringent measures - electrophysiology to detect cell excitation and the presence of spontaneously contracting myocytes - are not readily quantifiable in the large numbers of cells screened in reprogramming experiments. However, excitation and contraction are linked by a third functional characteristic of cardiomyocytes: the rhythmic oscillation of intracellular calcium levels. We set out to optimize direct conversion of fibroblasts to iCMs with a quantifiable calcium reporter to rapidly assess functional transdifferentiation. We constructed a reporter system in which the calcium indicator GCaMP is driven by the cardiomyocyte-specific Troponin T promoter. Using calcium activity as our primary outcome measure, we compared several published combinations of transcription factors along with novel combinations in mouse embryonic fibroblasts. The most effective combination consisted of Hand2, Nkx2.5, Gata4, Mef2c, and Tbx5 (HNGMT). This combination is >50-fold more efficient than GMT alone and produces iCMs with cardiomyocyte marker expression, robust calcium oscillation, and spontaneous beating that persist for weeks following inactivation of reprogramming factors. HNGMT is also significantly more effective than previously published factor combinations for the transdifferentiation of adult mouse cardiac fibroblasts to iCMs. Quantification of calcium function is a convenient and effective means for the identification and evaluation of cardiomyocytes generated by direct reprogramming. Using this stringent outcome measure, we conclude that HNGMT produces iCMs more efficiently than previously published methods.
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Affiliation(s)
- Russell C. Addis
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Jamie L. Ifkovits
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Filipa Pinto
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Lori D. Kellam
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Paul Esteso
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - Stacey Rentschler
- Department of Internal Medicine, Washington University in St. Louis, St. Louis, MO, USA
| | | | - Jonathan A. Epstein
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
| | - John D. Gearhart
- Institute for Regenerative Medicine and Department of Cell and Developmental Biology, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA
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