Clonality of mouse and human cardiomyogenesis in vivo

• Published in: Proceedings of the National Academy of Sciences - PNAS 2009-10, Vol.106 (40), p.17169-17174
• Main Authors: Hosoda, Toru, D'Amario, Domenico, Cabral-Da-Silva, Mauricio Castro, Zheng, Hanqiao, Padin-Iruegas, M. Elena, Ogorek, Barbara, Ferreira-Martins, João, Yasuzawa-Amano, Saori, Amano, Katsuya, Ide-Iwata, Noriko, Cheng, Wei, Rota, Marcello, Urbanek, Konrad, Kajstura, Jan, Anversa, Piero, Leri, Annarosa
• Format: Article
• Language: English
• Subjects: 3T3 Cells; Animals; Base Sequence; Biological Sciences; Blood cells; cardiomyocytes; Cell Differentiation; Cell Lineage; Cell Proliferation; Cells; Clone Cells - cytology; Clone Cells - metabolism; Cloning; Daughter cells; Endothelial cells; Endothelial Cells - cytology; Endothelial Cells - metabolism; Female; Fibroblasts; Fibroblasts - cytology; Fibroblasts - metabolism; Genetic Vectors - genetics; Genetics; Genomes; Green Fluorescent Proteins - genetics; Green Fluorescent Proteins - metabolism; Heart; Heart attacks; Humans; Immunohistochemistry; Infection; Integration; Lentivirus; Lentivirus - genetics; Mice; Molecular Sequence Data; Multipotent stem cells; Myocardial infarction; Myocardium; Myocardium - cytology; Myocardium - metabolism; Myocytes; Myocytes, Cardiac - cytology; Myocytes, Cardiac - metabolism; Myosin Heavy Chains - genetics; Myosin Heavy Chains - metabolism; Polymerase chain reaction; Progeny; Rats; Rats, Inbred F344; Recombinant Fusion Proteins - genetics; Recombinant Fusion Proteins - metabolism; Reporter gene; Reverse Transcriptase Polymerase Chain Reaction; Rodents; Stem cells; Time Factors
• ISSN: 0027-8424; 1091-6490
• DOI: 10.1073/pnas.0903089106

An analysis of the clonality of cardiac progenitor cells (CPCs) and myocyte turnover in vivo requires genetic tagging of the undifferentiated cells so that the clonal marker of individual mother cells is traced in the specialized progeny. CPC niches in the atria and apex of the mouse heart were infected with a lentivirus carrying EGFP, and the destiny of the tagged cells was determined 1-5 months later. A common integration site was identified in isolated CPCs, cardiomyocytes, endothelial cells (ECs), and fibroblasts, documenting CPC self-renewal and multipotentiality and the clonal origin of the differentiated cell populations. Subsequently, the degree of EGFP-lentiviral infection of CPCs was evaluated 2-4 days after injection, and the number of myocytes expressing the reporter gene was measured 6 months later. A BrdU pulse-chasing protocol was also introduced as an additional assay for the analysis of myocyte turnover. Over a period of 6 months, each EGFP-positive CPC divided approximately eight times generating 230 cardiomyocytes; this value was consistent with the number of newly formed cells labeled by BrdU. To determine whether, human CPCs (hCPCs) are self-renewing and multipotent, these cells were transduced with the EGFP-lentivirus and injected after acute myocardial infarction in immunosuppressed rats. hCPCs, myocytes, ECs, and fibroblasts collected from the regenerated myocardium showed common viral integration sites in the human genome. Thus, our results indicate that the adult heart contains a pool of resident stem cells that regulate cardiac homeostasis and repair.