Clonality of mouse and human cardiomyogenesis in vivo.
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.
Hosoda
Toru
T
Department of Anesthesia, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
D'Amario
Domenico
D
Cabral-Da-Silva
Mauricio Castro
MC
Zheng
Hanqiao
H
Padin-Iruegas
M Elena
ME
Ogorek
Barbara
B
Ferreira-Martins
João
J
Yasuzawa-Amano
Saori
S
Amano
Katsuya
K
Ide-Iwata
Noriko
N
Cheng
Wei
W
Rota
Marcello
M
Urbanek
Konrad
K
Kajstura
Jan
J
Anversa
Piero
P
Leri
Annarosa
A
D016475:3T3 Cells; D000818:Animals; D001483:Base Sequence; D002454:Cell Differentiation; D019070:Cell Lineage; D049109:Cell Proliferation; D002999:Clone Cells / Q000166:cytology / Q000378:metabolism; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism; D005260:Female; D005347:Fibroblasts / Q000166:cytology / Q000378:metabolism; D005822:Genetic Vectors / Q000235:genetics; D049452:Green Fluorescent Proteins / Q000235:genetics / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D016086:Lentivirus / Q000235:genetics; D051379:Mice; D008969:Molecular Sequence Data; D009206:Myocardium / Q000166:cytology / Q000378:metabolism; D032383:Myocytes, Cardiac / Q000166:cytology* / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011916:Rats, Inbred F344; D011993:Recombinant Fusion Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013997:Time Factors
D011993:Recombinant Fusion Proteins; D049452:Green Fluorescent Proteins; D018995:Myosin Heavy Chains