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Cell Death Differ. 2017 Dec;24(12):2101-2116. doi: 10.1038/cdd.2017.130. Epub 2017 Aug 11.

Adult cardiac stem cells are multipotent and robustly myogenic: c-kit expression is necessary but not sufficient for their identification.

Author information

1
Molecular and Cellular Cardiology, Department of Medical and Surgical Sciences, Magna Græcia University, 88100 Catanzaro, Italy.
2
Bioinformatics Laboratory, Department of Medical and Surgical Sciences, Magna Graecia University, 88100 Catanzaro, Italy.
3
School of Basic and Medical Biosciences, Faculty of Life Sciences & Medicine, Kings College London, Guy's campus, London SE1 1UL, UK.
4
Laboratory of Cell Electrophysiology, National Heart and Lung Institute, Imperial College, London SW7 2AZ, UK.
5
TIGEM (Telethon Institute of Genetics and Medicine) and Department of Biochemistry, Biophysics and Molecular Pathology, Second University of Naples, Naples, Italy.
6
School of Biomedical Sciences, Faculty of Biological Sciences, University of Leeds, Leeds LS2 9JT, UK.
7
Interdepartmental Veterinary Services Centre, Department of Health Sciences, Magna Græcia University of Catanzaro, 88100 Catanzaro, Italy.

Abstract

Multipotent adult resident cardiac stem cells (CSCs) were first identified by the expression of c-kit, the stem cell factor receptor. However, in the adult myocardium c-kit alone cannot distinguish CSCs from other c-kit-expressing (c-kitpos) cells. The adult heart indeed contains a heterogeneous mixture of c-kitpos cells, mainly composed of mast and endothelial/progenitor cells. This heterogeneity of cardiac c-kitpos cells has generated confusion and controversy about the existence and role of CSCs in the adult heart. Here, to unravel CSC identity within the heterogeneous c-kit-expressing cardiac cell population, c-kitpos cardiac cells were separated through CD45-positive or -negative sorting followed by c-kitpos sorting. The blood/endothelial lineage-committed (Lineagepos) CD45posc-kitpos cardiac cells were compared to CD45neg(Lineageneg/Linneg) c-kitpos cardiac cells for stemness and myogenic properties in vitro and in vivo. The majority (~90%) of the resident c-kitpos cardiac cells are blood/endothelial lineage-committed CD45posCD31posc-kitpos cells. In contrast, the LinnegCD45negc-kitpos cardiac cell cohort, which represents ⩽10% of the total c-kitpos cells, contain all the cardiac cells with the properties of adult multipotent CSCs. These characteristics are absent from the c-kitneg and the blood/endothelial lineage-committed c-kitpos cardiac cells. Single Linnegc-kitpos cell-derived clones, which represent only 1-2% of total c-kitpos myocardial cells, when stimulated with TGF-β/Wnt molecules, acquire full transcriptome and protein expression, sarcomere organisation, spontaneous contraction and electrophysiological properties of differentiated cardiomyocytes (CMs). Genetically tagged cloned progeny of one Linnegc-kitpos cell when injected into the infarcted myocardium, results in significant regeneration of new CMs, arterioles and capillaries, derived from the injected cells. The CSC's myogenic regenerative capacity is dependent on commitment to the CM lineage through activation of the SMAD2 pathway. Such regeneration was not apparent when blood/endothelial lineage-committed c-kitpos cardiac cells were injected. Thus, among the cardiac c-kitpos cell cohort only a very small fraction has the phenotype and the differentiation/regenerative potential characteristics of true multipotent CSCs.

PMID:
28800128
PMCID:
PMC5686347
DOI:
10.1038/cdd.2017.130
[Indexed for MEDLINE]
Free PMC Article

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