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Telomerase expression in the mammalian heart
Author(s) -
Richardson Gavin D.,
Breault David,
Horrocks Grace,
Cormack Suzanne,
Hole Nicholas,
Owens W. Andrew
Publication year - 2012
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fj.12-208843
Subject(s) - telomerase , telomerase reverse transcriptase , biology , population , telomere , flow cytometry , microbiology and biotechnology , immunofluorescence , stem cell , green fluorescent protein , cancer research , immunology , medicine , antibody , genetics , gene , environmental health
While the mammalian heart has low, but functionally significant, levels of telomerase expression, the cellular population responsible remains incompletely characterized. This study aimed to identify the cell types responsible for cardiac telomerase activity in neonatal, adult, and cryoinjured adult hearts using transgenic mice expressing green fluorescent protein (GFP), driven by the promoter for murine telomerase reverse transcriptase ( mTert ), which is a necessary and rate‐limiting component of telomerase. A rare population of mTert ‐GFP‐expressing cells was identified that possessed all detectable cardiac telomerase RNA and telomerase activity. It was heterogeneous and included cells coexpressing markers of cardiomyocytic, endothelial, and mesenchymal lineages, putative cardiac stem cell markers, and, interestingly, cardiomyocytes with a differentiated phenotype. Quantification using both flow cytometry and immunofluorescence identified a significant decline in m Tert ‐GFP cells in adult animals compared to neonates (~9‐ and ~20‐fold, respectively). Cardiac injury resulted in a ~6.45‐fold expansion of this population ( P <0.005) compared with sham‐operated controls. This study identifies the cells responsible for cardiac telomerase activity, demonstrates a significant diminution with age but a marked response to injury, and, given the relationship between telomerase activity and stem cell populations, suggests that they represent a potential target for further investigation of cardiac regenerative potential.—Richardson, G. D., Breault, D., Horrocks, G., Cormack, S., Hole, N., Owens, W. A. Telomerase expression in the mammalian heart. FASEB J. 26, 4832–4840 (2012). www.fasebj.org