Revealing new mouse epicardial cell markers through transcriptomics.
BACKGROUND
The epicardium has key functions during myocardial development, by contributing to the formation of coronary endothelial and smooth muscle cells, cardiac fibroblasts, and potentially cardiomyocytes. The epicardium plays a morphogenetic role by emitting signals to promote and maintain cardiomyocyte proliferation. In a regenerative context, the adult epicardium might comprise a progenitor cell population that can be induced to contribute to cardiac repair. Although some genes involved in epicardial function have been identified, a detailed molecular profile of epicardial gene expression has not been available.


METHODS
Using laser capture microscopy, we isolated the epicardial layer from the adult murine heart before or after cardiac infarction in wildtype mice and mice expressing a transgenic IGF-1 propeptide (mIGF-1) that enhances cardiac repair, and analyzed the transcription profile using DNA microarrays.


RESULTS
Expression of epithelial genes such as basonuclin, dermokine, and glycoprotein M6A are highly enriched in the epicardial layer, which maintains expression of selected embryonic genes involved in epicardial development in mIGF-1 transgenic hearts. After myocardial infarct, a subset of differentially expressed genes are down-regulated in the epicardium representing an epicardium-specific signature that responds to injury.


CONCLUSIONS
This study presents the description of the murine epicardial transcriptome obtained from snap frozen tissues, providing essential information for further analysis of this important cardiac cell layer.
Bochmann
Lars
L
Mouse Biology Unit, European Molecular Biology Laboratory, Monterotondo, Italy. bochmann@embl.it
Sarathchandra
Padmini
P
Mori
Federica
F
Lara-Pezzi
Enrique
E
Lazzaro
Domenico
D
Rosenthal
Nadia
N
D000818:Animals; D015415:Biomarkers; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation; D007334:Insulin-Like Growth Factor I / Q000235:genetics; D051379:Mice; D008822:Mice, Transgenic; D009203:Myocardial Infarction / Q000235:genetics; D020411:Oligonucleotide Array Sequence Analysis; D010496:Pericardium / Q000166:cytology*
D015415:Biomarkers; D007334:Insulin-Like Growth Factor I