Abstract 20439: Generation of Novel Fluorescent Reporter Cells and Transgenic Mice for Identification and Characterization of Cardiomyocytes Derived From Adrenergic Progenitor Cells
Intrinsic cardiac adrenergic cells contribute to pacemaking, conduction, and working myocardium during prenatal heart development. To study these cells, we generated knock-in transgenic mice that express the enhanced green fluorescent protein (EGFP) in the adrenergic gene locus encoding for the enzyme, phenylethanolamine n-methyltransferase (Pnmt), which was the marker of adrenergic cells. Here, we show that Pnmt-EGFP knock-in transgenic mice transiently expressed EGFP in cardiomyocytes near the atrioventricular junction of embryonic mouse hearts. As expected EGFP was highly expressed in adrenal chromaffin cells, thereby indicating that EGFP expression faithfully recapitulated endogenous Pnmt gene expression. To study the properties and utility of adrenergic progenitors cells for cardiomyocyte stem cell therapies, we have produced a number of clonal mouse embryonic stem cell (mESC) lines where the Cre-recombinase gene is knocked-in to the Pnmt gene locus (Pnmt-Cre), and a “STOP-GO” reporter plasmid is stably expressed. In undifferentiated pluripotent mESCs, the cells display red fluorescence (“STOP” indicator). However, when differentiated into cardiomyocytes, a subset of these cells transiently become adrenergic and thus express the Cre-recombinase gene from the Pnmt locus. In this subset of mESCs, Cre-recombinase acts on the reporter plasmid to convert it from red to green (“GO” indicator) fluorescence, thereby allowing us to selectively identify, isolate, and characterize adrenergic-derived cardiomyocytes. Ongoing studies are aimed at determining how these myocytes differ from those that do not pass through an adrenergic lineage, and whether or not they confer any selective advantages for stem cell regenerative medicine strategies to repair or replace damaged myocardium.
- © 2010 by American Heart Association, Inc.