MicroRNAs in the human heart: a clue to fetal gene reprogramming in heart failure.
BACKGROUND
Chronic heart failure is characterized by left ventricular remodeling and reactivation of a fetal gene program; the underlying mechanisms are only partly understood. Here we provide evidence that cardiac microRNAs, recently discovered key regulators of gene expression, contribute to the transcriptional changes observed in heart failure.


RESULTS
Cardiac transcriptome analyses revealed striking similarities between fetal and failing human heart tissue. Using microRNA arrays, we discovered profound alterations of microRNA expression in failing hearts. These changes closely mimicked the microRNA expression pattern observed in fetal cardiac tissue. Bioinformatic analysis demonstrated a striking concordance between regulated messenger RNA expression in heart failure and the presence of microRNA binding sites in the respective 3' untranslated regions. Messenger RNAs upregulated in the failing heart contained preferentially binding sites for downregulated microRNAs and vice versa. Mechanistically, transfection of cardiomyocytes with a set of fetal microRNAs induced cellular hypertrophy as well as changes in gene expression comparable to the failing heart.


CONCLUSIONS
Our data support a novel mode of regulation for the transcriptional changes in cardiac failure. Reactivation of a fetal microRNA program substantially contributes to alterations of gene expression in the failing human heart.
Thum
Thomas
T
University of Würzburg, University Hospital, Department of Internal Medicine I, Cardiology, Würzburg, Germany. Thum_T@klinik.uni-wuerzburg.de
Galuppo
Paolo
P
Wolf
Christian
C
Fiedler
Jan
J
Kneitz
Susanne
S
van Laake
Linda W
LW
Doevendans
Pieter A
PA
Mummery
Christine L
CL
Borlak
Jürgen
J
Haverich
Axel
A
Gross
Carina
C
Engelhardt
Stefan
S
Ertl
Georg
G
Bauersachs
Johann
J
D000328:Adult; D001665:Binding Sites / Q000235:genetics; D005318:Fetal Heart / Q000378:metabolism / Q000502:physiology*; D018507:Gene Expression Regulation, Developmental / Q000235:genetics*; D006333:Heart Failure / Q000235:genetics* / Q000378:metabolism; D006801:Humans; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000096:biosynthesis* / Q000235:genetics*
D035683:MicroRNAs