Abstract 18609: MicroRNA-539 Upregulation Suppresses O-GlcNAcase in the Failing Heart
Background: Cardiac metabolism and related signaling pathways are significantly altered in the failing heart. One such signal, O-linked β-N-acetylglucosamine (O-GlcNAc), represents an essential post-translational modification that modulates the function of many nuclear and cytoplasmic proteins, and, does so in a variety of diseases. O-GlcNAc modification is controlled by two antagonistic enzymes: O-GlcNAc transferase (OGT; adds O-GlcNAc) and O-GlcNAcase (OGA; removes O-GlcNAc). We recently reported reduced OGA expression in the failing heart, which is consistent with the pro-adaptive role of increased O-GlcNAcylation during heart failure; however, mechanisms of OGA regulation during heart failure remain unknown.
Methods and Results: Using miRNA microarray analysis, we observed changes of several miRNAs at 5 d and 28 d post-myocardial infarction in mice (n=4/group) and, specifically, that miR-539 is significantly (p<0.05) elevated. Subsequent qRT-PCR analysis confirmed significant (p<0.05) upregulation of miR-539 at both time points (4.8 fold at 5 d and 2.9 fold at 28 d) in infarcted hearts compared to sham hearts. TargetScan predicted OGA as a potential target of miR-539. Indeed, co-transfection of OGA-3’UTR containing reporter plasmid and miR-539 overexpression plasmid significantly reduced the reporter activity compared to control in transiently transfected HEK 293 cells. To establish whether miR-539 suppresses OGA expression in cardiomyocytes, lentivirus based miR-539 overexpression system was used to transduce neonatal rat cardiomyocytes. Western blot analysis showed significant (~50%; p<0.05) reduction of OGA protein expression.
Conclusion: These results demonstrate that miR-539 is upregulated during heart failure, binds to OGA-3’UTR, and can significantly suppress OGA expression in cardiomyocytes. This work identifies the first target of miR-539 in the heart and the first miRNA that regulates OGA. Manipulation of miR-539 may represent a novel potential therapeutic target in the treatment of heart failure and other metabolic diseases.
- © 2013 by American Heart Association, Inc.