Synergistic effects of the GATA-4-mediated miR-144/451 cluster in protection against simulated ischemia/reperfusion-induced cardiomyocyte death

• Published in: Journal of molecular and cellular cardiology Vol. 49; no. 5; pp. 841 - 850
• Main Authors: Zhang, Xiaowei, Wang, Xiaohong, Zhu, Hongyan, Zhu, Cheng, Wang, Yigang, Pu, William T, Jegga, Anil G, Fan, Guo-Chang
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01-11-2010
• Subjects: Aging - drug effects; Aging - pathology; Animals; Apoptosis; Base Sequence; Cardiomyocyte; Cardiovascular; Cell Death - drug effects; COX-2; Cyclooxygenase 2 - metabolism; Cyclooxygenase Inhibitors - pharmacology; GATA4 Transcription Factor - metabolism; Gene Knockdown Techniques; Humans; Mice; microRNA; MicroRNAs - genetics; MicroRNAs - metabolism; Molecular Sequence Data; Multigene Family; Myocytes, Cardiac - drug effects; Myocytes, Cardiac - enzymology; Myocytes, Cardiac - metabolism; Myocytes, Cardiac - pathology; Oxidative stress; Rats; Reperfusion Injury - enzymology; Reperfusion Injury - genetics; Reperfusion Injury - pathology; Reperfusion Injury - prevention & control; RNA-Binding Proteins - genetics; Up-Regulation - drug effects; Oxidative stress; microRNA; COX-2; Cardiomyocyte; Apoptosis
• ISSN: 0022-2828; 1095-8584
• DOI: 10.1016/j.yjmcc.2010.08.007

Abstract Among the identified microRNAs (miRs) thus far, ~ 50% of mammalian miRs are clustered in the genome and transcribed as polycistronic primary transcripts. However, whether clustered miRs mediate non-redundant and cooperative functions remains poorly understood. In this study, we first identified activation of the promoter of miR-144/451 by GATA-4, a critical transcription factor in the heart. Next, we observed that ectopic expression of miR-144 and -451 individually augmented cardiomyocyte survival, which was further improved by overexpression of miR-144/451, compared to control cells in response to simulated ischemia/reperfusion. In contrast, knockdown of endogenous miR-144 and -451 revealed opposite effects. Using luciferase reporter assay and western blot analysis, we also validated that both miR-144 and miR-451 target CUG triplet repeat-binding protein 2 (CUGBP2), a ubiquitously expressed RNA-binding protein, known to interact with COX-2 3′UTR and inhibit its translation. Accordingly, protein levels of CUGBP2 were greatly reduced and COX-2 activity was markedly increased in miR-144-, miR-451-, and miR-144/451-overexpressing cardiomyocytes, compared to GFP cells. Furthermore, inhibition of COX-2 activity by either NS-398 or DUP-697 partially offset protective effects of the miR-144/451 cluster. Together, these data indicate that both partners of the miR-144/451 cluster confer protection against simulated I/R-induced cardiomyocyte death via targeting CUGBP2–COX-2 pathway, at least in part. Thus, both miR-144 and miR-451 may represent new therapeutic agents for the treatment of ischemic heart disease.