title: Synergistic effects of the GATA-4-mediated miR-144/451 cluster in protection against simulated ischemia/reperfusion-induced cardiomyocyte death.
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.
authors: Department of Pharmacology and Cell Biophysics, University of Cincinnati College of Medicine, Cincinnati, OH 45267-0575, USA.
authors: Xiaowei
authors: X
authors: Zhang
authors: Xiaohong
authors: X
authors: Wang
authors: Hongyan
authors: H
authors: Zhu
authors: Cheng
authors: C
authors: Zhu
authors: Yigang
authors: Y
authors: Wang
authors: William T
authors: WT
authors: Pu
authors: Anil G
authors: AG
authors: Jegga
authors: Guo-Chang
authors: GC
authors: Fan
mesh_terms: D000375:Aging / Q000187:drug effects / Q000473:pathology; D000818:Animals; D001483:Base Sequence; D016923:Cell Death / Q000187:drug effects; D051546:Cyclooxygenase 2 / Q000378:metabolism; D016861:Cyclooxygenase Inhibitors / Q000494:pharmacology; D050991:GATA4 Transcription Factor / Q000378:metabolism*; D055785:Gene Knockdown Techniques; D006801:Humans; D051379:Mice; D035683:MicroRNAs / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D005810:Multigene Family; D032383:Myocytes, Cardiac / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism / Q000473:pathology*; D016601:RNA-Binding Proteins / Q000235:genetics; D051381:Rats; D015427:Reperfusion Injury / Q000201:enzymology / Q000235:genetics / Q000473:pathology / Q000517:prevention & control*; D015854:Up-Regulation / Q000187:drug effects
chemical_list: D016861:Cyclooxygenase Inhibitors; D050991:GATA4 Transcription Factor; C555034:MIRN144 microRNA, rat; C555035:MIRN451A microRNA, rat; D035683:MicroRNAs; D016601:RNA-Binding Proteins; D051546:Cyclooxygenase 2; C489691:Ptgs2 protein, rat