title: Downregulation of microRNA-29 by antisense inhibitors and a PPAR-gamma agonist protects against myocardial ischaemia-reperfusion injury.
abstract: OBJECTIVE
  MicroRNAs (miRNAs) regulate various cardiac processes including cell proliferation and apoptosis. Pioglitazone (PIO), a peroxisome proliferator-activated receptor (PPAR)-gamma agonist, protects against myocardial ischaemia-reperfusion (IR) injury. We assessed the effects of PPAR-gamma activation on myocardial miRNA levels and the role of miRNAs in IR injury.
  
  
  RESULTS
  We evaluated the expression changes of miRNAs in the rat heart after PIO administration using miRNA arrays and then confirmed the result by northern blot. miR-29a and c levels decreased remarkably after 7-day treatment with PIO. In H9c2 cells, the effects of PIO and rosiglitazone on miR-29 expression levels were blocked by a selective PPAR-gamma inhibitor GW9662. Downregulation of miR-29 by antisense inhibitor or by PIO protected H9c2 cells from simulated IR injury, indicated as increased cell survival and decreased caspase-3 activity. In contrast, overexpressing miR-29 promoted apoptosis and completely blocked the protective effect of PIO. Antagomirs against miR-29a or -29c significantly reduced myocardial infarct size and apoptosis in hearts subjected to IR injury. Western blot analyses demonstrated that Mcl-2, an anti-apoptotic Bcl-2 family member, was increased by miR-29 inhibition.
  
  
  CONCLUSIONS
  Downregulation of miR-29 protected hearts against IR injury. The modulation of miRNAs can be achieved by pharmacological intervention. These findings provide a rationale for the development of miRNA-based strategies for the attenuation of IR injury.
authors.affiliation: Department of Biochemistry and Molecular Biology, University of Texas Medical Branch, MRB 5:108, 301 University Boulevard, Galveston, TX 77555, USA. yumye@utmb.edu
authors.forename: Yumei
authors.initials: Y
authors.lastname: Ye
authors.forename: Zhaoyong
authors.initials: Z
authors.lastname: Hu
authors.forename: Yu
authors.initials: Y
authors.lastname: Lin
authors.forename: Congfang
authors.initials: C
authors.lastname: Zhang
authors.forename: Jose R
authors.initials: JR
authors.lastname: Perez-Polo
mesh_terms: D000813:Anilides / Q000494:pharmacology; D000818:Animals; D017209:Apoptosis / Q000187:drug effects; D015152:Blotting, Northern; D015153:Blotting, Western; D053148:Caspase 3 / Q000378:metabolism; D002460:Cell Line; D002470:Cell Survival / Q000187:drug effects; D004195:Disease Models, Animal; D015536:Down-Regulation; D020869:Gene Expression Profiling / Q000379:methods; D051379:Mice; D035683:MicroRNAs / Q000378:metabolism*; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D015428:Myocardial Reperfusion Injury / Q000235:genetics / Q000378:metabolism / Q000473:pathology / Q000517:prevention & control*; D009206:Myocardium / Q000378:metabolism* / Q000473:pathology; D020411:Oligonucleotide Array Sequence Analysis; D016376:Oligonucleotides, Antisense / Q000378:metabolism*; D047495:PPAR gamma / Q000819:agonists* / Q000037:antagonists & inhibitors / Q000378:metabolism; D010766:Phosphorylation; D000077205:Pioglitazone; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D019253:Proto-Oncogene Proteins c-bcl-2 / Q000378:metabolism; D051381:Rats; D000077154:Rosiglitazone; D045162:Thiazolidinediones / Q000494:pharmacology*; D013997:Time Factors; D014162:Transfection; D051028:bcl-2-Associated X Protein / Q000378:metabolism
chemical_list: C457499:2-chloro-5-nitrobenzanilide; D000813:Anilides; C494827:Bax protein, mouse; C547014:MIRN29 microRNA, mouse; C526366:MIRN29 microRNA, rat; D035683:MicroRNAs; D064549:Myeloid Cell Leukemia Sequence 1 Protein; D016376:Oligonucleotides, Antisense; D047495:PPAR gamma; D019253:Proto-Oncogene Proteins c-bcl-2; D045162:Thiazolidinediones; D051028:bcl-2-Associated X Protein; D000077154:Rosiglitazone; D051057:Proto-Oncogene Proteins c-akt; C505410:Casp3 protein, rat; D053148:Caspase 3; D000077205:Pioglitazone