title: Permissive role of miR-663 in induction of VEGF and activation of the ATF4 branch of unfolded protein response in endothelial cells by oxidized phospholipids.
abstract: OBJECTIVE
  Atherosclerotic lesions contain high concentrations of oxidized phospholipids (OxPLs) known to induce VEGF via the ATF4 arm of unfolded protein response (UPR), and to promote angiogenic reactions thus potentially contributing to the progression and destabilization of atherosclerotic plaques. In order to get further insights into the mechanisms of cellular stress-induced angiogenesis we studied the role of a specific microRNA (miR-663) in the mechanisms of VEGF induction by OxPLs and inducers of UPR.
  
  
  METHODS
  miRNA and mRNA levels were determined using microarray profiling and qRT-PCR methods. Proteins were analyzed by Western blotting. miR-663 levels were changed by transfecting cells with synthetic oligonucleotides.
  
  
  RESULTS
  OxPAPC elevated miR-663 in two types of human endothelial cells (ECs). Knockdown of miR-663 inhibited upregulation of VEGF mRNA in ECs treated by OxPAPC, OxPAPS or OxPAPA. In addition, silencing of miR-663 suppressed upregulation by OxPAPC of ATF4 mRNA and protein, as well as a downstream gene TRIB. Similarly to the inhibition of OxPAPC effects, knockdown of miR-663 suppressed elevation of ATF4, VEGF and TRIB in response to another inducer of UPR, tunicamycin. Overexpression of miR-663 reversed the inhibition of VEGF induction by miR-663 inhibitor.
  
  
  CONCLUSIONS
  miR-663 is critically important for 2 key events induced in ECs by stress agents and oxidized lipids, namely induction of transcription factor ATF4 and its downstream gene VEGF. These findings allow hypothesizing that miR-663 plays a general role in control of the ATF4 branch of UPR induced by different agents.
authors: Department of Vascular Biology and Thrombosis Research, Centre of Physiology and Pharmacology, Medical University of Vienna, Schwarzspanierstrasse 17, A-1090 Vienna, Austria.
authors: Taras
authors: T
authors: Afonyushkin
authors: Olga V
authors: OV
authors: Oskolkova
authors: Valery N
authors: VN
authors: Bochkov
mesh_terms: D051701:Activating Transcription Factor 4 / Q000378:metabolism*; D042783:Endothelial Cells / Q000378:metabolism; D061307:Human Umbilical Vein Endothelial Cells; D006801:Humans; D035683:MicroRNAs / Q000037:antagonists & inhibitors / Q000502:physiology*; D010084:Oxidation-Reduction; D010713:Phosphatidylcholines; D010743:Phospholipids / Q000378:metabolism; D014415:Tunicamycin / Q000494:pharmacology; D056811:Unfolded Protein Response / Q000187:drug effects*; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis*
chemical_list: C552243:MIRN663 microRNA, human; D035683:MicroRNAs; D010713:Phosphatidylcholines; D010743:Phospholipids; D042461:Vascular Endothelial Growth Factor A; C472349:oxidized-L-alpha-1-palmitoyl-2-arachidonoyl-sn-glycero-3-phosphorylcholine; D014415:Tunicamycin; D051701:Activating Transcription Factor 4