title: Post-transcriptional regulation of VEGF-A mRNA levels by mitogen-activated protein kinases (MAPKs) during metabolic stress associated with ischaemia/reperfusion.
abstract: Angiogenesis is a well-characterised response to the metabolic stresses that occur during ischaemia/reperfusion, but the signalling pathways that regulate it are poorly understood. We tested whether activation of mitogen-activated protein kinases (MAPKs) was involved in regulating the expression of pro-angiogenic growth factors by the metabolic stresses associated with ischaemia/reperfusion in H9c2 rat cardiomyoblasts. Metabolic stress had no effect on vascular endothelial growth factor (VEGF) mRNA levels, but recovery after metabolic inhibition led to a strong induction of VEGF-A mRNA (3.8 ± 0.5-fold at 4 h), a modest rise in VEGF-C mRNA levels (1.7 ± 0.3-fold at 4 h), with no effect on VEGF-B or -D. A VEGF-A promoter reporter construct was unresponsive to metabolic inhibition/recovery and increases in VEGF-A mRNA were not blocked by the transcription inhibitor actinomycin D suggesting that increases in VEGF mRNA were due to enhanced VEGF-A mRNA stability. In addition, studies using reporter constructs demonstrated that regions within the 5' untranslated region (UTR) contributed to enhanced mRNA stability following recovery from metabolic stress. Increases in VEGF-A mRNA were abolished by inhibition of extracellular signal-regulated kinase or c-jun N-terminal kinase MAPKs, suggesting that these kinases may promote angiogenesis in response to metabolic stress during ischaemia/reperfusion by increasing VEGF-A message stability.
authors.affiliation: Department of Biochemistry, University of Leicester, Leicester, UK.
authors.forename: Bryan W
authors.initials: BW
authors.lastname: Miller
authors.forename: Joanna M
authors.initials: JM
authors.lastname: Hay
authors.forename: Sally A
authors.initials: SA
authors.lastname: Prigent
authors.forename: Martin
authors.initials: M
authors.lastname: Dickens
mesh_terms: D000818:Animals; D004789:Enzyme Activation; D005786:Gene Expression Regulation; D020935:MAP Kinase Signaling System; D020928:Mitogen-Activated Protein Kinases / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic; D047428:Protein Kinase Inhibitors / Q000494:pharmacology; D011499:Protein Processing, Post-Translational; D012323:RNA Processing, Post-Transcriptional; D020871:RNA Stability; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D015427:Reperfusion Injury; D013312:Stress, Physiological; D015533:Transcriptional Activation; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics* / Q000378:metabolism
chemical_list: D047428:Protein Kinase Inhibitors; D012333:RNA, Messenger; D042461:Vascular Endothelial Growth Factor A; C467498:vascular endothelial growth factor A, rat; D020928:Mitogen-Activated Protein Kinases