|Antagonistic function of the RNA-binding protein HuR and miR-200b in post-transcriptional regulation of vascular endothelial growth factor-A expression and angiogenesis.
|Year of Publication
|Chang S-H, Lu Y-C, Li X, Hsieh W-Y, Xiong Y, Ghosh M, Evans T, Elemento O, Hla T
|J Biol Chem
|2013 Feb 15
|3' Untranslated Regions, Amino Acid Sequence, Animals, CD11b Antigen, ELAV Proteins, Enzyme-Linked Immunosorbent Assay, Gene Deletion, Gene Expression Regulation, Developmental, HEK293 Cells, Humans, Macrophages, Mice, MicroRNAs, Molecular Sequence Data, Neovascularization, Pathologic, Vascular Endothelial Growth Factor A, Zebrafish
HuR, also known as Elavl1, is an RNA-binding protein that regulates embryonic development, progenitor cell survival, and cell stress responses. The role of HuR in angiogenesis is not known. Using a myeloid-specific HuR knock-out mouse model (Elavl1Mø KO), we show that HuR expression in bone marrow-derived macrophages (BMDMs) is needed to maintain the expression of genes enriched in AU-rich elements and U-rich elements in the 3'-UTR. In addition, BMDMs from Elavl1Mø KO mice also showed alterations in expression of several miRNAs. Interestingly, computational analysis suggested that miR-200b, which is up-regulated in Elavl1Mø KO BMDMs, interacts with myeloid mRNAs very close to the HuR binding sites, suggesting competitive regulation of gene expression. One such mRNA encodes vascular endothelial growth factor (VEGF)-A, a major regulator of angiogenesis. Immunoprecipitation of RNA-protein complexes and luciferase reporter assays indicate that HuR antagonizes the suppressive activity of miR-200b, down-regulates miR-200b expression, and promotes VEGF-A expression. Indeed, Vegf-a and other angiogenic regulatory transcripts were down-regulated in Elavl1Mø KO BMDMs. Interestingly, tumor growth, angiogenesis, vascular sprouting, branching, and permeability were significantly attenuated in Elavl1Mø KO mice, suggesting that HuR-regulated myeloid-derived factors modulate tumor angiogenesis in trans. Zebrafish embryos injected with an elavl1 morpholino oligomer or miR-200b mimic showed angiogenesis defects in the subintestinal vein plexus, and elavl1 mRNA rescued the repressive effect of miR-200b. In addition, miR-200b and HuR morpholino oligomer suppressed the activity of a zVEGF 3'-UTR luciferase reporter construct. Together, these studies reveal an evolutionarily conserved post-transcriptional mechanism involving competitive interactions between HuR and miR-200b that controls angiogenesis.
|J. Biol. Chem.
|PubMed Central ID
|HL49094 / HL / NHLBI NIH HHS / United States
R01 HL049094 / HL / NHLBI NIH HHS / United States
HL56182 / HL / NHLBI NIH HHS / United States
R01 HL056182 / HL / NHLBI NIH HHS / United States
R01 HL111400 / HL / NHLBI NIH HHS / United States
R37 HL056182 / HL / NHLBI NIH HHS / United States