title: Ras/MAPK signaling modulates VEGFR-3 expression through Ets-mediated p300 recruitment and histone acetylation on the Vegfr3 gene in lymphatic endothelial cells.
abstract: Modulation of VEGFR-3 expression is important for altering lymphatic endothelial cell (LEC) characteristics during the lymphangiogenic processes that occur under developmental, physiological, and pathological conditions. However, the mechanisms underlying the modulation of Vegfr3 gene expression remain largely unknown. Using genetically engineered mice and LECs, we demonstrated previously that Ras signaling is involved not only in VEGFR-3-induced signal transduction but also in Vegfr3 gene expression. Here, we investigated the roles of the transcription factor Ets and the histone acetyltransferase p300 in LECs in Ras-mediated transcriptional regulation of Vegfr3. Ras activates Ets proteins via MAPK-induced phosphorylation. Ets knockdown, similar to Ras knockdown, resulted in a decrease in both Vegfr3 transcript levels and acetylated histone H3 on the Vegfr3 gene. Vegfr3 knockdown results in altered LEC phenotypes, such as aberrant cell proliferation and network formation, and Ets knockdown led to milder but similar phenotypic changes. We identified evolutionarily conserved, non-coding regulatory elements within the Vegfr3 gene that harbor Ets-binding motifs and have enhancer activities in LECs. Chromatin immunoprecipitation (ChIP) assays revealed that acetylated histone H3 on the regulatory elements of the Vegfr3 gene was decreased following Ras and Ets knockdown, and that activated Ets proteins, together with p300, were associated with these regulatory elements, consistent with a reduction in Vegfr3 gene expression in p300-knockdown LECs. Our findings demonstrate a link between Ras signaling and Ets- and p300-mediated transcriptional regulation of Vegfr3, and provide a potential mechanism by which VEGFR-3 expression levels may be modulated during lymphangiogenesis.
authors.affiliation: Laboratory of Developmental Genetics, Center for Experimental Medicine and Systems Biology, The Institute of Medical Science, The University of Tokyo, Tokyo, Japan.
authors.forename: Taeko
authors.initials: T
authors.lastname: Ichise
authors.forename: Nobuaki
authors.initials: N
authors.lastname: Yoshida
authors.forename: Hirotake
authors.initials: H
authors.lastname: Ichise
mesh_terms: D000107:Acetylation; D000818:Animals; D000831:Animals, Newborn; D002478:Cells, Cultured; D002843:Chromatin / Q000235:genetics; D047369:Chromatin Immunoprecipitation; D050881:E1A-Associated p300 Protein / Q000235:genetics / Q000378:metabolism*; D042783:Endothelial Cells / Q000166:cytology / Q000378:metabolism*; D018507:Gene Expression Regulation, Developmental; D008156:Luciferases / Q000378:metabolism; D042583:Lymphangiogenesis; D051379:Mice; D008810:Mice, Inbred C57BL; D020928:Mitogen-Activated Protein Kinases / Q000235:genetics / Q000378:metabolism*; D010766:Phosphorylation; D011401:Promoter Regions, Genetic / Q000235:genetics; D011499:Protein Processing, Post-Translational; D050783:Proto-Oncogene Proteins c-ets / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*; D034741:RNA, Small Interfering / Q000235:genetics; D015398:Signal Transduction; D015533:Transcriptional Activation; D040321:Vascular Endothelial Growth Factor Receptor-3 / Q000235:genetics* / Q000378:metabolism; D018631:ras Proteins / Q000037:antagonists & inhibitors / Q000235:genetics / Q000378:metabolism*
chemical_list: D002843:Chromatin; D050783:Proto-Oncogene Proteins c-ets; D034741:RNA, Small Interfering; D008156:Luciferases; D050881:E1A-Associated p300 Protein; C494361:Ep300 protein, mouse; D040321:Vascular Endothelial Growth Factor Receptor-3; D020928:Mitogen-Activated Protein Kinases; D018631:ras Proteins