Project description:Regulation of neural stem cell (NSC) fate decisions is critical during the transition from a multicellular mammalian forebrain neuroepithelium to the multilayered neocortex. Forebrain development requires coordinated vascular investment alongside NSC differentiation. Vascular endothelial growth factor A (Vegf) has proven to be a pleiotrophic gene whose multiple protein isoforms regulate a broad range of effects in neurovascular systems. To test the hypothesis that the Vegf isoforms (120, 164, and 188) are required for normal forebrain development, we analyzed the forebrain transcriptome of mice expressing specific Vegf isoforms, Vegf120, VegfF188, or a combination of Vegf120/188. Transcriptome analysis identified differentially expressed genes in embryonic day (E) 9.5 forebrain, a time point preceding dramatic neuroepithelial expansion and vascular investment in the telencephalon. Meta-analysis identified gene pathways linked to chromosome-level modifications, cell fate regulation, and neurogenesis that were altered in Vegf isoform mice. Twelve E9.5 wildtype forebrain samples were compared to four E9.5 Vegf120 mouse forebrains, four E9.5 Vegf188 mouse forebrains, three E9.5 Vegf120/188 mouse forebrains, and four E11.5 wild type forebrains using the Mouse 430. 2.0 Affymetrix GeneChip. This study comprises of new samples and reanalysis of Samples from GSE30767 and GSE8091.
Project description:Regulation of neural stem cell (NSC) fate decisions is critical during the transition from a multicellular mammalian forebrain neuroepithelium to the multilayered neocortex. Forebrain development requires coordinated vascular investment alongside NSC differentiation. Vascular endothelial growth factor A (Vegf) has proven to be a pleiotrophic gene whose multiple protein isoforms regulate a broad range of effects in neurovascular systems. To test the hypothesis that the Vegf isoforms (120, 164, and 188) are required for normal forebrain development, we analyzed the forebrain transcriptome of mice expressing specific Vegf isoforms, Vegf120, VegfF188, or a combination of Vegf120/188. Transcriptome analysis identified differentially expressed genes in embryonic day (E) 9.5 forebrain, a time point preceding dramatic neuroepithelial expansion and vascular investment in the telencephalon. Meta-analysis identified gene pathways linked to chromosome-level modifications, cell fate regulation, and neurogenesis that were altered in Vegf isoform mice.
Project description:This work was designed to determine the role of the vascular endothelial growth factor A (VEGF) isoforms during early neuroepithelial development in the mammalian central nervous system (CNS), specifically in the forebrain. An emerging model of interdependence between neural and vascular systems includes VEGF, with its dual roles as a potent angiogenesis factor and neural regulator. Although a number of studies have implicated VEGF in CNS development, little is known about the role that the different VEGF isoforms play in early neurogenesis. We used a mouse model of disrupted VEGF isoform expression that eliminates the predominant brain isoform, VEGF164, and expresses only the diffusible form, VEGF120. We tested the hypothesis that VEGF164 plays a key role in controlling neural precursor populations in developing cortex. We used microarray analysis to compare gene expression differences between wild type and VEGF120 mice at E9.5, the primitive stem cell stage of the neuroepithelium. We quantified changes in PHH3-positive nuclei, neural stem cell markers (Pax6 and nestin) and the Tbr2-positive intermediate progenitors at E11.5 when the neural precursor population is expanding rapidly. Absence of VEGF164 (and VEGF188) leads to reduced proliferation without an apparent effect on the number of Tbr2-positive cells. There is a corresponding reduction in the number of mitotic spindles that are oriented parallel to the ventricular surface relative to those with a vertical or oblique angle. These results support a role for the VEGF isoforms in supporting the neural precursor population of the early neuroepithelium. Four samples each of E9.5 wildtype or VEGF120 mouse forebrain were analyzed with the Mouse 430 2.0 Affymetrix GeneChip
Project description:This work was designed to determine the role of the vascular endothelial growth factor A (VEGF) isoforms during early neuroepithelial development in the mammalian central nervous system (CNS), specifically in the forebrain. An emerging model of interdependence between neural and vascular systems includes VEGF, with its dual roles as a potent angiogenesis factor and neural regulator. Although a number of studies have implicated VEGF in CNS development, little is known about the role that the different VEGF isoforms play in early neurogenesis. We used a mouse model of disrupted VEGF isoform expression that eliminates the predominant brain isoform, VEGF164, and expresses only the diffusible form, VEGF120. We tested the hypothesis that VEGF164 plays a key role in controlling neural precursor populations in developing cortex. We used microarray analysis to compare gene expression differences between wild type and VEGF120 mice at E9.5, the primitive stem cell stage of the neuroepithelium. We quantified changes in PHH3-positive nuclei, neural stem cell markers (Pax6 and nestin) and the Tbr2-positive intermediate progenitors at E11.5 when the neural precursor population is expanding rapidly. Absence of VEGF164 (and VEGF188) leads to reduced proliferation without an apparent effect on the number of Tbr2-positive cells. There is a corresponding reduction in the number of mitotic spindles that are oriented parallel to the ventricular surface relative to those with a vertical or oblique angle. These results support a role for the VEGF isoforms in supporting the neural precursor population of the early neuroepithelium.
Project description:Numerous studies have suggested a link between fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF) signaling pathways; however the nature of this link has not been established. To evaluate this relationship we investigated VEGF signaling in endothelial cells with disrupted FGF signaling in vitro and in vivo. We find that endothelial cells lacking FGF signaling become unresponsive to VEGF due to down regulation of VEGFR2 expression caused by reduced Vegfr2 enhancer activation, which is in turn caused by reduced activation of Ets family transcription factors. In vivo this manifests in the loss of vascular integrity and morphogenesis. Thus, basal FGF stimulation of the endothelium is required for maintenance of VEGFR2 expression and the ability to respond to VEGF stimulation and accounts for the hierarchic control of vascular formation by FGFs and VEGF. Primary mouse lung endothelial cells were transduced with either Adeno-Null (empty) or Adeno- dominant negative FGF receptor 1 and harvested 24 hours after transduction. Total RNA was extracted and subjected to the analysis using SuperArray GEArray Q Series Mouse Angiogenesis Gene Array. Comparisons were made between treatments.
Project description:Numerous studies have suggested a link between fibroblast growth factor (FGF) and vascular endothelial growth factor (VEGF) signaling pathways; however the nature of this link has not been established. To evaluate this relationship we investigated VEGF signaling in endothelial cells with disrupted FGF signaling in vitro and in vivo. We find that endothelial cells lacking FGF signaling become unresponsive to VEGF due to down regulation of VEGFR2 expression caused by reduced Vegfr2 enhancer activation, which is in turn caused by reduced activation of Ets family transcription factors. In vivo this manifests in the loss of vascular integrity and morphogenesis. Thus, basal FGF stimulation of the endothelium is required for maintenance of VEGFR2 expression and the ability to respond to VEGF stimulation and accounts for the hierarchic control of vascular formation by FGFs and VEGF.
Project description:HUVECs (human umbilical cord vein endothelial cells) are treated with the angiogenic factors VEGF-A (vascular endothelial growth factor-A) and PlGF (placental growth factor) in low or high serum media.
Project description:Lymphatic vessel growth and activation, mediated by vascular endothelial growth factor- (VEGF)-C and/or VEGF-A, play an important role in metastatic cancer spread and in chronic inflammation. We aimed to comprehensively identify downstream molecular targets induced by VEGF-A or VEGF-C in lymphatic endothelium. To this end, we treated human dermal lymphatic endothelial cells (LEC) with VEGF-A or VEGF-C for up to 24 hours, followed by a time-series transcriptional profiling using gene microarray technology. We identified a number of genes - many of them not previously known to be involved in lymphangiogenesis - that clustered either as early response genes, transiently induced genes or progressively induced genes. Endothelial specific molecule-1 (ESM-1) was one of the genes that were most potently induced by both VEGF-A and VEGF-C. Keywords: Time course, growth factor comparison
Project description:The project concerns vascular endothelial growth factor (VEGF) signaling, which is dependent on binding of VEGF to VEGF receptor-2 (VEGFR2) and leads to activation of the receptor kinase and autophosphorylation. Previous mouse studies with the VEGFR-2 phosphorylation site mutation Y1212F showed reduced vascular stability. We here investigate with LC-MS proteomics which signal transduction pathway(s) are lost in the mutant by identifying proteins that bind to the Y1212F site.