Project description:This SuperSeries is composed of the following subset Series:; GSE16691: Transcriptional regulation by Norrin-Frizzled4 signaling in the embryonic yolk sac; GSE16703: Long-term effect on the transcriptome of a decrement in Norrin/Frizzled4/Lrp signaling in retinal endothelial cells; GSE16705: Transcriptional response to Frizzled4 signaling in cultured retinal endothelial cells; GSE16707: Long-term effect on the transcriptome of loss of Frizzled4 signaling in cerebellar endothelial cells Experiment Overall Design: Refer to individual Series
Project description:Transcriptional profiles of the embryonic yolk sac from embryos with ectopic Norrin expression were compared to their wild type littermate controls. The goal is to identify the transcriptional response to Norrin-Frizzled 4 signaling during embryonic angiogenesis.
Project description:Transcriptional profiles of the embryonic yolk sac from embryos with ectopic Norrin expression were compared to their wild type littermate controls. The goal is to identify the transcriptional response to Norrin-Frizzled 4 signaling during embryonic angiogenesis. Experiment Overall Design: Ectopic Norrin expression was achieved using a conditional over-expression strategy. Yolk sacs from 3-5 embryos were pooled for each sample and 3 replicates of both control and experimental groups were analyzed.
Project description:Using mice with targeted gene mutations, we identify (1) distinct roles for different canonical Wnt signaling components in central nervous system (CNS) vascular development and in the specification of the blood-brain and blood-retina barriers (BBB and BRB) and (2) differential sensitivities of the vasculature in various CNS regions to perturbations in canonical Wnt signaling components. We find nearly equivalent roles for Lrp5 and Lrp6 in brain vascular development and barrier maintenance but a dominant role for Lrp5 in the retinal vasculature, an especially high sensitivity of the BBB in the cerebellum and pons/interpeduncular nuclei to decrements in canonical Wnt signaling, and plasticity in the barrier properties of mature CNS vasculature. Brain and retinal vascular defects caused by loss of Norrin/Frizzled4 signaling can be fully rescued by stabilizing beta-catenin, and loss of beta-catenin’s transcriptional activation domain or expression of a dominant negative Tcf4 recapitulates the vascular development and barrier defects seen with loss of receptor, co-receptor, or ligand, indicating that Norrin/Frizzled4 signaling acts predominantly by beta-catenin-dependent transcriptional regulation. This work strongly supports a model in which identical or nearly identical canonical Wnt signaling mechanisms mediate neural tube and retinal vascularization and maintain the BBB and BRB. Total retina RNA from P10 WT, NdpKO, Ctnnb1flex3/+;Pdgfb-CreER, and NdpKO;Ctnnb1flex3/+;Pdgfb-CreER mice was subjected to RNAseq
Project description:Using mice with targeted gene mutations, we identify (1) distinct roles for different canonical Wnt signaling components in central nervous system (CNS) vascular development and in the specification of the blood-brain and blood-retina barriers (BBB and BRB) and (2) differential sensitivities of the vasculature in various CNS regions to perturbations in canonical Wnt signaling components. We find nearly equivalent roles for Lrp5 and Lrp6 in brain vascular development and barrier maintenance but a dominant role for Lrp5 in the retinal vasculature, an especially high sensitivity of the BBB in the cerebellum and pons/interpeduncular nuclei to decrements in canonical Wnt signaling, and plasticity in the barrier properties of mature CNS vasculature. Brain and retinal vascular defects caused by loss of Norrin/Frizzled4 signaling can be fully rescued by stabilizing beta-catenin, and loss of beta-catenin’s transcriptional activation domain or expression of a dominant negative Tcf4 recapitulates the vascular development and barrier defects seen with loss of receptor, co-receptor, or ligand, indicating that Norrin/Frizzled4 signaling acts predominantly by beta-catenin-dependent transcriptional regulation. This work strongly supports a model in which identical or nearly identical canonical Wnt signaling mechanisms mediate neural tube and retinal vascularization and maintain the BBB and BRB.
Project description:The signaling cascades that direct the morphological differentiation of the vascular system during early embryogenesis are not well defined. To further understand the role of Notch signaling during endothelial differentiation, this study uses both an in vivo gain-of-function and in vivo loss-of-function approach. At embryonic day 9.5, embryos with activated Notch1 signaling in the endothelia display a variety of growth and cardiovascular defects, and die soon after E10.5. Most notably, the extra-embryonic vasculature of the yolk sac displays remodeling differentiation defects. In the wild-type yolk sac, the primary vascular network has begun to reorganize, forming the large primary vessels and the smaller capillaries. In the activated Notch1 embryos remodeling is defective; the vasculature have an enlarged surface with decreased inter-vessel space. Embryos with ablated Notch signaling also display growth and vascular defects at E9.5 similar to the activated Notch1 embryos, however they exhibit a lack of vascular remodeling in the yolk sac, retaining the simple vascular plexus seen at E8.5. These results indicate that Notch signaling plays a critical role in the remodeling of the vasculature in the early embryo, particularly in the extra embryonic region. A conditional transgenic system was used in this study to activate Notch signaling. The ubiquitous ROSA26Notch transgene with a Neo/stop cassette flanked by loxP sites, followed by the N1-ICD cDNA, was recombined with a Tie2-CRE mouse, resulting in the removal of the STOP cassette and the subsequent activation of the Notch1-intracellular domain. This allowed for the overexpression and expansion of Notch signaling in all endothelial cells. Male Tie2-Cre mice were mated with female ROSA26Notch mice and resulting embryos were dissected at embryonic day 9.5. To ablate Notch signaling, Tie2-Cre mice were used in a two generation cross to obtain Tie2-Cre; Rbpj flox/flox embryos. These embryos lack RBPJ binding activity in the endothelia. In both instances embryos were used for genotyping and the yolk sac were separated and used to isolate total RNA with an RNeasy mini kit. The RNA was analyzed with the Mouse Genome 430A Array from Affymetrix. Samples were performed in duplicate, and RNA from wild type yolk sac tissues was compared to activated Notch and RBPJ loss-of-function yolk sac tissues.
Project description:GW182 (Tnrc6a) is a key component of RISC (miRNA-Induced Silencing Complex) that plays a critical role in miRNA-mediated gene silencing. Here, we show that GW182 is expressed in the yolk sac endoderm, and that gene-trap disruption of GW182 leads to growth arrest of yolk sac endoderm, impaired hematopoiesis and embryonic lethality. To investigate roles of GW182 in the yolk sac endoderm, we assessed changes in mRNA expression in the yolk sac of E9.5 GW182gt/gt embryos using microarrays (Affymetrix).
Project description:PRDM6 belongs to the PRDM family of transcriptional repressors that all contain a PR domain and Zinc finger domains. Prdm6 has transcriptional repressor activity. Prdm6 may regulate factors that are involved in the differentiation / proliferation of smooth muscle cells, promoting proliferation. PRDM6 knockouts are embryonic lethal around 12.0 dpc knockout embryos eventually develop edema: cardiovascular defect vascularization defect in the yolk sac: dysorganized angiogenesis Keywords: cDNA array, yolk sac, murine embryo E10.5