Interplay between Netrin-1 and Norrin controls arteriovenous zonation of blood–retina barrier integrity
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ABSTRACT:
PROVIDER: PRJNA1190394 | ENA |
REPOSITORIES: ENA
Dataset's files
| Action | DRS | |||
|---|---|---|---|---|
| SRR31509069.fastq.gz | Fastqsanger.gz | |||
| SRR31509070.fastq.gz | Fastqsanger.gz | |||
| SRR31509071.fastq.gz | Fastqsanger.gz | |||
| SRR31509072.fastq.gz | Fastqsanger.gz | |||
| SRR31509073.fastq.gz | Fastqsanger.gz |
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Project description:The integrity of the blood–retina barrier (BRB) is crucial for phototransduction and vision, by tightly restricting transport of molecules between the blood and surrounding neuronal cells. Breakdown of the BRB leads to the development of retinal diseases. Here, we show that Netrin-1/Unc5b and Norrin/Lrp5 signaling establish a zonated endothelial cell gene expression program that controls BRB integrity. Using single-cell RNA sequencing (scRNA-seq) of postnatal BRB-competent mouse retina endothelial cells (ECs), we investigate >100 BRB genes encoding Wnt signaling components, tight junction proteins, and ion and nutrient transporters. We find that BRB gene expression is zonated across arteries, capillaries, and veins and regulated by opposing gradients of the Netrin-1 receptor Unc5b and Lrp5-β-catenin signaling between retinal arterioles and venules. Mice deficient for Ntn1 or Unc5b display more BRB leakage at the arterial end of the vasculature, while Lrp5 loss of function causes predominantly venular BRB leakage. ScRNA-seq of Ntn1 and Unc5b mutant ECs reveals down-regulated β-catenin signaling and BRB gene expression that is rescued by Ctnnb1 overactivation, along with BRB integrity. Mechanistically, we demonstrate that Netrin-1 and Norrin additively enhance β-catenin transcriptional activity and Lrp5 phosphorylation via the Discs large homologue 1 (Dlg1) scaffolding protein, and endothelial Lrp5-Unc5b function converges in protection of capillary BRB integrity. These findings explain how arteriovenous zonation is established and maintained in the BRB and reveal that BRB gene expression is regulated at the level of endothelial subtypes.
2024-12-03 | GSE282775 | GEO
Project description:The integrity of the blood-retina barrier (BRB) is crucial for phototransduction and vision, by tightly restricting transport of molecules between the blood and surrounding neuronal cells. Breakdown of the BRB leads to the development of retinal diseases. Here, we show that Netrin-1/Unc5b and Norrin/Lrp5 signaling establish a zonated endothelial cell gene expression program that controls BRB integrity. Using single-cell RNA sequencing (scRNA-seq) of postnatal BRB-competent mouse retina endothelial cells (ECs), we identify >100 BRB genes encoding Wnt signaling components, tight junction proteins, and ion and nutrient transporters. We find that BRB gene expression is zonated across arteries, capillaries, and veins and regulated by opposing gradients of the Netrin-1 receptor Unc5b and Lrp5-β-catenin signaling between retinal arterioles and venules. Mice deficient for Ntn1 or Unc5b display more BRB leakage at the arterial end of the vasculature, while Lrp5 loss of function causes predominantly venular BRB leakage. ScRNA-seq of Ntn1 and Unc5b mutant ECs reveals down-regulated β-catenin signaling and BRB gene expression that is rescued by Ctnnb1 overactivation, along with BRB integrity. Mechanistically, we demonstrate that Netrin-1 and Norrin additively enhance β-catenin transcriptional activity and Lrp5 phosphorylation via the Discs large homologue 1 (Dlg1) scaffolding protein, and endothelial Lrp5-Unc5b function converges in protection of capillary BRB integrity. These findings explain how arteriovenous zonation is established and maintained in the BRB and reveal that BRB gene expression is regulated at the level of endothelial subtypes.
| S-EPMC11670198 | biostudies-literature
Project description:Medulloblastoma (MB), a tumor of the cerebellum, is the most common malignant brain tumor in children. One third of all human MB exhibits a gene expression signature of Sonic hedgehog (Shh) signaling. Hedgehog (Hh) pathway inhibitors have shown efficacy in clinical trials for MB, however, tumors develop resistance to these compounds, highlighting the need to identify additional therapeutic targets for treatment. We have identified a role for Norrin signaling in tumor initiation in the Patched (Ptch) mouse model of MB. Norrin is a secreted factor that functions as an atypical Wnt by binding to the Frizzled4 (Fzd4) receptor on endothelial cells to activate canonical beta-catenin-mediated Wnt signaling pathway. In the cerebellum, activation of Norrin/Fzd4 signaling is required for the establishment and maintenance of the blood brain barrier (BBB). We have identified a role for Norrin signaling in the stroma as a potent tumor inhibitory signal. Inactivation of Norrin in Ptch+/- mice significantly shortens latency and increases MB incidence. This phenotype is associated with an increased frequency of pre-tumor lesions and their conversion to malignancy. In this context, loss of Norrin signalling in endothelial cells is associated with an accelerated transition to a pro-tumor stroma characterized by vascular permeability, inflammation and angiogenic remodelling. Accordingly, loss of Ndp significantly alters the stromal gene expression signature of established Ptch MB.
2016-10-12 | GSE81963 | GEO
Project description:Medulloblastoma (MB), a tumor of the cerebellum, is the most common malignant brain tumor in children. One third of all human MB exhibits a gene expression signature of Sonic hedgehog (Shh) signaling. Hedgehog (Hh) pathway inhibitors have shown efficacy in clinical trials for MB, however, tumors develop resistance to these compounds, highlighting the need to identify additional therapeutic targets for treatment. We have identified a role for Norrin signaling in tumor initiation in the Patched (Ptch) mouse model of MB. Norrin is a secreted factor that functions as an atypical Wnt by binding to the Frizzled4 (Fzd4) receptor on endothelial cells to activate canonical beta-catenin-mediated Wnt signaling pathway. In the cerebellum, activation of Norrin/Fzd4 signaling is required for the establishment and maintenance of the blood brain barrier (BBB). We have identified a role for Norrin signaling in the stroma as a potent tumor inhibitory signal. Inactivation of Norrin in Ptch+/- mice significantly shortens latency and increases MB incidence. This phenotype is associated with an increased frequency of pre-tumor lesions and their conversion to malignancy. In this context, loss of Norrin signalling in endothelial cells is associated with an accelerated transition to a pro-tumor stroma characterized by vascular permeability, inflammation and angiogenic remodelling. Accordingly, loss of Ndp significantly alters the stromal gene expression signature of established Ptch MB.
2016-10-12 | GSE81962 | GEO
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.
2009-10-01 | GSE16691 | GEO
Project description:Floor plate-derived extracellular signaling molecules, including canonical axon guidance cues of the Netrin family, control neuronal circuit organization. Despite the importance of the floor plate as an essential signaling centre in the developing vertebrate central nervous system, no systematic approach to identify binding partners for floor plate-expressed cellsurface and secreted proteins has been carried out. Here, we used a high-throughput assay to discover extracellular protein-protein interactions, which likely take place in the zebrafish floor plate microenvironment. The assembled floor plate network contains 47 interactions including the hitherto not reported interaction between Netrin-1 and Draxin. We further characterized this interaction, narrowed down the binding interface, and demonstrated that Draxin competes with Netrin receptors for binding to Netrin-1. Our results suggest that Draxin functions as an extracellular Netrin signaling modulator in vertebrates. A reciprocal gradient of Draxin might shape or sharpen the active Netrin gradient, thereby critically modulating its effect.
2015-05-31 | E-MTAB-3609 | biostudies-arrayexpress
Project description:The generation of induced pluripotent stem (iPS) cells holds great promise in regenerative medicine. However, the relative flaws in the understanding of the molecular mechanisms promoting or limiting reprogramming still hinder the efficient generation of high quality iPS cells. Whereas modulation of the initial Oct4, Sox2, Klf4 and c-Myc (OSKM) cocktail with new transcription factors has been extensively documented, comparatively little is known about soluble molecules promoting the process, even if such recombinant factors could be highly valuable for therapeutic applications. In this study we developed a large-scale identification method to uncover novel programmed cell death (PCD)-related mechanisms limiting somatic cell reprogramming to pluripotency (SCRP). We identified Netrin-1 and its dependence receptor Dcc (Deleted in Colorectal Carcinoma), previously described for their respective survival/death functions both in normal and oncogenic contexts, as novel key SCRP modulators. We show that the early phase of SCRP is accompanied with a strong Netrin-1 deficiency, due to the improper epigenetic regulation of the Ntn1 promoter by OSKM. Mechanistically, we demonstrate that such Netrin-1 imbalance induces apoptosis mediated by the dependence receptor Dcc in a p53-independent manner. Correction of the Netrin-1/Dcc equilibrium by gain-of-ligand and loss-of-receptor experiments constrains apoptosis and improves reprogramming. As a consequence, we propose a novel iPS derivation protocol including a sequential treatment with recombinant Netrin1 that greatly facilitates the generation of mouse and human iPS cells. RNA-sequencing of mouse embryonic fibroblasts (passage 2 and passage 4), mouse pre-iPS cells (passage 5 and passage 25), 1 clone of control iPS (passage 5 and passage 25) and 2 independent clones of "Netrin-1 derived" iPS cells (passage 5 and passage 25). For this analysis, mouse iPS cell lines were grown in KSR+LIF media.
2015-09-01 | E-GEOD-54107 | biostudies-arrayexpress
Project description:To characterize the long-term effect on the transcriptome of a decrement in Norrin/Fz4/Lrp signaling, microarray hybridization was performed with RNA from acutely dissociated and anti-PECAM immunoaffinity-purified adult WT, Fz4-/-, Lrp5-/-, and Norrin- retinal vascular cells.
2009-10-01 | GSE16703 | GEO
Project description:Interactions among neuroglial and vascular components are crucial for retinal angiogenesis and blood-retinal barrier (BRB) maturation. Neuronal synaptic dysfunctions precede vascular abnormalities in many retinal pathologies. However, whether neuronal activity, specifically glutamatergic activity, regulates retinal angiogenesis and BRB maturation remains unclear. Using in vivo genetic studies in mice, single-cell RNA-sequencing and functional validation, we found that deep plexus angiogenesis and paracellular BRB maturation are delayed in Vglut1-/- retinas, where neurons fail to release glutamate. In contrast, deep plexus angiogenesis and paracellular BRB maturation are accelerated in Gnat1-/- retinas, where constitutively depolarized rods release excess glutamate. Mechanistically, Norrin expression and endothelial Norrin/b-catenin signaling are downregulated in Vglut1-/- retinas, and upregulated in Gnat1-/- retinas. Pharmacological activation of endothelial Norrin/ b-catenin signaling in Vglut1-/- retinas rescued both deep plexus angiogenesis and paracellular BRB integrity. Thus, our findings demonstrate that glutamatergic neuronal activity regulates retinal angiogenesis and BRB maturation by modulating Norrin/b-catenin signaling.
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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.
2009-10-10 | E-GEOD-16691 | biostudies-arrayexpress