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Zhao R, Liu M, Dai E, Chen C, Lv L, Peng L, He Y, Li S, Yang M. Deciphering a crucial dimeric interface governing Norrin dimerization and the pathogenesis of familial exudative vitreoretinopathy. FASEB J 2024; 38:e23493. [PMID: 38363575 DOI: 10.1096/fj.202302387r] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2023] [Revised: 01/18/2024] [Accepted: 02/02/2024] [Indexed: 02/17/2024]
Abstract
Familial exudative vitreoretinopathy (FEVR) is a hereditary eye disease that could cause blindness. It has been established that Norrin forms dimers to activate β-catenin signaling, yet the core interface for Norrin dimerization and the precise mechanism by which Norrin dimerization contributes to the pathogenesis of FEVR remain elusive. Here, we report an NDP variant, c.265T>C (p.Phe89Leu), that interrupted β-catenin signaling by disrupting Norrin dimerization. Structural and functional analysis revealed that the Phe-89 of one Norrin monomer interacts with Pro-98, Ser-101, Arg-121, and Ile-123 of another, forming two core symmetrical dimerization interfaces that are pivotal for the formation of a "hand-by-arm" dimer. Intriguingly, we proved that one of the two core symmetrical interfaces is sufficient for dimerization and activation of β-catenin signaling, with a substantial contribution from the Phe-89/Pro-98 interaction. Further functional analysis revealed that the disruption of both dimeric interfaces eliminates potential binding sites for LRP5, which could be partially restored by over-expression of TSPAN12. In conclusion, our findings unveil a core dimerization interface that regulates Norrin/LRP5 interaction, highlighting the essential role of Norrin dimerization on β-catenin signaling and providing potential therapeutic avenues for the treatment of FEVR.
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Affiliation(s)
- Rulian Zhao
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Department of Medical Genetics, The Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention, Chinese Academy of Medical Sciences (No.2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Min Liu
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Department of Medical Genetics, The Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention, Chinese Academy of Medical Sciences (No.2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Erkuan Dai
- Department of Ophthalmology, Xin Hua Hospital Affiliated to Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Chen Chen
- Center for Natural Products Research, Chengdu Institute of Biology, Chinese Academy of Sciences, Chengdu, China
| | - Liting Lv
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Department of Medical Genetics, The Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention, Chinese Academy of Medical Sciences (No.2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Li Peng
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Department of Medical Genetics, The Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention, Chinese Academy of Medical Sciences (No.2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Yunqi He
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Department of Medical Genetics, The Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention, Chinese Academy of Medical Sciences (No.2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Shujin Li
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Department of Medical Genetics, The Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention, Chinese Academy of Medical Sciences (No.2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
| | - Mu Yang
- The Sichuan Provincial Key Laboratory for Human Disease Gene Study, The Department of Medical Genetics, The Department of Laboratory Medicine, Sichuan Academy of Medical Sciences & Sichuan Provincial People's Hospital, University of Electronic Science and Technology of China, Chengdu, China
- Research Unit for Blindness Prevention, Chinese Academy of Medical Sciences (No.2019RU026), Sichuan Academy of Medical Sciences and Sichuan Provincial People's Hospital, Chengdu, China
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Mansoor M, Coussa RG, Strampe MR, Larson SA, Russell JF. Xp11.3 microdeletion causing Norrie disease and X-linked Kabuki syndrome. Am J Ophthalmol Case Rep 2023; 29:101798. [PMID: 36703904 DOI: 10.1016/j.ajoc.2023.101798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2022] [Revised: 01/03/2023] [Accepted: 01/12/2023] [Indexed: 01/20/2023] Open
Abstract
Purpose To describe a novel case of Norrie disease and X-linked Kabuki syndrome caused by a microdeletion encompassing multiple genes on the X chromosome. Observations A 3-day-old boy born at full term had bilateral retrolental fibrovascular plaques. Surgery with lensectomy and vitrectomy revealed bilateral, closed funnel retinal detachments consistent with a clinical diagnosis of Norrie disease. In addition, the baby had congenital heart defects, hearing loss, and dysmorphic facies. His mother carried a clinical diagnosis of Kabuki syndrome. Genetic testing of the baby revealed an Xp11.3 microdeletion that included the NDP and KDM6A genes, confirming the baby had both Norrie disease and X-linked Kabuki syndrome. The mother was found via ultrawide-field fluorescein angiography to have asymptomatic peripheral retinal vascular anomalies, consistent with NDP-associated familial exudative vitreoretinopathy (FEVR). Conclusions and importance This is the first reported case of Norrie disease together with X-linked Kabuki syndrome. Contiguous gene deletions may explain some of the variable systemic involvement in Norrie disease.
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Dillinger AE, Tamm ER. Retinal Pigmented Epithelium-Derived Ectopic Norrin Does Not Promote Intraretinal Angiogenesis in Transgenic Mice. Adv Exp Med Biol 2023; 1415:241-248. [PMID: 37440040 DOI: 10.1007/978-3-031-27681-1_35] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/14/2023]
Abstract
Formation of intraretinal capillaries and inner blood-retinal barrier during development requires norrin, a ligand of the canonical wingless/integrated (Wnt)/β-catenin signaling pathway. Here we addressed the question whether retinal pigmented epithelium (RPE)-derived overexpression of norrin in transgenic mice rescues the vascular phenotype caused by norrin deficiency. To this end, we generated NdpKO/Rpe65-Norrin mice and analyzed the activation of β-catenin signaling, the development of intraretinal capillaries, and the expression of blood-retinal barrier marker molecules. RPE-derived norrin induced retinal β-catenin signaling but failed to rescue the vascular developmental defects and the breakdown of the blood-retinal barrier in norrin-deficient mice. Sites of ectopic norrin expression and the amounts of secreted transgenic protein are critical factors to enable the angiogenic properties of norrin.
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Affiliation(s)
- Andrea E Dillinger
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany.
| | - Ernst R Tamm
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany
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Nguyen H, Lee SJ, Li Y. Selective Activation of the Wnt-Signaling Pathway as a Novel Therapy for the Treatment of Diabetic Retinopathy and Other Retinal Vascular Diseases. Pharmaceutics 2022; 14. [PMID: 36432666 DOI: 10.3390/pharmaceutics14112476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2022] [Revised: 11/07/2022] [Accepted: 11/14/2022] [Indexed: 11/18/2022] Open
Abstract
Retinal ischemia, often associated with various disorders such as diabetic retinopathy (DR), retinal vein occlusion, glaucoma, optic neuropathies, stroke, and other retinopathies, is a major cause of visual impairment and blindness worldwide. As proper blood supply to the retina is critical to maintain its high metabolic demand, any impediment to blood flow can lead to a decrease in oxygen supply, resulting in retinal ischemia. In the pathogenesis of DR, including diabetic macular edema (DME), elevated blood glucose leads to blood-retina barrier (BRB) disruptions, vascular leakage, and capillary occlusion and dropouts, causing insufficient delivery of oxygen to the retina, and ultimately resulting in visual impairment. Other potential causes of DR include neuronal dysfunction in the absence of vascular defect, genetic, and environmental factors. The exact disease progression remains unclear and varies from patient to patient. Vascular leakage leading to edema clearly links to visual impairment and remains an important target for therapy. Despite recent advances in the treatment of DME and DR with anti-VEGFs, effective therapies with new mechanisms of action to address current treatment limitations regarding vessel regeneration and reperfusion of ischemic retinal areas are still needed. The Wnt signaling pathway plays a critical role in proper vascular development and maintenance in the retina, and thus provides a novel therapeutic approach for the treatment of diabetic and other retinopathies. In this review, we summarize the potential of this pathway to address treatment gaps with current therapies, its promise as a novel and potentially disease modifying therapy for patients with DR and opportunities in other retinal vascular diseases.
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Chidiac R, Abedin M, Macleod G, Yang A, Thibeault PE, Blazer LL, Adams JJ, Zhang L, Roehrich H, Jo H, Seshagiri S, Sidhu SS, Junge HJ, Angers S. A Norrin/Wnt surrogate antibody stimulates endothelial cell barrier function and rescues retinopathy. EMBO Mol Med 2021; 13:e13977. [PMID: 34105895 PMCID: PMC8261507 DOI: 10.15252/emmm.202113977] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2021] [Revised: 05/14/2021] [Accepted: 05/17/2021] [Indexed: 02/06/2023] Open
Abstract
The FZD4:LRP5:TSPAN12 receptor complex is activated by the secreted protein Norrin in retinal endothelial cells and leads to βcatenin-dependent formation of the blood-retina-barrier during development and its homeostasis in adults. Mutations disrupting Norrin signaling have been identified in several congenital diseases leading to hypovascularization of the retina and blindness. Here, we developed F4L5.13, a tetravalent antibody designed to induce FZD4 and LRP5 proximity in such a way as to trigger βcatenin signaling. Treatment of cultured endothelial cells with F4L5.13 rescued permeability induced by VEGF in part by promoting surface expression of junction proteins. Treatment of Tspan12-/- mice with F4L5.13 restored retinal angiogenesis and barrier function. F4L5.13 treatment also significantly normalized neovascularization in an oxygen-induced retinopathy model revealing a novel therapeutic strategy for diseases characterized by abnormal angiogenesis and/or barrier dysfunction.
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Affiliation(s)
- Rony Chidiac
- Leslie Dan Faculty of PharmacyUniversity of TorontoTorontoONCanada
| | - Md. Abedin
- Department of Ophthalmology and Visual NeurosciencesUniversity of MinnesotaMinneapolisMNUSA
| | - Graham Macleod
- Leslie Dan Faculty of PharmacyUniversity of TorontoTorontoONCanada
| | - Andy Yang
- Leslie Dan Faculty of PharmacyUniversity of TorontoTorontoONCanada
| | | | | | | | - Lingling Zhang
- Department of Ophthalmology and Visual NeurosciencesUniversity of MinnesotaMinneapolisMNUSA
| | - Heidi Roehrich
- Department of Ophthalmology and Visual NeurosciencesUniversity of MinnesotaMinneapolisMNUSA
| | - Ha‐Neul Jo
- Department of Ophthalmology and Visual NeurosciencesUniversity of MinnesotaMinneapolisMNUSA
| | | | - Sachdev S Sidhu
- AntlerA TherapeuticsFoster CityCAUSA
- Donnelly CentreUniversity of TorontoTorontoONCanada
- Department of Molecular GeneticsUniversity of TorontoTorontoONCanada
| | - Harald J Junge
- Department of Ophthalmology and Visual NeurosciencesUniversity of MinnesotaMinneapolisMNUSA
| | - Stephane Angers
- Leslie Dan Faculty of PharmacyUniversity of TorontoTorontoONCanada
- AntlerA TherapeuticsFoster CityCAUSA
- Department of BiochemistryUniversity of TorontoTorontoONCanada
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Zhou Y, Shapiro MJ, Burton BK, Mets MB, Kurup SP. Case report: A case of Norrie disease due to deletion of the entire coding region of NDP gene. Am J Ophthalmol Case Rep 2021; 23:101151. [PMID: 34189345 PMCID: PMC8220341 DOI: 10.1016/j.ajoc.2021.101151] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2020] [Revised: 04/07/2021] [Accepted: 06/14/2021] [Indexed: 10/24/2022] Open
Abstract
Purpose Norrie disease is a rare X-linked recessive vitreoretinopathy. Variants of the NDP gene are associated with this condition. This case reports aims to demonstrate the variations of clinical presentations and exam findings of this disease. Observations A retrospective chart review of the patient's ocular and systemic findings and imaging results was performed. The patient had received genetic testing, including mutational analysis of targeted genes associated with retrolental masses. The patient had a comprehensive eye exam for bilateral leukocoria, demonstrating large retrolental masses, anterior polar cataracts, stretched ciliary processes, and roving eye movements. B-scan ultrasonography and magnetic resonance imaging indicated total, funnel-shaped retinal detachments, which is a unique retinal configuration in Norrie disease. Genetic testing confirmed deletion of the coding region of all three exons in the NDP gene, which confirmed Norrie disease. He has not shown any extraocular involvement to date. Conclusions and Importance This is a case demonstrating the association between deletion of the coding region NDP gene and Norrie disease. The phenotypical variation of this disease warrants further studies of genotype-phenotype correlations and mutations of the NDP gene.
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Affiliation(s)
- Yujia Zhou
- Division of Ophthalmology, Ann & Robert H. Lurie Children's Hospital of Chicago, 225 E Chicago Ave, Chicago, IL, 60611, USA
| | - Michael J Shapiro
- Retina Consultants, Ltd., 2454 E Dempster St Ste 400, Des Plaines, IL, 60016, USA
| | - Barbara K Burton
- Division of Genetics, Birth Defects & Metabolism, Ann & Robert H. Lurie Children's Hospital of Chicago, 225 E Chicago Ave, Chicago, IL, 60611, USA.,Department of Pediatrics, Northwestern University Feinberg School of Medicine, 420 E Superior St, Chicago, IL, 60611, USA
| | - Marilyn B Mets
- Division of Ophthalmology, Ann & Robert H. Lurie Children's Hospital of Chicago, 225 E Chicago Ave, Chicago, IL, 60611, USA.,Department of Ophthalmology, Northwestern University Feinberg School of Medicine, 645 N Michigan Ave, Suite 440, Chicago, IL, 60611, USA
| | - Sudhi P Kurup
- Division of Ophthalmology, Ann & Robert H. Lurie Children's Hospital of Chicago, 225 E Chicago Ave, Chicago, IL, 60611, USA.,Department of Ophthalmology, Northwestern University Feinberg School of Medicine, 645 N Michigan Ave, Suite 440, Chicago, IL, 60611, USA
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7
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Abstract
The canonical Wnt/β-catenin signaling pathway has been shown to play a major role during embryonic development and maturation of the central nervous system including the retina. It has a significant impact on retinal vessel formation and maturation, as well as on the establishment of synaptic structures and neuronal function in the central nervous system. Mutations in components of the Wnt/β-catenin signaling cascade may lead to severe retinal diseases, while dysregulation of Wnt signaling can contribute to disease progression. Apart from the angiogenic role of Wnt/β-catenin signaling, research in the last decades leads to the theory of a protective effect of Wnt/β-catenin signaling on damaged neurons. In this review, we focus on the neuroprotective properties of the Wnt/β-catenin pathway as well as its downstream signaling in the retina.
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Affiliation(s)
- Stefan Kassumeh
- Department of Ophthalmology, University Hospital, LMU Munich, Mathildenstrasse 8, 80336 Munich, Germany
| | - Gregor R Weber
- Department of Ophthalmology, University Hospital, LMU Munich, Mathildenstrasse 8, 80336 Munich, Germany
| | - Matthias Nobl
- Department of Ophthalmology, University Hospital, LMU Munich, Mathildenstrasse 8, 80336 Munich, Germany
| | - Siegfried G Priglinger
- Department of Ophthalmology, University Hospital, LMU Munich, Mathildenstrasse 8, 80336 Munich, Germany
| | - Andreas Ohlmann
- Department of Ophthalmology, University Hospital, LMU Munich, Mathildenstrasse 8, 80336 Munich, Germany
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Kassumeh S, Leopold S, Fuchshofer R, Thomas CN, Priglinger SG, Tamm ER, Ohlmann A. Norrin Protects Retinal Ganglion Cells from Excitotoxic Damage via the Induction of Leukemia Inhibitory Factor. Cells 2020; 9:E277. [PMID: 31979254 DOI: 10.3390/cells9020277] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/25/2019] [Revised: 01/17/2020] [Accepted: 01/22/2020] [Indexed: 11/17/2022] Open
Abstract
PURPOSE To investigate whether and how leukemia inhibitory factor (Lif) is involved in mediating the neuroprotective effects of Norrin on retinal ganglion cells (RGC) following excitotoxic damage. Norrin is a secreted protein that protects RGC from N-methyl-d-aspartate (NMDA)-mediated excitotoxic damage, which is accompanied by increased expression of protective factors such as Lif, Edn2 and Fgf2. METHODS Lif-deficient mice were injected with NMDA in one eye and NMDA plus Norrin into the other eye. RGC damage was investigated and quantified by TUNEL labeling 24 h after injection. Retinal mRNA expression was analyzed by quantitative real-time polymerase chain reaction following retinal treatment. RESULTS After intravitreal injection of NMDA and Norrin in wild-type mice approximately 50% less TUNEL positive cells were observed in the RGC layer when compared to NMDA-treated littermates, an effect which was lost in Lif-deficient mice. The mRNA expression for Gfap, a marker for Müller cell gliosis, as well as Edn2 and Fgf2 was induced in wild-type mice following NMDA/Norrin treatment but substantially blocked in Lif-deficient mice. CONCLUSIONS Norrin mediates its protective properties on RGC via Lif, which is required to enhance Müller cell gliosis and to induce protective factors such as Edn2 or Fgf2.
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Bang I, Kim HR, Beaven AH, Kim J, Ko SB, Lee GR, Kan W, Lee H, Im W, Seok C, Chung KY, Choi HJ. Biophysical and functional characterization of Norrin signaling through Frizzled4. Proc Natl Acad Sci U S A 2018; 115:8787-92. [PMID: 30104375 DOI: 10.1073/pnas.1805901115] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Wnt signaling is initiated by Wnt ligand binding to the extracellular ligand binding domain, called the cysteine-rich domain (CRD), of a Frizzled (Fzd) receptor. Norrin, an atypical Fzd ligand, specifically interacts with Fzd4 to activate β-catenin-dependent canonical Wnt signaling. Much of the molecular basis that confers Norrin selectivity in binding to Fzd4 was revealed through the structural study of the Fzd4CRD-Norrin complex. However, how the ligand interaction, seemingly localized at the CRD, is transmitted across full-length Fzd4 to the cytoplasm remains largely unknown. Here, we show that a flexible linker domain, which connects the CRD to the transmembrane domain, plays an important role in Norrin signaling. The linker domain directly contributes to the high-affinity interaction between Fzd4 and Norrin as shown by ∼10-fold higher binding affinity of Fzd4CRD to Norrin in the presence of the linker. Swapping the Fzd4 linker with the Fzd5 linker resulted in the loss of Norrin signaling, suggesting the importance of the linker in ligand-specific cellular response. In addition, structural dynamics of Fzd4 associated with Norrin binding investigated by hydrogen/deuterium exchange MS revealed Norrin-induced conformational changes on the linker domain and the intracellular loop 3 (ICL3) region of Fzd4. Cell-based functional assays showed that linker deletion, L430A and L433A mutations at ICL3, and C-terminal tail truncation displayed reduced β-catenin-dependent signaling activity, indicating the functional significance of these sites. Together, our results provide functional and biochemical dissection of Fzd4 in Norrin signaling.
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Lai MB, Zhang C, Shi J, Johnson V, Khandan L, McVey J, Klymkowsky MW, Chen Z, Junge HJ. TSPAN12 Is a Norrin Co-receptor that Amplifies Frizzled4 Ligand Selectivity and Signaling. Cell Rep 2017; 19:2809-22. [PMID: 28658627 DOI: 10.1016/j.celrep.2017.06.004] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Revised: 03/29/2017] [Accepted: 05/27/2017] [Indexed: 11/23/2022] Open
Abstract
Accessory proteins in Frizzled (FZD) receptor complexes are thought to determine ligand selectivity and signaling amplitude. Genetic evidence indicates that specific combinations of accessory proteins and ligands mediate vascular β-catenin signaling in different CNS structures. In the retina, the tetraspanin TSPAN12 and the ligand norrin (NDP) mediate angiogenesis, and both genes are linked to familial exudative vitreoretinopathy (FEVR), yet the molecular function of TSPAN12 remains poorly understood. Here, we report that TSPAN12 is an essential component of the NDP receptor complex and interacts with FZD4 and NDP via its extracellular loops, consistent with an action as co-receptor that enhances FZD4 ligand selectivity for NDP. FEVR-linked mutations in TSPAN12 prevent the incorporation of TSPAN12 into the NDP receptor complex. In vitro and in Xenopus embryos, TSPAN12 alleviates defects of FZD4 M105V, a mutation that destabilizes the NDP/FZD4 interaction. This study sheds light on the poorly understood function of accessory proteins in FZD signaling.
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Yoon C, Song H, Yin T, Bausch-Fluck D, Frei AP, Kattman S, Dubois N, Witty AD, Hewel JA, Guo H, Emili A, Wollscheid B, Keller G, Zandstra PW. FZD4 Marks Lateral Plate Mesoderm and Signals with NORRIN to Increase Cardiomyocyte Induction from Pluripotent Stem Cell-Derived Cardiac Progenitors. Stem Cell Reports 2017; 10:87-100. [PMID: 29249665 PMCID: PMC5768897 DOI: 10.1016/j.stemcr.2017.11.008] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2017] [Revised: 11/13/2017] [Accepted: 11/14/2017] [Indexed: 01/14/2023] Open
Abstract
The identification of cell surface proteins on stem cells or stem cell derivatives is a key strategy for the functional characterization, isolation, and understanding of stem cell population dynamics. Here, using an integrated mass spectrometry- and microarray-based approach, we analyzed the surface proteome and transcriptome of cardiac progenitor cells (CPCs) generated from the stage-specific differentiation of mouse and human pluripotent stem cells. Through bioinformatics analysis, we have identified and characterized FZD4 as a marker for lateral plate mesoderm. Additionally, we utilized FZD4, in conjunction with FLK1 and PDGFRA, to further purify CPCs and increase cardiomyocyte (CM) enrichment in both mouse and human systems. Moreover, we have shown that NORRIN presented to FZD4 further increases CM output via proliferation through the canonical WNT pathway. Taken together, these findings demonstrate a role for FZD4 in mammalian cardiac development. Identified and characterized FZD4 as a new marker for lateral plate mesoderm FZD4, in conjunction with FLK1 and PDGFRA, increases cardiomyocyte enrichment FZD4 is expressed in the human system and shows enrichment in cardiomyocytes NORRIN addition shows increase in cardiomyocyte output from FZD4 progenitor cells
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Affiliation(s)
- Charles Yoon
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Hannah Song
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Ting Yin
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada
| | - Damaris Bausch-Fluck
- Institute of Molecular Systems Biology at the Department of Health Sciences and Technology, Zurich 8092, Switzerland
| | - Andreas P Frei
- Institute of Molecular Systems Biology at the Department of Health Sciences and Technology, Zurich 8092, Switzerland
| | - Steven Kattman
- McEwen Centre for Regenerative Medicine, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
| | - Nicole Dubois
- McEwen Centre for Regenerative Medicine, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
| | - Alec D Witty
- McEwen Centre for Regenerative Medicine, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
| | - Johannes A Hewel
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Hongbo Guo
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Andrew Emili
- Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Department of Molecular Genetics, University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Bernd Wollscheid
- Institute of Molecular Systems Biology at the Department of Health Sciences and Technology, Zurich 8092, Switzerland
| | - Gordon Keller
- McEwen Centre for Regenerative Medicine, University Health Network, Toronto, ON M5G 1L7, Canada; Department of Medical Biophysics, University of Toronto, Toronto, ON M5G 1L7, Canada; Princess Margaret Cancer Centre, Toronto, ON M5G 2M9, Canada
| | - Peter W Zandstra
- Institute of Biomaterials and Biomedical Engineering, University of Toronto, Toronto, ON M5S 3G9, Canada; Donnelly Centre for Cellular and Biomolecular Research, University of Toronto, Toronto, ON M5S 3E1, Canada; Centre for Commercialization of Regenerative Medicine, Toronto, ON M5G 1M1, Canada; Medicine by Design: A Canada First Research Excellence Fund Program, University of Toronto, Toronto, ON M5G 1M1, Canada.
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12
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Mazzoni J, Smith JR, Shahriar S, Cutforth T, Ceja B, Agalliu D. The Wnt Inhibitor Apcdd1 Coordinates Vascular Remodeling and Barrier Maturation of Retinal Blood Vessels. Neuron 2017; 96:1055-1069.e6. [PMID: 29154126 DOI: 10.1016/j.neuron.2017.10.025] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2017] [Revised: 07/03/2017] [Accepted: 10/19/2017] [Indexed: 12/20/2022]
Abstract
Coordinating angiogenesis with acquisition of tissue-specific properties in endothelial cells is essential for vascular function. In the retina, endothelial cells form a blood-retina barrier by virtue of tight junctions and low transcytosis. While the canonical Norrin/Fz4/Lrp5/6 pathway is essential for angiogenesis, vascular remodeling, and barrier maturation, how these diverse processes are coordinated remains poorly understood. Here we demonstrate that Apcdd1, a negative regulator of Wnt/β-catenin signaling, is expressed in retinal endothelial cells during angiogenesis and barrier formation. Apcdd1-deficient mice exhibit a transient increase in vessel density at ages P10-P12 due to delayed vessel pruning. Moreover, Apcdd1 mutant endothelial cells precociously form the paracellular component of the barrier. Conversely, mice that overexpress Apcdd1 in retina endothelial cells have reduced vessel density but increased paracellular barrier permeability. Apcdd1 thus serves to precisely modulate Wnt/Norrin signaling activity in the retinal endothelium and coordinate the timing of both vascular pruning and barrier maturation.
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Affiliation(s)
- Jenna Mazzoni
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA; Department of Developmental and Cell Biology, University of California, Irvine, CA 92697, USA
| | - Julian R Smith
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA
| | - Sanjid Shahriar
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA; Department of Pathology & Cell Biology, Columbia University Medical Center, New York, NY 10032, USA
| | - Tyler Cutforth
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA; Columbia Translational Neuroscience Initiative, Columbia University Medical Center, New York, NY 10032, USA
| | - Bernardo Ceja
- Department of Developmental and Cell Biology, University of California, Irvine, CA 92697, USA
| | - Dritan Agalliu
- Department of Neurology, Columbia University Medical Center, New York, NY 10032, USA; Department of Pathology & Cell Biology, Columbia University Medical Center, New York, NY 10032, USA; Department of Pharmacology, Columbia University Medical Center, New York, NY 10032, USA; Columbia Translational Neuroscience Initiative, Columbia University Medical Center, New York, NY 10032, USA.
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13
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Dailey WA, Drenser KA, Wong SC, Cheng M, Vercellone J, Roumayah KK, Feeney EV, Deshpande M, Guzman AE, Trese M, Mitton KP. Norrin treatment improves ganglion cell survival in an oxygen-induced retinopathy model of retinal ischemia. Exp Eye Res 2017; 164:129-138. [PMID: 28823941 DOI: 10.1016/j.exer.2017.08.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Revised: 07/17/2017] [Accepted: 08/14/2017] [Indexed: 12/25/2022]
Abstract
Treatment of a mouse model of oxygen-induced retinopathy (OIR) with recombinant human Norrin (Norrie Disease Protein, gene: NDP) accelerates regrowth of the microvasculature into central ischemic regions of the neural retina, which are generated after treatment with 75% oxygen. While this reduces the average duration and severity of ischemia overall, we do not know if this accelerated recovery of the microvasculature results in any significant survival of retinal ganglion cells (RGCs). The purpose of this study was to investigate ganglion cell survival with and without the intravitreal injection of Norrin in the murine model of oxygen induced retinopathy (OIR), using two strains of mice: C57BL/6J and Thy1-YFP mice. Intravitreal injections of Norrin or vehicle were done after five days of exposure to 75% oxygen from ages P7 to P12. The C57BL/J mice were followed by Spectral-Domain Optical Coherence Tomography (SD-OCT), and the average nerve fiber layer (NFL) and inner-plexiform layer (IPL) thicknesses were measured at twenty-four locations per retina at P42. Additionally, some C57BL/J retinas were flat mounted and immunostained for the RGC marker, Brn3a, to compare the population density of surviving retinal ganglion cells. Using homozygous Thy1-YFP mice, single intrinsically fluorescent RGCs were imaged in live animals with a Micron-III imaging system at ages P21, 28 and P42. The relative percentage of YFP-fluorescent RGCs with dendritic arbors were compared. At age P42, the NFL was thicker in Norrin-injected OIR eyes, 14.4 μm, compared to Vehicle-injected OIR eyes, 13.3 μm (p = 0.01). In the superior retina, the average thickness of the IPL was greater in Norrin-injected OIR eyes, 37.7 μm, compared to Vehicle-injected OIR eyes, 34.6 μm (p = 0.04). Retinas from Norrin injected OIR mice had significantly more surviving RGCs (p = 0.03) than vehicle-injected mice. Based upon NFL thickness and counts of RGCs, we conclude that Norrin treatment, early in the ischemic phase, increased the relative population density of surviving RGCs in the central retinas of OIR mice.
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Affiliation(s)
- Wendy A Dailey
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States
| | - Kimberly A Drenser
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States; Associated Retinal Consultants, Novi, MI, United States
| | - Sui Chien Wong
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States
| | - Mei Cheng
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States
| | - Joseph Vercellone
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States
| | - Kevin K Roumayah
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States
| | - Erin V Feeney
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States
| | - Mrinalini Deshpande
- Control of Gene Expression Laboratory, Eye Research Institute, Oakland University, United States
| | - Alvaro E Guzman
- Control of Gene Expression Laboratory, Eye Research Institute, Oakland University, United States
| | - Michael Trese
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States; Associated Retinal Consultants, Novi, MI, United States
| | - Kenneth P Mitton
- Pediatric Retinal Research Laboratory, Eye Research Institute, Oakland University, Rochester Hills, MI 48309, United States; Control of Gene Expression Laboratory, Eye Research Institute, Oakland University, United States.
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14
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Bassett EA, Tokarew N, Allemano EA, Mazerolle C, Morin K, Mears AJ, McNeill B, Ringuette R, Campbell C, Smiley S, Pokrajac NT, Dubuc AM, Ramaswamy V, Northcott PA, Remke M, Monnier PP, Potter D, Paes K, Kirkpatrick LL, Coker KJ, Rice DS, Perez-Iratxeta C, Taylor MD, Wallace VA. Norrin/Frizzled4 signalling in the preneoplastic niche blocks medulloblastoma initiation. eLife 2016; 5. [PMID: 27823583 PMCID: PMC5100999 DOI: 10.7554/elife.16764] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2016] [Accepted: 10/07/2016] [Indexed: 12/25/2022] Open
Abstract
The tumor microenvironment is a critical modulator of carcinogenesis; however, in many tumor types, the influence of the stroma during preneoplastic stages is unknown. Here we explored the relationship between pre-tumor cells and their surrounding stroma in malignant progression of the cerebellar tumor medulloblastoma (MB). We show that activation of the vascular regulatory signalling axis mediated by Norrin (an atypical Wnt)/Frizzled4 (Fzd4) inhibits MB initiation in the Ptch+/− mouse model. Loss of Norrin/Fzd4-mediated signalling in endothelial cells, either genetically or by short-term blockade, increases the frequency of pre-tumor lesions and creates a tumor-permissive microenvironment at the earliest, preneoplastic stages of MB. This pro-tumor stroma, characterized by angiogenic remodelling, is associated with an accelerated transition from preneoplasia to malignancy. These data expose a stromal component that regulates the earliest stages of tumorigenesis in the cerebellum, and a novel role for the Norrin/Fzd4 axis as an endogenous anti-tumor signal in the preneoplastic niche. DOI:http://dx.doi.org/10.7554/eLife.16764.001
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Affiliation(s)
- Erin A Bassett
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Nicholas Tokarew
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada
| | - Ema A Allemano
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Chantal Mazerolle
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Katy Morin
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Alan J Mears
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Brian McNeill
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Randy Ringuette
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Charles Campbell
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Sheila Smiley
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada
| | - Neno T Pokrajac
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.,Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, Canada
| | - Adrian M Dubuc
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.,Developmental and Stem Cell Biology Program, Arthur and Sonia Labatt Brain Tumor Research Centre, The Hospital for Sick Children, Toronto, Canada
| | - Vijay Ramaswamy
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.,Developmental and Stem Cell Biology Program, Arthur and Sonia Labatt Brain Tumor Research Centre, The Hospital for Sick Children, Toronto, Canada.,Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada.,Division of Haematology/Oncology, The Hospital for Sick Children, Toronto, Canada
| | - Paul A Northcott
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.,Developmental and Stem Cell Biology Program, Arthur and Sonia Labatt Brain Tumor Research Centre, The Hospital for Sick Children, Toronto, Canada
| | - Marc Remke
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.,Developmental and Stem Cell Biology Program, Arthur and Sonia Labatt Brain Tumor Research Centre, The Hospital for Sick Children, Toronto, Canada
| | - Philippe P Monnier
- Genetics and Development Division, Krembil Research Institute, University Health Network, Toronto, Canada.,Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
| | - David Potter
- Department of Ophthalmology, Lexicon Pharmaceuticals Inc., The Woodlands, United States
| | - Kim Paes
- Department of Ophthalmology, Lexicon Pharmaceuticals Inc., The Woodlands, United States
| | - Laura L Kirkpatrick
- Department of Ophthalmology, Lexicon Pharmaceuticals Inc., The Woodlands, United States
| | - Kenneth J Coker
- Department of Ophthalmology, Lexicon Pharmaceuticals Inc., The Woodlands, United States
| | - Dennis S Rice
- Department of Ophthalmology, Lexicon Pharmaceuticals Inc., The Woodlands, United States
| | - Carol Perez-Iratxeta
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada.,Department of Cellular and Molecular Medicine, University of Ottawa, Ottawa, Canada
| | - Michael D Taylor
- Department of Laboratory Medicine and Pathobiology, University of Toronto, Toronto, Canada.,Developmental and Stem Cell Biology Program, Arthur and Sonia Labatt Brain Tumor Research Centre, The Hospital for Sick Children, Toronto, Canada.,Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada
| | - Valerie A Wallace
- Regenerative Medicine Program, Ottawa Hospital Research Institute, Ottawa, Canada.,Department of Biochemistry, Microbiology and Immunology, University of Ottawa, Ottawa, Canada.,Donald K. Johnson Eye Institute, Krembil Research Institute, University Health Network, Toronto, Canada.,Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Canada
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15
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Bertalovitz AC, Pau MS, Gao S, Malbon CC, Wang HY. Frizzled-4 C-terminus Distal to KTXXXW Motif is Essential for Normal Dishevelled Recruitment and Norrin-stimulated Activation of Lef/Tcf-dependent Transcriptional Activation. J Mol Signal 2016; 11:1. [PMID: 27096005 DOI: 10.5334/1750-2187-11-1] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The carboxy (C)-termini of G protein coupled receptors (GPCR) dictate essential functions. The KTXXXW motif C-terminus of Frizzleds (FZD) has been implicated in recruitment of Dishevelled (DVL). Through study of FZD4 and its associated ligand Norrin, we report that a minimum of three residues distal to the KTXXXW motif in the C-terminal tail of Frizzled-4 are essential for DVL recruitment and robust Lef/Tcf-dependent transcriptional activation in response to Norrin.
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16
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Zeilbeck LF, Müller BB, Leopold SA, Senturk B, Langmann T, Tamm ER, Ohlmann A. Norrin mediates angiogenic properties via the induction of insulin-like growth factor-1. Exp Eye Res 2015; 145:317-326. [PMID: 26706283 DOI: 10.1016/j.exer.2015.12.001] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2015] [Revised: 09/29/2015] [Accepted: 12/01/2015] [Indexed: 12/21/2022]
Abstract
Norrin is an angiogenic signaling molecule that activates canonical Wnt/β-catenin signaling, and is involved in capillary formation in retina and brain. Moreover, Norrin induces vascular repair following an oxygen-induced retinopathy (OIR), the model of retinopathy of prematurity in mice. Since insulin-like growth factor (IGF)-1 is a very potent angiogenic molecule, we investigated if IGF-1 is a downstream mediator of Norrin's angiogenic properties. In retinae of transgenic mice with an ocular overexpression of Norrin (βB1-Norrin), we found at postnatal day (P)11 a significant increase of IGF-1 mRNA compared to wild-type littermates. In addition, after treatment of cultured Müller cells or dermal microvascular endothelial cells with Norrin we observed an increase of IGF-1 and its mRNA, an effect that could be blocked with DKK-1, an inhibitor of Wnt/β-catenin signaling. When OIR was induced, the expression of IGF-1 was significantly suppressed in both transgenic βB1-Norrin mice and wild-type littermates when compared to wild-type animals that were housed in room air. Furthermore, at P13, one day after the mice had returned to normoxic conditions, IGF-1 levels were significantly higher in transgenic mice compared to wild-type littermates. Finally, after intravitreal injections of inhibitory α-IGF-1 antibodies at P12 or at P12 and P14, the Norrin-mediated vascular repair was significantly attenuated. We conclude that Norrin induces the expression of IGF-1 via an activation of the Wnt/β-catenin signaling pathway, an effect that significantly contributes to the protective effects of Norrin against an OIR.
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Affiliation(s)
- Ludwig F Zeilbeck
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany
| | - Birgit B Müller
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany
| | - Stephanie A Leopold
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany
| | - Berna Senturk
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany
| | - Thomas Langmann
- Laboratory for Experimental Immunology of the Eye, Department of Ophthalmology, University of Cologne, Cologne, Germany
| | - Ernst R Tamm
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany
| | - Andreas Ohlmann
- Institute of Human Anatomy and Embryology, University of Regensburg, Regensburg, Germany.
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17
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Pau MS, Gao S, Malbon CC, Wang HY, Bertalovitz AC. The Intracellular Loop 2 F328S Frizzled-4 Mutation Implicated in Familial Exudative Vitreoretinopathy Impairs Dishevelled Recruitment. J Mol Signal 2015; 10:5. [PMID: 27096003 DOI: 10.5334/1750-2187-10-6] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/01/2022] Open
Abstract
Familial exudative vitreoretinopathy (FEVR) is a disease state characterized by aberrant retinal angiogenesis. Norrin-induced activation of Frizzled-4 (Fz4) has a major role in regulating beta-catenin levels in the eye that, in turn, modulate the blood retina barrier (BRB). Here we gain insight on the basis of the pathology of a FEVR implicated F328S Fz4 mutant by study. The receptor exhibits a substantially reduced ability to activate Lef/Tcf-dependent transcription. This impaired activation correlates with a decreased ability to stabilize and recruit Dishevelled-2 (Dvl2) to the cell surface. Aromaticity at position 328 of the intracellular loop 2 (iloop2) is revealed similarly as a prerequisite for Dvl2 recruitment to the Fz4. This aromaticity at 328 enables normal Norrin-induced canonical activation. The corresponding position in iloop2 of other Frizzleds likely functions in Dvl recruitment.
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18
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Zhu L, Shen W, Lyons B, Wang Y, Zhou F, Gillies MC. Dysregulation of inter-photoreceptor retinoid-binding protein (IRBP) after induced Müller cell disruption. J Neurochem 2015; 133:909-18. [PMID: 25692504 DOI: 10.1111/jnc.13075] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2014] [Revised: 02/11/2015] [Accepted: 02/12/2015] [Indexed: 11/29/2022]
Abstract
Reduced expression of a ~150 kDa protein was unexpectedly observed while investigating Norrin protein in a transgenic murine model in which Müller cells can be selectively and inducibly disrupted. Isolation of this unknown protein via ion exchange and hydrophobic interaction chromatography followed by Tandem mass spectrometry identified it as Inter-photoreceptor retinoid-binding protein (IRBP). Significantly reduced IRBP mRNA expression was observed at the early and late stages after Müller cell disruption. IRBP protein expression was also consistently reduced to 5.7% of the control level as early as 1 week after Müller cell disruption. This down-regulation of IRBP was accompanied by focal hyperfluorescent dots and cytotoxic N-retinylidene-N-retinylethanolamine (A2E) accumulation. In vitro treatment of cone photoreceptor cell lines with conditioned medium collected from stressed Müller cells suggested that Müller cells regulated photoreceptors expression of IRBP via secreted factor(s). In vivo studies suggested that one of these secreted factors was tumour necrosis factor alpha (TNFα). These findings suggest that dysregulation of IRBP expression caused by Müller cell dysfunction may be an important early event in photoreceptor degeneration in some retinal diseases. This study reports down-regulation of inter-photoreceptor retinoid-binding protein (IRBP) in photoreceptors and retinoid cycle derangement after Müller cell disruption in a transgenic mouse model. The findings indicate that Müller cells communicate with photoreceptors in response to stress by secreting soluble protein factor(s). We propose that down-regulation of IRBP may represent an early and novel pathogenic mechanism in degenerative retinal diseases.
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Affiliation(s)
- Ling Zhu
- Save Sight Institute, the University of Sydney, Sydney, NSW, Australia
| | - Weiyong Shen
- Save Sight Institute, the University of Sydney, Sydney, NSW, Australia
| | - Brian Lyons
- Save Sight Institute, the University of Sydney, Sydney, NSW, Australia
| | - Ying Wang
- Save Sight Institute, the University of Sydney, Sydney, NSW, Australia
| | - Fanfan Zhou
- Faculty of Pharmacy, the University of Sydney, Sydney, NSW, Australia
| | - Mark C Gillies
- Save Sight Institute, the University of Sydney, Sydney, NSW, Australia
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19
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Chen Y, Zhang Y, Tang J, Liu F, Hu Q, Luo C, Tang J, Feng H, Zhang JH. Norrin protected blood-brain barrier via frizzled-4/β-catenin pathway after subarachnoid hemorrhage in rats. Stroke 2014; 46:529-36. [PMID: 25550365 DOI: 10.1161/strokeaha.114.007265] [Citation(s) in RCA: 77] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/24/2023]
Abstract
BACKGROUND AND PURPOSE Norrin and its receptor Frizzled-4 have important roles in the blood-brain barrier development. This study is to investigate a potential role and mechanism of Norrin/Frizzled-4 on protecting blood-brain barrier integrity after subarachnoid hemorrhage (SAH). METHODS One hundred and seventy-eight male Sprague-Dawley rats were used. SAH model was induced by endovascular perforation. Frizzled-4 small interfering RNA was injected intracerebroventricularly 48 hours before SAH. Norrin was administrated intracerebroventricularly 3 hours after SAH. SAH grade, neurological scores, brain water content, Evans blue extravasation, western blots, and immunofluorescence were used to study the mechanisms of Norrin and its receptor regulation protein TSPAN12, as well as neurological outcome. RESULTS Endogenous Norrin and TSPAN12 expression were increased after SAH, and Norrin was colocalized with astrocytes marker glial fibrillary acidic protein in cortex. Exogenous Norrin treatment significantly alleviated neurobehavioral dysfunction, reduced brain water content and Evans blue extravasation, promoted β-catenin nuclear translocation, and increased Occludin, VE-Cadherin, and ZO-1 expressions. These effects were abolished by Frizzled-4 small interfering RNA pretreated before SAH. CONCLUSIONS Norrin protected blood-brain barrier integrity and improved neurological outcome after SAH, and the action of Norrin appeared mediated by Frizzled-4 receptor activation, which promoted β-catenin nuclear translocation, which then enhanced Occludin, VE-Cadherin, and ZO-1 expression. Norrin might have potential to protect blood-brain barrier after SAH.
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Affiliation(s)
- Yujie Chen
- From the Departments of Neurosurgery (Y.C., H.F.) and Neurology (C.L.), Southwest Hospital, Third Military Medical University, Chongqing, China; and Department of Physiology and Pharmacology, Loma Linda University, CA (Y.C., Y.Z., J.T., F.L., Q.H., J.T., J.H.Z.)
| | - Yang Zhang
- From the Departments of Neurosurgery (Y.C., H.F.) and Neurology (C.L.), Southwest Hospital, Third Military Medical University, Chongqing, China; and Department of Physiology and Pharmacology, Loma Linda University, CA (Y.C., Y.Z., J.T., F.L., Q.H., J.T., J.H.Z.)
| | - Junjia Tang
- From the Departments of Neurosurgery (Y.C., H.F.) and Neurology (C.L.), Southwest Hospital, Third Military Medical University, Chongqing, China; and Department of Physiology and Pharmacology, Loma Linda University, CA (Y.C., Y.Z., J.T., F.L., Q.H., J.T., J.H.Z.)
| | - Fei Liu
- From the Departments of Neurosurgery (Y.C., H.F.) and Neurology (C.L.), Southwest Hospital, Third Military Medical University, Chongqing, China; and Department of Physiology and Pharmacology, Loma Linda University, CA (Y.C., Y.Z., J.T., F.L., Q.H., J.T., J.H.Z.)
| | - Qin Hu
- From the Departments of Neurosurgery (Y.C., H.F.) and Neurology (C.L.), Southwest Hospital, Third Military Medical University, Chongqing, China; and Department of Physiology and Pharmacology, Loma Linda University, CA (Y.C., Y.Z., J.T., F.L., Q.H., J.T., J.H.Z.)
| | - Chunxia Luo
- From the Departments of Neurosurgery (Y.C., H.F.) and Neurology (C.L.), Southwest Hospital, Third Military Medical University, Chongqing, China; and Department of Physiology and Pharmacology, Loma Linda University, CA (Y.C., Y.Z., J.T., F.L., Q.H., J.T., J.H.Z.)
| | - Jiping Tang
- From the Departments of Neurosurgery (Y.C., H.F.) and Neurology (C.L.), Southwest Hospital, Third Military Medical University, Chongqing, China; and Department of Physiology and Pharmacology, Loma Linda University, CA (Y.C., Y.Z., J.T., F.L., Q.H., J.T., J.H.Z.)
| | - Hua Feng
- From the Departments of Neurosurgery (Y.C., H.F.) and Neurology (C.L.), Southwest Hospital, Third Military Medical University, Chongqing, China; and Department of Physiology and Pharmacology, Loma Linda University, CA (Y.C., Y.Z., J.T., F.L., Q.H., J.T., J.H.Z.)
| | - John H Zhang
- From the Departments of Neurosurgery (Y.C., H.F.) and Neurology (C.L.), Southwest Hospital, Third Military Medical University, Chongqing, China; and Department of Physiology and Pharmacology, Loma Linda University, CA (Y.C., Y.Z., J.T., F.L., Q.H., J.T., J.H.Z.).
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20
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Abstract
Mammalian LGR4, 5 and 6 are seven-transmembrane receptors that are important for diverse physiological processes. These receptors are orthologous to DLGR2, a Drosophila receptor activated by the burs/pburs heterodimer important for morphogenesis. Although recent studies indicated that four R-spondin proteins are cognate ligands for LGR4, 5 and 6 receptors, several BMP antagonists in vertebrates have been postulated to be orthologous to burs and pburs. Using newly available genome sequences, we showed that norrin is a vertebrate ortholog for insect burs and pburs and stimulates Wnt signaling mediated by LGR4, but not by LGR5 and 6, in mammalian cells. Although norrin could only activate LGR4, binding studies suggested interactions between norrin and LGR4, 5 and 6. Norrin, the Norrie disease gene product, is also capable of activating Wnt signaling mediated by the Frizzled4 receptor and serves as a BMP antagonist. Mutagenesis studies indicated that different norrin mutations found in patients with Norrie disease can be categorized into subgroups according to defects for signaling through the three distinct binding proteins. Thus, norrin is a rare ligand capable of binding three receptors/binding proteins that are important for BMP and Wnt signaling pathways.
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Affiliation(s)
- Cheng Deng
- Program of Reproductive and Stem Cell Biology, Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, CA 94305-5317, USA
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