Abstract
Aberrant neovascularization contributes to diseases such as cancer, blindness and atherosclerosis, and is the consequence of inappropriate angiogenic signalling. Although many regulators of pathogenic angiogenesis have been identified, our understanding of this process is incomplete. Here we explore the transcriptome of retinal microvessels isolated from mouse models of retinal disease that exhibit vascular pathology, and uncover an upregulated gene, leucine-rich alpha-2-glycoprotein 1 (Lrg1), of previously unknown function. We show that in the presence of transforming growth factor-β1 (TGF-β1), LRG1 is mitogenic to endothelial cells and promotes angiogenesis. Mice lacking Lrg1 develop a mild retinal vascular phenotype but exhibit a significant reduction in pathological ocular angiogenesis. LRG1 binds directly to the TGF-β accessory receptor endoglin, which, in the presence of TGF-β1, results in promotion of the pro-angiogenic Smad1/5/8 signalling pathway. LRG1 antibody blockade inhibits this switch and attenuates angiogenesis. These studies reveal a new regulator of angiogenesis that mediates its effect by modulating TGF-β signalling.
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References
Leung, D. W., Cachianes, G., Kuang, W. J., Goeddel, D. V. & Ferrara, N. Vascular endothelial growth factor is a secreted angiogenic mitogen. Science 246, 1306–1309 (1989)
Carmeliet, P. et al. Abnormal blood vessel development and lethality in embryos lacking a single VEGF allele. Nature 380, 435–439 (1996)
Ferrara, N. et al. Heterozygous embryonic lethality induced by targeted inactivation of the VEGF gene. Nature 380, 439–442 (1996)
Holderfield, M. T. & Hughes, C. C. Crosstalk between vascular endothelial growth factor, notch, and transforming growth factor-β in vascular morphogenesis. Circ. Res. 102, 637–652 (2008)
Chung, A. S. & Ferrara, N. Developmental and pathological angiogenesis. Annu. Rev. Cell Dev. Biol. 27, 563–584 (2011)
Carmeliet, P. & Jain, R. K. Molecular mechanisms and clinical applications of angiogenesis. Nature 473, 298–307 (2011)
Pardali, E., Goumans, M. J. & ten Dijke, P. Signaling by members of the TGF-β family in vascular morphogenesis and disease. Trends Cell Biol. 20, 556–567 (2010)
Goumans, M. J., Liu, Z. & ten Dijke, P. TGF-β signaling in vascular biology and dysfunction. Cell Res. 19, 116–127 (2009)
Cunha, S. I. et al. Genetic and pharmacological targeting of activin receptor-like kinase 1 impairs tumor growth and angiogenesis. J. Exp. Med. 207, 85–100 (2010)
Cunha, S. I. & Pietras, K. ALK1 as an emerging target for antiangiogenic therapy of cancer. Blood 117, 6999–7006 (2011)
ten Dijke, P. & Arthur, H. M. Extracellular control of TGFβ signalling in vascular development and disease. Nature Rev. Mol. Cell Biol. 8, 857–869 (2007)
Xu, Q. et al. Vascular development in the retina and inner ear: control by Norrin and Frizzled-4, a high-affinity ligand-receptor pair. Cell 116, 883–895 (2004)
Ye, X. et al. Norrin, Frizzled-4, and Lrp5 signaling in endothelial cells controls a genetic program for retinal vascularization. Cell 139, 285–298 (2009)
Hackett, S. F., Wiegand, S., Yancopoulos, G. & Campochiaro, P. A. Angiopoietin-2 plays an important role in retinal angiogenesis. J. Cell. Physiol. 192, 182–187 (2002)
Haigh, J. J. et al. Cortical and retinal defects caused by dosage-dependent reductions in VEGF-A paracrine signaling. Dev. Biol. 262, 225–241 (2003)
Zhao, J., Sastry, S. M., Sperduto, R. D., Chew, E. Y. & Remaley, N. A. Arteriovenous crossing patterns in branch retinal vein occlusion. The Eye Disease Case-Control Study Group. Ophthalmology 100, 423–428 (1993)
Kumar, B. et al. The distribution of angioarchitectural changes within the vicinity of the arteriovenous crossing in branch retinal vein occlusion. Ophthalmology 105, 424–427 (1998)
Rakic, J. M. et al. Placental growth factor, a member of the VEGF family, contributes to the development of choroidal neovascularization. Invest. Ophthalmol. Vis. Sci. 44, 3186–3193 (2003)
Takeda, A. et al. CCR3 is a target for age-related macular degeneration diagnosis and therapy. Nature 460, 225–230 (2009)
Van de Veire, S. et al. Further pharmacological and genetic evidence for the efficacy of PIGF inhibition in cancer and eye disease. Cell 141, 178–190 (2010)
Sun, D., Kar, S. & Carr, B. I. Differentially expressed genes in TGF-β1 sensitive and resistant human hepatoma cells. Cancer Lett. 89, 73–79 (1995)
Li, X., Miyajima, M., Jiang, C. & Arai, H. Expression of TGF-βs and TGF-β type II receptor in cerebrospinal fluid of patients with idiopathic normal pressure hydrocephalus. Neurosci. Lett. 413, 141–144 (2007)
Saito, K. et al. Gene expression profiling of mucosal addressin cell adhesion molecule-1+ high endothelial venule cells (HEV) and identification of a leucine-rich HEV glycoprotein as a HEV marker. J. Immunol. 168, 1050–1059 (2002)
Spirin, K. S. et al. Basement membrane and growth factor gene expression in normal and diabetic human retinas. Curr. Eye Res. 18, 490–499 (1999)
Gao, B. B., Chen, X., Timothy, N., Aiello, L. P. & Feener, E. P. Characterization of the vitreous proteome in diabetes without diabetic retinopathy and diabetes with proliferative diabetic retinopathy. J. Proteome Res. 7, 2516–2525 (2008)
Lebrin, F. et al. Endoglin promotes endothelial cell proliferation and TGF-β/ALK1 signal transduction. EMBO J. 23, 4018–4028 (2004)
Anderberg, C. et al. Deficiency for endoglin in tumor vasculature weakens the endothelial barrier to metastatic dissemination. J. Exp. Med. 210, 563–579 (2013)
Mahmoud, M. et al. Pathogenesis of arteriovenous malformations in the absence of endoglin. Circ. Res. 106, 1425–1433 (2010)
Bobik, A. Transforming growth factor-betas and vascular disorders. Arterioscler. Thromb. Vasc. Biol. 26, 1712–1720 (2006)
ten Dijke, P., Goumans, M. J. & Pardali, E. Endoglin in angiogenesis and vascular diseases. Angiogenesis 11, 79–89 (2008)
Ray, B. N., Lee, N. Y., How, T. & Blobe, G. C. ALK5 phosphorylation of the endoglin cytoplasmic domain regulates Smad1/5/8 signaling and endothelial cell migration. Carcinogenesis 31, 435–441 (2010)
Lynch, J. et al. MiRNA-335 suppresses neuroblastoma cell invasiveness by direct targeting of multiple genes from the non-canonical TGF-β signalling pathway. Carcinogenesis 33, 976–985 (2012)
Gregory, A. D., Capoccia, B. J., Woloszynek, J. R. & Link, D. C. Systemic levels of G-CSF and interleukin-6 determine the angiogenic potential of bone marrow resident monocytes. J. Leukoc. Biol. 88, 123–131 (2010)
Blanks, J. C. & Johnson, L. V. Vascular atrophy in the retinal degenerative rd mouse. J. Comp. Neurol. 254, 543–553 (1986)
Heckenlively, J. R. et al. Mouse model of subretinal neovascularization with choroidal anastomosis. Retina 23, 518–522 (2003)
McKenzie, J. A. et al. Apelin is required for non-neovascular remodelling in the retina. Am. J. Pathol. 108, 399–409 (2012)
Fruttiger, M. Development of the mouse retinal vasculature: angiogenesis versus vasculogenesis. Invest. Ophthalmol. Vis. Sci. 43, 522–527 (2002)
Abbott, N. J., Hughes, C. C., Revest, P. A. & Greenwood, J. Development and characterisation of a rat brain capillary endothelial culture: towards an in vitro blood–brain barrier. J. Cell Sci. 103, 23–37 (1992)
Romero, I. A. et al. Changes in cytoskeletal and tight junctional proteins correlate with decreased permeability induced by dexamethasone in cultured rat brain endothelial cells. Neurosci. Lett. 344, 112–116 (2003)
Arnaoutova, I. & Kleinman, H. K. In vitro angiogenesis: endothelial cell tube formation on gelled basement membrane extract. Nature Protocols 5, 628–635 (2010)
Deckers, M. et al. Effect of angiogenic and antiangiogenic compounds on the outgrowth of capillary structures from fetal mouse bone explants. Lab. Invest. 81, 5–15 (2001)
Nicosia, R. F. & Ottinetti, A. Growth of microvessels in serum-free matrix culture of rat aorta. A quantitative assay of angiogenesis in vitro. Lab. Invest. 63, 115–122 (1990)
Balaggan, K. S. et al. EIAV vector-mediated delivery of endostatin or angiostatin inhibits angiogenesis and vascular hyperpermeability in experimental CNV. Gene Ther. 13, 1153–1165 (2006)
Toma, H. S., Barnett, J. M., Penn, J. S. & Kim, S. J. Improved assessment of laser-induced choroidal neovascularization. Microvasc. Res. 80, 295–302 (2010)
Smith, L. E. et al. Oxygen-induced retinopathy in the mouse. Invest. Ophthalmol. Vis. Sci. 35, 101–111 (1994)
Connor, K. M. et al. Quantification of oxygen-induced retinopathy in the mouse: a model of vessel loss, vessel regrowth and pathological angiogenesis. Nature Protocols 4, 1565–1573 (2009)
Acknowledgements
This project was supported by grants from the Lowy Medical Research Foundation, the Medical Research Council, The Wellcome Trust, UCL Business (Proof of Concept Grant) and the Rosetrees Trust. J.W.B.B. is supported by a NIHR Research Professorship. H.M.A. is supported by a British Heart Foundation Senior Fellowship. We would also like to thank M. Gillies for his role in initiating the original project, P. Luthert and C. Thaung for human tissue samples and advice on human pathology specimens, S. Perkins and R. Nan for assistance with the surface plasmon resonance analysis, and P. ten Dijke for discussions and advice.
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The project was conceived by J.G., S.E.M. and X.W. Experiments were designed by J.G., S.E.M., X.W. and S.A. Microarrays were performed by J.A.G.M. and qPCR reactions by X.W. X.W. and S.A. characterized the Lrg1 knockout mice and LRG1 antibody. X.W. performed all the metatarsal assays (except in Fig. 5j, k), aortic ring assays and Matrigel assays, carried out all the biochemical and molecular biology work and analysed the data. S.A. and X.W. undertook the immunohistochemistry and generated the OIR mouse model. U.F.O.L., C.A.K.L., S.A., X.W. and J.W.B.B. performed the CNV experiments, and S.A. and X.W. analysed the data. J.W.B.B. provided human vitreal samples. Z.Z. and H.M.A. generated MLEC;Engfl/fl cells and X.W. performed proliferation assay and biochemical analysis. Z.Z., S.A. and H.M.A. carried out the metatarsal assays on Eng knockout mice. V.B.T. performed the Biacore experiments. N.J. and M.S. provided assistance and technique support. X.W., S.A., J.G. and S.E.M. produced the figures, and J.G. and S.E.M. wrote the text, with all authors contributing to the final manuscript. J.G. and S.E.M. provided leadership throughout the project.
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This file contains Supplementary Figures 1-32 and Supplementary Tables 1-2. (PDF 3431 kb)
Three dimensional reconstruction of normal mouse retinal vasculature.
A scanning laser confocal microscopy Z-stack of control 16 week old adult C57/BL6 mouse retina stained for collagen IV (green), PECAM-1 (red) and cell nuclei (blue) was volume rendered to create a three-dimensional reconstruction of the retinal vasculature using Imaris software (Bitplane AG). The inner, intermediate and deep vasculature plexuses can be observed. (MOV 5474 kb)
Three dimensional reconstruction of VLDLR-/- mouse retinal vasculature.
A scanning laser confocal microscopy Z-stack of 18 week old VLDLR-/- mouse retina stained for collagen IV (green), PECAM-1 (red) and cell nuclei (blue) was volume rendered to create a three-dimensional reconstruction of the retinal vasculature using Imaris software (Bitplane AG). Abnormal vascular tufts can be seen penetrating the outer nuclear layer and extending into the sub-retinal space. (MOV 5646 kb)
Three dimensional reconstruction of Grhl3ct/J curly tail mouse retinal vasculature.
A scanning laser confocal microscopy Z-stack of 16 week old Grhl3ct/J curly tail mouse retina stained for collagen IV (green), PECAM-1 (red) and cell nuclei (blue) was volume rendered to create a three-dimensional reconstruction of the retinal vasculature using Imaris software (Bitplane AG). Abnormal vascular projections can be seen penetrating the outer nuclear layer and extending into the sub-retinal space. (MOV 23705 kb)
Three dimensional reconstruction of RD1 mouse retinal vasculature
A scanning laser confocal microscopy Z-stack of 18 week old RD1 mouse retina stained for collagen IV (green), PECAM-1 (red) and cell nuclei (blue) was volume rendered to create a three-dimensional reconstruction of the retinal vasculature using Imaris software (Bitplane AG). Retinal thinning can be seen due to degeneration of photoreceptors (loss of outer nuclear layer compared with WT mice) with a concomitant reduction in retinal vasculature. Abnormal tortuous vessels can be observed. (MOV 4898 kb)
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Wang, X., Abraham, S., McKenzie, J. et al. LRG1 promotes angiogenesis by modulating endothelial TGF-β signalling. Nature 499, 306–311 (2013). https://doi.org/10.1038/nature12345
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DOI: https://doi.org/10.1038/nature12345
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