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Ruhrberg C, Bautch VL. Neurovascular development and links to disease. Cell Mol Life Sci 2013; 70:1675-84. [PMID: 23475065 PMCID: PMC3632722 DOI: 10.1007/s00018-013-1277-5] [Citation(s) in RCA: 67] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2013] [Revised: 01/28/2013] [Accepted: 01/28/2013] [Indexed: 12/22/2022]
Abstract
The developing central nervous system (CNS) is vascularized via ingression of blood vessels from the outside as the neural tissue expands. This angiogenic process occurs without perturbing CNS architecture due to exquisite cross-talk between the neural compartment and invading blood vessels. Subsequently, this intimate relationship also promotes the formation of the neurovascular unit that underlies the blood-brain barrier and regulates blood flow to match brain activity. This review provides a historical perspective on research into CNS blood vessel growth and patterning, discusses current models used to study CNS angiogenesis, and provides an overview of the cellular and molecular mechanisms that promote blood vessel growth and maturation. Finally, we highlight the significance of these mechanisms for two different types of neurovascular CNS disease.
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Affiliation(s)
- Christiana Ruhrberg
- UCL Institute of Ophthalmology, University College London, 11-43 Bath Street, London, EC1V 9EL, UK.
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202
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Xu H, Heilshorn SC. Microfluidic investigation of BDNF-enhanced neural stem cell chemotaxis in CXCL12 gradients. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2013; 9:585-95. [PMID: 23109183 PMCID: PMC3984949 DOI: 10.1002/smll.201202208] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Indexed: 05/24/2023]
Abstract
In vivo studies have suggested that gradients of CXCL12 (aka stromal cell-derived factor 1α) may be critical for neural stem cell (NSC) migration during brain development and neural tissue regeneration. However, traditional in vitro chemotaxis tools are limited by unstable concentration gradients and the inability to decouple cell migration directionality and speed. These limitations have restricted the reproducible and quantitative analysis of neuronal migration, which is required for mechanism-based studies. Using a microfluidic gradient generator, nestin and Sox-2 positive human embryonic NSC chemotaxis is quantified within a linear and stable CXCL12 gradient. While untreated NSCs are not able to chemotax within CXCL12 gradients, pre-treatment of the cells with brain-derived neurotrophic factor (BDNF) results in significant chemotactic, directional migration. BDNF pre-treatment has no effect on cell migration speed, which averages about 1 μm min(-1). Quantitative analysis determines that CXCL12 concentrations above 9.0 nM are above the minimum activation threshold, while concentrations below 14.7 nM are below the saturation threshold. Interestingly, although inhibitor studies with AMD 3100 revealed that CXCL12 chemotaxis requires receptor CXCR4 activation, BDNF pre-treatment is found to have no profound effects on the mRNA levels or surface presentation of CXCR4 or the putative CXCR7 scavenger receptor. The microfluidic study of NSC migration within stable chemokine concentration profiles provides quantitative analysis as well as new insight into the migratory mechanism underlying BDNF-induced chemotaxis towards CXCL12.
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203
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Lippmann ES, Azarin SM, Kay JE, Nessler RA, Wilson HK, Al-Ahmad A, Palecek SP, Shusta EV. Derivation of blood-brain barrier endothelial cells from human pluripotent stem cells. Nat Biotechnol 2013; 30:783-91. [PMID: 22729031 PMCID: PMC3467331 DOI: 10.1038/nbt.2247] [Citation(s) in RCA: 520] [Impact Index Per Article: 47.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/04/2012] [Accepted: 04/30/2012] [Indexed: 11/09/2022]
Abstract
The blood-brain barrier (BBB) is crucial to the health of the brain and is often compromised in neurological disease. Moreover, because of its barrier properties, this endothelial interface restricts uptake of neurotherapeutics. Thus, a renewable source of human BBB endothelium could spur brain research and pharmaceutical development. Here we show that endothelial cells derived from human pluripotent stem cells (hPSCs) acquire BBB properties when co-differentiated with neural cells that provide relevant cues, including those involved in Wnt/β-catenin signaling. The resulting endothelial cells have many BBB attributes, including well-organized tight junctions, appropriate expression of nutrient transporters and polarized efflux transporter activity. Notably, they respond to astrocytes, acquiring substantial barrier properties as measured by transendothelial electrical resistance (1,450 ± 140 Ω cm2), and they possess molecular permeability that correlates well with in vivo rodent blood-brain transfer coefficients.
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Affiliation(s)
- Ethan S Lippmann
- Department of Chemical and Biological Engineering, University of Wisconsin–Madison, Madison, Wisconsin, USA
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204
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Shamloo A, Heibatollahi M, Ghafar-Zadeh E. Parallel in-vitro and in-vivo techniques for optimizing cellular microenvironments by implementing biochemical, biomechanical and electromagnetic stimulations. ANNUAL INTERNATIONAL CONFERENCE OF THE IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. IEEE ENGINEERING IN MEDICINE AND BIOLOGY SOCIETY. ANNUAL INTERNATIONAL CONFERENCE 2013; 2012:1397-400. [PMID: 23366161 DOI: 10.1109/embc.2012.6346200] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Development of novel engineering techniques that can promote new clinical treatments requires implementing multidisciplinary in-vitro and in-vivo approaches. In this study, we have implemented microfluidic devices and in-vivo rat model to study the mechanism of neural stem cell migration and differentiation. These studies can result in the treatment of damages to the neuronal system. In this research, we have shown that by applying appropriate ranges of biochemical and biomechanical factors as well as by exposing the cells to electromagnetic fields, it is possible to improve viability, proliferation, directional migration and differentiation of neural stem cells. The results of this study can be implemented in the design of optimized platforms that can be transplanted into the damaged areas of the neuronal system.
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205
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Modeling the blood-brain barrier using stem cell sources. Fluids Barriers CNS 2013; 10:2. [PMID: 23305164 PMCID: PMC3564868 DOI: 10.1186/2045-8118-10-2] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2012] [Accepted: 11/13/2012] [Indexed: 12/18/2022] Open
Abstract
The blood–brain barrier (BBB) is a selective endothelial interface that controls trafficking between the bloodstream and brain interstitial space. During development, the BBB arises as a result of complex multicellular interactions between immature endothelial cells and neural progenitors, neurons, radial glia, and pericytes. As the brain develops, astrocytes and pericytes further contribute to BBB induction and maintenance of the BBB phenotype. Because BBB development, maintenance, and disease states are difficult and time-consuming to study in vivo, researchers often utilize in vitro models for simplified analyses and higher throughput. The in vitro format also provides a platform for screening brain-penetrating therapeutics. However, BBB models derived from adult tissue, especially human sources, have been hampered by limited cell availability and model fidelity. Furthermore, BBB endothelium is very difficult if not impossible to isolate from embryonic animal or human brain, restricting capabilities to model BBB development in vitro. In an effort to address some of these shortcomings, advances in stem cell research have recently been leveraged for improving our understanding of BBB development and function. Stem cells, which are defined by their capacity to expand by self-renewal, can be coaxed to form various somatic cell types and could in principle be very attractive for BBB modeling applications. In this review, we will describe how neural progenitor cells (NPCs), the in vitro precursors to neurons, astrocytes, and oligodendrocytes, can be used to study BBB induction. Next, we will detail how these same NPCs can be differentiated to more mature populations of neurons and astrocytes and profile their use in co-culture modeling of the adult BBB. Finally, we will describe our recent efforts in differentiating human pluripotent stem cells (hPSCs) to endothelial cells with robust BBB characteristics and detail how these cells could ultimately be used to study BBB development and maintenance, to model neurological disease, and to screen neuropharmaceuticals.
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206
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Sohet F, Daneman R. Genetic mouse models to study blood-brain barrier development and function. Fluids Barriers CNS 2013; 10:3. [PMID: 23305182 PMCID: PMC3675378 DOI: 10.1186/2045-8118-10-3] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 11/20/2012] [Indexed: 12/21/2022] Open
Abstract
The blood–brain barrier (BBB) is a complex physiological structure formed by the blood vessels of the central nervous system (CNS) that tightly regulates the movement of substances between the blood and the neural tissue. Recently, the generation and analysis of different genetic mouse models has allowed for greater understanding of BBB development, how the barrier is regulated during health, and its response to disease. Here we discuss: 1) Genetic mouse models that have been used to study the BBB, 2) Available mouse genetic tools that can aid in the study of the BBB, and 3) Potential tools that if generated could greatly aid in our understanding of the BBB.
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Affiliation(s)
- Fabien Sohet
- UCSF Department of Anatomy, 513 Parnassus Ave HSW1301, San Francisco, 94117, California, USA.
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207
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Eichmann A, Thomas JL. Molecular parallels between neural and vascular development. Cold Spring Harb Perspect Med 2013; 3:a006551. [PMID: 23024177 DOI: 10.1101/cshperspect.a006551] [Citation(s) in RCA: 95] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
The human central nervous system (CNS) features a network of ~400 miles of blood vessels that receives >20% of the body's cardiac output and uses most of its blood glucose. Many human diseases, including stroke, retinopathy, and cancer, are associated with the biology of CNS blood vessels. These vessels originate from extrinsic cell populations, including endothelial cells and pericytes that colonize the CNS and interact with glia and neurons to establish the blood-brain barrier and control cerebrovascular exchanges. Neurovascular interactions also play important roles in adult neurogenic niches, which harbor a unique population of neural stem cells that are intimately associated with blood vessels. We here review the cellular and molecular mechanisms required to establish the CNS vascular network, with a special focus on neurovascular interactions and the functions of vascular endothelial growth factors.
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Affiliation(s)
- Anne Eichmann
- Center for Interdisciplinary Research in Biology, CNRS/UMR 7241-INSERM U1050, Collège de France, 75005 Paris, France.
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208
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Daneman R. The blood-brain barrier in health and disease. Ann Neurol 2012; 72:648-72. [DOI: 10.1002/ana.23648] [Citation(s) in RCA: 482] [Impact Index Per Article: 40.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2011] [Revised: 05/02/2012] [Accepted: 05/04/2012] [Indexed: 12/12/2022]
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209
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Burgos-Paz W, Souza CA, Megens HJ, Ramayo-Caldas Y, Melo M, Lemús-Flores C, Caal E, Soto HW, Martínez R, Alvarez LA, Aguirre L, Iñiguez V, Revidatti MA, Martínez-López OR, Llambi S, Esteve-Codina A, Rodríguez MC, Crooijmans RPMA, Paiva SR, Schook LB, Groenen MAM, Pérez-Enciso M. Porcine colonization of the Americas: a 60k SNP story. Heredity (Edinb) 2012; 110:321-30. [PMID: 23250008 DOI: 10.1038/hdy.2012.109] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
The pig, Sus scrofa, is a foreign species to the American continent. Although pigs originally introduced in the Americas should be related to those from the Iberian Peninsula and Canary islands, the phylogeny of current creole pigs that now populate the continent is likely to be very complex. Because of the extreme climates that America harbors, these populations also provide a unique example of a fast evolutionary phenomenon of adaptation. Here, we provide a genome wide study of these issues by genotyping, with a 60k SNP chip, 206 village pigs sampled across 14 countries and 183 pigs from outgroup breeds that are potential founders of the American populations, including wild boar, Iberian, international and Chinese breeds. Results show that American village pigs are primarily of European ancestry, although the observed genetic landscape is that of a complex conglomerate. There was no correlation between genetic and geographical distances, neither continent wide nor when analyzing specific areas. Most populations showed a clear admixed structure where the Iberian pig was not necessarily the main component, illustrating how international breeds, but also Chinese pigs, have contributed to extant genetic composition of American village pigs. We also observe that many genes related to the cardiovascular system show an increased differentiation between altiplano and genetically related pigs living near sea level.
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Affiliation(s)
- W Burgos-Paz
- Centre for Research in Agricultural Genomics (CRAG)-Universitat Autònoma de Barcelona (UAB), Bellaterra, Spain
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210
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McAdams RM, Vanderhoeven J, Beyer RP, Bammler TK, Farin FM, Liggitt HD, Kapur RP, Gravett MG, Rubens CE, Adams Waldorf KM. Choriodecidual infection downregulates angiogenesis and morphogenesis pathways in fetal lungs from Macaca nemestrina. PLoS One 2012; 7:e46863. [PMID: 23056493 PMCID: PMC3467273 DOI: 10.1371/journal.pone.0046863] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2012] [Accepted: 09/06/2012] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Intrauterine exposure to amniotic fluid (AF) cytokines is thought to predispose to bronchopulmonary dysplasia (BPD). We evaluated the effects of GBS exposure on RNA expression in fetal lung tissue to determine early molecular pathways associated with fetal lung injury that may progress to BPD. METHODS Ten chronically catheterized pregnant monkeys (Macaca nemestrina) at 118-125 days gestation (term = 172 days) received choriodecidual inoculation of either: 1) Group B Streptococcus (n = 5) or 2) saline (n = 5). Cesarean section and fetal necropsy was performed in the first week after GBS or saline inoculation regardless of labor. RNA was extracted from fetal lungs and profiled by microarray. Results were analyzed using single gene, Gene Set, and Ingenuity Pathway Analysis. Validation was by RT-PCR and immunohistochemistry. RESULTS Despite uterine quiescence in most cases, fetal lung injury occurred in four GBS cases (intra-alveolar neutrophils, interstitial thickening) and one control (peri-mortem hemorrhage). Significant elevations of AF cytokines (TNF-α, IL-8, IL-1β, IL-6) were detected in GBS versus controls (p<0.05). Lung injury was not directly caused by GBS, because GBS was undetectable by culture and PCR in the AF and fetal lungs. A total of 335 genes were differentially expressed greater than 1.5 fold (p<0.05) with GBS exposure associated with a striking upregulation of genes in innate and adaptive immunity and downregulation of pathways for angiogenesis, morphogenesis, and cellular growth and development. CONCLUSIONS A transient choriodecidual infection may induce fetal lung injury with profound alterations in the genetic program of the fetal lung before signs of preterm labor. Our results provide a window for the first time into early molecular pathways disrupting fetal lung angiogenesis and morphogenesis before preterm labor occurs, which may set the stage for BPD. A strategy to prevent BPD should target the fetus in utero to attenuate alterations in the fetal lung genetic program.
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Affiliation(s)
- Ryan M. McAdams
- Department of Pediatrics, University of Washington, Seattle, Washington, United States of America
| | - Jeroen Vanderhoeven
- Department of Obstetrics & Gynecology, University of Washington, Seattle, Washington, United States of America
| | - Richard P. Beyer
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, United States of America
| | - Theo K. Bammler
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, United States of America
| | - Federico M. Farin
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington, United States of America
| | - H. Denny Liggitt
- Department of Comparative Medicine, University of Washington, Seattle, Washington, United States of America
| | - Raj P. Kapur
- Department of Laboratories, Seattle Children’s, Seattle, Washington, United States of America
| | - Michael G. Gravett
- Department of Obstetrics & Gynecology, University of Washington, Seattle, Washington, United States of America
- Global Alliance to Prevent Prematurity & Stillbirth, Seattle, Washington, United States of America
| | - Craig E. Rubens
- Department of Pediatrics, University of Washington, Seattle, Washington, United States of America
- Global Alliance to Prevent Prematurity & Stillbirth, Seattle, Washington, United States of America
- Division of Infectious Disease, Seattle Children’s, Seattle, Washington, United States of America
| | - Kristina M. Adams Waldorf
- Department of Obstetrics & Gynecology, University of Washington, Seattle, Washington, United States of America
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211
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Abstract
VEGF-A signaling is required for almost every aspect of vascular development, and it is a major regulator of vessel morphogenesis and patterning. VEGF-A perturbations are associated with severe vascular defects and lethality, and the pathway is coopted in pathological scenarios, including tumor angiogenesis. This review focuses on the roles of VEGF-A signaling during vessel development and patterning. I review the impact of VEGF-A signaling on endothelial cells in developing vessels, with emphasis on the importance of spatial regulation of several pathway components. I also discuss VEGF-A signaling patterns at the level of the vessel, with a focus on how polarity is set up and maintained in several vessel axes. The role of VEGF-A in patterning vessels relative to tissues and organs is also reviewed, with emphasis on neurovascular patterning and patterning at the embryonic midline.
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212
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Yang L, Xu L. GPR56 in cancer progression: current status and future perspective. Future Oncol 2012; 8:431-40. [PMID: 22515446 DOI: 10.2217/fon.12.27] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022] Open
Abstract
Cell adhesion is a critical process during cancer progression and is mediated by transmembrane receptors. Recently, GPR56, a member of the adhesion family of G protein-coupled receptors, was established as a new type of adhesion receptor that binds to extracellular matrix proteins and shown to play inhibitory roles in melanoma progression. Further studies revealed that the extracellular portion and the seven transmembrane domains of GPR56 function antagonistically to regulate VEGF production and angiogenesis via a signaling pathway mediated by PKCα. Tissue transglutaminase was identified as the first extracellular matrix protein that binds to GPR56. It is a crosslinking enzyme in the extracellular matrix but is also expressed in the cytosol. Tissue transglutaminase plays pleiotropic roles in cancer progression. Whether and how it might mediate GPR56-regulated cancer progression awaits further investigation.
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Affiliation(s)
- Liquan Yang
- Department of Biomedical Genetics, Department of Dermatology, James P Wilmot Cancer Center, University of Rochester Medical Center, Rochester, NY 14642, USA
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213
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Chen Q, Jiang L, Li C, Hu D, Bu JW, Cai D, Du JL. Haemodynamics-driven developmental pruning of brain vasculature in zebrafish. PLoS Biol 2012; 10:e1001374. [PMID: 22904685 PMCID: PMC3419171 DOI: 10.1371/journal.pbio.1001374] [Citation(s) in RCA: 155] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2012] [Accepted: 07/05/2012] [Indexed: 11/21/2022] Open
Abstract
This in vivo time-lapse imaging study in zebrafish reveals how changes to brain blood flow drive vessel pruning via endothelial cell migration, and how pruning leads to the simplification of the brain vasculature during development. Although the brain comprises only 2% of body weight, it receives 15% of cardiac output and consumes 20% of total body oxygen delivered through its blood vasculature. The brain blood vasculature consists of a highly branched vessel network that is tailored to efficiently deliver oxygen and nutrients to each brain region. However, little is known about how the brain vasculature develops. Using in vivo long-term serial confocal imaging of zebrafish larvae, we analyze this process and find that the developing midbrain vasculature undergoes not only vessel growth but also blood flow-driven vessel pruning. We show that vessel pruning occurs preferentially at loop-shaped vessel segments via the migration of endothelial cells to adjacent unpruned segments; over time, such vessel pruning reduces the complexity of the early primitive midbrain vasculature. We also observe that pruned vessel segments exhibit a lower and more variable blood flow than do unpruned segments and that the local blocking of blood flow triggers vessel pruning. By contrast, increases in blood flow impair vessel pruning. Finally, we show that pruning events can be predicted using a haemodynamics based mathematical model of the midbrain vasculature. These findings demonstrate the existence of brain vessel pruning during development and provide novel insights into the role of haemodynamics in brain vascular refinement. The brain blood vasculature consists of a highly ramified vessel network that is tailored to meet its physiological functions. How the brain vasculature is formed has long been fascinating biologists. Here we report that the developing vasculature in the zebrafish midbrain undergoes not only angiogenesis but also extensive vessel pruning, which is driven by changes in blood flow. This pruning process shapes the initial exuberant interconnected meshwork into a simplified architecture. Using in vivo long-term serial confocal imaging of the same zebrafish larvae during 1.5–7.5 d post-fertilization, we found that the early formed midbrain vasculature consisted of many vessel loops and higher order segments. Vessel pruning occurred preferentially at loop-forming segments via a process mainly involving lateral migration of endothelial cells (ECs) from pruned to unpruned segments rather than EC apoptosis, leading to gradual reduction in the vasculature complexity with development. Compared to unpruned ones, pruned segments exhibited a low and variable blood flow, which further decreased irreversibly prior to the onset of pruning. Local blockade of blood flow with micro-bead obstruction led to vessel pruning, whereas increasing blood flow by noradrenergic elevation of heartbeat impeded the pruning process. Furthermore, the occurrence of vessel pruning could be largely predicted by haemodynamics-based numerical simulation of vasculature refinement. Thus, changes of blood flow drive vessel pruning via lateral migration of ECs, leading to the simplification of the vasculature and possibly efficient routing of blood flow in the developing brain.
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Affiliation(s)
- Qi Chen
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Luan Jiang
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Chun Li
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - Dan Hu
- Department of Mathematics and Institute of Natural Sciences, Shanghai Jiaotong University, Shanghai, China
| | - Ji-wen Bu
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
| | - David Cai
- Department of Mathematics and Institute of Natural Sciences, Shanghai Jiaotong University, Shanghai, China
- Courant Institute of Mathematical Sciences and Center for Neural Science, New York University, New York, United States of America
| | - Jiu-lin Du
- Institute of Neuroscience and State Key Laboratory of Neuroscience, Shanghai Institutes for Biological Sciences, Chinese Academy of Sciences, Shanghai, China
- * E-mail:
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214
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G Protein-Coupled Receptor 124 (GPR124) Gene Polymorphisms and Risk of Brain Arteriovenous Malformation. Transl Stroke Res 2012; 3:418-27. [PMID: 23329986 DOI: 10.1007/s12975-012-0202-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022]
Abstract
Abnormal endothelial proliferation and angiogenesis may contribute to brain arteriovenous malformation (BAVM) formation. G protein-coupled receptor 124 (GPR124) mediates embryonic CNS angiogenesis; thus we investigated the association of single nucleotide polymorphisms (SNPs) and haplotypes in GPR124 with risk of BAVM. Ten tagging SNPs spanning 39 kb of GPR124 were genotyped in 195 Caucasian BAVM patients and 243 Caucasian controls. SNP and haplotype association with risk of BAVM was screened using χ(2) analysis. Associated variants were further evaluated using multivariable logistic regression, adjusting for age and sex. The minor alleles of 3 GPR124 SNPs adjacent to exon 2 and localized to a 16 kb region of high linkage disequilibrium were associated with reduced risk of BAVM (rs7015566 A, P=0.001; rs7823249 T, P=0.014; rs12676965 C, P=0.007). SNP rs7015566 (intron 1) remained associated after permutation testing (additive model P=0.033). Haplotype analysis revealed a significant overall association (χ(2)=12.55, 4 df, P=0.014); 2 haplotypes (ATCC, P=0.006 and GGCT, P=0.008) were associated with risk of BAVM. We genotyped a known synonymous SNP (rs16887051) in exon 2, however genotype frequency did not differ between cases and controls. Sequencing of conserved GPR124 regions revealed a novel indel polymorphism in intron 2. Immunohistochemistry confirmed GPR124 expression in the endothelium with no qualitative difference in expression between BAVM cases and controls. SNP rs7015566 mapping to intron 1 of GPR124 was associated with BAVM susceptibility among Caucasians. Future work is focused on investigating this gene region.
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215
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Tang XL, Wang Y, Li DL, Luo J, Liu MY. Orphan G protein-coupled receptors (GPCRs): biological functions and potential drug targets. Acta Pharmacol Sin 2012; 33:363-71. [PMID: 22367282 DOI: 10.1038/aps.2011.210] [Citation(s) in RCA: 123] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
The superfamily of G protein-coupled receptors (GPCRs) includes at least 800 seven-transmembrane receptors that participate in diverse physiological and pathological functions. GPCRs are the most successful targets of modern medicine, and approximately 36% of marketed pharmaceuticals target human GPCRs. However, the endogenous ligands of more than 140 GPCRs remain unidentified, leaving the natural functions of those GPCRs in doubt. These are the so-called orphan GPCRs, a great source of drug targets. This review focuses on the signaling transduction pathways of the adhesion GPCR family, the LGR subfamily, and the PSGR subfamily, and their potential functions in immunology, development, and cancers. In this review, we present the current approaches and difficulties of orphan GPCR deorphanization and characterization.
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216
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Wallgard E, Nitzsche A, Larsson J, Guo X, Dieterich LC, Dimberg A, Olofsson T, Pontén FC, Mäkinen T, Kalén M, Hellström M. Paladin (X99384) is expressed in the vasculature and shifts from endothelial to vascular smooth muscle cells during mouse development. Dev Dyn 2012; 241:770-86. [PMID: 22354871 DOI: 10.1002/dvdy.23753] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/25/2012] [Indexed: 11/11/2022] Open
Abstract
BACKGROUND Angiogenesis is implicated in many pathological conditions. The role of the proteins involved remains largely unknown, and few vascular-specific drug targets have been discovered. Previously, in a screen for angiogenesis regulators, we identified Paladin (mouse: X99384, human: KIAA1274), a protein containing predicted S/T/Y phosphatase domains. RESULTS We present a mouse knockout allele for Paladin with a β-galactosidase reporter, which in combination with Paladin antibodies demonstrate that Paladin is expressed in the vasculature. During mouse embryogenesis, Paladin is primarily expressed in capillary and venous endothelial cells. In adult mice Paladin is predominantly expressed in arterial pericytes and vascular smooth muscle cells. Paladin also displays vascular-restricted expression in human brain, astrocytomas, and glioblastomas. CONCLUSIONS Paladin, a novel putative phosphatase, displays a dynamic expression pattern in the vasculature. During embryonic stages it is broadly expressed in endothelial cells, while in the adult it is selectively expressed in arterial smooth muscle cells.
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Affiliation(s)
- Elisabet Wallgard
- Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University, Uppsala, Sweden
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217
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Cortical neurogenesis and morphogens: diversity of cues, sources and functions. Curr Opin Cell Biol 2012; 24:269-76. [PMID: 22342580 DOI: 10.1016/j.ceb.2012.01.010] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2011] [Revised: 01/16/2012] [Accepted: 01/18/2012] [Indexed: 01/29/2023]
Abstract
The cerebral cortex is composed of hundreds of different types of neurons, which underlie its ability to perform highly complex neural processes. How cortical neurons are generated during development constitutes a major challenge in developmental neurosciences with important implications for brain repair and diseases. Cortical neurogenesis is dependent on intrinsic and extrinsic cues, which interplay to generate cortical neurons at the right number, time and place. While the role of intrinsic factors such as proneural and Notch genes has been well established, recent evidence indicate that most classical morphogens, produced by various neural and non-neural sources throughout embryonic development, contribute to the master control and fine tuning of cortical neurogenesis. Here we review some recent advances in the dissection of the molecular logic underlying neurogenesis in the cortex, with special emphasis on the roles of morphogenic cues in this process.
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218
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Araç D, Boucard AA, Bolliger MF, Nguyen J, Soltis SM, Südhof TC, Brunger AT. A novel evolutionarily conserved domain of cell-adhesion GPCRs mediates autoproteolysis. EMBO J 2012; 31:1364-78. [PMID: 22333914 PMCID: PMC3321182 DOI: 10.1038/emboj.2012.26] [Citation(s) in RCA: 321] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/26/2011] [Accepted: 01/16/2012] [Indexed: 12/02/2022] Open
Abstract
Crystallographic structures encompassing GPCR autoproteolytic sequences (GPS) delineate a novel conserved structural domain called GAIN, which is found in cell-adhesion GPCRs, polycystic kidney disease proteins conserved throughout evolution. The G protein-coupled receptor (GPCR) Proteolysis Site (GPS) of cell-adhesion GPCRs and polycystic kidney disease (PKD) proteins constitutes a highly conserved autoproteolysis sequence, but its catalytic mechanism remains unknown. Here, we show that unexpectedly the ∼40-residue GPS motif represents an integral part of a much larger ∼320-residue domain that we termed GPCR-Autoproteolysis INducing (GAIN) domain. Crystal structures of GAIN domains from two distantly related cell-adhesion GPCRs revealed a conserved novel fold in which the GPS motif forms five β-strands that are tightly integrated into the overall GAIN domain. The GAIN domain is evolutionarily conserved from tetrahymena to mammals, is the only extracellular domain shared by all human cell-adhesion GPCRs and PKD proteins, and is the locus of multiple human disease mutations. Functionally, the GAIN domain is both necessary and sufficient for autoproteolysis, suggesting an autoproteolytic mechanism whereby the overall GAIN domain fine-tunes the chemical environment in the GPS to catalyse peptide bond hydrolysis. Thus, the GAIN domain embodies a unique, evolutionarily ancient and widespread autoproteolytic fold whose function is likely relevant for GPCR signalling and for multiple human diseases.
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Affiliation(s)
- Demet Araç
- Howard Hughes Medical Institute, Stanford, CA, USA.
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219
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Activation of myeloid cell-specific adhesion class G protein-coupled receptor EMR2 via ligation-induced translocation and interaction of receptor subunits in lipid raft microdomains. Mol Cell Biol 2012; 32:1408-20. [PMID: 22310662 DOI: 10.1128/mcb.06557-11] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
The adhesion class G protein-coupled receptors (adhesion-GPCRs) play important roles in diverse biological processes ranging from immunoregulation to tissue polarity, angiogenesis, and brain development. These receptors are uniquely modified by self-catalytic cleavage at a highly conserved GPCR proteolysis site (GPS) dissecting the receptor into an extracellular subunit (α) and a seven-pass transmembrane subunit (β) with cellular adhesion and signaling functions, respectively. Using the myeloid cell-restricted EMR2 receptor as a paradigm, we exam the mechanistic relevance of the subunit interaction and demonstrate a critical role for GPS autoproteolysis in mediating receptor signaling and cell activation. Interestingly, two distinct receptor complexes are identified as a result of GPS proteolysis: one consisting of a noncovalent α-β heterodimer and the other comprising two completely independent receptor subunits which distribute differentially in membrane raft microdomains. Finally, we show that receptor ligation induces subunit translocation and colocalization within lipid rafts, leading to receptor signaling and inflammatory cytokine production by macrophages. Our present data resolve earlier conflicting results and provide a new mechanism of receptor signaling, as well as providing a paradigm for signal transduction within the adhesion-GPCR family.
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220
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Knudsen TB, Kleinstreuer NC. Disruption of embryonic vascular development in predictive toxicology. ACTA ACUST UNITED AC 2012; 93:312-23. [DOI: 10.1002/bdrc.20223] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
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221
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Thrombin-induced shedding of tumour endothelial marker 5 and exposure of its RGD motif are regulated by cell-surface protein disulfide-isomerase. Biochem J 2012; 441:937-44. [DOI: 10.1042/bj20111682] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
TEM5 (tumour endothelial marker 5; also known as GPR124) is an adhesion G-protein-coupled receptor containing a cryptic RGD motif in its extracellular domain. TEM5 is expressed in endothelial cells and pericytes during angiogenesis. In the present paper, we report that thrombin mediates shedding of an N-terminal TEM5 fragment of 60 kDa (termed N60) containing the RGD motif in an open conformation. Thrombin directly cleaved rsTEM5 (recombinant soluble TEM5) 5 and 34 residues downstream of the RGD motif, resulting in formation of N60 and its C-terminal counterpart (termed C50). Interestingly, N60 derived from thrombin cleavage of rsTEM5 was covalently linked to C50 by disulfide bonds, whereas N60 shed from thrombin-treated cells was not associated with its membrane-bound C-terminal counterpart. Inhibition of the reducing function of cell-surface PDI (protein disulfide-isomerase) abrogated thrombin-induced N60 shedding. Conversely, addition of reduced PDI enhanced N60 shedding. Furthermore, thrombin cleavage of rsTEM5 was increased by reduced PDI and resulted in dissociation of the N60–C50 heterodimer. We conclude that PDI regulates thrombin-induced shedding of N60 and exposure of the TEM5 RGD motif by catalysing the reduction of crucial disulfide bonds of TEM5 on the cell surface. Binding of N60 to RGD-dependent integrins may modulate cellular functions such as adhesion and migration during angiogenesis.
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222
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Nguyen HL, Lee YJ, Shin J, Lee E, Park SO, McCarty JH, Oh SP. TGF-β signaling in endothelial cells, but not neuroepithelial cells, is essential for cerebral vascular development. J Transl Med 2011; 91:1554-63. [PMID: 21876535 PMCID: PMC3802535 DOI: 10.1038/labinvest.2011.124] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/14/2023] Open
Abstract
The various organs of the body harbor blood vessel networks that display unique structural and functional features; however, the mechanisms that control organ-specific vascular development and physiology remain mostly unknown. In the developing mouse brain, αvβ8 integrin-mediated TGF-β activation and signaling is essential for normal blood vessel growth and sprouting. Whether integrins activate TGF-β signaling pathways in vascular endothelial cells (ECs), neural cells, or both, has yet to be determined. Here, we have generated and characterized mice in which TGF-β receptors are specifically deleted in neuroepithelial cells via Nestin-Cre, or in ECs via a novel Cre transgenic strain (Alk1(GFPCre)) in which Cre is expressed under control of the endogenous activin receptor-like kinase 1 (Alk1) promoter. We report that deletion of Tgfbr2 in the neuroepithelium does not impact brain vascular development. In contrast, selective deletion of the Tgfbr2 or Alk5 genes in ECs result in embryonic lethality because of brain-specific vascular pathologies, including blood vessel morphogenesis and intracerebral hemorrhage. These data reveal for the first time that αvβ8 integrin-activated TGF-βs regulate angiogenesis in the developing brain via paracrine signaling to ECs.
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Affiliation(s)
- Ha-Long Nguyen
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Young Jae Lee
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA,Laboratory of Developmental Genetics, Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon, Republic of Korea
| | - Jaekyung Shin
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Eunji Lee
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Sung Ok Park
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA
| | - Joseph H McCarty
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - S Paul Oh
- Department of Physiology and Functional Genomics, College of Medicine, University of Florida, Gainesville, FL, USA,Laboratory of Developmental Genetics, Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon, Republic of Korea,World Class University Program, Lee Gil Ya Cancer and Diabetes Institute, Gachon University of Medicine and Science, Incheon, Republic of Korea
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223
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Bohnekamp J, Schöneberg T. Cell adhesion receptor GPR133 couples to Gs protein. J Biol Chem 2011; 286:41912-41916. [PMID: 22025619 DOI: 10.1074/jbc.c111.265934] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Adhesion G protein-coupled receptors (GPCR), with their very large and complex N termini, are thought to participate in cell-cell and cell-matrix interactions and appear to be highly relevant in several developmental processes. Their intracellular signaling is still poorly understood. Here we demonstrate that GPR133, a member of the adhesion GPCR subfamily, activates the G(s) protein/adenylyl cyclase pathway. The presence of the N terminus and the cleavage at the GPCR proteolysis site are not required for G protein signaling. G(s) protein coupling was verified by Gα(s) knockdown with siRNA, overexpression of Gα(s), co-expression of the chimeric Gq(s4) protein that routes GPR133 activity to the phospholipase C/inositol phosphate pathway, and missense mutation within the transmembrane domain that abolished receptor activity without changing cell surface expression. It is likely that not only GPR133 but also other adhesion GPCR signal via classical receptor/G protein-interaction.
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Affiliation(s)
- Jens Bohnekamp
- Section of Molecular Biochemistry, Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany
| | - Torsten Schöneberg
- Section of Molecular Biochemistry, Institute of Biochemistry, Medical Faculty, University of Leipzig, 04103 Leipzig, Germany.
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224
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Armulik A, Genové G, Betsholtz C. Pericytes: developmental, physiological, and pathological perspectives, problems, and promises. Dev Cell 2011; 21:193-215. [PMID: 21839917 DOI: 10.1016/j.devcel.2011.07.001] [Citation(s) in RCA: 1810] [Impact Index Per Article: 139.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Pericytes, the mural cells of blood microvessels, have recently come into focus as regulators of vascular morphogenesis and function during development, cardiovascular homeostasis, and disease. Pericytes are implicated in the development of diabetic retinopathy and tissue fibrosis, and they are potential stromal targets for cancer therapy. Some pericytes are probably mesenchymal stem or progenitor cells, which give rise to adipocytes, cartilage, bone, and muscle. However, there is still confusion about the identity, ontogeny, and progeny of pericytes. Here, we review the history of these investigations, indicate emerging concepts, and point out problems and promise in the field of pericyte biology.
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Affiliation(s)
- Annika Armulik
- Division of Vascular Biology, Department of Medical Biochemistry and Biophysics, Karolinska Institute, SE-171 77 Stockholm, Sweden
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225
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226
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The Neurovascular Link in Health and Disease: Molecular Mechanisms and Therapeutic Implications. Neuron 2011; 71:406-24. [DOI: 10.1016/j.neuron.2011.07.013] [Citation(s) in RCA: 203] [Impact Index Per Article: 15.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/13/2011] [Indexed: 01/08/2023]
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227
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Abstract
Blood vessels deliver oxygen and nutrients to every part of the body, but also nourish diseases such as cancer. Over the past decade, our understanding of the molecular mechanisms of angiogenesis (blood vessel growth) has increased at an explosive rate and has led to the approval of anti-angiogenic drugs for cancer and eye diseases. So far, hundreds of thousands of patients have benefited from blockers of the angiogenic protein vascular endothelial growth factor, but limited efficacy and resistance remain outstanding problems. Recent preclinical and clinical studies have shown new molecular targets and principles, which may provide avenues for improving the therapeutic benefit from anti-angiogenic strategies.
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228
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Yang L, Chen G, Mohanty S, Scott G, Fazal F, Rahman A, Begum S, Hynes RO, Xu L. GPR56 Regulates VEGF production and angiogenesis during melanoma progression. Cancer Res 2011; 71:5558-68. [PMID: 21724588 DOI: 10.1158/0008-5472.can-10-4543] [Citation(s) in RCA: 84] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
Abstract
Angiogenesis is a critical step during cancer progression. The VEGF is a major stimulator for angiogenesis and is predominantly contributed by cancer cells in tumors. Inhibition of the VEGF signaling pathway has shown promising therapeutic benefits for cancer patients, but adaptive tumor responses are often observed, indicating the need for further understanding of VEGF regulation. We report that a novel G protein-coupled receptor, GPR56, inhibits VEGF production from the melanoma cell lines and impedes melanoma angiogenesis and growth, through the serine threonine proline-rich segment in its N-terminus and a signaling pathway involving protein kinase Cα. We also present evidence that the two fragments of GPR56, which are generated by autocatalyzed cleavage, played distinct roles in regulating VEGF production and melanoma progression. Finally, consistent with its suppressive roles in melanoma progression, the expression levels of GPR56 are inversely correlated with the malignancy of melanomas in human subjects. We propose that components of the GPR56-mediated signaling pathway may serve as new targets for antiangiogenic treatment of melanoma.
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Affiliation(s)
- Liquan Yang
- Departments of Biomedical Genetics, University of Rochester Medical Center, Rochester, New York 14612, USA
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229
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Ulrich F, Ma LH, Baker RG, Torres-Vázquez J. Neurovascular development in the embryonic zebrafish hindbrain. Dev Biol 2011; 357:134-51. [PMID: 21745463 DOI: 10.1016/j.ydbio.2011.06.037] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2010] [Revised: 06/10/2011] [Accepted: 06/13/2011] [Indexed: 01/05/2023]
Abstract
The brain is made of billions of highly metabolically active neurons whose activities provide the seat for cognitive, affective, sensory and motor functions. The cerebral vasculature meets the brain's unusually high demand for oxygen and glucose by providing it with the largest blood supply of any organ. Accordingly, disorders of the cerebral vasculature, such as congenital vascular malformations, stroke and tumors, compromise neuronal function and survival and often have crippling or fatal consequences. Yet, the assembly of the cerebral vasculature is a process that remains poorly understood. Here we exploit the physical and optical accessibility of the zebrafish embryo to characterize cerebral vascular development within the embryonic hindbrain. We find that this process is primarily driven by endothelial cell migration and follows a two-step sequence. First, perineural vessels with stereotypical anatomies are formed along the ventro-lateral surface of the neuroectoderm. Second, angiogenic sprouts derived from a subset of perineural vessels migrate into the hindbrain to form the intraneural vasculature. We find that these angiogenic sprouts reproducibly penetrate into the hindbrain via the rhombomere centers, where differentiated neurons reside, and that specific rhombomeres are invariably vascularized first. While the anatomy of intraneural vessels is variable from animal to animal, some aspects of the connectivity of perineural and intraneural vessels occur reproducibly within particular hindbrain locales. Using a chemical inhibitor of VEGF signaling we determine stage-specific requirements for this pathway in the formation of the hindbrain vasculature. Finally, we show that a subset of hindbrain vessels is aligned and/or in very close proximity to stereotypical neuron clusters and axon tracts. Using endothelium-deficient cloche mutants we show that the endothelium is dispensable for the organization and maintenance of these stereotypical neuron clusters and axon tracts in the early hindbrain. However, the cerebellum's upper rhombic lip and the optic tectum are abnormal in clo. Overall, this study provides a detailed, multi-stage characterization of early zebrafish hindbrain neurovascular development with cellular resolution up to the third day of age. This work thus serves as a useful reference for the neurovascular characterization of mutants, morphants and drug-treated embryos.
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Affiliation(s)
- Florian Ulrich
- Department of Developmental Genetics, Skirball Institute of Molecular Medicine, New York City, New York 10016, USA.
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230
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Dejana E, Nyqvist D. News from the brain: the GPR124 orphan receptor directs brain-specific angiogenesis. Sci Transl Med 2011; 2:58ps53. [PMID: 21084718 DOI: 10.1126/scitranslmed.3001793] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
During development, microvessels acquire specialized functions to meet the requirements of different tissues and organs. The vasculature of the brain constitutes one of the best examples of an organ-specific and highly specialized microvasculature, in which the endothelial cells that line blood vessels form an active permeability barrier and transport system called the blood-brain barrier (BBB); little is known, however, about the molecular mechanisms that instruct endothelial cells toward a BBB phenotype. Now Kuhnert et al. reveal that the orphan heterotrimeric GTP-binding protein-coupled receptor GPR124/TEM5 acts as an organ-specific regulator of brain angiogenesis, required for normal endothelial cell sprouting, migration, and expression of the BBB marker Glut-1 in the forebrain and neural tube. These findings add to our knowledge of brain vascularization and may open up possibilities for new therapeutic regimes to treat several diseases, including stroke, brain tumors, and vascular malformations.
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Affiliation(s)
- Elisabetta Dejana
- Milan University, Department of Biomolecular Sciences and Biotechnologies, Milan, Italy
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231
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Cullen M, Elzarrad MK, Seaman S, Zudaire E, Stevens J, Yang MY, Li X, Chaudhary A, Xu L, Hilton MB, Logsdon D, Hsiao E, Stein EV, Cuttitta F, Haines DC, Nagashima K, Tessarollo L, St. Croix B. GPR124, an orphan G protein-coupled receptor, is required for CNS-specific vascularization and establishment of the blood-brain barrier. Proc Natl Acad Sci U S A 2011; 108:5759-64. [PMID: 21421844 PMCID: PMC3078373 DOI: 10.1073/pnas.1017192108] [Citation(s) in RCA: 144] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023] Open
Abstract
Every organ in the body requires blood vessels for efficient delivery of oxygen and nutrients, but independent vascular beds are highly specialized to meet the individual needs of specific organs. The vasculature of the brain is tightly sealed, with blood-brain barrier (BBB) properties developing coincident with neural vascularization. G protein-coupled receptor 124 (GPR124) (tumor endothelial marker 5, TEM5), an orphan member of the adhesion family of G protein-coupled receptors, was previously identified on the basis of its overexpression in tumor vasculature. Here, we show that global deletion or endothelial-specific deletion of GPR124 in mice results in embryonic lethality associated with abnormal angiogenesis of the forebrain and spinal cord. Expression of GPR124 was found to be required for invasion and migration of blood vessels into neuroepithelium, establishment of BBB properties, and expansion of the cerebral cortex. Thus, GPR124 is an important regulator of neurovasculature development and a potential drug target for cerebrovascular diseases.
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Affiliation(s)
- Mike Cullen
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
| | - Mohammed K. Elzarrad
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
| | - Steven Seaman
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
| | - Enrique Zudaire
- Angiogenesis Core Facility, National Cancer Institute, National Institutes of Health, Gaithersburg, MD, 20877
| | - Janine Stevens
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
| | - Mi Young Yang
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
| | - Xiujie Li
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
| | - Amit Chaudhary
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
| | - Lihong Xu
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
| | - Mary Beth Hilton
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
- Basic Research Program
| | | | - Emily Hsiao
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
| | - Erica V. Stein
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
| | - Frank Cuttitta
- Angiogenesis Core Facility, National Cancer Institute, National Institutes of Health, Gaithersburg, MD, 20877
| | - Diana C. Haines
- Veterinary Pathology Section, Pathology/Histotechnology Laboratory, and
| | - Kunio Nagashima
- Image Analysis Laboratory, Advanced Technology Program, Science Applications International Corporation (SAIC), National Cancer Institute, Frederick, MD 21702; and
| | - Lino Tessarollo
- Neural Development Section, Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
| | - Brad St. Croix
- Tumor Angiogenesis Section, Mouse Cancer Genetics Program, National Cancer Institute, National Institutes of Health, Frederick, MD 21702
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232
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Angiogenic sprouting into neural tissue requires Gpr124, an orphan G protein-coupled receptor. Proc Natl Acad Sci U S A 2011; 108:2807-12. [PMID: 21282641 DOI: 10.1073/pnas.1019761108] [Citation(s) in RCA: 114] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
The vasculature of the CNS is structurally and functionally distinct from that of other organ systems and is particularly prone to developmental abnormalities and hemorrhage. Although other embryonic tissues undergo primary vascularization, the developing nervous system is unique in that it is secondarily vascularized by sprouting angiogenesis from a surrounding perineural plexus. This sprouting angiogenesis requires the TGF-β and Wnt pathways because ablation of these pathways results in aberrant sprouting and hemorrhage. We have genetically deleted Gpr124, a member of the large family of long N-terminal group B G protein-coupled receptors, few members of which have identified ligands or well-defined biologic functions in mammals. We show that, in the developing CNS, Gpr124 is specifically expressed in the vasculature and is absolutely required for proper angiogenic sprouting into the developing neural tube. Embryos lacking Gpr124 exhibit vascular defects characterized by delayed vascular penetration, formation of pathological glomeruloid tufts within the CNS, and hemorrhage. In addition, they display defects in palate and lung development, two processes in which TGF-β and/or Wnt pathways also play important roles. We also show that TGF-β stimulates Gpr124 expression, and ablation of Gpr124 results in perturbed TGF-β pathway activation, suggesting roles for Gpr124 in modulating TGF-β signaling. These results represent a unique function attributed to a long N-terminal group B-type G protein-coupled receptor in a mammalian system.
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