251
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Evidence for the coevolution of axon guidance molecule Netrin and its receptor Frazzled. Gene 2014; 544:25-31. [DOI: 10.1016/j.gene.2014.04.029] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 04/14/2014] [Accepted: 04/16/2014] [Indexed: 11/24/2022]
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252
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Repunte-Canonigo V, Lefebvre C, George O, Kawamura T, Morales M, Koob GF, Califano A, Masliah E, Sanna PP. Gene expression changes consistent with neuroAIDS and impaired working memory in HIV-1 transgenic rats. Mol Neurodegener 2014; 9:26. [PMID: 24980976 PMCID: PMC4107468 DOI: 10.1186/1750-1326-9-26] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2014] [Accepted: 06/19/2014] [Indexed: 01/01/2023] Open
Abstract
BACKGROUND A thorough investigation of the neurobiology of HIV-induced neuronal dysfunction and its evolving phenotype in the setting of viral suppression has been limited by the lack of validated small animal models to probe the effects of concomitant low level expression of multiple HIV-1 products in disease-relevant cells in the CNS. RESULTS We report the results of gene expression profiling of the hippocampus of HIV-1 Tg rats, a rodent model of HIV infection in which multiple HIV-1 proteins are expressed under the control of the viral LTR promoter in disease-relevant cells including microglia and astrocytes. The Gene Set Enrichment Analysis (GSEA) algorithm was used for pathway analysis. Gene expression changes observed are consistent with astrogliosis and microgliosis and include evidence of inflammation and cell proliferation. Among the genes with increased expression in HIV-1 Tg rats was the interferon stimulated gene 15 (ISG-15), which was previously shown to be increased in the cerebrospinal fluid (CSF) of HIV patients and to correlate with neuropsychological impairment and neuropathology, and prostaglandin D2 (PGD2) synthase (Ptgds), which has been associated with immune activation and the induction of astrogliosis and microgliosis. GSEA-based pathway analysis highlighted a broad dysregulation of genes involved in neuronal trophism and neurodegenerative disorders. Among the latter are genesets associated with Huntington's disease, Parkinson's disease, mitochondrial, peroxisome function, and synaptic trophism and plasticity, such as IGF, ErbB and netrin signaling and the PI3K signal transduction pathway, a mediator of neural plasticity and of a vast array of trophic signals. Additionally, gene expression analyses also show altered lipid metabolism and peroxisomes dysfunction. Supporting the functional significance of these gene expression alterations, HIV-1 Tg rats showed working memory impairments in spontaneous alternation behavior in the T-Maze, a paradigm sensitive to prefrontal cortex and hippocampal function. CONCLUSIONS Altogether, differentially regulated genes and pathway analysis identify specific pathways that can be targeted therapeutically to increase trophic support, e.g. IGF, ErbB and netrin signaling, and reduce neuroinflammation, e.g. PGD2 synthesis, which may be beneficial in the treatment of chronic forms of HIV-associated neurocognitive disorders in the setting of viral suppression.
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Affiliation(s)
| | | | | | | | | | | | | | | | - Pietro Paolo Sanna
- Molecular and Cellular Neuroscience Department, La Jolla, CA 92037, USA.
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253
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Gupta GD, Dey G, MG S, Ramalingam B, Shameer K, Thottacherry JJ, Kalappurakkal JM, Howes MT, Chandran R, Das A, Menon S, Parton RG, Sowdhamini R, Thattai M, Mayor S. Population distribution analyses reveal a hierarchy of molecular players underlying parallel endocytic pathways. PLoS One 2014; 9:e100554. [PMID: 24971745 PMCID: PMC4074053 DOI: 10.1371/journal.pone.0100554] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2013] [Accepted: 05/28/2014] [Indexed: 12/11/2022] Open
Abstract
Single-cell-resolved measurements reveal heterogeneous distributions of clathrin-dependent (CD) and -independent (CLIC/GEEC: CG) endocytic activity in Drosophila cell populations. dsRNA-mediated knockdown of core versus peripheral endocytic machinery induces strong changes in the mean, or subtle changes in the shapes of these distributions, respectively. By quantifying these subtle shape changes for 27 single-cell features which report on endocytic activity and cell morphology, we organize 1072 Drosophila genes into a tree-like hierarchy. We find that tree nodes contain gene sets enriched in functional classes and protein complexes, providing a portrait of core and peripheral control of CD and CG endocytosis. For 470 genes we obtain additional features from separate assays and classify them into early- or late-acting genes of the endocytic pathways. Detailed analyses of specific genes at intermediate levels of the tree suggest that Vacuolar ATPase and lysosomal genes involved in vacuolar biogenesis play an evolutionarily conserved role in CG endocytosis.
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Affiliation(s)
- Gagan D. Gupta
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Gautam Dey
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Swetha MG
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Balaji Ramalingam
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Khader Shameer
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Joseph Jose Thottacherry
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Joseph Mathew Kalappurakkal
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Mark T. Howes
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - Ruma Chandran
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Anupam Das
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Sindhu Menon
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Robert G. Parton
- The University of Queensland, Institute for Molecular Bioscience, Queensland, Australia
| | - R. Sowdhamini
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Mukund Thattai
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
| | - Satyajit Mayor
- National Centre for Biological Sciences, Tata Institute of Fundamental Research, UAS/GKVK Campus, Bangalore, India
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254
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Lee SJ, Jung YH, Oh SY, Yong MS, Ryu JM, Han HJ. Netrin-1 induces MMP-12-dependent E-cadherin degradation via the distinct activation of PKCα and FAK/Fyn in promoting mesenchymal stem cell motility. Stem Cells Dev 2014; 23:1870-82. [PMID: 24738865 DOI: 10.1089/scd.2013.0632] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Netrin-1 (Ntn-1) is a potent inducer of neuronal cell migration; however, its molecular mechanism that guides the migratory behavior of stem cells has not been characterized. In this study, we investigate the role of Ntn-1 in promoting the motility of human umbilical cord blood-derived mesenchymal stem cells (UCB-MSCs) and its related signaling pathways. Ntn-1 (50 ng/mL) significantly increased motility of UCB-MSCs, which was inhibited by blocking antibodies for deleted in colorectal cancer (DCC) and integrin (IN) α6β4. Ntn-1 in DCC stimulated protein kinase Cα (PKCα) activation, but not PKCɛ, PKCθ, and PKCζ, while Ntn-1 in INα6β4 induced the phosphorylation of focal adhesion kinase (FAK) and Fyn. Notably, Ntn-1 induced phosphorylation of extracellular signal-regulated kinases (ERK), c-Jun N-terminal kinases (JNK), and nuclear factor kappa-B (NF-κB), but they were concurrently downregulated by blocking the activities of PKCα, FAK, and Fyn. Ntn-1 uniquely increased the MMP-12 expression of all the matrix metalloproteinase (MMP) isoforms present in UCB-MSCs, though this was significantly blocked by an NF-κB inhibitor. Finally, Ntn-1 induced the MMP-12-dependent degradation of E-cadherin (E-cad), while Ntn-1 abrogated the interaction between E-cad and p120-catenin. In addition, Ntn-1 has the ability to stimulate cytoskeletal reorganization-related proteins, such as Cdc42, Rac1, Profilin-1, Cofilin-1, α-Actinin-4, and filamentous actin (F-actin) in UCB-MSCs. These results demonstrate that Ntn-1 induces MMP-12-dependent E-cad degradation via the distinct activation of PKCα and FAK/Fyn, which is necessary to govern the activation of ERK, JNK, and NF-κB in promoting motility of UCB-MSCs.
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Affiliation(s)
- Sei-Jung Lee
- 1 Department of Veterinary Physiology, Research Institute for Veterinary Science, College of Veterinary Medicine, Seoul National University , Seoul, Korea
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255
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Guidance cue netrin-1 and the regulation of inflammation in acute and chronic kidney disease. Mediators Inflamm 2014; 2014:525891. [PMID: 24991088 PMCID: PMC4065723 DOI: 10.1155/2014/525891] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2014] [Revised: 05/01/2014] [Accepted: 05/12/2014] [Indexed: 01/21/2023] Open
Abstract
Acute kidney injury (AKI) is a common problem in the hospital setting and intensive care unit. Despite improved understanding, there are no effective therapies available to treat AKI. A large body of evidence strongly suggests that ischemia reperfusion injury is an inflammatory disease mediated by both adaptive and innate immune systems. Cell migration also plays an important role in embryonic development and inflammation, and this process is highly regulated to ensure tissue homeostasis. One such paradigm exists in the developing nervous system, where neuronal migration is mediated by a balance between chemoattractive and chemorepulsive signals. The ability of the guidance molecule netrin-1 to repulse or abolish attraction of neuronal cells expressing the UNC5B receptor makes it an attractive candidate for the regulation of inflammatory cell migration. Recent identification of netrin-1 as regulators of immune cell migration has led to a large number of studies looking into how netrin-1 controls inflammation and inflammatory cell migration. This review will focus on recent advances in understanding netrin-1 mediated regulation of inflammation during acute and chronic kidney disease and whether netrin-1 and its receptor activation can be used to treat acute and chronic kidney disease.
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256
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Pagella P, Jiménez-Rojo L, Mitsiadis TA. Roles of innervation in developing and regenerating orofacial tissues. Cell Mol Life Sci 2014; 71:2241-51. [PMID: 24395053 PMCID: PMC11113802 DOI: 10.1007/s00018-013-1549-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Revised: 12/16/2013] [Accepted: 12/19/2013] [Indexed: 01/01/2023]
Abstract
The head is innervated by 12 cranial nerves (I-XII) that regulate its sensory and motor functions. Cranial nerves are composed of sensory, motor, or mixed neuronal populations. Sensory neurons perceive generally somatic sensations such as pressure, pain, and temperature. These neurons are also involved in smell, vision, taste, and hearing. Motor neurons ensure the motility of all muscles and glands. Innervation plays an essential role in the development of the various orofacial structures during embryogenesis. Hypoplastic cranial nerves often lead to abnormal development of their target organs and tissues. For example, Möbius syndrome is a congenital disease characterized by defective innervation (i.e., abducens (VI) and facial (VII) nerves), deafness, tooth anomalies, and cleft palate. Hence, it is obvious that the peripheral nervous system is needed for both development and function of orofacial structures. Nerves have a limited capacity to regenerate. However, neural stem cells, which could be used as sources for neural tissue maintenance and repair, have been found in adult neuronal tissues. Similarly, various adult stem cell populations have been isolated from almost all organs of the human body. Stem cells are tightly regulated by their microenvironment, the stem cell niche. Deregulation of adult stem cell behavior results in the development of pathologies such as tumor formation or early tissue senescence. It is thus essential to understand the factors that regulate the functions and maintenance of stem cells. Yet, the potential importance of innervation in the regulation of stem cells and/or their niches in most organs and tissues is largely unexplored. This review focuses on the potential role of innervation in the development and homeostasis of orofacial structures and discusses its possible association with stem cell populations during tissue repair.
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Affiliation(s)
- Pierfrancesco Pagella
- Faculty of Medicine, Institute of Oral Biology, ZZM, University of Zurich, Plattenstrasse 11, 8032 Zurich, Switzerland
| | - Lucia Jiménez-Rojo
- Faculty of Medicine, Institute of Oral Biology, ZZM, University of Zurich, Plattenstrasse 11, 8032 Zurich, Switzerland
| | - Thimios A. Mitsiadis
- Faculty of Medicine, Institute of Oral Biology, ZZM, University of Zurich, Plattenstrasse 11, 8032 Zurich, Switzerland
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257
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Ding Q, Liao SJ, Yu J. Axon guidance factor netrin-1 and its receptors regulate angiogenesis after cerebral ischemia. Neurosci Bull 2014; 30:683-91. [PMID: 24875332 DOI: 10.1007/s12264-013-1441-9] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2013] [Accepted: 01/11/2014] [Indexed: 12/17/2022] Open
Abstract
Neurogenesis and angiogenesis play important roles in functional recovery after ischemic stroke. When cerebral ischemia occurs, axon regeneration can compensate for the loss of apoptotic neurons in the ischemic area. The formation of new blood vessels ameliorates the local decrease in blood supply, enhancing the supply of oxygen and nutrients to newly-formed neurons. New blood vessels also act as a scaffold for the migration of neuroblasts to the infarct area after ischemic stroke. In light of this, researchers have been actively searching for methods to treat cerebral infarction. Netrins were first identified as a family of proteins that mediate axon guidance and direct axon migration during embryogenesis. Later studies have revealed other functions of this protein family. In this review, we focus on netrin-1, which has been shown to be involved in axon migration and angiogenesis, which are required for recovery after cerebral ischemia. Thus, therapies targeting netrin-1 may be useful for the treatment of ischemic stroke.
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Affiliation(s)
- Qiao Ding
- Department of Neurology, Guangdong Key Laboratory for Diagnosis and Treatment of Major Neurological Diseases, National Key Clinical Department, National Key Discipline, the First Affiliated Hospital of Sun Yat-Sen University, Guangzhou, 510080, China
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258
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Ranganathan P, Jayakumar C, Mohamed R, Weintraub NL, Ramesh G. Semaphorin 3A inactivation suppresses ischemia-reperfusion-induced inflammation and acute kidney injury. Am J Physiol Renal Physiol 2014; 307:F183-94. [PMID: 24829504 DOI: 10.1152/ajprenal.00177.2014] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Recent studies show that guidance molecules that are known to regulate cell migration during development may also play an important role in adult pathophysiologic states. One such molecule, semaphorin3A (sema3A), is highly expressed after acute kidney injury (AKI) in mice and humans, but its pathophysiological role is unknown. Genetic inactivation of sema3A protected mice from ischemia-reperfusion-induced AKI, improved tissue histology, reduced neutrophil infiltration, prevented epithelial cell apoptosis, and increased cytokine and chemokine excretion in urine. Pharmacological-based inhibition of sema3A receptor binding likewise protected against ischemia-reperfusion-induced AKI. In vitro, sema3A enhanced toll-like receptor 4-mediated inflammation in epithelial cells, macrophages, and dendritic cells. Moreover, administration of sema3A-treated, bone marrow-derived dendritic cells exacerbated kidney injury. Finally, sema3A augmented cisplatin-induced apoptosis in kidney epithelial cells in vitro via expression of DFFA-like effector a (cidea). Our data suggest that the guidance molecule sema3A exacerbates AKI via promoting inflammation and epithelial cell apoptosis.
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Affiliation(s)
- Punithavathi Ranganathan
- Department of Medicine and Vascular Biology Center, Georgia Regents University, Augusta, Georgia
| | - Calpurnia Jayakumar
- Department of Medicine and Vascular Biology Center, Georgia Regents University, Augusta, Georgia
| | - Riyaz Mohamed
- Department of Medicine and Vascular Biology Center, Georgia Regents University, Augusta, Georgia
| | - Neal L Weintraub
- Department of Medicine and Vascular Biology Center, Georgia Regents University, Augusta, Georgia
| | - Ganesan Ramesh
- Department of Medicine and Vascular Biology Center, Georgia Regents University, Augusta, Georgia
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259
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Yang Y, Lee WS, Tang X, Wadsworth WG. Extracellular matrix regulates UNC-6 (netrin) axon guidance by controlling the direction of intracellular UNC-40 (DCC) outgrowth activity. PLoS One 2014; 9:e97258. [PMID: 24824544 PMCID: PMC4019552 DOI: 10.1371/journal.pone.0097258] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2014] [Accepted: 04/16/2014] [Indexed: 11/18/2022] Open
Abstract
How extracellular molecules influence the direction of axon guidance is poorly understood. The HSN axon of Caenorhabditis elegans is guided towards a ventral source of secreted UNC-6 (netrin). The axon's outgrowth response to UNC-6 is mediated by the UNC-40 (DCC) receptor. We have proposed that in response to the UNC-6 molecule the direction of UNC-40-mediated axon outgrowth is stochastically determined. The direction of guidance is controlled by asymmetric cues, including the gradient of UNC-6, that regulate the probability that UNC-40-mediated axon outgrowth is directed on average, over time, in a specific direction. Here we provide genetic evidence that a specialized extracellular matrix, which lies ventral to the HSN cell body, regulates the probability that UNC-40-mediated axon outgrowth will be directed ventrally towards the matrix. We show that mutations that disrupt the function of proteins associated with this matrix, UNC-52 (perlecan), UNC-112 (kindlin), VAB-19 (Kank), and UNC-97 (PINCH), decrease the probability of UNC-40-mediated axon outgrowth in the ventral direction, while increasing the probability of outgrowth in the anterior and posterior directions. Other results suggest that INA-1 (α integrin) and MIG-15 (NIK kinase) signaling mediate the response in HSN. Although the AVM axon also migrates through this matrix, the mutations have little effect on the direction of AVM axon outgrowth, indicating that responses to the matrix are cell-specific. Together, these results suggest that an extracellular matrix can regulate the direction of UNC-6 guidance by increasing the probability that UNC-40-mediated axon outgrowth activity will be oriented in a specific direction.
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Affiliation(s)
- Yong Yang
- Department of Pathology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
| | - Won Suk Lee
- Department of Pathology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
| | - Xia Tang
- Department of Pathology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
| | - William G. Wadsworth
- Department of Pathology, Rutgers Robert Wood Johnson Medical School, Piscataway, New Jersey, United States of America
- * E-mail:
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260
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Akino T, Han X, Nakayama H, McNeish B, Zurakowski D, Mammoto A, Klagsbrun M, Smith E. Netrin-1 promotes medulloblastoma cell invasiveness and angiogenesis, and demonstrates elevated expression in tumor tissue and urine of patients with pediatric medulloblastoma. Cancer Res 2014; 74:3716-26. [PMID: 24812271 DOI: 10.1158/0008-5472.can-13-3116] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Invasion and dissemination of medulloblastoma within the central nervous system is the principal factor predicting medulloblastoma treatment failure and death. Netrin-1 is an axon guidance factor implicated in tumor and vascular biology, including in invasive behaviors. We found that exogenous netrin-1 stimulated invasion of human medulloblastoma cells and endothelial cells in contrast to VEGF-A, which promoted invasion of endothelial cells but not medulloblastoma cells. Furthermore, medulloblastoma cells expressed endogenous netrin-1 along with its receptors, neogenin and UNC5B. Blockades in endogenous netrin-1, neogenin, or UNC5B reduced medulloblastoma invasiveness. Neogenin blockade inhibited netrin-1-induced endothelial cells tube formation and recruitment of endothelial cells into Matrigel plugs, two hallmarks of angiogenesis. In patients with pediatric medulloblastoma, netrin-1 mRNA levels were increased 1.7-fold in medulloblastoma tumor specimens compared with control specimens from the same patient. Immunohistochemical analyses showed that netrin-1 was elevated in medulloblastoma tumors versus cerebellum controls. Notably, urinary levels of netrin-1 were 9-fold higher in patients with medulloblastoma compared with control individuals. Moreover, urinary netrin-1 levels were higher in patients with invasive medulloblastoma compared with patients with noninvasive medulloblastoma. Finally, we noted that urinary netrin-1 levels diminished after medulloblastoma resection in patients. Our results suggest netrin-1 is a candidate biomarker capable of detecting an invasive, disseminated phenotype in patients with medulloblastoma and predicting their disease status.
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Affiliation(s)
- Tomoshige Akino
- Authors' Affiliations: Vascular Biology Program; Departments of Surgery
| | - Xuezhe Han
- Authors' Affiliations: Vascular Biology Program; Departments of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; and Department of Neurosurgery, the Fourth Affiliated Hospital of Harbin Medical University, Harbin, PR China
| | - Hironao Nakayama
- Authors' Affiliations: Vascular Biology Program; Departments of Surgery
| | - Brendan McNeish
- Authors' Affiliations: Vascular Biology Program; Departments of Surgery
| | | | - Akiko Mammoto
- Authors' Affiliations: Vascular Biology Program; Departments of Surgery
| | - Michael Klagsbrun
- Authors' Affiliations: Vascular Biology Program; Departments of Surgery, Pathology,
| | - Edward Smith
- Authors' Affiliations: Vascular Biology Program; Departments of Neurosurgery, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts; and
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261
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Fothergill T, Donahoo ALS, Douglass A, Zalucki O, Yuan J, Shu T, Goodhill GJ, Richards LJ. Netrin-DCC signaling regulates corpus callosum formation through attraction of pioneering axons and by modulating Slit2-mediated repulsion. Cereb Cortex 2014; 24:1138-51. [PMID: 23302812 DOI: 10.1093/cercor/bhs395] [Citation(s) in RCA: 71] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
The left and right sides of the nervous system communicate via commissural axons that cross the midline during development using evolutionarily conserved molecules. These guidance cues have been particularly well studied in the mammalian spinal cord, but it remains unclear whether these guidance mechanisms for commissural axons are similar in the developing forebrain, in particular for the corpus callosum, the largest and most important commissure for cortical function. Here, we show that Netrin1 initially attracts callosal pioneering axons derived from the cingulate cortex, but surprisingly is not attractive for the neocortical callosal axons that make up the bulk of the projection. Instead, we show that Netrin-deleted in colorectal cancer signaling acts in a fundamentally different manner, to prevent the Slit2-mediated repulsion of precrossing axons thereby allowing them to approach and cross the midline. These results provide the first evidence for how callosal axons integrate multiple guidance cues to navigate the midline.
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MESH Headings
- Animals
- Animals, Newborn
- Axons/physiology
- Cells, Cultured
- Cerebral Cortex/cytology
- Coculture Techniques
- Corpus Callosum/physiology
- DCC Receptor
- Embryo, Mammalian
- Female
- Functional Laterality/genetics
- Functional Laterality/physiology
- Humans
- In Vitro Techniques
- Intercellular Signaling Peptides and Proteins/metabolism
- Male
- Mice, Inbred C57BL
- Mice, Neurologic Mutants
- Nerve Growth Factors/genetics
- Nerve Growth Factors/metabolism
- Nerve Tissue Proteins/genetics
- Nerve Tissue Proteins/metabolism
- Netrin-1
- Pregnancy
- Rats, Wistar
- Receptors, Cell Surface/genetics
- Receptors, Cell Surface/metabolism
- Receptors, Immunologic/genetics
- Receptors, Immunologic/metabolism
- Signal Transduction/genetics
- Signal Transduction/physiology
- Tumor Suppressor Proteins/genetics
- Tumor Suppressor Proteins/metabolism
- Roundabout Proteins
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Affiliation(s)
- Thomas Fothergill
- The University of Queensland, Queensland Brain Institute, Brisbane, Qld., Australia
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262
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263
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Huang F, Ben Aissa M, Magron A, Huard CC, Godin C, Lévesque G, Carreau M. The Fanconi anemia group C protein interacts with uncoordinated 5A and delays apoptosis. PLoS One 2014; 9:e92811. [PMID: 24676280 PMCID: PMC3968024 DOI: 10.1371/journal.pone.0092811] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 02/25/2014] [Indexed: 11/19/2022] Open
Abstract
The Fanconi anemia group C protein (FANCC) is one of the several proteins that comprise the Fanconi anemia (FA) network involved in genomic surveillance. FANCC is mainly cytoplasmic and has many functions, including apoptosis suppression through caspase-mediated proteolytic processing. Here, we examined the role of FANCC proteolytic fragments by identifying their binding partners. We performed a yeast two-hybrid screen with caspase-mediated FANCC cleavage products and identified the dependence receptor uncoordinated-5A (UNC5A) protein. Here, we show that FANCC physically interacts with UNC5A, a pro-apoptotic dependence receptor. FANCC interaction occurs through the UNC5A intracellular domain, specifically via its death domain. FANCC modulates cell sensitivity to UNC5A-mediated apoptosis; we observed reduced UNC5A-mediated apoptosis in the presence of FANCC and increased apoptosis in FANCC-depleted cells. Our results show that FANCC interferes with UNC5A's functions in apoptosis and suggest that FANCC may participate in developmental processes through association with the dependence receptor UNC5A.
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Affiliation(s)
- FengFei Huang
- Department of Pediatrics, Centre Hospitalier Universitaire de Québec, Québec, Québec, Canada
| | - Manel Ben Aissa
- Department of Pediatrics, Centre Hospitalier Universitaire de Québec, Québec, Québec, Canada
| | - Audrey Magron
- Department of Pediatrics, Centre Hospitalier Universitaire de Québec, Québec, Québec, Canada
| | - Caroline C. Huard
- Department of Pediatrics, Centre Hospitalier Universitaire de Québec, Québec, Québec, Canada
| | - Chantal Godin
- Department of Psychiatry and Neurosciences, Université Laval, Cité Universitaire, Québec, Canada
| | - Georges Lévesque
- Department of Psychiatry and Neurosciences, Université Laval, Cité Universitaire, Québec, Canada
| | - Madeleine Carreau
- Department of Pediatrics, Centre Hospitalier Universitaire de Québec, Québec, Québec, Canada
- * E-mail:
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264
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Wang Z, Chi Q, Sherwood DR. MIG-10 (lamellipodin) has netrin-independent functions and is a FOS-1A transcriptional target during anchor cell invasion in C. elegans. Development 2014; 141:1342-53. [PMID: 24553288 PMCID: PMC3943185 DOI: 10.1242/dev.102434] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Accepted: 01/09/2014] [Indexed: 02/04/2023]
Abstract
To transmigrate basement membrane, cells must coordinate distinct signaling activities to breach and pass through this dense extracellular matrix barrier. Netrin expression and activity are strongly associated with invasion in developmental and pathological processes, but how netrin signaling is coordinated with other pathways during invasion is poorly understood. Using the model of anchor cell (AC) invasion in C. elegans, we have previously shown that the integrin receptor heterodimer INA-1/PAT-3 promotes netrin receptor UNC-40 (DCC) localization to the invasive cell membrane of the AC. UNC-6 (netrin)/UNC-40 interactions generate an invasive protrusion that crosses the basement membrane. To understand how UNC-40 signals during invasion, we have used genetic, site of action and live-cell imaging studies to examine the roles of known effectors of UNC-40 signaling in axon outgrowth during AC invasion. UNC-34 (Ena/VASP), the Rac GTPases MIG-2 and CED-10 and the actin binding protein UNC-115 (abLIM) are dedicated UNC-40 effectors that are recruited to the invasive membrane by UNC-40 and generate F-actin. MIG-10 (lamellipodin), an effector of UNC-40 in neurons, however, has independent functions from UNC-6/UNC-40. Furthermore, unlike other UNC-40 effectors, its expression is regulated by FOS-1A, a transcription factor that promotes basement membrane breaching. Similar to UNC-40, however, MIG-10 localization to the invasive cell membrane is also dependent on the integrin INA-1/PAT-3. These studies indicate that MIG-10 has distinct functions from UNC-40 signaling in cell invasion, and demonstrate that integrin coordinates invasion by localizing these molecules to the cell-basement membrane interface.
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Affiliation(s)
- Zheng Wang
- Department of Biology, Duke University, Science Drive, Box 90388, Durham, NC 27708, USA
| | - Qiuyi Chi
- Department of Biology, Duke University, Science Drive, Box 90388, Durham, NC 27708, USA
| | - David R. Sherwood
- Department of Biology, Duke University, Science Drive, Box 90388, Durham, NC 27708, USA
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265
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Branch management: mechanisms of axon branching in the developing vertebrate CNS. Nat Rev Neurosci 2014; 15:7-18. [PMID: 24356070 DOI: 10.1038/nrn3650] [Citation(s) in RCA: 190] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The remarkable ability of a single axon to extend multiple branches and form terminal arbors enables vertebrate neurons to integrate information from divergent regions of the nervous system. Axons select appropriate pathways during development, but it is the branches that extend interstitially from the axon shaft and arborize at specific targets that are responsible for virtually all of the synaptic connectivity in the vertebrate CNS. How do axons form branches at specific target regions? Recent studies have identified molecular cues that activate intracellular signalling pathways in axons and mediate dynamic reorganization of the cytoskeleton to promote the formation of axon branches.
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266
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Haddick PCG, Tom I, Luis E, Quiñones G, Wranik BJ, Ramani SR, Stephan JP, Tessier-Lavigne M, Gonzalez LC. Defining the ligand specificity of the deleted in colorectal cancer (DCC) receptor. PLoS One 2014; 9:e84823. [PMID: 24400119 PMCID: PMC3882260 DOI: 10.1371/journal.pone.0084823] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2013] [Accepted: 11/20/2013] [Indexed: 11/23/2022] Open
Abstract
The growth and guidance of many axons in the developing nervous system require Netrin-mediated activation of Deleted in Colorectal Cancer (DCC) and other still unknown signaling cues. Commissural axon guidance defects are more severe in DCC mutant mice than Netrin-1 mutant mice, suggesting additional DCC activating signals besides Netrin-1 are involved in proper axon growth. Here we report that interaction screens on extracellular protein microarrays representing over 1,000 proteins uniquely identified Cerebellin 4 (CBLN4), a member of the C1q-tumor necrosis factor (TNF) family, and Netrin-1 as extracellular DCC-binding partners. Immunofluorescence and radio-ligand binding studies demonstrate that Netrin-1 competes with CBLN4 binding at an overlapping site within the membrane-proximal fibronectin domains (FN) 4–6 of DCC and binds with ∼5-fold higher affinity. CBLN4 also binds to the DCC homolog, Neogenin-1 (NEO1), but with a lower affinity compared to DCC. CBLN4-null mice did not show a defect in commissural axons of the developing spinal cord but did display a transient increase in the number of wandering axons in the brachial plexus, consistent with a role in axon guidance. Overall, the data solidifies CBLN4 as a bona fide DCC ligand and strengthens its implication in axon guidance.
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Affiliation(s)
- Patrick C. G. Haddick
- Department of Neuroscience, Genentech, South San Francisco, California, United States of America
| | - Irene Tom
- Department of Protein Chemistry, Genentech, South San Francisco, California, United States of America
| | - Elizabeth Luis
- Department of Protein Chemistry, Genentech, South San Francisco, California, United States of America
| | - Gabriel Quiñones
- Department of Protein Chemistry, Genentech, South San Francisco, California, United States of America
| | - Bernd J. Wranik
- Department of Protein Chemistry, Genentech, South San Francisco, California, United States of America
| | - Sree R. Ramani
- Department of Protein Chemistry, Genentech, South San Francisco, California, United States of America
| | - Jean-Philippe Stephan
- Department of Protein Chemistry, Genentech, South San Francisco, California, United States of America
| | - Marc Tessier-Lavigne
- Department of Neuroscience, Genentech, South San Francisco, California, United States of America
| | - Lino C. Gonzalez
- Department of Protein Chemistry, Genentech, South San Francisco, California, United States of America
- * E-mail:
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267
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Maintaining and modifying connections: roles for axon guidance cues in the mature nervous system. Neuropsychopharmacology 2014; 39:246-7. [PMID: 24317322 PMCID: PMC3857654 DOI: 10.1038/npp.2013.212] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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268
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Netrin-1 promotes excitatory synaptogenesis between cortical neurons by initiating synapse assembly. J Neurosci 2013; 33:17278-89. [PMID: 24174661 DOI: 10.1523/jneurosci.1085-13.2013] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Netrin-1 is a secreted protein that directs long-range axon guidance during early stages of neural circuit formation and continues to be expressed in the mammalian forebrain during the postnatal period of peak synapse formation. Here we demonstrate a synaptogenic function of netrin-1 in rat and mouse cortical neurons and investigate the underlying mechanism. We report that netrin-1 and its receptor DCC are widely expressed by neurons in the developing mammalian cortex during synapse formation and are enriched at synapses in vivo. We detect DCC protein distributed along the axons and dendrites of cultured cortical neurons and provide evidence that newly translated netrin-1 is selectively transported to dendrites. Using gain and loss of function manipulations, we demonstrate that netrin-1 increases the number and strength of excitatory synapses made between developing cortical neurons. We show that netrin-1 increases the complexity of axon and dendrite arbors, thereby increasing the probability of contact. At sites of contact, netrin-1 promotes adhesion, while locally enriching and reorganizing the underlying actin cytoskeleton through Src family kinase signaling and m-Tor-dependent protein translation to locally cluster presynaptic and postsynaptic proteins. Finally, we demonstrate using whole-cell patch-clamp electrophysiology that netrin-1 increases the frequency and amplitude of mEPSCs recorded from cortical pyramidal neurons. These findings identify netrin-1 as a synapse-enriched protein that promotes synaptogenesis between mammalian cortical neurons.
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269
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Hayashi Y, Yamamoto N, Nakagawa T, Ito J. Insulin-like growth factor 1 induces the transcription of Gap43 and Ntn1 during hair cell protection in the neonatal murine cochlea. Neurosci Lett 2013; 560:7-11. [PMID: 24333914 DOI: 10.1016/j.neulet.2013.11.062] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2013] [Revised: 11/09/2013] [Accepted: 11/29/2013] [Indexed: 01/28/2023]
Abstract
We previously reported that insulin-like growth factor 1 (IGF-1) protects cochlear hair cells against aminoglycosides through activation of the PI3K/Akt and MEK/ERK pathways in supporting cells. In this study, we found that IGF-1 up-regulated the expression levels of Gap43 and Ntn1 as measured using cDNA microarray analysis and qRT-PCR. Using inhibitors of the PI3K/Akt and MEK/ERK pathways, we reveal that both pathways are involved in the up-regulation of Gap43 and Ntn1 expression. Moreover the time window of Gap43 and Ntn1 transcription was limited to within 12h after IGF-1 treatment, indicating that downstream gene expression was tightly controlled by IGF-1.
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Affiliation(s)
- Yushi Hayashi
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Norio Yamamoto
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Takayuki Nakagawa
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
| | - Juichi Ito
- Department of Otolaryngology-Head and Neck Surgery, Graduate School of Medicine, Kyoto University, 54 Shogoin Kawahara-cho, Sakyo-ku, Kyoto 606-8507, Japan.
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270
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O'Leary C, Cole SJ, Langford M, Hewage J, White A, Cooper HM. RGMa regulates cortical interneuron migration and differentiation. PLoS One 2013; 8:e81711. [PMID: 24312340 PMCID: PMC3842424 DOI: 10.1371/journal.pone.0081711] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2013] [Accepted: 10/23/2013] [Indexed: 11/24/2022] Open
Abstract
The etiology of neuropsychiatric disorders, including schizophrenia and autism, has been linked to a failure to establish the intricate neural network comprising excitatory pyramidal and inhibitory interneurons during neocortex development. A large proportion of cortical inhibitory interneurons originate in the medial ganglionic eminence (MGE) of the ventral telencephalon and then migrate through the ventral subventricular zone, across the corticostriatal junction, into the embryonic cortex. Successful navigation of newborn interneurons through the complex environment of the ventral telencephalon is governed by spatiotemporally restricted deployment of both chemorepulsive and chemoattractive guidance cues which work in concert to create a migratory corridor. Despite the expanding list of interneuron guidance cues, cues responsible for preventing interneurons from re-entering the ventricular zone of the ganglionic eminences have not been well characterized. Here we provide evidence that the chemorepulsive axon guidance cue, RGMa (Repulsive Guidance Molecule a), may fulfill this function. The ventricular zone restricted expression of RGMa in the ganglionic eminences and the presence of its receptor, Neogenin, in the ventricular zone and on newborn and maturing MGE-derived interneurons implicates RGMa-Neogenin interactions in interneuron differentiation and migration. Using an in vitro approach, we show that RGMa promotes interneuron differentiation by potentiating neurite outgrowth. In addition, using in vitro explant and migration assays, we provide evidence that RGMa is a repulsive guidance cue for newborn interneurons migrating out of the ganglionic eminence ventricular zone. Intriguingly, the alternative Neogenin ligand, Netrin-1, had no effect on migration. However, we observed complete abrogation of RGMa-induced chemorepulsion when newborn interneurons were simultaneously exposed to RGMa and Netrin-1 gradients, suggesting a novel mechanism for the tight regulation of RGMa-guided interneuron migration. We propose that during peak neurogenesis, repulsive RGMa-Neogenin interactions drive interneurons into the migratory corridor and prevent re-entry into the ventricular zone of the ganglionic eminences.
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Affiliation(s)
- Conor O'Leary
- The University of Queensland, Queensland Brain Institute, Brisbane, Queensland, Australia
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271
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Bongo JB, Peng DQ. The neuroimmune guidance cue netrin-1: a new therapeutic target in cardiovascular disease. J Cardiol 2013; 63:95-8. [PMID: 24262644 DOI: 10.1016/j.jjcc.2013.10.006] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2013] [Revised: 07/30/2013] [Accepted: 10/06/2013] [Indexed: 02/01/2023]
Abstract
Netrins are a family of proteins involved in cell migration and axon guidance during embryogenesis. The different functions and mechanisms of action of this family of proteins have been better characterized with the study of netrin-1. They are chemotropic and act as a bifunctional regulator of neuron migration. Apart from its role in the central nervous system, researchers have proven that netrin-1 plays a role in the development and formation of non-neural tissue; netrin-1 is thereby involved in regulation of cancers, cardiovascular diseases, kidney diseases, and other diseases. Concerning the cardiovascular realm, netrin-1 promotes angiogenesis and accelerates atherosclerosis, protects the heart against ischemia-reperfusion injury, and reduces the infarct size. These findings make the neuroimmune guidance cue netrin-1 an important therapeutic target. This work seeks to review the subject based on studies that have been conducted over the past decade to identify the perspectives and extent of the research on this protein in the field of cardiology.
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Affiliation(s)
- Joseph Bertrand Bongo
- Department of cardiology, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, PR China
| | - Dao Quan Peng
- Department of cardiology, the Second Xiangya Hospital, Central South University, Changsha, Hunan 410011, PR China.
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272
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Netrin-dependent downregulation of Frazzled/DCC is required for the dissociation of the peripodial epithelium in Drosophila. Nat Commun 2013; 4:2790. [DOI: 10.1038/ncomms3790] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 10/17/2013] [Indexed: 01/02/2023] Open
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273
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Harding LB, Schultz IR, Goetz GW, Luckenbach JA, Young G, Goetz FW, Swanson P. High-throughput sequencing and pathway analysis reveal alteration of the pituitary transcriptome by 17α-ethynylestradiol (EE2) in female coho salmon, Oncorhynchus kisutch. AQUATIC TOXICOLOGY (AMSTERDAM, NETHERLANDS) 2013; 142-143:146-163. [PMID: 24007788 DOI: 10.1016/j.aquatox.2013.07.020] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/27/2013] [Revised: 07/26/2013] [Accepted: 07/31/2013] [Indexed: 06/02/2023]
Abstract
Considerable research has been done on the effects of endocrine disrupting chemicals (EDCs) on reproduction and gene expression in the brain, liver and gonads of teleost fish, but information on impacts to the pituitary gland are still limited despite its central role in regulating reproduction. The aim of this study was to further our understanding of the potential effects of natural and synthetic estrogens on the brain-pituitary-gonad axis in fish by determining the effects of 17α-ethynylestradiol (EE2) on the pituitary transcriptome. We exposed sub-adult coho salmon (Oncorhynchus kisutch) to 0 or 12 ng EE2/L for up to 6 weeks and effects on the pituitary transcriptome of females were assessed using high-throughput Illumina(®) sequencing, RNA-Seq and pathway analysis. After 1 or 6 weeks, 218 and 670 contiguous sequences (contigs) respectively, were differentially expressed in pituitaries of EE2-exposed fish relative to control. Two of the most highly up- and down-regulated contigs were luteinizing hormone β subunit (241-fold and 395-fold at 1 and 6 weeks, respectively) and follicle-stimulating hormone β subunit (-3.4-fold at 6 weeks). Additional contigs related to gonadotropin synthesis and release were differentially expressed in EE2-exposed fish relative to controls. These included contigs involved in gonadotropin releasing hormone (GNRH) and transforming growth factor-β signaling. There was an over-representation of significantly affected contigs in 33 and 18 canonical pathways at 1 and 6 weeks, respectively, including circadian rhythm signaling, calcium signaling, peroxisome proliferator-activated receptor (PPAR) signaling, PPARα/retinoid x receptor α activation, and netrin signaling. Network analysis identified potential interactions between genes involved in circadian rhythm and GNRH signaling, suggesting possible effects of EE2 on timing of reproductive events.
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Affiliation(s)
- Louisa B Harding
- School of Aquatic and Fishery Sciences, University of Washington, Seattle, WA 98195, USA
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274
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Ricoult SG, Pla-Roca M, Safavieh R, Lopez-Ayon GM, Grütter P, Kennedy TE, Juncker D. Large dynamic range digital nanodot gradients of biomolecules made by low-cost nanocontact printing for cell haptotaxis. SMALL (WEINHEIM AN DER BERGSTRASSE, GERMANY) 2013; 9:3308-3313. [PMID: 23606620 DOI: 10.1002/smll.201202915] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2012] [Revised: 01/25/2013] [Indexed: 06/02/2023]
Abstract
A novel method is introduced for ultrahigh throughput and ultralow cost patterning of biomolecules with nanometer resolution and novel 2D digital nanodot gradients (DNGs) with mathematically defined slopes are created. The technique is based on lift-off nanocontact printing while using high-resolution photopolymer stamps that are rapidly produced at a low cost through double replication from Si originals. Printed patterns with 100 nm features are shown. DNGs with varying spacing between the dots and a record dynamic range of 4400 are produced; 64 unique DNGs, each with hundreds of thousands of dots, are inked and printed in 5.5 min. The adhesive response and haptotaxis of C2C12 myoblast cells on DNGs demonstrated their biofunctionality. The great flexibility in pattern design, the massive parallel ability, the ultra low cost, and the extreme ease of polymer lift-off nanocontact printing will facilitate its use for various biological and medical applications.
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Affiliation(s)
- Sébastien G Ricoult
- Department of Biomedical Engineering, McGill University and Génome Québec Innovation Centre, McGill University, 740 Dr. Penfield Avenue, Montréal, Québec H3A 0G1, Canada, Fax: (+)1 (514) 398 1790; Webpage: http://wikisites.mcgill.ca/djgroup/; Department of Neuroscience, McGill University, 3801 University Avenue, Montréal, Québec H3A 0G1, Canada
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275
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Dalpe G, Tarsitano M, Persico MG, Zheng H, Culotti J. C. elegans PVF-1 inhibits permissive UNC-40 signalling through CED-10 GTPase to position the male ray 1 sensillum. Development 2013; 140:4020-30. [DOI: 10.1242/dev.095190] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Graded distributions of netrin and semaphorin guidance cues convey instructive polarity information to migrating cells and growth cones, but also have permissive (i.e. non-polarity determining) functions in mammalian development and repair. The permissive functions of these cues are largely uncharacterised at a molecular level. We found previously that UNC-6 (netrin) signals permissively through UNC-40 (DCC) and UNC-5 receptors to prevent anterior displacement of the ray 1 sensillum in the C. elegans male tail. UNC-6/UNC-40 signalling functions in parallel with SMP-1 (semaporin 1)/PLX-1 (plexin) signalling to prevent this defect. Here, we report that a deletion allele of pvf-1, which encodes a VEGF-related protein, causes no ray 1 defects, but enhances ray 1 defects of a plx-1 mutant, and unexpectedly also suppresses unc-6(ev400)-null mutant ray 1 defects. These mutant ray 1 inductive and suppressive effects are mimicked by the ability of unc-40(+) and ced-10(gain-of-function) multi-copy transgene arrays to induce ray 1 defects or suppress unc-6 mutant ray 1 defects, depending on their dosage, suggesting the pvf-1 mutation causes UNC-40 overactivity that interferes with signalling but is partially sensitive to UNC-6. Additional data suggest PVF-1 functions through four VEGF receptor-related proteins and inhibits only CED-10 (a GTPase), but not MIG-2-dependent UNC-40 activity, even though UNC-40 functions through both GTPases to position ray 1. pvf-1 and receptor mutant ray 1 defects are rescued by transgenes expressing mouse VEGF164 and human VEGF receptors, respectively. These data report the first case of VEGF-induced inhibition of the netrin signalling and a molecular conservation of VEGF function from worms to humans.
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Affiliation(s)
- Gratien Dalpe
- Samuel Lunenfeld Research Institute of Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada
| | | | | | - Hong Zheng
- Samuel Lunenfeld Research Institute of Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada
| | - Joseph Culotti
- Samuel Lunenfeld Research Institute of Mount Sinai Hospital, Toronto, Ontario, M5G 1X5, Canada
- Department of Molecular Biology, University of Toronto, Toronto, Ontario, M5S 1SA, Canada
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276
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Gallea C, Popa T, Hubsch C, Valabregue R, Brochard V, Kundu P, Schmitt B, Bardinet E, Bertasi E, Flamand-Roze C, Alexandre N, Delmaire C, Méneret A, Depienne C, Poupon C, Hertz-Pannier L, Cincotta M, Vidailhet M, Lehericy S, Meunier S, Roze E. RAD51 deficiency disrupts the corticospinal lateralization of motor control. Brain 2013; 136:3333-46. [DOI: 10.1093/brain/awt258] [Citation(s) in RCA: 42] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023] Open
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277
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Abstract
PURPOSE OF REVIEW The mechanisms of tolerance induction and maintenance remain incompletely understood and have yet to be translated to clinical practice. Advances in imaging techniques have allowed precise examination of cell interactions in the lymph node, often in real time. Herein we review evidence that lymph node structure is dynamic and controls the character of the immune response in a multistep, multiplayer dance. T-cell responses in particular can be initiated or influenced in regions beyond the canonical T-cell zone. We propose that the cortical ridge is one such region required for induction and maintenance of tolerance. RECENT FINDINGS Lymph node domains are more complex than T-cell and B-cell zones. Different domains are important for different types of immune responses. These domains are in part defined by dynamic, malleable physical structures that guide cell interactions and influence immune outcomes. SUMMARY Further probing as to how lymph node stromal cells and fibers interact with and determine the character of immune responses should yield fundamental insights into tolerance and immunity. Manipulation of lymph node structure and associated unique cell types and molecules may allow therapeutic interventions in the tolerogenic process.
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278
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Poon VY, Choi S, Park M. Growth factors in synaptic function. Front Synaptic Neurosci 2013; 5:6. [PMID: 24065916 PMCID: PMC3776238 DOI: 10.3389/fnsyn.2013.00006] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2013] [Accepted: 08/29/2013] [Indexed: 12/15/2022] Open
Abstract
Synapses are increasingly recognized as key structures that malfunction in disorders like schizophrenia, mental retardation, and neurodegenerative diseases. The importance and complexity of the synapse has fuelled research into the molecular mechanisms underlying synaptogenesis, synaptic transmission, and plasticity. In this regard, neurotrophic factors such as netrin, Wnt, transforming growth factor-β (TGF-β), tumor necrosis factor-α (TNF-α), and others have gained prominence for their ability to regulate synaptic function. Several of these factors were first implicated in neuroprotection, neuronal growth, and axon guidance. However, their roles in synaptic development and function have become increasingly clear, and the downstream signaling pathways employed by these factors have begun to be elucidated. In this review, we will address the role of these factors and their downstream effectors in synaptic function in vivo and in cultured neurons.
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Affiliation(s)
- Vivian Y Poon
- Neuroscience and Behavioral Disorders Program, Duke-NUS Graduate Medical School Singapore, Singapore
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279
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Morrissey MA, Hagedorn EJ, Sherwood DR. Cell invasion through basement membrane: The netrin receptor DCC guides the way. WORM 2013; 2:e26169. [PMID: 24778942 PMCID: PMC3875654 DOI: 10.4161/worm.26169] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2013] [Revised: 08/14/2013] [Accepted: 08/15/2013] [Indexed: 01/23/2023]
Abstract
Cell invasion through basement membrane is an essential part of normal development and physiology, and occurs during the pathological progression of human inflammatory diseases and cancer. F-actin-rich membrane protrusions, called invadopodia, have been hypothesized to be the “drill bits” of invasive cells, mediating invasion through the dense, highly cross-linked basement membrane matrix. Though studied in vitro for over 30 y, invadopodia function in vivo has remained elusive. We have recently discovered that invadopodia breach basement membrane during anchor cell invasion in C. elegans, a genetically and visually tractable in vivo invasion event. Further, we found that the netrin receptor DCC localizes to the initial site of basement membrane breach and directs invasion through a single gap in the matrix. In this commentary, we examine how the dynamics and structure of AC-invadopodia compare with in vitro invadopodia and how the netrin receptor guides invasion through a single basement membrane breach. We end with a discussion of our surprising result that the anchor cell pushes the basement membrane aside, instead of completely dissolving it through proteolysis, and provide some ideas for how proteases and physical displacement may work together to ensure efficient and robust invasion.
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280
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Control of male and female fertility by the netrin axon guidance genes. PLoS One 2013; 8:e72524. [PMID: 23977313 PMCID: PMC3744485 DOI: 10.1371/journal.pone.0072524] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2013] [Accepted: 07/17/2013] [Indexed: 01/29/2023] Open
Abstract
The netrin axon guidance genes have previously been implicated in fertility in C. elegans and in vertebrates. Here we show that adult Drosophila lacking both netrin genes, NetA and NetB, have fertility defects in both sexes together with an inability to fly and reduced viability. NetAB females produce fertilized eggs at a much lower rate than wild type. Oocyte development and ovarian innervation are unaffected in NetAB females, and the reproductive tract appears normal. A small gene, hog, that resides in an intron of NetB does not contribute to the NetAB phenotype. Restoring endogenous NetB expression rescues egg-laying, but additional genetic manipulations, such as restoration of netrin midline expression and inhibition of cell death have no effect on fertility. NetAB males induce reduced egg-laying in wild type females and display mirror movements of their wings during courtship. Measurement of courtship parameters revealed no difference compared to wild type males. Transgenic manipulations failed to rescue male fertility and mirror movements. Additional genetic manipulations, such as removal of the enabled gene, a known suppressor of the NetAB embryonic CNS phenotype, did not improve the behavioral defects. The ability to fly was rescued by inhibition of neuronal cell death and pan-neural NetA expression. Based on our results we hypothesize that the adult fertility defects of NetAB mutants are due to ovulation defects in females and a failure to properly transfer sperm proteins in males, and are likely to involve multiple neural circuits.
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281
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Hagedorn EJ, Ziel JW, Morrissey MA, Linden LM, Wang Z, Chi Q, Johnson SA, Sherwood DR. The netrin receptor DCC focuses invadopodia-driven basement membrane transmigration in vivo. ACTA ACUST UNITED AC 2013; 201:903-13. [PMID: 23751497 PMCID: PMC3678161 DOI: 10.1083/jcb.201301091] [Citation(s) in RCA: 90] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Localized activation of netrin signaling induces focused F-actin formation and the protrusive force necessary for physical displacement of basement membrane during cell transmigration. Though critical to normal development and cancer metastasis, how cells traverse basement membranes is poorly understood. A central impediment has been the challenge of visualizing invasive cell interactions with basement membrane in vivo. By developing live-cell imaging methods to follow anchor cell (AC) invasion in Caenorhabditis elegans, we identify F-actin–based invadopodia that breach basement membrane. When an invadopodium penetrates basement membrane, it rapidly transitions into a stable invasive process that expands the breach and crosses into the vulval tissue. We find that the netrin receptor UNC-40 (DCC) specifically enriches at the site of basement membrane breach and that activation by UNC-6 (netrin) directs focused F-actin formation, generating the invasive protrusion and the cessation of invadopodia. Using optical highlighting of basement membrane components, we further demonstrate that rather than relying solely on proteolytic dissolution, the AC’s protrusion physically displaces basement membrane. These studies reveal an UNC-40–mediated morphogenetic transition at the cell–basement membrane interface that directs invading cells across basement membrane barriers.
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282
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Evsyukova I, Plestant C, Anton ES. Integrative mechanisms of oriented neuronal migration in the developing brain. Annu Rev Cell Dev Biol 2013; 29:299-353. [PMID: 23937349 DOI: 10.1146/annurev-cellbio-101512-122400] [Citation(s) in RCA: 110] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
The emergence of functional neuronal connectivity in the developing cerebral cortex depends on neuronal migration. This process enables appropriate positioning of neurons and the emergence of neuronal identity so that the correct patterns of functional synaptic connectivity between the right types and numbers of neurons can emerge. Delineating the complexities of neuronal migration is critical to our understanding of normal cerebral cortical formation and neurodevelopmental disorders resulting from neuronal migration defects. For the most part, the integrated cell biological basis of the complex behavior of oriented neuronal migration within the developing mammalian cerebral cortex remains an enigma. This review aims to analyze the integrative mechanisms that enable neurons to sense environmental guidance cues and translate them into oriented patterns of migration toward defined areas of the cerebral cortex. We discuss how signals emanating from different domains of neurons get integrated to control distinct aspects of migratory behavior and how different types of cortical neurons coordinate their migratory activities within the developing cerebral cortex to produce functionally critical laminar organization.
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Affiliation(s)
- Irina Evsyukova
- Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599;
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283
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Tian C, Liu J. Repulsive guidance molecules (RGMs) and neogenin in bone morphogenetic protein (BMP) signaling. Mol Reprod Dev 2013; 80:700-17. [PMID: 23740870 DOI: 10.1002/mrd.22199] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2013] [Accepted: 05/28/2013] [Indexed: 02/06/2023]
Abstract
Bone morphogenetic proteins (BMPs) belong to the transforming growth factor-beta (TGFβ) superfamily. BMPs mediate a highly conserved signal transduction cascade through the type-I and type-II serine/threonine kinase receptors and intracellular Smad proteins, which regulate multiple developmental and homeostatic processes. Mutations in this pathway can cause various diseases in humans, such as skeletal disorders, cardiovascular diseases, and various cancers. Multiple levels of regulation, including extracellular regulation, help to ensure proper spatiotemporal control of BMP signaling in the right cellular context. The family of repulsive guidance molecules (RGMs) and the type-I transmembrane protein neogenin, a paralog of DCC (Deleted in Colorectal Cancer), have been implicated in modulating the BMP pathway. In this review, we discuss the properties and functions of RGM proteins and neogenin, focusing on their roles in the modulation of BMP signal transduction.
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Affiliation(s)
- Chenxi Tian
- Department of Molecular Biology and Genetics, Cornell University, Ithaca, New York
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284
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Bell CH, Healey E, van Erp S, Bishop B, Tang C, Gilbert RJ, Aricescu AR, Pasterkamp RJ, Siebold C. Structure of the repulsive guidance molecule (RGM)-neogenin signaling hub. Science 2013; 341:77-80. [PMID: 23744777 PMCID: PMC4730555 DOI: 10.1126/science.1232322] [Citation(s) in RCA: 46] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Repulsive guidance molecule family members (RGMs) control fundamental and diverse cellular processes, including motility and adhesion, immune cell regulation, and systemic iron metabolism. However, it is not known how RGMs initiate signaling through their common cell-surface receptor, neogenin (NEO1). Here, we present crystal structures of the NEO1 RGM-binding region and its complex with human RGMB (also called dragon). The RGMB structure reveals a previously unknown protein fold and a functionally important autocatalytic cleavage mechanism and provides a framework to explain numerous disease-linked mutations in RGMs. In the complex, two RGMB ectodomains conformationally stabilize the juxtamembrane regions of two NEO1 receptors in a pH-dependent manner. We demonstrate that all RGM-NEO1 complexes share this architecture, which therefore represents the core of multiple signaling pathways.
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Affiliation(s)
- Christian H. Bell
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Eleanor Healey
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Susan van Erp
- Department of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, CG Utrecht 3584, Netherlands
| | - Benjamin Bishop
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Chenxiang Tang
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - Robert J.C. Gilbert
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - A. Radu Aricescu
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
| | - R. Jeroen Pasterkamp
- Department of Neuroscience and Pharmacology, Rudolf Magnus Institute of Neuroscience, University Medical Center Utrecht, CG Utrecht 3584, Netherlands
| | - Christian Siebold
- Division of Structural Biology, Wellcome Trust Centre for Human Genetics, University of Oxford, Roosevelt Drive, Oxford OX3 7BN, UK
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285
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Bin JM, Rajasekharan S, Kuhlmann T, Hanes I, Marcal N, Han D, Rodrigues SP, Leong SY, Newcombe J, Antel JP, Kennedy TE. Full-length and fragmented netrin-1 in multiple sclerosis plaques are inhibitors of oligodendrocyte precursor cell migration. THE AMERICAN JOURNAL OF PATHOLOGY 2013; 183:673-80. [PMID: 23831296 DOI: 10.1016/j.ajpath.2013.06.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/07/2013] [Revised: 05/29/2013] [Accepted: 06/03/2013] [Indexed: 10/26/2022]
Abstract
Oligodendrocytes exhibit a limited capacity to remyelinate in multiple sclerosis. Factors present in multiple sclerosis lesions are thought to inhibit oligodendrocyte precursor cell migration, limiting their recruitment to axons requiring remyelination; however, few inhibitors have been identified. A candidate inhibitor is netrin-1, a secreted protein that repels migrating oligodendrocyte precursor cells during neural development and is expressed by myelinating oligodendrocytes in the mature rodent central nervous system. Herein, we examined the distribution of netrin-1 in adult human white matter and multiple sclerosis lesions. We detected full-length netrin-1 protein and shorter netrin-1 fragments in samples of normal white matter and of multiple sclerosis lesions from adult human brain. We demonstrate that peptides corresponding to amino terminal domains VI and V of netrin-1 repel migrating oligodendrocyte precursor cells, but lack the chemoattractant activity of full-length netrin-1. Furthermore, recombinant domains VI-V of netrin-1 disrupt the chemoattractant activity of full-length netrin-1, consistent with a competitive mechanism of action. These findings indicate that full-length and fragmented forms of netrin-1, found in multiple sclerosis lesions, have the capacity to inhibit oligodendrocyte precursor migration, identifying netrin-1 as a potential target for therapies that promote remyelination.
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Affiliation(s)
- Jenea M Bin
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, Montreal, Quebec, Canada
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286
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O'Donnell MP, Bashaw GJ. Distinct functional domains of the Abelson tyrosine kinase control axon guidance responses to Netrin and Slit to regulate the assembly of neural circuits. Development 2013; 140:2724-33. [PMID: 23720041 DOI: 10.1242/dev.093831] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
To develop a functional nervous system, axons must initially navigate through a complex environment, directed by guidance ligands and receptors. These receptors must link to intracellular signaling cascades to direct axon pathfinding decisions. The Abelson tyrosine kinase (Abl) plays a crucial role in multiple Drosophila axon guidance pathways during development, though the mechanism by which Abl elicits a diverse set of guidance outputs is currently unknown. We identified Abl in a genetic screen for genes that contribute to Netrin-dependent axon guidance in midline-crossing (commissural) neurons. We find that Abl interacts both physically and genetically with the Netrin receptor Frazzled, and that disrupting this interaction prevents Abl from promoting midline axon crossing. Moreover, we find that Abl exerts its diverse activities through at least two different mechanisms: (1) a partly kinase-independent, structural function in midline attraction through its C-terminal F-actin binding domain (FABD) and (2) a kinase-dependent inhibition of repulsive guidance pathways that does not require the Abl C terminus. Abl also regulates motor axon pathfinding through a non-overlapping set of functional domains. These results highlight how a multifunctional kinase can trigger diverse axon guidance outcomes through the use of distinct structural motifs.
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Affiliation(s)
- Michael P O'Donnell
- Department of Neuroscience, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA 19104, USA
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287
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Frazzled/DCC facilitates cardiac cell outgrowth and attachment during Drosophila dorsal vessel formation. Dev Biol 2013; 380:233-42. [PMID: 23685255 DOI: 10.1016/j.ydbio.2013.05.007] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2012] [Revised: 04/29/2013] [Accepted: 05/07/2013] [Indexed: 01/30/2023]
Abstract
Drosophila embryonic dorsal vessel (DV) morphogenesis is a highly stereotyped process that involves the migration and morphogenesis of 52 pairs of cardioblasts (CBs) in order to form a linear tube. This process requires spatiotemporally-regulated localization of signaling and adhesive proteins in order to coordinate the formation of a central lumen while maintaining simultaneous adhesion between CBs. Previous studies have shown that the Slit/Roundabout and Netrin/Unc5 repulsive signaling pathways facilitate site-specific loss of adhesion between contralateral CBs in order to form a luminal space. However, the concomitant mechanism by which attraction initiates CB outgrowth and discrete localization of adhesive proteins remains poorly understood. Here we provide genetic evidence that Netrin signals through DCC (Deleted in Colorectal Carcinoma)/UNC-40/Frazzled (Fra) to mediate CB outgrowth and attachment and that this function occurs prior to and independently of Netrin/UNC-5 signaling. fra mRNA is expressed in the CBs prior to and during DV morphogenesis. Loss-of-fra-function results in significant defects in cell shape and alignment between contralateral CB rows. In addition, CB outgrowth and attachment is impaired in both fra loss- and gain-of-function mutants. Deletion of both Netrin genes (NetA and NetB) results in CB attachment phenotypes similar to fra mutants. Similar defects are also seen when both fra and unc5 are deleted. Finally we show that Fra accumulates at dorsal and ventral leading edges of paired CBs, and this localization is dependent upon Netrin. We propose that while repulsive guidance mechanisms contribute to lumen formation by preventing luminal domains from coming together, site-specific Netrin/Frazzled signaling mediates CB attachment.
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288
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Qu C, Dwyer T, Shao Q, Yang T, Huang H, Liu G. Direct binding of TUBB3 with DCC couples netrin-1 signaling to intracellular microtubule dynamics in axon outgrowth and guidance. J Cell Sci 2013; 126:3070-81. [PMID: 23641072 DOI: 10.1242/jcs.122184] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022] Open
Abstract
The coupling of axon guidance cues, such as netrin-1, to microtubule (MT) dynamics is essential for growth cone navigation in the developing nervous system. However, whether axon guidance signaling regulates MT dynamics directly or indirectly is unclear. Here, we report that TUBB3, the most dynamic β-tubulin isoform in neurons, directly interacts with the netrin receptor DCC, and that netrin-1 induces this interaction in primary neurons. TUBB3 colocalizes with DCC in the growth cones of primary neurons and MT dynamics is required for netrin-1-promoted association of TUBB3 with DCC. Netrin-1 not only increases co-sedimentation of DCC with polymerized MT, but also promotes MT dynamics in the growth cone. Knocking down TUBB3 inhibits netrin-1-induced MT dynamics, axon outgrowth and attraction in vitro and causes defects in commissural axon projection in the embryo. These results indicate that TUBB3 directly links netrin signaling pathways to MT dynamics and plays an important role in guiding commissural axons in vivo.
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Affiliation(s)
- Chao Qu
- Department of Biological Sciences, University of Toledo, M.S. 601, 2801 W. Bancroft Street, Toledo, OH 43606, USA
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289
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Son TW, Yun SP, Yong MS, Seo BN, Ryu JM, Youn HY, Oh YM, Han HJ. Netrin-1 protects hypoxia-induced mitochondrial apoptosis through HSP27 expression via DCC- and integrin α6β4-dependent Akt, GSK-3β, and HSF-1 in mesenchymal stem cells. Cell Death Dis 2013; 4:e563. [PMID: 23538444 PMCID: PMC3615739 DOI: 10.1038/cddis.2013.94] [Citation(s) in RCA: 53] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Netrin (Ntn) has the potential to be successfully applied as an anti-apoptotic agent with a high affinity for tissue, for therapeutic strategies of umbilical cord blood-derived mesenchymal stem cells (UCB-MSC), although the mechanism by which Ntn-1 protects hypoxic injury has yet to be identified. Therefore, the present study examined the effect of Ntn-1 on hypoxia-induced UCB-MSC apoptosis, as well as the potential underlying mechanisms of its protective effect. Hypoxia (72 h) reduced cell viability (MTT reduction, and [3H]-thymidine incorporation) and cell number, and induced apoptosis (annexin and/or PI positive), which were reversed by Ntn-1 (10 ng/ml). Moreover, Ntn-1 decreased the increase of hypoxia-induced Bax, cleaved caspase-9, and -3, but blocked the decrease of hypoxia-reduced Bcl-2. Next, in order to examine the Ntn-1-related signaling cascade in the protection of hypoxic injury, we analyzed six Ntn receptors in UCB-MSC. We identified deleted in colorectal cancer (DCC) and integrin (IN) α6β4, except uncoordinated family member (UNC) 5A–C, and neogenin. Among them, IN α6β4 only was detected in lipid raft fractions. In addition, Ntn-1 induced the dissociation of DCC and APPL-1 complex, thereby stimulating the formation of APPL-1 and Akt2 complex. Ntn-1 also reversed the hypoxia-induced decrease of Akt and glycogen synthase kinase 3β (GSK-3β) phosphorylation, which is involved in heat shock factor-1 (HSF-1) expression. Ntn-1-induced phospho-Akt and -GSK-3β were inhibited by DCC function-blocking antibody, IN a6b4 function-blocking antibody, and the Akt inhibitor. Hypoxia and/or Ntn-1 stimulated heat shock protein (HSP)27 expression, which was blocked by HSF-1-specific small interfering RNA (siRNA). Furthermore, HSP27-specific siRNA reversed the Ntn-1-induced increase of phospho-Akt. Additionally, HSP27-specific siRNA attenuated the Ntn-1-reduced loss of mitochondrial membrane injury via the inhibition of cytochrome c (cyt c) release and formation of cyt c and HSP27 complex. Moreover, the inhibition of each signaling protein attenuated Ntn-1-induced blockage of apoptosis. In conclusion, Ntn-1-induced HSP27 protected hypoxic injury-related UCB-MSC apoptosis through DCC- and IN α6β4-dependent Akt, GSK-3β, and HSF-1 signaling pathways.
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Affiliation(s)
- T W Son
- Department of Veterinary Internal Medicine, College of Veterinary Medicine and Research Institute for Veterinary Science, Seoul National University, Seoul, Korea
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290
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Blocking apoptotic signaling rescues axon guidance in Netrin mutants. Cell Rep 2013; 3:595-606. [PMID: 23499445 DOI: 10.1016/j.celrep.2013.02.017] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2012] [Revised: 01/14/2013] [Accepted: 02/14/2013] [Indexed: 11/21/2022] Open
Abstract
Netrins are guidance cues that form gradients to guide growing axons. We uncover a mechanism for axon guidance by demonstrating that axons can accurately navigate in the absence of a Netrin gradient if apoptotic signaling is blocked. Deletion of the two Drosophila NetA and NetB genes leads to guidance defects and increased apoptosis, and expression of either gene at the midline is sufficient to rescue the connectivity defects and cell death. Surprisingly, pan-neuronal expression of NetB rescues equally well, even though no Netrin gradient has been established. Furthermore, NetB expression blocks apoptosis, suggesting that NetB acts as a neurotrophic factor. In contrast, neuronal expression of NetA increases axon defects. Simply blocking apoptosis in NetAB mutants is sufficient to rescue connectivity, and inhibition of caspase activity in subsets of neurons rescues guidance independently of survival. In contrast to the traditional role of Netrin as simply a guidance cue, our results demonstrate that guidance and survival activities may be functionally related.
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291
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Src inhibits midline axon crossing independent of Frazzled/Deleted in Colorectal Carcinoma (DCC) receptor tyrosine phosphorylation. J Neurosci 2013; 33:305-14. [PMID: 23283343 DOI: 10.1523/jneurosci.2756-12.2013] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The phylogenetically conserved Netrin family of chemoattractants signal outgrowth and attractive turning of commissural axons through the Deleted in Colorectal Carcinoma (DCC) family of receptors. Src family kinases are thought to be major signaling effectors of Netrin/DCC. In vertebrates, Src and the closely related Fyn kinases phosphorylate DCC and form a receptor-bound signaling complex leading to activation of downstream effectors. Here we show that, in the Drosophila embryonic CNS, Src kinases are dispensable for midline attraction of commissural axons. Consistent with this observation, tyrosine phosphorylation of the Netrin receptor DCC or its Drosophila ortholog, Frazzled, is not necessary for attraction to Netrin. Moreover, we uncover an unexpected function of Src kinases: inhibition of midline axon crossing through a novel mechanism. We propose that distinct signaling outputs must exist for midline axon crossing independent of Src kinases in commissural neurons.
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292
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Roy J, Kennedy TE, Costantino S. Engineered cell culture substrates for axon guidance studies: moving beyond proof of concept. LAB ON A CHIP 2013; 13:498-508. [PMID: 23288417 DOI: 10.1039/c2lc41002h] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/01/2023]
Abstract
Promoting axon regeneration following injury is one of the ultimate challenges of neuroscience, and understanding the mechanisms that regulate axon growth and guidance is essential to achieve this goal. During development axons are directed over relatively long distances by a precise extracellular distribution of chemical signals in the embryonic nervous system. Multiple guidance proteins, including netrins, slits, semaphorins, ephrins and neurotrophins have been identified as key players in this process. During the last decade, engineered cell culture substrates have been developed to investigate the cellular and molecular mechanisms underlying axon guidance. This review is focused on the biological insights that have been achieved using new techniques that attempt to mimic in vitro the spatial patterns of proteins that growth cones encounter in vivo.
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Affiliation(s)
- Joannie Roy
- Maisonneuve-Rosemont Hospital, University of Montreal, Montreal, Canada
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293
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Horn K, Glasgow S, Gobert D, Bull SJ, Luk T, Girgis J, Tremblay ME, McEachern D, Bouchard JF, Haber M, Hamel E, Krimpenfort P, Murai K, Berns A, Doucet G, Chapman C, Ruthazer E, Kennedy T. DCC Expression by Neurons Regulates Synaptic Plasticity in the Adult Brain. Cell Rep 2013; 3:173-85. [DOI: 10.1016/j.celrep.2012.12.005] [Citation(s) in RCA: 92] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 10/01/2012] [Accepted: 12/13/2012] [Indexed: 12/01/2022] Open
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294
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Qu C, Li W, Shao Q, Dwyer T, Huang H, Yang T, Liu G. c-Jun N-terminal kinase 1 (JNK1) is required for coordination of netrin signaling in axon guidance. J Biol Chem 2012; 288:1883-95. [PMID: 23223444 DOI: 10.1074/jbc.m112.417881] [Citation(s) in RCA: 51] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
The JNK family of MAPKs is involved in a large variety of physiological and pathological processes in brain development, such as neural survival, migration, and polarity as well as axon regeneration. However, whether JNK activation is involved in axon guidance remains unknown. Here, we provide evidence indicating the JNK pathway is required for Netrin signaling in the developing nervous system. Netrin-1 increased JNK1, not JNK2 or JNK3, activity in the presence of deleted in colorectal cancer (DCC) or Down syndrome cell adhesion molecule (DSCAM), and expression of both of them further enhanced Netrin-1-induced JNK1 activity in vitro. Inhibition of JNK signaling either by a JNK inhibitor, SP600125, or expression of a dominant negative form of MKK4, a JNK upstream activator, blocked Netrin-1-induced JNK1 activation in HEK293 cells. Netrin-1 increased endogenous JNK activity in primary neurons. Netrin-1-induced JNK activation was inhibited either by the JNK inhibitor or an anti-DCC function-blocking antibody. Combination of the anti-DCC function-blocking antibody with expression of DSCAM shRNA in primary neurons totally abolished Netrin-1-induced JNK activation, whereas knockdown of DSCAM partially inhibited the Netrin-1 effect. In the developing spinal cord, phospho-JNK was strongly expressed in commissural axons before and as they crossed the floor plate, and Netrin-1 stimulation dramatically increased the level of endogenous phospho-JNK in commissural axon growth cones. Inhibition of JNK signaling either by JNK1 RNA interference (RNAi) or the JNK inhibitor suppressed Netrin-1-induced neurite outgrowth and axon attraction. Knockdown of JNK1 in ovo caused defects in spinal cord commissural axon projection and pathfinding. Our study reveals that JNK1 is important in the coordination of DCC and DSCAM in Netrin-mediated attractive signaling.
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Affiliation(s)
- Chao Qu
- Department of Biological Sciences, University of Toledo, Toledo, Ohio 43606, USA
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295
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Xu Y, Quinn CC. MIG-10 functions with ABI-1 to mediate the UNC-6 and SLT-1 axon guidance signaling pathways. PLoS Genet 2012; 8:e1003054. [PMID: 23209429 PMCID: PMC3510047 DOI: 10.1371/journal.pgen.1003054] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 09/07/2012] [Indexed: 11/30/2022] Open
Abstract
Extracellular guidance cues steer axons towards their targets by eliciting morphological changes in the growth cone. A key part of this process is the asymmetric recruitment of the cytoplasmic scaffolding protein MIG-10 (lamellipodin). MIG-10 is thought to asymmetrically promote outgrowth by inducing actin polymerization. However, the mechanism that links MIG-10 to actin polymerization is not known. We have identified the actin regulatory protein ABI-1 as a partner for MIG-10 that can mediate its outgrowth-promoting activity. The SH3 domain of ABI-1 binds to MIG-10, and loss of function of either of these proteins causes similar axon guidance defects. Like MIG-10, ABI-1 functions in both the attractive UNC-6 (netrin) pathway and the repulsive SLT-1 (slit) pathway. Dosage sensitive genetic interactions indicate that MIG-10 functions with ABI-1 and WVE-1 to mediate axon guidance. Epistasis analysis reveals that ABI-1 and WVE-1 function downstream of MIG-10 to mediate its outgrowth-promoting activity. Moreover, experiments with cultured mammalian cells suggest that the interaction between MIG-10 and ABI-1 mediates a conserved mechanism that promotes formation of lamellipodia. Together, these observations suggest that MIG-10 interacts with ABI-1 and WVE-1 to mediate the UNC-6 and SLT-1 guidance pathways. To form neural circuits, axons must navigate through the developing nervous system to reach their correct targets. Axon navigation is led by the growth cone, a structure at the tip of the growing axon that responds to extracellular guidance cues. Many of these guidance cues and their receptors have been identified. However, much less is known about the internal signaling events that give rise to the structural changes required for growth cone steering. A key component of the internal response is MIG-10, a protein that becomes asymmetrically localized in response to the extracellular cues. MIG-10 is thought to serve as a scaffold that can spatially control outgrowth-promoting proteins within the growth cone. However, we do not know the identity of the outgrowth-promoting proteins that associate with MIG-10. Here we report that MIG-10 associates physically with the actin regulatory protein ABI-1. We present genetic evidence indicating that ABI-1 functions downstream of MIG-10 to mediate its outgrowth-promoting activity. Additional genetic evidence indicates that these proteins function in both attractive and repulsive guidance signaling pathways. We also present evidence suggesting that the connection between MIG-10 and ABI-1 represents a phylogenetically conserved mechanism for the control of cellular outgrowth.
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Affiliation(s)
| | - Christopher C. Quinn
- Department of Biological Sciences, University of Wisconsin–Milwaukee, Milwaukee, Wisconsin, United States of America
- * E-mail:
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296
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Shimizu A, Nakayama H, Wang P, König C, Akino T, Sandlund J, Coma S, Italiano JE, Mammoto A, Bielenberg DR, Klagsbrun M. Netrin-1 promotes glioblastoma cell invasiveness and angiogenesis by multiple pathways including activation of RhoA, cathepsin B, and cAMP-response element-binding protein. J Biol Chem 2012. [PMID: 23195957 DOI: 10.1074/jbc.m112.397398] [Citation(s) in RCA: 67] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023] Open
Abstract
Glioblastomas are very difficult tumors to treat because they are highly invasive and disseminate within the normal brain, resulting in newly growing tumors. We have identified netrin-1 as a molecule that promotes glioblastoma invasiveness. As evidence, netrin-1 stimulates glioblastoma cell invasion directly through Matrigel-coated transwells, promotes tumor cell sprouting and enhances metastasis to lymph nodes in vivo. Furthermore, netrin-1 regulates angiogenesis as shown in specific angiogenesis assays such as enhanced capillary endothelial cells (EC) sprouting and by increased EC infiltration into Matrigel plugs in vivo, as does VEGF-A. This netrin-1 signaling pathway in glioblastoma cells includes activation of RhoA and cyclic AMP response element-binding protein (CREB). A novel finding is that netrin-1-induced glioblastoma invasiveness and angiogenesis are mediated by activated cathepsin B (CatB), a cysteine protease that translocates to the cell surface as an active enzyme and co-localizes with cell surface annexin A2 (ANXA2). The specific CatB inhibitor CA-074Me inhibits netrin-1-induced cell invasion, sprouting, and Matrigel plug angiogenesis. Silencing of CREB suppresses netrin-1-induced glioblastoma cell invasion, sprouting, and CatB expression. It is concluded that netrin-1 plays an important dual role in glioblastoma progression by promoting both glioblastoma cell invasiveness and angiogenesis in a RhoA-, CREB-, and CatB-dependent manner. Targeting netrin-1 pathways may be a promising strategy for brain cancer therapy.
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Affiliation(s)
- Akio Shimizu
- Vascular Biology Program, Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts 02115, USA
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297
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Horn KE, Kennedy TE. Putting flesh on the bones: DCC combines membrane insertion with cytoskeletal reorganization to promote chemoattraction (commentary on Cotrufo et al.). Eur J Neurosci 2012; 36:3151. [PMID: 23121097 DOI: 10.1111/ejn.12011] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Affiliation(s)
- Katherine E Horn
- Department of Neurology and Neurosurgery, Montreal Neurological Institute, McGill University, 3801 University Street, Montreal, QC, H3A 2B4, Canada
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298
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Porlan E, Perez-Villalba A, Delgado AC, Ferrón SR. Paracrine regulation of neural stem cells in the subependymal zone. Arch Biochem Biophys 2012; 534:11-9. [PMID: 23073070 DOI: 10.1016/j.abb.2012.10.001] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2012] [Revised: 09/27/2012] [Accepted: 10/05/2012] [Indexed: 12/31/2022]
Abstract
Stem cells maintain their self-renewal and multipotency capacities through a self-organizing network of transcription factors and intracellular pathways activated by extracellular signaling from the microenvironment or "niche" in which they reside in vivo. In the adult mammalian brain new neurons continue to be generated throughout life of the organisms and this lifelong process of neurogenesis is supported by a reservoir of neural stem cells in the germinal regions. The discovery of adult neurogenesis in the mammalian brain has sparked great interest in defining the conditions that guide neural stem cell (NSC) maintenance and differentiation into the great variety of neuronal and glial subtypes. Here we review current knowledge regarding the paracrine regulation provided by the components of the niche and its function, focusing on the main germinal region of the adult central nervous system (CNS), the subependymal zone (SEZ).
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Affiliation(s)
- Eva Porlan
- Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas, Spain
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299
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Timofeev K, Joly W, Hadjieconomou D, Salecker I. Localized netrins act as positional cues to control layer-specific targeting of photoreceptor axons in Drosophila. Neuron 2012; 75:80-93. [PMID: 22794263 PMCID: PMC3398394 DOI: 10.1016/j.neuron.2012.04.037] [Citation(s) in RCA: 56] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 04/25/2012] [Indexed: 02/01/2023]
Abstract
A shared feature of many neural circuits is their organization into synaptic layers. However, the mechanisms that direct neurites to distinct layers remain poorly understood. We identified a central role for Netrins and their receptor Frazzled in mediating layer-specific axon targeting in the Drosophila visual system. Frazzled is expressed and cell autonomously required in R8 photoreceptors for directing their axons to the medulla-neuropil layer M3. Netrin-B is specifically localized in this layer owing to axonal release by lamina neurons L3 and capture by target neuron-associated Frazzled. Ligand expression in L3 is sufficient to rescue R8 axon-targeting defects of Netrin mutants. R8 axons target normally despite replacement of diffusible Netrin-B by membrane-tethered ligands. Finally, Netrin localization is instructive because expression in ectopic layers can retarget R8 axons. We propose that provision of localized chemoattractants by intermediate target neurons represents a highly precise strategy to direct axons to a positionally defined layer.
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Affiliation(s)
- Katarina Timofeev
- Division of Molecular Neurobiology, MRC National Institute for Medical Research, London, UK
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300
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Chen S, Charness ME. Ethanol disrupts axon outgrowth stimulated by netrin-1, GDNF, and L1 by blocking their convergent activation of Src family kinase signaling. J Neurochem 2012; 123:602-12. [PMID: 22924694 DOI: 10.1111/j.1471-4159.2012.07954.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2012] [Revised: 08/23/2012] [Accepted: 08/23/2012] [Indexed: 01/17/2023]
Abstract
Pre-natal alcohol exposure causes fetal alcohol spectrum disorders (FASD), the most common, preventable cause of developmental disability. The developing cerebellum is particularly vulnerable to the effects of ethanol. We reported that ethanol inhibits the stimulation of axon outgrowth in cerebellar granule neurons (CGN) by NAP, an active motif of activity-dependent neuroprotective protein (ADNP), by blocking NAP activation of Fyn kinase and its downstream signaling molecule, the scaffolding protein Cas. Here, we asked whether ethanol inhibits the stimulation of axon outgrowth by diverse axon guidance molecules through a common action on the Src family kinases (SFK). We first demonstrated that netrin-1, glial cell line-derived neurotrophic factor (GDNF), and neural cell adhesion molecule L1 stimulate axon outgrowth in CGNs by activating SFK, Cas, and extracellular signal-regulated kinase 1 and 2 (ERK1/2). The specific SFK inhibitor, PP2, blocked the stimulation of axon outgrowth and the activation of the SFK-Cas-ERK1/2 signaling pathway by each of these axon-guidance molecules. In contrast, brain-derived neurotrophic factor (BDNF) stimulated axon outgrowth and activated ERK1/2 without first activating SFK or Cas. Clinically relevant concentrations of ethanol inhibited axon outgrowth and the activation of the SFK-Cas-ERK1/2 pathway by netrin-1, GDNF, and L1, but did not disrupt BDNF-induced axon outgrowth or ERK1/2 activation. These results indicate that SFK, but not ERK1/2, is a primary target for ethanol inhibition of axon outgrowth. The ability of ethanol to block the convergent activation of the SFK-Cas-ERK1/2 pathway by netrin-1, GDNF, L1, and ADNP could contribute significantly to the pathogenesis of FASD.
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Affiliation(s)
- Suzhen Chen
- VA Boston Healthcare System and Department of Neurology, Harvard Medical School, West Roxbury, MA, USA
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