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Heng J, Lv P, Zhang Y, Cheng X, Wang L, Ma D, Liu F. Rab5c-mediated endocytic trafficking regulates hematopoietic stem and progenitor cell development via Notch and AKT signaling. PLoS Biol 2020; 18:e3000696. [PMID: 32275659 PMCID: PMC7176290 DOI: 10.1371/journal.pbio.3000696] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2019] [Revised: 04/22/2020] [Accepted: 03/24/2020] [Indexed: 12/12/2022] Open
Abstract
It is well known that various developmental signals play diverse roles in hematopoietic stem and progenitor cell (HSPC) production; however, how these signaling pathways are orchestrated remains incompletely understood. Here, we report that Rab5c is essential for HSPC specification by endocytic trafficking of Notch and AKT signaling in zebrafish embryos. Rab5c deficiency leads to defects in HSPC production. Mechanistically, Rab5c regulates hemogenic endothelium (HE) specification by endocytic trafficking of Notch ligands and receptor. We further show that the interaction between Rab5c and Appl1 in the endosome is required for the survival of HE in the ventral wall of the dorsal aorta through AKT signaling. Interestingly, Rab5c overactivation can also lead to defects in HSPC production, which is attributed to excessive endolysosomal trafficking inducing Notch signaling defect. Taken together, our findings establish a previously unrecognized role of Rab5c-mediated endocytic trafficking in HSPC development and provide new insights into how spatiotemporal signals are orchestrated to accurately execute cell fate transition. Cell-autonomous Notch signaling regulated by the membrane trafficking protein Rab5c plays an instructive role in hematopoietic stem and progenitor cell specification, while the AKT signaling seems to provide a permissive signal to maintain hemogenic endothelium survival.
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Affiliation(s)
- Jian Heng
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Peng Lv
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Yifan Zhang
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Xinjie Cheng
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
| | - Lu Wang
- State Key Laboratory of Experimental Hematology, Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China
| | - Dongyuan Ma
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
| | - Feng Liu
- State Key Laboratory of Membrane Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing, China
- Institute for Stem Cell and Regeneration, Chinese Academy of Sciences, Beijing, China
- * E-mail:
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2
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Banworth MJ, Li G. Consequences of Rab GTPase dysfunction in genetic or acquired human diseases. Small GTPases 2018. [PMID: 29239692 DOI: 10.1080/215412481397833] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/23/2023] Open
Abstract
Rab GTPases are important regulators of intracellular membrane trafficking in eukaryotes. Both activating and inactivating mutations in Rab genes have been identified and implicated in human diseases ranging from neurological disorders to cancer. In addition, altered Rab expression is often associated with disease prognosis. As such, the study of diseases associated with Rabs or Rab-interacting proteins has shed light on the important role of intracellular membrane trafficking in disease etiology. In this review, we cover recent advances in the field with an emphasis on cellular mechanisms.
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Affiliation(s)
- Marcellus J Banworth
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
| | - Guangpu Li
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
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3
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Banworth MJ, Li G. Consequences of Rab GTPase dysfunction in genetic or acquired human diseases. Small GTPases 2017; 9:158-181. [PMID: 29239692 DOI: 10.1080/21541248.2017.1397833] [Citation(s) in RCA: 39] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Rab GTPases are important regulators of intracellular membrane trafficking in eukaryotes. Both activating and inactivating mutations in Rab genes have been identified and implicated in human diseases ranging from neurological disorders to cancer. In addition, altered Rab expression is often associated with disease prognosis. As such, the study of diseases associated with Rabs or Rab-interacting proteins has shed light on the important role of intracellular membrane trafficking in disease etiology. In this review, we cover recent advances in the field with an emphasis on cellular mechanisms.
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Affiliation(s)
- Marcellus J Banworth
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
| | - Guangpu Li
- a Department of Biochemistry and Molecular Biology , University of Oklahoma Health Sciences Center , Oklahoma City , OK , USA
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4
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Cao F, Chen M, Li G, Ye K, Huang X, Zheng X. Altered expression of metabotropic glutamate receptor 1 alpha after acute diffuse brain injury: Effect of the competitive antagonist 1-aminoindan-1, 5-dicarboxylic acid. Neural Regen Res 2015; 7:119-24. [PMID: 25767486 PMCID: PMC4354126 DOI: 10.3969/j.issn.1673-5374.2012.02.007] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2011] [Accepted: 11/22/2011] [Indexed: 02/06/2023] Open
Abstract
The diffuse brain injury model was conducted in Sprague-Dawley rats, according to Marmarou's free-fall attack. The water content in brain tissue, expression of metabotropic glutamate receptor 1α mRNA and protein were significantly increased after injury, reached a peak at 24 hours, and then gradually decreased. After treatment with the competitive antagonist of metabotropic glutamate receptor 1α, (RS)-1-aminoindan-1, 5-dicarboxylic acid, the water content of brain tissues decreased between 12–72 hours after injury, and neurological behaviors improved at 2 weeks. These experimental findings suggest that the 1-aminoindan-1, 5-dicarboxylic acid may result in marked neuroprotection against diffuse brain injury.
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Affiliation(s)
- Fei Cao
- Department of Neurosurgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China ; Institute of Brain Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China
| | - Mantao Chen
- Department of Neurosurgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China ; Institute of Brain Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China
| | - Gu Li
- Department of Neurosurgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China ; Institute of Brain Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China
| | - Ke Ye
- Department of Neurosurgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China ; Institute of Brain Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China
| | - Xin Huang
- Department of Neurosurgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China ; Institute of Brain Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China
| | - Xiujue Zheng
- Department of Neurosurgery, First Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China ; Institute of Brain Medicine, Zhejiang University, Hangzhou 310003, Zhejiang Province, China
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5
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Huang Y, Ren Q. Identification and function of 11 Rab GTPases in giant freshwater prawn Macrobrachium rosenbergii. FISH & SHELLFISH IMMUNOLOGY 2015; 43:120-130. [PMID: 25542378 DOI: 10.1016/j.fsi.2014.12.021] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/24/2014] [Revised: 12/15/2014] [Accepted: 12/16/2014] [Indexed: 06/04/2023]
Abstract
Rab GTPases, members of the Ras-like GTPase superfamily, are central elements in endocytic membrane trafficking. However, little is known of the Rab genes in the giant freshwater prawn Macrobrachium rosenbergii. In this study, 11 Rab genes were identified from M. rosenbergii. All MrRabs have a RAB domain. Phylogenetic analysis showed that these 11 MrRabs were divided into different groups. The MrRab genes were ubiquitously expressed in heart, hemocytes, hepatopancreas, gills, stomach, and intestines. Real-time polymerase chain reaction revealed that the MrRab genes were significantly upregulated by white spot syndrome virus (WSSV) in the prawns, indicating that MrRabs might play an important role in innate immune response against WSSV. Moreover, after challenge with Vibrio parahaemolyticus, the expression levels of all MrRabs in the hepatopancreas were also upregulated, which might indicated the involvement of MrRabs in prawns antibacterial immunity. In all, these preliminary results showed that MrRabs were involved in innate immunity of M. rosenbergii.
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Affiliation(s)
- Ying Huang
- Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046, PR China
| | - Qian Ren
- Jiangsu Key Laboratory for Biodiversity & Biotechnology and Jiangsu Key Laboratory for Aquatic Crustacean Diseases, College of Life Sciences, Nanjing Normal University, 1 Wenyuan Road, Nanjing 210046, PR China.
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6
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Kenyon EJ, Campos I, Bull JC, Williams PH, Stemple DL, Clark MD. Zebrafish Rab5 proteins and a role for Rab5ab in nodal signalling. Dev Biol 2014; 397:212-24. [PMID: 25478908 PMCID: PMC4294769 DOI: 10.1016/j.ydbio.2014.11.007] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Revised: 11/03/2014] [Accepted: 11/11/2014] [Indexed: 01/08/2023]
Abstract
The RAB5 gene family is the best characterised of all human RAB families and is essential for in vitro homotypic fusion of early endosomes. In recent years, the disruption or activation of Rab5 family proteins has been used as a tool to understand growth factor signal transduction in whole animal systems such as Drosophila melanogaster and zebrafish. In this study we have examined the functions for four rab5 genes in zebrafish. Disruption of rab5ab expression by antisense morpholino oligonucleotide (MO) knockdown abolishes nodal signalling in early zebrafish embryos, whereas overexpression of rab5ab mRNA leads to ectopic expression of markers that are normally downstream of nodal signalling. By contrast MO disruption of other zebrafish rab5 genes shows little or no effect on expression of markers of dorsal organiser development. We conclude that rab5ab is essential for nodal signalling and organizer specification in the developing zebrafish embryo. We have examined the activities of each of the zebrafish Rab5 genes using morpholino knockdowns. Loss of one Rab5 isoform, Rab5ab, affects formation of the dorsal organizer. Rab5ab overexpression leads to ectopic expression of dorsal markers.
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Affiliation(s)
- Emma J Kenyon
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Isabel Campos
- Champalimaud Centre for the Unknown, Fundação Champalimaud, Lisboa, Portugal
| | - James C Bull
- Department of Biosciences, Swansea University, Swansea SA2 8PP, United Kingdom
| | - P Huw Williams
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom
| | - Derek L Stemple
- Wellcome Trust Sanger Institute, Wellcome Trust Genome Campus, Hinxton, Cambridge CB10 1SA, United Kingdom.
| | - Matthew D Clark
- Sequencing Technology Development, The Genome Analysis Centre, Norwich Research Park, Colney, Norwich NR4 7UH, United Kingdom
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7
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Wang R, Zhang Y, Liu S, Li C, Sun L, Bao L, Feng J, Liu Z. Analysis of 52 Rab GTPases from channel catfish and their involvement in immune responses after bacterial infections. DEVELOPMENTAL AND COMPARATIVE IMMUNOLOGY 2014; 45:21-34. [PMID: 24513270 DOI: 10.1016/j.dci.2014.01.026] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/24/2013] [Revised: 01/31/2014] [Accepted: 01/31/2014] [Indexed: 06/03/2023]
Abstract
Rab genes, encoding a large family of monomeric G-proteins, contain over 60 members in the human genome. They have been recognized as crucial regulators for membrane trafficking including cargo sorting, vesicle formation, budding, motility, docking, fusion, secretory and endocytic pathway of host immune responses. However, little is known of the Rab gene family in teleost fish species. The development of full-length transcripts and whole genome sequences allow the identification and annotation of Rab GTPase gene family in catfish. In this study, a total of 52 Rab genes were identified from catfish cDNA and genome databases. Phylogenetic analysis assigned them into eleven subfamilies. Most Rab GTPases are conserved among vertebrates, though some of which are absent in fish genomes. Analysis of multiple RNA-seq datasets, along with real time PCR analysis revealed up-regulation of 10 Rab genes after bacterial infection. These included Rab3a, Rab4a, Rab4b, Rab5a, Rab5c, Rab7a, Rab9a, Rab11a, Rab11b, and Rab33a. Their up-regulation are temporally and spatially regulated in various tissues, but mostly induced at early stages after infection and in the gill and liver tissues, with the exception of Rab5c that is mostly up-regulated in the head kidney and trunk kidney. The complex pattern of their induced expression suggested both specific and cooperative actions of a these Rab genes in the acute immune responses to bacterial infection.
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Affiliation(s)
- Ruijia Wang
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Yu Zhang
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Shikai Liu
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Chao Li
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Luyang Sun
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Lisui Bao
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Jianbin Feng
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA
| | - Zhanjiang Liu
- The Fish Molecular Genetics and Biotechnology Laboratory, Aquatic Genomics Unit, School of Fisheries, Aquaculture and Aquatic Sciences, and Program of Cell and Molecular Biosciences, Auburn University, 203 Swingle Hall, Auburn, AL 36849, USA.
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8
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Gerace E, Scartabelli T, Formentini L, Landucci E, Moroni F, Chiarugi A, Pellegrini-Giampietro DE. Mild activation of poly(ADP-ribose) polymerase (PARP) is neuroprotective in rat hippocampal slice models of ischemic tolerance. Eur J Neurosci 2012; 36:1993-2005. [DOI: 10.1111/j.1460-9568.2012.08116.x] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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9
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Cheng F, Li X, Li Y, Wang C, Wang T, Liu G, Baskys A, Uéda K, Chan P, Yu S. α-Synuclein promotes clathrin-mediated NMDA receptor endocytosis and attenuates NMDA-induced dopaminergic cell death. J Neurochem 2011; 119:815-25. [DOI: 10.1111/j.1471-4159.2011.07460.x] [Citation(s) in RCA: 55] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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10
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Chen PI, Kong C, Su X, Stahl PD. Rab5 isoforms differentially regulate the trafficking and degradation of epidermal growth factor receptors. J Biol Chem 2009; 284:30328-38. [PMID: 19723633 DOI: 10.1074/jbc.m109.034546] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Ligand-mediated endocytosis is an intricate regulatory mechanism for epidermal growth factor receptor (EGFR) signal transduction. Coordinated trafficking of EGFR ensures its temporal and spatial communication with downstream signaling effectors. We focused our work on Rab5, a monomeric GTPase shown to participate in early stages of the endocytic pathway. Rab5 has three isoforms (A, B, and C) sharing more than 90% of sequence identity. We individually ablated endogenous isoforms in HeLa cells with short interfering RNAs and examined the loss-of-function phenotypes. We found that suppression of Rab5A or 5B hampered the degradation of EGFR, whereas Rab5C depletion had very little effect. The differential delay of EGFR degradation also corresponds with retarded progression of EGFR from early to late endosomes. We investigated the activators/effectors of Rab5A that can potentially separate its potency in EGFR degradation from other isoforms and found that Rin1, a Rab5 exchange factor, preferably associated with Rab5A. Moreover, Rab5A activation is sensitive to EGF stimulation, and suppression of Rin1 diminished this sensitivity. Based on our results together with previous work showing that Rin1 interacts with signal transducing adapter molecule to facilitate the degradation of EGFR (Kong, C., Su, X., Chen, P. I., and Stahl, P. D. (2007) J. Biol. Chem. 282, 15294-15301), we hypothesize that the selective association of Rab5A and Rin1 contributes to the dominance of Rab5A in EGFR trafficking, whereas the other isoforms may have major functions unrelated to the EGFR degradation pathway.
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Affiliation(s)
- Pin-I Chen
- Department of Cell Biology and Physiology, Washington University School of Medicine, St Louis, Missouri 63110, USA
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11
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BASKYS ANDRIUS, FANG LIWEI, BAYAZITOV ILDAR. Activation of Neuroprotective Pathways by Metabotropic Group I Glutamate Receptors: A Potential Target for Drug Discovery? Ann N Y Acad Sci 2008. [DOI: 10.1111/j.1749-6632.2005.tb00011.x] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
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12
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Baskys A, Bayazitov I, Zhu E, Fang L, Wang R. Rab-mediated endocytosis: linking neurodegeneration, neuroprotection, and synaptic plasticity? Ann N Y Acad Sci 2008; 1122:313-29. [PMID: 18077583 DOI: 10.1196/annals.1403.023] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Rab proteins are small GTPases involved in endocytosis and recycling of cell surface molecules. Recently they have been implicated in the etiopathogenesis of several neurodegenerative disorders including Alzheimer's and Lewy body disease. In experiments on organotypic hippocampal cultures, upregulation of Rab protein family member Rab5b after group I metabotropic glutamate receptor (mGluR) stimulation was associated with reduced neuronal vulnerability to excitotoxic injury. This mGluR-mediated neuroprotection was abolished by antisense-induced deficiency of Rab5b. Electrophysiological measurements of excitatory synaptic transmission in the Schaffer collateral-CA1 pathway revealed that mGluR activation that induces neuroprotection also induced long-term depression (LTD) of synaptic transmission. Similar to the neuroprotection, Rab5b deficiency abolished dihydroxyphenylglycine-induced LTD. Together, these findings support the idea that Rab proteins, and the Rab5b protein in particular, may provide a link between neurodegenerative disease, neuroprotection, and synaptic plasticity, as well as possibly being a useful target for pharmacological interventions.
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Affiliation(s)
- Andrius Baskys
- Memory Disorders Program, VA HCS Long Beach, 5901 E. 7th St. 06/116 A, Long Beach, CA 90822, USA.
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13
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Schwartz SL, Cao C, Pylypenko O, Rak A, Wandinger-Ness A. Rab GTPases at a glance. J Cell Sci 2008; 120:3905-10. [PMID: 17989088 DOI: 10.1242/jcs.015909] [Citation(s) in RCA: 329] [Impact Index Per Article: 20.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Affiliation(s)
- Samantha L Schwartz
- Department of Pathology MSC08-4640, University of New Mexico, 2325 Camino de Salud NE, CRF225, Albuquerque, NM 87131, USA
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14
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Maciejak P, Lehner M, Turzyńska D, Szyndler J, Bidziński A, Taracha E, Sobolewska A, Walkowiak J, Skórzewska A, Wisłowska A, Hamed A, Płaźnik A. The opposite role of hippocampal mGluR1 in fear conditioning in kindled and non-kindled rats. Brain Res 2008; 1187:184-93. [DOI: 10.1016/j.brainres.2007.10.010] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2007] [Revised: 10/10/2007] [Accepted: 10/11/2007] [Indexed: 11/24/2022]
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15
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Werner CG, Scartabelli T, Pancani T, Landucci E, Moroni F, Pellegrini-Giampietro DE. Differential role of mGlu1 and mGlu5 receptors in rat hippocampal slice models of ischemic tolerance. Eur J Neurosci 2007; 25:3597-604. [PMID: 17610579 DOI: 10.1111/j.1460-9568.2007.05614.x] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Activation of glutamate receptors has been proposed as a key factor in the induction of ischemic tolerance. We used organotypic rat hippocampal slices exposed to 30 min oxygen-glucose deprivation (OGD) to evaluate postischemic pyramidal cell death in the CA1 subregion. In this model, 10 min exposure to OGD 24 h before the exposure to toxic OGD was not lethal and reduced the subsequent OGD neurotoxicity by approximately 53% (ischemic preconditioning). Similarly, a 30 min exposure to the group I mGlu receptor agonist DHPG (10 microM) significantly reduced OGD neurotoxicity 24 h later (pharmacological preconditioning). Ischemic tolerance did not develop when either the selective mGlu1 antagonists LY367385 and 3-MATIDA or the AMPA/KA antagonist CNQX were present in the incubation medium during exposure to sublethal OGD. Neither the NMDA antagonist MK801 nor the mGlu5 antagonist MPEP affected the preconditioning process. On the other hand, pharmacological preconditioning was prevented not only by LY367385 or CNQX, but also by MPEP. In preconditioned slices, the toxic responses to AMPA or NMDA were reduced. The neurotoxicty of 100 microM DHPG in slices simultaneously exposed to a mild (20 min) OGD was differentially altered in the two preconditioning paradigms. After ischemic preconditioning, DHPG neurotoxicity was reduced in a manner that was sensitive to LY367385 but not to MPEP, whereas after pharmacological preconditioning it was enhanced in a manner that was sensitive to MPEP but not to LY367385. Our results show that mGlu1 and mGlu5 receptors are differentially involved in the induction and expression of ischemic tolerance following two diverse preconditioning stimuli.
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Affiliation(s)
- Claudia G Werner
- Dipartimento di Farmacologia Preclinica e Clinica, Universitá di Firenze, Viale G. Pieraccini 6, 50139 Firenze, Italy
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16
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Baskys A, Bayazitov I, Fang L, Blaabjerg M, Poulsen FR, Zimmer J. Group I metabotropic glutamate receptors reduce excitotoxic injury and may facilitate neurogenesis. Neuropharmacology 2005; 49 Suppl 1:146-56. [PMID: 16023152 DOI: 10.1016/j.neuropharm.2005.04.029] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2005] [Revised: 04/20/2005] [Accepted: 04/22/2005] [Indexed: 10/25/2022]
Abstract
Group I metabotropic glutamate receptor (mGluR) agonist DHPG reduced nerve cell death caused by their exposure to NMDA ("neuroprotective effect") and attenuated NMDA receptor-mediated currents [Blaabjerg, M., Baskys, A., Zimmer, J., Vawter, M. P., 2003b. Changes in hippocampal gene expression after neuroprotective activation of group I metabotropic glutamate receptors. Brain Research, Molecular Brain Research 117, 196-205.]. In the present study, we used organotypic hippocampal culture preparation to examine specific phospholipase C (PLC) inhibitor U73122 effects on DHPG-induced neuroprotection, changes in excitatory synaptic transmission associated with the neuroprotective DHPG treatment and a role of group I mGluR ligands in neurogenesis. Results show that short (10 min) DHPG treatment did not result in neuroprotection but significantly depressed field synaptic potentials (fEPSP) in the Schaffer collateral-CA1 pathway. The fEPSP depression was not affected by the PLC inhibitor U73122. In contrast, prolonged (2-h) treatment of cultures with DHPG induced a significant protective effect that was blocked by a PLC inhibitor U73122 but not by its inactive analog U73343. Voltage-clamp measurements of spontaneous miniature excitatory post-synaptic currents (EPSCs) recorded in CA1 neurons from cultures treated with DHPG (10 microM, 2 h) showed a significant reduction of the EPSC amplitude in DHPG-treated but not control (untreated) cultures. This reduction was completely abolished by U73122, suggesting a PLC involvement. Since activation of PLC is thought to be associated with cell proliferation, we investigated whether group I mGluR agonist DHPG or subtype antagonists LY367385 and MPEP have an effect on dentate granule cells expressing immature neuronal marker TOAD-64. DHPG (100 microM, 72 h) slightly but not significantly increased the number of TOAD-64 positive cells. The mGluR1 antagonists LY367385 (10 microM, 72 h) markedly decreased the number of TOAD-64 positive cells and mGluR5 antagonist MPEP (1 microM, 72 h) had no effect. These data suggest that (1) prolonged activation of group I mGluRs reduces nerve cell susceptibility to excitotoxic injury in a PLC-dependent manner; (2) this reduction is associated with a PLC-dependent depression of excitatory synaptic transmission; and (3) mGluR1 activation may facilitate neurogenesis.
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Affiliation(s)
- Andrius Baskys
- Department of Mental Health, VA Health Care System, Mental Illness Research and Education Clinical Center, Long Beach, University of California at Irvine, 06/116A, 5901 East Seventh Street Long Beach, CA, 90822 Irvine, CA, USA.
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17
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Carney DS, Davies BA, Horazdovsky BF. Vps9 domain-containing proteins: activators of Rab5 GTPases from yeast to neurons. Trends Cell Biol 2005; 16:27-35. [PMID: 16330212 DOI: 10.1016/j.tcb.2005.11.001] [Citation(s) in RCA: 120] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2005] [Revised: 09/26/2005] [Accepted: 11/16/2005] [Indexed: 12/11/2022]
Abstract
Endocytosis of cell surface receptors plays an important role in regulating cell signaling cascades. In some cases, internalization of an activated receptor attenuates the signaling process, while in other cases the clustering of activated receptors on early endosomal structures has been proposed to be essential for fully activating signaling cascades. Regulating the movement of receptors and other signaling proteins through the endocytic pathway, therefore, has a direct impact on cellular homeostasis. The small GTPase Rab5 is a crucial regulatory component of the endocytic pathway. Activation of Rab5 is mediated by GDP-GTP exchange factors (GEFs) that generate the Rab5-GTP complex. A large number of proteins have been identified that contain a specific, highly conserved domain (Vps9) that catalyzes nucleotide exchange on Rab5, linking the regulation of cell signaling cascades with intracellular receptor trafficking through the endocytic pathway.
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Affiliation(s)
- Darren S Carney
- Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Mayo Foundation, Rochester, MN 55905, USA
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