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Tomas-Roig J, Havemann-Reinecke U. Gene expression signature in brain regions exposed to long-term psychosocial stress following acute challenge with cannabinoid drugs. Psychoneuroendocrinology 2019; 102:1-8. [PMID: 30476795 DOI: 10.1016/j.psyneuen.2018.11.023] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2018] [Revised: 11/15/2018] [Accepted: 11/15/2018] [Indexed: 12/13/2022]
Abstract
Repeated exposure to life stressors can overwhelm the body's capacity to restore homeostasis and result in severe negative consequences. Cannabinoid CB1 receptors are highly expressed in the Central Nervous System (CNS) and regulate both glucocorticoid signalling and neurotransmitter release. In rodents, WIN55212.2 is a full agonist at the cannabinoid receptor type-1, while Rimonabant is a potent and selective cannabinoid inverse agonist at this receptor. This study aims to investigate the effect of long-term psychosocial stress following acute challenge with cannabinoid drugs on gene expression in distinct brain regions; this is done by employing digital multiplexed gene expression analysis. We found that repeated stress increased cortical mRNA levels of dopamine receptor D2, while the expression of neuregulin-1 decreased in both the prefrontal cortex and cerebellum. Further, we found that the acute injection of the agonist WIN55212.2 reduced striatal levels of dopamine receptor D2, while the use of inverse agonist Rimonabant acted in the opposite direction. The analysis of the interaction between the drugs and repeated stress revealed that defeat mice treated with WIN55212.2 showed lower expression of a set of myelin-related genes, as did the expression of SRY-box 10 and dopamine receptors-D1 and -D2 in the prefrontal cortex when compared to vehicle. In addition, in the hippocampus of stressed mice treated with WIN55212.2, we found an elevated expression of oligodendrocyte transcription factor-1, -2 and zinc finger protein 488 when compared to vehicle. In comparison to vehicle, an increase in 2',3'-Cyclic nucleotide 3'-phosphodiesterase and oligodendrocyte transcription factor-1 occurred in the cerebellum of stressed animals treated with the agonist. Moreover, treatment with Rimonabant under the influence of stress induced an overexpression of a set of myelin-related genes in the prefrontal cortex when compared to WIN-treated animals. In conclusion, repeated stress interfered with the dopaminergic system in the prefrontal cortex. We demonstrated that the expression of dopamine receptor D2 in the striatum was mediated by the CB1 receptor. Stressed mice exposed to either WIN55212.2 or Rimonabant displayed pronounced deficits in CNS myelination. In addition, the pharmacological blockage of CB1 receptor in stressed mice deregulated the expression of dopamine receptors and might lead to dysfunctions in dopamine metabolism.
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Affiliation(s)
- J Tomas-Roig
- Dept. of Psychiatry and Psychotherapy, University of Göttingen, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany; Girona Neuroimmunology and Multiple Sclerosis Unit (UNIEMTG), Dr. Josep Trueta University Hospital and Neurodegeneration and Neuroinflammation Research Group, Girona Biomedical Research Institute (IDIBGI), Spain.
| | - U Havemann-Reinecke
- Dept. of Psychiatry and Psychotherapy, University of Göttingen, Germany; Center Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, Germany
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Hu W, Wu F, Zhang Y, Gong CX, Iqbal K, Liu F. Expression of Tau Pathology-Related Proteins in Different Brain Regions: A Molecular Basis of Tau Pathogenesis. Front Aging Neurosci 2017; 9:311. [PMID: 29021756 PMCID: PMC5623682 DOI: 10.3389/fnagi.2017.00311] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2017] [Accepted: 09/12/2017] [Indexed: 12/14/2022] Open
Abstract
Microtubule-associated protein tau is hyperphosphorylated and aggregated in affected neurons in Alzheimer disease (AD) brains. The tau pathology starts from the entorhinal cortex (EC), spreads to the hippocampus and frontal and temporal cortices, and finally to all isocortex areas, but the cerebellum is spared from tau lesions. The molecular basis of differential vulnerability of different brain regions to tau pathology is not understood. In the present study, we analyzed brain regional expressions of tau and tau pathology-related proteins. We found that tau was hyperphosphorylated at multiple sites in the frontal cortex (FC), but not in the cerebellum, from AD brain. The level of tau expression in the cerebellum was about 1/4 of that seen in the frontal and temporal cortices in human brain. In the rat brain, the expression level of tau with three microtubule-binding repeats (3R-tau) was comparable in the hippocampus, EC, FC, parietal-temporal cortex (PTC), occipital-temporal cortex (OTC), striatum, thalamus, olfactory bulb (OB) and cerebellum. However, the expression level of 4R-tau was the highest in the EC and the lowest in the cerebellum. Tau phosphatases, kinases, microtubule-related proteins and other tau pathology-related proteins were also expressed in a region-specific manner in the rat brain. These results suggest that higher levels of tau and tau kinases in the EC and low levels of these proteins in the cerebellum may accounts for the vulnerability and resistance of these representative brain regions to the development of tau pathology, respectively. The present study provides the regional expression profiles of tau and tau pathology-related proteins in the brain, which may help understand the brain regional vulnerability to tau pathology in neurodegenerative tauopathies.
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Affiliation(s)
- Wen Hu
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, United States.,Key Laboratory of Neuroregeneration of Jiangsu Province and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Feng Wu
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, United States
| | - Yanchong Zhang
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, United States.,Key Laboratory of Neuroregeneration of Jiangsu Province and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
| | - Cheng-Xin Gong
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, United States
| | - Khalid Iqbal
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, United States
| | - Fei Liu
- Department of Neurochemistry, New York State Institute for Basic Research in Developmental Disabilities, Staten Island, NY, United States.,Key Laboratory of Neuroregeneration of Jiangsu Province and Ministry of Education, Co-innovation Center of Neuroregeneration, Nantong University, Nantong, China
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Andrés-Benito P, Moreno J, Aso E, Povedano M, Ferrer I. Amyotrophic lateral sclerosis, gene deregulation in the anterior horn of the spinal cord and frontal cortex area 8: implications in frontotemporal lobar degeneration. Aging (Albany NY) 2017; 9:823-851. [PMID: 28283675 PMCID: PMC5391234 DOI: 10.18632/aging.101195] [Citation(s) in RCA: 42] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2016] [Accepted: 02/27/2017] [Indexed: 12/14/2022]
Abstract
Transcriptome arrays identifies 747 genes differentially expressed in the anterior horn of the spinal cord and 2,300 genes differentially expressed in frontal cortex area 8 in a single group of typical sALS cases without frontotemporal dementia compared with age-matched controls. Main up-regulated clusters in the anterior horn are related to inflammation and apoptosis; down-regulated clusters are linked to axoneme structures and protein synthesis. In contrast, up-regulated gene clusters in frontal cortex area 8 involve neurotransmission, synaptic proteins and vesicle trafficking, whereas main down-regulated genes cluster into oligodendrocyte function and myelin-related proteins. RT-qPCR validates the expression of 58 of 66 assessed genes from different clusters. The present results: a. reveal regional differences in de-regulated gene expression between the anterior horn of the spinal cord and frontal cortex area 8 in the same individuals suffering from sALS; b. validate and extend our knowledge about the complexity of the inflammatory response in the anterior horn of the spinal cord; and c. identify for the first time extensive gene up-regulation of neurotransmission and synaptic-related genes, together with significant down-regulation of oligodendrocyte- and myelin-related genes, as important contributors to the pathogenesis of frontal cortex alterations in the sALS/frontotemporal lobar degeneration spectrum complex at stages with no apparent cognitive impairment.
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Affiliation(s)
- Pol Andrés-Benito
- Institute of Neuropathology, Pathologic Anatomy Service, Bellvitge University Hospital, IDIBELL, Hospitalet de Llobregat, Spain
| | - Jesús Moreno
- Institute of Neuropathology, Pathologic Anatomy Service, Bellvitge University Hospital, IDIBELL, Hospitalet de Llobregat, Spain
| | - Ester Aso
- Institute of Neuropathology, Pathologic Anatomy Service, Bellvitge University Hospital, IDIBELL, Hospitalet de Llobregat, Spain
| | - Mónica Povedano
- Service of Neurology, Bellvitge University Hospital, Hospitalet de Llobregat, Spain
| | - Isidro Ferrer
- Institute of Neuropathology, Pathologic Anatomy Service, Bellvitge University Hospital, IDIBELL, Hospitalet de Llobregat, Spain
- Department of Pathology and Experimental Therapeutics, University of Barcelona, Spain
- Institute of Neurosciences, University of Barcelona, Barcelona, Spain
- Biomedical Network Research Center on Neurodegenerative Diseases (CIBERNED), Institute Carlos III, Hospitalet de Llobregat, Spain
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Molecular Biomarkers for Embryonic and Adult Neural Stem Cell and Neurogenesis. BIOMED RESEARCH INTERNATIONAL 2015; 2015:727542. [PMID: 26421301 PMCID: PMC4569757 DOI: 10.1155/2015/727542] [Citation(s) in RCA: 100] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/27/2014] [Accepted: 11/19/2014] [Indexed: 02/07/2023]
Abstract
The procedure of neurogenesis has made numerous achievements in the past decades, during which various molecular biomarkers have been emerging and have been broadly utilized for the investigation of embryonic and adult neural stem cell (NSC). Nevertheless, there is not a consistent and systematic illustration to depict the functional characteristics of the specific markers expressed in distinct cell types during the different stages of neurogenesis. Here we gathered and generalized a series of NSC biomarkers emerging during the procedures of embryonic and adult neural stem cell, which may be used to identify the subpopulation cells with distinguishing characters in different timeframes of neurogenesis. The identifications of cell patterns will provide applications to the detailed investigations of diverse developmental cell stages and the extents of cell differentiation, which will facilitate the tracing of cell time-course and fate determination of specific cell types and promote the further and literal discoveries of embryonic and adult neurogenesis. Meanwhile, via the utilization of comprehensive applications under the aiding of the systematic knowledge framework, researchers may broaden their insights into the derivation and establishment of novel technologies to analyze the more detailed process of embryogenesis and adult neurogenesis.
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Wang J, Qiao J, Zhang Y, Wang H, Zhu S, Zhang H, Hartle K, Guo H, Guo W, He J, Kong J, Huang Q, Li XM. Desvenlafaxine prevents white matter injury and improves the decreased phosphorylation of the rate-limiting enzyme of cholesterol synthesis in a chronic mouse model of depression. J Neurochem 2014; 131:229-38. [PMID: 24934403 DOI: 10.1111/jnc.12792] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/11/2014] [Revised: 06/11/2014] [Accepted: 06/12/2014] [Indexed: 01/07/2023]
Abstract
Serotonin/norepinephrine reuptake inhibitors antidepressants exert their effects by increasing serotonin and norepinephrine in the synaptic cleft. Studies show it takes 2-3 weeks for the mood-enhancing effects, which indicate other mechanisms may underlie their treatment effects. Here, we investigated the role of white matter in treatment and pathogenesis of depression using an unpredictable chronic mild stress (UCMS) mouse model. Desvenlafaxine (DVS) was orally administrated to UCMS mice at the dose of 10 mg/kg/day 1 week before they went through a 7-week stress procedure and lasted for over 8 weeks before the mice were killed. No significant changes were found for protein markers of neurons and astrocytes in UCMS mice. However, myelin and oligodendrocyte-related proteins were significantly reduced in UCMS mice. DVS prevented the stress-induced injury to white matter and the decrease of phosphorylated 5'-AMP-activated protein kinase and 3-hydroxy-3-methyl-glutaryl-CoA reductase protein expression. DVS increased open arm entries in an elevated plus-maze test, sucrose consumption in the sucrose preference test and decreased immobility in tail suspension and forced swimming tests. These findings suggest that stress induces depression-like behaviors and white matter deficits in UCMS mice. DVS may ameliorate the oligodendrocyte dysfunction by affecting cholesterol synthesis, alleviating the depression-like phenotypes in these mice. We examined the possible role of oligodendrocyte and myelin in the pathological changes of depression with an unpredictable chronic mild stress (UCMS) mouse model. Oligodendrocyte-related proteins in the mouse brain were specifically changed during the stress period. The depressive-like behaviors and oligodendrocyte deficits could be prevented by the administration of desvenlafaxine. Oligodendrocyte and myelin may be an essential target of desvenlafaxine for the treatment of depression.
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Affiliation(s)
- Junhui Wang
- Mental Health Center, Shantou University, Shantou, Guangdong, China.,Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Jinping Qiao
- Mental Health Center, Shantou University, Shantou, Guangdong, China.,Clinical Laboratory, the First Affiliated Hospital of Anhui Medical University, Hefei, Anhui, China.,Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Yanbo Zhang
- Department of Psychiatry, College of Medicine, University of Saskatchewan, Saskatoon, Saskatchewan, Canada
| | - Hongxing Wang
- Department of Clinical Psychiatry, Beijing Anding Hospital, Capital Medical University, Beijing, China
| | - Shenghua Zhu
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Handi Zhang
- Mental Health Center, Shantou University, Shantou, Guangdong, China
| | - Kelly Hartle
- Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Huining Guo
- Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Wei Guo
- Department of Clinical Psychiatry, Beijing Anding Hospital, Capital Medical University, Beijing, China
| | - Jue He
- Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
| | - Jiming Kong
- Department of Human Anatomy and Cell Science, University of Manitoba, Winnipeg, Manitoba, Canada
| | - Qingjun Huang
- Mental Health Center, Shantou University, Shantou, Guangdong, China
| | - Xin-Min Li
- Department of Psychiatry, Faculty of Medicine and Dentistry, University of Alberta, Edmonton, Alberta, Canada
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Mustapha O, Oke B, Offen N, Sirén AL, Olopade J. Neurobehavioral and cytotoxic effects of vanadium during oligodendrocyte maturation: a protective role for erythropoietin. ENVIRONMENTAL TOXICOLOGY AND PHARMACOLOGY 2014; 38:98-111. [PMID: 24927405 DOI: 10.1016/j.etap.2014.05.001] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 05/01/2014] [Accepted: 05/02/2014] [Indexed: 06/03/2023]
Abstract
Vanadium exposure has been known to lead to lipid peroxidation, demyelination and oligodendrocytes depletion. We investigated behaviour and glial reactions in juvenile mice after early neonatal exposure to vanadium, and examined the direct effects of vanadium in oligodendrocyte progenitor cultures from embryonic mice. Neonatal pups exposed to vanadium via lactation for 15 and 22 days all had lower body weights. Behavioural tests showed in most instances a reduction in locomotor activity and negative geotaxis. Brain analyses revealed astrocytic activation and demyelination in the vanadium exposed groups compared to the controls. In cell culture, exposure of oligodendrocytes to 300 μM sodium metavanadate significantly increased cell death. Expression of the oligodendrocyte specific proteins, 2',3'-cyclic nucleotide 3'-phosphodiesterase (CNPase) and oligodendrocyte specific protein (OSP/Claudin) were reduced upon vanadium treatment while simultaneous administration of erythropoietin (EPO; 4-12 U/ml) counteracted vanadium-toxicity. The data suggest that oligodendrocyte damage may explain the increased vulnerability of the juvenile brain to vanadium and support a potential for erythropoietin as a protective agent against vanadium-toxicity during perinatal brain development and maturation.
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Affiliation(s)
- Oluwaseun Mustapha
- Department of Veterinary Anatomy, University of Ibadan, Nigeria; Department of Veterinary Anatomy, Federal University of Agriculture, Abeokuta, Nigeria.
| | - Bankole Oke
- Department of Veterinary Anatomy, University of Ibadan, Nigeria.
| | - Nils Offen
- Department of Neurosurgery, University of Würzburg, Josef-Schneider Strasse 11, 97080 Würzburg, Germany.
| | - Anna-Leena Sirén
- Department of Neurosurgery, University of Würzburg, Josef-Schneider Strasse 11, 97080 Würzburg, Germany.
| | - James Olopade
- Department of Veterinary Anatomy, University of Ibadan, Nigeria; Department of Neurosurgery, University of Würzburg, Josef-Schneider Strasse 11, 97080 Würzburg, Germany.
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7
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Hong EJ, Jeung EB. Assessment of Developmental Toxicants using Human Embryonic Stem Cells. Toxicol Res 2014; 29:221-7. [PMID: 24578791 PMCID: PMC3936173 DOI: 10.5487/tr.2013.29.4.221] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2013] [Revised: 12/05/2013] [Accepted: 12/12/2013] [Indexed: 01/16/2023] Open
Abstract
Embryonic stem (ES) cells have potential for use in evaluation of developmental toxicity because they are generated in large numbers and differentiate into three germ layers following formation of embryoid bodies (EBs). In earlier study, embryonic stem cell test (EST) was established for assessment of the embryotoxic potential of compounds. Using EBs indicating the onset of differentiation of mouse ES cells, many toxicologists have refined the developmental toxicity of a variety of compounds. However, due to some limitation of the EST method resulting from species-specific differences between humans and mouse, it is an incomplete approach. In this regard, we examined the effects of several developmental toxic chemicals on formation of EBs using human ES cells. Although human ES cells are fastidious in culture and differentiation, we concluded that the relevancy of our experimental method is more accurate than that of EST using mouse ES cells. These types of studies could extend our understanding of how human ES cells could be used for monitoring developmental toxicity and its relevance in relation to its differentiation progress. In addition, this concept will be used as a model system for screening for developmental toxicity of various chemicals. This article might update new information about the usage of embryonic stem cells in the context of their possible ability in the toxicological fields.
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Affiliation(s)
- Eui-Ju Hong
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Korea
| | - Eui-Bae Jeung
- Laboratory of Veterinary Biochemistry and Molecular Biology, College of Veterinary Medicine, Chungbuk National University, Cheongju, Korea
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Guptarak J, Wiktorowicz JE, Sadygov RG, Zivadinovic D, Paulucci-Holthauzen AA, Vergara L, Nesic O. The cancer drug tamoxifen: a potential therapeutic treatment for spinal cord injury. J Neurotrauma 2013; 31:268-83. [PMID: 24004276 DOI: 10.1089/neu.2013.3108] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Tamoxifen (TMX) is a selective estrogen receptor modulator that can mimic the neuroprotective effects of estrogen but lacks its systemic adverse effects. We found that TMX (1 mg/day) significantly improved the motor recovery of partially paralyzed hind limbs of male adult rats with thoracic spinal cord injury (SCI), thus indicating a translational potential for this cancer medication given its clinical safety and applicability and the lack of currently available treatments for SCI. To shed light on the mechanisms underlying the beneficial effects of TMX for SCI, we used proteomic analyses, Western blots and histological assays, which showed that TMX treatment spared mature oligodendrocytes/increased myelin levels and altered reactive astrocytes, including the upregulation of the water channels aquaporin 4 (AQP4), a novel finding. AQP4 increases in TMX-treated SCI rats were associated with smaller fluid-filled cavities with borders consisting of densely packed AQP4-expressing astrocytes that closely resemble the organization of normal glia limitans externa (in contrast to large cavities in control SCI rats that lacked glia limitans-like borders and contained reactive glial cells). Based on our findings, we propose that TMX is a promising candidate for the therapeutic treatment of SCI and a possible intervention for other neuropathological conditions associated with demyelination and AQP4 dysfunction.
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Affiliation(s)
- Jutatip Guptarak
- 1 Department of Biochemistry and Molecular Biology, University of Texas Medical Branch , Galveston, Texas
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Schweigreiter R, Roots BI, Bandtlow CE, Gould RM. Understanding Myelination Through Studying Its Evolution. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2006; 73:219-73. [PMID: 16737906 DOI: 10.1016/s0074-7742(06)73007-0] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Affiliation(s)
- Rüdiger Schweigreiter
- Medical University Innsbruck, Biocenter Innsbruck, Division of Neurobiochemistry, A-6020 Innsbruck, Austria
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Sakamoto Y, Tanaka N, Ichimiya T, Kurihara T, Nakamura KT. Crystal structure of the catalytic fragment of human brain 2',3'-cyclic-nucleotide 3'-phosphodiesterase. J Mol Biol 2005; 346:789-800. [PMID: 15713463 DOI: 10.1016/j.jmb.2004.12.024] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2004] [Revised: 12/12/2004] [Accepted: 12/14/2004] [Indexed: 11/18/2022]
Abstract
2',3'-Cyclic-nucleotide 3'-phosphodiesterase (CNP), a member of the 2H phosphoesterase superfamily, is firmly bound to brain white matter and found mainly in the central nervous system of vertebrates, and it catalyzes the hydrolysis of 2',3'-cyclic nucleotide to produce 2'-nucleotide. Recent studies on CNP-knockout mice have revealed that the absence of CNP causes axonal swelling and neuronal degeneration. Here, the crystal structure of the catalytic fragment (CF) of human CNP (hCNP-CF) is solved at 1.8A resolution. It is an alpha+beta type structure consisting of three alpha-helices and nine beta-strands. The structural core of the molecule is comprised of two topologically equivalent three-stranded antiparallel beta-sheets that are related by a pseudo 2-fold symmetry. Each beta-sheet contains an H-X-T-X motif, which is strictly conserved among members of the 2H phosphoesterase superfamily. The phosphate ion is bound to the side-chains of His and Thr from each of the two motifs. Structural comparison of hCNP-CF with plant 1'',2''-cyclic nucleotide phosphodiesterase (CPDase) and bacterial 2'-5' RNA ligase reveals that the H-X-T-X motifs are structurally conserved among these enzymes, but the surface properties of the active site are quite different among the enzymes, reflecting the differences in their substrates. On the basis of the present crystal structure of the hCNP-CF/phosphate complex, the available structure of the CPDase/cyclic-nucleotide analogue complex, and the recent functional studies of rat CNP-CF, we propose a possible substrate-binding mode and catalytic mechanism of CNP, which employs the nucleophilic water molecule activated by His310. The proposed mechanism is basically equivalent to the second step of the well-accepted reaction mechanism of RNase A. Since the overall structure of hCNP-CF differs considerably from that of RNase A, it is likely that the similar active sites with two catalytic histidine residues in these enzymes arose through convergent evolution.
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Affiliation(s)
- Yasumitsu Sakamoto
- School of Pharmaceutical Sciences, Showa University, 1-5-8 Hatanodai, Shinagawa-ku, Tokyo 142-8555, Japan
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11
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Lee J, Gravel M, Gao E, O'Neill RC, Braun PE. Identification of essential residues in 2',3'-cyclic nucleotide 3'-phosphodiesterase. Chemical modification and site-directed mutagenesis to investigate the role of cysteine and histidine residues in enzymatic activity. J Biol Chem 2001; 276:14804-13. [PMID: 11278504 DOI: 10.1074/jbc.m009434200] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
2',3'-Cyclic nucleotide 3'-phosphodiesterase (CNP; EC ) catalyzes in vitro hydrolysis of 3'-phosphodiester bonds in 2',3'-cyclic nucleotides to produce 2'-nucleotides exclusively. N-terminal deletion mapping of the C-terminal two-thirds of recombinant rat CNP1 identified a region that possesses the catalytic domain, with further truncations abolishing activity. Proteolysis and kinetic analysis indicated that this domain forms a compact globular structure and contains all of the catalytically essential features. Subsequently, this catalytic fragment of CNP1 (CNP-CF) was used for chemical modification studies to identify amino acid residues essential for activity. 5,5'-Dithiobis-(2-nitrobenzoic acid) modification studies and kinetic analysis of cysteine CNP-CF mutants revealed the nonessential role of cysteines for enzymatic activity. On the other hand, modification studies with diethyl pyrocarbonate indicated that two histidines are essential for CNPase activity. Consequently, the only two conserved histidines, His-230 and His-309, were mutated to phenylalanine and leucine. All four histidine mutants had k(cat) values 1000-fold lower than wild-type CNP-CF, but K(m) values were similar. Circular dichroism studies demonstrated that the low catalytic activities of the histidine mutants were not due to gross changes in secondary structure. Taken together, these results demonstrate that both histidines assume critical roles for catalysis.
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Affiliation(s)
- J Lee
- Department of Biochemistry, McGill University, Montreal, Quebec H3G 1Y6, Canada
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12
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Tohyama Y, Ichimiya T, Kasama-Yoshida H, Cao Y, Hasegawa M, Kojima H, Tamai Y, Kurihara T. Phylogenetic relation of lungfish indicated by the amino acid sequence of myelin DM20. BRAIN RESEARCH. MOLECULAR BRAIN RESEARCH 2000; 80:256-9. [PMID: 11038260 DOI: 10.1016/s0169-328x(00)00143-1] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The cDNA of lungfish Protopterus annectens myelin DM20 was cloned, and the complete amino acid sequence of Protopterusannectens DM20 was deduced. When five possible phylogenetic trees were tested for the DM20 sequences, the maximum likelihood method supported tree 1 [((tetrapods, lungfish), coelacanth), zebrafish, shark] or tree 5 [(tetrapods, lungfish), (coelacanth, zebrafish), shark]. Both tree 1 and tree 5 indicate that lungfish is phylogenetically the closest to tetrapods among the living fishes.
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Affiliation(s)
- Y Tohyama
- Institute of Life Science, Soka University, Hachioji, 192-8577, Tokyo, Japan
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13
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Ballestero RP, Dybowski JA, Levy G, Agranoff BW, Uhler MD. Cloning and characterization of zRICH, a 2',3'-cyclic-nucleotide 3'-phosphodiesterase induced during zebrafish optic nerve regeneration. J Neurochem 1999; 72:1362-71. [PMID: 10098837 DOI: 10.1046/j.1471-4159.1999.721362.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
We previously reported cloning of cDNAs encoding both components of a protein doublet induced during goldfish optic nerve regeneration. The predicted protein sequences showed significant homology with the mammalian 2',3'-cyclic-nucleotide 3'-phosphodiesterases (CNPases). CNPases are well-established markers of mammalian myelin; hence, the cDNAs were designated gRICH68 and gRICH70 (for goldfish Regeneration-Induced CNPase Homologues of 68 and 70 kDa). Homologous cDNAs have now been isolated from zebrafish encoding a highly related protein, which we have termed zRICH. RNase protection assays show that zRICH mRNA is induced significantly (fivefold) in optic nerve regenerating zebrafish retinas 7 days following nerve crush. Western blots show a single band in zebrafish brain and retina extracts, with immunoreactivity increasing three-fold in regenerating retinas 21 days postcrush. Immunohistochemical analysis indicated that this increase in zRICH protein expression is localized to the retinal ganglion cell layer in regenerating retina. We have characterized and evaluated the relevance of a conserved beta-ketoacyl synthase motif in zRICH to CNPase activity by means of site-directed mutagenesis. Two residues within the motif, H334 and T336, are critical for enzymatic activity. A cysteine residue within the motif, which corresponds to a critical residue for beta-ketoacyl synthase, does not appear to participate in the phosphodiesterase activity.
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Affiliation(s)
- R P Ballestero
- Department of Biological Chemistry and Mental Health Research Institute, University of Michigan, Ann Arbor 48104-1687, USA
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