1
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Ling YH, Chen Y, Leung KN, Chan KM, Liu WK. Cell cycle regulation of the psoriasis associated gene CCHCR1 by transcription factor E2F1. PLoS One 2023; 18:e0294661. [PMID: 38128007 PMCID: PMC10734992 DOI: 10.1371/journal.pone.0294661] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Accepted: 11/06/2023] [Indexed: 12/23/2023] Open
Abstract
The coiled-coil alpha-helical rod protein 1 (CCHCR1) was first identified as a candidate gene in psoriasis and has lately been found to be associated with a wide range of clinical conditions including COVID-19. CCHCR1 is located within P-bodies and centrosomes, but its exact role in these two subcellular structures and its transcriptional control remain largely unknown. Here, we showed that CCHCR1 shares a bidirectional promoter with its neighboring gene, TCF19. This bidirectional promoter is activated by the G1/S-regulatory transcription factor E2F1, and both genes are co-induced during the G1/S transition of the cell cycle. A luciferase reporter assay suggests that the short intergenic sequence, only 287 bp in length, is sufficient for the G1/S induction of both genes, but the expression of CCHCR1 is further enhanced by the presence of exon 1 from both TCF19 and CCHCR1. This research uncovers the transcriptional regulation of the CCHCR1 gene, offering new perspectives on its function. These findings contribute to the broader understanding of diseases associated with CCHCR1 and may serve as a foundational benchmark for future research in these vital medical fields.
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Affiliation(s)
- Yick Hin Ling
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Yingying Chen
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - Kwok Nam Leung
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - King Ming Chan
- School of Life Sciences, Faculty of Science, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
| | - W. K. Liu
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong
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2
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Omais S, El Atie YE, Ghanem N. Rb deficiency, neuronal survival and neurodegeneration: In search of the perfect mouse model. CURRENT RESEARCH IN NEUROBIOLOGY 2023; 4:100074. [PMID: 36699152 PMCID: PMC9869410 DOI: 10.1016/j.crneur.2023.100074] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Revised: 10/26/2022] [Accepted: 01/06/2023] [Indexed: 01/14/2023] Open
Abstract
Three decades following the introduction of the first Rb knockout (KO) mouse model, the role of this critical protein in regulating brain development during embryogenesis and beyond remains a major scientific interest. Rb is a tumor suppressor gene known as the master regulator of the G1/S checkpoint and control of cell cycle progression in stem and progenitor cells, but also their differentiated progeny. Here, we review the recent literature about the various Rb conditional Knockout (cKO) and inducible Knockout (iKO) models studied thus far, highlighting how findings should always be interpreted in light of the model and context under inquiry especially when studying the role of Rb in neuronal survival. There is indeed evidence of age-specific, cell type-specific and region-specific effects following Rb KO in the embryonic and the adult mouse brain. In terms of modeling neurodegenerative processes in human diseases, we discuss cell cycle re-entry (CCE) as a candidate mechanism underlying the increased vulnerability of Rb-deficient neurons to cell death. Notably, mouse models may limit the extent to which CCE due to Rb inactivation can mimic the pathological course of these disorders, such as Alzheimer's disease. These remarks ought to be considered in future research when studying the consequences of Rb inactivation on neuronal generation and survival in rodents and their corresponding clinical significance in humans.
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Affiliation(s)
| | | | - Noël Ghanem
- Corresponding author. Department of Biology, American University of Beirut, PO Box 11-0236, Riad El Solh, 1107 2020, Beirut, Lebanon.
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3
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Omais S, Hilal RN, Halaby NN, Jaafar C, Ghanem N. Aging entails distinct requirements for Rb at maintaining adult neurogenesis. AGING BRAIN 2022; 2:100041. [PMID: 36908894 PMCID: PMC9997174 DOI: 10.1016/j.nbas.2022.100041] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/03/2022] [Revised: 04/13/2022] [Accepted: 04/28/2022] [Indexed: 10/18/2022] Open
Abstract
Cell cycle proteins play essential roles in regulating embryonic and adult neurogenesis in the mammalian brain. A key example is the Retinoblastoma protein (Rb) whose loss disrupts the whole neurogenic program during brain development, but only results in increased progenitor proliferation in the adult subventricular zone (SVZ) and compromised long-term neuronal survival in the adult olfactory bulb (OB). Whether this holds true of neurogenesis in the aged brain remains unknown. In this study, we find no evidence of irregular proliferation or early commitment defects in the mid-aged (12-month-old) and old-aged (20-month-old) SVZ following tamoxifen-inducible Rb knockout (Rb iKO) in mice. However, we highlight a striking defect in early maturation of Rb-deficient migrating neuroblasts along the rostral migratory stream (RMS), followed by massive decline in neuronal generation inside the aged OB. In the absence of Rb, we also show evidence of incomplete cell cycle re-entry (CCE) along with DNA damage in the young OB, while we find a similar trend towards CCE but no clear signs of DNA damage or neurodegenerative signatures (pTau or Synuclein accumulation) in the aged OB. However, such phenotype could be masked by the severe maturation defect reported above in addition to the natural decline in adult neurogenesis with age. Overall, we show that Rb is required to prevent CCE and DNA damage in adult-born OB neurons, hence maintain neuronal survival. Moreover, while loss of Rb alone is insufficient to trigger seeding of neurotoxic species, this study reveals age-dependent non-monotonic dynamics in regulating neurogenesis by Rb.
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Affiliation(s)
- Saad Omais
- Department of Biology, American University of Beirut, Lebanon
| | - Rouba N Hilal
- Department of Biology, American University of Beirut, Lebanon
| | - Nour N Halaby
- Department of Biology, American University of Beirut, Lebanon
| | - Carine Jaafar
- Department of Biology, American University of Beirut, Lebanon
| | - Noël Ghanem
- Department of Biology, American University of Beirut, Lebanon
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4
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Bartlett T. Fusion of single-cell transcriptome and DNA-binding data, for genomic network inference in cortical development. BMC Bioinformatics 2021; 22:301. [PMID: 34088262 PMCID: PMC8176738 DOI: 10.1186/s12859-021-04201-9] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2020] [Accepted: 05/12/2021] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Network models are well-established as very useful computational-statistical tools in cell biology. However, a genomic network model based only on gene expression data can, by definition, only infer gene co-expression networks. Hence, in order to infer gene regulatory patterns, it is necessary to also include data related to binding of regulatory factors to DNA. RESULTS We propose a new dynamic genomic network model, for inferring patterns of genomic regulatory influence in dynamic processes such as development. Our model fuses experiment-specific gene expression data with publicly available DNA-binding data. The method we propose is computationally efficient, and can be applied to genome-wide data with tens of thousands of transcripts. Thus, our method is well suited for use as an exploratory tool for genome-wide data. We apply our method to data from human fetal cortical development, and our findings confirm genomic regulatory patterns which are recognised as being fundamental to neuronal development. CONCLUSIONS Our method provides a mathematical/computational toolbox which, when coupled with targeted experiments, will reveal and confirm important new functional genomic regulatory processes in mammalian development.
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Affiliation(s)
- Thomas Bartlett
- University College London, Gower Street, London, WC1E 6BT, UK.
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5
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Brunet T, Radivojkov-Blagojevic M, Lichtner P, Kraus V, Meitinger T, Wagner M. Biallelic loss-of-function variants in RBL2 in siblings with a neurodevelopmental disorder. Ann Clin Transl Neurol 2020; 7:390-396. [PMID: 32105419 PMCID: PMC7086002 DOI: 10.1002/acn3.50992] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Revised: 01/17/2020] [Accepted: 01/19/2020] [Indexed: 12/15/2022] Open
Abstract
The RBL2 locus has been associated with intelligence and educational attainment but not with a monogenic disorder to date. RBL2 encodes p130, a member of the retinoblastoma protein family, which is involved in mediating neuron survival and death. Previous studies on p130 knockout mice revealing embryonic death and impaired neurogenesis underscore the importance of RBL2 in brain development. Exome sequencing in two siblings with severe intellectual disability, stereotypies and dysmorphic features identified biallelic loss-of-function variants c.556C>T, p.(Arg186Ter) and a deletion of exon 13-17 in RBL2 (NM_005611.3), establishing RBL2 as a candidate gene for an autosomal recessive neurodevelopmental disorder.
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Affiliation(s)
- Theresa Brunet
- Institute of Human Genetics, Faculty of Medicine, Technical University Munich, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | | | - Peter Lichtner
- Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Verena Kraus
- Department of Pediatrics, Klinik für Kinder- und Jugendmedizin, München Klinik Schwabing und Harlaching, Klinikum Rechts der Isar der Technischen Universität Munich, Munich, Germany
| | - Thomas Meitinger
- Institute of Human Genetics, Faculty of Medicine, Technical University Munich, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany
| | - Matias Wagner
- Institute of Human Genetics, Faculty of Medicine, Technical University Munich, Munich, Germany.,Institute of Human Genetics, Helmholtz Zentrum München, Neuherberg, Germany.,Institute for Neurogenomics, Helmholtz Zentrum München, Neuherberg, Germany
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6
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Scarr E, Udawela M, Dean B. Changed cortical risk gene expression in major depression and shared changes in cortical gene expression between major depression and bipolar disorders. Aust N Z J Psychiatry 2019; 53:1189-1198. [PMID: 31238704 DOI: 10.1177/0004867419857808] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
BACKGROUND Mood disorders likely occur in someone with a genetic predisposition who encounters a deleterious environmental factor leading to dysregulated physiological processes due to genetic mutations and epigenetic mechanisms altering gene expression. To gain data to support this hypothesis, we measured levels of gene expression in three cortical regions known to be affected by the pathophysiologies of major depression and bipolar disorders. METHODS Levels of RNA were measured using the Affymetrix™ Human Exon 1.0 ST Array in Brodmann's areas 9, 10 and 33 (left hemisphere) from individuals with major depression, bipolar disorder and age- and sex-matched controls with changed expression taken as a fold change in RNA ⩾1.2 at p < 0.01. Data were analysed using JMP® genomics 6.0 and the probable biological consequences of changes in gene expression determined using Core and Pathway Designer Analyses in Ingenuity Pathway Analysis. RESULTS There were altered levels of RNA in Brodmann's area 9 (major depression = 424; bipolar disorder = 331), Brodmann's area 10 (major depression = 52; bipolar disorder = 24) and Brodmann's area 33 (major depression = 59 genes; bipolar disorder = 38 genes) in mood disorders. No gene was differentially expressed in all three regions in either disorder. There was a high correlation between fold changes in levels of RNA from 112 genes in Brodmann's area 9 from major depression and bipolar disorder (r2 = 0.91, p < 0.001). Levels of RNA for four risk genes for major depression were lower in Brodmann's area 9 in that disorder. CONCLUSION Our data argue that there are complex regional-specific changes in cortical gene expression in major depression and bipolar disorder that includes the expression of some risk genes for major depression in those with that disorder. It could be hypothesised that the common changes in gene expression in major depression and bipolar disorder are involved in the genesis of symptoms common to both disorders.
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Affiliation(s)
- Elizabeth Scarr
- Molecular Psychiatry Laboratory, Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia.,CRC for Mental Health, Carlton, VIC, Australia.,Faculty of Veterinary and Agricultural Sciences, Melbourne Veterinary School, University of Melbourne, Melbourne, VIC, Australia
| | - Madhara Udawela
- Molecular Psychiatry Laboratory, Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia.,CRC for Mental Health, Carlton, VIC, Australia
| | - Brian Dean
- Molecular Psychiatry Laboratory, Florey Institute of Neuroscience and Mental Health, Parkville, VIC, Australia.,CRC for Mental Health, Carlton, VIC, Australia.,Centre for Mental Health, Faculty of Health, Arts and Design, Swinburne University, Hawthorne, VIC, Australia
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7
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Sasaki Y, Oshikawa M, Bharmoria P, Kouno H, Hayashi‐Takagi A, Sato M, Ajioka I, Yanai N, Kimizuka N. Near‐Infrared Optogenetic Genome Engineering Based on Photon‐Upconversion Hydrogels. Angew Chem Int Ed Engl 2019. [DOI: 10.1002/ange.201911025] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Affiliation(s)
- Yoichi Sasaki
- Department of Chemistry and Biochemistry Graduate School of Engineering Center for Molecular Systems (CMS) Kyushu University 744 Moto-oka, Nishi-ku Fukuoka 819-0395 Japan
| | - Mio Oshikawa
- Center for Brain Integration Research (CBIR) Tokyo Medical and Dental University (TMDU) 1-5-45 Yushima, Bunkyo-ku Tokyo 113–8510 Japan
| | - Pankaj Bharmoria
- Department of Chemistry and Biochemistry Graduate School of Engineering Center for Molecular Systems (CMS) Kyushu University 744 Moto-oka, Nishi-ku Fukuoka 819-0395 Japan
| | - Hironori Kouno
- Department of Chemistry and Biochemistry Graduate School of Engineering Center for Molecular Systems (CMS) Kyushu University 744 Moto-oka, Nishi-ku Fukuoka 819-0395 Japan
| | - Akiko Hayashi‐Takagi
- Laboratory of Medical Neuroscience Institute for Molecular and Cellular Regulation Gunma University Maebashi-city Gunma 371-8512 Japan
- PRESTO JST Honcho 4-1-8 Kawaguchi Saitama 332-0012 Japan
| | - Moritoshi Sato
- Graduate School of Arts and Sciences The University of Tokyo, Komaba, Meguro-ku Tokyo 153-8902 Japan
| | - Itsuki Ajioka
- Center for Brain Integration Research (CBIR) Tokyo Medical and Dental University (TMDU) 1-5-45 Yushima, Bunkyo-ku Tokyo 113–8510 Japan
- PRESTO JST Honcho 4-1-8 Kawaguchi Saitama 332-0012 Japan
| | - Nobuhiro Yanai
- Department of Chemistry and Biochemistry Graduate School of Engineering Center for Molecular Systems (CMS) Kyushu University 744 Moto-oka, Nishi-ku Fukuoka 819-0395 Japan
- PRESTO JST Honcho 4-1-8 Kawaguchi Saitama 332-0012 Japan
| | - Nobuo Kimizuka
- Department of Chemistry and Biochemistry Graduate School of Engineering Center for Molecular Systems (CMS) Kyushu University 744 Moto-oka, Nishi-ku Fukuoka 819-0395 Japan
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8
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Sasaki Y, Oshikawa M, Bharmoria P, Kouno H, Hayashi-Takagi A, Sato M, Ajioka I, Yanai N, Kimizuka N. Near-Infrared Optogenetic Genome Engineering Based on Photon-Upconversion Hydrogels. Angew Chem Int Ed Engl 2019; 58:17827-17833. [PMID: 31544993 DOI: 10.1002/anie.201911025] [Citation(s) in RCA: 72] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2019] [Indexed: 12/16/2022]
Abstract
Photon upconversion (UC) from near-infrared (NIR) light to visible light has enabled optogenetic manipulations in deep tissues. However, materials for NIR optogenetics have been limited to inorganic UC nanoparticles. Herein, NIR-light-triggered optogenetics using biocompatible, organic TTA-UC hydrogels is reported. To achieve triplet sensitization even in highly viscous hydrogel matrices, a NIR-absorbing complex is covalently linked with energy-pooling acceptor chromophores, which significantly elongates the donor triplet lifetime. The donor and acceptor are solubilized in hydrogels formed from biocompatible Pluronic F127 micelles, and heat treatment endows the excited triplets in the hydrogel with remarkable oxygen tolerance. Combined with photoactivatable Cre recombinase technology, NIR-light stimulation successfully performs genome engineering resulting in the formation of dendritic-spine-like structures of hippocampal neurons.
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Affiliation(s)
- Yoichi Sasaki
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Mio Oshikawa
- Center for Brain Integration Research (CBIR), Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan
| | - Pankaj Bharmoria
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Hironori Kouno
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
| | - Akiko Hayashi-Takagi
- Laboratory of Medical Neuroscience, Institute for Molecular and Cellular Regulation, Gunma University, Maebashi-city, Gunma, 371-8512, Japan.,PRESTO, JST, Honcho 4-1-8, Kawaguchi, Saitama, 332-0012, Japan
| | - Moritoshi Sato
- Graduate School of Arts and Sciences, The University of Tokyo, Komaba, Meguro-ku, Tokyo, 153-8902, Japan
| | - Itsuki Ajioka
- Center for Brain Integration Research (CBIR), Tokyo Medical and Dental University (TMDU), 1-5-45 Yushima, Bunkyo-ku, Tokyo, 113-8510, Japan.,PRESTO, JST, Honcho 4-1-8, Kawaguchi, Saitama, 332-0012, Japan
| | - Nobuhiro Yanai
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan.,PRESTO, JST, Honcho 4-1-8, Kawaguchi, Saitama, 332-0012, Japan
| | - Nobuo Kimizuka
- Department of Chemistry and Biochemistry, Graduate School of Engineering, Center for Molecular Systems (CMS), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka, 819-0395, Japan
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9
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Abstract
Differentiated neurons can undergo cell cycle re-entry during pathological conditions, but it remains largely accepted that M-phase is prohibited in these cells. Here we show that primary neurons at post-synaptogenesis stages of development can enter M-phase. We induced cell cycle re-entry by overexpressing a truncated Cyclin E isoform fused to Cdk2. Cyclin E/Cdk2 expression elicits canonical cell cycle checkpoints, which arrest cell cycle progression and trigger apoptosis. As in mitotic cells, checkpoint abrogation enables cell cycle progression through S and G2-phases into M-phase. Although most neurons enter M-phase, only a small subset undergo cell division. Alternatively, neurons can exit M-phase without cell division and recover the axon initial segment, a structural determinant of neuronal viability. We conclude that neurons and mitotic cells share S, G2 and M-phase regulation.
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10
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Oshikawa M, Okada K, Tabata H, Nagata KI, Ajioka I. Dnmt1-dependent Chk1 pathway suppression is protective against neuron division. Development 2017; 144:3303-3314. [PMID: 28928282 DOI: 10.1242/dev.154013] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/30/2017] [Accepted: 08/01/2017] [Indexed: 12/19/2022]
Abstract
Neuronal differentiation and cell-cycle exit are tightly coordinated, even in pathological situations. When pathological neurons re-enter the cell cycle and progress through the S phase, they undergo cell death instead of division. However, the mechanisms underlying mitotic resistance are mostly unknown. Here, we have found that acute inactivation of retinoblastoma (Rb) family proteins (Rb, p107 and p130) in mouse postmitotic neurons leads to cell death after S-phase progression. Checkpoint kinase 1 (Chk1) pathway activation during the S phase prevented the cell death, and allowed the division of cortical neurons that had undergone acute Rb family inactivation, oxygen-glucose deprivation (OGD) or in vivo hypoxia-ischemia. During neurogenesis, cortical neurons became protected from S-phase Chk1 pathway activation by the DNA methyltransferase Dnmt1, and underwent cell death after S-phase progression. Our results indicate that Chk1 pathway activation overrides mitotic safeguards and uncouples neuronal differentiation from mitotic resistance.
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Affiliation(s)
- Mio Oshikawa
- Center for Brain Integration Research (CBIR), Tokyo Medical and Dental University (TMDU), Tokyo 113-8510, Japan
| | - Kei Okada
- Center for Brain Integration Research (CBIR), Tokyo Medical and Dental University (TMDU), Tokyo 113-8510, Japan
| | - Hidenori Tabata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, Kasugai Aichi 480-0392, Japan
| | - Koh-Ichi Nagata
- Department of Molecular Neurobiology, Institute for Developmental Research, Aichi Human Service Center, Kasugai Aichi 480-0392, Japan
| | - Itsuki Ajioka
- Center for Brain Integration Research (CBIR), Tokyo Medical and Dental University (TMDU), Tokyo 113-8510, Japan .,The Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan
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11
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Khojah SM, Payne AP, McGuinness D, Shiels PG. Segmental Aging Underlies the Development of a Parkinson Phenotype in the AS/AGU Rat. Cells 2016; 5:E38. [PMID: 27763519 PMCID: PMC5187522 DOI: 10.3390/cells5040038] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2016] [Revised: 09/30/2016] [Accepted: 10/01/2016] [Indexed: 12/15/2022] Open
Abstract
There is a paucity of information on the molecular biology of aging processes in the brain. We have used biomarkers of aging (SA β-Gal, p16Ink4a, Sirt5, Sirt6, and Sirt7) to demonstrate the presence of an accelerated aging phenotype across different brain regions in the AS/AGU rat, a spontaneous Parkinsonian mutant of PKCγ derived from a parental AS strain. P16INK4a expression was significantly higher in AS/AGU animals compared to age-matched AS controls (p < 0.001) and displayed segmental expression across various brain regions. The age-related expression of sirtuins similarly showed differences between strains and between brain regions. Our data clearly show segmental aging processes within the rat brain, and that these are accelerated in the AS/AGU mutant. The accelerated aging, Parkinsonian phenotype, and disruption to dopamine signalling in the basal ganglia in AS/AGU rats, suggests that this rat strain represents a useful model for studies of development and progression of Parkinson's disease in the context of biological aging and may offer unique mechanistic insights into the biology of aging.
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Affiliation(s)
- Sohair M Khojah
- School of Life Sciences, Pharmacology Research Theme, University of Glasgow, Glasgow G12 8QQ, UK.
| | - Anthony P Payne
- School of Life Sciences, Pharmacology Research Theme, University of Glasgow, Glasgow G12 8QQ, UK.
| | - Dagmara McGuinness
- Wolfson Wohl Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow G61 1QH, UK.
| | - Paul G Shiels
- Wolfson Wohl Cancer Research Centre, Institute of Cancer Sciences, University of Glasgow, Glasgow G61 1QH, UK.
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12
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Vandenbosch R, Clark A, Fong BC, Omais S, Jaafar C, Dugal-Tessier D, Dhaliwal J, Lagace DC, Park DS, Ghanem N, Slack RS. RB regulates the production and the survival of newborn neurons in the embryonic and adult dentate gyrus. Hippocampus 2016; 26:1379-1392. [DOI: 10.1002/hipo.22613] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Renaud Vandenbosch
- Department of Cellular and Molecular Medicine; University of Ottawa Brain and Mind Research Institute, University of Ottawa; Ottawa ON Canada
| | - Alysen Clark
- Department of Cellular and Molecular Medicine; University of Ottawa Brain and Mind Research Institute, University of Ottawa; Ottawa ON Canada
| | - Bensun C. Fong
- Department of Cellular and Molecular Medicine; University of Ottawa Brain and Mind Research Institute, University of Ottawa; Ottawa ON Canada
| | - Saad Omais
- Department of Biology; American University of Beirut; Beirut Lebanon
| | - Carine Jaafar
- Department of Biology; American University of Beirut; Beirut Lebanon
| | - Delphie Dugal-Tessier
- Department of Cellular and Molecular Medicine; University of Ottawa Brain and Mind Research Institute, University of Ottawa; Ottawa ON Canada
| | - Jagroop Dhaliwal
- Department of Cellular and Molecular Medicine; University of Ottawa Brain and Mind Research Institute, University of Ottawa; Ottawa ON Canada
| | - Diane C. Lagace
- Department of Cellular and Molecular Medicine; University of Ottawa Brain and Mind Research Institute, University of Ottawa; Ottawa ON Canada
| | - David S. Park
- Department of Cellular and Molecular Medicine; University of Ottawa Brain and Mind Research Institute, University of Ottawa; Ottawa ON Canada
| | - Noël Ghanem
- Department of Biology; American University of Beirut; Beirut Lebanon
| | - Ruth S. Slack
- Department of Cellular and Molecular Medicine; University of Ottawa Brain and Mind Research Institute, University of Ottawa; Ottawa ON Canada
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13
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Cortical neurons gradually attain a post-mitotic state. Cell Res 2016; 26:1033-47. [PMID: 27325298 DOI: 10.1038/cr.2016.76] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2015] [Revised: 02/26/2016] [Accepted: 04/13/2016] [Indexed: 12/21/2022] Open
Abstract
Once generated, neurons are thought to permanently exit the cell cycle and become irreversibly differentiated. However, neither the precise point at which this post-mitotic state is attained nor the extent of its irreversibility is clearly defined. Here we report that newly born neurons from the upper layers of the mouse cortex, despite initiating axon and dendrite elongation, continue to drive gene expression from the neural progenitor tubulin α1 promoter (Tα1p). These observations suggest an ambiguous post-mitotic neuronal state. Whole transcriptome analysis of sorted upper cortical neurons further revealed that neurons continue to express genes related to cell cycle progression long after mitotic exit until at least post-natal day 3 (P3). These genes are however down-regulated thereafter, associated with a concomitant up-regulation of tumor suppressors at P5. Interestingly, newly born neurons located in the cortical plate (CP) at embryonic day 18-19 (E18-E19) and P3 challenged with calcium influx are found in S/G2/M phases of the cell cycle, and still able to undergo division at E18-E19 but not at P3. At P5 however, calcium influx becomes neurotoxic and leads instead to neuronal loss. Our data delineate an unexpected flexibility of cell cycle control in early born neurons, and describe how neurons transit to a post-mitotic state.
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14
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Ajioka I. Biomaterial-engineering and neurobiological approaches for regenerating the injured cerebral cortex. Regen Ther 2016; 3:63-67. [PMID: 31245474 PMCID: PMC6581816 DOI: 10.1016/j.reth.2016.02.002] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Revised: 01/08/2016] [Accepted: 02/12/2016] [Indexed: 01/07/2023] Open
Abstract
The cerebral cortex is responsible for higher functions of the central nervous system (CNS), such as movement, sensation, and cognition. When the cerebral cortex is severely injured, these functions are irreversibly impaired. Although recent neurobiological studies reveal that the cortex has the potential for regeneration, therapies for functional recovery face some technological obstacles. Biomaterials have been used to evoke regenerative potential and promote regeneration in several tissues, including the CNS. This review presents a brief overview of new therapeutic strategies for cortical regeneration from the perspectives of neurobiology and biomaterial engineering, and discusses a promising technology for evoking the regenerative potential of the cerebral cortex.
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Affiliation(s)
- Itsuki Ajioka
- Center for Brain Integration Research (CBIR), Tokyo Medical and Dental University (TMDU), Tokyo 113-8510, Japan,The Japan Science and Technology Agency (JST), Precursory Research for Embryonic Science and Technology (PRESTO), 4-1-8 Honcho, Kawaguchi, Saitama 332-0012, Japan,Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Tokyo 113-8510, Japan. Fax: +81 3 5803 4716.
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Ajioka I. Coordination of proliferation and neuronal differentiation by the retinoblastoma protein family. Dev Growth Differ 2014; 56:324-34. [PMID: 24697649 DOI: 10.1111/dgd.12127] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2014] [Revised: 02/13/2014] [Accepted: 02/16/2014] [Indexed: 12/23/2022]
Abstract
Once neurons enter the post-mitotic G0 phase during central nervous system (CNS) development, they lose their proliferative potential. When neurons re-enter the cell cycle during pathological situations such as neurodegeneration, they undergo cell death after S phase progression. Thus, the regulatory networks that drive cell proliferation and maintain neuronal differentiation are highly coordinated. In this review, the coordination of cell cycle control and neuronal differentiation during development are discussed, focusing on regulation by the Rb family of tumor suppressors (including p107 and p130), and the Cip/Kip family of cyclin dependent kinase (Cdk) inhibitors. Based on recent findings suggesting roles for these families in regulating neurogenesis and neuronal differentiation, I propose that the Rb family is essential for daughter cells of neuronal progenitors to enter the post-mitotic G0 phase without affecting the initiation of neuronal differentiation in most cases, while the Cip/Kip family regulates the timing of neuronal progenitor cell cycle exit and the initiation of neuronal differentiation at least in the progenitor cells of the cerebral cortex and the retina. Rb's lack of involvement in regulating the initiation of neuronal differentiation may explain why Rb family-deficient retinoblastomas characteristically exhibit neuronal features.
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Affiliation(s)
- Itsuki Ajioka
- Center for Brain Integration Research, Tokyo Medical and Dental University, 1-5-45 Yushima, Tokyo, 113-8510, Japan
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Inhibition of retinoblastoma mRNA degradation through Poly (A) involved in the neuroprotective effect of berberine against cerebral ischemia. PLoS One 2014; 9:e90850. [PMID: 24603897 PMCID: PMC3946351 DOI: 10.1371/journal.pone.0090850] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2013] [Accepted: 02/05/2014] [Indexed: 01/08/2023] Open
Abstract
Berberine is one kind of isoquinoline alkaloid with anti-apoptotic effects on the neurons suffering ischemia. To address the explanation for these activities, the berberine-induced cell cycle arrest during neurons suffering ischemia/reperfusion had been studied in the present study. According to the in vitro neurons with oxygen-glucose deprivation and in vivo ICR mice with cerebral ischemia/reperfusion, it was found that berberine could protect the mRNA of retinoblastoma (Rb) from degradation through its function on the poly(A) tail. The prolonged half-life of retinoblastoma 1 (gene of Rb, RB1) mRNA level secures the protein level of retinoblastoma, which facilitates cell cycle arrest of neurons in the process of ischemia/reperfusion and subsequently avoids cells entering in the apoptotic process. The poly(A) tail of RB1 mRNA, as a newly identified target of berberine, could help people focus on the interaction between berberine and mRNA to further understand the biological activities and functions of berberine.
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Oshikawa M, Okada K, Nakajima K, Ajioka I. Cortical excitatory neurons become protected from cell division during neurogenesis in an Rb family-dependent manner. J Cell Sci 2013. [DOI: 10.1242/jcs.135426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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