1
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Iegiani G, Ferraro A, Pallavicini G, Di Cunto F. The impact of TP53 activation and apoptosis in primary hereditary microcephaly. Front Neurosci 2023; 17:1220010. [PMID: 37457016 PMCID: PMC10338886 DOI: 10.3389/fnins.2023.1220010] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 06/12/2023] [Indexed: 07/18/2023] Open
Abstract
Autosomal recessive primary microcephaly (MCPH) is a constellation of disorders that share significant brain size reduction and mild to moderate intellectual disability, which may be accompanied by a large variety of more invalidating clinical signs. Extensive neural progenitor cells (NPC) proliferation and differentiation are essential to determine brain final size. Accordingly, the 30 MCPH loci mapped so far (MCPH1-MCPH30) encode for proteins involved in microtubule and spindle organization, centriole biogenesis, nuclear envelope, DNA replication and repair, underscoring that a wide variety of cellular processes is required for sustaining NPC expansion during development. Current models propose that altered balance between symmetric and asymmetric division, as well as premature differentiation, are the main mechanisms leading to MCPH. Although studies of cellular alterations in microcephaly models have constantly shown the co-existence of high DNA damage and apoptosis levels, these mechanisms are less considered as primary factors. In this review we highlight how the molecular and cellular events produced by mutation of the majority of MCPH genes may converge on apoptotic death of NPCs and neurons, via TP53 activation. We propose that these mechanisms should be more carefully considered in the alterations of the sophisticated equilibrium between proliferation, differentiation and death produced by MCPH gene mutations. In consideration of the potential druggability of cell apoptotic pathways, a better understanding of their role in MCPH may significantly facilitate the development of translational approaches.
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Affiliation(s)
- Giorgia Iegiani
- Department of Neuroscience ‘Rita Levi Montalcini’, University of Turin, Turin, Italy
- Neuroscience Institute Cavalieri Ottolenghi, Turin, Italy
| | - Alessia Ferraro
- Department of Neuroscience ‘Rita Levi Montalcini’, University of Turin, Turin, Italy
- Neuroscience Institute Cavalieri Ottolenghi, Turin, Italy
| | - Gianmarco Pallavicini
- Department of Neuroscience ‘Rita Levi Montalcini’, University of Turin, Turin, Italy
- Neuroscience Institute Cavalieri Ottolenghi, Turin, Italy
| | - Ferdinando Di Cunto
- Department of Neuroscience ‘Rita Levi Montalcini’, University of Turin, Turin, Italy
- Neuroscience Institute Cavalieri Ottolenghi, Turin, Italy
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2
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Shao Y, Zhou L, Li F, Zhao L, Zhang BL, Shao F, Chen JW, Chen CY, Bi X, Zhuang XL, Zhu HL, Hu J, Sun Z, Li X, Wang D, Rivas-González I, Wang S, Wang YM, Chen W, Li G, Lu HM, Liu Y, Kuderna LFK, Farh KKH, Fan PF, Yu L, Li M, Liu ZJ, Tiley GP, Yoder AD, Roos C, Hayakawa T, Marques-Bonet T, Rogers J, Stenson PD, Cooper DN, Schierup MH, Yao YG, Zhang YP, Wang W, Qi XG, Zhang G, Wu DD. Phylogenomic analyses provide insights into primate evolution. Science 2023; 380:913-924. [PMID: 37262173 DOI: 10.1126/science.abn6919] [Citation(s) in RCA: 28] [Impact Index Per Article: 28.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 01/26/2023] [Indexed: 06/03/2023]
Abstract
Comparative analysis of primate genomes within a phylogenetic context is essential for understanding the evolution of human genetic architecture and primate diversity. We present such a study of 50 primate species spanning 38 genera and 14 families, including 27 genomes first reported here, with many from previously less well represented groups, the New World monkeys and the Strepsirrhini. Our analyses reveal heterogeneous rates of genomic rearrangement and gene evolution across primate lineages. Thousands of genes under positive selection in different lineages play roles in the nervous, skeletal, and digestive systems and may have contributed to primate innovations and adaptations. Our study reveals that many key genomic innovations occurred in the Simiiformes ancestral node and may have had an impact on the adaptive radiation of the Simiiformes and human evolution.
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Affiliation(s)
- Yong Shao
- State Key Laboratory of Genetic Resources and Evolution, Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, China
| | - Long Zhou
- Center of Evolutionary & Organismal Biology, and Women's Hospital at Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Fang Li
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, DK-2100 Copenhagen, Denmark
- Institute of Animal Sex and Development, ZhejiangWanli University, Ningbo 315100, China
| | - Lan Zhao
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Bao-Lin Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, China
| | - Feng Shao
- Key Laboratory of Freshwater Fish Reproduction and Development (Ministry of Education), Southwest University School of Life Sciences, Chongqing 400715, China
| | | | - Chun-Yan Chen
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
| | - Xupeng Bi
- Center of Evolutionary & Organismal Biology, and Women's Hospital at Zhejiang University School of Medicine, Hangzhou 310058, China
| | - Xiao-Lin Zhuang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, China
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming 650204, China
| | | | - Jiang Hu
- Grandomics Biosciences, Beijing 102206, China
| | - Zongyi Sun
- Grandomics Biosciences, Beijing 102206, China
| | - Xin Li
- Grandomics Biosciences, Beijing 102206, China
| | - Depeng Wang
- Grandomics Biosciences, Beijing 102206, China
| | | | - Sheng Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, China
| | - Yun-Mei Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, China
| | - Wu Chen
- Guangzhou Zoo & Guangzhou Wildlife Research Center, Guangzhou 510070, China
| | - Gang Li
- College of Life Sciences, Shaanxi Normal University, Xi'an 710119, China
| | - Hui-Meng Lu
- School of Life Sciences, Northwestern Polytechnical University, Xi'an 710072, China
| | - Yang Liu
- College of Life Sciences, Shaanxi Normal University, Xi'an 710119, China
| | - Lukas F K Kuderna
- Institute of Evolutionary Biology (UPF-CSIC), PRBB, 08003 Barcelona, Spain
- Illumina Artificial Intelligence Laboratory, Illumina Inc, San Diego, CA 92122, USA
| | - Kyle Kai-How Farh
- Illumina Artificial Intelligence Laboratory, Illumina Inc, San Diego, CA 92122, USA
| | - Peng-Fei Fan
- School of Life Sciences, Sun Yat-sen University, Guangzhou, Guangdong 510275, China
| | - Li Yu
- State Key Laboratory for Conservation and Utilization of Bio-Resource in Yunnan, School of Life Sciences, Yunnan University, Kunming 650091, China
| | - Ming Li
- CAS Key Laboratory of Animal Ecology and Conservation Biology, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China
| | - Zhi-Jin Liu
- College of Life Sciences, Capital Normal University, Beijing 100048, China
| | - George P Tiley
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Anne D Yoder
- Department of Biology, Duke University, Durham, NC 27708, USA
| | - Christian Roos
- Gene Bank of Primates and Primate Genetics Laboratory, German Primate Center, Leibniz Institute for Primate Research, 37077 Göttingen, Germany
| | - Takashi Hayakawa
- Faculty of Environmental Earth Science, Hokkaido University, Sapporo, Hokkaido 060-0810, Japan
- Japan Monkey Centre, Inuyama, Aichi 484-0081, Japan
| | - Tomas Marques-Bonet
- Institute of Evolutionary Biology (UPF-CSIC), PRBB, 08003 Barcelona, Spain
- Catalan Institution of Research and Advanced Studies (ICREA), Passeig de Lluís Companys, 23, 08010 Barcelona, Spain
- CNAG-CRG, Centre for Genomic Regulation (CRG), Barcelona Institute of Science and Technology (BIST), 08028 Barcelona, Spain
- Institut Català de Paleontologia Miquel Crusafont, Universitat Autònoma de Barcelona, Edifici ICTA-ICP, c/ Columnes s/n, 08193 Cerdanyola del Vallès, Barcelona, Spain
| | - Jeffrey Rogers
- Human Genome Sequencing Center, Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Peter D Stenson
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK
| | - David N Cooper
- Institute of Medical Genetics, School of Medicine, Cardiff University, Cardiff CF14 4XN, UK
| | | | - Yong-Gang Yao
- Kunming College of Life Science, University of the Chinese Academy of Sciences, Kunming 650204, China
- Key Laboratory of Animal Models and Human Disease Mechanisms of Chinese Academy of Sciences & Yunnan Province, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650201, China
- National Resource Center for Non-Human Primates, Kunming Primate Research Center, and National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650107, China
| | - Ya-Ping Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650201, China
- National Resource Center for Non-Human Primates, Kunming Primate Research Center, and National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650107, China
| | - Wen Wang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, China
- School of Ecology and Environment, Northwestern Polytechnical University, Xi'an 710072, China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650201, China
| | - Xiao-Guang Qi
- Shaanxi Key Laboratory for Animal Conservation, College of Life Sciences, Northwest University, Xi'an 710069, China
| | - Guojie Zhang
- State Key Laboratory of Genetic Resources and Evolution, Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, China
- Center of Evolutionary & Organismal Biology, and Women's Hospital at Zhejiang University School of Medicine, Hangzhou 310058, China
- Section for Ecology and Evolution, Department of Biology, University of Copenhagen, DK-2100 Copenhagen, Denmark
- Liangzhu Laboratory, Zhejiang University Medical Center, Hangzhou 311121, China
| | - Dong-Dong Wu
- State Key Laboratory of Genetic Resources and Evolution, Kunming Natural History Museum of Zoology, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650201, China
- Center for Excellence in Animal Evolution and Genetics, Chinese Academy of Sciences, Kunming 650201, China
- National Resource Center for Non-Human Primates, Kunming Primate Research Center, and National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650107, China
- KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming 650204, China
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3
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Bolat H, Sağer SG, Türkyılmaz A, Çebi AH, Akın Y, Onay H, Özkınay F, Ünsel-Bolat G. Autosomal Recessive Primary Microcephaly (MCPH) and Novel Pathogenic Variants in ASPM and WDR62 Genes. Mol Syndromol 2022; 13:363-369. [PMID: 36588751 PMCID: PMC9801316 DOI: 10.1159/000524391] [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: 12/24/2021] [Accepted: 03/31/2022] [Indexed: 01/04/2023] Open
Abstract
Introduction Autosomal recessive primary microcephaly (MCPH) is a disorder characterized by congenital microcephaly and intellectual disability without extra-central nervous system malformation. MCPH is a disease with heterogeneity in genotype and phenotype. For this reason, it is important to determine the genetic causes and genotype-phenotype relationship in MCPH, which causes lifelong impairment. In this study, we aimed to evaluate the clinical, genetic, and brain imaging findings of cases diagnosed with MCPH. Methods Electroencephalogram and brain magnetic resonance imaging were performed for all cases. We evaluated genetic results of the 39 families including cases with suspected MCPH diagnosis. Results Genetic diagnosis related to MCPH was provided in 11/39 (28.2%) of these families including 13/41 cases (31.7%). Variants of the WDR62 gene were the most common (61.5%) cause, and variants of the ASPM gene were the second most common cause (38.5%). We have found 6 novel variants and 4 previously reported variants in ASPM and WDR62 genes. Main brain imaging findings in our cases were lissencephaly, polymicrogyria, schizencephaly, pachygyria, and cortical dysplasia. Genetic counseling in 2 families whose genetic diagnosis was determined prevented them from having another child with MCPH. Discussion/Conclusion Detection and reporting of novel variants is an important step in eliminating this disorder by providing families with appropriate genetic counseling.
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Affiliation(s)
- Hilmi Bolat
- Department of Medical Genetics, Balıkesir University Faculty of Medicine, Balıkesir, Turkey,*Hilmi Bolat,
| | - Safiye G. Sağer
- Clinics of Pediatric Neurology, Kartal Dr. Lütfi Kırdar City Hospital, Istanbul, Turkey
| | - Ayberk Türkyılmaz
- Department of Medical Genetics, Faculty of Medicine, Karadeniz Technical University Trabzon, Trabzon, Turkey
| | - Alper H. Çebi
- Department of Medical Genetics, Faculty of Medicine, Karadeniz Technical University Trabzon, Trabzon, Turkey
| | - Yasemin Akın
- Clinics of Pediatrics, Kartal Dr. Lütfi Kırdar City Hospital, Istanbul, Turkey
| | | | - Ferda Özkınay
- Department of Pediatrics, Division of Pediatric Genetics, Ege University Faculty of Medicine, Izmir, Turkey
| | - Gül Ünsel-Bolat
- Department of Child and Adolescent Psychiatry, Balıkesir University Faculty of Medicine, Balıkesir, Turkey,Department of Neuroscience, Ege University, Izmir, Turkey
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4
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Türkyılmaz A, Sager SG. Two New Cases of Primary Microcephaly with Neuronal Migration Defect Caused by Truncating Mutations in the ASPM Gene. Mol Syndromol 2022; 13:56-63. [PMID: 35221876 PMCID: PMC8832193 DOI: 10.1159/000516201] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2020] [Accepted: 03/29/2021] [Indexed: 08/22/2023] Open
Abstract
Autosomal recessive primary microcephaly (MCPH) is a uncommon disorder due to congenital deficiency in the development of the cerebral cortex, characterized by a head circumference below 2 SD. MCPH is a group of diseases with genetic heterogeneity and has been reported by the Online Mendelian Inheritance In Man® (OMIM) database and associated with 25 different genes. It is known that MCPH cases are most frequently associated with abnormal spindle-like, microcephaly-associated (ASPM) gene mutations. The ASPM protein consists of an N-terminal 81 IQ (isoleucine-glutamine) domain, a calponin-homology domain, and a C-terminal domain. It interacts with calmodulin and calmodulin-related proteins via the IQ domain and acts as a part in mitotic spindle function. The basic characteristics of cases with ASPM gene mutations are microcephaly (below -3 SD) present before 1 year of age, intellectual disability, and the absence of other congenital anomalies. Macroscopic organization of the brain is preserved in cases with ASPM mutation, and a decrease in brain volume, particularly gray matter volume loss and a simplified gyral pattern are observed. Cortical migration defects are a very rare finding in patients with ASPM mutations. In the present study, we aimed to discuss the clinical and genetic findings in 2 cases with cortical dysplasia in which truncated variants in the ASPM gene were detected, particularly in terms of genotype-phenotype correlation in comparison with the literature.
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Affiliation(s)
- Ayberk Türkyılmaz
- Department of Medical Genetics, Karadeniz Technical University Faculty of Medicine, Trabzon, Turkey
| | - Safiye Gunes Sager
- Department of Pediatric Neurology, Dr. Lutfi Kirdar City Hospital, İstanbul, Turkey
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5
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Baggiani M, Dell’Anno MT, Pistello M, Conti L, Onorati M. Human Neural Stem Cell Systems to Explore Pathogen-Related Neurodevelopmental and Neurodegenerative Disorders. Cells 2020; 9:E1893. [PMID: 32806773 PMCID: PMC7464299 DOI: 10.3390/cells9081893] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/07/2020] [Accepted: 08/09/2020] [Indexed: 12/18/2022] Open
Abstract
Building and functioning of the human brain requires the precise orchestration and execution of myriad molecular and cellular processes, across a multitude of cell types and over an extended period of time. Dysregulation of these processes affects structure and function of the brain and can lead to neurodevelopmental, neurological, or psychiatric disorders. Multiple environmental stimuli affect neural stem cells (NSCs) at several levels, thus impairing the normal human neurodevelopmental program. In this review article, we will delineate the main mechanisms of infection adopted by several neurotropic pathogens, and the selective NSC vulnerability. In particular, TORCH agents, i.e., Toxoplasma gondii, others (including Zika virus and Coxsackie virus), Rubella virus, Cytomegalovirus, and Herpes simplex virus, will be considered for their devastating effects on NSC self-renewal with the consequent neural progenitor depletion, the cellular substrate of microcephaly. Moreover, new evidence suggests that some of these agents may also affect the NSC progeny, producing long-term effects in the neuronal lineage. This is evident in the paradigmatic example of the neurodegeneration occurring in Alzheimer's disease.
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Affiliation(s)
- Matteo Baggiani
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, 56126 Pisa, Italy;
| | - Maria Teresa Dell’Anno
- Cellular Engineering Laboratory, Fondazione Pisana per la Scienza ONLUS, 56017 Pisa, Italy;
| | - Mauro Pistello
- Retrovirus Center and Virology Section, Department of Translational Research, University of Pisa and Virology Division, Pisa University Hospital, 56100 Pisa, Italy;
| | - Luciano Conti
- Department of Cellular, Computational and Integrative Biology—CIBIO, University of Trento, 38122 Trento, Italy;
| | - Marco Onorati
- Unit of Cell and Developmental Biology, Department of Biology, University of Pisa, 56126 Pisa, Italy;
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6
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Wang L, Li Z, Sievert D, Smith DEC, Mendes MI, Chen DY, Stanley V, Ghosh S, Wang Y, Kara M, Aslanger AD, Rosti RO, Houlden H, Salomons GS, Gleeson JG. Loss of NARS1 impairs progenitor proliferation in cortical brain organoids and leads to microcephaly. Nat Commun 2020; 11:4038. [PMID: 32788587 PMCID: PMC7424529 DOI: 10.1038/s41467-020-17454-4] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2019] [Accepted: 06/11/2020] [Indexed: 12/21/2022] Open
Abstract
Asparaginyl-tRNA synthetase1 (NARS1) is a member of the ubiquitously expressed cytoplasmic Class IIa family of tRNA synthetases required for protein translation. Here, we identify biallelic missense and frameshift mutations in NARS1 in seven patients from three unrelated families with microcephaly and neurodevelopmental delay. Patient cells show reduced NARS1 protein, impaired NARS1 activity and impaired global protein synthesis. Cortical brain organoid modeling shows reduced proliferation of radial glial cells (RGCs), leading to smaller organoids characteristic of microcephaly. Single-cell analysis reveals altered constituents of both astrocytic and RGC lineages, suggesting a requirement for NARS1 in RGC proliferation. Our findings demonstrate that NARS1 is required to meet protein synthetic needs and to support RGC proliferation in human brain development. Asparaginyl-tRNA synthetase1 (NARS1) is required for protein synthesis. Here, the authors identify biallelic NARS1 mutations in individuals with microcephaly and neurodevelopmental delay. Cortical brain organoid modeling recapitulates microcephaly characteristics and scRNA-seq reveals a role for NARS1 in radial glial cell proliferation.
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Affiliation(s)
- Lu Wang
- Department of Neurosciences, Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA, 92093, USA.,Rady Children's Institute for Genomic Medicine, Rady Children's Hospital, San Diego, CA, 92123, USA
| | - Zhen Li
- Department of Neurosciences, Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA, 92093, USA.,Rady Children's Institute for Genomic Medicine, Rady Children's Hospital, San Diego, CA, 92123, USA
| | - David Sievert
- Department of Neurosciences, Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA, 92093, USA.,Rady Children's Institute for Genomic Medicine, Rady Children's Hospital, San Diego, CA, 92123, USA
| | - Desirée E C Smith
- Metabolic Unit, Department of Clinical Chemistry, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam Gastroenterology & Metabolism, Amsterdam, Netherlands
| | - Marisa I Mendes
- Metabolic Unit, Department of Clinical Chemistry, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam Gastroenterology & Metabolism, Amsterdam, Netherlands
| | - Dillon Y Chen
- Rady Children's Institute for Genomic Medicine, Rady Children's Hospital, San Diego, CA, 92123, USA.,Department of Pediatrics, University of California San Diego, La Jolla, CA, 92093, USA.,Division of Child Neurology, Rady Children's Hospital, San Diego, CA, 92123, USA
| | - Valentina Stanley
- Department of Neurosciences, Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA, 92093, USA.,Rady Children's Institute for Genomic Medicine, Rady Children's Hospital, San Diego, CA, 92123, USA
| | - Shereen Ghosh
- Department of Neurosciences, Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA, 92093, USA.,Rady Children's Institute for Genomic Medicine, Rady Children's Hospital, San Diego, CA, 92123, USA
| | - Yulu Wang
- Laboratory of Biomanufacturing and Food Engineering, Institute of Food Science and Technology, Chinese Academy of Agricultural Sciences, Beijing, 100193, PR China
| | - Majdi Kara
- University of Tripoli, Tripoli Children's Hospital, Tripoli, Libya
| | | | - Rasim O Rosti
- Department of Neurosciences, Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA, 92093, USA.,Rady Children's Institute for Genomic Medicine, Rady Children's Hospital, San Diego, CA, 92123, USA
| | - Henry Houlden
- Department of Neuromuscular Disorders, UCL Institute of Neurology, Queen Square, London, WC1N 3BG, UK
| | - Gajja S Salomons
- Metabolic Unit, Department of Clinical Chemistry, Amsterdam UMC, Vrije Universiteit Amsterdam, Amsterdam Neuroscience, Amsterdam Gastroenterology & Metabolism, Amsterdam, Netherlands
| | - Joseph G Gleeson
- Department of Neurosciences, Howard Hughes Medical Institute, University of California San Diego, La Jolla, CA, 92093, USA. .,Rady Children's Institute for Genomic Medicine, Rady Children's Hospital, San Diego, CA, 92123, USA. .,Department of Pediatrics, University of California San Diego, La Jolla, CA, 92093, USA. .,Division of Child Neurology, Rady Children's Hospital, San Diego, CA, 92123, USA.
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7
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Naseer MI, Rasool M, Abdulkareem AA, Bassiouni RI, Algahtani H, Chaudhary AG, Al-Qahtani MH. Novel compound heterozygous mutations in MCPH1 gene causes primary microcephaly in Saudi family. ACTA ACUST UNITED AC 2019; 23:347-350. [PMID: 30351297 PMCID: PMC8015564 DOI: 10.17712/nsj.2018.4.20180095] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Objectives: To identify genetic variation involved in primary microcephaly. Methods: In present study we identified 4 generation Saudi family showing primary microcephaly. We performed whole exome sequencing along with Sanger sequencing to find the genetic defect in this family. This study was conducted in King Abdulaziz University started from 2016 and the results presented in this manuscript are from one of the family. Results: Two novel missense variants (c.982G>A and c.1273T>A) were identified in heterozygous state in exon 8 of MCPH1 gene. The detected missense variants cause a tyrosine to asparagine substitution of residue 425 and a valine to isoleucine substitution at residue 310. MCPH1 gene encodes a DNA damage response protein. The encoded protein play a role in G2/M DNA damage checkpoint arrest via maintenance of inhibitory phosphorylation of cyclin-dependent kinase 1. The respective mutation was ruled out in 100 control samples. Conclusion: We found novel compound heterozygous mutation in Saudi family that will help to build database for genetic mutations in population and pave way to devise strategies to tackle such disorders in future.
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Affiliation(s)
- Muhammad I Naseer
- Center of Excellence in Genomic Medicine Research, King Abdulaziz University, Jeddah, Kingdom of Saudi Arabia. E-mail:
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8
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Candelo E, Caicedo G, Rosso F, Ballesteros A, Orrego J, Escobar L, Lapunzina P, Nevado J, Pachajoa H. First report case with negative genetic study (array CGH, exome sequencing) in patients with vertical transmission of Zika virus infection and associated brain abnormalities. APPLICATION OF CLINICAL GENETICS 2019; 12:141-150. [PMID: 31440073 PMCID: PMC6679697 DOI: 10.2147/tacg.s190661] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/12/2018] [Accepted: 04/13/2019] [Indexed: 12/12/2022]
Abstract
Introduction Zika virus (ZIKV) is a little-known emerging mosquito-borne flavivirus. The perinatal ZIKV infection was associated with birth defects during the Brazilian outbreak. There was an increased risk of intrauterine transmission of the virus and a marked increase in the number of newborns with microcephaly. We report on two such cases. Case Report The first case was a 25-year-old pregnant woman from Colombia who became acutely ill with general symptoms during the tenth week of gestation, followed by severe generalized itching and maculopapular rash for approximately five days. This case was reported during the epidemic stage of the ZIKV infection in Colombia. At 23.3 gestational weeks, ultrasonography showed abnormal intracranial anatomy with cerebral ventriculomegaly, microcephaly, and parenchymal calcification. Given the grave prognosis, the patient elected to terminate the pregnancy at 25 gestational weeks. The second case was a 24-year-old pregnant woman who became acutely ill during the 17th week of gestation, which corresponded with the ZIKV epidemic in Colombia. At 30.5 gestational weeks, ultrasonography showed isolated fetal cerebral ventriculomegaly. We detected ZIKV in the amniotic fluid; however, the virus was not detected in the urine or serum of the mother or fetus. Tests for dengue virus, chikungunya virus, Toxoplasma gondii, rubella virus, cytomegalovirus, herpes simplex virus, HIV, hepatitis B and C, and parvovirus B19 were all negative. Different samples obtained from the placenta, amniotic liquid, and cerebrospinal fluid were positive for viral isolation of ZIKV RNA using TaqMan RT-PCR. Additionally, the parents and fetuses were tested for genetic diseases using whole exome sequencing and array CGH to rule out possible genetic syndromes that produce these congenital abnormalities. Conclusion These were the first cases in Colombia to show early vertical transmission of ZIKV and the first cases associated with congenital cerebral abnormalities in which molecular, infectious, and genomic tests were performed.
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Affiliation(s)
- Estephania Candelo
- Center for Research on Congenital Anomalies and Rare Diseases (CIACER), Department of Basic Medical Sciences, Universidad Icesi, Cali, Colombia.,MSc Biomaterials and Tissues Engineering and Genetics of Human Diseases, University College London, London, UK
| | - Gabriela Caicedo
- Center for Research on Congenital Anomalies and Rare Diseases (CIACER), Department of Basic Medical Sciences, Universidad Icesi, Cali, Colombia
| | - Fernando Rosso
- Infectology Department, Fundación Valle del Lili, Cali, Colombia
| | | | - Jaime Orrego
- Neonatal Department, Fundacion Valle del Lili, Cali, Colombia
| | - Luis Escobar
- Pathology Department, Fundacion Valle del Lili, Cali, Colombia
| | - Pablo Lapunzina
- Instituto de Genética Médica y Molecular (INGEMM), IdiPAZ, Hospital Universitario La Paz, Madrid, 28046, Spain.,CIBER de Enfermedades Raras (CIBERER), Madrid, ISCIII, Spain
| | - Julían Nevado
- Instituto de Genética Médica y Molecular (INGEMM), IdiPAZ, Hospital Universitario La Paz, Madrid, 28046, Spain.,CIBER de Enfermedades Raras (CIBERER), Madrid, ISCIII, Spain
| | - Harry Pachajoa
- Center for Research on Congenital Anomalies and Rare Diseases (CIACER), Department of Basic Medical Sciences, Universidad Icesi, Cali, Colombia.,Genetics Department, Fundacion Valle del Lili, Cali, Colombia
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9
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Li M, Yue W. VRK2, a Candidate Gene for Psychiatric and Neurological Disorders. MOLECULAR NEUROPSYCHIATRY 2018; 4:119-133. [PMID: 30643786 PMCID: PMC6323383 DOI: 10.1159/000493941] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/18/2018] [Accepted: 09/20/2018] [Indexed: 12/20/2022]
Abstract
Recent large-scale genetic approaches, such as genome-wide association studies, have identified multiple genetic variations that contribute to the risk of mental illnesses, among which single nucleotide polymorphisms (SNPs) within or near the vaccinia related kinase 2 (VRK2) gene have gained consistent support for their correlations with multiple psychiatric and neurological disorders including schizophrenia (SCZ), major depressive disorder (MDD), and genetic generalized epilepsy. For instance, the genetic variant rs1518395 in VRK2 showed genome-wide significant associations with SCZ (35,476 cases and 46,839 controls, p = 3.43 × 10-8) and MDD (130,620 cases and 347,620 controls, p = 4.32 × 10-12) in European populations. This SNP was also genome-wide significantly associated with SCZ in Han Chinese population (12,083 cases and 24,097 controls, p = 3.78 × 10-13), and all associations were in the same direction of allelic effects. These studies highlight the potential roles of VRK2 in the central nervous system, and this gene therefore might be a good candidate to investigate the shared genetic and molecular basis between SCZ and MDD, as it is one of the few genes known to show genome-wide significant associations with both illnesses. Furthermore, the VRK2 gene was found to be involved in multiple other congenital deficits related to the malfunction of neurodevelopment, adding further support for the involvement of this gene in the pathogenesis of these neurological and psychiatric illnesses. While the precise function of VRK2 in these conditions remains unclear, preliminary evidence suggests that it may affect neuronal proliferation and migration via interacting with multiple essential signaling pathways involving other susceptibility genes/proteins for psychiatric disorders. Here, we have reviewed the recent progress of genetic and molecular studies of VRK2, with an emphasis on its role in psychiatric illnesses and neurological functions. We believe that attention to this important gene is necessary, and further investigations of VRK2 may provide hints into the underlying mechanisms of SCZ and MDD.
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Affiliation(s)
- Ming Li
- Key Laboratory of Animal Models and Human Disease Mechanisms of the Chinese Academy of Sciences and Yunnan Province, Kunming Institute of Zoology, Kunming, China
- CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, China
| | - Weihua Yue
- Peking University Sixth Hospital/Institute of Mental Health, Beijing, China
- Key Laboratory of Mental Health, Ministry of Health (Peking University) and National Clinical Research Center for Mental Disorders (Peking University Sixth Hospital), Beijing, China
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10
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Functional characterization of biallelic RTTN variants identified in an infant with microcephaly, simplified gyral pattern, pontocerebellar hypoplasia, and seizures. Pediatr Res 2018; 84:435-441. [PMID: 29967526 PMCID: PMC6258334 DOI: 10.1038/s41390-018-0083-z] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 05/15/2018] [Accepted: 05/25/2018] [Indexed: 01/06/2023]
Abstract
BACKGROUND Biallelic deleterious variants in RTTN, which encodes rotatin, are associated with primary microcephaly, polymicrogyria, seizures, intellectual disability, and primordial dwarfism in human infants. METHODS AND RESULTS We performed exome sequencing of an infant with primary microcephaly, pontocerebellar hypoplasia, and intractable seizures and his healthy, unrelated parents. We cultured the infant's fibroblasts to determine primary ciliary phenotype. RESULTS We identified biallelic variants in RTTN in the affected infant: a novel missense variant and a rare, intronic variant that results in aberrant transcript splicing. Cultured fibroblasts from the infant demonstrated reduced length and number of primary cilia. CONCLUSION Biallelic variants in RTTN cause primary microcephaly in infants. Functional characterization of primary cilia length and number can be used to determine pathogenicity of RTTN variants.
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11
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Cherkaoui Jaouad I, Zrhidri A, Jdioui W, Lyahyai J, Raymond L, Egéa G, Taoudi M, El Mouatassim S, Sefiani A. A novel non sense mutation in WDR62 causes autosomal recessive primary microcephaly: a case report. BMC MEDICAL GENETICS 2018; 19:118. [PMID: 30021525 PMCID: PMC6052603 DOI: 10.1186/s12881-018-0625-6] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/21/2017] [Accepted: 06/13/2018] [Indexed: 11/25/2022]
Abstract
Background Autosomal recessive primary microcephaly (MCPH) is a rare genetically heterogeneous disorder of neurogenic brain development characterized by a reduced head circumference at birth with no remarkable anomalies of brain architecture and variable degrees of intellectual impairment. Clinical and genetic heterogeneity in genetic disorders represent a major diagnostic challenge. Case presentation Two patients, 11 and 9 years old, born from consanguineous parents, were referred to the department of medical genetics at the National Institute of Health in Rabat. The diagnosis of MCPH was made, based on reduced head circumference without brain architecture abnormalities. The two patients were subject to the whole-exome sequencing, which allowed to diagnose a novel homozygous mutation c.1027C > T; p.Gln343* in exon 8 of WDR62, a gene already known to be related to MCPH. Sanger sequencing confirmed the segregation of the mutation in the family. Conclusion Our data expends the spectrum of mutations in WDR62 gene, proves the efficiency and cost-effectiveness of whole exome sequencing for the molecular diagnosis of genetically heterogeneous disorders such MCPH. Exome sequencing led to the rapid and cost-effective identification of a novel homozygous mutation in WDR62 gene, thereby facilitating genetic counseling.
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Affiliation(s)
- Imane Cherkaoui Jaouad
- Centre de Génomique Humaine, Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Morocco. .,Département de Génétique Médicale, Institut National d'Hygiène, Rabat, Morocco.
| | - Abdelali Zrhidri
- Centre de Génomique Humaine, Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Morocco
| | - Wafaa Jdioui
- Centre de Génomique Humaine, Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Morocco.,Département de Génétique Médicale, Institut National d'Hygiène, Rabat, Morocco
| | - Jaber Lyahyai
- Centre de Génomique Humaine, Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Morocco
| | - Laure Raymond
- Département de Génétique Moléculaire, Laboratoire Biomnis, Lyon, France
| | - Grégory Egéa
- Département de Génétique Moléculaire, Laboratoire Biomnis, Lyon, France
| | - Mohamed Taoudi
- Département de Génétique Moléculaire, Laboratoire Biomnis, Lyon, France
| | | | - Abdelaziz Sefiani
- Centre de Génomique Humaine, Faculté de Médecine et de Pharmacie, Université Mohammed V, Rabat, Morocco.,Département de Génétique Médicale, Institut National d'Hygiène, Rabat, Morocco
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12
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Jiang K, Faltova L, Hua S, Capitani G, Prota AE, Landgraf C, Volkmer R, Kammerer RA, Steinmetz MO, Akhmanova A. Structural Basis of Formation of the Microtubule Minus-End-Regulating CAMSAP-Katanin Complex. Structure 2018; 26:375-382.e4. [DOI: 10.1016/j.str.2017.12.017] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2017] [Revised: 11/28/2017] [Accepted: 12/28/2017] [Indexed: 11/16/2022]
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13
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Auger N, Quach C, Healy-Profitós J, Lowe AM, Arbour L. Congenital microcephaly in Quebec: baseline prevalence, risk factors and outcomes in a large cohort of neonates. Arch Dis Child Fetal Neonatal Ed 2018; 103:F167-F172. [PMID: 28676560 DOI: 10.1136/archdischild-2016-311199] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/10/2016] [Revised: 03/24/2017] [Accepted: 05/27/2017] [Indexed: 01/28/2023]
Abstract
OBJECTIVE We assessed baseline prevalence, risk factors and outcomes of microcephaly in a large population of neonates. DESIGN Retrospective cohort study. SETTING All hospitals in the province of Quebec, Canada. PARTICIPANTS 794 microcephalic and 1 944 010 non-microcephalic infants born between 1989 and 2012. MAIN OUTCOME MEASURES Baseline prevalence of microcephaly and occurrence of other congenital anomalies. We estimated the association of (1) pregnancy risk factors including TORCH infections (toxoplasmosis, rubella, cytomegalovirus, herpes, other), exposure to teratogens, diabetes and maternal congenital anomalies with risk of microcephaly, and (2) microcephaly with risk of infant mortality and severe morbidity, adjusted for maternal characteristics. RESULTS The overall prevalence of microcephaly was 4.1 per 10 000, ranging between 3.0 and 5.3 per 10 000 over time. Only 37% of microcephalic infants presented with other congenital anomalies. Maternal infection during pregnancy was the strongest risk factor, with 32 times the risk of microcephaly (prevalence ratio 32.38; 95% CI 22.42 to 46.75) compared with no infection. Exposure to teratogens was the next most important risk factor, with three times greater risk (prevalence ratio 3.10; 95% CI 2.37 to 4.07). Microcephaly was associated with 20 times the risk of infant mortality compared with no microcephaly (prevalence ratio 20.52; 95% CI 15.57 to 27.04) and significantly greater infant morbidity. CONCLUSIONS In Canada, infectious exposure during pregnancy is a strong risk factor for microcephaly, and affected infants are at higher risk of poor birth outcomes. Better monitoring of microcephaly is needed in the event that Zika or other novel viruses affect future risk.
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Affiliation(s)
- Nathalie Auger
- University of Montreal Hospital Research Centre, Montreal, Canada.,Institut national de santé publique du Québec, Montreal, Canada
| | - Caroline Quach
- Institut national de santé publique du Québec, Montreal, Canada.,Sainte-Justine Hospital Research Centre, University of Montreal, Montreal, Canada
| | - Jessica Healy-Profitós
- University of Montreal Hospital Research Centre, Montreal, Canada.,Institut national de santé publique du Québec, Montreal, Canada
| | - Anne-Marie Lowe
- Institut national de santé publique du Québec, Montreal, Canada
| | - Laura Arbour
- Department of Medical Genetics, University of British Columbia, Vancouver, Canada
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14
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Chon AH, Mamey MR, Schrager SM, Vanderbilt DL, Chmait RH. The relationship between preoperative fetal head circumference and 2-year cognitive performance after laser surgery for twin-twin transfusion syndrome. Prenat Diagn 2018; 38:173-178. [PMID: 29314091 DOI: 10.1002/pd.5204] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Revised: 12/18/2017] [Accepted: 12/25/2017] [Indexed: 12/26/2022]
Abstract
OBJECTIVE To determine the relationship between preoperative fetal head circumference (HC) and cognitive performance among children treated with laser surgery for twin-twin transfusion syndrome (TTTS). METHODS Donor and recipient twin HCs were measured preoperatively (16-26 weeks' gestation) and at 2 years corrected age. Multilevel multivariate regression models were used to test pregnancy and child-level risk factors for lower Battelle Developmental Inventory Second Edition (BDI-2) scores. A repeated-measures ANOVA was used to examine HC growth among recipients and donors between preoperative and 2 years. RESULTS Ninety-nine children were evaluated. The average BDI-2 score for the cohort was 101.4 (SD = 12.2). After controlling for covariates, larger preoperative HC percentiles were significantly associated with an increase in total BDI-2 scores (β = 0.29; P < 0.001), where a 12.5% increase in preoperative HC percentile was associated with 1-point increase in total BDI-2 score. The mean recipient and donor twin HC percentiles preoperatively and at age 2 years were 51st percentile vs 20th percentile (P = .050) and 60th percentile vs 49th percentile (P = .676), respectively. CONCLUSION Smaller preoperative HC percentiles identified children at risk of lower, but still within normal range, total BDI-2 scores. The discordance in HC percentiles between the donor and recipient twin decreased after laser surgery.
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Affiliation(s)
- Andrew H Chon
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Mary Rose Mamey
- Department of Pediatrics, Division of Hospital Medicine, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Sheree M Schrager
- Department of Pediatrics, Division of Hospital Medicine, Children's Hospital Los Angeles, Los Angeles, CA, USA
| | - Douglas L Vanderbilt
- Department of Pediatrics, Division of General Pediatrics, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Ramen H Chmait
- Department of Obstetrics and Gynecology, Division of Maternal-Fetal Medicine, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
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15
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Replication of early and recent Zika virus isolates throughout mouse brain development. Proc Natl Acad Sci U S A 2017; 114:12273-12278. [PMID: 29087938 DOI: 10.1073/pnas.1714624114] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Fetal infection with Zika virus (ZIKV) can lead to congenital Zika virus syndrome (cZVS), which includes cortical malformations and microcephaly. The aspects of cortical development that are affected during virus infection are unknown. Using organotypic brain slice cultures generated from embryonic mice of various ages, sites of ZIKV replication including the neocortical proliferative zone and radial columns, as well as the developing midbrain, were identified. The infected radial units are surrounded by uninfected cells undergoing apoptosis, suggesting that programmed cell death may limit viral dissemination in the brain and may constrain virus-associated injury. Therefore, a critical aspect of ZIKV-induced neuropathology may be defined by death of uninfected cells. All ZIKV isolates assayed replicated efficiently in early and midgestation cultures, and two isolates examined replicated in late-gestation tissue. Alteration of neocortical cytoarchitecture, such as disruption of the highly elongated basal processes of the radial glial progenitor cells and impairment of postmitotic neuronal migration, were also observed. These data suggest that all lineages of ZIKV tested are neurotropic, and that ZIKV infection interferes with multiple aspects of neurodevelopment that contribute to the complexity of cZVS.
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16
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Pawitwar SS, Dhar S, Tiwari S, Ojha CR, Lapierre J, Martins K, Rodzinski A, Parira T, Paudel I, Li J, Dutta RK, Silva MR, Kaushik A, El-Hage N. Overview on the Current Status of Zika Virus Pathogenesis and Animal Related Research. J Neuroimmune Pharmacol 2017; 12:371-388. [PMID: 28444557 DOI: 10.1007/s11481-017-9743-8] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Accepted: 03/23/2017] [Indexed: 11/28/2022]
Abstract
There is growing evidence that Zika virus (ZIKV) infection is linked with activation of Guillan-Barré syndrome (GBS) in adults infected with the virus and microcephaly in infants following maternal infection. With the recent outpour in publications by numerous research labs, the association between microcephaly in newborns and ZIKV has become very apparent in which large numbers of viral particles were found in the central nervous tissue of an electively aborted microcephalic ZIKV-infected fetus. However, the underlying related mechanisms remain poorly understood. Thus, development of ZIKV-infected animal models are urgently required. The need to develop drugs and vaccines of high efficacy along with efficient diagnostic tools for ZIKV treatment and management raised the demand for a very selective animal model for exploring ZIKV pathogenesis and related mechanisms. In this review, we describe recent advances in animal models developed for studying ZIKV pathogenesis and evaluating potential interventions against human infection, including during pregnancy. The current research directions and the scientific challenges ahead in developing effective vaccines and therapeutics are also discussed.
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Affiliation(s)
- Shashank S Pawitwar
- Department of Cellular Biology and Pharmacology, Florida International University, Herbert Wertheim College of Medicine, Miami, FL, 33199, USA
| | - Supurna Dhar
- Department of Human and Molecular Genetics, Florida International University, Herbert Wertheim College of Medicine, Miami, FL, 33199, USA
| | - Sneham Tiwari
- Deparment of Immunology, Florida International University, Herbert Wertheim College of Medicine, Miami, FL, 33199, USA
| | - Chet Raj Ojha
- Deparment of Immunology, Florida International University, Herbert Wertheim College of Medicine, Miami, FL, 33199, USA
| | - Jessica Lapierre
- Deparment of Immunology, Florida International University, Herbert Wertheim College of Medicine, Miami, FL, 33199, USA
| | - Kyle Martins
- Department of Human and Molecular Genetics, Florida International University, Herbert Wertheim College of Medicine, Miami, FL, 33199, USA
| | - Alexandra Rodzinski
- Department of Cellular Biology and Pharmacology, Florida International University, Herbert Wertheim College of Medicine, Miami, FL, 33199, USA
| | - Tiyash Parira
- Deparment of Immunology, Florida International University, Herbert Wertheim College of Medicine, Miami, FL, 33199, USA
| | - Iru Paudel
- Department of Cellular Biology and Pharmacology, Florida International University, Herbert Wertheim College of Medicine, Miami, FL, 33199, USA
| | - Jiaojiao Li
- Department of Cellular Biology and Pharmacology, Florida International University, Herbert Wertheim College of Medicine, Miami, FL, 33199, USA
| | - Rajib Kumar Dutta
- Deparment of Immunology, Florida International University, Herbert Wertheim College of Medicine, Miami, FL, 33199, USA
| | - Monica R Silva
- Department of Cellular Biology and Pharmacology, Florida International University, Herbert Wertheim College of Medicine, Miami, FL, 33199, USA
| | - Ajeet Kaushik
- Deparment of Immunology, Florida International University, Herbert Wertheim College of Medicine, Miami, FL, 33199, USA
| | - Nazira El-Hage
- Deparment of Immunology, Florida International University, Herbert Wertheim College of Medicine, Miami, FL, 33199, USA.
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17
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Faizan MI, Abdullah M, Ali S, Naqvi IH, Ahmed A, Parveen S. Zika Virus-Induced Microcephaly and Its Possible Molecular Mechanism. Intervirology 2017; 59:152-158. [PMID: 28081529 DOI: 10.1159/000452950] [Citation(s) in RCA: 55] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Zika virus is an arthropod-borne re-emerging pathogen associated with the global pandemic of 2015-2016. The devastating effect of Zika viral infection is reflected by its neurological manifestations such as microcephaly in newborns. This scenario evoked our interest to uncover the neurotropic localization, multiplication of the virus, and the mechanism of microcephaly. The present report provides an overview of a possible molecular mechanism of Zika virus-induced microcephaly based on recent publications. Transplacental transmission of Zika viral infection from mother to foetus during the first trimester of pregnancy results in propagation of the virus in human neural progenitor cells (hNPCs), where entry is facilitated by the receptor (AXL protein) leading to the alteration of signalling and immune pathways in host cells. Further modification of the viral-induced TLR3-mediated immune network in the infected hNPCs affects viral replication. Downregulation of neurogenesis and upregulation of apoptosis in hNPCs leads to cell cycle arrest and death of the developing neurons. In addition, it is likely that the environmental, physiological, immunological, and genetic factors that determine in utero transmission of Zika virus are also involved in neurotropism. Despite the global concern regarding the Zika-mediated epidemic, the precise molecular mechanism of neuropathogenesis remains elusive.
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Affiliation(s)
- Md Imam Faizan
- Centre for Interdisciplinary Research in Basic Sciences, Jamia Millia Islamia, New Delhi, India
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18
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Kumar A, Singh HN, Pareek V, Raza K, Dantham S, Kumar P, Mochan S, Faiq MA. A Possible Mechanism of Zika Virus Associated Microcephaly: Imperative Role of Retinoic Acid Response Element (RARE) Consensus Sequence Repeats in the Viral Genome. Front Hum Neurosci 2016; 10:403. [PMID: 27555815 PMCID: PMC4977292 DOI: 10.3389/fnhum.2016.00403] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2016] [Accepted: 07/27/2016] [Indexed: 11/13/2022] Open
Abstract
Owing to the reports of microcephaly as a consistent outcome in the fetuses of pregnant women infected with ZIKV in Brazil, Zika virus (ZIKV)-microcephaly etiomechanistic relationship has recently been implicated. Researchers, however, are still struggling to establish an embryological basis for this interesting causal handcuff. The present study reveals robust evidence in favor of a plausible ZIKV-microcephaly cause-effect liaison. The rationale is based on: (1) sequence homology between ZIKV genome and the response element of an early neural tube developmental marker "retinoic acid" in human DNA and (2) comprehensive similarities between the details of brain defects in ZIKV-microcephaly and retinoic acid embryopathy. Retinoic acid is considered as the earliest factor for regulating anteroposterior axis of neural tube and positioning of structures in developing brain through retinoic acid response elements (RARE) consensus sequence (5'-AGGTCA-3') in promoter regions of retinoic acid-dependent genes. We screened genomic sequences of already reported virulent ZIKV strains (including those linked to microcephaly) and other viruses available in National Institute of Health genetic sequence database (GenBank) for the RARE consensus repeats and obtained results strongly bolstering our hypothesis that ZIKV strains associated with microcephaly may act through precipitation of dysregulation in retinoic acid-dependent genes by introducing extra stretches of RARE consensus sequence repeats in the genome of developing brain cells. Additional support to our hypothesis comes from our findings that screening of other viruses for RARE consensus sequence repeats is positive only for those known to display neurotropism and cause fetal brain defects (for which maternal-fetal transmission during developing stage may be required). The numbers of RARE sequence repeats appeared to match with the virulence of screened positive viruses. Although, bioinformatic evidence and embryological features are in favor of our hypothesis, additional studies including animal models are warranted to validate our proposition. Such studies are likely to unfold ZIKV-microcephaly association and may help in devising methods to combat it.
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Affiliation(s)
- Ashutosh Kumar
- Department of Anatomy, All India Institute of Medical Sciences New Delhi, India
| | - Himanshu N Singh
- Department of Biochemistry, All India Institute of Medical Sciences New Delhi, India
| | - Vikas Pareek
- Computational Neuroscience and Neuroimaging Division, National Brain Research Centre Manesar, India
| | - Khursheed Raza
- Department of Anatomy, All India Institute of Medical Sciences New Delhi, India
| | - Subrahamanyam Dantham
- Department of Biochemistry, All India Institute of Medical Sciences New Delhi, India
| | - Pavan Kumar
- Department of Anatomy, All India Institute of Medical Sciences New Delhi, India
| | - Sankat Mochan
- Department of Anatomy, All India Institute of Medical Sciences New Delhi, India
| | - Muneeb A Faiq
- Dr. Rajendra Prasad Centre for Ophthalmic Sciences, All India Institute of Medical SciencesNew Delhi, India; Laboratory for Molecular Reproduction and Genetics, Department of Anatomy, All India Institute of medical SciencesNew Delhi, India; Medical Biotechnology Laboratory, Dr. B. R. Ambedkar Centre for Biomedical Research, University of DelhiNew Delhi, India
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19
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Panchaud A, Stojanov M, Ammerdorffer A, Vouga M, Baud D. Emerging Role of Zika Virus in Adverse Fetal and Neonatal Outcomes. Clin Microbiol Rev 2016; 29:659-94. [PMID: 27281741 PMCID: PMC4978612 DOI: 10.1128/cmr.00014-16] [Citation(s) in RCA: 116] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The rapid spread of the Zika virus (ZIKV) in the Americas and its potential association with thousands of suspected cases of microcephaly in Brazil and higher rates of Guillain-Barré syndrome meet the conditions for a Public Health Emergency of International Concern, as stated by the World Health Organization in February 2016. Two months later, the Centers for Disease Control and Prevention (CDC) announced that the current available evidence supports the existence of a causal relationship between prenatal Zika virus infection and microcephaly and other serious brain anomalies. Microcephaly can be caused by several factors, and its clinical course and prognosis are difficult to predict. Other pathogens with proven teratogenicity have been identified long before the current ZIKV epidemic. Despite the growing number of cases with maternal signs of infection and/or presence of ZIKV in tissues of affected newborns or fetuses, it is currently difficult to assess the magnitude of increase of microcephaly prevalence in Brazil, as well as the role of other factors in the development of congenital neurological conditions. Meanwhile, health agencies and medical organizations have issued cautious guidelines advising health care practitioners and expectant couples traveling to, returning from, or living in affected areas. Analogous to dengue virus (DENV) epidemics, ZIKV has the potential to become endemic in all countries infested by Aedes mosquitoes, while new mutations could impact viral replication in humans, leading to increased virulence and consequently heightened chances of viral transmission to additional naive mosquito vectors. Studies are urgently needed to answer the questions surrounding ZIKV and its role in congenital neurological conditions.
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Affiliation(s)
- Alice Panchaud
- School of Pharmaceutical Sciences, University of Geneva and University of Lausanne, Geneva, Switzerland Department of Epidemiology, Harvard T. H. Chan School of Public Health, Boston, Massachusetts, USA Swiss Teratogen Information Service and Division of Clinical Pharmacology, University of Lausanne and University Hospital, Lausanne, Switzerland
| | - Miloš Stojanov
- Institute of Microbiology, Faculty of Biology and Medicine, University of Lausanne and University Hospital, Lausanne, Switzerland Materno-fetal and Obstetrics Research Unit, Department Femme-Mère-Enfant, University of Lausanne and University Hospital, Lausanne, Switzerland
| | - Anne Ammerdorffer
- Institute of Microbiology, Faculty of Biology and Medicine, University of Lausanne and University Hospital, Lausanne, Switzerland Materno-fetal and Obstetrics Research Unit, Department Femme-Mère-Enfant, University of Lausanne and University Hospital, Lausanne, Switzerland
| | - Manon Vouga
- Institute of Microbiology, Faculty of Biology and Medicine, University of Lausanne and University Hospital, Lausanne, Switzerland Materno-fetal and Obstetrics Research Unit, Department Femme-Mère-Enfant, University of Lausanne and University Hospital, Lausanne, Switzerland
| | - David Baud
- Institute of Microbiology, Faculty of Biology and Medicine, University of Lausanne and University Hospital, Lausanne, Switzerland Materno-fetal and Obstetrics Research Unit, Department Femme-Mère-Enfant, University of Lausanne and University Hospital, Lausanne, Switzerland
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20
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Nair P, Hamzeh AR, Mohamed M, Saif F, Tawfiq N, El Halik M, Al-Ali MT, Bastaki F. Microcephalic primordial dwarfism in an Emirati patient with PNKP mutation. Am J Med Genet A 2016; 170:2127-32. [PMID: 27232581 DOI: 10.1002/ajmg.a.37766] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Accepted: 05/09/2016] [Indexed: 11/11/2022]
Abstract
Microcephaly is a rare neurological condition, both in isolation and when it occurs as part of a syndrome. One of the syndromic forms of microcephaly is microcephaly, seizures and developmental delay (MCSZ) (OMIM #613402), a rare autosomal recessive neurodevelopmental disorder with a range of phenotypic severity, and known to be caused by mutations in the polynucleotide kinase 3' phosphatase (PNKP) gene. The PNK protein is a key enzyme involved in the repair of single and double stranded DNA breaks, a process which is particularly important in the nervous system. We describe an Emirati patient who presented with microcephaly, short stature, uncontrollable tonic-clonic seizures, facial dysmorphism, and developmental delay, while at the same time showing evidence of brain atrophy and agenesis of the corpus callosum. We used whole exome sequencing to identify homozygosity for a missense c.1385G > C (p.Arg462Pro) mutation in PNKP in the patient and heterozygosity for this mutation in her consanguineous parents. The Arg 462 residue forms a part of the lid subdomain helix of the P-loop Kinase domain. Although our patient's phenotype resembled that of MCSZ, the short stature and evidence of brain atrophy distinguished it from other classic cases of the condition. The report raises the question of whether to consider this case as an atypical variant of MCSZ or as a novel form of microcephalic primordial dwarfism. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
| | | | - Madiha Mohamed
- Pediatric Department, Latifa Hospital, Dubai Health Authority, Dubai, UAE
| | - Fatima Saif
- Pediatric Department, Latifa Hospital, Dubai Health Authority, Dubai, UAE
| | - Nafisa Tawfiq
- Pediatric Department, Latifa Hospital, Dubai Health Authority, Dubai, UAE
| | - Majdi El Halik
- Pediatric Department, Latifa Hospital, Dubai Health Authority, Dubai, UAE
| | | | - Fatma Bastaki
- Pediatric Department, Latifa Hospital, Dubai Health Authority, Dubai, UAE
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21
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Pervaiz N, Abbasi AA. Molecular evolution of WDR62, a gene that regulates neocorticogenesis. Meta Gene 2016; 9:1-9. [PMID: 27114917 PMCID: PMC4833054 DOI: 10.1016/j.mgene.2016.02.005] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 02/23/2016] [Indexed: 02/02/2023] Open
Abstract
Human brain evolution is characterized by dramatic expansion in cerebral cortex size. WDR62 (WD repeat domain 62) is one of the important gene in controlling human cortical development. Mutations in WDR62 lead to primary microcephaly, a neurodevelopmental disease characterized by three to four fold reduction in cerebral cortex size of affected individuals. This study analyzes comparative protein evolutionary rate to provide a useful insight into the molecular evolution of WDR62 and hence pinpointed human specific amino acid replacements. Comparative analysis of human WDR62 with two archaic humans (Neanderthals and Denisovans) and modern human populations revealed that five hominin specific amino acid residues (human specific amino acids shared with two archaic humans) might have been accumulated in the common ancestor of extinct archaic humans and modern humans about 550,000–765,000 years ago. Collectively, the data demonstrates an acceleration of WDR62 sequence evolution in hominin lineage and suggests that the ability of WDR62 protein to mediate the neurogenesis has been altered in the course of hominin evolution. We trace the evolutionary history of WDR62 and its putative paralogs. We identify accelerated sequence evolution in human WDR62. We pinpoint eight human specific amino acid sites that reside on the C-terminal. Out of eight, six sites are shared with archaic humans.
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Affiliation(s)
- Nashaiman Pervaiz
- National Center for Bioinformatics, Program of Comparative and Evolutionary Genomics, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan
| | - Amir Ali Abbasi
- National Center for Bioinformatics, Program of Comparative and Evolutionary Genomics, Faculty of Biological Sciences, Quaid-i-Azam University, Islamabad 45320, Pakistan
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22
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Pierzak-Sominka J, Skonieczna-Żydecka K, Rudnicki J, Karakiewicz B. The Impact of rs3762271 and rs930557 Polymorphisms of ASPM and MCPH1 Genes on the Anatomy and Function of the Brain. Biol Res Nurs 2016; 18:386-93. [PMID: 26912502 DOI: 10.1177/1099800416630621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
The ASPM and MCPH1 genes are involved in early neurogenesis and are thus potential candidates for affecting the formation of the anatomical and functional characteristics of the brain. However, the results of studies to date have been conflicting, an issue for which the factor of ethnicity may be responsible. We aimed to examine whether the rs3762271 and rs930557 polymorphisms of these two genes can influence brain anatomy and function. We enrolled 97 Caucasian neonates, with males predominating (53.6%). The anatomy of the brain was examined using ultrasound, while Doppler ultrasound was used to establish the blood flow indices in particular brain blood vessels. Genetic analysis was carried out using the polymerase chain reaction-restriction fragment length polymorphism method. The CC and AA homozygotes of rs3762271 were more common in males. The CC genotype of rs3762271 was significantly associated with birth weight (pRE = .03) and body length (pRE = .02). One mutant allele of rs3762271 was significantly associated with higher values of maximum (Vmax, p = .04), minimum (Vmin, p = .04), and average (Vmean, p = .02) speed in the pericallosal artery in newborns of both genders. Similar relationships were found in females only (Vmax p = .03, Vmean p = .02). The CC genotype of rs930557 was more frequently observed in male infants, but no impact on any anthropometric indices or anatomical and functional parameters of the brain was established. The ASPM gene may play a role in shaping the functional parameters of the brain in Caucasians.
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Affiliation(s)
| | | | - Jacek Rudnicki
- Department of Newborn Pathology, Pomeranian Medical University, Szczecin, Poland
| | - Beata Karakiewicz
- Department of Public Health, Pomeranian Medical University, Szczecin, Poland
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23
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Adaptive evolution of interleukin-3 (IL3), a gene associated with brain volume variation in general human populations. Hum Genet 2016; 135:377-392. [PMID: 26875095 DOI: 10.1007/s00439-016-1644-z] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 02/04/2016] [Indexed: 10/22/2022]
Abstract
Greatly expanded brain volume is one of the most characteristic traits that distinguish humans from other primates. Recent studies have revealed genes responsible for the dramatically enlarged human brain size (i.e., the microcephaly genes), and it has been well documented that many microcephaly genes have undergone accelerated evolution along the human lineage. In addition to being far larger than other primates, human brain volume is also highly variable in general populations. However, the genetic basis underlying human brain volume variation remains elusive and it is not known whether genes regulating human brain volume variation also have experienced positive selection. We have previously shown that genetic variants (near the IL3 gene) on 5q33 were significantly associated with brain volume in Chinese population. Here, we provide further evidence that support the significant association of genetic variants on 5q33 with brain volume. Bioinformatic analyses suggested that rs31480 is likely to be the causal variant among the studied SNPs. Molecular evolutionary analyses suggested that IL3 might have undergone positive selection in primates and humans. Neutrality tests further revealed signatures of positive selection of IL3 in Han Chinese and Europeans. Finally, extended haplotype homozygosity (EHH) and relative EHH analyses showed that the C allele of SNP rs31480 might have experienced recent positive selection in Han Chinese. Our results suggest that IL3 is an important genetic regulator for human brain volume variation and implied that IL3 might have experienced weak or modest positive selection in the evolutionary history of humans, which may be due to its contribution to human brain volume.
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24
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Hill EM, Petersen CP. Wnt/Notum spatial feedback inhibition controls neoblast differentiation to regulate reversible growth of the planarian brain. Development 2015; 142:4217-29. [PMID: 26525673 DOI: 10.1242/dev.123612] [Citation(s) in RCA: 55] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2015] [Accepted: 10/27/2015] [Indexed: 12/20/2022]
Abstract
Mechanisms determining final organ size are poorly understood. Animals undergoing regeneration or ongoing adult growth are likely to require sustained and robust mechanisms to achieve and maintain appropriate sizes. Planarians, well known for their ability to undergo whole-body regeneration using pluripotent adult stem cells of the neoblast population, can reversibly scale body size over an order of magnitude by controlling cell number. Using quantitative analysis, we showed that after injury planarians perfectly restored brain:body proportion by increasing brain cell number through epimorphosis or decreasing brain cell number through tissue remodeling (morphallaxis), as appropriate. We identified a pathway controlling a brain size set-point that involves feedback inhibition between wnt11-6/wntA/wnt4a and notum, encoding conserved antagonistic signaling factors expressed at opposite brain poles. wnt11-6/wntA/wnt4a undergoes feedback inhibition through canonical Wnt signaling but is likely to regulate brain size in a non-canonical pathway independently of beta-catenin-1 and APC. Wnt/Notum signaling tunes numbers of differentiated brain cells in regenerative growth and tissue remodeling by influencing the abundance of brain progenitors descended from pluripotent stem cells, as opposed to regulating cell death. These results suggest that the attainment of final organ size might be accomplished by achieving a balance of positional signaling inputs that regulate the rates of tissue production.
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Affiliation(s)
- Eric M Hill
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA
| | - Christian P Petersen
- Department of Molecular Biosciences, Northwestern University, Evanston, IL 60208, USA Robert Lurie Comprehensive Cancer Center, Northwestern University, Evanston, IL 60208, USA
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25
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Kodani A, Yu TW, Johnson JR, Jayaraman D, Johnson TL, Al-Gazali L, Sztriha L, Partlow JN, Kim H, Krup AL, Dammermann A, Krogan NJ, Walsh CA, Reiter JF. Centriolar satellites assemble centrosomal microcephaly proteins to recruit CDK2 and promote centriole duplication. eLife 2015; 4:e07519. [PMID: 26297806 PMCID: PMC4574112 DOI: 10.7554/elife.07519] [Citation(s) in RCA: 101] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2015] [Accepted: 08/21/2015] [Indexed: 12/23/2022] Open
Abstract
Primary microcephaly (MCPH) associated proteins CDK5RAP2, CEP152, WDR62 and CEP63 colocalize at the centrosome. We found that they interact to promote centriole duplication and form a hierarchy in which each is required to localize another to the centrosome, with CDK5RAP2 at the apex, and CEP152, WDR62 and CEP63 at sequentially lower positions. MCPH proteins interact with distinct centriolar satellite proteins; CDK5RAP2 interacts with SPAG5 and CEP72, CEP152 with CEP131, WDR62 with MOONRAKER, and CEP63 with CEP90 and CCDC14. These satellite proteins localize their cognate MCPH interactors to centrosomes and also promote centriole duplication. Consistent with a role for satellites in microcephaly, homozygous mutations in one satellite gene, CEP90, may cause MCPH. The satellite proteins, with the exception of CCDC14, and MCPH proteins promote centriole duplication by recruiting CDK2 to the centrosome. Thus, centriolar satellites build a MCPH complex critical for human neurodevelopment that promotes CDK2 centrosomal localization and centriole duplication.
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Affiliation(s)
- Andrew Kodani
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States
| | - Timothy W Yu
- Howard Hughes Medical Institute, Boston Children's Hospital, Boston, United States
| | - Jeffrey R Johnson
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
| | - Divya Jayaraman
- Howard Hughes Medical Institute, Boston Children's Hospital, Boston, United States
| | - Tasha L Johnson
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
| | - Lihadh Al-Gazali
- Department of Paediatrics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Lāszló Sztriha
- Department of Paediatrics, College of Medicine and Health Sciences, United Arab Emirates University, Al-Ain, United Arab Emirates
| | - Jennifer N Partlow
- Howard Hughes Medical Institute, Boston Children's Hospital, Boston, United States
| | - Hanjun Kim
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States
| | - Alexis L Krup
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States
| | | | - Nevan J Krogan
- Department of Cellular and Molecular Pharmacology, University of California, San Francisco, San Francisco, United States
| | - Christopher A Walsh
- Howard Hughes Medical Institute, Boston Children's Hospital, Boston, United States
| | - Jeremy F Reiter
- Department of Biochemistry and Biophysics, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, United States
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26
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Nebel RA, Kirschen J, Cai J, Woo YJ, Cherian K, Abrahams BS. Reciprocal Relationship between Head Size, an Autism Endophenotype, and Gene Dosage at 19p13.12 Points to AKAP8 and AKAP8L. PLoS One 2015; 10:e0129270. [PMID: 26076356 PMCID: PMC4468215 DOI: 10.1371/journal.pone.0129270] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2015] [Accepted: 05/06/2015] [Indexed: 12/30/2022] Open
Abstract
Microcephaly and macrocephaly are overrepresented in individuals with autism and are thought to be disease-related risk factors or endophenotypes. Analysis of DNA microarray results from a family with a low functioning autistic child determined that the proband and two additional unaffected family members who carry a rare inherited 760 kb duplication of unknown clinical significance at 19p13.12 are macrocephalic. Consideration alongside overlapping deletion and duplication events in the literature provides support for a strong relationship between gene dosage at this locus and head size, with losses and gains associated with microcephaly (p=1.11x10(-11)) and macrocephaly (p=2.47x10(-11)), respectively. Data support A kinase anchor protein 8 and 8-like (AKAP8 and AKAP8L) as candidate genes involved in regulation of head growth, an interesting finding given previous work implicating the AKAP gene family in autism. Towards determination of which of AKAP8 and AKAP8L may be involved in the modulation of head size and risk for disease, we analyzed exome sequencing data for 693 autism families (2591 individuals) where head circumference data were available. No predicted loss of function variants were observed, precluding insights into relationship to head size, but highlighting strong evolutionary conservation. Taken together, findings support the idea that gene dosage at 19p13.12, and AKAP8 and/or AKAP8L in particular, play an important role in modulation of head size and may contribute to autism risk. Exome sequencing of the family also identified a rare inherited variant predicted to disrupt splicing of TPTE / PTEN2, a PTEN homologue, which may likewise contribute to both macrocephaly and autism risk.
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Affiliation(s)
- Rebecca A. Nebel
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Jill Kirschen
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Department of Medicine, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Jinlu Cai
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Young Jae Woo
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, United States of America
| | - Koshi Cherian
- Saul R. Korey Department of Neurology, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, United States of America
- Epilepsy Management Center, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, United States of America
- Department of Pediatrics, Albert Einstein College of Medicine and Montefiore Medical Center, Bronx, New York, United States of America
| | - Brett S. Abrahams
- Department of Genetics, Albert Einstein College of Medicine, Bronx, New York, United States of America
- Dominick P. Purpura Department of Neuroscience, Albert Einstein College of Medicine, Bronx, New York, United States of America
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27
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Pan X, Chang X, Leung C, Zhou Z, Cao F, Xie W, Jia Z. PAK1 regulates cortical development via promoting neuronal migration and progenitor cell proliferation. Mol Brain 2015; 8:36. [PMID: 26043730 PMCID: PMC4456803 DOI: 10.1186/s13041-015-0124-z] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2015] [Accepted: 05/12/2015] [Indexed: 11/17/2022] Open
Abstract
Background p21-activated kinase 1 (PAK1) is a serine/threonine kinase known to be activated by the Rho family small GTPases and to play a key role in cytoskeletal reorganization, spine morphology and synaptic plasticity. PAK1 is also implicated in a number of neurodevelopmental and neurodegenerative diseases, including autism, intellectual disability and Alzheimer’s disease. However, the role of PAK1 in early brain development remains unknown. Results In this study, we employed genetic manipulations to investigate the role of PAK1 in the cerebral cortical development in mice. We showed that compared to the wild type littermates, PAK1 knockout mice have a reduction in the number of pyramidal neurons in several layers of the cerebral cortex, which is associated with a smaller pool of neural progenitor cells and impaired neuronal migration. Conclusion These results suggest that PAK1 regulates cortical development by promoting the proliferation of neural progenitor cells and facilitating the migration of these neurons to specific regions of the cortex.
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Affiliation(s)
- Xingxiu Pan
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, 2 Sipailou Road, 210096, Nanjing, China.
| | - Xinxia Chang
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, 2 Sipailou Road, 210096, Nanjing, China.
| | - Celeste Leung
- Neurosciences & Mental Health, The Hospital for Sick Children, 555 University Ave., M5G 1X8, Toronto, Ontario, Canada. .,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada.
| | - Zikai Zhou
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, 2 Sipailou Road, 210096, Nanjing, China.
| | - Feng Cao
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, 2 Sipailou Road, 210096, Nanjing, China. .,Neurosciences & Mental Health, The Hospital for Sick Children, 555 University Ave., M5G 1X8, Toronto, Ontario, Canada. .,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada.
| | - Wei Xie
- The Key Laboratory of Developmental Genes and Human Disease, Ministry of Education, Institute of Life Sciences, Jiangsu Co-innovation Center of Neuroregeneration, Southeast University, 2 Sipailou Road, 210096, Nanjing, China.
| | - Zhengping Jia
- Neurosciences & Mental Health, The Hospital for Sick Children, 555 University Ave., M5G 1X8, Toronto, Ontario, Canada. .,Department of Physiology, Faculty of Medicine, University of Toronto, Toronto, Canada.
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28
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Nakayama T, Al-Maawali A, El-Quessny M, Rajab A, Khalil S, Stoler JM, Tan WH, Nasir R, Schmitz-Abe K, Hill RS, Partlow JN, Al-Saffar M, Servattalab S, LaCoursiere CM, Tambunan DE, Coulter ME, Elhosary PC, Gorski G, Barkovich AJ, Markianos K, Poduri A, Mochida GH. Mutations in PYCR2, Encoding Pyrroline-5-Carboxylate Reductase 2, Cause Microcephaly and Hypomyelination. Am J Hum Genet 2015; 96:709-19. [PMID: 25865492 PMCID: PMC4570282 DOI: 10.1016/j.ajhg.2015.03.003] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2014] [Accepted: 03/05/2015] [Indexed: 12/27/2022] Open
Abstract
Despite recent advances in understanding the genetic bases of microcephaly, a large number of cases of microcephaly remain unexplained, suggesting that many microcephaly syndromes and associated genes have yet to be identified. Here, we report mutations in PYCR2, which encodes an enzyme in the proline biosynthesis pathway, as the cause of a unique syndrome characterized by postnatal microcephaly, hypomyelination, and reduced cerebral white-matter volume. Linkage mapping and whole-exome sequencing identified homozygous mutations (c.355C>T [p.Arg119Cys] and c.751C>T [p.Arg251Cys]) in PYCR2 in the affected individuals of two consanguineous families. A lymphoblastoid cell line from one affected individual showed a strong reduction in the amount of PYCR2. When mutant cDNAs were transfected into HEK293FT cells, both variant proteins retained normal mitochondrial localization but had lower amounts than the wild-type protein, suggesting that the variant proteins were less stable. A PYCR2-deficient HEK293FT cell line generated by genome editing with the clustered regularly interspaced short palindromic repeat (CRISPR)-Cas9 system showed that PYCR2 loss of function led to decreased mitochondrial membrane potential and increased susceptibility to apoptosis under oxidative stress. Morpholino-based knockdown of a zebrafish PYCR2 ortholog, pycr1b, recapitulated the human microcephaly phenotype, which was rescued by wild-type human PYCR2 mRNA, but not by mutant mRNAs, further supporting the pathogenicity of the identified variants. Hypomyelination and the absence of lax, wrinkly skin distinguishes this condition from that caused by previously reported mutations in the gene encoding PYCR2's isozyme, PYCR1, suggesting a unique and indispensable role for PYCR2 in the human CNS during development.
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Affiliation(s)
- Tojo Nakayama
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Almundher Al-Maawali
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Department of Genetics, College of Medicine and Health Science, Sultan Qaboos University, Muscat 123, Oman
| | - Malak El-Quessny
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA
| | - Anna Rajab
- National Genetics Center, Directorate General of Health Affairs, Ministry of Health, Muscat 113, Oman
| | - Samir Khalil
- Department of Pediatrics, Al-Makassed Islamic Charitable Society Hospital, Jerusalem 91220; Faculty of Medicine, Al-Quds University, Jerusalem 90612
| | - Joan M Stoler
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Wen-Hann Tan
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA
| | - Ramzi Nasir
- Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Division of Developmental Medicine, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA
| | - Klaus Schmitz-Abe
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - R Sean Hill
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA
| | - Jennifer N Partlow
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA
| | - Muna Al-Saffar
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Department of Paediatrics, College of Medicine and Health Sciences, United Arab Emirates University, PO Box 17666, Al-Ain, United Arab Emirates
| | - Sarah Servattalab
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA
| | | | - Dimira E Tambunan
- Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Michael E Coulter
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Harvard-MIT Division of Health Sciences and Technology, Cambridge, MA 02139, USA
| | - Princess C Elhosary
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Howard Hughes Medical Institute, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Grzegorz Gorski
- Cellular Neuroscience Core, F.M. Kirby Neurobiology Center, Boston Children's Hospital, Boston, MA 02115, USA
| | - A James Barkovich
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, San Francisco, CA 94143, USA
| | - Kyriacos Markianos
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Program in Medical and Population Genetics, Broad Institute of MIT and Harvard, Cambridge, MA 02142, USA
| | - Annapurna Poduri
- Department of Neurology, Boston Children's Hospital, Boston, MA 02115, USA; Epilepsy Genetics Program, Boston Children's Hospital, Boston, MA 02115, USA; Department of Neurology, Harvard Medical School, Boston, MA 02115, USA
| | - Ganeshwaran H Mochida
- Division of Genetics and Genomics, Department of Medicine, Boston Children's Hospital, Boston, MA 02115, USA; Manton Center for Orphan Disease Research, Boston Children's Hospital, Boston, MA 02115, USA; Department of Pediatrics, Harvard Medical School, Boston, MA 02115, USA; Pediatric Neurology Unit, Department of Neurology, Massachusetts General Hospital, Boston, MA 02114, USA.
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29
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Pulvers JN, Journiac N, Arai Y, Nardelli J. MCPH1: a window into brain development and evolution. Front Cell Neurosci 2015; 9:92. [PMID: 25870538 PMCID: PMC4376118 DOI: 10.3389/fncel.2015.00092] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2014] [Accepted: 02/28/2015] [Indexed: 12/21/2022] Open
Abstract
The development of the mammalian cerebral cortex involves a series of mechanisms: from patterning, progenitor cell proliferation and differentiation, to neuronal migration. Many factors influence the development of the cerebral cortex to its normal size and neuronal composition. Of these, the mechanisms that influence the proliferation and differentiation of neural progenitor cells are of particular interest, as they may have the greatest consequence on brain size, not only during development but also in evolution. In this context, causative genes of human autosomal recessive primary microcephaly, such as ASPM and MCPH1, are attractive candidates, as many of them show positive selection during primate evolution. MCPH1 causes microcephaly in mice and humans and is involved in a diverse array of molecular functions beyond brain development, including DNA repair and chromosome condensation. Positive selection of MCPH1 in the primate lineage has led to much insight and discussion of its role in brain size evolution. In this review, we will present an overview of MCPH1 from these multiple angles, and whilst its specific role in brain size regulation during development and evolution remain elusive, the pieces of the puzzle will be discussed with the aim of putting together the full picture of this fascinating gene.
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Affiliation(s)
| | - Nathalie Journiac
- U1141 Inserm Paris, France ; Université Paris Diderot, Sorbonne Paris Cité, UMRS 1141 Paris, France
| | - Yoko Arai
- Institut Jacques Monod, CNRS UMR 7592, Université Paris Diderot, Sorbonne Paris Cité Paris, France
| | - Jeannette Nardelli
- U1141 Inserm Paris, France ; Université Paris Diderot, Sorbonne Paris Cité, UMRS 1141 Paris, France
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Hong ST, Mah W. A Critical Role of GIT1 in Vertebrate and Invertebrate Brain Development. Exp Neurobiol 2015; 24:8-16. [PMID: 25792865 PMCID: PMC4363336 DOI: 10.5607/en.2015.24.1.8] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2015] [Revised: 02/14/2015] [Accepted: 02/14/2015] [Indexed: 11/20/2022] Open
Abstract
GIT1, a multifunctional signaling adaptor protein, is implicated in the development of dendritic spines and neuronal synapses. GIT1 forms a signaling complex with PIX, RAC, and PAK proteins that is known to play important roles in brain development. Here we found that Git1-knockout (Git1-/-) mice show a microcephaly-like small brain phenotype, which appears to be caused by reduced neuronal size rather than number. Git1-/- mice also show decreased dendritic spine number without morphological alterations in the hippocampus. Behaviorally, Git1-/- mice show impaired motor coordination and learning and memory. In addition, adult dGit Drosophila mutants show decreased brain size and abnormal morphology of the mushroom body. These results suggest that GIT1 is important for brain development in both rodents and flies.
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Affiliation(s)
- Sung-Tae Hong
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea
| | - Won Mah
- Department of Biological Sciences, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Korea. ; Department of Anatomy and Neurobiology, School of Dentistry, Kyungpook National University, Daegu, Korea
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Faheem M, Naseer MI, Rasool M, Chaudhary AG, Kumosani TA, Ilyas AM, Pushparaj P, Ahmed F, Algahtani HA, Al-Qahtani MH, Saleh Jamal H. Molecular genetics of human primary microcephaly: an overview. BMC Med Genomics 2015; 8 Suppl 1:S4. [PMID: 25951892 PMCID: PMC4315316 DOI: 10.1186/1755-8794-8-s1-s4] [Citation(s) in RCA: 154] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022] Open
Abstract
Autosomal recessive primary microcephaly (MCPH) is a neurodevelopmental disorder that is characterised by microcephaly present at birth and non-progressive mental retardation. Microcephaly is the outcome of a smaller but architecturally normal brain; the cerebral cortex exhibits a significant decrease in size. MCPH is a neurogenic mitotic disorder, though affected patients demonstrate normal neuronal migration, neuronal apoptosis and neural function. Twelve MCPH loci (MCPH1-MCPH12) have been mapped to date from various populations around the world and contain the following genes: Microcephalin, WDR62, CDK5RAP2, CASC5, ASPM, CENPJ, STIL, CEP135, CEP152, ZNF335, PHC1 and CDK6. It is predicted that MCPH gene mutations may lead to the disease phenotype due to a disturbed mitotic spindle orientation, premature chromosomal condensation, signalling response as a result of damaged DNA, microtubule dynamics, transcriptional control or a few other hidden centrosomal mechanisms that can regulate the number of neurons produced by neuronal precursor cells. Additional findings have further elucidated the microcephaly aetiology and pathophysiology, which has informed the clinical management of families suffering from MCPH. The provision of molecular diagnosis and genetic counselling may help to decrease the frequency of this disorder.
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Ronan L, Fletcher PC. From genes to folds: a review of cortical gyrification theory. Brain Struct Funct 2014; 220:2475-83. [PMID: 25511709 PMCID: PMC4549381 DOI: 10.1007/s00429-014-0961-z] [Citation(s) in RCA: 94] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2014] [Accepted: 12/06/2014] [Indexed: 01/05/2023]
Abstract
Cortical gyrification is not a random process. Instead, the folds that develop are synonymous with the functional organization of the cortex, and form patterns that are remarkably consistent across individuals and even some species. How this happens is not well understood. Although many developmental features and evolutionary adaptations have been proposed as the primary cause of gyrencephaly, it is not evident that gyrification is reducible in this way. In recent years, we have greatly increased our understanding of the multiple factors that influence cortical folding, from the action of genes in health and disease to evolutionary adaptations that characterize distinctions between gyrencephalic and lissencephalic cortices. Nonetheless it is unclear how these factors which influence events at a small-scale synthesize to form the consistent and biologically meaningful large-scale features of sulci and gyri. In this article, we review the empirical evidence which suggests that gyrification is the product of a generalized mechanism, namely the differential expansion of the cortex. By considering the implications of this model, we demonstrate that it is possible to link the fundamental biological components of the cortex to its large-scale pattern-specific morphology and functional organization.
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Affiliation(s)
- Lisa Ronan
- Brain Mapping Unit, Department of Psychiatry, University of Cambridge, Sir William Hardy Building, Downing Site, Downing Street, Cambridge, CB2 3EB, UK,
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Molecular and cellular basis of autosomal recessive primary microcephaly. BIOMED RESEARCH INTERNATIONAL 2014; 2014:547986. [PMID: 25548773 PMCID: PMC4274849 DOI: 10.1155/2014/547986] [Citation(s) in RCA: 75] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/16/2014] [Revised: 09/18/2014] [Accepted: 09/18/2014] [Indexed: 01/23/2023]
Abstract
Autosomal recessive primary microcephaly (MCPH) is a rare hereditary neurodevelopmental disorder characterized by a marked reduction in brain size and intellectual disability. MCPH is genetically heterogeneous and can exhibit additional clinical features that overlap with related disorders including Seckel syndrome, Meier-Gorlin syndrome, and microcephalic osteodysplastic dwarfism. In this review, we discuss the key proteins mutated in MCPH. To date, MCPH-causing mutations have been identified in twelve different genes, many of which encode proteins that are involved in cell cycle regulation or are present at the centrosome, an organelle crucial for mitotic spindle assembly and cell division. We highlight recent findings on MCPH proteins with regard to their role in cell cycle progression, centrosome function, and early brain development.
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Sahai I, Mochida GH, Grabowski EF, Caruso PA. Case records of the Massachusetts General Hospital. Case 27-2014. A 10-month-old boy with microcephaly and episodic cyanosis. N Engl J Med 2014; 371:847-58. [PMID: 25162892 DOI: 10.1056/nejmcpc1400833] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
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Khan MA, Rupp VM, Orpinell M, Hussain MS, Altmüller J, Steinmetz MO, Enzinger C, Thiele H, Höhne W, Nürnberg G, Baig SM, Ansar M, Nürnberg P, Vincent JB, Speicher MR, Gönczy P, Windpassinger C. A missense mutation in the PISA domain of HsSAS-6 causes autosomal recessive primary microcephaly in a large consanguineous Pakistani family. Hum Mol Genet 2014; 23:5940-9. [DOI: 10.1093/hmg/ddu318] [Citation(s) in RCA: 54] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023] Open
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Sun T, Hevner RF. Growth and folding of the mammalian cerebral cortex: from molecules to malformations. Nat Rev Neurosci 2014; 15:217-32. [PMID: 24646670 DOI: 10.1038/nrn3707] [Citation(s) in RCA: 340] [Impact Index Per Article: 34.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
The size and extent of folding of the mammalian cerebral cortex are important factors that influence a species' cognitive abilities and sensorimotor skills. Studies in various animal models and in humans have provided insight into the mechanisms that regulate cortical growth and folding. Both protein-coding genes and microRNAs control cortical size, and recent progress in characterizing basal progenitor cells and the genes that regulate their proliferation has contributed to our understanding of cortical folding. Neurological disorders linked to disruptions in cortical growth and folding have been associated with novel neurogenetic mechanisms and aberrant signalling pathways, and these findings have changed concepts of brain evolution and may lead to new medical treatments for certain disorders.
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Affiliation(s)
- Tao Sun
- Department of Cell and Developmental Biology, Weill Medical College of Cornell University, 1300 York Avenue, BOX 60, New York, New York 10065, USA
| | - Robert F Hevner
- Department of Neurological Surgery and Center for Integrative Brain Research, Seattle Children's Research Institute, Seattle, Washington 98101, USA
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Abnormal centrosome and spindle morphology in a patient with autosomal recessive primary microcephaly type 2 due to compound heterozygous WDR62 gene mutation. Orphanet J Rare Dis 2013; 8:178. [PMID: 24228726 PMCID: PMC4225825 DOI: 10.1186/1750-1172-8-178] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2013] [Accepted: 10/10/2013] [Indexed: 11/19/2022] Open
Abstract
Background Autosomal recessive primary microcephaly (MCPH) is a rare neurodevelopmental disease with severe microcephaly at birth due to a pronounced reduction in brain volume and intellectual disability. Biallelic mutations in the WD repeat-containing protein 62 gene WDR62 are the genetic cause of MCPH2. However, the exact underlying pathomechanism of MCPH2 remains to be clarified. Methods/results We characterized the clinical, radiological, and cellular features that add to the human MCPH2 phenotype. Exome sequencing followed by Sanger sequencing in a German family with two affected daughters with primary microcephaly revealed in the index patient the compound heterozygous mutations c.1313G>A (p.R438H) / c.2864-2867delACAG (p.D955Afs*112) of WDR62, the second of which is novel. Radiological examination displayed small frontal lobes, corpus callosum hypoplasia, simplified hippocampal gyration, and cerebellar hypoplasia. We investigated the cellular phenotype in patient-derived lymphoblastoid cells and compared it with that of healthy female controls. WDR62 expression in the patient’s immortalized lymphocytes was deranged, and mitotic spindle defects as well as abnormal centrosomal protein localization were apparent. Conclusion We propose that a disruption of centrosome integrity and/or spindle organization may play an important role in the development of microcephaly in MCPH2.
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Novorol C, Burkhardt J, Wood KJ, Iqbal A, Roque C, Coutts N, Almeida AD, He J, Wilkinson CJ, Harris WA. Microcephaly models in the developing zebrafish retinal neuroepithelium point to an underlying defect in metaphase progression. Open Biol 2013; 3:130065. [PMID: 24153002 PMCID: PMC3814721 DOI: 10.1098/rsob.130065] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023] Open
Abstract
Autosomal recessive primary microcephaly (MCPH) is a congenital disorder characterized by significantly reduced brain size and mental retardation. Nine genes are currently known to be associated with the condition, all of which encode centrosomal or spindle pole proteins. MCPH is associated with a reduction in proliferation of neural progenitors during fetal development. The cellular mechanisms underlying the proliferation defect, however, are not fully understood. The zebrafish retinal neuroepithelium provides an ideal system to investigate this question. Mutant or morpholino-mediated knockdown of three known MCPH genes (stil, aspm and wdr62) and a fourth centrosomal gene, odf2, which is linked to several MCPH proteins, results in a marked reduction in head and eye size. Imaging studies reveal a dramatic rise in the fraction of proliferating cells in mitosis in all cases, and time-lapse microscopy points to a failure of progression through prometaphase. There was also increased apoptosis in all the MCPH models but this appears to be secondary to the mitotic defect as we frequently saw mitotically arrested cells disappear, and knocking down p53 apoptosis did not rescue the mitotic phenotype, either in whole retinas or clones.
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Affiliation(s)
- Claire Novorol
- Department of Physiology, Development and Neuroscience, Cambridge University, Cambridge CB2 3DY, UK
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Reynolds JJ, Stewart GS. A single strand that links multiple neuropathologies in human disease. ACTA ACUST UNITED AC 2013; 136:14-27. [PMID: 23365091 DOI: 10.1093/brain/aws310] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022]
Abstract
The development of the human central nervous system is a complex process involving highly coordinated periods of neuronal proliferation, migration and differentiation. Disruptions in these neurodevelopmental processes can result in microcephaly, a neuropathological disorder characterized by a reduction in skull circumference and total brain volume, whereas a failure to maintain neuronal health in the adult brain can lead to progressive neurodegeneration. Defects in the cellular pathways that detect and repair DNA damage are a common cause of both these neuropathologies and are associated with a growing number of hereditary human disorders. In particular, defects in the repair of DNA single strand breaks, one of the most commonly occurring types of DNA lesion, have been associated with three neuropathological diseases: ataxia oculomotor apraxia 1, spinocerebellar ataxia with neuronal neuropathy 1 and microcephaly, early-onset, intractable seizures and developmental delay. A striking similarity between these three human diseases is that they are all caused by mutations in DNA end processing factors, suggesting that a particularly crucial stage of DNA single strand break repair is the repair of breaks with 'damaged' termini. Additionally all three disorders lack any extraneurological symptoms, such as immunodeficiency and cancer predisposition, which are typically found in other human diseases associated with defective DNA repair. However despite these similarities, two of these disorders present with progressive cerebellar degeneration, whereas the third presents with severe microcephaly. This review discusses the molecular defects behind these disorders and presents several hypotheses based on current literature on a number of important questions, in particular, how do mutations in different end processing factors within the same DNA repair pathway lead to such different neuropathologies?
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Affiliation(s)
- John J Reynolds
- School of Cancer Sciences, College of Medical and Dental Sciences, University of Birmingham, Birmingham B15 2TT, UK
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Kim BJ, Zaveri HP, Shchelochkov OA, Yu Z, Hernández-García A, Seymour ML, Oghalai JS, Pereira FA, Stockton DW, Justice MJ, Lee B, Scott DA. An allelic series of mice reveals a role for RERE in the development of multiple organs affected in chromosome 1p36 deletions. PLoS One 2013; 8:e57460. [PMID: 23451234 PMCID: PMC3581587 DOI: 10.1371/journal.pone.0057460] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2012] [Accepted: 01/24/2013] [Indexed: 01/28/2023] Open
Abstract
Individuals with terminal and interstitial deletions of chromosome 1p36 have a spectrum of defects that includes eye anomalies, postnatal growth deficiency, structural brain anomalies, seizures, cognitive impairment, delayed motor development, behavior problems, hearing loss, cardiovascular malformations, cardiomyopathy, and renal anomalies. The proximal 1p36 genes that contribute to these defects have not been clearly delineated. The arginine-glutamic acid dipeptide (RE) repeats gene (RERE) is located in this region and encodes a nuclear receptor coregulator that plays a critical role in embryonic development as a positive regulator of retinoic acid signaling. Rere-null mice die of cardiac failure between E9.5 and E11.5. This limits their usefulness in studying the role of RERE in the latter stages of development and into adulthood. To overcome this limitation, we created an allelic series of RERE-deficient mice using an Rere-null allele, om, and a novel hypomorphic Rere allele, eyes3 (c.578T>C, p.Val193Ala), which we identified in an N-ethyl-N-nitrosourea (ENU)-based screen for autosomal recessive phenotypes. Analyses of these mice revealed microphthalmia, postnatal growth deficiency, brain hypoplasia, decreased numbers of neuronal nuclear antigen (NeuN)-positive hippocampal neurons, hearing loss, cardiovascular malformations–aortic arch anomalies, double outlet right ventricle, and transposition of the great arteries, and perimembranous ventricular septal defects–spontaneous development of cardiac fibrosis and renal agenesis. These findings suggest that RERE plays a critical role in the development and function of multiple organs including the eye, brain, inner ear, heart and kidney. It follows that haploinsufficiency of RERE may contribute–alone or in conjunction with other genetic, environmental, or stochastic factors–to the development of many of the phenotypes seen in individuals with terminal and interstitial deletions that include the proximal region of chromosome 1p36.
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Affiliation(s)
- Bum Jun Kim
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Hitisha P. Zaveri
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Oleg A. Shchelochkov
- Department of Pediatrics, The University of Iowa, Iowa City, Iowa, United States of America
| | - Zhiyin Yu
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Andrés Hernández-García
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Michelle L. Seymour
- Huffington Center on Aging and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
| | - John S. Oghalai
- Department of Otolaryngology-Head and Neck Surgery, Stanford School of Medicine, Stanford, California, United State of America
| | - Fred A. Pereira
- Huffington Center on Aging and Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Otolaryngology–Head and Neck Surgery, Baylor College of Medicine, Houston, Texas, United States of America
| | - David W. Stockton
- Departments of Pediatrics and Internal Medicine, Wayne State University School of Medicine, Detroit, Michigan, United States of America
| | - Monica J. Justice
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
| | - Brendan Lee
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Howard Hughes Medical Institute, Baylor College of Medicine, Houston, Texas, United States of America
| | - Daryl A. Scott
- Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, Texas, United States of America
- Department of Molecular Physiology and Biophysics, Baylor College of Medicine, Houston, Texas, United States of America
- * E-mail:
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Montgomery SH, Mundy NI. Positive selection on NIN, a gene involved in neurogenesis, and primate brain evolution. GENES BRAIN AND BEHAVIOR 2012; 11:903-10. [PMID: 22937743 DOI: 10.1111/j.1601-183x.2012.00844.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2012] [Revised: 08/20/2012] [Accepted: 08/27/2012] [Indexed: 11/28/2022]
Abstract
A long-held dogma in comparative neurobiology has been that the number of neurons under a given area of cortical surface is constant. As such, the attention of those seeking to understand the genetic basis of brain evolution has focused on genes with functions in the lateral expansion of the developing cerebral cortex. However, new data suggest that cortical cytoarchitecture is not constant across primates, raising the possibility that changes in radial cortical development played a role in primate brain evolution. We present the first analysis of a gene with functions relevant to this dimension of brain evolution. We show that NIN, a gene necessary for maintaining asymmetric, neurogenic divisions of radial glial cells (RGCs), evolved adaptively during anthropoid evolution. We explored how this selection relates to neural phenotypes and find a significant association between selection on NIN and neonatal brain size in catarrhines. Our analyses suggest a relationship with prenatal neurogenesis and identify the human data point as an outlier, possibly explained by postnatal changes in development on the human lineage. A similar pattern is found in platyrrhines, but the highly encephalized genus Cebus departs from the general trend. We further show that the evolution of NIN may be associated with variation in neuron number not explained by increases in surface area, a result consistent with NIN's role in neurogenic divisions of RGCs. Our combined results suggest a role for NIN in the evolution of cortical development.
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Affiliation(s)
- S H Montgomery
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
| | - N I Mundy
- Department of Zoology, University of Cambridge, Cambridge, United Kingdom
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Liu X, Somel M, Tang L, Yan Z, Jiang X, Guo S, Yuan Y, He L, Oleksiak A, Zhang Y, Li N, Hu Y, Chen W, Qiu Z, Pääbo S, Khaitovich P. Extension of cortical synaptic development distinguishes humans from chimpanzees and macaques. Genome Res 2012; 22:611-22. [PMID: 22300767 DOI: 10.1101/gr.127324.111] [Citation(s) in RCA: 162] [Impact Index Per Article: 13.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Over the course of ontogenesis, the human brain and human cognitive abilities develop in parallel, resulting in a phenotype strikingly distinct from that of other primates. Here, we used microarrays and RNA-sequencing to examine human-specific gene expression changes taking place during postnatal brain development in the prefrontal cortex and cerebellum of humans, chimpanzees, and rhesus macaques. We show that the most prominent human-specific expression change affects genes associated with synaptic functions and represents an extreme shift in the timing of synaptic development in the prefrontal cortex, but not the cerebellum. Consequently, peak expression of synaptic genes in the prefrontal cortex is shifted from <1 yr in chimpanzees and macaques to 5 yr in humans. This result was supported by protein expression profiles of synaptic density markers and by direct observation of synaptic density by electron microscopy. Mechanistically, the human-specific change in timing of synaptic development involves the MEF2A-mediated activity-dependent regulatory pathway. Evolutionarily, this change may have taken place after the split of the human and the Neanderthal lineages.
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Affiliation(s)
- Xiling Liu
- Key Laboratory of Computational Biology, CAS-MPG Partner Institute for Computational Biology, Chinese Academy of Sciences, 200031 Shanghai, China
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Abstract
With the exception of the final stages of spermatogenesis in butterfly and some unicellular ciliates and flagellates, ciliated cells undergo cell division without cilia. This reciprocal relationship between cilia formation and cell division has prompted investigators to propose that ciliogenesis and cell cycle progression are mutually exclusive processes. Early work in fibroblasts showed that deciliation occurs in two waves, as cells depart from quiescence. The first wave of deciliation occurs before entry into S, while the second wave occurs between S and mitosis. Since then, it has remained a mystery whether and how (de)ciliation is coupled to the cell cycle and further, whether ciliation can affect cell cycle progression. Several recent publications provide evidence for a causative role of ciliary resorption in influencing the duration of the G1 phase of the cell cycle impacting on several developmental processes, including left-right patterning, kidney, skeletal and brain development. This body of work argues for the existence of a molecular crosstalk between ciliary factors and regulators of the cell cycle. Here, we review the evidence connecting primary cilia and the cell cycle and evaluate the idea that the primary cilium may function as a physical checkpoint in cell cycle re-entry.
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Affiliation(s)
- Sehyun Kim
- Department of Cell Biology, The University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
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Mahmood S, Ahmad W, Hassan MJ. Autosomal Recessive Primary Microcephaly (MCPH): clinical manifestations, genetic heterogeneity and mutation continuum. Orphanet J Rare Dis 2011; 6:39. [PMID: 21668957 PMCID: PMC3123551 DOI: 10.1186/1750-1172-6-39] [Citation(s) in RCA: 128] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2010] [Accepted: 06/13/2011] [Indexed: 12/21/2022] Open
Abstract
Autosomal Recessive Primary Microcephaly (MCPH) is a rare disorder of neurogenic mitosis characterized by reduced head circumference at birth with variable degree of mental retardation. In MCPH patients, brain size reduced to almost one-third of its original volume due to reduced number of generated cerebral cortical neurons during embryonic neurogensis. So far, seven genetic loci (MCPH1-7) for this condition have been mapped with seven corresponding genes (MCPH1, WDR62, CDK5RAP2, CEP152, ASPM, CENPJ, and STIL) identified from different world populations. Contribution of ASPM and WDR62 gene mutations in MCPH World wide is more than 50%. By and large, primary microcephaly patients are phenotypically indistinguishable, however, recent studies in patients with mutations in MCPH1, WDR62 and ASPM genes showed a broader clinical and/or cellular phenotype. It has been proposed that mutations in MCPH genes can cause the disease phenotype by disturbing: 1) orientation of mitotic spindles, 2) chromosome condensation mechanism during embryonic neurogenesis, 3) DNA damage-response signaling, 4) transcriptional regulations and microtubule dynamics, 5) certain unknown centrosomal mechanisms that control the number of neurons generated by neural precursor cells. Recent discoveries of mammalian models for MCPH have open up horizons for researchers to add more knowledge regarding the etiology and pathophysiology of MCPH. High incidence of MCPH in Pakistani population reflects the most probable involvement of consanguinity. Genetic counseling and clinical management through carrier detection/prenatal diagnosis in MCPH families can help reducing the incidence of this autosomal recessive disorder.
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Affiliation(s)
- Saqib Mahmood
- Department of Human Genetics and Molecular Biology, University of Health Sciences, Khayaban-e-Jamia Punjab, Lahore, 54600, Pakistan
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Adachi Y, Poduri A, Kawaguch A, Yoon G, Salih MA, Yamashita F, Walsh CA, Barkovich AJ. Congenital microcephaly with a simplified gyral pattern: associated findings and their significance. AJNR Am J Neuroradiol 2011; 32:1123-9. [PMID: 21454410 DOI: 10.3174/ajnr.a2440] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND AND PURPOSE Primary microcephaly is an incompletely understood malformation that is often associated with developmental brain anomalies, yet whether the associated anomalies result from the microcephaly itself or from associated developmental/genetic mishaps is not yet understood. This study reviewed and analyzed a large number of MR imaging scans of children with microcephaly to determine the frequency of associated morphologic findings and to assess whether these findings were associated with the severity of the microcephaly. MATERIALS AND METHODS MR images of 119 patients with clinically diagnosed microcephaly were retrospectively reviewed, focusing on the degree of microcephaly, simplification of gyri, white matter volume, abnormalities of the corpus callosum, size and structure of posterior fossa contents, and myelination. Associations among the findings were evaluated by using the Spearman correlation coefficient and the Fisher exact test. RESULTS Among 7 patients with mild, 42 with moderate, and 70 with extreme microcephaly, a significant correlation was identified between a greater degree of microcephaly and both a greater degree of simplified gyration and decreased white matter volume. The severity of the callosal anomaly showed a lower but still significant correlation with the severity of microcephaly. Degree of hypoplasia of posterior fossa structures, delay in myelination, and abnormality of the basal ganglia did not correlate with the degree of microcephaly. CONCLUSIONS A strong correlation was found between the degree of microcephaly, the volume of white matter, and the presence of a simplified gyral pattern. These associations should be considered when attempting to use neuroimaging for segregation and classification of patients with microcephaly.
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Affiliation(s)
- Y Adachi
- Department of Radiology and Biomedical Imaging, University of California, San Francisco, 94143, USA.
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p21-Activated kinases 1 and 3 control brain size through coordinating neuronal complexity and synaptic properties. Mol Cell Biol 2010; 31:388-403. [PMID: 21115725 DOI: 10.1128/mcb.00969-10] [Citation(s) in RCA: 96] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
The molecular mechanisms that coordinate postnatal brain enlargement, synaptic properties, and cognition remain an enigma. Here, we demonstrate that neuronal complexity controlled by p21-activated kinases (PAKs) is a key determinant for postnatal brain enlargement and synaptic properties. We showed that double-knockout (DK) mice lacking both PAK1 and PAK3 were born healthy, with normal brain size and structure, but severely impaired in postnatal brain growth, resulting in a dramatic reduction in brain volume. Remarkably, the reduced brain size was accompanied by minimal changes in total cell count, due to a significant increase in cell density. However, the DK neurons have smaller soma, markedly simplified dendritic arbors/axons, and reduced synapse density. Surprisingly, the DK mice had elevated basal synaptic responses due to enhanced individual synaptic potency but were severely impaired in bidirectional synaptic plasticity. The actions of PAK1 and PAK3 are possibly mediated by cofilin-dependent actin regulation, because the activity of cofilin and the properties of actin filaments were altered in the DK mice. These results reveal an essential in vivo role of PAK1 and PAK3 in coordinating neuronal complexity and synaptic properties and highlight the critical importance of dendrite/axon growth in dictating postnatal brain growth and attainment of normal brain size and function.
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50
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Bilgüvar K, Oztürk AK, Louvi A, Kwan KY, Choi M, Tatli B, Yalnizoğlu D, Tüysüz B, Cağlayan AO, Gökben S, Kaymakçalan H, Barak T, Bakircioğlu M, Yasuno K, Ho W, Sanders S, Zhu Y, Yilmaz S, Dinçer A, Johnson MH, Bronen RA, Koçer N, Per H, Mane S, Pamir MN, Yalçinkaya C, Kumandaş S, Topçu M, Ozmen M, Sestan N, Lifton RP, State MW, Günel M. Whole-exome sequencing identifies recessive WDR62 mutations in severe brain malformations. Nature 2010; 467:207-10. [PMID: 20729831 PMCID: PMC3129007 DOI: 10.1038/nature09327] [Citation(s) in RCA: 373] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2010] [Accepted: 06/30/2010] [Indexed: 11/12/2022]
Abstract
The development of the human cerebral cortex is an orchestrated process involving the birth of neural progenitors in the peri-ventricular germinal zones, cell proliferation characterized by both symmetric and asymmetric mitoses, followed by migration of post-mitotic neurons to their final destinations in 6 highly ordered, functionally-specialized layers1,2. An understanding of the molecular mechanisms guiding these intricate processes is in its infancy, substantially driven by the discovery of rare mutations that cause malformations of cortical development (MCD)3-6. Mapping of disease loci in putative Mendelian forms of MCD has been hindered by marked locus heterogeneity, small kindred sizes and diagnostic classifications that may not reflect molecular pathogenesis. Here we demonstrate the use of whole-exome sequencing to overcome these obstacles by identifying recessive mutations in WDR62 as the cause of a wide spectrum of severe cerebral cortical malformations including microcephaly, pachygria with cortical thickening as well as hypoplasia of the corpus callosum. Some patients with WDR62 mutations had evidence of additional abnormalities including lissencephaly, schizencephaly, polymicrogyria and, in one instance, cerebellar hypoplasia, all traits traditionally regarded as distinct entities. In mouse and humans, WDR62 transcripts and protein are enriched in neural progenitors within the ventricular and subventricular zones. WDR62 expression in the neocortex is transient, spanning the period of embryonic neurogenesis. Unlike other known microcephaly genes, WDR62 does not apparently associate with centrosomes and is predominantly nuclear in localization. These findings unify previously disparate aspects of cerebral cortical development and highlight the utility of whole-exome sequencing to identify disease loci in settings in which traditional methods have proved challenging.
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Affiliation(s)
- Kaya Bilgüvar
- Department of Neurosurgery, Yale University School of Medicine, New Haven, Connecticut 06510, USA
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