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Ki SM, Jeong HS, Lee JE. Primary Cilia in Glial Cells: An Oasis in the Journey to Overcoming Neurodegenerative Diseases. Front Neurosci 2021; 15:736888. [PMID: 34658775 PMCID: PMC8514955 DOI: 10.3389/fnins.2021.736888] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Accepted: 08/31/2021] [Indexed: 12/29/2022] Open
Abstract
Many neurodegenerative diseases have been associated with defects in primary cilia, which are cellular organelles involved in diverse cellular processes and homeostasis. Several types of glial cells in both the central and peripheral nervous systems not only support the development and function of neurons but also play significant roles in the mechanisms of neurological disease. Nevertheless, most studies have focused on investigating the role of primary cilia in neurons. Accordingly, the interest of recent studies has expanded to elucidate the role of primary cilia in glial cells. Correspondingly, several reports have added to the growing evidence that most glial cells have primary cilia and that impairment of cilia leads to neurodegenerative diseases. In this review, we aimed to understand the regulatory mechanisms of cilia formation and the disease-related functions of cilia, which are common or specific to each glial cell. Moreover, we have paid close attention to the signal transduction and pathological mechanisms mediated by glia cilia in representative neurodegenerative diseases. Finally, we expect that this field of research will clarify the mechanisms involved in the formation and function of glial cilia to provide novel insights and ideas for the treatment of neurodegenerative diseases in the future.
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Affiliation(s)
- Soo Mi Ki
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, South Korea
| | - Hui Su Jeong
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, South Korea
| | - Ji Eun Lee
- Department of Health Sciences and Technology, Samsung Advanced Institute for Health Sciences and Technology, Sungkyunkwan University, Seoul, South Korea.,Samsung Medical Center, Samsung Biomedical Research Institute, Seoul, South Korea
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2
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De Rosa MC, Glover HJ, Stratigopoulos G, LeDuc CA, Su Q, Shen Y, Sleeman MW, Chung WK, Leibel RL, Altarejos JY, Doege CA. Gene expression atlas of energy balance brain regions. JCI Insight 2021; 6:e149137. [PMID: 34283813 PMCID: PMC8409984 DOI: 10.1172/jci.insight.149137] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2023] Open
Abstract
Energy balance is controlled by interconnected brain regions in the hypothalamus, brainstem, cortex, and limbic system. Gene expression signatures of these regions can help elucidate the pathophysiology underlying obesity. RNA sequencing was conducted on P56 C57BL/6NTac male mice and E14.5 C57BL/6NTac embryo punch biopsies in 16 obesity-relevant brain regions. The expression of 190 known obesity-associated genes (monogenic, rare, and low-frequency coding variants; GWAS; syndromic) was analyzed in each anatomical region. Genes associated with these genetic categories of obesity had localized expression patterns across brain regions. Known monogenic obesity causal genes were highly enriched in the arcuate nucleus of the hypothalamus and developing hypothalamus. The obesity-associated genes clustered into distinct “modules” of similar expression profile, and these were distinct from expression modules formed by similar analysis with genes known to be associated with other disease phenotypes (type 1 and type 2 diabetes, autism, breast cancer) in the same energy balance–relevant brain regions.
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Affiliation(s)
- Maria Caterina De Rosa
- Department of Pediatrics and Molecular Genetics.,Naomi Berrie Diabetes Center, College of Physicians and Surgeons.,Columbia Stem Cell Initiative, and
| | - Hannah J Glover
- Department of Pediatrics and Molecular Genetics.,Naomi Berrie Diabetes Center, College of Physicians and Surgeons.,Columbia Stem Cell Initiative, and
| | - George Stratigopoulos
- Department of Pediatrics and Molecular Genetics.,Naomi Berrie Diabetes Center, College of Physicians and Surgeons
| | - Charles A LeDuc
- Department of Pediatrics and Molecular Genetics.,Naomi Berrie Diabetes Center, College of Physicians and Surgeons.,New York Obesity Nutrition Research Center, Department of Medicine, Columbia University Irving Medical Center, New York, New York, USA
| | - Qi Su
- Regeneron Pharmaceuticals Inc., Tarrytown, New York, USA
| | - Yufeng Shen
- Department of Systems Biology.,Department of Biomedical Informatics
| | - Mark W Sleeman
- Regeneron Pharmaceuticals Inc., Tarrytown, New York, USA
| | - Wendy K Chung
- Department of Pediatrics and Molecular Genetics.,Naomi Berrie Diabetes Center, College of Physicians and Surgeons.,Department of Medicine.,Herbert Irving Comprehensive Cancer Center.,Institute of Human Nutrition
| | - Rudolph L Leibel
- Department of Pediatrics and Molecular Genetics.,Naomi Berrie Diabetes Center, College of Physicians and Surgeons.,New York Obesity Nutrition Research Center, Department of Medicine, Columbia University Irving Medical Center, New York, New York, USA.,Institute of Human Nutrition
| | | | - Claudia A Doege
- Naomi Berrie Diabetes Center, College of Physicians and Surgeons.,Columbia Stem Cell Initiative, and.,New York Obesity Nutrition Research Center, Department of Medicine, Columbia University Irving Medical Center, New York, New York, USA.,Department of Pathology and Cell Biology, Columbia University Irving Medical Center, New York, New York, USA
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3
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Peterson SM, McGill TJ, Puthussery T, Stoddard J, Renner L, Lewis AD, Colgin LMA, Gayet J, Wang X, Prongay K, Cullin C, Dozier BL, Ferguson B, Neuringer M. Bardet-Biedl Syndrome in rhesus macaques: A nonhuman primate model of retinitis pigmentosa. Exp Eye Res 2019; 189:107825. [PMID: 31589838 DOI: 10.1016/j.exer.2019.107825] [Citation(s) in RCA: 30] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2019] [Revised: 09/27/2019] [Accepted: 09/30/2019] [Indexed: 11/15/2022]
Abstract
The development of therapies for retinal disorders is hampered by a lack of appropriate animal models. Higher nonhuman primates are the only animals with retinal structure similar to humans, including the presence of a macula and fovea. However, few nonhuman primate models of genetic retinal disease are known. We identified a lineage of rhesus macaques with a frameshift mutation in exon 3 of the BBS7 gene c.160delG (p.Ala54fs) that is predicted to produce a non-functional protein. In humans, mutations in this and other BBS genes cause Bardet-Biedl syndrome, a ciliopathy and a syndromic form of retinitis pigmentosa generally occurring in conjunction with kidney dysfunction, polydactyly, obesity, and/or hypogonadism. Three full- or half-sibling monkeys homozygous for the BBS7 c.160delG variant, at ages 3.5, 4 and 6 years old, displayed a combination of severe photoreceptor degeneration and progressive kidney disease. In vivo retinal imaging revealed features of severe macular degeneration, including absence of photoreceptor layers, degeneration of the retinal pigment epithelium, and retinal vasculature atrophy. Electroretinography in the 3.5-year-old case demonstrated loss of scotopic and photopic a-waves and markedly reduced and delayed b-waves. Histological assessments in the 4- and 6-year-old cases confirmed profound loss of photoreceptors and inner retinal neurons across the posterior retina, with dramatic thinning and disorganization of all cell layers, abundant microglia, absent or displaced RPE cells, and significant gliosis in the subretinal space. Retinal structure, including presence of photoreceptors, was preserved only in the far periphery. Ultrasound imaging of the kidneys revealed deranged architecture, and renal histopathology identified distorted contours with depressed, fibrotic foci and firmly adhered renal capsules; renal failure occurred in the 6-year-old case. Magnetic resonance imaging obtained in one case revealed abnormally low total brain volume and unilateral ventricular enlargement. The one male had abnormally small testes at 4 years of age, but polydactyly and obesity were not observed. Thus, monkeys homozygous for the BBS7 c.160delG variant closely mirrored several key features of the human BBS syndrome. This finding represents the first identification of a naturally-occurring nonhuman primate model of BBS, and more broadly the first such model of retinitis pigmentosa and a ciliopathy with an associated genetic mutation. This important new preclinical model will provide the basis for better understanding of disease progression and for the testing of new therapeutic options, including gene and cell-based therapies, not only for BBS but also for multiple forms of photoreceptor degeneration.
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Affiliation(s)
- Samuel M Peterson
- Division of Genetics, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Trevor J McGill
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA; Casey Eye Institute, Oregon Health & Sciences University, Portland, OR, 97239, USA.
| | - Teresa Puthussery
- School of Optometry & Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, 94720, USA.
| | - Jonathan Stoddard
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Lauren Renner
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Anne D Lewis
- Division of Comparative Medicine, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Lois M A Colgin
- Division of Comparative Medicine, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Jacqueline Gayet
- School of Optometry & Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, CA, 94720, USA.
| | - Xiaojie Wang
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA; Advanced Imaging Research Center, Oregon Health & Sciences University, Portland, OR, 97239, USA.
| | - Kamm Prongay
- Division of Comparative Medicine, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Cassandra Cullin
- Division of Comparative Medicine, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Brandy L Dozier
- Division of Comparative Medicine, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA.
| | - Betsy Ferguson
- Division of Genetics, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA; Department of Molecular and Medical Genetics, Oregon Health & Sciences University, Portland, OR, 97239, USA.
| | - Martha Neuringer
- Division of Neuroscience, Oregon National Primate Research Center, Oregon Health & Sciences University, Beaverton, OR, 97006, USA; Casey Eye Institute, Oregon Health & Sciences University, Portland, OR, 97239, USA.
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4
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Akinola OB, Gabriel MO. Neuroanatomical and molecular correlates of cognitive and behavioural outcomes in hypogonadal males. Metab Brain Dis 2018; 33:491-505. [PMID: 29230619 DOI: 10.1007/s11011-017-0163-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Accepted: 11/28/2017] [Indexed: 12/18/2022]
Abstract
Robust epidemiological, clinical and laboratory evidence supports emerging roles for the sex steroids in such domains as neurodevelopment, behaviour, learning and cognition. Regions of the mammalian brain that are involved in cognitive development and memory do not only express the classical nuclear androgen receptor, but also the non-genomic membrane receptor, which is a G protein-coupled receptor that mediates some rapid effects of the androgens on neurogenesis and synaptic plasticity. Under physiological conditions, hippocampal neurons do express the enzyme aromatase, and therefore actively aromatize testosterone to oestradiol. Although glial expression of the aromatase enzyme is minimal, increased expression following injury suggests a role for sex steroids in neuroprotection. It is therefore plausible to deduce that low levels of circulating androgens in males would perturb neuronal functions in relation to cognition and memory, as well as neural repair following injury. The present review is an overview of some roles of the sex steroids on cognitive function in males, and the neuroanatomical and molecular underpinnings of some behavioural and cognitive deficits characteristic of such genetic disorders noted for low androgen levels, including Klinefelter syndrome, Bardet-Biedl syndrome, Kallman syndrome and Prader-Willi syndrome. Recent literature in relation to some behavioural and cognitive changes secondary to surgical and pharmacological castration are also appraised.
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Affiliation(s)
- O B Akinola
- Division of Endocrinology, Department of Anatomy, Faculty of Basic Medical Sciences, College of Health Sciences, University of Ilorin, Ilorin, Nigeria.
| | - M O Gabriel
- Division of Endocrinology, Department of Anatomy, Faculty of Basic Medical Sciences, College of Health Sciences, University of Ilorin, Ilorin, Nigeria
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5
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Khan S, Muhammad N, Khan M, Kamal A, Rehman Z, Khan S. Genetics of human Bardet-Biedl syndrome, an updates. Clin Genet 2016; 90:3-15. [DOI: 10.1111/cge.12737] [Citation(s) in RCA: 98] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2015] [Revised: 12/21/2015] [Accepted: 01/03/2016] [Indexed: 12/22/2022]
Affiliation(s)
- S.A. Khan
- Department of Biotechnology and Genetic Engineering; Kohat University of Science and Technology; Khyber Pakhtunkhwa Pakistan
| | - N. Muhammad
- Department of Biotechnology and Genetic Engineering; Kohat University of Science and Technology; Khyber Pakhtunkhwa Pakistan
| | - M.A. Khan
- Gomal Centre of Biochemistry and Biotechnology; Gomal University; Khyber Pakhtunkhwa Pakistan
- Genomic Core Facility; Interim Translational Research Institute; Doha Qatar
| | - A. Kamal
- Department of Biotechnology and Genetic Engineering; Kohat University of Science and Technology; Khyber Pakhtunkhwa Pakistan
| | - Z.U. Rehman
- Department of Biotechnology and Genetic Engineering; Kohat University of Science and Technology; Khyber Pakhtunkhwa Pakistan
| | - S. Khan
- Department of Biotechnology and Genetic Engineering; Kohat University of Science and Technology; Khyber Pakhtunkhwa Pakistan
- Genomic Core Facility; Interim Translational Research Institute; Doha Qatar
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6
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Novas R, Cardenas-Rodriguez M, Irigoín F, Badano JL. Bardet-Biedl syndrome: Is it only cilia dysfunction? FEBS Lett 2015; 589:3479-91. [PMID: 26231314 DOI: 10.1016/j.febslet.2015.07.031] [Citation(s) in RCA: 62] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2015] [Revised: 07/14/2015] [Accepted: 07/15/2015] [Indexed: 01/12/2023]
Abstract
Bardet-Biedl syndrome (BBS) is a genetically heterogeneous, pleiotropic disorder, characterized by both congenital and late onset defects. From the analysis of the mutational burden in patients to the functional characterization of the BBS proteins, this syndrome has become a model for both understanding oligogenic patterns of inheritance and the biology of a particular cellular organelle: the primary cilium. Here we briefly review the genetics of BBS to then focus on the function of the BBS proteins, not only in the context of the cilium but also highlighting potential extra-ciliary roles that could be relevant to the etiology of the disorder. Finally, we provide an overview of how the study of this rare syndrome has contributed to the understanding of cilia biology and how this knowledge has informed on the cellular basis of different clinical manifestations that characterize BBS and the ciliopathies.
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Affiliation(s)
- Rossina Novas
- Human Molecular Genetics Laboratory, Institut Pasteur de Montevideo, Mataojo 2020, Montevideo CP11400, Uruguay
| | | | - Florencia Irigoín
- Human Molecular Genetics Laboratory, Institut Pasteur de Montevideo, Mataojo 2020, Montevideo CP11400, Uruguay; Departamento de Histología y Embriología, Facultad de Medicina, Universidad de la República, Montevideo, Gral. Flores 2125, Montevideo CP11800, Uruguay
| | - Jose L Badano
- Human Molecular Genetics Laboratory, Institut Pasteur de Montevideo, Mataojo 2020, Montevideo CP11400, Uruguay.
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7
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Guo J, Higginbotham H, Li J, Nichols J, Hirt J, Ghukasyan V, Anton ES. Developmental disruptions underlying brain abnormalities in ciliopathies. Nat Commun 2015. [PMID: 26206566 PMCID: PMC4515781 DOI: 10.1038/ncomms8857] [Citation(s) in RCA: 87] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Primary cilia are essential conveyors of signals underlying major cell functions. Cerebral cortical progenitors and neurons have a primary cilium. The significance of cilia function for brain development and function is evident in the plethora of developmental brain disorders associated with human ciliopathies. Nevertheless, the role of primary cilia function in corticogenesis remains largely unknown. Here we delineate the functions of primary cilia in the construction of cerebral cortex and their relevance to ciliopathies, using an shRNA library targeting ciliopathy genes known to cause brain disorders, but whose roles in brain development are unclear. We used the library to query how ciliopathy genes affect distinct stages of mouse cortical development, in particular neural progenitor development, neuronal migration, neuronal differentiation and early neuronal connectivity. Our results define the developmental functions of ciliopathy genes and delineate disrupted developmental events that are integrally related to the emergence of brain abnormalities in ciliopathies. Primary cilia are essential conveyors of signals underlying major cellular functions but their role in brain development is not completely understood. Here the authors compiled a shRNA library targeting ciliopathy genes known to cause brain disorders, and used it to query how ciliopathy genes affect distinct stages of mouse cortical development.
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Affiliation(s)
- Jiami Guo
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Holden Higginbotham
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Jingjun Li
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Jackie Nichols
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Josua Hirt
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - Vladimir Ghukasyan
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
| | - E S Anton
- UNC Neuroscience Center and the Department of Cell Biology and Physiology, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA
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8
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Braun JJ, Noblet V, Durand M, Scheidecker S, Zinetti-Bertschy A, Foucher J, Marion V, Muller J, Riehm S, Dollfus H, Kremer S. Olfaction evaluation and correlation with brain atrophy in Bardet-Biedl syndrome. Clin Genet 2014; 86:521-9. [DOI: 10.1111/cge.12391] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2013] [Revised: 03/26/2014] [Accepted: 03/27/2014] [Indexed: 11/26/2022]
Affiliation(s)
- J.-J. Braun
- Service ORL-CCF; Hôpitaux Universitaires de Strasbourg; Strasbourg France
| | - V. Noblet
- Laboratoire ICUBE, UMR CNRS 7357; Université de Strasbourg; Strasbourg France
| | - M. Durand
- Service de Génétique Médicale, Centre de Référence pour les Affections Rares en Génétique Ophtalmologique (CARGO); Hôpitaux Universitaires de Strasbourg; Strasbourg France
| | - S. Scheidecker
- Service de Génétique Médicale, Centre de Référence pour les Affections Rares en Génétique Ophtalmologique (CARGO); Hôpitaux Universitaires de Strasbourg; Strasbourg France
| | - A. Zinetti-Bertschy
- Pôle de Psychiatrie et Santé Mentale, Hôpitaux Universitaires de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg (FMTS); Université de Strasbourg; Strasbourg France
- Laboratoire de Neuropsychologie cognitive et physiopathologie de la schizophrénie, INSERM U1114, Fédération de Médecine Translationnelle de Strasbourg (FMTS); Université de Strasbourg; Strasbourg France
| | - J. Foucher
- Laboratoire ICUBE, UMR CNRS 7357; Université de Strasbourg; Strasbourg France
- Pôle de Psychiatrie et Santé Mentale, Hôpitaux Universitaires de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg (FMTS); Université de Strasbourg; Strasbourg France
| | - V. Marion
- Laboratoire de Génétique Médicale, INSERM U1112, Fédération de Médecine Translationnelle de Strasbourg (FMTS); Université de Strasbourg; Strasbourg France
| | - J. Muller
- Laboratoire ICUBE, UMR CNRS 7357; Université de Strasbourg; Strasbourg France
- Laboratoire de Diagnostic Génétique; Hôpitaux Universitaires de Strasbourg; Strasbourg France
- Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC), UMR 7104 and INSERM U964; Université de Strasbourg; Strasbourg France
| | - S. Riehm
- Service de Radiologie 1, Hôpitaux Universitaires de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg (FMTS); Université de Strasbourg; Strasbourg France
| | - H. Dollfus
- Service de Génétique Médicale, Centre de Référence pour les Affections Rares en Génétique Ophtalmologique (CARGO); Hôpitaux Universitaires de Strasbourg; Strasbourg France
- Laboratoire de Génétique Médicale, INSERM U1112, Fédération de Médecine Translationnelle de Strasbourg (FMTS); Université de Strasbourg; Strasbourg France
| | - S. Kremer
- Laboratoire ICUBE, UMR CNRS 7357; Université de Strasbourg; Strasbourg France
- Service de Radiologie 2, Hôpitaux Universitaires de Strasbourg, Fédération de Médecine Translationnelle de Strasbourg (FMTS); Université de Strasbourg; Strasbourg France
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9
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Agassandian K, Patel M, Agassandian M, Steren KE, Rahmouni K, Sheffield VC, Card JP. Ciliopathy is differentially distributed in the brain of a Bardet-Biedl syndrome mouse model. PLoS One 2014; 9:e93484. [PMID: 24695551 PMCID: PMC3973560 DOI: 10.1371/journal.pone.0093484] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2013] [Accepted: 03/06/2014] [Indexed: 01/21/2023] Open
Abstract
Bardet-Biedl syndrome (BBS) is a genetically heterogeneous inherited human disorder displaying a pleotropic phenotype. Many of the symptoms characterized in the human disease have been reproduced in animal models carrying deletions or knock-in mutations of genes causal for the disorder. Thinning of the cerebral cortex, enlargement of the lateral and third ventricles, and structural changes in cilia are among the pathologies documented in these animal models. Ciliopathy is of particular interest in light of recent studies that have implicated primary neuronal cilia (PNC) in neuronal signal transduction. In the present investigation, we tested the hypothesis that areas of the brain responsible for learning and memory formation would differentially exhibit PNC abnormalities in animals carrying a deletion of the Bbs4 gene (Bbs4-/-). Immunohistochemical localization of adenylyl cyclase-III (ACIII), a marker restricted to PNC, revealed dramatic alterations in PNC morphology and a statistically significant reduction in number of immunopositive cilia in the hippocampus and amygdala of Bbs4-/- mice compared to wild type (WT) littermates. Western blot analysis confirmed the decrease of ACIII levels in the hippocampus and amygdala of Bbs4-/- mice, and electron microscopy demonstrated pathological alterations of PNC in the hippocampus and amygdala. Importantly, no neuronal loss was found within the subregions of amygdala and hippocampus sampled in Bbs4-/- mice and there were no statistically significant alterations of ACIII immunopositive cilia in other areas of the brain not known to contribute to the BBS phenotype. Considered with data documenting a role of cilia in signal transduction these findings support the conclusion that alterations in cilia structure or neurochemical phenotypes may contribute to the cognitive deficits observed in the Bbs4-/- mouse mode.
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Affiliation(s)
- Khristofor Agassandian
- Department of Neuroscience, the University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
- * E-mail:
| | - Milan Patel
- Department of Neuroscience, the University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Marianna Agassandian
- Department of Medicine, the University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Karina E. Steren
- Department of Neuroscience, the University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
| | - Kamal Rahmouni
- Departments of Pharmacology and Internal Medicine, the University of Iowa, Iowa City, Iowa, United States of America
| | - Val C. Sheffield
- Department of Pediatrics, the University of Iowa, Iowa City, Iowa, United States of America
- Howard Hughes Medical Institute, University of Iowa, Iowa City, Iowa, United States of America
| | - J. Patrick Card
- Department of Neuroscience, the University of Pittsburgh, Pittsburgh, Pennsylvania, United States of America
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10
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Lee EB, Mattson MP. The neuropathology of obesity: insights from human disease. Acta Neuropathol 2014; 127:3-28. [PMID: 24096619 DOI: 10.1007/s00401-013-1190-x] [Citation(s) in RCA: 52] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2013] [Revised: 09/27/2013] [Accepted: 09/28/2013] [Indexed: 02/06/2023]
Abstract
Obesity, a pathologic state defined by excess adipose tissue, is a significant public health problem as it affects a large proportion of individuals and is linked with increased risk for numerous chronic diseases. Obesity is the result of fundamental changes associated with modern society including overnutrition and sedentary lifestyles. Proper energy homeostasis is dependent on normal brain function as the master metabolic regulator, which integrates peripheral signals, modulates autonomic outflow and controls feeding behavior. Therefore, many human brain diseases are associated with obesity. This review explores the neuropathology of obesity by examining brain diseases which either cause or are influenced by obesity. First, several genetic and acquired brain diseases are discussed as a means to understand the central regulation of peripheral metabolism. These diseases range from monogenetic causes of obesity (leptin deficiency, MC4R deficiency, Bardet-Biedl syndrome and others) to complex neurodevelopmental disorders (Prader-Willi syndrome and Sim1 deficiency) and neurodegenerative conditions (frontotemporal dementia and Gourmand's syndrome) and serve to highlight the central regulatory mechanisms which have evolved to maintain energy homeostasis. Next, to examine the effect of obesity on the brain, chronic neuropathologic conditions (epilepsy, multiple sclerosis and Alzheimer's disease) are discussed as examples of obesity leading to maladaptive processes which exacerbate chronic disease. Thus, obesity is associated with multiple pathways including abnormal metabolism, altered hormonal signaling and increased inflammation which act in concert to promote downstream neuropathology. Finally, the effect of anti-obesity interventions is discussed in terms of brain structure and function. Together, understanding human diseases and anti-obesity interventions leads to insights into the bidirectional interaction between peripheral metabolism and central brain function, highlighting the need for continued clinicopathologic and mechanistic studies of the neuropathology of obesity.
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11
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Sohár N, Jánossy Á, Janáky M, Facskó A. [Ophthalmologic manifestations of Bardet-Biedl syndrome]. Orv Hetil 2013; 154:2071-7. [PMID: 24374583 DOI: 10.1556/oh.2013.29748] [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: 11/19/2022]
Abstract
INTRODUCTION Bardet-Biedl syndrome is characterised by retinal dystrophy, polydactily, obesity and slow mental development. AIM The aim of the authors was to present ophthalmologic signs and symptoms of the syndrome. METHOD Between 1980 and 2010, 4 children with Bardet-Biedl syndrome were evaluated at the Department of Ophthalmology, University of Szeged, Szeged, Hungary. Their age at the first visit was between 1 and 10 years. Basic ophthalmological and electrophysiological evaluation, as well as orthoptic examinations were performed. RESULTS In two cases the electroretinographic curves were subnormal, and in two cases the electroretinographic curves showed no elevation. In the 4 children abnormal electroretinographic curves appeared at the ages of 1, 5, 10, and 18 years. Pigmentary changes on the periphery of the retina were detected in two cases. CONCLUSIONS The different signs and symptoms of Bardet-Biedl syndrome may manifest at different ages. Electrophysiological changes failed to correlate with retinal alterations is these patients.
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Affiliation(s)
- Nicolette Sohár
- Szegedi Tudományegyetem, Szent-Györgyi Albert Orvos- és Gyógyszerésztudományi Centrum, Általános Orvostudományi Kar Szemészeti Klinika Szeged Korányi fasor 10-11. 6720
| | - Ágnes Jánossy
- Szegedi Tudományegyetem, Szent-Györgyi Albert Orvos- és Gyógyszerésztudományi Centrum, Általános Orvostudományi Kar Szemészeti Klinika Szeged Korányi fasor 10-11. 6720
| | - Márta Janáky
- Szegedi Tudományegyetem, Szent-Györgyi Albert Orvos- és Gyógyszerésztudományi Centrum, Általános Orvostudományi Kar Szemészeti Klinika Szeged Korányi fasor 10-11. 6720
| | - Andrea Facskó
- Szegedi Tudományegyetem, Szent-Györgyi Albert Orvos- és Gyógyszerésztudományi Centrum, Általános Orvostudományi Kar Szemészeti Klinika Szeged Korányi fasor 10-11. 6720
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12
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Bisschoff IJ, Zeschnigk C, Horn D, Wellek B, Rieß A, Wessels M, Willems P, Jensen P, Busche A, Bekkebraten J, Chopra M, Hove HD, Evers C, Heimdal K, Kaiser AS, Kunstmann E, Robinson KL, Linné M, Martin P, McGrath J, Pradel W, Prescott KE, Roesler B, Rudolf G, Siebers-Renelt U, Tyshchenko N, Wieczorek D, Wolff G, Dobyns WB, Morris-Rosendahl DJ. Novel mutations including deletions of the entire OFD1 gene in 30 families with type 1 orofaciodigital syndrome: a study of the extensive clinical variability. Hum Mutat 2012; 34:237-47. [PMID: 23033313 DOI: 10.1002/humu.22224] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2012] [Accepted: 09/06/2012] [Indexed: 01/08/2023]
Abstract
OFD1, now recognized as a ciliopathy, is characterized by malformations of the face, oral cavity and digits, and is transmitted as an X-linked condition with lethality in males. Mutations in OFD1 also cause X-linked Joubert syndrome (JBTS10) and Simpson-Golabi-Behmel syndrome type 2 (SGBS2). We have studied 55 sporadic and six familial cases of suspected OFD1. Comprehensive mutation analysis in OFD1 revealed mutations in 37 female patients from 30 families; 22 mutations have not been previously described including two heterozygous deletions spanning OFD1 and neighbouring genes. Analysis of clinical findings in patients with mutations revealed that oral features are the most reliable diagnostic criteria. A first, detailed evaluation of brain MRIs from seven patients with cognitive defects illustrated extensive variability with the complete brain phenotype consisting of complete agenesis of the corpus callosum, large single or multiple interhemispheric cysts, striking cortical infolding of gyri, ventriculomegaly, mild molar tooth malformation and moderate to severe cerebellar vermis hypoplasia. Although the OFD1 gene apparently escapes X-inactivation, skewed inactivation was observed in seven of 14 patients. The direction of skewing did not correlate with disease severity, reinforcing the hypothesis that additional factors contribute to the extensive intrafamilial variability.
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Affiliation(s)
- Izak J Bisschoff
- Institute of Human Genetics, University Clinic Freiburg, Freiburg, Germany
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13
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Arellano JI, Guadiana SM, Breunig JJ, Rakic P, Sarkisian MR. Development and distribution of neuronal cilia in mouse neocortex. J Comp Neurol 2012; 520:848-73. [PMID: 22020803 DOI: 10.1002/cne.22793] [Citation(s) in RCA: 70] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Neuronal primary cilia are not generally recognized, but they are considered to extend from most, if not all, neurons in the neocortex. However, when and how cilia develop in neurons are not known. This study used immunohistochemistry for adenylyl cyclase III (ACIII), a marker of primary cilia, and electron microscopic analysis to describe the development and maturation of cilia in mouse neocortical neurons. Our results indicate that ciliogenesis is initiated in late fetal stages after neuroblast migration, when the mother centriole docks with the plasma membrane, becomes a basal body, and grows a cilia bud that we call a procilium. This procilium consists of a membranous protrusion extending from the basal body but lacking axonemal structure and remains undifferentiated until development of the axoneme and cilia elongation starts at about postnatal day 4. Neuronal cilia elongation and final cilia length depend on layer position, and the process extends for a long time, lasting 8-12 weeks. We show that, in addition to pyramidal neurons, inhibitory interneurons also grow cilia of comparable length, suggesting that cilia are indeed present in all neocortical neuron subtypes. Furthermore, the study of mice with defective ciliogenesis suggested that failed elongation of cilia is not essential for proper neuronal migration and laminar organization or establishment of neuronal polarity. Thus, the function of this organelle in neocortical neurons remains elusive.
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Affiliation(s)
- Jon I Arellano
- Department of Neurobiology, Yale University School of Medicine, New Haven, Connecticut 06510, USA.
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14
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Sattar S, Gleeson JG. The ciliopathies in neuronal development: a clinical approach to investigation of Joubert syndrome and Joubert syndrome-related disorders. Dev Med Child Neurol 2011; 53:793-798. [PMID: 21679365 PMCID: PMC3984879 DOI: 10.1111/j.1469-8749.2011.04021.x] [Citation(s) in RCA: 95] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
A group of disorders with disparate symptomatology, including congenital cerebellar ataxia, retinal blindness, liver fibrosis, polycystic kidney disease, and polydactyly, have recently been united under a single disease mechanism called 'ciliopathies'. The ciliopathies are due to defects of the cellular antenna known as the primary cilium, a microtubule-based extension of cellular membranes found in nearly all cell types. Key among these ciliopathies is Joubert syndrome, displaying ataxia, oculomotor apraxia, and mental retardation* with a pathognomonic 'molar tooth sign' on brain magnetic resonance imaging. The importance of ciliary function in neuronal development has been appreciated only in the last decade with the classification of Joubert syndrome as a ciliopathy. This, together with the identification of many of the clinical features of ciliopathies in individuals with Joubert syndrome and the localization of Joubert syndrome's causative gene products at or near the primary cilium, have defined a new class of neurological disease. Cilia are involved in diverse cellular processes including protein trafficking, photoreception, embryonic axis patterning, and cell cycle regulation. Ciliary dysfunction can affect a single tissue or manifest as multi-organ involvement. Ciliary defects have been described in retinopathies such as retinitis pigmentosa and Leber congenital amaurosis (defects in photoreceptor ciliary protein complexes), renal syndromes with nephronophthisis and cystic dysplastic kidneys, and liver conditions such as fibrosis and biliary cirrhosis. Recognizing the diverse presentations of the ciliopathies and screening strategies following diagnosis is an important part of the treatment plan of children with cilia-related disorders.
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Affiliation(s)
- Shifteh Sattar
- Department of Neurosciences and Paediatrics, University of California, San Diego, La Jolla, CA, USA
| | - Joseph G Gleeson
- Department of Neurosciences and Paediatrics, University of California, San Diego, La Jolla, CA, USA
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15
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Keppler-Noreuil KM, Blumhorst C, Sapp JC, Brinckman D, Johnston J, Nopoulos PC, Biesecker LG. Brain tissue- and region-specific abnormalities on volumetric MRI scans in 21 patients with Bardet-Biedl syndrome (BBS). BMC MEDICAL GENETICS 2011; 12:101. [PMID: 21794117 PMCID: PMC3199749 DOI: 10.1186/1471-2350-12-101] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Received: 02/11/2011] [Accepted: 07/27/2011] [Indexed: 11/10/2022]
Abstract
Background Bardet-Biedl syndrome (BBS) is a heterogeneous human disorder inherited in an autosomal recessive pattern, and characterized by the primary findings of obesity, polydactyly, hypogonadism, and learning and behavioural problems. BBS mouse models have a neuroanatomical phenotype consisting of third and lateral ventriculomegaly, thinning of the cerebral cortex, and reduction in the size of the corpus striatum and hippocampus. These abnormalities raise the question of whether humans with BBS have a characteristic morphologic brain phenotype. Further, although behavioral, developmental, neurological and motor defects have been noted in patients with BBS, to date, there are limited reports of brain findings in BBS. The present study represents the largest systematic evaluation for the presence of structural brain malformations and/or progressive changes, which may contribute to these functional problems. Methods A case-control study of 21 patients, most aged 13-35 years, except for 2 patients aged 4 and 8 years, who were diagnosed with BBS by clinical criteria and genetic analysis of known BBS genes, and were evaluated by qualitative and volumetric brain MRI scans. Healthy controls were matched 3:1 by age, sex and race. Statistical analysis was performed using SAS language with SAS STAT procedures. Results All 21 patients with BBS were found to have statistically significant region- and tissue-specific patterns of brain abnormalities. There was 1) normal intracranial volume; 2) reduced white matter in all regions of the brain, but most in the occipital region; 3) preserved gray matter volume, with increased cerebral cortex volume in only the occipital lobe; 4) reduced gray matter in the subcortical regions of the brain, including the caudate, putamen and thalamus, but not in the cerebellum; and 5) increased cerebrospinal fluid volume. Conclusions There are distinct and characteristic abnormalities in tissue- and region- specific volumes of the brain in patients with BBS, which parallel the findings, described in BBS mutant mouse models. Some of these brain abnormalities may be progressive and associated with the reported neurological and behavioral problems. Further future correlation of these MRI scan findings with detailed neurologic and neuropsychological exams together with genotype data will provide better understanding of the pathophysiology of BBS.
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Affiliation(s)
- Kim M Keppler-Noreuil
- Department of Pediatrics, Division of Medical Genetics, The University of Iowa Children's Hospital, Iowa City, IA 52242, USA.
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16
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Abstract
PURPOSE OF REVIEW Ciliopathies are genetic disorders caused by defects of primary ciliary structure and/or function and are characterized by pleiotropic clinical features. The ciliopathies include several partially overlapping syndromes such as Joubert syndrome, Bardet-Biedl syndrome and Meckel-Gruber syndrome, all of which have pronounced neurodevelopmental features. Here we focus on potential roles of cilia in central nervous system function, to explore how impairments may cause brain malformation and neurodevelopmental disease. RECENT FINDINGS Cilia have long been considered as 'sensory cellular antennae', responding as chemo-sensors, mechano-sensors and thermo-sensors, although their roles in development were not well understood until recently. The surprising finding that disparate syndromes are all due to defects of the primary cilia, along with the recent advances in genetics, has helped elucidate further roles of primary cilia beyond sensory functions. Several molecules that are associated with key signaling pathways have been discovered in primary cilia. These include sonic hedgehog, wingless, planar cell polarity and fibroblast growth factor, which are essential for many cellular processes. Additionally, mutations in 'ciliome' genes have largely shown developmental defects such as abnormal body axis and brain malformation, implying disrupted cilia-related signaling pathways. Accordingly, the emerging theme is that primary cilia may play roles as modulators of signal transduction to help shape cellular responses within the environmental context during both development and homeostasis. SUMMARY The link between cilia and signal pathways has become a framework for understanding the pathogenesis of ciliopathies. Despite recent progress in ciliary biology, fundamental questions remain about how cilia regulate neuronal function in the central nervous system. Therefore, investigation of ciliary function in the nervous system may reveal cilia-modulating mechanisms in neurodevelopmental processes, as well as suggest new treatments for disease.
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17
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D'Angelo A, Franco B. The primary cilium in different tissues-lessons from patients and animal models. Pediatr Nephrol 2011; 26:655-62. [PMID: 20890766 DOI: 10.1007/s00467-010-1650-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2010] [Revised: 07/22/2010] [Accepted: 08/11/2010] [Indexed: 11/29/2022]
Abstract
Primary cilia are specialized organelles consisting of an axoneme anchored to the plasma membrane through the basal body consisting of two centrioles. They protrude from the cell surface of almost all mammalian cells. Mutations in genes encoding for ciliary proteins cause ciliopathies, which are characterized by a wide spectrum of phenotypes, including polycystic kidney, hepatic disease, malformations in the central nervous system, skeletal defects, retinal degeneration, and obesity. Both clinical studies and animal models have revealed that during embryogenesis, primary cilium play an essential role in defining the correct patterning of the body. In this study, we focused our attention on the tissues mainly affected in ciliopathies, such as the kidney, liver, and central nervous system. Emerging studies reveal that the primary cilium may play similar roles, leading to distinct functions according to the different cell type and developmental stages. The state of the art in primary cilia studies reveals a very complex role. The aim of this review is to evaluate the recent advances in the function of primary cilia in different tissues, underlining similarities and differences.
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Affiliation(s)
- Anna D'Angelo
- Telethon Institute of Genetics and Medicine, Via Pietro Castellino, Naples, Italy
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18
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Baker K, Northam GB, Chong WK, Banks T, Beales P, Baldeweg T. Neocortical and hippocampal volume loss in a human ciliopathy: A quantitative MRI study in Bardet-Biedl syndrome. Am J Med Genet A 2010; 155A:1-8. [PMID: 21204204 DOI: 10.1002/ajmg.a.33773] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2010] [Accepted: 09/11/2010] [Indexed: 11/08/2022]
Abstract
Cilia are ubiquitous cell surface organelles with diverse roles from embryogenesis to adult life. The neurodevelopmental functions of the cilium are currently under investigation in animal systems, but relevance to human brain development remains uncertain. We present the first systematic investigation of structural neuroanatomy in a ciliopathy-Bardet-Biedl syndrome (BBS). Qualitative and quantitative aspects of brain structure were evaluated via magnetic resonance imaging in 10 patients with BBS (ages 14-28 years). In comparison to age and gender-matched healthy controls, BBS patients had significantly reduced total gray matter (GM) volume but no total white matter (WM) or cerebrospinal fluid volume changes. Voxel-based morphometric analysis indicated regional GM volume loss bilaterally in the anterior temporal lobes and in the medial orbitofrontal cortex, and WM volume loss in the right inferior longitudinal fasciculus. Region-of-interest measurements revealed reduced volume of the hippocampus. Two patients were found to have ventriculomegaly. Global GM reduction and regional volume reductions in the temporal lobe may underlie the learning disabilities and behavioral problems experienced by some patients with BBS. These findings are consistent with previous observations in mouse models of BBS, and further implicate the cilium in neurodevelopmental processes relevant to human cognitive function.
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Affiliation(s)
- Kate Baker
- UCL Institute of Child Health, London, UK.
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19
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Anastas SB, Mueller D, Semple-Rowland SL, Breunig JJ, Sarkisian MR. Failed cytokinesis of neural progenitors in citron kinase-deficient rats leads to multiciliated neurons. ACTA ACUST UNITED AC 2010; 21:338-44. [PMID: 20525772 DOI: 10.1093/cercor/bhq099] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Most, if not all, cortical neurons possess a single primary cilium; however, little is known about the mechanisms that control neuronal ciliogenesis. The Citron kinase-deficient (Citron-K(fh/fh)) rat, a model in which failed cytokinesis during development produces cortical neurons containing multiple cellular organelles, provides a unique system in which to examine the relationship between centriole inheritance and neuronal ciliogenesis. In this study, we analyzed the cerebral cortex of these animals using immunohistochemistry, serial confocal, and electron microscopy to determine if the multinucleated neurons present in the cortex of these animals also possess multiple centrioles and cilia. We found that neurons containing multiple nuclei possessed multiple centrioles and cilia whose lengths varied across cortical regions. Despite the presence of multiple cilia, we found that perinatal expression of adenylyl cyclase III, a cilia-specific marker, and somatostatin receptor 3, a receptor enriched in cilia, were preserved in developing Citron-K(fh/fh) brain. Together, these results show that multinucleated neurons arising from defective cytokinesis can extend multiple cilia.
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Affiliation(s)
- Sara B Anastas
- Department of Neuroscience, McKnight Brain Institute, University of Florida, Gainesville, FL 32610-0244, USA
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20
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Hayashi-Takagi A, Sawa A. Disturbed synaptic connectivity in schizophrenia: convergence of genetic risk factors during neurodevelopment. Brain Res Bull 2010; 83:140-6. [PMID: 20433911 DOI: 10.1016/j.brainresbull.2010.04.007] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2009] [Revised: 02/07/2010] [Accepted: 04/19/2010] [Indexed: 12/13/2022]
Abstract
The pathological mechanisms underlying schizophrenia are unclear. Although genetic susceptibility factors for schizophrenia likely influence neurodevelopmental processes, the onset of the disease is in adolescence and young adulthood. Here we review recent literatures implicating neurodevelopmental deficits in schizophrenia and discuss how genetic factors are involved in the processes toward onset of the disease. We emphasize the importance of postnatal glutamate synapse development in the pathology of the disorder. These genetic risk factors contribute to the process possibly in a synergistic manner. The notion of signal pathways involving more than one genetic factor is in accord with the multifactorial nature of schizophrenia.
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Affiliation(s)
- Akiko Hayashi-Takagi
- Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21287, United States.
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21
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Lee JH, Gleeson JG. The role of primary cilia in neuronal function. Neurobiol Dis 2010; 38:167-72. [PMID: 20097287 DOI: 10.1016/j.nbd.2009.12.022] [Citation(s) in RCA: 90] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2009] [Revised: 11/09/2009] [Accepted: 12/26/2009] [Indexed: 10/19/2022] Open
Abstract
The "ciliopathies" are a newly defined group of disorders characterized by defects in the structure or function of the cellular primary cilium. Patients with these disorders display variably expressive fibrocystic renal disease, retinal blindness, polydactyly, obesity, and brain dysgenesis as well as neurocognitive impairments. Joubert syndrome is a ciliopathy defined by cerebellar vermis hypoplasia, oculomotor apraxia, intermittent hyperventilation, and mental retardation. Recent evidence suggests important roles for the primary cilium in mediating a host of extracellular signaling events such as morphogen, mitogen, homeostatic and polarity signals. Based upon the clinical features of ciliopathies and cilia mediated signaling pathways, the data support a role for the primary cilium in modulating neurogenesis, cell polarity, axonal guidance and possibly adult neuronal function.
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Affiliation(s)
- Jeong Ho Lee
- Department of Neurosciences and Pediatrics, Howard Hughes Medical Institute, University of California, San Diego, CA 92093-0665, USA
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22
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Zaghloul NA, Katsanis N. Mechanistic insights into Bardet-Biedl syndrome, a model ciliopathy. J Clin Invest 2009; 119:428-37. [PMID: 19252258 PMCID: PMC2648685 DOI: 10.1172/jci37041] [Citation(s) in RCA: 265] [Impact Index Per Article: 17.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Bardet-Biedl syndrome (BBS) is a multisystemic disorder typified by developmental and progressive degenerative defects. A combination of genetic, in vitro, and in vivo studies have highlighted ciliary dysfunction as a primary cause of BBS pathology, which has in turn contributed to the improved understanding of the functions of the primary cilium in humans and other vertebrates. Here we discuss the evidence linking the clinical BBS phenotype to ciliary defects, highlight how the genetic and cellular characteristics of BBS overlap with and inform other ciliary disorders, and explore the possible mechanistic underpinnings of ciliary dysfunction.
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Affiliation(s)
- Norann A. Zaghloul
- McKusick-Nathans Institute of Genetic Medicine, Wilmer
Eye Institute, and Department of Molecular Biology and Genetics, Johns
Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Nicholas Katsanis
- McKusick-Nathans Institute of Genetic Medicine, Wilmer
Eye Institute, and Department of Molecular Biology and Genetics, Johns
Hopkins University School of Medicine, Baltimore, Maryland, USA
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23
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Rooryck C, Lacombe D. [Bardet-Biedl syndrome]. ANNALES D'ENDOCRINOLOGIE 2008; 69:463-71. [PMID: 19019343 DOI: 10.1016/j.ando.2008.10.001] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/18/2008] [Indexed: 10/21/2022]
Abstract
Bardet-Biedl syndrome (BBS) is a ciliopathy causing multivisceral abnormalities. Its prevalence in Europe is from 1/125,000 to 1/175,000. This disorder is defined by a combination of clinical signs: obesity, pigmentary retinopathy, post-axial polydactyly, polycystic kidneys, hypogenitalism, and learning disabilities, many of which appearing after several years of evolution. Individual clinical phenotype is highly variable. Most signs are present in a majority of patients but only pigmentary retinopathy is constant after infancy. There are many other associated minor clinical signs including diabetes, blood hypertension, congenital cardiopathy or Hirschsprung disease. This broad clinical spectrum is associated to a great genetic heterogeneity, with mainly an autosomal recessive transmission and, sometimes cases of oligogenism. To date, mutations in 12 different genes (BBS1 to BBS12) are responsible for this phenotype. These genes code for proteins involved in the development and function of primary cilia. Absent or non functional BBS proteins affect cilia in certain organs such as kidney or eye. However, some symptoms are still not clearly related to cilia dysfunction. BB syndrome has to be recognized because a molecular diagnosis is possible and will lead to familial genetic counseling and possibly prenatal diagnosis. Patients with BBS will need a multidisciplinary medical care. The renal abnormalities are the main life-threatening features because they can lead to end-stage renal failure and renal transplantation. Retinal dystrophy leading to progressive vision loss, moderate mental retardation, and obesity will affect social life of these patients.
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Affiliation(s)
- C Rooryck
- Laboratoire de Génétique Humaine, Université Victor-Segalen, Bordeaux cedex, France.
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A knockin mouse model of the Bardet-Biedl syndrome 1 M390R mutation has cilia defects, ventriculomegaly, retinopathy, and obesity. Proc Natl Acad Sci U S A 2007; 104:19422-7. [PMID: 18032602 DOI: 10.1073/pnas.0708571104] [Citation(s) in RCA: 191] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Bardet-Biedl syndrome (BBS) is a genetically heterogeneous disorder that results in retinal degeneration, obesity, cognitive impairment, polydactyly, renal abnormalities, and hypogenitalism. Of the 12 known BBS genes, BBS1 is the most commonly mutated, and a single missense mutation (M390R) accounts for approximately 80% of BBS1 cases. To gain insight into the function of BBS1, we generated a Bbs1(M390R/M390R) knockin mouse model. Mice homozygous for the M390R mutation recapitulated aspects of the human phenotype, including retinal degeneration, male infertility, and obesity. The obese mutant mice were hyperphagic and hyperleptinemic and exhibited reduced locomotor activity but no elevation in mean arterial blood pressure. Morphological evaluation of Bbs1 mutant brain neuroanatomy revealed ventriculomegaly of the lateral and third ventricles, thinning of the cerebral cortex, and reduced volume of the corpus striatum and hippocampus. Similar abnormalities were also observed in the brains of Bbs2(-/-), Bbs4(-/-), and Bbs6(-/-) mice, establishing these neuroanatomical defects as a previously undescribed BBS mouse model phenotype. Ultrastructural examination of the ependymal cell cilia that line the enlarged third ventricle of the Bbs1 mutant brains showed that, whereas the 9 + 2 arrangement of axonemal microtubules was intact, elongated cilia and cilia with abnormally swollen distal ends were present. Together with data from transmission electron microscopy analysis of photoreceptor cell connecting cilia, the Bbs1 M390R mutation does not affect axonemal structure, but it may play a role in the regulation of cilia assembly and/or function.
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