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Ma R, Chen L, Hu N, Caplan S, Hu G. Cilia and Extracellular Vesicles in Brain Development and Disease. Biol Psychiatry 2024; 95:1020-1029. [PMID: 37956781 PMCID: PMC11087377 DOI: 10.1016/j.biopsych.2023.11.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 10/21/2023] [Accepted: 11/05/2023] [Indexed: 11/15/2023]
Abstract
Primary and motile cilia are thin, hair-like cellular projections from the cell surface involved in movement, sensing, and communication between cells. Extracellular vesicles (EVs) are small membrane-bound vesicles secreted by cells and contain various proteins, lipids, and nucleic acids that are delivered to and influence the behavior of other cells. Both cilia and EVs are essential for the normal functioning of brain cells, and their malfunction can lead to several neurological diseases. Cilia and EVs can interact with each other in several ways, and this interplay plays a crucial role in facilitating various biological processes, including cell-to-cell communication, tissue homeostasis, and pathogen defense. Cilia and EV crosstalk in the brain is an emerging area of research. Herein, we summarize the detailed molecular mechanisms of cilia and EV interplay and address the ciliary molecules that are involved in signaling and cellular dysfunction in brain development and diseases. Finally, we discuss the potential clinical use of cilia and EVs in brain diseases.
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Affiliation(s)
- Rong Ma
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska; Department of Pharmacology, School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, Hubei, China
| | - Liang Chen
- Department of Computer Science, College of Engineering, Shantou University, Shantou, Guangdong, China
| | - Ningyun Hu
- Millard West High School, Omaha, Nebraska
| | - Steve Caplan
- Department of Biochemistry & Molecular Biology, University of Nebraska Medical Center, Omaha, Nebraska; Fred and Pamela Buffett Cancer Center, University of Nebraska Medical Center, Omaha, Nebraska.
| | - Guoku Hu
- Department of Pharmacology and Experimental Neuroscience, University of Nebraska Medical Center, Omaha, Nebraska.
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2
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Ali S, Abrar M, Hussain I, Batool F, Raza RZ, Khatoon H, Zoia M, Visel A, Shubin NH, Osterwalder M, Abbasi AA. Identification of ancestral gnathostome Gli3 enhancers with activity in mammals. Dev Growth Differ 2024; 66:75-88. [PMID: 37925606 PMCID: PMC10841732 DOI: 10.1111/dgd.12901] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2023] [Revised: 09/01/2023] [Accepted: 10/23/2023] [Indexed: 11/06/2023]
Abstract
Abnormal expression of the transcriptional regulator and hedgehog (Hh) signaling pathway effector Gli3 is known to trigger congenital disease, most frequently affecting the central nervous system (CNS) and the limbs. Accurate delineation of the genomic cis-regulatory landscape controlling Gli3 transcription during embryonic development is critical for the interpretation of noncoding variants associated with congenital defects. Here, we employed a comparative genomic analysis on fish species with a slow rate of molecular evolution to identify seven previously unknown conserved noncoding elements (CNEs) in Gli3 intronic intervals (CNE15-21). Transgenic assays in zebrafish revealed that most of these elements drive activities in Gli3 expressing tissues, predominantly the fins, CNS, and the heart. Intersection of these CNEs with human disease associated SNPs identified CNE15 as a putative mammalian craniofacial enhancer, with conserved activity in vertebrates and potentially affected by mutation associated with human craniofacial morphology. Finally, comparative functional dissection of an appendage-specific CNE conserved in slowly evolving fish (elephant shark), but not in teleost (CNE14/hs1586) indicates co-option of limb specificity from other tissues prior to the divergence of amniotes and lobe-finned fish. These results uncover a novel subset of intronic Gli3 enhancers that arose in the common ancestor of gnathostomes and whose sequence components were likely gradually modified in other species during the process of evolutionary diversification.
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Affiliation(s)
- Shahid Ali
- National Center for Bioinformatics, Program of Comparative and Evolutionary Genomics, Faculty of Biological Sciences, Quaid-i-Azam University, 45320, Islamabad Pakistan
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL 60637, USA
| | - Muhammad Abrar
- National Center for Bioinformatics, Program of Comparative and Evolutionary Genomics, Faculty of Biological Sciences, Quaid-i-Azam University, 45320, Islamabad Pakistan
| | - Irfan Hussain
- National Center for Bioinformatics, Program of Comparative and Evolutionary Genomics, Faculty of Biological Sciences, Quaid-i-Azam University, 45320, Islamabad Pakistan
| | - Fatima Batool
- National Center for Bioinformatics, Program of Comparative and Evolutionary Genomics, Faculty of Biological Sciences, Quaid-i-Azam University, 45320, Islamabad Pakistan
| | - Rabail Zehra Raza
- Department of Biological Sciences, Faculty of Multidisciplinary Studies, National University of Medical Sciences Rawalpindi, Pakistan
| | - Hizran Khatoon
- National Center for Bioinformatics, Program of Comparative and Evolutionary Genomics, Faculty of Biological Sciences, Quaid-i-Azam University, 45320, Islamabad Pakistan
| | - Matteo Zoia
- Department for Biomedical Research (DBMR), University of Bern, Bern, Switzerland
| | - Axel Visel
- Environmental Genomics and System Biology Division, Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720, USA
- U.S. Department of Energy Joint Genome Institute, 1 Cyclotron Road, Berkeley, CA 94720, USA
- School of Natural Sciences, University of California, Merced, Merced, CA 95343, USA
| | - Neil H. Shubin
- Department of Organismal Biology and Anatomy, The University of Chicago, Chicago, IL 60637, USA
| | - Marco Osterwalder
- Department for Biomedical Research (DBMR), University of Bern, Bern, Switzerland
- Department of Cardiology, Bern University Hospital, Bern, Switzerland
| | - Amir Ali Abbasi
- National Center for Bioinformatics, Program of Comparative and Evolutionary Genomics, Faculty of Biological Sciences, Quaid-i-Azam University, 45320, Islamabad Pakistan
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3
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Yang KY, Zhao S, Feng H, Shen J, Chen Y, Wang ST, Wang SJ, Zhang YX, Wang Y, Guo C, Liu H, Tang TS. Ca 2+ homeostasis maintained by TMCO1 underlies corpus callosum development via ERK signaling. Cell Death Dis 2022; 13:674. [PMID: 35927240 PMCID: PMC9352667 DOI: 10.1038/s41419-022-05131-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Revised: 07/22/2022] [Accepted: 07/25/2022] [Indexed: 01/21/2023]
Abstract
Transmembrane of coiled-coil domains 1 (TMCO1) plays an important role in maintaining homeostasis of calcium (Ca2+) stores in the endoplasmic reticulum (ER). TMCO1-defect syndrome shares multiple features with human cerebro-facio-thoracic (CFT) dysplasia, including abnormal corpus callosum (CC). Here, we report that TMCO1 is required for the normal development of CC through sustaining Ca2+ homeostasis. Tmco1-/- mice exhibit severe agenesis of CC with stalled white matter fiber bundles failing to pass across the midline. Mechanistically, the excessive Ca2+ signals caused by TMCO1 deficiency result in upregulation of FGFs and over-activation of ERK, leading to an excess of glial cell migration and overpopulated midline glia cells in the indusium griseum which secretes Slit2 to repulse extension of the neural fiber bundles before crossing the midline. Supportingly, using the clinical MEK inhibitors to attenuate the over-activated FGF/ERK signaling can significantly improve the CC formation in Tmco1-/- brains. Our findings not only unravel the underlying mechanism of abnormal CC in TMCO1 defect syndrome, but also offer an attractive prevention strategy to relieve the related agenesis of CC in patients.
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Affiliation(s)
- Ke-Yan Yang
- grid.410726.60000 0004 1797 8419State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101 China
| | - Song Zhao
- grid.410726.60000 0004 1797 8419State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101 China
| | - Haiping Feng
- grid.410726.60000 0004 1797 8419State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101 China
| | - Jiaqi Shen
- grid.410726.60000 0004 1797 8419State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101 China
| | - Yuwei Chen
- grid.410726.60000 0004 1797 8419Beijing Institute of Genomics, University of Chinese Academy of Sciences, Chinese Academy of Sciences/China National Center for Bioinformation, Beijing, 100101 China
| | - Si-Tong Wang
- grid.410726.60000 0004 1797 8419State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101 China
| | - Si-Jia Wang
- grid.410726.60000 0004 1797 8419State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101 China
| | - Yu-Xin Zhang
- grid.410726.60000 0004 1797 8419State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101 China
| | - Yun Wang
- grid.410726.60000 0004 1797 8419State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101 China
| | - Caixia Guo
- grid.410726.60000 0004 1797 8419Beijing Institute of Genomics, University of Chinese Academy of Sciences, Chinese Academy of Sciences/China National Center for Bioinformation, Beijing, 100101 China
| | - Hongmei Liu
- grid.410726.60000 0004 1797 8419State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101 China ,grid.9227.e0000000119573309Institute for Stem cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101 China ,grid.512959.3Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101 China
| | - Tie-Shan Tang
- grid.410726.60000 0004 1797 8419State Key Laboratory of Membrane Biology, Institute of Zoology, University of Chinese Academy of Sciences, Chinese Academy of Sciences, Beijing, 100101 China ,grid.9227.e0000000119573309Institute for Stem cell and Regeneration, Chinese Academy of Sciences, Beijing, 100101 China ,grid.512959.3Beijing Institute for Stem Cell and Regenerative Medicine, Beijing, 100101 China
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Hasenpusch-Theil K, Theil T. The Multifaceted Roles of Primary Cilia in the Development of the Cerebral Cortex. Front Cell Dev Biol 2021; 9:630161. [PMID: 33604340 PMCID: PMC7884624 DOI: 10.3389/fcell.2021.630161] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2020] [Accepted: 01/11/2021] [Indexed: 12/12/2022] Open
Abstract
The primary cilium, a microtubule based organelle protruding from the cell surface and acting as an antenna in multiple signaling pathways, takes center stage in the formation of the cerebral cortex, the part of the brain that performs highly complex neural tasks and confers humans with their unique cognitive capabilities. These activities require dozens of different types of neurons that are interconnected in complex ways. Due to this complexity, corticogenesis has been regarded as one of the most complex developmental processes and cortical malformations underlie a number of neurodevelopmental disorders such as intellectual disability, autism spectrum disorders, and epilepsy. Cortical development involves several steps controlled by cell–cell signaling. In fact, recent findings have implicated cilia in diverse processes such as neurogenesis, neuronal migration, axon pathfinding, and circuit formation in the developing cortex. Here, we will review recent advances on the multiple roles of cilia during cortex formation and will discuss the implications for a better understanding of the disease mechanisms underlying neurodevelopmental disorders.
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Affiliation(s)
- Kerstin Hasenpusch-Theil
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, United Kingdom
| | - Thomas Theil
- Centre for Discovery Brain Sciences, University of Edinburgh, Edinburgh, United Kingdom.,Simons Initiative for the Developing Brain, University of Edinburgh, Edinburgh, United Kingdom
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5
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Andreu-Cervera A, Catala M, Schneider-Maunoury S. Cilia, ciliopathies and hedgehog-related forebrain developmental disorders. Neurobiol Dis 2020; 150:105236. [PMID: 33383187 DOI: 10.1016/j.nbd.2020.105236] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2020] [Revised: 12/18/2020] [Accepted: 12/26/2020] [Indexed: 02/07/2023] Open
Abstract
Development of the forebrain critically depends on the Sonic Hedgehog (Shh) signaling pathway, as illustrated in humans by the frequent perturbation of this pathway in holoprosencephaly, a condition defined as a defect in the formation of midline structures of the forebrain and face. The Shh pathway requires functional primary cilia, microtubule-based organelles present on virtually every cell and acting as cellular antennae to receive and transduce diverse chemical, mechanical or light signals. The dysfunction of cilia in humans leads to inherited diseases called ciliopathies, which often affect many organs and show diverse manifestations including forebrain malformations for the most severe forms. The purpose of this review is to provide the reader with a framework to understand the developmental origin of the forebrain defects observed in severe ciliopathies with respect to perturbations of the Shh pathway. We propose that many of these defects can be interpreted as an imbalance in the ratio of activator to repressor forms of the Gli transcription factors, which are effectors of the Shh pathway. We also discuss the complexity of ciliopathies and their relationships with forebrain disorders such as holoprosencephaly or malformations of cortical development, and emphasize the need for a closer examination of forebrain defects in ciliopathies, not only through the lens of animal models but also taking advantage of the increasing potential of the research on human tissues and organoids.
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Affiliation(s)
- Abraham Andreu-Cervera
- Sorbonne Université, Centre National de la Recherche Scientifique (CNRS) UMR7622, Institut national pour la Santé et la Recherche Médicale (Inserm) U1156, Institut de Biologie Paris Seine - Laboratoire de Biologie du Développement (IBPS-LBD), 9 Quai Saint-Bernard, 75005 Paris, France; Instituto de Neurociencias, Universidad Miguel Hernández - CSIC, Campus de San Juan; Avda. Ramón y Cajal s/n, 03550 Alicante, Spain
| | - Martin Catala
- Sorbonne Université, Centre National de la Recherche Scientifique (CNRS) UMR7622, Institut national pour la Santé et la Recherche Médicale (Inserm) U1156, Institut de Biologie Paris Seine - Laboratoire de Biologie du Développement (IBPS-LBD), 9 Quai Saint-Bernard, 75005 Paris, France.
| | - Sylvie Schneider-Maunoury
- Sorbonne Université, Centre National de la Recherche Scientifique (CNRS) UMR7622, Institut national pour la Santé et la Recherche Médicale (Inserm) U1156, Institut de Biologie Paris Seine - Laboratoire de Biologie du Développement (IBPS-LBD), 9 Quai Saint-Bernard, 75005 Paris, France.
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6
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Matissek SJ, Elsawa SF. GLI3: a mediator of genetic diseases, development and cancer. Cell Commun Signal 2020; 18:54. [PMID: 32245491 PMCID: PMC7119169 DOI: 10.1186/s12964-020-00540-x] [Citation(s) in RCA: 56] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Accepted: 02/27/2020] [Indexed: 02/07/2023] Open
Abstract
The transcription factor GLI3 is a member of the Hedgehog (Hh/HH) signaling pathway that can exist as a full length (Gli3-FL/GLI3-FL) or repressor (Gli3-R/GLI3-R) form. In response to HH activation, GLI3-FL regulates HH genes by targeting the GLI1 promoter. In the absence of HH signaling, GLI3 is phosphorylated leading to its partial degradation and the generation of GLI3-R which represses HH functions. GLI3 is also involved in tissue development, immune cell development and cancer. The absence of Gli3 in mice impaired brain and lung development and GLI3 mutations in humans are the cause of Greig cephalopolysyndactyly (GCPS) and Pallister Hall syndromes (PHS). In the immune system GLI3 regulates B, T and NK-cells and may be involved in LPS-TLR4 signaling. In addition, GLI3 was found to be upregulated in multiple cancers and was found to positively regulate cancerous behavior such as anchorage-independent growth, angiogenesis, proliferation and migration with the exception in acute myeloid leukemia (AML) and medulloblastoma where GLI plays an anti-cancerous role. Finally, GLI3 is a target of microRNA. Here, we will review the biological significance of GLI3 and discuss gaps in our understanding of this molecule. Video Abstract.
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Affiliation(s)
- Stephan J. Matissek
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, 46 College Rd Rudman 291, Durham, NH 03824 USA
| | - Sherine F. Elsawa
- Department of Molecular, Cellular and Biomedical Sciences, University of New Hampshire, 46 College Rd Rudman 291, Durham, NH 03824 USA
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7
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Putoux A, Baas D, Paschaki M, Morlé L, Maire C, Attié-Bitach T, Thomas S, Durand B. Altered GLI3 and FGF8 signaling underlies acrocallosal syndrome phenotypes in Kif7 depleted mice. Hum Mol Genet 2020; 28:877-887. [PMID: 30445565 DOI: 10.1093/hmg/ddy392] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2018] [Revised: 10/31/2018] [Accepted: 11/08/2018] [Indexed: 11/14/2022] Open
Abstract
Acrocallosal syndrome (ACLS) is a rare genetic disorder characterized by agenesis or hypoplasia of corpus callosum (CC), polydactyly, craniofacial dysmorphism and severe intellectual deficiency. We previously identified KIF7, a key ciliary component of the Sonic hedgehog (SHH) pathway, as being a causative gene for this syndrome, thus including ACLS in the group of ciliopathies. In both humans and mice, KIF7 depletion leads to abnormal GLI3 processing and over-activation of SHH target genes. To understand the pathological mechanisms involved in CC defects in this syndrome, we took advantage of a previously described Kif7-/- mouse model to demonstrate that in addition to polydactyly and neural tube closure defects, these mice present CC agenesis with characteristic Probst bundles, thus recapitulating major ACLS features. We show that CC agenesis in these mice is associated with specific patterning defects of the cortical septum boundary leading to altered distribution of guidepost cells required to guide the callosal axons through the midline. Furthermore, by crossing Kif7-/- mice with Gli3Δ699 mice exclusively producing the repressive isoform of GLI3 (GLI3R), we demonstrate that decreased GLI3R signaling is fully responsible for the ACLS features in these mice, as all phenotypes are rescued by increasing GLI3R activity. Moreover, we show that increased FGF8 signaling is responsible in part for CC defects associated to KIF7 depletion, as modulating FGF8 signaling rescued CC formation anteriorly in Kif7-/- mice. Taken together our data demonstrate that ACLS features rely on defective GLI3R and FGF8 signaling.
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Affiliation(s)
- Audrey Putoux
- Centre de Recherche en Neurosciences de Lyon, Équipe GENDEV, INSERM U1028, CNRS UMR 5292, Université Claude Bernard Lyon 1, Lyon, France.,Service de Génétique et Centre de Référence des Anomalies du Développement de la Région Auvergne-Rhône-Alpes, CHU de Lyon, France
| | - Dominique Baas
- Institut NeuroMyoGène, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U-1217, Lyon, France
| | - Marie Paschaki
- Institut NeuroMyoGène, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U-1217, Lyon, France
| | - Laurette Morlé
- Institut NeuroMyoGène, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U-1217, Lyon, France
| | - Charline Maire
- Institut NeuroMyoGène, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U-1217, Lyon, France
| | - Tania Attié-Bitach
- Laboratory of Embryology and Genetics of Congenital Malformations, INSERM UMR1163, Sorbonne Paris Cité University, Imagine Institute, Paris, France.,Department of Histology-Embryology and Cytogenetics, Necker Hospital, AP-HP, Paris, France
| | - Sophie Thomas
- Laboratory of Embryology and Genetics of Congenital Malformations, INSERM UMR1163, Sorbonne Paris Cité University, Imagine Institute, Paris, France
| | - Bénédicte Durand
- Institut NeuroMyoGène, Université Claude Bernard Lyon 1, CNRS UMR 5310, INSERM U-1217, Lyon, France
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Ma M, Legué E, Tian X, Somlo S, Liem KF. Cell-Autonomous Hedgehog Signaling Is Not Required for Cyst Formation in Autosomal Dominant Polycystic Kidney Disease. J Am Soc Nephrol 2019; 30:2103-2111. [PMID: 31451534 DOI: 10.1681/asn.2018121274] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 07/15/2019] [Indexed: 01/20/2023] Open
Abstract
BACKGROUND PKD1 or PKD2, the two main causal genes for autosomal dominant polycystic kidney disease (ADPKD), encode the multipass transmembrane proteins polycystin-1 (PC1) and polycystin-2 (PC2), respectively. Polycystins localize to the primary cilium, an organelle essential for cell signaling, including signal transduction of the Hedgehog pathway. Mutations in ciliary genes that build and maintain the cilium also cause renal cystic disease through unknown pathways. Although recent studies have found alterations in Hedgehog signaling in ADPKD-related models and tissues, the relationship between Hedgehog and polycystic kidney disease is not known. METHODS To examine the potential role of cell-autonomous Hedgehog signaling in regulating kidney cyst formation in vivo in both early- and adult-onset mouse models of ADPKD, we used conditional inactivation of Pkd1 combined with conditional modulation of Hedgehog signaling components in renal epithelial cells, where mutations in Pkd1 initiate cyst formation. After increasing or decreasing levels of Hedgehog signaling in cells that underwent inactivation of Pkd1, we evaluated the effects of these genetic manipulations on quantitative parameters of polycystic kidney disease severity. RESULTS We found that in Pkd1 conditional mutant mouse kidneys, neither downregulation nor activation of the Hedgehog pathway in epithelial cells along the nephron significantly influenced the severity of the polycystic kidney phenotype in mouse models of developmental or adult-onset of ADPKD. CONCLUSIONS These data suggest that loss of Pkd1 function results in kidney cysts through pathways that are not affected by the activity of the Hedgehog pathway.
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Affiliation(s)
- Ming Ma
- Departments of Internal Medicine
| | - Emilie Legué
- Pediatrics, and.,Vertebrate Developmental Biology Program, Yale University, New Haven, Connecticut
| | - Xin Tian
- Departments of Internal Medicine
| | | | - Karel F Liem
- Pediatrics, and .,Vertebrate Developmental Biology Program, Yale University, New Haven, Connecticut
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Abstract
The corpus callosum is the largest of the 3 telencephalic commissures in eutherian (placental) mammals. Although the anterior commissure, and the hippocampal commissure before being pushed dorsally by the expanding frontal lobes, cross through the lamina reuniens (upper part of the lamina terminalis), the callosal fibers need a transient interhemispheric cellular bridge to cross. This review describes the molecular pathways that initiate the specification of the cells comprising this bridge, the specification of the callosal neurons, and the repulsive and attractive guidance molecules that convey the callosal axons toward, across, and away from the midline to connect with their targets.
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10
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Hasenpusch-Theil K, West S, Kelman A, Kozic Z, Horrocks S, McMahon AP, Price DJ, Mason JO, Theil T. Gli3 controls the onset of cortical neurogenesis by regulating the radial glial cell cycle through Cdk6 expression. Development 2018; 145:dev.163147. [PMID: 30093555 PMCID: PMC6141774 DOI: 10.1242/dev.163147] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2018] [Accepted: 07/13/2018] [Indexed: 01/03/2023]
Abstract
The cerebral cortex contains an enormous number of neurons, allowing it to perform highly complex neural tasks. Understanding how these neurons develop at the correct time and place and in accurate numbers constitutes a major challenge. Here, we demonstrate a novel role for Gli3, a key regulator of cortical development, in cortical neurogenesis. We show that the onset of neuron formation is delayed in Gli3 conditional mouse mutants. Gene expression profiling and cell cycle measurements indicate that shortening of the G1 and S phases in radial glial cells precedes this delay. Reduced G1 length correlates with an upregulation of the cyclin-dependent kinase gene Cdk6, which is directly regulated by Gli3. Moreover, pharmacological interference with Cdk6 function rescues the delayed neurogenesis in Gli3 mutant embryos. Overall, our data indicate that Gli3 controls the onset of cortical neurogenesis by determining the levels of Cdk6 expression, thereby regulating neuronal output and cortical size.
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Affiliation(s)
- Kerstin Hasenpusch-Theil
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Stephen West
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Alexandra Kelman
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Zrinko Kozic
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Sophie Horrocks
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Andrew P McMahon
- Department of Stem Cell Biology and Regenerative Medicine, Eli and Edythe Broad-CIRM Center for Regenerative Medicine and Stem Cell Research, W.M. Keck School of Medicine, University of Southern California, Los Angeles, CA 90033, USA
| | - David J Price
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - John O Mason
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Thomas Theil
- Centre for Discovery Brain Sciences, Hugh Robson Building, University of Edinburgh, Edinburgh EH8 9XD, UK
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11
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Hasenpusch-Theil K, Watson JA, Theil T. Direct Interactions Between Gli3, Wnt8b, and Fgfs Underlie Patterning of the Dorsal Telencephalon. Cereb Cortex 2018; 27:1137-1148. [PMID: 26656997 DOI: 10.1093/cercor/bhv291] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
A key step in the development of the cerebral cortex is a patterning process, which subdivides the telencephalon into several molecularly distinct domains and is critical for cortical arealization. This process is dependent on a complex network of interactions between signaling molecules of the Fgf and Wnt gene families and the Gli3 transcription factor gene, but a better knowledge of the molecular basis of the interplay between these factors is required to gain a deeper understanding of the genetic circuitry underlying telencephalic patterning. Using DNA-binding and reporter gene assays, we here investigate the possibility that Gli3 and these signaling molecules interact by directly regulating each other's expression. We show that Fgf signaling is required for Wnt8b enhancer activity in the cortical hem, whereas Wnt/β-catenin signaling represses Fgf17 forebrain enhancer activity. In contrast, Fgf and Wnt/β-catenin signaling cooperate to regulate Gli3 expression. Taken together, these findings indicate that mutual interactions between Gli3, Wnt8b, and Fgf17 are crucial elements of the balance between these factors thereby conferring robustness to the patterning process. Hence, our study provides a framework for understanding the genetic circuitry underlying telencephalic patterning and how defects in this process can affect the formation of cortical areas.
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Affiliation(s)
- Kerstin Hasenpusch-Theil
- Centre for Integrative Physiology, Hugh Robson Building, University of Edinburgh, EdinburghEH8 9XD, UK
| | - Julia A Watson
- Centre for Integrative Physiology, Hugh Robson Building, University of Edinburgh, EdinburghEH8 9XD, UK
| | - Thomas Theil
- Centre for Integrative Physiology, Hugh Robson Building, University of Edinburgh, EdinburghEH8 9XD, UK
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12
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Deters KD, Nho K, Risacher SL, Kim S, Ramanan VK, Crane PK, Apostolova LG, Saykin AJ. Genome-wide association study of language performance in Alzheimer's disease. BRAIN AND LANGUAGE 2017; 172:22-29. [PMID: 28577822 PMCID: PMC5583024 DOI: 10.1016/j.bandl.2017.04.008] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2015] [Revised: 04/25/2017] [Accepted: 04/27/2017] [Indexed: 05/04/2023]
Abstract
Language impairment is common in prodromal stages of Alzheimer's disease (AD) and progresses over time. However, the genetic architecture underlying language performance is poorly understood. To identify novel genetic variants associated with language performance, we analyzed brain MRI and performed a genome-wide association study (GWAS) using a composite measure of language performance from the Alzheimer's Disease Neuroimaging Initiative (ADNI; n=1560). The language composite score was associated with brain atrophy on MRI in language and semantic areas. GWAS identified GLI3 (GLI family zinc finger 3) as significantly associated with language performance (p<5×10-8). Enrichment of GWAS association was identified in pathways related to nervous system development and glutamate receptor function and trafficking. Our results, which warrant further investigation in independent and larger cohorts, implicate GLI3, a developmental transcription factor involved in patterning brain structures, as a putative gene associated with language dysfunction in AD.
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Affiliation(s)
- Kacie D Deters
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA; Program in Medical Neuroscience, Paul and Carole Stark Neurosciences Research Institute, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Kwangsik Nho
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Shannon L Risacher
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Sungeun Kim
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Vijay K Ramanan
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Paul K Crane
- Department of Medicine, University of Washington, Seattle, WA, USA
| | - Liana G Apostolova
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Medicine, University of Washington, Seattle, WA, USA; Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA
| | - Andrew J Saykin
- Center for Neuroimaging, Department of Radiology and Imaging Sciences, Indiana University School of Medicine, Indianapolis, IN, USA; Indiana Alzheimer Disease Center, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Medicine, University of Washington, Seattle, WA, USA; Department of Neurology, Indiana University School of Medicine, Indianapolis, IN, USA; Department of Medical and Molecular Genetics, Indiana University School of Medicine, Indianapolis, IN, USA.
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13
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Stewart CE, Corella KM, Samberg BD, Jones PT, Linscott ML, Chung WCJ. Perinatal midline astrocyte development is impaired in fibroblast growth factor 8 hypomorphic mice. Brain Res 2016; 1646:287-296. [PMID: 27291295 DOI: 10.1016/j.brainres.2016.06.015] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2015] [Revised: 05/27/2016] [Accepted: 06/09/2016] [Indexed: 12/31/2022]
Abstract
Our previous studies showed that Fgf8 mutations can cause Kallmann syndrome (KS), a form of congenital hypogonadotropic hypogonadism, in which patients do not undergo puberty and are infertile. Interestingly, some KS patients also have agenesis of the corpus callosum (ACC) suggesting that KS pathology is not limited to reproductive function. Here, we asked whether FGF8 dysfunction is the underlying cause of ACC in some KS patients. Indeed, early studies in transgenic mice with Fgf8 mutations reported the presence of failed or incomplete corpus callosum formation. Additional studies in transgenic mice showed that FGF8 function most likely prevents the prenatal elimination of glial fibrillary acidic protein (GFAP)-immunoreactive (IR) glial cells in the indusium griseum (IG) and midline zipper (MZ), two anterior-dorsal midline regions required for corpus callosum formation (i.e., between embryonic days (E) 15.5-18.5). Here, we tested the hypothesis that FGF8 function is critical for the survival of the GFAP-IR midline glial cells. First, we measured the incidence of apoptosis in the anterior-dorsal midline region in Fgf8 hypomorphic mice during embryonic corpus callosum formation. Second, we quantified the GFAP expression in the anterior-dorsal midbrain region during pre- and postnatal development, in order to study: 1) how Fgf8 hypomorphy disrupts prenatal GFAP-IR midline glial cell development, and 2) whether Fgf8 hypomorphy continues to disrupt postnatal GFAP-IR midline glial cell development. Our results indicate that perinatal FGF8 signaling is important for the timing of the onset of anterior-dorsal Gfap expression in midline glial cells suggesting that FGF8 function regulates midline GFAP-IR glial cell development, which when disrupted by Fgf8 deficiency prevents the formation of the corpus callosum. These studies provide an experimentally-based mechanistic explanation as to why corpus callosum formation may fail in KS patients with deficits in FGF signaling.
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Affiliation(s)
- Courtney E Stewart
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Kristina M Corella
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA
| | - Brittany D Samberg
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Paula T Jones
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Megan L Linscott
- Department of Biological Sciences, Kent State University, Kent, OH 44242, USA
| | - Wilson C J Chung
- School of Biomedical Sciences, Kent State University, Kent, OH 44242, USA; Department of Biological Sciences, Kent State University, Kent, OH 44242, USA.
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14
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Amaniti EM, Kelman A, Mason JO, Theil T. Cerebral Cortex Expression of Gli3 Is Required for Normal Development of the Lateral Olfactory Tract. PLoS One 2015; 10:e0141525. [PMID: 26509897 PMCID: PMC4624982 DOI: 10.1371/journal.pone.0141525] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2014] [Accepted: 10/09/2015] [Indexed: 02/03/2023] Open
Abstract
Formation of the lateral olfactory tract (LOT) and innervation of the piriform cortex represent fundamental steps to allow the transmission of olfactory information to the cerebral cortex. Several transcription factors, including the zinc finger transcription factor Gli3, influence LOT formation by controlling the development of mitral cells from which LOT axons emanate and/or by specifying the environment through which these axons navigate. Gli3 null and hypomorphic mutants display severe defects throughout the territory covered by the developing lateral olfactory tract, making it difficult to identify specific roles for Gli3 in its development. Here, we used Emx1Cre;Gli3fl/fl conditional mutants to investigate LOT formation and colonization of the olfactory cortex in embryos in which loss of Gli3 function is restricted to the dorsal telencephalon. These mutants form an olfactory bulb like structure which does not protrude from the telencephalic surface. Nevertheless, mitral cells are formed and their axons enter the piriform cortex though the LOT is shifted medially. Mitral axons also innervate a larger target area consistent with an enlargement of the piriform cortex and form aberrant projections into the deeper layers of the piriform cortex. No obvious differences were found in the expression patterns of key guidance cues. However, we found that an expansion of the piriform cortex temporally coincides with the arrival of LOT axons, suggesting that Gli3 affects LOT positioning and target area innervation through controlling the development of the piriform cortex.
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Affiliation(s)
- Eleni-Maria Amaniti
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
| | - Alexandra Kelman
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
| | - John O. Mason
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
| | - Thomas Theil
- Centre for Integrative Physiology, University of Edinburgh, Hugh Robson Building, George Square, Edinburgh, EH8 9XD, United Kingdom
- * E-mail:
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15
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Laclef C, Anselme I, Besse L, Catala M, Palmyre A, Baas D, Paschaki M, Pedraza M, Métin C, Durand B, Schneider-Maunoury S. The role of primary cilia in corpus callosum formation is mediated by production of the Gli3 repressor. Hum Mol Genet 2015; 24:4997-5014. [PMID: 26071364 DOI: 10.1093/hmg/ddv221] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/23/2015] [Accepted: 06/09/2015] [Indexed: 12/13/2022] Open
Abstract
Agenesis of the corpus callosum (AgCC) is a frequent brain disorder found in over 80 human congenital syndromes including ciliopathies. Here, we report a severe AgCC in Ftm/Rpgrip1l knockout mouse, which provides a valuable model for Meckel-Grüber syndrome. Rpgrip1l encodes a protein of the ciliary transition zone, which is essential for ciliogenesis in several cell types in mouse including neuroepithelial cells in the developing forebrain. We show that AgCC in Rpgrip1l(-/-) mouse is associated with a disturbed location of guidepost cells in the dorsomedial telencephalon. This mislocalization results from early patterning defects and abnormal cortico-septal boundary (CSB) formation in the medial telencephalon. We demonstrate that all these defects primarily result from altered GLI3 processing. Indeed, AgCC, together with patterning defects and mispositioning of guidepost cells, is rescued by overexpressing in Rpgrip1l(-/-) embryos, the short repressor form of the GLI3 transcription factor (GLI3R), provided by the Gli3(Δ699) allele. Furthermore, Gli3(Δ699) also rescues AgCC in Rfx3(-/-) embryos deficient for the ciliogenic RFX3 transcription factor that regulates the expression of several ciliary genes. These data demonstrate that GLI3 processing is a major outcome of primary cilia function in dorsal telencephalon morphogenesis. Rescuing CC formation in two independent ciliary mutants by GLI3(Δ699) highlights the crucial role of primary cilia in maintaining the proper level of GLI3R required for morphogenesis of the CC.
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Affiliation(s)
- Christine Laclef
- Sorbonne Universités, UPMC Univ Paris 06, UMR7622, CNRS, Institut de Biologie Paris Seine (IBPS)-Developmental Biology Laboratory, UMR7622, INSERM, ERL1156 and
| | - Isabelle Anselme
- Sorbonne Universités, UPMC Univ Paris 06, UMR7622, CNRS, Institut de Biologie Paris Seine (IBPS)-Developmental Biology Laboratory, UMR7622, INSERM, ERL1156 and
| | - Laurianne Besse
- Sorbonne Universités, UPMC Univ Paris 06, UMR7622, CNRS, Institut de Biologie Paris Seine (IBPS)-Developmental Biology Laboratory, UMR7622, INSERM, ERL1156 and
| | - Martin Catala
- Sorbonne Universités, UPMC Univ Paris 06, UMR7622, CNRS, Institut de Biologie Paris Seine (IBPS)-Developmental Biology Laboratory, UMR7622, INSERM, ERL1156 and Fédération de Neurologie, Groupe hospitalier Pitié-Salpêtrière-APHP, F-75013 Paris, France
| | - Aurélien Palmyre
- Sorbonne Universités, UPMC Univ Paris 06, UMR7622, CNRS, Institut de Biologie Paris Seine (IBPS)-Developmental Biology Laboratory, UMR7622, INSERM, ERL1156 and
| | - Dominique Baas
- Université Claude Bernard Lyon 1 and CNRS, CGPhiMC-UMR5534, F-69622 Villeurbanne, France and
| | - Marie Paschaki
- Université Claude Bernard Lyon 1 and CNRS, CGPhiMC-UMR5534, F-69622 Villeurbanne, France and
| | - Maria Pedraza
- Institut du Fer à Moulin, INSERM S839, F-75005 Paris, France, Sorbonne Université, UPMC Univ Paris 06, S839, Paris, France
| | - Christine Métin
- Institut du Fer à Moulin, INSERM S839, F-75005 Paris, France, Sorbonne Université, UPMC Univ Paris 06, S839, Paris, France
| | - Bénédicte Durand
- Université Claude Bernard Lyon 1 and CNRS, CGPhiMC-UMR5534, F-69622 Villeurbanne, France and
| | - Sylvie Schneider-Maunoury
- Sorbonne Universités, UPMC Univ Paris 06, UMR7622, CNRS, Institut de Biologie Paris Seine (IBPS)-Developmental Biology Laboratory, UMR7622, INSERM, ERL1156 and
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Lavado A, Ware M, Paré J, Cao X. The tumor suppressor Nf2 regulates corpus callosum development by inhibiting the transcriptional coactivator Yap. Development 2014; 141:4182-93. [PMID: 25336744 DOI: 10.1242/dev.111260] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
The corpus callosum connects cerebral hemispheres and is the largest axon tract in the mammalian brain. Callosal malformations are among the most common congenital brain anomalies and are associated with a wide range of neuropsychological deficits. Crossing of the midline by callosal axons relies on a proper midline environment that harbors guidepost cells emitting guidance cues to instruct callosal axon navigation. Little is known about what controls the formation of the midline environment. We find that two components of the Hippo pathway, the tumor suppressor Nf2 (Merlin) and the transcriptional coactivator Yap (Yap1), regulate guidepost development and expression of the guidance cue Slit2 in mouse. During normal brain development, Nf2 suppresses Yap activity in neural progenitor cells to promote guidepost cell differentiation and prevent ectopic Slit2 expression. Loss of Nf2 causes malformation of midline guideposts and Slit2 upregulation, resulting in callosal agenesis. Slit2 heterozygosity and Yap deletion both restore callosal formation in Nf2 mutants. Furthermore, selectively elevating Yap activity in midline neural progenitors is sufficient to disrupt guidepost formation, upregulate Slit2 and prevent midline crossing. The Hippo pathway is known for its role in controlling organ growth and tumorigenesis. Our study identifies a novel role of this pathway in axon guidance. Moreover, by linking axon pathfinding and neural progenitor behaviors, our results provide an example of the intricate coordination between growth and wiring during brain development.
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Affiliation(s)
- Alfonso Lavado
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Michelle Ware
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Joshua Paré
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
| | - Xinwei Cao
- Department of Developmental Neurobiology, St. Jude Children's Research Hospital, Memphis, TN 38105, USA
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Blockus H, Chédotal A. The multifaceted roles of Slits and Robos in cortical circuits: from proliferation to axon guidance and neurological diseases. Curr Opin Neurobiol 2014; 27:82-8. [PMID: 24698714 DOI: 10.1016/j.conb.2014.03.003] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2014] [Revised: 02/17/2014] [Accepted: 03/09/2014] [Indexed: 11/20/2022]
Abstract
Slit repulsion, mediated by Robo receptors, is known to play a major role in axon guidance in the nervous system. However, recent studies have revealed that in the mammalian cortex these molecules are highly versatile and that their function extends far beyond axon guidance. They act at all phases of development to control neurogenesis, neuronal migration, axon patterning, dendritic outgrowth and spinogenesis. The expression of Robo receptors in cortical and thalamocortical axons (TCAs) is tightly regulated by a combination of transcription factors (TFs), proteases and activity. These findings also suggest that Slit and Robos have influenced the evolution of cortical circuits. Last, novel genetic evidence associates various neurological disorders, such as autism, to abnormal Slit/Robo signaling.
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Affiliation(s)
- Heike Blockus
- INSERM UMR_S968, Institut de la Vision, F-75012 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR_S968, Institut de la vision, F-75012, France; CNRS, UMR7210, F-75012 Paris, France
| | - Alain Chédotal
- INSERM UMR_S968, Institut de la Vision, F-75012 Paris, France; Sorbonne Universités, UPMC Univ Paris 06, UMR_S968, Institut de la vision, F-75012, France; CNRS, UMR7210, F-75012 Paris, France.
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18
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Suárez R, Gobius I, Richards LJ. Evolution and development of interhemispheric connections in the vertebrate forebrain. Front Hum Neurosci 2014; 8:497. [PMID: 25071525 PMCID: PMC4094842 DOI: 10.3389/fnhum.2014.00497] [Citation(s) in RCA: 109] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Accepted: 06/19/2014] [Indexed: 12/20/2022] Open
Abstract
Axonal connections between the left and right sides of the brain are crucial for bilateral integration of lateralized sensory, motor, and associative functions. Throughout vertebrate species, forebrain commissures share a conserved developmental plan, a similar position relative to each other within the brain and similar patterns of connectivity. However, major events in the evolution of the vertebrate brain, such as the expansion of the telencephalon in tetrapods and the origin of the six-layered isocortex in mammals, resulted in the emergence and diversification of new commissural routes. These new interhemispheric connections include the pallial commissure, which appeared in the ancestors of tetrapods and connects the left and right sides of the medial pallium (hippocampus in mammals), and the corpus callosum, which is exclusive to eutherian (placental) mammals and connects both isocortical hemispheres. A comparative analysis of commissural systems in vertebrates reveals that the emergence of new commissural routes may have involved co-option of developmental mechanisms and anatomical substrates of preexistent commissural pathways. One of the embryonic regions of interest for studying these processes is the commissural plate, a portion of the early telencephalic midline that provides molecular specification and a cellular scaffold for the development of commissural axons. Further investigations into these embryonic processes in carefully selected species will provide insights not only into the mechanisms driving commissural evolution, but also regarding more general biological problems such as the role of developmental plasticity in evolutionary change.
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Affiliation(s)
- Rodrigo Suárez
- Queensland Brain Institute, The University of QueenslandBrisbane, QLD, Australia
| | - Ilan Gobius
- Queensland Brain Institute, The University of QueenslandBrisbane, QLD, Australia
| | - Linda J. Richards
- Queensland Brain Institute, The University of QueenslandBrisbane, QLD, Australia
- School of Biomedical Sciences, The University of QueenslandBrisbane, QLD, Australia
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Abstract
SoxB1 sub-family of transcriptional regulators are expressed in progenitor (NP) cells throughout the neuroaxis and are generally downregulated during neuronal differentiation. Gain- and loss-of-function studies indicate that Sox1, Sox2 and Sox3 are key regulators of NP differentiation and that their roles in CNS development are largely redundant. Nevertheless, mutation of each SoxB1 individually results in a different array of CNS defects, raising the possibility that SoxB1 proteins have subtly different functions in NP cells. To explore the mechanism of SOXB1 functional redundancy, and to identify genes that are most sensitive to loss of the Sox3 gene, we performed genome wide expression profiling of Sox3 null NP cells. Nineteen genes with abnormal expression were identified, including the homeobox gene Dbx1. Analysis of Sox3 null embryos revealed that Dbx1 was significantly reduced in the neural tube and developing brain and that SOX3 bound directly to conserved elements associated with this gene in cultured NP cells and in vivo. These data define Dbx1 as a direct SOX3 target gene whose expression, intriguingly, is not fully rescued by other SOXB1 transcription factors, suggesting that there are inherent differences in SOXB1 protein activity.
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20
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Heparan sulfotransferases Hs6st1 and Hs2st keep Erk in check for mouse corpus callosum development. J Neurosci 2014; 34:2389-401. [PMID: 24501377 DOI: 10.1523/jneurosci.3157-13.2014] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The corpus callosum (CC) connects the left and right cerebral hemispheres in mammals and its development requires intercellular communication at the telencephalic midline mediated by signaling proteins. Heparan sulfate (HS) is a sulfated polysaccharide that decorates cell surface and extracellular matrix proteins and regulates the biological activity of numerous signaling proteins via sugar-protein interactions. HS is subject to regulated enzymatic sulfation and desulfation and an attractive, although not proven, hypothesis is that the biological activity of HS is regulated by a sugar sulfate code. Mutant mouse embryos lacking the heparan sulfotransferases Hs2st or Hs6st1 have severe CC phenotypes and form Probst bundles of noncrossing axons flanking large tangles of midline glial processes. Here, we identify a precocious accumulation of Sox9-expressing glial cells in the indusium griseum region and a corresponding depletion at the glial wedge associated with the formation of Probst bundles along the rostrocaudal axis in both mutants. Molecularly, we found a surprising hyperactivation of Erk signaling in Hs2st(-/-) (2-fold) and Hs6st1(-/-) (6-fold) embryonic telencephalon that was most striking at the midline, where Erk signaling is lowest in wild-types, and a 2-fold increase in Fgf8 protein levels in Hs6st1(-/-) embryos that could underpin Erk hyperactivation and excessive glial movement to the indusium griseum. The tightly linked Hs6st1(-/-) CC glial and axonal phenotypes can be rescued by genetic or pharmacological suppression of Fgf8/Erk axis components. Overall, our data fit a model in which Hs2st and Hs6st1 normally generate conditions conducive to CC development by generating an HS-containing environment that keeps Erk signaling in check.
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Amaniti EM, Fu C, Lewis S, Saisana M, Magnani D, Mason JO, Theil T. Expansion of the piriform cortex contributes to corticothalamic pathfinding defects in Gli3 conditional mutants. ACTA ACUST UNITED AC 2013; 25:460-71. [PMID: 24014668 DOI: 10.1093/cercor/bht244] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The corticothalamic and thalamocortical tracts play essential roles in the communication between the cortex and thalamus. During development, axons forming these tracts have to follow a complex path to reach their target areas. While much attention has been paid to the mechanisms regulating their passage through the ventral telencephalon, very little is known about how the developing cortex contributes to corticothalamic/thalamocortical tract formation. Gli3 encodes a zinc finger transcription factor widely expressed in telencephalic progenitors which has important roles in corticothalamic and thalamocortical pathfinding. Here, we conditionally inactivated Gli3 in dorsal telencephalic progenitors to determine its role in corticothalamic tract formation. In Emx1Cre;Gli3(fl/fl) mutants, only a few corticothalamic axons enter the striatum in a restricted dorsal domain. This restricted entry correlates with a medial expansion of the piriform cortex. Transplantation experiments showed that the expanded piriform cortex repels corticofugal axons. Moreover, expression of Sema5B, a chemorepellent for corticofugal axons produced by the piriform cortex, is similarly expanded. Finally, time course analysis revealed an expansion of the ventral pallial progenitor domain which gives rise to the piriform cortex. Hence, control of lateral cortical development by Gli3 at the progenitor level is crucial for corticothalamic pathfinding.
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Affiliation(s)
- Eleni-Maria Amaniti
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Chaoying Fu
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Sean Lewis
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Marina Saisana
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Dario Magnani
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - John O Mason
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
| | - Thomas Theil
- Centre for Integrative Physiology, University of Edinburgh, Edinburgh EH8 9XD, UK
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22
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Abstract
Commissural circuits are brain and spinal cord connections which interconnect the two sides of the central nervous system (CNS). They play essential roles in brain and spinal cord processing, ensuring left-right coordination and synchronization of information and commands. During the formation of neuronal circuits, all commissural neurons of the central nervous system must accomplish a common task, which is to project their axon onto the other side of the nervous system, across the midline that delineates the two halves of the CNS. How this task is accomplished has been the topic of extensive studies over the last past 20 years and remains one of the best models to investigate axon guidance mechanisms. In the first part of this review, I will introduce the commissural circuits, their general role in the physiology of the nervous system, and their recognized or suspected pathogenic properties in human diseases. In the second part of the review, I will concentrate on two commissural circuits, the spinal commissures and the corpus callosum, to detail the cellular and molecular mechanisms governing their formation, mostly during their navigation at the midline.
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