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Neupane S, Goto J, Berardinelli SJ, Ito A, Haltiwanger RS, Holdener BC. Hydrocephalus in mouse B3glct mutants is likely caused by defects in multiple B3GLCT substrates in ependymal cells and subcommissural organ. Glycobiology 2021; 31:988-1004. [PMID: 33909046 DOI: 10.1093/glycob/cwab033] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 04/06/2021] [Accepted: 04/10/2021] [Indexed: 12/22/2022] Open
Abstract
Peters plus syndrome, characterized by defects in eye and skeletal development with isolated cases of ventriculomegaly/hydrocephalus, is caused by mutations in the β3-glucosyltransferase (B3GLCT) gene. In the endoplasmic reticulum, B3GLCT adds glucose to O-linked fucose on properly folded Thrombospondin Type 1 Repeats (TSRs). The resulting glucose-fucose disaccharide is proposed to stabilize the TSR fold and promote secretion of B3GLCT substrates, with some substrates more sensitive than others to loss of glucose. Mouse B3glct mutants develop hydrocephalus at high frequency. In this study, we demonstrated that B3glct mutant ependymal cells had fewer cilia basal bodies and altered translational polarity compared to controls. Localization of mRNA encoding A Disintegrin and Metalloproteinase with ThromboSpondin type 1 repeat 20 (ADAMTS20) and ADAMTS9, suggested that reduced function of these B3GLCT substrates contributed to ependymal cell abnormalities. In addition, we showed that multiple B3GLCT substrates (Adamts3, Adamts9, and Adamts20) are expressed by the subcommissural organ, that subcommissural organ-spondin (SSPO) TSRs were modified with O-linked glucose-fucose, and that loss of B3GLCT reduced secretion of SSPO in cultured cells. In the B3glct mutant subcommissural organ intracellular SSPO levels were reduced and BiP levels increased, suggesting a folding defect. Secreted SSPO colocalized with BiP, raising the possibility that abnormal extracellular assembly of SSPO into Reissner's fiber also contributed to impaired CSF flow in mutants. Combined, these studies underscore the complexity of the B3glct mutant hydrocephalus phenotype and demonstrate that impaired cerebrospinal fluid (CSF) flow likely stems from the collective effects of the mutation on multiple processes.
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Affiliation(s)
- Sanjiv Neupane
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY
| | - June Goto
- Division of Neurosurgery, Cincinnati Children's Hospital Medical Center, Cincinnati, OH
| | - Steven J Berardinelli
- Complex Carbohydrate Research Center, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA
| | - Atsuko Ito
- Complex Carbohydrate Research Center, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA
| | - Robert S Haltiwanger
- Complex Carbohydrate Research Center, Department of Biochemistry and Molecular Biology, University of Georgia, Athens, GA
| | - Bernadette C Holdener
- Department of Biochemistry and Cell Biology, Stony Brook University, Stony Brook, NY
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Rose CD, Pompili D, Henke K, Van Gennip JLM, Meyer-Miner A, Rana R, Gobron S, Harris MP, Nitz M, Ciruna B. SCO-Spondin Defects and Neuroinflammation Are Conserved Mechanisms Driving Spinal Deformity across Genetic Models of Idiopathic Scoliosis. Curr Biol 2020; 30:2363-2373.e6. [PMID: 32386528 DOI: 10.1016/j.cub.2020.04.020] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2019] [Revised: 03/05/2020] [Accepted: 04/08/2020] [Indexed: 12/23/2022]
Abstract
Adolescent idiopathic scoliosis (AIS) affects 3% to 4% of children between the ages of 11 and 18 [1, 2]. This disorder, characterized by abnormal three-dimensional spinal curvatures that typically develop during periods of rapid growth, occurs in the absence of congenital vertebral malformations or neuromuscular defects [1]. Genetic heterogeneity [3] and a historical lack of appropriate animal models [4] have confounded basic understanding of AIS biology; thus, treatment options remain limited [5, 6]. Recently, genetic studies using zebrafish have linked idiopathic-like scoliosis to irregularities in motile cilia-mediated cerebrospinal fluid flow [7-9]. However, because loss of cilia motility in human primary ciliary dyskinesia patients is not fully associated with scoliosis [10, 11], other pathogenic mechanisms remain to be determined. Here, we demonstrate that zebrafish scospondin (sspo) mutants develop late-onset idiopathic-like spinal curvatures in the absence of obvious cilia motility defects. Sspo is a large secreted glycoprotein functionally associated with the subcommissural organ and Reissner's fiber [12]-ancient and enigmatic organs of the brain ventricular system reported to govern cerebrospinal fluid homeostasis [13, 14], neurogenesis [12, 15-18], and embryonic morphogenesis [19]. We demonstrate that irregular deposition of Sspo within brain ventricles is associated with idiopathic-like scoliosis across diverse genetic models. Furthermore, Sspo defects are sufficient to induce oxidative stress and neuroinflammatory responses implicated in AIS pathogenesis [9]. Through screening for chemical suppressors of sspo mutant phenotypes, we also identify potent agents capable of blocking severe juvenile spine deformity. Our work thus defines a new preclinical model of AIS and provides tools to realize novel therapeutic strategies.
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Affiliation(s)
- Chloe D Rose
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
| | - David Pompili
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Katrin Henke
- Department of Orthopedic Research, Boston Children's Hospital, Boston, MA 02115, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Jenica L M Van Gennip
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Anne Meyer-Miner
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada
| | - Rahul Rana
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 3H6, Canada
| | | | - Matthew P Harris
- Department of Orthopedic Research, Boston Children's Hospital, Boston, MA 02115, USA; Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Mark Nitz
- Department of Chemistry, The University of Toronto, Toronto, ON M5S 3H6, Canada
| | - Brian Ciruna
- Program in Developmental & Stem Cell Biology, The Hospital for Sick Children, 686 Bay Street, Toronto, ON M5G 0A4, Canada; Department of Molecular Genetics, The University of Toronto, Toronto, ON M5S 1A8, Canada.
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Vidovic D, Harris L, Harvey TJ, Evelyn Heng YH, Smith AG, Osinski J, Hughes J, Thomas P, Gronostajski RM, Bailey TL, Piper M. Expansion of the lateral ventricles and ependymal deficits underlie the hydrocephalus evident in mice lacking the transcription factor NFIX. Brain Res 2015; 1616:71-87. [DOI: 10.1016/j.brainres.2015.04.057] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2014] [Revised: 04/20/2015] [Accepted: 04/29/2015] [Indexed: 11/29/2022]
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Grondona JM, Hoyo-Becerra C, Visser R, Fernández-Llebrez P, López-Ávalos MD. The subcommissural organ and the development of the posterior commissure. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2012; 296:63-137. [PMID: 22559938 DOI: 10.1016/b978-0-12-394307-1.00002-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
Growing axons navigate through the developing brain by means of axon guidance molecules. Intermediate targets producing such signal molecules are used as guideposts to find distal targets. Glial, and sometimes neuronal, midline structures represent intermediate targets when axons cross the midline to reach the contralateral hemisphere. The subcommissural organ (SCO), a specialized neuroepithelium located at the dorsal midline underneath the posterior commissure, releases SCO-spondin, a large glycoprotein belonging to the thrombospondin superfamily that shares molecular domains with axonal pathfinding molecules. Several evidences suggest that the SCO could be involved in the development of the PC. First, both structures display a close spatiotemporal relationship. Second, certain mutants lacking an SCO present an abnormal PC. Third, some axonal guidance molecules are expressed by SCO cells. Finally, SCO cells, the Reissner's fiber (the aggregated form of SCO-spondin), or synthetic peptides from SCO-spondin affect the neurite outgrowth or neuronal aggregation in vitro.
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Affiliation(s)
- Jesús M Grondona
- Departamento de Biología Celular, Genética y Fisiología, Facultad de Ciencias, Universidad de Málaga, Spain.
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Lee K, Tan J, Morris MB, Rizzoti K, Hughes J, Cheah PS, Felquer F, Liu X, Piltz S, Lovell-Badge R, Thomas PQ. Congenital hydrocephalus and abnormal subcommissural organ development in Sox3 transgenic mice. PLoS One 2012; 7:e29041. [PMID: 22291885 PMCID: PMC3266892 DOI: 10.1371/journal.pone.0029041] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2011] [Accepted: 11/18/2011] [Indexed: 12/24/2022] Open
Abstract
Congenital hydrocephalus (CH) is a life-threatening medical condition in which excessive accumulation of CSF leads to ventricular expansion and increased intracranial pressure. Stenosis (blockage) of the Sylvian aqueduct (Aq; the narrow passageway that connects the third and fourth ventricles) is a common form of CH in humans, although the genetic basis of this condition is unknown. Mouse models of CH indicate that Aq stenosis is associated with abnormal development of the subcommmissural organ (SCO) a small secretory organ located at the dorsal midline of the caudal diencephalon. Glycoproteins secreted by the SCO generate Reissner's fibre (RF), a thread-like structure that descends into the Aq and is thought to maintain its patency. However, despite the importance of SCO function in CSF homeostasis, the genetic program that controls SCO development is poorly understood. Here, we show that the X-linked transcription factor SOX3 is expressed in the murine SCO throughout its development and in the mature organ. Importantly, overexpression of Sox3 in the dorsal diencephalic midline of transgenic mice induces CH via a dose-dependent mechanism. Histological, gene expression and cellular proliferation studies indicate that Sox3 overexpression disrupts the development of the SCO primordium through inhibition of diencephalic roof plate identity without inducing programmed cell death. This study provides further evidence that SCO function is essential for the prevention of hydrocephalus and indicates that overexpression of Sox3 in the dorsal midline alters progenitor cell differentiation in a dose-dependent manner.
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Affiliation(s)
- Kristie Lee
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
| | - Jacqueline Tan
- Pituitary Research Unit, Murdoch Childrens Research Institute, Melbourne, Australia
| | - Michael B. Morris
- Bosch Institute and Physiology, University of Sydney, Sydney, Australia
- Kolling Institute of Medical Research and Sydney Centre for Development and Regenerative Medicine, Royal North Shore Hospital, Sydney, Australia
| | - Karine Rizzoti
- Division of Stem Cell Biology and Developmental Genetics, Medical Research Council National Institute for Medical Research, London, United Kingdom
| | - James Hughes
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
| | - Pike See Cheah
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
- Department of Human Anatomy, Universiti Putra Malaysia, Serdang, Malaysia
| | - Fernando Felquer
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
| | - Xuan Liu
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
| | - Sandra Piltz
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
| | - Robin Lovell-Badge
- Division of Stem Cell Biology and Developmental Genetics, Medical Research Council National Institute for Medical Research, London, United Kingdom
| | - Paul Q. Thomas
- School of Molecular and Biomedical Science, University of Adelaide, Adelaide, Australia
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