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The Cerebellum in Niemann-Pick C1 Disease: Mouse Versus Man. CEREBELLUM (LONDON, ENGLAND) 2023; 22:102-119. [PMID: 35040097 DOI: 10.1007/s12311-021-01347-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 11/17/2021] [Indexed: 02/01/2023]
Abstract
Selective neuronal vulnerability is common to most degenerative disorders, including Niemann-Pick C (NPC), a rare genetic disease with altered intracellular trafficking of cholesterol. Purkinje cell dysfunction and loss are responsible for cerebellar ataxia, which is among the prevailing neurological signs of the NPC disease. In this review, we focus on some questions that are still unresolved. First, we frame the cerebellar vulnerability in the context of the extended postnatal time length by which the development of this structure is completed in mammals. In line with this thought, the much later development of cerebellar symptoms in humans is due to the later development and/or maturation of the cerebellum. Hence, the occurrence of developmental events under a protracted condition of defective intracellular cholesterol mobilization hits the functional maturation of the various cell types generating the ground of increased vulnerability. This is particularly consistent with the high cholesterol demand required for cell proliferation, migration, differentiation, and synapse formation/remodeling. Other major questions we address are why the progression of Purkinje cells loss is always from the anterior to the posterior lobes and why cerebellar defects persist in the mouse model even when genetic manipulations can lead to nearly normal survival.
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Kamino D, Chau V, Studholme C, Liu M, Xu D, James Barkovich A, Ferriero DM, Miller SP, Brant R, Tam EW. Plasma cholesterol levels and brain development in preterm newborns. Pediatr Res 2019; 85:299-304. [PMID: 30635642 PMCID: PMC6433157 DOI: 10.1038/s41390-018-0260-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 11/30/2018] [Indexed: 11/30/2022]
Abstract
BACKGROUND To assess whether postnatal plasma cholesterol levels are associated with microstructural and macrostructural regional brain development in preterm newborns. METHODS Sixty preterm newborns (born 24-32 weeks gestational age) were assessed using MRI studies soon after birth and again at term-equivalent age. Blood samples were obtained within 7 days of each MRI scan to analyze for plasma cholesterol and lathosterol (a marker of endogenous cholesterol synthesis) levels. Outcomes were assessed at 3 years using the Bayley Scales of Infant Development, Third Edition. RESULTS Early plasma lathosterol levels were associated with increased axial and radial diffusivities and increased volume of the subcortical white matter. Early plasma cholesterol levels were associated with increased volume of the cerebellum. Early plasma lathosterol levels were associated with a 2-point decrease in motor scores at 3 years. CONCLUSIONS Higher early endogenous cholesterol synthesis is associated with worse microstructural measures and larger volumes in the subcortical white matter that may signify regional edema and worse motor outcomes. Higher early cholesterol is associated with improved cerebellar volumes. Further work is needed to better understand how the balance of cholesterol supply and endogenous synthesis impacts preterm brain development, especially if these may be modifiable factors to improve outcomes.
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Affiliation(s)
- Daphne Kamino
- Department of Paediatrics, Division of Neurology Hospital for Sick Children, Toronto, Ontario, Canada
| | - Vann Chau
- Department of Paediatrics, Division of Neurology Hospital for Sick Children, Toronto, Ontario, Canada
| | - Colin Studholme
- Department of Pediatrics and Department of Bioengineering and Radiology, University of Washington, Seattle, WA
| | - Mengyuan Liu
- Department of Pediatrics and Department of Bioengineering and Radiology, University of Washington, Seattle, WA
| | - Duan Xu
- Departments of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA
| | - A. James Barkovich
- Departments of Radiology and Biomedical Imaging, University of California San Francisco, San Francisco, CA,Departments of Pediatrics and Neurology, University of California San Francisco, San Francisco, CA
| | - Donna M. Ferriero
- Departments of Pediatrics and Neurology, University of California San Francisco, San Francisco, CA
| | - Steven P. Miller
- Department of Paediatrics, Division of Neurology Hospital for Sick Children, Toronto, Ontario, Canada,Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Rollin Brant
- Department of Statistics, University of British Columbia, Vancouver, British Columbia, Canada
| | - Emily W.Y. Tam
- Department of Paediatrics, Division of Neurology Hospital for Sick Children, Toronto, Ontario, Canada,Corresponding Author: Emily W.Y. Tam, MDCM, MAS, FRCPC, Hospital for Sick Children, Division of Neurology, 555 University Avenue, Toronto, ON M5G 1X8 Canada, Phone: 416-813-6660, Fax:416-813-6334,
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3
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Salama GS, Kaabneh MA, Al-Raqad MK, Al-Abdallah IM, Shakkoury AG, Halaseh RA. Cyclopia: a rare condition with unusual presentation - a case report. CLINICAL MEDICINE INSIGHTS-PEDIATRICS 2015; 9:19-23. [PMID: 25698887 PMCID: PMC4324465 DOI: 10.4137/cmped.s21107] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/23/2014] [Revised: 12/21/2014] [Accepted: 12/30/2014] [Indexed: 11/17/2022]
Abstract
INTRODUCTION Cyclopia (alobar holoprosencephaly) (OMIM% 236100) is a rare and lethal complex human malformation, resulting from incomplete cleavage of prosencephalon into right and left hemispheres occurring between the 18th and the 28th day of gestation. Holoprosencephaly occurs in 1/16,000 live births, and 1/250 during embryogenesis. Approximately 1.05 in 100,000 births are identified as infants with cyclopia, including stillbirths. Cyclopia typically presents with a median single eye or a partially divided eye in a single orbit, absent nose, and a proboscis above the eye. Extracranial malformations described in stillbirths with cyclopia include polydactyl, renal dysplasia, and an omphalocele. The etiology of this rare syndrome, which is incompatible with life, is still largely unknown. Most cases are sporadic. Heterogeneous risk factors have been implicated as possible causes. CASE PRESENTATION A live full-term baby with birth weight of 2900 g, product of cesarean section because of severe fetal bradycardia, was born at Prince Hashem Military Hospital – Zarqa city/Jordan. This newborn was the first baby to a non-consanguineous family, and a healthy 18-year-old mother, with no history of drug ingestion or febrile illnesses during pregnancy. Antenatal history revealed severe hydrocephalus diagnosed early by intrauterine ultrasound but the pregnancy was not terminated because of the lack of medical legitimization in the country. On examination, the newborn was found to have a dysmorphic face, with a median single eye, absence of nose, micrognathia, and a proboscis above the eye, all of which made cyclopia the possible initial diagnosis. Multiple unusual abdominal defects were present that include a huge omphalocele containing whole liver and spleen, urinary bladder extrophy, and undefined abnormal external genitalia, which called for urgent confirmation. Brain MRI was done and revealed findings consistent with alobar holoprosencephaly (cyclopia). CONCLUSION Presentation of cyclopia is not fully exposed and new cyclopian syndromes still can appear. The prenatal diagnosis of cyclopia can be made early by ultrasound, and the awareness of the spectrum of sonographic findings of cyclopia can improve the accuracy of prenatal diagnosis. The legitimization of pregnancy termination for indexed cases in many countries around the world should be revised.
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Affiliation(s)
| | | | | | | | | | - Ruba Aa Halaseh
- Paediatric Department, Royal Medical Services, Amman, Jordan
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4
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Vinkler C, Leshinsky-Silver E, Michelson M, Haas D, Lerman-Sagie T, Lev D. A newly recognized syndrome of severe growth deficiency, microcephaly, intellectual disability, and characteristic facial features. Eur J Med Genet 2014; 57:288-92. [PMID: 24709618 DOI: 10.1016/j.ejmg.2014.03.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2013] [Accepted: 03/25/2014] [Indexed: 10/25/2022]
Abstract
Genetic syndromes with proportionate severe short stature are rare. We describe two sisters born to nonconsanguineous parents with severe linear growth retardation, poor weight gain, microcephaly, characteristic facial features, cutaneous syndactyly of the toes, high myopia, and severe intellectual disability. During infancy and early childhood, the girls had transient hepatosplenomegaly and low blood cholesterol levels that normalized later. A thorough evaluation including metabolic studies, radiological, and genetic investigations were all normal. Cholesterol metabolism and transport were studied and no definitive abnormality was found. No clinical deterioration was observed and no metabolic crises were reported. After due consideration of other known hereditary causes of post-natal severe linear growth retardation, microcephaly, and intellectual disability, we propose that this condition represents a newly recognized autosomal recessive multiple congenital anomaly-intellectual disability syndrome.
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Affiliation(s)
- Chana Vinkler
- Institute of Medical Genetics, Wolfson Medical Center, Holon, Israel; Metabolic Neurogenetic Service, Wolfson Medical Center, Holon, Israel.
| | - Esther Leshinsky-Silver
- Metabolic Neurogenetic Service, Wolfson Medical Center, Holon, Israel; Molecular Genetics Laboratory, Wolfson Medical Center, Holon, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Marina Michelson
- Institute of Medical Genetics, Wolfson Medical Center, Holon, Israel; Metabolic Neurogenetic Service, Wolfson Medical Center, Holon, Israel
| | - Dorothea Haas
- Division of Inborn Metabolic Diseases, University Children's Hospital, Im Neuenheimer Feld, Heidelberg, Germany
| | - Tally Lerman-Sagie
- Metabolic Neurogenetic Service, Wolfson Medical Center, Holon, Israel; Pediatric Neurology Unit, Wolfson Medical Center, Holon, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Dorit Lev
- Institute of Medical Genetics, Wolfson Medical Center, Holon, Israel; Metabolic Neurogenetic Service, Wolfson Medical Center, Holon, Israel; Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel.
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5
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Swatek J, Szumiło J, Burdan F. Alobar holoprosencephaly with cyclopia – Autopsy-based observations from one medical center. Reprod Toxicol 2013; 41:80-5. [DOI: 10.1016/j.reprotox.2013.06.060] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2013] [Revised: 05/27/2013] [Accepted: 06/06/2013] [Indexed: 11/15/2022]
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Opitz JM, Furtado LV. The RSH/"Smith-Lemli-Opitz" syndrome: historical footnote. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2012; 160C:242-9. [PMID: 23059855 DOI: 10.1002/ajmg.c.31341] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
Thirty years after its clinical delineation in humans and its teratologic simulation in rats, a Garrodian error of metabolism was discovered in the autosomal recessive RSH/SLO syndrome, namely defective conversion of 7-dehydrocholesterol to cholesterol due to the mutant 7-dehydrocholesterol reductase. This opened the door to the study of several other defects of sterol biosynthesis in humans and the creation of animal "models." The gross discrepancy between expected and observed birth prevalence suggests high embryolethality. The discovery of the role of cholesterol in the synthesis of the morphogen sonic hedgehog has greatly advanced our understanding of mammalian development.
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Affiliation(s)
- John M Opitz
- American Journal of Medical Genetics, University of Utah, 419 Wakara Way, Ste 213, Salt Lake City, UT 84108, USA.
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7
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Biomarkers of teratogenesis: Suggestions from animal studies. Reprod Toxicol 2012; 34:180-5. [DOI: 10.1016/j.reprotox.2012.05.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2012] [Revised: 05/03/2012] [Accepted: 05/10/2012] [Indexed: 12/19/2022]
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8
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Horvat S, Mcwhir J, Rozman D. Defects in cholesterol synthesis genes in mouse and in humans: lessons for drug development and safer treatments. Drug Metab Rev 2011; 43:69-90. [DOI: 10.3109/03602532.2010.540580] [Citation(s) in RCA: 52] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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9
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Basu S, Kumar A, Das BK. Down syndrome (trisomy 21) with premaxillary agenesis and semilobar holoprosencephaly. Am J Med Genet A 2009; 149A:2578-80. [PMID: 19876909 DOI: 10.1002/ajmg.a.33072] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Affiliation(s)
- Sriparna Basu
- Department of Pediatrics, Institute of Medical Sciences, Banaras Hindu University, Varanasi, India.
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Vaillant C, Monard D. SHH pathway and cerebellar development. THE CEREBELLUM 2009; 8:291-301. [PMID: 19224309 DOI: 10.1007/s12311-009-0094-8] [Citation(s) in RCA: 84] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/17/2008] [Accepted: 01/14/2009] [Indexed: 12/22/2022]
Abstract
The morphogenetic factor Sonic hedgehog (SHH) has been discovered as one of the masterplayers in cerebellar patterning and was subjected to intensive investigation during the last decade. During early postnatal development, this continuously secreted cholesterol-modified protein drives the expansion of the largest neuronal population of the brain, the granular cells. Moreover, it acts on Bergmann glia differentiation and would potentially affect Purkinje cells homeostasis at adult age. The cerebellar cortex constituted an ideal developmental model to dissect out the upstream mechanisms and downstream targets of this complex pathway. Its deep understanding discloses some of the mechanistic disorders underlying pediatric tumorigenesis, congenital ataxia, and mental retardation. Therapeutical use of its regulators has been consolidated on murine transgenic models and is now considered as a realistic human clinical application. Here, we will review the most recent advances made in the comprehensive understanding of SHH involvement in cerebellar development and pathology.
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Affiliation(s)
- Catherine Vaillant
- Developmental Genetics, Department Biomedicine, University of Basel, CH-4058 Basel, Switzerland
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11
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Dubourg C, Bendavid C, Pasquier L, Henry C, Odent S, David V. Holoprosencephaly. Orphanet J Rare Dis 2007; 2:8. [PMID: 17274816 PMCID: PMC1802747 DOI: 10.1186/1750-1172-2-8] [Citation(s) in RCA: 263] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/01/2006] [Accepted: 02/02/2007] [Indexed: 12/14/2022] Open
Abstract
Holoprosencephaly (HPE) is a complex brain malformation resulting from incomplete cleavage of the prosencephalon, occurring between the 18th and the 28th day of gestation and affecting both the forebrain and the face. It is estimated to occur in 1/16,000 live births and 1/250 conceptuses. Three ranges of increasing severity are described: lobar, semi-lobar and alobar HPE. Another milder subtype of HPE called middle interhemispheric variant (MIHF) or syntelencephaly is also reported. In most of the cases, facial anomalies are observed in HPE, like cyclopia, proboscis, median or bilateral cleft lip/palate in severe forms, ocular hypotelorism or solitary median maxillary central incisor in minor forms. These latter midline defects can occur without the cerebral malformations and then are called microforms. Children with HPE have many medical problems: developmental delay and feeding difficulties, epilepsy, instability of temperature, heart rate and respiration. Endocrine disorders like diabetes insipidus, adrenal hypoplasia, hypogonadism, thyroid hypoplasia and growth hormone deficiency are frequent. To date, seven genes have been positively implicated in HPE: Sonic hedgehog (SHH), ZIC2, SIX3, TGIF, PTCH, GLI2 and TDGF1. A molecular diagnosis can be performed by gene sequencing and allele quantification for the four main genes SHH, ZIC2, SIX3 and TGIF. Major rearrangements of the subtelomeres can also be identified by multiplex ligation-dependent probe amplification (MLPA). Nevertheless, in about 70% of cases, the molecular basis of the disease remains unknown, suggesting the existence of several other candidate genes or environmental factors. Consequently, a "multiple-hit hypothesis" of genetic and/or environmental factors (like maternal diabetes) has been proposed to account for the extreme clinical variability. In a practical approach, prenatal diagnosis is based on ultrasound and magnetic resonance imaging (MRI) rather than on molecular diagnosis. Treatment is symptomatic and supportive, and requires a multidisciplinary management. Child outcome depends on the HPE severity and the medical and neurological complications associated. Severely affected children have a very poor prognosis. Mildly affected children may exhibit few symptoms and may live a normal life.
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Affiliation(s)
- Christèle Dubourg
- UMR 6061 CNRS, Institut de Génétique et Développement de Rennes, Université de Rennes1, IFR 140 GFAS, Faculté de Médecine, Rennes, 35000, France
- Laboratoire de Génétique Moléculaire et Hormonologie, Centre Hospitalier et Universitaire de Pontchaillou, Rennes, 35000, France
| | - Claude Bendavid
- UMR 6061 CNRS, Institut de Génétique et Développement de Rennes, Université de Rennes1, IFR 140 GFAS, Faculté de Médecine, Rennes, 35000, France
- Laboratoire de Génétique Moléculaire et Hormonologie, Centre Hospitalier et Universitaire de Pontchaillou, Rennes, 35000, France
| | - Laurent Pasquier
- Service de Génétique Médicale, Hôpital Sud, Rennes, 35000, France
| | - Catherine Henry
- Laboratoire de Cytogénétique, Centre Hospitalier et Universitaire de Pontchaillou, Rennes, 35000, France
| | - Sylvie Odent
- Service de Génétique Médicale, Hôpital Sud, Rennes, 35000, France
| | - Véronique David
- UMR 6061 CNRS, Institut de Génétique et Développement de Rennes, Université de Rennes1, IFR 140 GFAS, Faculté de Médecine, Rennes, 35000, France
- Laboratoire de Génétique Moléculaire et Hormonologie, Centre Hospitalier et Universitaire de Pontchaillou, Rennes, 35000, France
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Bijlsma MF, Spek CA, Zivkovic D, van de Water S, Rezaee F, Peppelenbosch MP. Repression of smoothened by patched-dependent (pro-)vitamin D3 secretion. PLoS Biol 2006; 4:e232. [PMID: 16895439 PMCID: PMC1502141 DOI: 10.1371/journal.pbio.0040232] [Citation(s) in RCA: 223] [Impact Index Per Article: 12.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/29/2005] [Accepted: 05/08/2006] [Indexed: 12/04/2022] Open
Abstract
The developmentally important hedgehog (Hh) pathway is activated by binding of Hh to patched (Ptch1), releasing smoothened (Smo) and the downstream transcription factor glioma associated (Gli) from inhibition. The mechanism behind Ptch1-dependent Smo inhibition remains unresolved. We now show that by mixing Ptch1-transfected and Ptch1 small interfering RNA–transfected cells with Gli reporter cells, Ptch1 is capable of non–cell autonomous repression of Smo. The magnitude of this non–cell autonomous repression of Smo activity was comparable to the fusion of Ptch1-transfected cell lines and Gli reporter cell lines, suggesting that it is the predominant mode of action. CHOD-PAP analysis of medium conditioned by Ptch1-transfected cells showed an elevated 3β-hydroxysteroid content, which we hypothesized to mediate the Smo inhibition. Indeed, the inhibition of 3β-hydroxysteroid synthesis impaired Ptch1 action on Smo, whereas adding the 3β-hydroxysteroid (pro-)vitamin D3 to the medium effectively inhibited Gli activity. Vitamin D3 bound to Smo with high affinity in a cyclopamine-sensitive manner. Treating zebrafish embryos with vitamin D3 mimicked the
smo–/– phenotype, confirming the inhibitory action in vivo. Hh activates its signalling cascade by inhibiting Ptch1-dependent secretion of the 3β-hydroxysteroid (pro-)vitamin D3. This action not only explains the seemingly contradictory cause of Smith-Lemli-Opitz syndrome (SLOS), but also establishes Hh as a unique morphogen, because binding of Hh on one cell is capable of activating Hh-dependent signalling cascades on other cells.
The authors show that patched can inhibit smoothened activity by promoting transport of Vitamin D3 (which binds Smo), addressing a long-standing mystery in hedgehog signaling. This inhibition can occur in a non-cell-autonomous manner.
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Affiliation(s)
- Maarten F Bijlsma
- Center for Experimental and Molecular Medicine, Academic Medical Center, University of Amsterdam, Meibergdreef, Amsterdam, Netherlands.
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Fernández C, Martín M, Gómez-Coronado D, Lasunción MA. Effects of distal cholesterol biosynthesis inhibitors on cell proliferation and cell cycle progression. J Lipid Res 2005; 46:920-9. [PMID: 15687348 DOI: 10.1194/jlr.m400407-jlr200] [Citation(s) in RCA: 71] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Cholesterol is a major lipid component of the plasma membrane in animal cells. In addition to its structural requirement, cholesterol is essential in cell proliferation and other cell processes. The aim of the present study was to elucidate the stringency of the requirement for cholesterol as a regulator of proliferation and cell cycle progression, compared with other sterols of the cholesterol biosynthesis pathway. Human promyelocytic HL-60 cells were cultured in cholesterol-free medium and treated with different distal inhibitors of cholesterol biosynthesis (zaragozic acid, SKF 104976, SR 31747, BM 15766, and AY 9944), which allow the synthesis of isoprenoid derivatives and different sets of sterol intermediates, but not cholesterol. The results showed that only the inhibition of sterol Delta7-reductase was compatible with cell proliferation. Blocking cholesterol biosynthesis upstream of this enzyme resulted in the inhibition of cell proliferation and cell cycle arrest selectively in G2/M phase.
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Affiliation(s)
- Carlos Fernández
- Servicio de Bioquímica-Investigación, Hospital Ramón y Cajal, 28034 Madrid, Spain
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14
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Abstract
Cell signaling plays a key role in the development of all multicellular organisms. Numerous studies have established the importance of Hedgehog signaling in a wide variety of regulatory functions during the development of vertebrate and invertebrate organisms. Several reviews have discussed the signaling components in this pathway, their various interactions, and some of the general principles that govern Hedgehog signaling mechanisms. This review focuses on the developing systems themselves, providing a comprehensive survey of the role of Hedgehog signaling in each of these. We also discuss the increasing significance of Hedgehog signaling in the clinical setting.
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Affiliation(s)
- Andrew P McMahon
- Department of Molecular and Cellular Biology, Harvard University, Cambridge, Massachusetts 02138, USA.
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15
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Chevy F, Illien F, Wolf C, Roux C. Limb malformations of rat fetuses exposed to a distal inhibitor of cholesterol biosynthesis. J Lipid Res 2002. [DOI: 10.1194/jlr.m200082-jlr200] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
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16
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Mirshahi M, Ayani E, Nicolas C, Golestaneh N, Ferrari P, Valamanesh F, Agarwal MK. The blockade of mineralocorticoid hormone signaling provokes dramatic teratogenesis in cultured rat embryos. Int J Toxicol 2002; 21:191-9. [PMID: 12055020 DOI: 10.1080/10915810290096324] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
Although the administration of adrenocortical hormones to pregnant rats provokes only limited effect on the growth and development of the fetus, the direct influence of these steroids on cultured embryos has never been studied. The disruption of cell signaling by ZK 91587, which specifically occupies the mineralocorticoid receptor, resulted within 2 days in significant and pronounced adverse effects on the total length, the somite number, the embryo curvature, the communication between vitelline and umbilical blood vessels in the allantoid, and the vascularization of the vitelline sac, in 244-hour Wistar rat embryos in culture. The average score of 16 organs declined in a dose-dependent manner, following exposure to ZK 91587, and this was totally reversed by 10 microM aldosterone which, by itself, did not at all influence the embryonic development. The organogenesis was inhibited in the order: hind limb > fore limb > optic stalk > brain > olfactory pit > otic vesicle. ZK 91587 was completely ineffective in embryos that had attained the age of 260 hours. Similar, but less dramatic, results were obtained with the mineralocorticoid antagonist RU 26752, and with the antiglucocorticoid RU 38486. Sprague-Dawley rat embryos responded in a manner similar to the Wistar conceptuses. Thus, steroid receptor-mediated cell signaling is of critical importance to the growth and development of cultured rat embryos, which form a new model system to unravel adrenocortical hormone action.
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Affiliation(s)
- M Mirshahi
- INSERM, Faculté de Médecine Paris VI, Paris, France.
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Evans T, Poh A, Webb C, Wainwright B, Wicking C, Glass I, Carey WF, Fietz M. Novel mutation in the ?7-dehydrocholesterol reductase gene in an Australian patient with Smith-Lemli-Opitz syndrome. ACTA ACUST UNITED AC 2001. [DOI: 10.1002/ajmg.1573] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Muenke M, Cohen MM. Genetic approaches to understanding brain development: holoprosencephaly as a model. MENTAL RETARDATION AND DEVELOPMENTAL DISABILITIES RESEARCH REVIEWS 2000; 6:15-21. [PMID: 10899793 DOI: 10.1002/(sici)1098-2779(2000)6:1<15::aid-mrdd3>3.0.co;2-8] [Citation(s) in RCA: 62] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Holoprosencephaly (HPE) is the most common major developmental defect of the forebrain in humans. Clinical expression is variable, ranging from a small brain with a single cerebral ventricle and cyclopia to clinically unaffected carriers in familial HPE. Significant etiologic heterogeneity exists in HPE and includes both genetic and environmental causes. Defects in the cell signaling pathway involving the Sonic Hedgehog (SHH) gene, as well as defects in the cholesterol biosynthesis have been shown to cause HPE in humans. More recently, HPE genes from additional signaling pathways have been identified. These discoveries and current genetic approaches serve as a paradigm for studying normal and abnormal brain morphogenesis. MRDD Research Reviews 6:15-21, 2000.
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Affiliation(s)
- M Muenke
- The Children's Hospital of Philadelphia, Division of Neurology, Philadelphia, Pennsylvania.
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Roux C, Wolf C, Mulliez N, Gaoua W, Cormier V, Chevy F, Citadelle D. Role of cholesterol in embryonic development. Am J Clin Nutr 2000; 71:1270S-9S. [PMID: 10799401 DOI: 10.1093/ajcn/71.5.1270s] [Citation(s) in RCA: 103] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
We showed previously that 3 distal inhibitors of cholesterol synthesis are highly teratogenic in rats. AY 9944 and BM 15766 inhibit 7-dehydrocholesterol reductase, which catalyzes the last step of cholesterol synthesis, and triparanol inhibits Delta(24)-dehydrocholesterol reductase, which catalyzes the last step in another pathway. These molecules cause holoprosencephalic brain anomalies. Under certain experimental conditions, other anomalies (of the limbs and male genitalia) are also observed. Assays performed by gas chromatography-mass spectrometry (GC-MS) show hypocholesterolemia and an accumulation of precursors. These data indicate that this animal model can be considered a model of Smith-Lemli-Opitz syndrome. Smith-Lemli-Opitz syndrome is a recessive autosomal genetic disease characterized by malformations (microcephaly, corpus callosum agenesis, holoprosencephaly, and mental retardation), male pseudohermaphroditism, finger anomalies, and failure to thrive. The syndrome has been attributed to a deficit in 7-dehydrocholesterol reductase. As assayed by GC-MS, the sterol status of these patients indicates severe hypocholesterolemia and an accumulation of precursors: 7-dehydrocholesterol, 8-dehydrocholesterol, and oxidized derivatives. The presence of 7-dehydrocholesterol in the serum of patients is pathognomonic of the disease. The developmental gene Shh (sonic hedgehog) plays a key role in brain, limb, and genital development; it was shown recently that the Shh protein has to be covalently linked to cholesterol to be active. This is the first time that a posttranslational function has been attributed to cholesterol. There is an obvious relation between Shh dysfunction and the malformations observed in our experiments and in patients with Smith-Lemli-Opitz syndrome. However, the exact relation remains to be clarified. It is clear, however, that the role of cholesterol in embryonic development must be taken into account.
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Affiliation(s)
- C Roux
- Laboratoire d'Embryologie Pathologique Expérimentale, CHU Saint-Antoine, Paris, France.
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20
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Cholesterol deficit but not accumulation of aberrant sterols is the major cause of the teratogenic activity in the Smith-Lemli-Opitz syndrome animal model. J Lipid Res 2000. [DOI: 10.1016/s0022-2275(20)32412-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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21
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Abstract
Holoprosencephaly is a malformation of the cerebral hemispheres resulting in the absence of the inter-hemispheric fissure along with other defects of brain development. Frequently midline defects of the craniofacial structures are also present. This malformation sequence has been of interest for many years because of the well recognized genetic and environmental pathogeneses, although the molecular pathogenesis remained elusive. Recent studies have begun clarifying the molecular pathogenesis of holoprosencephaly. Herein is reviewed the syndromes associated with holoprosencephaly, the pathology of this disorder, genetic and environment factors, and a current understanding of the molecular pathogenesis of this disorder.
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Affiliation(s)
- J A Golden
- Department of Pathology, Abramson Research Center, Children's Hospital of Philadelphia and the University of Pennsylvania School of Medicine, 19104, USA.
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22
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Gofflot F, Kolf-Clauw M, Clotman F, Roux C, Picard JJ. Absence of ventral cell populations in the developing brain in a rat model of the Smith-Lemli-Opitz syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS 1999; 87:207-16. [PMID: 10564872 DOI: 10.1002/(sici)1096-8628(19991126)87:3<207::aid-ajmg3>3.0.co;2-5] [Citation(s) in RCA: 23] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive condition involving craniofacial and central nervous system malformations with occasional holoprosencephaly (HPE). It is caused by a defect in the 7-dehydrocholesterol (7-DHC) reductase, the enzyme catalyzing the last step of cholesterol biosynthesis. Treatment of pregnant rats with inhibitors of 7-DHC reductase, either AY9944 or BM15.766, has provided a valuable model to study the pathogenesis in SLOS. Recently, cholesterol has been shown to be involved in the post-translational activation of the signaling protein Sonic Hedgehog. To identify the early defects associated with HPE in a rat model of SLOS, and to compare the phenotype of the treated embryos with that of the Shh(-/-) mutants, we examined brain morphology and expression of three developmental genes (Shh, Otx2, and Pax6 ) in 23-somite stage embryos from AY9944-treated dams. We report clearly abnormal morphology of the developing brain, concerning primarily the ventral aspect of the neural tube. We observed a reduced or absent expression of Shh and Otx2 in their ventral domain associated with extended ventral expression of Pax6. The results suggest an absence of the midline ventral cell type at all levels of the cranial neural tube. They provide further evidence that cholesterol-deficiency-induced HPE originates from impaired Shh signaling activity in the ventral neural tube.
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Affiliation(s)
- F Gofflot
- Unit of Developmental Genetics, Université Catholique de Louvain, Bruxelles, Belgium.
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23
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Tozawa R, Ishibashi S, Osuga J, Yagyu H, Oka T, Chen Z, Ohashi K, Perrey S, Shionoiri F, Yahagi N, Harada K, Gotoda T, Yazaki Y, Yamada N. Embryonic lethality and defective neural tube closure in mice lacking squalene synthase. J Biol Chem 1999; 274:30843-8. [PMID: 10521476 DOI: 10.1074/jbc.274.43.30843] [Citation(s) in RCA: 101] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Squalene synthase (SS) catalyzes the reductive head-to-head condensation of two molecules of farnesyl diphosphate to form squalene, the first specific intermediate in the cholesterol biosynthetic pathway. We used gene targeting to knock out the mouse SS gene. The mice heterozygous for the mutation (SS+/-) were apparently normal. SS+/- mice showed 60% reduction in the hepatic mRNA levels of SS compared with SS+/+ mice. Consistently, the SS enzymatic activities were reduced by 50% in the liver and testis. Nevertheless, the hepatic cholesterol synthesis was not different between SS+/- and SS+/+ mice, and plasma lipoprotein profiles were not different irrespective of the presence of the low density lipoprotein receptor, indicating that SS is not a rate-limiting enzyme in the cholesterol biosynthetic pathway. The mice homozygous for the disrupted SS gene (SS-/-) were embryonic lethal around midgestation. E9.5-10.5 SS-/- embryos exhibited severe growth retardation and defective neural tube closure. The lethal phenotype was not rescued by supplementing the dams either with dietary squalene or cholesterol. We speculate that cholesterol is required for the development, particularly of the nervous system, and that the chorioallantoic circulatory system is not mature enough to supply the rapidly growing embryos with maternal cholesterol at this developmental stage.
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Affiliation(s)
- R Tozawa
- Department of Metabolic Diseases, Faculty of Medicine, University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-8655, Japan
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24
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Abstract
Holoprosencephaly (HPE) is the most common developmental defect of the forebrain in humans. Several distinct human genes for holoprosencephaly have now been identified. They include Sonic hedgehog (SHH), ZIC2, and SIX3. Many additional genes involved in forebrain development are rapidly being cloned and characterized in model vertebrate organisms. These include Patched (Ptc), Smoothened (Smo), cubitus interuptus (ci)/Gli, wingless (wg/Wnt, decapentaplegic (dpp)/BMP, Hedgehog interacting protein (Hip), nodal, Smads, One-eyed pinhead (Oep), and TG-Interacting Factor (TGIF). However, further analysis is needed before their roles in HPE can be established. Here we present an overview of the presently known genes causing human holoprosencephaly and describe candidate genes involved in forebrain development identified in other systems. A model is discussed for how these genes may interact within and between several different signaling pathways to direct the formation of the forebrain.
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Affiliation(s)
- D E Wallis
- Departments of Pediatrics, Genetics, and Neurology, The Children's Hospital of Philadelphia, Philadelphia, Pennsylvania, 19104-4399, USA
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25
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Abstract
The molecular bases of brain development and CNS malignancies remain poorly understood. Here we show that Sonic hedgehog (Shh) signaling controls the development of the cerebellum at multiple levels. SHH is produced by Purkinje neurons, it is required for the proliferation of granule neuron precursors and it induces the differentiation of Bergmann glia. Blocking SHH function in vivo results in deficient granule neuron and Bergmann glia differentiation as well as in abnormal Purkinje neuron development. Thus, our findings provide a molecular model for the growth and patterning of the cerebellum by SHH through the coordination of the development of cortical cerebellar cell types. In addition, they provide a cellular context for medulloblastomas, childhood cancers of the cerebellum.
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Affiliation(s)
- N Dahmane
- The Skirball Institute, Developmental Genetics Program and Department of Cell Biology, NYU School of Medicine, New York, NY 10016, USA.
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26
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Gaoua W, Chevy F, Roux C, Wolf C. Oxidized derivatives of 7-dehydrocholesterol induce growth retardation in cultured rat embryos: a model for antenatal growth retardation in the Smith-Lemli-Opitz syndrome. J Lipid Res 1999. [DOI: 10.1016/s0022-2275(20)32450-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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27
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Abstract
Although cholesterol has long been known to be an essential component of cell membranes in vertebrate organisms, recent studies have suggested that cholesterol plays a crucial role in specific processes during embryonic development, including the covalent modification of Hedgehog proteins. Here we review the overlapping developmental phenotypes associated with pharmacologically or genetically induced defects in cholesterol biosynthesis, embryonic cholesterol transport and Hedgehog proteins. Shared aspects of these phenotypes suggest that common mechanisms underlie impaired central nervous system development associated with cholesterol deficiency.
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Affiliation(s)
- R V Farese
- Gladstone Institute of Cardiovascular Disease, University of California, San Francisco 94141, USA.
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28
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Abstract
Holoprosencephaly (HPE), a common developmental defect affecting the forebrain and face, is etiologically heterogeneous and exhibits wide phenotypic variation. Graded degrees of severity of the brain malformation are also reflected in the highly variable craniofacial malformations associated with HPE. In addition, individuals with microforms of HPE, who usually have normal cognition and normal brain imaging, are at risk for having children with HPE. Some obligate carriers for HPE may not have any phenotypic abnormalities. Recurrent chromosomal rearrangements in individuals with HPE suggest loci containing genes important for brain development, and abnormalities in these genes may result in HPE. Recently, Sonic Hedgehog (SHH) was the first gene identified as causing HPE in humans. Proper function of SHH depends on cholesterol modification. Other candidate genes that may be involved in HPE include components of the SHH pathway, elements involved in cholesterol metabolism, and genes expressed in the developing forebrain.
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Affiliation(s)
- J E Ming
- The Children's Hospital of Philadelphia, Department of Pediatrics, University of Pennsylvania School of Medicine, USA
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29
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Lanoue L, Dehart DB, Hinsdale ME, Maeda N, Tint GS, Sulik KK. Limb, genital, CNS, and facial malformations result from gene/environment-induced cholesterol deficiency: Further evidence for a link to sonic hedgehog. ACTA ACUST UNITED AC 1997. [DOI: 10.1002/(sici)1096-8628(19971128)73:1<24::aid-ajmg6>3.0.co;2-p] [Citation(s) in RCA: 90] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/02/2023]
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30
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Dehart DB, Lanoue L, Tint GS, Sulik KK. Pathogenesis of malformations in a rodent model for Smith-Lemli-Opitz syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS 1997; 68:328-37. [PMID: 9024568 DOI: 10.1002/(sici)1096-8628(19970131)68:3<328::aid-ajmg15>3.0.co;2-v] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The fact that Smith-Lemli-Opitz syndrome (SLOS), a syndrome comprising major malformations involving a number of organ systems, results from an abnormality in cholesterol biosynthesis, was discovered only recently. Utilizing a drug (BM 15.766) to inhibit the same step in cholesterol biosynthesis as is abnormal in those affected with SLOS, we have developed a rat model that presents with abnormalities observed as early as gestational day 12 that appear to be consistent with some of those subsequent malformations that comprise the human syndrome. Abnormalities of the brain and face include deficiency in the midline region of the upper face, narrowing of the forebrain hemispheres and of the cerebral aqueduct, and deficiency in the developing lower jaw. Associated pathogenesis, as observed on gestational day 11 in histological sections and with scanning electron microscopy, involves abnormal cell populations at the rim of the developing forebrain and in the alar plate of the lower midbrain and hind-brain. The affected cells appear abnormally rounded up, having apparently lost their normal cell contacts. The potential basis for the selective vulnerability of this cell population and the impact of its vulnerability relative to subsequent dysmorphogenesis is discussed.
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Affiliation(s)
- D B Dehart
- Department of Cell Biology and Anatomy, University of North Carolina at Chapel Hill 27599-7090, USA
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31
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Llirbat B, Wolf C, Chevy F, Citadelle D, Bereziat G, Roux C. Normal and inhibited cholesterol synthesis in the cultured rat embryo. J Lipid Res 1997. [DOI: 10.1016/s0022-2275(20)37272-2] [Citation(s) in RCA: 25] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022] Open
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32
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Tint GS, Batta AK, Xu G, Shefer S, Honda A, Irons M, Elias ER, Salen G. The Smith-Lemli-Opitz syndrome: a potentially fatal birth defect caused by a block in the last enzymatic step in cholesterol biosynthesis. Subcell Biochem 1997; 28:117-44. [PMID: 9090293 DOI: 10.1007/978-1-4615-5901-6_5] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Affiliation(s)
- G S Tint
- Research Service, Department of Veterans Affairs Medical Center, East Orange, New Jersey 07019, USA
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33
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Kelley RL, Roessler E, Hennekam RC, Feldman GL, Kosaki K, Jones MC, Palumbos JC, Muenke M. Holoprosencephaly in RSH/Smith-Lemli-Opitz syndrome: does abnormal cholesterol metabolism affect the function of Sonic Hedgehog? AMERICAN JOURNAL OF MEDICAL GENETICS 1996; 66:478-84. [PMID: 8989473 DOI: 10.1002/(sici)1096-8628(19961230)66:4<478::aid-ajmg22>3.0.co;2-q] [Citation(s) in RCA: 167] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
The RSH/Smith-Lemli-Opitz syndrome (RSH/SLOS) is an autosomal recessive malformation syndrome associated with increased levels of 7-dehydro-cholesterol (7-DHC) and a defect of cholesterol biosynthesis at the level of 3 beta-hydroxy-steroid-delta7-reductase (7-DHC reductase). Because rats exposed to inhibitors of 7-DHC reductase during development have a high frequency of holoprosencephaly (HPE) [Roux et al., 1979], we have undertaken a search for biochemical evidence of RSH/SLOS and other possible defects of sterol metabolism among patients with various forms of HPE. We describe 4 patients, one with semilobar HPE and three others with less complete forms of the HPE sequence, in whom we have made a biochemical diagnosis of RSH/SLOS. The clinical and biochemical spectrum of these and other patients with RSH/SLOS suggests a role of abnormal sterol metabolism in the pathogenesis of their malformations. The association of HPE and RSH/SLOS is discussed in light of the recent discoveries that mutations in the embryonic patterning gene, Sonic Hedgehog (SHH), can cause HPE in humans and that the sonic hedgehog protein product undergoes autoproteolysis to form a cholesterol-modified active product. These clinical, biochemical, and molecular studies suggest that HPE and other malformations in SLOS may be caused by incomplete or abnormal modification of the sonic hedgehog protein and, possible, other patterning proteins of the hedgehog class, a hypothesis testable in somatic cell systems.
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Affiliation(s)
- R L Kelley
- Kennedy Krieger Institute, Johns Hopkins University, Baltimore, Maryland, USA
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34
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Kolf-Clauw M, Chevy F, Wolf C, Siliart B, Citadelle D, Roux C. Inhibition of 7-dehydrocholesterol reductase by the teratogen AY9944: a rat model for Smith-Lemli-Opitz syndrome. TERATOLOGY 1996; 54:115-25. [PMID: 8987154 DOI: 10.1002/(sici)1096-9926(199609)54:3<115::aid-tera1>3.0.co;2-2] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Our aim is to verify the validity of a rat model proposed for Smith-Lemli-Opitz (SLO) syndrome, a developmental disorder characterized by a defect in 7-dehydrocholesterol-delta 7 (7DHC)-reductase and by facial dysmorphism close to the holoprosencephaly caused by the teratogen AY9944. We investigated the sterol profile in rats treated with AY9944 blocking 7DHC-reductase. AY9944 was given orally to rats on gestation day 3 (D3). The sera were sampled for kinetic data on D3, D6, D9, D12, and D21. Cholesterol was measured in parallel by the routine enzymatic method and by the gas chromatography/mass spectrometry (GC-MS) procedure used in SLO diagnosis. In addition to sterols, we dosed steroid hormones punctually on D4 and on D10, and examined D21 fetuses in other animals. The enzymatic method was not specific for cholesterol, and measured 70% pure 7DHC added to a normal serum. On D21, 77% live fetuses showed pituitary agenesis. Cholesterol was rapidly reduced by more than 50% on D6 involving an accumulation of 7DHC, 8DHC, and trienols, as identified in SLO-affected children. The most abundant 7DHC reached a maximum from D9 to D12, equaling cholesterol on D9 (11 mg/dl). On D10, the magnitudes of hypocholesterolemic and of 7DHC accumulation were found to be dose-dependent. Progesterone was reduced as early as 24 hr after treatment and dropped to 40% of the levels in the controls on D10, correlating to the decrease in cholesterolemia. This rat model reproduces the same biochemical perturbations as seen in SLO, strongly suggesting that aberrant sterols (7DHC, 8DHC, or nortrienol) may contribute to the developmental defects.
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Affiliation(s)
- M Kolf-Clauw
- Toxicology Department, Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France
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35
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Batta AK, Salen G. Characterization of the biochemical abnormality in the Smith-Lemli-Opitz syndrome. Indian J Pediatr 1996; 63:143-7. [PMID: 10829981 DOI: 10.1007/bf02845236] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Affiliation(s)
- A K Batta
- Department of Medicine, UMDNJ-NJ Medical School, Newark, USA
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36
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Changes in serum sterols of rats treated with 7-dehydrocholesterol-delta 7-reductase inhibitors: comparison to levels in humans with Smith-Lemli-Opitz syndrome. J Lipid Res 1996. [DOI: 10.1016/s0022-2275(20)39162-8] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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37
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Tint GS, Salen G, Batta AK, Shefer S, Irons M, Elias ER, Abuelo DN, Johnson VP, Lambert M, Lutz R. Correlation of severity and outcome with plasma sterol levels in variants of the Smith-Lemli-Opitz syndrome. J Pediatr 1995; 127:82-7. [PMID: 7608816 DOI: 10.1016/s0022-3476(95)70261-x] [Citation(s) in RCA: 123] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
OBJECTIVES To determine whether type I and the more severe type II variant of Smith-Lemli-Opitz syndrome have the same metabolic defect and to learn which plasma sterol measurements best predict survival. METHODS Plasma sterols were measured in 33 individuals (24 type I, 9 type II) with a clinical diagnosis of the syndrome. RESULTS Cholesterol levels were abnormally low (61 +/- 34 mg/dl) in type I subjects, whereas concentrations of the cholesterol precursor 7-dehydrocholesterol and its isomer 8-dehydrocholesterol were elevated 40- to 10,000-fold. Plasma cholesterol levels were significantly lower and total dehydrocholesterol levels higher in type II than in type I. Six children with the type II variant died by 13 weeks with mean plasma cholesterol levels 6.2 +/- 3.1 mg/dl, versus 17 +/- 11 mg/dl in the three surviving children with type II (p < 0.05). No child with a cholesterol level 7 mg/dl or less lived longer than 13 weeks. CONCLUSIONS Patients with type I and type II variants of Smith-Lemli-Opitz syndrome have markedly reduced activity of the enzyme that converts 7-dehydrocholesterol to cholesterol, but the extent of the block is far more complete in type II. Survival correlates strongly with higher plasma cholesterol concentrations.
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Affiliation(s)
- G S Tint
- Research Service, Department of Veterans Affairs Medical Center, East Orange, NJ 07018, USA
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38
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Batta AK, Tint GS, Shefer S, Abuelo D, Salen G. Identification of 8-dehydrocholesterol (cholesta-5,8-dien-3 beta-ol) in patients with Smith-Lemli-Opitz syndrome. J Lipid Res 1995. [DOI: 10.1016/s0022-2275(20)40056-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
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39
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Irons M, Elias ER, Tint GS, Salen G, Frieden R, Buie TM, Ampola M. Abnormal cholesterol metabolism in the Smith-Lemli-Opitz syndrome: report of clinical and biochemical findings in four patients and treatment in one patient. AMERICAN JOURNAL OF MEDICAL GENETICS 1994; 50:347-52. [PMID: 8209913 DOI: 10.1002/ajmg.1320500409] [Citation(s) in RCA: 84] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
We report on four patients with the Smith-Lemli-Opitz (SLO) syndrome who appear to have a defect in cholesterol biosynthesis. The initial results of therapy of one of the patients with cholesterol and bile acids to correct her metabolic abnormalities are described. This finding provides a biochemical marker to help in the diagnosis of this syndrome, may provide insight into the pathogenesis of this disorder, and have therapeutic and prenatal diagnostic implications as well.
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Affiliation(s)
- M Irons
- Department of Pediatrics, New England Medical Center, Tufts University School of Medicine, Boston, Massachusetts 02111
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40
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Tint GS, Irons M, Elias ER, Batta AK, Frieden R, Chen TS, Salen G. Defective cholesterol biosynthesis associated with the Smith-Lemli-Opitz syndrome. N Engl J Med 1994; 330:107-13. [PMID: 8259166 DOI: 10.1056/nejm199401133300205] [Citation(s) in RCA: 575] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
BACKGROUND The Smith-Lemli-Opitz syndrome (frequency, 1:20,000 to 1:40,000) is defined by a constellation of severe birth defects affecting most organ systems. Abnormalities frequently include profound mental retardation, severe failure to thrive, and a high infant-mortality rate. The syndrome has heretofore been diagnosed only from its clinical presentation. METHODS Using capillary-column gas chromatography-mass spectrometry, we measured the sterol composition of plasma, erythrocytes, lens, cultured fibroblasts, and feces from five children with the syndrome (three girls and two boys). RESULTS Plasma cholesterol levels were abnormally low (8 to 101 mg per deciliter [0.20 to 2.60 mmol per liter]) in every patient, being well below the 5th percentile for age- and sex-matched controls. Concentrations of the cholesterol precursor 7-dehydrocholesterol (cholesta-5,7-dien-3 beta-ol), which was not detectable in most of our controls, were elevated (11 to 31 mg per deciliter) more than 2000-fold above normal and were similar to the levels of cholesterol in all tissues from all patients. An isomeric dehydrocholesterol with a structure similar to that of 7-dehydrocholesterol was also detected. CONCLUSIONS The combination of abnormally low plasma cholesterol levels and a high concentration of the cholesterol precursor 7-dehydrocholesterol points to a major block in cholesterol biosynthesis at the step in which the C-7(8) double bond of 7-dehydrocholesterol is reduced, forming cholesterol. The block may be sufficient to deprive an embryo or fetus of cholesterol and prevent normal development, whereas the incorporation of 7-dehydrocholesterol into all membranes may interfere with proper membrane function.
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Affiliation(s)
- G S Tint
- Department of Medicine, Veteran Affairs Medical Center, East Orange, N.J. 07018-1095
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41
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Brewer LM, Sheardown SA, Brown NA. HMG-CoA reductase mRNA in the post-implantation rat embryo studied by in situ hybridization. TERATOLOGY 1993; 47:137-46. [PMID: 8446927 DOI: 10.1002/tera.1420470206] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
3-Hydroxy-3-methylglutaryl coenzyme A (HMG-CoA) reductase (EC 1.1.1.34) is the rate limiting step in the mevalonate pathway that produces isoprenoids and cholesterol. Inhibitors of HMG-CoA reductase are teratogenic in vivo and induce neural tube defects in rat embryo culture, effects which appear unrelated to cholesterol deficiency. This study is the first to localize HMG-CoA reductase mRNA by in situ hybridization (ISH). Expression of reductase mRNA was examined in post-implantation rat embryos, and for control purposes in rat liver and UT-1 cells, using a digoxigenin-11 (dig-11) labelled cRNA probe. Eighteen-day fetal liver showed heavy but patchy hybridization, and adult rat liver showed strong hybridization only on some periportal hepatocytes, which was absent in livers of fasted animals. UT-1 cells stimulated to overexpress HMG-CoA reductase mRNA were strongly positive with the same probe. Control hybridizations with sense strand RNA probe, or with cRNA probe on pre-RNased tissue were negative. Strong hybridization signal for HMG-CoA reductase mRNA was observed in all tissues of the post-implantation rat embryo, from egg cylinder to 30 somite stages (7 to 12 days). Heavy signal was noted in primitive ectoderm and neural tube. The wide embryonic and extraembryonic distribution and abundance of HMG-CoA reductase mRNA may reflect developmental requirements for products of the mevalonate pathway, e.g., isoprenoids for post-translational farnesylation of p21ras.
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Affiliation(s)
- L M Brewer
- MRC Experimental Embryology and Teratology Unit, St. George's Hospital, Medical School, London, United Kingdom
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