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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: 6] [Impact Index Per Article: 6.0] [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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Gul H, Chen X, Geng Z. Comparative Yolk Proteomic Analysis of Fertilized Low and High Cholesterol Eggs during Embryonic Development. Animals (Basel) 2021; 11:ani11030744. [PMID: 33803097 PMCID: PMC8035655 DOI: 10.3390/ani11030744] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Revised: 02/13/2021] [Accepted: 02/25/2021] [Indexed: 01/29/2023] Open
Abstract
Simple Summary Cholesterol exists in each cell of the living organism and plays a significant role in cellular functions. Several reports have demonstrated that high yolk cholesterol concentration affected embryo mortality, hatchability, and performance. The present results showed that high-cholesterol egg yolks had increased protein intensities and egg and yolk weight relative to low-cholesterol egg yolks. The differentially expressed yolk proteins were primarily involved in lipid transport, lipid localization, nutrient reservoir function, and embryo protection during embryonic development. Abstract The yolk is the principal part of the egg that contains vitamins, minerals, lipids, and proteins which are essential for embryo development and hatching. The egg yolk contains significant amounts of lipoproteins, triacylglycerides, and cholesterol, whose dynamics are indistinct during embryogenesis. The effects of cholesterol on the yolk protein abundance, intensity, and function are ill-defined during embryonic development. Using two-dimensional gel electrophoresis, eggs with respective high and low cholesterol protein abundance were investigated after 0, 2, 6, and 13 days of embryogenesis and further analyzed by matrix-assisted laser desorption/ionization time-of-flight tandem mass spectrometry. The results revealed that the vitellogenin proteins are the most abundant egg yolk protein that showed proximity and a high degree of variation in isoelectric point and molecular weight. The results demonstrated increased expression of vitellogenin-1 and vitellogenin-3 at two days and vitellogenin-2 protein at 13 days of embryogenesis in both egg types. The ovoinhibitor, immunoglobulin lambda light chain precursor, Ig-gamma (clone-36 chicken), and beta-2-glycoprotein-1 precursor proteins were significantly expressed in high cholesterol eggs while haptoglobin protein PIT-54 and vitelline membrane outer layer proteins intensities were significant in low cholesterol eggs at two days of embryogenesis. The high cholesterol eggs showed a modest increase in egg weight, yolk weight, albumen height, yolk color, and egg strength relative to the low cholesterol eggs. The gene ontology enrichment analysis revealed that the differentially expressed proteins such as vitellogenin proteins were involved in lipid transport and lipid localization biological processes and showed nutrient reservoir activity function. The ovotransferrin regulated the biological processes of plasminogen activation and extracellular matrix disassembly and characterized the anchored component of the plasma membrane. The ovoinhibitor protein was involved in response to mineralocorticoid and corticosterone biological processes whereas the vitellin membrane outer layer protein constituted the extracellular exosome, extracellular organelle, and membrane-bounded vesicle cellular components. Collectively, our study revealed yolk protein abundance, molecular function, cellular components, and biological processes and concluded that yolk protein intensities were significantly altered by cholesterol concentration.
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Affiliation(s)
- Haji Gul
- College of Animal Science and Technology, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei 230036, China;
- Anhui Province Key Laboratory of Local Livestock and Poultry Genetic Resource Conservation and Bio-Breeding, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei 230036, China
- Correspondence: (H.G.); (Z.G.)
| | - Xingyong Chen
- College of Animal Science and Technology, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei 230036, China;
- Anhui Province Key Laboratory of Local Livestock and Poultry Genetic Resource Conservation and Bio-Breeding, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei 230036, China
| | - Zhaoyu Geng
- College of Animal Science and Technology, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei 230036, China;
- Anhui Province Key Laboratory of Local Livestock and Poultry Genetic Resource Conservation and Bio-Breeding, Anhui Agricultural University, No. 130 Changjiang West Road, Hefei 230036, China
- Correspondence: (H.G.); (Z.G.)
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Temple SEL, Sachdev R, Ellaway C. Familial DHCR7 genotype presenting as a very mild form of Smith-Lemli-Opitz syndrome and lethal holoprosencephaly. JIMD Rep 2020; 56:3-8. [PMID: 33204589 PMCID: PMC7653247 DOI: 10.1002/jmd2.12155] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/26/2020] [Revised: 07/15/2020] [Accepted: 07/17/2020] [Indexed: 11/09/2022] Open
Abstract
Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive metabolic disorder caused by variants in the DHCR7 gene. In cholesterol biosynthesis, 7-dehydrocholesterol (7-DHC) is converted to cholesterol by the enzyme 7-DHC reductase, which is encoded by the gene DHCR7. Thus, an elevated 7-DHC is indicative of SLOS. Characteristically SLOS is usually associated with congenital anomalies, dysmorphisms, and moderate to severe neurodevelopmental delay. However, there are rare descriptions of individuals with milder phenotypes. We report a mild case of SLOS presenting with short stature, cleft palate, imperforate anus, and mild language delay with subtle dysmorphic features. 7-DHC was not elevated at 1 year of age and SLOS considered excluded at this time. The parents had two pregnancies with holoprosencephaly. Whole exome sequencing of one of the fetuses identified compound heterozygous pathogenic variants in the DHCR7 gene (c.964-1G>C (p.?) and c.1039G>A (p.Gly347Ser) causative of SLOS. The proband with a mild form of SLOS was also found to have the same DHCR7 variants as the fetus and repeat testing of 7-DHC at 4 years of age was elevated, in keeping with SLOS. This case is the first to describe a wide intrafamilial phenotypic spectrum of SLOS as a result of the same DHCR7 genotype. This case also supports the findings of others that a normal or near normal development should not exclude SLOS. As demonstrated in this case exclusion of a metabolic diagnosis because of a negative biochemical marker such as 7-DHC is not absolute and if clinical suspicion remains genomic sequencing is warranted.
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Affiliation(s)
- Suzanna E. L. Temple
- Centre for Clinical GeneticsSydney Children's HospitalRandwickNew South WalesAustralia
| | - Rani Sachdev
- Centre for Clinical GeneticsSydney Children's HospitalRandwickNew South WalesAustralia
| | - Carolyn Ellaway
- Centre for Clinical GeneticsSydney Children's HospitalRandwickNew South WalesAustralia
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4
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Disruption of Dhcr7 and Insig1/2 in cholesterol metabolism causes defects in bone formation and homeostasis through primary cilium formation. Bone Res 2020; 8:1. [PMID: 31934493 PMCID: PMC6946666 DOI: 10.1038/s41413-019-0078-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2019] [Revised: 08/20/2019] [Accepted: 08/26/2019] [Indexed: 02/07/2023] Open
Abstract
Human linkage studies suggest that craniofacial deformities result from either genetic mutations related to cholesterol metabolism or high-cholesterol maternal diets. However, little is known about the precise roles of intracellular cholesterol metabolism in the development of craniofacial bones, the majority of which are formed through intramembranous ossification. Here, we show that an altered cholesterol metabolic status results in abnormal osteogenesis through dysregulation of primary cilium formation during bone formation. We found that cholesterol metabolic aberrations, induced through disruption of either Dhcr7 (which encodes an enzyme involved in cholesterol synthesis) or Insig1 and Insig2 (which provide a negative feedback mechanism for cholesterol biosynthesis), result in osteoblast differentiation abnormalities. Notably, the primary cilia responsible for sensing extracellular cues were altered in number and length through dysregulated ciliary vesicle fusion in Dhcr7 and Insig1/2 mutant osteoblasts. As a consequence, WNT/β-catenin and hedgehog signaling activities were altered through dysregulated primary cilium formation. Strikingly, the normalization of defective cholesterol metabolism by simvastatin, a drug used in the treatment of cholesterol metabolic aberrations, rescued the abnormalities in both ciliogenesis and osteogenesis in vitro and in vivo. Thus, our results indicate that proper intracellular cholesterol status is crucial for primary cilium formation during skull formation and homeostasis.
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Domizio S, Pallotta R, Romanelli A, Puglielli C, Pollice R, Casacchia M, Conte E, Domizio R, Sabatino G. A Case of Smith-Lemli-Opitz Syndrome, Defect of Cholesterol Biosynthesis. Int J Immunopathol Pharmacol 2016; 19:439-42. [PMID: 16831310 DOI: 10.1177/039463200601900220] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Abstract
We report the case of a child with Smith-Lemli-Opitz Syndrome. The pregnancy was complicated by prenatal growth retardation. The baby was admitted to the Neonatal Intensive Care Unit of Chieti when she was five months old. She showed postnatal growth retardation, trouble sucking and swallowing, microcefaly and multiple major and minor malformations, including characteristic facial features and 2–3 syndactyly of the toes. We found correlations between multiple congenital malformations, failure to thrive and low plasmatic cholesterol measurement.
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Affiliation(s)
- S Domizio
- Neonatal Intensive Care Unit, University G. D'Annunzio, Ospedale Policlinico, Via dei Vestini 5, 66100 Chieti, Italy
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Abstract
Neonatologists have a unique opportunity to be the first to identify abnormalities in a neonate. In this review, multiple anomalies and physical features are discussed along with the potential associated genetic syndromes. The anomalies and physical features that are discussed include birth parameters, aplasia cutis congenita, holoprosencephaly, asymmetric crying facies, preauricular ear tags and pits, cleft lip with or without cleft palate, esophageal atresia/tracheoesophageal fistula, congenital heart defects, ventral wall defects, and polydactyly.
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Affiliation(s)
| | - Margaret P. Adam
- CORRESPONDING AUTHOR: Margaret P. Adam, MD, Professor of Pediatrics, Division of Genetic Medicine, 4800 Sand Point Way NE, PO Box 5371/OC.9.850, Seattle, WA 98105, , ph: 206-987-2689, fax: 206-987-2495, Kelly Jones, MD, 4800 Sand Point Way NE, OC.9.850, Seattle, WA 98105, , ph: 206-987-7119
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Platt FM, Wassif C, Colaco A, Dardis A, Lloyd-Evans E, Bembi B, Porter FD. Disorders of cholesterol metabolism and their unanticipated convergent mechanisms of disease. Annu Rev Genomics Hum Genet 2015; 15:173-94. [PMID: 25184529 DOI: 10.1146/annurev-genom-091212-153412] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
Cholesterol plays a key role in many cellular processes, and is generated by cells through de novo biosynthesis or acquired from exogenous sources through the uptake of low-density lipoproteins. Cholesterol biosynthesis is a complex, multienzyme-catalyzed pathway involving a series of sequentially acting enzymes. Inherited defects in genes encoding cholesterol biosynthetic enzymes or other regulators of cholesterol homeostasis result in severe metabolic diseases, many of which are rare in the general population and currently without effective therapy. Historically, these diseases have been viewed as discrete disorders, each with its own genetic cause and distinct pathogenic cascades that lead to its specific clinical features. However, studies have recently shown that three of these diseases have an unanticipated mechanistic convergence. This surprising finding is not only shedding light on details of cellular cholesterol homeostasis but also suggesting novel approaches to therapy.
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Affiliation(s)
- Frances M Platt
- Department of Pharmacology, University of Oxford, Oxford OX1 3QT, United Kingdom;
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Svoboda MD, Christie JM, Eroglu Y, Freeman KA, Steiner RD. Treatment of Smith-Lemli-Opitz syndrome and other sterol disorders. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2012; 160C:285-94. [PMID: 23042642 DOI: 10.1002/ajmg.c.31347] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive genetic condition with a broad phenotype that results from deficiency of the final enzyme of the cholesterol synthesis pathway. This defect causes low or low-normal plasma cholesterol levels and increased 7- and 8-dehydrocholesterol (DHC) levels. Many therapies for SLOS and other disorders of sterol metabolism have been proposed, and a few of them have been undertaken in selected patients, but robust prospective clinical trials with validated outcome measures are lacking. We review the current literature and expert opinion on treatments for SLOS and other selected sterol disorders, including dietary cholesterol therapy, statin treatment, bile acid supplementation, medical therapies, and surgical interventions, as well as directions for future therapies and treatment research.
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Affiliation(s)
- Melissa D Svoboda
- Oregon Health&Science University (OHSU), Portland, Oregon 97239, USA
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Roullet JB, Merkens LS, Pappu AS, Jacobs MD, Winter R, Connor WE, Steiner RD. No evidence for mevalonate shunting in moderately affected children with Smith-Lemli-Opitz syndrome. J Inherit Metab Dis 2012; 35:859-69. [PMID: 22391996 PMCID: PMC3404269 DOI: 10.1007/s10545-012-9453-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2011] [Revised: 12/29/2011] [Accepted: 01/10/2012] [Indexed: 10/28/2022]
Abstract
Smith-Lemli-Opitz syndrome (SLOS) is caused by a genetic deficiency in 7-dehydrocholesterol (7-DHC) reductase (EC 1.3.1.21), the last enzyme of the cholesterol synthetic pathway. In SLOS, plasma cholesterol concentration is reduced and immediate precursor concentration (7-DHC) is elevated. Surprisingly, total sterol synthesis is reduced but HMG-CoA reductase activity, a rate-limiting enzyme in cholesterol synthesis is unaltered as judged by normal urinary excretion of mevalonic acid (MVA) (Pappu et al. J Lipid Res 43:1661-1669, 2002). These findings raise the possibility of increased diversion of MVA into the MVA shunt pathway away from sterol synthesis, by activation of the shunt pathway enzymes. To test this hypothesis, we measured the urinary excretion of 3-methylglutaconic acid (U-3MGC), a by-product of the shunt pathway, in 19 mildly to moderately severely affected SLOS subjects (ten males, nine females) receiving either a cholesterol-free or a high cholesterol diet, and in 20 age- and sex-matched controls. U-3MGC was similar in SLOS and controls, and was unaffected by dietary cholesterol intake. Further, no change in U-3MGC was observed in a subset of SLOS subjects (n = 9) receiving simvastatin. In contrast, U-MVA was reduced by cholesterol supplementation (~54%, p < 0.05) and by simvastatin (~50%, p < 0.04). There was no correlation between U-3MGC and either plasma sterol concentrations, urinary isoprenoids, or the subjects' clinical severity score. However U-3MGC was inversely correlated with age (p < 0.04) and body weight (p < 0.02), and higher in females than in males (~65%, p < 0.025). The data show that DHCR7 deficiency does not result in 3MGC accumulation in SLOS and suggest that the MVA shunt pathway is not activated in patients with the condition.
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Affiliation(s)
- Jean-Baptiste Roullet
- Department of Pediatrics, Oregon Health & Science University, 707 S.W. Gaines St., Portland, OR 97239-2998, USA.
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Gründahl J, Guan Z, Rust S, Reunert J, Müller B, Du Chesne I, Zerres K, Rudnik-Schöneborn S, Ortiz-Brüchle N, Häusler M, Siedlecka J, Swiezewska E, Raetz C, Marquardt T. Life with too much polyprenol: polyprenol reductase deficiency. Mol Genet Metab 2012; 105:642-51. [PMID: 22304929 PMCID: PMC3428379 DOI: 10.1016/j.ymgme.2011.12.017] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/05/2011] [Revised: 12/20/2011] [Accepted: 12/20/2011] [Indexed: 11/27/2022]
Abstract
Congenital disorders of glycosylation (CDG) are caused by a dysfunction of glycosylation, an essential step in the manufacturing process of glycoproteins. This paper focuses on a 6-year-old patient with a new type of CDG-I caused by a defect of the steroid 5α reductase type 3 gene (SRD5A3). The clinical features were psychomotor retardation, pathological nystagmus, slight muscular hypotonia and microcephaly. SRD5A3 was recently identified encoding the polyprenol reductase, an enzyme catalyzing the final step of the biosynthesis of dolichol, which is required for the assembly of the glycans needed for N-glycosylation. Although an early homozygous stop-codon (c.57G>A [W19X]) with no functional protein was found in the patient, about 70% of transferrin (Tf) was correctly glycosylated. Quantification of dolichol and unreduced polyprenol in the patient's fibroblasts demonstrated a high polyprenol/dolichol ratio with normal amounts of dolichol, indicating that high polyprenol levels might compete with dolichol for the initiation of N-glycan assembly but without supporting normal glycosylation and that there must be an alternative pathway for dolichol biosynthesis.
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Affiliation(s)
- J.E.H. Gründahl
- Universitätsklinikum Münster, Klinik und Poliklinik für Kinder- und Jugendmedizin—Allgemeine Pädiatrie, Münster, Germany
| | - Z. Guan
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - S. Rust
- Leibniz-Institut für Arterioskleroseforschung, Münster, Germany
| | - J. Reunert
- Universitätsklinikum Münster, Klinik und Poliklinik für Kinder- und Jugendmedizin—Allgemeine Pädiatrie, Münster, Germany
| | - B. Müller
- Department of Pediatrics, University Hospital RWTH Aachen, Germany
| | - I. Du Chesne
- Universitätsklinikum Münster, Klinik und Poliklinik für Kinder- und Jugendmedizin—Allgemeine Pädiatrie, Münster, Germany
| | - K. Zerres
- Institute of Human Genetics, University Hospital RWTH Aachen, Germany
| | | | - N. Ortiz-Brüchle
- Institute of Human Genetics, University Hospital RWTH Aachen, Germany
| | - M.G. Häusler
- Department of Pediatrics, University Hospital RWTH Aachen, Germany
| | - J. Siedlecka
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - E. Swiezewska
- Institute of Biochemistry and Biophysics, Polish Academy of Sciences, Warsaw, Poland
| | - C.R.H. Raetz
- Department of Biochemistry, Duke University Medical Center, Durham, NC, USA
| | - T. Marquardt
- Universitätsklinikum Münster, Klinik und Poliklinik für Kinder- und Jugendmedizin—Allgemeine Pädiatrie, Münster, Germany
- Corresponding author at: Klinik für Kinder- und Jugendmedizin, Albert-Schweitzer-Str. 33, 48149 Münster, Germany. Fax: +49 251 835 6085. (T. Marquardt)
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Leiva A, Pardo F, Ramírez MA, Farías M, Casanello P, Sobrevia L. Fetoplacental vascular endothelial dysfunction as an early phenomenon in the programming of human adult diseases in subjects born from gestational diabetes mellitus or obesity in pregnancy. EXPERIMENTAL DIABETES RESEARCH 2011; 2011:349286. [PMID: 22144986 PMCID: PMC3226353 DOI: 10.1155/2011/349286] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/16/2011] [Revised: 08/11/2011] [Accepted: 09/07/2011] [Indexed: 12/16/2022]
Abstract
Gestational diabetes mellitus (GDM) and obesity in pregnancy (OP) are pathological conditions associated with placenta vascular dysfunction coursing with metabolic changes at the fetoplacental microvascular and macrovascular endothelium. These alterations are seen as abnormal expression and activity of the cationic amino acid transporters and endothelial nitric oxide synthase isoform, that is, the "endothelial L-arginine/nitric oxide signalling pathway." Several studies suggest that the endogenous nucleoside adenosine along with insulin, and potentially arginases, are factors involved in GDM-, but much less information regards their role in OP-associated placental vascular alterations. There is convincing evidence that GDM and OP prone placental endothelium to an "altered metabolic state" leading to fetal programming evidenced at birth, a phenomenon associated with future development of chronic diseases. In this paper it is suggested that this pathological state could be considered as a metabolic marker that could predict occurrence of diseases in adulthood, such as cardiovascular disease, obesity, diabetes mellitus (including gestational diabetes), and metabolic syndrome.
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Affiliation(s)
- Andrea Leiva
- Cellular and Molecular Physiology Laboratory (CMPL), Division of Obstetrics and Gynaecology, School of Medicine, Faculty of Medicine, Pontificia Universidad Catolica de Chile, P.O. Box 114-D, Santiago, Chile
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Liu Y, Chipot C, Shao X, Cai W. The effects of 7-dehydrocholesterol on the structural properties of membranes. Phys Biol 2011; 8:056005. [DOI: 10.1088/1478-3975/8/5/056005] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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13
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Rebholz SL, Burke KT, Yang Q, Tso P, Woollett LA. Dietary fat impacts fetal growth and metabolism: uptake of chylomicron remnant core lipids by the placenta. Am J Physiol Endocrinol Metab 2011; 301:E416-25. [PMID: 21586694 PMCID: PMC3154537 DOI: 10.1152/ajpendo.00619.2010] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
The fetus requires significant energy for growth and development. Although glucose is a major source of energy for the fetus, other maternal nutrients also appear to promote growth. Thus, the goal of these studies was to determine whether triglyceride-rich remnants are taken up by the placenta and whether maternal dietary lipids, independently of adiposity, can impact fetal growth. To accomplish our first goal, chylomicron particles were duallly labeled with cholesteryl ester and triglycerides. The placenta took up remnant particles/core lipids at rates greater than adipose tissue and skeletal muscle but less than the liver. Although the placenta expresses apoE receptors, uptake of chylomicron remnants and/or core lipids can occur independently of apoE. To determine the impact of dietary lipid on fetal growth, independent of maternal adiposity, females were fed high-fat diets (HFD) for 1 mo; there was no change in adiposity or leptin levels prior to or during pregnancy of dams fed HFD. Fetal masses were greater in dams fed HFD, and mRNA levels of proteins involved in fatty acid oxidation (CPT I, PPARα), but not glucose oxidation (pyruvate kinase) or other regulatory processes (HNF-4α, LXR), were increased with maternal dietary fat. There was also no change in mRNA levels of proteins involved in placental glucose and fatty acid transport, and GLUT1 protein levels in microvillous membranes were similar in placentas of dams fed either diet. Thus, the ability of the placenta to take up chylomicron remnant core lipids likely contributes to accelerated fetal growth in females fed high fat diets.
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Affiliation(s)
- Sandra L Rebholz
- Department of Pathology and Laboratory Medicine, University of Cincinnati Medical School, 2180 E. Galbraith Rd., Cincinnati, OH 45237, USA
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Abstract
Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive, multiple congenital malformation and intellectual disability syndrome, with clinical characteristics that encompass a wide spectrum and great variability. Elucidation of the biochemical and genetic basis for SLOS, specifically understanding SLOS as a cholesterol deficiency syndrome caused by mutation in DHCR7, opened up enormous possibilities for therapeutic intervention. When cholesterol was discovered to be the activator of sonic hedgehog, cholesterol deficiency with inactivation of this developmental patterning gene was thought to be the cause of SLOS malformations, yet this explanation is overly simplistic. Despite these important research breakthroughs, there is no proven treatment for SLOS. Better animal models are needed to allow potential treatment testing and the study of disease pathophysiology, which is incompletely understood. Creation of human cellular models, especially models of brain cells, would be useful, and in vivo human studies are also essential. Biomarker development will be crucial in facilitating clinical trials in this rare condition, because the clinical phenotype can change over many years. Additional research in these and other areas is critical if we are to make headway towards ameliorating the effects of this devastating condition.
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Zarowski M, Vendrame M, Irons M, Kothare SV. Prevalence of sleep problems in Smith-Lemli-Opitz syndrome. Am J Med Genet A 2011; 155A:1558-62. [DOI: 10.1002/ajmg.a.34021] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2011] [Accepted: 03/10/2011] [Indexed: 11/08/2022]
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Chan YM, Merkens LS, Connor WE, Roullet JB, Penfield JA, Jordan JM, Steiner RD, Jones PJH. Effects of dietary cholesterol and simvastatin on cholesterol synthesis in Smith-Lemli-Opitz syndrome. Pediatr Res 2009; 65:681-5. [PMID: 19430384 PMCID: PMC2780332 DOI: 10.1203/pdr.0b013e31819ea4eb] [Citation(s) in RCA: 33] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Deficient cholesterol and/or excessive 7-dehydrocholesterol (7-DHC) may be responsible for the pathology of Smith-Lemli-Opitz syndrome (SLOS). Both high-cholesterol diets given to ameliorate cholesterol deficiency while decreasing 7-DHC and cholesterol-enriched diets plus simvastatin to further decrease sterol synthesis have been used as potential therapies. However, the effect of dietary cholesterol and simvastatin on cholesterol synthesis in SLOS has not been reported. Twelve subjects with SLOS enrolled in the study: Nine had received a high cholesterol diet (HI) for 3 y and three were studied after 4 wk on a low cholesterol diet (LO). Cholesterol fractional synthesis rate (FSR) was measured after oral administration of deuterium oxide, using gas chromatography isotope ratio mass spectrometry. FSR was lower in HI compared with LO (HI: 1.46 +/- 0.62%/d; LO: 4.77 +/- 0.95%/d; p < 0.001). Three HI subjects were retested after 0.8 y taking simvastatin (HI + ST). Simvastatin tended to reduce FSR and significantly decreased (p < 0.01) plasma 7-DHC compared with cholesterol supplementation alone. The study demonstrates the utility of the deuterium incorporation method to understand the effect of therapeutic interventions in SLOS. The data suggest that dietary cholesterol supplementation reduces cholesterol synthesis in SLOS and further support the rationale for the combined treatment of SLOS with a cholesterol-enriched diet and simvastatin.
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Affiliation(s)
- Yen-Ming Chan
- Richardson Centre for Functional Foods and Nutraceuticals, University of Manitoba, Winnipeg, Manitoba, Canada
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Merkens LS, Jordan JM, Penfield JA, Lütjohann D, Connor WE, Steiner RD. Plasma plant sterol levels do not reflect cholesterol absorption in children with Smith-Lemli-Opitz syndrome. J Pediatr 2009; 154:557-561.e1. [PMID: 19101685 PMCID: PMC3092779 DOI: 10.1016/j.jpeds.2008.10.045] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2008] [Revised: 09/11/2008] [Accepted: 10/31/2008] [Indexed: 02/02/2023]
Abstract
OBJECTIVE To test the hypothesis that there is a correlation between the ratio of plant sterols to cholesterol in plasma and dietary cholesterol absorption in children with Smith-Lemli-Opitz syndrome (SLOS), a cholesterol synthesis disorder. STUDY DESIGN We obtained measurements of cholesterol absorption with a direct radioisotope cholesterol absorption method during 9 visits of children with SLOS. We measured plasma sterols in 22 children with SLOS and 16 control children, and we measured dietary intake of cholesterol and sitosterol (n=11 SLOS). RESULTS The correlations of 2 plasma plant sterol ratios (sitosterol/cholesterol and campesterol/cholesterol) with direct cholesterol absorption measurement were poor (R= -0.33 and R= -0.25, respectively), significantly lower than the published correlation in adults (R=0.73; P< .02). CONCLUSIONS Although the ratios of plant sterols to cholesterol in plasma has been used as a surrogate for cholesterol absorption in adults and children, these ratios may not accurately reflect cholesterol absorption in children with SLOS. These ratios should not be used as a surrogate for cholesterol absorption in children without further validation.
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Affiliation(s)
- Louise S. Merkens
- Department of Pediatrics, Oregon Health & Science University, Portland, OR
| | - Julia M. Jordan
- Oregon Clinical and Translation Research Institute, Oregon Health & Science University, Portland, OR
| | | | - Dieter Lütjohann
- Department of Clinical Pharmacology, University of Bonn, Bonn, Germany
| | - William E. Connor
- Oregon Clinical and Translation Research Institute, Oregon Health & Science University, Portland, OR
| | - Robert D. Steiner
- Department of Pediatrics, Oregon Health & Science University, Portland, OR,Department of Molecular and Medical Genetics and Oregon Clinical and Translational Research Institute, Child Development and Rehabilitation Center, Doernbecher Children's Hospital, Oregon Health & Science University, Portland, OR
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Abstract
The development of a single-celled fertilized egg, through the blastocyst stage of a ball of cells and the embryonic stage when almost all organ systems begin to develop, and finally to the fetal stage where growth and physiological maturation occurs, is a complex and multifaceted process. A change in metabolism during gestation, especially when organogenesis occurs, can lead to abnormal development and congenital defects. Although many studies have described the roles of specific proteins in development, the roles of specific lipids, such as sterols, have not been studied as intensely. Sterol's functions in development range from being a structural component of membranes to regulating the patterning of the forebrain through sonic hedgehog to regulating expression of key proteins involved in metabolic processes. This review focuses on the roles of sterols in embryonic and fetal development and metabolism. Potential sources of cholesterol for the fetus and embryo are also discussed.
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Affiliation(s)
- Laura A Woollett
- Department of Pathology and Laboratory Medicine, University of Cincinnati, Cincinnati, Ohio 45237, USA.
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Paila YD, Murty MR, Vairamani M, Chattopadhyay A. Signaling by the human serotonin1A receptor is impaired in cellular model of Smith–Lemli–Opitz Syndrome. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2008; 1778:1508-16. [DOI: 10.1016/j.bbamem.2008.03.002] [Citation(s) in RCA: 66] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/28/2008] [Revised: 03/01/2008] [Accepted: 03/05/2008] [Indexed: 10/22/2022]
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Jenkins KT, Merkens LS, Tubb MR, Myatt L, Davidson WS, Steiner RD, Woollett LA. Enhanced placental cholesterol efflux by fetal HDL in Smith-Lemli-Opitz syndrome. Mol Genet Metab 2008; 94:240-7. [PMID: 18346920 PMCID: PMC3037116 DOI: 10.1016/j.ymgme.2008.01.015] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/29/2008] [Accepted: 01/30/2008] [Indexed: 11/23/2022]
Abstract
Previous studies from this laboratory have shown that maternal-derived cholesterol can be effluxed from trophoblasts to fetal HDL and plasma. We had the opportunity to study for the first time the ability of HDL and plasma from a fetus with the Smith-Lemli-Opitz syndrome (SLOS) to efflux cholesterol from trophoblasts. It was unclear whether cholesterol could be effluxed to fetuses with SLOS since lipoprotein levels are often very low. To answer this question, cord blood was collected from the placentas of an SLOS fetus and unaffected fetuses just after delivery. Plasma cholesterol concentrations were very low in the affected fetus; cholesterol, 7-dehydrocholesterol, and 8-dehydocholesterol concentrations were 14.1, 4.5, and 5.2 mg/dl, respectively. The HDL from the fetal SLOS effluxed approximately 50% more cholesterol from a trophoblast cell line, were smaller in size, and had a lower cholesterol to phospholipid ratio as compared to HDL from unaffected fetuses or adults. Plasma from the SLOS fetus effluxed cholesterol to a similar percentage as unaffected fetal plasma or adult plasma, possibly due to fewer HDL particles as demonstrated in previous SLOS patients. These novel data demonstrate that the cholesterol-deficient SLOS fetus is able to obtain cholesterol from trophoblasts at a time when cholesterol is playing a critical role in development, and has implications for design of treatments for cholesterol deficiency syndromes as well as understanding of prenatal cholesterol transport in humans.
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Affiliation(s)
- Katie T. Jenkins
- Departments of Pathology and Laboratory Medicine, Genome Research Institute, University of Cincinnati Medical School, 2180 E. Galbraith Road, Cincinnati, OH 45237-0507, USA
| | - Louise S. Merkens
- Department of Pediatrics, Oregon Health & Science University, Portland, OR, USA
| | - Matthew R. Tubb
- Departments of Pathology and Laboratory Medicine, Genome Research Institute, University of Cincinnati Medical School, 2180 E. Galbraith Road, Cincinnati, OH 45237-0507, USA
| | - Leslie Myatt
- Departments of Obstetrics and Gynecology, Genome Research Institute, University of Cincinnati Medical School, 2180 E. Galbraith Road, Cincinnati, OH 45237-0507, USA
| | - W. Sean Davidson
- Departments of Pathology and Laboratory Medicine, Genome Research Institute, University of Cincinnati Medical School, 2180 E. Galbraith Road, Cincinnati, OH 45237-0507, USA
| | - Robert D. Steiner
- Department of Pediatrics, Oregon Health & Science University, Portland, OR, USA
- Departments of Molecular and Medical Genetics, Child Development and Rehabilitation Center, Doernbecher Children’s Hospital and Oregon Clinical and Translational Research Institute, Oregon Health & Science University, Portland, OR, USA
| | - Laura A. Woollett
- Departments of Pathology and Laboratory Medicine, Genome Research Institute, University of Cincinnati Medical School, 2180 E. Galbraith Road, Cincinnati, OH 45237-0507, USA
- Corresponding author. Fax: +1 513 558 1312. (L.A. Woollett)
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22
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Valenza M, Cattaneo E. Cholesterol dysfunction in neurodegenerative diseases: Is Huntington's disease in the list? Prog Neurobiol 2006; 80:165-76. [PMID: 17067733 DOI: 10.1016/j.pneurobio.2006.09.005] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2006] [Revised: 09/22/2006] [Accepted: 09/26/2006] [Indexed: 11/18/2022]
Abstract
Brain cholesterol is an essential component of cell membranes, and involved in a number of biological functions such as membrane trafficking, signal transduction, myelin formation and synaptogenesis. Given these widespread activities and the knowledge that all brain cholesterol derives from local synthesis, it is not surprising that dysfunctions in cholesterol synthesis, storage, transport and removal may lead to human brain diseases. Some of these diseases emerge as a consequence of genetic defects in the enzymes involved in cholesterol biosynthesis; in other cases, such as Alzheimer's disease, there is a link between cholesterol metabolism and the formation and deposition of amyloid-beta peptide. Emerging evidence indicates that changes in cholesterol synthesis may also occur in Huntington's disease, an inherited, autosomal dominant neurodegenerative disorder that primarily affects striatal neurons of the brain. We here provide an overview of the involvement of cholesterol in normal brain function and its impact on neurodegenerative diseases. In particular, we consider the available clinical, biological and molecular evidence indicating a potential dysregulation of cholesterol homeostasis in Huntington's disease.
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Affiliation(s)
- Marta Valenza
- Department of Pharmacological Sciences and Centre for Stem Cell Research, Via Balzaretti 9, 20133 Milano, Italy
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23
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Pappu AS, Connor WE, Merkens LS, Jordan JM, Penfield JA, Illingworth DR, Steiner RD. Increased nonsterol isoprenoids, dolichol and ubiquinone, in the Smith-Lemli-Opitz syndrome: effects of dietary cholesterol. J Lipid Res 2006; 47:2789-98. [PMID: 16983147 DOI: 10.1194/jlr.m600295-jlr200] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
Smith-Lemli-Opitz syndrome (SLOS) is an inherited autosomal recessive cholesterol deficiency disorder. Our studies have shown that in SLOS children, urinary mevalonate excretion is normal and reflects hepatic HMG-CoA reductase activity but not ultimate sterol synthesis. Hence, we hypothesized that in SLOS there may be increased diversion of mevalonate to nonsterol isoprenoid synthesis. To test our hypothesis, we measured urinary dolichol and ubiquinone, two nonsterol isoprenoids, in 16 children with SLOS and 15 controls, all fed a low-cholesterol diet. The urinary excretion of both dolichol (P < 0.002) and ubiquinone (P < 0.02) in SLOS children was 7-fold higher than in control children, whereas mevalonate excretion was comparable. In a subset of 12 SLOS children, a high-cholesterol diet decreased urinary mevalonate excretion by 61% (P < 0.001), dolichol by 70% (P < 0.001), and ubiquinone by 67% (P < 0.03). Our hypothesis that in SLOS children, normal urinary mevalonate excretion results from increased diversion of mevalonate into the production of nonsterol isoprenoids is supported. Dietary cholesterol supplementation reduced urinary mevalonate and nonsterol isoprenoid excretion but did not change the relative ratios of their excretion. Therefore, in SLOS, a secondary peripheral regulation of isoprenoid synthesis may be stimulated.
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Affiliation(s)
- Anuradha S Pappu
- Division of Endocrinology, Diabetes, and Clinical Nutrition, Department of Medicine, Oregon Health and Science University, Portland, OR 97239, USA.
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24
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Valenza M, Rigamonti D, Goffredo D, Zuccato C, Fenu S, Jamot L, Strand A, Tarditi A, Woodman B, Racchi M, Mariotti C, Di Donato S, Corsini A, Bates G, Pruss R, Olson JM, Sipione S, Tartari M, Cattaneo E. Dysfunction of the cholesterol biosynthetic pathway in Huntington's disease. J Neurosci 2006; 25:9932-9. [PMID: 16251441 PMCID: PMC6725556 DOI: 10.1523/jneurosci.3355-05.2005] [Citation(s) in RCA: 202] [Impact Index Per Article: 11.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023] Open
Abstract
The expansion of a polyglutamine tract in the ubiquitously expressed huntingtin protein causes Huntington's disease (HD), a dominantly inherited neurodegenerative disease. We show that the activity of the cholesterol biosynthetic pathway is altered in HD. In particular, the transcription of key genes of the cholesterol biosynthetic pathway is severely affected in vivo in brain tissue from HD mice and in human postmortem striatal and cortical tissue; this molecular dysfunction is biologically relevant because cholesterol biosynthesis is reduced in cultured human HD cells, and total cholesterol mass is significantly decreased in the CNS of HD mice and in brain-derived ST14A cells in which the expression of mutant huntingtin has been turned on. The transcription of the genes of the cholesterol biosynthetic pathway is regulated via the activity of sterol regulatory element-binding proteins (SREBPs), and we found an approximately 50% reduction in the amount of the active nuclear form of SREBP in HD cells and mouse brain tissue. As a consequence, mutant huntingtin reduces the transactivation of an SRE-luciferase construct even under conditions of SREBP overexpression or in the presence of an exogenous N-terminal active form of SREBP. Finally, the addition of exogenous cholesterol to striatal neurons expressing mutant huntingtin prevents their death in a dose-dependent manner. We conclude that the cholesterol biosynthetic pathway is impaired in HD cells, mice, and human subjects, and that the search for HD therapies should also consider cholesterol levels as both a potential target and disease biomarker.
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Affiliation(s)
- Marta Valenza
- Department of Pharmacological Sciences, Center of Excellence on Neurodegenerative Diseases, University of Milan, 20133 Milan, Italy
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25
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Vaughan DK, Peachey NS, Richards MJ, Buchan B, Fliesler SJ. Light-induced exacerbation of retinal degeneration in a rat model of Smith-Lemli-Opitz syndrome. Exp Eye Res 2005; 82:496-504. [PMID: 16360150 PMCID: PMC2844790 DOI: 10.1016/j.exer.2005.08.008] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2005] [Revised: 08/04/2005] [Accepted: 08/10/2005] [Indexed: 11/18/2022]
Abstract
Potentiation of retinal degeneration by intense light exposure, and its amelioration by an antioxidant, were studied in a rat model of Smith-Lemli-Opitz syndrome (SLOS), in comparison with normal (control) Sprague-Dawley rats. The SLOS model is created by treating rats with AY9944, a selective inhibitor of cholesterol synthesis at the level of 3beta-hydroxysterol-Delta7-reductase. A subset of rats was treated with dimethylthiourea (DMTU), a synthetic antioxidant, 24 and 1 hr prior to light exposure. Half of the animals (+/-DMTU) were exposed to intense, constant, green light (24hr, 1700lx, 490-580 nm), while the others were maintained in darkness. Subsequently all animals were returned to dim cyclic light (20-40 lx, 12 hr light-12 hr dark) for 2 weeks, after which electroretinograms were recorded. One eye from each rat was taken for histological and quantitative morphometric analyses; sterol analysis was performed on retinas from contralateral eyes. HPLC analysis confirmed the accumulation of 7-dehydrocholesterol (7DHC) in retinas of AY9944-treated rats; cholesterol represented >99% of the sterol in control retinas. Histology of retinas from unexposed, AY9944-treated rats (6-week-old) was normal. In contrast, age-matched, light-exposed rats exhibited massive photoreceptor cell loss in both the superior and inferior hemispheres, and concomitant rod and cone dysfunction. The severity and geographic extent of the damage was far greater than that observed in normal albino rats exposed to the same conditions. DMTU pre-treatment largely prevented these degenerative changes. These findings indicate that the AY9944-induced rat SLOS model is hypersensitive to intense light-induced retinal damage, relative to normal rats. DMTU protection against light-induced damage implicates free radical-based oxidation in the retinal degeneration process. Furthermore, the use of green light (corresponding to the absorption maxima of rhodopsin) implicates rhodopsin in the initiation of the pathobiological mechanism. We propose that generation of cytotoxic oxysterols (by-products of 7DHC oxidation) is an integral part of retinal cell death in the SLOS rat model, which is exacerbated by intense light. Furthermore, the results predict light-dependent potentiation of retinal degeneration in SLOS patients, and the possible ameliorative effects of antioxidant therapy.
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Affiliation(s)
- Dana K. Vaughan
- Department of Biology, University of Wisconsin Oshkosh, Oshkosh, WI, USA
| | - Neal S. Peachey
- Cleveland VA Medical Center, and Cole Eye Institute, Cleveland Clinic Foundation, Cleveland, OH, USA
| | - Michael J. Richards
- Departments of Ophthalmology and Pharmacological & Physiological Science, Saint Louis University School of Medicine, St Louis, MO, USA
| | - Blake Buchan
- Department of Biology, University of Wisconsin Oshkosh, Oshkosh, WI, USA
| | - Steven J. Fliesler
- Departments of Ophthalmology and Pharmacological & Physiological Science, Saint Louis University School of Medicine, St Louis, MO, USA
- Corresponding author. Dr Steven J. Fliesler, Saint Louis University Eye Institute, 1755 S. Grand Blvd, St Louis, MO 63104-1540. (S.J. Fliesler)
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26
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Yu H, Wessels A, Tint GS, Patel SB. Partial rescue of neonatal lethality of Dhcr7 null mice by a nestin promoter-driven DHCR7 transgene expression. BRAIN RESEARCH. DEVELOPMENTAL BRAIN RESEARCH 2005; 156:46-60. [PMID: 15862627 DOI: 10.1016/j.devbrainres.2005.01.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/14/2004] [Revised: 01/27/2005] [Accepted: 01/30/2005] [Indexed: 11/20/2022]
Abstract
In humans, genetic disorders affecting post-squalene cholesterol biosynthesis result in a variety of dysmorphology syndromes. One key feature of all of these is the presence of mental retardation and another is the lack of a robust genotype-phenotype correlation. Knockout mice defective in the 3beta hydroxysterol Delta7 reductase (Dhcr7), a model for the most common of such disorders in humans, the Smith-Lemli-Opitz syndrome, all die within 24 h of birth. The cause of this postnatal mortality in these mice has not been fully established. In the present study, we tested the hypothesis that CNS dysfunction was a major cause of this lethality and investigated whether transgenic expression of normal human DHCR7 in neuronal tissues could rescue this neonatal lethality. Transgenic mice, expressing DHCR7 driven by murine nestin promoter, were bred onto Dhcr7 knock-out (Dhcr7(-1-)) background and resulted in a partial rescue of neonatal lethality in 11 of 91 (12%) of transgene-positive Dhcr7(-1-) pups. Despite biochemical analyses that showed continued profound cholesterol deficiency in brain, rescued animals survived between 3 and 17 days. Thus, one important conclusion to be drawn is that defects in CNS in Dhcr7 knockout mice may contribute to the early lethality. Another conclusion is that even small and subtle changes in the brain sterol metabolism were sufficient to enable rescue. These data also provide important clues as to the cause of the variable expressivity seen in SLOS.
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Affiliation(s)
- Hongwei Yu
- Division of Endocrinology, Diabetes and Medical Genetics, Medical University of South Carolina, STR 541, 114 Doughty Street, Charleston, SC 29403, USA.
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27
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Merkens LS, Connor WE, Linck LM, Lin DS, Flavell DP, Steiner RD. Effects of dietary cholesterol on plasma lipoproteins in Smith-Lemli-Opitz syndrome. Pediatr Res 2004; 56:726-32. [PMID: 15319461 DOI: 10.1203/01.pdr.0000141522.14177.4f] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Smith-Lemli-Opitz syndrome is a condition of impaired cholesterol synthesis that is caused by mutations in DHCR7 encoding 7-dehydrocholesterol-Delta7 reductase. Birth defects and mental retardation are characteristic. Deficient plasma and tissue cholesterol and excess cholesterol precursors 7 and 8 dehydrocholesterol (7DHC and 8DHC) contribute to the pathogenesis. Cholesterol is transported to tissues via lipoproteins. We measured the effect of dietary cholesterol (egg yolk) on plasma lipoproteins to evaluate this potential treatment. We used the enzymatic method to measure total sterols in lipoproteins (n=12) and plasma (n=16). In addition, we analyzed individual plasma sterols by a gas chromatographic method. Samples were evaluated after 3 wk of a cholesterol-free diet and after 6-19 mo of dietary cholesterol. We also analyzed the distribution of sterols in lipoproteins and the apolipoprotein E genotype. Dietary cholesterol significantly increased the total sterols in plasma (2.22 +/- 0.13 to 3.10 +/- 0.22; mean +/- SEM; p < 0.002), in LDL (0.98 +/- 0.13 to 1.52 +/- 0.17 mM), and in HDL (0.72 +/- 0.04 to 0.92 +/- 0.07). Plasma cholesterol increased (1.78 +/- 0.16 to 2.67 +/- 0.25 mM; p < 0.007) and plasma 7DHC decreased in 10 children, but the mean decrease was not significant. The distribution of individual sterols in each lipoprotein fraction was similar to the distribution in plasma. The baseline cholesterol and the response to dietary cholesterol was the same in children with 3/3 and 3/4 apolipoprotein E genotypes. Dietary cholesterol increased total sterols in plasma, LDL, and HDL in children with Smith-Lemli-Opitz syndrome. These favorable increases in the lipoproteins are potentially therapeutic for this condition.
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Affiliation(s)
- Louise S Merkens
- Department of Pediatrics, Child Development and Rehabilitation Center, Doernbecher Children's Hospital, OR Health & Science University, CDRC-F, 707 SW Gaines, Portland, OR 97239, USA
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28
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Shim YH, Bae SH, Kim JH, Kim KR, Kim CJ, Paik YK. A novel mutation of the human 7-dehydrocholesterol reductase gene reduces enzyme activity in patients with holoprosencephaly. Biochem Biophys Res Commun 2004; 315:219-23. [PMID: 15013448 DOI: 10.1016/j.bbrc.2004.01.041] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2003] [Indexed: 11/30/2022]
Abstract
Defects in cholesterol biosynthesis genes are recognized as a leading cause for holoprosencephaly (HPE). Previous reports suggest that mutations of human 7-dehydrocholesterol reductase (Dhcr7), which catalyzes the final step of cholesterol biosynthesis, may cause HPE [Clin. Genet. 53 (1998) 155]. To determine whether Dhcr7 mutations are involved in HPE pathogenesis, we analyzed the sequence of exon 9, which contains both a catalytic domain and a mutational hot spot. We examined 36 prematurely terminated fetuses with HPE at their gestation ages in the range from 21 to 33 weeks by single strand conformation polymorphism analysis and DNA sequencing. A novel missense mutation was identified: G344D. Dhcr7 enzyme assays using overexpressed recombinant mutant proteins revealed altered enzyme activity. Mutant G344D harbored less than 50% of enzyme activity compared with the control. Two previously reported mutations, R404C and G410S, abolished enzyme activity. These results suggest that mutation of the Dhcr7 gene is involved in HPE pathogenesis.
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Affiliation(s)
- Yhong-Hee Shim
- Department of Biological Sciences and Bio/Molecular Informatics Center, Konkuk University, Seoul 143-701, Republic of Korea.
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29
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Jira PE, Waterham HR, Wanders RJA, Smeitink JAM, Sengers RCA, Wevers RA. Smith-Lemli-Opitz syndrome and the DHCR7 gene. Ann Hum Genet 2003; 67:269-80. [PMID: 12914579 DOI: 10.1046/j.1469-1809.2003.00034.x] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
Smith-Lemli-Opitz syndrome, a severe developmental disorder associated with multiple congenital anomalies, is caused by a defect of cholesterol biosynthesis. Low cholesterol and high concentrations of its direct precursor, 7-dehydrocholesterol, in plasma and tissues are the diagnostic biochemical hallmarks of the syndrome. The plasma sterol concentrations correlate with severity and disease outcome. Mutations in the DHCR7 gene lead to deficient activity of 7-dehydrocholesterol reductase (DHCR7), the final enzyme of the cholesterol biosynthetic pathway. The human DHCR7 gene is localised on chromosome 11q13 and its structure has been characterized. Ninety-one different mutations in the DHCR7 gene have been published to date. This paper is a review of the clinical, biochemical and molecular genetic aspects.
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Affiliation(s)
- P E Jira
- Department of Pediatrics, University Medical Centre Nijmegen, 6500 HB Nijmegen, the Netherlands
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30
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Xiong Q, Ruan B, Whitby FG, Tuohy RP, Belanger TL, Kelley RI, Wilson WK, Schroepfer GJ. A colorimetric assay for 7-dehydrocholesterol with potential application to screening for Smith-Lemli-Opitz syndrome. Chem Phys Lipids 2002; 115:1-15. [PMID: 12047895 DOI: 10.1016/s0009-3084(01)00205-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Smith-Lemli-Opitz syndrome (SLOS; MIM 270400) is a genetic disorder characterized by hypocholesterolemia and elevated 7-dehydrocholesterol (7DHC) levels resulting from mutations affecting 7-dehydrocholesterol reductase. We describe a colorimetric assay for 7DHC with potential application to large-scale screening for SLOS. Reaction of 7DHC and its esters with the Liebermann-Burchard reagent resulted in a brief initial absorbance at 510 nm (pink color) followed by an absorbance at 620 nm (blue color) after 2 min, while cholesterol samples were essentially colorless. The assay could identify typical SLOS blood samples by their pink color and increased absorbance at 620 nm after 2 min. Colorimetric identification of mild SLOS cases requires monitoring of the transient absorbance at 510 nm, which must be detected immediately after rapid, consistent mixing of the reagents. The need for special mixing devices and rigorous validation precludes sporadic use of the assay for diagnosing suspected SLOS cases. We also studied the stability of 7DHC in dried SLOS blood spots on Guthrie cards, which are widely used for archiving neonatal blood. Decomposition of 7DHC was effectively retarded by storage at low temperature and by precoating of the cards with antioxidants. The combined results provide a foundation for development of a simple, automated test for SLOS screening.
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Affiliation(s)
- Quanbo Xiong
- Department of Biochemistry and Cell Biology, Rice University, MS140, 6100 Main Street, Houston, TX 77005-1892, USA
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31
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Wassif CA, Vied D, Tsokos M, Connor WE, Steiner RD, Porter FD. Cholesterol storage defect in RSH/Smith-Lemli-Opitz syndrome fibroblasts. Mol Genet Metab 2002; 75:325-34. [PMID: 12051964 DOI: 10.1016/s1096-7192(02)00010-0] [Citation(s) in RCA: 43] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The RSH/Smith-Lemli-Opitz syndrome (SLOS) is a multiple malformation/mental retardation syndrome caused by an inborn error of cholesterol synthesis. Mutations in the 3beta-hydroxysteroid Delta(7)-reductase gene result in impaired enzymatic reduction of 7-dehydrocholesterol (7-DHC) to cholesterol. Cells obtain cholesterol by either de novo synthesis or from exogenous sources by the binding and uptake of low density lipoprotein (LDL) particles. Because de novo synthesis of cholesterol is impaired in SLOS, current investigational therapy for SLOS consists of dietary cholesterol supplementation. However, the potential effects of elevated intracellular levels of 7-DHC on intracellular LDL metabolism have not been described. We now report that in addition to the primary defect in de novo cholesterol synthesis, SLOS fibroblasts have a secondary defect of LDL cholesterol metabolism. Staining of fibroblasts with filipin, a fluorescent polyene antibiotic which binds unesterified sterols, shows that SLOS fibroblasts accumulate unesterified sterols. Further studies show that this increased filipin staining was due to an abnormal accumulation of LDL derived cholesterol rather than due to storage of endogenously synthesized 7-dehydrocholesterol (7-DHC). We have also found that SLOS fibroblasts failed to degrade LDL at a normal rate, and examination of SLOS fibroblasts by electron microscopy demonstrated the formation of lysosomal inclusions similar to that seen in Niemann-Pick type C (NPC) cells. We propose that 7-DHC may directly or indirectly inhibit the function of the NPC protein through its sterol-sensing domain (SSD), and that 7-DHC may perturb the function of other SSD containing proteins in SLOS.
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Affiliation(s)
- Christopher A Wassif
- Unit on Molecular Dysmorphology, Heritable Disorders Branch, National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD 20892, USA
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Abstract
An increasing number of genetically engineered animals are produced worldwide for use in both basic and applied research. Here, I provide an update of some of the latest mouse knockouts in The Jackson Laboratory Transgenic/Targeted Mutation Database (TBASE), concentrating on those associated with male infertility and neuropathology.
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Guo LW, Shackleton CH, Wilson WK. Synthesis of ring B unsaturated estriols. Confirming the structure of a diagnostic analyte for Smith-Lemli-Opitz syndrome. Org Lett 2001; 3:2547-50. [PMID: 11483057 DOI: 10.1021/ol016224j] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
[structure: see text] Brief partial syntheses are described for ring B unsaturated estriols, which are candidate metabolites diagnostic for Smith-Lemli-Opitz syndrome prenatally. These steroids are also likely metabolites of the Premarin preparation used in estrogen replacement therapy. Equilin (8) was converted in three steps to 7-dehydroestriol, which was isomerized to 8-dehydroestriol. The simplicity of the transformations belies the lability of these previously inaccessible metabolites and their synthetic precursors.
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Affiliation(s)
- L W Guo
- Department of Biochemistry and Cell Biology, Rice University, Houston, Texas 77005, USA
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Jeng LB, Tarvin R, Robin NH. Genetic advances in central nervous system malformations in the fetus and neonate. Semin Pediatr Neurol 2001; 8:89-99. [PMID: 11464961 DOI: 10.1053/spen.2001.24836] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Malformations of the central nervous system (CNS) are commonly encountered by the pediatric neurologist when called to evaluate a fetus or newborn. Such malformations may be isolated or appear as part of a genetic syndrome. In the past few years there have been great advances in identifying the genes and genetic alterations for many isolated CNS malformations and syndromes with CNS malformations. Therefore, it is important to look for associated anomalies in any infant with a CNS malformation, as well as consideration of the rest of the family. We have chosen four malformations (holoprosencephaly, hydrocephalus, lissencephaly, and schizencephaly) to serve as a paradigm for genetic malformations of the CNS. Understanding the underlying genetic etiology of a disorder allows us to give more accurate recurrence risk counseling, to better estimate potential complications, and to better manage the patient's care. As research continues, additional malformations and syndromes will be understood on the genetic level, and combining this genetic information with neurologic understanding will translate into better medical care for the patient.
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Affiliation(s)
- L B Jeng
- Department of Genetics, Case Western Reserve University School of Medicine, University Hospitals of Cleveland, OH, USA
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