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Hirtzel E, Edwards M, Freitas D, Liu Z, Wang F, Yan X. Aziridination-Assisted Mass Spectrometry of Nonpolar Sterol Lipids with Isomeric Resolution. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 2023; 34:1998-2005. [PMID: 37523498 PMCID: PMC10863044 DOI: 10.1021/jasms.3c00161] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/30/2023] [Revised: 07/13/2023] [Accepted: 07/17/2023] [Indexed: 08/02/2023]
Abstract
Characterization of nonpolar lipids is crucial due to their essential biological functions and ability to exist in various isomeric forms. In this study, we introduce the N-H aziridination method to target carbon-carbon double bonds (C═C bonds) in nonpolar sterol lipids. The resulting fragments are readily dissociated upon collision-induced dissociation, generating specific fragment ions for C═C bond position determination and fingerprint fragments for backbone characterization. This method significantly enhances lipid ionization efficiency, thereby improving the sensitivity and accuracy of nonpolar lipid analysis. We demonstrated that aziridination of sterols leads to distinctive fragmentation pathways for chain and ring C═C bonds, enabling the identification of sterol isomers such as desmosterol and 7-dehydrocholesterol. Furthermore, aziridination can assist in identifying the sterol backbone by providing fingerprint tandem mass spectra. We also demonstrated the quantitative capacity of this approach with a limit of detection of 10 nM in the solvent mixture of methanol and water. To test the feasibility of this method in complex biological samples, we used mouse prostate cancerous tissues and found significant differences in nonpolar lipid profiles between healthy and cancerous samples. The high efficiency and specificity of aziridination-assisted mass spectrometric analysis, as well as its quantitative analysis ability, make it highly suitable for broad applications in nonpolar lipid research.
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Affiliation(s)
- Erin Hirtzel
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Madison Edwards
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Dallas Freitas
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843, United States
| | - Ziying Liu
- Center
for Translational Cancer Research, Texas
A&M University, Houston, Texas 77030, United States
| | - Fen Wang
- Center
for Translational Cancer Research, Texas
A&M University, Houston, Texas 77030, United States
| | - Xin Yan
- Department
of Chemistry, Texas A&M University, College Station, Texas 77843, United States
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2
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Hill C, Noureldein M, Karkhanis P, Kinning E, Vijay S, Gowda H. First case of desmosterolosis diagnosed by prenatal whole exome sequencing. Am J Med Genet A 2023; 191:859-863. [PMID: 36538928 DOI: 10.1002/ajmg.a.63083] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2022] [Revised: 11/15/2022] [Accepted: 12/01/2022] [Indexed: 12/24/2022]
Abstract
Desmosterolosis is a rare autosomal recessive disorder of cholesterol biosynthesis resulting in multiple congenital abnormalities and syndromic intellectual disability. It is caused by defects in DHCR24, the gene encoding 3-β-hydroxysterol-24-reductase (24-dehydrocholesterol reductase), which acts in conversion of cholesterol precursor desmosterol, hence resulting in elevated plasma desmosterol levels. To date, desmosterolosis has been reported in 10 patients. Here we report an eleventh patient with desmosterolosis, and the first one to be diagnosed antenatally. Diagnosis was made on whole exome sequencing after amniocentesis due to complex antenatal abnormalities including cerebellar hypoplasia, microgyria, aortic stenosis, and renal tract abnormalities. Sterol quantitation was subsequently done postnatally, which supported the diagnosis. Although the nonspecific features make desmosterolosis difficult to suspect, we demonstrate that disorders of cholesterol synthesis can be considered as a differential diagnosis antenatally.
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Affiliation(s)
- Chloe Hill
- Neonatal Unit, Heartlands Hospital, University Hospitals Birmingham, Birmingham, UK
| | - Mona Noureldein
- Neonatal Unit, Heartlands Hospital, University Hospitals Birmingham, Birmingham, UK
| | - Pallavi Karkhanis
- Fetal Medicine, Heartlands Hospital, University Hospitals Birmingham, Birmingham, UK
| | - Esther Kinning
- Clinical Genetics, Birmingham Women's and Children's, Birmingham, UK
| | - Suresh Vijay
- Paediatric Inherited Metabolic Disease, Birmingham Women's and Children's, Birmingham, UK
| | - Harsha Gowda
- Neonatal Unit, Heartlands Hospital, University Hospitals Birmingham, Birmingham, UK
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3
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Coupe S, Hertzog A, Foran C, Tolun AA, Suthern M, Chung CWT, Ellaway C. Keeping you on your toes: Smith-Lemli-Opitz Syndrome is an easily missed cause of developmental delays. Clin Case Rep 2023; 11:e6920. [PMID: 36814711 PMCID: PMC9939576 DOI: 10.1002/ccr3.6920] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 10/10/2022] [Accepted: 12/28/2022] [Indexed: 02/22/2023] Open
Abstract
Smith-Lemli-Opitz syndrome (SLOS) is a relatively common genetic cause of developmental delay and may only present in conjunction with 2,3 toe syndactyly. This case series illustrates a milder phenotype of SLOS, where the predominant findings are neurocognitive in the presence of 2,3 toe syndactyly.
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Affiliation(s)
- Simone Coupe
- NSW Biochemical Genetics ServiceThe Children's Hospital at WestmeadWestmeadNew South WalesAustralia
| | - Ashley Hertzog
- NSW Biochemical Genetics ServiceThe Children's Hospital at WestmeadWestmeadNew South WalesAustralia,Faculty of Medicine and HealthUniversity of SydneyWestmeadNew South WalesAustralia
| | - Carolyn Foran
- NSW Biochemical Genetics ServiceThe Children's Hospital at WestmeadWestmeadNew South WalesAustralia
| | - Adviye Ayper Tolun
- NSW Biochemical Genetics ServiceThe Children's Hospital at WestmeadWestmeadNew South WalesAustralia,Faculty of Medicine and HealthUniversity of SydneyWestmeadNew South WalesAustralia
| | - Megan Suthern
- Paediatric DepartmentWagga Wagga Base HospitalWagga WaggaNew South WalesAustralia,Rural Clinical School, Faculty of Medicine and HealthUniversity of New South WalesWagga WaggaNew South WalesAustralia
| | - Clara W. T. Chung
- Department of Clinical GeneticsLiverpool HospitalLiverpoolNew South WalesAustralia,School of Women's and Children's HealthUniversity of New South WalesSydneyNew South WalesAustralia
| | - Carolyn Ellaway
- Faculty of Medicine and HealthUniversity of SydneyWestmeadNew South WalesAustralia,Genetic Metabolic Disorders ServiceThe Children's Hospital at WestmeadWestmeadNew South WalesAustralia
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4
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Chen Q, Chen H, Wang M, Qiu L, Xi F, Jiang Y, Lv M, Huang HF, Luo Q. The association between alteration of maternal lipid levels and birthweight at term: A within-family comparison. Front Endocrinol (Lausanne) 2022; 13:989663. [PMID: 36246889 PMCID: PMC9562839 DOI: 10.3389/fendo.2022.989663] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/08/2022] [Accepted: 09/16/2022] [Indexed: 11/29/2022] Open
Abstract
CONTEXT Maternal lipid levels affect birthweight and the long-term health of the offsprings. However, this association could be influenced by genetic and other common factors. OBJECTIVE This work aimed to explore the relationship between maternal lipid levels and birthweight of two pregnancies in the same mother. METHODS In this population-based cohort study, 705 women and their 1 410 offsprings were included. From an initial sample of women with more than one singleton birth in the database, we made the following exclusions: missing data for pre-pregnancy BMI, pregnancy weight gain, birthweight and lipid values; maternal age less than 19 or older than 44 years old; gestational age < 37 weeks or > 41weeks, gestational diabetes mellitus/diabetic. In the second and third trimesters, serum samples were collected for the determination of fasting total cholesterol (TC), triglycerides (TG), high-density lipoprotein cholesterol (HDL-C), and low-density lipoprotein cholesterol (LDL-C) levels. Then we assessed the association between maternal lipids and birthweight. RESULTS Infants of women whose 2nd-trimester TC increased by 10th-20th percentile (-0.92~-0.56 mmol/L) from 1st to 2nd pregnancy were 239.69 (62.32~417.06) g lighter at birth than were infants of women those of 40th-50th percentile (-0.20~-0.03 mmol/L). Parity, gestational age, neonatal gender, maternal pre-pregnancy body mass index, maternal weight gain, and 3rd-trimester TC and HDL-C were all associated with higher birth weight. Every unit increase in TC in the third trimester increases birthweight by 53.13 (14.32 ~91.94) g. CONCLUSION Maternal TC level is associated with birthweight independent of shared genes. TC may be used to guide diet and predict birthweight combined with ultrasound and other indicators.
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Affiliation(s)
- Qinqing Chen
- Department of Obstetrics, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Huiqi Chen
- School of Public Health, Sun Yat-sen University, Guangzhou, China
| | - Minmin Wang
- Department of Obstetrics, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Liping Qiu
- Department of Obstetrics, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Fangfang Xi
- Department of Obstetrics, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Ying Jiang
- Department of Obstetrics, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Min Lv
- Department of Obstetrics, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - He-Feng Huang
- Department of Obstetrics, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- *Correspondence: Qiong Luo, ; He-Feng Huang,
| | - Qiong Luo
- Department of Obstetrics, Women’s Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- *Correspondence: Qiong Luo, ; He-Feng Huang,
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5
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Lasunción MA, Martínez-Botas J, Martín-Sánchez C, Busto R, Gómez-Coronado D. Cell cycle dependence on the mevalonate pathway: Role of cholesterol and non-sterol isoprenoids. Biochem Pharmacol 2021; 196:114623. [PMID: 34052188 DOI: 10.1016/j.bcp.2021.114623] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2021] [Revised: 05/25/2021] [Accepted: 05/25/2021] [Indexed: 12/16/2022]
Abstract
The mevalonate pathway is responsible for the synthesis of isoprenoids, including sterols and other metabolites that are essential for diverse biological functions. Cholesterol, the main sterol in mammals, and non-sterol isoprenoids are in high demand by rapidly dividing cells. As evidence of its importance, many cell signaling pathways converge on the mevalonate pathway and these include those involved in proliferation, tumor-promotion, and tumor-suppression. As well as being a fundamental building block of cell membranes, cholesterol plays a key role in maintaining their lipid organization and biophysical properties, and it is crucial for the function of proteins located in the plasma membrane. Importantly, cholesterol and other mevalonate derivatives are essential for cell cycle progression, and their deficiency blocks different steps in the cycle. Furthermore, the accumulation of non-isoprenoid mevalonate derivatives can cause DNA replication stress. Identification of the mechanisms underlying the effects of cholesterol and other mevalonate derivatives on cell cycle progression may be useful in the search for new inhibitors, or the repurposing of preexisting cholesterol biosynthesis inhibitors to target cancer cell division. In this review, we discuss the dependence of cell division on an active mevalonate pathway and the role of different mevalonate derivatives in cell cycle progression.
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Affiliation(s)
- Miguel A Lasunción
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain.
| | - Javier Martínez-Botas
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain
| | - Covadonga Martín-Sánchez
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain
| | - Rebeca Busto
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain
| | - Diego Gómez-Coronado
- Servicio de Bioquímica-Investigación, Hospital Universitario Ramón y Cajal, IRyCIS, Madrid, Spain; CIBER de Fisiopatología de la Obesidad y Nutrición (CIBEROBN), Instituto de Salud Carlos III (ISCIII), Spain.
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6
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Fliesler SJ. EDITOR'S PERSPECTIVE: On the verge of translation: Combined cholesterol-antioxidant supplementation as a potential therapeutic intervention for Smith-Lemli-Opitz syndrome. Exp Eye Res 2020; 202:108390. [PMID: 33307076 DOI: 10.1016/j.exer.2020.108390] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Affiliation(s)
- Steven J Fliesler
- Departments of Ophthalmology and Biochemistry and the Neuroscience Graduate Program, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo- the State University of New York, Buffalo, NY, 14215-1129, USA; Research Service, Western New York Healthcare System, Buffalo, NY, 14215-1129, USA.
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7
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Role of cholesterol metabolism in the anticancer pharmacology of selective estrogen receptor modulators. Semin Cancer Biol 2020; 73:101-115. [PMID: 32931953 DOI: 10.1016/j.semcancer.2020.08.015] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 08/13/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022]
Abstract
Selective estrogen receptor modulators (SERMs) are a class of compounds that bind to estrogen receptors (ERs) and possess estrogen agonist or antagonist actions in different tissues. As such, they are widely used drugs. For instance, tamoxifen, the most prescribed SERM, is used to treat ERα-positive breast cancer. Aside from their therapeutic targets, SERMs have the capacity to broadly affect cellular cholesterol metabolism and handling, mainly through ER-independent mechanisms. Cholesterol metabolism reprogramming is crucial to meet the needs of cancer cells, and different key processes involved in cholesterol homeostasis have been associated with cancer progression. Therefore, the effects of SERMs on cholesterol homeostasis may be relevant to carcinogenesis, either by contributing to the anticancer efficacy of these compounds or, conversely, by promoting resistance to treatment. Understanding these aspects of SERMs actions could help to design more efficacious therapies. Herein we review the effects of SERMs on cellular cholesterol metabolism and handling and discuss their potential in anticancer pharmacology.
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8
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Wilkins-Haug L. Genetic innovations and our understanding of stillbirth. Hum Genet 2020; 139:1161-1172. [PMID: 32318853 DOI: 10.1007/s00439-020-02146-2] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Accepted: 02/27/2020] [Indexed: 12/11/2022]
Abstract
Stillbirth after 20 weeks gestation happens in 1 in 200 pregnancies and occurs more commonly than neonatal loss and sudden infant death syndrome (SIDs) combined. The stillbirth rate is several times greater in low as opposed to high-resource countries. However, among high-resource countries, although a lower overall stillbirth rate exists, there has been little change for several decades. Molecular genetic technologies are emerging as important contributors to our understanding of stillbirth. Initially, genetic etiologies included alterations in chromosome number or structure such as aneuploidy and microduplications and deletions. More recently, next-generation sequencing analysis in two genetic conditions, Smith Lemli Optiz Syndrome (SLOs) and the channelopathy disorders (such as long QT syndrome (LQTS)) provide examples into the association of pathogenic gene variants with stillbirth. Although these specific conditions individually account for only a small number of stillbirths, investigating these disorders provides a new and innovative approach for further understanding genetic contributors to adverse pregnancy outcomes. Our knowledge of the role of genetic disease as an etiology for stillbirth is elementary. Genomic interrogation of maternal-fetal genotypes, gene-gene, and genotype-environment interaction is lacking in stillbirth research. At the DNA sequence level, further investigation of variants of unknown significance is an opportunity for exploration of biologic pathways of importance to pregnancy loss. This review concentrates on SLO as an example of a single gene disorder with a high carrier but low affected liveborn proband rate. The channelopathy disorders are included as initial examples of genetic conditions with variable presentation including an association with sudden infant death syndrome. Highlighted are the challenges when numerous genes and variants are involved, and the task of assigning pathogenicity. The advantages and limitations of genetic evaluations are presented and avenues for further research considered.
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Affiliation(s)
- Louise Wilkins-Haug
- Division of Maternal Fetal Medicine, Department of Obstetrics, Gynecology and Reproductive Biology, Brigham and Women's Hospital, Harvard Medical School, 75 Francis Street, Boston, MA, 01770, USA.
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9
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Schoner K, Witsch-Baumgartner M, Behunova J, Petrovic R, Bald R, Kircher SG, Ramaswamy A, Kluge B, Meyer-Wittkopf M, Schmitz R, Fritz B, Zschocke J, Laccone F, Rehder H. Smith-Lemli-Opitz syndrome - Fetal phenotypes with special reference to the syndrome-specific internal malformation pattern. Birth Defects Res 2019; 112:175-185. [PMID: 31840946 PMCID: PMC7432161 DOI: 10.1002/bdr2.1620] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2019] [Revised: 11/04/2019] [Accepted: 11/05/2019] [Indexed: 01/31/2023]
Abstract
Background Autosomal‐recessive SLOS is caused by mutations in the DHCR7 gene. It is defined as a highly variable complex of microcephaly with intellectual disability, characteristic facies, hypospadias, and polysyndactyly. Syndrome diagnosis is often missed at prenatal ultrasound and fetal autopsy Methods We performed autopsies and DHCR7 gene analyses in eight fetuses suspected of having SLOS and measured cholesterol values in long‐term formalin‐fixed tissues of an additional museum exhibit Results Five of the nine fetuses presented classical features of SLOS, including four cases with atrial/atrioventricular septal defects and renal anomalies, and one with additional bilateral renal agenesis and a Dandy‐Walker cyst. These cases allowed for diagnosis at autopsy and subsequent SLOS diagnosis in two siblings. Two fetuses were mildly affected and two fetuses showed additional holoprosencephaly. These four cases and the exhibit had escaped diagnosis at autopsy. The case with bilateral renal agenesis presented a novel combination of a null allele and a putative C‐terminus missense mutation in the DHCR7 gene Conclusions In view of the discrepancy between the prevalence of SLOS among newborns and the carrier frequency of a heterozygous DHCR7 gene mutation, the syndrome‐specific internal malformation pattern may be helpful not to miss SLOS diagnosis in fetuses at prenatal ultrasound and fetal autopsy
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Affiliation(s)
- Katharina Schoner
- Institute of Pathology, Philipps-University Marburg, Marburg, Germany
| | | | - Jana Behunova
- Institute of Medical Genetics, Medical University Vienna, Vienna, Austria
| | - Robert Petrovic
- Institute of Medical Biology, Comenius University Bratislava, Bratislava, Slovakia
| | - Rainer Bald
- Clinic of Gynecology and Obstetrics, Klinikum Leverkusen, Leverkusen, Germany
| | - Susanne G Kircher
- Institute of Medical Genetics, Medical University Vienna, Vienna, Austria
| | - Annette Ramaswamy
- Institute of Pathology, Philipps-University Marburg, Marburg, Germany
| | - Britta Kluge
- Institute of Medical Genetics, Medical University Vienna, Vienna, Austria
| | | | - Ralf Schmitz
- Clinic of Gynecology and Obstetrics, University Clinic Muenster, Münster, Germany
| | - Barbara Fritz
- Institute of Human Genetics, Philipps-University Marburg, Marburg, Germany
| | - Johannes Zschocke
- Institute of Human Genetics, Medical University Innsbruck, Innsbruck, Austria
| | - Franco Laccone
- Institute of Medical Genetics, Medical University Vienna, Vienna, Austria
| | - Helga Rehder
- Institute of Pathology, Philipps-University Marburg, Marburg, Germany.,Institute of Medical Genetics, Medical University Vienna, Vienna, Austria
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10
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Konecna A, Toth Hervay N, Bencova A, Morvova M, Sikurova L, Jancikova I, Gaskova D, Gbelska Y. Erg6 gene is essential for stress adaptation in Kluyveromyces lactis. FEMS Microbiol Lett 2018; 365:5162844. [PMID: 30398655 DOI: 10.1093/femsle/fny265] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2018] [Accepted: 11/05/2018] [Indexed: 01/20/2023] Open
Abstract
We investigated the effect of Kluyveromyces lactis ERG6 gene deletion on plasma membrane function and showed increased susceptibility of mutant cells to salt stress, cationic drugs and weak organic acids. Contrary to Saccharomyces cerevisiae, Klerg6 mutant cells exhibited increased tolerance to tunicamycin. The content of cell wall polysacharides did not significantly vary between wild-type and mutant cells. Although the expression of the NAD+-dependent glycerol 3-phosphate dehydrogenase (KlGPD1) in the Klerg6 mutant cells was only half of that in the parental strain, it was induced in the presence of calcofluor white. Also, cells exposed to this drug accumulated glycerol. The absence of KlErg6p led to plasma membrane hyperpolarization but had no statistically significant influence on the plasma membrane fluidity. We propose that the phenotype of Klerg6 mutant cells to a large extent was a result of the reduced activity of specific plasma membrane proteins that require proper lipid composition for full activity.
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Affiliation(s)
- Alexandra Konecna
- Faculty of Sciences, Department of Microbiology and Virology, Comenius University in Bratislava, Ilkovicova 6, 842 15 Bratislava, Slovakia
| | - Nora Toth Hervay
- Faculty of Sciences, Department of Microbiology and Virology, Comenius University in Bratislava, Ilkovicova 6, 842 15 Bratislava, Slovakia
| | - Alexandra Bencova
- Faculty of Sciences, Department of Microbiology and Virology, Comenius University in Bratislava, Ilkovicova 6, 842 15 Bratislava, Slovakia
| | - Marcela Morvova
- Faculty of Mathematics, Physics and Informatics F1, Comenius University in Bratislava, Mlynska dolina 6280, 842 48 Bratislava, Slovakia
| | - Libusa Sikurova
- Faculty of Mathematics, Physics and Informatics F1, Comenius University in Bratislava, Mlynska dolina 6280, 842 48 Bratislava, Slovakia
| | - Iva Jancikova
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 2027/3, 121 16 Prague, Czech Republic
| | - Dana Gaskova
- Faculty of Mathematics and Physics, Charles University, Ke Karlovu 2027/3, 121 16 Prague, Czech Republic
| | - Yvetta Gbelska
- Faculty of Sciences, Department of Microbiology and Virology, Comenius University in Bratislava, Ilkovicova 6, 842 15 Bratislava, Slovakia
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11
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Fliesler SJ, Xu L. Oxysterols and Retinal Degeneration in a Rat Model of Smith-Lemli-Opitz Syndrome: Implications for an Improved Therapeutic Intervention. Molecules 2018; 23:E2720. [PMID: 30360379 PMCID: PMC6222618 DOI: 10.3390/molecules23102720] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2018] [Revised: 10/18/2018] [Accepted: 10/19/2018] [Indexed: 01/31/2023] Open
Abstract
Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive human disease caused by mutations in the gene encoding 7-dehydrocholesterol (7DHC) reductase (DHCR7), resulting in abnormal accumulation of 7DHC and reduced levels of cholesterol in bodily tissues and fluids. A rat model of the disease has been created by treating normal rats with the DHCR7 inhibitor, AY9944, which causes progressive, irreversible retinal degeneration. Herein, we review the features of this disease model and the evidence linking 7DHC-derived oxysterols to the pathobiology of the disease, with particular emphasis on the associated retinal degeneration. A recent study has shown that treating the rat model with cholesterol plus suitable antioxidants completely prevents the retinal degeneration. These findings are discussed with regard to their translational implications for developing an improved therapeutic intervention for SLOS over the current standard of care.
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Affiliation(s)
- Steven J Fliesler
- Departments of Ophthalmology and Biochemistry and Neuroscience Program, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, The State University of New York, Buffalo, NY 14260, USA.
- Research Service, VA Western NY Healthcare System, Buffalo, NY 14260, USA.
| | - Libin Xu
- Department of Medicinal Chemistry, School of Pharmacy, University of Washington, Seattle, WA 98195, USA.
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12
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Herron J, Hines KM, Xu L. Assessment of Altered Cholesterol Homeostasis by Xenobiotics Using Ultra-High Performance Liquid Chromatography-Tandem Mass Spectrometry. ACTA ACUST UNITED AC 2018; 78:e65. [PMID: 30320450 DOI: 10.1002/cptx.65] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023]
Abstract
Cholesterol and cholesterol-derived oxysterols are critical for embryonic development, synapse formation and function, and myelination, among other biological functions. Indeed, alterations in levels of cholesterol, sterol precursors, and oxysterols result in a variety of developmental disorders, emphasizing the importance of cholesterol homeostasis. The ability of xenobiotics to reproduce similar phenotypes by altering cholesterol homeostasis has increasingly become of interest. Therefore, the ability to quantitatively assess alterations in cholesterol homeostasis resulting from exposure to xenobiotics is of value. This unit describes methods for the quantitative assessment of altered post-squalene cholesterol biosynthesis and subsequent oxysterol formation in various sample types using ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Understanding alterations in cholesterol homeostasis resulting from xenobiotic exposure can provide key insight into the toxicant's mechanism of action and resulting phenotype. © 2018 by John Wiley & Sons, Inc.
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Affiliation(s)
- Josi Herron
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington
| | - Kelly M Hines
- Department of Medicinal Chemistry, University of Washington, Seattle, Washington
| | - Libin Xu
- Department of Environmental and Occupational Health Sciences, University of Washington, Seattle, Washington.,Department of Medicinal Chemistry, University of Washington, Seattle, Washington
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13
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Hong M, Krauss RS. Modeling the complex etiology of holoprosencephaly in mice. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2018; 178:140-150. [PMID: 29749693 DOI: 10.1002/ajmg.c.31611] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/16/2018] [Revised: 03/28/2018] [Accepted: 04/02/2018] [Indexed: 12/14/2022]
Abstract
Holoprosencephaly (HPE) is a common developmental defect caused by failure to define the midline of the forebrain and/or midface. HPE is associated with heterozygous mutations in Nodal and Sonic hedgehog (SHH) pathway components, but clinical presentation is highly variable, and many mutation carriers are unaffected. It is therefore thought that such mutations interact with more common modifiers, genetic and/or environmental, to produce severe patterning defects. Modifiers are difficult to identify, as their effects are context-dependent and occur within the complex genetic and environmental landscapes that characterize human populations. This has made a full understanding of HPE etiology challenging. We discuss here the use of mice, a genetically tractable model sensitive to teratogens, as a system to address this challenge. Mice carrying mutations in human HPE genes often display wide variations in phenotypic penetrance and expressivity when placed on different genetic backgrounds, demonstrating the existence of silent HPE modifier genes. Studies with mouse lines carrying SHH pathway mutations on appropriate genetic backgrounds have led to identification of both genetic and environmental modifiers that synergize with the mutations to produce a spectrum of HPE phenotypes. These models favor a scenario in which multiple modifying influences-both genetic and environmental, sensitizing and protective-interact with bona fide HPE mutations to grade phenotypic outcomes. Despite the complex interplay of HPE risk factors, mouse models have helped establish some clear concepts in HPE etiology. A combination of mouse and human cohort studies should improve our understanding of this fascinating and medically important issue.
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Affiliation(s)
- Mingi Hong
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Robert S Krauss
- Department of Cell, Developmental, and Regenerative Biology, Icahn School of Medicine at Mount Sinai, New York, New York
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14
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Peng Y, Myers R, Zhang W, Alexov E. Computational Investigation of the Missense Mutations in DHCR7 Gene Associated with Smith-Lemli-Opitz Syndrome. Int J Mol Sci 2018; 19:E141. [PMID: 29300326 PMCID: PMC5796090 DOI: 10.3390/ijms19010141] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/16/2017] [Revised: 12/29/2017] [Accepted: 12/30/2017] [Indexed: 12/25/2022] Open
Abstract
Smith-Lemli-Opitz syndrome (SLOS) is a cholesterol synthesis disorder characterized by physical, mental, and behavioral symptoms. It is caused by mutations in 7-dehydroxycholesterolreductase gene (DHCR7) encoding DHCR7 protein, which is the rate-limiting enzyme in the cholesterol synthesis pathway. Here we demonstrate that pathogenic mutations in DHCR7 protein are located either within the transmembrane region or are near the ligand-binding site, and are highly conserved among species. In contrast, non-pathogenic mutations observed in the general population are located outside the transmembrane region and have different effects on the conformational dynamics of DHCR7. All together, these observations suggest that the non-classified mutation R228Q is pathogenic. Our analyses indicate that pathogenic effects may affect protein stability and dynamics and alter the binding affinity and flexibility of the binding site.
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Affiliation(s)
- Yunhui Peng
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29630, USA.
| | - Rebecca Myers
- Department of Healthcare Genetics, Clemson University, Clemson, SC 29630, USA.
| | - Wenxing Zhang
- Department of Chemistry, Clemson University, Clemson, SC 29630, USA.
| | - Emil Alexov
- Department of Physics and Astronomy, Clemson University, Clemson, SC 29630, USA.
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15
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Yamauchi Y, Rogers MA. Sterol Metabolism and Transport in Atherosclerosis and Cancer. Front Endocrinol (Lausanne) 2018; 9:509. [PMID: 30283400 PMCID: PMC6157400 DOI: 10.3389/fendo.2018.00509] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2018] [Accepted: 08/14/2018] [Indexed: 01/22/2023] Open
Abstract
Cholesterol is a vital lipid molecule for mammalian cells, regulating fluidity of biological membranes, and serving as an essential constituent of lipid rafts. Mammalian cells acquire cholesterol from extracellular lipoproteins and from de novo synthesis. Cholesterol biosynthesis generates various precursor sterols. Cholesterol undergoes metabolic conversion into oxygenated sterols (oxysterols), bile acids, and steroid hormones. Cholesterol intermediates and metabolites have diverse and important cellular functions. A network of molecular machineries including transcription factors, protein modifiers, sterol transporters/carriers, and sterol sensors regulate sterol homeostasis in mammalian cells and tissues. Dysfunction in metabolism and transport of cholesterol, sterol intermediates, and oxysterols occurs in various pathophysiological settings such as atherosclerosis, cancers, and neurodegenerative diseases. Here we review the cholesterol, intermediate sterol, and oxysterol regulatory mechanisms and intracellular transport machineries, and discuss the roles of sterols and sterol metabolism in human diseases.
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Affiliation(s)
- Yoshio Yamauchi
- Nutri-Life Science Laboratory, Department of Applied Biological Chemistry, Graduate School of Agricultural and Life Sciences, University of Tokyo, Tokyo, Japan
- AMED-CREST, Japan Agency for Medical Research and Development, Tokyo, Japan
- *Correspondence: Yoshio Yamauchi
| | - Maximillian A. Rogers
- Division of Cardiovascular Medicine, Center for Interdisciplinary Cardiovascular Sciences, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, United States
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16
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Rohanizadegan M, Sacharow S. Desmosterolosis presenting with multiple congenital anomalies. Eur J Med Genet 2017; 61:152-156. [PMID: 29175559 DOI: 10.1016/j.ejmg.2017.11.009] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2017] [Revised: 10/26/2017] [Accepted: 11/21/2017] [Indexed: 12/30/2022]
Abstract
Desmosterolosis is a rare multiple congenital anomaly syndrome caused by a defect in the enzyme 3-beta-hydroxysterol delta-24-reductase (DHCR24) in the cholesterol biosynthesis pathway. Defects in this enzyme cause increased level of the cholesterol precursor desmosterol while disrupting development of cholesterol, impacting embryogenesis. A total of 9 cases of desmosterolosis have been reported to date. We report a 20-month-old male from consanguineous parents with multiple congenital anomalies including corpus callosum hypoplasia, facial dysmorphism, cleft palate, pectus deformity, short and wide neck and distal contractures. On analysis of the regions of homozygosity found by microarray, we identified DHCR24 as a candidate gene. Sterol quantitation showed a desmosterol level of 162 μg/mL (nl: 0.82 ± 0.48). Genetic testing confirmed the diagnosis with a homozygous likely pathogenic mutation (p.Glu191Lys) in the DHCR24 gene. Our case expands the known diagnostic spectrum for Desmosterolosis. We suggest considering Desmosterolosis in the differential diagnosis of patients who present with concurrent agenesis of the corpus callosum with white matter atrophy and ventriculomegaly, retromicrognathia with or without cleft palate, hand contractures, and delay of growth and development. Children of consanguineous mattings may be at higher risk for rare recessive disorders and testing for cholesterol synthesis defect should be a consideration for affected children. Initial evaluation can be performed using sterol quantitation, followed by genetic testing.
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Affiliation(s)
- Mersedeh Rohanizadegan
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA
| | - Stephanie Sacharow
- Division of Genetics and Genomics, Boston Children's Hospital, Boston, MA, USA; Harvard Medical School, Boston, MA, USA.
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17
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Sandlers Y. The future perspective: metabolomics in laboratory medicine for inborn errors of metabolism. Transl Res 2017; 189:65-75. [PMID: 28675806 DOI: 10.1016/j.trsl.2017.06.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 06/06/2017] [Accepted: 06/08/2017] [Indexed: 12/22/2022]
Abstract
Metabolomics can be described as a simultaneous and comprehensive analysis of small molecules in a biological sample. Recent technological and bioinformatics advances have facilitated large-scale metabolomic studies in many areas, including inborn errors of metabolism (IEMs). Despite significant improvements in the diagnosis and treatment of some IEMs, it is still challenging to understand how genetic variation affects disease progression and susceptibility. In addition, a search for new more personalized therapies and a growing demand for tools to monitor the long-term metabolic effects of existing therapies set the stage for metabolomics integration in preclinical and clinical studies. While targeted metabolomics approach is a common practice in biochemical genetics laboratories for biochemical diagnosis and monitoring of IEMs, applications of untargeted metabolomics in the clinical laboratories are still in infancy, facing some challenges. It is however, expected in the future to dramatically change the scope and utility of the clinical laboratory playing a significant role in patient management. This review provides an overview of targeted and global, large-scale metabolomic studies applied to investigate various IEMs. We discuss an existing and prospective clinical applications of metabolomics in IEMs for better diagnosis and deep understanding of complex metabolic perturbations associated with the etiology of inherited metabolic disorders.
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Affiliation(s)
- Yana Sandlers
- Department of Chemistry, Cleveland State University, Cleveland, Ohio.
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18
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Wangdee C, Leegwater P, Heuven H, van Steenbeek F, Techakumphu M, Hazewinkel HA. Population genetic analysis and genome-wide association study of patellar luxation in a Thai population of Pomeranian dogs. Res Vet Sci 2017; 111:9-13. [DOI: 10.1016/j.rvsc.2016.11.006] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 11/01/2016] [Accepted: 11/10/2016] [Indexed: 11/24/2022]
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19
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Lazarin GA, Haque IS, Evans EA, Goldberg JD. Smith-Lemli-Opitz syndrome carrier frequency and estimates of in utero mortality rates. Prenat Diagn 2017; 37:350-355. [PMID: 28166604 PMCID: PMC5413855 DOI: 10.1002/pd.5018] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2016] [Revised: 01/23/2017] [Accepted: 01/25/2017] [Indexed: 12/19/2022]
Abstract
Objective To tabulate individual allele frequencies and total carrier frequency for Smith–Lemli–Opitz syndrome (SLOS) and compare expected versus observed birth incidences. Methods A total of 262 399 individuals with no known indication or increased probability of SLOS carrier status, primarily US based, were screened for SLOS mutations as part of an expanded carrier screening panel. Results were retrospectively analyzed to estimate carrier frequencies in multiple ethnic groups. SLOS birth incidences obtained from existing literature were then compared with these data to estimate the effect of SLOS on fetal survival. Results Smith–Lemli–Opitz syndrome carrier frequency is highest in Ashkenazi Jews (1 in 43) and Northern Europeans (1 in 54). Comparing predicted birth incidence with that observed in published literature suggests that approximately 42% to 88% of affected conceptuses experience prenatal demise. Conclusion Smith–Lemli–Opitz syndrome is relatively frequent in certain populations and, because of its impact on prenatal and postnatal morbidity and mortality, merits consideration for routine screening. © 2017 The Authors. Prenatal Diagnosis published by John Wiley & Sons, Ltd. What's already known about this topic?
Smith–Lemli–Opitz syndrome is an autosomal recessive multiple congenital anomaly syndrome with varying frequency estimates. Smith–Lemli–Opitz syndrome is presumed to be associated with an increased risk for pregnancy loss, although this risk has not been quantified.
What does this study add?
By reporting results from a large, diverse tested population, these data define the carrier frequency in multiple ethnic groups. Predicted Smith–Lemli–Opitz syndrome frequency at birth is compared with actual frequencies from previous studies, enabling estimation of the pregnancy loss frequency.
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20
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Prabhu AV, Luu W, Brown AJ. Measuring Activity of Cholesterol Synthesis Enzymes Using Gas Chromatography/Mass Spectrometry. Methods Mol Biol 2017; 1583:211-219. [PMID: 28205177 DOI: 10.1007/978-1-4939-6875-6_16] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/06/2023]
Abstract
The development of gas chromatography/mass spectrometry (GC/MS) technology has improved the ease and efficiency with which sterols in biological samples can be analyzed. Its advantages include that it needs only a small amount of sample, a short analysis time, and has enhanced specificity over traditional methods. Furthermore, a major benefit is its nonselective properties, which means that a complete scan of the sample will display the relative abundance of every sterol in the sample. This property has made it possible to define the abnormal, but distinctive, sterol profiles in a number of inborn errors of cholesterol synthesis. Here, we describe a semiquantitative method to determine relative activity of cholesterol synthesis enzymes. As an example, we measure the relative abundance of the substrate and product sterols of a cholesterol synthetic enzyme, 24-dehydrocholesterol reductase (DHCR24), which is defective in the hereditary developmental disease desmosterolosis.
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Affiliation(s)
- Anika V Prabhu
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Winnie Luu
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia
| | - Andrew J Brown
- School of Biotechnology and Biomolecular Sciences, The University of New South Wales, Sydney, NSW, 2052, Australia.
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21
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Accumulation of specific sterol precursors targets a MAP kinase cascade mediating cell-cell recognition and fusion. Proc Natl Acad Sci U S A 2016; 113:11877-11882. [PMID: 27708165 DOI: 10.1073/pnas.1610527113] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Sterols are vital components of eukaryotic cell membranes. Defects in sterol biosynthesis, which result in the accumulation of precursor molecules, are commonly associated with cellular disorders and disease. However, the effects of these sterol precursors on the metabolism, signaling, and behavior of cells are only poorly understood. In this study, we show that the accumulation of only ergosterol precursors with a conjugated double bond in their aliphatic side chain specifically disrupts cell-cell communication and fusion in the fungus Neurospora crassa Genetically identical germinating spores of this fungus undergo cell-cell fusion, thereby forming a highly interconnected supracellular network during colony initiation. Before fusion, the cells use an unusual signaling mechanism that involves the coordinated and alternating switching between signal sending and receiving states of the two fusion partners. Accumulation of only ergosterol precursors with a conjugated double bond in their aliphatic side chain disrupts this coordinated cell-cell communication and suppresses cell fusion. These specific sterol precursors target a single ERK-like mitogen-activated protein (MAP) kinase (MAK-1)-signaling cascade, whereas a second MAP kinase pathway (MAK-2), which is also involved in cell fusion, is unaffected. These observations indicate that a minor specific change in sterol structure can exert a strong detrimental effect on a key signaling pathway of the cell, resulting in the absence of cell fusion.
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22
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Liver-Specific Deletion of SRSF2 Caused Acute Liver Failure and Early Death in Mice. Mol Cell Biol 2016; 36:1628-38. [PMID: 27022105 DOI: 10.1128/mcb.01071-15] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Accepted: 03/21/2016] [Indexed: 12/21/2022] Open
Abstract
The liver performs a variety of unique functions critical for metabolic homeostasis. Here, we show that mice lacking the splicing factor SRSF2 but not SRSF1 in hepatocytes have severe liver pathology and biochemical abnormalities. Histological analyses revealed generalized hepatitis with the presence of ballooned hepatocytes and evidence of fibrosis. Molecular analysis demonstrated that SRSF2 governs splicing of multiple genes involved in the stress-induced cell death pathway in the liver. More importantly, SRSF2 also functions as a potent transcription activator, required for efficient expression of transcription factors mainly responsible for energy homeostasis and bile acid metabolism in the liver. Consistent with the effects of SRSF2 in gene regulation, accumulation of total cholesterol and bile acids was prominently observed in the mutant liver, followed by enhanced generation of reactive oxygen species and increased endoplasmic reticulum stress, as revealed by biochemical and ultrastructural analyses. Taking these observations together, inactivation of SRSF2 in liver caused dysregulated splicing events and hepatic metabolic disorders, which trigger endoplasmic reticulum stress, oxidative stress, and finally liver failure.
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23
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Nakamoto M, Schmit AC, Heintz D, Schaller H, Ohta D. Diversification of sterol methyltransferase enzymes in plants and a role for β-sitosterol in oriented cell plate formation and polarized growth. THE PLANT JOURNAL : FOR CELL AND MOLECULAR BIOLOGY 2015; 84:860-74. [PMID: 26426526 DOI: 10.1111/tpj.13043] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/14/2015] [Revised: 09/16/2015] [Accepted: 09/18/2015] [Indexed: 05/06/2023]
Abstract
Phytosterols are classified into C24-ethylsterols and C24-methylsterols according to the different C24-alkylation levels conferred by two types of sterol methyltransferases (SMTs). The first type of SMT (SMT1) is widely conserved, whereas the second type (SMT2) has diverged in charophytes and land plants. The Arabidopsis smt2 smt3 mutant is defective in the SMT2 step, leading to deficiency in C24-ethylsterols while the C24-methylsterol pathway is unchanged. smt2 smt3 plants exhibit severe dwarfism and abnormal development throughout their life cycle, with irregular cell division followed by collapsed cell files. Preprophase bands are occasionally formed in perpendicular directions in adjacent cells, and abnormal phragmoplasts with mislocalized KNOLLE syntaxin and tubulin are observed. Defects in auxin-dependent processes are exemplified by mislocalizations of the PIN2 auxin efflux carrier due to disrupted cell division and failure to distribute PIN2 asymmetrically after cytokinesis. Although endocytosis of PIN2-GFP from the plasma membrane (PM) is apparently unaffected in smt2 smt3, strong inhibition of the endocytic recycling is associated with a remarkable reduction in the level of PIN2-GFP on the PM. Aberrant localization of the cytoplasmic linker associated protein (CLASP) and microtubules is implicated in the disrupted endocytic recycling in smt2 smt3. Exogenous C24-ethylsterols partially recover lateral root development and auxin distribution in smt2 smt3 roots. These results indicate that C24-ethylsterols play a crucial role in division plane determination, directional auxin transport, and polar growth. It is proposed that the divergence of SMT2 genes together with the ability to produce C24-ethylsterols were critical events to achieve polarized growth in the plant lineage.
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Affiliation(s)
- Masatoshi Nakamoto
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 599-8531, Sakai, Japan
| | - Anne-Catherine Schmit
- Institut de Biologie Moléculaire des Plantes, CNRS, UPR2357, Conventionné Avec l'Université de Strasbourg, 67084, Strasbourg, France
| | - Dimitri Heintz
- Institut de Biologie Moléculaire des Plantes, CNRS, UPR2357, Conventionné Avec l'Université de Strasbourg, 67084, Strasbourg, France
| | - Hubert Schaller
- Institut de Biologie Moléculaire des Plantes, CNRS, UPR2357, Conventionné Avec l'Université de Strasbourg, 67084, Strasbourg, France
| | - Daisaku Ohta
- Graduate School of Life and Environmental Sciences, Osaka Prefecture University, 599-8531, Sakai, Japan
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24
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Yamauchi Y, Yokoyama S, Chang TY. ABCA1-dependent sterol release: sterol molecule specificity and potential membrane domain for HDL biogenesis. J Lipid Res 2015; 57:77-88. [PMID: 26497474 DOI: 10.1194/jlr.m063784] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2015] [Indexed: 01/28/2023] Open
Abstract
Mammalian cells synthesize various sterol molecules, including the C30 sterol, lanosterol, as cholesterol precursors in the endoplasmic reticulum. The build-up of precursor sterols, including lanosterol, displays cellular toxicity. Precursor sterols are found in plasma HDL. How these structurally different sterols are released from cells is poorly understood. Here, we show that newly synthesized precursor sterols arriving at the plasma membrane (PM) are removed by extracellular apoA-I in a manner dependent on ABCA1, a key macromolecule for HDL biogenesis. Analysis of sterol molecules by GC-MS and tracing the fate of radiolabeled acetate-derived sterols in normal and mutant Niemann-Pick type C cells reveal that ABCA1 prefers newly synthesized sterols, especially lanosterol, as the substrates before they are internalized from the PM. We also show that ABCA1 resides in a cholesterol-rich membrane domain resistant to the mild detergent, Brij 98. Blocking ACAT activity increases the cholesterol contents of this domain. Newly synthesized C29/C30 sterols are transiently enriched within this domain, but rapidly disappear from this domain with a half-life of less than 1 h. Our work shows that substantial amounts of precursor sterols are transported to a certain PM domain and are removed by the ABCA1-dependent pathway.
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Affiliation(s)
- Yoshio Yamauchi
- Department of Biochemistry II, Nagoya University Graduate School of Medicine, Nagoya 466-8550, Japan Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
| | - Shinji Yokoyama
- Nutritional Health Science Research Center and Department of Food and Nutritional Sciences, Chubu University, Kasugai 487-8501, Japan
| | - Ta-Yuan Chang
- Department of Biochemistry, Geisel School of Medicine at Dartmouth, Hanover, NH 03755
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25
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Computational model for monitoring cholesterol metabolism. SYSTEMS AND SYNTHETIC BIOLOGY 2015; 8:307-11. [PMID: 26396654 DOI: 10.1007/s11693-014-9152-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/02/2014] [Revised: 07/10/2014] [Accepted: 07/21/2014] [Indexed: 10/25/2022]
Abstract
A non-deterministic finite automaton is designed to observe the cholesterol metabolism with the states of acceptance and rejection. The acceptance state of the automaton depicts the normal level of metabolism and production of good cholesterol as an end product. The rejection state of this machine shows the inhibition of enzymatic activity in cholesterol synthesis and removal of free fatty acids. The deficiency in human cholesterol metabolism pathway results in abnormal accumulation of cholesterol in plasma, arterial tissues leading to diseases such as hypercholesterolemia, atherosclerosis respectively and formation of gallstones. The designed machine can be used to monitor the cholesterol metabolism at molecular level through regulation of enzymes involved in the biosynthesis and metabolism of cholesterol for the treatment of diseases incident due to the respective metabolic disorder. In addition, an algorithm for this machine has been developed to compare the programmed string with the given string. This study demonstrates the construction of a machine that is used for the development of molecular targeted therapy for the disorders in cholesterol metabolism.
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26
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Hernández A, Serrano-Bueno G, Perez-Castiñeira JR, Serrano A. 8-Dehydrosterols induce membrane traffic and autophagy defects through V-ATPase dysfunction in Saccharomyces cerevisae. BIOCHIMICA ET BIOPHYSICA ACTA-MOLECULAR CELL RESEARCH 2015; 1853:2945-56. [PMID: 26344037 DOI: 10.1016/j.bbamcr.2015.09.001] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/27/2015] [Accepted: 09/01/2015] [Indexed: 12/11/2022]
Abstract
8-Dehydrosterols are present in a wide range of biologically relevant situations, from human rare diseases to amine fungicide-treated fungi and crops. However, the molecular bases of their toxicity are still obscure. We show here that 8-dehydrosterols, but not other sterols, affect yeast vacuole acidification through V-ATPases. Moreover, erg2Δ cells display reductions in proton pumping rates consistent with ion-transport uncoupling in vitro. Concomitantly, subunit Vph1p shows conformational changes in the presence of 8-dehydrosterols. Expression of a plant vacuolar H(+)-pumping pyrophosphatase as an alternative H(+)-pump relieves Vma(-)-like phenotypes in erg2Δ-derived mutant cells. As a consequence of these acidification defects, endo- and exo-cytic traffic deficiencies that can be alleviated with a H(+)-pumping pyrophosphatase are also observed. Despite their effect on membrane traffic, 8-dehydrosterols do not induce endoplasmic reticulum stress or assembly defects on the V-ATPase. Autophagy is a V-ATPase dependent process and erg2Δ mutants accumulate autophagic bodies under nitrogen starvation similar to Vma(-) mutants. In contrast to classical Atg(-) mutants, this defect is not accompanied by impairment of traffic through the CVT pathway, processing of Pho8Δ60p, GFP-Atg8p localisation or difficulties to survive under nitrogen starvation conditions, but it is concomitant to reduced vacuolar protease activity. All in all, erg2Δ cells are autophagy mutants albeit some of their phenotypic features differ from classical Atg(-) defective cells. These results may pave the way to understand the aetiology of sterol-related diseases, the cytotoxic effect of amine fungicides, and may explain the tolerance to these compounds observed in plants.
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Affiliation(s)
- Agustín Hernández
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda Américo Vespucio 48, 41092 Sevilla, Spain.
| | - Gloria Serrano-Bueno
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda Américo Vespucio 48, 41092 Sevilla, Spain
| | - José Román Perez-Castiñeira
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda Américo Vespucio 48, 41092 Sevilla, Spain
| | - Aurelio Serrano
- Instituto de Bioquímica Vegetal y Fotosíntesis, Universidad de Sevilla-CSIC, Avda Américo Vespucio 48, 41092 Sevilla, Spain.
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27
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Róg T, Pöyry S, Vattulainen I. Building Synthetic Sterols Computationally - Unlocking the Secrets of Evolution? Front Bioeng Biotechnol 2015; 3:121. [PMID: 26347865 PMCID: PMC4543873 DOI: 10.3389/fbioe.2015.00121] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2015] [Accepted: 08/07/2015] [Indexed: 01/28/2023] Open
Abstract
Cholesterol is vital in regulating the physical properties of animal cell membranes. While it remains unclear what renders cholesterol so unique, it is known that other sterols are less capable in modulating membrane properties, and there are membrane proteins whose function is dependent on cholesterol. Practical applications of cholesterol include its use in liposomes in drug delivery and cosmetics, cholesterol-based detergents in membrane protein crystallography, its fluorescent analogs in studies of cholesterol transport in cells and tissues, etc. Clearly, in spite of their difficult synthesis, producing the synthetic analogs of cholesterol is of great commercial and scientific interest. In this article, we discuss how synthetic sterols non-existent in nature can be used to elucidate the roles of cholesterol’s structural elements. To this end, we discuss recent atomistic molecular dynamics simulation studies that have predicted new synthetic sterols with properties comparable to those of cholesterol. We also discuss more recent experimental studies that have vindicated these predictions. The paper highlights the strength of computational simulations in making predictions for synthetic biology, thereby guiding experiments.
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Affiliation(s)
- Tomasz Róg
- Department of Physics, Tampere University of Technology , Tampere , Finland
| | - Sanja Pöyry
- Department of Physics, Tampere University of Technology , Tampere , Finland
| | - Ilpo Vattulainen
- Department of Physics, Tampere University of Technology , Tampere , Finland ; MEMPHYS-Center for Biomembrane Physics, University of Southern Denmark , Odense , Denmark
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28
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Altunayar C, Sahin I, Kazanci N. A comparative study of the effects of cholesterol and desmosterol on zwitterionic DPPC model membranes. Chem Phys Lipids 2015; 188:37-45. [DOI: 10.1016/j.chemphyslip.2015.03.006] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2015] [Revised: 03/24/2015] [Accepted: 03/26/2015] [Indexed: 10/23/2022]
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29
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Bellezza I, Gatticchi L, del Sordo R, Peirce MJ, Sidoni A, Roberti R, Minelli A. The loss of Tm7sf gene accelerates skin papilloma formation in mice. Sci Rep 2015; 5:9471. [PMID: 25804527 PMCID: PMC4372794 DOI: 10.1038/srep09471] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/09/2014] [Accepted: 02/16/2015] [Indexed: 01/04/2023] Open
Abstract
The 3β-hydroxysterol Δ14-reductase, encoded by the Tm7sf2 gene, is an enzyme involved in cholesterol biosynthesis. Cholesterol and its derivatives control epidermal barrier integrity and are protective against environmental insults. To determine the role of the gene in skin cholesterol homeostasis, we applied 12-o-tetradecanoylphorbol-13-acetate (TPA) to the skin of Tm7sf2+/+ and Tm7sf2-/- mice. TPA increased skin cholesterol levels by inducing de novo synthesis and up-take only in Tm7sf2+/+ mouse, confirming that the gene maintains cholesterol homeostasis under stress conditions. Cholesterol sulfate, one of the major players in skin permeability, was doubled by TPA treatment in the skin of wild-type animals but this response was lost in Tm7sf2-/- mice. The expression of markers of epidermal differentiation concomitant with farnesoid-X-receptor and p38 MAPK activation were also disrupted in Tm7sf2-/- mice. We then subjected Tm7sf2+/+ and Tm7sf2-/- mice to a classical two-stage skin carcinogenesis protocol. We found that the loss of Tm7sf2 increased incidence and multiplicity of skin papillomas. Interestingly, the null genotype showed reduced expression of nur77, a gene associated with resistance to neoplastic transformation. In conclusion, the loss of Tm7sf2 alters the expression of proteins involved in epidermal differentiation by reducing the levels of cholesterol sulfate.
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Affiliation(s)
- I Bellezza
- Dipartimento di Medicina Sperimentale, Università di Perugia, Polo Unico Sant'Andrea delle Fratte, p.le Gambuli, Perugia, 06132; Italia
| | - L Gatticchi
- Dipartimento di Medicina Sperimentale, Università di Perugia, Polo Unico Sant'Andrea delle Fratte, p.le Gambuli, Perugia, 06132; Italia
| | - R del Sordo
- Dipartimento di Medicina Sperimentale, Università di Perugia, Polo Unico Sant'Andrea delle Fratte, p.le Gambuli, Perugia, 06132; Italia
| | - M J Peirce
- Dipartimento di Medicina Sperimentale, Università di Perugia, Polo Unico Sant'Andrea delle Fratte, p.le Gambuli, Perugia, 06132; Italia
| | - A Sidoni
- Dipartimento di Medicina Sperimentale, Università di Perugia, Polo Unico Sant'Andrea delle Fratte, p.le Gambuli, Perugia, 06132; Italia
| | - R Roberti
- Dipartimento di Medicina Sperimentale, Università di Perugia, Polo Unico Sant'Andrea delle Fratte, p.le Gambuli, Perugia, 06132; Italia
| | - A Minelli
- Dipartimento di Medicina Sperimentale, Università di Perugia, Polo Unico Sant'Andrea delle Fratte, p.le Gambuli, Perugia, 06132; Italia
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Bianconi SE, Cross JL, Wassif CA, Porter FD. Pathogenesis, Epidemiology, Diagnosis and Clinical Aspects of Smith-Lemli-Opitz Syndrome. Expert Opin Orphan Drugs 2015; 3:267-280. [PMID: 25734025 PMCID: PMC4343216 DOI: 10.1517/21678707.2015.1014472] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
INTRODUCTION Smith-Lemli-Opitz Syndrome (SLOS) is a malformation syndrome inherited in an autosomal recessive fashion. It is due to a metabolic defect in the conversion of 7-dehydrocholesterol to cholesterol, which leads to an accumulation of 7-dehydrocholesterol and frequently a deficiency of cholesterol. The syndrome is characterized by typical dysmorphic facial features, multiple malformations, and intellectual disability. AREAS COVERED In this paper we provide an overview of the clinical phenotype and discuss how the manifestations of the syndrome vary depending on the age of the patients. We then explore the underlying biochemical defect and pathophysiological alterations that may contribute to the many disease manifestations. Subsequently we explore the epidemiology and succinctly discuss population genetics as they relate to SLOS. The next section presents the diagnostic possibilities. Thereafter, the treatment and management as is standard of care are presented. EXPERT OPINION Even though the knowledge of the underlying molecular mutations and the biochemical alterations is being rapidly accumulated, there is currently no efficacious therapy addressing neurological dysfunction. We discuss the difficulty of treating this disorder, which manifests as a combination of a malformation syndrome and an inborn error of metabolism. A very important factor in developing new therapies is the need to rigorously establish efficacy in controlled trials.
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Affiliation(s)
- Simona E Bianconi
- National Institute of Child Health and Human Development, Program in Developmental Endocrinology and Genetics, Section on Molecular Dysmorphology, 10 Center Drive, Bld 10 Rm 9D42, Bethesda, MD 20892,
| | - Joanna L Cross
- National Institute of Child Health and Human Development, Program in Developmental Endocrinology and Genetics, Section on Molecular Dysmorphology, 10 Center Drive, Bld 10 CRC, Rm 1-3288, Bethesda, MD 20892
| | - Christopher A Wassif
- National Institute of Child Health and Human Development, Program in Developmental Endocrinology and Genetics, Section on Molecular Dysmorphology, 10 Center Drive, Bld 10 CRC, Rm 1-3288, Bethesda, MD 20892
| | - Forbes D Porter
- National Institute of Child Health and Human Development, Program in Developmental Endocrinology and Genetics, Section on Molecular Dysmorphology, 10 Center Drive, Bld 10, CRC, Rm 2571, Bethesda, MD 20892,
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Abstract
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7-Dehydrocholesterol (7-DHC) is the
most oxidizable lipid molecule
reported to date, with a propagation rate constant for free radical
peroxidation that is 200 times that of cholesterol. To better understand
the high reactivity of 7-DHC and elucidate the reaction mechanism,
we synthesized conjugated and skipped nonconjugated cholestadienols
that would give one of the two putative pentadienyl-radical intermediates
formed in 7-DHC peroxidation. The additional dienols include 6,8(9)-dienol,
5,8(14)-dienol, 6,8(14)-dienol, and the biologically important 8-dehydrocholesterol
(8-DHC; 5,8(9)-dienol). We found that all of the dienols are significantly
(at least 40 times) more reactive than cholesterol. Among them, dienols
leading to the formation of the pentadienyl radical in ring B (termed endo-B) of the sterol are more reactive than
those leading to the pentadienyl radical spanning rings B and C (termed exo-B). By comparing the oxysterol profile
formed from 7-DHC and those formed from 8-DHC and 5,8(14)-dienol,
products formed from abstraction of the hydrogen atoms at C-9 and
C-14 (H-9 or H-14 mechanism) were
clearly differentiated. When the oxidation was carried out in the
presence of the good hydrogen atom donor α-tocopherol, the oxysterol
profile of 7-DHC peroxidation differed distinctly from the profile
observed in the absence of the antioxidant and resembles more closely
the profile observed in biological systems. This study suggests that
oxidative stress and the accumulation of oxysterols should be considered
as two key factors in cholesterol biosynthesis or metabolism disorders,
where dienyl sterol intermediates are accumulated.
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Affiliation(s)
- Libin Xu
- Department of Chemistry and Vanderbilt Institute of Chemical Biology, Vanderbilt University , Nashville, Tennessee 37235, United States
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32
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Kanungo S, Soares N, He M, Steiner RD. Sterol metabolism disorders and neurodevelopment-an update. ACTA ACUST UNITED AC 2014; 17:197-210. [PMID: 23798009 DOI: 10.1002/ddrr.1114] [Citation(s) in RCA: 57] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/17/2012] [Indexed: 12/28/2022]
Abstract
Cholesterol has numerous quintessential functions in normal cell physiology, as well as in embryonic and postnatal development. It is a major component of cell membranes and myelin, and is a precursor of steroid hormones and bile acids. The development of the blood brain barrier likely around 12-18 weeks of human gestation makes the developing embryonic/fetal brain dependent on endogenous cholesterol synthesis. Known enzyme defects along the cholesterol biosynthetic pathway result in a host of neurodevelopmental and behavioral findings along with CNS structural anomalies. In this article, we review sterol synthesis disorders in the pre- and post-squalene pathway highlighting neurodevelopmental aspects that underlie the clinical presentations and course of Smith-Lemli-Opitz Syndrome (SLOS), mevalonic aciduria (MVA) or the milder version hyper-immunoglobulinemia D and periodic fever syndrome (HIDS), Antley-Bixler syndrome with genital anomalies and disordered steroidogenesis (ABS1), congenital hemidysplasia with icthyosiform nevus and limb defects (CHILD) syndrome, CK syndrome, sterol C4 methyl oxidase (SC4MOL) deficiency, X-linked dominant chondrodysplasia punctata 2(CDPX2)/ Conradi Hunermann syndrome, lathosterolosis and desmosterolosis, We also discuss current controversies and share thoughts on future directions in the field.
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Affiliation(s)
- Shibani Kanungo
- Department of Pediatrics, University of Pittsburgh Medical Center, Pennsylvania, USA
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33
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Lew PP, Ngai SS, Hamidi R, Cho JK, Birnbaum RA, Peng DH, Varma RK. Imaging of Disorders Affecting the Bone and Skin. Radiographics 2014; 34:197-216. [DOI: 10.1148/rg.341125112] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
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34
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van Gelder MM, van Rooij IA, de Jong-van den Berg LT, Roeleveld N. Teratogenic Mechanisms Associated with Prenatal Medication Exposure. Therapie 2014; 69:13-24. [DOI: 10.2515/therapie/2014003] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Accepted: 10/18/2013] [Indexed: 12/31/2022]
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35
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Krojer M, Müller C, Bracher F. Steroidomimetic Aminomethyl Spiroacetals as Novel Inhibitors of the Enzyme Δ8,7-Sterol Isomerase in Cholesterol Biosynthesis. Arch Pharm (Weinheim) 2013; 347:108-22. [DOI: 10.1002/ardp.201300296] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2013] [Revised: 09/16/2013] [Accepted: 09/17/2013] [Indexed: 11/10/2022]
Affiliation(s)
- Melanie Krojer
- Department of Pharmacy - Center for Drug Research; Ludwig-Maximilians-University of Munich; Munich Germany
| | - Christoph Müller
- Department of Pharmacy - Center for Drug Research; Ludwig-Maximilians-University of Munich; Munich Germany
| | - Franz Bracher
- Department of Pharmacy - Center for Drug Research; Ludwig-Maximilians-University of Munich; Munich Germany
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36
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Tu C, Li J, Jiang X, Sheflin LG, Pfeffer BA, Behringer M, Fliesler SJ, Qu J. Ion-current-based proteomic profiling of the retina in a rat model of Smith-Lemli-Opitz syndrome. Mol Cell Proteomics 2013; 12:3583-98. [PMID: 23979708 PMCID: PMC3861709 DOI: 10.1074/mcp.m113.027847] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2013] [Revised: 08/21/2013] [Indexed: 12/26/2022] Open
Abstract
Smith-Lemli-Opitz syndrome (SLOS) is one of the most common recessive human disorders and is characterized by multiple congenital malformations as well as neurosensory and cognitive abnormalities. A rat model of SLOS has been developed that exhibits progressive retinal degeneration and visual dysfunction; however, the molecular events underlying the degeneration and dysfunction remain poorly understood. Here, we employed a well-controlled, ion-current-based approach to compare retinas from the SLOS rat model to retinas from age- and sex-matched control rats (n = 5/group). Retinas were subjected to detergent extraction and subsequent precipitation and on-pellet-digestion procedures and then were analyzed on a long, heated column (75 cm, with small particles) with a 7-h gradient. The high analytical reproducibility of the overall proteomics procedure enabled reliable expression profiling. In total, 1,259 unique protein groups, ~40% of which were membrane proteins, were quantified under highly stringent criteria, including a peptide false discovery rate of 0.4%, with high quality ion-current data (e.g. signal-to-noise ratio ≥ 10) obtained independently from at least two unique peptides for each protein. The ion-current-based strategy showed greater quantitative accuracy and reproducibility over a parallel spectral counting analysis. Statistically significant alterations of 101 proteins were observed; these proteins are implicated in a variety of biological processes, including lipid metabolism, oxidative stress, cell death, proteolysis, visual transduction, and vesicular/membrane transport, consistent with the features of the associated retinal degeneration in the SLOS model. Selected targets were further validated by Western blot analysis and correlative immunohistochemistry. Importantly, although photoreceptor cell death was validated by TUNEL analysis, Western blot and immunohistochemical analyses suggested a caspase-3-independent pathway. In total, these results provide compelling new evidence implicating molecular changes beyond the initial defect in cholesterol biosynthesis in this retinal degeneration model, and they might have broader implications with respect to the pathobiological mechanism underlying SLOS.
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Affiliation(s)
- Chengjian Tu
- From the ‡Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, New York 14260
- §New York State Center of Excellence in Bioinformatics and Life Sciences, 701 Ellicott Street, Buffalo, New York 14203
| | - Jun Li
- From the ‡Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, New York 14260
- §New York State Center of Excellence in Bioinformatics and Life Sciences, 701 Ellicott Street, Buffalo, New York 14203
| | - Xiaosheng Jiang
- From the ‡Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, New York 14260
- §New York State Center of Excellence in Bioinformatics and Life Sciences, 701 Ellicott Street, Buffalo, New York 14203
| | - Lowell G. Sheflin
- ¶Research Service, Veterans Administration Western New York Healthcare System, Buffalo, New York 14215
| | - Bruce A. Pfeffer
- ‖Departments of Ophthalmology and Biochemistry, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York 14260
- **SUNY Eye Institute, Buffalo, New York 14215
| | - Matthew Behringer
- ‖Departments of Ophthalmology and Biochemistry, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York 14260
| | - Steven J. Fliesler
- ¶Research Service, Veterans Administration Western New York Healthcare System, Buffalo, New York 14215
- ‖Departments of Ophthalmology and Biochemistry, School of Medicine and Biomedical Sciences, University at Buffalo, State University of New York, Buffalo, New York 14260
- **SUNY Eye Institute, Buffalo, New York 14215
| | - Jun Qu
- From the ‡Department of Pharmaceutical Sciences, School of Pharmacy and Pharmaceutical Sciences, University at Buffalo, State University of New York, Buffalo, New York 14260
- §New York State Center of Excellence in Bioinformatics and Life Sciences, 701 Ellicott Street, Buffalo, New York 14203
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37
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Seeger MA, Paller AS. The role of abnormalities in the distal pathway of cholesterol synthesis in the Congenital Hemidysplasia with Ichthyosiform erythroderma and Limb Defects (CHILD) syndrome. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:345-52. [PMID: 24060582 DOI: 10.1016/j.bbalip.2013.09.006] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2013] [Revised: 09/09/2013] [Accepted: 09/12/2013] [Indexed: 12/28/2022]
Abstract
CHILD syndrome (Congenital Hemidysplasia with Ichthyosiform erythroderma and Limb Defects) is a rare X-linked dominant ichthyotic disorder. CHILD syndrome results from loss of function mutations in the NSDHL gene, which leads to inhibition of cholesterol synthesis and accumulation of toxic metabolic intermediates in affected tissues. The CHILD syndrome skin is characterized by plaques topped by waxy scales and a variety of developmental defects in extracutaneous tissues, particularly limb hypoplasia or aplasia. Strikingly, these alterations are commonly segregated to either the right or left side of the body midline with little to no manifestations on the ipsilateral side. By understanding the underlying disease mechanism of CHILD syndrome, a pathogenesis-based therapy has been developed that successfully reverses the CHILD syndrome skin phenotype and has potential applications to the treatment of other ichthyoses. This article is part of a Special Issue entitled The Important Role of Lipids in the Epidermis and their Role in the Formation and Maintenance of the Cutaneous Barrier. Guest Editors: Kenneth R. Feingold and Peter Elias.
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Affiliation(s)
- Mark A Seeger
- Departments of Dermatology and Pediatrics, The Feinberg School of Medicine, Northwestern University, Chicago, IL, USA
| | - Amy S Paller
- Departments of Dermatology and Pediatrics, The Feinberg School of Medicine, Northwestern University, Chicago, IL, USA.
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38
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Cañueto J, Girós M, González-Sarmiento R. The role of the abnormalities in the distal pathway of cholesterol biosynthesis in the Conradi-Hünermann-Happle syndrome. Biochim Biophys Acta Mol Cell Biol Lipids 2013; 1841:336-44. [PMID: 24036494 DOI: 10.1016/j.bbalip.2013.09.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2013] [Revised: 09/02/2013] [Accepted: 09/04/2013] [Indexed: 11/28/2022]
Abstract
Conradi-Hünermann-Happle syndrome (CDPX2, OMIM 302960) is an inherited X-linked dominant variant of chondrodysplasia punctata (CP) caused by mutations in one gene of the distal pathway of cholesterol biosynthesis. It exhibits intense phenotypic variation and primarily affects the skin, bones and eyes. The ichthyosis following Blaschko's lines, chondrodysplasia punctata and cataracts are the typical clinical findings. The cardinal biochemical features are an increase in 8(9)-cholestenol and 8-dehydrocholesterol (8DHC), which suggest a deficiency in 3β-hydroxysteroid-Δ8,Δ7-isomerase, also called emopamil binding protein (EBP). The EBP gene is located on the short arm of the X chromosome (Xp11.22-p11.23) and encodes a 230 amino acid protein with dual function. Explaining the clinical phenotype in CDPX2 implies an understanding of both the genetics and biochemical features of this disease. CDPX2 displays an X-linked dominant pattern of inheritance, which is responsible for the distribution of lesions in some tissues. The clinical phenotype in CDPX2 results directly from impairment in cholesterol biosynthesis, and indirectly from abnormalities in the hedgehog signaling protein pathways. This article is part of a Special Issue entitled The Important Role of Lipids in the Epidermis and their Role in the Formation and Maintenance of the Cutaneous Barrier. Guest Editors: Kenneth R. Feingold and Peter Elias.
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Affiliation(s)
- Javier Cañueto
- Department of Dermatology, University Hospital of Salamanca, Paseo San Vicente 58-182, 37007 Salamanca, Spain; IBSAL (Instituto de Investigación Biosanitaria de Salamanca), Spain.
| | - Marisa Girós
- Seccio Errors Congenits del Metabolisme, Servei de Bioquímica Clínica i Genética Molecular, Hospital Clinic Barcelona, Barcelona, Spain
| | - Rogelio González-Sarmiento
- IBSAL (Instituto de Investigación Biosanitaria de Salamanca), Spain; Molecular Medicine Unit, Faculty of Medicine, University of Salamanca, Campus Miguel de Unamuno S/N, Salamanca 37007, Spain; Laboratory 14, IBMCC-CSIC, University of Salamanca, Campus Miguel de Unamuno S/N, Salamanca 37007, Spain
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39
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Abstract
During the past 20 years, tremendous progress has been made in our understanding of the molecular basis of many genetic skin conditions. The translation of these laboratory findings into effective therapies for affected individuals has been slow, however, in large part due to the risk of carcinogenesis from random viral genomic integration and the lack of efficacy of topically applied genetic material and most proteins. As intervention at the gene level still appears remote for most genetic disorders, increased knowledge about the cellular and biochemical pathogenesis of disease allows specific targeting of pathways with existing and/or novel drugs and molecules. In contrast to the requirement for personalization of most gene-based approaches, pathogenesis-based therapy is pathway specific, and in theory, it should have broader applicability. In this chapter, we provide an overview of the pathoetiology of the various types of ichthyoses and demonstrate how a pathogenesis-based approach can potentially lead to innovative treatments for these conditions. Notably, this strategy has been successfully validated for the treatment of the rare X-linked dominant condition, CHILD syndrome, in which topical applications of cholesterol and lovastatin together to affected skin resulted in marked improvement of the skin phenotype.
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Affiliation(s)
- Joey E Lai-Cheong
- St John's Institute of Dermatology, King's College London, London, United Kingdom
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40
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Zafeiriou DI, Ververi A, Dafoulis V, Kalyva E, Vargiami E. Autism spectrum disorders: the quest for genetic syndromes. Am J Med Genet B Neuropsychiatr Genet 2013; 162B:327-66. [PMID: 23650212 DOI: 10.1002/ajmg.b.32152] [Citation(s) in RCA: 61] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/08/2011] [Accepted: 03/01/2013] [Indexed: 11/10/2022]
Abstract
Autism spectrum disorders (ASD) are a heterogeneous group of neurodevelopmental disabilities with various etiologies, but with a heritability estimate of more than 90%. Although the strong correlation between autism and genetic factors has been long established, the exact genetic background of ASD remains unclear. A number of genetic syndromes manifest ASD at higher than expected frequencies compared to the general population. These syndromes account for more than 10% of all ASD cases and include tuberous sclerosis, fragile X, Down, neurofibromatosis, Angelman, Prader-Willi, Williams, Duchenne, etc. Clinicians are increasingly required to recognize genetic disorders in individuals with ASD, in terms of providing proper care and prognosis to the patient, as well as genetic counseling to the family. Vice versa, it is equally essential to identify ASD in patients with genetic syndromes, in order to ensure correct management and appropriate educational placement. During investigation of genetic syndromes, a number of issues emerge: impact of intellectual disability in ASD diagnoses, identification of autistic subphenotypes and differences from idiopathic autism, validity of assessment tools designed for idiopathic autism, possible mechanisms for the association with ASD, etc. Findings from the study of genetic syndromes are incorporated into the ongoing research on autism etiology and pathogenesis; different syndromes converge upon common biological backgrounds (such as disrupted molecular pathways and brain circuitries), which probably account for their comorbidity with autism. This review paper critically examines the prevalence and characteristics of the main genetic syndromes, as well as the possible mechanisms for their association with ASD.
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41
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Cardoso M, Barbosa M, Serra D, Martins E, Fortuna A, Reis-Lima M, Bandeira A, Balreira A, Marques F. Living with inborn errors of cholesterol biosynthesis: lessons from adult patients. Clin Genet 2013; 85:184-8. [DOI: 10.1111/cge.12139] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2012] [Revised: 03/07/2013] [Accepted: 03/07/2013] [Indexed: 11/30/2022]
Affiliation(s)
- M.L. Cardoso
- Institute for Molecular and Cell Biology (IBMC); University of Porto; Porto Portugal
| | - M. Barbosa
- Gulbenkian Science Institute; Oeiras Portugal
- Medical Genetics Centre Jacinto Magalhães; Porto Portugal
| | - D. Serra
- Dermatology Department; Coimbra University Hospitals; Coimbra Portugal
| | - E. Martins
- Metabolic Unit; Porto Hospital Centre (CHP); Porto Portugal
| | - A. Fortuna
- Medical Genetics Centre Jacinto Magalhães; Porto Portugal
| | | | - A. Bandeira
- Metabolic Unit; Porto Hospital Centre (CHP); Porto Portugal
| | - A. Balreira
- Institute for Molecular and Cell Biology (IBMC); University of Porto; Porto Portugal
| | - F. Marques
- Institute for Molecular and Cell Biology (IBMC); University of Porto; Porto Portugal
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42
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König M, Müller C, Bracher F. Stereoselective synthesis of a new class of potent and selective inhibitors of human Δ8,7-sterol isomerase. Bioorg Med Chem 2013; 21:1925-43. [DOI: 10.1016/j.bmc.2013.01.041] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2012] [Revised: 01/10/2013] [Accepted: 01/14/2013] [Indexed: 10/27/2022]
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Meljon A, Watson GL, Wang Y, Shackleton CHL, Griffiths WJ. Analysis by liquid chromatography-mass spectrometry of sterols and oxysterols in brain of the newborn Dhcr7(Δ3-5/T93M) mouse: a model of Smith-Lemli-Opitz syndrome. Biochem Pharmacol 2013; 86:43-55. [PMID: 23500538 DOI: 10.1016/j.bcp.2013.03.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2013] [Revised: 02/28/2013] [Accepted: 03/01/2013] [Indexed: 10/27/2022]
Abstract
In this study the sterol and oxysterol profile of newborn brain from the Dhcr7(Δ3-5/T93M) mouse model of Smith-Lemli-Opitz syndrome (SLOS) has been investigated. This is a viable mouse model which is compound heterozygous containing one null allele and one T93M mutation on Dhcr7. We find the SLOS mouse has reduced levels of cholesterol and desmosterol and increased levels of 7- and 8-dehydrocholesterol and of 7- and 8-dehydrodesmosterol in brain compared to the wild type. The profile of enzymatically formed oxysterols in the SLOS mouse resembles that in the wild type but the level of 24S-hydroxycholesterol, the dominating cholesterol metabolite, is reduced in a similar proportion to that of cholesterol. A number of oxysterols abundant in the SLOS mouse are probably derived from 7-dehydrocholesterol, however, the mechanism of their formation is unclear.
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Affiliation(s)
- Anna Meljon
- Institute of Mass Spectrometry, College of Medicine, Swansea University, Singleton Park, Swansea SA2 8PP, UK
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44
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Abstract
Genetic defects in enzymes responsible for cholesterol biosynthesis have emerged as important causes of congenital dysmorphology and retardation syndromes. Cholesterol is an important constituent of the cell membrane of most eukaryotic cells, in myelin formation in the brain, spinal cord, and peripheral nervous system, and acts as the precursor for steroid hormones and bile acids. Finally, cholesterol has important interactions with proteins, which control embryonic development. To date, eight distinct inherited disorders have been linked to different defects in cholesterol biosynthesis. Two result from an enzyme defect in the pre-squalene segment of the pathway: the classical form of mevalonic aciduria and the hyperimmunoglobulinemia D syndrome, also known as Dutch-type periodic fever. Six defects in the post-squalene segment of the pathway include: Smith-Lemli-Opitz syndrome, two X-linked dominant inherited and male-lethal disorders, Conradi-Hünermann-Happle syndrome and congenital hemidysplasia with ichthyosiform erythroderma and limb defects (CHILD), and at least three extremely rare autosomal recessive disorders, Greenberg skeletal dysplasia, lathosterolosis, and desmosterolosis. All these inborn errors known to date have been linked to deficiency of specific enzymes on the basis of elevated levels of specific sterol intermediates in tissues of affected patients followed by demonstrating disease-causing mutations in the encoding genes. These cholesterol deficiency multiple malformation-retardation syndromes have clinical overlap. Besides psychomotor retardation, developmental delay, structural brain malformations, multiple congenital anomalies, microcephaly, and cataract, impaired cholesterol biosynthesis is associated with autism and other behavioral disorders.
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Affiliation(s)
- Petr Jira
- Department of Pediatrics, University Medical Centre Nijmegen, Nijmegen, The Netherlands.
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45
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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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Nowaczyk MJM, Irons MB. Smith-Lemli-Opitz syndrome: phenotype, natural history, and epidemiology. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2012; 160C:250-62. [PMID: 23059950 DOI: 10.1002/ajmg.c.31343] [Citation(s) in RCA: 93] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Smith-Lemli-Opitz syndrome (SLOS) is a congenital multiple anomaly/intellectual disability syndrome caused by a deficiency of cholesterol synthesis resulting from a deficiency of 7-dehydrocholesterol (7DHC) reductase encoded by DHCR7. SLOS is inherited in an autosomal recessive pattern. It is characterized by prenatal and postnatal growth retardation, microcephaly, a variable degree of intellectual disability that encompasses normal intelligence to severe intellectual deficiency, and multiple major and minor malformations. External malformations include distinctive facial features, cleft palate, postaxial polydactyly, 2-3 syndactyly of the toes, and underdeveloped external genitalia in males, while internal anomalies may affect every organ system. The clinical spectrum is wide, and rare individuals have been described with normal development and only minor malformations. The clinical diagnosis of SLOS is confirmed by demonstrating an abnormally elevated concentration of the cholesterol precursor, 7DHC, in serum or other tissues, or by the presence of two DHCR7 mutations. The enzymatic deficiency results in decreased cholesterol and increased 7DHC levels, both during embryonic development and after birth. The malformations found in SLOS may result from decreased cholesterol, increased 7DHC or a combination of these two factors. This review discusses the physical and behavioral phenotype of SLOS, the diagnostic approaches, the natural history from the prenatal period to adulthood, and current understanding of the pathophysiology of SLOS.
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Affiliation(s)
- Małgorzata J M Nowaczyk
- Department of Pathology and Molecular Medicine and Department of Pediatrics, McMaster University McMaster University Medical Centre, Room 3N16, 1200 Main Street West, Hamilton ON, Canada L8S 4J9.
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Diaz-Stransky A, Tierney E. Cognitive and behavioral aspects of Smith-Lemli-Opitz syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2012; 160C:295-300. [DOI: 10.1002/ajmg.c.31342] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Herman GE, Kratz L. Disorders of sterol synthesis: beyond Smith-Lemli-Opitz syndrome. AMERICAN JOURNAL OF MEDICAL GENETICS PART C-SEMINARS IN MEDICAL GENETICS 2012; 160C:301-21. [PMID: 23042573 DOI: 10.1002/ajmg.c.31340] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Since the discovery in 1993 that Smith-Lemli-Opitz syndrome (SLOS) is a disorder of cholesterol biosynthesis, human disorders associated with additional enzymes involved in the conversion of lanosterol to cholesterol have been identified. This review will focus primarily on the clinical aspects of these disorders, highlighting newly described syndromes, such as SC4MOL deficiency and CK syndrome. We will also provide clinical descriptions of additional cases for extremely rare disorders, such as desmosterolosis. We will compare and contrast the findings with those found in SLOS and briefly discuss possible mechanisms of disease pathogenesis.
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Affiliation(s)
- Gail E Herman
- Center for Molecular and Human Genetics, The Research Institute at Nationwide Children's Hospital, 700 Children's Dr. Rm W403, Columbus, OH 43205, USA.
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Shin GH, Veen M, Stahl U, Lang C. Overexpression of genes of the fatty acid biosynthetic pathway leads to accumulation of sterols in Saccharomyces cerevisiae. Yeast 2012; 29:371-83. [DOI: 10.1002/yea.2916] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2012] [Revised: 07/02/2012] [Accepted: 07/11/2012] [Indexed: 11/08/2022] Open
Affiliation(s)
| | | | - Ulf Stahl
- Technische Universität Berlin; Institut für Biotechnologie, FG Mikrobiologie und Genetik; Berlin; Germany
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Elias PM, Williams ML, Feingold KR. Abnormal barrier function in the pathogenesis of ichthyosis: therapeutic implications for lipid metabolic disorders. Clin Dermatol 2012; 30:311-22. [PMID: 22507046 DOI: 10.1016/j.clindermatol.2011.08.017] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Ichthyoses, including inherited disorders of lipid metabolism, display a permeability barrier abnormality in which the severity of the clinical phenotype parallels the prominence of the barrier defect. The pathogenesis of the cutaneous phenotype represents the consequences of the mutation for epidermal function, coupled with a "best attempt" by affected epidermis to generate a competent barrier in a terrestrial environment. A compromised barrier in normal epidermis triggers a vigorous set of metabolic responses that rapidly normalizes function, but ichthyotic epidermis, which is inherently compromised, only partially succeeds in this effort. Unraveling mechanisms that account for barrier dysfunction in the ichthyoses has identified multiple, subcellular, and biochemical processes that contribute to the clinical phenotype. Current treatment of the ichthyoses remains largely symptomatic: directed toward reducing scale or corrective gene therapy. Reducing scale is often minimally effective. Gene therapy is impeded by multiple pitfalls, including difficulties in transcutaneous drug delivery, high costs, and discomfort of injections. We have begun to use information about disease pathogenesis to identify novel, pathogenesis-based therapeutic strategies for the ichthyoses. The clinical phenotype often reflects not only a deficiency of pathway end product due to reduced-function mutations in key synthetic enzymes but often also accumulation of proximal, potentially toxic metabolites. As a result, depending upon the identified pathomechanism(s) for each disorder, the accompanying ichthyosis can be treated by topical provision of pathway product (eg, cholesterol), with or without a proximal enzyme inhibitor (eg, simvastatin), to block metabolite production. Among the disorders of distal cholesterol metabolism, the cutaneous phenotype in Congenital Hemidysplasia with Ichthyosiform Erythroderma and Limb Defects (CHILD syndrome) and X-linked ichthyosis reflect metabolite accumulation and deficiency of pathway product (ie, cholesterol). We validated this therapeutic approach in two CHILD syndrome patients who failed to improve with topical cholesterol alone, but cleared with dual treatment with cholesterol plus lovastatin. In theory, the ichthyoses in other inherited lipid metabolic disorders could be treated analogously. This pathogenesis (pathway)-driven approach possesses several inherent advantages: (1) it is mechanism-specific for each disorder; (2) it is inherently safe, because natural lipids and/or approved drugs often are utilized; and (3) it should be inexpensive, and therefore it could be used widely in the developing world.
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Affiliation(s)
- Peter M Elias
- Dermatology Service, Veterans Affairs Medical Center, 4150 Clement St, San Francisco, CA 94121, USA.
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