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7 dehydrocholesterol reductase

Željka Korade, Wei Liu, Emily B Warren, Kristan Armstrong, Ned A Porter, Christine Konradi
Cholesterol metabolism is vital for brain function. Previous work in cultured cells has shown that a number of psychotropic drugs inhibit the activity of 7-dehydrocholesterol reductase (DHCR7), an enzyme that catalyzes the final steps in cholesterol biosynthesis. This leads to the accumulation of 7-dehydrocholesterol (7DHC), a molecule that gives rise to oxysterols, vitamin D, and atypical neurosteroids. We examined levels of cholesterol and the cholesterol precursors desmosterol, lanosterol, 7DHC and its isomer 8-dehydrocholesterol (8DHC), in blood samples of 123 psychiatric patients on various antipsychotic and antidepressant drugs, and 85 healthy controls, to see if the observations in cell lines hold true for patients as well...
February 12, 2017: Schizophrenia Research
M Abboud, M S Rybchyn, R Rizk, D R Fraser, R S Mason
Studies on the determinants of vitamin D status have tended to concentrate on input - exposure to ultraviolet B radiation and the limited sources in food. Yet, vitamin D status, determined by circulating concentrations of 25-hydroxyvitamin D (25(OH)D), can vary quite markedly in groups of people with apparently similar inputs of vitamin D. There are small effects of polymorphisms in the genes for key proteins involved in vitamin D production and metabolism, including 7-dehydrocholesterol reductase, which converts 7-dehydrocholesterol, the precursor of vitamin D, to cholesterol, CYP2R1, the main 25-hydroxylase of vitamin D, GC, coding for the vitamin D binding protein which transports 25(OH)D and other metabolites in blood and CYP24A1, which 24-hydroxylates both 25(OH)D and the hormone, 1,25-dihydroxyvitamin D...
January 31, 2017: Photochemical & Photobiological Sciences
Anika V Prabhu, Winnie Luu, Dianfan Li, Laura J Sharpe, Andrew J Brown
The conversion of 7-dehydrocholesterol to cholesterol, the final step of cholesterol synthesis in the Kandutsch-Russell pathway, is catalyzed by the enzyme 7-dehydrocholesterol reductase (DHCR7). Homozygous or compound heterozygous mutations in DHCR7 lead to the developmental disease Smith-Lemli-Opitz syndrome, which can also result in fetal mortality, highlighting the importance of this enzyme in human development and survival. Besides serving as a substrate for DHCR7, 7-dehydrocholesterol is also a precursor of vitamin D via the action of ultraviolet light on the skin...
September 30, 2016: Progress in Lipid Research
Ayfer Aslan, Alp Ozgun Borcek, Selma Pamukcuoglu, M Kemali Baykaner
BACKGROUND: Smith-Lemli-Opitz Syndrome (SLOS) is a rare hereditary autosomal recessive disorder with broken cholesterol synthesis causing by 7-dehydrocholesterol reductase deficiency. Although the clinical features and pathogenesis is well-defined, it is unknown whether there is a relationship between SLOS and neoplastic processes, especially brain neoplasms. PURPOSE: We aimed to attract the attentions to any possibility of relation between SLOS and intracranial tumor development via a pediatric case with both intracranial high-grade neuroglial tumor and SLOS, and thus to contribute an additional data to the literature on togetherness of these two clinical conditions...
January 2017: Child's Nervous System: ChNS: Official Journal of the International Society for Pediatric Neurosurgery
Anika V Prabhu, Winnie Luu, Laura J Sharpe, Andrew J Brown
Cholesterol is essential for survival, but too much or too little can cause disease. Thus, cholesterol levels must be kept within close margins. 7-dehydrocholesterol reductase (DHCR7) is a terminal enzyme of cholesterol synthesis, and is essential for embryonic development. Largely, DHCR7 research is associated with the developmental disease Smith-Lemli-Opitz syndrome, which is caused by mutations in the DHCR7 gene. However, little is known about what regulates DHCR7 activity. Here we provide evidence that phosphorylation plays a role in controlling DHCR7 activity, which may provide a means to divert flux from cholesterol synthesis to vitamin D production...
January 2017: Journal of Steroid Biochemistry and Molecular Biology
Christopher A Wassif, Lisa Kratz, Susan E Sparks, Courtney Wheeler, Simona Bianconi, Andrea Gropman, Karim A Calis, Richard I Kelley, Elaine Tierney, Forbes D Porter
BACKGROUND: Smith-Lemli-Opitz syndrome (SLOS) is a multiple malformation/cognitive impairment syndrome characterized by the accumulation of 7-dehydrocholesterol, a precursor sterol of cholesterol. Simvastatin, a 3-hydroxy-3-methylglutaryl-coenzyme A reductase inhibitor that crosses the blood-brain barrier, has been proposed for the treatment of SLOS based on in vitro and in vivo studies suggesting that simvastatin increases the expression of hypomorphic DHCR7 alleles. METHODS: Safety and efficacy of simvastatin therapy in 23 patients with mild to typical SLOS were evaluated in a randomized, double-blind, placebo-controlled trial...
March 2017: Genetics in Medicine: Official Journal of the American College of Medical Genetics
M R Boland, N P Tatonetti
Mendelian diseases contain important biological information regarding developmental effects of gene mutations that can guide drug discovery and toxicity efforts. In this review, we focus on Smith-Lemli-Opitz syndrome (SLOS), a rare Mendelian disease characterized by compound heterozygous mutations in 7-dehydrocholesterol reductase (DHCR7) resulting in severe fetal deformities. We present a compilation of SLOS-inducing DHCR7 mutations and the geographic distribution of those mutations in healthy and diseased populations...
October 2016: Pharmacogenomics Journal
András Balajthy, Sándor Somodi, Zoltán Pethő, Mária Péter, Zoltán Varga, Gabriella P Szabó, György Paragh, László Vígh, György Panyi, Péter Hajdu
In vitro manipulation of membrane sterol level affects the regulation of ion channels and consequently certain cellular functions; however, a comprehensive study that confirms the pathophysiological significance of these results is missing. The malfunction of 7-dehydrocholesterol (7DHC) reductase in Smith-Lemli-Opitz syndrome (SLOS) leads to the elevation of the 7-dehydrocholesterol level in the plasma membrane. T lymphocytes were isolated from SLOS patients to assess the effect of the in vivo altered membrane sterol composition on the operation of the voltage-gated Kv1...
August 2016: Pflügers Archiv: European Journal of Physiology
Anke Doyon, Bettina Schmiedchen, Anja Sander, Aysun Bayazit, Ali Duzova, Nur Canpolat, Daniela Thurn, Karolis Azukaitis, Ali Anarat, Justine Bacchetta, Sevgi Mir, Rukshana Shroff, Ebru Yilmaz, Cengiz Candan, Markus Kemper, Michel Fischbach, Gerard Cortina, Günter Klaus, Matthias Wuttke, Anna Köttgen, Anette Melk, Uwe Querfeld, Franz Schaefer
BACKGROUND AND OBJECTIVES: Vitamin D deficiency is endemic in children with CKD. We sought to investigate the association of genetic disposition, environmental factors, vitamin D supplementation, and renal function on vitamin D status in children with CKD. DESIGN, SETTING, PARTICIPANTS, & MEASUREMENTS: Serum 25-hydroxy-vitamin D, 1,25-dihydroxy-vitamin D, and 24,25-dihydroxy-vitamin D concentrations were measured cross-sectionally in 500 children from 12 European countries with CKD stages 3-5...
July 7, 2016: Clinical Journal of the American Society of Nephrology: CJASN
Navdar Sever, Randall K Mann, Libin Xu, William J Snell, Carmen I Hernandez-Lara, Ned A Porter, Philip A Beachy
Cellular lipids are speculated to act as key intermediates in Hedgehog signal transduction, but their precise identity and function remain enigmatic. In an effort to identify such lipids, we pursued a Hedgehog pathway inhibitory activity that is particularly abundant in flagellar lipids of Chlamydomonas reinhardtii, resulting in the purification and identification of ergosterol endoperoxide, a B-ring oxysterol. A mammalian analog of ergosterol, 7-dehydrocholesterol (7-DHC), accumulates in Smith-Lemli-Opitz syndrome, a human genetic disease that phenocopies deficient Hedgehog signaling and is caused by genetic loss of 7-DHC reductase...
May 24, 2016: Proceedings of the National Academy of Sciences of the United States of America
Carolina Castro, Geneviève Corraze, Alexandre Firmino-Diógenes, Laurence Larroquet, Stéphane Panserat, Aires Oliva-Teles
The long-term effects on growth performance, body composition, plasma metabolites, liver and intestine glucose and lipid metabolism were assessed in gilthead sea bream juveniles fed diets without carbohydrates (CH-) or carbohydrate-enriched (20 % gelatinised starch, CH+) combined with two lipid sources (fish oil; or vegetable oil (VO)). No differences in growth performance among treatments were observed. Carbohydrate intake was associated with increased hepatic transcripts of glucokinase but not of 6-phosphofructokinase...
July 2016: British Journal of Nutrition
Stephanie M Cologna, Christine Shieh, Cynthia L Toth, Antony Cougnoux, Kathryn R Burkert, Simona E Bianconi, Christopher A Wassif, Forbes D Porter
Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive, multiple malformation syndrome with neurocognitive impairment. SLOS arises from mutations in the 7-dehydrocholesterol reductase gene which results in impaired enzymatic conversion of 7-dehydrocholesterol to cholesterol. In the current work, we sought to measure proteins that were altered in the cerebrospinal fluid from SLOS patients compared to pediatric controls. Using a multi-analyte antibody-based assay, we found that 12 proteins are altered in SLOS patients...
August 2016: American Journal of Medical Genetics. Part A
Hye-Young H Kim, Zeljka Korade, Keri A Tallman, Wei Liu, C David Weaver, Karoly Mirnics, Ned A Porter
A small library of pharmacologically active compounds (the NIH Clinical Collection) was assayed in Neuro2a cells to determine their effect on the last step in the biosynthesis of cholesterol, the transformation of 7-dehydrocholesterol (7-DHC) to cholesterol promoted by 7-dehydrocholesterol reductase, DHCR7. Of some 727 compounds in the NIH Clinical Collection, over 30 compounds significantly increased 7-DHC in Neuro2a cells when assayed at 1 μM. Active compounds that increased 7-DHC with a Z-score of +3 or greater generally gave rise to modest decreases in desmosterol and increases in lanosterol levels...
May 16, 2016: Chemical Research in Toxicology
Wen-lin Xiao, Dai-zun Zhang, Hong Xu, Cui-zhu Zhuang
The aim of this study was to investigate the effect of the 7-dehydrocholesterol reductase (Dhcr7) gene and identify signaling pathways involved in regulation of embryonic palatogenesis. The expression of Dhcr7 and its protein product were examined during murine normal embryonic palatogenesis via a reverse transcription polymerase chain reaction (RT-PCR) and Western blot (WB). RNA interference (RNAi) technology was used to inhibit Dhcr7 expression in a palatal shelf culture in vitro. The effects of Dhcr7 on palatogenesis and palatal fusion were examined by scanning electron microscopy (SEM)...
2016: BioMed Research International
Audrey Thurm, Elaine Tierney, Cristan Farmer, Phebe Albert, Lisa Joseph, Susan Swedo, Simona Bianconi, Irena Bukelis, Courtney Wheeler, Geeta Sarphare, Diane Lanham, Christopher A Wassif, Forbes D Porter
BACKGROUND: Smith-Lemli-Opitz syndrome (SLOS) is an autosomal recessive inborn error of cholesterol metabolism syndrome with neurocognitive manifestations. SLOS is the result of mutations in the gene encoding the 7-dehydrocholesterol reductase, which results in the elevation of the cholesterol precursor 7-dehydrocholesterol (7-DHC). Previous reports indicate that intellectual disability, behavioral disturbances, and autism symptoms are frequently part of the SLOS behavioral phenotype...
2016: Journal of Neurodevelopmental Disorders
Mohammad Mh Abdullah, Audrey Cyr, Marie-Claude Lépine, Peter K Eck, Patrick Couture, Benoît Lamarche, Peter Jh Jones
BACKGROUND: Dairy intake has been associated with varying impacts on circulating cholesterol concentrations across nutritional epidemiology and intervention studies, with findings attributed mainly to differences in the nature of dairy products consumed or study designs. The contribution of the genomic architecture to such observations has yet to be revealed. OBJECTIVE: We assessed the impact of multiple common genetic variations in cholesterol-related genes on responses of serum cholesterol to the recommended amount of dairy product intake in Canada...
May 2016: Journal of Nutrition
William J Griffiths, Jonas Abdel-Khalik, Peter J Crick, Michael Ogundare, Cedric H Shackleton, Karin Tuschl, Mei Kwun Kwok, Brian W Bigger, Andrew A Morris, Akira Honda, Libin Xu, Ned A Porter, Ingemar Björkhem, Peter T Clayton, Yuqin Wang
Smith-Lemli-Opitz syndrome (SLOS) is a severe autosomal recessive disorder resulting from defects in the cholesterol synthesising enzyme 7-dehydrocholesterol reductase (Δ(7)-sterol reductase, DHCR7, EC leading to a build-up of the cholesterol precursor 7-dehydrocholesterol (7-DHC) in tissues and blood plasma. Although the underling enzyme deficiency associated with SLOS is clear there are likely to be multiple mechanisms responsible for SLOS pathology. In an effort to learn more of the aetiology of SLOS we have analysed plasma from SLOS patients to search for metabolites derived from 7-DHC which may be responsible for some of the pathology...
March 11, 2016: Journal of Steroid Biochemistry and Molecular Biology
Josi Herron, Rosalyn C Reese, Keri A Tallman, Rohini Narayanaswamy, Ned A Porter, Libin Xu
In this study, we aim to identify environmental molecules that can inhibit cholesterol biosynthesis, potentially leading to the same biochemical defects as observed in cholesterol biosynthesis disorders, which are often characterized by congenital malformations and developmental delay. Using the Distributed Structure-Searchable Toxicity (DSSTox) Database Network developed by EPA, we first carried out in silico screening of environmental molecules that display structures similar to AY9944, a known potent inhibitor of 3β-hydroxysterol-Δ(7)-reductase (DHCR7)-the last step of cholesterol biosynthesis...
June 2016: Toxicological Sciences: An Official Journal of the Society of Toxicology
Anika V Prabhu, Winnie Luu, Laura J Sharpe, Andrew J Brown
Cholesterol is detrimental to human health in excess but is also essential for normal embryogenesis. Hence, enzymes involved in its synthesis possess many layers of regulation to achieve balanced cholesterol levels. 7-Dehydrocholesterol reductase (DHCR7) is the terminal enzyme of cholesterol synthesis in the Kandutsch-Russell pathway, converting 7-dehydrocholesterol (7DHC) to cholesterol. In the absence of functional DHCR7, accumulation of 7DHC and a lack of cholesterol production leads to the devastating developmental disorder, Smith-Lemli-Opitz syndrome...
April 15, 2016: Journal of Biological Chemistry
Robert Blassberg, James I Macrae, James Briscoe, John Jacob
Smith-Lemli-Opitz syndrome (SLOS) is a common autosomal-recessive disorder that results from mutations in the gene encoding the cholesterol biosynthetic enzyme 7-dehydrocholesterol reductase (DHCR7). Impaired DHCR7 function is associated with a spectrum of congenital malformations, intellectual impairment, epileptiform activity and autism spectrum disorder. Biochemically, there is a deficit in cholesterol and an accumulation of its metabolic precursor 7-dehydrocholesterol (7DHC) in developing tissues. Morphological abnormalities in SLOS resemble those seen in congenital Sonic Hedgehog (SHH)-deficient conditions, leading to the proposal that the pathogenesis of SLOS is mediated by aberrant SHH signalling...
February 15, 2016: Human Molecular Genetics
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