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Wong BH, Silver DL. Mfsd2a: A Physiologically Important Lysolipid Transporter in the Brain and Eye. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1276:223-234. [PMID: 32705603 DOI: 10.1007/978-981-15-6082-8_14] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/03/2023]
Abstract
Lipids and essential fatty acids are required for normal brain development and continued photoreceptor membrane biogenesis for the maintenance of vision. The blood-brain barrier and blood-eye barriers prohibit the free diffusion of solutes into the brain and eye so that transporter-mediated uptake predominates at these barriers. The major facilitator superfamily of transporters constitutes one of the largest families of facilitative transporters across all domains of life. A unique family member, major facilitator superfamily domain containing 2a (Mfsd2a) is a lysophosphatidylcholine (LPC) transporter expressed at the blood-brain and blood-retinal barriers and demonstrated to be the major pathway for brain and eye accretion of docosahexaenoic acid (DHA) as an LPC. In addition to LPC-DHA, Mfsd2a can transport other LPCs containing mono- and polyunsaturated fatty acids. Mfsd2a deficiency in mouse and humans results in severe microcephaly, underscoring the importance of LPC transport in brain development. Beyond its role in brain development, LPC-DHA uptake in the brain and eye negatively regulates de novo lipogenesis. This review focuses on the current understanding of the physiological roles of Mfsd2a in the brain and eye and the proposed transport mechanism of Mfsd2a.
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Affiliation(s)
- Bernice H Wong
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - David L Silver
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore.
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Chan JP, Wong BH, Chin CF, Galam DLA, Foo JC, Wong LC, Ghosh S, Wenk MR, Cazenave-Gassiot A, Silver DL. The lysolipid transporter Mfsd2a regulates lipogenesis in the developing brain. PLoS Biol 2018; 16:e2006443. [PMID: 30074985 PMCID: PMC6093704 DOI: 10.1371/journal.pbio.2006443] [Citation(s) in RCA: 69] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 08/15/2018] [Accepted: 07/11/2018] [Indexed: 01/12/2023] Open
Abstract
Brain development requires a massive increase in brain lipogenesis and accretion of the essential omega-3 fatty acid docosahexaenoic acid (DHA). Brain acquisition of DHA is primarily mediated by the transporter Major Facilitator Superfamily Domain containing 2a (Mfsd2a) expressed in the endothelium of the blood-brain barrier (BBB) and other abundant cell types within the brain. Mfsd2a transports DHA and other polyunsaturated fatty acids (PUFAs) esterified to lysophosphatidylcholine (LPC-DHA). However, the function of Mfsd2a and DHA in brain development is incompletely understood. Here, we demonstrate, using vascular endothelial-specific and inducible vascular endothelial-specific deletion of Mfsd2a in mice, that Mfsd2a is uniquely required postnatally at the BBB for normal brain growth and DHA accretion, with DHA deficiency preceding the onset of microcephaly. In Mfsd2a-deficient mouse models, a lipidomic signature was identified that is indicative of increased de novo lipogenesis of PUFAs. Gene expression profiling analysis of these DHA-deficient brains indicated that sterol regulatory-element binding protein (Srebp)-1 and Srebp-2 pathways were highly elevated. Mechanistically, LPC-DHA treatment of primary neural stem cells down-regulated Srebp processing and activation in a Mfsd2a-dependent fashion, resulting in profound effects on phospholipid membrane saturation. In addition, Srebp regulated the expression of Mfsd2a. These data identify LPC-DHA transported by Mfsd2a as a physiological regulator of membrane phospholipid saturation acting in a feedback loop on Srebp activity during brain development. The brain is the most lipid-rich organ in the body. Brain development involves a tremendous increase in the synthesis and accretion of fatty acids. De novo synthesis of fatty acids is mediated by Srebp transcription factors, whereas acquisition of essential fatty acids via uptake of plasma-derived lysophosphatidylcholine containing the essential omega-3 fatty acid docosahexaenoic acid (LPC-DHA) is mediated by the transporter Mfsd2a in the cells that line the blood vessels in the brain. The function of Mfsd2a and DHA in brain development is incompletely understood. Our study determined that Mfsd2a is required at the blood-brain barrier for brain development and accretion of DHA after birth in mice. Moreover, we determined that a major function of DHA in the brain is to negatively regulate Srebp activation, resulting in profound effects on membrane phospholipid composition. These findings reveal that LPC-DHA transported by Mfsd2a plays a physiological role in both brain growth and in maintaining plasma membrane phospholipid composition during brain development.
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Affiliation(s)
- Jia Pei Chan
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Bernice H. Wong
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Cheen Fei Chin
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Dwight L. A. Galam
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Juat Chin Foo
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | - Loo Chin Wong
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
| | - Sujoy Ghosh
- Centre for Computational Biology, Duke-NUS Medical School, Singapore, Singapore
| | - Markus R. Wenk
- Department of Biochemistry, National University of Singapore, Singapore, Singapore
| | | | - David L. Silver
- Signature Research Program in Cardiovascular and Metabolic Disorders, Duke-NUS Medical School, Singapore, Singapore
- * E-mail:
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Nock TG, Chouinard-Watkins R, Plourde M. Carriers of an apolipoprotein E epsilon 4 allele are more vulnerable to a dietary deficiency in omega-3 fatty acids and cognitive decline. Biochim Biophys Acta Mol Cell Biol Lipids 2017; 1862:1068-1078. [PMID: 28733268 DOI: 10.1016/j.bbalip.2017.07.004] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2017] [Revised: 07/05/2017] [Accepted: 07/15/2017] [Indexed: 01/29/2023]
Abstract
Carriers of an epsilon 4 allele (E4) of apolipoprotein E (APOE) develop Alzheimer's disease (AD) earlier than carriers of other APOE alleles. The metabolism of plasma docosahexaenoic acid (DHA, 22:6n-3), an omega-3 fatty acid (n-3 FA), taken up by the brain and concentrated in neurons, is disrupted in E4 carriers, resulting in lower levels of brain DHA. Behavioural and cognitive impairments have been observed in animals with lower brain DHA levels, with emphasis on loss of spatial memory and increased anxiety. E4 mice provided a diet deficient in n-3 FA had a greater depletion of n-3 FA levels in organs and tissues than mice carrying other APOE alleles. However, providing n-3 FA can restore levels of brain DHA in E4 animals and in other models of n-3 FA deficiency. In E4 carriers, supplementation with DHA as early as possible might help to prevent the onset of AD and could halt the progression of, and reverse some of the neurological and behavioural consequences of their higher vulnerability to n-3 FA deficiency.
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Affiliation(s)
- Tanya Gwendolyn Nock
- Research Center on Aging, Centre Intégré Universitaire de Santé et Services Sociaux de l'Estrie-Centre Hospitalier Universitaire de Sherbrooke, Canada; Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Canada; Institute of Nutrition and Functional Foods, Quebec City, Canada
| | - Raphaël Chouinard-Watkins
- Research Center on Aging, Centre Intégré Universitaire de Santé et Services Sociaux de l'Estrie-Centre Hospitalier Universitaire de Sherbrooke, Canada; Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Canada; Institute of Nutrition and Functional Foods, Quebec City, Canada
| | - Mélanie Plourde
- Research Center on Aging, Centre Intégré Universitaire de Santé et Services Sociaux de l'Estrie-Centre Hospitalier Universitaire de Sherbrooke, Canada; Faculté de médecine et des sciences de la santé, Université de Sherbrooke, Sherbrooke, Canada; Institute of Nutrition and Functional Foods, Quebec City, Canada.
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Chevalier AC, Rosenberger TA. Increasing acetyl-CoA metabolism attenuates injury and alters spinal cord lipid content in mice subjected to experimental autoimmune encephalomyelitis. J Neurochem 2017; 141:721-737. [PMID: 28369944 DOI: 10.1111/jnc.14032] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2016] [Revised: 03/15/2017] [Accepted: 03/19/2017] [Indexed: 12/28/2022]
Abstract
Acetate supplementation increases brain acetyl-CoA metabolism, alters histone and non-histone protein acetylation, increases brain energy reserves, and is anti-inflammatory and neuroprotective in rat models of neuroinflammation and neuroborreliosis. To determine the impact acetate supplementation has on a mouse model of multiple sclerosis, we quantified the effect treatment had on injury progression, spinal cord lipid content, phospholipase levels, and myelin structure in mice subjected to experimental autoimmune encephalomyelitis (EAE). EAE was induced by inoculating mice with a myelin oligodendrocyte glycoprotein peptide fragment (MOG35-55 ), and acetate supplementation was maintained with 4 g/kg glyceryl triacetate by a daily oral gavage. Acetate supplementation prevented the onset of clinical signs in mice subject to EAE compared to control-treated mice. Furthermore, acetate supplementation prevented the loss of spinal cord ethanolamine and choline glycerophospholipid and phosphatidylserine in mice subjected to EAE compared to EAE animals treated with water. Treatment increased saturated and monounsaturated fatty acid levels in phosphatidylserine compared to controls suggesting that acetate was utilized to increase spinal cord fatty acid content. Also, acetate supplementation prevented the loss of spinal cord cholesterol in EAE animals but did not change cholesteryl esters. Treatment significantly increased GD3 and GD1a ganglioside levels in EAE mice when compared to EAE mice treated with water. Treatment returned levels of phosphorylated and non-phosphorylated cytosolic phospholipase A2 (cPLA2 ) levels back to baseline and based on FluoroMyelin™ histochemistry maintained myelin structural characteristics. Overall, these data suggest that acetate supplementation may modulate lipid metabolism in mice subjected to EAE.
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Affiliation(s)
- Amber C Chevalier
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, USA
| | - Thad A Rosenberger
- Department of Biomedical Sciences, University of North Dakota School of Medicine and Health Sciences, Grand Forks, North Dakota, USA
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Ge MM, Hu L, Li Z, Cheng G, Yan K, Kong Y, Wang H, Yang L, Zhou W. Novel compound heterozygous mutations in the PEX1 gene in two Chinese newborns with Zellweger syndrome based on whole exome sequencing. Clin Chim Acta 2017; 470:24-28. [PMID: 28432012 DOI: 10.1016/j.cca.2017.04.016] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/16/2017] [Revised: 04/16/2017] [Accepted: 04/18/2017] [Indexed: 11/18/2022]
Abstract
Peroxisome biogenesis disorders (PBDs) represent a spectrum of human genetic disorders that are characterized by damaged peroxisome assembly. In the newborn period, the characteristics of affected patients include dysmorphic facial features, neonatal hypotonia, seizures, ocular abnormalities, poor feeding, liver cysts with hepatic dysfunction and skeletal defects. These can be caused by a defect in at least 14 different PEX genes. In this study, whole-exome sequencing (WES) was performed on samples from two Chinese newborns with clinical features of Zellweger syndrome. WES identified two novel mutations (c.2416+1G>T and c.2489delT) in patient 1 and another two novel mutations (c.1483+1G>A and c.1727dupG) in patient 2 in the PEX1 gene. All four mutations have a serious influence on the protein function, which also highlights the power of WES, particularly in clinically challenging cases.
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Affiliation(s)
- Meng-Meng Ge
- Department of Neonates, Children's Hospital of Fudan University, Shanghai, China
| | - LiYuan Hu
- Department of Neonates, Children's Hospital of Fudan University, Shanghai, China
| | - ZhiHua Li
- Department of Neonates, Children's Hospital of Fudan University, Shanghai, China
| | - GuoQiang Cheng
- Department of Neonates, Children's Hospital of Fudan University, Shanghai, China
| | - Kai Yan
- Department of Neonates, Children's Hospital of Fudan University, Shanghai, China
| | - YanTing Kong
- Department of Neonates, Children's Hospital of Fudan University, Shanghai, China
| | - HuiJun Wang
- Birth Defect Laboratory, Children's Hospital of Fudan University, Shanghai, China
| | - Lin Yang
- Clinical Genetic Center, Children's Hospital of Fudan University, Shanghai, China
| | - WenHao Zhou
- Department of Neonates, Children's Hospital of Fudan University, Shanghai, China; Birth Defect Laboratory, Children's Hospital of Fudan University, Shanghai, China.
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C22-bronchial and T7-alveolar epithelial cell lines of the immortomouse are excellent murine cell culture model systems to study pulmonary peroxisome biology and metabolism. Histochem Cell Biol 2015; 145:287-304. [DOI: 10.1007/s00418-015-1385-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 10/29/2015] [Indexed: 10/22/2022]
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Astarita G, Piomelli D. Towards a whole-body systems [multi-organ] lipidomics in Alzheimer's disease. Prostaglandins Leukot Essent Fatty Acids 2011; 85:197-203. [PMID: 21543199 PMCID: PMC3161165 DOI: 10.1016/j.plefa.2011.04.021] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Preclinical and clinical evidence suggests that docosahexaenoic acid (DHA), an omega-3 fatty acid derived from diet or synthesized in the liver, decreases the risk of developing Alzheimer's disease (AD). DHA levels are reduced in the brain of subjects with AD, but it is still unclear whether human dementias are associated with dysregulations of DHA metabolism. A systems biological view of omega-3 fatty acid metabolism offered unexpected insights on the regulation of DHA homeostasis in AD [1]. Results of multi-organ lipidomic analyses were integrated with clinical and gene-expression data sets to develop testable hypotheses on the functional significance of lipid abnormalities observed and on their possible mechanistic bases. One surprising outcome of this integrative approach was the discovery that the liver of AD patients has a limited capacity to convert shorter chain omega-3 fatty acids into DHA due to a deficit in the peroxisomal d-bifunctional protein. This deficit may contribute to the decrease in brain DHA levels and contribute to cognitive impairment.
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Affiliation(s)
- Giuseppe Astarita
- Department of Pharmacology, 3101 Gillespie NRF, University of California, Irvine, CA 92697-4625, USA
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Abstract
An abundance of research has investigated causes and treatments for attention deficit hyperactivity disorder (ADHD). The research includes identification of suboptimal levels of nutrients and sensitivities to certain foods and food additives. This review gives an overview of this research and provides an up-to-date account of clinical trials that have been conducted with zinc, iron, magnesium, Pycnogenol, omega-3 fatty acids, and food sensitivities. A literature search was conducted using PubMed, ISI Web of Knowledge, and Google Scholar and included studies published before April 2008. Although further research is required, the current evidence supports indications of nutritional and dietary influences on behavior and learning in these children, with the strongest support to date reported for omega-3s and behavioral food reactions.
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Affiliation(s)
- Natalie Sinn
- Nutritional Physiology Research Centre, School of Health Sciences, University of South Australia, Adelaide, South Australia 5001, Australia.
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Hamilton JA, Hillard CJ, Spector AA, Watkins PA. Brain uptake and utilization of fatty acids, lipids and lipoproteins: application to neurological disorders. J Mol Neurosci 2008; 33:2-11. [PMID: 17901539 DOI: 10.1007/s12031-007-0060-1] [Citation(s) in RCA: 85] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/1999] [Revised: 11/30/1999] [Accepted: 11/30/1999] [Indexed: 10/23/2022]
Abstract
Transport, synthesis, and utilization of brain fatty acids and other lipids have been topics of investigation for more than a century, yet many fundamental aspects are unresolved and, indeed, subject to controversy. Understanding the mechanisms by which lipids cross the blood brain barrier and how they are utilized by neurons and glia is critical to understanding normal brain development and function, for the diagnosis and therapy of human diseases, and for the planning and delivery of optimal human nutrition throughout the world. Two particularly important fatty acids, both of which are abundant in neuronal membranes are: (a) the omega3 polyunsaturated fatty acid docosahexaenoic acid, deficiencies of which can impede brain development and compromise optimal brain function, and (b) the omega6 polyunsaturated fatty acid arachidonic acid, which yields essential, but potentially toxic, metabolic products. There is an exciting emerging evidence that modulating dietary intake of these fatty acids could have a beneficial effect on human neurological health. A workshop was held in October, 2004, in which investigators from diverse disciplines interacted to present new findings and to discuss issues relevant to lipid uptake, utilization, and metabolism in the brain. The objectives of this workshop were: (1) to assess the state-of-the-art of research in brain fatty acid/lipid uptake and utilization; (2) to discuss progress in understanding molecular mechanisms and the treatment of neurological diseases related to lipids and lipoproteins; (3) to identify areas in which current knowledge is insufficient; (4) to provide recommendations for future research; and (5) to stimulate the interest and involvement of additional neuroscientists, particularly young scientists, in these areas. The meeting was divided into four sessions: (1) mechanisms of lipid uptake and transport in the brain, (2) lipoproteins and polyunsaturated fatty acids, (3) eicosanoids in brain function, and (4) fatty acids and lipids in brain disorders. In this article, we will provide an overview of the topics discussed in these sessions.
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Tanaka K, Shimizu T, Ohtsuka Y, Yamashiro Y, Oshida K. Early dietary treatments with Lorenzo's oil and docosahexaenoic acid for neurological development in a case with Zellweger syndrome. Brain Dev 2007; 29:586-9. [PMID: 17418516 DOI: 10.1016/j.braindev.2007.02.005] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2006] [Revised: 02/09/2007] [Accepted: 02/13/2007] [Indexed: 11/25/2022]
Abstract
We treated a girl with Zellweger syndrome using a special infant formula supplemented with middle chain triglyceride (MCT) milk, docosahexaenoic acid (DHA), Lorenzo's oil, and Lunaria oil, which is rich in nervonic acid (C24:1). We examined the fatty acid contents of the plasma and red blood cell (RBC) membrane. Neurological development was evaluated using Denver developmental screening test and auditory brainstem response (ABR). Her delayed neurological development, liver dysfunction, and cholestasis were all improved 2 weeks after starting the dietary treatment. DHA level in RBC membranes was increased and very long chain fatty acid (VLCFA,C26:0) levels were decreased. Our findings suggest that the dietary treatment with combination of MCT milk, DHA, Lorenzo's oil, and Lunaria oil in the patients with Zellweger syndrome bring some benefits for neurological development.
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Affiliation(s)
- Kyoko Tanaka
- Department of Pediatrics, Juntendo University School of Medicine, 2-1-1 Hongo, 113-8421 Tokyo, Japan.
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Horrocks LA, Farooqui AA. Docosahexaenoic acid in the diet: its importance in maintenance and restoration of neural membrane function. Prostaglandins Leukot Essent Fatty Acids 2004; 70:361-72. [PMID: 15041028 DOI: 10.1016/j.plefa.2003.12.011] [Citation(s) in RCA: 200] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/18/2003] [Indexed: 11/30/2022]
Abstract
The central nervous system has the second highest concentration of lipids after adipose tissue. Long chain fatty acids, particularly arachidonic acid and docosahexaenoic acid, are integral components of neural membrane phospholipids. Alterations in neural membrane phospholipid components cannot only influence crucial intracellular and intercellular signaling but also alter many membrane physical properties such as fluidity, phase transition temperature, bilayer thickness, and lateral domains. A deficiency of docosahexaenoic acid markedly affects neurotransmission, membrane-bound enzyme and ion channel activities, gene expression, intensity of inflammation, and immunity and synaptic plasticity. Docosahexaenoic acid deficiency is associated with normal aging, Alzheimer disease, hyperactivity, schizophrenia, and peroxisomal disorders. Although the molecular mechanism of docosahexaenoic acid involvement in the disorders remains unknown, the supplementation of docosahexaenoic acid in the diet restores gene expression and modulates neurotransmission. Also, improvements are seen in signal transduction processes associated with behavioral deficits, learning activity, peroxisomal disorders, and psychotic changes in schizophrenia, depression, hyperactivity, stroke, and Alzheimer disease.
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Affiliation(s)
- Lloyd A Horrocks
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, OH 43210, USA.
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Abstract
Docosahexaenoic acid (DHA) and arachidonic acid (ARA) are important structural components of the central nervous system. These fatty acids are transferred across the placenta, are present in human milk, and are accumulated in the brain and retina during fetal and infant development. The high concentrations of DHA in the retina and of DHA and ARA in brain gray matter suggests that these fatty acids have important roles in retinal and neural function. Animal studies have shown that depletion of DHA from the retina and brain results in reduced visual function and learning deficits. The latter effects may be explained by changes in the membrane bilayer that alter membrane-associated receptors and signal transduction systems, ion channel activity, or direct effects on gene expression. DHA can be formed in the liver from alpha linolenic acid, but it is unclear if the rate of DHA synthesis in humans is sufficient to support optimal brain and retinal development. Although there is no evidence that the ability to form ARA from linoleic acid is limiting, supplementation with DHA reduces tissue ARA, possibly creating a conditional need for ARA in infants with a dietary intake of DHA. The amount of DHA in human milk varies widely and is positively correlated with visual and language development in breast-fed infants. Advances in understanding essential fatty acid requirements will benefit from intervention studies that use functionally relevant tests to probe the deficiency or adequacy of physiologically important pools of DHA and ARA in developing infants.
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Affiliation(s)
- Sheila M Innis
- Department of Pediatrics, University of British Columbia, Vancouver, British Columbia, Canada
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Sánchez-Font MF, Bosch-Comas A, Gonzàlez-Duarte R, Marfany G. Overexpression of FABP7 in Down syndrome fetal brains is associated with PKNOX1 gene-dosage imbalance. Nucleic Acids Res 2003; 31:2769-77. [PMID: 12771203 PMCID: PMC156729 DOI: 10.1093/nar/gkg396] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Abstract
Suppression subtractive hybridization performed on Down syndrome (DS) fetal brains revealed a differentially expressed gene, FABP7, mapped to 6q22-23. FABP7 overexpression in DS brains was verified by real-time PCR (1.63-fold). To elucidate the molecular basis of FABP7 overexpression and establish the relationship with chromosome 21 trisomy, the FABP7 promoter was cloned by genomic inverse PCR. Comparison to the mouse ortholog revealed conservation of reported regulatory elements, among them a Pbx/POU binding site, known to be the target of PBX heteromeric complexes. PBX partners include homeobox-containing proteins, such as PKNOX1 (PREP1), a transcription factor mapping at 21q22.3. We report here: (i) overexpression of PKNOX1 in DS fetal brains; (ii) in vitro specific binding of PKNOX1 to the Pbx/POU site of the FABP7 promoter; (iii) in vivo FABP7 promoter trans-activation in cultured neuroblastoma cells caused by PKNOX1 overexpression. To our knowledge this is the first report of a direct relation between dosage imbalance of a chromosome 21 gene and altered expression of a downstream gene mapping on another chromosome. Given the role of FABP7 in the establishment, development and maintenance of the CNS, we suggest that the overexpression of FABP7 could contribute to DS-associated neurological disorders.
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Affiliation(s)
- Ma Francisca Sánchez-Font
- Departament de Genètica, Facultat de Biologia, Universitat de Barcelona, Avda. Diagonal, 645, E-08028 Barcelona, Spain
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Farooqui AA, Ong WY, Horrocks LA. Plasmalogens, Docosahexaenoic Acid and Neurological Disorders. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2003; 544:335-54. [PMID: 14713251 DOI: 10.1007/978-1-4419-9072-3_45] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/20/2023]
Affiliation(s)
- Akhlaq A Farooqui
- Department of Molecular and Cellular Biochemistry, The Ohio State University, Columbus, Ohio 43210, USA.
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Styger R, Wiesmann UN, Honegger UE. Plasmalogen content and beta-adrenoceptor signalling in fibroblasts from patients with Zellweger syndrome. Effects of hexadecylglycerol. BIOCHIMICA ET BIOPHYSICA ACTA 2002; 1585:39-43. [PMID: 12457713 DOI: 10.1016/s1388-1981(02)00320-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
In Zellweger or cerebro-hepato-renal syndrome (CHRS), the assembly of peroxisomes is defective, resulting in deficient plasmalogen formation. Plasmalogens are part of the membrane lipid composition. In fibroblasts of CHRS patients, the plasmalogen fraction of phosphatidylethanolamine (PPE) was about half of that in control cells while total phospholipid (PL) content, individual PL and plasma membrane fluidity were normal. CHRS cell strains had higher beta-adrenoceptor numbers and isoproterenol-stimulated cAMP responses. Receptors were more efficiently coupled to adenylate cyclase than in control cells. Stimulations of cAMP with NaF or forskolin were the same as in control cells. Restoring synthesis of plasmalogens with hexadecylglycerol (HDG), a plasmalogen precursor, resulted in a proportionate increase in PPE of about 40% in both control and CHRS fibroblasts. Exposure to HDG reduced surface beta-adrenoceptor sites and cAMP-responses to isoproterenol in CHRS cells only, while post-receptor stimulations of cAMP were reduced in both cell types. Plasmalogen contents inversely correlated with isoproterenol-stimulated cAMP levels. The increased numbers of functional beta-adrenoceptors in CHRS fibroblasts may be the result of a higher expression and/or of a prolonged functional half-life of the receptor protein. In vivo, this may contribute to the clinical manifestations of the disease.
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Affiliation(s)
- Regula Styger
- Department of Pharmacology, University of Bern, Friedbuehlstr. 49, CH-3010, Bern, Switzerland
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Norris AW, Spector AA. Very long chain n-3 and n-6 polyunsaturated fatty acids bind strongly to liver fatty acid-binding protein. J Lipid Res 2002. [DOI: 10.1016/s0022-2275(20)31495-4] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Wainwright PE. Dietary essential fatty acids and brain function: a developmental perspective on mechanisms. Proc Nutr Soc 2002; 61:61-9. [PMID: 12002796 DOI: 10.1079/pns2001130] [Citation(s) in RCA: 252] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Brain development is a complex interactive process in which early disruptive events can have long-lasting effects on later functional adaptation. It is a process that is dependent on the timely orchestration of external and internal inputs through sophisticated intra- and intercellular signalling pathways. Long-chain polyunsaturated fatty acids (LCPUFA), specifically arachidonic acid and docosahexaenoic acid (DHA), accrue rapidly in the grey matter of the brain during development, and brain fatty acid (FA) composition reflects dietary availability. Membrane lipid components can influence signal transduction cascades in various ways, which in the case of LCPUFA include the important regulatory functions mediated by the eicosanoids, and extend to long-term regulation through effects on gene transcription. Our work indicates that FA imbalance as well as specific FA deficiencies can affect development adversely, including the ability to respond to environmental stimulation. For example, although the impaired water-maze performance of mice fed a saturated-fat diet improved in response to early environmental enrichment, the brains of these animals showed less complex patterns of dendritic branching. Dietary n-3 FA deficiency influences specific neurotransmitter systems, particularly the dopamine systems of the frontal cortex. We showed that dietary deficiency of n-3 FA impaired the performance of rats on delayed matching-to-place in the water maze, a task of the type associated with prefrontal dopamine function. We did not, however, find an association over a wider range of brain DHA levels and performance on this task. Some, but not all, studies of human infants suggest that dietary DHA may play a role in cognitive development as well as in some neurodevelopmental disorders; this possibility has important implications for population health.
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Affiliation(s)
- Patricia E Wainwright
- Department of Health Studies and Gerontology, University of Waterloo, Ontario, Canada.
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Ferdinandusse S, Denis S, Mooijer PA, Zhang Z, Reddy JK, Spector AA, Wanders RJ. Identification of the peroxisomal β-oxidation enzymes involved in the biosynthesis of docosahexaenoic acid. J Lipid Res 2001. [DOI: 10.1016/s0022-2275(20)31527-3] [Citation(s) in RCA: 41] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022] Open
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Watkins PA, Hamilton JA, Leaf A, Spector AA, Moore SA, Anderson RE, Moser HW, Noetzel MJ, Katz R. Brain uptake and utilization of fatty acids: applications to peroxisomal biogenesis diseases. J Mol Neurosci 2001; 16:87-92; discussion 151-7. [PMID: 11478388 DOI: 10.1385/jmn:16:2-3:87] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
The brain is rich in diverse fatty acids saturated, monounsaturated and polyunsaturated fatty acids with chain lengths ranging from less than 16 to more than 24 carbons that make up the complex lipids present in this organ. While some fatty acids are derived from endogenous synthesis, others must come from exogenous sources. The mechanism(s) by which fatty acids enter cells has been the subject of much debate. While some investigators argue for a protein-mediated process, others suggest that simple diffusion is sufficient. In the brain, uptake is further complicated by the presence of the blood-brain barrier. Brain fatty acid homeostasis is disturbed in many human disorders, as typified by the peroxisomal biogenesis diseases. A workshop designed to bring together researchers from varied backgrounds to discuss these issues in an open forum was held in March, 2000. In addition to assessing the current state of knowledge, areas requiring additional investigation were identified and recommendations for future research were made. A brief overview of the invited talks is presented here.
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Affiliation(s)
- P A Watkins
- Kennedy Krieger Institute, Baltimore, MD 21205, USA.
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Wei H, Kemp S, McGuinness MC, Moser AB, Smith KD. Pharmacological induction of peroxisomes in peroxisome biogenesis disorders. Ann Neurol 2001. [DOI: 10.1002/1531-8249(200003)47:3<286::aid-ana3>3.0.co;2-b] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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McGuinness MC, Wei H, Smith KD. Therapeutic developments in peroxisome biogenesis disorders. Expert Opin Investig Drugs 2000; 9:1985-92. [PMID: 11060787 DOI: 10.1517/13543784.9.9.1985] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Clinically, peroxisome biogenesis disorders (PBDs) are a group of lethal diseases with a continuum of severity of clinical symptoms ranging from the most severe form, Zellweger syndrome, to the milder forms, infantile Refsum disease and rhizomelic chondrodysplasia punctata. PBDs are characterised by a number of biochemical abnormalities including impaired degradation of peroxide, very long chain fatty acids, pipecolic acid, phytanic acid and xenobiotics and impaired synthesis of plasmalogens, bile acids, cholesterol and docosahexaenoic acid. Treatment of PBD patients as a group is problematic since a number of patients, especially those with Zellweger syndrome, have significant neocortical alterations in the brain at birth so that full recovery would be impossible even with postnatal therapy. To date, treatment of PBD patients has generally involved only supportive care and symptomatic therapy. However, the fact that some of the milder PBD patients live into the second decade has prompted research into possible treatments for these patients. A number of experimental therapies have been evaluated to determine whether or not correction of biochemical abnormalities through dietary supplementation and/or modification is of clinical benefit to PBD patients. Another approach has been pharmacological induction of peroxisomes in PBD patients to improve overall peroxisomal biochemical function. Well known rodent peroxisomal proliferators were found not to induce human peroxisomes. Recently, our laboratory demonstrated that sodium 4-phenylbutyrate induces peroxisome proliferation and improves biochemical function (very long chain fatty acid beta-oxidation rates and very long chain fatty acid and plasmalogens levels) in fibroblast cell lines from patients with milder PBD phenotypes. Dietary supplementation and/or modification and pharmacological induction of peroxisomes as treatment strategies for PBD patients will be the subject of this review.
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Affiliation(s)
- M C McGuinness
- Kennedy Krieger Institute, Room 400A, 707 North Broadway, Baltimore, MD 21205, USA.
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Affiliation(s)
- R Uauy
- Institute of Nutrition and Food Technology (INTA), University of Chile, Santiago.
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SanGiovanni JP, Parra-Cabrera S, Colditz GA, Berkey CS, Dwyer JT. Meta-analysis of dietary essential fatty acids and long-chain polyunsaturated fatty acids as they relate to visual resolution acuity in healthy preterm infants. Pediatrics 2000; 105:1292-8. [PMID: 10835071 DOI: 10.1542/peds.105.6.1292] [Citation(s) in RCA: 194] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To derive combined estimates of visual resolution acuity differences between healthy preterm infants consuming different compositions and ratios of essential fatty acids (EFAs) and docosahexaenoic acid (DHA), an omega-3 (n-3) long-chain polyunsaturated fatty acid (LCPUFA). DATA SOURCES Electronic biomedical reference database (Medline and Health Star from 1965 to July 1999) searches with index terms omega-3, n-3, infant, vision, acuity, and human. Current review article, monograph, and book chapter bibliography/reference section hand searches. STUDY SELECTION A total of 5 original articles and 4 review chapters were reviewed for details on study design, conduct, and outcome. Four prospective trials of EFA/LCPUFA supplementation were included in these analyses. For behaviorally based outcomes, there were 2 randomized comparisons each at </=1, 2, 6, 9, and 12 months of corrected age and 4 randomized comparisons at 4 months of corrected age. For electrophysiologically based outcomes (visual-evoked potential), there were 2 randomized comparisons each at </=1 and approximately 4 months of corrected age. DATA EXTRACTION Dietary composition and EFA/LCPUFA balance, study design, and analytic characteristics (duration of feeding, source of EFAs/LCPUFAs, number of subjects in study population, number of subjects analyzed, and basis for estimating age), and experiment-based characteristics (location, number or sites, design, vision tests employed, testing protocol, and ophthalmic examination) were recorded independently by 2 researchers with a standardized protocol. DATA SYNTHESIS The relative difference in visual resolution acuity between groups of infants who received a source of dietary EFAs/LCPUFAs and groups who did not was computed and then analyzed with the DerSimonian and Laird random-effects method. RESULTS Analysis of the randomized comparisons (DHA-supplemented formula vs DHA-free formula) showed significant differences in visual resolution acuity at 2 and 4 months of age. Combined estimates of behaviorally based visual resolution acuity differences at these ages were.47 +/-.14 octaves and.28 +/-.08 octaves, respectively. A 1-octave difference is a reduction in the width of the stimulus elements by 50%. CONCLUSION These results support efficacy of n-3 LCPUFA intake in early visual system development, although supplementation safety issues still must be addressed through larger randomized trials. Whether n-3 intake confers lasting advantage in visually based process development across the life-span is still to be determined.
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Affiliation(s)
- J P SanGiovanni
- Department of Maternal and Child Health, Harvard School of Public Health, Boston, Massachusetts, USA.
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SanGiovanni JP, Berkey CS, Dwyer JT, Colditz GA. Dietary essential fatty acids, long-chain polyunsaturated fatty acids, and visual resolution acuity in healthy fullterm infants: a systematic review. Early Hum Dev 2000; 57:165-88. [PMID: 10742608 DOI: 10.1016/s0378-3782(00)00050-5] [Citation(s) in RCA: 163] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
BACKGROUND Biologically active neural tissue is rich in docosahexaenoic acid (DHA), an omega-3 long-chain polyunsaturated fatty acid (LCPUFA). We conducted a systematic review to examine the nature of discordant results from studies designed to test the hypothesis that dietary DHA leads to better performance on visually-based tasks in healthy, fullterm infants. We also conducted a meta-analysis to derive combined estimates of behavioral- and electrophysiologic-based visual resolution acuity differences and sample sizes that would be useful in planning future research. STUDY DESIGN AND METHODS Twelve empirical studies on LCPUFA intake during infancy and visual resolution acuity were identified through bibliographic searches, examination of monograph and review article reference lists, and written requests to researchers in the field. Works were reviewed for quality and completeness of information. Study design and conduct information was extracted with a standardized protocol. Acuity differences between groups consuming a source of DHA and groups consuming DHA-free diets were calculated as a common outcome from individual studies; this difference score was evaluated against a null value of zero and then used, with the method of DerSimonian and Laird (Meta-analysis in clinical trials. Control Clin Trials 1986;7:177-188), to derive combined estimates of visual resolution acuity differences within seven age categories. RESULTS OF RANDOMIZED COMPARISONS: The combined visual resolution acuity difference measured with behaviorally based methods between DHA-supplemented formula fed groups and DHA-free formula fed groups is 0.32+/-0.09 octaves (combined difference+/-S.E.M., P=0.0003) at 2 months of age. The direction of this value indicates higher acuity in DHA-fed groups. RESULTS OF NON-RANDOMIZED STUDY DESIGNS: The combined visual resolution acuity difference measured with behaviorally based methods between human milk fed groups and DHA-free formula fed groups is 0.49+/-0.09 octaves (P< or =0.000001) at 2 months of age and 0.18+/-0.08 octaves (P=0.04) at 4 months of age. Acuity differences for electrophysiologic-based measures are also greater than zero at 4 months (0.37+/-0.16 octaves, P=0.02). CONCLUSION Some aspect of dietary n-3 intake is associated with performance on visual resolution acuity tasks at 2, and possibly, 4 months of age in healthy fullterm infants. Whether n-3 intake confers lasting advantage in the development of visually based processes is still in question.
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Affiliation(s)
- J P SanGiovanni
- Department of Maternal and Child Health, Harvard School of Public Health, Boston, MA 02114-0500, USA.
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Infante JP, Huszagh VA. Secondary carnitine deficiency and impaired docosahexaenoic (22:6n-3) acid synthesis: a common denominator in the pathophysiology of diseases of oxidative phosphorylation and beta-oxidation. FEBS Lett 2000; 468:1-5. [PMID: 10683429 DOI: 10.1016/s0014-5793(00)01083-8] [Citation(s) in RCA: 58] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
A critical analysis of the literature of mitochondrial disorders reveals that genetic diseases of oxidative phosphorylation are often associated with impaired beta-oxidation, and vice versa, and preferentially affect brain, retina, heart and skeletal muscle, tissues which depend on docosahexaenoic (22:6n-3)-containing phospholipids for functionality. Evidence suggests that an increased NADH/NAD(+) ratio generated by reduced flux through the respiratory chain inhibits beta-oxidation, producing secondary carnitine deficiency while increasing reactive oxygen species and depleting alpha-tocopherol (alpha-TOC). These events result in impairment of the recently elucidated mitochondrial pathway for synthesis of 22:6n-3-containing phospholipids, since carnitine and alpha-TOC are involved in their biosynthesis. Therapeutic supplementation with 22:6n-3 and alpha-TOC is suggested.
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Affiliation(s)
- J P Infante
- Institute for Theoretical Biochemistry, Ithaca, NY, USA.
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Janssen A, Baes M, Gressens P, Mannaerts GP, Declercq P, Van Veldhoven PP. Docosahexaenoic acid deficit is not a major pathogenic factor in peroxisome-deficient mice. J Transl Med 2000; 80:31-5. [PMID: 10653000 DOI: 10.1038/labinvest.3780005] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Abstract
Docosahexaenoic acid (DHA), a major component of membrane phospholipids in brain and retina, is profoundly reduced in patients with peroxisome biogenesis disorders (Zellweger syndrome). Supplementing newborn patients with DHA resulted in improved muscular tone and visual functions. The purpose of this study was to investigate (a) whether DHA levels were also reduced in newborn PEX5 knockout mice, the mouse model of Zellweger syndrome that we recently generated; (b) whether these levels could be normalized by supplying DHA; and (c) whether this results in longer survival. The DHA concentration in brain of newborn PEX5-/- mice was reduced by 40% as compared with levels in normal littermates; in liver, no differences were noticed. The daily administration of 10 mg of DHA-ethyl ester (EE) to pregnant heterozygous mothers during the last 8 days of gestation resulted in a normalization of brain DHA levels in Zellweger pups. However, no clinical improvement was observed in these pups, and the neuronal migration defect was unaltered. These data suggest that the accretion of DHA in the brain at the end of embryonic development is not only supported by the maternal supply but also depends on synthesis in the fetal brain. Furthermore, the DHA deficit does not seem to be a major pathogenic factor in the newborn Zellweger mice.
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Affiliation(s)
- A Janssen
- Laboratory of Clinical Chemistry, Faculty of Pharmaceutical Sciences, K.U. Leuven, Belgium.
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Martínez M, Vázquez E, García-Silva MT, Manzanares J, Bertran JM, Castelló F, Mougan I. Therapeutic effects of docosahexaenoic acid ethyl ester in patients with generalized peroxisomal disorders. Am J Clin Nutr 2000; 71:376S-85S. [PMID: 10618001 DOI: 10.1093/ajcn/71.1.376s] [Citation(s) in RCA: 95] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Generalized peroxisomal disorders are severe congenital diseases that involve the central nervous system, leading to severe psychomotor retardation, retinopathy, liver disease, and early death. In these disorders, peroxisomes are not normally formed and their enzymes are deficient. Characteristically, plasmalogen synthesis and beta-oxidation of very-long-chain fatty acids (VLCFAs) are affected. We found that patients with generalized peroxisomal disorders have a profound brain deficiency of docosahexaenoic acid (DHA; 22:6n-3) and low DHA concentrations in all tissues and the blood. Given the fundamental role of DHA in neuronal and retinal membranes, a DHA deficiency of this magnitude might be pathogenic. Thus, we studied the possible therapeutic effect of normalizing DHA concentrations in patients with peroxisomal disorders. We chose the DHA ethyl ester (DHA-EE) because of its high degree of purity at daily oral doses of 100-500 mg. This article summarizes the results of treatment of 13 patients with DHA-EE, with some follow-up evidence of clinical improvement. Supplementation with DHA-EE normalized blood DHA values within a few weeks. Plasmalogen concentrations increased in erythrocytes in most patients and after DHA concentrations were normalized, amounts of VLCFAs decreased in plasma. Liver enzymes returned almost to normal in most cases. From a clinical viewpoint, most patients showed improvement in vision, liver function, muscle tone, and social contact. In 3 patients, normalization of brain myelin was detected by magnetic resonance imaging. In 3 others, myelination improved. In a seventh patient, myelination is progressing at a normal rate. These results suggest a fundamental role of DHA in the pathogenesis of Zellweger syndrome. DHA therapy is thus strongly recommended, not only to alleviate symptoms in patients with life-threatening diseases, but also to clarify remaining questions regarding the role of DHA in health and disease.
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Affiliation(s)
- M Martínez
- Hospital Materno-Infantil Vall d'Hebron, Barcelona, Spain, and the Hospital 12 de Octubre, Madrid, Spain.
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Zaouali-Ajina M, Gharib A, Durand G, Gazzah N, Claustrat B, Gharib C, Sarda N. Dietary docosahexaenoic acid-enriched phospholipids normalize urinary melatonin excretion in adult (n-3) polyunsaturated fatty acid-deficient rats. J Nutr 1999; 129:2074-80. [PMID: 10539787 DOI: 10.1093/jn/129.11.2074] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Melatonin (MEL) plays an essential role in physiologic functions associated with darkness. We examined the effects of docosahexaenoic acid (DHA)-enriched phospholipids from pig brains (BPL) or hen eggs (EPL), as sources of DHA, on lipid FA composition of pineal membranes and daytime and nighttime concentrations of 6-sulfatoxymelatonin (aMT6) in adult male control and (n-3)-deficient rats fed BPL and EPL diets for 5 wk. In two experiments, at 3 wk of age, rats were divided into subgroups and fed semipurified diets containing either peanut oil [(n-3)-deficient group] or peanut plus rapeseed oil (control group) and two dietary formulas containing either 3.5 g/100 g diet of BPL (Experiment 1) or 5.0 g/100 g diet of EPL (Experiment 2). BPL and EPL diets provided approximately 200 mg of DHA/100 g diet. During the daytime, aMT6 concentrations were not significantly different among groups. Conversely, the (n-3)-deficient rats had significantly lower nighttime aMT6 concentrations than the control rats. BPL and EPL did not affect urinary nighttime aMT6 concentration in the control group, whereas (n-3)-deficient + BPL or EPL groups exhibited significantly higher nighttime aMT6 concentrations than the (n-3)-deficient group (76 and 110%, respectively). The level of DHA was significantly higher in the pineal glands of control rats than in (n-3)-deficient rats. In rats fed EPL and BPL, the level of DHA reached a plateau, between 10 and 11 mg/100 mg total fatty acids in control + BPL or EPL and (n-3)-deficient + BPL or EPL groups. These findings suggest that new DHA-enriched formulas may be used as an efficient alternative source of (n-3) polyunsaturated fatty acids to normalize MEL secretion.
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Affiliation(s)
- M Zaouali-Ajina
- Laboratoire de Physiologie de l'Environnement, Faculté de Médecine Lyon Grange-Blanche, 69373 Lyon Cedex 08, France
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Kim HY, Edsall L, Garcia M, Zhang H. The release of polyunsaturated fatty acids and their lipoxygenation in the brain. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1999; 447:75-85. [PMID: 10086184 DOI: 10.1007/978-1-4615-4861-4_7] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/01/2023]
Abstract
Stimulation of neuronal tissues with neurotransmitters results in the release of the polyunsaturated fatty acids 20:4n6 and 22:6n3. Astroglial cells hydrolyze 20:4n6 and 22:6n3 equally well under both stimulated and basal conditions. Despite the high abundance of 22:6n3 in neuronal membranes, 20:4n6 is preferentially hydrolyzed from neuronal cells. These results suggest that 22:6n3 may be of more physiological importance in neuronal membranes as a membrane component rather than as a released free fatty acid while in astroglia, release of 22:6n3 may also be a significant step involved in receptor-stimulated signaling processes. Oxygenation of these polyunsaturated fatty acids occurs in the brain. However, in contrast to the prevailing belief, lipid peroxidation rather than lipoxygenation is primarily responsible for their formation. In rodent brains, any significant lipoxygenation appears to occur only in the pineal. The production of hydroxylated polyunsaturated fatty acids in pineal may play a role in the pineal function especially in relation to melatonin synthesis.
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Affiliation(s)
- H Y Kim
- National Institute on Alcohol Abuse and Alcoholism, National Institutes of Health, Rockville, Maryland 20852, USA
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Plasmalogen status influences docosahexaenoic acid levels in a macrophage cell line: insights using ether lipid-deficient variants. J Lipid Res 1999. [DOI: 10.1016/s0022-2275(20)32454-8] [Citation(s) in RCA: 43] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
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Josephson R, Müller T, Pickel J, Okabe S, Reynolds K, Turner PA, Zimmer A, McKay RD. POU transcription factors control expression of CNS stem cell-specific genes. Development 1998; 125:3087-100. [PMID: 9671582 DOI: 10.1242/dev.125.16.3087] [Citation(s) in RCA: 119] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Multipotential stem cells throughout the developing central nervous system have common properties. Among these is expression of the intermediate filament protein nestin and the brain fatty acid binding protein (B-FABP). To determine if common mechanisms control transcription in CNS stem cells, the regulatory elements of these two genes were mapped in transgenic mice. A 257 basepair enhancer of the rat nestin gene is sufficient for expression throughout the embryonic neuroepithelium. This enhancer contains two sites bound by the class III POU proteins Brn-1, Brn-2, Brn-4, and Tst-1. Only one of the two POU sites is required for CNS expression. An adjacent hormone response element is necessary for expression in the dorsal midbrain and forebrain. The regulatory sites of the B-FABP gene are strikingly similar to those of the nestin gene. A hybrid POU/Pbx binding site is recognized in vitro by Pbx-1, Brn-1 and Brn-2. This site is essential for expression in most of the CNS. In addition, a hormone response element is necessary for forebrain expression. Both the nestin and B-FABP genes therefore depend on POU binding sites for general CNS expression, with hormone response elements additionally required for activity in the anterior CNS. These data indicate that regulation by POU proteins and hormone receptors is a general mechanism for CNS stem cell-specific transcription.
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Affiliation(s)
- R Josephson
- Laboratory of Molecular Biology, National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892-4157, USA
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Petroni A, Bertagnolio B, La Spada P, Blasevich M, Papini N, Govoni S, Rimoldi M, Galli C. The beta-oxidation of arachidonic acid and the synthesis of docosahexaenoic acid are selectively and consistently altered in skin fibroblasts from three Zellweger patients versus X-adrenoleukodystrophy, Alzheimer and control subjects. Neurosci Lett 1998; 250:145-8. [PMID: 9708853 DOI: 10.1016/s0304-3940(98)00467-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The beta-oxidation of [3H] arachidonic acid (AA; 20:4 n-6) and the conversion of [1-14C]eicosapentaenoic acid (EPA, 20:5 n-3) to docosahexaenoic acid (DHA, 22:6 n-3) have been studied in skin fibroblasts from patients with inherited peroxisomal diseases, such as Zellweger (ZW) and X-linked adrenoleukodystrophy (X-ALD), from patients with Alzheimer's disease (AD), a non-inherited neuropathology, and from controls. EPA is not converted to DHA, while there is enhanced formation of the intermediate product 22:5 n-3 in ZW, when compared to X-ALD, AD and controls. We also confirmed that AA is not beta-oxidized to 4,7,10-hexadecatrienoic acid (16:3), a metabolite produced by peroxisomes, while being more effectively converted to the elongation product 22:4, in ZW, in comparison to X-ALD, AD and controls. The data demonstrate a defect in DHA synthesis and in AA beta-oxidation, and the occurrence of associated adaptative modifications in the metabolism of these long chain PUFA, in three Italian ZW patients.
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Affiliation(s)
- A Petroni
- Institute of Pharmacological Sciences, University of Milan, Italy.
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Infante JP, Huszagh VA. Analysis of the putative role of 24-carbon polyunsaturated fatty acids in the biosynthesis of docosapentaenoic (22:5n-6) and docosahexaenoic (22:6n-3) acids. FEBS Lett 1998; 431:1-6. [PMID: 9684854 DOI: 10.1016/s0014-5793(98)00720-0] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
The recent literature on the putative involvement of a single cycle of peroxisomal beta-oxidation of 24:5n-6 and 24:6n-3 polyunsaturated fatty acids in the biosynthesis of the respective docosapentaenoic (22:5n-6) and docosahexaenoic (22:6n-3) fatty acids is critically reviewed. Present evidence suggests that in vitro data in support of the above proposition is an artifact of a low 2,4-dienoyl-CoA reductase activity due to depletion of NADPH resulting from incubation conditions. Kinetic studies with radiolabeled precursors in cell cultures have shown lower initial rates of labeling of 24:6n-3 than that of 22:6n-3, indicating that 24:6n-3 is an elongation product of 22:6n-3 rather than its precursor. Analysis of other literature data supports the proposal that 22:5n-6 and 22:6n-3 are synthesized in mitochondria via channeled carnitine-dependent pathways involving separate n-6- and n-3-specific desaturases. It is proposed that impaired peroxisomal function in some peroxisomal disorders is a secondary consequence of defective mitochondrial synthesis of 22:6n-3; moreover, some disorders of peroxisomal beta-oxidation show normal or increased 22:5n-6 concentrations, indicating that 22:5n-6 is synthesized by independent desaturases without peroxisomal involvement.
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Affiliation(s)
- J P Infante
- Institute for Theoretical Biochemistry and Molecular Biology, Ithaca, NY 14852-4512, USA
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Zhang H, Hamilton JH, Salem N, Kim HY. N–3 fatty acid deficiency in the rat pineal gland: effects on phospholipid molecular species composition and endogenous levels of melatonin and lipoxygenase products. J Lipid Res 1998. [DOI: 10.1016/s0022-2275(20)32520-7] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022] Open
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Poley JR, Nowicki MJ. Other hereditary diseases and the liver. BAILLIERE'S CLINICAL GASTROENTEROLOGY 1998; 12:369-407. [PMID: 9890078 DOI: 10.1016/s0950-3528(98)90140-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
In this chapter, an abbreviated account is presented on the subject of hereditary diseases and the liver. However, it is incomplete because Alagille syndrome, storage disorders, alpha-1-antitrypsin deficiency and Wilson disease are not included as they appear in other chapters of this volume. Biliary atresia is omitted because all available evidence does not support any significant genetic association. Molecular biological techniques have enabled linkage of several liver cholestatic disorders to chromosomal loci, and further characterization of the canalicular bile salt transporter (cBST) will advance our understanding of pathogenetic mechanisms involved in benign and progressive cholestatic syndromes. Disorders that have been treated as separate entities may have common 'roots', exemplified by the concept of the ductal plate malformation in fibropolycystic disease. Whereas the majority of disorders referred to in this chapter present early in life, there are several that are associated with liver failure in the neonatal period, which makes early recognition particularly important. Liver transplantation offers a cure for many hereditary disorders affecting the liver but it is not applicable to all.
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Affiliation(s)
- J R Poley
- Department of Paediatrics, Children's Hospital of The King's Daughters, Norfolk, Virginia, USA
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Infante JP, Huszagh VA. On the molecular etiology of decreased arachidonic (20:4n-6), docosapentaenoic (22:5n-6) and docosahexaenoic (22:6n-3) acids in Zellweger syndrome and other peroxisomal disorders. Mol Cell Biochem 1997; 168:101-15. [PMID: 9062899 DOI: 10.1023/a:1006895209833] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023]
Abstract
Alterations in the metabolism of arachidonic (20:4n-6), docosapentaenoic (22:5n-6), and docosahexaenoic (22:6n-3) acids and other polyunsaturated fatty acids in Zellweger syndrome and other peroxisomal disorders are reviewed. Previous proposals that peroxisomes are necessary for the synthesis of 22:6n-3 and 22:5n-6 are critically examined. The data suggest that 22:6n-3 is biosynthesized in mitochondria via a channelled carnitine-dependent pathway involving an n-3-specific delta-4 desaturase, while 20:4n-6, 20:5n-3 and 22:5n-6 are synthesized by both mitochondrial and microsomal systems; these pathways are postulated to be interregulated as compensatory-redundant systems. Present evidence suggests that 22:6n-3-containing phospholipids may be required for the biochemical events involved in successful neuronal migration and developmental morphogenesis, and as structural cofactors for the functional assembly and integration of a variety of membrane enzymes, receptors, and other proteins in peroxisomes and other subcellular organelles. A defect in the mitochondrial desaturation pathway is proposed to be a primary etiologic factor in the clinicopathology of Zellweger syndrome and other related disorders. Several implications of this proposal are examined relating to effects of pharmacological agents which appear to inhibit steps in this pathway, such as some hypolipidemics (fibrates), neuroleptics (phenothiazines and phenytoin) and prenatal alcohol exposure.
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Affiliation(s)
- J P Infante
- Institute for Theoretical Biochemistry and Molecular Biology, Ithaca, New York 14852-4512, USA
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