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Abstract
The condition originally called Hallervorden-Spatz syndrome is a collection of related disorders involving abnormal iron accumulation in the basal ganglia, usually manifesting with a movement disorder. To date, mutations in the following genes have been associated with neurodegeneration with brain iron accumulation (NBIA) phenotypes: PANK2, PLA2G6, FA2H, ATP13A2, C2orf37, CP, and FTL. This collection, now classified under the umbrella term NBIA, continues to evolve as new genes and associated phenotypes are recognized. As this body of information continues to grow, better approaches to diagnosis and treatment have become available. Continued investigations of the underlying pathogenesis of disease, with a focus on lipid, iron, and energy metabolism, will lead to the identification of new therapeutic targets.
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Affiliation(s)
- Allison Gregory
- Department of Molecular & Medical Genetics, Oregon Health & Science University, 3181 S.W. Sam Jackson Park Road, Mailcode L103, Portland, OR 97239-3098, USA.
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152
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Yuki D, Sugiura Y, Zaima N, Akatsu H, Hashizume Y, Yamamoto T, Fujiwara M, Sugiyama K, Setou M. Hydroxylated and non-hydroxylated sulfatide are distinctly distributed in the human cerebral cortex. Neuroscience 2011; 193:44-53. [PMID: 21802498 DOI: 10.1016/j.neuroscience.2011.07.045] [Citation(s) in RCA: 46] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2011] [Revised: 07/18/2011] [Accepted: 07/19/2011] [Indexed: 10/17/2022]
Abstract
Sulfatide (ST) is a sphingolipid with an important role in the central nervous system as a major component of the myelin sheath. ST contains a structurally variable ceramide moiety, with a fatty acid substituent of varying carbon-chain length and double-bond number. Hydroxylation at the α-2 carbon position of the fatty acid is found in half the population of ST molecules. Recent genetic studies of fatty acid 2-hydroxylase (FA2H) indicate that these hydroxylated sphingolipids influence myelin sheath stability. However, their distribution is unknown. Matrix-assisted laser desorption/ionization imaging mass spectrometry (MALDI-IMS) enables the analysis of distinct distributions of individual ST molecular species in tissue section. We examined human cerebral cortex tissue sections with MALDI-IMS, identifying and characterizing the distributions of 14 ST species. The distribution analysis reveals that the composition ratios of non-hydroxylated/hydroxylated STs are clearly reversed at the border between white and gray matter; the hydroxylated group is the dominant ST species in the gray matter. These results suggest that hydroxylated STs are highly expressed in oligodendrocytes in gray matter and might form stable myelin sheaths. As a clinical application, we analyzed a brain with Alzheimer's disease (AD) as a representative neurodegenerative disease. Although previous studies of AD pathology have reported that the amount of total ST is decreased in the cerebral cortex, as far as the compositional distributions of STs are concerned, AD brains were similar to those in control brains. In conclusion, we suggest that MALDI-IMS is a useful tool for analysis of the distributions of various STs and this application might provide novel insight in the clinical study of demyelinating diseases.
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Affiliation(s)
- D Yuki
- Research and Development Headquarters, Lion Corporation, 7-2-1 Hirai, Edogawa-ku, Tokyo 132-0035, Japan
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153
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Schipper HM. Neurodegeneration with brain iron accumulation - clinical syndromes and neuroimaging. Biochim Biophys Acta Mol Basis Dis 2011; 1822:350-60. [PMID: 21782937 DOI: 10.1016/j.bbadis.2011.06.016] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2011] [Revised: 06/20/2011] [Accepted: 06/21/2011] [Indexed: 12/14/2022]
Abstract
Iron participates in a wide array of cellular functions and is essential for normal neural development and physiology. However, if inappropriately managed, the transition metal is capable of generating neurotoxic reactive oxygen species. A number of hereditary conditions perturb body iron homeostasis and some, collectively referred to as neurodegeneration with brain iron accumulation (NBIA), promote pathological deposition of the metal predominantly or exclusively within the central nervous system (CNS). In this article, we discuss seven NBIA disorders with emphasis on the clinical syndromes and neuroimaging. The latter primarily entails magnetic resonance scanning using iron-sensitive sequences. The conditions considered are Friedreich ataxia (FA), pantothenate kinase 2-associated neurodegeneration (PKAN), PLA2G6-associated neurodegeneration (PLAN), FA2H-associated neurodegeneration (FAHN), Kufor-Rakeb disease (KRD), aceruloplasminemia, and neuroferritinopathy. An approach to differential diagnosis and the status of iron chelation therapy for several of these entities are presented. This article is part of a Special Issue entitled: Imaging Brain Aging and Neurodegenerative disease.
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Affiliation(s)
- Hyman M Schipper
- Centre for Neurotranslational Research, Lady Davis Institute, Jewish General Hospital, Montreal, Quebec, Canada H3T 1E2.
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154
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Abstract
Intensive research over the past 2 decades has implicated ceramide in the regulation of several cell responses. However, emerging evidence points to dramatic complexities in ceramide metabolism and structure that defy the prevailing unifying hypothesis on ceramide function that is based on the understanding of ceramide as a single entity. Here, we develop the concept that "ceramide" constitutes a family of closely related molecules, subject to metabolism by >28 enzymes and with >200 structurally distinct mammalian ceramides distinguished by specific structural modifications. These ceramides are synthesized in a combinatorial fashion with distinct enzymes responsible for the specific modifications. These multiple pathways of ceramide generation led to the hypothesis that individual ceramide molecular species are regulated by specific biochemical pathways in distinct subcellular compartments and execute distinct functions. In this minireview, we describe the "many ceramides" paradigm, along with the rationale, supporting evidence, and implications for our understanding of bioactive sphingolipids and approaches for unraveling these pathways.
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Affiliation(s)
- Yusuf A Hannun
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SouthCarolina 29425, USA.
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155
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Maier H, Meixner M, Hartmann D, Sandhoff R, Wang-Eckhardt L, Zöller I, Gieselmann V, Eckhardt M. Normal fur development and sebum production depends on fatty acid 2-hydroxylase expression in sebaceous glands. J Biol Chem 2011; 286:25922-34. [PMID: 21628453 DOI: 10.1074/jbc.m111.231977] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
2-Hydroxylated fatty acid (HFA)-containing sphingolipids are abundant in mammalian skin and are believed to play a role in the formation of the epidermal barrier. Fatty acid 2-hydroxylase (FA2H), required for the synthesis of 2-hydroxylated sphingolipids in various organs, is highly expressed in skin, and previous in vitro studies demonstrated its role in the synthesis of HFA sphingolipids in human keratinocytes. Unexpectedly, however, mice deficient in FA2H did not show significant changes in their epidermal HFA sphingolipids. Expression of FA2H in murine skin was restricted to the sebaceous glands, where it was required for synthesis of 2-hydroxylated glucosylceramide and a fraction of type II wax diesters. Absence of FA2H resulted in hyperproliferation of sebocytes and enlarged sebaceous glands during hair follicle morphogenesis and anagen (active growth phase) in adult mice. This was accompanied by a significant up-regulation of the epidermal growth factor receptor ligand epigen in sebocytes. Loss of FA2H significantly altered the composition and physicochemical properties of sebum, which often blocked the hair canal, apparently causing a delay in the hair fiber exit. Furthermore, mice lacking FA2H displayed a cycling alopecia with hair loss in telogen. These results underline the importance of the sebaceous glands and suggest a role of specific sebaceous gland or sebum lipids, synthesized by FA2H, in the hair follicle homeostasis.
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Affiliation(s)
- Helena Maier
- Institute of Biochemistry and Molecular Biology, Germany
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156
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Dan P, Edvardson S, Bielawski J, Hama H, Saada A. 2-Hydroxylated sphingomyelin profiles in cells from patients with mutated fatty acid 2-hydroxylase. Lipids Health Dis 2011; 10:84. [PMID: 21599921 PMCID: PMC3107802 DOI: 10.1186/1476-511x-10-84] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2011] [Accepted: 05/20/2011] [Indexed: 11/10/2022] Open
Abstract
Fatty acid 2-hydroxylase (FA2H) is the enzyme responsible for the hydroxylation of free fatty acids prior to their incorporation into 2-hydroxylated sphingolipids, which are the major constituents of the myelin leaflet. Mutated FA2H has been associated with neurodegenerative diseases. Decreased FA2H activity was demonstrated only in vitro, but not in patient tissues. In this study we characterized the 2-hydroxylated sphingomyelin (SM) profiles in blood and fibroblasts from patients harboring a deleterious FA2H mutatation, and found that hydroxylated fatty acid sphingomyelin is present in normal amounts in patient lymphocytes, but decreased to a different extent in fibroblasts and erythrocytes.
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Affiliation(s)
- Phyllis Dan
- Department of Genetics and Metabolic Diseases and the Monique and Jacques Roboh Department of Genetic Research, Hadassah-Hebrew University Medical Center, Jerusalem, Israel
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157
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Kolter T. A view on sphingolipids and disease. Chem Phys Lipids 2011; 164:590-606. [PMID: 21570958 DOI: 10.1016/j.chemphyslip.2011.04.013] [Citation(s) in RCA: 57] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2011] [Revised: 04/26/2011] [Accepted: 04/28/2011] [Indexed: 12/27/2022]
Abstract
Sphingolipid and glycosphingolipid levels and expression of sphingolipid metabolizing enzymes are altered in a variety of diseases or in response to drug treatment. Inherited defects of enzymes and other proteins required for the lysosomal degradation of these lipids lead to human sphingolipidoses. Also genetic defects that affect sphingolipid biosynthesis are known. Although the molecular details are often far from clear, (glyco)sphingolipids have been implicated to play a role in atherosclerosis, insulin resistance, cancer, and infections by pathogens. More general aspects of selected diseases are discussed.
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Affiliation(s)
- Thomas Kolter
- LiMES-Laboratory of Lipid Biochemistry, Kekulé-Institut für Organische Chemie und Biochemie der Universität, Bonn, Germany.
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158
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Meixner M, Jungnickel J, Grothe C, Gieselmann V, Eckhardt M. Myelination in the absence of UDP-galactose:ceramide galactosyl-transferase and fatty acid 2 -hydroxylase. BMC Neurosci 2011; 12:22. [PMID: 21366909 PMCID: PMC3053264 DOI: 10.1186/1471-2202-12-22] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2010] [Accepted: 03/02/2011] [Indexed: 01/06/2023] Open
Abstract
BACKGROUND The sphingolipids galactosylceramide (GalCer) and sulfatide are major myelin components and are thought to play important roles in myelin function. The importance of GalCer and sulfatide has been validated using UDP-galactose:ceramide galactosyltransferase-deficient (Cgt-/-) mice, which are impaired in myelin maintenance. These mice, however, are still able to form compact myelin. Loss of GalCer and sulfatide in these mice is accompanied by up-regulation of 2-hydroxylated fatty acid containing (HFA)-glucosylceramide in myelin. This was interpreted as a partial compensation of the loss of HFA-GalCer, which may prevent a more severe myelin phenotype. In order to test this hypothesis, we have generated Cgt-/- mice with an additional deletion of the fatty acid 2-hydroxylase (Fa2h) gene. RESULTS Fa2h-/-/Cgt-/- double-deficient mice lack sulfatide, GalCer, and in addition HFA-GlcCer and sphingomyelin. Interestingly, compared to Cgt-/- mice the amount of GlcCer in CNS myelin was strongly reduced in Fa2h-/-/Cgt-/- mice by more than 80%. This was accompanied by a significant increase in sphingomyelin, which was the predominant sphingolipid in Fa2h-/-/Cgt-/- mice. Despite these significant changes in myelin sphingolipids, compact myelin was formed in Fa2h-/-/Cgt-/- mice, and g-ratios of myelinated axons in the spinal cord of 4-week-old Fa2h-/-/Cgt-/- mice did not differ significantly from that of Cgt-/- mice, and there was no obvious phenotypic difference between Fa2h-/-/Cgt-/- and Cgt-/- mice CONCLUSIONS These data show that compact myelin can be formed with non-hydroxylated sphingomyelin as the predominant sphingolipid and suggest that the presence of HFA-GlcCer and HFA-sphingomyelin in Cgt-/- mice does not functionally compensate the loss of HFA-GalCer.
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Affiliation(s)
- Marion Meixner
- Institute of Biochemistry and Molecular Biology, University of Bonn, Germany
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159
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Ekholm O, Jaikishan S, Lönnfors M, Nyholm TK, Slotte JP. Membrane bilayer properties of sphingomyelins with amide-linked 2- or 3-hydroxylated fatty acids. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2011; 1808:727-32. [DOI: 10.1016/j.bbamem.2010.12.006] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/30/2010] [Revised: 12/04/2010] [Accepted: 12/07/2010] [Indexed: 01/21/2023]
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160
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Barrier L, Fauconneau B, Noël A, Ingrand S. Ceramide and Related-Sphingolipid Levels Are Not Altered in Disease-Associated Brain Regions of APP and APP/PS1 Mouse Models of Alzheimer's Disease: Relationship with the Lack of Neurodegeneration? Int J Alzheimers Dis 2010; 2011:920958. [PMID: 21234372 PMCID: PMC3014734 DOI: 10.4061/2011/920958] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2010] [Accepted: 11/16/2010] [Indexed: 02/06/2023] Open
Abstract
There is evidence linking sphingolipid abnormalities, APP processing, and neuronal death in Alzheimer's disease (AD). We previously reported a strong elevation of ceramide levels in the brain of the APP(SL)/PS1Ki mouse model of AD, preceding the neuronal death. To extend these findings, we analyzed ceramide and related-sphingolipid contents in brain from two other mouse models (i.e., APP(SL) and APP(SL)/PS1(M146L)) in which the time-course of pathology is closer to that seen in most currently available models. Conversely to our previous work, ceramides did not accumulate in disease-associated brain regions (cortex and hippocampus) from both models. However, the APP(SL)/PS1Ki model is unique for its drastic neuronal loss coinciding with strong accumulation of neurotoxic Aβ isoforms, not observed in other animal models of AD. Since there are neither neuronal loss nor toxic Aβ species accumulation in APP(SL) mice, we hypothesized that it might explain the lack of ceramide accumulation, at least in this model.
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Affiliation(s)
- Laurence Barrier
- Groupe de Recherche sur le Vieillissement Cérébral, GreViC EA 3808, Faculté de Médecine et de Pharmacie, 6 rue de la Milétrie, BP 199, 86034 Poitiers Cedex, France
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161
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Kruer MC, Paisán-Ruiz C, Boddaert N, Yoon MY, Hama H, Gregory A, Malandrini A, Woltjer RL, Munnich A, Gobin S, Polster BJ, Palmeri S, Edvardson S, Hardy J, Houlden H, Hayflick SJ. Defective FA2H leads to a novel form of neurodegeneration with brain iron accumulation (NBIA). Ann Neurol 2010; 68:611-8. [PMID: 20853438 DOI: 10.1002/ana.22122] [Citation(s) in RCA: 160] [Impact Index Per Article: 11.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
OBJECTIVE Neurodegeneration with brain iron accumulation (NBIA) represents a distinctive phenotype of neurodegenerative disease for which several causative genes have been identified. The spectrum of neurologic disease associated with mutations in NBIA genes is broad, with phenotypes that range from infantile neurodegeneration and death in childhood to adult-onset parkinsonism-dystonia. Here we report the discovery of a novel gene that leads to a distinct form of NBIA. METHODS Using autozygosity mapping and candidate gene sequencing, we identified mutations in the fatty acid hydroxylase gene FA2H, newly implicating abnormalities of ceramide metabolism in the pathogenesis of NBIA. RESULTS Neuroimaging demonstrated T2 hypointensity in the globus pallidus, confluent T2 white matter hyperintensities, and profound pontocerebellar atrophy in affected members of two families. Phenotypically, affected family members exhibited spastic quadriparesis, ataxia, and dystonia with onset in childhood and episodic neurological decline. Analogous to what has been reported previously for PLA2G6, the phenotypic spectrum of FA2H mutations is diverse based on our findings and those of prior investigators, because FA2H mutations have been identified in both a form of hereditary spastic paraplegia (SPG35) and a progressive familial leukodystrophy. INTERPRETATION These findings link white matter degeneration and NBIA for the first time and implicate new signaling pathways in the genesis of NBIA.
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Affiliation(s)
- Michael C Kruer
- Division of Developmental Pediatrics, Child Development and Rehabilitation Center, Oregon Health & Science University, Portland, OR 97239, USA
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162
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Szulc ZM, Bai A, Bielawski J, Mayroo N, Miller DE, Gracz H, Hannun YA, Bielawska A. Synthesis, NMR characterization and divergent biological actions of 2'-hydroxy-ceramide/dihydroceramide stereoisomers in MCF7 cells. Bioorg Med Chem 2010; 18:7565-79. [PMID: 20851613 PMCID: PMC2956829 DOI: 10.1016/j.bmc.2010.08.050] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2010] [Revised: 08/25/2010] [Accepted: 08/26/2010] [Indexed: 02/09/2023]
Abstract
A straightforward method for the simultaneous preparation of (2S,3R,2'R)- and (2S,3R,2'S)-2'-hydroxy-ceramides (2'-OHCer) from (2S,3R)-sphingosine acetonide precursors and racemic mixtures of 2-hydroxy fatty acids (2-OHFAs) is described. The obtained 2'-OH-C4-, -C6-, -C12-, -C16-Cer and 2'-OH-C6-dhCer pairs of diastereoisomers were characterized thoroughly by TLC, MS, NMR, and optical rotation. Dynamic and multidimensional NMR studies provided evidence that polar interfaces of 2'-OHCers are extended and more rigid than observed for the corresponding non-hydroxylated analogs. Stereospecific profile on growth suppression of MCF7 cells was observed for (2'R)- and (2'S)-2'-OH-C6-Cers and their dihydro analogs. The (2'R)-isomers were more active than the (2'S)-isomers (IC(50) ∼3 μM/8 μM and IC(50) ∼8 μM/12 μM, respectively), surpassing activity of the ordinary C6-Cer (IC(50) ∼12 μM) and C6-dhCer (IC(50) ∼38 μM). Neither isomer of 2'-OH-C6-Cers and 2'-OH-C6-dhCers was metabolized to their cellular long chain 2'-OH-homologs. Surprisingly, the most active (2'R)-isomers did not influence the levels of the cellular Cers nor dhCers. Contrary to this, the (2'S)-isomers generated cellular Cers and dhCers efficiently. In comparison, the ordinary C6-Cer and C6-dhCer also significantly increased the levels of their cellular long chain homologs. These peculiar anabolic responses and SAR data suggest that (2'R)-2'-OHCers/dhCers may interact with some distinct cellular regulatory targets in a specific and more effective manner than their non-hydroxylated analogs. Thus, stereoisomers of 2'-OHCers can be potentially utilized as novel molecular tools to study lipid-protein interactions, cell signaling phenomena and to understand the role of hydroxylated sphingolipids in cancer biology, pathogenesis and therapy.
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Affiliation(s)
- Zdzislaw M. Szulc
- Lipidomics Shared Resource, Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425
| | - Aiping Bai
- Lipidomics Shared Resource, Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425
| | - Jacek Bielawski
- Lipidomics Shared Resource, Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425
| | - Nalini Mayroo
- Lipidomics Shared Resource, Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425
| | - Doreen E. Miller
- Lipidomics Shared Resource, Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425
- Roche Carolina, Inc., Florence, SC 29506
| | - Hanna Gracz
- Department of Molecular and Structural Biochemistry, North Carolina State University, Raleigh, NC 27695, USA
| | - Yusuf A. Hannun
- Lipidomics Shared Resource, Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425
| | - Alicja Bielawska
- Lipidomics Shared Resource, Department of Biochemistry and Molecular Biology, Medical University of South Carolina, Charleston, SC 29425
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163
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Zanetti SR, de Los Ángeles Monclus M, Rensetti DE, Fornés MW, Aveldaño MI. Ceramides with 2-hydroxylated, very long-chain polyenoic fatty acids in rodents: From testis to fertilization-competent spermatozoa. Biochimie 2010; 92:1778-86. [PMID: 20831891 DOI: 10.1016/j.biochi.2010.08.012] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2010] [Accepted: 08/13/2010] [Indexed: 10/19/2022]
Abstract
Sphingolipids from rodent testis and spermatozoa are known to contain non-hydroxylated (N-) and 2-hydroxylated (2-OH) very-long-chain polyunsaturated fatty acids (VLCPUFA). In this study, the contribution of species with each type of fatty acids to the total ceramides (Cer) and sphingomyelins (SM) was investigated in rat and mouse testis and in rat spermatozoa. The major VLCPUFA in both lipids of testis were N- and 2-OH versions of 28:4n-6, 30:5n-6 and 32:5n-6 in the rat, and predominantly of 30:5n-6 in the mouse. Absent altogether from rat pre-puberal testes, SM and Cer with N-VLCPUFA appeared 10 days earlier than those with 2-OH VLCPUFA in postnatal development, in association with germ cell differentiation. Conversely, in adult fertile rats that were gradually deprived of germ cells in vivo after treatment with doxorubicin, SM and Cer with N-VLCPUFA decreased earlier than their 2-OH counterparts, and neither was present in aspermatogenic testes. In rat epididymal spermatozoa, the content of Cer prevailed over that of SM and 2-OH VLCPUFA prevailed over N-VLCPUFA in both lipids. In mature gametes, the acrosomal reaction resulted in an almost complete hydrolysis of the species of SM that contain both types of VLCPUFA to produce the corresponding Cer. Ceramides are biosynthetic precursors of SM in the testis, but themselves final products in spermatozoa. VLCPUFA-rich SM and Cer are thus produced in germ cells with the teleological objective of fulfilling their ultimate physiological role in spermatozoa that are apt and ready to fertilize an oocyte.
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Affiliation(s)
- Samanta R Zanetti
- Instituto de Investigaciones Bioquímicas de Bahía Blanca, Consejo Nacional de Investigaciones Científicas y Técnicas and Universidad Nacional del Sur, 8000 Bahía Blanca, Argentina
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164
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Guo L, Zhou D, Pryse KM, Okunade AL, Su X. Fatty acid 2-hydroxylase mediates diffusional mobility of Raft-associated lipids, GLUT4 level, and lipogenesis in 3T3-L1 adipocytes. J Biol Chem 2010; 285:25438-47. [PMID: 20519515 PMCID: PMC2919107 DOI: 10.1074/jbc.m110.119933] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2010] [Revised: 05/26/2010] [Indexed: 01/27/2023] Open
Abstract
Straight chain fatty acid alpha-oxidation increases during differentiation of 3T3-L1 adipocytes, leading to a marked accumulation of odd chain length fatty acyl moieties. Potential roles of this pathway in adipocyte differentiation and lipogenesis are unknown. Mammalian fatty acid 2-hydroxylase (FA2H) was recently identified and suggested to catalyze the initial step of straight chain fatty acid alpha-oxidation. Accordingly, we examined whether FA2H modulates adipocyte differentiation and lipogenesis in mature adipocytes. FA2H level markedly increases during differentiation of 3T3-L1 adipocytes, and small interfering RNAs against FA2H inhibit the differentiation process. In mature adipocytes, depletion of FA2H inhibits basal and insulin-stimulated glucose uptake and lipogenesis, which are partially rescued by the enzymatic product of FA2H, 2-hydroxy palmitic acid. Expression of fatty-acid synthase and SCD1 was decreased in FA2H-depleted cells, and levels of GLUT4 and insulin receptor proteins were reduced. 2-Hydroxy fatty acids are enriched in cellular sphingolipids, which are components of membrane rafts. Accelerated diffusional mobility of raft-associated lipids was shown to enhance degradation of GLUT4 and insulin receptor in adipocytes. Consistent with this, depletion of FA2H appeared to increase raft lipid mobility as it significantly accelerated the rates of fluorescence recovery after photobleaching measurements of lipid rafts labeled with Alexa 488-conjugated cholera toxin subunit B. Moreover, the enhanced recovery rates were partially reversed by treatment with 2-hydroxy palmitic acid. In conclusion, our findings document the novel role of FA2H in adipocyte lipogenesis possibly by modulation of raft fluidity and level of GLUT4.
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Affiliation(s)
- Lin Guo
- From the Department of Internal Medicine, Center for Human Nutrition, and
| | - Dequan Zhou
- From the Department of Internal Medicine, Center for Human Nutrition, and
| | | | - Adewole L. Okunade
- From the Department of Internal Medicine, Center for Human Nutrition, and
| | - Xiong Su
- From the Department of Internal Medicine, Center for Human Nutrition, and
- Cell Biology and Physiology, Washington University School of Medicine, St. Louis, Missouri 63110
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