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Helgudóttir SS, Mørkholt AS, Lichota J, Bruun-Nyzell P, Andersen MC, Kristensen NMJ, Johansen AK, Zinn MR, Jensdóttir HM, Nieland JDV. Rethinking neurodegenerative diseases: neurometabolic concept linking lipid oxidation to diseases in the central nervous system. Neural Regen Res 2024; 19:1437-1445. [PMID: 38051885 PMCID: PMC10883494 DOI: 10.4103/1673-5374.387965] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Accepted: 09/21/2023] [Indexed: 12/07/2023] Open
Abstract
ABSTRACT Currently, there is a lack of effective medicines capable of halting or reversing the progression of neurodegenerative disorders, including amyotrophic lateral sclerosis, Parkinson's disease, multiple sclerosis, or Alzheimer's disease. Given the unmet medical need, it is necessary to reevaluate the existing paradigms of how to target these diseases. When considering neurodegenerative diseases from a systemic neurometabolic perspective, it becomes possible to explain the shared pathological features. This innovative approach presented in this paper draws upon extensive research conducted by the authors and researchers worldwide. In this review, we highlight the importance of metabolic mitochondrial dysfunction in the context of neurodegenerative diseases. We provide an overview of the risk factors associated with developing neurodegenerative disorders, including genetic, epigenetic, and environmental factors. Additionally, we examine pathological mechanisms implicated in these diseases such as oxidative stress, accumulation of misfolded proteins, inflammation, demyelination, death of neurons, insulin resistance, dysbiosis, and neurotransmitter disturbances. Finally, we outline a proposal for the restoration of mitochondrial metabolism, a crucial aspect that may hold the key to facilitating curative therapeutic interventions for neurodegenerative disorders in forthcoming advancements.
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Affiliation(s)
| | | | - Jacek Lichota
- Molecular Pharmacology Group, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | | | - Mads Christian Andersen
- Molecular Pharmacology Group, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Nanna Marie Juhl Kristensen
- Molecular Pharmacology Group, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Amanda Krøger Johansen
- Molecular Pharmacology Group, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Mikela Reinholdt Zinn
- Molecular Pharmacology Group, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - Hulda Maria Jensdóttir
- Molecular Pharmacology Group, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
| | - John Dirk Vestergaard Nieland
- 2N Pharma ApS, NOVI Science Park, Aalborg, Denmark
- Molecular Pharmacology Group, Department of Health Science and Technology, Aalborg University, Aalborg, Denmark
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2
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Mørkholt AS, Oklinski MK, Larsen A, Bockermann R, Issazadeh-Navikas S, Nieland JGK, Kwon TH, Corthals A, Nielsen S, Nieland JDV. Pharmacological inhibition of carnitine palmitoyl transferase 1 inhibits and reverses experimental autoimmune encephalitis in rodents. PLoS One 2020; 15:e0234493. [PMID: 32520953 PMCID: PMC7286491 DOI: 10.1371/journal.pone.0234493] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2019] [Accepted: 05/26/2020] [Indexed: 02/01/2023] Open
Abstract
Multiple sclerosis (MS) is a neurodegenerative disease characterized by demyelination and inflammation. Dysregulated lipid metabolism and mitochondrial dysfunction are hypothesized to play a key role in MS. Carnitine Palmitoyl Transferase 1 (CPT1) is a rate-limiting enzyme for beta-oxidation of fatty acids in mitochondria. The therapeutic effect of pharmacological CPT1 inhibition with etomoxir was investigated in rodent models of myelin oligodendrocyte glycoprotein- and myelin basic protein-induced experimental autoimmune encephalitis (EAE). Mice receiving etomoxir showed lower clinical score compared to placebo, however this was not significant. Rats receiving etomoxir revealed significantly lower clinical score and lower body weight compared to placebo group. When comparing etomoxir with interferon-β (IFN-β), IFN-β had no significant therapeutic effects, whereas etomoxir treatment starting at day 1 and 5 significantly improved the clinical scores compared to the IFN-β and the placebo group. Immunohistochemistry and image assessments of brain sections from rats with EAE showed higher myelination intensity and decreased expression of CPT1A in etomoxir-treated rats compared to placebo group. Moreover, etomoxir mediated increased interleukin-4 production and decreased interleukin-17α production in activated T cells. In conclusion, CPT1 is a key protein in the pathogenesis of EAE and MS and a crucial therapeutic target for the treatment.
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Affiliation(s)
| | | | - Agnete Larsen
- Department of Biomedicine, Aarhus University, Aarhus C, Denmark
| | - Robert Bockermann
- Biotech Research and Innovation Centre, Copenhagen University, Copenhagen N, Denmark
| | | | | | - Tae-Hwan Kwon
- Department of Biochemistry and Cell Biology, School of Medicine, Kyungpook National University, Taegu, Korea
| | - Angelique Corthals
- Department of Science, John Jay College of Criminal Justice, City University of New York, New York, New York, United States of America
| | - Søren Nielsen
- Department of Health Science and Technology, Aalborg University, Aalborg, Denmark.,Meta-IQ, ApS, Aarhus C, Denmark
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3
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Monteiro HMC, de Mendonça DC, Sousa MSB, Amancio-dos-Santos A. Physical exercise counteracts the increase in velocity of propagation of cortical spreading depression imposed by early over-nutrition in rats. Nutr Neurosci 2018; 23:161-169. [DOI: 10.1080/1028415x.2018.1481180] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/14/2022]
Affiliation(s)
| | - Débora Carneiro de Mendonça
- Departamento de Fisiologia e Farmacologia, Centro de Biociências, Universidade Federal de Pernambuco, Recife, PE 50740-600, Brazil
| | - Mariana Séfora Bezerra Sousa
- Departamento de Nutrição, Centro de Ciências da Saúde, Universidade Federal de Pernambuco, Recife, PE 50670-901, Brazil
| | - Angela Amancio-dos-Santos
- Departamento de Fisiologia e Farmacologia, Centro de Biociências, Universidade Federal de Pernambuco, Recife, PE 50740-600, Brazil
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Planey SL, Zacharias DA. Palmitoyl acyltransferases, their substrates, and novel assays to connect them (Review). Mol Membr Biol 2009; 26:14-31. [DOI: 10.1080/09687680802646703] [Citation(s) in RCA: 34] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Ducker CE, Griffel LK, Smith RA, Keller SN, Zhuang Y, Xia Z, Diller JD, Smith CD. Discovery and characterization of inhibitors of human palmitoyl acyltransferases. Mol Cancer Ther 2006; 5:1647-59. [PMID: 16891450 PMCID: PMC2888271 DOI: 10.1158/1535-7163.mct-06-0114] [Citation(s) in RCA: 70] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The covalent attachment of palmitate to specific proteins by the action of palmitoyl acyltransferases (PAT) plays critical roles in the biological activities of several oncoproteins. Two PAT activities are expressed by human cells: type 1 PATs that modify the farnesyl-dependent palmitoylation motif found in H- and N-Ras, and type 2 PATs that modify the myristoyl-dependent palmitoylation motif found in the Src family of tyrosine kinases. We have previously shown that the type 1 PAT HIP14 causes cellular transformation. In the current study, we show that mRNA encoding HIP14 is up-regulated in a number of types of human tumors. To assess the potential of HIP14 and other PATs as targets for new anticancer drugs, we developed three cell-based assays suitable for high-throughput screening to identify inhibitors of these enzymes. Using these screens, five chemotypes, with activity toward either type 1 or type 2 PAT activity, were identified. The activity of the hits were confirmed using assays that quantify the in vitro inhibition of PAT activity, as well as a cell-based assay that determines the abilities of the compounds to prevent the localization of palmitoylated green fluorescent proteins to the plasma membrane. Representative compounds from each chemotype showed broad antiproliferative activity toward a panel of human tumor cell lines and inhibited the growth of tumors in vivo. Together, these data show that PATs, and HIP14 in particular, are interesting new targets for anticancer compounds, and that small molecules with such activity can be identified by high-throughput screening.
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Affiliation(s)
- Charles E Ducker
- Department of Pharmaceutical Sciences, Medical University of South Carolina, 280 Calhoun Street, Box 250140, Charleston, SC 29425, USA.
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Goswami R, Ahmed M, Kilkus J, Han T, Dawson SA, Dawson G. Differential regulation of ceramide in lipid-rich microdomains (rafts): Antagonistic role of palmitoyl:protein thioesterase and neutral sphingomyelinase 2. J Neurosci Res 2005; 81:208-17. [PMID: 15929065 DOI: 10.1002/jnr.20549] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Cell differentiation and myelination involve a fine balance between stasis and programmed cell death, yet the genes that regulate this have not been clearly defined. We therefore studied two key gene products involved in oligodendrocyte plasma membrane lipid metabolism and their antagonistic role in ceramide-mediated cell death signaling. Overexpression of palmitoyl:protein thioesterase (PPT1; verified by Western blot of the V5-tagged protein and increased enzyme activity) resulted in decreased ceramide in the detergent-resistant microdomain (DRM, or raft) relative to cholesterol and sphingomyelin (SM). This PPT1 overexpression also resulted in protection against cell death induced by either staurosporine or C(2)-ceramide. In contrast, overexpression of neutral sphingomyelinase 2 (NSMase2; verified by Western blot of the FLAG-tagged protein and increased enzyme activity) resulted in increased membrane NSMase and increased ceramide in rafts relative to cholesterol and SM. The difference in SM and ceramide turnover was quantitated by [(3)H]palmitate pulse-chase labeling. Furthermore, when NBD-SM was added to cells, it was hydrolyzed by NSMase-transfected cells at more than twofold the rate in untransfected cells. NSMase2 overexpression enhanced cell death induced by staurosporine or C(2)-ceramide, in contrast to the protective effect of PPT1 overexpression. The presence of a fraction of both PPT1 and NSMase2 in rafts together with their substrates (palmitoylated proteins and SM, respectively) suggests a mechanism for dynamic palmitoylation/depalmitoylation of certain proteins in controlling cell death via NSMase activation.
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Affiliation(s)
- R Goswami
- Departments of Pediatrics, Biochemistry and Molecular Biology, University of Chicago, Chicago, IL 60637, USA
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Dawson G, Dawson SA, Marinzi C, Dawson PE. Anti-tumor promoting effects of palmitoyl: protein thioesterase inhibitors against a human neurotumor cell line. Cancer Lett 2002; 187:163-8. [PMID: 12359364 DOI: 10.1016/s0304-3835(02)00403-2] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Inhibiting the depalmitoylation of proteins disrupts cell survival signaling in tumor cells and leads to increased cell death. We chemically synthesized a non-hydrolyzable analog of the palmitoyl-cysteine thioester linkage (AcG-alpha-ketoamido-palmitoyl diamino propionate-VKIKK) (DAPKA) and showed that it inhibits palmitoyl:protein thioesterase (PPT1) in an in vitro assay using a specific fluorescent-based (4-methylumbelliferyl-beta-gluco-6-thiopalmitate) assay. We then showed that it killed cultured tumor cells and enhanced the killing of neurotumor cells by chemotherapeutic drugs such as etoposide and adriamycin. Overexpression of PPT1 protected against apoptosis induced by etoposide and the ketoamide and the inhibitory effect of the two was additive.
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Affiliation(s)
- Glyn Dawson
- Department of Pediatrics, University of Chicago, Chicago, IL 60637, USA.
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Spörkel O, Uschkureit T, Büssow H, Stoffel W. Oligodendrocytes expressing exclusively the DM20 isoform of the proteolipid protein gene: myelination and development. Glia 2002; 37:19-30. [PMID: 11746780 DOI: 10.1002/glia.10014] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
Oligodendroglia and Schwann cells synthesize myelin-specific proteins and lipids for the assembly of the highly organized myelin membrane of the motor-sensory axons in the central (CNS) and peripheral nervous system (PNS), respectively, allowing rapid saltatory conduction. The isoforms of the main myelin proteins, the peripheral myelin basic isoproteins (MBP) and the integral proteolipid proteins, PLP and DM20, arise from alternative splicing. Activation of a cryptic splice site in exon III of plp leads to the deletion of 105 bp encoding the PLP-specific 35 amino acid residues within the cytosolic loop 3 of the four-transmembrane domain (TMD) integral membrane protein. To study the different proposed functions of DM20 during the development of oligodendrocytes and in myelination, we targeted the plp locus in embryonic stem cells by homologous recombination by a construct, which allows solely the expression of the DM20 specific exon III sequence. The resulting dm20(only) mouse line expresses exclusively DM20 isoprotein, which is functionally assembled into the membrane, forming a highly ordered and tightly compacted myelin sheath. The truncated cytosolic loop devoid of the PLP-specific 35 amino acid residues, including two thioester groups, had no impact on the periodicity of CNS myelin. In contrast to the PLP/DM20-deficient mouse, mutant CNS of dm20(only) mice showed no axonal swellings and neurodegeneration but a slow punctuated disintegration of the compact layers of the myelin sheath and a rare oligodendrocyte death developing with aging.
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Affiliation(s)
- Olaf Spörkel
- Laboratory of Molecular Neuroscience, University of Cologne, Cologne, Germany
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Robert F, Guennoun R, Désarnaud F, Do-Thi A, Benmessahel Y, Baulieu EE, Schumacher M. Synthesis of progesterone in Schwann cells: regulation by sensory neurons. Eur J Neurosci 2001; 13:916-24. [PMID: 11264664 DOI: 10.1046/j.0953-816x.2001.01463.x] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
In peripheral nerves, progesterone synthesized by Schwann cells has been implicated in myelination. In spite of such an important function, little is known of the regulation of progesterone biosynthesis in the nervous system. We show here that in rat Schwann cells, expression of the 3 beta-hydroxysteroid dehydrogenase and formation of progesterone are dependent on neuronal signal. Levels of 3 beta-hydroxysteroid dehydrogenase mRNA and synthesis of [3H]progesterone from [3H]pregnenolone were low in purified Schwann cells prepared from neonatal rat sciatic nerves. However, when Schwann cells were cultured in contact with sensory neurons, both expression and activity of the 3 beta-hydroxysteroid dehydrogenase were induced. Regulation of 3 beta-hydroxysteroid dehydrogenase expression by neurons was also demonstrated in vivo in the rat sciatic nerve. 3 beta-hydroxysteroid dehydrogenase mRNA was present in the intact nerve, but could no longer be detected 3 or 6 days after cryolesion, when axons had degenerated. After 15 days, when Schwann cells made new contact with the regenerating axons, the enzyme was re-expressed. After nerve transection, which does not allow axonal regeneration, 3 beta-hydroxysteroid dehydrogenase mRNA remained undetectable. The regulation of 3 beta-hydroxysteroid dehydrogenase mRNA after lesion was similar to the regulation of myelin protein zero (P0) and peripheral myelin protein 22 (PMP22) mRNAs, supporting an important role of locally formed progesterone in myelination.
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Affiliation(s)
- F Robert
- INSERM U488, 80, rue du Général Leclerc, 94276 Bicêtre, France
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Bizzozero OA, Bixler HA, Davis JD, Espinosa A, Messier AM. Chemical deacylation reduces the adhesive properties of proteolipid protein and leads to decompaction of the myelin sheath. J Neurochem 2001; 76:1129-41. [PMID: 11181833 DOI: 10.1046/j.1471-4159.2001.00116.x] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Myelin proteolipid protein (PLP) contains thioester-bound, long-chain fatty acids which are known to influence the structure of the molecule. To gain further insights into the role of this post-translational modification, we studied the effect that chemical deacylation of PLP had on the morphology of myelin and on the protein's ability to mediate the clustering of lipid vesicles. Incubation of rat optic nerves in isoosmotic solutions containing 100 mM hydroxylamine (HA) pH 7.4 led to deacylation of PLP and decompaction of myelin lamellae at the level of the intraperiod line. Incubation of nerves with milder nucleophilic agents (Tris and methylamine) or diluted HA, conditions that do not remove protein-bound fatty acids, caused no alterations in myelin structure. Other possible effects of HA which could have affected myelin compaction indirectly were ruled out. Incubation of optic nerves with 50 mM dithioerythritol (DTE) also led to the splitting of the myelin intraperiod line and this change again coincided with the removal of fatty acids. In addition, the apparently compacted CNS myelin in the PLP-less myelin-deficient rat, like that in tissue containing deacylated PLP, was readily decompacted upon incubation in isoosmotic buffers, suggesting that the function of PLP as a stabilizer of the interlamellar attachment is, at least in part, mediated by fatty acylation. Furthermore, in contrast to the native protein, PLP deacylated with either HA or DTE failed to induce the clustering of phosphatidylcholine/cholesterol vesicles in vitro. This phenomenon is not due to side-effects of the deacylation procedure since, upon partial repalmitoylation, the protein recovered most of its original vesicle-clustering activity. Collectively, these findings suggest that palmitoylation, by influencing the adhesive properties of PLP, is important for stabilizing the multilamellar structure of myelin.
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Affiliation(s)
- O A Bizzozero
- Department of Cell Biology and Physiology, University of New Mexico-Health Sciences Center, Albuquerque, New Mexico, USA.
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11
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Cho S, Dawson G. Palmitoyl protein thioesterase 1 protects against apoptosis mediated by Ras-Akt-caspase pathway in neuroblastoma cells. J Neurochem 2000; 74:1478-88. [PMID: 10737604 DOI: 10.1046/j.1471-4159.2000.0741478.x] [Citation(s) in RCA: 60] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Palmitoyl protein thioesterase (PPT) 1 is an enzyme involved in deacylation of palmitoylated proteins. A deficiency in PPT1 results in a genetic disease, infantile neuronal ceroid lipofuscinosis, associated with massive death of cortical neurons. The role of PPT1 in neuronal survival and apoptosis was studied in human neuroblastoma (LA-N-5) cells overexpressing PPT1. Overexpression of PPT1 was shown both by the 200-350% increase in depalmitoylating activity over basal level (as determined by an in vitro PPT assay) and by western blot analysis of transiently expressed epitope-tagged PPT1. Overexpressed PPT1 showed the same acidic pH optimum (pH 4.0) as the endogenous enzyme, when assayed with a P0-derived octapeptide substrate, and reduced the growth rate by 30%. LA-N-5 cells underwent apoptosis, as evidenced by increased caspase 3-like activity and increased DNA fragmentation, when challenged with either C2-ceramide or a phosphatidylinositol 3-kinase inhibitor (LY294002). Overexpression of PPT1 inhibited this C2-ceramide- or LY294002-mediated activation of caspase-3 by 50%. There was also a concomitant decrease in DNA fragmentation and cell death. Consistent with increased resistance to apoptosis, we found increased phosphorylation of the antiapoptotic protein Akt (protein kinase B) in PPT1-overexpressing cells. p21Ras is known to be dynamically palmitoylated and depalmitoylated and is involved in both growth and cell death. The C2-ceramide-induced membrane association of p21Ras was reduced by 30-50% in PPT1-overexpressing cells compared with control. PPT overexpression also led to reduced membrane association of another palmitoylated protein, GAP-43, a neuron-specific protein. Our studies suggest that protein palmitoylation could be a physiological regulator of apoptosis.
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Affiliation(s)
- S Cho
- Department of Pediatrics, University of Chicago, Illinois, USA
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12
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Faergeman NJ, Ballegaard T, Knudsen J, Black PN, DiRusso C. Possible roles of long-chain fatty Acyl-CoA esters in the fusion of biomembranes. Subcell Biochem 2000; 34:175-231. [PMID: 10808334 DOI: 10.1007/0-306-46824-7_5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/14/2023]
Affiliation(s)
- N J Faergeman
- Department of Biochemistry and Molecular Biology, Albany Medical College, New York 12208, USA
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13
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Bizzozero OA, Sanchez P, Tetzloff SU. Effect of ATP depletion on the palmitoylation of myelin proteolipid protein in young and adult rats. J Neurochem 1999; 72:2610-6. [PMID: 10349873 DOI: 10.1046/j.1471-4159.1999.0722610.x] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
The present study was designed to determine whether the palmitoylation of the hydrophobic myelin proteolipid protein (PLP) is dependent on cellular energy. To this end, brain slices from 20- and 60-day-old rats were incubated with [3H]palmitate for 1 h in the presence or absence of various metabolic poisons. In adult rats, the inhibition of mitochondrial ATP production with KCN (5 mM), oligomycin (10 microM), or rotenone (10 microM) reduced the incorporation of [3H]palmitate into fatty acyl-CoA and glycerolipids by 50-60%, whereas the labeling of PLP was unaltered. Incubation in the presence of rotenone (10 microM) plus NaF (5 mM) abolished the synthesis of acyl-CoA and lipid palmitoylation, but the incorporation of [3H]palmitate into PLP was still not different from that in controls. In rapidly myelinating animals, the inhibition of both mitochondrial electron transport and glycolysis obliterated the palmitoylation of lipids but reduced that of PLP by only 40%. PLP acylation was reduced to a similar extent when slices were incubated for up to 3 h, indicating that exogenously added palmitate is incorporated into PLP by ATP-dependent and ATP-independent mechanisms. Determination of the number of PLP molecules modified by each of these reactions during development suggests that the ATP-dependent process is important during the formation and/or compaction of the myelin sheath, whereas the ATP-independent mechanism is likely to play a role in myelin maintenance, perhaps by participating in the periodic repair of thioester linkages between the fatty acids and the protein.
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Affiliation(s)
- O A Bizzozero
- Department of Cell Biology and Physiology, University of New Mexico Health Sciences Center, Albuquerque 87131-5218, USA
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Tetzloff SU, Bizzozero OA. Palmitoylation of proteolipid protein from rat brain myelin using endogenously generated 18O-fatty acids. J Biol Chem 1998; 273:279-85. [PMID: 9417076 DOI: 10.1074/jbc.273.1.279] [Citation(s) in RCA: 13] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Proteolipid protein (PLP), the major protein of central nervous system myelin, contains covalently bound fatty acids, predominantly palmitic acid. This study adapts a stable isotope technique (Kuwae, T., Schmid, P. C., Johnson, S. B., and Schmid, H. O. (1990) J. Biol. Chem. 265, 5002-5007) to quantitatively determine the minimal proportion of PLP molecules which undergo palmitoylation. In these experiments, brain white matter slices from 20-day-old rats were incubated for up to 6 h in a physiological buffer containing 50% H218O. The uptake of 18O into the carbonyl groups of fatty acids derived from PLP, phospholipids, and the free fatty acid pool was measured by gas-liquid chromatography/mass spectrometry of the respective methyl esters. Palmitic acid derived from PLP acquired increasing amounts of 18O, ending with 2.9% 18O enrichment after 6 h of incubation. 18O incorporation into myelin free palmitic acid also increased over the course of the incubation (67.2% 18O enrichment). After correcting for the specific activity of the 18O-enriched free palmitic acid pool, 7.6% of the PLP molecules were found to acquire palmitic acid in 6 h. This value is not only too large to be the result of the palmitoylation of newly synthesized PLP molecules, it was also unchanged upon the inhibition of protein synthesis with cycloheximide. 18O enrichment in less actively myelinating 60-day-old rats was significantly reduced. In conclusion, our experiments suggest that a substantial proportion of PLP molecules acquire palmitic acid via an acylation/deacylation cycle and that this profile changes during development.
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Affiliation(s)
- S U Tetzloff
- Department of Cell Biology and Physiology, University of New Mexico School of Medicine, Albuquerque, New Mexico 87131-5218, USA
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Baulieu EE, Schumacher M, Koenig H, Jung-Testas I, Akwa Y. Progesterone as a neurosteroid: actions within the nervous system. Cell Mol Neurobiol 1996; 16:143-54. [PMID: 8743966 DOI: 10.1007/bf02088173] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023]
Abstract
1. Some progesterone is synthesized within both the central and the peripheral nervous systems, where it regulates neurotransmission and important glial functions, such as the formation of myelin. Progesterone can thus be designated a "neurosteroid." 2. Steroids act not only on the brain, but also on peripheral nerves, which offer many advantages to study the biological significance of locally produced neurosteroids: their remarkable plasticity and regenerative capacity and their relatively simple structure. 3. By using the regenerating mouse sciatic nerve as a model, we have shown that progesterone synthesized by rat Schwann cells promotes the formation of new myelin sheaths. Progesterone also increases the number of myelinated axons when added at a low concentration to cocultures of Schwann cells and sensory neurons. 4. These findings show a function on myelination for locally produced progesterone and suggest a new pharmacological approach of myelin repair.
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Koenig HL, Schumacher M, Ferzaz B, Thi AN, Ressouches A, Guennoun R, Jung-Testas I, Robel P, Akwa Y, Baulieu EE. Progesterone synthesis and myelin formation by Schwann cells. Science 1995; 268:1500-3. [PMID: 7770777 DOI: 10.1126/science.7770777] [Citation(s) in RCA: 351] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Progesterone is shown here to be produced from pregnenolone by Schwann cells in peripheral nerves. After cryolesion of the sciatic nerve in male mice, axons regenerate and become myelinated. Blocking either the local synthesis or the receptor-mediated action of progesterone impaired remyelination. Administration of progesterone or its precursor, pregnenolone, to the lesion site increased the extent of myelin sheath formation. Myelination of axons was also increased when progesterone was added to cultures of rat dorsal root ganglia. These observations indicate a role for locally produced progesterone in myelination, demonstrate that progesterone is not simply a sex steroid, and suggest a new therapeutic approach to promote myelin repair.
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Affiliation(s)
- H L Koenig
- Laboratoire Neurobiologie du Développement, Université Bordeaux I, Talence, France
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Bizzozero OA, Tetzloff SU, Bharadwaj M. Overview: protein palmitoylation in the nervous system: current views and unsolved problems. Neurochem Res 1994; 19:923-33. [PMID: 7800121 DOI: 10.1007/bf00968702] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
Palmitoylation refers to a dynamic post-translational modification of proteins involving the covalent attachment of long-chain fatty acids to the side chains of cysteine, threonine or serine residues. In recent years, palmitoylation has been identified as a widespread modification of both viral and cellular proteins. Because of its dynamic nature, protein palmitoylation, like phosphorylation, appears to have a crucial role in the functioning of the nervous system. Several important questions regarding the post-translational acylation of cysteine residues in proteins are briefly discussed: (a) What are the molecular mechanisms involved in dynamic acylation? (b) What are the determinants of the fatty acid specificity and the structural requirements of the acceptor proteins? (c) What are the physiological signals regulating this type of protein modification, and (d) What is the biological role(s) of this reaction with respect to the functioning of specific nervous system proteins? We also present the current experimental obstacles that have to be overcome to fully understand the biology of this dynamic modification.
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Affiliation(s)
- O A Bizzozero
- Department of Biochemistry, University of New Mexico School of Medicine, Albuquerque 87131-5221
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Newman CM, Magee AI. Posttranslational processing of the ras superfamily of small GTP-binding proteins. BIOCHIMICA ET BIOPHYSICA ACTA 1993; 1155:79-96. [PMID: 8504132 DOI: 10.1016/0304-419x(93)90023-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Affiliation(s)
- C M Newman
- Laboratory of Eukaryotic Molecular Genetics, National Institute for Medical Research, Mill Hill, London, UK
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Abstract
Multiple sclerosis (MS) is characterized by the active degradation of central nervous system myelin, a multilamellar membrane system that insulates nerve axons. MS arises from complex interactions between genetic, immunological, infective, and biochemical mechanisms. Although the circumstances of MS etiology remain hypothetical, one persistent theme involves immune system recognition of myelin-specific antigens derived from myelin basic protein, the most abundant extrinsic myelin membrane protein, and/or another equally suitable myelin protein or lipid. Knowledge of the biochemical and physical-chemical properties of myelin proteins, and lipids, particularly their composition, organization, structure, and accessibility with respect to the compacted myelin multilayers, thus becomes central to understanding how and why these antigens become selected during the development of MS. This article focuses on the current understanding of the molecular basis of MS as it may relate to the protein and lipid components of myelin, which dictate myelin morphology on the basis of protein-lipid and lipid-lipid interactions, and the relationship, if any, between the protein/lipid components and the destruction of myelin in pathological situations.
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Affiliation(s)
- K A Williams
- Research Institute, Hospital for Sick Children, Toronto, Ontario, Canada
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Tuohy VK, Sobel RA, Lu Z, Laursen RA, Lees MB. Myelin proteolipid protein: minimum sequence requirements for active induction of autoimmune encephalomyelitis in SWR/J and SJL/J mice. J Neuroimmunol 1992; 39:67-74. [PMID: 1377711 DOI: 10.1016/0165-5728(92)90175-k] [Citation(s) in RCA: 44] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Proteolipid protein (PLP) is the major protein constituent of mammalian central nervous system myelin. We have previously identified two different PLP encephalitogenic T cell epitopes in two mouse strains. Murine PLP peptides 103-116 YKTTICGKGLSATV and 139-151 HCLGKWLGHPDKF are encephalitogenic determinants in SWR/J (H-2q) and SJL/J (H-2s) mice, respectively. The purpose of the present study was to determine the minimum sequence requirements for each of these PLP encephalitogens. In SWR/J mice, at least two distinct overlapping peptides can induce experimental autoimmune encephalomyelitis (EAE). The eleven residue sequences PLP 105-115 TTICGKGLSAT and PLP 106-116 TICGKGLSATV are encephalitogenic in SWR/J mice, but PLP 106-115 TICGKGLSAT, the decapeptide indigenous to both sequences, is non-encephalitogenic. In contrast, the shortest PLP sequence capable of inducing EAE in SJL/J mice is the nonapeptide 141-149 LGKWLGHPD. These data indicate that encephalitogenic determinants of PLP are short contiguous peptide sequences similar in length and diversity to those of MBP.
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Affiliation(s)
- V K Tuohy
- Department of Biochemistry, E.K. Shriver Center, Waltham, MA
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Bizzozero O, Leyba J, Nuñez D. Characterization of proteolipid protein fatty acylesterase from rat brain myelin. J Biol Chem 1992. [DOI: 10.1016/s0021-9258(18)42596-3] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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