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Hong J, Garfolo R, Kabre S, Humml C, Velanac V, Roué C, Beck B, Jeanette H, Haslam S, Bach M, Arora S, Acheta J, Nave KA, Schwab MH, Jourd’heuil D, Poitelon Y, Belin S. PMP2 regulates myelin thickening and ATP production during remyelination. Glia 2024; 72:885-898. [PMID: 38311982 PMCID: PMC11027087 DOI: 10.1002/glia.24508] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Revised: 12/22/2023] [Accepted: 01/16/2024] [Indexed: 02/06/2024]
Abstract
It is well established that axonal Neuregulin 1 type 3 (NRG1t3) regulates developmental myelin formation as well as EGR2-dependent gene activation and lipid synthesis. However, in peripheral neuropathy disease context, elevated axonal NRG1t3 improves remyelination and myelin sheath thickness without increasing Egr2 expression or activity, and without affecting the transcriptional activity of canonical myelination genes. Surprisingly, Pmp2, encoding for a myelin fatty acid binding protein, is the only gene whose expression increases in Schwann cells following overexpression of axonal NRG1t3. Here, we demonstrate PMP2 expression is directly regulated by NRG1t3 active form, following proteolytic cleavage. Then, using a transgenic mouse model overexpressing axonal NRG1t3 (NRG1t3OE) and knocked out for PMP2, we demonstrate that PMP2 is required for NRG1t3-mediated remyelination. We demonstrate that the sustained expression of Pmp2 in NRG1t3OE mice enhances the fatty acid uptake in sciatic nerve fibers and the mitochondrial ATP production in Schwann cells. In sum, our findings demonstrate that PMP2 is a direct downstream mediator of NRG1t3 and that the modulation of PMP2 downstream NRG1t3 activation has distinct effects on Schwann cell function during developmental myelination and remyelination.
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Affiliation(s)
- Jiayue Hong
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Rebekah Garfolo
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Sejal Kabre
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Christian Humml
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Viktorija Velanac
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Clémence Roué
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Brianna Beck
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Haley Jeanette
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Sarah Haslam
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Martin Bach
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Simar Arora
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Jenica Acheta
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
| | - Markus H. Schwab
- Department of Neurogenetics, Max Planck Institute for Multidisciplinary Sciences, Göttingen, Germany
- Paul Flechsig Institute of Neuropathology, University Hospital Leipzig, Leipzig, Germany
| | - David Jourd’heuil
- Department of Molecular and Cellular Physiology, Albany Medical College, Albany, New York, USA
| | - Yannick Poitelon
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
| | - Sophie Belin
- Department of Neuroscience and Experimental Therapeutics, Albany Medical College, Albany, New York, USA
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An K, Guo P, Zhang H, Zhu W, Cao W, Shi J, Wang S. Decreased Plasma Level of Lipoprotein Lipase Predicted Verbal Disfluency in Chinese Type 2 Diabetes Mellitus Patients with Early Cognitive Deficits. Curr Alzheimer Res 2021; 18:656-666. [PMID: 34551696 DOI: 10.2174/1567205018666210922105850] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2021] [Revised: 08/06/2021] [Accepted: 08/18/2021] [Indexed: 11/22/2022]
Abstract
BACKGROUND Lipoprotein Lipase (LPL) is the rate-limiting enzyme catalyzing the hydrolysis of triglycerides and contributes to the amyloid-β formation, which shows promise as a pathological factor of cognitive decline in Type 2 Diabetes Mellitus (T2DM). This study aimed to investigate the pathogenetic roles of LPL and rs328 polymorphism in Mild Cognitive Impairment (MCI) in patients with T2DM. METHODS Chinese patients with T2DM were recruited and divided into two groups based on the Montreal Cognitive Assessment score. Demographic data were collected, LPL was measured and neuropsychological test results were examined. RESULTS Seventy-nine patients with diabetes and MCI had significantly decreased plasma LPL levels (p = 0.007) when compared with health-cognition controls (n = 91). Correlation analysis revealed that LPL was positively correlated with clock drawing test (r = 0.158, p = 0.043) and logical memory test (r = 0.162, p = 0.037), while lipoprotein a (r = -0.214, p = 0.006) was inversely associated with LPL. Logistic regression analysis further demonstrated that LPL concentration was an independent factor for diabetic MCI (p = 0.036). No significant differences were observed in the distributions of rs328 variants between patients with MCI and the controls. Moreover, no remarkable association was found among plasma LPL levels, cognitive performances, and lipid levels between the genotypic subgroups. The trail making test A was increased in the GC group when compared with the CC genotype in the control group. CONCLUSION Decreased plasma level of LPL could probably predict early cognitive deficits, especially verbal disfluency.
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Affiliation(s)
- Ke An
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, No. 87 Ding Jia Qiao Road, Nanjing, 210009, China
| | - Peng Guo
- Changlu Street Community Health Service Center, No. 68 Bai Yu Road, Nanjing, 211512, China
| | - Haoqiang Zhang
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, No. 87 Ding Jia Qiao Road, Nanjing, 210009, China
| | - Wenwen Zhu
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, No. 87 Ding Jia Qiao Road, Nanjing, 210009, China
| | - Wuyou Cao
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, No. 87 Ding Jia Qiao Road, Nanjing, 210009, China
| | - Jijing Shi
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, No. 87 Ding Jia Qiao Road, Nanjing, 210009, China
| | - Shaohua Wang
- Department of Endocrinology, Affiliated Zhongda Hospital of Southeast University, No. 87 Ding Jia Qiao Road, Nanjing, 210009, China
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Poitelon Y, Kopec AM, Belin S. Myelin Fat Facts: An Overview of Lipids and Fatty Acid Metabolism. Cells 2020; 9:cells9040812. [PMID: 32230947 PMCID: PMC7226731 DOI: 10.3390/cells9040812] [Citation(s) in RCA: 141] [Impact Index Per Article: 35.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Revised: 03/24/2020] [Accepted: 03/25/2020] [Indexed: 12/11/2022] Open
Abstract
Myelin is critical for the proper function of the nervous system and one of the most complex cell–cell interactions of the body. Myelination allows for the rapid conduction of action potentials along axonal fibers and provides physical and trophic support to neurons. Myelin contains a high content of lipids, and the formation of the myelin sheath requires high levels of fatty acid and lipid synthesis, together with uptake of extracellular fatty acids. Recent studies have further advanced our understanding of the metabolism and functions of myelin fatty acids and lipids. In this review, we present an overview of the basic biology of myelin lipids and recent insights on the regulation of fatty acid metabolism and functions in myelinating cells. In addition, this review may serve to provide a foundation for future research characterizing the role of fatty acids and lipids in myelin biology and metabolic disorders affecting the central and peripheral nervous system.
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4
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Waegaert R, Dirrig-Grosch S, Parisot F, Keime C, Henriques A, Loeffler JP, René F. Longitudinal transcriptomic analysis of altered pathways in a CHMP2B intron5-based model of ALS-FTD. Neurobiol Dis 2019; 136:104710. [PMID: 31837425 DOI: 10.1016/j.nbd.2019.104710] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Revised: 10/28/2019] [Accepted: 12/08/2019] [Indexed: 12/12/2022] Open
Abstract
Amyotrophic lateral sclerosis and frontotemporal dementia are two neurodegenerative diseases with currently no cure. These two diseases share a clinical continuum with overlapping genetic causes. Mutations in the CHMP2B gene are found in patients with ALS, FTD and ALS-FTD. To highlight deregulated mechanisms occurring in ALS-FTD linked to the CHMP2B gene, we performed a whole transcriptomic study on lumbar spinal cord from CHMP2Bintron5 mice, a model that develops progressive motor alterations associated with dementia symptoms reminiscent of both ALS and FTD. To gain insight into the transcriptomic changes taking place during disease progression this study was performed at three stages: asymptomatic, symptomatic and end stage. We showed that before appearance of motor symptoms, the major disrupted mechanisms were linked with the immune system/inflammatory response and lipid metabolism. These processes were progressively replaced by alterations of neuronal electric activity as motor symptoms appeared, alterations that could lead to motor neuron dysfunction. To investigate overlapping alterations in gene expression between two ALS-causing genes, we then compared the transcriptome of symptomatic CHMP2Bintron5 mice with the one of symptomatic SOD1G86R mice and found the same families deregulated providing further insights into common underlying dysfunction of biological pathways, disrupted or disturbed in ALS. Altogether, this study provides a database to explore potential new candidate genes involved in the CHMP2Bintron5-based pathogenesis of ALS, and provides molecular clues to further understand the functional consequences that diseased neurons expressing CHMP2B mutant may have on their neighbor cells.
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Affiliation(s)
- Robin Waegaert
- INSERM U1118 Mécanismes centraux et périphériques de la neurodégénérescence, Université de Strasbourg, 11 rue Humann, Strasbourg, France
| | - Sylvie Dirrig-Grosch
- INSERM U1118 Mécanismes centraux et périphériques de la neurodégénérescence, Université de Strasbourg, 11 rue Humann, Strasbourg, France
| | - Florian Parisot
- INSERM U1118 Mécanismes centraux et périphériques de la neurodégénérescence, Université de Strasbourg, 11 rue Humann, Strasbourg, France
| | - Céline Keime
- Institut de Génétique et de Biologie Moléculaire et Cellulaire, INSERM U1258, CNRS, UMR7104, Université de Strasbourg, 1 Rue Laurent Fries, 67400 Illkirch-Graffenstaden, France
| | - Alexandre Henriques
- INSERM U1118 Mécanismes centraux et périphériques de la neurodégénérescence, Université de Strasbourg, 11 rue Humann, Strasbourg, France
| | - Jean-Philippe Loeffler
- INSERM U1118 Mécanismes centraux et périphériques de la neurodégénérescence, Université de Strasbourg, 11 rue Humann, Strasbourg, France
| | - Frédérique René
- INSERM U1118 Mécanismes centraux et périphériques de la neurodégénérescence, Université de Strasbourg, 11 rue Humann, Strasbourg, France.
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Singh D, Harding AJ, Albadawi E, Boissonade FM, Haycock JW, Claeyssens F. Additive manufactured biodegradable poly(glycerol sebacate methacrylate) nerve guidance conduits. Acta Biomater 2018; 78:48-63. [PMID: 30075322 DOI: 10.1016/j.actbio.2018.07.055] [Citation(s) in RCA: 64] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 07/09/2018] [Accepted: 07/30/2018] [Indexed: 12/12/2022]
Abstract
Entubulating devices to repair peripheral nerve injuries are limited in their effectiveness particularly for critical gap injuries. Current clinically used nerve guidance conduits are often simple tubes, far stiffer than that of the native tissue. This study assesses the use of poly(glycerol sebacate methacrylate) (PGSm), a photocurable formulation of the soft biodegradable material, PGS, for peripheral nerve repair. The material was synthesized, the degradation rate and mechanical properties of material were assessed and nerve guidance conduits were structured via stereolithography. In vitro cell studies confirmed PGSm as a supporting substrate for both neuronal and glial cell growth. Ex vivo studies highlight the ability of the cells from a dissociated dorsal root ganglion to grow out and align along the internal topographical grooves of printed nerve guide conduits. In vivo results in a mouse common fibular nerve injury model show regeneration of axons through the PGSm conduit into the distal stump after 21 days. After conduit repair levels of spinal cord glial activation (an indicator for neuropathic pain development) were equivalent to those seen following graft repair. In conclusion, results indicate that PGSm can be structured via additive manufacturing into functional NGCs. This study opens the route of personalized conduit manufacture for nerve injury repair. STATEMENT OF SIGNIFICANCE This study describes the use of photocurable of Poly(Glycerol Sebacate) (PGS) for light-based additive manufacturing of Nerve Guidance Conduits (NGCs). PGS is a promising flexible biomaterial for soft tissue engineering, and in particular for nerve repair. Its mechanical properties and degradation rate are within the desirable range for use in neuronal applications. The nerve regeneration supported by the PGS NGCs is similar to an autologous nerve transplant, the current gold standard. A second assessment of regeneration is the activation of glial cells within the spinal cord of the tested animals which reveals no significant increase in neuropathic pain by using the NGCs. This study highlights the successful use of a biodegradable additive manufactured NGC for peripheral nerve repair.
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Affiliation(s)
- Dharaminder Singh
- Department of Materials Science and Engineering, Broad Lane, Sheffield S3 7HQ, United Kingdom
| | - Adam J Harding
- School of Clinical Dentistry, Claremont Crescent, Sheffield S10 2TN, United Kingdom
| | - Emad Albadawi
- School of Clinical Dentistry, Claremont Crescent, Sheffield S10 2TN, United Kingdom; Department of Anatomy, Faculty of Medicine, Taibah University, Almadinah Almunawarah, Kingdom of Saudi Arabia
| | - Fiona M Boissonade
- School of Clinical Dentistry, Claremont Crescent, Sheffield S10 2TN, United Kingdom.
| | - John W Haycock
- Department of Materials Science and Engineering, Broad Lane, Sheffield S3 7HQ, United Kingdom.
| | - Frederik Claeyssens
- Department of Materials Science and Engineering, Broad Lane, Sheffield S3 7HQ, United Kingdom.
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Fledrich R, Abdelaal T, Rasch L, Bansal V, Schütza V, Brügger B, Lüchtenborg C, Prukop T, Stenzel J, Rahman RU, Hermes D, Ewers D, Möbius W, Ruhwedel T, Katona I, Weis J, Klein D, Martini R, Brück W, Müller WC, Bonn S, Bechmann I, Nave KA, Stassart RM, Sereda MW. Targeting myelin lipid metabolism as a potential therapeutic strategy in a model of CMT1A neuropathy. Nat Commun 2018; 9:3025. [PMID: 30072689 PMCID: PMC6072747 DOI: 10.1038/s41467-018-05420-0] [Citation(s) in RCA: 50] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2017] [Accepted: 06/28/2018] [Indexed: 01/17/2023] Open
Abstract
In patients with Charcot-Marie-Tooth disease 1A (CMT1A), peripheral nerves display aberrant myelination during postnatal development, followed by slowly progressive demyelination and axonal loss during adult life. Here, we show that myelinating Schwann cells in a rat model of CMT1A exhibit a developmental defect that includes reduced transcription of genes required for myelin lipid biosynthesis. Consequently, lipid incorporation into myelin is reduced, leading to an overall distorted stoichiometry of myelin proteins and lipids with ultrastructural changes of the myelin sheath. Substitution of phosphatidylcholine and phosphatidylethanolamine in the diet is sufficient to overcome the myelination deficit of affected Schwann cells in vivo. This treatment rescues the number of myelinated axons in the peripheral nerves of the CMT rats and leads to a marked amelioration of neuropathic symptoms. We propose that lipid supplementation is an easily translatable potential therapeutic approach in CMT1A and possibly other dysmyelinating neuropathies.
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Affiliation(s)
- R Fledrich
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, 37075, Germany.
- Institute of Anatomy, University of Leipzig, Leipzig, 04103, Germany.
- Department of Neuropathology, University Hospital Leipzig, Leipzig, 04103, Germany.
| | - T Abdelaal
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, 37075, Germany
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, 37075, Germany
- Chemistry of Natural and Microbial Products Department, Pharmaceutical and Drug Industries Division, National Research Centre, Giza, 12622, Egypt
| | - L Rasch
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, 37075, Germany
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, 37075, Germany
| | - V Bansal
- Center for Molecular Neurobiology, Institute of Medical Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, 20251, Germany
| | - V Schütza
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, 37075, Germany
- Department of Neuropathology, University Hospital Leipzig, Leipzig, 04103, Germany
| | - B Brügger
- Heidelberg University Biochemistry Center (BZH), Heidelberg, 69120, Germany
| | - C Lüchtenborg
- Heidelberg University Biochemistry Center (BZH), Heidelberg, 69120, Germany
| | - T Prukop
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, 37075, Germany
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, 37075, Germany
- Institute of Clinical Pharmacology, University Medical Center Göttingen, Göttingen, 37075, Germany
| | - J Stenzel
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, 37075, Germany
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, 37075, Germany
| | - R U Rahman
- Center for Molecular Neurobiology, Institute of Medical Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, 20251, Germany
| | - D Hermes
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, 37075, Germany
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, 37075, Germany
| | - D Ewers
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, 37075, Germany
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, 37075, Germany
| | - W Möbius
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, 37075, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain (CNMPB), Göttingen, 37075, Germany
| | - T Ruhwedel
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, 37075, Germany
| | - I Katona
- Institute of Neuropathology, University Hospital Aachen, Aachen, 52074, Germany
| | - J Weis
- Institute of Neuropathology, University Hospital Aachen, Aachen, 52074, Germany
| | - D Klein
- Department of Neurology, Section of Developmental Neurobiology, University Hospital Wuerzburg, Wuerzburg, 97080, Germany
| | - R Martini
- Department of Neurology, Section of Developmental Neurobiology, University Hospital Wuerzburg, Wuerzburg, 97080, Germany
| | - W Brück
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, 37075, Germany
| | - W C Müller
- Department of Neuropathology, University Hospital Leipzig, Leipzig, 04103, Germany
| | - S Bonn
- Center for Molecular Neurobiology, Institute of Medical Systems Biology, University Medical Center Hamburg-Eppendorf, Hamburg, 20251, Germany
- German Center for Neurodegenerative Diseases, Tübingen, 72076, Germany
| | - I Bechmann
- Institute of Anatomy, University of Leipzig, Leipzig, 04103, Germany
| | - K A Nave
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, 37075, Germany.
| | - R M Stassart
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, 37075, Germany.
- Department of Neuropathology, University Hospital Leipzig, Leipzig, 04103, Germany.
- Institute of Neuropathology, University Medical Center Göttingen, Göttingen, 37075, Germany.
| | - M W Sereda
- Department of Neurogenetics, Max-Planck-Institute of Experimental Medicine, Göttingen, 37075, Germany.
- Department of Clinical Neurophysiology, University Medical Center Göttingen, Göttingen, 37075, Germany.
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Rachana KS, Manu MS, Advirao GM. Insulin-induced upregulation of lipoprotein lipase in Schwann cells during diabetic peripheral neuropathy. Diabetes Metab Syndr 2018; 12:525-530. [PMID: 29602762 DOI: 10.1016/j.dsx.2018.03.017] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2018] [Accepted: 03/16/2018] [Indexed: 01/03/2023]
Abstract
Diabetic peripheral neuropathy (DPN) is one of the major complications associated with diabetes. It is characterized by the degeneration of the myelin sheath around axons, referred to as demyelination. Such demyelinations are often caused by reduced lipid component of the myelin sheath. Since, lipoprotein lipase (LPL) provides the lipid for myelin sheath by hydrolysing the triglyceride rich lipoproteins, and also helps in the uptake of lipids by the Schwann cells (SCs) for its utilization, LPL is considered as the important factor in the regeneration of myelin sheath during diabetic neuropathy. Earlier reports from our laboratory have provided the insights of insulin and its receptor in SCs during diabetic neuropathy. In order to evaluate the long term effect of insulin on lipid metabolism during diabetic neuropathy, in this study, we analyzed the expression of LPL in SCs under normal, high glucose and insulin treated conditions. A decrease in the expression of LPL was observed in SCs of high glucose condition and it was reversed upon insulin treatment. Histochemical observations of sciatic nerve of insulin treated neuropathy subjects showed the improved nerve morphology, signifying the importance of insulin in restoring the pathophysiology of diabetic neuropathy.
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Affiliation(s)
| | - Mallahalli S Manu
- Department of Biochemistry, Davangere University, Davangere, Karnataka, India
| | - Gopal M Advirao
- Department of Biochemistry, Davangere University, Davangere, Karnataka, India.
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8
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Gao Y, Layritz C, Legutko B, Eichmann TO, Laperrousaz E, Moullé VS, Cruciani-Guglielmacci C, Magnan C, Luquet S, Woods SC, Eckel RH, Yi CX, Garcia-Caceres C, Tschöp MH. Disruption of Lipid Uptake in Astroglia Exacerbates Diet-Induced Obesity. Diabetes 2017; 66:2555-2563. [PMID: 28710138 PMCID: PMC6463752 DOI: 10.2337/db16-1278] [Citation(s) in RCA: 51] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Accepted: 07/04/2017] [Indexed: 02/06/2023]
Abstract
Neuronal circuits in the brain help to control feeding behavior and systemic metabolism in response to afferent nutrient and hormonal signals. Although astrocytes have historically been assumed to have little relevance for such neuroendocrine control, we investigated whether lipid uptake via lipoprotein lipase (LPL) in astrocytes is required to centrally regulate energy homeostasis. Ex vivo studies with hypothalamus-derived astrocytes showed that LPL expression is upregulated by oleic acid, whereas it is decreased in response to palmitic acid or triglycerides. Likewise, astrocytic LPL deletion reduced the accumulation of lipid droplets in those glial cells. Consecutive in vivo studies showed that postnatal ablation of LPL in glial fibrillary acidic protein-expressing astrocytes induced exaggerated body weight gain and glucose intolerance in mice exposed to a high-fat diet. Intriguingly, astrocytic LPL deficiency also triggered increased ceramide content in the hypothalamus, which may contribute to hypothalamic insulin resistance. We conclude that hypothalamic LPL functions in astrocytes to ensure appropriately balanced nutrient sensing, ceramide distribution, body weight regulation, and glucose metabolism.
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Affiliation(s)
- Yuanqing Gao
- Helmholtz Diabetes Center (HDC) and German Center for Diabetes Research (DZD), Helmholtz Zentrum München and Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Clarita Layritz
- Helmholtz Diabetes Center (HDC) and German Center for Diabetes Research (DZD), Helmholtz Zentrum München and Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
| | - Beata Legutko
- Helmholtz Diabetes Center (HDC) and German Center for Diabetes Research (DZD), Helmholtz Zentrum München and Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
| | - Thomas O Eichmann
- Institute of Molecular Biosciences, University of Graz, Graz, Austria
| | - Elise Laperrousaz
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, University of Paris Diderot, Paris, France
| | - Valentine S Moullé
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, University of Paris Diderot, Paris, France
| | - Celine Cruciani-Guglielmacci
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, University of Paris Diderot, Paris, France
| | - Christophe Magnan
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, University of Paris Diderot, Paris, France
| | - Serge Luquet
- Unité de Biologie Fonctionnelle et Adaptative, Sorbonne Paris Cité, CNRS UMR 8251, University of Paris Diderot, Paris, France
| | - Stephen C Woods
- Department of Psychiatry and Behavioral Neuroscience, University of Cincinnati, Cincinnati, OH
| | - Robert H Eckel
- Division of Endocrinology, Metabolism, & Diabetes, University of Colorado at Denver, Denver, CO
| | - Chun-Xia Yi
- Helmholtz Diabetes Center (HDC) and German Center for Diabetes Research (DZD), Helmholtz Zentrum München and Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
- Department of Endocrinology and Metabolism, Academic Medical Center, University of Amsterdam, Amsterdam, the Netherlands
| | - Cristina Garcia-Caceres
- Helmholtz Diabetes Center (HDC) and German Center for Diabetes Research (DZD), Helmholtz Zentrum München and Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
| | - Matthias H Tschöp
- Helmholtz Diabetes Center (HDC) and German Center for Diabetes Research (DZD), Helmholtz Zentrum München and Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
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9
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Libby AE, Wang H, Mittal R, Sungelo M, Potma E, Eckel RH. Lipoprotein lipase is an important modulator of lipid uptake and storage in hypothalamic neurons. Biochem Biophys Res Commun 2015; 465:287-92. [PMID: 26265042 DOI: 10.1016/j.bbrc.2015.08.026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 08/06/2015] [Indexed: 11/28/2022]
Abstract
LPL is the rate-limiting enzyme for uptake of TG-derived FFA in peripheral tissues, and the enzyme is expressed in the brain and CNS. We previously created a mouse which lacks neuronal LPL. This animal becomes obese on a standard chow, and we observed reduced lipid uptake in the hypothalamus at 3 months preceding obesity. In our present study, we replicated the animal phenotype in an immortalized mouse hypothalamic cell line (N41) to examine how LPL affects expression of AgRP as well as entry and storage of lipids into neurons. We show that LPL is able to modulate levels of the orexigenic peptide AgRP. LPL also exerts effects on lipid uptake into culture neurons, and that uptake of neutral lipid can be enhanced even by mutant LPL lacking catalytic activity. N41 cells also accumulate neutral lipid in droplets, and this is at least in part regulated by LPL. These data in addition to those published in mice with neuron-specific deletion of LPL suggest that neuronal LPL is an important regulator of lipid homeostasis in neurons and that alterations in LPL levels may have important effects on systemic metabolism and neuronal lipid biology.
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Affiliation(s)
- Andrew E Libby
- Division of Endocrinology, Metabolism, & Diabetes, University of Colorado at Denver, USA.
| | - Hong Wang
- Division of Endocrinology, Metabolism, & Diabetes, University of Colorado at Denver, USA
| | - Richa Mittal
- Beckman Laser Institute, University of California, Irvine, USA
| | - Mitchell Sungelo
- Division of Endocrinology, Metabolism, & Diabetes, University of Colorado at Denver, USA
| | - Eric Potma
- Beckman Laser Institute, University of California, Irvine, USA
| | - Robert H Eckel
- Division of Endocrinology, Metabolism, & Diabetes, University of Colorado at Denver, USA
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10
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Gong H, Dong W, Rostad SW, Marcovina SM, Albers JJ, Brunzell JD, Vuletic S. Lipoprotein lipase (LPL) is associated with neurite pathology and its levels are markedly reduced in the dentate gyrus of Alzheimer's disease brains. J Histochem Cytochem 2013; 61:857-68. [PMID: 24004859 PMCID: PMC3840745 DOI: 10.1369/0022155413505601] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022] Open
Abstract
Lipoprotein lipase (LPL) is involved in regulation of fatty acid metabolism, and facilitates cellular uptake of lipoproteins, lipids and lipid-soluble vitamins. We evaluated LPL distribution in healthy and Alzheimer’s disease (AD) brain tissue and its relative levels in cerebrospinal fluid. LPL immunostaining is widely present in different neuronal subgroups, microglia, astrocytes and oligodendroglia throughout cerebrum, cerebellum and spinal cord. LPL immunoreactivity is also present in leptomeninges, small blood vessels, choroid plexus and ependymal cells, Schwann cells associated with cranial nerves, and in anterior and posterior pituitary. In vitro studies have shown presence of secreted LPL in conditioned media of human cortical neuronal cell line (HCN2) and neuroblastoma cells (SK-N-SH), but not in media of cultured primary human astrocytes. LPL was present in cytoplasmic and nuclear fractions of neuronal cells and astrocytes in vitro. LPL immunoreactivity strongly associates with AD-related pathology, staining diffuse plaques, dystrophic and swollen neurites, possible Hirano bodies and activated glial cells. We observed no staining associated with neurofibrillary tangles or granulovacuolar degeneration. Granule cells of the dentate gyrus and the associated synaptic network showed significantly reduced staining in AD compared to control tissue. LPL was also reduced in AD CSF samples relative to those in controls.
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Affiliation(s)
- Huilin Gong
- Northwest Lipid Metabolism and Diabetes Research Laboratories, Department of Medicine, School of Medicine, University of Washington, Seattle, WA (HG, WD, SMM, JJA, SV)
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11
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Chen K, Deng S, Lu H, Zheng Y, Yang G, Kim D, Cao Q, Wu JQ. RNA-seq characterization of spinal cord injury transcriptome in acute/subacute phases: a resource for understanding the pathology at the systems level. PLoS One 2013; 8:e72567. [PMID: 23951329 PMCID: PMC3739761 DOI: 10.1371/journal.pone.0072567] [Citation(s) in RCA: 62] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2013] [Accepted: 07/13/2013] [Indexed: 12/29/2022] Open
Abstract
Spinal cord injury (SCI) is a devastating neurological disease without effective treatment. To generate a comprehensive view of the mechanisms involved in SCI pathology, we applied RNA-Sequencing (RNA-Seq) technology to characterize the temporal changes in global gene expression after contusive SCI in mice. We sequenced tissue samples from acute and subacute phases (2 days and 7 days after injury) and systematically characterized the transcriptomes with the goal of identifying pathways and genes critical in SCI pathology. The top enriched functional categories include “inflammation response,” “neurological disease,” “cell death and survival” and “nervous system development.” The top enriched pathways include LXR/RXR Activation and Atherosclerosis Signaling, etc. Furthermore, we developed a systems-based analysis framework in order to identify key determinants in the global gene networks of the acute and sub-acute phases. Some candidate genes that we identified have been shown to play important roles in SCI, which demonstrates the validity of our approach. There are also many genes whose functions in SCI have not been well studied and can be further investigated by future experiments. We have also incorporated pharmacogenomic information into our analyses. Among the genes identified, the ones with existing drug information can be readily tested in SCI animal models. Therefore, in this study we have described an example of how global gene profiling can be translated to identifying genes of interest for functional tests in the future and generating new hypotheses. Additionally, the RNA-Seq enables splicing isoform identification and the estimation of expression levels, thus providing useful information for increasing the specificity of drug design and reducing potential side effect. In summary, these results provide a valuable reference data resource for a better understanding of the SCI process in the acute and sub-acute phases.
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Affiliation(s)
- Kenian Chen
- The Vivian L. Smith Department of Neurosurgery, University of Texas Medical School at Houston, Houston, Texas, United States of America
- Center for Stem Cell and Regenerative Medicine, UT Brown Institution of Molecular Medicine, Houston, Texas, United States of America
| | - Shuyun Deng
- The Vivian L. Smith Department of Neurosurgery, University of Texas Medical School at Houston, Houston, Texas, United States of America
- Center for Stem Cell and Regenerative Medicine, UT Brown Institution of Molecular Medicine, Houston, Texas, United States of America
| | - Hezuo Lu
- The Vivian L. Smith Department of Neurosurgery, University of Texas Medical School at Houston, Houston, Texas, United States of America
- Center for Stem Cell and Regenerative Medicine, UT Brown Institution of Molecular Medicine, Houston, Texas, United States of America
| | - Yiyan Zheng
- The Vivian L. Smith Department of Neurosurgery, University of Texas Medical School at Houston, Houston, Texas, United States of America
- Center for Stem Cell and Regenerative Medicine, UT Brown Institution of Molecular Medicine, Houston, Texas, United States of America
| | - Guodong Yang
- The Vivian L. Smith Department of Neurosurgery, University of Texas Medical School at Houston, Houston, Texas, United States of America
- Center for Stem Cell and Regenerative Medicine, UT Brown Institution of Molecular Medicine, Houston, Texas, United States of America
| | - Dong Kim
- The Vivian L. Smith Department of Neurosurgery, University of Texas Medical School at Houston, Houston, Texas, United States of America
- Center for Stem Cell and Regenerative Medicine, UT Brown Institution of Molecular Medicine, Houston, Texas, United States of America
| | - Qilin Cao
- The Vivian L. Smith Department of Neurosurgery, University of Texas Medical School at Houston, Houston, Texas, United States of America
- Center for Stem Cell and Regenerative Medicine, UT Brown Institution of Molecular Medicine, Houston, Texas, United States of America
- * E-mail: ; (JQW) (QC)
| | - Jia Qian Wu
- The Vivian L. Smith Department of Neurosurgery, University of Texas Medical School at Houston, Houston, Texas, United States of America
- Center for Stem Cell and Regenerative Medicine, UT Brown Institution of Molecular Medicine, Houston, Texas, United States of America
- * E-mail: ; (JQW) (QC)
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12
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Abstract
Lipoprotein lipase (LPL) is rate limiting in the provision of triglyceride-rich lipoprotein-derived lipids into tissues. LPL is also present in the brain, where its function has remained elusive. Recent evidence implicates a role of LPL in the brain in two processes: (a) the regulation of energy balance and body weight and (b) cognition. Mice with neuron-specific deletion of LPL have increases in food intake that lead to obesity, and then reductions in energy expenditure that further contribute to and sustain the phenotype. In other mice with LPL deficiency rescued from neonatal lethality by somatic gene transfer wherein LPL in the brain remains absent, altered cognition ensues. Taking into consideration data that associate LPL mutations with Alzheimer's disease, a role for LPL in learning and memory seems likely. Overall, the time is ripe for new insights into how LPL-mediated lipoprotein metabolism in the brain impacts CNS processes and systems biology.
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Affiliation(s)
- Hong Wang
- Division of Endocrinology, Metabolism and Diabetes, Department of Medicine, School of Medicine, University of Colorado Denver Anschutz Medical Campus, Aurora, CO 80045, USA.
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13
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King RHM, Chandler D, Lopaticki S, Huang D, Blake J, Muddle JR, Kilpatrick T, Nourallah M, Miyata T, Okuda T, Carter KW, Hunter M, Angelicheva D, Morahan G, Kalaydjieva L. Ndrg1 in development and maintenance of the myelin sheath. Neurobiol Dis 2011; 42:368-80. [PMID: 21303696 DOI: 10.1016/j.nbd.2011.01.030] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2010] [Revised: 01/13/2011] [Accepted: 01/28/2011] [Indexed: 02/04/2023] Open
Abstract
CMT4D disease is a severe autosomal recessive demyelinating neuropathy with extensive axonal loss leading to early disability, caused by mutations in the N-myc downstream regulated gene 1 (NDRG1). NDRG1 is expressed at particularly high levels in the Schwann cell (SC), but its physiological function(s) are unknown. To help with their understanding, we characterise the phenotype of a new mouse model, stretcher (str), with total Ndrg1 deficiency, in comparison with the hypomorphic Ndrg1 knock-out (KO) mouse. While both models display normal initial myelination and a transition to overt pathology between weeks 3 and 5, the markedly more severe str phenotype suggests that even low Ndrg1 expression results in significant phenotype rescue. Neither model replicates fully the features of CMT4D: although axon damage is present, regenerative capacity is unimpaired and the mice do not display the early severe axonal loss typical of the human disease. The widespread large fibre demyelination coincides precisely with the period of rapid growth of the animals and the dramatic (160-500-fold) increase in myelin volume and length in large fibres. This is followed by stabilisation after week 10, while small fibres remain unaffected. Gene expression profiling of str peripheral nerve reveals non-specific secondary changes at weeks 5 and 10 and preliminary data point to normal proteasomal function. Our findings do not support the proposed roles of NDRG1 in growth arrest, terminal differentiation, gene expression regulation and proteasomal degradation. Impaired SC trafficking failing to meet the considerable demands of nerve growth, emerges as the likely pathogenetic mechanism in NDRG1 deficiency.
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Affiliation(s)
- Rosalind H M King
- Department of Clinical Neurosciences, Institute of Neurology, UCL, London NW3 2PF, UK.
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14
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Wang X, Sun W, Xu E. The expression and activity of brain lipoprotein lipase is increased after acute cerebral ischemia-reperfusion in rats. Neuropathology 2009; 30:131-9. [PMID: 19780982 DOI: 10.1111/j.1440-1789.2009.01061.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Lipoprotein lipase (LPL) is a key enzyme involved in lipid metabolism. Previous studies have shown that the levels of brain LPL mRNA, protein and activity are up-regulated after brain and nerve injury. The aim of this study was to determine the response of expression and activity of brain LPL following acute cerebral ischemia-reperfusion. Adult male Sprague-Dawley rats were subjected to surgical occlusion of the middle cerebral artery. The expression of brain LPL was assessed by immunohistochemical staining and the enzyme activity of brain LPL was evaluated by colorimetric method. Increase of LPL immunopositive cells in the cerebral cortex around the infarction area was observed at 4, 6, 12 h ischemia, 2 h ischemia 2 h reperfusion, and 4 h ischemia 2 h reperfusion. LPL activity was significantly decreased in the ischemic side cortex at 2 h ischemia, and then significantly increased at 4 and 6 h ischemia. Our results showed that LPL immunopositive cells were increased in the cortex around the infarction area, and activity of LPL first decreased and then increased following acute cerebral ischemia-reperfusion. These results may suggest that LPL plays a potential role in the pathophysiological response of the brain to cerebral ischemia-reperfusion.
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Affiliation(s)
- Xiaojuan Wang
- Institute of Neurosciences, the 2nd Affiliated Hospital of Guangzhou Medical College, Key Laboratory of Neurogenetics and Channelopathies of Guangdong Province and the Ministry of Education of China, Guangzhou, China
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15
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Abstract
Lipoprotein lipase (LPL) is a multifunctional enzyme produced by many tissues, including adipose tissue, cardiac and skeletal muscle, islets, and macrophages. LPL is the rate-limiting enzyme for the hydrolysis of the triglyceride (TG) core of circulating TG-rich lipoproteins, chylomicrons, and very low-density lipoproteins (VLDL). LPL-catalyzed reaction products, fatty acids, and monoacylglycerol are in part taken up by the tissues locally and processed differentially; e.g., they are stored as neutral lipids in adipose tissue, oxidized, or stored in skeletal and cardiac muscle or as cholesteryl ester and TG in macrophages. LPL is regulated at transcriptional, posttranscriptional, and posttranslational levels in a tissue-specific manner. Nutrient states and hormonal levels all have divergent effects on the regulation of LPL, and a variety of proteins that interact with LPL to regulate its tissue-specific activity have also been identified. To examine this divergent regulation further, transgenic and knockout murine models of tissue-specific LPL expression have been developed. Mice with overexpression of LPL in skeletal muscle accumulate TG in muscle, develop insulin resistance, are protected from excessive weight gain, and increase their metabolic rate in the cold. Mice with LPL deletion in skeletal muscle have reduced TG accumulation and increased insulin action on glucose transport in muscle. Ultimately, this leads to increased lipid partitioning to other tissues, insulin resistance, and obesity. Mice with LPL deletion in the heart develop hypertriglyceridemia and cardiac dysfunction. The fact that the heart depends increasingly on glucose implies that free fatty acids are not a sufficient fuel for optimal cardiac function. Overall, LPL is a fascinating enzyme that contributes in a pronounced way to normal lipoprotein metabolism, tissue-specific substrate delivery and utilization, and the many aspects of obesity and other metabolic disorders that relate to energy balance, insulin action, and body weight regulation.
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Affiliation(s)
- Hong Wang
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Denver Anschutz Medical Campus, Aurora, Colorado 80045, USA
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16
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Transthyretin knockout mouse nerves have increased lipoprotein lipase and sphingolipid content following crush. Neurosci Lett 2008; 446:83-7. [DOI: 10.1016/j.neulet.2008.09.054] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2008] [Revised: 08/25/2008] [Accepted: 09/17/2008] [Indexed: 11/21/2022]
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17
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Sango K, Suzuki T, Yanagisawa H, Takaku S, Hirooka H, Tamura M, Watabe K. High glucose-induced activation of the polyol pathway and changes of gene expression profiles in immortalized adult mouse Schwann cells IMS32. J Neurochem 2006; 98:446-58. [PMID: 16805838 DOI: 10.1111/j.1471-4159.2006.03885.x] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/17/2023]
Abstract
We investigated the polyol pathway activity and the gene expression profiles in immortalized adult mouse Schwann cells (IMS32) under normal (5.6 mM) and high (30 and 56 mM) glucose conditions for 7-14 days in culture. Messenger RNA and the protein expression of aldose reductase (AR) and the intracellular sorbitol and fructose contents were up-regulated in IMS32 under high glucose conditions compared with normal glucose conditions. By employing DNA microarray and subsequent RT-PCR/northern blot analyses, we observed significant up-regulation of the mRNA expressions for serum amyloid A3 (SAA3), angiopoietin-like 4 (ANGPTL4) and ecotropic viral integration site 3 (Evi3), and the down-regulation of aldehyde reductase (AKR1A4) mRNA expression in the cells under high glucose (30 mM) conditions. The application of an AR inhibitor, SNK-860, to the high glucose medium ameliorated the increased sorbitol and fructose contents and the reduced AKR1A4 mRNA expression, while it had no effect on mRNA expressions for SAA3, ANGPTL4 or Evi3. Considering that the exposure to the high glucose (>or= 30 mM) conditions mimicking hyperglycaemia in vivo accelerated the polyol pathway in IMS32, but not in other previously reported Schwann cells, the culture system of IMS32 under those conditions may provide novel findings about the polyol pathway-related abnormalities in diabetic neuropathy.
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Affiliation(s)
- Kazunori Sango
- Department of Developmental Morphology, Tokyo Metropolitan Institute for Neuroscience, Fuchu, Tokyo, Japan.
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18
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Cheng H, Guan S, Han X. Abundance of triacylglycerols in ganglia and their depletion in diabetic mice: implications for the role of altered triacylglycerols in diabetic neuropathy. J Neurochem 2006; 97:1288-300. [PMID: 16539649 PMCID: PMC2137160 DOI: 10.1111/j.1471-4159.2006.03794.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
Herein, we report the first study on the mass distribution and molecular species composition of abundant triacylglycerols (TAG) in ganglia. This study demonstrates five novel findings. First, unanticipated high levels of TAG were present in all examined ganglia from multiple species (e.g. mouse, rat and rabbit). Second, ganglial TAG mass content is location-dependent. Third, the TAG mass levels in ganglia are species-specific. Fourth, dorsal root ganglial TAG mass levels in streptozotocin-induced diabetic mice are dramatically depleted relative to those found in untreated control mice. Fifth, mouse ganglial TAG mass levels decrease with age although molecular species composition is not changed. Collectively, these results indicate that TAG is an important component of ganglia and may potentially contribute to pathological alterations in peripheral neuronal function in diabetic neuropathy.
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MESH Headings
- Age Factors
- Aging/metabolism
- Animals
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Experimental/physiopathology
- Diabetic Neuropathies/etiology
- Diabetic Neuropathies/metabolism
- Diabetic Neuropathies/physiopathology
- Disease Models, Animal
- Female
- Ganglia, Spinal/metabolism
- Ganglia, Spinal/physiopathology
- Ganglia, Sympathetic/metabolism
- Ganglia, Sympathetic/physiopathology
- Male
- Mass Spectrometry
- Mice
- Mice, Inbred C57BL
- Nerve Degeneration/etiology
- Nerve Degeneration/metabolism
- Nerve Degeneration/physiopathology
- Neurons, Afferent/metabolism
- Rabbits
- Rats
- Rats, Sprague-Dawley
- Species Specificity
- Triglycerides/analysis
- Triglycerides/deficiency
- Triglycerides/metabolism
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Affiliation(s)
- Hua Cheng
- Division of Bioorganic Chemistry and Molecular Pharmacology, Washington University School of Medicine, St Louis, Missouri 63110, USA
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19
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Nunes AF, Saraiva MJ, Sousa MM. Transthyretin knockouts are a new mouse model for increased neuropeptide Y. FASEB J 2005; 20:166-8. [PMID: 16263939 DOI: 10.1096/fj.05-4106fje] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Transthyretin (TTR) has access to the brain and nerve through the blood and cerebrospinal fluid. To investigate TTR function in nervous system homeostasis, differential gene expression in wild-type (WT) and TTR knockout (KO) mice was assessed. Peptidylglycine alpha-amidating monooxygenase (PAM), the rate-limiting enzyme in neuropeptide maturation, is overexpressed in the peripheral (PNS) and central nervous system (CNS) of TTR KOs that, consequently, display increased neuropeptide Y (NPY) levels. NPY acts on energy homeostasis by increasing white adipose tissue lipoprotein lipase (LPL) and decreasing thermogenesis; accordingly, we show increased LPL expression and activity in white adipose tissue, PNS, and CNS as well as decreased body temperature in TTR KOs. Associated to increased NPY levels, TTR KOs display increased carbohydrate consumption and preference. In neuronal cells, absence of TTR is related to increased PAM activity, NPY levels and LPL expression, reinforcing that TTR is involved in neuropeptide maturation and that increased NPY correlates with LPL overexpression in the nervous system. Furthermore, we provide molecular insights to the reduced depressive behavior of TTR KOs, as NPY is anti-depressant. Our findings demonstrate that TTR KOs are a model for increased NPY and that TTR plays a role in nervous system physiology.
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Affiliation(s)
- Ana Filipa Nunes
- Molecular Neurobiology, Instituto de Biologia Molecular e Celular-IBMC, Porto, Portugal
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20
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Haugen BR, Jensen DR, Sharma V, Pulawa LK, Hays WR, Krezel W, Chambon P, Eckel RH. Retinoid X receptor gamma-deficient mice have increased skeletal muscle lipoprotein lipase activity and less weight gain when fed a high-fat diet. Endocrinology 2004; 145:3679-85. [PMID: 15087432 DOI: 10.1210/en.2003-1401] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Retinoids, derivatives of vitamin A, induce hypertriglyceridemia through decreased clearance of very low-density lipoprotein by a lipoprotein lipase (LPL)-dependent pathway. The retinoid X receptor (RXR) gamma isotype, which is highly expressed in skeletal muscle, may be important in mediating the effects of retinoids on skeletal muscle metabolism and triglyceride (TG) clearance. RXRgamma-deficient (-/-) mice had lower fasting plasma TG levels compared with wild-type littermates (33.1 +/- 2.0 vs. 51.7 +/- 6.3 mg/dl, respectively; P < 0.05). Skeletal muscle LPL activity was higher in RXRgamma mice (18.7 +/- 2.2 vs. 13.3 +/- 1.3 nmol free fatty acids/min.g; P = 0.03), but LPL activity was not different in adipose and cardiac tissue, suggesting a specific effect of RXRgamma in skeletal muscle. In addition, when exposed to a 14-wk high-fat diet, RXRgamma -/- mice had less weight gain, which was entirely due to lower fat mass (11.9 +/- 1.8 vs. 14.4 +/- 1.1 g; P = 0.01), and leptin levels were also lower in the RXRgamma -/- mice (17.6 +/- 5.0 vs. 30.9 +/- 6.4 ng/ml; P = 0.03). These data suggest that RXRgamma -/- mice are resistant to gain in fat mass in response to high-fat feeding. This occurs, at least in part, through up-regulation of LPL activity in skeletal muscle. An understanding of the mechanisms governing the role of RXR in TG disposal and metabolism may lead to the rational design of RXR-selective agonists and antagonists that may be useful in common disorders such as dyslipidemia and obesity.
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Affiliation(s)
- Bryan R Haugen
- Division of Endocrinology, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA.
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21
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Abstract
Lipoprotein lipase (LPL) regulates the plasma levels of triglyceride and HDL. Three aspects are reviewed. 1) Clinical implications of human LPL gene variations: common mutations and their effects on plasma lipids and coronary heart disease are discussed. 2) LPL actions in the nervous system, liver, and heart: the discussion focuses on LPL and tissue lipid uptake. 3) LPL gene regulation: the LPL promoter and its regulatory elements are described.
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Affiliation(s)
- Martin Merkel
- Department of Medicine, University of Hamburg, Hamburg, Germany. Department of Medicine, University of Colorado Health Sciences Center, Denver, CO, USA
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22
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Ferreira LDMCB, Huey PU, Pulford BE, Ishii DN, Eckel RH. Sciatic nerve lipoprotein lipase is reduced in streptozotocin-induced diabetes and corrected by insulin. Endocrinology 2002; 143:1213-7. [PMID: 11897675 DOI: 10.1210/endo.143.4.8723] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The metabolic abnormalities underlying the cause of diabetic neuropathy have been the subject of much debate. Lipoprotein lipase (LPL) is a 56-kDa enzyme produced by several tissues in the body and has recently been shown in vitro to be expressed in cultured Schwann cells, where it is important in phospholipid synthesis. This suggests a role for LPL in myelin biosynthesis in the peripheral nervous system. The aim of this study was to determine if acute streptozotocin (STZ)-induced diabetes reduces the expression and regulation of sciatic nerve LPL in vivo. Adult Sprague Dawley rats were rendered diabetic via an sc injection of STZ. A decrease in sciatic nerve LPL activity was observed in the STZ-treated rats after just 2 d of diabetes and remained significantly reduced for at least 35 d. The decrease in LPL activity coincided temporally with a drop in motor nerve conduction velocity. Treatment with insulin for 4 d showed a normalization of sciatic nerve LPL activity. These results show that STZ-induced diabetes causes a decrease in LPL activity in the sciatic nerve that, as in other tissues, is reversible with insulin treatment. These data may suggest a role for LPL in the pathophysiology of diabetic neuropathy.
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Affiliation(s)
- L D M C-B Ferreira
- University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
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23
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Gilhuis HJ, ten Donkelaar HJ, Tanke RB, Vingerhoets DM, Zwarts MJ, Verrips A, Gabreëls FJM. Nonmuscular involvement in merosin-negative congenital muscular dystrophy. Pediatr Neurol 2002; 26:30-6. [PMID: 11814732 DOI: 10.1016/s0887-8994(01)00352-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Abstract
The spectrum of nonmuscular involvement in six children with merosin-negative congenital muscular dystrophy is described. In all children, biochemical, neuroradiologic, cardiac, and neurophysiologic studies were performed. Cerebral structures that were myelinated at gestation, including internal capsule, corpus callosum, brainstem, and cerebellar white matter, demonstrated no abnormalities, whereas the periventricular and subcortical white matter, which were myelinated in the first postnatal year, demonstrated signs of leukoencephalopathy. Cerebrospinal fluid analysis revealed an elevated albumin cerebrospinal fluid to serum ratio in the younger children. Electroencephalogram results were abnormal in the two elder children. One child suffered from congestive cardiomyopathy. The increase in nerve conduction velocity in these children over the years lagged behind those of healthy patients, pointing to a demyelinating neuropathy. We conclude that in merosin-negative congenital muscular dystrophy patients, nonmuscular involvement includes the central and peripheral nervous system and the heart. The pattern of myelination of the brain and nerve conduction slowing suggests a myelination arrest. Merosin deficiency can give rise to a congestive cardiomyopathy, which is of no clinical relevance in the majority of children.
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Affiliation(s)
- H Jacobus Gilhuis
- Department of Paediatric Neurology, Neuromuscular Centre, University Medical Centre St Radboud, 6500 HB Nijmegen, The Netherlands
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24
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Huey PU, Waugh KC, Etienne J, Eckel RH. Lipoprotein lipase is expressed in rat sciatic nerve and regulated in response to crush injury. J Lipid Res 2002. [DOI: 10.1016/s0022-2275(20)30182-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022] Open
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25
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Poirier P, Marcell T, Huey PU, Schlaepfer IR, Owens GC, Jensen DR, Eckel RH. Increased intracellular triglyceride in C(2)C(12) muscle cells transfected with human lipoprotein lipase. Biochem Biophys Res Commun 2000; 270:997-1001. [PMID: 10772940 DOI: 10.1006/bbrc.2000.2528] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Much of the knowledge about the cell biology of lipoprotein lipase (LPL) in vitro has been gained from adipose tissue model systems. However, the importance of skeletal muscle lipoprotein lipase (SMLPL) to both lipoprotein and muscle metabolism remains unclear. Although the production of LPL in cultured myocytes has been documented, the amount of enzyme activity produced is small. To develop a more suitable tissue culture model for SMLPL, mouse C(2)C(12) myoblasts were stably transduced with a retroviral vector encoding the full-length human LPL (hLPL) cDNA. Control cells were transduced with a vector encoding beta-galactosidase. LPL expression was assayed as a function of cell growth by measuring LPL activity on days 3, 7, 9, 11, and 14 after subculture. The hLPL-transduced myoblasts increasingly overexpressed both heparin-releasable (HR) and intracellular (IN) LPL activity compared to nontransduced myoblasts (P < 0.001 at Day 11) and myoblasts transduced with the control vector (P < 0.001 at Day 11). This increase occurred while LPL mRNA levels remained stable between days 3 and 14. As expected, IN LPL activity was also increased in the transduced cells. High levels of LPL activity were also obtained after differentiating the C(2)C(12) cells into myotubes by serum deprivation. Additionally, throughout the time course, C(2)/LPL cells had greater amounts of intracellular triglyceride than both the C(2)C(12) and the C(2)/beta-GEO cells (P = 0.005 and P < 0.001, respectively) with the largest differences seen on day 14 of the time course (P = 0.001, C(2)/LPL vs C(2)C(12) (r) or C(2)/beta-GEO cells). Thus, C(2)C(12) myoblasts stably transduced with hLPL markedly overexpressed both HR and IN LPL activity compared to control cells which, in turn, was associated with increases in intracellular triglyceride content. Because LPL regulation in tissues is mostly posttranslational, this new in vitro model will permit the in-depth study of the posttranslational regulation of SMLPL and provide new insights into the fate of lipoprotein-derived fatty acids in muscle.
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Affiliation(s)
- P Poirier
- Division of Endocrinology, Metabolism and Diabetes, University of Colorado Health Sciences Center, Denver, Colorado 80262, USA
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