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Kim P, Scott MR, Meador-Woodruff JH. Abnormal ER quality control of neural GPI-anchored proteins via dysfunction in ER export processing in the frontal cortex of elderly subjects with schizophrenia. Transl Psychiatry 2019; 9:6. [PMID: 30664618 PMCID: PMC6341114 DOI: 10.1038/s41398-018-0359-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2018] [Revised: 10/09/2018] [Accepted: 12/09/2018] [Indexed: 01/22/2023] Open
Abstract
Abnormalities of posttranslational protein modifications (PTMs) have recently been implicated in the pathophysiology of schizophrenia. Glycosylphosphatidylinositols (GPIs) are a class of complex glycolipids, which anchor surface proteins and glycoproteins to the cell membrane. GPI attachment to proteins represents one of the most common PTMs and GPI-associated proteins (GPI-APs) facilitate many cell surface processes, including synapse development and maintenance. Mutations in the GPI processing pathway are associated with intellectual disability, emphasizing the potential role of GPI-APs in cognition and schizophrenia-associated cognitive dysfunction. As initial endoplasmic reticulum (ER)-associated protein processing is essential for GPI-AP function, we measured protein expression of molecules involved in attachment (GPAA1), modification (PGAP1), and ER export (Tmp21) of GPI-APs, in homogenates and in an ER enriched fraction derived from dorsolateral prefrontal cortex (DLPFC) of 15 matched pairs of schizophrenia and comparison subjects. In total homogenate we found a significant decrease in transmembrane protein 21 (Tmp21) and in the ER-enriched fraction we found reduced expression of post-GPI attachment protein (PGAP1). PGAP1 modifies GPI-anchors through inositol deacylation, allowing it to be recognized by Tmp21. Tmp21 is a component of the p24 complex that recognizes GPI-anchored proteins, senses the status of the GPI-anchor, and regulates incorporation into COPII vesicles for export to the Golgi apparatus. Together, these proteins are the molecular mechanisms underlying GPI-AP quality control and ER export. To investigate the potential consequences of a deficit in export and/or quality control, we measured cell membrane-associated expression of known GPI-APs that have been previously implicated in schizophrenia, including GPC1, NCAM, MDGA2, and EPHA1, using Triton X-114 phase separation. Additionally, we tested the sensitivity of those candidate proteins to phosphatidylinositol-specific phospholipase C (PI-PLC), an enzyme that cleaves GPI from GPI-APs. While we did not observe a difference in the amount of these GPI-APs in Triton X-114 phase separated membrane fractions, we found decreased NCAM and GPC1 within the PI-PLC sensitive fraction. These findings suggest dysregulation of ER-associated GPI-AP protein processing, with impacts on post-translational modifications of proteins previously implicated in schizophrenia such as NCAM and GPC1. These findings provide evidence for a deficit in ER protein processing pathways in this illness.
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Affiliation(s)
- Pitna Kim
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA.
| | - Madeline R Scott
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
| | - James H Meador-Woodruff
- Department of Psychiatry and Behavioral Neurobiology, University of Alabama at Birmingham, Birmingham, AL, 35294, USA
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2
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Luzzatto L, Risitano AM. Advances in understanding the pathogenesis of acquired aplastic anaemia. Br J Haematol 2018; 182:758-776. [DOI: 10.1111/bjh.15443] [Citation(s) in RCA: 71] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Affiliation(s)
- Lucio Luzzatto
- Muhimbili University of Health and Allied Sciences; Dar-es-Salaam Tanzania
| | - Antonio M. Risitano
- Department of Clinical Medicine and Surgery; Federico II University; Naples Italy
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Zhang X, Wang D, Jin G, Wang L, Guo Z, Gu G. Synthesis of a tetrasaccharide repeating unit of the exopolysaccharide from Burkholderia multivorans. J Carbohydr Chem 2017. [DOI: 10.1080/07328303.2017.1391275] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Affiliation(s)
- Xin Zhang
- National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan, PR China
| | - Dongyue Wang
- National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan, PR China
| | - Guoxia Jin
- College of Chemistry, Chemical Engineering and Materials Science, Collaborative Innovation Center of Functionalized Probes for Chemical Imaging, Key Laboratory of Molecular and Nano Probes, Ministry of Education, Shandong Normal University, 88 Wenhua Dong Lu, Jinan, PR China
| | - Lizhen Wang
- National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan, PR China
| | - Zhongwu Guo
- National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan, PR China
- Department of Chemistry, University of Florida, 214 Leigh Hall, Gainesville, Florida, United States
| | - Guofeng Gu
- National Glycoengineering Research Center, Shandong Provincial Key Laboratory of Carbohydrate Chemistry and Glycobiology, Shandong University, 27 Shanda Nan Lu, Jinan, PR China
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Phosphorylated glycosphingolipids essential for cholesterol mobilization in Caenorhabditis elegans. Nat Chem Biol 2017; 13:647-654. [PMID: 28369040 DOI: 10.1038/nchembio.2347] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2016] [Accepted: 01/12/2017] [Indexed: 11/08/2022]
Abstract
The nematode Caenorhabditis elegans requires exogenous cholesterol to survive and its depletion leads to early developmental arrest. Thus, tight regulation of cholesterol storage and distribution within the organism is indispensable. Here, we present a novel class of C. elegans phosphorylated glycosphingolipids, phosphoethanolamine glucosylceramides (PEGCs), capable of rescuing larval arrest induced by sterol starvation. We describe the total synthesis of a major PEGC species and demonstrate that the PEGC synthetic counterpart suppresses the dauer-constitutive phenotype of Niemann-Pick C1 (NPC1) and DAF-7/TGF-β mutant worms caused by impaired intracellular sterol trafficking. PEGC biosynthesis depends on functional NPC1 and TGF-β, indicating that these proteins control larval development at least partly through PEGC. Furthermore, glucosylceramide deficiency dramatically reduced PEGC amounts. However, the resulting developmental arrest could be rescued by oversaturation of food with cholesterol. Taken together, these data show that PEGC is essential for C. elegans development through its regulation of sterol mobilization.
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Gurale BP, He Y, Cui X, Dinh H, Dhawane AN, Lucchi NW, Udhayakumar V, Iyer SS. Toward the Development of the Next Generation of a Rapid Diagnostic Test: Synthesis of Glycophosphatidylinositol (GPI) Analogues of Plasmodium falciparum and Immunological Characterization. Bioconjug Chem 2016; 27:2886-2899. [PMID: 27792303 DOI: 10.1021/acs.bioconjchem.6b00542] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
A large number of proteins in malaria parasites are anchored using glycophosphatidylinositols (GPIs) with lipid tails. These GPIs are structurally distinct from human GPIs. Plasmodium falciparum GPIs have been considered as potential vaccine candidates because these molecules are involved in inducing inflammatory responses in human hosts, and natural anti-GPI antibody responses have been shown to be associated with protection against severe disease. GPIs can also be considered as targets for rapid diagnostic tests. Because isolation of native GPIs in large quantities is challenging, development of synthetic GPI molecules can facilitate further exploration of GPI molecules for diagnostics. Here, we report synthesis and immunological characterization of a panel of malaria-specific GPI analogues. A total of three GPI analogues were chemically synthesized and conjugated to a carrier protein to immunize and generate antibodies in rabbits. The rabbit immune sera showed reactivity with synthetic GPIs and native GPIs extracted from P. falciparum parasite, as determined by Luminex and ELISA methods.
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Affiliation(s)
- Bharat P Gurale
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 788 Petit Science Center , 161 Jesse Hill Jr. Drive, Atlanta, Georgia 30302, United States
| | - Yun He
- Atlanta Research and Education Foundation , Atlanta, Georgia 30329, United States
| | - Xikai Cui
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 788 Petit Science Center , 161 Jesse Hill Jr. Drive, Atlanta, Georgia 30302, United States
| | - Hieu Dinh
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 788 Petit Science Center , 161 Jesse Hill Jr. Drive, Atlanta, Georgia 30302, United States
| | - Abasaheb N Dhawane
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 788 Petit Science Center , 161 Jesse Hill Jr. Drive, Atlanta, Georgia 30302, United States
| | - Naomi W Lucchi
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers of Disease Control and Prevention , Atlanta, Georgia 30329, United States
| | - Venkatachalam Udhayakumar
- Malaria Branch, Division of Parasitic Diseases and Malaria, Center for Global Health, Centers of Disease Control and Prevention , Atlanta, Georgia 30329, United States
| | - Suri S Iyer
- Department of Chemistry, Center for Diagnostics and Therapeutics, Georgia State University, 788 Petit Science Center , 161 Jesse Hill Jr. Drive, Atlanta, Georgia 30302, United States
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Abstract
Paroxysmal nocturnal hemoglobinuria (PNH) is a very rare disease that has been investigated for over one century and has revealed unique aspects of the pathogenesis and pathophysiology of a hemolytic anemia. PNH results from expansion of a clone of hematopoietic cells that, as a consequence of an inactivating mutation of the X-linked gene
PIG-A, are deficient in glycosylphosphatidylinositol (GPI)-linked proteins: since these include the surface membrane complement-regulatory proteins CD55 and CD59, the red cells arising from this clone are exquisitely sensitive to lysis by activated complement. Until a decade ago, the treatment options for PNH were either supportive treatment – often including blood transfusion, anti-thrombosis prophylaxis, and sometimes thrombolytic therapy – or allogeneic bone marrow transplantation. Since 2007, PNH has received renewed and much wider attention because a new form of treatment has become available, namely complement blockade through the anti-C5 monoclonal antibody eculizumab. This brief review focuses on two specific aspects of PNH: (1) response to eculizumab, variability of response, and how this new agent has impacted favorably on the outlook and on the quality of life of patients; and (2) with respect to pathogenesis, new evidence supports the notion that expansion of the PNH clone results from T-cell-mediated auto-immune damage to hematopoietic stem cells, with the GPI molecule as target. Indeed, GPI-specific CD8+ T cells – which have been identified in PNH patients – would spare selectively GPI-negative stem cells, thus enabling them to re-populate the marrow of a patient who would otherwise have aplastic anemia.
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Affiliation(s)
- Lucio Luzzatto
- University of Firenze, Piazza di San Marco, 4, Florence, 50121, Italy; Department of Haematology, Muhimbili University Hospital, Dar es Salaam, Tanzania
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Zhang X, Gu G, Guo Z. Synthesis of a Trisaccharide Repeating Unit of the O-Antigen fromBurkholderia multivoransand Its Oligomers. European J Org Chem 2015. [DOI: 10.1002/ejoc.201500964] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
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Wang L, Feng S, An L, Gu G, Guo Z. Synthetic and Immunological Studies of Mycobacterial Lipoarabinomannan Oligosaccharides and Their Protein Conjugates. J Org Chem 2015; 80:10060-75. [DOI: 10.1021/acs.joc.5b01686] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Affiliation(s)
- Lizhen Wang
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
| | - Shaojie Feng
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
| | - Lian An
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
| | - Guofeng Gu
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
| | - Zhongwu Guo
- National Glycoengineering
Research Center, School of Life Science, Shandong University, Jinan 250100, China
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Francesconi O, Nativi C, Gabrielli G, Gentili M, Palchetti M, Bonora B, Roelens S. Pyrrolic Tripodal Receptors for the Molecular Recognition of Carbohydrates: Ditopic Receptors for Dimannosides. Chemistry 2013; 19:11742-52. [DOI: 10.1002/chem.201204298] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2012] [Indexed: 11/08/2022]
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Glycosylphosphatidylinositol-specific, CD1d-restricted T cells in paroxysmal nocturnal hemoglobinuria. Blood 2013; 121:2753-61. [PMID: 23372165 DOI: 10.1182/blood-2012-11-469353] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
The mechanism of bone marrow failure (BMF) in paroxysmal nocturnal hemoglobinuria (PNH) is not yet known. Because in PNH the biosynthesis of the glycolipid molecule glycosylphosphatidylinositol (GPI) is disrupted in hematopoietic stem and progenitor cells by a somatic mutation in the PIG-A gene, BMF might result from an autoimmune attack, whereby T cells target GPI in normal cells, whereas PIG-A mutant GPI-negative cells are spared. In a deliberate test of this hypothesis, we have demonstrated in PNH patients the presence of CD8(+) T cells reactive against antigen-presenting cells (APCs) loaded with GPI. These T cells were significantly more abundant in PNH patients than in healthy controls; their reactivity depended on CD1d expression and they increased upon coculture with CD1d-expressing, GPI-positive APCs. In GPI-specific T cells captured by CD1d dimer technology, we identified, through global T-cell receptor α (TCRα) analysis, an invariant TCRVα21 sequence, which was then found at frequencies higher than background in the TCR repertoire of 6 of 11 PNH patients. Thus, a novel, autoreactive, CD1d-restricted, GPI-specific T-cell population, enriched in an invariant TCRα chain, is expanded in PNH patients and may be responsible for BMF in PNH.
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