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Lymperopoulos D, Dedemadi AG, Voulgari ML, Georgiou E, Dafnis I, Mountaki C, Panagopoulou EA, Karvelas M, Chiou A, Karathanos VT, Chroni A. Corinthian Currants Promote the Expression of Paraoxonase-1 and Enhance the Antioxidant Status in Serum and Brain of 5xFAD Mouse Model of Alzheimer's Disease. Biomolecules 2024; 14:426. [PMID: 38672443 PMCID: PMC11047902 DOI: 10.3390/biom14040426] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/07/2024] [Revised: 03/26/2024] [Accepted: 03/27/2024] [Indexed: 04/28/2024] Open
Abstract
Paraoxonase-1 (PON1), a serum antioxidant enzyme, has been implicated in Alzheimer's disease (AD) pathogenesis that involves early oxidative damage. Corinthian currants and their components have been shown to display antioxidant and other neuroprotective effects in AD. We evaluated the effect of a Corinthian currant paste-supplemented diet (CurD), provided to 1-month-old 5xFAD mice for 1, 3, and 6 months, on PON1 activity and levels of oxidation markers in serum and the brain of mice as compared to a control diet (ConD) or glucose/fructose-matched diet (GFD). Administration of CurD for 1 month increased PON1 activity and decreased oxidized lipid levels in serum compared to ConD and GFD. Longer-term administration of CurD did not, however, affect serum PON1 activity and oxidized lipid levels. Furthermore, CurD administered for 1 and 3 months, but not for 6 months, increased PON1 activity and decreased free radical levels in the cortex of mice compared to ConD and GFD. To probe the mechanism for the increased PON1 activity in mice, we studied the effect of Corinthian currant polar phenolic extract on PON1 activity secreted by Huh-7 hepatocytes or HEK293 cells transfected with a PON1-expressing plasmid. Incubation of cells with the extract led to a dose-dependent increase of secreted PON1 activity, which was attributed to increased cellular PON1 expression. Collectively, our findings suggest that phenolics in Corinthian currants can increase the hepatic expression and activity of antioxidant enzyme PON1 and that a Corinthian currant-supplemented diet during the early stages of AD in mice reduces brain oxidative stress.
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Affiliation(s)
- Dimitris Lymperopoulos
- Institute of Biosciences and Applications, National Center for Scientific Research “Demokritos”, Agia Paraskevi, 15341 Athens, Greece
- Department of Biology, National and Kapodistrian University of Athens, Zografou, 15784 Athens, Greece
| | - Anastasia-Georgia Dedemadi
- Institute of Biosciences and Applications, National Center for Scientific Research “Demokritos”, Agia Paraskevi, 15341 Athens, Greece
- Department of Chemistry, National and Kapodistrian University of Athens, Zografou, 15784 Athens, Greece
| | - Maria-Lydia Voulgari
- Institute of Biosciences and Applications, National Center for Scientific Research “Demokritos”, Agia Paraskevi, 15341 Athens, Greece
- Department of Chemistry, National and Kapodistrian University of Athens, Zografou, 15784 Athens, Greece
| | - Eirini Georgiou
- Institute of Biosciences and Applications, National Center for Scientific Research “Demokritos”, Agia Paraskevi, 15341 Athens, Greece
- Department of Chemistry, National and Kapodistrian University of Athens, Zografou, 15784 Athens, Greece
| | - Ioannis Dafnis
- Institute of Biosciences and Applications, National Center for Scientific Research “Demokritos”, Agia Paraskevi, 15341 Athens, Greece
| | - Christina Mountaki
- Institute of Biosciences and Applications, National Center for Scientific Research “Demokritos”, Agia Paraskevi, 15341 Athens, Greece
| | - Eirini A. Panagopoulou
- Laboratory of Chemistry-Biochemistry-Physical Chemistry of Foods, Department of Dietetics and Nutrition, Harokopio University, 17676 Kallithea, Greece (A.C.); (V.T.K.)
| | - Michalis Karvelas
- Research and Development Department, Agricultural Cooperatives’ Union of Aeghion, 25100 Aeghion, Greece;
| | - Antonia Chiou
- Laboratory of Chemistry-Biochemistry-Physical Chemistry of Foods, Department of Dietetics and Nutrition, Harokopio University, 17676 Kallithea, Greece (A.C.); (V.T.K.)
| | - Vaios T. Karathanos
- Laboratory of Chemistry-Biochemistry-Physical Chemistry of Foods, Department of Dietetics and Nutrition, Harokopio University, 17676 Kallithea, Greece (A.C.); (V.T.K.)
| | - Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research “Demokritos”, Agia Paraskevi, 15341 Athens, Greece
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Dafnis I, Tsouka AN, Gkolfinopoulou C, Tellis CC, Chroni A, Tselepis AD. PCSK9 is minimally associated with HDL but impairs the anti-atherosclerotic HDL effects on endothelial cell activation. J Lipid Res 2022; 63:100272. [PMID: 36067830 PMCID: PMC9526147 DOI: 10.1016/j.jlr.2022.100272] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Revised: 07/30/2022] [Accepted: 07/30/2022] [Indexed: 11/30/2022] Open
Abstract
Proprotein Convertase Subtilisin/Kexin type 9 (PCSK9) regulates the cell-surface localization of LDL receptors in hepatocytes and is associated with LDL and lipoprotein(a) [Lp(a)] uptake, reducing blood concentrations. However, the connection between PCSK9 and HDL is unclear. Here, we investigated the association of plasma PCSK9 with HDL subpopulations and examined the effects of PCSK9 on the atheroprotective function of HDL. We examined the association of PCSK9 with HDL in apoB-depleted plasma by ELISA, native PAGE, and immunoblotting. Our analyses showed that upon apoB-depletion, total circulating PCSK9 levels were 32% of those observed in normolipidemic plasma, and only 6% of PCSK9 in the apoB-depleted plasma, including both the mature and furin-cleaved forms, was associated with HDL. We also show human recombinant PCSK9 abolished the capacity of reconstituted HDL to reduce the formation of ROS in endothelial cells, while a PCSK9-blocking antibody enhanced the capacity of human HDL (in apoB-depleted plasma) to reduce ROS formation in endothelial cells and promote endothelial cell migration. Overall, our findings suggest that PCSK9 is only minimally associated with HDL particles, but PCSK9 in apoB-depleted plasma can affect the atheroprotective properties of HDL related to preservation of endothelial function. This study contributes to the elucidation of the pathophysiological role of plasma PCSK9 and highlights further the anti-atherosclerotic effect of PCSK9 inhibition.
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Affiliation(s)
- Ioannis Dafnis
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Agia Paraskevi, Athens, Greece
| | - Aikaterini N Tsouka
- Atherothrombosis Research Centre, Department of Chemistry, University of Ioannina, Ioannina, Greece
| | - Christina Gkolfinopoulou
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Agia Paraskevi, Athens, Greece
| | - Constantinos C Tellis
- Atherothrombosis Research Centre, Department of Chemistry, University of Ioannina, Ioannina, Greece
| | - Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Agia Paraskevi, Athens, Greece
| | - Alexandros D Tselepis
- Atherothrombosis Research Centre, Department of Chemistry, University of Ioannina, Ioannina, Greece.
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Tsouka A, Dafnis I, Tellis C, Gkolfinopoulou C, Chroni A, Tselepis A. PCSK9 is differentially distributed among HDL subpopulations. Atherosclerosis 2022. [DOI: 10.1016/j.atherosclerosis.2022.06.442] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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Mountaki C, Dafnis I, Panagopoulou EA, Vasilakopoulou PB, Karvelas M, Chiou A, Karathanos VT, Chroni A. Mechanistic insight into the capacity of natural polar phenolic compounds to abolish Alzheimer's disease-associated pathogenic effects of apoE4 forms. Free Radic Biol Med 2021; 171:284-301. [PMID: 34019932 DOI: 10.1016/j.freeradbiomed.2021.05.022] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Revised: 05/08/2021] [Accepted: 05/11/2021] [Indexed: 01/01/2023]
Abstract
Polar phenols found in plant foods have been suggested to act protectively against pathogenic processes underlying Alzheimer's disease (AD), such as oxidative stress. The major risk factor for AD is apolipoprotein E4 (apoE4) and apoE4 forms can affect AD-related processes. It was shown previously that the hereditary apoE4 mutant apoE4[L28P], as well as the apoE4 fragment apoE4-165, induce neuronal oxidative stress. The effect of polar phenols on AD-related pathogenic functions of apoE4 forms is largely unexplored. The aim was to examine the effect of Corinthian currant polar phenolic extract and specific polar phenols resveratrol, quercetin, kaempferol and epigallocatechin gallate on AD-related functions of apoE4 forms. The polar phenolic extract and the individual compounds restored the viability of human neuroblastoma SK-N-SH cells in the presence of lipoprotein-associated apoE4[L28P] and prevented changes in cellular redox status. Furthermore, resveratrol, quercetin, kaempferol and epigallocatechin gallate prevented redox status changes induced by Aβ42 uptake in SK-N-SH cells treated with lipid-free apoE4[L28P] or apoE4-165. Investigation of the molecular mechanism of action of these polar phenols showed that resveratrol prevented cellular Aβ42 uptake via changes in cell membrane fluidity. Interestingly, kaempferol prevented cellular Aβ42 uptake by apoE4[L28P], but not by apoE4-165, due to a modulating effect on apoE4[L28P] secondary structure and stability. The action of quercetin and epigallocatechin gallate could be attributed to free radical-scavenging or other protective activity. Overall, it is shown for the first time that natural compounds could modify the structure of apoE4 forms and ameliorate AD-related pathogenic effects of apoE4 forms.
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Affiliation(s)
- Christina Mountaki
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Agia Paraskevi, Athens, Greece
| | - Ioannis Dafnis
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Agia Paraskevi, Athens, Greece
| | - Eirini A Panagopoulou
- Laboratory of Chemistry-Biochemistry-Physical Chemistry of Foods, Department of Dietetics and Nutrition, Harokopio University, Kallithea, Greece
| | - Paraskevi B Vasilakopoulou
- Laboratory of Chemistry-Biochemistry-Physical Chemistry of Foods, Department of Dietetics and Nutrition, Harokopio University, Kallithea, Greece
| | - Michalis Karvelas
- Research and Development Department, Agricultural Cooperatives' Union of Aeghion, Aeghion, Greece
| | - Antonia Chiou
- Laboratory of Chemistry-Biochemistry-Physical Chemistry of Foods, Department of Dietetics and Nutrition, Harokopio University, Kallithea, Greece
| | - Vaios T Karathanos
- Laboratory of Chemistry-Biochemistry-Physical Chemistry of Foods, Department of Dietetics and Nutrition, Harokopio University, Kallithea, Greece; Research and Development Department, Agricultural Cooperatives' Union of Aeghion, Aeghion, Greece
| | - Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Agia Paraskevi, Athens, Greece.
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Gkolfinopoulou C, Soukou F, Dafnis I, Kellici TF, Sanoudou D, Mavromoustakos T, Stratikos E, Chroni A. Structure-function analysis of naturally occurring apolipoprotein A-I L144R, A164S and L178P mutants provides insight on their role on HDL levels and cardiovascular risk. Cell Mol Life Sci 2020; 78:1523-1544. [PMID: 32666307 DOI: 10.1007/s00018-020-03583-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 06/03/2020] [Accepted: 06/22/2020] [Indexed: 01/04/2023]
Abstract
Naturally occurring point mutations in apolipoprotein A-I (apoA-I), the major protein component of high-density lipoprotein (HDL), may affect plasma HDL-cholesterol levels and cardiovascular risk. Here, we evaluated the effect of human apoA-I mutations L144R (associated with low HDL-cholesterol), L178P (associated with low HDL-cholesterol and increased cardiovascular risk) and A164S (associated with increased cardiovascular risk and mortality without low HDL-cholesterol) on the structural integrity and functions of lipid-free and lipoprotein-associated apoA-I in an effort to explain the phenotypes of subjects carrying these mutations. All three mutants, in lipid-free form, presented structural and thermodynamic aberrations, with apoA-I[L178P] presenting the greatest thermodynamic destabilization. Additionally, apoA-I[L178P] displayed reduced ABCA1-mediated cholesterol efflux capacity. When in reconstituted HDL (rHDL), apoA-I[L144R] and apoA-I[L178P] were more thermodynamically destabilized compared to wild-type apoA-I, both displayed reduced SR-BI-mediated cholesterol efflux capacity and apoA-I[L144R] showed severe LCAT activation defect. ApoA-I[A164S] was thermodynamically unaffected when in rHDL, but exhibited a series of functional defects. Specifically, it had reduced ABCG1-mediated cholesterol and 7-ketocholesterol efflux capacity, failed to reduce ROS formation in endothelial cells and had reduced capacity to induce endothelial cell migration. Mechanistically, the latter was due to decreased capacity of rHDL-apoA-I[A164S] to activate Akt kinase possibly by interacting with endothelial LOX-1 receptor. The impaired capacity of rHDL-apoA-I[A164S] to preserve endothelial function may be related to the increased cardiovascular risk for this mutation. Overall, our structure-function analysis of L144R, A164S and L178P apoA-I mutants provides insights on how HDL-cholesterol levels and/or atheroprotective properties of apoA-I/HDL are impaired in carriers of these mutations.
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Affiliation(s)
- Christina Gkolfinopoulou
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Agia Paraskevi, 15341, Athens, Greece
| | - Faye Soukou
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Agia Paraskevi, 15341, Athens, Greece
| | - Ioannis Dafnis
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Agia Paraskevi, 15341, Athens, Greece
| | - Tahsin F Kellici
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimioupolis Zografou, Athens, Greece
| | - Despina Sanoudou
- 4th Department of Internal Medicine, Clinical Genomics and Pharmacogenomics Unit, 'Attikon' Hospital, Medical School, National and Kapodistrian University of Athens, Athens, Greece.,Molecular Biology Division, Biomedical Research Foundation of the Academy of Athens, Athens, Greece.,Center for New Biotechnologies and Precision Medicine, Medical School, National and Kapodistrian University of Athens, Athens, Greece
| | - Thomas Mavromoustakos
- Laboratory of Organic Chemistry, Department of Chemistry, National and Kapodistrian University of Athens, Panepistimioupolis Zografou, Athens, Greece
| | - Efstratios Stratikos
- Protein Chemistry Laboratory, Institute of Nuclear and Radiological Sciences and Technology, Energy and Safety, National Center for Scientific Research "Demokritos", Agia Paraskevi, Athens, Greece
| | - Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Agia Paraskevi, 15341, Athens, Greece.
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Divolis G, Stavropoulos A, Manioudaki M, Apostolidou A, Doulou A, Gavriil A, Dafnis I, Chroni A, Mummery C, Xilouri M, Sideras P. Activation of both transforming growth factor-β and bone morphogenetic protein signalling pathways upon traumatic brain injury restrains pro-inflammatory and boosts tissue reparatory responses of reactive astrocytes and microglia. Brain Commun 2019; 1:fcz028. [PMID: 32954268 PMCID: PMC7425383 DOI: 10.1093/braincomms/fcz028] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2019] [Revised: 09/24/2019] [Accepted: 10/07/2019] [Indexed: 02/06/2023] Open
Abstract
Various ligands and receptors of the transforming growth factor-β superfamily have been found upregulated following traumatic brain injury; however, the role of this signalling system in brain injury pathophysiology is not fully characterized. To address this, we utilized an acute stab wound brain injury model to demonstrate that hallmarks of transforming growth factor-β superfamily system activation, such as levels of phosphorylated Smads, ligands and target genes for both transforming growth factor-β and bone morphogenetic protein pathways, were upregulated within injured tissues. Using a bone morphogenetic protein-responsive reporter mouse model, we showed that activation of the bone morphogenetic protein signalling pathway involves primarily astrocytes that demarcate the wound area. Insights regarding the potential role of transforming growth factor-β superfamily activation in glia cells within the injured tissues were obtained indirectly by treating purified reactive astrocytes and microglia with bone morphogenetic protein-4 or transforming growth factor-β1 and characterizing changes in their transcriptional profiles. Astrocytes responded to both ligands with considerably overlapping profiles, whereas, microglia responded selectively to transforming growth factor-β1. Novel pathways, crucial for repair of tissue-injury and blood-brain barrier, such as activation of cholesterol biosynthesis and transport, production of axonal guidance and extracellular matrix components were upregulated by transforming growth factor-β1 and/or bone morphogenetic protein-4 in astrocytes. Moreover, both ligands in astrocytes and transforming growth factor-β1 in microglia shifted the phenotype of reactive glia cells towards the anti-inflammatory and tissue reparatory 'A2'-like and 'M0/M2'-like phenotypes, respectively. Increased expression of selected key components of the in vitro modulated pathways and markers of 'A2'-like astrocytes was confirmed within the wound area, suggesting that these processes could also be modulated in situ by the integrated action of transforming growth factor-β and/or bone morphogenetic protein-mediated signalling. Collectively, our study provides a comprehensive comparative analysis of transforming growth factor-β superfamily signalling in reactive astrocytes and microglia and points towards a crucial role of both transforming growth factor-β and bone morphogenetic protein pathways in modulating the inflammatory and brain injury reparatory functions of activated glia cells.
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Affiliation(s)
- Georgios Divolis
- Center for Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece
| | - Athanasios Stavropoulos
- Center for Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece
| | - Maria Manioudaki
- Center for Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece
| | - Anastasia Apostolidou
- Center for Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece
| | - Athanasia Doulou
- Center for Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece
| | - Ariana Gavriil
- Center for Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece
| | - Ioannis Dafnis
- Institute of Biosciences and Applications, National Center for Scientific Research-Demokritos, 15341 Athens, Greece
| | - Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research-Demokritos, 15341 Athens, Greece
| | - Christine Mummery
- Department of Anatomy and Embryology, Leiden University Medical Center, 2333ZC Leiden, The Netherlands
| | - Maria Xilouri
- Center for Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece
| | - Paschalis Sideras
- Center for Clinical Research, Experimental Surgery and Translational Research, Biomedical Research Foundation of the Academy of Athens, 11527 Athens, Greece
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Dafnis I, Argyri L, Chroni A. Amyloid-peptide β 42 Enhances the Oligomerization and Neurotoxicity of apoE4: The C-terminal Residues Leu279, Lys282 and Gln284 Modulate the Structural and Functional Properties of apoE4. Neuroscience 2018; 394:144-155. [PMID: 30367942 DOI: 10.1016/j.neuroscience.2018.10.026] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 10/12/2018] [Accepted: 10/15/2018] [Indexed: 11/25/2022]
Abstract
Apolipoprotein E4 (apoE4), one of the three apoE isoforms, is the strongest factor for raising the risk for late-onset Alzheimer's disease (AD) and has been proposed to play a major role in AD pathogenesis. Amyloid-peptide β 42 (Aβ42) has also been proposed to affect neuronal degeneration and AD pathogenesis, possibly by interacting with apoE. Previous studies have shown that the functions of apoE forms can be dictated by their structural and biophysical properties. Here we show that apoE4 can form SDS-stable oligomers, possibly reflecting aggregated forms, which increase following incubation of apoE4 with Aβ42. In addition, extracellular apoE4 is cytotoxic for human neuroblastoma SK-N-SH cells, while Aβ42 enhances the cytotoxicity of apoE4. Carboxyl-terminal point mutations L279Q, K282A or Q284A reduced the capacity of apoE4 to form SDS-stable oligomers, as well as its cytotoxicity, both in the absence and presence of Aβ42. Structural and thermodynamic analyses showed that all three apoE4 mutants have significantly increased α-helical and decreased β-sheet content, have reduced portion of hydrophobic surfaces exposed to the solvent and have a reduced conformational stability during chemical denaturation. Overall, our data highlight a pathogenic role of apoE4 that could be linked to the capacity of the protein to form oligomeric species especially in the presence of Aβ42 and to induce cytotoxicity. Carboxyl-terminal residues L279, K282 or Q284 appear to be involved in the conformation of apoE4 that may underlie the protein's functional properties related to neurotoxicity.
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Affiliation(s)
- Ioannis Dafnis
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Agia Paraskevi, Athens 15341, Greece
| | - Letta Argyri
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Agia Paraskevi, Athens 15341, Greece
| | - Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Agia Paraskevi, Athens 15341, Greece.
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Bourtsala A, Dafnis I, Chroni A, Farmaki T, Galanopoulou D. Study of the Involvement of Phosphatidic Acid Formation in the Expression of Wound-Responsive Genes in Cotton. Lipids 2018; 53:589-599. [PMID: 30198579 DOI: 10.1002/lipd.12058] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2018] [Revised: 06/13/2018] [Accepted: 06/13/2018] [Indexed: 11/12/2022]
Abstract
Plants use phospholipase D (PLD, EC 3.1.4.4)/phosphatidic acid (PtdOH) for the transduction of environmental signals including those coming from wounding. Based on our previous findings suggesting that wound-induced PLDα-derived PtdOH can act as a local signaling molecule in cotton (Gossypium hirsutum), we show that wounding immediately increases local NADPH oxidase (NADPHox) and cellulose synthase A (CeSA) gene expression. After developing a novel fluorimetric assay for the investigation of n-butanol inhibitory effect on PLD activity, we show that only NADPHox gene upregulation is reduced when n-butanol is applied prior to wounding. This suggests that NADPHox is a possible downstream target of PLD function, while a different CeSA-involving response system may exist in cotton. Overall, this study provides new knowledge on signal-transduction mechanisms following wounding of cotton leaves.
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Affiliation(s)
- Angeliki Bourtsala
- Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, 15771, Athens, Greece
| | - Ioannis Dafnis
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Patr. Gregoriou E & 27 Neapoleos Str, 15341 Agia Paraskevi, Greece
| | - Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos", Patr. Gregoriou E & 27 Neapoleos Str, 15341 Agia Paraskevi, Greece
| | - Theodora Farmaki
- Institute of Applied Biosciences, Centre for Research and Technology, 6th km Charilaou-Thermi Rd, 57001 Thermi, Thessaloniki, Greece
| | - Dia Galanopoulou
- Department of Chemistry, National and Kapodistrian University of Athens, Panepistimiopolis, 15771, Athens, Greece
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Jauhiainen M, Dafnis I, Metso J, Zannis V, Chroni A. Effects of apoE variants on PLTP interaction and activation of low and high activity forms of PLTP. Atherosclerosis 2016. [DOI: 10.1016/j.atherosclerosis.2016.07.629] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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Dafnis I, Metso J, Zannis VI, Jauhiainen M, Chroni A. Influence of Isoforms and Carboxyl-Terminal Truncations on the Capacity of Apolipoprotein E To Associate with and Activate Phospholipid Transfer Protein. Biochemistry 2015; 54:5856-66. [PMID: 26337529 DOI: 10.1021/acs.biochem.5b00681] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Phospholipid transfer protein (PLTP), a main protein in lipid and lipoprotein metabolism, exists in high-activity (HA-PLTP) and low-activity (LA-PLTP) forms in human plasma. Proper phospholipid transfer activity of PLTP is modulated by interactions with various apolipoproteins (apo) including apoE. The domains of apoE involved in interactions with PLTP are not known. Here we analyzed the capacity of recombinant apoE isoforms and apoE4 mutants with progressive carboxyl-terminal deletions to bind to and activate HA-PLTP and LA-PLTP. Our analyses demonstrated that lipid-free apoE isoforms bind to both HA-PLTP and LA-PLTP, resulting in phospholipid transfer activation, with apoE3 inducing the highest PLTP activation. The isoform-specific differences in apoE/PLTP binding and PLTP activation were abolished following apoE lipidation. Lipid-free apoE4[Δ(260-299)], apoE4[Δ(230-299)], apoE4[Δ(203-299)], and apoE4[Δ(186-299)] activated HA-PLTP by 120-160% compared to full-length apoE4. Lipid-free apoE4[Δ(186-299)] also activated LA-PLTP by 85% compared to full-length apoE4. All lipidated truncated apoE4 forms displayed a similar effect on HA-PLTP and LA-PLTP activity as full-length apoE4. Strikingly, lipid-free or lipidated full-length apoE4 and apoE4[Δ(186-299)] demonstrated similar binding capacity to LA-PLTP and HA-PLTP. Biophysical studies showed that the carboxyl-terminal truncations of apoE4 resulted in small changes of the structural or thermodynamic properties of lipidated apoE4, that were much less pronounced compared to changes observed previously for lipid-free apoE4. Overall, our findings show an isoform-dependent binding to and activation of PLTP by lipid-free apoE. Furthermore, the domain of apoE4 required for PLTP activation resides within its amino-terminal 1-185 region. The apoE/PLTP interactions can be modulated by the conformation and lipidation state of apoE.
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Affiliation(s)
- Ioannis Dafnis
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos" , Agia Paraskevi 15310, Athens, Greece
| | - Jari Metso
- Genomics and Biomarkers Unit, Biomedicum, National Institute for Health and Welfare , Helsinki 00290, Finland
| | - Vassilis I Zannis
- Departments of Medicine and Biochemistry, Molecular Genetics, Whitaker Cardiovascular Institute, Boston University School of Medicine , Boston, Massachusetts 02118, United States
| | - Matti Jauhiainen
- Genomics and Biomarkers Unit, Biomedicum, National Institute for Health and Welfare , Helsinki 00290, Finland
| | - Angeliki Chroni
- Institute of Biosciences and Applications, National Center for Scientific Research "Demokritos" , Agia Paraskevi 15310, Athens, Greece
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Fotakis P, Vezeridis A, Dafnis I, Chroni A, Kardassis D, Zannis VI. apoE3[K146N/R147W] acts as a dominant negative apoE form that prevents remnant clearance and inhibits the biogenesis of HDL. J Lipid Res 2014; 55:1310-23. [PMID: 24776540 DOI: 10.1194/jlr.m048348] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/17/2014] [Indexed: 12/11/2022] Open
Abstract
The K146N/R147W substitutions in apoE3 were described in patients with a dominant form of type III hyperlipoproteinemia. The effects of these mutations on the in vivo functions of apoE were studied by adenovirus-mediated gene transfer in different mouse models. Expression of the apoE3[K146N/R147W] mutant in apoE-deficient (apoE(-/-)) or apoA-I-deficient (apoA-I(-/-))×apoE(-/-) mice exacerbated the hypercholesterolemia and increased plasma apoE and triglyceride levels. In apoE(-/-) mice, the apoE3[K146N/R147W] mutant displaced apoA-I from the VLDL/LDL/HDL region and caused the accumulation of discoidal apoE-containing HDL. The WT apoE3 cleared the cholesterol of apoE(-/-) mice without induction of hypertriglyceridemia and promoted formation of spherical HDL. A unique property of the truncated apoE3[K146N/R147W]202 mutant, compared with similarly truncated apoE forms, is that it did not correct the hypercholesterolemia. The contribution of LPL and LCAT in the induction of the dyslipidemia was studied. Treatment of apoE(-/-) mice with apoE3[K146N/R147W] and LPL corrected the hypertriglyceridemia, but did not prevent the formation of discoidal HDL. Treatment with LCAT corrected hypertriglyceridemia and generated spherical HDL. The combined data indicate that the K146N/R147W substitutions convert the full-length and the truncated apoE3[K146N/R147W] mutant into a dominant negative ligand that prevents receptor-mediated remnant clearance, exacerbates the dyslipidemia, and inhibits the biogenesis of HDL.
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Affiliation(s)
- Panagiotis Fotakis
- Molecular Genetics, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118 Department of BiochemistryUniversity of Crete Medical School, Heraklion, Crete, Greece 71110 Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology of Hellas, Heraklion, Crete, Greece 71003
| | - Alexander Vezeridis
- Molecular Genetics, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118
| | - Ioannis Dafnis
- National Center for Scientific Research "Demokritos" Athens, Greece 15310
| | - Angeliki Chroni
- National Center for Scientific Research "Demokritos" Athens, Greece 15310
| | - Dimitris Kardassis
- Department of BiochemistryUniversity of Crete Medical School, Heraklion, Crete, Greece 71110 Institute of Molecular Biology and Biotechnology, Foundation for Research and Technology of Hellas, Heraklion, Crete, Greece 71003
| | - Vassilis I Zannis
- Molecular Genetics, Whitaker Cardiovascular Institute, Boston University School of Medicine, Boston, MA 02118
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Argyri L, Dafnis I, Theodossiou TA, Gantz D, Stratikos E, Chroni A. Molecular basis for increased risk for late-onset Alzheimer disease due to the naturally occurring L28P mutation in apolipoprotein E4. J Biol Chem 2014; 289:12931-45. [PMID: 24644280 DOI: 10.1074/jbc.m113.538124] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
The apolipoprotein (apo) E4 isoform has consistently emerged as a susceptibility factor for late-onset Alzheimer disease (AD), although the exact mechanism is not clear. A rare apoE4 mutant, apoE4[L28P] Pittsburgh, burdens carriers with an added risk for late-onset AD and may be a useful tool for gaining insights into the role of apoE4 in disease pathogenesis. Toward this end, we evaluated the effect of the L28P mutation on the structural and functional properties of apoE4. ApoE4[L28P] was found to have significantly perturbed thermodynamic properties, to have reduced helical content, and to expose a larger portion of the hydrophobic surface to the solvent. Furthermore, this mutant is thermodynamically destabilized and more prone to proteolysis. When interacting with lipids, apoE4[L28P] formed populations of lipoprotein particles with structural defects. The structural perturbations brought about by the mutation were accompanied by aberrant functions associated with the pathogenesis of AD. Specifically, apoE4[L28P] promoted the cellular uptake of extracellular amyloid β peptide 42 (Aβ42) by human neuroblastoma SK-N-SH cells as well as by primary mouse neuronal cells and led to increased formation of intracellular reactive oxygen species that persisted for at least 24 h. Furthermore, lipoprotein particles containing apoE4[L28P] induced intracellular reactive oxygen species formation and reduced SK-N-SH cell viability. Overall, our findings suggest that the L28P mutation leads to significant structural and conformational perturbations in apoE4 and can induce functional defects associated with neuronal Aβ42 accumulation and oxidative stress. We propose that these structural and functional changes underlie the observed added risk for AD development in carriers of apoE4[L28P].
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Affiliation(s)
- Letta Argyri
- From the Institute of Biosciences and Applications
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Dafnis I, Tzinia AK, Tsilibary EC, Zannis VI, Chroni A. An apolipoprotein E4 fragment affects matrix metalloproteinase 9, tissue inhibitor of metalloproteinase 1 and cytokine levels in brain cell lines. Neuroscience 2012; 210:21-32. [PMID: 22445724 DOI: 10.1016/j.neuroscience.2012.03.013] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2011] [Revised: 03/02/2012] [Accepted: 03/02/2012] [Indexed: 02/07/2023]
Abstract
Apolipoprotein (apo) E4 isoform, a major risk factor for Alzheimer disease (AD), is more susceptible to proteolysis than apoE2 and apoE3 isoforms. ApoE4 fragments have been found in AD patients' brain. In the present study, we examined the effect of full-length apoE4 and apoE4 fragments apoE4[Δ(186-299)] and apoE4[Δ(166-299)] on inflammation in human neuroblastoma SK-N-SH and human astrocytoma SW-1783 cells. Western blot and zymography analysis showed that treatment of SK-N-SH cells with apoE4[Δ(186-299)], but not full-length apoE4 or the shorter apoE4[Δ(166-299)] fragment, leads to increased extracellular levels of matrix metalloproteinase 9 (MMP9) and tissue inhibitor of metalloproteinase 1 (TIMP1). Real-time PCR showed that interleukin (IL)-1β gene expression is also increased in SK-N-SH cells treated with apoE4[Δ(186-299)]. Treatment of SK-N-SH cells with IL-1β leads to increased MMP9 and TIMP1 extracellular levels, suggesting that the induction of IL-1β may be the mechanism by which apoE4[Δ(186-299)] regulates MMP9 and TIMP1 levels in these cells. In contrast to SK-N-SH cells, treatment of SW-1783 cells with apoE4[Δ(186-299)], and to a lesser extent with apoE4, leads to increased TIMP1 extracellular levels without affecting MMP9 levels. Additionally, apoE4[Δ(186-299)] leads to decreased IL-10 gene expression in SK-N-SH cells, whereas both apoE4 and apoE4[Δ(186-299)] lead to decreased TNFα gene expression without affecting IL-1β and IL-10 gene expression in SW-1783 cells. Overall, our findings indicate that a specific apoE4 fragment (apoE4[Δ(186-299)]), with molecular mass similar that of apoE4 fragments detected in AD patients' brain, can influence the level of inflammatory molecules in brain cell lines. It is possible that these phenomena contribute to AD pathogenesis.
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Affiliation(s)
- I Dafnis
- National Center for Scientific Research Demokritos, Institute of Biology, Agia Paraskevi, Athens 15310, Greece
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Dafnis I, Stratikos E, Tzinia A, Tsilibary EC, Zannis VI, Chroni A. An apolipoprotein E4 fragment can promote intracellular accumulation of amyloid peptide beta 42. J Neurochem 2010; 115:873-84. [PMID: 20412390 DOI: 10.1111/j.1471-4159.2010.06756.x] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Apolipoprotein E (apoE) plays a crucial role in lipid transport in circulation and the brain. The apoE4 isoform is a major risk factor for Alzheimer's disease (AD). ApoE4 is more susceptible to proteolysis than other apoE isoforms and apoE4 fragments have been found in brains of AD patients. These apoE4 fragments have been hypothesized to be involved in the pathogenesis of AD, although the mechanism is not clear. In this study we examined the effect of lipid-free apoE4 on amyloid precursor protein processing and 40-amino-acid Aβ variant and 42-amino-acid Aβ variant levels in human neuroblastoma SK-N-SH cells. We discovered that a specific apoE4 fragment, apoE4[Δ(166-299)], can promote the cellular uptake of extracellular 40-amino-acid Aβ variant and 42-amino-acid Aβ variant either generated after amyloid precursor protein transfection or added exogenously. A longer length fragment, apoE4[Δ(186-299)], or full-length apoE4 failed to elicit this effect. ApoE4[Δ(166-299)] effected a 20% reduction of cellular sphingomyelin levels, as well as changes in cellular membrane micro-fluidity. Following uptake, approximately 50% of 42-amino-acid Aβ variant remained within the cell for at least 24 h, and led to increased formation of reactive oxygen species. Overall, our findings suggest a direct link between two early events in the pathogenesis of AD, apoE4 proteolysis and intraneuronal presence of amyloid beta peptide.
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Affiliation(s)
- Ioannis Dafnis
- Institute of Biology, National Center for Scientific Research Demokritos, Athens, Greece
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