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Kimura T, Kimura AK, Ren M, Monteiro V, Xu Y, Berno B, Schlame M, Epand RM. Plasmalogen loss caused by remodeling deficiency in mitochondria. Life Sci Alliance 2019; 2:e201900348. [PMID: 31434794 PMCID: PMC6707388 DOI: 10.26508/lsa.201900348] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2019] [Revised: 07/30/2019] [Accepted: 08/01/2019] [Indexed: 12/16/2022] Open
Abstract
Lipid homeostasis is crucial in human health. Barth syndrome (BTHS), a life-threatening disease typically diagnosed with cardiomyopathy and neutropenia, is caused by mutations in the mitochondrial transacylase tafazzin. By high-resolution 31P nuclear magnetic resonance (NMR) with cryoprobe technology, recently we found a dramatic loss of choline plasmalogen in the tafazzin-knockdown (TAZ-KD) mouse heart, besides observing characteristic cardiolipin (CL) alterations in BTHS. In inner mitochondrial membrane where tafazzin locates, CL and diacyl phosphatidylethanolamine are known to be essential via lipid-protein interactions reflecting their cone shape for integrity of respiratory chain supercomplexes and cristae ultrastructure. Here, we investigate the TAZ-KD brain, liver, kidney, and lymphoblast from patients compared with controls. We identified common yet markedly cell type-dependent losses of ethanolamine plasmalogen as the dominant plasmalogen class therein. Tafazzin function thus critically relates to homeostasis of plasmalogen, which in the ethanolamine class has conceivably analogous and more potent molecular functions in mitochondria than diacyl phosphatidylethanolamine. The present discussion of a loss of plasmalogen-protein interaction applies to other diseases with mitochondrial plasmalogen loss and aberrant forms of this organelle, including Alzheimer's disease.
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Affiliation(s)
- Tomohiro Kimura
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Atsuko K Kimura
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Mindong Ren
- Department of Cell Biology, New York University Langone Medical Center, New York, NY, USA
- Department of Anesthesiology, New York University Langone Medical Center, New York, NY, USA
| | - Vernon Monteiro
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
| | - Yang Xu
- Department of Anesthesiology, New York University Langone Medical Center, New York, NY, USA
| | - Bob Berno
- Department of Chemistry and Chemical Biology, McMaster University, Hamilton, Canada
| | - Michael Schlame
- Department of Cell Biology, New York University Langone Medical Center, New York, NY, USA
- Department of Anesthesiology, New York University Langone Medical Center, New York, NY, USA
| | - Richard M Epand
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Canada
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Price JS, Emslie DJH, Berno B. Manganese Silyl Dihydride Complexes: A Spectroscopic, Crystallographic, and Computational Study of Nonclassical Silicate and Hydrosilane Hydride Isomers. Organometallics 2019. [DOI: 10.1021/acs.organomet.9b00179] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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Bozelli JC, Jennings W, Black S, Hou YH, Lameire D, Chatha P, Kimura T, Berno B, Khondker A, Rheinstädter MC, Epand RM. Membrane curvature allosterically regulates the phosphatidylinositol cycle, controlling its rate and acyl-chain composition of its lipid intermediates. J Biol Chem 2018; 293:17780-17791. [PMID: 30237168 DOI: 10.1074/jbc.ra118.005293] [Citation(s) in RCA: 35] [Impact Index Per Article: 5.8] [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: 08/10/2018] [Revised: 09/04/2018] [Indexed: 01/17/2023] Open
Abstract
Signaling events at membranes are often mediated by membrane lipid composition or membrane physical properties. These membrane properties could act either by favoring the membrane binding of downstream effectors or by modulating their activity. Several proteins can sense/generate membrane physical curvature (i.e. shape). However, the modulation of the activity of enzymes by a membrane's shape has not yet been reported. Here, using a cell-free assay with purified diacylglycerol kinase ϵ (DGKϵ) and liposomes, we studied the activity and acyl-chain specificity of an enzyme of the phosphatidylinositol (PI) cycle, DGKϵ. By systematically varying the model membrane lipid composition and physical properties, we found that DGKϵ has low activity and lacks acyl-chain specificity in locally flat membranes, regardless of the lipid composition. On the other hand, these enzyme properties were greatly enhanced in membrane structures with a negative Gaussian curvature. We also found that this is not a consequence of preferential binding of the enzyme to those structures, but rather is due to a curvature-mediated allosteric regulation of DGKϵ activity and acyl-chain specificity. Moreover, in a fine-tuned interplay between the enzyme and the membrane, DGKϵ favored the formation of structures with greater Gaussian curvature. DGKϵ does not bear a regulatory domain, and these findings reveal the importance of membrane curvature in regulating DGKϵ activity and acyl-chain specificity. Hence, this study highlights that a hierarchic coupling of membrane physical property and lipid composition synergistically regulates membrane signaling events. We propose that this regulatory mechanism of membrane-associated enzyme activity is likely more common than is currently appreciated.
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Affiliation(s)
- José Carlos Bozelli
- From the Department of Biochemistry and Biomedical Sciences, Health Sciences Centre, McMaster University, Hamilton, Ontario L8S 4K1
| | - William Jennings
- From the Department of Biochemistry and Biomedical Sciences, Health Sciences Centre, McMaster University, Hamilton, Ontario L8S 4K1
| | - Stephanie Black
- From the Department of Biochemistry and Biomedical Sciences, Health Sciences Centre, McMaster University, Hamilton, Ontario L8S 4K1
| | - Yu Heng Hou
- From the Department of Biochemistry and Biomedical Sciences, Health Sciences Centre, McMaster University, Hamilton, Ontario L8S 4K1
| | - Darius Lameire
- From the Department of Biochemistry and Biomedical Sciences, Health Sciences Centre, McMaster University, Hamilton, Ontario L8S 4K1
| | - Preet Chatha
- From the Department of Biochemistry and Biomedical Sciences, Health Sciences Centre, McMaster University, Hamilton, Ontario L8S 4K1
| | - Tomohiro Kimura
- From the Department of Biochemistry and Biomedical Sciences, Health Sciences Centre, McMaster University, Hamilton, Ontario L8S 4K1
| | | | - Adree Khondker
- Physics and Astronomy; Origins Institute, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Maikel C Rheinstädter
- Physics and Astronomy; Origins Institute, McMaster University, Hamilton, Ontario L8S 4L8, Canada
| | - Richard M Epand
- From the Department of Biochemistry and Biomedical Sciences, Health Sciences Centre, McMaster University, Hamilton, Ontario L8S 4K1; Departments of Chemistry.
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Abstract
Tafazzin is the mitochondrial enzyme that catalyzes transacylation between a phospholipid and a lysophospholipid in remodeling. Mutations in tafazzin cause Barth syndrome, a potentially life-threatening disease with the major symptom being cardiomyopathy. In the tafazzin-deficient heart, cardiolipin (CL) acyl chains become abnormally heterogeneous unlike those in the normal heart with a single dominant linoleoyl species, tetralinoleoyl CL. In addition, the amount of CL decreases and monolysocardiolipin (MLCL) accumulates. Here we determine using high-resolution 31P nuclear magnetic resonance with cryoprobe technology the fundamental phospholipid composition, including the major but oxidation-labile plasmalogens, in the tafazzin-knockdown (TAZ-KD) mouse heart as a model of Barth syndrome. In addition to confirming a lower level of CL (6.4 ± 0.1 → 2.0 ± 0.4 mol % of the total phospholipid) and accumulation of MLCL (not detected → 3.3 ± 0.5 mol %) in the TAZ-KD, we found a substantial reduction in the level of plasmenylcholine (30.8 ± 2.8 → 18.1 ± 3.1 mol %), the most abundant phospholipid in the control wild type. A quantitative Western blot revealed that while the level of peroxisomes, where early steps of plasmalogen synthesis take place, was normal in the TAZ-KD model, expression of Far1 as a rate-determining enzyme in plasmalogen synthesis was dramatically upregulated by 8.3 (±1.6)-fold to accelerate the synthesis in response to the reduced level of plasmalogen. We confirmed lyso-plasmenylcholine or plasmenylcholine is a substrate of purified tafazzin for transacylation with CL or MLCL, respectively. Our results suggest that plasmenylcholine, abundant in linoleoyl species, is important in remodeling CL in the heart. Tafazzin deficiency thus has a major impact on the cardiac plasmenylcholine level and thereby its functions.
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Affiliation(s)
- Tomohiro Kimura
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Atsuko K. Kimura
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Mindong Ren
- Department of Cell Biology, NYU Langone Medical Center, New York, NY 10016
| | - Bob Berno
- Department of Chemistry, McMaster University, Hamilton, ON L8S 4K1, Canada
| | - Yang Xu
- Department of Anesthesiology, NYU Langone Medical Center, New York, NY 10016
| | - Michael Schlame
- Department of Cell Biology, NYU Langone Medical Center, New York, NY 10016
- Department of Anesthesiology, NYU Langone Medical Center, New York, NY 10016
| | - Richard M. Epand
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, ON L8S 4K1, Canada
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5
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Abstract
Introducing a gelling step during antibiotic incorporation has previously been found to delay vancomycin delivery from a calcium polyphosphate matrix intended for local treatment of bone infections. This study examined the general applicability of this approach using cefuroxime, a lower-molecular-weight antibiotic with different charge characteristics compared with those of vancomycin. A calcium polyphosphate/cefuroxime paste was “gelled” in disk form in a humid environment for 5 or 24 hours prior to drying. Antibiotic release in Tris-buffered saline under gentle agitation was monitored over a seven-day period. While non-gelled samples clearly exhibited a burst release, the gelling process significantly retarded early antibiotic release from five- and 24-hour gelled matrices, yielding a constant release rate over the first four days. Cefuroxime incorporation did not appear to alter matrix structure or degradation. Overall, this non-aggressive process effectively trapped cefuroxime and reduced its release rate, suggesting its potential applicability with molecularly diverse therapeutic agents.
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Affiliation(s)
- S C Schofield
- Department of Applied Oral Sciences, Faculty of Dentistry, Dalhousie University, 5981 University Avenue, Halifax, Nova Scotia B3H 3J5, Canada
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Xu Y, Phoon CKL, Berno B, D'Souza K, Hoedt E, Zhang G, Neubert TA, Epand RM, Ren M, Schlame M. Loss of protein association causes cardiolipin degradation in Barth syndrome. Nat Chem Biol 2016; 12:641-7. [PMID: 27348092 PMCID: PMC4955704 DOI: 10.1038/nchembio.2113] [Citation(s) in RCA: 87] [Impact Index Per Article: 10.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2015] [Accepted: 04/18/2016] [Indexed: 12/25/2022]
Abstract
Cardiolipin is a specific mitochondrial phospholipid that has a high affinity for proteins and that stabilizes the assembly of supercomplexes involved in oxidative phosphorylation. We found that sequestration of cardiolipin in protein complexes is critical to protect it from degradation. The turnover of cardiolipin is slower by almost an order of magnitude than the turnover of other phospholipids. However, in subjects with Barth syndrome, cardiolipin is rapidly degraded via the intermediate monolyso-cardiolipin. Treatments that induce supercomplex assembly decrease the turnover of cardiolipin and the concentration of monolyso-cardiolipin, whereas dissociation of supercomplexes has the opposite effect. Our data suggest that cardiolipin is uniquely protected from normal lipid turnover by its association with proteins, but this association is compromised in subjects with Barth syndrome, leading cardiolipin to become unstable, which in turn causes the accumulation of monolyso-cardiolipin.
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Affiliation(s)
- Yang Xu
- Department of Anesthesiology, New York University School of Medicine, New York, New York, USA
| | - Colin K L Phoon
- Department of Pediatrics, New York University School of Medicine, New York, New York, USA
| | - Bob Berno
- Department of Chemistry, McMaster University, Hamilton, Ontario, Canada
| | - Kenneth D'Souza
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Esthelle Hoedt
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, New York, USA.,Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Guoan Zhang
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, New York, USA.,Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Thomas A Neubert
- Kimmel Center for Biology and Medicine at the Skirball Institute, New York University School of Medicine, New York, New York, USA.,Department of Biochemistry and Molecular Pharmacology, New York University School of Medicine, New York, New York, USA
| | - Richard M Epand
- Department of Chemistry, McMaster University, Hamilton, Ontario, Canada.,Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, Ontario, Canada
| | - Mindong Ren
- Department of Anesthesiology, New York University School of Medicine, New York, New York, USA.,Department of Cell Biology, New York University School of Medicine, New York, New York, USA
| | - Michael Schlame
- Department of Anesthesiology, New York University School of Medicine, New York, New York, USA.,Department of Cell Biology, New York University School of Medicine, New York, New York, USA
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Epand RM, Prodeus A, Berno B, Topham MK. The Basis of the Substrate Specificity of the Epsilon Isoform of Human Diacylglycerol Kinase is not a Consequence of Competing Hydrolysis of ATP. FASEB J 2013. [DOI: 10.1096/fasebj.27.1_supplement.1018.2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Richard M. Epand
- Biochemistry and Biomedical Sci.McMaster UniversityHamiltonONCanada
| | - Aaron Prodeus
- Biochemistry and Biomedical Sci.McMaster UniversityHamiltonONCanada
| | - Bob Berno
- Chemistry and Chemical BiologyMcMaster UniversityHamiltonONCanada
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8
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Schlame M, Acehan D, Berno B, Xu Y, Valvo S, Ren M, Stokes DL, Epand RM. The physical state of lipid substrates provides transacylation specificity for tafazzin. Nat Chem Biol 2013; 8:862-9. [PMID: 22941046 DOI: 10.1038/nchembio.1064] [Citation(s) in RCA: 94] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2012] [Accepted: 08/09/2012] [Indexed: 11/09/2022]
Abstract
Cardiolipin is a mitochondrial phospholipid with a characteristic acyl chain composition that depends on the function of tafazzin, a phospholipid-lysophospholipid transacylase, although the enzyme itself lacks acyl specificity. We incubated isolated tafazzin with various mixtures of phospholipids and lysophospholipids, characterized the lipid phase by (31)P-NMR and measured newly formed molecular species by MS. Substantial transacylation was observed only in nonbilayer lipid aggregates, and the substrate specificity was highly sensitive to the lipid phase. In particular, tetralinoleoyl-cardiolipin, a prototype molecular species, formed only under conditions that favor the inverted hexagonal phase. In isolated mitochondria, <1% of lipids participated in transacylations, suggesting that the action of tafazzin was limited to privileged lipid domains. We propose that tafazzin reacts with non-bilayer-type lipid domains that occur in curved or hemifused membrane zones and that acyl specificity is driven by the packing properties of these domains.
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Affiliation(s)
- Michael Schlame
- Department of Anesthesiology, New York University School of Medicine, New York, NY, USA.
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9
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Hartman JS, Berno B, Hazendonk P, Hens P, Ye E, Bain AD. Spin-lattice relaxation in aluminum-doped semiconducting 4H and 6H polytypes of silicon carbide. Solid State Nucl Magn Reson 2012; 45-46:45-50. [PMID: 22727848 DOI: 10.1016/j.ssnmr.2012.05.003] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/20/2012] [Revised: 05/29/2012] [Accepted: 05/30/2012] [Indexed: 06/01/2023]
Abstract
NMR spin-lattice relaxation efficiency is similar at all carbon and silicon sites in aluminum-doped 4H- and 6H-polytype silicon carbide samples, indicating that the valence band edge (the top of the valence band), where the holes are located in p-doped materials, has similar charge densities at all atomic sites. This is in marked contrast to nitrogen-doped samples of the same polytypes where huge site-specific differences in relaxation efficiency indicate that the conduction band edge (the bottom of the conduction band), where the mobile electrons are located in n-doped materials, has very different charge densities at the different sites. An attempt was made to observe (27)Al NMR signals directly, but they are too broad, due to paramagnetic line broadening, to provide useful information about aluminum doping.
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Affiliation(s)
- J Stephen Hartman
- Department of Chemistry, Brock University, St. Catharines, Ontario, Canada.
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10
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Schlame M, Acehan D, Berno B, Xu Y, Ren M, Stokes DL, Epand RM. Reconstitution of Acyl Specific Phospholipid Remodeling by Purified Tafazzin In Vitro. Biophys J 2012. [DOI: 10.1016/j.bpj.2011.11.1599] [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] [Subscribe] [Scholar Register] [Indexed: 11/25/2022] Open
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11
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Bain AD, Berno B. Liouvillians in NMR: the direct method revisited. Prog Nucl Magn Reson Spectrosc 2011; 59:223-244. [PMID: 21920219 DOI: 10.1016/j.pnmrs.2010.12.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/11/2010] [Accepted: 12/16/2010] [Indexed: 05/31/2023]
Affiliation(s)
- Alex D Bain
- Department of Chemistry and Chemical Biology, McMaster University 1280 Main St., West Hamilton, Ontario, Canada L8S 4M1.
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12
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Epand RM, Epand RF, Berno B, Pelosi L, Brandolin G. Association of phosphatidic acid with the bovine mitochondrial ADP/ATP carrier. Biochemistry 2010; 48:12358-64. [PMID: 19902971 DOI: 10.1021/bi901769r] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
The beef heart adenine nucleotide carrier protein (Anc) of the inner mitochondrial membrane can be purified in a form stabilized by binding the inhibitor carboxyatractyloside. The protein is copurified with bound lipid. We show for the first time that phosphatidic acid, although a minor component, is one of the lipids bound to Anc. The short spin-lattice relaxation time found by (31)P magic angle spinning nuclear magnetic resonance (MAS/NMR) for phosphatidic acid indicates that it is tightly bound to the protein. However, this lipid also has a comparatively small chemical shift anisotropy, suggesting that it can undergo rapid reorientation in space. In contrast, most of the lipid bound to Anc shows anisotropic motion typical of a bilayer arrangement. The phosphatidic acid that is detected in the purified preparation of Anc is also shown to be present initially in the unfractionated mitochondria, prior to the isolation of Anc. In Triton-solubilized mitochondria, phosphatidic acid, cardiolipin, phosphatidylethanolamine, and phosphatidylcholine exhibit resonance lines in the static (31)P NMR spectra, but in the purified Anc, only the phosphatidylethanolamine and phosphatidylcholine can be detected by this method, even though the other lipids are still present. This demonstrates that the phosphatidic acid and cardiolipin are interacting with the Anc. The thermal denaturation of the Anc was determined by differential scanning calorimetry. The protein denatures at 74 degrees C both before and after the NMR studies with the same characteristics.
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Affiliation(s)
- Richard M Epand
- Department of Biochemistry and Biomedical Sciences, McMaster University, Hamilton, OntarioL8N 3Z5, Canada.
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13
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Epand RM, Epand RF, Berno B, Pelosi L, Brandolin G. Phosphatidic Acid Association with the Bovine Mitochondrial ADP/ATP Carrier. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.2753] [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] [Subscribe] [Scholar Register] [Indexed: 10/19/2022] Open
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14
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Epand RM, Rotem S, Mor A, Berno B, Epand RF. Lipid Domains in Bacterial Membranes as a Predictor of Antimicrobial Potency. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.2312] [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] [Subscribe] [Scholar Register] [Indexed: 10/21/2022] Open
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15
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Affiliation(s)
- Richard M. Epand
- Departments of Biochemistry and Biomedical Sciences and of Chemistry, McMaster University, Hamilton, Ontario L8N 3Z5, Canada, and Department of Biotechnology & Food Engineering, Technion—Israel Institute of Technology, Haifa 32000, Israel
| | - Shahar Rotem
- Departments of Biochemistry and Biomedical Sciences and of Chemistry, McMaster University, Hamilton, Ontario L8N 3Z5, Canada, and Department of Biotechnology & Food Engineering, Technion—Israel Institute of Technology, Haifa 32000, Israel
| | - Amram Mor
- Departments of Biochemistry and Biomedical Sciences and of Chemistry, McMaster University, Hamilton, Ontario L8N 3Z5, Canada, and Department of Biotechnology & Food Engineering, Technion—Israel Institute of Technology, Haifa 32000, Israel
| | - Bob Berno
- Departments of Biochemistry and Biomedical Sciences and of Chemistry, McMaster University, Hamilton, Ontario L8N 3Z5, Canada, and Department of Biotechnology & Food Engineering, Technion—Israel Institute of Technology, Haifa 32000, Israel
| | - Raquel F. Epand
- Departments of Biochemistry and Biomedical Sciences and of Chemistry, McMaster University, Hamilton, Ontario L8N 3Z5, Canada, and Department of Biotechnology & Food Engineering, Technion—Israel Institute of Technology, Haifa 32000, Israel
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16
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Handattu SP, Garber DW, Horn DC, Hughes DW, Berno B, Bain AD, Mishra VK, Palgunachari MN, Datta G, Anantharamaiah GM, Epand RM. ApoA-I mimetic peptides with differing ability to inhibit atherosclerosis also exhibit differences in their interactions with membrane bilayers. J Biol Chem 2006; 282:1980-8. [PMID: 17114186 DOI: 10.1074/jbc.m606231200] [Citation(s) in RCA: 33] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Two homologous apoA-I mimetic peptides, 3F-2 and 3F(14), differ in their in vitro antiatherogenic properties (Epand, R. M., Epand, R. F., Sayer, B. G., Datta, G., Chaddha, M., and Anantharamaiah, G. M. (2004) J. Biol. Chem. 279, 51404-51414). In the present work, we demonstrate that the peptide 3F-2, which has more potent anti-inflammatory activity in vitro when administered intraperitoneally to female apoE null mice (20 microg/mouse/day) for 6 weeks, inhibits atherosclerosis (lesion area 15,800 +/- 1000 microm(2), n = 29), whereas 3F(14) does not (lesion area 20,400 +/- 1000 microm(2), n = 26) compared with control saline administered (19,900 +/- 1400 microm(2), n = 22). Plasma distribution of the peptides differs in that 3F-2 preferentially associates with high density lipoprotein, whereas 3F(14) preferentially associates with apoB-containing particles. After intraperitoneal injection of (14)C-labeled peptides, 3F(14) reaches a higher maximal concentration and has a longer half-time of elimination than 3F-2. A study of the effect of these peptides on the motional and organizational properties of phospholipid bilayers, using several NMR methods, demonstrates that the two peptides insert to different extents into membranes. 3F-2 with aromatic residues at the center of the nonpolar face partitions closer to the phospholipid head group compared with 3F(14). In contrast, only 3F(14) affects the terminal methyl group of the acyl chain, decreasing the (2)H order parameter and at the same time also decreasing the molecular motion of this methyl group. This dual effect of 3F(14) can be explained in terms of the cross-sectional shape of the amphipathic helix. These results support the proposal that the molecular basis for the difference in the biological activities of the two peptides lies with their different interactions with membranes.
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Affiliation(s)
- Shaila P Handattu
- Department of Medicine, University of Alabama at Birmingham, Birmingham, Alabama 35294, USA
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Abstract
A variety of dipyrromethanes and dipyrromethenes have been prepared, and their 15N NMR chemical shifts have been measured by two-dimensional correlation to 1H NMR signals. The nitrogen atoms in five examples of dipyrromethanes consistently exhibit chemical shifts around -231 ppm, relative to nitromethane. Seven examples of hydrobromide salts of meso-unsubstituted dipyrromethenes consistently display 15N chemical shifts around -210 ppm, while their corresponding zinc(II) complexes exhibit chemical shifts around -170 ppm. The presence of electron-withdrawing substituents on one of the pyrrolic rings of dipyrromethenes affects the chemical shifts of both of the nitrogen nuclei in the molecule. Boron difluoride complexes of meso-unsubstituted dipyrromethenes display 15N chemical shifts around -190 ppm. Two examples of free-base dipyrromethenes bearing substituents at the meso-position exhibit 15N chemical shifts at approximately -156 ppm, and for the zinc complexes of these compounds at -162 ppm. One-bond nitrogen-hydrogen coupling constants, when measurable, were consistently in the range of -96 Hz. Since the measured 15N chemical shifts have such a high regularity correlated to structure, they can be used as diagnostic indications for identifying the structure of dipyrrolic compounds.
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Affiliation(s)
- Tabitha E Wood
- Department of Chemistry, Dalhousie University, Halifax, Nova Scotia, Canada, B3H 4J3
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18
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Dion A, Berno B, Hall G, Filiaggi MJ. The effect of processing on the structural characteristics of vancomycin-loaded amorphous calcium phosphate matrices. Biomaterials 2005; 26:4486-94. [PMID: 15701378 DOI: 10.1016/j.biomaterials.2004.11.010] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2004] [Accepted: 11/09/2004] [Indexed: 10/26/2022]
Abstract
Calcium polyphosphate antibiotic delivery matrices were prepared using a unique processing technique involving the exposure of calcium polyphosphate pastes to high humidity for 0, 5, 24 or 48 h to induce gelling. Subsequently, samples were dried for a minimum of 24 h. The mild conditions associated with matrix fabrication readily allowed for vancomycin incorporation within an environment that did not disrupt antibiotic activity. While reproducible from a processing standpoint, the gelling and drying process did contribute to a decrease in matrix tensile strength and the formation of significant pores near the surface of the matrices. Generally, the core of the gelled matrices appeared to be denser than their non-gelled counterparts. The degree of phosphate chain lysis during the gelling and drying stages was quantified using solution 31P nuclear magnetic resonance (NMR) spectroscopy. Both NMR and Raman spectroscopy indicated that the presence of vancomycin did not appreciably alter the matrix formation process. The ability to incorporate clinically relevant levels of antibiotic within this degradable bone substitute matrix suggests the potential of this approach for creating a localized antibiotic delivery system to treat osteomyelitis infections.
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Affiliation(s)
- Anna Dion
- School of Biomedical Engineering, Dalhousie University, Halifax, Nova Scotia, Canada B3H 3J5
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