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Gooran N, Tan SW, Frey SL, Jackman JA. Unraveling the Biophysical Mechanisms of How Antiviral Detergents Disrupt Supported Lipid Membranes: Toward Replacing Triton X-100. Langmuir 2024; 40:6524-6536. [PMID: 38478717 DOI: 10.1021/acs.langmuir.4c00174] [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] [Indexed: 03/27/2024]
Abstract
Triton X-100 (TX-100) is a membrane-disrupting detergent that is widely used to inactivate membrane-enveloped viral pathogens, yet is being phased out due to environmental safety concerns. Intense efforts are underway to discover regulatory acceptable detergents to replace TX-100, but there is scarce mechanistic understanding about how these other detergents disrupt phospholipid membranes and hence which ones are suitable to replace TX-100 from a biophysical interaction perspective. Herein, using the quartz crystal microbalance-dissipation (QCM-D) and electrochemical impedance spectroscopy (EIS) techniques in combination with supported lipid membrane platforms, we characterized the membrane-disruptive properties of a panel of TX-100 replacement candidates with varying antiviral activities and identified two distinct classes of membrane-interacting detergents with different critical micelle concentration (CMC) dependencies and biophysical mechanisms. While all tested detergents formed micelles, only a subset of the detergents caused CMC-dependent membrane solubilization similarly to that of TX-100, whereas other detergents adsorbed irreversibly to lipid membrane interfaces in a CMC-independent manner. We compared these biophysical results to virus inactivation data, which led us to identify that certain membrane-interaction profiles contribute to greater antiviral activity and such insights can help with the discovery and validation of antiviral detergents to replace TX-100.
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Affiliation(s)
- Negin Gooran
- School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Sue Woon Tan
- School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Shelli L Frey
- School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
- Department of Chemistry, Gettysburg College, Gettysburg, Pennsylvania 17325, United States
| | - Joshua A Jackman
- School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
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2
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Skeens A, Siriwardhana C, Massinople SE, Wunder MM, Ellis ZL, Keith KM, Girman T, Frey SL, Legleiter J. The polyglutamine domain is the primary driver of seeding in huntingtin aggregation. PLoS One 2024; 19:e0298323. [PMID: 38483973 PMCID: PMC10939245 DOI: 10.1371/journal.pone.0298323] [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] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 01/22/2024] [Indexed: 03/17/2024] Open
Abstract
Huntington's Disease (HD) is a fatal, neurodegenerative disease caused by aggregation of the huntingtin protein (htt) with an expanded polyglutamine (polyQ) domain into amyloid fibrils. Htt aggregation is modified by flanking sequences surrounding the polyQ domain as well as the binding of htt to lipid membranes. Upon fibrillization, htt fibrils are able to template the aggregation of monomers into fibrils in a phenomenon known as seeding, and this process appears to play a critical role in cell-to-cell spread of HD. Here, exposure of C. elegans expressing a nonpathogenic N-terminal htt fragment (15-repeat glutamine residues) to preformed htt-exon1 fibrils induced inclusion formation and resulted in decreased viability in a dose dependent manner, demonstrating that seeding can induce toxic aggregation of nonpathogenic forms of htt. To better understand this seeding process, the impact of flanking sequences adjacent to the polyQ stretch, polyQ length, and the presence of model lipid membranes on htt seeding was investigated. Htt seeding readily occurred across polyQ lengths and was independent of flanking sequence, suggesting that the structured polyQ domain within fibrils is the key contributor to the seeding phenomenon. However, the addition of lipid vesicles modified seeding efficiency in a manner suggesting that seeding primarily occurs in bulk solution and not at the membrane interface. In addition, fibrils formed in the presence of lipid membranes displayed similar seeding efficiencies. Collectively, this suggests that the polyQ domain that forms the amyloid fibril core is the main driver of seeding in htt aggregation.
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Affiliation(s)
- Adam Skeens
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Chathuranga Siriwardhana
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Sophia E. Massinople
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Michelle M. Wunder
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Zachary L. Ellis
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Kaitlyn M. Keith
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Tyler Girman
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
| | - Shelli L. Frey
- The Department of Chemistry, Gettysburg College, Gettysburg, Pennsylvania, United States of America
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia, United States of America
- Rockefeller Neurosciences Institutes, West Virginia University, Morgantown, West Virginia, United States of America
- Department of Neuroscience, West Virginia University, Morgantown, West Virginia, United States of America
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3
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Markle J, Frey SL. Interaction of the huntingtin N-terminal sequence with model cell membranes. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.2312] [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: 11/26/2022] Open
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4
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Reitz A, Frey SL. Effects of charge on the interaction of the huntingtin N-terminal sequence with model cell membranes. Biophys J 2022. [DOI: 10.1016/j.bpj.2021.11.2311] [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: 11/02/2022] Open
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5
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Andresen K, Peduzzi O, Woodward C, Madore K, Frey SL, Buettner KM. Irreversibility of Conformational Changes and ZN2+Binding to DNA. Biophys J 2020. [DOI: 10.1016/j.bpj.2019.11.1308] [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: 10/25/2022] Open
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Abstract
We experimentally investigate the effect of lipid charge on the stiffness of bilayer membranes. The bending rigidity of membranes with composition 0-100 mol% of charged lipids, in the absence and presence of salt at different concentrations, is measured with the flicker spectroscopy method, using the shape fluctuations of giant unilamellar vesicles. The analysis considers both the mean squared amplitudes and the time autocorrelations of the shape modes. Our results show that membrane charge increases the bending rigidity relative to the charge-free membrane. The effect is diminished by the addition of monovalent salt to the suspending solutions. The trend shown by the membrane bending rigidity correlates with zeta potential measurements, confirming charge screening at different salt concentrations. The experimental results in the presence of salt are in good agreement with existing theories of membrane stiffening by surface charge.
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Affiliation(s)
- Hammad A Faizi
- Department of Mechanical Engineering, McCormick School of Engineering and Applied Science, Northwestern University, Evanston, Illinois 60208, USA
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7
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Campbell WA, Chaibva M, Gao X, Zhao Z, Legleiter J, Frey SL. Measuring the Interaction of Polyglutamine Peptides with Lipid Membranes. Biophys J 2019. [DOI: 10.1016/j.bpj.2018.11.151] [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: 11/15/2022] Open
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8
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Counihan MJ, Frey SL. Lateral Phase Behavior of Human Skin Lipids. Biophys J 2018. [DOI: 10.1016/j.bpj.2017.11.602] [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: 10/18/2022] Open
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Chaibva M, Gao X, Jain P, Campbell WA, Frey SL, Legleiter J. Sphingomyelin and GM1 Influence Huntingtin Binding to, Disruption of, and Aggregation on Lipid Membranes. ACS Omega 2018; 3:273-285. [PMID: 29399649 PMCID: PMC5793032 DOI: 10.1021/acsomega.7b01472] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Accepted: 12/25/2017] [Indexed: 05/09/2023]
Abstract
Huntington disease (HD) is an inherited neurodegenerative disease caused by the expansion beyond a critical threshold of a polyglutamine (polyQ) tract near the N-terminus of the huntingtin (htt) protein. Expanded polyQ promotes the formation of a variety of oligomeric and fibrillar aggregates of htt that accumulate into the hallmark proteinaceous inclusion bodies associated with HD. htt is also highly associated with numerous cellular and subcellular membranes that contain a variety of lipids. As lipid homeostasis and metabolism abnormalities are observed in HD patients, we investigated how varying both the sphingomyelin (SM) and ganglioside (GM1) contents modifies the interactions between htt and lipid membranes. SM composition is altered in HD, and GM1 has been shown to have protective effects in animal models of HD. A combination of Langmuir trough monolayer techniques, vesicle permeability and binding assays, and in situ atomic force microscopy (AFM) were used to directly monitor the interaction of a model, synthetic htt peptide and a full-length htt-exon1 recombinant protein with model membranes comprised of total brain lipid extract (TBLE) and varying amounts of exogenously added SM or GM1. The addition of either SM or GM1 decreased htt insertion into the lipid monolayers. However, TBLE vesicles with an increased SM content were more susceptible to htt-induced permeabilization, whereas GM1 had no effect on permeablization. Pure TBLE bilayers and TBLE bilayers enriched with GM1 developed regions of roughened, granular morphologies upon exposure to htt-exon1, but plateau-like domains with a smoother appearance formed in bilayers enriched with SM. Oligomeric aggregates were observed on all bilayer systems regardless of induced morphology. Collectively, these observations suggest that the lipid composition and its subsequent effects on membrane material properties strongly influence htt binding and aggregation on lipid membranes.
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Affiliation(s)
- Maxmore Chaibva
- The
C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, P.O. Box 6045, Morgantown, West Virginia 26505, United States
| | - Xiang Gao
- The
C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, P.O. Box 6045, Morgantown, West Virginia 26505, United States
| | - Pranav Jain
- The
C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, P.O. Box 6045, Morgantown, West Virginia 26505, United States
| | - Warren A. Campbell
- Department
of Chemistry, Gettysburg College, 300 N. Washington Avenue, Campus Box 0393, Gettysburg, Pennsylvania 17325, United States
| | - Shelli L. Frey
- Department
of Chemistry, Gettysburg College, 300 N. Washington Avenue, Campus Box 0393, Gettysburg, Pennsylvania 17325, United States
- E-mail: . Phone: 717-337-6259 (S.L.F.)
| | - Justin Legleiter
- The
C. Eugene Bennett Department of Chemistry, West Virginia University, 217 Clark Hall, P.O. Box 6045, Morgantown, West Virginia 26505, United States
- Blanchette
Rockefeller Neurosciences Institutes, West
Virginia University, 1 Medical Center Dr., P.O. Box 9303, Morgantown, West Virginia 26505, United States
- E-mail: . Phone: 304-293-0175 (J.L.)
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Campbell WA, Chaibva M, Gao X, Legleiter J, Frey SL. The Role of Sphingomyelin and Ganglioside GM1 in the Interaction of Polyglutamine Peptides with Lipid Membranes. Biophys J 2017. [DOI: 10.1016/j.bpj.2016.11.1265] [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: 10/20/2022] Open
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11
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Counihan MJ, Frey SL. Lateral Phase Behavior of Human Skin Lipids. Biophys J 2016. [DOI: 10.1016/j.bpj.2015.11.449] [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: 11/24/2022] Open
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13
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Gao X, Campbell WA, Chaibva M, Jain P, Leslie AE, Frey SL, Legleiter J. Cholesterol Modifies Huntingtin Binding to, Disruption of, and Aggregation on Lipid Membranes. Biochemistry 2015; 55:92-102. [PMID: 26652744 DOI: 10.1021/acs.biochem.5b00900] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Huntington's disease (HD) is an inherited neurodegenerative disease caused by abnormally long CAG-repeats in the huntingtin gene that encode an expanded polyglutamine (polyQ) domain near the N-terminus of the huntingtin (htt) protein. Expanded polyQ domains are directly correlated to disease-related htt aggregation. Htt is found highly associated with a variety of cellular and subcellular membranes that are predominantly comprised of lipids. Since cholesterol homeostasis is altered in HD, we investigated how varying cholesterol content modifies the interactions between htt and lipid membranes. A combination of Langmuir trough monolayer techniques, vesicle permeability and binding assays, and in situ atomic force microscopy were used to directly monitor the interaction of a model, synthetic htt peptide and a full-length htt-exon1 recombinant protein with model membranes comprised of total brain lipid extract (TBLE) and varying amounts of exogenously added cholesterol. As the cholesterol content of the membrane increased, the extent of htt insertion decreased. Vesicles containing extra cholesterol were resistant to htt-induced permeabilization. Morphological and mechanical changes in the bilayer associated with exposure to htt were also drastically altered by the presence of cholesterol. Disrupted regions of pure TBLE bilayers were grainy in appearance and associated with a large number of globular aggregates. In contrast, morphological changes induced by htt in bilayers enriched in cholesterol were plateau-like with a smooth appearance. Collectively, these observations suggest that the presence and amount of cholesterol in lipid membranes play a critical role in htt binding and aggregation on lipid membranes.
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Affiliation(s)
- Xiang Gao
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26505, United States
| | - Warren A Campbell
- Department of Chemistry, Gettysburg College, Gettysburg, Pennsylvania 17325, United States
| | - Maxmore Chaibva
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26505, United States
| | - Pranav Jain
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26505, United States
| | - Ashley E Leslie
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26505, United States
| | - Shelli L Frey
- Department of Chemistry, Gettysburg College, Gettysburg, Pennsylvania 17325, United States
| | - Justin Legleiter
- The C. Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26505, United States.,NanoSAFE, P.O. Box 6223, West Virginia University, Morgantown, West Virginia 26506, United States.,The Center for Neurosciences, West Virginia University, Morgantown, West Virginia 26505, United States
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Frey SL, Todd J, Wurtzler E, Strelez CR, Wendell D. A non-foaming proteosurfactant engineered from Ranaspumin-2. Colloids Surf B Biointerfaces 2015; 133:239-45. [PMID: 26117804 DOI: 10.1016/j.colsurfb.2015.05.043] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2015] [Revised: 05/20/2015] [Accepted: 05/22/2015] [Indexed: 11/20/2022]
Abstract
Advances in biological surfactant proteins have already yielded a diverse range of benefits from dramatically improved survival rates for premature births to artificial photosynthesis. Presented here is the design, development, and analysis of a novel biosurfactant protein we call Surfactant Resisting Foam formatioN (SRFN). Starting with the Tungara frog's foam forming protein Ranaspumin-2, we have engineered a new surfactant protein with a destabilized hinge region to alter the kinetics and equilibrium of the protein structural transition from aqueous globular form to an extended surfactant structure at the air/water interface. SRFN is capable of approximately the same total surface tension reduction, but with the unique property of forming quickly collapsible foams. The difference in foam formation is attributed to the destabilizing glycine substitutions engineered into the hinge region. Surfactants used specifically to increase wettability, such as those used in agricultural applications would benefit from this new proteosurfactant since foamed liquid has greater wind resistance and decreased dispersal. Indeed, given growing concern of organsilicone surfactant effects on declining bee populations, biological surfactant proteins have several unique advantages over more common amphiphiles in that they can be renewably sourced, are environmentally friendly, degrade readily into non-toxic byproducts, and reduce surface tension without deleterious effects on cell membranes.
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Affiliation(s)
- Shelli L Frey
- Department of Chemistry, Gettysburg College, Gettysburg, PA 17325, United States
| | - Jacob Todd
- Department of Biomedical, Chemical and Environmental Engineering, Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221, United States
| | - Elizabeth Wurtzler
- Department of Biomedical, Chemical and Environmental Engineering, Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221, United States
| | - Carly R Strelez
- Department of Chemistry, Gettysburg College, Gettysburg, PA 17325, United States
| | - David Wendell
- Department of Biomedical, Chemical and Environmental Engineering, Engineering Research Center, University of Cincinnati, Cincinnati, OH 45221, United States.
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15
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Van Doren D, Cuculis L, Frey SL. Polystyrene Nanoparticles Alter the Stability of Model Cell Membranes. Biophys J 2015. [DOI: 10.1016/j.bpj.2014.11.2987] [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: 10/24/2022] Open
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16
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Campbell WA, Van Doren D, Burke KA, Legleiter J, Frey SL. The Role of Protein and Membrane Context in the Interaction of Polyglutamine Peptides with Lipid Membranes. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.1452] [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: 10/23/2022] Open
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17
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Strelez CR, Wendell D, Frey SL. Determining Surface Activity and Membrane Interactions of Ranaspumin-2 and an Engineered Derivative, Surfactant Resisting Foam Formation. Biophys J 2014. [DOI: 10.1016/j.bpj.2013.11.2375] [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: 11/16/2022] Open
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18
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Burke KA, Kauffman KJ, Umbaugh CS, Frey SL, Legleiter J. The interaction of polyglutamine peptides with lipid membranes is regulated by flanking sequences associated with huntingtin. J Biol Chem 2013; 288:14993-5005. [PMID: 23572526 DOI: 10.1074/jbc.m112.446237] [Citation(s) in RCA: 69] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022] Open
Abstract
Huntington disease (HD) is caused by an expanded polyglutamine (poly(Q)) repeat near the N terminus of the huntingtin (htt) protein. Expanded poly(Q) facilitates formation of htt aggregates, eventually leading to deposition of cytoplasmic and intranuclear inclusion bodies containing htt. Flanking sequences directly adjacent to the poly(Q) domain, such as the first 17 amino acids on the N terminus (Nt17) and the polyproline (poly(P)) domain on the C-terminal side of the poly(Q) domain, heavily influence aggregation. Additionally, htt interacts with a variety of membraneous structures within the cell, and Nt17 is implicated in lipid binding. To investigate the interaction between htt exon1 and lipid membranes, a combination of in situ atomic force microscopy, Langmuir trough techniques, and vesicle permeability assays were used to directly monitor the interaction of a variety of synthetic poly(Q) peptides with different combinations of flanking sequences (KK-Q35-KK, KK-Q35-P10-KK, Nt17-Q35-KK, and Nt17-Q35-P10-KK) on model membranes and surfaces. Each peptide aggregated on mica, predominately forming extended, fibrillar aggregates. In contrast, poly(Q) peptides that lacked the Nt17 domain did not appreciably aggregate on or insert into lipid membranes. Nt17 facilitated the interaction of peptides with lipid surfaces, whereas the poly(P) region enhanced this interaction. The aggregation of Nt17-Q35-P10-KK on the lipid bilayer closely resembled that of a htt exon1 construct containing 35 repeat glutamines. Collectively, this data suggests that the Nt17 domain plays a critical role in htt binding and aggregation on lipid membranes, and this lipid/htt interaction can be further modulated by the presence of the poly(P) domain.
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Affiliation(s)
- Kathleen A Burke
- C Eugene Bennett Department of Chemistry, West Virginia University, Morgantown, West Virginia 26505, USA
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20
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El-Khouri RJ, Frey SL, Szmodis AW, Hall E, Kauffman KJ, Patten TE, Lee KYC, Parikh AN. A stripe-to-droplet transition driven by conformational transitions in a binary lipid-lipopolymer mixture at the air-water interface. Langmuir 2011; 27:1900-1906. [PMID: 21244080 DOI: 10.1021/la104175f] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
We report the observation of an unusual stripe-droplet transition in precompressed Langmuir monolayers consisting of mixtures of poly(ethylene) glycol (PEG) amphiphiles and phospholipids. This highly reproducible and fully reversible transition occurs at approximately zero surface pressure during expansion (or compression) of the monolayer following initial compression into a two-dimensional solid phase. It is characterized by spontaneous emergence of an extended, disordered stripe-like morphology from an optically homogeneous phase during gradual expansion. These stripe patterns appear as a transient feature and continuously progress, involving gradual coarsening and ultimate transformation into a droplet morphology upon further expansion. Furthermore, varying relative concentrations of the two amphiphiles and utilizing amphiphiles with considerably longer ethylene glycol headgroups reveal that this pattern evolution occurs in narrow concentration regimes, values of which depend on ethylene oxide headgroup size. These morphological transitions are reminiscent of those seen during a passage through a critical point by variations in thermodynamic parameters (e.g., temperature or pressure) as well as those involving spinodal decomposition. While the precise mechanism cannot be ascertained using present experiments alone, our observations can be reconciled in terms of modulations in competing interactions prompted by the pancake-mushroom-brush conformational transitions of the ethylene glycol headgroup. This in turn suggests that the conformational degree of freedom represents an independent order parameter, or a switch, which can induce large-scale structural reorganization in amphiphilic monolayers. Because molecular conformational changes are pervasive in biological membranes, we speculate that such conformational transition-induced pattern evolution might provide a physical mechanism by which membrane processes are amplified.
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Affiliation(s)
- Rita J El-Khouri
- Department of Chemistry, University of California, Davis, California 95616, United States
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21
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Kauffman K, Davidson MT, Frey SL. Phospholipid Headgroup Charge Modifies Condensing Effect of Gangliosides on Lipid Films. Biophys J 2011. [DOI: 10.1016/j.bpj.2010.12.3592] [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: 10/18/2022] Open
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22
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Davidson MT, Frey SL. Condensing and Fluidizing Effects of Gangliosides on Various Phospholipid Films. Biophys J 2010. [DOI: 10.1016/j.bpj.2009.12.1560] [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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23
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Frey SL, Pocivavsek L, Waring AJ, Walther FJ, Hernandez-Juviel JM, Ruchala P, Lee KYC. Functional importance of the NH2-terminal insertion sequence of lung surfactant protein B. Am J Physiol Lung Cell Mol Physiol 2009; 298:L335-47. [PMID: 20023175 DOI: 10.1152/ajplung.00190.2009] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Lung surfactant protein B (SP-B) is required for proper surface activity of pulmonary surfactant. In model lung surfactant lipid systems composed of saturated and unsaturated lipids, the unsaturated lipids are removed from the film at high compression. It is thought that SP-B helps anchor these lipids closely to the monolayer in three-dimensional cylindrical structures termed "nanosilos" seen by atomic force microscopy imaging of deposited monolayers at high surface pressures. Here we explore the role of the SP-B NH(2) terminus in the formation and stability of these cylindrical structures, specifically the distribution of lipid stack height, width, and density with four SP-B truncation peptides: SP-B 1-25, SP-B 9-25, SP-B 11-25, and SP-B 1-25Nflex (prolines 2 and 4 substituted with alanine). The first nine amino acids, termed the insertion sequence and the interface seeking tryptophan residue 9, are shown to stabilize the formation of nanosilos while an increase in the insertion sequence flexibility (SP-B 1-25Nflex) may improve peptide functionality. This provides a functional understanding of the insertion sequence beyond anchoring the protein to the two-dimensional membrane lining the lung, as it also stabilizes formation of nanosilos, creating reversible repositories for fluid lipids at high compression. In lavaged, surfactant-deficient rats, instillation of a mixture of SP-B 1-25 (as a monomer or dimer) and synthetic lung lavage lipids quickly improved oxygenation and dynamic compliance, whereas SP-B 11-25 surfactants showed oxygenation and dynamic compliance values similar to that of lipids alone, demonstrating a positive correlation between formation of stable, but reversible, nanosilos and in vivo efficacy.
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Affiliation(s)
- Shelli L Frey
- Department of Chemistry, Institute for Biophysical Dynamics and James Franck Institute, The University of Chicago,929 E. 57 St., Chicago, IL 60637, USA
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Stenger PC, Wu G, Miller CE, Chi EY, Frey SL, Lee KYC, Majewski J, Kjaer K, Zasadzinski JA. X-ray diffraction and reflectivity validation of the depletion attraction in the competitive adsorption of lung surfactant and albumin. Biophys J 2009; 97:777-86. [PMID: 19651036 DOI: 10.1016/j.bpj.2009.05.017] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2009] [Revised: 05/03/2009] [Accepted: 05/05/2009] [Indexed: 12/22/2022] Open
Abstract
Lung surfactant (LS) and albumin compete for the air-water interface when both are present in solution. Equilibrium favors LS because it has a lower equilibrium surface pressure, but the smaller albumin is kinetically favored by faster diffusion. Albumin at the interface creates an energy barrier to subsequent LS adsorption that can be overcome by the depletion attraction induced by polyethylene glycol (PEG) in solution. A combination of grazing incidence x-ray diffraction (GIXD), x-ray reflectivity (XR), and pressure-area isotherms provides molecular-resolution information on the location and configuration of LS, albumin, and polymer. XR shows an average electron density similar to that of albumin at low surface pressures, whereas GIXD shows a heterogeneous interface with coexisting LS and albumin domains at higher surface pressures. Albumin induces a slightly larger lattice spacing and greater molecular tilt, similar in effect to a small decrease in the surface pressure. XR shows that adding PEG to the LS-albumin subphase restores the characteristic LS electron density profile at the interface, and confirms that PEG is depleted near the interface. GIXD shows the same LS Bragg peaks and Bragg rods as on a pristine interface, but with a more compact lattice corresponding to a small increase in the surface pressure. These results confirm that albumin adsorption creates a physical barrier that inhibits LS adsorption, and that PEG in the subphase generates a depletion attraction between the LS aggregates and the interface that enhances LS adsorption without substantially altering the structure or properties of the LS monolayer.
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Affiliation(s)
- Patrick C Stenger
- Department of Chemical Engineering, University of California, Santa Barbara, California, USA
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Ratajczak MK, Chi EY, Frey SL, Cao KD, Luther LM, Lee KYC, Majewski J, Kjaer K. Ordered nanoclusters in lipid-cholesterol membranes. Phys Rev Lett 2009; 103:028103. [PMID: 19659249 DOI: 10.1103/physrevlett.103.028103] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/21/2008] [Indexed: 05/28/2023]
Abstract
X-ray diffraction of sphingomyelin-dihydrocholesterol (SM-DChol) monolayers revealed short-ranged ( approximately 25 A) 2D ordering. These nanoclusters show two distinct regions: below the cusp point of the phase diagram (35 mol% DChol), a constant d spacing was observed; above the cusp, the d spacing increases linearly with DChol in accordance to Vegard's law for binary alloys. The components in this lipidic alloy are thus a 65ratio35 SM-DChol entity and excess DChol. Reflectivity data further support the emergence above the cusp of an uncomplexed DChol population with greater vertical mobility.
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Affiliation(s)
- Maria K Ratajczak
- Department of Physics, Institute for Biophysical Dynamics, and The James Franck Institute, The University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, USA
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26
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Frey SL, Chi EY, Majewski J, Kjaer K, Lee KYC. Condensing And Fluidizing Effects Of Structurally Related Gangliosides On Phospholipid Films. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.2306] [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: 11/24/2022] Open
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Frey SL, El-Khouri R, Parikh AN, Lee KYC. Critical Instability Leads To Labyrinthine Transition In Binary Lipid/Polymer Monolayers. Biophys J 2009. [DOI: 10.1016/j.bpj.2008.12.2370] [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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28
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Ishitsuka Y, Arnt L, Majewski J, Frey SL, Ratajczak M, Kjaer K, Tew GN, Lee KYC. Amphiphilic Poly(phenyleneethynylene)s Can Mimic Antimicrobial Peptide Membrane Disordering Effect by Membrane Insertion [J. Am. Chem. Soc. 2006, 128, 13123−13129]. J Am Chem Soc 2008. [DOI: 10.1021/ja079952w] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Pocivavsek L, Frey SL, Krishan K, Gavrilov K, Ruchala P, Waring AJ, Walther FJ, Dennin M, Witten TA, Lee KYC. Lateral stress relaxation and collapse in lipid monolayers. Soft Matter 2008; 4:2019-2029. [PMID: 19657472 PMCID: PMC2720559 DOI: 10.1039/b804611e] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Surfactants at air/water interfaces are often subjected to mechanical stresses as the interfaces they occupy are reduced in area. The most well characterized forms of stress relaxation in these systems are first order phase transitions from lower density to higher density phases. Here we study stress relaxation in lipid monolayers that occurs once chemical phase transitions have been exhausted. At these highly compressed states, the monolayer undergoes global mechanical relaxations termed collapse. By studying four different types of monolayers, we determine that collapse modes are most closely linked to in-plane rigidity. We characterize the rigidity of the monolayer by analyzing in-plane morphology on numerous length scales. More rigid monolayers collapse out-of-plane via a hard elastic mode similar to an elastic membrane, while softer monolayers relax in-plane by shearing.
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Affiliation(s)
- Luka Pocivavsek
- Department of Chemistry, Institute for Biophysical Dynamics, James Franck Institute, University of Chicago, Chicago, IL, USA. E-mail:
| | - Shelli L. Frey
- Department of Chemistry, Institute for Biophysical Dynamics, James Franck Institute, University of Chicago, Chicago, IL, USA. E-mail:
| | - Kapilanjan Krishan
- Department of Physics and Astrophysics, University of California, Irvine, CA, USA
| | - Kseniya Gavrilov
- Department of Chemistry, Institute for Biophysical Dynamics, James Franck Institute, University of Chicago, Chicago, IL, USA. E-mail:
| | - Piotr Ruchala
- Department of Medicine, UCLA School of Medicine, Los Angeles, CA, USA
| | - Alan J. Waring
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Los Angeles, CA, USA
- Department of Medicine, UCLA School of Medicine, Los Angeles, CA, USA
| | - Frans J. Walther
- Los Angeles Biomedical Research Institute at Harbor-UCLA Medical Center, Los Angeles, CA, USA
| | - Michael Dennin
- Department of Physics and Astrophysics, University of California, Irvine, CA, USA
| | - Thomas A. Witten
- James Franck Institute and Department of Physics, University of Chicago, Chicago, IL, USA
| | - Ka Yee C. Lee
- Department of Chemistry, Institute for Biophysical Dynamics, James Franck Institute, University of Chicago, Chicago, IL, USA. E-mail:
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Frey SL, Zhang D, Carignano MA, Szleifer I, Lee KYC. Effects of block copolymer's architecture on its association with lipid membranes: experiments and simulations. J Chem Phys 2007; 127:114904. [PMID: 17887877 DOI: 10.1063/1.2768947] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
Triblock copolymers of the form poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide) (PEO-PPO-PEO) have been shown to effectively interact with and restore activity of damaged cell membranes. To better understand the interaction between these polymers and cell membranes, we have modeled the outer leaflet of a cell membrane with a lipid monolayer spread at the air-water interface and injected poloxamers of varying architectures into the subphase beneath the monolayer. Subsequent interactions of the polymer with the monolayer upon compression were monitored with concurrent Langmuir isotherm and fluorescence microscopy measurements. Monte Carlo simulations were run in parallel using a coarse-grained model to capture interactions between lipids and poloxamers. Changing the ratio of the PEO to PPO block lengths (NPEO:NPPO) affects the equilibrium spreading pressure of the polymer. Poloxamers with a relatively longer central hydrophobic block are less soluble, resulting in more polymer adsorbed to the interface and therefore a higher equilibrium spreading pressure. Simulation results show that changing the poloxamer structure effectively affects its solubility. This is also reflected in the degree of lipid corralling as poloxamers with a higher chemical potential (and resulting higher equilibrium spreading pressure) cause the neighboring lipid domains to be more ordered. Upon lateral compression of the monolayers, the polymer is expelled from the film beyond a certain squeeze-out pressure. A poloxamer with a higher NPEO:NPPO ratio (with either NPEO or NPPO held constant in each series) has a lower squeeze-out pressure. Likewise when the total size of the polymer is varied with a constant hydrophilic:hydrophobic ratio, smaller poloxamers are squeezed out at a lower pressure. Our simulation results capture the trends of our experimental observations, both indicating how the interactions between lipids and poloxamers can be tuned by the polymer architecture.
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Affiliation(s)
- Shelli L Frey
- Department of Chemistry, Institute for Biophysical Dynamics and James Franck Institute, The University of Chicago, Chicago, Illinois 60637, USA
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Abstract
F68, a triblock copolymer of the form poly(ethylene oxide)-poly(propylene oxide)-poly(ethylene oxide), is found to effectively seal damaged cell membranes. To better understand the molecular interaction between F68 and cells, we have modeled the outer leaflet of a cell membrane with a dipalmitoylphosphatidylcholine (DPPC) monolayer spread at the air-water interface and introduced poloxamer into the subphase. Subsequent interactions of the polymer with the monolayer either upon expansion or compression were monitored using concurrent Langmuir isotherm and fluorescence microscopy measurements. To alter the activity of the poloxamer, a range of subphase temperatures from 5 to 37 degrees C was used. Lower temperatures increase the solubility of the poloxamer in the subphase and therefore lessen the amount of material at the interface, resulting in a lower equilibrium spreading pressure. Additionally, changes in temperature affect the phase behavior of DPPC. Below the triple point, the monolayer is condensed at pertinent polymer insertion pressures; for temperatures immediately above the triple point, the monolayer is a heterogeneous mix of liquid expanded and condensed phase; for the highest temperature measured, the DPPC monolayer remains completely fluid. At all temperatures, F68 inserts into DPPC monolayers at its equilibrium spreading pressure. Upon compression of the monolayer, polymers are squeezed-out at surface pressures notably higher than those for insertion, with higher temperatures leading to a higher squeeze-out pressure. An increase in temperature decreases the solvent quality of water for the poloxamer, lowering solubility of the polymer in the subphase and thus increasing its propensity to be maintained within the monolayer to higher pressures.
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Affiliation(s)
- Shelli L Frey
- Department of Chemistry, Institute for Biophysical Dynamics and James Franck Institute, The University of Chicago, Chicago, IL 60637, USA
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Abstract
There is increasing evidence that a class of cell membrane glycolipids, gangliosides, can mediate the fibrillogenesis and toxicity of Alzheimer's disease amyloid-beta peptide (Abeta). Using lipid monolayers and vesicles as model membranes, we measured the insertion of Abeta into 1,2-dipalmitoyl-sn-glycero-3-phosphocholine (DPPC)-ganglioside GM1 monolayers to probe Abeta-GM1 interactions, imaged the effects of Abeta insertion on monolayer morphology, and measured the rate of Abeta fibril formation when incubated with 1-palmitoyl-2-oleoyl-sn-glycero-3-phosphocholine (POPC)-GM1 vesicles. Furthermore, the location of Abeta association in the monolayer was assessed by dual-probe fluorescence experiments. Abeta exhibited direct and favorable interactions with GM1 as Abeta insertion monotonically increased with GM1 concentration, despite increases in monolayer rigidity at low GM1 levels. At low GM1 concentrations, Abeta preferentially inserted into the disordered, liquid expanded phase. At higher GM1 concentrations, Abeta inserted more uniformly into the monolayer, resulting in no detectable preferences for either the disordered or condensed phase. Abeta insertion led to the disruption of membrane morphology, specifically to the expansion of the disordered phase at low GM1 concentrations and significant disruption of the condensed domains at higher GM1 concentrations. During incubation with POPC vesicles containing physiological levels of GM1, the association of Abeta with vesicles seeded the formation of Abeta fibrils. In conclusion, favorable interactions between Abeta and GM1 in the cell membrane may provide a mechanism for Abeta fibrillogenesis in vivo, and Abeta-induced disruption of the cell membrane may provide a pathway by which Abeta exerts toxicity.
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Affiliation(s)
- Eva Y Chi
- Department of Chemistry, The Institute for Biophysical Dynamics, and the James Franck Institute, University of Chicago, 929 E. 57th Street, Chicago, Illinois 60637, USA
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Abstract
This Letter reports a novel approach to the fabrication of a biomimicking surface by modification of an end-functionalizable smooth polymer cushion constructed via chemoselective ligation with a phospholipid-like molecule containing oxyamine groups. The mobility of a phospholipid bilayer formed by vesicle fusion on the phospholipid-like molecule terminated polymer film was characterized by fluorescence recovery after bleaching. Platelet adhesion, as one measure of biocompatibility of the film was also studied and compared to other surfaces such as polyethylene or poly(dimethylsiloxane). The results show that the end-functionalized smooth polymer cushion has potential as a biocompatible platform to reconstitute membrane proteins.
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Affiliation(s)
- Dong-Chan Lee
- Department of Chemistry and The James Frank Institute, The University of Chicago, 5735 South Ellis Avenue, Chicago, Illinois 60637, USA
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Schumacher MA, Jong BE, Frey SL, Sudanagunta SP, Capra NF, Levine JD. The stretch-inactivated channel, a vanilloid receptor variant, is expressed in small-diameter sensory neurons in the rat. Neurosci Lett 2000; 287:215-8. [PMID: 10863033 DOI: 10.1016/s0304-3940(00)01181-2] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [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: 10/18/2022]
Abstract
Exposure to hypertonic conditions is known to produce pain and activate small-diameter sensory neurons. Recently, the vanilloid receptor variant and stretch-inactivated ion channel (SIC) was cloned and shown to mediate an inward current in response to cell shrinkage. Since other vanilloid receptors have been previously shown to mediate nociception, we investigated whether SIC is expressed in sensory neurons. Using reverse transcription-polymerase chain reaction and in situ hybridization techniques, we identified SIC in the neurons of dorsal root and trigeminal ganglia. Furthermore, SIC was found to be present almost exclusively in the small-diameter sensory neurons, which includes the nociceptive population. Since SIC is activated by cell shrinkage, it may participate in the mediation of pain produced by hypertonic stimuli.
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Affiliation(s)
- M A Schumacher
- Department of Anesthesia and Perioperative Care, University of California, San Francisco 94143-0648, USA.
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