1
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Moxam J, Naylon S, Richaud AD, Zhao G, Padilla A, Roche SP. Passive Membrane Permeability of Sizable Acyclic β-Hairpin Peptides. ACS Med Chem Lett 2023; 14:278-284. [PMID: 36923919 PMCID: PMC10009788 DOI: 10.1021/acsmedchemlett.2c00486] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2022] [Accepted: 01/24/2023] [Indexed: 01/28/2023] Open
Abstract
The recent shift toward increasingly larger drug modalities has created a significant demand for novel classes of compounds with high membrane permeability that can inhibit intracellular protein-protein interactions (PPIs). While major advances have been made in the design of cell-permeable helices, stapled β-sheets, and cyclic peptides, the development of large acyclic β-hairpins lags far behind. Therefore, we investigated a series of 26 β-hairpins (MW > 1.6 kDa) belonging to a chemical space far beyond the Lipinski "rule of five" (fbRo5) and showed that, in addition to their innate plasticity, the lipophilicity of these peptides (log D 7.4 ≈ 0 ± 0.7) can be tuned to drastically improve the balance between aqueous solubility and passive membrane permeability.
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Affiliation(s)
- Jillene Moxam
- Department
of Chemistry and Biochemistry, Florida Atlantic
University, Boca Raton, Florida 33431, United States
| | - Sarah Naylon
- Department
of Chemistry and Biochemistry, Florida Atlantic
University, Boca Raton, Florida 33431, United States
| | - Alexis D. Richaud
- Department
of Chemistry and Biochemistry, Florida Atlantic
University, Boca Raton, Florida 33431, United States
| | - Guangkuan Zhao
- Department
of Chemistry and Biochemistry, Florida Atlantic
University, Boca Raton, Florida 33431, United States
| | - Alberto Padilla
- Department
of Natural Science, Keiser University, Fort Lauderdale, Florida 33309, United States
| | - Stéphane P. Roche
- Department
of Chemistry and Biochemistry, Florida Atlantic
University, Boca Raton, Florida 33431, United States
- Center
for Molecular Biology and Biotechnology, Florida Atlantic University, Jupiter, Florida 33458, United States
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2
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Proteomics and Molecular Docking Analyses Reveal the Bio-Chemical and Molecular Mechanism Underlying the Hypolipidemic Activity of Nano-Liposomal Bioactive Peptides in 3T3-L1 Adipocytes. Foods 2023; 12:foods12040780. [PMID: 36832854 PMCID: PMC9956075 DOI: 10.3390/foods12040780] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/09/2023] [Revised: 02/07/2023] [Accepted: 02/08/2023] [Indexed: 02/16/2023] Open
Abstract
Obesity is a global health concern. Physical activities and eating nutrient-rich functional foods can prevent obesity. In this study, nano-liposomal encapsulated bioactive peptides (BPs) were developed to reduce cellular lipids. The peptide sequence NH2-PCGVPMLTVAEQAQ-CO2H was chemically synthesized. The limited membrane permeability of the BPs was improved by encapsulating the BPs with a nano-liposomal carrier, which was produced by thin-layer formation. The nano-liposomal BPs had a diameter of ~157 nm and were monodispersed in solution. The encapsulation capacity was 61.2 ± 3.2%. The nano-liposomal BPs had no significant cytotoxicity on the tested cells, keratinocytes, fibroblasts, and adipocytes. The in vitro hypolipidemic activity significantly promoted the breakdown of triglycerides (TGs). Lipid droplet staining was correlated with TG content. Proteomics analysis identified 2418 differentially expressed proteins. The nano-liposomal BPs affected various biochemical pathways beyond lipolysis. The nano-liposomal BP treatment decreased the fatty acid synthase expression by 17.41 ± 1.17%. HDOCK revealed that the BPs inhibited fatty acid synthase (FAS) at the thioesterase domain. The HDOCK score of the BPs was lower than that of orlistat, a known obesity drug, indicating stronger binding. Proteomics and molecular docking analyses confirmed that the nano-liposomal BPs were suitable for use in functional foods to prevent obesity.
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3
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Yang Y, Distaffen H, Jalali S, Nieuwkoop AJ, Nilsson BL, Dias CL. Atomic Insights into Amyloid-Induced Membrane Damage. ACS Chem Neurosci 2022; 13:2766-2777. [PMID: 36095304 DOI: 10.1021/acschemneuro.2c00446] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023] Open
Abstract
Amphipathic peptides can cause biological membranes to leak either by dissolving their lipid content via a detergent-like mechanism or by forming pores on the membrane surface. These modes of membrane damage have been related to the toxicity of amyloid peptides and to the activity of antimicrobial peptides. Here, we perform the first all-atom simulations in which membrane-bound amphipathic peptides self-assemble into β-sheets that subsequently either form stable pores inside the bilayer or drag lipids out of the membrane surface. An analysis of these simulations shows that the acyl tail of lipids interact strongly with non-polar side chains of peptides deposited on the membrane. These strong interactions enable lipids to be dragged out of the bilayer by oligomeric structures accounting for detergent-like damage. They also disturb the orientation of lipid tails in the vicinity of peptides. These distortions are minimized around pore structures. We also show that membrane-bound β-sheets become twisted with one of their extremities partially penetrating the lipid bilayer. This allows peptides on opposite leaflets to interact and form a long transmembrane β-sheet, which initiates poration. In simulations, where peptides are deposited on a single leaflet, the twist in β-sheets allows them to penetrate the membrane and form pores. In addition, our simulations show that fibril-like structures produce little damage to lipid membranes, as non-polar side chains in these structures are unavailable to interact with the acyl tail of lipids.
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Affiliation(s)
- Yanxing Yang
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102-1982, United States
| | - Hannah Distaffen
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Sharareh Jalali
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102-1982, United States
| | - Andrew J Nieuwkoop
- Department of Chemistry and Chemical Biology, Rutgers University, Piscataway, New Jersey 08854, United States
| | - Bradley L Nilsson
- Department of Chemistry, University of Rochester, Rochester, New York 14627, United States
| | - Cristiano L Dias
- Department of Physics, New Jersey Institute of Technology, Newark, New Jersey 07102-1982, United States
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4
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Pohl C, Effantin G, Kandiah E, Meier S, Zeng G, Streicher W, Segura DR, Mygind PH, Sandvang D, Nielsen LA, Peters GHJ, Schoehn G, Mueller-Dieckmann C, Noergaard A, Harris P. pH- and concentration-dependent supramolecular assembly of a fungal defensin plectasin variant into helical non-amyloid fibrils. Nat Commun 2022; 13:3162. [PMID: 35672293 PMCID: PMC9174238 DOI: 10.1038/s41467-022-30462-w] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 04/28/2022] [Indexed: 02/04/2023] Open
Abstract
Self-assembly and fibril formation play important roles in protein behaviour. Amyloid fibril formation is well-studied due to its role in neurodegenerative diseases and characterized by refolding of the protein into predominantly β-sheet form. However, much less is known about the assembly of proteins into other types of supramolecular structures. Using cryo-electron microscopy at a resolution of 1.97 Å, we show that a triple-mutant of the anti-microbial peptide plectasin, PPI42, assembles into helical non-amyloid fibrils. The in vitro anti-microbial activity was determined and shown to be enhanced compared to the wildtype. Plectasin contains a cysteine-stabilised α-helix-β-sheet structure, which remains intact upon fibril formation. Two protofilaments form a right-handed protein fibril. The fibril formation is reversible and follows sigmoidal kinetics with a pH- and concentration dependent equilibrium between soluble monomer and protein fibril. This high-resolution structure reveals that α/β proteins can natively assemble into fibrils. Here the authors report the cryo-EM structure of a triple-mutant of the anti-microbial peptide plectasin, PPI42, assembling in a pH- and concentration dependent manner into helical non-amyloid fibrils. The fibrils formation is reversible, and follows a sigmoidal kinetics. The fibrils adopt a right-handed helical superstructure composed by two protofilaments, stabilized by an outer hydrophobic ring and an inner hydrophobic centre. These findings reveal that α/β proteins can natively assemble into fibrils.
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5
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Shao N, Yuan L, Ma P, Zhou M, Xiao X, Cong Z, Wu Y, Xiao G, Fei J, Liu R. Heterochiral β-Peptide Polymers Combating Multidrug-Resistant Cancers Effectively without Inducing Drug Resistance. J Am Chem Soc 2022; 144:7283-7294. [PMID: 35420800 DOI: 10.1021/jacs.2c00452] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Multidrug resistance to chemotherapeutic drugs is one of the major causes for the failure of cancer treatment. Therefore, there is an urgent need to develop anticancer agents that can combat multidrug-resistant cancers effectively and mitigate drug resistance. Here, we report a rational design of anticancer heterochiral β-peptide polymers as synthetic mimics of host defense peptides to combat multidrug-resistant cancers. The optimal polymer shows potent and broad-spectrum anticancer activities against multidrug-resistant cancer cells and is insusceptible to anticancer drug resistance owing to its membrane-damaging mechanism. The in vivo study indicates that the optimal polymer efficiently inhibits the growth and distant transfer of solid tumors and the metastasis and seeding of circulating tumor cells. Moreover, the polymer shows excellent biocompatibility during anticancer treatment on animals. In addition, the β-peptide polymers address those prominent shortcomings of anticancer peptides and have superior stability against proteolysis, easy synthesis in large scale, and low cost. Collectively, the structural diversity and superior anticancer performance of β-peptide polymers imply an effective strategy in designing and finding anticancer agents to combat multidrug-resistant cancers effectively while mitigating drug resistance.
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Affiliation(s)
- Ning Shao
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Ling Yuan
- Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Pengcheng Ma
- Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Min Zhou
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Ximian Xiao
- Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Zihao Cong
- Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Yueming Wu
- Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
| | - Guohui Xiao
- Department of General Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Jian Fei
- Department of General Surgery, Ruijin Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200025, China
| | - Runhui Liu
- State Key Laboratory of Bioreactor Engineering, East China University of Science and Technology, Shanghai 200237, China.,Key Laboratory for Ultrafine Materials of Ministry of Education, Frontiers Science Center for Materiobiology and Dynamic Chemistry, Shanghai Frontiers Science Center of Optogenetic Techniques for Cell Metabolism, Research Center for Biomedical Materials of Ministry of Education, School of Materials Science and Engineering, East China University of Science and Technology, Shanghai 200237, China
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6
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Study of the Lipolysis Effect of Nanoliposome-Encapsulated Ganoderma lucidum Protein Hydrolysates on Adipocyte Cells Using Proteomics Approach. Foods 2021; 10:foods10092157. [PMID: 34574267 PMCID: PMC8468392 DOI: 10.3390/foods10092157] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 09/08/2021] [Accepted: 09/10/2021] [Indexed: 01/15/2023] Open
Abstract
Excessive lipid accumulation is a serious condition. Therefore, we aimed at developing safe strategies using natural hypolipidemic products. Lingzhi is an edible fungus and potential lipid suppression stimulant. To use Lingzhi as a functional hyperlipidemic ingredient, response surface methodology (RSM) was conducted to optimize the time (X1) and enzyme usage (X2) for the hydrolysate preparation with the highest degree of hydrolysis (DH) and % yield. We encapsulated the hydrolysates using nanoscale liposomes and used proteomics to study how these nano-liposomal hydrolysates could affect lipid accumulation in adipocyte cells. RSM analysis revealed X1 at 8.63 h and X2 at 0.93% provided the highest values of DH and % yields were 33.99% and 5.70%. The hydrolysates were loaded into liposome particles that were monodispersed. The loaded nano-liposomal particles did not significantly affect cell survival rates. The triglyceride (TG) breakdown in adipocytes showed a higher TG increase compared to the control. Lipid staining level upon the liposome treatment was lower than that of the control. Proteomics revealed 3425 proteins affected by the liposome treatment, the main proteins being TSSK5, SMU1, GRM7, and KLC4, associated with various biological functions besides lipolysis. The nano-liposomal Linzghi hydrolysate might serve as novel functional ingredients in the treatment and prevention of obesity
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7
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Is the Membrane Lipid Matrix a Key Target for Action of Pharmacologically Active Plant Saponins? Int J Mol Sci 2021; 22:ijms22063167. [PMID: 33804648 PMCID: PMC8003763 DOI: 10.3390/ijms22063167] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2021] [Revised: 02/28/2021] [Accepted: 03/18/2021] [Indexed: 11/25/2022] Open
Abstract
This study was focused on the molecular mechanisms of action of saponins and related compounds (sapogenins and alkaloids) on model lipid membranes. Steroids and triterpenes were tested. A systematic analysis of the effects of these chemicals on the physicochemical properties of the lipid bilayers and on the formation and functionality of the reconstituted ion channels induced by antimicrobial agents was performed. It was found that digitonin, tribulosin, and dioscin substantially reduced the boundary potential of the phosphatidylcholine membranes. We concluded that saponins might affect the membrane boundary potential by restructuring the membrane hydration layer. Moreover, an increase in the conductance and lifetime of gramicidin A channels in the presence of tribulosin was due to an alteration in the membrane dipole potential. Differential scanning microcalorimetry data indicated the key role of the sapogenin core structure (steroid or triterpenic) in affecting lipid melting and disordering. We showed that an alteration in pore forming activity of syringomycin E by dioscin might be due to amendments in the lipid packing. We also found that the ability of saponins to disengage the fluorescent marker calcein from lipid vesicles might be also determined by their ability to induce a positive curvature stress.
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8
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DuPai CD, Davies BW, Wilke CO. A systematic analysis of the beta hairpin motif in the Protein Data Bank. Protein Sci 2021; 30:613-623. [PMID: 33389765 DOI: 10.1002/pro.4020] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Revised: 12/29/2020] [Accepted: 12/29/2020] [Indexed: 12/31/2022]
Abstract
The beta hairpin motif is a ubiquitous protein structural motif that can be found in molecules across the tree of life. This motif, which is also popular in synthetically designed proteins and peptides, is known for its stability and adaptability to broad functions. Here, we systematically probe all 49,000 unique beta hairpin substructures contained within the Protein Data Bank (PDB) to uncover key characteristics correlated with stable beta hairpin structure, including amino acid biases and enriched interstrand contacts. We find that position specific amino acid preferences, while seen throughout the beta hairpin structure, are most evident within the turn region, where they depend on subtle turn dynamics associated with turn length and secondary structure. We also establish a set of broad design principles, such as the inclusion of aspartic acid residues at a specific position and the careful consideration of desired secondary structure when selecting residues for the turn region, that can be applied to the generation of libraries encoding proteins or peptides containing beta hairpin structures.
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Affiliation(s)
- Cory D DuPai
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA.,Department of Integrative Biology, University of Texas at Austin, Austin, Texas, USA
| | - Bryan W Davies
- Department of Molecular Biosciences, University of Texas at Austin, Austin, Texas, USA.,Center for Systems and Synthetic Biology, John Ring LaMontagne Center for Infectious Diseases, Institute for Cellular and Molecular Biology, University of Texas at Austin, Austin, Texas, USA
| | - Claus O Wilke
- Department of Integrative Biology, University of Texas at Austin, Austin, Texas, USA
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9
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Levin A, Hakala TA, Schnaider L, Bernardes GJL, Gazit E, Knowles TPJ. Biomimetic peptide self-assembly for functional materials. Nat Rev Chem 2020. [DOI: 10.1038/s41570-020-0215-y] [Citation(s) in RCA: 162] [Impact Index Per Article: 40.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
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10
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Improved cytosolic delivery of macromolecules through dimerization of attenuated lytic peptides. Bioorg Med Chem Lett 2020; 30:127362. [DOI: 10.1016/j.bmcl.2020.127362] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/13/2020] [Accepted: 06/17/2020] [Indexed: 01/01/2023]
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11
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Liposomal membrane permeability assessment by fluorescence techniques: Main permeabilizing agents, applications and challenges. Int J Pharm 2020; 580:119198. [PMID: 32169353 DOI: 10.1016/j.ijpharm.2020.119198] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2019] [Revised: 02/19/2020] [Accepted: 03/02/2020] [Indexed: 01/08/2023]
Abstract
Liposomes are lipid vesicles made of one or multiple lipid bilayers surrounding an internal aqueous core. They are broadly employed as models to study membrane structure and properties. Among these properties, liposome membrane permeability is crucial and widely assessed by fluorescence techniques. The first part of this review is devoted to describe the various techniques used for membrane permeability assessment. Attention is paid to fluorescence techniques based on vesicle leakage of self-quenching probes, dye/quencher pair or cation/ligand pair. Secondly, the membrane-active agents inducing membrane permeabilization is presented and details on their mechanisms of action are given. Emphasis is also laid on the intrinsic and extrinsic factors that can modulate the membrane permeability. Hence, a suitable liposomal membrane should be formulated according to the aim of the study and its application.
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12
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Dutta S, Watson BG, Mattoo S, Rochet JC. Calcein Release Assay to Measure Membrane Permeabilization by Recombinant Alpha-Synuclein. Bio Protoc 2020; 10:e3690. [PMID: 32953942 DOI: 10.21769/bioprotoc.3690] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Lipid membranes are involved in regulating biochemical and biological processes and in modulating the selective permeability of cells, organelles, and vesicles. Membrane composition, charge, curvature, and fluidity all have concerted effects on cellular signaling and homeostasis. The ability to prepare artificial lipid assemblies that mimic biological membranes has enabled investigators to obtain considerable insight into biomolecule-membrane interactions. Lipid nanoscale assemblies can vary greatly in size and composition and can consist of a single lipid monolayer, a bilayer, or other more complex assemblies. This structural diversity makes liposomes suitable for a wide variety of biochemical and clinical applications. Here, we describe a calcein dye leakage assay that we have developed to monitor phospholipid vesicle disruption by alpha-synuclein (αSyn), a presynaptic protein that plays a central role in Parkinson's disease (PD). We present data showing the effect of adenylylation of αSyn on αSyn-mediated vesicle disruption as an example. This assay can be used to study the effect of mutations or post-translational modifications on αSyn-membrane interactions, to identify protein binding partners or chemical entities that perturb these interactions, and to study the effects of different lipids on the permeabilization activity of αSyn or any other protein.
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Affiliation(s)
- Sayan Dutta
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA.,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
| | - Ben G Watson
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA
| | - Seema Mattoo
- Department of Biological Sciences, Purdue University, West Lafayette, IN 47907, USA.,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA.,Purdue Institute of Inflammation, Immunology and Infectious Disease, Purdue University, West Lafayette, IN 47907, USA
| | - Jean-Christophe Rochet
- Department of Medicinal Chemistry and Molecular Pharmacology, Purdue University, West Lafayette, IN 47907, USA.,Purdue Institute for Integrative Neuroscience, Purdue University, West Lafayette, IN 47907, USA
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13
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Chen M, Daddy J.C. KA, Su Z, Guissi NEI, Xiao Y, Zong L, Ping Q. Folate Receptor-Targeting and Reactive Oxygen Species-Responsive Liposomal Formulation of Methotrexate for Treatment of Rheumatoid Arthritis. Pharmaceutics 2019; 11:E582. [PMID: 31698794 PMCID: PMC6921073 DOI: 10.3390/pharmaceutics11110582] [Citation(s) in RCA: 35] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2019] [Revised: 11/04/2019] [Accepted: 11/04/2019] [Indexed: 12/13/2022] Open
Abstract
Multifunctional nanomedicines with active targeting and stimuli-responsive drug release function utilizing pathophysiological features of the disease are regarded as an effective strategy for treatment of rheumatoid arthritis (RA). Under the inflammatory environment of RA, activated macrophages revealed increased expression of folate receptor and elevated intracellular reactive oxygen species (ROS) level. In this study, we successfully conjugated folate to polyethylene glycol 100 monostearate as film-forming material and further prepared methotrexate (MTX) and catalase (CAT) co-encapsulated liposomes, herein, shortened to FOL-MTX&CAT-L, that could actively target to activated macrophages. Thereafter, elevated intracellular hydrogen peroxide, the main source of ROS, diffused into liposomes and encapsulated CAT catalyzed the decomposition of hydrogen peroxide into oxygen and water. Continuous oxygen-generation inside liposomes would eventually disorganize its structure and release the encapsulated MTX. We characterized the in vitro drug release, cellular uptake and cytotoxicity studies as well as in vivo pharmacokinetics, biodistribution, therapeutic efficacy and safety studies of FOL-MTX&CAT-L. In vitro results revealed that FOL-MTX&CAT-L possessed sufficient ROS-sensitive drug release, displayed an improved cellular uptake through folate-mediated endocytosis and exhibited a higher cytotoxic effect on activated RAW264.7 cells. Moreover, in vivo results showed prolonged blood circulation time of PEGylated liposomes, enhanced accumulation of MTX in inflamed joints of collagen-induced arthritis (CIA) mice, reinforced therapeutic efficacy and minimal toxicity toward major organs. These results imply that FOL-MTX&CAT-L may be used as an effective nanomedicine system for RA treatment.
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Affiliation(s)
| | | | | | | | | | - Li Zong
- State Key Laboratory of Natural Medicines, Department of Pharmaceutics, China Pharmaceutical University, Nanjing 210009, China; (M.C.); (Z.S.); (N.E.I.G.); (Y.X.)
| | - Qineng Ping
- State Key Laboratory of Natural Medicines, Department of Pharmaceutics, China Pharmaceutical University, Nanjing 210009, China; (M.C.); (Z.S.); (N.E.I.G.); (Y.X.)
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14
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Efimova SS, Chulkov EG, Ostroumova OS. Lipid-mediated mode of action of local anesthetics on lipid pores induced by polyenes, peptides and lipopeptides. Colloids Surf B Biointerfaces 2018. [PMID: 29525621 DOI: 10.1016/j.colsurfb.2018.02.051] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The effects of local anesthetics (LAs), namely, lidocaine (LDC), prilocaine (PLC), mepivacaine (MPV), bupivacaine (BPV), procaine (PC), and tetracaine (TTC), on the steady-state transmembrane conductance induced by the cis-side addition of the antifungal polyene macrolide antibiotic, nystatin (NYS), in planar lipid bilayers were studied. The addition of TTC to model membranes comprising DOPC and cholesterol (33 mol%) led to a nearly twenty-fold increase in the steady-state NYS-induced membrane conductance. BPV slightly enhanced the channel-forming activity of polyene. LDC, PLC, MPV, and PC did not affect the NYS-induced transmembrane current. We concluded that the effects of LAs on the channel-forming activity of NYS were in agreement with their effects on the elastic properties of model membranes. The ability of aminoamide LAs to promote calcein leakage from large unilamellar DOPC-vesicles was decreased in the following order: BPV >> LDC ≈ PLC ≈ MPV. LDC, PLC, and MPV produced a graded leakage of fluorescent marker from liposomes, up to 10-13%. A initial sharp jump in fluorescence after the introduction of BPV was attributed to the solubilization of liposomes and the formation of mixed DOPC:BPV-micelles. Differential scanning microcalorimetry (DSC) of large unilamellar DPPC-vesicles showed that the main transition temperature (Tm) is continuously decreased upon increasing concentrations of TTC. A sharp drop in the enthalpy of the transition at higher TTC concentrations indicated a formation of anesthetic/lipid mixed micelles. In contrast to TTC, PC slightly decreased Tm, broadened the DSC signal and did not provoke vesicle-to-micelle transition. Both the calcein leakage and DSC data together with the results of measurements of threshold voltages that are required to cause the lipid bilayer breakdown might indicate an alteration in the curvature lipid packing stress, induced by BPV and TTC. The data presented here lend support to a lipid-mediated mode of LAs action on NYS pores via an alteration in curvature stress near the trans-mouth. Similar results were obtained for several lipid pores, formed by polyene amphotericin B, lipopeptide syringomycin E, and the peptides magainin and melittin. This finding further developed the concept of non-specific regulation of lipid pores by LAs. In conclusion, the combination of nystatin with LAs could be a novel treatment for efficient therapy of superficial and mucosal candidiasis.
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Affiliation(s)
- Svetlana S Efimova
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia.
| | - Evgeny G Chulkov
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
| | - Olga S Ostroumova
- Institute of Cytology of the Russian Academy of Sciences, St. Petersburg 194064, Russia
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15
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Reid KA, Davis CM, Dyer RB, Kindt JT. Binding, folding and insertion of a β-hairpin peptide at a lipid bilayer surface: Influence of electrostatics and lipid tail packing. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2017; 1860:792-800. [PMID: 29291379 DOI: 10.1016/j.bbamem.2017.12.019] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/22/2017] [Revised: 12/12/2017] [Accepted: 12/25/2017] [Indexed: 12/11/2022]
Abstract
Antimicrobial peptides (AMPs) act as host defenses against microbial pathogens. Here we investigate the interactions of SVS-1 (KVKVKVKVdPlPTKVKVKVK), an engineered AMP and anti-cancer β-hairpin peptide, with lipid bilayers using spectroscopic studies and atomistic molecular dynamics simulations. In agreement with literature reports, simulation and experiment show preferential binding of SVS-1 peptides to anionic over neutral bilayers. Fluorescence and circular dichroism studies of a Trp-substituted SVS-1 analogue indicate, however, that it will bind to a zwitterionic DPPC bilayer under high-curvature conditions and folds into a hairpin. In bilayers formed from a 1:1 mixture of DPPC and anionic DPPG lipids, curvature and lipid fluidity are also observed to promote deeper insertion of the fluorescent peptide. Simulations using the CHARMM C36m force field offer complementary insight into timescales and mechanisms of folding and insertion. SVS-1 simulated at an anionic mixed POPC/POPG bilayer folded into a hairpin over a microsecond, the final stage in folding coinciding with the establishment of contact between the peptide's valine sidechains and the lipid tails through a "flip and dip" mechanism. Partial, transient folding and superficial bilayer contact are seen in simulation of the peptide at a zwitterionic POPC bilayer. Only when external surface tension is applied does the peptide establish lasting contact with the POPC bilayer. Our findings reveal the influence of disruption to lipid headgroup packing (via curvature or surface tension) on the pathway of binding and insertion, highlighting the collaborative effort of electrostatic and hydrophobic interactions on interaction of SVS-1 with lipid bilayers.
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Affiliation(s)
- Keon A Reid
- Department of Chemistry, Emory University, 201 Dowman Drive, Atlanta, GA 30322, United States
| | - Caitlin M Davis
- Department of Chemistry, Emory University, 201 Dowman Drive, Atlanta, GA 30322, United States; Department of Chemistry, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States; Department of Physics, University of Illinois at Urbana-Champaign, Urbana, IL 61801, United States
| | - R Brian Dyer
- Department of Chemistry, Emory University, 201 Dowman Drive, Atlanta, GA 30322, United States
| | - James T Kindt
- Department of Chemistry, Emory University, 201 Dowman Drive, Atlanta, GA 30322, United States.
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16
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Newcomb C, Sur S, Lee SS, Yu JM, Zhou Y, Snead ML, Stupp SI. Supramolecular Nanofibers Enhance Growth Factor Signaling by Increasing Lipid Raft Mobility. NANO LETTERS 2016; 16:3042-3050. [PMID: 27070195 PMCID: PMC4948975 DOI: 10.1021/acs.nanolett.6b00054] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/23/2016] [Indexed: 05/30/2023]
Abstract
The nanostructures of self-assembling biomaterials have been previously designed to tune the release of growth factors in order to optimize biological repair and regeneration. We report here on the discovery that weakly cohesive peptide nanostructures in terms of intermolecular hydrogen bonding, when combined with low concentrations of osteogenic growth factor, enhance both BMP-2 and Wnt mediated signaling in myoblasts and bone marrow stromal cells, respectively. Conversely, analogous nanostructures with enhanced levels of internal hydrogen bonding and cohesion lead to an overall reduction in BMP-2 signaling. We propose that the mechanism for enhanced growth factor signaling by the nanostructures is related to their ability to increase diffusion within membrane lipid rafts. The phenomenon reported here could lead to new nanomedicine strategies to mediate growth factor signaling for translational targets.
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Affiliation(s)
- Christina
J. Newcomb
- Department of Materials Science and Engineering Northwestern University, Evanston, Illinois 60208, United States
| | - Shantanu Sur
- Department of Materials Science and Engineering Northwestern University, Evanston, Illinois 60208, United States
| | - Sungsoo S. Lee
- Department of Materials Science and Engineering Northwestern University, Evanston, Illinois 60208, United States
| | - Jeong Min Yu
- Simpson
Querrey Institute for BioNanotechnology, Northwestern University, Chicago, Illinois 60611, United States
| | - Yan Zhou
- Center for Craniofacial Molecular Biology,
Herman Ostrow School of Dentistry of USC, The University of Southern California, Los Angeles, California 90033, United States
| | - Malcolm L. Snead
- Center for Craniofacial Molecular Biology,
Herman Ostrow School of Dentistry of USC, The University of Southern California, Los Angeles, California 90033, United States
| | - Samuel I. Stupp
- Department of Materials Science and Engineering Northwestern University, Evanston, Illinois 60208, United States
- Simpson
Querrey Institute for BioNanotechnology, Northwestern University, Chicago, Illinois 60611, United States
- Department
of Biomedical Engineering, Northwestern
University, Evanston, Illinois 60208, United
States
- Department of Chemistry, Northwestern
University, Evanston, Illinois 60208, United
States
- Department of Medicine, Northwestern
University, Chicago, Illinois 60611, United
States
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17
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Jang H, Banerjee A, Chavan TS, Lu S, Zhang J, Gaponenko V, Nussinov R. The higher level of complexity of K-Ras4B activation at the membrane. FASEB J 2016; 30:1643-55. [PMID: 26718888 PMCID: PMC4799498 DOI: 10.1096/fj.15-279091] [Citation(s) in RCA: 69] [Impact Index Per Article: 8.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2015] [Accepted: 12/14/2015] [Indexed: 12/19/2022]
Abstract
Is nucleotide exchange sufficient to activate K-Ras4B? To signal, oncogenic rat sarcoma (Ras) anchors in the membrane and recruits effectors by exposing its effector lobe. With the use of NMR and molecular dynamics (MD) simulations, we observed that in solution, farnesylated guanosine 5'-diphosphate (GDP)-bound K-Ras4B is predominantly autoinhibited by its hypervariable region (HVR), whereas the GTP-bound state favors an activated, HVR-released state. On the anionic membrane, the catalytic domain adopts multiple orientations, including parallel (∼180°) and perpendicular (∼90°) alignments of the allosteric helices, with respect to the membrane surface direction. In the autoinhibited state, the HVR is sandwiched between the effector lobe and the membrane; in the active state, with membrane-anchored farnesyl and unrestrained HVR, the catalytic domain fluctuates reinlessly, exposing its effector-binding site. Dimerization and clustering can reduce the fluctuations. This achieves preorganized, productive conformations. Notably, we also observe HVR-autoinhibited K-Ras4B-GTP states, with GDP-bound-like orientations of the helices. Thus, we propose that the GDP/GTP exchange may not be sufficient for activation; instead, our results suggest that the GDP/GTP exchange, HVR sequestration, farnesyl insertion, and orientation/localization of the catalytic domain at the membrane conjointly determine the active or inactive state of K-Ras4B. Importantly, K-Ras4B-GTP can exist in active and inactive states; on its own, GTP binding may not compel K-Ras4B activation.-Jang, H., Banerjee, A., Chavan, T. S, Lu, S., Zhang, J., Gaponenko, V., Nussinov, R. The higher level of complexity of K-Ras4B activation at the membrane.
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Affiliation(s)
- Hyunbum Jang
- *Basic Science Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Cancer and Inflammation Program, National Cancer Institute at Frederick, Frederick, Maryland, USA; Department of Chemistry, Department of Medicinal Chemistry, and Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois, USA; Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis, Chinese Ministry of Education, Shanghai JiaoTong University, School of Medicine, Shanghai, China; and Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Avik Banerjee
- *Basic Science Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Cancer and Inflammation Program, National Cancer Institute at Frederick, Frederick, Maryland, USA; Department of Chemistry, Department of Medicinal Chemistry, and Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois, USA; Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis, Chinese Ministry of Education, Shanghai JiaoTong University, School of Medicine, Shanghai, China; and Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Tanmay S Chavan
- *Basic Science Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Cancer and Inflammation Program, National Cancer Institute at Frederick, Frederick, Maryland, USA; Department of Chemistry, Department of Medicinal Chemistry, and Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois, USA; Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis, Chinese Ministry of Education, Shanghai JiaoTong University, School of Medicine, Shanghai, China; and Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Shaoyong Lu
- *Basic Science Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Cancer and Inflammation Program, National Cancer Institute at Frederick, Frederick, Maryland, USA; Department of Chemistry, Department of Medicinal Chemistry, and Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois, USA; Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis, Chinese Ministry of Education, Shanghai JiaoTong University, School of Medicine, Shanghai, China; and Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Jian Zhang
- *Basic Science Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Cancer and Inflammation Program, National Cancer Institute at Frederick, Frederick, Maryland, USA; Department of Chemistry, Department of Medicinal Chemistry, and Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois, USA; Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis, Chinese Ministry of Education, Shanghai JiaoTong University, School of Medicine, Shanghai, China; and Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Vadim Gaponenko
- *Basic Science Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Cancer and Inflammation Program, National Cancer Institute at Frederick, Frederick, Maryland, USA; Department of Chemistry, Department of Medicinal Chemistry, and Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois, USA; Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis, Chinese Ministry of Education, Shanghai JiaoTong University, School of Medicine, Shanghai, China; and Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
| | - Ruth Nussinov
- *Basic Science Program, Leidos Biomedical Research, Frederick National Laboratory for Cancer Research, Cancer and Inflammation Program, National Cancer Institute at Frederick, Frederick, Maryland, USA; Department of Chemistry, Department of Medicinal Chemistry, and Department of Biochemistry and Molecular Genetics, University of Illinois at Chicago, Chicago, Illinois, USA; Department of Pathophysiology, Key Laboratory of Cell Differentiation and Apoptosis, Chinese Ministry of Education, Shanghai JiaoTong University, School of Medicine, Shanghai, China; and Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, Israel
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18
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Li ZL, Ding HM, Ma YQ. Interaction of peptides with cell membranes: insights from molecular modeling. JOURNAL OF PHYSICS. CONDENSED MATTER : AN INSTITUTE OF PHYSICS JOURNAL 2016; 28:083001. [PMID: 26828575 DOI: 10.1088/0953-8984/28/8/083001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
The investigation of the interaction of peptides with cell membranes is the focus of active research. It can enhance the understanding of basic membrane functions such as membrane transport, fusion, and signaling processes, and it may shed light on potential applications of peptides in biomedicine. In this review, we will present current advances in computational studies on the interaction of different types of peptides with the cell membrane. Depending on the properties of the peptide, membrane, and external environment, the peptide-membrane interaction shows a variety of different forms. Here, on the basis of recent computational progress, we will discuss how different peptides could initiate membrane pores, translocate across the membrane, induce membrane endocytosis, produce membrane curvature, form fibrils on the membrane surface, as well as interact with functional membrane proteins. Finally, we will present a conclusion summarizing recent progress and providing some specific insights into future developments in this field.
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Affiliation(s)
- Zhen-lu Li
- National Laboratory of Solid State Microstructures and Department of Physics, Collaborative Innovation Center of Advanced Microstructures, Nanjing University, Nanjing 210093, People's Republic of China
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19
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Medina SH, Miller SE, Keim AI, Gorka AP, Schnermann MJ, Schneider JP. An Intrinsically Disordered Peptide Facilitates Non-Endosomal Cell Entry. Angew Chem Int Ed Engl 2016. [DOI: 10.1002/ange.201510518] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Scott H. Medina
- Chemical Biology Laboratory; National Cancer Institute; National Institutes of Health Fort Detrick; 376 Boyle Street Frederick MD 21702-1201 USA
| | - Stephen E. Miller
- Chemical Biology Laboratory; National Cancer Institute; National Institutes of Health Fort Detrick; 376 Boyle Street Frederick MD 21702-1201 USA
| | - Allison I. Keim
- Chemical Biology Laboratory; National Cancer Institute; National Institutes of Health Fort Detrick; 376 Boyle Street Frederick MD 21702-1201 USA
| | - Alexander P. Gorka
- Chemical Biology Laboratory; National Cancer Institute; National Institutes of Health Fort Detrick; 376 Boyle Street Frederick MD 21702-1201 USA
| | - Martin J. Schnermann
- Chemical Biology Laboratory; National Cancer Institute; National Institutes of Health Fort Detrick; 376 Boyle Street Frederick MD 21702-1201 USA
| | - Joel P. Schneider
- Chemical Biology Laboratory; National Cancer Institute; National Institutes of Health Fort Detrick; 376 Boyle Street Frederick MD 21702-1201 USA
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20
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Medina SH, Miller SE, Keim AI, Gorka AP, Schnermann MJ, Schneider JP. An Intrinsically Disordered Peptide Facilitates Non-Endosomal Cell Entry. Angew Chem Int Ed Engl 2016; 55:3369-72. [PMID: 26835878 DOI: 10.1002/anie.201510518] [Citation(s) in RCA: 49] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2015] [Revised: 12/14/2015] [Indexed: 01/03/2023]
Abstract
Many cell-penetrating peptides (CPPs) fold at cell surfaces, adopting α- or β-structure that enable their intracellular transport. However, the same structural folds that facilitate cellular entry can also elicit potent membrane-lytic activity, limiting their use in delivery applications. Further, a distinct CPP can enter cells through many mechanisms, often leading to endosomal entrapment. Herein, we describe an intrinsically disordered peptide (CLIP6) that exclusively employs non-endosomal mechanisms to cross cellular membranes, while being remarkably biocompatible and serum-stable. We show that a single anionic glutamate residue is responsible for maintaining the disordered bioactive state of the peptide, defines its mechanism of cellular entry, and is central to its biocompatibility. CLIP6 can deliver membrane-impermeable cargo directly to the cytoplasm of cells, suggesting its broad utility for delivery of drug candidates limited by poor cell permeability and endosomal degradation.
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Affiliation(s)
- Scott H Medina
- Chemical Biology Laboratory, National Cancer Institute, National Institutes of Health Fort Detrick, 376 Boyle Street, Frederick, MD, 21702-1201, USA
| | - Stephen E Miller
- Chemical Biology Laboratory, National Cancer Institute, National Institutes of Health Fort Detrick, 376 Boyle Street, Frederick, MD, 21702-1201, USA
| | - Allison I Keim
- Chemical Biology Laboratory, National Cancer Institute, National Institutes of Health Fort Detrick, 376 Boyle Street, Frederick, MD, 21702-1201, USA
| | - Alexander P Gorka
- Chemical Biology Laboratory, National Cancer Institute, National Institutes of Health Fort Detrick, 376 Boyle Street, Frederick, MD, 21702-1201, USA
| | - Martin J Schnermann
- Chemical Biology Laboratory, National Cancer Institute, National Institutes of Health Fort Detrick, 376 Boyle Street, Frederick, MD, 21702-1201, USA
| | - Joel P Schneider
- Chemical Biology Laboratory, National Cancer Institute, National Institutes of Health Fort Detrick, 376 Boyle Street, Frederick, MD, 21702-1201, USA.
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21
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Chulkov EG, Ostroumova OS. Phloretin modulates the rate of channel formation by polyenes. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:289-94. [DOI: 10.1016/j.bbamem.2015.12.004] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Revised: 11/05/2015] [Accepted: 12/01/2015] [Indexed: 12/12/2022]
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22
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Jang H, Arce FT, Lee J, Gillman AL, Ramachandran S, Kagan BL, Lal R, Nussinov R. Computational Methods for Structural and Functional Studies of Alzheimer's Amyloid Ion Channels. Methods Mol Biol 2016; 1345:251-68. [PMID: 26453217 PMCID: PMC7511997 DOI: 10.1007/978-1-4939-2978-8_16] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Aggregation can be studied by a range of methods, experimental and computational. Aggregates form in solution, across solid surfaces, and on and in the membrane, where they may assemble into unregulated leaking ion channels. Experimental probes of ion channel conformations and dynamics are challenging. Atomistic molecular dynamics (MD) simulations are capable of providing insight into structural details of amyloid ion channels in the membrane at a resolution not achievable experimentally. Since data suggest that late stage Alzheimer's disease involves formation of toxic ion channels, MD simulations have been used aiming to gain insight into the channel shapes, morphologies, pore dimensions, conformational heterogeneity, and activity. These can be exploited for drug discovery. Here we describe computational methods to model amyloid ion channels containing the β-sheet motif at atomic scale and to calculate toxic pore activity in the membrane.
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Affiliation(s)
- Hyunbum Jang
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, 1050 Boyles Street, Frederick, MD, 21702, USA.
| | - Fernando Teran Arce
- Department of Bioengineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
- Department of Mechanical and Aerospace Engineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Joon Lee
- Department of Mechanical and Aerospace Engineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Alan L Gillman
- Department of Bioengineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Srinivasan Ramachandran
- Department of Bioengineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
- Department of Mechanical and Aerospace Engineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Bruce L Kagan
- Department of Psychiatry, David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, CA, 90024, USA
| | - Ratnesh Lal
- Department of Bioengineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
- Department of Mechanical and Aerospace Engineering, Materials Science Program, University of California, San Diego, La Jolla, CA, 92093, USA
| | - Ruth Nussinov
- Cancer and Inflammation Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, National Cancer Institute at Frederick, 1050 Boyles Street, Frederick, MD, 21702, USA.
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv, 69978, Israel.
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23
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Ganesan SJ, Xu H, Matysiak S. Effect of lipid head group interactions on membrane properties and membrane-induced cationic β-hairpin folding. Phys Chem Chem Phys 2016; 18:17836-50. [DOI: 10.1039/c5cp07669b] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/07/2023]
Abstract
Stages in membrane induced SVS-1 folding.
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Affiliation(s)
- Sai J. Ganesan
- Fischell Department of Bioengineering
- University of Maryland
- College Park
- USA
| | - Hongcheng Xu
- Biophysics Program
- University of Maryland
- College Park
- USA
| | - Silvina Matysiak
- Fischell Department of Bioengineering
- University of Maryland
- College Park
- USA
- Biophysics Program
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24
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Gupta K, Afonin KA, Viard M, Herrero V, Kasprzak W, Kagiampakis I, Kim T, Koyfman AY, Puri A, Stepler M, Sappe A, KewalRamani VN, Grinberg S, Linder C, Heldman E, Blumenthal R, Shapiro BA. Bolaamphiphiles as carriers for siRNA delivery: From chemical syntheses to practical applications. J Control Release 2015; 213:142-151. [PMID: 26151705 PMCID: PMC4699870 DOI: 10.1016/j.jconrel.2015.06.041] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2015] [Revised: 06/01/2015] [Accepted: 06/29/2015] [Indexed: 12/15/2022]
Abstract
In this study we have investigated a new class of cationic lipids--"bolaamphiphiles" or "bolas"--for their ability to efficiently deliver small interfering RNAs (siRNAs) to cancer cells. The bolas of this study consist of a hydrophobic chain with one or more positively charged head groups at each end. Recently, we reported that micelles of the bolas GLH-19 and GLH-20 (derived from vernonia oil) efficiently deliver siRNAs, while having relatively low toxicities in vitro and in vivo. Our previous studies validated that; bolaamphiphiles can be designed to vary the magnitude of siRNA shielding, its delivery, and its subsequent release. To further understand the structural features of bolas critical for siRNAs delivery, new structurally related bolas (GLH-58 and GLH-60) were designed and synthesized from jojoba oil. Both bolas have similar hydrophobic domains and contain either one, in GLH-58, or two, in GLH-60 positively charged head groups at each end of the hydrophobic core. We have computationally predicted and experimentally validated that GLH-58 formed more stable nano sized micelles than GLH-60 and performed significantly better in comparison to GLH-60 for siRNA delivery. GLH-58/siRNA complexes demonstrated better efficiency in silencing the expression of the GFP gene in human breast cancer cells at concentrations of 5μg/mL, well below the toxic dose. Moreover, delivery of multiple different siRNAs targeting the HIV genome demonstrated further inhibition of virus production.
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Affiliation(s)
- Kshitij Gupta
- Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA; Department of Inorganic and Physical Chemistry, Indian Institute of Science, Bangalore, 560012, India
| | - Kirill A Afonin
- Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA; Department of Chemistry, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, USA
| | - Mathias Viard
- Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA; Basic Science Program, Leidos Biomedical Research Inc., Frederick National Laboratory, Frederick, MD 21702, USA
| | - Virginia Herrero
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Wojciech Kasprzak
- Basic Science Program, Leidos Biomedical Research Inc., Frederick National Laboratory, Frederick, MD 21702, USA
| | - Ioannis Kagiampakis
- HIV Drug Resistance Program, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Taejin Kim
- Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Alexey Y Koyfman
- National Center for Macromolecular Imaging, Verna and Marrs McLean Department of Biochemistry and Molecular Biology, Baylor College of Medicine, Houston, TX 77030, USA
| | - Anu Puri
- Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Marissa Stepler
- Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Alison Sappe
- Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Vineet N KewalRamani
- Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Sarina Grinberg
- Department of Chemistry, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Charles Linder
- Department of Biotechnology, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Eliahu Heldman
- Department of Clinical Biochemistry and Pharmacology, Faculty of Health Sciences, Ben-Gurion University of the Negev, Beer Sheva, Israel
| | - Robert Blumenthal
- Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA
| | - Bruce A Shapiro
- Gene Regulation and Chromosome Biology Laboratory, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702, USA.
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25
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Gupta K, Mattingly SJ, Knipp RJ, Afonin KA, Viard M, Bergman JT, Stepler M, Nantz MH, Puri A, Shapiro BA. Oxime ether lipids containing hydroxylated head groups are more superior siRNA delivery agents than their nonhydroxylated counterparts. Nanomedicine (Lond) 2015; 10:2805-18. [PMID: 26107486 PMCID: PMC4636123 DOI: 10.2217/nnm.15.105] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
AIM To evaluate the structure-activity relationship of oxime ether lipids (OELs) containing modifications in the hydrophobic domains (chain length, degree of unsaturation) and hydrophilic head groups (polar domain hydroxyl groups) toward complex formation with siRNA molecules and siRNA delivery efficiency of resulting complexes to a human breast cancer cell line (MDA-MB-231). MATERIALS & METHODS Ability of lipoplex formation between oxime ether lipids with nucleic acids were examined using biophysical techniques. The potential of OELs to deliver nucleic acids and silence green fluorescent protein (GFP) gene was analyzed using MDA-MB-231 and MDA-MB-231/GFP cells, respectively. RESULTS & CONCLUSION Introduction of hydroxyl groups to the polar domain of the OELs and unsaturation into the hydrophobic domain favor higher transfection and gene silencing in a cell culture system.
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Affiliation(s)
- Kshitij Gupta
- Gene Regulation & Chromosome Biology Lab, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | | | - Ralph J Knipp
- Department of Chemistry, University of Louisville, Louisville, KY 40292, USA
| | - Kirill A Afonin
- Gene Regulation & Chromosome Biology Lab, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
- Department of Chemistry, University of North Carolina at Charlotte, 9201 University City Boulevard, Charlotte, NC 28223, USA
| | - Mathias Viard
- Basic Research Lab, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
- Basic Science Program, Leidos Biomedical Research, Inc., National Cancer Institute, Center for Cancer Research, Frederick National Laboratory for Cancer Research, Frederick, MD 21702-1201, USA
| | - Joseph T Bergman
- Gene Regulation & Chromosome Biology Lab, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Marissa Stepler
- Gene Regulation & Chromosome Biology Lab, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Michael H Nantz
- Department of Chemistry, University of Louisville, Louisville, KY 40292, USA
| | - Anu Puri
- Gene Regulation & Chromosome Biology Lab, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
| | - Bruce A Shapiro
- Gene Regulation & Chromosome Biology Lab, Center for Cancer Research, National Cancer Institute, Frederick, MD 21702-1201, USA
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26
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Jang H, Abraham SJ, Chavan TS, Hitchinson B, Khavrutskii L, Tarasova NI, Nussinov R, Gaponenko V. Mechanisms of membrane binding of small GTPase K-Ras4B farnesylated hypervariable region. J Biol Chem 2015; 290:9465-77. [PMID: 25713064 PMCID: PMC4392252 DOI: 10.1074/jbc.m114.620724] [Citation(s) in RCA: 90] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/22/2014] [Revised: 02/19/2015] [Indexed: 01/08/2023] Open
Abstract
K-Ras4B belongs to a family of small GTPases that regulates cell growth, differentiation and survival. K-ras is frequently mutated in cancer. K-Ras4B association with the plasma membrane through its farnesylated and positively charged C-terminal hypervariable region (HVR) is critical to its oncogenic function. However, the structural mechanisms of membrane association are not fully understood. Here, using confocal microscopy, surface plasmon resonance, and molecular dynamics simulations, we observed that K-Ras4B can be distributed in rigid and loosely packed membrane domains. Its membrane binding domain interaction with phospholipids is driven by membrane fluidity. The farnesyl group spontaneously inserts into the disordered lipid microdomains, whereas the rigid microdomains restrict the farnesyl group penetration. We speculate that the resulting farnesyl protrusion toward the cell interior allows oligomerization of the K-Ras4B membrane binding domain in rigid microdomains. Unlike other Ras isoforms, K-Ras4B HVR contains a single farnesyl modification and positively charged polylysine sequence. The high positive charge not only modulates specific HVR binding to anionic phospholipids but farnesyl membrane orientation. Phosphorylation of Ser-181 prohibits spontaneous farnesyl membrane insertion. The mechanism illuminates the roles of HVR modifications in K-Ras4B targeting microdomains of the plasma membrane and suggests an additional function for HVR in regulation of Ras signaling.
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Affiliation(s)
- Hyunbum Jang
- From the Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research and Cancer and Inflammation Program, NCI-Frederick, National Institutes of Health, Frederick, Maryland 21702
| | - Sherwin J Abraham
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, Departments of Biochemistry and Molecular Genetics and
| | - Tanmay S Chavan
- Department of Molecular and Cellular Physiology, Stanford University, Stanford, California 94305, Medicinal Chemistry, University of Illinois, Chicago, Illinois 60607, and
| | | | - Lyuba Khavrutskii
- From the Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research and Cancer and Inflammation Program, NCI-Frederick, National Institutes of Health, Frederick, Maryland 21702
| | - Nadya I Tarasova
- Cancer and Inflammation Program, NCI-Frederick, National Institutes of Health, Frederick, Maryland 21702,
| | - Ruth Nussinov
- From the Basic Science Program, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research and Cancer and Inflammation Program, NCI-Frederick, National Institutes of Health, Frederick, Maryland 21702, Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Vadim Gaponenko
- Departments of Biochemistry and Molecular Genetics and Medicinal Chemistry, University of Illinois, Chicago, Illinois 60607, and
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27
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Miller Y, Ma B, Nussinov R. Polymorphism in self-assembly of peptide-based β-hairpin contributes to network morphology and hydrogel mechanical rigidity. J Phys Chem B 2015; 119:482-90. [PMID: 25545881 PMCID: PMC4298354 DOI: 10.1021/jp511485n] [Citation(s) in RCA: 33] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2014] [Revised: 12/24/2014] [Indexed: 12/18/2022]
Abstract
Hydrogels are proving to be an excellent class of materials for biomedical applications. The molecular self-assembly of designed MAX1 β-hairpin peptides into fibrillar networks has emerged as a novel route to form responsive hydrogels. Herein, computational modeling techniques are used to investigate the relative arrangements of individual hairpins within the fibrils that constitute the gel. The modeling provides insight into the morphology of the fibril network, which defines the gel's mechanical properties. Our study suggests polymorphic arrangements of the hairpins within the fibrils; however, the relative populations and the relative conformational energies of the polymorphic arrangements show a preference toward an arrangement of hairpins where their turn regions are not capable of forming intermolecular interaction. Repulsive intramolecular electrostatic interactions appear to dictate the formation of fibrils with shorter, rather than longer, persistent lengths. These repulsive intramolecular interactions also disfavor the formation of fibril entanglements. Taken together, the modeling predicts that MAX1 forms a network containing a large number of branch points, a network morphology supported by the formation of short fibril segments. We posit that, under static conditions, the preferred branched structures of the MAX1 peptide assembly result in a cross-linked hydrogel organization. At the same time, the shear stress leads to short fibrillar structures, thus fluidic hydrogel states.
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Affiliation(s)
- Yifat Miller
- Department
of Chemistry and Ilse Katz Institute for Nanoscale Science
and Technology, Ben-Gurion University of
the Negev, Beér-Sheva 84105, Israel
| | - Buyong Ma
- Basic
Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation
Program, National Cancer Institute, Frederick, Maryland 21702, United States
| | - Ruth Nussinov
- Basic
Science Program, Leidos Biomedical Research, Inc. Cancer and Inflammation
Program, National Cancer Institute, Frederick, Maryland 21702, United States
- Sackler
Institute of Molecular Medicine, Department of Human Genetics and
Molecular Medicine, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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28
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Sine J, Urban C, Thayer D, Charron H, Valim N, Tata DB, Schiff R, Blumenthal R, Joshi A, Puri A. Photo activation of HPPH encapsulated in "Pocket" liposomes triggers multiple drug release and tumor cell killing in mouse breast cancer xenografts. Int J Nanomedicine 2014; 10:125-45. [PMID: 25565809 PMCID: PMC4278788 DOI: 10.2147/ijn.s72143] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
We recently reported laser-triggered release of photosensitive compounds from liposomes containing dipalmitoylphosphatidylcholine (DPPC) and 1,2 bis(tricosa-10,12-diynoyl)-sn-glycero-3-phosphocholine (DC(8,9)PC). We hypothesized that the permeation of photoactivated compounds occurs through domains of enhanced fluidity in the liposome membrane and have thus called them "Pocket" liposomes. In this study we have encapsulated the red light activatable anticancer photodynamic therapy drug 2-(1-Hexyloxyethyl)-2-devinyl pyropheophorbide-a (HPPH) (Ex/Em410/670 nm) together with calcein (Ex/Em490/517 nm) as a marker for drug release in Pocket liposomes. A mole ratio of 7.6:1 lipid:HPPH was found to be optimal, with >80% of HPPH being included in the liposomes. Exposure of liposomes with a cw-diode 660 nm laser (90 mW, 0-5 minutes) resulted in calcein release only when HPPH was included in the liposomes. Further analysis of the quenching ratios of liposome-entrapped calcein in the laser treated samples indicated that the laser-triggered release occurred via the graded mechanism. In vitro studies with MDA-MB-231-LM2 breast cancer cell line showed significant cell killing upon treatment of cell-liposome suspensions with the laser. To assess in vivo efficacy, we implanted MDA-MB-231-LM2 cells containing the luciferase gene along the mammary fat pads on the ribcage of mice. For biodistribution experiments, trace amounts of a near infrared lipid probe DiR (Ex/Em745/840 nm) were included in the liposomes. Liposomes were injected intravenously and laser treatments (90 mW, 0.9 cm diameter, for an exposure duration ranging from 5-8 minutes) were done 4 hours postinjection (only one tumor per mouse was treated, keeping the second flank tumor as control). Calcein release occurred as indicated by an increase in calcein fluorescence from laser treated tumors only. The animals were observed for up to 15 days postinjection and tumor volume and luciferase expression was measured. A significant decrease in luciferase expression and reduction in tumor volume was observed only in laser treated animal groups injected with liposomes containing HPPH. Histopathological examination of tumor tissues indicated tumor necrosis resulting from laser treatment of the HPPH-encapsulated liposomes that were taken up into the tumor area.
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Affiliation(s)
- Jessica Sine
- Membrane Structure and Function Section, Basic Research Laboratory, Center for Cancer Research, National Cancer Institute - Frederick, Frederick, MD, USA
| | - Cordula Urban
- Department of Radiology, Baylor College of Medicine, Houston, TX, USA
| | - Derek Thayer
- Membrane Structure and Function Section, Basic Research Laboratory, Center for Cancer Research, National Cancer Institute - Frederick, Frederick, MD, USA
| | - Heather Charron
- Department of Radiology, Baylor College of Medicine, Houston, TX, USA
| | - Niksa Valim
- Department of Radiology, Baylor College of Medicine, Houston, TX, USA
| | - Darrell B Tata
- US Food and Drug Administration, CDRH/OSEL/Division of Physics, White Oak Campus, MD, USA
| | - Rachel Schiff
- Lester and Sue Smith Breast Center, Baylor College of Medicine, Houston, TX, USA
| | - Robert Blumenthal
- Membrane Structure and Function Section, Basic Research Laboratory, Center for Cancer Research, National Cancer Institute - Frederick, Frederick, MD, USA
| | - Amit Joshi
- Department of Radiology, Baylor College of Medicine, Houston, TX, USA
| | - Anu Puri
- Membrane Structure and Function Section, Basic Research Laboratory, Center for Cancer Research, National Cancer Institute - Frederick, Frederick, MD, USA
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29
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Jang H, Arce FT, Ramachandran S, Kagan BL, Lal R, Nussinov R. Disordered amyloidogenic peptides may insert into the membrane and assemble into common cyclic structural motifs. Chem Soc Rev 2014; 43:6750-64. [PMID: 24566672 PMCID: PMC4143503 DOI: 10.1039/c3cs60459d] [Citation(s) in RCA: 72] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Aggregation of disordered amyloidogenic peptides into oligomers is the causative agent of amyloid-related diseases. In solution, disordered protein states are characterized by heterogeneous ensembles. Among these, β-rich conformers self-assemble via a conformational selection mechanism to form energetically-favored cross-β structures, regardless of their precise sequences. These disordered peptides can also penetrate the membrane, and electrophysiological data indicate that they form ion-conducting channels. Based on these and additional data, including imaging and molecular dynamics simulations of a range of amyloid peptides, Alzheimer's amyloid-β (Aβ) peptide, its disease-related variants with point mutations and N-terminal truncated species, other amyloidogenic peptides, as well as a cytolytic peptide and a synthetic gel-forming peptide, we suggest that disordered amyloidogenic peptides can also present a common motif in the membrane. The motif consists of curved, moon-like β-rich oligomers associated into annular organizations. The motif is favored in the lipid bilayer since it permits hydrophobic side chains to face and interact with the membrane and the charged/polar residues to face the solvated channel pores. Such channels are toxic since their pores allow uncontrolled leakage of ions into/out of the cell, destabilizing cellular ionic homeostasis. Here we detail Aβ, whose aggregation is associated with Alzheimer's disease (AD) and for which there are the most abundant data. AD is a protein misfolding disease characterized by a build-up of Aβ peptide as senile plaques, neurodegeneration, and memory loss. Excessively produced Aβ peptides may directly induce cellular toxicity, even without the involvement of membrane receptors through Aβ peptide-plasma membrane interactions.
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Affiliation(s)
- Hyunbum Jang
- Cancer and Inflammation Program, National Cancer Institute at Frederick, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, U.S.A
| | - Fernando Teran Arce
- Departments of Bioengineering and of Mechanical and Aerospace Engineering, and Materials Science Program, University of California, San Diego, La Jolla, California 92093, U.S.A
| | - Srinivasan Ramachandran
- Departments of Bioengineering and of Mechanical and Aerospace Engineering, and Materials Science Program, University of California, San Diego, La Jolla, California 92093, U.S.A
| | - Bruce L. Kagan
- Department of Psychiatry, David Geffen School of Medicine, Semel Institute for Neuroscience and Human Behavior, University of California, Los Angeles, California 90024, U.S.A
| | - Ratnesh Lal
- Departments of Bioengineering and of Mechanical and Aerospace Engineering, and Materials Science Program, University of California, San Diego, La Jolla, California 92093, U.S.A
| | - Ruth Nussinov
- Cancer and Inflammation Program, National Cancer Institute at Frederick, Leidos Biomedical Research, Inc., Frederick National Laboratory for Cancer Research, Frederick, Maryland 21702, U.S.A
- Department of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
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30
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Gillman AL, Jang H, Lee J, Ramachandran S, Kagan B, Nussinov R, Teran Arce F. Activity and architecture of pyroglutamate-modified amyloid-β (AβpE3-42) pores. J Phys Chem B 2014; 118:7335-44. [PMID: 24922585 PMCID: PMC4096221 DOI: 10.1021/jp5040954] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2014] [Revised: 06/10/2014] [Indexed: 12/17/2022]
Abstract
Among the family of Aβ peptides, pyroglutamate-modified Aβ (AβpE) peptides are particularly associated with cytotoxicity in Alzheimer's disease (AD). They represent the dominant fraction of Aβ oligomers in the brains of AD patients, but their accumulation in the brains of elderly individuals with normal cognition is significantly lower. Accumulation of AβpE plaques precedes the formation of plaques of full-length Aβ (Aβ1-40/42). Most of these properties appear to be associated with the higher hydrophobicity of AβpE as well as an increased resistance to enzymatic degradation. However, the important question of whether AβpE peptides induce pore activity in lipid membranes and their potential toxicity compared with other Aβ pores is still open. Here we examine the activity of AβpE pores in anionic membranes using planar bilayer electrical recording and provide their structures using molecular dynamics simulations. We find that AβpE pores spontaneously induce ionic current across the membrane and have some similar properties to the other previously studied pores of the Aβ family. However, there are also some significant differences. The onset of AβpE3-42 pore activity is generally delayed compared with Aβ1-42 pores. However, once formed, AβpE3-42 pores produce increased ion permeability of the membrane, as indicated by a greater occurrence of higher conductance electrical events. Structurally, the lactam ring of AβpE peptides induces a change in the conformation of the N-terminal strands of the AβpE3-42 pores. While the N-termini of wild-type Aβ1-42 peptides normally reside in the bulk water region, the N-termini of AβpE3-42 peptides tend to reside in the hydrophobic lipid core. These studies provide a first step to an understanding of the enhanced toxicity attributed to AβpE peptides.
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Affiliation(s)
- Alan L. Gillman
- Department
of Bioengineering, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
| | - Hyunbum Jang
- Cancer
and Inflammation Program, National Cancer Institute at Frederick,
Leidos Biomedical Research, Inc., Frederick
National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
| | - Joon Lee
- Department
of Mechanical and Aerospace Engineering and Material Science Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Srinivasan Ramachandran
- Department
of Bioengineering, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
- Department
of Mechanical and Aerospace Engineering and Material Science Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
| | - Bruce
L. Kagan
- Department
of Psychiatry, David Geffen School of Medicine, Semel Institute for
Neuroscience and Human Behavior, University
of California, 760 Westwood
Plaza, Los Angeles, California 90024, United States
| | - Ruth Nussinov
- Cancer
and Inflammation Program, National Cancer Institute at Frederick,
Leidos Biomedical Research, Inc., Frederick
National Laboratory for Cancer Research, Frederick, Maryland 21702, United States
- Department
of Human Molecular Genetics and Biochemistry, Sackler School of Medicine, Tel Aviv University, Tel Aviv 69978, Israel
| | - Fernando Teran Arce
- Department
of Bioengineering, University of California,
San Diego, 9500 Gilman
Drive, La Jolla, California 92093, United States
- Department
of Mechanical and Aerospace Engineering and Material Science Program, University of California, San Diego, 9500 Gilman Drive, La Jolla, California 92093, United States
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31
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Morriss-Andrews A, Brown FLH, Shea JE. A coarse-grained model for peptide aggregation on a membrane surface. J Phys Chem B 2014; 118:8420-32. [PMID: 24791936 DOI: 10.1021/jp502871m] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The aggregation of peptides on a lipid bilayer is studied using coarse-grained molecular dynamics in implicit solvent. Peptides bind to and self-assemble on the membrane surface into β-rich fibrillar aggregates, even under conditions where only disordered oligomers form in bulk solution. Relative to a solid surface, the membrane surface facilitates peptide mobility and a more complex network of morphology transitions as aggregation proceeds. Additionally, final aggregate structures realized on the membrane surface are distinct from those observed on a comparable solid surface. The aggregated fibrils alter the local structure and material properties of the lipid bilayer in their immediate vicinity but have only a modest effect on the overall bending rigidity of the bilayer.
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Affiliation(s)
- Alex Morriss-Andrews
- Department of Physics, University of California Santa Barbara , Santa Barbara, California 93106, United States
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