1
|
Roy R, Chick P, York E, Rawling T. Cytotoxicity of acridinium-based ionic liquids: Structure-activity relationship and mechanistic studies. Chem Biol Interact 2024; 396:111042. [PMID: 38735455 DOI: 10.1016/j.cbi.2024.111042] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 04/25/2024] [Accepted: 05/05/2024] [Indexed: 05/14/2024]
Abstract
Ionic liquids (ILs) are a class of low melting point salts with physicochemical properties suitable for a range of industrial applications such as chemical processing and battery design. Major challenges to the wide-scale adoption of ILs in industry include their eco- and cytotoxic effects, however, this opens up the possibility of the use of ILs use as novel anticancer agents. Understanding the structural features that promote IL cytotoxicity is therefore important. Key structural features that can impact IL cytotoxicity include size and lipophilicity of the cationic head group. In this study, the cytotoxic effects of acridinium-based ILs containing relatively large tri- and tetracyclic cations were evaluated. It was found that 9-phenylacridinium-based ILs are potent cytotoxic agents that reduce the viability of human MDA-MB-231 breast cancer cells with IC50 concentrations in the nanomolar range. In mechanistic studies, it was found that unlike the pyridinium-based analogue, [C16Py][I], acridinium-based ILs did not inhibit oxidative phosphorylation or induce reactive oxygen species formation, and may instead target other mitochondrial processes or components such as mitochondrial DNA.
Collapse
Affiliation(s)
- Ritik Roy
- School of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Phoenix Chick
- School of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Edward York
- School of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Tristan Rawling
- School of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, 2007, Australia.
| |
Collapse
|
2
|
Roseli RB, Huang YH, Henriques ST, Kaas Q, Craik DJ. Molecular dynamics simulations support a preference of cyclotide kalata B1 for phosphatidylethanolamine phospholipids. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184268. [PMID: 38191035 DOI: 10.1016/j.bbamem.2023.184268] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/30/2023] [Revised: 12/21/2023] [Accepted: 12/21/2023] [Indexed: 01/10/2024]
Abstract
Kalata B1 (kB1), a naturally occurring cyclotide has been shown experimentally to bind lipid membranes that contain phosphatidylethanolamine (PE) phospholipids. Here, molecular dynamics simulations were used to explore its interaction with two phospholipids, palmitoyloleoylphosphatidylethanolamine (POPE), palmitoyloleoylphosphatidylcholine (POPC), and a heterogeneous membrane comprising POPC/POPE (90:10), to understand the basis for the selectivity of kB1 towards PE phospholipids. The simulations showed that in the presence of only 10 % POPE lipid, kB1 forms a stable binding complex with membrane bilayers. An ionic interaction between the E7 carboxylate group of kB1 and the ammonium group of PE headgroups consistently initiates binding of kB1 to the membrane. Additionally, stable noncovalent interactions such as hydrogen bonding (E7, T8, V10, G11, T13 and N15), cation-π (W23), and CH-π (W23) interactions between specific residues of kB1 and the lipid membrane play an important role in stabilizing the binding. These findings are consistent with a structure-activity relationship study on kB1 where lysine mutagenesis on the bioactive and hydrophobic faces of the peptide abolished membrane-dependent bioactivities. In summary, our simulations suggest the importance of residue E7 (in the bioactive face) in enabling kB1 to recognize and bind selectively to PE-containing phospholipids bilayers through ionic and hydrogen bonding interactions, and of W23 (in the hydrophobic face) for the association and insertion of kB1 into the lipid bilayer through cation-π and CH-π interactions. Overall, this work enhances our understanding of the molecular basis of the membrane binding and bioactivity of this prototypic cyclotide.
Collapse
Affiliation(s)
- Ras Baizureen Roseli
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Yen-Hua Huang
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - Sónia Troeira Henriques
- School of Biomedical Sciences, Queensland University of Technology, Translational Research Institute, Brisbane, QLD 4102, Australia
| | - Quentin Kaas
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia
| | - David J Craik
- Institute for Molecular Bioscience, Australian Research Council Centre of Excellence for Innovations in Peptide and Protein Science, The University of Queensland, Brisbane, Queensland 4072, Australia.
| |
Collapse
|
3
|
Tan SW, Yoon BK, Jackman JA. Membrane-Disruptive Effects of Fatty Acid and Monoglyceride Mitigants on E. coli Bacteria-Derived Tethered Lipid Bilayers. Molecules 2024; 29:237. [PMID: 38202820 PMCID: PMC10780109 DOI: 10.3390/molecules29010237] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2023] [Revised: 12/23/2023] [Accepted: 12/26/2023] [Indexed: 01/12/2024] Open
Abstract
We report electrochemical impedance spectroscopy measurements to characterize the membrane-disruptive properties of medium-chain fatty acid and monoglyceride mitigants interacting with tethered bilayer lipid membrane (tBLM) platforms composed of E. coli bacterial lipid extracts. The tested mitigants included capric acid (CA) and monocaprin (MC) with 10-carbon long hydrocarbon chains, and lauric acid (LA) and glycerol monolaurate (GML) with 12-carbon long hydrocarbon chains. All four mitigants disrupted E. coli tBLM platforms above their respective critical micelle concentration (CMC) values; however, there were marked differences in the extent of membrane disruption. In general, CA and MC caused larger changes in ionic permeability and structural damage, whereas the membrane-disruptive effects of LA and GML were appreciably smaller. Importantly, the distinct magnitudes of permeability changes agreed well with the known antibacterial activity levels of the different mitigants against E. coli, whereby CA and MC are inhibitory and LA and GML are non-inhibitory. Mechanistic insights obtained from the EIS data help to rationalize why CA and MC are more effective than LA and GML at disrupting E. coli membranes, and these measurement capabilities support the potential of utilizing bacterial lipid-derived tethered lipid bilayers for predictive assessment of antibacterial drug candidates and mitigants.
Collapse
Affiliation(s)
- Sue Woon Tan
- School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Bo Kyeong Yoon
- School of Healthcare and Biomedical Engineering, Chonnam National University, Yeosu 59626, Republic of Korea
| | - Joshua A. Jackman
- School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
| |
Collapse
|
4
|
Roy R, York E, Pacchini E, Rawling T. Effects of cationic head group structure on cytotoxicity and mitochondrial actions of amphiphilic ionic liquids. Food Chem Toxicol 2024; 183:114202. [PMID: 38007213 DOI: 10.1016/j.fct.2023.114202] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 10/24/2023] [Accepted: 11/17/2023] [Indexed: 11/27/2023]
Abstract
Ionic liquids (ILs) are a class of low melting point salts with physicochemical properties that make them suitable for a range of industrial applications. Accumulating evidence suggests that certain ILs are cytotoxic and potential environmental pollutants, thus understanding the structural features that promote IL cytotoxicity is important. Amphiphilic ionic liquids (AmILs), a class of ILs with lipophilic N-alkyl chains, containing aromatic head groups are generally more cytotoxic than their aliphatic counterparts, however the impact of other head group properties are less clear. This study therefore sought to provide new structure activity relationship (SAR) insights regarding the role of the cationic head group on AmIL cytotoxicity. A series of AmILs bearing a range of structurally diverse aromatic cations varying in size, charge, and lipophilicity was synthesised and screened against human MDA-MB-231 breast cancer cells. It was found that larger and more lipophilic head groups increased cytotoxicity, although the magnitude of the changes were modest. The mitochondrial effects of representative ILs were assessed. The AmILs induced mitochondrial dysfunction in MDA-MB-231 cells at cytotoxic concentrations, suggesting that they target mitochondria. The new SAR information from this study may assist in the design of AmILs with controlled cytotoxicity.
Collapse
Affiliation(s)
- Ritik Roy
- School of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Edward York
- School of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Ethan Pacchini
- School of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, 2007, Australia
| | - Tristan Rawling
- School of Mathematical and Physical Sciences, Faculty of Science, University of Technology Sydney, Sydney, NSW, 2007, Australia.
| |
Collapse
|
5
|
Lankage U, Holt SA, Bridge S, Cornell B, Cranfield CG. Triglyceride-Tethered Membrane Lipase Sensor. ACS APPLIED MATERIALS & INTERFACES 2023; 15. [PMID: 37931023 PMCID: PMC10658451 DOI: 10.1021/acsami.3c11767] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/09/2023] [Revised: 10/09/2023] [Accepted: 10/12/2023] [Indexed: 11/08/2023]
Abstract
Sensors that can quickly measure the lipase activity from biological samples are useful in enzyme production and medical diagnostics. However, current lipase sensors have limitations such as requiring fluorescent labels, pH control of buffer vehicles, or lengthy assay preparation. We introduce a sparsely tethered triglyceride substrate anchored off of a gold electrode for the impedance sensing of real-time lipase activity. The tethered substrate is self-assembled using a rapid solvent exchange technique and can form an anchored bilayer 1 nm off the gold electrode. This allows for an aqueous reservoir region, providing access to ions transported through membrane defects caused by triglyceride enzymatic hydrolysis. Electrical impedance spectroscopy techniques can readily detect the decrease in resistance caused by enzymatically induced defects. This rapid and reliable lipase detection method can have potential applications in disease studies, monitoring of lipase production, and as point-of-care diagnostic devices.
Collapse
Affiliation(s)
| | - Stephen A. Holt
- School
of Life Sciences, University of Technology
Sydney, Ultimo, NSW 2007, Australia
- Australian
Nuclear Science and Technology Organisation, Lucas Heights, NSW 2234, Australia
| | - Samara Bridge
- School
of Life Sciences, University of Technology
Sydney, Ultimo, NSW 2007, Australia
| | - Bruce Cornell
- School
of Life Sciences, University of Technology
Sydney, Ultimo, NSW 2007, Australia
- SDx
Surgical Diagnostics Pty Ltd., U6 30-32 Barcoo Street, Roseville, NSW 2069, Australia
| | - Charles G. Cranfield
- School
of Life Sciences, University of Technology
Sydney, Ultimo, NSW 2007, Australia
| |
Collapse
|
6
|
Gooran N, Tan SW, Yoon BK, Jackman JA. Unraveling Membrane-Disruptive Properties of Sodium Lauroyl Lactylate and Its Hydrolytic Products: A QCM-D and EIS Study. Int J Mol Sci 2023; 24:ijms24119283. [PMID: 37298235 DOI: 10.3390/ijms24119283] [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: 04/12/2023] [Revised: 05/15/2023] [Accepted: 05/24/2023] [Indexed: 06/12/2023] Open
Abstract
Membrane-disrupting lactylates are an important class of surfactant molecules that are esterified adducts of fatty acid and lactic acid and possess industrially attractive properties, such as high antimicrobial potency and hydrophilicity. Compared with antimicrobial lipids such as free fatty acids and monoglycerides, the membrane-disruptive properties of lactylates have been scarcely investigated from a biophysical perspective, and addressing this gap is important to build a molecular-level understanding of how lactylates work. Herein, using the quartz crystal microbalance-dissipation (QCM-D) and electrochemical impedance spectroscopy (EIS) techniques, we investigated the real-time, membrane-disruptive interactions between sodium lauroyl lactylate (SLL)-a promising lactylate with a 12-carbon-long, saturated hydrocarbon chain-and supported lipid bilayer (SLB) and tethered bilayer lipid membrane (tBLM) platforms. For comparison, hydrolytic products of SLL that may be generated in biological environments, i.e., lauric acid (LA) and lactic acid (LacA), were also tested individually and as a mixture, along with a structurally related surfactant (sodium dodecyl sulfate, SDS). While SLL, LA, and SDS all had equivalent chain properties and critical micelle concentration (CMC) values, our findings reveal that SLL exhibits distinct membrane-disruptive properties that lie in between the rapid, complete solubilizing activity of SDS and the more modest disruptive properties of LA. Interestingly, the hydrolytic products of SLL, i.e., the LA + LacA mixture, induced a greater degree of transient, reversible membrane morphological changes but ultimately less permanent membrane disruption than SLL. These molecular-level insights support that careful tuning of antimicrobial lipid headgroup properties can modulate the spectrum of membrane-disruptive interactions, offering a pathway to design surfactants with tailored biodegradation profiles and reinforcing that SLL has attractive biophysical merits as a membrane-disrupting antimicrobial drug candidate.
Collapse
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
| | - Bo Kyeong Yoon
- School of Healthcare and Biomedical Engineering, Chonnam National University, Yeosu 59626, Republic of Korea
| | - Joshua A Jackman
- School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
| |
Collapse
|
7
|
Tan SW, Gooran N, Lim HM, Yoon BK, Jackman JA. Tethered Bilayer Lipid Membrane Platform for Screening Triton X-100 Detergent Replacements by Electrochemical Impedance Spectroscopy. NANOMATERIALS (BASEL, SWITZERLAND) 2023; 13:874. [PMID: 36903751 PMCID: PMC10005542 DOI: 10.3390/nano13050874] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/04/2023] [Revised: 02/23/2023] [Accepted: 02/25/2023] [Indexed: 06/18/2023]
Abstract
In light of regulatory considerations, there are ongoing efforts to identify Triton X-100 (TX-100) detergent alternatives for use in the biological manufacturing industry to mitigate membrane-enveloped pathogen contamination. Until now, the efficacy of antimicrobial detergent candidates to replace TX-100 has been tested regarding pathogen inhibition in endpoint biological assays or probing lipid membrane disruption in real-time biophysical testing platforms. The latter approach has proven especially useful to test compound potency and mechanism of action, however, existing analytical approaches have been limited to studying indirect effects of lipid membrane disruption such as membrane morphological changes. A direct readout of lipid membrane disruption by TX-100 detergent alternatives would be more practical to obtain biologically relevant information to guide compound discovery and optimization. Herein, we report the use of electrochemical impedance spectroscopy (EIS) to investigate how TX-100 and selected replacement candidates-Simulsol SL 11W (Simulsol) and cetyltrimethyl ammonium bromide (CTAB)-affect the ionic permeability of tethered bilayer lipid membrane (tBLM) platforms. The EIS results revealed that all three detergents exhibited dose-dependent effects mainly above their respective critical micelle concentration (CMC) values while displaying distinct membrane-disruptive behaviors. TX-100 caused irreversible membrane disruption leading to complete solubilization, whereas Simulsol caused reversible membrane disruption and CTAB induced irreversible, partial membrane defect formation. These findings establish that the EIS technique is useful for screening the membrane-disruptive behaviors of TX-100 detergent alternatives with multiplex formatting possibilities, rapid response, and quantitative readouts relevant to antimicrobial functions.
Collapse
Affiliation(s)
- Sue Woon Tan
- School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Negin Gooran
- School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
| | - Hye Min Lim
- School of Healthcare and Biomedical Engineering, Chonnam National University, Yeosu 59626, Republic of Korea
- Interdisciplinary Program of Biomedical Engineering, Chonnam National University, Yeosu 59626, Republic of Korea
| | - Bo Kyeong Yoon
- School of Healthcare and Biomedical Engineering, Chonnam National University, Yeosu 59626, Republic of Korea
- Interdisciplinary Program of Biomedical Engineering, Chonnam National University, Yeosu 59626, Republic of Korea
| | - Joshua A. Jackman
- School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Republic of Korea
| |
Collapse
|
8
|
Koo DJ, Sut TN, Tan SW, Yoon BK, Jackman JA. Biophysical Characterization of LTX-315 Anticancer Peptide Interactions with Model Membrane Platforms: Effect of Membrane Surface Charge. Int J Mol Sci 2022; 23:10558. [PMID: 36142470 PMCID: PMC9501188 DOI: 10.3390/ijms231810558] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2022] [Revised: 09/06/2022] [Accepted: 09/08/2022] [Indexed: 11/16/2022] Open
Abstract
LTX-315 is a clinical-stage, anticancer peptide therapeutic that disrupts cancer cell membranes. Existing mechanistic knowledge about LTX-315 has been obtained from cell-based biological assays, and there is an outstanding need to directly characterize the corresponding membrane-peptide interactions from a biophysical perspective. Herein, we investigated the membrane-disruptive properties of the LTX-315 peptide using three cell-membrane-mimicking membrane platforms on solid supports, namely the supported lipid bilayer, intact vesicle adlayer, and tethered lipid bilayer, in combination with quartz crystal microbalance-dissipation (QCM-D) and electrochemical impedance spectroscopy (EIS) measurements. The results showed that the cationic LTX-315 peptide selectively disrupted negatively charged phospholipid membranes to a greater extent than zwitterionic or positively charged phospholipid membranes, whereby electrostatic interactions were the main factor to influence peptide attachment and membrane curvature was a secondary factor. Of note, the EIS measurements showed that the LTX-315 peptide extensively and irreversibly permeabilized negatively charged, tethered lipid bilayers that contained high phosphatidylserine lipid levels representative of the outer leaflet of cancer cell membranes, while circular dichroism (CD) spectroscopy experiments indicated that the LTX-315 peptide was structureless and the corresponding membrane-disruptive interactions did not involve peptide conformational changes. Dynamic light scattering (DLS) measurements further verified that the LTX-315 peptide selectively caused irreversible disruption of negatively charged lipid vesicles. Together, our findings demonstrate that the LTX-315 peptide preferentially disrupts negatively charged phospholipid membranes in an irreversible manner, which reinforces its potential as an emerging cancer immunotherapy and offers a biophysical framework to guide future peptide engineering efforts.
Collapse
Affiliation(s)
- Dong Jun Koo
- School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Korea
| | - Tun Naw Sut
- School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Korea
| | - Sue Woon Tan
- School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Korea
| | - Bo Kyeong Yoon
- School of Healthcare and Biomedical Engineering, Chonnam National University, Yeosu 59626, Korea
| | - Joshua A. Jackman
- School of Chemical Engineering and Translational Nanobioscience Research Center, Sungkyunkwan University, Suwon 16419, Korea
| |
Collapse
|
9
|
Conzelmann C, Muratspahić E, Tomašević N, Münch J, Gruber CW. In vitro Inhibition of HIV-1 by Cyclotide-Enriched Extracts of Viola tricolor. Front Pharmacol 2022; 13:888961. [PMID: 35712712 PMCID: PMC9196940 DOI: 10.3389/fphar.2022.888961] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2022] [Accepted: 05/03/2022] [Indexed: 11/13/2022] Open
Abstract
Since viral infectious diseases continue to be a global health threat, new antiviral drugs are urgently needed. A unique class of therapeutic compounds are antimicrobial peptides (AMPs). They can be found in humans, bacteria and plants. Plants express a wide variety of such defense peptides as part of their innate immune system to protect from invading pathogens. Cyclotides are non-classical AMPs that share a similar structure. Their unique topology consists of a circular peptide backbone and disulfide bonds. In previous studies they have been attributed to a wide range of biological activities. To identify novel cyclotides with antiviral activity, we established a library of plant extracts largely consisting of cyclotide-rich species and screened them as inhibitors of HIV-1 infection. Subsequent extraction and fractionation revealed four cyclotide-containing subfractions from Viola tricolor with antiviral activity. These subfractions inhibited HIV-1 infection with IC50 values between 0.6 and 11.2 μg/ml, and selectivity indices of up to 8.1. The identification and characterization of antiviral cyclotides and the determination of the antiviral mechanisms may allow to develop novel agents to combat viral infections. Therefore, cyclotides represent a natural source of bioactive molecules with prospects for development as therapeutics.
Collapse
Affiliation(s)
- Carina Conzelmann
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
| | - Edin Muratspahić
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Nataša Tomašević
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
| | - Jan Münch
- Institute of Molecular Virology, Ulm University Medical Center, Ulm, Germany
- *Correspondence: Jan Münch, ; Christian W. Gruber,
| | - Christian W. Gruber
- Center for Physiology and Pharmacology, Medical University of Vienna, Vienna, Austria
- *Correspondence: Jan Münch, ; Christian W. Gruber,
| |
Collapse
|
10
|
Mechanistic Evaluation of Antimicrobial Lipid Interactions with Tethered Lipid Bilayers by Electrochemical Impedance Spectroscopy. SENSORS 2022; 22:s22103712. [PMID: 35632121 PMCID: PMC9148023 DOI: 10.3390/s22103712] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/16/2022] [Revised: 05/10/2022] [Accepted: 05/10/2022] [Indexed: 01/27/2023]
Abstract
There is extensive interest in developing real-time biosensing strategies to characterize the membrane-disruptive properties of antimicrobial lipids and surfactants. Currently used biosensing strategies mainly focus on tracking membrane morphological changes such as budding and tubule formation, while there is an outstanding need to develop a label-free biosensing strategy to directly evaluate the molecular-level mechanistic details by which antimicrobial lipids and surfactants disrupt lipid membranes. Herein, using electrochemical impedance spectroscopy (EIS), we conducted label-free biosensing measurements to track the real-time interactions between three representative compounds—glycerol monolaurate (GML), lauric acid (LA), and sodium dodecyl sulfate (SDS)—and a tethered bilayer lipid membrane (tBLM) platform. The EIS measurements verified that all three compounds are mainly active above their respective critical micelle concentration (CMC) values, while also revealing that GML induces irreversible membrane damage whereas the membrane-disruptive effects of LA are largely reversible. In addition, SDS micelles caused membrane solubilization, while SDS monomers still caused membrane defect formation, shedding light on how antimicrobial lipids and surfactants can be active in, not only micellar form, but also as monomers in some cases. These findings expand our mechanistic knowledge of how antimicrobial lipids and surfactants disrupt lipid membranes and demonstrate the analytical merits of utilizing the EIS sensing approach to comparatively evaluate membrane-disruptive antimicrobial compounds.
Collapse
|
11
|
Mohid SA, Sharma P, Alghalayini A, Saini T, Datta D, Willcox MD, Ali H, Raha S, Singha A, Lee D, Sahoo N, Cranfield CG, Roy S, Bhunia A. A rationally designed synthetic antimicrobial peptide against Pseudomonas-associated corneal keratitis: Structure-function correlation. Biophys Chem 2022; 286:106802. [DOI: 10.1016/j.bpc.2022.106802] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2022] [Revised: 03/10/2022] [Accepted: 03/15/2022] [Indexed: 11/02/2022]
|
12
|
Gerlach SL, Dunlop RA, Metcalf JS, Banack SA, Cox PA. Cyclotides Chemosensitize Glioblastoma Cells to Temozolomide. JOURNAL OF NATURAL PRODUCTS 2022; 85:34-46. [PMID: 35044783 DOI: 10.1021/acs.jnatprod.1c00595] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
Glioblastoma multiforme (GBM) is the most aggressive cancer originating in the brain, with a median survival of 12 months. Most patients do not respond to or develop resistance to the only effective chemotherapeutic drug, temozolomide (TMZ), used to treat gliomas. Novel treatment methods are critically needed. Cyclotides are plant peptides that may be promising adjuvants to TMZ chemotherapy. They exhibit antitumor activity and chemosensitize cells to doxorubicin in breast cancer studies. During this research, we optimized cyclotide isolation techniques, and several cyclotides (CyO2, CyO13, kalata B1, and varv peptide A) exhibited dose-dependent cytotoxicity in MTT assays with IC50 values of 2.15-7.92 μM against human brain astrocytoma cells (U-87 MG) and human bone marrow derived neuroblastoma cells (SH-SY5Y). CyO2 and varv peptide A increased TMZ-induced cell death in U-87 MG cultures alone and when coexposed with CyO2 or varv peptide A plus TMZ. Phase contrast microscopy of glioblastoma cells exposed to cyclotides alone and coexposed to TMZ indicated shrunken, granular cells with blebbing, and the most pronounced effects were observed with coexposure treatments of cyclotides and TMZ. Cumulative results provide the proof-of-concept that cyclotides may enhance TMZ chemotherapy, and in vivo pharmacokinetic investigations of cyclotides are warranted with respect to GBM.
Collapse
Affiliation(s)
- Samantha L Gerlach
- Department of Biology, Dillard University, New Orleans, Louisiana 70122, United States
| | - Rachael A Dunlop
- Institute for Ethnomedicine, Brain Chemistry Laboratories, Box 3464, Jackson, Wyoming 83001, United States
| | - James S Metcalf
- Institute for Ethnomedicine, Brain Chemistry Laboratories, Box 3464, Jackson, Wyoming 83001, United States
| | - Sandra A Banack
- Institute for Ethnomedicine, Brain Chemistry Laboratories, Box 3464, Jackson, Wyoming 83001, United States
| | - Paul Alan Cox
- Institute for Ethnomedicine, Brain Chemistry Laboratories, Box 3464, Jackson, Wyoming 83001, United States
| |
Collapse
|
13
|
Deplazes E, Tafalla BD, Murphy C, White J, Cranfield CG, Garcia A. Calcium Ion Binding at the Lipid-Water Interface Alters the Ion Permeability of Phospholipid Bilayers. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2021; 37:14026-14033. [PMID: 34784471 DOI: 10.1021/acs.langmuir.1c02016] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
Calcium ions (Ca2+) play a fundamental role in membrane-associated physiological processes. Ca2+ can also significantly modulate the physicochemical properties of phospholipid bilayers, but whether this occurs at physiologically relevant concentrations is difficult to determine because of the uncertainty in the reported affinity of Ca2+ for phospholipid bilayers. In this article, we determine the apparent affinity of Ca2+ for zwitterionic phospholipid bilayers using tethered bilayer lipid membranes (tBLMs) used in conjunction with swept-frequency electrical impedance spectroscopy (EIS). We report that Ca2+ binds to phospholipid bilayers at physiologically relevant concentrations and modulates membrane permeability. We present direct experimental evidence that this effect is governed by specific interactions with select lipid headgroup moieties, which is supported by data from molecular dynamics (MD) simulations. This is the first reported use of tBLM/EIS to estimate cation-membrane affinity. Combined with MD simulations, this technique provides a novel methodology to elucidate the molecular details of cation-membrane interactions at the water-phospholipid interface.
Collapse
Affiliation(s)
- Evelyne Deplazes
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia
- School of Chemistry and Molecular Biosciences, University of Queensland, St Lucia, QLD 4072, Australia
| | | | - Christopher Murphy
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Jacqueline White
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Charles G Cranfield
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia
| | - Alvaro Garcia
- School of Life Sciences, University of Technology Sydney, Ultimo, NSW 2007, Australia
| |
Collapse
|
14
|
Why Do Tethered-Bilayer Lipid Membranes Suit for Functional Membrane Protein Reincorporation? APPLIED SCIENCES-BASEL 2021. [DOI: 10.3390/app11114876] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Membrane proteins (MPs) are essential for cellular functions. Understanding the functions of MPs is crucial as they constitute an important class of drug targets. However, MPs are a challenging class of biomolecules to analyze because they cannot be studied outside their native environment. Their structure, function and activity are highly dependent on the local lipid environment, and these properties are compromised when the protein does not reside in the cell membrane. Mammalian cell membranes are complex and composed of different lipid species. Model membranes have been developed to provide an adequate environment to envisage MP reconstitution. Among them, tethered-Bilayer Lipid Membranes (tBLMs) appear as the best model because they allow the lipid bilayer to be decoupled from the support. Thus, they provide a sufficient aqueous space to envisage the proper accommodation of large extra-membranous domains of MPs, extending outside. Additionally, as the bilayer remains attached to tethers covalently fixed to the solid support, they can be investigated by a wide variety of surface-sensitive analytical techniques. This review provides an overview of the different approaches developed over the last two decades to achieve sophisticated tBLMs, with a more and more complex lipid composition and adapted for functional MP reconstitution.
Collapse
|
15
|
van den Broek K, Epple M, Kersten LS, Kuhn H, Zielesny A. Quantitative Estimation of Cyclotide-Induced Bilayer Membrane Disruption by Lipid Extraction with Mesoscopic Simulation. J Chem Inf Model 2021; 61:3027-3040. [PMID: 34008405 DOI: 10.1021/acs.jcim.1c00332] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Cyclotide-induced membrane disruption is studied at the microsecond timescale by dissipative particle dynamics to quantitatively estimate a kinetic rate constant for membrane lipid extraction with a ″sandwich″ interaction model where two bilayer membranes enclose a cyclotide/water compartment. The obtained bioactivity trends for cyclotides Kalata B1, Cycloviolacin O2, and selected mutants with different membrane types are in agreement with experimental findings: For all membranes investigated, Cycloviolacin O2 shows a higher lipid extraction activity than Kalata B1. The presence of cholesterol leads to a decreased cyclotide activity compared to cholesterol-free membranes. Phosphoethanolamine-rich membranes exhibit an increased membrane disruption. A cyclotide's ″hydrophobic patch″ surface area is important for its bioactivity. A replacement of or with charged amino acid residues may lead to super-mutants with above-native activity but without simple charge-activity patterns. Cyclotide mixtures show linearly additive bioactivities without significant sub- or over-additive effects. The proposed method can be applied as a fast and easy-to-use tool for exploring structure-activity relationships of cyclotide/membrane systems: With the open software provided, the rate constant of a single cyclotide/membrane system can be determined in about 1 day by a scientific end-user without programming skills.
Collapse
Affiliation(s)
- Karina van den Broek
- Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, 45141 Essen, Germany.,Institute for Bioinformatics and Chemoinformatics, Westphalian University of Applied Sciences, 45665 Recklinghausen, Germany
| | - Matthias Epple
- Inorganic Chemistry and Center for Nanointegration Duisburg-Essen (CeNIDE), University of Duisburg-Essen, 45141 Essen, Germany
| | - Lisa Sophie Kersten
- Institute for Bioinformatics and Chemoinformatics, Westphalian University of Applied Sciences, 45665 Recklinghausen, Germany
| | - Hubert Kuhn
- CAM-D Technologies GmbH, 42697 Solingen, Germany
| | - Achim Zielesny
- Institute for Bioinformatics and Chemoinformatics, Westphalian University of Applied Sciences, 45665 Recklinghausen, Germany
| |
Collapse
|
16
|
Soon TN, Chia AYY, Yap WH, Tang YQ. Anticancer Mechanisms of Bioactive Peptides. Protein Pept Lett 2021; 27:823-830. [PMID: 32271692 DOI: 10.2174/0929866527666200409102747] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/21/2020] [Revised: 02/24/2020] [Accepted: 03/04/2020] [Indexed: 02/07/2023]
Abstract
Despite technological advancement, there is no 100% effective treatment against metastatic cancer. Increasing resistance of cancer cells towards chemotherapeutic drugs along with detrimental side effects remained a concern. Thus, the urgency in developing new anticancer agents has been raised. Anticancer peptides have been proven to display potent activity against a wide variety of cancer cells. Several mode of actions describing their cytostatic and cytotoxic effect on cancer cells have been proposed which involves cell surface binding leading to membranolysis or internalization to reach their intracellular target. Understanding the mechanism of action of these anticancer peptides is important in achieving full therapeutic success. In the present article, we discuss the anticancer action of peptides accompanied by the mechanisms underpinning their toxicity to cancer cells.
Collapse
Affiliation(s)
- Tsuey Ning Soon
- School of Biosciences, Faculty of Medical and Health Sciences, Taylor's University, 47500 Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Adeline Yoke Yin Chia
- School of Biosciences, Faculty of Medical and Health Sciences, Taylor's University, 47500 Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Wei Hsum Yap
- School of Biosciences, Faculty of Medical and Health Sciences, Taylor's University, 47500 Subang Jaya, Selangor Darul Ehsan, Malaysia
| | - Yin-Quan Tang
- School of Biosciences, Faculty of Medical and Health Sciences, Taylor's University, 47500 Subang Jaya, Selangor Darul Ehsan, Malaysia
| |
Collapse
|
17
|
Yu TT, Kuppusamy R, Yasir M, Hassan MM, Alghalayini A, Gadde S, Deplazes E, Cranfield C, Willcox MD, Black DS, Kumar N. Design, Synthesis and Biological Evaluation of Biphenylglyoxamide-Based Small Molecular Antimicrobial Peptide Mimics as Antibacterial Agents. Int J Mol Sci 2020; 21:E6789. [PMID: 32947921 PMCID: PMC7555970 DOI: 10.3390/ijms21186789] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Revised: 09/14/2020] [Accepted: 09/14/2020] [Indexed: 01/14/2023] Open
Abstract
There has been an increasing interest in the development of antimicrobial peptides (AMPs) and their synthetic mimics as a novel class of antibiotics to overcome the rapid emergence of antibiotic resistance. Recently, phenylglyoxamide-based small molecular AMP mimics have been identified as potential leads to treat bacterial infections. In this study, a new series of biphenylglyoxamide-based small molecular AMP mimics were synthesised from the ring-opening reaction of N-sulfonylisatin bearing a biphenyl backbone with a diamine, followed by the conversion into tertiary ammonium chloride, quaternary ammonium iodide and guanidinium hydrochloride salts. Structure-activity relationship studies of the analogues identified the octanesulfonyl group as being essential for both Gram-positive and Gram-negative antibacterial activity, while the biphenyl backbone was important for Gram-negative antibacterial activity. The most potent analogue was identified to be chloro-substituted quaternary ammonium iodide salt 15c, which possesses antibacterial activity against both Gram-positive (MIC against Staphylococcus aureus = 8 μM) and Gram-negative bacteria (MIC against Escherichia coli = 16 μM, Pseudomonas aeruginosa = 63 μM) and disrupted 35% of pre-established S. aureus biofilms at 32 μM. Cytoplasmic membrane permeability and tethered bilayer lipid membranes (tBLMs) studies suggested that 15c acts as a bacterial membrane disruptor. In addition, in vitro toxicity studies showed that the potent compounds are non-toxic against human cells at therapeutic dosages.
Collapse
Affiliation(s)
- Tsz Tin Yu
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia; (T.T.Y.); (R.K.); (M.M.H.); (S.G.)
| | - Rajesh Kuppusamy
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia; (T.T.Y.); (R.K.); (M.M.H.); (S.G.)
| | - Muhammad Yasir
- School of Optometry and Vision Science, University of New South Wales, Sydney, NSW 2052, Australia; (M.Y.); (M.D.P.W.)
| | - Md. Musfizur Hassan
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia; (T.T.Y.); (R.K.); (M.M.H.); (S.G.)
| | - Amani Alghalayini
- School of Life Sciences, University of Technology Sydney, PO Box 123, Ultimo 2007, Australia; (A.A.); (E.D.); (C.C.)
| | - Satyanarayana Gadde
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia; (T.T.Y.); (R.K.); (M.M.H.); (S.G.)
| | - Evelyne Deplazes
- School of Life Sciences, University of Technology Sydney, PO Box 123, Ultimo 2007, Australia; (A.A.); (E.D.); (C.C.)
| | - Charles Cranfield
- School of Life Sciences, University of Technology Sydney, PO Box 123, Ultimo 2007, Australia; (A.A.); (E.D.); (C.C.)
| | - Mark D.P. Willcox
- School of Optometry and Vision Science, University of New South Wales, Sydney, NSW 2052, Australia; (M.Y.); (M.D.P.W.)
| | - David StC Black
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia; (T.T.Y.); (R.K.); (M.M.H.); (S.G.)
| | - Naresh Kumar
- School of Chemistry, The University of New South Wales, Sydney, NSW 2052, Australia; (T.T.Y.); (R.K.); (M.M.H.); (S.G.)
| |
Collapse
|
18
|
Garcia A, Deplazes E, Aili S, Padula MP, Touchard A, Murphy C, Mirissa Lankage U, Nicholson GM, Cornell B, Cranfield CG. Label-Free, Real-Time Phospholipase-A Isoform Assay. ACS Biomater Sci Eng 2020; 6:4714-4721. [PMID: 33455186 DOI: 10.1021/acsbiomaterials.0c00632] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
Phospholipase-A (PLA) enzymes catalyze the hydrolysis of ester bonds in select glycerophospholipids. Sensors for rapidly measuring the PLA activity in biological samples have relevance in the study of venom compositions and in medical diagnostics for the diagnosis of diseases such as acute pancreatitis. Current PLA sensor technologies are often restricted by the time it takes to prepare an assay, the necessity of using fluorescent labels, or the fact they might require strict pH control of the buffer vehicles used. Here we present a tethered bilayer lipid membrane (tBLM) impedance sensor array for the rapid and real-time detection of PLA, which includes the ability to selectively detect phospholipase-A2 (PLA2) from phospholipase-A1 (PLA1) isoforms. Comparing the activity of PLA1 and PLA2 in an array of tBLMs composed of ether phospholipids, ester phospholipids or ether-ester phospholipids allows for the rapid and reliable distinction between the isoforms, as measured using swept-frequency electrical impedance spectroscopy. After testing the assay using pure enzymes, we demonstrate the capacity of the sensor to identify specific PLA2-type, calcium-dependent activity from the venom of the South American bullet ant, Paraponera clavata, at a concentration of 1 μg/mL. The specificity of the phospholipase activity was corroborated using matrix-assisted laser-desorption/ionization time-of-flight mass spectrometry. As further validation, we tested the activities of a PLA1 isoform in the presence of different buffers commonly used in biology and biochemistry experiments. Sensitivity testing shows that PLA1 can be detected at an activity as low as 0.06 U/mL. The rapid and reliable detection of phospholipases presented in this study has potential applications in the study of animal venoms as well as in lipase bioreactors and point-of-care devices.
Collapse
Affiliation(s)
- Alvaro Garcia
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Evelyne Deplazes
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Samira Aili
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Matthew P Padula
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Axel Touchard
- CNRS, UMR Ecologie des Forêts de Guyane, AgroParisTech, CIRAD, INRA, Université de Guyane, Université des Antilles, Campus Agronomique, BP316, Kourou Cedex 97379, France
| | - Christopher Murphy
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Upeksha Mirissa Lankage
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Graham M Nicholson
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| | - Bruce Cornell
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia.,SDx Surgical Diagnostics Pty Ltd., U6 30-32 Barcoo Street, Roseville, New South Wales 2069, Australia
| | - Charles G Cranfield
- School of Life Sciences, University of Technology Sydney, Ultimo, New South Wales 2007, Australia
| |
Collapse
|
19
|
Ariawan AD, Sun B, Wojciechowski JP, Lin I, Du EY, Goodchild SC, Cranfield CG, Ittner LM, Thordarson P, Martin AD. Effect of polar amino acid incorporation on Fmoc-diphenylalanine-based tetrapeptides. SOFT MATTER 2020; 16:4800-4805. [PMID: 32400837 DOI: 10.1039/d0sm00320d] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Peptide hydrogels show great promise as extracellular matrix mimics due to their tuneable, fibrous nature. Through incorporation of polar cationic, polar anionic or polar neutral amino acids into the Fmoc-diphenylalanine motif, we show that electrostatic charge plays a key role in the properties of the subsequent gelators. Specifically, we show that an inverse relationship exists for biocompatibility in the solution state versus the gel state for cationic and anionic peptides. Finally, we use tethered bilayer lipid membrane (tBLM) experiments to suggest a likely mode of cytotoxicity for tetrapeptides which exhibit cytotoxicity in the solution state.
Collapse
Affiliation(s)
- A Daryl Ariawan
- Dementia Research Centre, Department of Biomedical Science, Faculty of Medicine and Health Sciences, Macquarie University, Sydney, NSW 2109, Australia.
| | | | | | | | | | | | | | | | | | | |
Collapse
|
20
|
Martin AD, Wojciechowski JP, Du EY, Rawal A, Stefen H, Au CG, Hou L, Cranfield CG, Fath T, Ittner LM, Thordarson P. Decoupling the effects of hydrophilic and hydrophobic moieties at the neuron-nanofibre interface. Chem Sci 2019; 11:1375-1382. [PMID: 34123262 PMCID: PMC8148083 DOI: 10.1039/c9sc05686f] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Peptide-based nanofibres are a versatile class of tunable materials with applications in optoelectronics, sensing and tissue engineering. However, the understanding of the nanofibre surface at the molecular level is limited. Here, a series of homologous dilysine–diphenylalnine tetrapeptides were synthesised and shown to self-assemble into water-soluble nanofibres. Despite the peptide nanofibres displaying similar morphologies, as evaluated through atomic force microscopy and neutron scattering, significant differences were observed in their ability to support sensitive primary neurons. Contact angle and labelling experiments revealed that differential presentation of lysine moieties at the fibre surface did not affect neuronal viability; however the mobility of phenylalanine residues at the nanofibre surface, elucidated through solid- and gel-state NMR studies and confirmed through tethered bilayer lipid membrane experiments, was found to be the determining factor in governing the suitability of a given peptide as a scaffold for primary neurons. This work offers new insights into characterising and controlling the nanofibre surface at the molecular level. The mobility of hydrophobic moieties at a peptide nanofibre surface determines its suitability as a scaffold for sensitive primary cells.![]()
Collapse
Affiliation(s)
- Adam D Martin
- Dementia Research Centre, Department of Biomedical Science, Faculty of Medicine and Health Sciences, Macquarie University Sydney NSW 2109 Australia
| | | | - Eric Y Du
- School of Chemistry, The Australian Centre for Nanomedicine, The ARC Centre of Excellence in Convergent Bio-Nano Science & Technology, University of New South Wales Sydney NSW 2052 Australia
| | - Aditya Rawal
- NMR Facility, Mark Wainwright Analytical Centre, The University of New South Wales Sydney 2052 New South Wales Australia
| | - Holly Stefen
- Dementia Research Centre, Department of Biomedical Science, Faculty of Medicine and Health Sciences, Macquarie University Sydney NSW 2109 Australia
| | - Carol G Au
- Dementia Research Centre, Department of Biomedical Science, Faculty of Medicine and Health Sciences, Macquarie University Sydney NSW 2109 Australia
| | - Liming Hou
- Dementia Research Centre, Department of Biomedical Science, Faculty of Medicine and Health Sciences, Macquarie University Sydney NSW 2109 Australia
| | - Charles G Cranfield
- School of Life Sciences, University of Technology Sydney Ultimo NSW 2007 Australia
| | - Thomas Fath
- Dementia Research Centre, Department of Biomedical Science, Faculty of Medicine and Health Sciences, Macquarie University Sydney NSW 2109 Australia
| | - Lars M Ittner
- Dementia Research Centre, Department of Biomedical Science, Faculty of Medicine and Health Sciences, Macquarie University Sydney NSW 2109 Australia
| | - Pall Thordarson
- School of Chemistry, The Australian Centre for Nanomedicine, The ARC Centre of Excellence in Convergent Bio-Nano Science & Technology, University of New South Wales Sydney NSW 2052 Australia
| |
Collapse
|
21
|
Abstract
This Review explores the class of plant-derived macrocyclic peptides called cyclotides. We include an account of their discovery, characterization, and distribution in the plant kingdom as well as a detailed analysis of their sequences and structures, biosynthesis and chemical synthesis, biological functions, and applications. These macrocyclic peptides are around 30 amino acids in size and are characterized by their head-to-tail cyclic backbone and cystine knot motif, which render them to be exceptionally stable, with resistance to thermal or enzymatic degradation. Routes to their chemical synthesis have been developed over the past two decades, and this capability has facilitated a wide range of mutagenesis and structure-activity relationship studies. In turn, these studies have both led to an increased understanding of their mechanisms of action as well as facilitated a range of applications in agriculture and medicine, as ecofriendly crop protection agents, and as drug leads or scaffolds for pharmaceutical design. Our overall objective in this Review is to provide readers with a comprehensive overview of cyclotides that we hope will stimulate further work on this fascinating family of peptides.
Collapse
Affiliation(s)
- Simon J de Veer
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
| | - Meng-Wei Kan
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
| | - David J Craik
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
| |
Collapse
|
22
|
Henriques ST, Peacock H, Benfield AH, Wang CK, Craik DJ. Is the Mirror Image a True Reflection? Intrinsic Membrane Chirality Modulates Peptide Binding. J Am Chem Soc 2019; 141:20460-20469. [PMID: 31765148 DOI: 10.1021/jacs.9b11194] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
Peptides with pharmaceutical activities are attractive drug leads, and knowledge of their mode-of-action is essential for translation into the clinic. Comparison of native and enantiomeric peptides has long been used as a powerful approach to discriminate membrane- or receptor-mediated modes-of-action on the basis of the assumption that interactions with cell membranes are independent of peptide chirality. Here, we revisit this paradigm with the cyclotide kalata B1, a drug scaffold with intrinsic membrane-binding activity whose enantiomer is less potent than native peptide. To investigate this chirality dependence, we compared peptide-lipid binding using mirror image model membranes. We synthesized phospholipids with non-natural chirality and demonstrate that native kalata B1 binds with higher affinity to phospholipids with chirality found in eukaryotic membranes. This study shows for the first time that the chiral environment of lipid bilayers can modulate the function of membrane-active peptides and challenges the view that peptide-lipid interactions are achiral.
Collapse
Affiliation(s)
- Sónia Troeira Henriques
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia.,School of Biomedical Sciences, Faculty of Health, Institute of Health & Biomedical Innovation , Queensland University of Technology , Translational Research Institute , Brisbane , Queensland 4102 , Australia
| | - Hayden Peacock
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
| | - Aurélie H Benfield
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia.,School of Biomedical Sciences, Faculty of Health, Institute of Health & Biomedical Innovation , Queensland University of Technology , Translational Research Institute , Brisbane , Queensland 4102 , Australia
| | - Conan K Wang
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
| | - David J Craik
- Institute for Molecular Bioscience , The University of Queensland , Brisbane , Queensland 4072 , Australia
| |
Collapse
|
23
|
Camarero JA, Campbell MJ. The Potential of the Cyclotide Scaffold for Drug Development. Biomedicines 2019; 7:biomedicines7020031. [PMID: 31010257 PMCID: PMC6631875 DOI: 10.3390/biomedicines7020031] [Citation(s) in RCA: 33] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2019] [Revised: 04/13/2019] [Accepted: 04/15/2019] [Indexed: 12/11/2022] Open
Abstract
Cyclotides are a novel class of micro-proteins (≈30-40 residues long) with a unique topology containing a head-to-tail cyclized backbone structure further stabilized by three disulfide bonds that form a cystine knot. This unique molecular framework makes them exceptionally stable to physical, chemical, and biological degradation compared to linear peptides of similar size. The cyclotides are also highly tolerant to sequence variability, aside from the conserved residues forming the cystine knot, and are orally bioavailable and able to cross cellular membranes to modulate intracellular protein-protein interactions (PPIs), both in vitro and in vivo. These unique properties make them ideal scaffolds for many biotechnological applications, including drug discovery. This review provides an overview of the properties of cyclotides and their potential for the development of novel peptide-based therapeutics. The selective disruption of PPIs still remains a very challenging task, as the interacting surfaces are relatively large and flat. The use of the cell-permeable highly constrained polypeptide molecular frameworks, such as the cyclotide scaffold, has shown great promise, as it provides unique pharmacological properties. The use of molecular techniques, such as epitope grafting, and molecular evolution have shown to be highly effective for the selection of bioactive cyclotides. However, despite successes in employing cyclotides to target PPIs, some of the challenges to move them into the clinic still remain.
Collapse
Affiliation(s)
- Julio A Camarero
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 9033, USA.
- Norris Comprehensive Cancer Center, University of Southern California, Los Angeles, Los Angeles, CA 9033, USA.
| | - Maria Jose Campbell
- Department of Pharmacology and Pharmaceutical Sciences, University of Southern California, Los Angeles, CA 9033, USA.
| |
Collapse
|
24
|
Alghalayini A, Garcia A, Berry T, Cranfield CG. The Use of Tethered Bilayer Lipid Membranes to Identify the Mechanisms of Antimicrobial Peptide Interactions with Lipid Bilayers. Antibiotics (Basel) 2019; 8:antibiotics8010012. [PMID: 30704119 PMCID: PMC6466558 DOI: 10.3390/antibiotics8010012] [Citation(s) in RCA: 41] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/08/2019] [Revised: 01/28/2019] [Accepted: 01/29/2019] [Indexed: 01/29/2023] Open
Abstract
This review identifies the ways in which tethered bilayer lipid membranes (tBLMs) can be used for the identification of the actions of antimicrobials against lipid bilayers. Much of the new research in this area has originated, or included researchers from, the southern hemisphere, Australia and New Zealand in particular. More and more, tBLMs are replacing liposome release assays, black lipid membranes and patch-clamp electrophysiological techniques because they use fewer reagents, are able to obtain results far more quickly and can provide a uniformity of responses with fewer artefacts. In this work, we describe how tBLM technology can and has been used to identify the actions of numerous antimicrobial agents.
Collapse
Affiliation(s)
- Amani Alghalayini
- School of Life Science, University of Technology Sydney, Ultimo, NSW 2007, Australia.
| | - Alvaro Garcia
- School of Life Science, University of Technology Sydney, Ultimo, NSW 2007, Australia.
| | - Thomas Berry
- School of Life Science, University of Technology Sydney, Ultimo, NSW 2007, Australia.
| | - Charles G Cranfield
- School of Life Science, University of Technology Sydney, Ultimo, NSW 2007, Australia.
| |
Collapse
|
25
|
Facey JA, Steele JR, Violi JP, Mitrovic SM, Cranfield C. An examination of microcystin-LR accumulation and toxicity using tethered bilayer lipid membranes (tBLMs). Toxicon 2018; 158:51-56. [PMID: 30521837 DOI: 10.1016/j.toxicon.2018.11.432] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2018] [Revised: 11/21/2018] [Accepted: 11/22/2018] [Indexed: 01/23/2023]
Abstract
Microcystin-LR (MC-LR) is a potent cyanobacterial toxin responsible for animal and human poisonings worldwide. MC-LR is found in organisms throughout the foodweb, however there is conjecture regarding whether it biomagnifies. Few studies have investigated how MC-LR interacts with lipid membranes, a determinant of biomagnification potential. We tested whether 1 μM MC-LR irreversibly associates with lipid bilayers or causes the creation of pore defects upon short and long-term exposure. Using tethered bilayer lipid membranes (tBLMs), we observed an increase in membrane conduction in tBLMs, representing an interaction of microcystin-LR with the lipid bilayer and a change in membrane packing properties. However, there were minimal changes in membrane capacitance upon short and long-term exposure, and MC-LR exhibited a rapid off-rate. Upon 24 h exposure to the toxin, no lipophilic multimeric complexes were detected capable of altering the toxin's off-rate. There was no evidence of the creation of new pores. This study demonstrates that MC-LR does not irreversibly imbed itself into lipids membranes after short or long-term exposure and suggests MC-LR does not biomagnify through the food web via lipid storage.
Collapse
Affiliation(s)
- Jordan A Facey
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW, 2000, Australia.
| | - Joel R Steele
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW, 2000, Australia
| | - Jake P Violi
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW, 2000, Australia
| | - Simon M Mitrovic
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW, 2000, Australia
| | - Charles Cranfield
- School of Life Sciences, University of Technology Sydney, PO Box 123, Broadway, NSW, 2000, Australia
| |
Collapse
|
26
|
Berry T, Dutta D, Chen R, Leong A, Wang H, Donald WA, Parviz M, Cornell B, Willcox M, Kumar N, Cranfield CG. Lipid Membrane Interactions of the Cationic Antimicrobial Peptide Chimeras Melimine and Cys-Melimine. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2018; 34:11586-11592. [PMID: 30119612 DOI: 10.1021/acs.langmuir.8b01701] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Melimine and its derivatives are synthetic chimeric antimicrobial agents based on protamine and melittin. The binding of solubilized melimine and its derivative, with a cysteine on N-terminus, (cys-melimine) on tethered bilayer lipid membranes (tBLMs) was examined using ac electrical impedance spectroscopy. The addition of melimine and cys-melimine initially increased membrane conduction, which subsequently falls over time. The results were obtained for tBLMs comprising zwitterionic phosphatidylcholine, anionic phosphatidylglycerol, or tBLMs made using purified lipids from Escherichia coli. The effect on conduction is more marked with the cysteine variant than the noncysteine variant. The variation in membrane conduction most probably arises from individual melimines inducing increased ionic permeability, which is then reduced as the melimines aggregate and phase-separate within the membrane. The actions of these antimicrobials are modeled in terms of altering the critical packing parameter (CPP) of the membranes. The variations in the peptide length of cys-melimine were compared with a truncated version of the peptide, cys-mel4. The results suggest that the smaller molecule impacts the membrane by a mechanism that increases the average CPP, reducing membrane conduction. Alternatively, an uncharged alanine-replacement version of melimine still produced an increase in membrane conduction, further supporting the CPP model of geometry-induced toroidal pore alterations. All the data were then compared to their antimicrobial effectiveness for the Gram-positive and Gram-negative strains of bacteria, and their fusogenic properties were examined using dynamic light scattering in 1-oleoyl-2-hydroxy- sn-glycero-3-phosphocholine lipid spheroids. We conclude that a degree of correlation exists between the antimicrobial effectiveness of the peptides studied here and their modulation of membrane conductivity.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | - Bruce Cornell
- SDx Tethered Membranes Pty Ltd , Unit 6, 30-32 Barcoo Street , Roseville , New South Wales 2069 , Australia
| | | | | | | |
Collapse
|
27
|
The effect of H 3O + on the membrane morphology and hydrogen bonding of a phospholipid bilayer. Biophys Rev 2018; 10:1371-1376. [PMID: 30219992 DOI: 10.1007/s12551-018-0454-z] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2018] [Accepted: 09/06/2018] [Indexed: 12/30/2022] Open
Abstract
At the 2017 meeting of the Australian Society for Biophysics, we presented the combined results from two recent studies showing how hydronium ions (H3O+) modulate the structure and ion permeability of phospholipid bilayers. In the first study, the impact of H3O+ on lipid packing had been identified using tethered bilayer lipid membranes in conjunction with electrical impedance spectroscopy and neutron reflectometry. The increased presence of H3O+ (i.e. lower pH) led to a significant reduction in membrane conductivity and increased membrane thickness. A first-order explanation for the effect was assigned to alterations in the steric packing of the membrane lipids. Changes in packing were described by a critical packing parameter (CPP) related to the interfacial area and volume and shape of the membrane lipids. We proposed that increasing the concentraton of H3O+ resulted in stronger hydrogen bonding between the phosphate oxygens at the water-lipid interface leading to a reduced area per lipid and slightly increased membrane thickness. At the meeting, a molecular model for these pH effects based on the result of our second study was presented. Multiple μs-long, unrestrained molecular dynamic (MD) simulations of a phosphatidylcholine lipid bilayer were carried out and showed a concentration dependent reduction in the area per lipid and an increase in bilayer thickness, in agreement with experimental data. Further, H3O+ preferentially accumulated at the water-lipid interface, suggesting the localised pH at the membrane surface is much lower than the bulk bathing solution. Another significant finding was that the hydrogen bonds formed by H3O+ ions with lipid headgroup oxygens are, on average, shorter in length and longer-lived than the ones formed in bulk water. In addition, the H3O+ ions resided for longer periods in association with the carbonyl oxygens than with either phosphate oxygen in lipids. In summary, the MD simulations support a model where the hydrogen bonding capacity of H3O+ for carbonyl and phosphate oxygens is the origin of the pH-induced changes in lipid packing in phospholipid membranes. These molecular-level studies are an important step towards a better understanding of the effect of pH on biological membranes.
Collapse
|
28
|
Membrane affinity and fluorescent labelling: comparative study of monolayer interaction, cellular uptake and cytotoxicity profile of carboxyfluorescein-conjugated cationic peptides. Amino Acids 2018; 50:1557-1571. [PMID: 30099595 DOI: 10.1007/s00726-018-2630-7] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2018] [Accepted: 07/30/2018] [Indexed: 02/07/2023]
Abstract
Fluorescent labelling is a common approach to reveal the molecular details of cellular uptake, internalisation, transport, distribution processes in biological systems. The conjugation with a fluorescent moiety might affect relevant physico-chemical and in vitro transport properties of the bioactive component. A representative set of seven cationic peptides-including cell-penetrating peptides as well as antimicrobial peptides and synthetic derivatives-was selected for our comparative study. Membrane affinity of the peptides and their 5(6)-carboxyfluorescein (Cf) derivatives was determined quantitatively and compared applying Langmuir monolayer of zwitterionic (DPPC) and negatively charged (DPPC + DPPG) lipids as cell membrane models. The interaction with neutral lipid layer is mainly governed by the overall hydrophobicity of the molecule which is remarkably increased by Cf-conjugation for the most hydrophobic Magainin, Melittin and Transportan. A significantly enhanced membrane affinity was detected in negatively charged lipid model monolayer for all of the peptides since the combination of electrostatic and hydrophobic interaction is active in that case. The Cf-conjugation improved the penetration ability of Penetratin and Dhvar4 suggesting that both the highly charged character (Z/n) and the increased hydrophobicity by Cf-conjugation present important contribution to membrane interaction. This effect might also responsible for the observed high in vitro internalisation rate of Penetratin and Dhvar4, while according to in vitro studies they did not cause damage of cell membrane. From the experiments with the given seven cationic peptides, it can be concluded that the Cf-conjugation alters the degree of membrane interaction of such peptides which are moderately hydrophobic and highly charged.
Collapse
|
29
|
Lima de Oliveira A, Maffud Cilli E, Ros U, Crusca E, Lanio ME, Alvarez C, Schreier S, Aguiar Pertinhez T, Spisni A. Insights on the structure-activity relationship of peptides derived from Sticholysin II. Biopolymers 2018; 110. [PMID: 29359791 DOI: 10.1002/bip.23097] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2017] [Revised: 11/26/2017] [Accepted: 12/03/2017] [Indexed: 02/06/2023]
Abstract
Sticholysin II (StII) is a pore-forming actinoporin from the sea anemone Stichodactyla helianthus. A mechanistic model of its action has been proposed: proteins bind to cell membrane, insert their N-termini into the lipid core and assemble into homo-tetramer pores responsible for host-cell death. Because very likely the first 10 residues of StII N-terminus are critical for membrane penetration, to dissect the molecular details of that functionality, we studied two synthetic peptides: StII1-30 and StII16-35 . They show diverse haemolytic and candidacidal activity that correlate with distinct orientations in SDS micelles. NMR shows that StII1-30 partly inserts into the micelle, while StII16-35 lays on the micelle surface. These results justify the diverse concentration dependence of their candidacidal activity supposing a different mechanism of action and providing new hints on StII lytic activity at molecular level. Biotechnological application of these peptides, focused on the development of therapeutic immunocomplexes, may be envisaged.
Collapse
Affiliation(s)
- Aline Lima de Oliveira
- Institute of Chemistry, University of Brasilia, Brasilia, DF, Brazil
- Department of Biochemistry and Chemical Technology, Institute of Chemistry, São Paulo State University, Araraquara, Brazil
| | | | - Uris Ros
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Edson Crusca
- Center for Protein Studies, Biology Faculty, University of Havana, Havana, Cuba
| | - María Eliana Lanio
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
| | - Carlos Alvarez
- Department of Biochemistry, Institute of Chemistry, University of São Paulo, São Paulo, Brazil
- Department of Medicine and Surgery, Unit of Biochemistry, University of Parma, Parma, Italy
| | - Shirley Schreier
- Department of Medicine and Surgery, Unit of Biochemistry, University of Parma, Parma, Italy
| | - Thelma Aguiar Pertinhez
- Department of Biochemistry and Chemical Technology, Institute of Chemistry, São Paulo State University, Araraquara, Brazil
- Transfusion Medicine Unit, AUSL - IRCCS Reggio Emilia, Italy
| | - Alberto Spisni
- Department of Biochemistry and Chemical Technology, Institute of Chemistry, São Paulo State University, Araraquara, Brazil
| |
Collapse
|
30
|
Deplazes E, Poger D, Cornell B, Cranfield CG. The effect of hydronium ions on the structure of phospholipid membranes. Phys Chem Chem Phys 2018; 20:357-366. [DOI: 10.1039/c7cp06776c] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
This work studies the mechanisms by which hydronium ions modulate the structure of phospholipid bilayers.
Collapse
Affiliation(s)
- Evelyne Deplazes
- School of Biomedical Sciences
- Curtin Health Innovation Research Institute and Curtin Institute for Computation
- Curtin University
- Perth
- Australia
| | - David Poger
- School of Chemistry and Molecular Biosciences
- The University of Queensland
- Brisbane
- Australia
| | | | | |
Collapse
|