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Szomek M, Akkerman V, Lauritsen L, Walther HL, Juhl AD, Thaysen K, Egebjerg JM, Covey DF, Lehmann M, Wessig P, Foster AJ, Poolman B, Werner S, Schneider G, Müller P, Wüstner D. Ergosterol promotes aggregation of natamycin in the yeast plasma membrane. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184350. [PMID: 38806103 DOI: 10.1016/j.bbamem.2024.184350] [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: 01/12/2024] [Revised: 05/11/2024] [Accepted: 05/24/2024] [Indexed: 05/30/2024]
Abstract
Polyene macrolides are antifungal substances, which interact with cells in a sterol-dependent manner. While being widely used, their mode of action is poorly understood. Here, we employ ultraviolet-sensitive (UV) microscopy to show that the antifungal polyene natamycin binds to the yeast plasma membrane (PM) and causes permeation of propidium iodide into cells. Right before membrane permeability became compromised, we observed clustering of natamycin in the PM that was independent of PM protein domains. Aggregation of natamycin was paralleled by cell deformation and membrane blebbing as revealed by soft X-ray microscopy. Substituting ergosterol for cholesterol decreased natamycin binding and caused a reduced clustering of natamycin in the PM. Blocking of ergosterol synthesis necessitates sterol import via the ABC transporters Aus1/Pdr11 to ensure natamycin binding. Quantitative imaging of dehydroergosterol (DHE) and cholestatrienol (CTL), two analogues of ergosterol and cholesterol, respectively, revealed a largely homogeneous lateral sterol distribution in the PM, ruling out that natamycin binds to pre-assembled sterol domains. Depletion of sphingolipids using myriocin increased natamycin binding to yeast cells, likely by increasing the ergosterol fraction in the outer PM leaflet. Importantly, binding and membrane aggregation of natamycin was paralleled by a decrease of the dipole potential in the PM, and this effect was enhanced in the presence of myriocin. We conclude that ergosterol promotes binding and aggregation of natamycin in the yeast PM, which can be synergistically enhanced by inhibitors of sphingolipid synthesis.
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Affiliation(s)
- Maria Szomek
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Vibeke Akkerman
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Line Lauritsen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Hanna-Loisa Walther
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Alice Dupont Juhl
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Katja Thaysen
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Jacob Marcus Egebjerg
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark
| | - Douglas F Covey
- Department of Developmental Biology, Washington University in St. Louis, St. Louis, MO 63110, USA; Taylor Family Institute for Innovative Psychiatric Research, USA
| | - Max Lehmann
- Institute for Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam, Germany
| | - Pablo Wessig
- Institute for Chemistry, University of Potsdam, Karl-Liebknecht-Str. 24-25, D-14476 Potsdam, Germany
| | - Alexander J Foster
- Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 Groningen, the Netherlands
| | - Bert Poolman
- Department of Biochemistry, University of Groningen, Nijenborgh 4, 9747 Groningen, the Netherlands
| | - Stephan Werner
- Department of X-Ray Microscopy, Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Gerd Schneider
- Department of X-Ray Microscopy, Helmholtz-Zentrum Berlin, Albert-Einstein-Str. 15, 12489 Berlin, Germany
| | - Peter Müller
- Department of Biology, Humboldt University Berlin, Invalidenstr. 43, D-10115 Berlin, Germany
| | - Daniel Wüstner
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, DK-5230 Odense M, Denmark.
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2
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Garza-Miyazato D, Hanashima S, Umegawa Y, Murata M, Kinoshita M, Matsumori N, Greimel P. Mode of molecular interaction of triterpenoid saponin ginsenoside Rh2 with membrane lipids in liquid-disordered phases. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2024; 1866:184366. [PMID: 38960300 DOI: 10.1016/j.bbamem.2024.184366] [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: 02/03/2024] [Revised: 06/07/2024] [Accepted: 06/24/2024] [Indexed: 07/05/2024]
Abstract
Ginsenoside Rh2 (Rh2) is a ginseng saponin comprising a triterpene core and one unit of glucose and has attracted much attention due to its diverse biological activities. In the present study, we used small-angle X-ray diffraction, solid-state NMR, fluorescence microscopy, and MD simulations to investigate the molecular interaction of Rh2 with membrane lipids in the liquid-disordered (Ld) phase mainly composed of palmitoyloleoylphosphatidylcholine compared with those in liquid-ordered (Lo) phase mainly composed of sphingomyelin and cholesterol. The electron density profiles determined by X-ray diffraction patterns indicated that Rh2 tends to be present in the shallow interior of the bilayer in the Ld phase, while Rh2 accumulation was significantly smaller in the Lo phase. Order parameters at intermediate depths in the bilayer leaflet obtained from 2H NMR spectra and MD simulations indicated that Rh2 reduces the order of the acyl chains of lipids in the Ld phase. The dihydroxy group and glucose moiety at both ends of the hydrophobic triterpene core of Rh2 cause tilting of the molecular axis relative to the membrane normal, which may enhance membrane permeability by loosening the packing of lipid acyl chains. These features of Rh2 are distinct from steroidal saponins such as digitonin and dioscin, which exert strong membrane-disrupting activity.
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Affiliation(s)
- Darcy Garza-Miyazato
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Shinya Hanashima
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyama-cho Minami, Tottori 680-8552, Japan.
| | - Yuichi Umegawa
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Michio Murata
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Forefront Research Centre for Fundamental Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
| | - Masanao Kinoshita
- Department of Chemistry, Graduate School of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Nobuaki Matsumori
- Department of Chemistry, Graduate School of Science, Kyushu University, 744 Motooka, Nishi-ku, Fukuoka 819-0395, Japan
| | - Peter Greimel
- Laboratory for Cell Function Dynamics, RIKEN Center for Brain Science, Wako, Saitama 351-0198, Japan
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Place AR, Ramos-Franco J, Waters AL, Peng J, Hamann MT. Sterolysin from a 1950s culture of Karlodinium veneficum (aka Gymnodinium veneficum Ballantine) forms lethal sterol dependent membrane pores. Sci Rep 2024; 14:17998. [PMID: 39097621 PMCID: PMC11297910 DOI: 10.1038/s41598-024-68669-0] [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: 02/19/2024] [Accepted: 07/26/2024] [Indexed: 08/05/2024] Open
Abstract
In 1957 Abbott and Ballantine described a highly toxic activity from a dinoflagellate isolated from the English Channel in 1949 by Mary Park. From a culture maintained at Plymouth Laboratory since 1950, we have been able to isolate two toxic molecules (abbotoxin and 59-E-Chloro-abbotoxin), determine the planar structures by analysis of HRMS and 1D and 2D NMR spectra, and found them to be karlotoxin (KmTx) congeners. Both toxins kill larval zebrafish with symptoms identical to those described by Abbot and Ballantine for gobies (Gobius virescens). Using surface plasma resonance the sterol binding specificity of karlotoxins is shown to require desmethyl sterols. Our results with black lipid membranes indicate that karlotoxin forms large-conductance channels in the lipid membrane, which are characterized by large ionic conductance, poor ionic selectivity, and a complex gating behavior that exhibits strong voltage dependence and multiple gating patterns. In addition, we show that KmTx 2 pore formation is a highly targeted mechanism involving sterol-specificity. This is the first report of the functional properties of the membrane pores formed by karlotoxins and is consistent with the initial observations of Abbott and Ballantine from 1957.
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Affiliation(s)
- Allen R Place
- Institute of Marine and Environmental Technology, University of Maryland Center for Environmental Sciences, Suite 236 Rita Rossi Colwell Center, Baltimore, MD, 21202, USA.
| | - Josefina Ramos-Franco
- Department of Physiology and Biophysics, Rush University Medical Center, Chicago, IL, 60612, USA
| | - Amanda L Waters
- Department of Chemistry, University of Central Oklahoma, Edmond, OK, 73034, USA
| | - Jiangnan Peng
- Department of Chemistry, Morgan State University, Baltimore, MD, 21251, USA
- COP Drug Discovery and Biomedical Sciences, Medical University of South Carolina, Charleston, SC, 29425-5700, USA
| | - Mark T Hamann
- Department of Chemistry, Morgan State University, Baltimore, MD, 21251, USA
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Tulloch LB, Tinti M, Wall RJ, Weidt SK, Corpas- Lopez V, Dey G, Smith TK, Fairlamb AH, Barrett MP, Wyllie S. Sterol 14-alpha demethylase (CYP51) activity in Leishmania donovani is likely dependent upon cytochrome P450 reductase 1. PLoS Pathog 2024; 20:e1012382. [PMID: 38991025 PMCID: PMC11265716 DOI: 10.1371/journal.ppat.1012382] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2024] [Revised: 07/23/2024] [Accepted: 06/30/2024] [Indexed: 07/13/2024] Open
Abstract
Liposomal amphotericin B is an important frontline drug for the treatment of visceral leishmaniasis, a neglected disease of poverty. The mechanism of action of amphotericin B (AmB) is thought to involve interaction with ergosterol and other ergostane sterols, resulting in disruption of the integrity and key functions of the plasma membrane. Emergence of clinically refractory isolates of Leishmania donovani and L. infantum is an ongoing issue and knowledge of potential resistance mechanisms can help to alleviate this problem. Here we report the characterisation of four independently selected L. donovani clones that are resistant to AmB. Whole genome sequencing revealed that in three of the moderately resistant clones, resistance was due solely to the deletion of a gene encoding C24-sterol methyltransferase (SMT1). The fourth, hyper-resistant resistant clone (>60-fold) was found to have a 24 bp deletion in both alleles of a gene encoding a putative cytochrome P450 reductase (P450R1). Metabolic profiling indicated these parasites were virtually devoid of ergosterol (0.2% versus 18% of total sterols in wild-type) and had a marked accumulation of 14-methylfecosterol (75% versus 0.1% of total sterols in wild-type) and other 14-alpha methylcholestanes. These are substrates for sterol 14-alpha demethylase (CYP51) suggesting that this enzyme may be a bona fide P450R specifically involved in electron transfer from NADPH to CYP51 during catalysis. Deletion of P450R1 in wild-type cells phenocopied the metabolic changes observed in our AmB hyper-resistant clone as well as in CYP51 nulls. Likewise, addition of a wild type P450R1 gene restored sterol profiles to wild type. Our studies indicate that P450R1 is essential for L. donovani amastigote viability, thus loss of this gene is unlikely to be a driver of clinical resistance. Nevertheless, investigating the mechanisms underpinning AmB resistance in these cells provided insights that refine our understanding of the L. donovani sterol biosynthetic pathway.
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Affiliation(s)
- Lindsay B. Tulloch
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Michele Tinti
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Richard J. Wall
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Stefan K. Weidt
- Glasgow Polyomics, College of Medical, Veterinary and Life Sciences, University of Glasgow, Garscube Estate, Bearsden, Glasgow, United Kingdom
| | - Victoriano Corpas- Lopez
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Gourav Dey
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Terry K. Smith
- Biomedical Sciences Research Complex, University of St Andrews, St Andrews, United Kingdom
| | - Alan H. Fairlamb
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
| | - Michael P. Barrett
- Glasgow Polyomics, College of Medical, Veterinary and Life Sciences, University of Glasgow, Garscube Estate, Bearsden, Glasgow, United Kingdom
- School of Infection & Immunity, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Susan Wyllie
- Wellcome Centre for Anti-Infectives Research, School of Life Sciences, University of Dundee, Dow Street, Dundee, United Kingdom
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Omelchuk O, Tevyashova A, Efimova S, Grammatikova N, Bychkova E, Zatonsky G, Dezhenkova L, Savin N, Solovieva S, Ostroumova O, Shchekotikhin A. A Study on the Effect of Quaternization of Polyene Antibiotics' Structures on Their Activity, Toxicity, and Impact on Membrane Models. Antibiotics (Basel) 2024; 13:608. [PMID: 39061290 PMCID: PMC11274224 DOI: 10.3390/antibiotics13070608] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2024] [Revised: 06/24/2024] [Accepted: 06/27/2024] [Indexed: 07/28/2024] Open
Abstract
Polyene antibiotics have been used in antifungal therapy since the mid-twentieth century. They are highly valued for their broad spectrum of activity and the rarity of pathogen resistance to their action. However, their use in the treatment of systemic mycoses often results in serious side-effects. Recently, there has been a renewed interest in the development of new antifungal drugs based on polyenes, particularly due to the emergence of highly dangerous pathogenic strains of fungi, such as Candida auris, and the increased incidence of mucormycosis. Considerable understanding has been established regarding the structure-biological activity relationships of polyene antifungals. Yet, no previous studies have examined the effect of introducing quaternized fragments into their molecular structure. In this study, we present a series of amides of amphotericin B, nystatin, and natamycin bearing a quaternized group in the side chain, and discuss their biological properties: antifungal activity, cytotoxicity, and effects on lipid bilayers that mimic fungal and mammalian cell membranes. Our research findings suggest that the nature of the introduced quaternized residue plays a more significant role than merely the introduction of a constant positive charge. Among the tested polyenes, derivatives 4b, 5b, and 6b, which contain a fragment of N-methyl-4-(aminomethyl)pyridinium in their structure, are particularly noteworthy due to their biological activity.
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Affiliation(s)
- Olga Omelchuk
- Gause Institute of New Antibiotics, 11 B. Pirogovskaya, Moscow 119021, Russia (G.Z.)
| | - Anna Tevyashova
- Gause Institute of New Antibiotics, 11 B. Pirogovskaya, Moscow 119021, Russia (G.Z.)
- School of Science, Constructor University, Campus Ring 1, 28759 Bremen, Germany
| | - Svetlana Efimova
- Institute of Cytology, The Russian Academy of Sciences, 4 Tikhoretsky Ave., St. Petersburg 194064, Russia; (S.E.); (O.O.)
| | - Natalia Grammatikova
- Gause Institute of New Antibiotics, 11 B. Pirogovskaya, Moscow 119021, Russia (G.Z.)
| | - Elena Bychkova
- Gause Institute of New Antibiotics, 11 B. Pirogovskaya, Moscow 119021, Russia (G.Z.)
| | - George Zatonsky
- Gause Institute of New Antibiotics, 11 B. Pirogovskaya, Moscow 119021, Russia (G.Z.)
| | - Lyubov Dezhenkova
- Gause Institute of New Antibiotics, 11 B. Pirogovskaya, Moscow 119021, Russia (G.Z.)
| | - Nikita Savin
- Research Laboratory of Biophysics, National University of Science and Technology “MISIS”, 4 p.1 Leninsky Pr., Moscow 119049, Russia
| | - Svetlana Solovieva
- Gause Institute of New Antibiotics, 11 B. Pirogovskaya, Moscow 119021, Russia (G.Z.)
| | - Olga Ostroumova
- Institute of Cytology, The Russian Academy of Sciences, 4 Tikhoretsky Ave., St. Petersburg 194064, Russia; (S.E.); (O.O.)
| | - Andrey Shchekotikhin
- Gause Institute of New Antibiotics, 11 B. Pirogovskaya, Moscow 119021, Russia (G.Z.)
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Malykhina AI, Efimova SS, Andriianov VS, Ostroumova OS. The interaction of plant flavones with amphotericin B: Consequences for its pore-forming ability. Biomed Pharmacother 2024; 175:116723. [PMID: 38723514 DOI: 10.1016/j.biopha.2024.116723] [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: 03/12/2024] [Revised: 04/25/2024] [Accepted: 05/06/2024] [Indexed: 06/03/2024] Open
Abstract
The growth of antibiotic resistance to antifungal drugs contributes to the search for new ways to enhance their effectiveness and reduce toxicity. The undeniable advantage of polyene macrolide antibiotic amphotericin B (AmB) which ensures low pathogen resistance is its mechanism of action related to the formation of transmembrane pores in target lipid membranes. Here, we investigated the effects of plant flavones, chrysin, wogonin, baicalein, apigenin, scutellarein, luteolin, morin and fisetin on the pore-forming activity of AmB in the sterol-enriched membranes by electrophysiological assays. Сhrysin, wogonin, baicalein, apigenin, scutellarein, and luteolin were shown to decrease the AmB pore-forming activity in the bilayers composed of palmitoyloleylphosphocholine independently of their sterol composition. Morin and fisetin led to the increase and decrease in the AmB pore-forming activity in the ergosterol- and cholesterol-containing bilayers respectively. Differential scanning microcalorimetry of the gel-to-liquid crystalline phase transition of membrane forming lipids, molecular dynamics simulations, and absorbance spectroscopy revealed the possibility of direct interactions between AmB and some flavones in the water and/or in the lipid bilayer. The influence of these interactions on the antibiotic partitioning between aqueous solution and membrane and/or its transition between different states in the bilayer was discussed.
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Affiliation(s)
- Anna I Malykhina
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology of Russian Academy of Sciences, Tikhoretsky 4, Saint Petersburg 194064, Russian Federation
| | - Svetlana S Efimova
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology of Russian Academy of Sciences, Tikhoretsky 4, Saint Petersburg 194064, Russian Federation
| | - Vladimir S Andriianov
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology of Russian Academy of Sciences, Tikhoretsky 4, Saint Petersburg 194064, Russian Federation
| | - Olga S Ostroumova
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology of Russian Academy of Sciences, Tikhoretsky 4, Saint Petersburg 194064, Russian Federation.
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Martínez I, Rivera-Santiago L, Rodríguez-Hernández KD, Galván-Hernández A, Rodríguez-Fragoso L, Díaz-Peralta L, Torres-Martínez L, Agredano-Moreno LT, Jiménez-García LF, Ortega-Blake I, Espinoza B. A Promising Amphotericin B Derivative Induces Morphological Alterations, Mitochondrial Damage, and Oxidative Stress In Vitro and Prevents Mice from Death Produced by a Virulent Strain of Trypanosoma cruzi. Microorganisms 2024; 12:1064. [PMID: 38930447 PMCID: PMC11205368 DOI: 10.3390/microorganisms12061064] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2024] [Revised: 05/02/2024] [Accepted: 05/17/2024] [Indexed: 06/28/2024] Open
Abstract
Chagas Disease is a neglected tropical disease caused by the protozoan parasite Trypanosoma cruzi, affecting 6-8 million people, mainly in Latin America. The medical treatment is based on two compounds, benznidazole and nifurtimox, with limited effectiveness and that produce severe side effects; consequently, there is an urgent need to develop new, safe, and effective drugs. Amphotericin B is the most potent antimycotic known to date. A21 is a derivative of this compound with the property of binding to ergosterol present in cell membranes of some organisms. In the search for a new therapeutic drug against T. cruzi, the objective of this work was to study the in vitro and in vivo effects of A21 derivative on T. cruzi. Our results show that the A21 increased the reactive oxygen species and reduced the mitochondrial membrane potential, affecting the morphology, metabolism, and cell membrane permeability of T. cruzi in vitro. Even more important was finding that in an in vivo murine model of infection, A21 in combination with benznidazole was able to reduce blood parasitemia, diminish the immune inflammatory infiltrate in skeletal muscle and rescue all the mice from death due to a virulent T. cruzi strain.
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Affiliation(s)
- Ignacio Martínez
- Laboratorio de Estudios Sobre Tripanosomiasis y Leishmaniasis, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City 04510, Mexico; (I.M.); (L.R.-S.); (K.D.R.-H.); (L.T.-M.)
| | - Lucio Rivera-Santiago
- Laboratorio de Estudios Sobre Tripanosomiasis y Leishmaniasis, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City 04510, Mexico; (I.M.); (L.R.-S.); (K.D.R.-H.); (L.T.-M.)
| | - Karla Daniela Rodríguez-Hernández
- Laboratorio de Estudios Sobre Tripanosomiasis y Leishmaniasis, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City 04510, Mexico; (I.M.); (L.R.-S.); (K.D.R.-H.); (L.T.-M.)
| | - Arturo Galván-Hernández
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, Cuernavaca 62251, Morelos, Mexico; (A.G.-H.); (L.D.-P.); (I.O.-B.)
| | - Lourdes Rodríguez-Fragoso
- Facultad de Farmacia, Universidad Autónoma del Estado de Morelos, Av. Universidad, 1001 Col. Chamilpa, Cuernavaca 62210, Morelos, Mexico;
| | - Lucero Díaz-Peralta
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, Cuernavaca 62251, Morelos, Mexico; (A.G.-H.); (L.D.-P.); (I.O.-B.)
| | - Lisset Torres-Martínez
- Laboratorio de Estudios Sobre Tripanosomiasis y Leishmaniasis, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City 04510, Mexico; (I.M.); (L.R.-S.); (K.D.R.-H.); (L.T.-M.)
| | | | - Luis Felipe Jiménez-García
- Facultad de Ciencias, Universidad Nacional Autónoma de México, México City 04510, Mexico; (L.T.A.-M.); (L.F.J.-G.)
| | - Iván Ortega-Blake
- Instituto de Ciencias Físicas, Universidad Nacional Autónoma de México, Apartado Postal 48-3, Cuernavaca 62251, Morelos, Mexico; (A.G.-H.); (L.D.-P.); (I.O.-B.)
| | - Bertha Espinoza
- Laboratorio de Estudios Sobre Tripanosomiasis y Leishmaniasis, Departamento de Inmunología, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, México City 04510, Mexico; (I.M.); (L.R.-S.); (K.D.R.-H.); (L.T.-M.)
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8
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Efimova SS, Ostroumova OS. Antibiotic Loaded Phytosomes as a Way to Develop Innovative Lipid Formulations of Polyene Macrolides. Pharmaceutics 2024; 16:665. [PMID: 38794328 PMCID: PMC11124810 DOI: 10.3390/pharmaceutics16050665] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2024] [Revised: 05/06/2024] [Accepted: 05/14/2024] [Indexed: 05/26/2024] Open
Abstract
BACKGROUND The threat of antibiotic resistance of fungal pathogens and the high toxicity of the most effective drugs, polyene macrolides, force us to look for new ways to develop innovative antifungal formulations. OBJECTIVE The aim of this study was to determine how the sterol, phospholipid, and flavonoid composition of liposomal forms of polyene antibiotics, and in particular, amphotericin B (AmB), affects their ability to increase the permeability of lipid bilayers that mimic the membranes of mammalian and fungal cells. METHODS To monitor the membrane permeability induced by various polyene-based lipid formulations, a calcein leakage assay and the electrophysiological technique based on planar lipid bilayers were used. KEY RESULTS The replacement of cholesterol with its biosynthetic precursor, 7-dehydrocholesterol, led to a decrease in the ability of AmB-loaded liposomes to permeabilize lipid bilayers mimicking mammalian cell membranes. The inclusion of plant flavonoid phloretin in AmB-loaded liposomes increased the ability of the formulation to disengage a fluorescent marker from lipid vesicles mimicking the membranes of target fungi. I-V characteristics of the fungal-like lipid bilayers treated with the AmB phytosomes were symmetric, demonstrating the functioning of double-length AmB pores and assuming a decrease in the antibiotic threshold concentration. CONCLUSIONS AND PERSPECTIVES The therapeutic window of polyene lipid formulations might be expanded by varying their sterol composition. Polyene-loaded phytosomes might be considered as the prototypes for innovative lipid antibiotic formulations.
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Affiliation(s)
- Svetlana S. Efimova
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology of Russian Academy of Sciences, Tikhoretsky Ave. 4, 194064 St. Petersburg, Russia;
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9
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Umegawa Y, Kato S, Seo S, Shinoda W, Kawatake S, Matsuoka S, Murata M. Protein-lipid acyl chain interactions: Depth-dependent changes of segmental mobility of phospholipid in contact with bacteriorhodopsin. Biophys Chem 2024; 308:107204. [PMID: 38412762 DOI: 10.1016/j.bpc.2024.107204] [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: 12/02/2023] [Revised: 01/31/2024] [Accepted: 02/20/2024] [Indexed: 02/29/2024]
Abstract
Boundary lipids surrounding membrane proteins play an essential role in protein function and structure. These protein-lipid interactions are mainly divided into electrostatic interactions between the polar amino acids of proteins and polar heads of phospholipids, and hydrophobic interactions between protein transmembrane sites and phospholipid acyl chains. Our previous report (Kawatake et al., Biochim. Biophys. Acta 1858 [2016] 2106-2115) covered a method for selectively analyzing boundary lipid interactions and showed differences in membrane protein-peripheral lipid interactions due to differences in their head group. Interactions in the hydrophobic acyl chains of phospholipids are relatively consistent among proteins, but the details of these interactions have not been elucidated. In this study, we reconstituted bacteriorhodopsin as a model protein into phospholipid membranes labeled with 2H and 13C for solid-state NMR measurement to investigate the depth-dependent effect of the head group structure on the lipid bilayer. The results showed that the position of the phospholipid near the carbonyl carbon was affected by the head group in terms of selectivity for protein surfaces, whereas in the deep interior of the bilayer near the leaflet interface, there was little difference between the head groups, indicating that the dependence of their interactions on the head group was much reduced.
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Affiliation(s)
- Yuichi Umegawa
- JST-ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Forefront Research Center, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
| | - Sho Kato
- JST-ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Sangjae Seo
- Department of Materials Chemistry, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan; Division of Supercomputing, Korea Institute of Science and Technology Information, 245 Daehak-ro, Yuseong-gu, Daejeon 34141, South Korea
| | - Wataru Shinoda
- Department of Materials Chemistry, Nagoya University, Furo-cho, Chikusa-ku, Nagoya 464-8603, Japan; Research Institute for Interdisciplinary Science, Okayama University, 3-1-1, Tsushima-naka, Okayama 700-8530, Japan
| | - Satoshi Kawatake
- JST-ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Forefront Research Center, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Shigeru Matsuoka
- JST-ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Forefront Research Center, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Michio Murata
- JST-ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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10
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Dixit M, Hajari T, Meti MD, Srivastava S, Srivastava A, Daniel J. Ionic Pairing and Selective Solvation of Butylmethylimidazolium Chloride Ion Pairs in DMSO-Water Mixtures: A Comprehensive Examination via Molecular Dynamics Simulations and Potentials of Mean Force Analysis. J Phys Chem B 2024; 128:2168-2180. [PMID: 38415290 DOI: 10.1021/acs.jpcb.3c06876] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/29/2024]
Abstract
Ionic liquids (ILs) with dimethyl sulfoxide (DMSO) and water act as a promising solvent medium for the dissolution of cellulose in an efficient manner. To develop a proper solvent system, it is really important to understand the thermodynamics of the molecular solutions consisting of ILs, DMSO, and water. The ion-pairing propensity of the ILs in the presence of DMSO and water plays a crucial role in governing the property of the solvent mixtures. Employing all-atom molecular dynamics simulations, we estimate the potentials of mean force between BMIM+ and Cl- ions in DMSO-water mixtures. Analysis reveals a significant increase in the thermodynamic stability of both contact ion pair (CIP) and solvent-assisted ion pair (SAIP) states with a rising DMSO mole fraction. Thermodynamic assessments highlight the entropic stabilization of CIP states and SAIP states in pure water, in DMSO-water mixtures, and in pure DMSO. The structural analysis reveals that in comparison to the DMSO local density, the local water density is relatively very high around ion pairs, more specifically in the solvation shell of a chloride ion. Preferential binding coefficients also consistently indicate exclusion of DMSO from the ion pair in DMSO-water mixtures. To enhance our understanding regarding the solvent molecules kinetics around the ion pairs, the survival probabilities of DMSO and water are computed. The calculations reveal that the water molecules prefer a prolonged stay in the solvation shell of Cl- ions.
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Affiliation(s)
- Mayank Dixit
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Timir Hajari
- Department of Chemistry, City College, 102/1, Raja Rammohan Sarani, Kolkata - 700009, India
| | - Manjunath D Meti
- Bio-physical Laboratory, Department of Plant Sciences, School of Life Sciences, University of Hyderabad, Hyderabad, Telangana 500046, India
| | - Srishti Srivastava
- Department of Zoology, Allahabad University, Prayagraj, Uttar Pradesh 211002, India
| | - Amar Srivastava
- Chemistry Department, Har Sahai (PG) College, Kanpur, Uttar Pradesh 208012, India
| | - Joseph Daniel
- Department of Chemistry, Christ Church College, Kanpur 208001, India
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11
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Jain VK, Jain K, Popli H. Conjugates of amphotericin B to resolve challenges associated with its delivery. Expert Opin Drug Deliv 2024; 21:187-210. [PMID: 38243810 DOI: 10.1080/17425247.2024.2308073] [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: 08/23/2023] [Accepted: 01/17/2024] [Indexed: 01/22/2024]
Abstract
INTRODUCTION Amphotericin B (AmB), a promising antifungal and antileishmanial drug, acts on the membrane of microorganisms. The clinical use of AmB is limited due to issues associated with its delivery including poor solubility and bioavailability, instability in acidic media, poor intestinal permeability, dose and aggregation state dependent toxicity, parenteral administration, and requirement of cold chain for transport and storage, etc. AREAS COVERED Scientists have formulated and explored various covalent conjugates of AmB to reduce its toxicity with increase in solubility, oral bioavailability, and payload or loading of AmB by using various polymers, lipids, carbon-based nanocarriers, metallic nanoparticles, and vesicular carriers, etc. In this article, we have reviewed various conjugates of AmB with polymers and nanomaterials explored for its delivery to give a deep insight regarding further exploration in future. EXPERT OPINION Covalent conjugates of AmB have been investigated by scientists, and preliminary in vitro and animal investigations have given successful results, which are required to be validated further with systematic investigation on safety and therapeutic efficacy in animals followed by clinical trials.
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Affiliation(s)
- Vineet Kumar Jain
- Department of Pharmaceutics, Delhi Pharmaceutical Sciences and Research University (DPSRU), New Delhi, India
| | - Keerti Jain
- Drug Delivery and Nanomedicine Research Laboratory, Department of Pharmaceutics, National Institute of Pharmaceutical Education and Research (NIPER) - Raebareli, Lucknow, India
| | - Harvinder Popli
- Department of Pharmaceutics, Delhi Pharmaceutical Sciences and Research University (DPSRU), New Delhi, India
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12
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Ostroumova OS, Efimova SS. Lipid-Centric Approaches in Combating Infectious Diseases: Antibacterials, Antifungals and Antivirals with Lipid-Associated Mechanisms of Action. Antibiotics (Basel) 2023; 12:1716. [PMID: 38136750 PMCID: PMC10741038 DOI: 10.3390/antibiotics12121716] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 12/05/2023] [Accepted: 12/08/2023] [Indexed: 12/24/2023] Open
Abstract
One of the global challenges of the 21st century is the increase in mortality from infectious diseases against the backdrop of the spread of antibiotic-resistant pathogenic microorganisms. In this regard, it is worth targeting antibacterials towards the membranes of pathogens that are quite conservative and not amenable to elimination. This review is an attempt to critically analyze the possibilities of targeting antimicrobial agents towards enzymes involved in pathogen lipid biosynthesis or towards bacterial, fungal, and viral lipid membranes, to increase the permeability via pore formation and to modulate the membranes' properties in a manner that makes them incompatible with the pathogen's life cycle. This review discusses the advantages and disadvantages of each approach in the search for highly effective but nontoxic antimicrobial agents. Examples of compounds with a proven molecular mechanism of action are presented, and the types of the most promising pharmacophores for further research and the improvement of the characteristics of antibiotics are discussed. The strategies that pathogens use for survival in terms of modulating the lipid composition and physical properties of the membrane, achieving a balance between resistance to antibiotics and the ability to facilitate all necessary transport and signaling processes, are also considered.
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Affiliation(s)
- Olga S. Ostroumova
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology, Russian Academy of Sciences, Tikhoretsky Ave. 4, St. Petersburg 194064, Russia;
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13
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Watanabe H, Hanashima S, Yano Y, Yasuda T, Murata M. Passive Translocation of Phospholipids in Asymmetric Model Membranes: Solid-State 1H NMR Characterization of Flip-Flop Kinetics Using Deuterated Sphingomyelin and Phosphatidylcholine. LANGMUIR : THE ACS JOURNAL OF SURFACES AND COLLOIDS 2023; 39:15189-15199. [PMID: 37729012 DOI: 10.1021/acs.langmuir.3c01650] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 09/22/2023]
Abstract
Although lateral and inter-leaflet lipid-lipid interactions in cell membranes play roles in maintaining asymmetric lipid bilayers, the molecular basis of these interactions is largely unknown. Here, we established a method to determine the distribution ratio of phospholipids between the outer and inner leaflets of asymmetric large unilamellar vesicles (aLUVs). The trimethylammonium group, (CH3)3N+, in the choline headgroup of N-palmitoyl-sphingomyelin (PSM) and 1,2-dioleoyl-sn-glycero-3-phosphatidylcholine (DOPC) gave rise to a relatively sharp signal in magic-angle spinning solid-state 1H NMR (MAS-ss-1H NMR). PSM and DOPC have the same headgroup structure, but one phospholipid was selectively observed by deuterating the trimethylammonium group of the other phospholipid. The addition of Pr3+ to the medium surrounding aLUVs selectively shifted the chemical shift of the (CH3)3N+ group in the outer leaflet from that in the inner leaflet, which allowed estimation of the inter-leaflet distribution ratio of the unlabeled lipid in aLUVs. Using this method, we evaluated the translocation of PSM and DOPC between the outer and inner leaflets of the cholesterol-containing aLUVs, with PSM and DOPC mostly distributed in the outer and inner leaflets, respectively, immediately after aLUV preparation; their flip and flop rates were approximately 2.7 and 6.4 × 10-6 s-1, respectively. During the passive symmetrization of aLUVs, the lipid translocation rate was decreased due to changes in the membrane order, probably through the formation of the registered liquid-ordered domains. Comparison of the result with that of symmetric LUVs revealed that lipid asymmetry may not significantly affect the lipid translocation rates, while the lateral lipid-lipid interaction may be a dominant factor in lipid translocation under these conditions. These findings highlight the importance of considering the effects of lateral lipid interactions within the same leaflet on lipid flip-flop rates when evaluating the asymmetry of phospholipids in the cell membrane.
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Affiliation(s)
- Hirofumi Watanabe
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan
| | - Shinya Hanashima
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan
- Graduate School of Engineering, Tottori University, 4-101 Koyama-cho Minami, Tottori 680-8550, Japan
| | - Yo Yano
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan
| | - Tomokazu Yasuda
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan
- Forefront Research Center, Graduate School of Science, Osaka University, Toyonaka 560-0043, Osaka, Japan
| | - Michio Murata
- Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka 560-0043, Osaka, Japan
- Forefront Research Center, Graduate School of Science, Osaka University, Toyonaka 560-0043, Osaka, Japan
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14
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Dixit M, Taniguchi T. Role of Terminal Groups of cis-1,4-Polyisoprene Chains in the Formation of Physical Junction Points in Natural Rubber. Biomacromolecules 2023; 24:3589-3602. [PMID: 37527033 DOI: 10.1021/acs.biomac.3c00355] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 08/03/2023]
Abstract
The terminal structures of cis-1,4-polyisoprene (PI) chains play a vital role in the excellent comprehensive performance of Hevea natural rubber (NR) with properties such as high toughness, tear-resistance, and wet skid resistance. The cis-1,4-polyisoprene chain constituting NR exhibits a distinct composition of terminal groups comprising two distinct types, namely, the ω and α terminal groups. The structures of the ω terminal [dimethyl allyl (DMA)-(trans-1,4-isoprene)2] and six kinds of α end groups of the polymer chain of NR have been explored by utilizing a newly developed 2D NMR method. In the present work, we examine different kinds of PI melt systems, and we choose various combinations of terminal groups: Hydrogen, one DMA unit with two trans isoprene units as ω end groups and ester-terminated isopentene (α1), hydroxy-terminated isopentene (α2), ester-terminated isobutane (α3), hydroxy-terminated isobutane (α4), ester-terminated 1,4-cis-isoprene (α5), and hydroxy-terminated 1,4-cis-isoprene (α6), i.e., HPIH (PI0)-pure PI (Hydrogen terminal), ωPIα1 (PII), ωPIα2 (PIII), ωPIα3 (PIIII), ωPIα4 (PIIV), ωPIα5 (PIV), and ωPIα6 (PIVI). We evaluated dynamic and static properties of PI chains such as the end-to-end vector autocorrelation function (C(t)), its average relaxation time (τ), end-to-end distance (Ree), and radius of gyration (Rg). We also estimated the diffusion coefficients of polyisoprene chains and pair correlation functions [radial distribution functions (RDFs)], potentials of mean force (PMFs) in between end residues, and survival probability (P(τ)) of end groups around the end group by analyzing the equilibrated trajectories of full-atom MD simulations. As per the examination of C(t), rotational relaxation time τ, and RDFs, we discovered that the existence of a strong hydrogen bond in α2-α2, α4-α4, and α6-α6 residues makes the dynamics of hydroxy-terminated polyisoprene chains in ωPIα2,α4,α6 melt systems slower. From the analyses of RDFs and PMFs (W(r)), the association between [α2]-[α2], [α4]-[α4], and [α6]-[α6] terminals in ωPIα2,α4,α6 melt systems is significantly stronger than in [ISO]-[ISO] [Hydrogen terminated 1,4-cis-isoprene:(ISO)] in HPIH and ω-ω, [α1]-[α1], [α3]-[α3], and [α5]-[α5] in ωPIα1,α3,α5 systems. We quantified the fraction of cluster formation of terminal groups of a given size in the seven PI melt systems by employing the criteria of PMFs. It is revealed that no stable cluster exists in the HPIH, ωPIα1, ωPIα3, and ωPIα5 melt systems. Conversely, in the ωPIα2, ωPIα4, and ωPIα6 systems, we perceived stable clusters of [(α2)p] [(α4)p] and [(α6)p] end groups where p (2 ≤ x ≤ 6). These stable clusters validate the presence of physical junction points in between hydroxy-terminated polyisoprene chains through their α2, α4, and α6 terminals. These physical junction points might be crucial for superior properties of NR such as high toughness, crack growth resistance, and strain-induced crystallization.
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Affiliation(s)
- Mayank Dixit
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
| | - Takashi Taniguchi
- Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto 615-8510, Japan
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15
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Efimova SS, Malykhina AI, Ostroumova OS. Triggering the Amphotericin B Pore-Forming Activity by Phytochemicals. MEMBRANES 2023; 13:670. [PMID: 37505036 PMCID: PMC10384262 DOI: 10.3390/membranes13070670] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 07/29/2023]
Abstract
The macrolide polyene antibiotic amphotericin B (AmB), remains a valuable drug to treat systemic mycoses due to its wide antifungal activity and low probability of developing resistance. The high toxicity of AmB, expressed in nephropathy and hemolysis, could be partially resolved by lowering therapeutic AmB concentration while maintaining efficacy. This work discusses the possibility of using plant polyphenols and alkaloids to enhance the pore-forming and consequently antifungal activity of AmB. We demonstrated that phloretin, phlorizin, naringenin, taxifolin, quercetin, biochanin A, genistein, resveratrol, and quinine led to an increase in the integral AmB-induced transmembrane current in the bilayers composed of palmitoyloleoylphosphocholine and ergosterol, while catechin, colchicine, and dihydrocapsaicin did not practically change the AmB activity. Cardamonin, 4'-hydroxychalcone, licochalcone A, butein, curcumin, and piperine inhibited AmB-induced transmembrane current. Absorbance spectroscopy revealed no changes in AmB membrane concentration with phloretin addition. A possible explanation of the potentiation is related to the phytochemical-produced changes in the elastic membrane properties and the decrease in the energy of formation of the lipid mouth of AmB pores, which is partially confirmed by differential scanning microcalorimetry. The possibility of AmB interaction with cholesterol in the mammalian cell membranes instead of ergosterol in fungal membranes, determines its high toxicity. The replacement of ergosterol with cholesterol in the membrane lipid composition led to a complete loss or a significant decrease in the potentiating effects of tested phytochemicals, indicating low potential toxicity of these compounds and high therapeutic potential of their combinations with the antibiotic. The discovered combinations of AmB with plant molecules that enhance its pore-forming ability in ergosterol-enriched membranes, seem to be promising for further drug development in terms of the toxicity decrease and efficacy improvement.
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Affiliation(s)
- Svetlana S Efimova
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology of Russian Academy of Sciences, Tikhoretsky 4, 194064 Saint Petersburg, Russia
| | - Anna I Malykhina
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology of Russian Academy of Sciences, Tikhoretsky 4, 194064 Saint Petersburg, Russia
| | - Olga S Ostroumova
- Laboratory of Membrane and Ion Channel Modeling, Institute of Cytology of Russian Academy of Sciences, Tikhoretsky 4, 194064 Saint Petersburg, Russia
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16
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Janik S, Grela E, Stączek S, Zdybicka-Barabas A, Luchowski R, Gruszecki WI, Grudzinski W. Amphotericin B-Silver Hybrid Nanoparticles Help to Unveil the Mechanism of Biological Activity of the Antibiotic: Disintegration of Cell Membranes. Molecules 2023; 28:4687. [PMID: 37375242 DOI: 10.3390/molecules28124687] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/17/2023] [Revised: 06/05/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
Amphotericin B is a popular antifungal antibiotic, and despite decades of pharmacological application, the exact mode of its biological activity is still a matter of debate. Amphotericin B-silver hybrid nanoparticles (AmB-Ag) have been reported to be an extremely effective form of this antibiotic to combat fungi. Here, we analyze the interaction of AmB-Ag with C. albicans cells with the application of molecular spectroscopy and imaging techniques, including Raman scattering and Fluorescence Lifetime Imaging Microscopy. The results lead to the conclusion that among the main molecular mechanisms responsible for the antifungal activity of AmB is the disintegration of the cell membrane, which occurs on a timescale of minutes.
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Affiliation(s)
- Sebastian Janik
- Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin, Poland
| | - Ewa Grela
- Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin, Poland
- Division of Biophysics, Institute of Experimental Physics, Faculty of Physics, University of Warsaw, 02-093 Warsaw, Poland
| | - Sylwia Stączek
- Department of Immunobiology, Faculty of Biology and Biotechnology, Institute of Biological Sciences, Maria Curie-Sklodowska University, 20-031 Lublin, Poland
| | - Agnieszka Zdybicka-Barabas
- Department of Immunobiology, Faculty of Biology and Biotechnology, Institute of Biological Sciences, Maria Curie-Sklodowska University, 20-031 Lublin, Poland
| | - Rafal Luchowski
- Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin, Poland
| | - Wieslaw I Gruszecki
- Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin, Poland
| | - Wojciech Grudzinski
- Department of Biophysics, Institute of Physics, Maria Curie-Sklodowska University, 20-031 Lublin, Poland
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17
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Zhu P, Li Y, Guo T, Liu S, Tancer RJ, Hu C, Zhao C, Xue C, Liao G. New antifungal strategies: drug combination and co-delivery. Adv Drug Deliv Rev 2023; 198:114874. [PMID: 37211279 DOI: 10.1016/j.addr.2023.114874] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2023] [Revised: 05/12/2023] [Accepted: 05/14/2023] [Indexed: 05/23/2023]
Abstract
The growing occurrence of invasive fungal infections and the mounting rates of drug resistance constitute a significant menace to human health. Antifungal drug combinations have garnered substantial interest for their potential to improve therapeutic efficacy, reduce drug doses, reverse, or ameliorate drug resistance. A thorough understanding of the molecular mechanisms underlying antifungal drug resistance and drug combination is key to developing new drug combinations. Here we discuss the mechanisms of antifungal drug resistance and elucidate how to discover potent drug combinations to surmount resistance. We also examine the challenges encountered in developing such combinations and discuss prospects, including advanced drug delivery strategies.
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Affiliation(s)
- Ping Zhu
- State Key Laboratory of Silkworm Genome Biology, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400700, China
| | - Yan Li
- Beijing Key Laboratory of Antimicrobial Agents, Institute of Medicinal Biotechnology, Peking Union Medical College and Chinese Academy of Medical Sciences, Beijing 100050, China
| | - Ting Guo
- State Key Laboratory of Silkworm Genome Biology, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400700, China
| | - Simei Liu
- Department of Traditional Chinese Medicine, Chongqing College of Traditional Chinese Medicine, Chongqing 402760, China; Institute of Pharmacology and Toxicology, Chongqing Academy of Chinese Materia Medica, Chongqing 400065, China
| | - Robert J Tancer
- Public Health Research Institute and Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Changhua Hu
- State Key Laboratory of Silkworm Genome Biology, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400700, China
| | - Chengzhi Zhao
- Chongqing Health Center for Women and Children, Chongqing, 400700, PR China.
| | - Chaoyang Xue
- Public Health Research Institute and Department of Microbiology, Biochemistry and Molecular Genetics, New Jersey Medical School, Rutgers University, Newark, NJ, 07103, USA
| | - Guojian Liao
- State Key Laboratory of Silkworm Genome Biology, College of Pharmaceutical Sciences, Southwest University, Chongqing, 400700, China.
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18
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Fridman M, Sakurai K. Deciphering the Biological Activities of Antifungal Agents with Chemical Probes. Angew Chem Int Ed Engl 2023; 62:e202211927. [PMID: 36628503 DOI: 10.1002/anie.202211927] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2022] [Revised: 11/09/2022] [Accepted: 01/10/2023] [Indexed: 01/12/2023]
Abstract
The growing number of fungal infections caused by pathogens resistant to one or more classes of antifungal drugs emphasizes the threat that these microorganisms pose to animal and human health and global food security. Open questions remain regarding the mechanisms of action of the limited repertoire of antifungal agents, making it challenging to rationally develop more efficacious therapeutics. In recent years, the use of chemical biology approaches has resolved some of these questions and has provided new promising concepts to guide the design of antifungal agents. By focusing on examples from studies carried out in recent years, this minireview describes the key roles that probes based on antifungal agents and their derivatives have played in uncovering details about their activities, in detecting resistance, and in characterizing the interactions between these agents and their targets.
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Affiliation(s)
- Micha Fridman
- School of Chemistry, Raymond & Beverly Sackler Faculty of Exact Sciences, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Kaori Sakurai
- Department of Biotechnology and Life Science, Tokyo University of Agriculture and Technology, 4-24-16, Naka-cho, Koganei-shi, Tokyo, 184-8588, Japan
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19
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Ondevilla JC, Hanashima S, Mukogawa A, Miyazato DG, Umegawa Y, Murata M. Effect of the number of sugar units on the interaction between diosgenyl saponin and membrane lipids. BIOCHIMICA ET BIOPHYSICA ACTA. BIOMEMBRANES 2023; 1865:184145. [PMID: 36914020 DOI: 10.1016/j.bbamem.2023.184145] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Revised: 03/01/2023] [Accepted: 03/01/2023] [Indexed: 03/15/2023]
Abstract
Saponin is the main bioactive component of the Dioscorea species, which are traditionally used for treating chronic diseases. An understanding of the interaction process of bioactive saponins with biomembranes provides insights into their development as therapeutic agents. The biological effects of saponins have been thought to be associated with membrane cholesterol (Chol). To shed light on the exact mechanisms of their interactions, we investigated the effects of diosgenyl saponins trillin (TRL) and dioscin (DSN) on the dynamic behavior of lipids and membrane properties in palmitoyloleolylphosphatidylcholine (POPC) bilayers using solid-state NMR and fluorescence spectroscopy. The membrane effects of diosgenin, a sapogenin of TRL and DSN, are similar to those of Chol, suggesting that diosgenin plays a major role in membrane binding and POPC chain ordering. The amphiphilicity of TRL and DSN enabled them to interact with POPC bilayers, regardless of Chol. In the presence of Chol, the sugar residues more prominently influenced the membrane-disrupting effects of saponins. The activity of DSN, which bears three sugar units, led to perturbation and further disruption of the membrane in the presence of Chol. However, TRL, which bears one sugar residue, increased the ordering of POPC chains while maintaining the integrity of the bilayer. This effect on the phospholipid bilayers is similar to that of cholesteryl glucoside. The influence of the number of sugars in saponin is discussed in more detail.
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Affiliation(s)
- Joan Candice Ondevilla
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, De La Salle University, 2401 Taft Avenue, Manila 0922, Philippines
| | - Shinya Hanashima
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry and Biotechnology, Graduate School of Engineering, Tottori University, 4-101 Koyama-cho Minami, Tottori 680-8552, Japan.
| | - Akane Mukogawa
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Darcy Garza Miyazato
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Yuichi Umegawa
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Forefront Research Centre for Fundamental Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan
| | - Michio Murata
- Department of Chemistry, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan; Forefront Research Centre for Fundamental Science, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043, Japan.
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Ji X, Shi C, Guo D, Yang X, Suo L, Luo J. Engineering Telodendrimer Nanocarriers for Monomeric Amphotericin B Delivery. Mol Pharm 2023; 20:2138-2149. [PMID: 36877183 DOI: 10.1021/acs.molpharmaceut.2c01087] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
Systemic fungal infections are an increasingly prevalent health problem. Amphotericin B (AmB), a hydrophobic polyene antibiotic, remains the drug of choice for life-threatening invasive fungal infections. However, it has dose-limiting side effects, including nephrotoxicity. The efficacy and toxicity of AmB are directly related to its aggregation state. Here, we report the preparation of a series of telodendrimer (TD) nanocarriers with the freely engineered core structures for AmB encapsulation to fine-tune AmB aggregation status. The reduced aggregation status correlates well with the optimized antifungal activity, attenuated hemolytic properties, and reduced cytotoxicity to mammalian cells. The optimized TD nanocarrier for monomeric AmB encapsulation significantly increases the therapeutic index, reduces the in vivo toxicity, and enhances antifungal effects in mouse models with Candida albicans infection in comparison to two common clinical formulations, i.e., Fungizone and AmBisome.
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Affiliation(s)
- Xiaotian Ji
- Department of Pharmacology, State University of New York Upstate Medical University, Syracuse, New York 13210, United States
| | - Changying Shi
- Department of Pharmacology, State University of New York Upstate Medical University, Syracuse, New York 13210, United States
| | - Dandan Guo
- Department of Pharmacology, State University of New York Upstate Medical University, Syracuse, New York 13210, United States
| | - Xiguang Yang
- Department of Pharmacology, State University of New York Upstate Medical University, Syracuse, New York 13210, United States
| | - Liye Suo
- Department of Pathology, State University of New York Upstate Medical University, Syracuse, New York 13210, United States
| | - Juntao Luo
- Department of Pharmacology, Department of Surgery, Department of Microbiology and Immunology, Upstate Cancer Center, Upstate Sepsis Interdisciplinary Research Center, State University of New York Upstate Medical University, Syracuse, New York 13210, United States
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21
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Umegawa Y, Kawatake S, Murata M, Matsuoka S. Combined effect of the head groups and alkyl chains of archaea lipids when interacting with bacteriorhodopsin. Biophys Chem 2023; 294:106959. [PMID: 36709544 DOI: 10.1016/j.bpc.2023.106959] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/25/2022] [Revised: 01/12/2023] [Accepted: 01/16/2023] [Indexed: 01/21/2023]
Abstract
Bacteriorhodopsin (bR), a transmembrane protein with seven α-helices, is highly expressed in the purple membrane (PM) of archaea such as Halobacterium salinarum. It is well known that bR forms two-dimensional crystals with acidic lipids such as phosphatidylglycerol phosphate methyl ester (PGP-Me)-a major component of PM lipids bearing unique chemical structures-methyl-branched alkyl chains, ether linkages, and divalent anionic head groups with two phosphodiester groups. Therefore, we aimed to determine which functional groups of PGP-Me are essential for the boundary lipids of bR and how these functionalities interact with bR. To this end, we compared various well-known phospholipids (PLs) that carry one of the structural features of PGP-Me, and evaluated the affinity of PLs to bR using the centerband-only analysis of rotor-unsynchronized spin echo (COARSE) method in solid-state NMR measurements and thermal shift assays. The results clearly showed that the branched methyl groups of alkyl chains and double negative charges in the head groups are important for PL interactions with bR. We then examined the effect of phospholipids on the monomer-trimer exchange of bR using circular dichroism (CD) spectra. The results indicated that the divalent negative charge in a head group stabilizes the trimer structure, while the branched methyl chains significantly enhance the PLs' affinity for bR, thus dispersing bR trimers in the PM even at high concentrations. Finally, we investigated the effects of PL on the proton-pumping activity of bR based on the decay rate constant of the M intermediate of a bR photocycle. The findings showed that bR activities decreased to 20% in 1,2-dimyristoyl-sn-glycero-3-phosphate (DMPA), and in 1,2-diphytanoyl-sn-glycero-3-phosphocholine (DPhPC) bilayers as compared to that in PM. Meanwhile, 1,2-Diphytanoyl-sn-glycero-3-phosphate (DPhPA) bilayers bearing both negative charges and branched methyl groups preserved over 80% of the activity. These results strongly suggest that the head groups and alkyl chains of phospholipids are essential for boundary lipids and greatly influence the biological function of bR.
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Affiliation(s)
- Yuichi Umegawa
- JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Forefront Research Center, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan.
| | - Satoshi Kawatake
- JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Forefront Research Center, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Michio Murata
- JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
| | - Shigeru Matsuoka
- JST ERATO, Lipid Active Structure Project, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Department of Chemistry, Graduate School of Science, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan; Forefront Research Center, Osaka University, 1-1 Machikaneyama, Toyonaka, Osaka 560-0043, Japan
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22
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Komaki K, Kasuya S, Toda Y, Tosaka T, Kamiya K, Koshiyama T. Cu(II)-Triggered Ion Channel Properties of a 2,2'-Bipyridine-Modified Amphotericin B. ACS APPLIED BIO MATERIALS 2023; 6:828-835. [PMID: 36708326 DOI: 10.1021/acsabm.2c00995] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
The development of stimuli-responsive synthetic channels that open and close in response to physical and chemical changes in the surrounding environment has attracted attention because of their potential bioapplications such as sensing, drug release, antibiotics, and molecular manipulation tools to control membrane transport in cells. Metal coordination is ideal as a stimulus for stimuli-responsive channels because it allows for reversible gating behavior through the addition and removal of metal ions and fine-tuning of channel structure through coordination geometry defined by the type of the metal ion and ligand. We have previously reported on transition metal-ion dependent ion permeability control of Amphotericin B (AmB) modified with a metal coordination site, 2,2'-bipyridine ligand (bpy-AmB). AmB is one of the polyene macrolide antibiotics, and it is known that the interaction between AmB and ergosterol molecules is required for AmB channel formation. In contrast, the Cu2+ coordination to the bpy moiety of bpy-AmB induces formation of Ca2+ ion-permeable channels in the ergosterol-free POPC membrane. However, the details of bpy-AmB properties such as channel stability, ion selectivity, pore size, and the effect of ergosterol on channel formation remain unclear. Here, we investigate bpy-AmB channels triggered by transition metal coordination in POPC or ergosterol-containing POPC liposomes using an HPTS assay, electrophysiological measurements, and time-resolved UV-vis spectral measurements. These analyses reveal that bpy-AmB channels triggered by Cu2+ ions are more stable and have larger pore sizes than the original AmB channels and enable efficient permeation of various cations. We believe that our channel design will lead to the construction of metal coordination-triggered synthetic ion channels.
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Affiliation(s)
- Kosuke Komaki
- Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, 1-1-1, Noji-higashi, Kusatsu, Shiga525-8577, Japan
| | - Soichiro Kasuya
- Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, 1-1-1, Noji-higashi, Kusatsu, Shiga525-8577, Japan
| | - Yusei Toda
- Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, 1-1-1, Noji-higashi, Kusatsu, Shiga525-8577, Japan
| | - Toshiyuki Tosaka
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, 1-5-1, Tenjin, Kiryu, Gunma376-8515, Japan
| | - Koki Kamiya
- Division of Molecular Science, Graduate School of Science and Technology, Gunma University, 1-5-1, Tenjin, Kiryu, Gunma376-8515, Japan
| | - Tomomi Koshiyama
- Department of Applied Chemistry, College of Life Sciences, Ritsumeikan University, 1-1-1, Noji-higashi, Kusatsu, Shiga525-8577, Japan
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Semisynthetic Amides of Amphotericin B and Nystatin A 1: A Comparative Study of In Vitro Activity/Toxicity Ratio in Relation to Selectivity to Ergosterol Membranes. Antibiotics (Basel) 2023; 12:antibiotics12010151. [PMID: 36671352 PMCID: PMC9854944 DOI: 10.3390/antibiotics12010151] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2022] [Revised: 12/24/2022] [Accepted: 01/05/2023] [Indexed: 01/15/2023] Open
Abstract
Polyene antifungal amphotericin B (AmB) has been used for over 60 years, and remains a valuable clinical treatment for systemic mycoses, due to its broad antifungal activity and low rate of emerging resistance. There is no consensus on how exactly it kills fungal cells but it is certain that AmB and the closely-related nystatin (Nys) can form pores in membranes and have a higher affinity towards ergosterol than cholesterol. Notably, the high nephro- and hemolytic toxicity of polyenes and their low solubility in water have led to efforts to improve their properties. We present the synthesis of new amphotericin and nystatin amides and a comparative study of the effects of identical modifications of AmB and Nys on the relationship between their structure and properties. Generally, increases in the activity/toxicity ratio were in good agreement with increasing ratios of selective permeabilization of ergosterol- vs. cholesterol-containing membranes. We also show that the introduced modifications had an effect on the sensitivity of mutant yeast strains with alterations in ergosterol biosynthesis to the studied polyenes, suggesting a varying affinity towards intermediate ergosterol precursors. Three new water-soluble nystatin derivatives showed a prominent improvement in safety and were selected as promising candidates for drug development.
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Chromone-Containing Allylmorpholines Influence Ion Channels in Lipid Membranes via Dipole Potential and Packing Stress. Int J Mol Sci 2022; 23:ijms231911554. [PMID: 36232854 PMCID: PMC9570167 DOI: 10.3390/ijms231911554] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2022] [Revised: 09/23/2022] [Accepted: 09/27/2022] [Indexed: 11/17/2022] Open
Abstract
Herein, we report that chromone-containing allylmorpholines can affect ion channels formed by pore-forming antibiotics in model lipid membranes, which correlates with their ability to influence membrane boundary potential and lipid-packing stress. At 100 µg/mL, allylmorpholines 1, 6, 7, and 8 decrease the boundary potential of the bilayers composed of palmitoyloleoylphosphocholine (POPC) by about 100 mV. At the same time, the compounds do not affect the zeta-potential of POPC liposomes, but reduce the membrane dipole potential by 80-120 mV. The allylmorpholine-induced drop in the dipole potential produce 10-30% enhancement in the conductance of gramicidin A channels. Chromone-containing allylmorpholines also affect the thermotropic behavior of dipalmytoylphosphocholine (DPPC), abolishing the pretransition, lowering melting cooperativity, and turning the main phase transition peak into a multicomponent profile. Compounds 4, 6, 7, and 8 are able to decrease DPPC's melting temperature by about 0.5-1.9 °C. Moreover, derivative 7 is shown to increase the temperature of transition of palmitoyloleoylphosphoethanolamine from lamellar to inverted hexagonal phase. The effects on lipid-phase transitions are attributed to the changes in the spontaneous curvature stress. Alterations in lipid packing induced by allylmorpholines are believed to potentiate the pore-forming ability of amphotericin B and gramicidin A by several times.
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