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Multifunctional Pharmaceutical Effects of the Antibiotic Daptomycin. BIOMED RESEARCH INTERNATIONAL 2019; 2019:8609218. [PMID: 31263709 PMCID: PMC6556800 DOI: 10.1155/2019/8609218] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/21/2019] [Revised: 04/24/2019] [Accepted: 05/14/2019] [Indexed: 02/06/2023]
Abstract
Daptomycin (DAP), a cyclic lipopeptide produced by Streptomyces roseosporus, is a novel antibiotic to clinically treat various Gram-positive pathogenic bacteria-induced infections. Although DAP has a strong broad-spectrum bactericidal effect, recently rare bacterial antibiotic resistance against DAP gradually arises. The review is to summarize the normal indications of DAP, its off-label usage against several clinical pathogen infections, the unique antibacterial mechanisms of DAP, and the combination of antibiotic therapies for highly DAP-resistant pathogens. More noticeably, rising evidences demonstrate that DAP has new potential activity of anticancer and immunomodulatory effects. So far the multifunctional pharmaceutical effects of DAP deserve to be further explored for future clinical applications.
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Beriashvili D, Taylor R, Kralt B, Abu Mazen N, Taylor SD, Palmer M. Mechanistic studies on the effect of membrane lipid acyl chain composition on daptomycin pore formation. Chem Phys Lipids 2018; 216:73-79. [PMID: 30278162 DOI: 10.1016/j.chemphyslip.2018.09.015] [Citation(s) in RCA: 22] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2018] [Revised: 09/26/2018] [Accepted: 09/27/2018] [Indexed: 01/20/2023]
Abstract
Daptomycin is a lipopeptide antibiotic that binds and permeabilizes the cell membranes of Gram-positive bacteria. Membrane permeabilization requires both calcium and phosphatidylglycerol (PG) in the target membrane, and it correlates with the formation of an oligomer that likely comprises eight subunits, which are evenly distributed between the two membrane leaflets. In both bacterial cells and model membranes, changes in the fatty acyl composition of the membrane phospholipids can prevent permeabilization. We here used liposomes to study the effect of phospholipids containing oleoyl and other fatty acyl residues on daptomycin activity, and made the following observations: (1) Oleic acid residues inhibited permeabilization when part not only of PG, but also of other phospholipids (PC or cardiolipin). (2) When included in an otherwise daptomycin-susceptible lipid mixture, even 10% of dioleoyl lipid (DOPC) can strongly inhibit permeabilization. (3) The inhibitory effect of fatty acyl residues appears to correlate more with their chain length than with unsaturation. (4) Under all conditions tested, permeabilization coincided with octamer formation, whereas tetramers were observed on membranes that were not permeabilized. Overall, our findings further support the notion that the octamer is indeed the functional transmembrane pore, and that fatty acyl residues may prevent pore formation by preventing the alignment of tetramers across the two membrane leaflets.
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Affiliation(s)
- David Beriashvili
- Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
| | - Robert Taylor
- Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
| | - Braden Kralt
- Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
| | - Nooran Abu Mazen
- Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
| | - Scott D Taylor
- Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
| | - Michael Palmer
- Department of Chemistry, University of Waterloo, Waterloo, ON N2L 3G1, Canada.
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Barnawi G, Noden M, Taylor R, Lohani C, Beriashvili D, Palmer M, Taylor SD. An entirely fmoc solid phase approach to the synthesis of daptomycin analogs. Biopolymers 2018; 111. [PMID: 29293268 DOI: 10.1002/bip.23094] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2017] [Revised: 11/29/2017] [Accepted: 12/03/2017] [Indexed: 02/06/2023]
Abstract
Daptomycin is an important Ca2+ -dependent cyclic lipodepsipeptide antibiotic used to treat serious gram-positive infections. The search for daptomycin analogs with improved activity and their application as tools for studying its mechanism of action has prompted us to develop an entirely Fmoc solid phase approach to the synthesis of daptomycin analogs. Key to the success of this approach was the development of conditions that allowed for the formation of the ester bond on resin-bound peptides consisting of residues 1-10 and the decanoyl lipid tail. The esterification reaction proceeded more efficiently on Tentagel resin as opposed to standard polystyrene resin. This approach was used to synthesize a series of analogs in which each position of Dap-E12-W13, a relatively active daptomycin analog, was individually substituted by alanine. Only positions 2, 6, and 11 were found to be amenable to substitution by alanine in that the corresponding alanine analogs were only 1.5- to 4-fold less active than Dap-E12-W13. We also found that the daptomycin analog, Dap-K6-E12-W13, exhibits in vitro activity approaching that of daptomycin at physiological Ca2+ concentration. Studies with Dap-K6-E12-W13 and model liposomes indicate that this analog interacts with membranes by the same mechanism as daptomycin. This analog is currently being used as a lead for the development daptomycin analogs with improved activity.
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Affiliation(s)
- Ghufran Barnawi
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Michael Noden
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Robert Taylor
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Chuda Lohani
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - David Beriashvili
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Michael Palmer
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
| | - Scott D Taylor
- Department of Chemistry, University of Waterloo, 200 University Avenue West, Waterloo, Ontario, N2L 3G1, Canada
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Taylor R, Beriashvili D, Taylor S, Palmer M. Daptomycin Pore Formation Is Restricted by Lipid Acyl Chain Composition. ACS Infect Dis 2017; 3:797-801. [PMID: 29048870 DOI: 10.1021/acsinfecdis.7b00138] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Daptomycin is a calcium-dependent lipopeptide antibiotic that is used clinically against various Gram-positive pathogens. It acts on bacterial cell membranes, whose susceptibility varies with the content of phosphatidylglycerol (PG). Some studies have reported that daptomycin permeabilizes and depolarizes bacterial cell membranes, while others have found no evidence of membrane permeabilization and thus proposed different mechanisms of antibacterial action. Divergent observations have also been reported regarding the effect of daptomycin on model membranes, which were found to be permeabilized nonselectively, selectively for small cations, or not at all. While these diverging model studies did consider the functional roles of different lipid head groups, they assumed that the acyl chains were interchangeable. We here show this assumption to be erroneous. In equimolar mixtures of PG and phosphatidylcholine (PC), dimyristoyl lipids support membrane permeabilization, whereas dioleyl and palmitoleyl lipids do not, even though daptomycin does bind to and form oligomers on all of these membranes. These observations help reconcile some of the discrepant findings in the literature.
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Affiliation(s)
- Robert Taylor
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - David Beriashvili
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Scott Taylor
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
| | - Michael Palmer
- Department of Chemistry, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada
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