The microbiome-derived antibacterial lugdunin acts as a cation ionophore in synergy with host peptides.

Autor:	Berscheid A; Interfaculty Institute of Microbiology and Infection Medicine, Microbial Bioactive Compounds, University of Tübingen, Tübingen, Germany.; Microbial Bioactive Compounds, University of Tübingen, German Centre for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany., Straetener J; Interfaculty Institute of Microbiology and Infection Medicine, Microbial Bioactive Compounds, University of Tübingen, Tübingen, Germany., Schilling NA; Institute of Organic Chemistry, University of Tübingen, Tübingen, Germany., Ruppelt D; Georg-August-Universität Göttingen, Institute of Organic and Biomolecular Chemistry, Göttingen, Germany., Konnerth MC; Institute of Organic Chemistry, University of Tübingen, Tübingen, Germany., Schittek B; Department of Dermatology, Division of Dermatooncology, University of Tübingen, Tübingen, Germany., Krismer B; Microbial Bioactive Compounds, University of Tübingen, German Centre for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany.; Interfaculty Institute of Microbiology and Infection Medicine, Infection Biology, University of Tübingen, Tübingen, Germany.; Microbial Bioactive Compounds, University of Tübingen, Cluster of Excellence EXC 2124-Controlling Microbes to Fight Infections, Tubingen, Germany., Peschel A; Microbial Bioactive Compounds, University of Tübingen, German Centre for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany.; Interfaculty Institute of Microbiology and Infection Medicine, Infection Biology, University of Tübingen, Tübingen, Germany.; Microbial Bioactive Compounds, University of Tübingen, Cluster of Excellence EXC 2124-Controlling Microbes to Fight Infections, Tubingen, Germany., Steinem C; Georg-August-Universität Göttingen, Institute of Organic and Biomolecular Chemistry, Göttingen, Germany.; Max-Planck-Institute for Dynamics and Self Organization, Göttingen, Germany., Grond S; Institute of Organic Chemistry, University of Tübingen, Tübingen, Germany.; Microbial Bioactive Compounds, University of Tübingen, Cluster of Excellence EXC 2124-Controlling Microbes to Fight Infections, Tubingen, Germany., Brötz-Oesterhelt H; Interfaculty Institute of Microbiology and Infection Medicine, Microbial Bioactive Compounds, University of Tübingen, Tübingen, Germany.; Microbial Bioactive Compounds, University of Tübingen, German Centre for Infection Research (DZIF), Partner Site Tübingen, Tübingen, Germany.; Microbial Bioactive Compounds, University of Tübingen, Cluster of Excellence EXC 2124-Controlling Microbes to Fight Infections, Tubingen, Germany.
Jazyk:	angličtina
Zdroj:	MBio [mBio] 2024 Sep 11; Vol. 15 (9), pp. e0057824. Date of Electronic Publication: 2024 Aug 12.
DOI:	10.1128/mbio.00578-24
Abstrakt:	Lugdunin is a microbiome-derived antibacterial agent with good activity against Gram-positive pathogens in vitro and in animal models of nose colonization and skin infection. We have previously shown that lugdunin depletes bacterial energy resources by dissipating the membrane potential of Staphylococcus aureus . Here, we explored the mechanism of action of lugdunin in more detail and show that lugdunin quickly depolarizes cytoplasmic membranes of different bacterial species and acidifies the cytoplasm of S. aureus within minutes due to protonophore activity. Varying the salt species and concentrations in buffers revealed that not only protons are transported, and we demonstrate the binding of the monovalent cations K + , Na + , and Li + to lugdunin. By comparing known ionophores with various ion transport mechanisms, we conclude that the ion selectivity of lugdunin largely resembles that of 15-mer linear peptide gramicidin A. Direct interference with the main bacterial metabolic pathways including DNA, RNA, protein, and cell wall biosyntheses can be excluded. The previously observed synergism of lugdunin with dermcidin-derived peptides such as DCD-1 in killing S. aureus is mechanistically based on potentiated membrane depolarization. We also found that lugdunin was active against certain eukaryotic cells, however strongly depending on the cell line and growth conditions. While adherent lung epithelial cell lines were almost unaffected, more sensitive cells showed dissipation of the mitochondrial membrane potential. Lugdunin seems specifically adapted to its natural environment in the respiratory tract. The ionophore mechanism is refractory to resistance development and benefits from synergy with host-derived antimicrobial peptides. Importance: The vast majority of antimicrobial peptides produced by members of the microbiome target the bacterial cell envelope by many different mechanisms. These compounds and their producers have evolved side-by-side with their host and were constantly challenged by the host's immune system. These molecules are optimized to be well tolerated at their physiological site of production, and their modes of action have proven efficient in vivo . Imbalancing the cellular ion homeostasis is a prominent mechanism among antibacterial natural products. For instance, over 120 naturally occurring polyether ionophores are known to date, and antimicrobial peptides with ionophore activity have also been detected in microbiomes. In this study, we elucidated the mechanism underlying the membrane potential-dissipating activity of the thiazolidine-containing cycloheptapeptide lugdunin, the first member of the fibupeptides discovered in a commensal bacterium from the human nose, which is a promising future probiotic candidate that is not prone to resistance development. Competing Interests: The authors declare no conflict of interest.
Databáze:	MEDLINE
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