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Insights into the Mechanism of Action of Bactericidal Lipophosphonoxins.

Panova N, Zborníková E, Šimák O, Pohl R, Kolář M, Bogdanová K, Večeřová R, Seydlová G, Fišer R, Hadravová R, Šanderová H, Vítovská D, Šiková M, Látal T, Lovecká P, Barvík I, Krásný L, Rejman D - PLoS ONE (2015)

Bottom Line: This provides an explanation of their action in vivo where they cause serious damage of the cellular membrane, efflux of the cytosol, and cell disintegration.Finally, using one of the most potent LPPOs, we attempted and failed to select resistant strains against this compound while we were able to readily select resistant strains against a known antibiotic, rifampicin.In summary, LPPOs represent a new class of compounds with a potential for development as antibacterial agents for topical applications and perhaps also for treatment of gastrointestinal infections.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences v.v.i., Flemingovo nám. 2, 166 10 Prague 6, Czech Republic.

ABSTRACT
The advantages offered by established antibiotics in the treatment of infectious diseases are endangered due to the increase in the number of antibiotic-resistant bacterial strains. This leads to a need for new antibacterial compounds. Recently, we discovered a series of compounds termed lipophosphonoxins (LPPOs) that exhibit selective cytotoxicity towards Gram-positive bacteria that include pathogens and resistant strains. For further development of these compounds, it was necessary to identify the mechanism of their action and characterize their interaction with eukaryotic cells/organisms in more detail. Here, we show that at their bactericidal concentrations LPPOs localize to the plasmatic membrane in bacteria but not in eukaryotes. In an in vitro system we demonstrate that LPPOs create pores in the membrane. This provides an explanation of their action in vivo where they cause serious damage of the cellular membrane, efflux of the cytosol, and cell disintegration. Further, we show that (i) LPPOs are not genotoxic as determined by the Ames test, (ii) do not cross a monolayer of Caco-2 cells, suggesting they are unable of transepithelial transport, (iii) are well tolerated by living mice when administered orally but not peritoneally, and (iv) are stable at low pH, indicating they could survive the acidic environment in the stomach. Finally, using one of the most potent LPPOs, we attempted and failed to select resistant strains against this compound while we were able to readily select resistant strains against a known antibiotic, rifampicin. In summary, LPPOs represent a new class of compounds with a potential for development as antibacterial agents for topical applications and perhaps also for treatment of gastrointestinal infections.

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Related in: MedlinePlus

A model of the interaction of DR5026 with a bacterial membrane.The final state of MD simulation after 55 ns shows DR5026 molecules penetrated into the phospholipid bilayer. The nitrogen atoms from the iminosugar modules of DR5026 are highlighted as blue spheres. Phosphorus atoms of the phospholipid bilayer (PB) are depicted as yellow/red spheres. For clarity, almost all atoms of the PB are hidden.
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pone.0145918.g009: A model of the interaction of DR5026 with a bacterial membrane.The final state of MD simulation after 55 ns shows DR5026 molecules penetrated into the phospholipid bilayer. The nitrogen atoms from the iminosugar modules of DR5026 are highlighted as blue spheres. Phosphorus atoms of the phospholipid bilayer (PB) are depicted as yellow/red spheres. For clarity, almost all atoms of the PB are hidden.

Mentions: These results were in agreement with in silico molecular dynamic (MD) simulations that suggested that LPPOs may function by forming pores in the membrane by being present in both membrane layers (Fig 9; and Figure A and Figure B in S2 Supporting Information; for more details see S2 Supporting Information). In the MD simulations the high affinity of DR5026 for the model membrane seemed to arise from electrostatic interactions between the cationic iminosugar modules of LPPOs and the head groups of anionic lipids. Moreover, the hydrophobicity of lipophilic alkyl chains of LPPOs as well as the hydrophobicity of parts of uracil bases from nucleoside modules of LPPOs drove DR5026 (with the exception of their iminosugar modules) deeper into the lipid tail region of the membrane. It resulted in an amphiphilic positioning of DR5026 with the cationic iminosugar modules located at the lipid-water interface where they were anchored towards the membrane anionic head groups.


Insights into the Mechanism of Action of Bactericidal Lipophosphonoxins.

Panova N, Zborníková E, Šimák O, Pohl R, Kolář M, Bogdanová K, Večeřová R, Seydlová G, Fišer R, Hadravová R, Šanderová H, Vítovská D, Šiková M, Látal T, Lovecká P, Barvík I, Krásný L, Rejman D - PLoS ONE (2015)

A model of the interaction of DR5026 with a bacterial membrane.The final state of MD simulation after 55 ns shows DR5026 molecules penetrated into the phospholipid bilayer. The nitrogen atoms from the iminosugar modules of DR5026 are highlighted as blue spheres. Phosphorus atoms of the phospholipid bilayer (PB) are depicted as yellow/red spheres. For clarity, almost all atoms of the PB are hidden.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4696656&req=5

pone.0145918.g009: A model of the interaction of DR5026 with a bacterial membrane.The final state of MD simulation after 55 ns shows DR5026 molecules penetrated into the phospholipid bilayer. The nitrogen atoms from the iminosugar modules of DR5026 are highlighted as blue spheres. Phosphorus atoms of the phospholipid bilayer (PB) are depicted as yellow/red spheres. For clarity, almost all atoms of the PB are hidden.
Mentions: These results were in agreement with in silico molecular dynamic (MD) simulations that suggested that LPPOs may function by forming pores in the membrane by being present in both membrane layers (Fig 9; and Figure A and Figure B in S2 Supporting Information; for more details see S2 Supporting Information). In the MD simulations the high affinity of DR5026 for the model membrane seemed to arise from electrostatic interactions between the cationic iminosugar modules of LPPOs and the head groups of anionic lipids. Moreover, the hydrophobicity of lipophilic alkyl chains of LPPOs as well as the hydrophobicity of parts of uracil bases from nucleoside modules of LPPOs drove DR5026 (with the exception of their iminosugar modules) deeper into the lipid tail region of the membrane. It resulted in an amphiphilic positioning of DR5026 with the cationic iminosugar modules located at the lipid-water interface where they were anchored towards the membrane anionic head groups.

Bottom Line: This provides an explanation of their action in vivo where they cause serious damage of the cellular membrane, efflux of the cytosol, and cell disintegration.Finally, using one of the most potent LPPOs, we attempted and failed to select resistant strains against this compound while we were able to readily select resistant strains against a known antibiotic, rifampicin.In summary, LPPOs represent a new class of compounds with a potential for development as antibacterial agents for topical applications and perhaps also for treatment of gastrointestinal infections.

View Article: PubMed Central - PubMed

Affiliation: Institute of Organic Chemistry and Biochemistry, Czech Academy of Sciences v.v.i., Flemingovo nám. 2, 166 10 Prague 6, Czech Republic.

ABSTRACT
The advantages offered by established antibiotics in the treatment of infectious diseases are endangered due to the increase in the number of antibiotic-resistant bacterial strains. This leads to a need for new antibacterial compounds. Recently, we discovered a series of compounds termed lipophosphonoxins (LPPOs) that exhibit selective cytotoxicity towards Gram-positive bacteria that include pathogens and resistant strains. For further development of these compounds, it was necessary to identify the mechanism of their action and characterize their interaction with eukaryotic cells/organisms in more detail. Here, we show that at their bactericidal concentrations LPPOs localize to the plasmatic membrane in bacteria but not in eukaryotes. In an in vitro system we demonstrate that LPPOs create pores in the membrane. This provides an explanation of their action in vivo where they cause serious damage of the cellular membrane, efflux of the cytosol, and cell disintegration. Further, we show that (i) LPPOs are not genotoxic as determined by the Ames test, (ii) do not cross a monolayer of Caco-2 cells, suggesting they are unable of transepithelial transport, (iii) are well tolerated by living mice when administered orally but not peritoneally, and (iv) are stable at low pH, indicating they could survive the acidic environment in the stomach. Finally, using one of the most potent LPPOs, we attempted and failed to select resistant strains against this compound while we were able to readily select resistant strains against a known antibiotic, rifampicin. In summary, LPPOs represent a new class of compounds with a potential for development as antibacterial agents for topical applications and perhaps also for treatment of gastrointestinal infections.

Show MeSH
Related in: MedlinePlus