Finding effective antibiotics against multi-resistant strains of bacteria has been a challenging race. Linker-Evolved-Group-Optimized-Lipophosphonoxins (LEGO-LPPOs) are small modular synthetic antibacterial compounds targeting the cytoplasmic membrane. Here we focused on understanding the reasons for the variable efficacy of selected LEGO-LPPOs (LEGO-1, LEGO-2, LEGO-3, and LEGO-4) differing in hydrophobic and linker module structure and length. LEGO-1-4 permeabilized cytoplasmic membrane of Staphylococcus aureus, Bacillus subtilis, Pseudomonas aeruginosa, and Escherichia coli, LEGO-1 with the longest linker module being the most effective. Gram-positive bacteria were more sensitive to LEGO-LPPO action compared to Gram-negatives, which was manifested as a delayed membrane permeabilization, higher minimal inhibitory concentration and lower amount of LEGO-LPPO bound to the cells. Outer membrane permeability measurements and time-kill assay showed that presence of the intact outer membrane brought about reduced susceptibility of Gram-negatives. Using liposome leakage and in silico simulations, we showed that membranes with major content of phosphatidylethanolamine were more prone to LEGO-LPPO permeabilization. The proposed mechanism stems from an electrostatic repulsion between highly positively charged LEGO-1 molecules and positively charged amino groups of phosphatidylethanolamine which destabilizes the membrane. Collectively, these data suggest that LEGO-LPPO membrane activity is enhanced by presence of phosphatidylethanolamine but hindered by presence of intact outer membrane.

• MeSH
• antibakteriální látky * farmakologie   chemie   MeSH
• buněčná membrána metabolismus   MeSH
• Escherichia coli metabolismus   účinky léků   MeSH
• fosfatidylethanolaminy * chemie   metabolismus   MeSH
• mikrobiální testy citlivosti * MeSH
• permeabilita buněčné membrány účinky léků   MeSH
• Staphylococcus aureus účinky léků   metabolismus   MeSH
• vnější bakteriální membrána metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antibakteriální látky * MeSH
• fosfatidylethanolaminy * MeSH
• phosphatidylethanolamine MeSH Prohlížeč

In the past few decades, society has faced rapid development and spreading of antimicrobial resistance due to antibiotic misuse and overuse and the immense adaptability of bacteria. Difficulties in obtaining effective antimicrobial molecules from natural sources challenged scientists to develop synthetic molecules with antimicrobial effect. We developed modular molecules named LEGO-Lipophosphonoxins (LEGO-LPPO) capable of inducing cytoplasmic membrane perforation. In this structure-activity relationship study we focused on the role of the LEGO-LPPO hydrophobic module directing the molecule insertion into the cytoplasmic membrane. We selected three LEGO-LPPO molecules named C9, C8 and C7 differing in the length of their hydrophobic chain and consisting of an alkenyl group containing one double bond. The molecule with the long hydrophobic chain (C9) was shown to be the most effective with the lowest MIC and highest perforation rate both in vivo and in vitro. We observed high antimicrobial activity against both G+ and G- bacteria with significant differences in LEGO-LPPOs mechanism of action on these two cell types. We observed a highly cooperative mechanism of LEGO-LPPO action on G- bacteria as well as on liposomes resembling G- bacteria. LEGO-LPPO action on G- bacteria was significantly slower compared to G+ bacteria suggesting the role of the outer membrane in affecting the LEGO-LPPOs perforation rate. This notion was supported by the higher sensitivity of the E. coli strain with a compromised outer membrane. Finally, we noted that the composition of the cytoplasmic membrane affects the activity of LEGO-LPPOs since the presence of phosphatidylethanolamine increases their membrane disrupting activity.

• Publikační typ
• časopisecké články MeSH

Lipophosphonoxins (LPPOs) are small modular synthetic antibacterial compounds that target the cytoplasmic membrane. First-generation LPPOs (LPPO I) exhibit an antimicrobial activity against Gram-positive bacteria; however they do not exhibit any activity against Gram-negatives. Second-generation LPPOs (LPPO II) also exhibit broadened activity against Gram-negatives. We investigated the reasons behind this different susceptibility of bacteria to the two generations of LPPOs using model membranes and the living model bacteria Bacillus subtilis and Escherichia coli. We show that both generations of LPPOs form oligomeric conductive pores and permeabilize the bacterial membrane of sensitive cells. LPPO activity is not affected by the value of the target membrane potential, and thus they are also active against persister cells. The insensitivity of Gram-negative bacteria to LPPO I is probably caused by the barrier function of the outer membrane with LPS. LPPO I is almost incapable of overcoming the outer membrane in living cells, and the presence of LPS in liposomes substantially reduces their activity. Further, the antimicrobial activity of LPPO is also influenced by the phospholipid composition of the target membrane. A higher proportion of phospholipids with neutral charge such as phosphatidylethanolamine or phosphatidylcholine reduces the LPPO permeabilizing potential.

• MeSH
• antibakteriální látky chemická syntéza   farmakologie   MeSH
• Bacillus subtilis chemie   cytologie   účinky léků   MeSH
• Escherichia coli chemie   cytologie   účinky léků   MeSH
• fosfatidylcholiny analýza   metabolismus   MeSH
• fosfatidylethanolaminy analýza   metabolismus   MeSH
• kationické antimikrobiální peptidy chemická syntéza   farmakologie   MeSH
• lipidové dvojvrstvy MeSH
• membránové potenciály účinky léků   MeSH
• mikrobiální testy citlivosti MeSH
• permeabilita buněčné membrány MeSH
• vnější bakteriální membrána chemie   účinky léků   metabolismus   MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH
• Názvy látek
• antibakteriální látky MeSH
• fosfatidylcholiny MeSH
• fosfatidylethanolaminy MeSH
• kationické antimikrobiální peptidy MeSH
• lipidové dvojvrstvy MeSH
• phosphatidylethanolamine MeSH Prohlížeč