Peptides that form transmembrane barrel-stave pores are potential alternative therapeutics for bacterial infections and cancer. However, their optimization for clinical translation is hampered by a lack of sequence-function understanding. Recently, we have de novo designed the first synthetic barrel-stave pore-forming antimicrobial peptide with an identified function of all residues. Here, we systematically mutate the peptide to improve pore-forming ability in anticipation of enhanced activity. Using computer simulations, supported by liposome leakage and atomic force microscopy experiments, we find that pore-forming ability, while critical, is not the limiting factor for improving activity in the submicromolar range. Affinity for bacterial and cancer cell membranes needs to be optimized simultaneously. Optimized peptides more effectively killed antibiotic-resistant ESKAPEE bacteria at submicromolar concentrations, showing low cytotoxicity to human cells and skin model. Peptides showed systemic anti-infective activity in a preclinical mouse model of Acinetobacter baumannii infection. We also demonstrate peptide optimization for pH-dependent antimicrobial and anticancer activity.

• MeSH
• Acinetobacter baumannii účinky léků   MeSH
• antibakteriální látky farmakologie   chemie   chemická syntéza   MeSH
• antimikrobiální peptidy chemie   farmakologie   chemická syntéza   MeSH
• kationické antimikrobiální peptidy farmakologie   chemie   chemická syntéza   MeSH
• lidé MeSH
• mikrobiální testy citlivosti MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• protinádorové látky * farmakologie   chemie   chemická syntéza   MeSH
• racionální návrh léčiv * MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky MeSH
• antimikrobiální peptidy MeSH
• kationické antimikrobiální peptidy MeSH
• protinádorové látky * MeSH

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

Arthropod antimicrobial peptides (AMPs) offer a promising source of new leads to address the declining number of novel antibiotics and the increasing prevalence of multidrug-resistant bacterial pathogens. AMPs with potent activity against Gram-negative bacteria and distinct modes of action have been identified in insects and scorpions, allowing the discovery of AMP combinations with additive and/or synergistic effects. Here, we tested the synergistic activity of two AMPs, from the dung beetle Copris tripartitus (CopA3) and the scorpion Heterometrus petersii (Hp1090), against two strains of Escherichia coli. We also tested the antibacterial activity of two hybrid peptides generated by joining CopA3 and Hp1090 with linkers comprising two (InSco2) or six (InSco6) glycine residues. We found that CopA3 and Hp1090 acted synergistically against both bacterial strains, and the hybrid peptide InSco2 showed more potent bactericidal activity than the parental AMPs or InSco6. Molecular dynamics simulations revealed that the short linker stabilizes an N-terminal 310-helix in the hybrid peptide InSco2. This secondary structure forms from a coil region that interacts with phosphatidylethanolamine in the membrane bilayer model. The highest concentration of the hybrid peptides used in this study was associated with stronger hemolytic activity than equivalent concentrations of the parental AMPs. As observed for CopA3, the increasing concentration of InSco2 was also cytotoxic to BHK-21 cells. We conclude that AMP hybrids linked by glycine spacers display potent antibacterial activity and that the cytotoxic activity can be modulated by adjusting the nature of the linker peptide, thus offering a strategy to produce hybrid peptides as safe replacements or adjuncts for conventional antibiotic therapy.

• Klíčová slova
• Escherichia coli, antimicrobial peptide, glycine spacer, hybrid peptide, insect, scorpion,
• MeSH
• antibakteriální látky chemie   farmakologie   MeSH
• apoptóza MeSH
• Bacteria účinky léků   MeSH
• členovci chemie   MeSH
• cytotoxické proteiny tvořící póry chemie   farmakologie   MeSH
• glycin chemie   MeSH
• hemolýza účinky léků   MeSH
• křečci praví MeSH
• kultivované buňky MeSH
• ledviny účinky léků   MeSH
• myši MeSH
• zvířata MeSH
• Check Tag
• křečci praví MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky MeSH
• cytotoxické proteiny tvořící póry MeSH
• glycin MeSH

Nosocomial infections, which greatly increase morbidity among hospitalized patients, together with growing antibiotic resistance still encourage many researchers to search for novel antimicrobial compounds. Picolinium salts with different lengths of alkyl chains (C12, C14, C16) were prepared by Menshutkin-like reaction and evaluated with respect to their biological activity, i.e., lipophilicity and critical micellar concentration. Picolinium salts with C14 and C16 side chains achieved similar or even better results when in terms of antimicrobial efficacy than benzalkoniums; notably, their fungicidal efficiency was substantially more potent. The position of the methyl substituent on the aromatic ring does not seem to affect antimicrobial activity, in contrast to the effect of length of the N-alkyl chain. Concurrently, picolinium salts exhibited satisfactory low cytotoxicity against mammalian cells, i.e., lower than that of benzalkonium compounds, which are considered as safe.

• Klíčová slova
• antimicrobial activity, critical micellar concentration, cytotoxicity, picolinium salts, quaternary ammonium compounds, surfactant,
• MeSH
• antibakteriální látky farmakologie   MeSH
• antiinfekční látky farmakologie   MeSH
• antivirové látky farmakologie   MeSH
• Candida účinky léků   MeSH
• CHO buňky MeSH
• Cricetulus MeSH
• gramnegativní bakterie účinky léků   MeSH
• grampozitivní bakterie účinky léků   MeSH
• houby účinky léků   MeSH
• kvartérní amoniové sloučeniny chemie   farmakologie   MeSH
• kyseliny pikolinové chemická syntéza   chemie   farmakologie   MeSH
• mikrobiální testy citlivosti MeSH
• povrchově aktivní látky chemie   farmakologie   MeSH
• viabilita buněk účinky léků   MeSH
• virus varicella zoster účinky léků   MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky MeSH
• antiinfekční látky MeSH
• antivirové látky MeSH
• kvartérní amoniové sloučeniny MeSH
• kyseliny pikolinové MeSH
• picolinic acid MeSH Prohlížeč
• povrchově aktivní látky MeSH

Antimicrobial peptides (AMPs) are crucial effectors of the innate immune system. They provide the first line of defense against a variety of pathogens. AMPs display synergistic effects with conventional antibiotics, and thus present the potential for combined therapies. Insects are extremely resistant to bacterial infections. Insect AMPs are cationic and comprise less than 100 amino acids. These insect peptides exhibit an antimicrobial effect by disrupting the microbial membrane and do not easily allow microbes to develop drug resistance. Currently, membrane mechanisms underlying the antimicrobial effects of AMPs are proposed by different modes: the barrel-stave mode, toroidal-pore, carpet, and disordered toroidal-pore are the typical modes. Positive charge quantity, hydrophobic property and the secondary structure of the peptide are important for the antibacterial activity of AMPs. At present, several structural families of AMPs from insects are known (defensins, cecropins, drosocins, attacins, diptericins, ponericins, metchnikowins, and melittin), but new AMPs are frequently discovered. We reviewed the biological effects of the major insect AMPs. This review will provide further information that facilitates the study of insect AMPs and shed some light on novel microbicides.

• Klíčová slova
• AMP *, Structure-activity relationship *, antimicrobial peptides *, mechanism of action *, modification *,
• MeSH
• antiinfekční látky chemie   terapeutické užití   MeSH
• bakteriální infekce farmakoterapie   MeSH
• hmyz chemie   MeSH
• sekvence aminokyselin MeSH
• zvířata MeSH
• Check Tag
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• přehledy MeSH
• Názvy látek
• antiinfekční látky MeSH

We examined the benefits of short linear α-helical antimicrobial peptides (AMPs) invented in our laboratory for treating bone infection and preventing microbial biofilm formation on model implants due to causative microorganisms of osteomyelitis. For this purpose, we introduced a model of induced osteomyelitis that utilizes human femur heads obtained from the hospital after their replacement with artificial prostheses. We found that the focus of the infection set up in the spongy part of this bone treated with AMP-loaded calcium phosphate cement was eradicated much more effectively than was the focus treated with antibiotics such as vancomycin or gentamicin loaded into the same cement. This contradicts the minimum inhibitory concentrations (MIC) values of AMPs and antibiotics against some bacterial strains obtained in standard in vitro assays. The formation of microbial biofilm on implants made from poly(methylmethacrylate)-based bone cement loaded with AMP was evaluated after the implants' removal from the infected bone sample. AMPs loaded in such model implants prevented microbial adhesion and subsequent formation of bacterial biofilm on their surface. Biofilms did form, on the other hand, on control implants made from the plain cement when these were implanted into the same infected bone sample. These results of the experiments performed in human bone tissue highlight the clinical potential of antimicrobial peptides for use in treating and preventing osteomyelitis caused by resistant pathogens.

• Klíčová slova
• antimicrobial peptides, bone cement, femur heads, implant-related infections, osteomyelitis,
• Publikační typ
• časopisecké články MeSH

Joint replacement infections and osteomyelitis are among the most serious complications in orthopaedics and traumatology. The risk factors for these infections are often bacterial resistance to antimicrobials. One of the few solutions available to control bacterial resistance involves antimicrobials, which have a different mechanism of action from traditional antibiotics. Antimicrobial peptides (AMP) appear to be highly promising candidates in the treatment of resistant infections. We have identified several AMP in the venom of various wild bees and designed analogues that show potent antimicrobial activity and low toxicity against eukaryotic cells. The aim of the present study was to test the efficacy of one of those synthetic peptide analogues for the treatment of acute osteomyelitis invoked in laboratory rats. Femoral cavities of 20 laboratory Wistar rats were infected with Staphylococcus aureus. After 1 week, eight rats received an injectable calcium phosphate carrier alone, another eight rats were treated with a calcium phosphate mixed with AMP, and four rats were left without any further treatment. After another week, all rats were euthanized and radiographs were made of both the operated and healthy limbs. The animals with the carrier alone exhibited more severe acute osteomyelitis on radiographs in comparison to the recipients of the calcium phosphate carrier loaded AMP and untreated infected individuals. Based on the results of the above mentioned experiment, it was concluded that when injected directly into the site of femoral acute osteomyelitis, the calcium phosphate carrier mixed with AMP reduced osteomyelitis signs visible on radiographs.

• MeSH
• antibakteriální látky aplikace a dávkování   MeSH
• fosforečnany vápenaté farmakologie   MeSH
• krysa rodu Rattus MeSH
• lidé MeSH
• osteomyelitida farmakoterapie   mikrobiologie   MeSH
• peptidy aplikace a dávkování   MeSH
• potkani Wistar MeSH
• stafylokokové infekce farmakoterapie   mikrobiologie   MeSH
• Staphylococcus aureus účinky léků   fyziologie   MeSH
• zvířata MeSH
• Check Tag
• krysa rodu Rattus MeSH
• lidé MeSH
• mužské pohlaví MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• antibakteriální látky MeSH
• calcium phosphate MeSH Prohlížeč
• fosforečnany vápenaté MeSH
• peptidy MeSH

Defensins are the most widespread antimicrobial peptides characterised in insects. These cyclic peptides, 4-6 kDa in size, are folded into α-helical/β-sheet mixed structures and have a common conserved motif of three intramolecular disulfide bridges with a Cys1-Cys4, Cys2-Cys5 and Cys3-Cys6 connectivity. They have the ability to kill especially Gram-positive bacteria and some fungi, but Gram-negative bacteria are more resistant against them. Among them are the medicinally important compounds lucifensin and lucifensin II, which have recently been identified in the medicinal larvae of the blowflies Lucilia sericata and Lucilia cuprina, respectively. These defensins contribute to wound healing during a procedure known as maggot debridement therapy (MDT) which is routinely used at hospitals worldwide. Here we discuss the decades-long story of the effort to isolate and characterise these two defensins from the bodies of medicinal larvae or from their secretions/excretions. Furthermore, our previous studies showed that the free-range larvae of L. sericata acutely eliminated most of the Gram-positive strains of bacteria and some Gram-negative strains in patients with infected diabetic foot ulcers, but MDT was ineffective during the healing of wounds infected with Pseudomonas sp. and Acinetobacter sp. The bactericidal role of lucifensins secreted into the infected wound by larvae during MDT and its ability to enhance host immunity by functioning as immunomodulator is also discussed.

• Publikační typ
• časopisecké články MeSH