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1.
World J Microbiol Biotechnol ; 36(1): 18, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31912374

RESUMO

In this paper, we report the antimicrobial activity of AMEP412 (a protein elicitor from Bacillus subtilis) against Streptomyces scabiei, which is the potato common scab pathogen. The purified protein samples showed an obvious inhibition zone on an S. scabiei agar plate, and the minimum inhibition concentration detected was 50 µg mL-1. The fluorescence localization assay revealed that AMEP412 could bind to aerial mycelia and spores. The stability test showed that AMEP412 was stable at 60 °C for 30 min and in pH values from 5.0 to 10.0. Its antimicrobial activity was not sensitive to metal cations. However, its activity declined by 23% when treated with Proteinase K, and was completely abrogated with Tween 80 treatment. Three antimicrobial peptides (GS21, GY20 and GY23) were identified from AMEP412, which further verified its antimicrobial activity. This research reveals the antimicrobial function of AMEP412, which not only enriches the function of the protein elicitor, but also provides a candidate for the biocontrol of potato common scab.


Assuntos
Antibacterianos/farmacologia , Bacillus subtilis/metabolismo , Proteínas de Bactérias/farmacologia , Streptomyces/efeitos dos fármacos , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Proteínas de Bactérias/química , Temperatura Alta , Concentração de Íons de Hidrogênio , Testes de Sensibilidade Microbiana , Micélio/efeitos dos fármacos , Doenças das Plantas/prevenção & controle , Solanum tuberosum/microbiologia , Esporos Bacterianos/efeitos dos fármacos , Streptomyces/crescimento & desenvolvimento
2.
Chem Biol Interact ; 315: 108904, 2020 Jan 05.
Artigo em Inglês | MEDLINE | ID: mdl-31758921

RESUMO

Epinecidin-1 (epi) was identified from orange-spotted grouper (Epinephelus coioides) and exhibits diverse biological activities. The aims of this study were to investigate how the distribution of positively charged amino acid residues affects epi-mediated cytotoxicity and to examine the molecular mechanism underlying epi-induced cytotoxicity in U87MG human glioblastoma cells. MTS/PMS and trypan blue exclusion assay were used to measure cell viability. Necrotic cell death was confirmed by detecting cyclophilin A release and propidium iodide incorporation. DNA damage was evaluated by measuring phosphorylated H2AX. Intracellular reactive oxygen species (ROS) were analyzed by flow cytometry using dihydroergotamine. Mitochondrial membrane potential was detected by flow cytometry using tetramethylrhodamine, ethyl ester. Overall, we found that epi caused cytotoxicity in U87MG cells by inducing DNA damage and necrosis through mitochondrial hyperpolarization and subsequent ROS production. The proper folding of epi into an α-helical structure was essential for epi-mediated anti-glioblastoma effects. In addition, NFκB signaling was activated in U87MG cells after exposure to epi. Suppression of NFκB further enhanced epi-induced cytotoxicity, ROS generation and DNA damage, indicating that NFκB may play a protective role in epi-induced cytotoxicity. Our findings may be useful for the design and improvement of antimicrobial peptides with anti-cancer activity.


Assuntos
Aminoácidos/metabolismo , Peptídeos Catiônicos Antimicrobianos/metabolismo , Peptídeos Catiônicos Antimicrobianos/farmacologia , Apoptose/efeitos dos fármacos , Proteínas de Peixes/metabolismo , Proteínas de Peixes/farmacologia , Glioblastoma/tratamento farmacológico , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Dano ao DNA/efeitos dos fármacos , Glioblastoma/metabolismo , Humanos , Potencial da Membrana Mitocondrial/efeitos dos fármacos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , NF-kappa B/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos
3.
Protein Pept Lett ; 27(1): 41-47, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31438823

RESUMO

BACKGROUND: Thanatin is the smallest member of Beta-hairpin class of cationic peptide derived from insects with vast activities against various pathogens. OBJECTIVE: In this study, the antimicrobial activity of this peptide against some species of human bacterial pathogens as well as its toxicity on NIH cells were evaluated. METHODS: Thanatin DNA sequence was cloned into pcDNA3.1+ vector and transformed into a DH5α bacterial strain. Then the recombinant plasmids were transfected into HEK-293 cells by calcium phosphate co-precipitation. After applying antibiotic treatment, the supernatant medium containing thanatin was collected. The peptide quantity was estimated by SDS-PAGE and GelQuant software. The antimicrobial activity of this peptide was performed with Minimum Inhibitory Concentration (MIC) method. In addition, its toxicity on NIH cells were evaluated by MTT assay. RESULTS: The peptide quantity was estimated approximately 164.21 µmolL-1. The antibacterial activity of thanatin was estimated between 0.99 and 31.58 µmolL-1 using MIC method. The result of cytotoxicity test on NIH cell line showed that the peptide toxicity up to the concentration of 394.10 µmolL-1 and for 48 hours, was not statistically significant from negative control cells (P>0.05). The antimicrobial assay demonstrated that thanatin had an antibacterial effect on some tested microorganisms. The results obtained in this study also showed that thanatin had no toxicity on mammalian cell lines including HEK293 and NIH. CONCLUSION: Antimicrobial peptides such as thanatin are considered to be appropriate alternatives to conventional antibiotics in treating various human pathological diseases bacteria.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Proteínas Recombinantes/farmacologia , Animais , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/genética , Sequência de Bases , Fosfatos de Cálcio/química , Sobrevivência Celular , Expressão Gênica , Células HEK293 , Humanos , Camundongos , Testes de Sensibilidade Microbiana , Células NIH 3T3 , Proteínas Recombinantes/química , Proteínas Recombinantes/genética , Transfecção
4.
Protein Pept Lett ; 27(1): 4-16, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-31438824

RESUMO

Antimicrobial peptides in recent years have gained increased interest among scientists, health professionals and the pharmaceutical companies owing to their therapeutic potential. These are low molecular weight proteins with broad range antimicrobial and immuno modulatory activities against infectious bacteria (Gram positive and Gram negative), viruses and fungi. Inability of micro-organisms to develop resistance against most of the antimicrobial peptide has made them as an efficient product which can greatly impact the new era of antimicrobials. In addition to this these peptides also demonstrates increased efficacy, high specificity, decreased drug interaction, low toxicity, biological diversity and direct attacking properties. Pharmaceutical industries are therefore conducting appropriate clinical trials to develop these peptides as potential therapeutic drugs. More than 60 peptide drugs have already reached the market and several hundreds of novel therapeutic peptides are in preclinical and clinical development. Rational designing can be used further to modify the chemical and physical properties of existing peptides. This mini review will discuss the sources, mechanism and recent therapeutic applications of antimicrobial peptides in treatment of infectious diseases.


Assuntos
Anti-Infecciosos/química , Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias/efeitos dos fármacos , Interações de Medicamentos , Resistência Microbiana a Medicamentos , Fungos/efeitos dos fármacos , Humanos , Testes de Sensibilidade Microbiana , Peso Molecular , Resultado do Tratamento , Vírus/efeitos dos fármacos
5.
Exp Parasitol ; 209: 107823, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31862270

RESUMO

Typically, antimicrobial peptides (AMPs) are short positive charged peptides serving a key role in innate immunity as well as antimicrobial activity. Discovering novel therapeutic agents is considered as an undeniable demand due to increasing microbial species with antibiotic resistance. In this direction, the unique ability of AMPs to modulate immune responses highlighted them as novel drug candidates in the field of microbiology. Patients affected by leishmaniasis; a neglected tropical disease, confront serious problems for their treatment including resistance to common drugs as well as toxicity and high cost of therapy. So, there is a need for development of new drug candidates to control the diseases. Jellein, a peptide derived from royal jelly of honeybee has been shown to have promising effect against several bacterial and fungal species. In current study, anti-leishmanial effect of Jellein and its lauric acid conjugated form was investigated against two forms of Leishmania major (L. major) parasite. Moreover, cytotoxic effect of these peptides was studied in THP1 cell line and human Red Blood Cells (RBCs). Furthermore, the mechanism of action of peptides on L. major promastigotes was assessed through different methods. The results demonstrated that, conjugation of lauric acid to Jellein not only had no effect on the elevation of antimicrobial activity but also halted it completely. Moreover, Jellein caused a limitation in the number of L. major promastigotes by pore formation as well as changing the membrane potential rather than induction of apoptosis or activation of caspases.


Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Antiprotozoários/farmacologia , Leishmania major/efeitos dos fármacos , Leishmaniose Cutânea/tratamento farmacológico , Oligopeptídeos/química , Antígenos de Diferenciação de Linfócitos B/farmacologia , Peptídeos Catiônicos Antimicrobianos/uso terapêutico , Peptídeos Catiônicos Antimicrobianos/toxicidade , Antiprotozoários/uso terapêutico , Antiprotozoários/toxicidade , Caspases/efeitos dos fármacos , Caspases/metabolismo , Linhagem Celular Tumoral , Permeabilidade da Membrana Celular/efeitos dos fármacos , Eritrócitos/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Ácidos Graxos/química , Citometria de Fluxo , Hemólise , Antígenos de Histocompatibilidade Classe II/farmacologia , Humanos , Ácidos Láuricos/farmacologia , Ácidos Láuricos/uso terapêutico , Ácidos Láuricos/toxicidade , Leishmania major/ultraestrutura , Potenciais da Membrana/efeitos dos fármacos , Microscopia Eletrônica de Varredura , Doenças Negligenciadas/tratamento farmacológico , Doenças Negligenciadas/parasitologia , Oligopeptídeos/farmacologia , Oligopeptídeos/uso terapêutico , Oligopeptídeos/toxicidade
6.
Biosci Biotechnol Biochem ; 84(1): 143-153, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31549575

RESUMO

Brevinin-GR23 (B-GR23) was a brevinin-2 like antimicrobial peptide, which had antimicrobial activity against Staphylococcus aureus with minimum inhibitory concentration (MIC) of 16 µM. B-GR23 increased the bacterial membrane permeation, leading to the damage of membrane integrity and the leakage of genomic DNA, then causing the cell death. The peptide nearly inhibited all plantonic bacteria to start the initial attachment of biofilm at the concentration of 1 × MIC. Whereas the disruption rates on immature and mature biofilm decreased from 60% to 20%. B-GR23 reduced the production of extracellular polysaccharides (EPS) in the planktonic growth of S. aureus, which is a crucial structure of biofilm formation. B-GR23 with the concentration of ½ × MIC inhibited 50% water-soluble EPS, and 48% water-insoluble EPS, which contributed to the antibiofilm activity. B-GR23 had no significant toxicity to human blood cells under-tested concentration (200 µM), making it a potential template for designing antimicrobial peptides.


Assuntos
Proteínas de Anfíbios/farmacologia , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Biofilmes/efeitos dos fármacos , Staphylococcus aureus/fisiologia , Animais , Antibacterianos/síntese química , Peptídeos Catiônicos Antimicrobianos/síntese química , Peptídeos Catiônicos Antimicrobianos/química , Permeabilidade da Membrana Celular/efeitos dos fármacos , DNA Bacteriano/efeitos dos fármacos , DNA Bacteriano/metabolismo , Eritrócitos/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Temperatura Alta , Humanos , Concentração de Íons de Hidrogênio , Testes de Sensibilidade Microbiana/métodos , Polissacarídeos Bacterianos/antagonistas & inibidores , Conformação Proteica em alfa-Hélice , Estabilidade Proteica/efeitos da radiação , Ranidae , Infecções Estafilocócicas/tratamento farmacológico
7.
Arch Insect Biochem Physiol ; 103(1): e21626, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31562754

RESUMO

Insects can produce various antimicrobial peptides (AMPs) upon immune stimulation. One class of AMPs are characterized by their high proline content in certain fragments. They are generally called proline-rich antimicrobial peptides (PrAMPs). We previously reported the characterization of Spodoptera litura lebocin-1 (SlLeb-1), a PrAMP proprotein. Preliminary studies with synthetic polypeptides showed that among the four deductive active fragments, the C-terminal fragment SlLeb-1 (124-158) showed strong antibacterial activities. Here, we further characterized the antibacterial and antifungal activities of 124-158 and its four subfragments: 124-155, 124-149, 127-158, and 135-158. Only 124-158 and 127-158 could agglutinate bacteria, while 124-158 and four subfragments all could agglutinate Beauveria bassiana spores. Confocal microscopy showed that fluorescent peptides were located on the microbial surface. Fragment 135-158 lost activity completely against Escherichia coli and Staphylococcus aureus, and partially against Bacillus subtilis. Only 124-149 showed low activity against Serratia marcescens. Negative staining, transmission, and scanning electron microscopy of 124-158 treated bacteria showed different morphologies. Flow cytometry analysis of S. aureus showed that 124-158 and four subfragments changed bacterial subpopulations and caused an increase of DNA content. These results indicate that active fragments of SlLeb-1 may have diverse antimicrobial effects against different microbes. This study may provide an insight into the development of novel antimicrobial agents.


Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Proteínas de Insetos/farmacologia , Spodoptera/química , Animais , Peptídeos Catiônicos Antimicrobianos/química , Bacillus subtilis/efeitos dos fármacos , Beauveria/efeitos dos fármacos , Escherichia coli/efeitos dos fármacos , Proteínas de Insetos/química , Serratia marcescens/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos
8.
Eur J Med Chem ; 185: 111814, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31678742

RESUMO

The emergence of multidrug-resistant (MDR) Pseudomonas aeruginosa, coupled with shrinking antibiotic pipelines, has increased the demand for new antimicrobials with novel mechanisms of action. As the indiscriminate nature of broad-spectrum antimicrobial toxicity may have negative clinical consequences and increase the incidence of resistance, we have developed a P. aeruginosa-selective antimicrobial peptide capable of preferentially killing P. aeruginosa relative to benign microorganisms. A targeting peptide (PA2) that binds specifically to OprF porin on P. aeruginosa was identified by phage display peptide library screening, and a hybrid peptide was constructed by addition of the targeting peptide to GNU7, a potent antimicrobial peptide. The resulting hybrid peptide PA2-GNU7 exhibited potent antimicrobial activity against P. aeruginosa without causing host toxicity. Confocal laser scanning microscopy analysis and time-kill experiments demonstrated that PA2-GNU7 exhibited a high degree of specificity for P. aeruginosa, and rapidly and selectively killed P. aeruginosa cells in mixed cultures. In addition, in vivo treatment efficacy of PA2-GNU7 was significantly greater than that of conventional antibiotics in a mouse model of MDR P. aeruginosa infection. Taken together, the data suggest that PA2-GNU7 may be a promising template for further development as a novel anti-MDR P. aeruginosa therapeutic agent.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Infecções por Pseudomonas/tratamento farmacológico , Pseudomonas aeruginosa/efeitos dos fármacos , Animais , Antibacterianos/síntese química , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/síntese química , Peptídeos Catiônicos Antimicrobianos/química , Relação Dose-Resposta a Droga , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Testes de Sensibilidade Microbiana , Pseudomonas aeruginosa/citologia , Relação Estrutura-Atividade
9.
Int J Nanomedicine ; 14: 9777-9792, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31849468

RESUMO

Purpose: Staphylococcus aureus is the most common persistent pathogen in humans, so development of new formulations to combat pathogen invasion is quite necessary. Methods: In the current study, for the first time, the synergistic activity of recombinant lysostaphin and LL-37 peptide was studied against S. aureus. Moreover, different niosomal formulations of the peptide and protein were prepared and analyzed in terms of size, shape, zeta potential, and entrapment efficiency. Also, a long-term antibacterial activity of the best niosomal formulation and free forms was measured against S. aureus in vitro. Results: The optimal niosomal formulation was obtained by mixing the surfactants (span60 and tween60; 2:1 w/w), cholesterol, and dicetylphosphate at a ratio of 47:47:6, respectively. They showed uniform spherical shapes with the size of 565 and 325 nm for lysostaphin and LL-37, respectively. This formulation showed high entrapment efficiency for the peptide, protein, and a slow-release profile over time. Release kinetic was best fitted by Higuchi model indicating a diffusion-based release of the drugs. The lysostaphin/LL-37 niosomal formulation synergistically inhibited growth of S. aureus for up to 72 hours. However, the same amounts of free forms of both anti-microbial agents could not hold the anti-microbial effect and growth was seen in the following 72 hours. Cytotoxicity assay specified that lysostaphin/LL-37 niosomal combination had no deleterious effect on normal fibroblast cells at effective antimicrobial concentrations. Conclusion: This study indicated that the use of lysostaphin in combination with LL-37, either in niosomal or free forms, synergistically inhibited growth of S. aureus in vitro. In addition, niosomal preparation of antimicrobial agents could provide a long-term protection against bacterial infections.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Lisostafina/farmacologia , Staphylococcus aureus/efeitos dos fármacos , Animais , Antibacterianos/farmacocinética , Peptídeos Catiônicos Antimicrobianos/farmacocinética , Liberação Controlada de Fármacos , Sinergismo Farmacológico , Fibroblastos/efeitos dos fármacos , Lipossomos/química , Lipossomos/farmacologia , Lisostafina/genética , Lisostafina/farmacocinética , Camundongos , Testes de Sensibilidade Microbiana , Tamanho da Partícula , Proteínas Recombinantes/genética , Proteínas Recombinantes/farmacologia , Infecções Estafilocócicas/tratamento farmacológico
10.
J Photochem Photobiol B ; 200: 111645, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31671371

RESUMO

Antimicrobial peptide W3R6 was derived from chensinin-1b and showed potential as a novel antibiotics. However, W3R6 was susceptible to protease cleavage, which limited its therapeutic application. To improve the proteolytic resistance of W3R6, D-amino acids were incorporated into its sequence by specific amino acid substitution or whole sequence substitution according to the specificity of the cleavage site. In this study, partially substituted analog D-Arg-W3R6 and completely substituted D-enantiomer D-W3R6 were synthesized. The resistance of D-Arg-W3R6 and D-W3R6 to cleavage by the tested protease increased, particularly of D-W3R6. The antimicrobial activity of D-Arg-W3R6 was almost the same as that of the parent peptide W3R6, but the antimicrobial activity of D-W3R6 was slightly decreased. The hemolytic activity of both D-Arg-W3R6 and D-W3R6 was negligible. The CD spectrum of D-W3R6 exhibited symmetry with that of W3R6 in a membrane-mimetic environment. The membrane interaction between the D-amino acid substituted analogs and a real/mimic bacterial cell membrane was examined. The outer membrane depolarization, inner membrane permeability and dye leakage in three types of liposomes treated with D-Arg-W3R6 and D-W3R6 were not obviously different from W3R6, which could be due to the similar physical and chemical properties. In addition, these three peptides showed the binding ability with LPS micelles detected by ITC, and their ability to disrupt the LPS micelles was examined by DLS experiment and even neutralize the surface negative charge of E. coli cells. These results suggest that D-Arg-W3R6 is a promising antibiotic molecule.


Assuntos
Aminoácidos/química , Anti-Infecciosos/química , Peptídeos Catiônicos Antimicrobianos/química , Anti-Infecciosos/síntese química , Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/síntese química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Parede Celular/química , Parede Celular/efeitos dos fármacos , Parede Celular/metabolismo , Eritrócitos/citologia , Eritrócitos/efeitos dos fármacos , Eritrócitos/metabolismo , Bactérias Gram-Negativas/efeitos dos fármacos , Bactérias Gram-Positivas/efeitos dos fármacos , Hemólise/efeitos dos fármacos , Humanos , Lipossomos/química , Lipossomos/metabolismo , Peptídeos/química , Permeabilidade/efeitos dos fármacos , Estabilidade Proteica
11.
Analyst ; 144(24): 7242-7249, 2019 Dec 21.
Artigo em Inglês | MEDLINE | ID: mdl-31687669

RESUMO

Rapid detection and identification of bacteria is important for human health, biodefense, and food safety. Small arrays of different antimicrobial peptides (AMPs) enable the identification of lipopolysaccharide (LPS) samples from a variety of bacterial species and strains. A model system for examining how peptide presentation affects LPS detection is the sheep myeloid antimicrobial peptide (SMAP-29), which contains a helix-turn-helix motif. Varying the cysteine attachment site on SMAP-29 controls the three-dimensional presentation of the peptide on the surface, altering the ability of the peptide to discriminate between LPS samples. A small array of only SMAP-29 variants-and no other peptides-is capable of discriminating among LPS samples from multiple bacterial species, as well as between different strains within the same species, with high accuracy.


Assuntos
Peptídeos Catiônicos Antimicrobianos/química , Proteínas Sanguíneas/química , Catelicidinas/química , Lipopolissacarídeos/química , Animais , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias/metabolismo , Sítios de Ligação , Cisteína/química , Humanos , Lipopolissacarídeos/antagonistas & inibidores , Ovinos , Especificidade da Espécie , Ressonância de Plasmônio de Superfície
12.
Int J Mol Sci ; 20(19)2019 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-31581426

RESUMO

The advent of multidrug resistance among pathogenic bacteria has attracted great attention worldwide. As a response to this growing challenge, diverse studies have focused on the development of novel anti-infective therapies, including antimicrobial peptides (AMPs). The biological properties of this class of antimicrobials have been thoroughly investigated, and membranolytic activities are the most reported mechanisms by which AMPs kill bacteria. Nevertheless, an increasing number of works have pointed to a different direction, in which AMPs are seen to be capable of displaying non-lytic modes of action by internalizing bacterial cells. In this context, this review focused on the description of the in vitro and in vivo antibacterial and antibiofilm activities of non-lytic AMPs, including indolicidin, buforin II PR-39, bactenecins, apidaecin, and drosocin, also shedding light on how AMPs interact with and further translocate through bacterial membranes to act on intracellular targets, including DNA, RNA, cell wall and protein synthesis.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias/efeitos dos fármacos , Membrana Celular/efeitos dos fármacos , Membrana Celular/metabolismo , Animais , Peptídeos Catiônicos Antimicrobianos/metabolismo , Bactérias/metabolismo , Glicopeptídeos/metabolismo , Insetos , Biossíntese de Proteínas
13.
Int J Mol Sci ; 20(19)2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31581682

RESUMO

Recently, bioactive peptides have attracted attention for their therapeutic applications in the pharmaceutical industry. Among them, antimicrobial peptides are candidates for new antibiotic drugs. Since pseudin-2 (Ps), isolated from the skin of the paradoxical frog Pseudis paradoxa, shows broad-spectrum antibacterial activity with high cytotoxicity, we previously designed Ps-K18 with a Lys substitution for Leu18 in Ps, which showed high antibacterial activity and low toxicity. Here, we examined the potency of Ps-K18, aiming to develop antibiotics derived from bioactive peptides for the treatment of Gram-negative sepsis. We first investigated the antibacterial mechanism of Ps-K18 based on confocal micrographs and field emission scanning electron microscopy, confirming that Ps-K18 targets the bacterial membrane. Anti-inflammatory mechanism of Ps-K18 was investigated by secreted alkaline phosphatase reporter gene assays and RT-PCR, which revealed that Ps-K18 activates innate defense via Toll-like receptor 4-mediated nuclear factor-kappa B signaling pathways. Moreover, we investigated the antiseptic effect of Ps-K18 using a lipopolysaccharide or Escherichia coli K1-induced septic shock mouse model. Ps-K18 significantly reduced bacterial growth and inflammatory responses in the septic shock model. Ps-K18 showed low renal and liver toxicity and attenuated lung damage effectively. This study suggests that Ps-K18 is a potent peptide antibiotic that could be applied therapeutically to Gram-negative sepsis.


Assuntos
Proteínas de Anfíbios/química , Anti-Infecciosos Locais/farmacologia , Anti-Inflamatórios/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Animais , Peptídeos Catiônicos Antimicrobianos/química , Sobrevivência Celular/efeitos dos fármacos , Modelos Animais de Doenças , Endotoxemia/tratamento farmacológico , Endotoxemia/microbiologia , Escherichia coli/efeitos dos fármacos , Escherichia coli/ultraestrutura , Humanos , Macrófagos , Camundongos , Receptor 4 Toll-Like/genética , Receptor 4 Toll-Like/metabolismo
14.
J Immunol Res ; 2019: 3979352, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31583256

RESUMO

Methicillin-resistant Staphylococcus aureus (MRSA) is the major pathogen responsible for community and hospital bacterial infections. Sublancin, a glucosylated antimicrobial peptide isolated from Bacillus subtilis 168, possesses antibacterial infective effects. In this study, we investigated the role and anti-infection mechanism of sublancin in a mouse model of MRSA-induced sublethal infection. Sublancin could modulate innate immunity by inducing the production of IL-1ß, IL-6, TNF-α, and nitric oxide, enhancing phagocytosis and MRSA-killing activity in both RAW264.7 cells and mouse peritoneal macrophages. The enhanced macrophage function by the peptide in vitro correlated with stronger protective activity in vivo in the MRSA-invasive sublethal infection model. Macrophage activation by sublancin was found to be partly dependent on TLR4 and the NF-κB and MAPK signaling pathways. Moreover, oral administration of sublancin increased the frequencies of CD4+ and CD8+ T cells in mesenteric lymph nodes. The protective activity of sublancin was associated with in vivo augmenting phagocytic activity of peritoneal macrophages and partly improving T cell-mediated immunity. Macrophages thus represent a potentially pivotal and novel target for future development of innate defense regulator therapeutics against S. aureus infection.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Macrófagos/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Infecções Estafilocócicas/microbiologia , Animais , Biomarcadores , Citocinas/metabolismo , Feminino , Macrófagos/imunologia , Staphylococcus aureus Resistente à Meticilina/imunologia , Camundongos , Óxido Nítrico/metabolismo , Células RAW 264.7 , Transdução de Sinais , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/imunologia
15.
Nat Commun ; 10(1): 4538, 2019 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-31586049

RESUMO

Antimicrobial peptides (AMPs) are promising antimicrobials, however, the potential of bacterial resistance is a major concern. Here we systematically study the evolution of resistance to 14 chemically diverse AMPs and 12 antibiotics in Escherichia coli. Our work indicates that evolution of resistance against certain AMPs, such as tachyplesin II and cecropin P1, is limited. Resistance level provided by point mutations and gene amplification is very low and antibiotic-resistant bacteria display no cross-resistance to these AMPs. Moreover, genomic fragments derived from a wide range of soil bacteria confer no detectable resistance against these AMPs when introduced into native host bacteria on plasmids. We have found that simple physicochemical features dictate bacterial propensity to evolve resistance against AMPs. Our work could serve as a promising source for the development of new AMP-based therapeutics less prone to resistance, a feature necessary to avoid any possible interference with our innate immune system.


Assuntos
Anti-Infecciosos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Farmacorresistência Bacteriana Múltipla/genética , Genoma Bacteriano/efeitos dos fármacos , Peptídeos Catiônicos Antimicrobianos/uso terapêutico , Bactérias/efeitos dos fármacos , Bactérias/genética , Infecções Bacterianas/tratamento farmacológico , Evolução Molecular Direcionada , Desenvolvimento de Medicamentos/métodos , Farmacorresistência Bacteriana Múltipla/efeitos dos fármacos , Genoma Bacteriano/genética , Humanos , Metagenômica , Testes de Sensibilidade Microbiana , Plasmídeos/genética , Mutação Puntual , Microbiologia do Solo
16.
Zool Res ; 40(6): 488-505, 2019 Nov 18.
Artigo em Inglês | MEDLINE | ID: mdl-31592585

RESUMO

The discovery of antibiotics marked a golden age in the revolution of human medicine. However, decades later, bacterial infections remain a global healthcare threat, and a return to the pre-antibiotic era seems inevitable if stringent measures are not adopted to curb the rapid emergence and spread of multidrug resistance and the indiscriminate use of antibiotics. In hospital settings, multidrug resistant (MDR) pathogens, including carbapenem-resistant Pseudomonas aeruginosa, vancomycin-resistant enterococci (VRE), methicillin-resistant Staphylococcus aureus (MRSA), and extended-spectrum ß-lactamases (ESBL) bearing Acinetobacter baumannii, Escherichia coli, and Klebsiella pneumoniae are amongst the most problematic due to the paucity of treatment options, increased hospital stay, and exorbitant medical costs. Antimicrobial peptides (AMPs) provide an excellent potential strategy for combating these threats. Compared to empirical antibiotics, they show low tendency to select for resistance, rapid killing action, broad-spectrum activity, and extraordinary clinical efficacy against several MDR strains. Therefore, this review highlights multidrug resistance among nosocomial bacterial pathogens and its implications and reiterates the importance of AMPs as next-generation antibiotics for combating MDR superbugs.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias/efeitos dos fármacos , Farmacorresistência Bacteriana Múltipla , Animais , Peptídeos Catiônicos Antimicrobianos/química , Infecção Hospitalar/tratamento farmacológico , Infecção Hospitalar/microbiologia , Humanos
17.
Biofouling ; 35(8): 900-921, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31617758

RESUMO

Antimicrobial peptides (AMPs) are short, positively charged host defense peptides, found in various life forms from microorganisms to humans. AMPs are gaining more attention as substitutes for antibiotics in order to combat the risk posed by multi-drug- resistant pathogens. The nematode Caenorhabditis elegans relies solely on its innate immune defense to cope with its challenging life-style. Bacterial infection in C. elegans leads to induction of antimicrobial proteins, defensins, nemapores, cecropins, and neuropeptide-like proteins, which act to limit bacterial proliferation. This study reports how the C. elegans recombinant antibacterial factor (ABF-1) rapidly inhibited bacterial growth (Salmonella Typhi, Klebsiella pneumonia, Shigella sonnei and Vibrio alginolyticus). The ABF-1 exposure on S. Typhi, showed differential regulation in cell-cycle, DNA repair mechanism, membrane stability, and stress related proteins. The exogenous supply of ABF-1 protein has extended C. elegans survival by reducing the bacterial colony forming units on the nematode intestine. Together, these findings indicate the valuable and potential therapeutic applications of ABF-1 protein as antimicrobial agents against intracellular pathogens.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Fatores de Transcrição Hélice-Alça-Hélice Básicos/farmacologia , Proteínas de Caenorhabditis elegans/farmacologia , Caenorhabditis elegans , Proteínas Recombinantes/farmacologia , Salmonella typhi/efeitos dos fármacos , Animais , Peptídeos Catiônicos Antimicrobianos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Caenorhabditis elegans/microbiologia , Proteínas de Caenorhabditis elegans/genética , Humanos , Intestinos/microbiologia , Testes de Sensibilidade Microbiana , Proteínas Recombinantes/genética , Análise de Sobrevida
18.
Biochimie ; 167: 198-206, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31639404

RESUMO

The study investigates conformational analysis and the in vitro cytokine-mediated immunomodulatory and insulin-releasing activities of rhinophrynin-27 (ELRLPEIARPVPEVLPARLPLPALPRN; RP-27), a proline-arginine-rich peptide first isolated from skin secretions of the Mexican burrowing toad Rhinophrynus dorsalis (Rhinophrynidae). In both water and 50% trifluoroethanol-water, the peptide adopts a polyproline type II helical conformation with a high degree of deviation from the canonical collagen-like folding and a pronounced bend in the molecule at the Glu13 residue. Incubation of mouse peritoneal cells with RP-27 significantly (P < 0.05) inhibited production of the pro-inflammatory cytokines TNF-α and IL-1ß and stimulated production of the anti-inflammatory cytokine IL-10. The peptide significantly (P < 0.01) stimulated release of insulin from BRIN-BD11 rat clonal ß-cells at concentrations ≥ 1 nM while maintaining the integrity of the plasma membrane and also stimulated insulin release from isolated mouse islets at a concentration of 10-6 M. Increasing the cationicity of RP-27 by substituting glutamic acid residues in the peptide by arginine and increasing hydrophobicity by substituting alanine residues by tryptophan did not result in analogues with increased activity with respect to cytokine production and insulin release. The combination of immunosuppressive and insulinotropic activities together with very low cytotoxicity suggests that RP-27 may represent a template for the development of an agent for use in anti-inflammatory and Type 2 diabetes therapies.


Assuntos
Anti-Inflamatórios , Peptídeos Catiônicos Antimicrobianos , Hipoglicemiantes , Células Secretoras de Insulina/imunologia , Proteínas de Anfíbios/química , Proteínas de Anfíbios/farmacologia , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Células Cultivadas , Hipoglicemiantes/química , Hipoglicemiantes/farmacologia , Secreção de Insulina/efeitos dos fármacos , Células Secretoras de Insulina/citologia , Interleucina-10/metabolismo , Interleucina-1beta/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Conformação Molecular , Relação Estrutura-Atividade , Fator de Necrose Tumoral alfa/metabolismo
19.
Soft Matter ; 15(37): 7509-7526, 2019 Sep 25.
Artigo em Inglês | MEDLINE | ID: mdl-31528961

RESUMO

Antimicrobial peptides (AMPs) are naturally-occurring peptide antibiotics. AMPs are typically cationic and utilize their electrostatic interactions with the bacterial membrane to selectively attack bacteria. The way they work has inspired a vigorous search for optimized peptides for fighting resistant bacteria. Here, we present a physical model of membrane selectivity of AMPs. The challenge for theoretical modeling of membrane-peptide systems arises from the simultaneous presence of several competing effects, including lipid demixing and peptide-peptide interactions on the membrane surface. We first examine critically a number of models of peptide-membrane interactions and map out one, which incorporates adequately these competing effects as well as the geometry of various regions in membranes, occupied by bound peptides, anionic lipids within the interaction range of each peptide, and those outside this range. This effort leads to a systematically-improved model for peptide selectivity. Using the model, we relate peptide's intrinsic (Ccell-independent) selectivity to an apparent, Ccell-dependent one, and clarify the relative roles of peptide parameters and cell densities in determining their selectivity. This relationship suggests that the selectivity is more sensitive to peptide parameters at low cell densities; as a result, the optimal peptide charge, at which the selectivity is maximized, increases with the cell density in such a manner that this notion becomes less meaningful at high cell densities.


Assuntos
Peptídeos Catiônicos Antimicrobianos/química , Membrana Celular/química , Termodinâmica , Peptídeos Catiônicos Antimicrobianos/farmacologia , Membrana Celular/efeitos dos fármacos , Bicamadas Lipídicas/química , Modelos Teóricos
20.
Chemosphere ; 226: 915-923, 2019 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-31509921

RESUMO

Fine particulate matter ≤2.5 µm (PM2.5) is a prominent global public health risk factor that can cause respiratory infection by downregulating the amounts of antimicrobial proteins and peptides (AMPs). Both salivary agglutinin (SAG) and surfactant protein D (SPD) are important AMPs in respiratory mucosal fluid, providing protection against airway pathogen invasion and infection by inducing microbial aggregation and enhancing pathogen clearance. However, the relationship between PM2.5 and these AMPs is unclear. To better understand the relationship between PM2.5 and airway innate immune defenses, we review the respiratory antimicrobial activities of SAG and SPD, as well as the adverse effects of PM2.5 on airway innate antimicrobial defense. We speculate there exists a dual effect between PM2.5 and respiratory antimicrobial activity, which means that PM2.5 suppresses respiratory antimicrobial activity through downregulating airway AMPs, while airway AMPs accelerate PM2.5 clearance by inducing PM2.5 microbial aggregation. We propose further research on the relationship between PM2.5 and these AMPs.


Assuntos
Aglutininas/farmacologia , Antibacterianos/farmacologia , Imunidade Inata/efeitos dos fármacos , Material Particulado/efeitos adversos , Proteína D Associada a Surfactante Pulmonar/farmacologia , Sistema Respiratório/efeitos dos fármacos , Infecções Respiratórias/tratamento farmacológico , Peptídeos Catiônicos Antimicrobianos/farmacologia , Humanos , Infecções Respiratórias/induzido quimicamente
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