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1.
Molecules ; 26(6)2021 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-33806967

RESUMO

Bats are unique in their potential to serve as reservoir hosts for intracellular pathogens. Recently, the impact of COVID-19 has relegated bats from biomedical darkness to the frontline of public health as bats are the natural reservoir of many viruses, including SARS-Cov-2. Many bat genomes have been sequenced recently, and sequences coding for antimicrobial peptides are available in the public databases. Here we provide a structural analysis of genome-predicted bat cathelicidins as components of their innate immunity. A total of 32 unique protein sequences were retrieved from the NCBI database. Interestingly, some bat species contained more than one cathelicidin. We examined the conserved cysteines within the cathelin-like domain and the peptide portion of each sequence and revealed phylogenetic relationships and structural dissimilarities. The antibacterial, antifungal, and antiviral activity of peptides was examined using bioinformatic tools. The peptides were modeled and subjected to docking analysis with the region binding domain (RBD) region of the SARS-CoV-2 Spike protein. The appearance of multiple forms of cathelicidins verifies the complex microbial challenges encountered by these species. Learning more about antiviral defenses of bats and how they drive virus evolution will help scientists to investigate the function of antimicrobial peptides in these species.


Assuntos
Catelicidinas/química , Catelicidinas/farmacologia , Quirópteros/genética , Glicoproteína da Espícula de Coronavírus/metabolismo , Animais , Antibacterianos/química , Antibacterianos/farmacologia , Antifúngicos/química , Antifúngicos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Antivirais/química , Antivirais/farmacologia , Sítios de Ligação , Catelicidinas/genética , Catelicidinas/metabolismo , Biologia Computacional/métodos , Simulação por Computador , Genoma , Simulação de Acoplamento Molecular , Filogenia
2.
Food Chem ; 352: 129220, 2021 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-33684717

RESUMO

Cationic antimicrobial peptides have raised interest as attractive alternatives to classical antibiotics, and also have utility in preventing food spoilage. We set out to enrich cationic antimicrobial peptides from milk hydrolysates using gels containing various ratios of anionic pectin/alginate. All processes were carried out with food-grade materials in order to suggest food-safe methods suited for producing food ingredients or supplements. Hydrolysed caseinate peptides retained in the gel fraction, identified by mass spectrometry, were enriched for potential antimicrobial peptides, as judged by a computational predictor of antimicrobial activity. Peptides retained in a 60:40 pectin:alginate gel fraction had a strong antimicrobial effect against 8 tested bacterial strains with a minimal inhibitory concentration of 1.5-5 mg/mL, while the unfractionated hydrolysate only had a detectable effect in one of the eight strains. Among 110 predicted antimicrobial peptides in the gel fraction, four are known antimicrobial peptides, HKEMPFPK, TTMPLW, YYQQKPVA and AVPYPQR. These results highlight the potential of pectin/alginate food-gels based processes as safe, fast, cost-effective methods to separate and enrich for antimicrobial peptides from complex food protein hydrolysates.


Assuntos
Alginatos/química , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Leite/química , Pectinas/química , Hidrolisados de Proteína/química , Sequência de Aminoácidos , Animais , Géis , Testes de Sensibilidade Microbiana
4.
Arch Insect Biochem Physiol ; 106(3): e21771, 2021 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-33644898

RESUMO

Antimicrobial proteins (AMPs) are small, cationic proteins that exhibit activity against bacteria, viruses, parasites, fungi as well as boost host-specific innate immune responses. Insects produce these AMPs in the fat body and hemocytes, and release them into the hemolymph upon microbial infection. Hemolymph was collected from the bacterially immunized fifth instar larvae of tasar silkworm, Antheraea mylitta, and an AMP was purified by organic solvent extraction followed by size exclusion and reverse-phase high-pressure liquid chromatography. The purity of AMP was confirmed by thin-layer chromatography and sodium dodecyl sulfate-polyacrylamide gel electrophoresis analysis. The molecular mass was determined by matrix-assisted laser desorption ionization-time of flight mass spectrometry as 14 kDa, and hence designated as AmAMP14. Peptide mass fingerprinting of trypsin-digested AmAMP14 followed by de novo sequencing of one peptide fragment by tandem mass spectrometry analysis revealed the amino acid sequences as CTSPKQCLPPCK. No homology was found in the database search and indicates it as a novel AMP. The minimum inhibitory concentration of the purified AmAMP14 was determined against Escherichia coli, Staphylococcus aureus, and Candida albicans as 30, 60, and 30 µg/ml, respectively. Electron microscopic examination of the AmAMP14-treated cells revealed membrane damage and release of cytoplasmic contents. All these results suggest the production of a novel 14 kDa AMP in the hemolymph of A. mylitta to provide defense against microbial infection.


Assuntos
Peptídeos Catiônicos Antimicrobianos , Hemolinfa/metabolismo , Proteínas de Insetos/isolamento & purificação , Mariposas/metabolismo , Animais , Antibacterianos/química , Antibacterianos/isolamento & purificação , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/isolamento & purificação , Peptídeos Catiônicos Antimicrobianos/farmacologia , Candida albicans/efeitos dos fármacos , Cromatografia em Gel/métodos , Cromatografia Líquida de Alta Pressão/métodos , Escherichia coli/efeitos dos fármacos , Proteínas de Insetos/química , Proteínas de Insetos/metabolismo , Proteínas de Insetos/farmacologia , Larva/metabolismo , Extração Líquido-Líquido/métodos , Testes de Sensibilidade Microbiana , Staphylococcus aureus/efeitos dos fármacos
5.
Nat Commun ; 12(1): 1285, 2021 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-33627652

RESUMO

The host defence peptide cathelicidin (LL-37 in humans, mCRAMP in mice) is released from neutrophils by de-granulation, NETosis and necrotic death; it has potent anti-pathogen activity as well as being a broad immunomodulator. Here we report that cathelicidin is a powerful Th17 potentiator which enhances aryl hydrocarbon receptor (AHR) and RORγt expression, in a TGF-ß1-dependent manner. In the presence of TGF-ß1, cathelicidin enhanced SMAD2/3 and STAT3 phosphorylation, and profoundly suppressed IL-2 and T-bet, directing T cells away from Th1 and into a Th17 phenotype. Strikingly, Th17, but not Th1, cells were protected from apoptosis by cathelicidin. We show that cathelicidin is released by neutrophils in mouse lymph nodes and that cathelicidin-deficient mice display suppressed Th17 responses during inflammation, but not at steady state. We propose that the neutrophil cathelicidin is required for maximal Th17 differentiation, and that this is one method by which early neutrophilia directs subsequent adaptive immune responses.


Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Neutrófilos/citologia , Neutrófilos/efeitos dos fármacos , Células Th17/metabolismo , Animais , Diferenciação Celular/efeitos dos fármacos , Células Cultivadas , Ensaio de Imunoadsorção Enzimática , Feminino , Citometria de Fluxo , Humanos , Imuno-Histoquímica , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Fosforilação/genética , Fosforilação/fisiologia , Proteínas Citotóxicas Formadoras de Poros/farmacologia , Fator de Transcrição STAT3/genética , Fator de Transcrição STAT3/metabolismo , Proteína Smad2/genética , Proteína Smad2/metabolismo , Proteína Smad3/genética , Proteína Smad3/metabolismo , Células Th1/citologia , Células Th1/efeitos dos fármacos , Células Th1/metabolismo , Células Th17/citologia , Células Th17/efeitos dos fármacos
6.
Biochim Biophys Acta Biomembr ; 1863(1): 183480, 2021 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-32979382

RESUMO

Anticancer chemo- and targeted therapies are limited in some cases due to strong side effects and/or drug resistance. Peptides have received renascent interest as anticancer therapeutics and are currently being considered as alternatives and/or as complementary to biologics and small-molecule drugs. Gomesin, a disulfide-rich host defense peptide expressed in the Brazilian spider Acanthoscurria gomesiana selectively targets and disrupts cancer cell membranes. In the current study, we employed a range of biophysical methodologies with model membranes and bioassays to investigate the use of a cyclic analogue of gomesin as a drug scaffold to internalize cancer cells. We found that cyclic gomesin can internalize cancer cells via endocytosis and direct membrane permeation. In addition, we designed an improved non-disruptive and non-toxic cyclic gomesin analogue by incorporating D-amino acids within the scaffold. This improved analogue retained the ability to enter cancer cells and can be used as a scaffold to deliver drugs. Efforts to investigate the internalization mechanism used by host defense peptides, and to improve their stability, potency, selectivity and ability to permeate cancer cell membranes will increase the opportunities to repurpose peptides as templates for designing alternative anticancer therapeutic leads.


Assuntos
Peptídeos Catiônicos Antimicrobianos , Proteínas de Artrópodes , Membrana Celular/metabolismo , Sistemas de Liberação de Medicamentos , Neoplasias/metabolismo , Aranhas/química , Animais , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacocinética , Peptídeos Catiônicos Antimicrobianos/farmacologia , Proteínas de Artrópodes/química , Proteínas de Artrópodes/farmacocinética , Proteínas de Artrópodes/farmacologia , Membrana Celular/patologia , Células HeLa , Humanos , Células MCF-7 , Neoplasias/tratamento farmacológico , Neoplasias/patologia
7.
J Sci Food Agric ; 101(1): 229-239, 2021 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-32627181

RESUMO

BACKGROUND: Synthetic fungicides are most commonly used for controlling postharvest disease of fruit, although they can cause the emergence of drug-resistant strains, environmental pollution and fruit safety issues. Bacillomycin D (BD), a novel antifungal lipopeptide, and chitosan (CTS) are applied for the preservation of cherry tomato. RESULTS: The combination of BD and CTS showed an additive inhibition on the growth of Rhizopus stolonifer and Botrytis cinerea compared to that of its individual compound. In addition, BD + CTS reduced the incidence of soft rot and gray mold in cherry tomato caused by R. stolonifer and B. cinerea, respectively. Tomato treated with BD + CTS exhibited a lower weight loss and higher firmness and higher contents of total soluble solids, titratable acidity and ascorbic acid compared to those treated with sterile water (control). The kinetics models demonstrated that the shelf life of cherry tomato treated with BD + CTS could be extended by approximately 15 days longer than the control. CONCLUSION: The utilization of BD + CTS provided a novel strategy for reducing postharvest fungal rot and maintaining the storage quality of cherry tomato. © 2020 Society of Chemical Industry.


Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Botrytis/efeitos dos fármacos , Quitosana/farmacologia , Conservação de Alimentos/métodos , Fungicidas Industriais/farmacologia , Lycopersicon esculentum/microbiologia , Rhizopus/efeitos dos fármacos , Botrytis/crescimento & desenvolvimento , Sinergismo Farmacológico , Frutas/química , Frutas/microbiologia , Lycopersicon esculentum/química , Doenças das Plantas/microbiologia , Rhizopus/crescimento & desenvolvimento
9.
PLoS One ; 15(12): e0243315, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-33326455

RESUMO

Chronic rhinosinusitis (CRS) is a chronic disease that involves long-term inflammation of the nasal cavity and paranasal sinuses. Bacterial biofilms present on the sinus mucosa of certain patients reportedly exhibit resistance against traditional antibiotics, as evidenced by relapse, resulting in severe disease. The aim of this study was to determine the killing activity of human cathelicidin antimicrobial peptides (LL-37, LL-31) and their D-enantiomers (D-LL-37, D-LL-31), alone and in combination with conventional antibiotics (amoxicillin; AMX and tobramycin; TOB), against bacteria grown as biofilm, and to investigate the biological activities of the peptides on human lung epithelial cells. D-LL-31 was the most effective peptide against bacteria under biofilm-stimulating conditions based on IC50 values. The synergistic effect of D-LL-31 with AMX and TOB decreased the IC50 values of antibiotics by 16-fold and could eliminate the biofilm matrix in all tested bacterial strains. D-LL-31 did not cause cytotoxic effects in A549 cells at 25 µM after 24 h of incubation. Moreover, a cytokine array indicated that there was no significant induction of the cytokines involving in immunopathogenesis of CRS in the presence of D-LL-31. However, a tissue-remodeling-associated protein was observed that may prevent the progression of nasal polyposis in CRS patients. Therefore, a combination of D-LL-31 with AMX or TOB may improve the efficacy of currently used antibiotics to kill biofilm-embedded bacteria and eliminate the biofilm matrix. This combination might be clinically applicable for treatment of patients with biofilm-associated CRS.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias/crescimento & desenvolvimento , Fenômenos Fisiológicos Bacterianos/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Células Epiteliais/microbiologia , Pulmão/microbiologia , Rinite , Sinusite , Células A549 , Adolescente , Adulto , Idoso , Biofilmes/crescimento & desenvolvimento , Doença Crônica , Células Epiteliais/metabolismo , Feminino , Humanos , Pulmão/metabolismo , Pulmão/patologia , Masculino , Pessoa de Meia-Idade , Rinite/tratamento farmacológico , Rinite/microbiologia , Rinite/patologia , Sinusite/tratamento farmacológico , Sinusite/microbiologia , Sinusite/patologia
10.
Int J Mol Sci ; 21(24)2020 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-33352806

RESUMO

Recent studies performed on the invertebrate model Hirudo verbana (medicinal leech) suggest that the T2 ribonucleic enzyme HvRNASET2 modulates the leech's innate immune response, promoting microbial agglutination and supporting phagocytic cells recruitment in challenged tissues. Indeed, following injection of both lipoteichoic acid (LTA) and Staphylococcus aureus in the leech body wall, HvRNASET2 is expressed by leech type I granulocytes and induces bacterial aggregation to aid macrophage phagocytosis. Here, we investigate the HvRNASET2 antimicrobial role, in particular assessing the effects on the Gram-negative bacteria Escherichia coli. For this purpose, starting from the three-dimensional molecule reconstruction and in silico analyses, the antibacterial activity was evaluated both in vitro and in vivo. The changes induced in treated bacteria, such as agglutination and alteration in wall integrity, were observed by means of light, transmission and scanning electron microscopy. Moreover, immunogold, AMPs (antimicrobial peptides) and lipopolysaccharide (LPS) binding assays were carried out to evaluate HvRNASET2 interaction with the microbial envelopes and the ensuing ability to affect microbial viability. Finally, in vivo experiments confirmed that HvRNASET2 promotes a more rapid phagocytosis of bacterial aggregates by macrophages, representing a novel molecule for counteracting pathogen infections and developing alternative solutions to improve human health.


Assuntos
Antibacterianos/farmacologia , Escherichia coli/efeitos dos fármacos , Hirudo medicinalis/crescimento & desenvolvimento , Viabilidade Microbiana/efeitos dos fármacos , Ribonucleases/química , Ribonucleases/farmacologia , Aglutinação , Sequência de Aminoácidos , Animais , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Escherichia coli/crescimento & desenvolvimento , Escherichia coli/metabolismo , Hirudo medicinalis/efeitos dos fármacos , Hirudo medicinalis/metabolismo , Imageamento Tridimensional , Imunidade Inata , Macrófagos/efeitos dos fármacos , Fagocitose , Conformação Proteica , Homologia de Sequência de Aminoácidos
11.
Mar Drugs ; 18(12)2020 Dec 17.
Artigo em Inglês | MEDLINE | ID: mdl-33348729

RESUMO

Edwardsiella tarda can cause fatal gastro-/extraintestinal diseases in fish and humans. Overuse of antibiotics has led to antibiotic resistance and contamination in the environment, which highlights the need to find new antimicrobial agents. In this study, the marine peptide-N6 was amidated at its C-terminus to generate N6NH2. The antibacterial activity of N6 and N6NH2 against E. tarda was evaluated in vitro and in vivo; their stability, toxicity and mode of action were also determined. Minimal inhibitory concentrations (MICs) of N6 and N6NH2 against E. tarda were 1.29-3.2 µM. Both N6 and N6NH2 killed bacteria by destroying the cell membrane of E. tarda and binding to lipopolysaccharide (LPS) and genomic DNA. In contrast with N6, N6NH2 improved the stability toward trypsin, reduced hemolysis (by 0.19% at a concentration of 256 µg/mL) and enhanced the ability to penetrate the bacterial outer and inner membrane. In the model of fish peritonitis caused by E. tarda, superior to norfloxacin, N6NH2 improved the survival rate of fish, reduced the bacterial load on the organs, alleviated the organ injury and regulated the immunity of the liver and kidney. These data suggest that the marine peptide N6NH2 may be a candidate for novel antimicrobial agents against E. tarda infections.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Edwardsiella tarda/efeitos dos fármacos , Infecções por Enterobacteriaceae/tratamento farmacológico , Infecções por Enterobacteriaceae/virologia , Doenças dos Peixes/tratamento farmacológico , Animais , Antibacterianos/química , Peptídeos Catiônicos Antimicrobianos/química , Membrana Celular/efeitos dos fármacos , Infecções por Enterobacteriaceae/microbiologia , Doenças dos Peixes/microbiologia , Doenças dos Peixes/patologia , Proteínas de Peixes , Rim/patologia , Fígado/patologia , Testes de Sensibilidade Microbiana , Norfloxacino/uso terapêutico , Peritonite/tratamento farmacológico , Peritonite/etiologia , Relação Estrutura-Atividade , Análise de Sobrevida
12.
Int J Mol Sci ; 21(24)2020 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-33352981

RESUMO

Many peptides interact with biological membranes, but elucidating these interactions is challenging because cellular membranes are complex and peptides are structurally flexible. To contribute to understanding how the membrane-active peptides behave near the membranes, we investigated peptide structural changes in different lipid surroundings. We focused on two antimicrobial peptides, anoplin and W-MreB1-9, and one cell-penetrating peptide, (KFF)3K. Firstly, by using circular dichroism spectroscopy, we determined the secondary structures of these peptides when interacting with micelles, liposomes, E. coli lipopolysaccharides, and live E. coli bacteria. The peptides were disordered in the buffer, but anoplin and W-MreB1-9 displayed lipid-induced helicity. Yet, structural changes of the peptide depended on the composition and concentration of the membranes. Secondly, we quantified the destructive activity of peptides against liposomes by monitoring the release of a fluorescent dye (calcein) from the liposomes treated with peptides. We observed that only for anoplin and W-MreB1-9 calcein leakage from liposomes depended on the peptide concentration. Thirdly, bacterial growth inhibition assays showed that peptide conformational changes, evoked by the lipid environments, do not directly correlate with the antimicrobial activity of the peptides. However, understanding the relation between peptide structural properties, mechanisms of membrane disruption, and their biological activities can guide the design of membrane-active peptides.


Assuntos
Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Penetradores de Células/química , Proteínas de Escherichia coli/química , Peptídeos/química , Venenos de Vespas/química , Sequência de Aminoácidos , Peptídeos Catiônicos Antimicrobianos/farmacologia , Membrana Celular/química , Peptídeos Penetradores de Células/síntese química , Peptídeos Penetradores de Células/isolamento & purificação , Dicroísmo Circular , Bicamadas Lipídicas/química , Peptídeos/síntese química , Peptídeos/isolamento & purificação , Estrutura Secundária de Proteína , Venenos de Vespas/farmacologia
13.
Int J Mol Sci ; 21(24)2020 Dec 10.
Artigo em Inglês | MEDLINE | ID: mdl-33321906

RESUMO

Bacterial biofilms are a serious threat for human health, and the Gram-positive bacterium Staphylococcus aureus is one of the microorganisms that can easily switch from a planktonic to a sessile lifestyle, providing protection from a large variety of adverse environmental conditions. Dormant non-dividing cells with low metabolic activity, named persisters, are tolerant to antibiotic treatment and are the principal cause of recalcitrant and resistant infections, including skin infections. Antimicrobial peptides (AMPs) hold promise as new anti-infective agents to treat such infections. Here for the first time, we investigated the activity of the frog-skin AMP temporin G (TG) against preformed S. aureus biofilm including persisters, as well as its efficacy in combination with tobramycin, in inhibiting S. aureus growth. TG was found to provoke ~50 to 100% reduction of biofilm viability in the concentration range from 12.5 to 100 µM vs ATCC and clinical isolates and to be active against persister cells (about 70-80% killing at 50-100 µM). Notably, sub-inhibitory concentrations of TG in combination with tobramycin were able to significantly reduce S. aureus growth, potentiating the antibiotic power. No critical cytotoxicity was detected when TG was tested in vitro up to 100 µM against human keratinocytes, confirming its safety profile for the development of a new potential anti-infective drug, especially for treatment of bacterial skin infections.


Assuntos
Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Biofilmes/efeitos dos fármacos , Staphylococcus aureus/efeitos dos fármacos , Sinergismo Farmacológico , Tobramicina/farmacologia
14.
Nat Commun ; 11(1): 5021, 2020 10 06.
Artigo em Inglês | MEDLINE | ID: mdl-33024117

RESUMO

Engineered biocircuits designed with biological components have the capacity to expand and augment living functions. Here we demonstrate that proteases can be integrated into digital or analog biocircuits to process biological information. We first construct peptide-caged liposomes that treat protease activity as two-valued (i.e., signal is 0 or 1) operations to construct the biological equivalent of Boolean logic gates, comparators and analog-to-digital converters. We use these modules to assemble a cell-free biocircuit that can combine with bacteria-containing blood, quantify bacteria burden, and then calculate and unlock a selective drug dose. By contrast, we treat protease activity as multi-valued (i.e., signal is between 0 and 1) by controlling the degree to which a pool of enzymes is shared between two target substrates. We perform operations on these analog values by manipulating substrate concentrations and combine these operations to solve the mathematical problem Learning Parity with Noise (LPN). These results show that protease activity can be used to process biological information by binary Boolean logic, or as multi-valued analog signals under conditions where substrate resources are shared.


Assuntos
Sistemas de Liberação de Medicamentos/métodos , Peptídeo Hidrolases/metabolismo , Peptídeos Catiônicos Antimicrobianos/administração & dosagem , Peptídeos Catiônicos Antimicrobianos/farmacologia , Proteínas da Membrana Bacteriana Externa/metabolismo , Eritrócitos/microbiologia , Escherichia coli , Proteínas de Escherichia coli/metabolismo , Hemólise , Humanos , Lipossomos , Matemática , Pró-Fármacos , Biologia Sintética/métodos
15.
Exp Parasitol ; 218: 107987, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32891601

RESUMO

The protozoan parasite Leishmania spp. causes leishmaniases, a group of diseases creating serious health problems in many parts of the world with significant resistance to existing drugs. Insect derived antimicrobial peptides are promising alternatives to conventional drugs against several human disease-causing pathogens because they do not generate resistance. Halictine-2, a novel antimicrobial peptide from the venom of eusocial honeybee, Halictus sexcinctus showed significant anti-leishmanial activity in vitro, towards two life forms of the dimorphic parasite, the free-swimming infective metacyclic promastigotes and the intracellular amastigotes responsible for the systemic infection. The anti-leishmanial activity of the native peptide (P5S) was significantly enhanced by serine to threonine substitution at position 5 (P5T). The peptide showed a propensity to form α-helices after substitution at position-5, conferring amphipathicity. Distinct pores observed on the promastigote membrane after P5T exposure suggested a mechanism of disruption of cellular integrity. Biochemical alterations in the promastigotes after P5T exposure included generation of increased oxygen radicals with mitochondrial Ca2+ release, loss of mitochondrial membrane potential, reduction in total ATP content and increased mitochondrial mass, resulting in quick bioenergetic and chemiosmotic collapse leading to cell death characterized by DNA fragmentation. P5T was able to reduce intracellular amastigote burden in an in vitro model of Leishmania infection but did not alter the proinflammatory cytokines like TNF-α and IL-6. The ability of the P5T peptide to kill the Leishmania parasite with negligible haemolytic activity towards mouse macrophages and human erythrocytes respectively, demonstrates its potential to be considered as a future antileishmanial drug candidate.


Assuntos
Peptídeos Catiônicos Antimicrobianos/farmacologia , Antiprotozoários/farmacologia , Apoptose , Leishmania tropica/efeitos dos fármacos , Substituição de Aminoácidos , Animais , Peptídeos Catiônicos Antimicrobianos/química , Antiprotozoários/química , Venenos de Abelha/química , Cálcio/análise , Cálcio/metabolismo , Linhagem Celular , Dicroísmo Circular , Fragmentação do DNA , Fluoresceína-5-Isotiocianato , Corantes Fluorescentes , Fluorometria , Humanos , Leishmania tropica/ultraestrutura , Leishmaniose Visceral/parasitologia , Macrófagos Peritoneais , Potencial da Membrana Mitocondrial , Camundongos , Camundongos Endogâmicos C57BL , Microscopia Confocal , Microscopia Eletrônica de Varredura , Mitocôndrias/química , Tamanho Mitocondrial , Espécies Reativas de Oxigênio/isolamento & purificação , Espectrometria de Massas por Ionização e Dessorção a Laser Assistida por Matriz , Superóxidos/isolamento & purificação
16.
Life Sci ; 261: 118381, 2020 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-32891611

RESUMO

AIM: Development and design of efficient wound dressings are subject of intensive investigations either in basic or in clinical researches. Although, hydrogel-based wound dressings have gained increasing attention and showed beneficial results in term of improved wound healing effect, they are not yet able to heal complex wounds. This study was conducted in an attempt to improve wound healing properties and introduce a novel potential wound dressing. MATERIAL AND METHODS: Wharton's jelly derived-mesenchymal stem cells (WJ-MSCs) were transfected with a recombinant construct encoding hCAP-18/LL-37 gene which has several important functions in wound healing process. Next, the conditioned medium (CM) of the transfected cells (LL-37-MSCs) was harvested, and its concentrate was formulated in a sodium alginate (SA)/gelatin (G) hydrogel. Finally, the wound healing efficacy of the hydrogel-CM combination was evaluated in an excision wound model in rat. KEY FINDINGS: In vitro findings exhibited biocompatibility, biodegradability, acceptable mechanical properties, sustained release, and capacity to absorb wound exudate for the hydrogel. In vivo, the hydrogel effectively accelerated wound contraction and promoted wound healing in comparison to controls. CONCLUSION: Although further investigations including preclinical and clinical studies are required, our findings strongly suggest that the hydrogel might be considered as a potential novel wound dressing for healing of a variety of wounds.


Assuntos
Alginatos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Meios de Cultivo Condicionados/farmacologia , Gelatina/química , Hidrogéis/química , Células-Tronco Mesenquimais/química , Geleia de Wharton/citologia , Cicatrização/efeitos dos fármacos , Animais , Morte Celular/efeitos dos fármacos , Modelos Animais de Doenças , Humanos , Masculino , Ratos Wistar , Espectroscopia de Infravermelho com Transformada de Fourier , Suínos , Fator A de Crescimento do Endotélio Vascular/metabolismo
17.
Adv Exp Med Biol ; 1267: 117-133, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32894480

RESUMO

Antibiotic resistance is a global epidemic, becoming increasingly pressing due to its rapid spread. There is thus a critical need to develop new therapeutic approaches. In addition to searching for new antibiotics, looking into existing mechanisms of natural host defense may enable researchers to improve existing defense mechanisms, and to develop effective, synthetic drugs guided by natural principles. Histones, primarily known for their role in condensing mammalian DNA, are antimicrobial and share biochemical similarities with antimicrobial peptides (AMPs); however, the mechanism by which histones kill bacteria is largely unknown. Both AMPs and histones are similar in size, cationic, contain a high proportion of hydrophobic amino acids, and possess the ability to form alpha helices. AMPs, which mostly kill bacteria through permeabilization or disruption of the biological membrane, have recently garnered significant attention for playing a key role in host defenses. This chapter outlines the structure and function of histone proteins as they compare to AMPs and provides an overview of their role in innate immune responses, especially regarding the action of specific histones against microorganisms and their potential mechanism of action against microbial pathogens.


Assuntos
Antibacterianos/química , Antibacterianos/imunologia , Bactérias/imunologia , Histonas/química , Histonas/imunologia , Animais , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias/efeitos dos fármacos , Histonas/farmacologia , Imunidade Inata
18.
PLoS Negl Trop Dis ; 14(8): e0008660, 2020 08.
Artigo em Inglês | MEDLINE | ID: mdl-32866199

RESUMO

Aedes mosquitoes can transmit dengue and several other severe vector-borne viral diseases, thereby influencing millions of people worldwide. Insects primarily control and clear the viral infections via their innate immune systems. Mitogen-Activated Protein Kinases (MAPKs) and antimicrobial peptides (AMPs) are both evolutionarily conserved components of the innate immune systems. In this study, we investigated the role of MAPKs in Aedes mosquitoes following DENV infection by using genetic and pharmacological approaches. We demonstrated that knockdown of ERK, but not of JNK or p38, significantly enhances the viral replication in Aedes mosquito cells. The Ras/ERK signaling is activated in both the cells and midguts of Aedes mosquitoes following DENV infection, and thus plays a role in restricting the viral infection, as both genetic and pharmacological activation of the Ras/ERK pathway significantly decreases the viral titers. In contrast, inhibition of the Ras/ERK pathway enhances DENV infection. In addition, we identified a signaling crosstalk between the Ras/ERK pathway and DENV-induced AMPs in which defensin C participates in restricting DENV infection in Aedes mosquitoes. Our results reveal that the Ras/ERK signaling pathway couples AMPs to mediate the resistance of Aedes mosquitoes to DENV infection, which provides a new insight into understanding the crosstalk between MAPKs and AMPs in the innate immunity of mosquito vectors during the viral infection.


Assuntos
Aedes/virologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Vírus da Dengue/imunologia , Quinases de Proteína Quinase Ativadas por Mitógeno/farmacologia , Mosquitos Vetores/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Animais , Anti-Infecciosos/farmacologia , Linhagem Celular , Sistema Digestório/virologia , Feminino , Perfilação da Expressão Gênica , Técnicas de Silenciamento de Genes , Imunidade Inata , Quinases de Proteína Quinase Ativadas por Mitógeno/genética , Quinases de Proteína Quinase Ativadas por Mitógeno/metabolismo , Mosquitos Vetores/virologia , Carga Viral , Replicação Viral/efeitos dos fármacos
19.
Nat Commun ; 11(1): 3894, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32753597

RESUMO

Here, we demonstrate the self-assembly of the antimicrobial human LL-37 active core (residues 17-29) into a protein fibril of densely packed helices. The surface of the fibril encompasses alternating hydrophobic and positively charged zigzagged belts, which likely underlie interactions with and subsequent disruption of negatively charged lipid bilayers, such as bacterial membranes. LL-3717-29 correspondingly forms wide, ribbon-like, thermostable fibrils in solution, which co-localize with bacterial cells. Structure-guided mutagenesis analyses supports the role of self-assembly in antibacterial activity. LL-3717-29 resembles, in sequence and in the ability to form amphipathic helical fibrils, the bacterial cytotoxic PSMα3 peptide that assembles into cross-α amyloid fibrils. This argues helical, self-assembling, basic building blocks across kingdoms of life and points to potential structural mimicry mechanisms. The findings expose a protein fibril which performs a biological activity, and offer a scaffold for functional and durable biomaterials for a wide range of medical and technological applications.


Assuntos
Antibacterianos/química , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/química , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias/efeitos dos fármacos , Amiloide/metabolismo , Animais , Peptídeos Catiônicos Antimicrobianos/genética , Bactérias/metabolismo , Benzotiazóis , Catelicidinas/farmacologia , Cristalografia por Raios X , Gorilla gorilla , Humanos , Testes de Sensibilidade Microbiana , Micrococcus luteus/efeitos dos fármacos , Microscopia Confocal , Microscopia Eletrônica de Transmissão , Modelos Moleculares , Conformação Proteica , Staphylococcus hominis/efeitos dos fármacos , Difração de Raios X
20.
Sheng Wu Gong Cheng Xue Bao ; 36(7): 1277-1282, 2020 Jul 25.
Artigo em Chinês | MEDLINE | ID: mdl-32748585

RESUMO

Microbial biofilm, a consortium of microbial cells protected by a self-produced polymer matrix, is considered as one main cause of current bacterial drug resistance. As a new type of antimicrobial agents, antimicrobial peptides provide a new strategy for the treatment of antibiotic resistant bacteria biofilm infections. Antimicrobial peptides have shown unique advantages in preventing microbial colonization of surfaces, killing bacteria in biofilms or disrupting the mature biofilm structure. This review systemically analyzes published data in the recent 30 years to summarize the possible anti-biofilm mechanisms of antimicrobial peptides. We hope that this review can provide reference for the treatment of infectious diseases by pathogenic microbial biofilm.


Assuntos
Peptídeos Catiônicos Antimicrobianos , Bactérias , Biofilmes , Antibacterianos/farmacologia , Peptídeos Catiônicos Antimicrobianos/farmacologia , Bactérias/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Farmacorresistência Bacteriana/efeitos dos fármacos , Testes de Sensibilidade Microbiana , Pesquisa/tendências
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