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1.
J Med Chem ; 67(4): 2512-2528, 2024 Feb 22.
Artigo em Inglês | MEDLINE | ID: mdl-38335999

RESUMO

Insect defensins are a large family of antimicrobial peptides primarily active against Gram-positive bacteria. Here, we explore their hidden anti-Gram-negative bacterial potential via a nature-guided strategy inspired by natural deletion variants of Drosophila defensins. Referring to these variants, we deleted the equivalent region of an insect defensin with the first cysteine-containing N-terminus, and the last three cysteine-containing C-terminal regions remained. This 15-mer peptide exhibits low solubility and specifically targets Gram-positive bacteria. Further deletion of alanine-9 remarkably improves its solubility, unmasks its hidden anti-Gram-negative bacterial activity, and alters its states in different environments. Intriguingly, compared with the oxidized form, the 14-mer reduced peptide shows increased activity on Gram-positive and Gram-negative bacteria through a membrane-disruptive mechanism. The broad-spectrum activity and tolerance to high-salt environments and human serum, together with no toxicity to mammalian or human cells, make it a promising candidate for the design of new peptide antibiotics against Gram-negative bacterial infections.


Assuntos
Antibacterianos , Cisteína , Animais , Humanos , Sequência de Aminoácidos , Antibacterianos/farmacologia , Bactérias Gram-Negativas , Bactérias Gram-Positivas , Peptídeos/farmacologia , Defensinas/genética , Defensinas/farmacologia , Insetos , Mamíferos
2.
Microbiol Spectr ; 12(2): e0182723, 2024 Feb 06.
Artigo em Inglês | MEDLINE | ID: mdl-38236024

RESUMO

One of the major issues in healthcare today is antibiotic resistance. Antimicrobial peptides (AMPs), a subclass of host defense peptides, have been suggested as a viable solution for the multidrug resistance problem. Legume plants express more than 700 nodule-specific cysteine-rich (NCR) peptides. Three NCR peptides (NCR094, NCR888, and NCR992) were predicted to have antimicrobial activity using in silico AMP prediction programs. This study focused on investigating the roles of the NCRs in antimicrobial activity and antibiofilm activity, followed by in vitro toxicity profiling. Different variants were synthesized, i.e., mutated and truncated derivatives. The effect on the growth of Klebsiella pneumoniae and methicillin-resistant Staphylococcus aureus (MRSA) was monitored post-treatment, and survived cells were counted using an in vitro and ex vivo killing assay. The antibiofilm assay was conducted using subinhibitory concentrations of the NCRs and monitoring K. pneumoniae biomass, followed by crystal violet staining. The cytotoxicity profile was evaluated using erythrocyte hemolysis and leukemia (K562) cell line toxicity assays. Out of the NCRs, NCR094 and NCR992 displayed mainly in vitro and ex vivo bactericidal activity on K. pneumoniae. NCR094 wild type (WT) and NCR992 eradicated K. pneumoniae at different potency; NCR094 and NCR992 killed K. pneumoniae completely at 25 and 50 µM, respectively. However, both peptides in the wild type showed negligible bactericidal effect on MRSA in vitro and ex vivo. NCR094 and its derivatives relatively retained the antimicrobial activity on K. pneumoniae in vitro and ex vivo. NCR992 WT lost its antimicrobial activity on K. pneumoniae ex vivo, yet the different truncated and mutated variants retained some of the antimicrobial role ex vivo. All the different variants of NCR094 had no effect on MRSA in vitro and ex vivo. Similarly, NCR992's variants had a negligible bactericidal role on MRSA in vitro, yet the truncated variants had a significantly high bactericidal effect on MRSA ex vivo. NCR094.3 (cystine replacement variant) and NCR992.1 displayed significant antibiofilm activity more than 90%. NCR992.3 and NCR992.2 displayed more than 50% of antibiofilm activity. All the NCR094 forms had no toxicity, except NCR094.1 (49.38%, SD ± 3.46) and all NCR992 forms (63%-93%), which were above the cutoff (20%). Only NCR992.2 showed low toxicity on K562 (24.8%, SD ± 3.40), yet above the 20% cutoff. This study provided preliminary antimicrobial and safety data for the potential use of these peptides for therapeutical applications.IMPORTANCEThe discovery of new antibiotics is urgently needed, given the global expansion of antibiotic-resistant bacteria and the rising mortality rate. One of the initial lines of defense against microbial infections is antimicrobial peptides (AMPs). Plants can express hundreds of such AMPs as defensins and defensin-like peptides. The nodule-specific cysteine-rich (NCR) peptides are a class of defensin-like peptides that have evolved in rhizobial-legume symbioses. This study screened the antimicrobial activity of a subset of NCR sequences using online computational AMP prediction algorithms. Two novel NCRs, NCR094 and NCR992, with different variants were identified to exhibit antimicrobial activity with various potency on two problematic pathogens, K. pneumoniae and MRSA, using in vitro and ex vivo killing assays. Yet, one variant, NCR094.3, had no toxicity toward human cells and displayed antibiofilm activity, which make it a promising lead for antimicrobial drug development.


Assuntos
Anti-Infecciosos , Medicago truncatula , Staphylococcus aureus Resistente à Meticilina , Humanos , Medicago truncatula/química , Medicago truncatula/metabolismo , Medicago truncatula/microbiologia , Peptídeos Antimicrobianos , Cisteína/metabolismo , Staphylococcus aureus Resistente à Meticilina/metabolismo , Peptídeos Catiônicos Antimicrobianos/farmacologia , Anti-Infecciosos/farmacologia , Antibacterianos/farmacologia , Klebsiella pneumoniae , Verduras , Defensinas/farmacologia , Testes de Sensibilidade Microbiana
3.
J Fish Dis ; 47(4): e13922, 2024 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-38204197

RESUMO

The purpose of this study was to investigate whether a defensin-like antimicrobial peptide (C-13326 peptide) identified in Hermetia illucens could possess protective effect against multidrug-resistant Aeromonas schubertii in hybrid snakehead (Channa maculate ♀ × Channa argus ♂). The cDNA of C-13326 peptide comprised 243 nucleotides encoding 80 amino acids, with six conserved cysteine residues and the classical CSαß structure. The recombinant expression plasmid pPIC9K-C-13326 was constructed and transformed into GS115 Pichia pastoris, and the C-13326 peptide was expressed by induction with 1% methanol. The crude extract of C-13326 peptide was precipitated by ammonium sulfate, assayed by Braford method, detected by tricine-SDS-PAGE, evaluated by BandScan software and identified by liquid chromatography-mass spectrometry. The C-13326 peptide was shown to have inhibitory activity against the growth of multidrug-resistant A. schubertii DM210910 by using the minimum growth inhibitory concentration and Oxford cup method. In addition, scanning electron microscopy analysis suggested that C-13326 peptide inhibited the growth of A. schubertii DM210910 by damaging the bacterial cell membrane. To explore the role of peptide C-13326 in vivo, hybrid snakehead was fed with peptide C-13326 as feed additives for 7 days. The results revealed that C-13326 peptide could significantly down-regulate the expression levels of IL-1ß, IL-8, IL-12 and TNF-α (p < .05), and significantly improved the survival rate of hybrid snakehead after challenging with A. schubertii DM210910. Therefore, the C-13326 peptide is a promising antimicrobial agent for A. schubertii treatment in aquaculture.


Assuntos
Aeromonas , Doenças dos Peixes , Animais , Doenças dos Peixes/prevenção & controle , Doenças dos Peixes/microbiologia , Peixes/genética , Aeromonas/genética , Peptídeos , Defensinas/genética , Defensinas/farmacologia
4.
Int J Immunopathol Pharmacol ; 38: 3946320231223004, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-38217433

RESUMO

The symptoms of celery allergy are mainly presented as oral allergy symptom, but there are several case reports of patients who experienced anaphylaxis. Defensin (Api g 7), as a novel allergen in celery root, was described in 2022 r. The female patient had a history of several episodes of dyspnea and cough, associated with ingestion of spice mixes containing dried celery. Up to the point of hospitalization, there were no objective tests, either sIgE or skin prick tests, that would confirm celery sensitization. During hospitalization, patient had a positive double-blind placebo-controlled food challenge with cooked celery. The patient was sensitized to mugwort defensin Art v 1. An inhibition assay with celery allergen extract was performed to prove cross-sensitization between Art v 1 and celery allergen responsible for symptoms in the patient. In conclusion, Api g 7 is an important celery allergen that can be responsible for severe reactions. Its cross-reactivity with Art v 1 is characteristic. Negative diagnostic tests with celery do not exclude Api g 7 sensitization.


Assuntos
Anafilaxia , Hipersensibilidade Alimentar , Humanos , Feminino , Anafilaxia/diagnóstico , Hipersensibilidade Alimentar/diagnóstico , Pólen , Proteínas de Plantas/efeitos adversos , Alérgenos , Defensinas , Testes Cutâneos/efeitos adversos
5.
J Radiat Res ; 65(2): 194-204, 2024 Mar 22.
Artigo em Inglês | MEDLINE | ID: mdl-38264835

RESUMO

Enterogenic infection is a common complication for patients with radiation injury and requires efficient therapeutics in the clinic. Herein, we evaluated the promising drug candidate T7E21RHD5, which is a peptide derived from intestinal Paneth cell-secreted human defensin 5. Oral administration of this peptide alleviated the diarrhea symptoms of mice that received total abdominal irradiation (TAI, γ-ray, 12 Gy) and improved survival. Pathologic analysis revealed that T7E21RHD5 elicited an obvious mitigation of ionizing radiation (IR)-induced epithelial damage and ameliorated the reduction in the levels of claudin, zonula occluden 1 and occludin, three tight junction proteins in the ileum. Additionally, T7E21RHD5 regulated the gut microbiota in TAI mice by remodeling ß diversity, manifested as a reversal of the inverted proportion of Bacteroidota to Firmicutes caused by IR. T7E21RHD5 treatment also decreased the abundance of pathogenic Escherichia-Shigella but significantly increased the levels of Alloprevotella and Prevotellaceae_NK3B31, two short-chain fatty acid-producing bacterial genera in the gut. Accordingly, the translocation of enterobacteria and lipopolysaccharide to the blood, as well as the infectious inflammatory responses in the intestine after TAI, was all suppressed by T7E21RHD5 administration. Hence, this versatile antimicrobial peptide possesses promising application prospects in the treatment of IR-induced enterogenic infection.


Assuntos
Defensinas , Peptídeos , Humanos , Camundongos , Animais , Raios gama/efeitos adversos
6.
Poult Sci ; 103(1): 103175, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38029604

RESUMO

Poultry production is an important agricultural sector for human food worldwide. Chicks after hatch often face health problems leading to economic losses that are deleterious for breeders. Avian defensin 2 (AvBD2) is a prominent host defense peptide of the intestinal mucosa of cecum and is involved in the resistance of poultry to bacterial pathogens. This peptide could thus represent an innate immunity marker of robustness of birds. To test this hypothesis by comparing fast-growing and slow-growing lines in different conditions of breeding, the chick's cecal AvBD2 content was analyzed according to animal quality and immunity indicators. Chick's cecal tissue sections labeled by immunohistochemistry with newly developed specific antibodies revealed the localization of AvBD2 in the mucosa with high individual variability, without showing differences attributable to quality indicators, but interestingly showing inverse correlation with seric IgM levels in the fast-growing line. The availability of our anti-AvBD2 antibodies to the scientific community opens perspectives to identify the cellular sources of this defensin in the cecal mucosa and to investigate the organization and function of innate immune arsenal of birds.


Assuntos
Galinhas , Doenças das Aves Domésticas , Animais , Humanos , Imunidade Inata , Mucosa Intestinal/microbiologia , Bactérias , Defensinas , Ceco/microbiologia , Doenças das Aves Domésticas/microbiologia
7.
Int Immunopharmacol ; 127: 111383, 2024 Jan 25.
Artigo em Inglês | MEDLINE | ID: mdl-38118315

RESUMO

Tuberculosis (TB) is a serious airborne communicable disease caused by organisms of the Mycobacterium tuberculosis (Mtb) complex. Although the standard treatment antimicrobials, including isoniazid, rifampicin, pyrazinamide, and ethambutol, have made great progress in the treatment of TB, problems including the rising incidence of multidrug-resistant tuberculosis (MDR-TB) and extensively drug-resistant tuberculosis (XDR-TB), the severe toxicity and side effects of antimicrobials, and the low immunity of TB patients have become the bottlenecks of the current TB treatments. Therefore, both safe and effective new strategies to prevent and treat TB have become a top priority. As a subfamily of cationic antimicrobial peptides, defensins are rich in cysteine and play a vital role in resisting the invasion of microorganisms and regulating the immune response. Inspired by studies on the roles of defensins in host defence, we describe their research history and then review their structural features and antimicrobial mechanisms, specifically for fighting Mtb in detail. Finally, we discuss the clinical relevance, therapeutic potential, and potential challenges of defensins in anti-TB therapy. We further debate the possible solutions of the current application of defensins to provide new insights for eliminating Mtb.


Assuntos
Tuberculose Extensivamente Resistente a Medicamentos , Mycobacterium tuberculosis , Tuberculose Resistente a Múltiplos Medicamentos , Humanos , Antituberculosos/farmacologia , Antituberculosos/uso terapêutico , Tuberculose Resistente a Múltiplos Medicamentos/tratamento farmacológico , Tuberculose Resistente a Múltiplos Medicamentos/microbiologia , Tuberculose Extensivamente Resistente a Medicamentos/tratamento farmacológico , Tuberculose Extensivamente Resistente a Medicamentos/epidemiologia , Tuberculose Extensivamente Resistente a Medicamentos/microbiologia , Defensinas/uso terapêutico , Defensinas/farmacologia
8.
Mol Plant ; 17(2): 312-324, 2024 02 05.
Artigo em Inglês | MEDLINE | ID: mdl-38160253

RESUMO

Defensin-like proteins are conserved in multicellular organisms and contribute to innate immune responses against fungal pathogens. In rice, defensins play a novel role in regulating cadmium (Cd) efflux from the cytosol. However, whether the antifungal activity of defensins correlates with Cd-efflux function remains unknown. In this study, we isolated an endophytic Fusarium, designed Fo10, by a comparative microbiome analysis of rice plants grown in a paddy contaminated with Cd. Fo10 is tolerant to high levels of Cd, but is sensitive to the defensin-like protein OsCAL1, which mediates Cd efflux to the apoplast. We found that Fo10 symbiosis in rice is regulated by OsCAL1 dynamics, and Fo10 coordinates multiple plant processes, including Cd uptake, vacuolar sequestration, efflux to the environment, and formation of Fe plaques in the rhizosphere. These processes are dependent on the salicylic acid signaling pathway to keep Cd levels low in the cytosol of rice cells and to decrease Cd levels in rice grains without any yield penalty. Fo10 also plays a role in Cd tolerance in the poaceous crop maize and wheat, but has no observed effects in the eudicot plants Arabidopsis and tomato. Taken together, these findings provide insights into the mechanistic basis underlying how a fungal endophyte and host plant interact to control Cd accumulation in host plants by adapting defense responses to promote the establishment of a symbiosis that permits adaptation to high-Cd environments.


Assuntos
Oryza , Poluentes do Solo , Cádmio/metabolismo , Oryza/metabolismo , Poluentes do Solo/análise , Defensinas/metabolismo , Fungos , Solo
9.
Eur Rev Med Pharmacol Sci ; 27(22): 11093-11102, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-38039040

RESUMO

OBJECTIVE: The aim of the preliminary pilot single-center retrospective cross-sectional study was to analyze and compare the presence of non-secretory salivary inflammatory biomarkers in pediatric patients with West syndrome, Noonan syndrome, and a healthy control group. PATIENTS AND METHODS: A total of 60 saliva samples were collected during dental check-ups. The saliva samples collected were analyzed by liquid chromatography. The results were analyzed with a t-test, and the statistical significance was given by a p-value lower than 0.05. RESULTS: We found statistical significance for defensin α1 (p=0.006) and thymosin ß4 (p=0.025) in the Noonan syndrome. In the West syndrome, only the defensin α1 had a statistically significant difference with the other groups (p=0.022). Proteomic analysis revealed an overexpression of peptides related to the innate (thymosin ß4) and acquired (defensin α1, α3) immunity. CONCLUSIONS: West and Noonan's syndromes showed the overexpression of molecular biomarkers involved in the pathogenesis of chronic periodontitis. The inflammatory status is triggered and amplified by the abnormal overgrowth of gingival tissues, the amplified release of proinflammatory cytokines from the immune cells, and the poor cooperation in maintaining adequate oral hygiene.


Assuntos
Síndrome de Noonan , Espasmos Infantis , Humanos , Criança , Estudos Retrospectivos , Proteômica , Estudos Transversais , Saliva/química , Biomarcadores/análise , Defensinas/análise
10.
Clin Oral Investig ; 28(1): 53, 2023 Dec 29.
Artigo em Inglês | MEDLINE | ID: mdl-38157054

RESUMO

OBJECTIVES: This in vitro study aimed to modify TLR-2-mediated effects on the paracrine, proliferative, and differentiation potentials of human dental pulp-derived cells using histone acetyltransferase (HAT) and histone deacetylase (HDAC) inhibitors. MATERIALS AND METHODS: Cell viability was assessed using the XTT assay. Cells were either treated with 10 µg/ml Pam3CSK4 only, or pre-treated with valproic acid (VPA) (3 mM), trichostatin A (TSA) (3 µM), and MG-149 (3 µM) for a total of 4 h and 24 h. Control groups included unstimulated cells and cells incubated with inhibitors solvents only. Transcript levels for NANOG, OCT3-4, FGF-1 and 2, NGF, VEGF, COL-1A1, TLR-2, hßD-2 and 3, BMP-2, DSPP, and ALP were assessed through qPCR. RESULTS: After 24 h, TSA pre-treatment significantly upregulated the defensins and maintained the elevated pro-inflammatory cytokines, but significantly reduced healing and differentiation genes. VPA significantly upregulated the pro-inflammatory cytokine levels, while MG-149 significantly downregulated them. Pluripotency genes were not significantly affected by any regimen. CONCLUSIONS: At the attempted concentrations, TSA upregulated the defensins gene expression levels, and MG-149 exerted a remarkable anti-inflammatory effect; therefore, they could favorably impact the immunological profile of hDPCs. CLINICAL RELEVANCE: Targeting hDPC nuclear function could be a promising option in the scope of the biological management of inflammatory pulp diseases.


Assuntos
Inibidores de Histona Desacetilases , Receptor 2 Toll-Like , Humanos , Inibidores de Histona Desacetilases/farmacologia , Inibidores de Histona Desacetilases/metabolismo , Receptor 2 Toll-Like/metabolismo , Polpa Dentária , Histona Acetiltransferases/metabolismo , Histona Acetiltransferases/farmacologia , Ácido Valproico/metabolismo , Ácido Valproico/farmacologia , Histona Desacetilases/metabolismo , Histona Desacetilases/farmacologia , Defensinas/metabolismo , Defensinas/farmacologia
11.
Front Immunol ; 14: 1275845, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37915582

RESUMO

Rationale: COPD is characterized by chronic airway inflammation, small airways changes, with disappearance and obstruction, and also distal/alveolar destruction (emphysema). The chronology by which these three features evolve with altered mucosal immunity remains elusive. This study assessed the mucosal immune defense in human control and end-stage COPD lungs, by detailed microCT and RNA transcriptomic analysis of diversely affected zones. Methods: In 11 control (non-used donors) and 11 COPD (end-stage) explant frozen lungs, 4 cylinders/cores were processed per lung for microCT and tissue transcriptomics. MicroCT was used to quantify tissue percentage and alveolar surface density to classify the COPD cores in mild, moderate and severe alveolar destruction groups, as well as to quantify terminal bronchioles in each group. Transcriptomics of each core assessed fold changes in innate and adaptive cells and pathway enrichment score between control and COPD cores. Immunostainings of immune cells were performed for validation. Results: In mildly affected zones, decreased defensins and increased mucus production were observed, along CD8+ T cell accumulation and activation of the IgA pathway. In more severely affected zones, CD68+ myeloid antigen-presenting cells, CD4+ T cells and B cells, as well as MHCII and IgA pathway genes were upregulated. In contrast, terminal bronchioles were decreased in all COPD cores. Conclusion: Spatial investigation of end-stage COPD lungs show that mucosal defense dysregulation with decreased defensins and increased mucus and IgA responses, start concomitantly with CD8+ T-cell accumulation in mild emphysema zones, where terminal bronchioles are already decreased. In contrast, adaptive Th and B cell activation is observed in areas with more advanced tissue destruction. This study suggests that in COPD innate immune alterations occur early in the tissue destruction process, which affects both the alveoli and the terminal bronchioles, before the onset of an adaptive immune response.


Assuntos
Enfisema , Doença Pulmonar Obstrutiva Crônica , Enfisema Pulmonar , Humanos , Inflamação , Defensinas , Imunoglobulina A
12.
J Reprod Immunol ; 160: 104167, 2023 12.
Artigo em Inglês | MEDLINE | ID: mdl-37952294

RESUMO

Chronic endometritis has a high incidence in infertile women, which is caused by endometrial microbiome infection. In response to microbial infection, the role of defensins during chronic endometritis need explored. Besides, the expression of estrogen and its receptors vary in different menstrual cycles, but their roles in chronic endometritis are still unclear. In this study, we used the human endometrial tissues to examine the expression of antimicrobial peptides (AMPs) α-defensin hNP-1 and ß-defensins hBD-1, hBD-2, hBD-3, hBD-4 and LCN2. We found the expression of hBD-1 and LCN2 were downregulated in endometritis tissues, while the expressions of hBD-2, hBD-3, hBD-4, hNP-1, and estrogen and ERα were upregulated in chronic endometritis tissues compared to normal tissues. The expression and phosphorylation of STING, which is a crucial mediator of mammalian innate immunity in response to pathogens, was regulated with the treatment of ERα inhibitor raloxifene (Rx). Furthermore, using with the estrogen receptor inhibitor Rx and STING inhibitor H-151 significantly decreases the LCN2 expression. Taken together, these results suggested ERα was upregulated to modulate STING expression inducing LCN2 antimicrobial peptide expression to modulate the mucosal immunity during chronic endometritis.


Assuntos
Endometrite , Infertilidade Feminina , Animais , Feminino , Humanos , Defensinas/genética , Defensinas/metabolismo , Regulação para Baixo , Receptor alfa de Estrogênio/metabolismo , Estrogênios , Lipocalina-2/metabolismo , Mamíferos , Receptores de Estrogênio/metabolismo
13.
Facial Plast Surg Clin North Am ; 31(4): 535-546, 2023 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-37806687

RESUMO

Topical defensins have recently gained attention as agents to improve skin composition. This study aimed to aggregate and synthesize studies in the literature assessing the effects of topical defensins on skin composition in the context of its ability to combat signs of aging.


Assuntos
Envelhecimento da Pele , Pele , Humanos , Defensinas
14.
Signal Transduct Target Ther ; 8(1): 300, 2023 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-37574471

RESUMO

As a family of cationic host defense peptides, defensins are mainly synthesized by Paneth cells, neutrophils, and epithelial cells, contributing to host defense. Their biological functions in innate immunity, as well as their structure and activity relationships, along with their mechanisms of action and therapeutic potential, have been of great interest in recent years. To highlight the key research into the role of defensins in human and animal health, we first describe their research history, structural features, evolution, and antimicrobial mechanisms. Next, we cover the role of defensins in immune homeostasis, chemotaxis, mucosal barrier function, gut microbiota regulation, intestinal development and regulation of cell death. Further, we discuss their clinical relevance and therapeutic potential in various diseases, including infectious disease, inflammatory bowel disease, diabetes and obesity, chronic inflammatory lung disease, periodontitis and cancer. Finally, we summarize the current knowledge regarding the nutrient-dependent regulation of defensins, including fatty acids, amino acids, microelements, plant extracts, and probiotics, while considering the clinical application of such regulation. Together, the review summarizes the various biological functions, mechanism of actions and potential clinical significance of defensins, along with the challenges in developing defensins-based therapy, thus providing crucial insights into their biology and potential clinical utility.


Assuntos
Doenças Inflamatórias Intestinais , Celulas de Paneth , Animais , Humanos , Celulas de Paneth/metabolismo , Doenças Inflamatórias Intestinais/metabolismo , Defensinas/genética , Defensinas/metabolismo
15.
Pestic Biochem Physiol ; 194: 105511, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37532327

RESUMO

Pine wilt disease is a devastating disease of pine caused by the pine wood nematode (PWN) Bursaphelenchus xylophilus. Long-term use of chemical nematicides leads to the development of resistance in nematodes and harms the environment. Evaluations for green environmental protection agents, identified the antibacterial peptide, MaltDef1, from Monochamus alternatus which had nematicidal effect. We studied its nematicidal activity and action against PWN. In this study, the antibacterial peptide S-defensin was synthesized from M. alternatus. The results showed that S-defensin caused mortality to the PWN, causing shrinkage, pore, cell membrane dissolution and muscle atrophy. In addition, PWN reproduction was also affected by S-defensin; it decreased in a concentration dependent manner with increasing treatment concentration. By contrast, reactive oxygen species (ROS) in vivo increased in a concentration-dependent manner. We applied transcriptome to analyze the changes in gene expressions in S-defensin treated PWN, and found that the most significantly enriched pathway was the ERK/MAPK signaling pathway. RNAi was used to validate the functions of four differential genes (Let-23, Let-60, Mek-2 and Lin-1) in this pathway. The results showed that knockdown of these genes significantly decreased the survival rate and reproductive yield of, and also increased ROS in PWN. The antibacterial peptide S-defensin had a significant inhibitory effect on the survival and reproduction of PWN, shown by cell membrane damage and intracellular biological oxidative stress via regulating the ERK/MAPK signaling pathway. This indicates that S-defensin has a target in B. xylophilus, against which new green target pesticides can be developed.


Assuntos
Besouros , Nematoides , Pinus , Tylenchida , Animais , Espécies Reativas de Oxigênio , Doenças das Plantas , Estresse Oxidativo , Antinematódeos/farmacologia , Transdução de Sinais , Reprodução , Tylenchida/genética , Defensinas
16.
Parasit Vectors ; 16(1): 183, 2023 Jun 06.
Artigo em Inglês | MEDLINE | ID: mdl-37280715

RESUMO

BACKGROUND: The body and head lice of humans are conspecific, but only the body louse functions as a vector to transmit bacterial pathogens such as Bartonella quintana. Both louse subspecies have only two antimicrobial peptides, defensin 1 and defensin 2. Consequently, any differences in the molecular and functional properties of these two louse subspecies may be responsible for the differential vector competence between them. METHODS: To elucidate the molecular basis of vector competence, we compared differences in the structural properties and transcription factor/microRNA binding sites of the two defensins in body and head lice. Antimicrobial activity spectra were also investigated using recombinant louse defensins expressed via baculovirus. RESULTS: The full-length amino acid sequences of defensin 1 were identical in both subspecies, whereas the two amino acid residues in defensin 2 were different between the two subspecies. Recombinant louse defensins showed antimicrobial activities only against the representative Gram-positive Staphylococcus aureus but not against either Gram-negative Escherichia coli or the yeast Candida albicans. However, they did show considerable activity against B. quintana, with body louse defensin 2 being significantly less potent than head louse defensin 2. Regulatory sequence analysis revealed that the gene units of both defensin 1 and defensin 2 in body lice possess decreased numbers of transcription factor-binding sites but increased numbers of microRNA binding sites, suggesting relatively lower transcription activities of body louse defensins. CONCLUSIONS: The significantly lower antibacterial activities of defensin 2 along with the reduced probability of defensin expression in body lice likely contribute to the relaxed immune response to B. quintana proliferation and viability, resulting in higher vector competence of body lice compared to head lice.


Assuntos
Anti-Infecciosos , Bartonella quintana , Infestações por Piolhos , MicroRNAs , Pediculus , Animais , Humanos , Pediculus/genética , Pediculus/microbiologia , Bartonella quintana/genética , Infestações por Piolhos/microbiologia , MicroRNAs/genética , Fatores de Transcrição/genética , Defensinas/genética , Defensinas/farmacologia
17.
J Exp Bot ; 74(17): 5374-5393, 2023 09 13.
Artigo em Inglês | MEDLINE | ID: mdl-37326591

RESUMO

Ectopic expression of defensins in plants correlates with their increased capacity to withstand abiotic and biotic stresses. This applies to Arabidopsis thaliana, where some of the seven members of the PLANT DEFENSIN 1 family (AtPDF1) are recognised to improve plant responses to necrotrophic pathogens and increase seedling tolerance to excess zinc (Zn). However, few studies have explored the effects of decreased endogenous defensin expression on these stress responses. Here, we carried out an extensive physiological and biochemical comparative characterization of (i) novel artificial microRNA (amiRNA) lines silenced for the five most similar AtPDF1s, and (ii) a double null mutant for the two most distant AtPDF1s. Silencing of five AtPDF1 genes was specifically associated with increased aboveground dry mass production in mature plants under excess Zn conditions, and with increased plant tolerance to different pathogens - a fungus, an oomycete and a bacterium, while the double mutant behaved similarly to the wild type. These unexpected results challenge the current paradigm describing the role of PDFs in plant stress responses. Additional roles of endogenous plant defensins are discussed, opening new perspectives for their functions.


Assuntos
Proteínas de Arabidopsis , Arabidopsis , Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Estresse Fisiológico/genética , Zinco/metabolismo , Defensinas/genética , Defensinas/metabolismo , Defensinas/farmacologia , Regulação da Expressão Gênica de Plantas , Doenças das Plantas/genética
18.
Microbiol Spectr ; 11(4): e0077723, 2023 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-37260399

RESUMO

Mycobacterium abscessus, an intracellular nontuberculous mycobacterium, is considered the most pathogenic species among the group of rapidly growing mycobacteria. The resistance of M. abscessus to the host innate response contributes to its pathogenicity in addition to several virulence factors. We have recently shown in Drosophila that antimicrobial peptides (AMPs), whose production is induced by M. abscessus, are unable to control mycobacterial infection. This could be due to their inability to kill mycobacteria and/or the hidden location of the pathogen in phagocytic cells. Here, we demonstrate that the rapid internalization of M. abscessus by Drosophila macrophages allows it to escape the AMP-mediated humoral response. By depleting phagocytes in AMP-deficient flies, we found that several AMPs were required for the control of extracellular M. abscessus. This was confirmed in the Tep4 opsonin-deficient flies, which we show can better control M. abscessus growth and have increased survival through overproduction of some AMPs, including Defensin. Furthermore, Defensin alone was sufficient to kill extracellular M. abscessus both in vitro and in vivo and control its infection. Collectively, our data support that Tep4-mediated opsonization of M. abscessus allows its escape and resistance toward the Defensin bactericidal action in Drosophila. IMPORTANCE Mycobacterium abscessus, an opportunistic pathogen in cystic fibrosis patients, is the most pathogenic species among the fast-growing mycobacteria. How M. abscessus resists the host innate response before establishing an infection remains unclear. Using Drosophila, we have recently demonstrated that M. abscessus resists the host innate response by surviving the cytotoxic lysis of the infected phagocytes and the induced antimicrobial peptides (AMPs), including Defensin. In this work, we demonstrate that M. abscessus resists the latter response by being rapidly internalized by Drosophila phagocytes. Indeed, by combining in vivo and in vitro approaches, we show that Defensin is able to control extracellular M. abscessus infection through a direct bactericidal action. In conclusion, we report that M. abscessus escapes the host AMP-mediated humoral response by taking advantage of its internalization by the phagocytes.


Assuntos
Infecções por Mycobacterium não Tuberculosas , Mycobacterium abscessus , Mycobacterium , Animais , Drosophila , Opsonização , Peptídeos Antimicrobianos , Defensinas/farmacologia , Infecções por Mycobacterium não Tuberculosas/microbiologia , Antibacterianos/farmacologia
19.
Int Immunopharmacol ; 121: 110500, 2023 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-37352569

RESUMO

Although multiple vaccines have been developed against infectious diseases, the rapid emergence of new pathogens develops an urgent need for novel strategies to combat infectious diseases. Antimicrobial peptides (AMPs) are excellent agents to fight against infectious diseases having unique multiple mechanisms of action against various pathogens. Apart from the direct applications, AMPs can also be developed as subunit vaccines or could be used as a highly immunogenic carrier protein with highly antigenic but non-immunogenic antigens. Here in the present study, we have identified a novel defensin-like bacteriocin, laterosporulin25 (LS25) upon genome mining of Brevibacillus laterosporus DSM25, a probiotic bacterial strain. By using immunoinformatic tools, we have studied the immunogenic and physiochemical properties of LS25. LS25 is characterized as defensin-like bacteriocin, having 51 amino acids and a molecular weight of 5862.7 Da. The modeled tertiary structure of LS25 is docked with TLR3 and TLR4-MD2 complex to confirm the facilitation of induced immune response that is further validated using molecular dynamics simulations and In-silico immune stimulations. Overall, detailed immunoinformatics analysis suggested LS25 as a potential candidate to be used as an adjuvant or carrier protein for subunit vaccine development, however, further in-vitro and in-vivo experiments are essential to validate its potential.


Assuntos
Bacteriocinas , Bacteriocinas/química , Bacteriocinas/farmacologia , Defensinas/farmacologia , Proteínas de Transporte , Vacinas de Subunidades , Epitopos de Linfócito T , Simulação de Acoplamento Molecular , Biologia Computacional , Epitopos de Linfócito B
20.
Transgenic Res ; 32(3): 223-233, 2023 06.
Artigo em Inglês | MEDLINE | ID: mdl-37131050

RESUMO

Plant defensins are a potential tool in crop improvement programs through biotechnology. Their antifungal action makes them attractive molecules for the production of transgenic plants. Information is currently lacking on what happens to the expression of defense genes in transgenic plants that overexpress a defensin. Here we show the relative expression of four defense-related genes: Mn-sod, PAL1, aos1 and HPL evaluated in two transgenic soybean events (Def1 and Def17) constitutively expressing the NmDef02 defensin gene from Nicotiana megalosiphon. The expression of these defense genes showed a differential profile in the transgenic events, with the increased expression of the aos1 gene and the repression of the Mn-sod gene in both events, when compared to the non-transgenic control. Furthermore, the expression of the PAL1 gene only increased in the Def17 event. The results indicate that although there were some changes in the expression of defense genes in transgenic plants overexpressing the defensin NmDef02; the morphoagronomic parameters evaluated were similar to the non-transgenic control. Understanding the molecular changes that occur in these transgenic plants could be of interest in the short, medium and long term.


Assuntos
Superóxido Dismutase , /genética , Superóxido Dismutase/genética , Plantas Geneticamente Modificadas/metabolismo , /metabolismo , Defensinas/genética , Regulação da Expressão Gênica de Plantas
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