Antimicrobial Peptides Research Articles

Recent Advancement in Novel Wound Healing Therapies by Using Antimicrobial Peptides Derived from Humans and Amphibians.

The skin is the biggest organ in the human body. It is the first line of protection against invading pathogens and the starting point for the immune system. The focus of this review is on the use of amphibian-derived peptides and antimicrobial peptides (AMPs) in the treatment of wound healing. When skin is injured, a chain reaction begins that includes inflammation, the formation of new tissue, and remodelling of existing tissue to aid in the healing process. Collaborating with non-immune cells, resident and recruited immune cells in the skin remove foreign invaders and debris, then direct the repair and regeneration of injured host tissues. Restoration of normal structure and function requires the healing of damaged tissues. However, a major issue that slows wound healing is infection. AMPs are just one type of host-defense chemicals that have developed in multicellular animals to regulate the immune response and limit microbial proliferation in response to various types of biological or physical stress. Therefore, peptides isolated from amphibians represent novel therapeutic tools and approaches for regenerating damaged skin. Peptides that speed up the healing process could be used as therapeutic lead molecules in future research into novel drugs. AMPs and amphibian-derived peptides may be endogenous mediators of wound healing and treat non-life-threatening skin and epithelial lesions. Thus, the present article was drafted with to incorporate different peptides used in wound healing, their method of preparation and routes of administration.

Lung antimicrobial proteins and peptides: from host defense to therapeutic strategies.

Representing severe morbidity and mortality globally, respiratory infections associated with chronic respiratory diseases, including complicated pneumonia, asthma, interstitial lung disease, and chronic obstructive pulmonary disease, are a major public health concern. Lung health and the prevention of pulmonary disease rely on the mechanisms of airway surface fluid secretion, mucociliary clearance, and adequate immune response to eradicate inhaled pathogens and particulate matter from the environment. The antimicrobial proteins and peptides contribute to maintaining an antimicrobial milieu in human lungs to eliminate pathogens and prevent them from causing pulmonary diseases. The predominant antimicrobial molecules of the lung environment include human α- and β-defensins and cathelicidins, among numerous other host defense molecules with antimicrobial and antibiofilm activity such as PLUNC (palate, lung, and nasal epithelium clone) family proteins, elafin, collectins, lactoferrin, lysozymes, mucins, secretory leukocyte proteinase inhibitor, surfactant proteins SP-A and SP-D, and RNases. It has been demonstrated that changes in antimicrobial molecule expression levels are associated with regulating inflammation, potentiating exacerbations, pathological changes, and modifications in chronic lung disease severity. Antimicrobial molecules also display roles in both anticancer and tumorigenic effects. Lung antimicrobial proteins and peptides are promising alternative therapeutics for treating and preventing multidrug-resistant bacterial infections and anticancer therapies.

Theranostic Nanomaterials to Overcome the Challenges in Peptide-based Cancer Therapy

: Globally, the number of cancer cases and death rates are increasing, making it necessary to develop new and improved medications for the treatment of cancer.Owing to a broad range of physio-chemical properties, Antimicrobial Peptides (AMPs) possessing tumoricidal properties and Anticancer Peptides (ACPs) are promising alternatives for enhanced cancer therapy. Recently, biopharmaceuticals have changed the rules of radiation therapy and chemotherapy by introducing peptide therapy for cancer treatments. However, several limitations obstruct the clinical efficacy of peptide-based cancer therapies, which include limited target specificity, oral intake, and half-life payloads. The integration of theranostic nanomaterials could be facilitated as a transformative strategy to address these challenges and enhance the potential of peptide-based cancer therapy. Increasing applications of recent times of peptide-nano hybrids have addressed the crucial issues related to conventional peptide-based drug therapy by enhancing the druggability. This review aims to explore the impact of nano-formulated peptides as an anticancer agent, highlighting the involvement of nanotechnology as an enabling tool.

Synthesis and Antibacterial Evaluation of Novel Small-Molecule Antibacterials of a Reduced Acridine Structure in S. aureus Strains Including MRSA.

The increasing antibacterial drug resistance remains a threat to global health with increasing mortality and morbidity. There is an urgent need to find novel antibacterials and develop alternative strategies to combat the increasing antibacterial drug resistance. <P> </P> Objective: We aimed to synthesize novel small-molecule antibacterials to evaluate the structuredependent antibacterial compound activities against S. aureus and MRSA. <P> </P> Method: Compounds were synthesized by primary N-alkylation to form alkyl acridinium salts that were further functionalized with substituted phenyl residues and finally purified by column chromatography. The antibacterial growth inhibition activity was determined as MIC value. <P> </P> Results: The substituent effects on the determined antibacterial growth inhibitory properties have been discussed. <P> </P> Conclusion: The best activities have been found for compounds with methoxy functions, exceeding the activities of reported novel antibacterial peptides. The compounds have also shown antibacterial drug-enhancing effects, which have been manifested as a reduction in the MIC values of the used antibiotics.

Protective Effects of Antimicrobial Peptide Microcin J25 (MccJ25) Isolated From Escherichia coli Against Breast Cancer Cells

ABSTRACTMicrocins are antimicrobial peptides (AMPs) with low molecular weight, which are produced by Enterobacterales and have broad‐spectrum antibacterial activity. Alternative approaches like AMPs could help conventional anticancer treatments to fight malignant cells. The present study endeavors to examine the antitumor activity of microcins isolated from different Enterobacterales strains. In total, 120 Enterobacterales isolates were examined after identification. Subsequently, the bacteria were subjected to an agar diffusion test to assess their antibacterial efficacy. Positive isolates were further examined for the presence of Mccj25 using PCR. The cytotoxic effects of isolates harboring the microcin gene were explored using quantitative real‐time PCR (RT‐qPCR) and the MTT test on breast cancer cells. In addition, the expression levels of BCL2 and STAT3 genes were evaluated, and apoptosis was quantified using flow cytometry. The repair rate of normal cells was determined using a scratch assay. The findings obtained from the phenotypic and biochemical assays have duly verified and established the categorization of the Enterobacterales. After conducting the agar diffusion test, a total of 25 isolates of Escherichia coli and Klebsiella pneumoniae displaying inhibition zones were chosen as suitable specimens possessing AMPs. The analysis conducted on the expression of the Mccj25 gene within the aforementioned isolates indicated that Isolate 83 exhibited significant expression of the Mccj25 gene. The extract obtained from this isolate on the breast cancer cell line exhibited the most significant degree of toxicity after 48 h. Furthermore, the treatment of breast cancer cells with Isolate 83 showed that the rate of apoptosis was about 86%, and the expression of BCL2 and STAT3 genes decreased. Contrarily, it potentiated the reparative ability of nontumoral fibroblasts, supporting the in vitro safety toward normal cells and, at the same time, the selectivity against malignant ones. In summary, our results highlighted a significant growth suppression of breast cancer cells with an escalated rate of cellular demise via the apoptosis pathway.

Application of self-assembled antibacterial nanofiber loaded oriented artificial skin in infected diabetic-related wound regeneration

Diabetic patients develop wounds that exhibit delayed healing, prolonged inflammatory responses, and slower epithelialization kinetics compared to non-diabetic patients. Diabetic foot ulcers(DFUs) affect approximately 18.6 million people worldwide. The presence of a high glucose microenvironment in DFUs results in the significant accumulation of bacterial infection and advanced glycation end products (AGEs). To solve this, a self-assemble antibacterial nanofiber(ANF) loaded oriential artificial skin (ANF@OAS) was introduced in this research, which is consisted of L/D-phenylalanine derivatives coupled the natural antimicrobial peptides. The ANF@OAS can effectively reduce AGEs production and suppress multiple resistant bacteria. Additionally, the ANF@OAS can suppress infection and stimulate wound healing in infected diabetic mice.

DEFB119 stratifies dysbiosis with distorted networks in the seminal microbiome associated with male infertility

Abstract Infertility is associated with the alteration of the seminal microbiome. However, the onset of dysbiosis remains controversial and the involvement of host factors remains elusive. This study investigates the alterations of the seminal microbiome in male infertility and examines the association and function of DEFB119, a reproductive-tract-specific host antimicrobial peptide, on the seminal microbiome and male fertility. While we observed comparable genera, diversity and evenness of bacterial communities, a marked decrease in the modularity of the metacommunities was observed in patients with abnormal spermiogram (n=57) as compared to the control (n=30). A marked elevation of DEFB119 was observed in a subpopulation of male-infertile patients (n=5). Elevated seminal DEFB119 was associated with a decrease in the observed genera, diversity and evenness of bacterial communities and further distortion of the metacommunities. Mediation analysis suggests the involvement of elevated DEFB119 and dysbiosis of the seminal microbiome in mediating the abnormalities in the spermiogram. Functional experiments showed that recombinant DEFB119 significantly decrease the progressive motility of sperm in patients with abnormal spermiogram. Moreover, DEFB119 demonstrated species-specific antimicrobial activity against common seminal and non-seminal species. Our work identifies an important host factor that mediates the host-microbiome interaction and stratifies the seminal microbiome associated with male infertility. These results may lead to a new diagnostic method for male infertility and regimens for formulating the microbiome in the reproductive tract and other organ systems.

Antimicrobial Peptides with Spermicidal Activity as New Contraceptive Agents: Killing Two Birds with One Stone

Abstract: Antimicrobial peptides (AMPs) have emerged as promising candidates for dual-action contraceptive agents, offering both spermicidal and antimicrobial properties. This perspective explores the potential of AMPs in developing novel contraceptive technologies, focusing on their application in condom coatings and vaginal formulations. AMPs exert their effects through membrane disruption mechanisms, targeting both microbial pathogens and sperm cells. Their broad-spectrum activity against various microorganisms, coupled with spermicidal effects, makes them ideal for multipurpose prevention technologies. The incorporation of AMPs into condoms could enhance barrier protection, while vaginal applications offer non-hormonal, on-demand contraceptive options. However, challenges, such as potential vaginal irritation, microbiome disruption, and the need for long-term safety studies, must be addressed. Future research should focus on optimizing AMP selectivity, developing stable formulations, and conducting comprehensive efficacy and safety trials. The dual-action nature of AMPs aligns with the growing demand for integrated approaches to sexual and reproductive health, potentially revolutionizing contraception and STI prevention. By addressing current challenges and leveraging the unique properties of AMPs, researchers can develop a new generation of contraceptive products that offer improved efficacy, safety, and user acceptability.

Antimicrobial Peptide Hydrogel with pH-Responsive and Controllable Drug Release Properties for the Efficient Treatment of Helicobacter pylori Infection.

Helicobacter pylori is the primary cause of gastric adenocarcinoma, which afflicts more than half of the world's population and seriously affects human health. However, achieving efficient treatment of H. pylori infection by effective drug delivery and bioavailability after oral administration remains a challenge due to the harsh microenvironment, short drug retention time, and physiological barriers in the stomach. Moreover, H. pylori has shown resistance to many clinical antibiotics. Antimicrobial peptides (AMPs) exhibit substantial therapeutic efficacy against H. pylori, while they are not likely to induce drug resistance, suggesting their potential utility for the treatment of diseases related to H. pylori. In this paper, we report the design and synthesis of an AMP (GE33) hydrogel with pH-responsive and controlled peptide release properties, in which the minimal inhibitory concentration of the AMP against H. pylori is as low as 1 μg/mL. GE33 self-assembles into a stable peptide hydrogel under neutral pH conditions but decomposes into monomers or oligomers under acidic conditions. Upon oral administration of the hydrogel, the acidic gastric environment would facilitate rapid release of active AMP molecules from the hydrogel and immediate targeting of H. pylori in the stomach wall. Additionally, the remaining peptide is protected in the hydrogel, extending its retention time in the stomach, so that persistent drug release is achieved. The controlled and sustained release manner of the active molecule GE33, which enhances drug bioavailability, along with its excellent bactericidal efficacy opens a great potential for treating H. pylori infection.

Recent Progress in Terrestrial Biota-Derived Anti-Biofilm Agents for Medical Applications

The terrestrial biota is a rich source of biologically active substances whose anti-biofilm potential is not studied enough. The aim of this review is to outline a variety of terrestrial sources of antimicrobial agents with the ability to inhibit different stages of biofilm development, expecting to give some ideas for their utilization in improved anti-biofilm treatments. It provides an update for the last 5 years on anti-biofilm plant products and derivatives, essential oils, antimicrobial peptides, biosurfactants, etc., that are promising candidates for providing novel alternative approaches to combating multidrug-resistant biofilm-associated infections. Based on the reduction in bacterial adhesion to material and cell surfaces, the anti-adhesion strategy appears interesting for the prevention of bacterial attachment in combating a broad range of mono- and multispecies bacterial biofilms. So far, few studies have been carried out in this direction. Anti-biofilm coatings made by or containing biologically active products from terrestrial biota have scarcely been studied although they are of significant interest for a reduction in infections associated with medical devices. Combination therapy with commercial antibiotics and natural products is accepted now as a promising base for future advances in anti-biofilm treatment. In vivo testing and clinical trials are necessary for clinical application.

Inducible antibacterial responses in macrophages.

Macrophages destroy bacteria and other microorganisms through phagocytosis-coupled antimicrobial responses, such as the generation of reactive oxygen species and the delivery of hydrolytic enzymes from lysosomes to the phagosome. However, many intracellular bacteria subvert these responses, escaping to other cellular compartments to survive and/or replicate. Such bacterial subversion strategies are countered by a range of additional direct antibacterial responses that are switched on by pattern-recognition receptors and/or host-derived cytokines and other factors, often through inducible gene expression and/or metabolic reprogramming. Our understanding of these inducible antibacterial defence strategies in macrophages is rapidly evolving. In this Review, we provide an overview of the broad repertoire of antibacterial responses that can be engaged in macrophages, including LC3-associated phagocytosis, metabolic reprogramming and antimicrobial metabolites, lipid droplets, guanylate-binding proteins, antimicrobial peptides, metal ion toxicity, nutrient depletion, autophagy and nitric oxide production. We also highlight key inducers, signalling pathways and transcription factors involved in driving these different antibacterial responses. Finally, we discuss how a detailed understanding of the molecular mechanisms of antibacterial responses in macrophages might be exploited for developing host-directed therapies to combat antibiotic-resistant bacterial infections.

Transcriptomic analysis reveals molecular insights into lactation dynamics in Jakhrana goat mammary gland

BackgroundGoat milk is gaining popularity as a superior alternative to bovine milk due to its closer resemblance to human milk. Understanding the molecular processes underlying lactation is crucial for improving milk quality and production in goats. However, the genetic mechanisms governing lactation in goats, particularly in indigenous breeds like the Jakhrana, remain largely unexplored.ResultsIn this study, we performed a comprehensive transcriptomic analysis of Jakhrana goat mammary glands during early and late lactation stages. We isolated milk somatic cells and conducted RNA sequencing, followed by transcript quantification and mapping against the ARS1.2 Capra hircus reference assembly. Our analysis identified differentially expressed genes (DEGs) and commonly expressed genes (CEGs) across the lactation phases. Early lactation showed enrichment of genes encoding antimicrobial peptides and lubrication proteins, while late lactation exhibited heightened expression of genes encoding major milk proteins. Additionally, DEG analysis revealed upregulation of pivotal genes, such as the ABC transporter gene MRP4, implicated in modulating milk composition and quality.ConclusionOur findings provide insights into the genetic mechanisms underlying lactation dynamics in the Jakhrana goat. Understanding these mechanisms could help in improving milk production and quality in goats, benefiting both the dairy industry and consumers.

Immunohistochemistry Study of Antimicrobial Peptides as a Future Diagnostic and Prognostic Tool for Periprosthetic Joint Infections

Immunohistochemistry Study of Antimicrobial Peptides as a Future Diagnostic and Prognostic Tool for Periprosthetic Joint Infections

Semantic search using protein large language models detects class II microcins in bacterial genomes.

Antibiotic resistance is becoming an increasingly serious problem in modern medicine, but the development pipeline for conventional antibiotics is not promising. Therefore, alternative approaches to combat bacterial infections are urgently needed. One such approach may be to employ naturally occurring antibacterial peptides produced by bacteria to kill competing bacteria. A promising class of such peptides are class II microcins. However, only a small number of class II microcins have been discovered to date, and the discovery of further such microcins has been hampered by their high sequence divergence and short length, which can cause sequence-based search methods to fail. Here, we demonstrate that a more robust method for microcin discovery can be built on the basis of a protein large language model, and we use this method to identify several putative novel class II microcins.

Enhancing tumor penetration: GSH-sensitive paclitaxel liposomes modified with Dermaseptin-PP

The dense structure of solid tumor tissues and the selective permeability of cell membranes impede the effective penetration of chemotherapeutic agent-loaded liposomes into tumors and their subsequent uptake by cells. Dermaseptin-PP, a cationic antimicrobial peptide, has demonstrated the ability to enhance the penetration and accumulation of drugs within solid tumors due to its unique membrane-breaking action. Based on this, we designed glutathione (GSH)-sensitive paclitaxel liposomes modified with Dermaseptin-PP. Dermaseptin-PP was modified through disulfide bonding, which could be broken at the tumor site due to high GSH levels. This cleavage resulted in the release of Dermaseptin-PP, thereby enhancing the permeability of the paclitaxel liposomes within the tumor. We found that the paclitaxel liposomes modified with Dermaseptin-PP were extensively distributed to the tumor site, and the Dermaseptin-PP modification significantly enhanced liposome penetration within the tumor. Our study significantly increased the anti-tumor efficacy of paclitaxel liposomes. Our study confirms that paclitaxel liposomes modified with Dermaseptin-PP is an effective anti-tumor therapy that enhances deep penetration into tumors. Additionally, this broadens the applications of cationic antimicrobial peptides.

Stabilization of hypoxia-inducible factor 1α and regulation of specific gut microbes by EGCG contribute to the alleviation of ileal barrier disorder and obesity.

Tea polyphenols have a regulatory effect on metabolic-related diseases, however, the underlying mechanism remains elusive. Our study aims to explore the dietary intervention effect of Epigallocatechin gallate (EGCG), the major polyphenol in green tea, on obesity and intestinal barrier disorders in mice fed a high-fat diet. By supplementing with 50 mg kg-1 EGCG, we observed a significant amelioration in body weight gain, fat accumulation, and liver dysfunction. Furthermore, EGCG modulated the HFD-induced metabolomic alterations. In particular, EGCG intervention restored the ileal barrier by enhancing the expression of tight junction proteins and antimicrobial peptides. At the mechanistic level, EGCG treatment stabilized hypoxia-inducible factor 1α (HIF1α) both in vitro and in vivo. Meanwhile, EGCG significantly increased the abundance of Dubosiella and Akkermansia, along with the elevated SCFA contents. These findings suggest that the ability of EGCG to stabilize HIF1α and regulate specific gut microbes is pivotal in mitigating ileal barrier dysfunction and obesity. Moreover, serum metabolomics revealed potential biomarkers following EGCG intervention. This study supports the intake of EGCG or green tea in obesity management and offers a novel perspective for investigating the metabolic regulatory mechanism of other dietary polyphenols.

Characterization of a marine endolysin LysVPB against Vibrio parahaemolyticus

Currently, there is an urgent to develop safe and environmentally friendly alternatives to antibiotics for combating Vibrio parahaemolyticus. Endolysins are considered promising antibacterial agents due to their desirable range of action and ability to deal with antibiotic-resistant bacteria. While numerous Vibrio phages have been identified, the research on their endolysins is still in its infancy. In this study, a novel endolysin called LysVPB was cloned and expressed in Pichia pastoris. Phylogenetic analysis revealed that LysVPB bears little resemblance to other known endolysins, highlighting its unique nature. Homology modeling identified a putative calcium-binding site in LysVPB. The recombinant LysVPB achieved a lytic activity of 64.8 U/mL and had a molecular weight of approximately 17 kDa. LysVPB exhibited enhanced efficacy at pH 9.0, with 60 % of its maximum activity observed within the broad pH range of 6.0–10.0. The catalytic efficiency of LysVPB peaked at 30 °C but significantly declined beyond 50 °C. Ba2+, Co2+, and Cu2+ showed inhibitory effects on the activity of LysVPB, while Ca2+ can boost it to 126.8 %. Furthermore, LysVPB exhibited satisfactory efficacy against strains of V. parahaemolyticus. LysVPB is an innovative phage lysin with good characteristics that are specific to certain hosts. The modular nature of LysVPB allows for efficient domain exchange with alternative lysins as antimicrobial components and fusion with antimicrobial peptides. This opens up possibilities for engineering chimeric lysins in a broader range of target hosts with high antimicrobial effectiveness and strong activity under physiological conditions.

Genome sequences of six lactic acid bacteria from artisanal cheese reveal biosynthetic gene clusters encoding antimicrobial compounds.

Lactic acid bacteria are valuable in the production of fermented foods and as sources of antimicrobial peptides (e.g., bacteriocins). The genomes of six lactic acid bacteria, isolated from artisanal cheeses, having biosynthetic gene clusters encoding antimicrobial compounds are reported. The six strains belong to the genera Lacticaseibacillus, Lactococcus, Leuconostoc, and Enterococcus.

Antimicrobial Functionalization of Surfaces by a Chimeric Adhesive Protein.

The main aim of this work is to account for the prevention and control of microbial growth on surfaces of interest in medical technology. Surface modification is often achieved by physiotherapy or chemical treatments that can involve time-consuming steps, hazardous reagents, and harsh conditions. One of the ways to overcome these drawbacks is the use of surface-active proteins such as hydrophobins. They can form stable protein layers on different surfaces, serving as anchoring points for other molecules of interest. The fungal hydrophobin Vmh2, already exploited for its adhesive ability, has been fused with the antimicrobial peptide GKY20, forming the chimeric protein used herein for functionalizing polystyrene (PS) and bacterial cellulose (BC). As a natural biomass, BC has multiple advantages, including biodegradability, low cost, renewability, high purity, and excellent mechanical properties. The chimeric protein has been proven to successfully adhere to both surfaces. A strong decrease in biofilm formation on PS and a good bactericidal effect of BC have been demonstrated. These findings provide evidence of an alternative strategy to obtain functional composites using a green, easy process.

Pneumolysin-responsive liposomal platform for selective treatment of Streptococcus pneumoniae.

The bacterium Streptococcus pneumoniae has become a leading cause of meningitis, sepsis, and bacterial pneumonia worldwide, with increased prevalence of antibiotic-resistant serotypes serving to exacerbate the issue. The main factor responsible for colonization and immune response escape in pneumococcal infections is the secreted molecule pneumolysin, which is a subset within a family of related toxins that form transmembrane pores in biological membranes through cholesterol recognition and binding. The conserved activity and structure of pneumolysin between all observed S. pneumoniae serotypes, along with its requirement for pathogenicity, has made this molecule an attractive target for vaccination, diagnostic, and sequestration platforms, but not yet as a facilitative agent for therapeutic treatment. Consequently, the present work aimed to examine the impact of liposomal cholesterol content for pneumolysin-induced release of the encapsulated antimicrobial peptide nisin. It was determined that a cholesterol content above 45mol% was necessary to facilitate interactions with both purified pneumolysin toxin and S. pneumoniae culture, demonstrated through enhanced nisin release and a reduction in hemolytic rates upon exposure of the toxin with cholesterol-rich vesicles. Antibacterial testing highlighted the ability of the developed platform to elicit a potent and specific bactericidal response in vitro against cultured S. pneumoniae when compared to a control strain, Staphylococcus epidermidis. It further improved viability of a fibroblast cell line upon S. pneumoniae challenge, outperforming free nisin via the synergistic impact of simultaneous bacterial clearance and pneumolysin neutralization. These findings collectively indicate that cholesterol-rich liposomes hold promise as a selective treatment platform against pneumococcal infections.