Association between host defence peptide IDR-1002 and ciprofloxacin: Effects on human dental pulp cells.

To evaluate the effects of the association of host defence peptide IDR-1002 and ciprofloxacin on human dental pulp cells (hDPSCs). hDPSCs were stimulated with ciprofloxacin and IDR-1002. Cell viability (by MTT assay), migration capacity (by scratch assay), production of inflammatory and anti-inflammatory mediators by hDPSCs (RT-PCR) and osteogenic differentiation (alizarin red staining) were evaluated. Phenotypic profile of hDPSCs demonstrated 97% for positive marked mesenchymal stem cell. Increased pulp cell migration and proliferation were observed after 24 and 48 h of exposure to IDR-1002 with ciprofloxacin. Mineral matrix formation by hDPSCs was observed of the association while its reduction was observed in the presence of peptide. After 24 h, the association between ciprofloxacin and IDR-1002 significantly downregulated TNFRSF-1, IL-1ß, IL-8, IL-6 and IL-10 gene expression (p ≤ 0.0001). The association between the IDR-1002 and ciprofloxacin showed favourable immunomodulatory potential, emerging as a promising option for pulp revascularisation processes.

Evaluating virulence features of Acinetobacter baumannii resistant to polymyxin B.

The increasing resistance to polymyxins in Acinetobacter baumannii has made it even more urgent to develop new treatments. Anti-virulence compounds have been researched as a new solution. Here, we evaluated the modification of virulence features of A. baumannii after acquiring resistance to polymyxin B. The results showed lineages attaining unstable resistance to polymyxin B, except for Ab7 (A. baumannii polymyxin B resistant lineage), which showed stable resistance without an associated fitness cost. Analysis of virulence by a murine sepsis model indicated diminished virulence in Ab7 (A. baumannii polymyxin B resistant lineage) compared with Ab0 (A. baumannii polymyxin B susceptible lineage). Similarly, downregulation of virulence genes was observed by qPCR at 1 and 3 h of growth. However, an increase in bauE, abaI, and pgAB expression was observed after 6 h of growth. Comparison analysis of Ab0, Ab7, and Pseudomonas aeruginosa suggested no biofilm formation by Ab7. In general, although a decrease in virulence was observed in Ab7 when compared with Ab0, some virulence feature that enables infection could be maintained. In light of this, virulence genes bauE, abaI, and pgAB showed a potential relevance in the maintenance of virulence in polymyxin B-resistant strains, making them promising anti-virulence targets.

Capping motifs in antimicrobial peptides and their relevance for improved biological activities.

N-capping (N-cap) and C-capping (C-cap) in biologically active peptides, including specific amino acids or unconventional group motifs, have been shown to modulate activity against pharmacological targets by interfering with the peptide's secondary structure, thus generating unusual scaffolds. The insertion of capping motifs in linear peptides has been shown to prevent peptide degradation by reducing its susceptibility to proteolytic cleavage, and the replacement of some functional groups by unusual groups in N- or C-capping regions in linear peptides has led to optimized peptide variants with improved secondary structure and enhanced activity. Furthermore, some essential amino acid residues that, when placed in antimicrobial peptide (AMP) capping regions, are capable of complexing metals such as Cu2+, Ni2+, and Zn2+, give rise to the family known as metallo-AMPs, which are capable of boosting antimicrobial efficacy, as well as other activities. Therefore, this review presents and discusses the different strategies for creating N- and C-cap motifs in AMPs, aiming at fine-tuning this class of antimicrobials.

Antiviral Activities of Mastoparan-L-Derived Peptides against Human Alphaherpesvirus 1.

Human alphaherpesvirus 1 (HSV-1) is a significantly widespread viral pathogen causing recurrent infections that are currently incurable despite available treatment protocols. Studies have highlighted the potential of antimicrobial peptides sourced from Vespula lewisii venom, particularly those belonging to the mastoparan family, as effective against HSV-1. This study aimed to demonstrate the antiviral properties of mastoparans, including mastoparan-L [I5, R8], mastoparan-MO, and [I5, R8] mastoparan, against HSV-1. Initially, Vero cell viability was assessed in the presence of these peptides, followed by the determination of antiviral activity, mechanism of action, and dose-response curves through plaque assays. Structural analyses via circular dichroism and nuclear magnetic resonance were conducted, along with evaluating membrane fluidity changes induced by [I5, R8] mastoparan using fluorescence-labeled lipid vesicles. Cytotoxic assays revealed high cell viability (>80%) at concentrations of 200 µg/mL for mastoparan-L and mastoparan-MO and 50 µg/mL for [I5, R8] mastoparan. Mastoparan-MO and [I5, R8] mastoparan exhibited over 80% HSV-1 inhibition, with up to 99% viral replication inhibition, particularly in the early infection stages. Structural analysis indicated an α-helical structure for [I5, R8] mastoparan, suggesting effective viral particle disruption before cell attachment. Mastoparans present promising prospects for HSV-1 infection control, although further investigation into their mechanisms is warranted.

Genetic basis of antibiotic resistance in bovine mastitis and its possible implications for human and ecological health.

Bovine mastitis is a mammary gland inflammation that can occur due to infectious pathogens, Staphylococcus aureus and Escherichia coli, which are, respectively, the most prevalent Gram-positive and Gram-negative bacteria associated with this disease. Currently, antibiotic treatment has become more complicated due to the presence of resistant pathogens. This review, therefore, aims to identify the most common resistance genes reported for these strains in the last four years. During the review, it was noted that blaZ, blaSHV, blaTEM, and blaampC are the most reported genes for S. aureus and E. coli, associated with drug inactivation, mainly ß-lactamases. They are characterized by generating bacterial resistance to ß-lactam antibiotics, the most common treatment in animal and human bacterial treatments (penicillins and cephalosporins, among others). Genes associated with efflux systems were also present in the two strains and included norA, tetA, tetC, and tetK, which generate resistance to macrolide and tetracycline antibiotics. Additionally, the effects of spreading resistance between animals and humans through direct contact (such as consumption of contaminated milk) or indirect contact (through environmental contamination) has been deeply discussed, emphasizing the importance of having adequate sanitation and antibiotic control and administration protocols.

Senotherapeutic Peptide 14 Suppresses Th1 and M1 Human T Cell and Monocyte Subsets In Vitro.

Inflammation contributes to the onset and exacerbation of numerous age-related diseases, often manifesting as a chronic condition during aging. Given that cellular senescence fosters local and systemic inflammation, senotherapeutic interventions could potentially aid in managing or even reducing inflammation. Here, we investigated the immunomodulatory effects of the senotherapeutic Peptide 14 (Pep 14) in human peripheral blood mononuclear cells (PBMCs), monocytes, and macrophages. We found that, despite failing to significantly influence T cell activation and proliferation, the peptide promoted a Th2/Treg gene expression and cytokine signature in PBMCs, characterized by increased expression of the transcription factors GATA3 and FOXP3, as well as the cytokines IL-4 and IL-10. These observations were partially confirmed through ELISA, in which we observed increased IL-10 release by resting and PHA-stimulated PBMCs. In monocytes from the U-937 cell line, Pep 14 induced apoptosis in lipopolysaccharide (LPS)-stimulated cells and upregulated IL-10 expression. Furthermore, Pep 14 prevented LPS-induced activation and promoted an M2-like polarization in U-937-derived macrophages, evidenced by decreased expression of M1 markers and increased expression of M2 markers. We also showed that the conditioned media from Pep 14-treated macrophages enhanced fibroblast migration, indicative of a functional M2 phenotype. Taken together, our findings suggest that Pep 14 modulates immune cell function towards an anti-inflammatory and regenerative phenotype, highlighting its potential as a therapeutic intervention to alleviate immunosenescence-associated dysregulation.

Just around the Corner: Advances in the Optimization of Yeasts and Filamentous Fungi for Lactic Acid Production.

Lactic acid (LA) production has seen significant progress over the past ten years. LA has seen increased economic importance due to its broadening use in different sectors such as the food, medicine, polymer, cosmetic, and pharmaceutical industries. LA production bioprocesses using microorganisms are economically viable compared to chemical synthesis and can benefit from metabolic engineering for improved productivity, purity, and yield. Strategies to optimize LA productivity in microorganisms on the strain improvement end include modifying metabolic routes, adding gene coding for lactate transporters, inducing tolerance to organic acids, and choosing cheaper carbon sources as fuel. Many of the recent advances in this regard have involved the metabolic engineering of yeasts and filamentous fungi to produce LA due to their versatility in fuel choice and tolerance of industrial-scale culture conditions such as pH and temperature. This review aims to compile and discuss metabolic engineering innovations in LA production in yeasts and filamentous fungi over the 2013-2023 period, and present future directions of research in this area, thus bringing researchers in the field up to date with recent advances.

A potent candicidal peptide designed based on an encrypted peptide from a proteinase inhibitor.

Antimicrobial peptides (AMP) represent an alternative in the treatment of fungal infections associated with countless deaths. Here, we report a new AMP, named KWI-19, which was designed based on a peptide encrypted in the sequence of an Inga laurina Kunitz-type inhibitor (ILTI). KWI-19 inhibited the growth of Candida species and acted as a fungicidal agent from 2.5 to 20 µmol L-1, also showing synergistic activity with amphotericin B. Kinetic assays showed that KWI-19 killed Candida tropicalis cells within 60 min. We also report the membrane-associated mechanisms of action of KWI-19 and its interaction with ergosterol. KWI-19 was also characterized as a potent antibiofilm peptide, with activity against C. tropicalis. Finally, non-toxicity was reported against Galleria mellonella larvae, thus strengthening the interest in all the bioactivities mentioned above. This study extends our knowledge on how AMPs can be engineered from peptides encrypted in larger proteins and their potential as candicidal agents.

Unwrapping the structural and functional features of antimicrobial peptides from wasp venoms.

The study of wasp venoms has captured attention due to the presence of a wide variety of active compounds, revealing a diverse array of biological effects. Among these compounds, certain antimicrobial peptides (AMPs) such as mastoparans and chemotactic peptides have emerged as significant players, characterized by their unique amphipathic short linear alpha-helical structure. These peptides exhibit not only antibiotic properties but also a range of other biological activities, which are related to their ability to interact with biological membranes to varying degrees. This review article aims to provide updated insights into the structure/function relationships of AMPs derived from wasp venoms, linking this knowledge to the potential development of innovative treatments against infections.

Computer-made peptide RQ18 acts as a dual antifungal and antibiofilm peptide though membrane-associated mechanisms of action.

The spread of fungi resistant to conventional drugs has become a threatening problem. In this context, antimicrobial peptides (AMPs) have been considered as one of the main alternatives for controlling fungal infections. Here, we report the antifungal and antibiofilm activity and some clues about peptide RQ18's mechanism of action against Candida and Cryptococcus. This peptide inhibited yeast growth from 2.5 µM and killed all Candida tropicalis cells within 2 h incubation. Moreover, it showed a synergistic effect with antifungal agent the amphotericin b. RQ18 reduced biofilm formation and promoted C. tropicalis mature biofilms eradication. RQ18's mechanism of action involves fungal cell membrane damage, which was confirmed by the results of RQ18 in the presence of free ergosterol in the medium and fluorescence microscopy by Sytox green. No toxic effects were observed in murine macrophage cell lines and Galleria mellonella larvae, suggesting fungal target selectivity. Therefore, peptide RQ18 represents a promising strategy as a dual antifungal and antibiofilm agent that contributes to infection control without damaging mammalian cells.

From exploring cancer and virus targets to discovering active peptides through mRNA display.

During carcinogenesis, neoplastic cells accumulate mutations in genes important for cellular homeostasis, producing defective proteins. Viral infections occur when viral capsid proteins bind to the host cell receptor, allowing the virus to enter the cells. In both cases, proteins play important roles in cancer development and viral infection, so these targets can be exploited to develop alternative treatments. mRNA display technology is a very powerful tool for the development of peptides capable of acting on specific targets in neoplastic cells or on viral capsid proteins. mRNA display technology allows the selection and evolution of peptides with desired functional properties from libraries of many nucleic acid variants. Among other advantages of this technology, the use of flexizymes allows the production of peptides with unnatural amino acid residues, which can enhance the activity of these molecules. From target immobilization, peptides with greater specificity for the targets of interest are generated during the selection rounds. Herein, we will explore the use of mRNA display technology for the development of active peptides after successive rounds of selection, using proteins present in neoplastic cells and viral particles as targets.

Peptide Stapling Applied to Antimicrobial Peptides.

Antimicrobial peptides (AMPs) are considered a promising therapeutic approach against multi-drug resistant microorganisms. Besides their advantages, there are limitations to be overcome so that these molecules can become market competitive. One of the biggest limitations is proteolytic susceptibility, which could be overcome by structural modifications such as cyclization, especially for helix-constraining strategies. Over the years, many helix stabilization techniques have arisen, such as lactam-bridging, triazole-based, N-alkylation and all-hydrocarbon stapling. All-hydrocarbon stapling takes advantage of modified amino acid residues and olefinic cross-linking to constrain peptide helices. Despite being a well-established strategy and presenting efficient stability results, there are different limitations especially related to toxicity. In this review, recent studies on stapled AMPs for antimicrobial usage are explored with the aim of understanding the future of these molecules as putative antimicrobial agents.

Anti-Protozoan Activities of Polar Fish-Derived Polyalanine Synthetic Peptides.

Chagas disease, sleeping sickness and malaria are infectious diseases caused by protozoan parasites that kill millions of people worldwide. Here, we performed in vitro assays of Pa-MAP, Pa-MAP1.9, and Pa-MAP2 synthetic polyalanine peptides derived from the polar fish Pleuronectes americanus toward Trypanosoma cruzi, T. brucei gambiense and Plasmodium falciparum activities. We demonstrated that the peptides Pa-MAP1.9 and Pa-MAP2 were effective to inhibit T. brucei growth. In addition, structural analyses using molecular dynamics (MD) studies showed that Pa-MAP2 penetrates deeper into the membrane and interacts more with phospholipids than Pa-MAP1.9, corroborating the previous in vitro results showing that Pa-MAP1.9 acts within the cell, while Pa-MAP2 acts via membrane lysis. In conclusion, polyalanine Pa-MAP1.9 and Pa-MAP2 presented activity against bloodstream forms of T. b. gambiense, thus encouraging further studies on the application of these peptides as a treatment for sleeping sickness.

Host defense peptides combined with MTA extract increase the repair in dental pulp cells: in vitro and ex vivo study.

Host Defense Peptides (HDPs) have, in previous studies, been demonstrating antimicrobial, anti-inflammatory, and immunomodulatory capacity, important factors in the repair process. Knowing these characteristics, this article aims to evaluate the potential of HDPs IDR1018 and DJK-6 associated with MTA extract in the repair process of human pulp cells. Antibacterial activity of HDPs, MTA and HDPs combined with MTA in Streptococcus mutans planktonic bacteria and antibiofilm activity was evaluated. Cell toxicity was assayed with MTT and cell morphology was observed by scanning electron microscopy (SEM). Proliferation and migration of pulp cells were evaluated by trypan blue and wound healing assay. Inflammatory and mineralization related genes were evaluated by qPCR (IL-6, TNFRSF, DSPP, TGF-ß). Alkaline phosphatase, phosphate quantification and alizarin red staining were also verified. The assays were performed in technical and biological triplicate (n = 9). Results were submitted for the calculation of the mean and standard deviation. Then, normality verification by Kolmogorov Smirnov test, analyzing one-way ANOVA. Analyses were considered at a 95% significance level, with a p-value < 0.05. Our study demonstrated that HDPs combined with MTA were able to reduce biofilms performed in 24 h and biofilm performed over 7 days S. mutans biofilm (p < 0.05). IDR1018 and MTA, as well as their combination, down-regulated IL-6 expression (p < 0.05). Tested materials were not cytotoxic to pulp cells. IDR1018 induced high cell proliferation and combined with MTA induced high cellular migration rates in 48 h (p < 0.05). Furthermore, the combination of IDR1018 and MTA also induced high expression levels of DSPP, ALP activity, and the production of calcification nodules. So, IDR-1018 and its combination with MTA could assist in pulp-dentine complex repair process in vitro.

Pathogenesis-Related Proteins (PRs) with Enzyme Activity Activating Plant Defense Responses.

Throughout evolution, plants have developed a highly complex defense system against different threats, including phytopathogens. Plant defense depends on constitutive and induced factors combined as defense mechanisms. These mechanisms involve a complex signaling network linking structural and biochemical defense. Antimicrobial and pathogenesis-related (PR) proteins are examples of this mechanism, which can accumulate extra- and intracellular space after infection. However, despite their name, some PR proteins are present at low levels even in healthy plant tissues. When they face a pathogen, these PRs can increase in abundance, acting as the first line of plant defense. Thus, PRs play a key role in early defense events, which can reduce the damage and mortality caused by pathogens. In this context, the present review will discuss defense response proteins, which have been identified as PRs, with enzymatic action, including constitutive enzymes, ß-1,3 glucanase, chitinase, peroxidase and ribonucleases. From the technological perspective, we discuss the advances of the last decade applied to the study of these enzymes, which are important in the early events of higher plant defense against phytopathogens.

Proteomic Insights of Cowpea Response to Combined Biotic and Abiotic Stresses.

The co-occurrence of biotic and abiotic stresses in agricultural areas severely affects crop performance and productivity. Drought is one of the most adverse environmental stresses, and its association with root-knot nematodes further limits the development of several economically important crops, such as cowpea. Plant responses to combined stresses are complex and require novel adaptive mechanisms through the induction of specific biotic and abiotic signaling pathways. Therefore, the present work aimed to identify proteins involved in the resistance of cowpea to nematode and drought stresses individually and combined. We used the genotype CE 31, which is resistant to the root-knot nematode Meloidogyne spp. And tolerant to drought. Three biological replicates of roots and shoots were submitted to protein extraction, and the peptides were evaluated by LC-MS/MS. Shotgun proteomics revealed 2345 proteins, of which 1040 were differentially abundant. Proteins involved in essential biological processes, such as transcriptional regulation, cell signaling, oxidative processes, and photosynthesis, were identified. However, the main defense strategies in cowpea against cross-stress are focused on the regulation of hormonal signaling, the intense production of pathogenesis-related proteins, and the downregulation of photosynthetic activity. These are key processes that can culminate in the adaptation of cowpea challenged by multiple stresses. Furthermore, the candidate proteins identified in this study will strongly contribute to cowpea genetic improvement programs.

Interaction of Pexiganan (MSI-78)-Derived Analogues Reduces Inflammation and TLR4-Mediated Cytokine Secretion: A Comparative Study.

Antibiotic-resistant bacterial infections have increased the prevalence of sepsis and septic shock mortality worldwide and have become a global concern. Antimicrobial peptides (AMPs) show remarkable properties for developing new antimicrobial agents and host response modulatory therapies. A new series of AMPs derived from pexiganan (MSI-78) were synthesized. The positively charged amino acids were segregated at their N- and C-termini, and the rest of the amino acids created a hydrophobic core surrounded by positive charges and were modified to simulate the lipopolysaccharide (LPS). The peptides were investigated for their antimicrobial activity and LPS-induced cytokine release inhibition profile. Various biochemical and biophysical methods were used, including attenuated total reflection Fourier transform infrared (ATR-FTIR) spectroscopy, microscale thermophoresis (MST), and electron microscopy. Two new AMPs, MSI-Seg-F2F and MSI-N7K, preserved their neutralizing endotoxin activity while reducing toxicity and hemolytic activity. Combining all of these properties makes the designed peptides potential candidates to eradicate bacterial infection and detoxify LPS, which might be useful for sepsis treatment.

The Combination of Synoeca-MP Antimicrobial Peptide with IDR-1018 Stimulates Proliferation, Migration, and the Expression of Pro-Regenerative Genes in Both Human Skin Cell Cultures and 3D Skin Equivalents.

In skin lesions, the development of microbial infection affects the healing process, increasing morbidity and mortality rates in patients with severe burns, diabetic foot, and other types of skin injuries. Synoeca-MP is an antimicrobial peptide (AMP) that exhibits activity against several bacteria of clinical importance, but its cytotoxicity can represent a problem for its positioning as an effective antimicrobial compound. In contrast, the immunomodulatory peptide IDR-1018 presents low toxicity and a wide regenerative potential due to its ability to reduce apoptotic mRNA expression and promote skin cell proliferation. In the present study, we used human skin cells and a 3D skin equivalent models to analyze the potential of the IDR-1018 peptide to attenuate the cytotoxicity of synoeca-MP, as well as the influence of synoeca-MP/IDR-1018 combination on cell proliferation, regenerative processes, and wound repair. We found that the addition of IDR-1018 significantly improved the biological properties of synoeca-MP on skin cells without modifying its antibacterial activity against S. aureus. Likewise, in both melanocytes and keratinocytes, the treatment with synoeca-MP/IDR-1018 combination induces cell proliferation and migration, while in a 3D human skin equivalent model, it can accelerate wound reepithelization. Furthermore, treatment with this peptide combination generates an up-regulation in the expression of pro-regenerative genes in both monolayer cell cultures and in 3D skin equivalents. This data suggests that the synoeca-MP/IDR-1018 combination possesses a good profile of antimicrobial and pro-regenerative activity, opening the door to the development of new strategies for the treatment of skin lesions.

Expanding therapeutic potential of Bdellovibrio bacteriovorus against multidrug-resistant pathogens.

Novel treatments toward Gram-negative bacteria are urgently needed to prevent even higher mortality levels associated with resistant bacterial infections. Predatory bacteria have been studied as a new type of treatment against pathogenic bacteria, including resistant species. However, because of limitations related to eradication efficacy, combination therapy using predatory bacteria with other agents has also been tested. Here, we discuss recent advances in the use of predatory bacteria to treat infections and propose novel combinatory strategies with antivirulence compounds.