Different genetic profiles contribute to worse overall survival in patients with leptomeningeal metastases of non-small-cell lung cancer.

BACKGROUND: To assess the genetic characteristics of central nervous system (CNS) metastases from non-small-cell lung cancer (NSCLC), we gathered the genetic profiles of brain metastases (BM) and leptomeningeal metastases (LM). Our objective was to identify genetic factors contributing to poorer overall survival (OS) in NSCLC patients with LM. METHODS: This study included 25 consecutive patients with BM and 52 patients with LM from Guangdong Sanjiu Brain Hospital. All participants underwent 168-target panel sequencing. RESULTS: Among the 25 patients with BM, TP53 was the most frequently mutated gene (44%), followed by driver genes such as EGFR and BRAF (40% and 20%, respectively). In patients with BM, EGFR_amp and CDK4 were also frequently mutated, with rates of 20% and 16%, respectively. The genetic landscape of patients with LM differed, with the top mutated genes being EGFR, TP53, EGFR_amp, CDKN2A, CCNE1, CDK4, PMS2, and PIK3CA, with mutation rates of 77%, 69%, 31%, 29%, 13%, 13%, 13%, and 12%, respectively. In our study, patients with LM exhibited significantly worse OS compared to those with BM (p = 0.029). The mutation rates of TP53, EGFR_amp, and CDKN2A varied between patients with LM and those with BM, at 69.23% vs. 44%, 30.77% vs. 20%, and 28.85% vs. 12%, respectively. Further exploration revealed that patients with BM with TP53 mutations had a shorter OS than patients without TP53 mutations (p = 0.014). Similarly, patients with LM and TP53 mutations presented with worse OS than those without TP53 mutations (p = 0.0067). LM patients with CDKN2A deletions had worse OS than those without CDKN2A deletions (p = 0.037). Additionally, patients with EGFR_amp had a shorter OS than those without EGFR_amp (p = 0.044). CONCLUSIONS: Patients with LM exhibited significantly worse OS than those with BM. Gene signatures, such as TP53, EGFR_amp, and CDKN2A, may account for shorter outcomes in patients with LM.

The ecto-3'-nucleotidase activity of Acanthamoeba castellanii trophozoites increases their adhesion to host cells through the generation of extracellular adenosine.

Acanthamoeba castellanii, a free-living amoeba, can be pathogenic to humans causing a corneal infection named Acanthamoeba keratitis (AK). The mannose-binding protein (MBP) is well established as the major factor related to Acanthamoeba pathogenesis. However, additional factors that participate in the adhesion process and protect trophozoites from cytolytic effects caused by host immune responses remain unknown. Ectonucleotidases, including 3'-nucleotidase/nuclease (3'-NT/NU), a bifunctional enzyme that was recently reported in A. castellanii, are frequently related to the establishment of parasitic infections. We verified that trophozoites can hydrolyze 3'-AMP, and this activity is similar to that observed in other protists. The addition of 3'-AMP increases the adhesion of trophozoites to LLC-MK2 epithelial cells, and this stimulation is completely reversed by DTT, an inhibitor of ecto-3'-nucleotidase activity. Lesions in corneal cells caused by AK infection may elevate the extracellular level of 3'-AMP. We believe that ecto-3'-nucleotidase activity can modulate the host immune response, thus facilitating the establishment of parasitic infection. This activity results from the generation of extracellular adenosine, which can bind to purinergic receptors present in host immune cells. Positive feedback may occur in this cascade of events once the ecto-3'-nucleotidase activity of trophozoites is increased by the adhesion of trophozoites to LLC-MK2 cells.

Tetracyclic homoisoflavanoid (+)-brazilin: a natural product inhibits c-di-AMP-producing enzyme and Streptococcus mutans biofilms.

The tenacious biofilms formed by Streptococcus mutans are resistant to conventional antibiotics and current treatments. There is a growing need for novel therapeutics that selectively inhibit S. mutans biofilms while preserving the normal oral microenvironment. Previous studies have shown that increased levels of cyclic di-AMP, an important secondary messenger synthesized by diadenylate cyclase (DAC), favored biofilm formation in S. mutans. Thus, targeting S. mutans DAC is a novel strategy to inhibit S. mutans biofilms. We screened a small NCI library of natural products using a fluorescence detection assay. (+)-Brazilin, a tetracyclic homoisoflavanoid found in the heartwood of Caesalpinia sappan, was identified as one of the 11 "hits," with the greatest reduction (>99%) in fluorescence at 100 µM. The smDAC inhibitory profiles of the 11 "hits" established by a quantitative high-performance liquid chromatography assay revealed that (+)-brazilin had the most enzymatic inhibitory activity (87% at 100 µM) and was further studied to determine its half maximal inhibitory concentration (IC50 = 25.1 ± 0.98 µM). (+)-Brazilin non-competitively inhibits smDAC's enzymatic activity (Ki = 140.0 ± 27.13 µM), as determined by a steady-state Michaelis-Menten kinetics assay. In addition, (+)-brazilin's binding profile with smDAC (Kd = 11.87 µM) was illustrated by a tyrosine intrinsic fluorescence quenching assay. Furthermore, at low micromolar concentrations, (+)-brazilin selectively inhibited the biofilm of S. mutans (IC50 = 21.0 ± 0.60 µM) and other oral bacteria. S. mutans biofilms were inhibited by a factor of 105 in colony-forming units when treated with 50 µM (+)-brazilin. In addition, a significant dose-dependent reduction in extracellular DNA and glucan levels was evident by fluorescence microscopy imaging of S. mutans biofilms exposed to different concentrations of (+)-brazilin. Furthermore, colonization of S. mutans on a representative model of enamel using suspended hydroxyapatite discs showed a >90% reduction with 50 µM (+)-brazilin. In summary, we have identified a drug-like natural product inhibitor of S. mutans biofilm that not only binds to smDAC but can also inhibit the function of smDAC. (+)-Brazilin could be a good candidate for further development as a potent therapeutic for the prevention and treatment of dental caries.IMPORTANCEThis study represents a significant advancement in our understanding of potential therapeutic options for combating cariogenic biofilms produced by Streptococcus mutans. The research delves into the use of (+)-brazilin, a natural product, as a potent inhibitor of Streptococcus mutans' diadenylate cyclase (smDAC), an enzyme crucial in the formation of biofilms. The study establishes (+)-brazilin as a non-competitive inhibitor of smDAC while providing initial insights into its binding mechanism. What makes this finding even more promising is that (+)-brazilin does not limit its inhibitory effects to S. mutans alone. Instead, it demonstrates efficacy in hindering biofilms in other oral bacteria as well. The broader spectrum of anti-biofilm activity suggests that (+)-brazilin could potentially serve as a versatile tool in a natural product-based treatment for combating a range of conditions caused by resilient biofilms.

Therapeutic potential of antimicrobial peptides against pathogenic protozoa.

Protozoal infections cause significant morbidity and mortality in humans and animals. The use of several antiprotozoal drugs is associated with serious adverse effects and resistance development, and drugs that are more effective are urgently needed. Microorganisms, mammalian cells and fluids, insects, and reptiles are sources of antimicrobial peptides (AMPs) that act against pathogenic microorganisms; these AMPs have been widely studied as a promising alternative therapeutic option to conventional antibiotics, aiming to treat infections caused by multidrug-resistant pathogens. One advantage of AMP molecules is their adaptability, as they can be easily fine-tuned for broad-spectrum or targeted activity by changing the amino acid residues in their sequence. Consequently, these variations in structural and physicochemical properties can alter the antimicrobial activities of AMPs and decrease resistance development. This article presents an overview of peptide activities against amebiasis, giardiasis, trichomoniasis, Chagas disease, leishmaniasis, malaria, and toxoplasmosis. AMPs and their analogs demonstrate great potential as therapeutics, with potent and selective activity, when compared with commercially available drugs, and hold the potential to act as new scaffolds for the development of novel anti-protozoal drugs.

The dance of proteostasis and metabolism: Unveiling the caloristatic controlling switch.

The heat shock response (HSR) is an ancient and evolutionarily conserved mechanism designed to restore cellular homeostasis following proteotoxic challenges. However, it has become increasingly evident that disruptions in energy metabolism also trigger the HSR. This interplay between proteostasis and energy regulation is rooted in the fundamental need for ATP to fuel protein synthesis and repair, making the HSR an essential component of cellular energy management. Recent findings suggest that the origins of proteostasis-defending systems can be traced back over 3.6 billion years, aligning with the emergence of sugar kinases that optimized glycolysis around 3.594 billion years ago. This evolutionary connection is underscored by the spatial similarities between the nucleotide-binding domain of HSP70, the key player in protein chaperone machinery, and hexokinases. The HSR serves as a hub that integrates energy metabolism and resolution of inflammation, further highlighting its role in maintaining cellular homeostasis. Notably, 5'-adenosine monophosphate-activated protein kinase emerges as a central regulator, promoting the HSR during predominantly proteotoxic stress while suppressing it in response to predominantly metabolic stress. The complex relationship between 5'-adenosine monophosphate-activated protein kinase and the HSR is finely tuned, with paradoxical effects observed under different stress conditions. This delicate equilibrium, known as caloristasis, ensures that cellular homeostasis is maintained despite shifting environmental and intracellular conditions. Understanding the caloristatic controlling switch at the heart of this interplay is crucial. It offers insights into a wide range of conditions, including glycemic control, obesity, type 2 diabetes, cardiovascular and neurodegenerative diseases, reproductive abnormalities, and the optimization of exercise routines. These findings highlight the profound interconnectedness of proteostasis and energy metabolism in cellular function and adaptation.

Ag85B with c-di-AMP as mucosal adjuvant showed immunotherapeutic effects on persistent Mycobacterium tuberculosis infection in mice

Tuberculosis (TB), caused by Mycobacterium tuberculosis, remains the leading cause of mortality by a single infectious agent in the world. M. tuberculosis infection could also result in clinical chronic infection, known as latent TB infection (LTBI). Compared to the current limited treatment, several subunit vaccines showed immunotherapeutic effects and were included in clinical trials. In this study, a subunit vaccine of Ag85B with a novel mucosal adjuvant c-di-AMP (Ag85B:c-di-AMP) was delivered intranasally to a persistent M. tuberculosis H37Ra infection mouse model, which also presented the asymptomatic characteristics of LTBI. Compared with Ag85B immunization, Ag85B:c-di-AMP vaccination induced stronger humoral immune responses, significantly higher CD4+ T cells recruitment, enhanced Th1/Th2/Th17 profile response in the lung, decreased pathological lesions of the lung, and reduced M. tuberculosis load in mice. Taken together, Ag85B:c-di-AMP mucosal route immunization provided an immunotherapeutic effect on persistent M. tuberculosis H37Ra infection, and c-di-AMP, as a promising potential mucosal adjuvant, could be further used in therapeutic or prophylactic vaccine strategies for persistent M. tuberculosis infection as well as LTBI.

Antifungal, Antimycobacterial, Protease and α‒Amylase Inhibitory Activities of a Novel Serine Bifunctional Protease Inhibitor from Adenanthera pavonina L. Seeds.

Antifungal resistance poses a significant challenge to disease management, necessitating the development of novel drugs. Antimicrobial peptides offer potential solutions. This study focused on extraction and characterization of peptides from Adenanthera pavonina seeds with activity against Candida species, Mycobacterium tuberculosis, proteases, and α-amylases. Peptides were extracted in phosphate buffer and heated at 90°C for 10 min to create a peptide rich heated fraction (PRHF). After confirming antimicrobial activity and the presence of peptides, the PRHF underwent ion exchange chromatography, yielding retained and non-retained fractions. These fractions were evaluated for antimicrobial activity and cytotoxicity against murine macrophages. The least toxic and most active fraction underwent reversed-phase chromatography, resulting in ten fractions. These fractions were tested for peptides and antimicrobial activity. The most active fraction was rechromatographed on a reversed-phase column, resulting in two fractions that were assessed for antimicrobial activity. The most active fraction revealed a single band of approximately 6 kDa and was tested for inhibitory effects on proteases and α-amylases. Thermal stability experiments were conducted on the 6 kDa peptide at different temperatures followed by reassessment of antifungal activity and circular dichroism. The 6 kDa peptide inhibited yeasts, M. tuberculosis, human salivary and Tenebrio molitor larvae intestine α-amylases, and proteolytic activity from fungal extracts, and thus named ApPI. Remarkably, ApPI retained antifungal activity and conformation after heating and is primarily composed of α-helices. ApPI is a thermally stable serine protease/α-amylase inhibitor from A. pavonina seeds, offering promise as a foundational molecule for innovative therapeutic agents against fungal infections and tuberculosis.

Nucleotides as Bacterial Second Messengers.

In addition to comprising monomers of nucleic acids, nucleotides have signaling functions and act as second messengers in both prokaryotic and eukaryotic cells. The most common example is cyclic AMP (cAMP). Nucleotide signaling is a focus of great interest in bacteria. Cyclic di-AMP (c-di-AMP), cAMP, and cyclic di-GMP (c-di-GMP) participate in biological events such as bacterial growth, biofilm formation, sporulation, cell differentiation, motility, and virulence. Moreover, the cyclic-di-nucleotides (c-di-nucleotides) produced in pathogenic intracellular bacteria can affect eukaryotic host cells to allow for infection. On the other hand, non-cyclic nucleotide molecules pppGpp and ppGpp are alarmones involved in regulating the bacterial response to nutritional stress; they are also considered second messengers. These second messengers can potentially be used as therapeutic agents because of their immunological functions on eukaryotic cells. In this review, the role of c-di-nucleotides and cAMP as second messengers in different bacterial processes is addressed.

An Update on the Therapeutic Potential of Antimicrobial Peptides against Acinetobacter baumannii Infections.

The rise in antibiotic-resistant strains of clinically important pathogens is a major threat to global health. The World Health Organization (WHO) has recognized the urgent need to develop alternative treatments to address the growing list of priority pathogens. Antimicrobial peptides (AMPs) rank among the suggested options with proven activity and high potential to be developed into effective drugs. Many AMPs are naturally produced by living organisms protecting the host against pathogens as a part of their innate immunity. Mechanisms associated with AMP actions include cell membrane disruption, cell wall weakening, protein synthesis inhibition, and interference in nucleic acid dynamics, inducing apoptosis and necrosis. Acinetobacter baumannii is a critical pathogen, as severe clinical implications have developed from isolates resistant to current antibiotic treatments and conventional control procedures, such as UV light, disinfectants, and drying. Here, we review the natural AMPs representing primary candidates for new anti-A. baumannii drugs in post-antibiotic-era and present computational tools to develop the next generation of AMPs with greater microbicidal activity and reduced toxicity.

Total and Extracellular Vesicle cAMP Contents in Urine Are Associated with Autosomal Dominant Polycystic Kidney Disease (ADPKD) Progression.

ADPKD is the most common genetic renal disease, characterized by the presence of multiple cysts which, through slow and gradual growth, lead to glomerular filtration rate (GFR) decline and end-stage renal disease. Cystic growth is associated with increased intracellular levels of 3',5'-cyclic adenosine monophosphate (cAMP). Extracellular vesicles (EVs) are proposed to participate in "remote sensing" by transporting different cargoes, but their relevance to ADPKD progression is poorly understood. This study aimed to determine whether cAMP is contained in urinary EVs and, if so, how total and/or EV cAMP contents participate in disease progression. Fourteen ADPKD patients, naïve for V2 receptor antagonism treatment, and seven controls were studied. Progression was evaluated by estimating GFR (eGFR) and height-adjusted total kidney volume (htTKV). Fresh morning urine was collected to determine cAMP by the competitive radioligand assay. Urine EVs were isolated using an adapted centrifugation method and characterized by electron microscopy, dynamic light scanning, flow cytometry with FITC CD63 labeling, protein and RNA content, and AQP2 and GAPDH mRNA detection. Total and EV cAMP was measurable in both control and patient urine samples. Total cAMP was significantly correlated with eGFR and its annual change but inversely correlated with htTKV. The cAMP-EVs showed a bimodal pattern with htTKV, increasing to ~1 L/m and falling at larger sizes. Our results demonstrate that urine cAMP correlates with ADPKD progression markers, and that its extracellular delivery by EVs could reflect the architectural disturbances of the organ.

Adenosine metabolism by mesenchymal stromal cells isolated from different human tissues.

Mesenchymal stromal cells (MSCs) have unique biological properties and play important functions, which make them attractive tools for cell-based therapies. The basic mechanisms of these cells are not fully understood. However, the adenosinergic pathway contributes to the main effects attributed to MSCs. Adenosine is a highly immunosuppressive molecule and exerts a central role in inflammation by neutralizing the proinflammatory ATP influence. This nucleoside is produced by purinergic signaling, an important physiological pathway for MSCs, which involves proliferation, migration, differentiation, and apoptosis. Therefore, in this study, we analyzed the extracellular AMP hydrolysis and consequent adenosine production, as well as the expression of CD73 and adenosine receptors on the cell surface of MSCs isolated from different human tissues: dermis (D-MSCs), adipose tissue (AD-MSCs), and umbilical cord (UC-MSCs). All cells confirmed their multipotent capacity by adipogenic, osteogenic, and chondrogenic differentiation, as well as the expression of cell surface markers including CD44 + , CD105 + , and CD90 + . All MSCs expressed similar levels of CD73 and CD26 without a statistical difference among the different tissues, whereas ADA expression was lower in AD-MSCs. In addition, A1R and A3R mRNA levels were higher in D-MSCs and AD-MSCs, respectively. Enzymatic assay showed that AD-MSCs have the highest hydrolysis rate of AMP, leading to increased amount of adenosine production. Moreover, despite all MSCs completely hydrolyze extracellular AMP generating adenosine, the pattern of nucleosides metabolism was different. Therefore, although MSCs share certain characteristics as the multilineage potential and immunophenotype, they show different adenosinergic profiles according to tissue origin.

Impact of the cAMP efflux and extracellular cAMP-adenosine pathway on airway smooth muscle relaxation induced by formoterol and phosphodiesterase inhibitors.

ß2-adrenoceptors agonists and phosphodiesterase (PDE) inhibitors are effective bronchodilators, due to their ability to increase intracellular cyclic AMP (cAMP) levels and induce airway smooth muscle (ASM) relaxation. We have shown that increment of intracellular cAMP induced by ß2-adrenoceptors agonist fenoterol is followed by efflux of cAMP, which is converted by ecto-PDE and ecto-5'-nucleotidases (ecto-5'NT) to adenosine, leading to ASM contraction. Here we evaluate whether other classical bronchodilators used to treat asthma and chronic obstructive pulmonary disease (COPD) could induce cAMP efflux and, as consequence, influence the ASM contractility. Our results showed that ß2-adrenoceptor agonists formoterol and PDE inhibitors IBMX, aminophylline and roflumilast induced cAMP efflux and a concentration-dependent relaxation of rat trachea precontracted with carbachol. Pretreatment of tracheas with MK-571 (MRP transporter inhibitor), AMP-CP (ecto-5'NT inhibitor) or CGS-15943 (nonselective adenosine receptor antagonist) potentiated the relaxation induced by ß2-adrenoceptor agonists but did not change the relaxation induced by PDE inhibitors. These data showed that all bronchodilators tested were able to induce cAMP efflux. However, only ß2-adrenoceptor-induced relaxation of tracheal smooth muscle was affected by cAMP efflux and extracellular cAMP-adenosine pathway.

Electroencephalography Signal Analysis for Human Activities Classification: A Solution Based on Machine Learning and Motor Imagery.

Electroencephalography (EEG) is a fundamental tool for understanding the brain's electrical activity related to human motor activities. Brain-Computer Interface (BCI) uses such electrical activity to develop assistive technologies, especially those directed at people with physical disabilities. However, extracting signal features and patterns is still complex, sometimes delegated to machine learning (ML) algorithms. Therefore, this work aims to develop a ML based on the Random Forest algorithm to classify EEG signals from subjects performing real and imagery motor activities. The interpretation and correct classification of EEG signals allow the development of tools controlled by cognitive processes. We evaluated our ML Random Forest algorithm using a consumer and a research-grade EEG system. Random Forest efficiently distinguishes imagery and real activities and defines the related body part, even with consumer-grade EEG. However, interpersonal variability of the EEG signals negatively affects the classification process.

On the Significance of the ADNT1 Carrier in Arabidopsis thaliana under Waterlogging Conditions.

Among the adenylate carriers identified in Arabidopsis thaliana, only the AMP/ATP transporter ADNT1 shows increased expression in roots under waterlogging stress conditions. Here, we investigated the impact of a reduced expression of ADNT1 in A. thaliana plants submitted to waterlogging conditions. For this purpose, an adnt1 T-DNA mutant and two ADNT1 antisense lines were evaluated. Following waterlogging, ADNT1 deficiency resulted in a reduced maximum quantum yield of PSII electron transport (significantly for adnt1 and antisense Line 10), indicating a higher impact caused by the stress in the mutants. In addition, ADNT1 deficient lines showed higher levels of AMP in roots under nonstress condition. This result indicates that the downregulation of ADNT1 impacts the levels of adenylates. ADNT1-deficient plants exhibited a differential expression pattern of hypoxia-related genes with an increase in non-fermenting-related-kinase 1 (SnRK1) expression and upregulation of adenylate kinase (ADK) under stress and non-stress conditions. Together, these results indicated that the lower expression of ADNT1 is associated with an early "hypoxic status" due to the perturbation of the adenylate pool caused by reduced AMP import by mitochondria. This perturbation, which is sensed by SnRK1, results in a metabolic reprogramming associated with early induction of the fermentative pathway in ADNT1 deficient plants.

Intranasal trans-sialidase-based vaccine against Trypanosoma cruzi triggers a mixed cytokine profile in the nasopharynx-associated lymphoid tissue and confers local and systemic immunogenicity.

Trypanosoma cruzi, the agent of Chagas disease, can infect through conjunctive or oral mucosas. Therefore, the induction of mucosal immunity by vaccination is relevant not only to trigger local protection but also to stimulate both humoral and cell-mediated responses in systemic sites to control parasite dissemination. In a previous study, we demonstrated that a nasal vaccine based on a Trans-sialidase (TS) fragment plus the mucosal STING agonist c-di-AMP, was highly immunogenic and elicited prophylactic capacity. However, the immune profile induced by TS-based nasal vaccines at the nasopharyngeal-associated lymphoid tissue (NALT), the target site of nasal immunization, remains unknown. Hence, we analyzed the NALT cytokine expression generated by a TS-based vaccine plus c-di-AMP (TSdA+c-di-AMP) and their association with mucosal and systemic immunogenicity. The vaccine was administered intranasally, in 3 doses separated by 15 days each other. Control groups received TSdA, c-di-AMP, or the vehicle in a similar schedule. We demonstrated that female BALB/c mice immunized intranasally with TSdA+c-di-AMP boosted NALT expression of IFN-γ and IL-6, as well as IFN-ß and TGF-ß. TSdA+c-di-AMP increased TSdA-specific IgA secretion in the nasal passages and also in the distal intestinal mucosa. Moreover, T and B-lymphocytes from NALT-draining cervical lymph nodes and spleen showed an intense proliferation after ex-vivo stimulation with TSdA. Intranasal administration of TSdA+c-di-AMP provokes an enhancement of TSdA-specific IgG2a and IgG1 plasma antibodies, accompanied by an increase IgG2a/IgG1 ratio, indicative of a Th1-biased profile. In addition, immune plasma derived from TSdA+c-di-AMP vaccinated mice exhibit in-vivo and ex-vivo protective capacity. Lastly, TSdA+c-di-AMP nasal vaccine also promotes intense footpad swelling after local TSdA challenge. Our data support that TSdA+c-di-AMP nasal vaccine triggers a NALT mixed pattern of cytokines that were clearly associated with an evident mucosal and systemic immunogenicity. These data are useful for further understanding the immune responses elicited by the NALT following intranasal immunization and the rational design of TS-based vaccination strategies for prophylaxis against T. cruzi.

Release of immunomodulatory peptides at bacterial membrane interfaces as a novel strategy to fight microorganisms.

Cationic and amphiphilic peptides can be used as homing devices to accumulate conjugated antibiotics to bacteria-enriched sites and promote efficient microbial killing. However, just as important as tackling bacterial infections, is the modulation of the immune response in this complex microenvironment. In the present report, we designed a peptide chimaera called Chim2, formed by a membrane-active module, an enzyme hydrolysis site and a formyl peptide receptor 2 (FPR2) agonist. This molecule was designed to adsorb onto bacterial membranes, promote their lysis, and upon hydrolysis by local enzymes, release the FPR2 agonist sequence for activation and recruitment of immune cells. We synthesized the isolated peptide modules of Chim2 and characterized their biological activities independently and as a single polypeptide chain. We conducted antimicrobial assays, along with other tests aiming at the analyses of the cellular and immunological responses. In addition, assays using vesicles as models of eukaryotic and prokaryotic membranes were conducted and solution structures of Chim2 were generated by 1H NMR. Chim2 is antimicrobial, adsorbs preferentially to negatively charged vesicles while adopting an α-helix structure and exposes its disorganized tail to the solvent, which facilitates hydrolysis by tryptase-like enzymes, allowing the release of the FPR2 agonist fragment. This fragment was shown to induce accumulation of the cellular activation marker, lipid bodies, in mouse macrophages and the release of immunomodulatory interleukins. In conclusion, these data demonstrate that peptides with antimicrobial and immunomodulatory activities can be considered for further development as drugs.

Receptor-binding domain-based SARS-CoV-2 vaccine adjuvanted with cyclic di-adenosine monophosphate enhances humoral and cellular immunity in mice.

Novel adjuvants are highly desired to improve immune responses of SARS-CoV-2 vaccines. This work reports the potential of the stimulator of interferon genes (STING) agonist adjuvant, the cyclic di-adenosine monophosphate (c-di-AMP), in a SARS-CoV-2 vaccine based on the receptor binding domain (RBD). Here, mice immunized with two doses of monomeric RBD adjuvanted with c-di-AMP intramuscularly were found to exhibit stronger immune responses compared to mice vaccinated with RBD adjuvanted with aluminum hydroxide (Al(OH)3 ) or without adjuvant. After two immunizations, consistent enhancements in the magnitude of RBD-specific immunoglobulin G (IgG) antibody response were observed by RBD + c-di-AMP (mean: 15360) compared to RBD + Al(OH)3 (mean: 3280) and RBD alone (n.d.). Analysis of IgG subtypes indicated a predominantly Th1-biased immune response (IgG2c, mean: 14480; IgG2b, mean: 1040, IgG1, mean: 470) in mice vaccinated with RBD + c-di-AMP compared to a Th2-biased response in those vaccinated with RBD + Al(OH)3 (IgG2c, mean: 60; IgG2b: n.d.; IgG1, mean: 16660). In addition, the RBD + c-di-AMP group showed better neutralizing antibody responses as determined by pseudovirus neutralization assay and by plaque reduction neutralization assay with SARS-CoV-2 wild type. Moreover, the RBD + c-di-AMP vaccine promoted interferon-γ secretion of spleen cell cultures after RBD stimulation. Furthermore, evaluation of IgG-antibody titers in aged mice showed that di-AMP was able to improve RBD-immunogenicity at old age after 3 doses (mean: 4000). These data suggest that c-di-AMP improves immune responses of a SARS-CoV-2 vaccine based on RBD, and would be considered a promising option for future COVID-19 vaccines.

Antimicrobial Spectrum of Activity and Mechanism of Action of Linear Alpha-Helical Peptides Inspired by Shrimp Anti-Lipopolysaccharide Factors.

Shrimp antilipopolysaccharide factors (ALFs) form a multifunctional and diverse family of antimicrobial host defense peptides (AMPs) composed of seven members (groups A to G), which differ in terms of their primary structure and biochemical properties. They are amphipathic peptides with two conserved cysteine residues stabilizing a central ß-hairpin that is understood to be the core region for their biological activities. In this study, we synthetized three linear (cysteine-free) peptides based on the amino acid sequence of the central ß-hairpin of the newly identified shrimp (Litopenaeus vannamei) ALFs from groups E to G. Unlike whole mature ALFs, the ALF-derived peptides exhibited an α-helix secondary structure. In vitro assays revealed that the synthetic peptides display a broad spectrum of activity against both Gram-positive and Gram-negative bacteria and fungi but not against the protozoan parasites Trypanosoma cruzi and Leishmania (L.) infantum. Remarkably, they displayed synergistic effects and showed the ability to permeabilize bacterial membranes, a mechanism of action of classical AMPs. Having shown low cytotoxicity to THP-1 human cells and being active against clinical multiresistant bacterial isolates, these nature-inspired peptides represent an interesting class of bioactive molecules with biotechnological potential for the development of novel therapeutics in medical sciences.

The biological role of charge distribution in linear antimicrobial peptides.

INTRODUCTION: Antimicrobial peptides (AMP) have received particular attention due to their capacity to kill bacteria. Although much is known about them, peptides are currently being further researched. A large number of AMPs have been discovered, but only a few have been approved for topical use, due to their promiscuity and other challenges, which need to be overcome. AREAS COVERED: AMPs are diverse in structure. Consequently, they have varied action mechanisms when targeting microorganisms or eukaryotic cells. Herein, the authors focus on linear peptides, particularly those that are alpha-helical structured, and examine how their charge distribution and hydrophobic amino acids could modulate their biological activity. EXPERT OPINION: The world currently needs urgent solutions to the infective problems caused by resistant pathogens. In order to start the race for antimicrobial development from the charge distribution viewpoint, bioinformatic tools will be necessary. Currently, there is no software available that allows to discriminate charge distribution in AMPs and predicts the biological effects of this event. Furthermore, there is no software available that predicts the side-chain length of residues and its role in biological functions. More specialized software is necessary.

Dietary polyphenols and their relationship to the modulation of non-communicable chronic diseases and epigenetic mechanisms: A mini-review.

Chronic Non-Communicable Diseases (NCDs) have been considered a global health problem, characterized as diseases of multiple factors, which are developed throughout life, and regardless of genetics as a risk factor of important relevance, the increase in mortality attributed to the disease to environmental factors and the lifestyle one leads. Although the reactive species (ROS/RNS) are necessary for several physiological processes, their overproduction is directly related to the pathogenesis and aggravation of NCDs. In contrast, dietary polyphenols have been widely associated with minimizing oxidative stress and inflammation. In addition to their antioxidant power, polyphenols have also drawn attention for being able to modulate both gene expression and modify epigenetic alterations, suggesting an essential involvement in the prevention and/or development of some pathologies. Therefore, this review briefly explained the mechanisms in the development of some NCDs, followed by a summary of some evidence related to the interaction of polyphenols in oxidative stress, as well as the modulation of epigenetic mechanisms involved in the management of NCDs.