Search Results (404)

Atopic dermatitis (AD) is a chronic inflammatory skin disorder associated with immune dysregulation, skin barrier dysfunction, and microbial dysbiosis characterized by Staphylococcus aureus overcolonization and reduced bacterial diversity. Beyond its classical role in calcium homeostasis, Vitamin D (VD) influences skin immunity and microbial composition. This review summarizes current knowledge on VD metabolism, its immunological pathways in AD, and its interactions with the skin microbiome. Recent evidence positions the skin as an active immunological organ rather than a passive barrier. Commensal bacteria such as Staphylococcus epidermidis not only inhibit pathogens by producing bacteriocins and modulins but also generate ceramides and short-chain fatty acids (SCFAs) that stabilize the lipid barrier. Moreover, dermal fibroblasts and preadipocytes produce antimicrobial peptides, while resident γδ T cells release growth factors like fibroblast growth factor 7 (FGF7), linking host defense with tissue regeneration. VD modulates AD by suppressing T helper 2 cells/T helper 17 cell responses, enhancing regulatory T cell development, inducing antimicrobial peptides, and strengthening skin and gut barrier integrity. Its interaction with the microbiome and pathways such as SCFA and aryl hydrocarbon receptor (AhR) signaling supports its potential as an adjunctive therapy in AD management. Evidence from mechanistic studies and animal models suggests that VD supplementation may modulate inflammation and microbial diversity. Clinical implications, therapeutic perspectives, and future research directions highlight the potential of VD as a therapeutic adjunct in AD management. Full article

The domesticated silkworm, Bombyx mori, is a highly valued biodiversity and economic asset, acclaimed for its silk production, besides making important contributions to various scientific disciplines. However, the sericulture industry faces ongoing threats from bacterial and viral infections, which severely impact silkworm health and silk yield. This review provides a comprehensive overview of the innate immune response of B. mori against bacterial and viral pathogens, emphasizing the fundamental molecular and cellular defense mechanisms. We explore the humoral and cellular immune response using antimicrobial peptides (AMPs), pattern recognition receptors (PRRs) like peptidoglycan recognition protein (PGRP), and glucan recognition protein (GRP), which activate canonical signaling pathways. The review further highlights the molecular mechanisms underlying the silkworm’s defense against viruses, incorporating RNA interference (RNAi), apoptosis, and distinct signaling pathways such as Toll and Imd, JAK/STAT, and STING. We also discussed the viral suppression strategies and modulation of host metabolism during infection. Furthermore, the review explores the recent use of CRISPR-Cas gene editing to enhance disease resistance, presenting a promising avenue for mitigating pathogen-induced losses in sericulture. By elucidating these mechanisms, the work provides a synthesis that is critical in terms of developing particular interventions and developing more resistant silkworm strains to ensure that the industry of sericulture becomes viable and productive. Full article

Pacific pygmy octopus Paroctopus digueti is a promising model for cephalopod research and aquaculture; its feeding and nutritional biology remain poorly understood. The anterior salivary glands (ASG), posterior salivary glands (PSG), and digestive gland (DG) are central to these processes, but molecular comparisons are lacking. To address this gap, we performed a transcriptomic study to explore the enzymatic repertoire and functional specialization of these tissues. Total RNA was extracted from ASG, PSG, and DG of three pre-adult individuals collected in La Paz Bay, Mexico. RNA-Seq libraries were sequenced, and a non-redundant multi-tissue transcriptome was assembled. The ASG displayed high expression of neuropeptides, playing a role in neuroendocrine regulation. The PSG showed elevated protease expression, supporting its function in extracellular digestion, alongside toxins that reinforce its role as a venom gland. The DG was enriched in proteins linked to biomolecule catabolism and antimicrobial peptides, alluding to metabolic specialization and immune defense. These results were validated by qPCR, and target genes were also amplified in Octopus maya and O. hubbsorum, showing some similarities in expression patterns. Overall, our findings suggest strong glandular specialization in P. digueti, providing insights into cephalopod digestive physiology and supporting its value as a model species. Full article

The gut microbiota of Drosophila melanogaster offers a simplified yet powerful system to study conserved mechanisms of host–microbe interactions. Unlike the highly complex mammalian gut microbiota, which includes hundreds of species, the fly gut harbors a small and defined community dominated by Lactobacillus and Acetobacter. Despite its low diversity, this microbiota exerts profound effects on host physiology. Commensal bacteria modulate nutrient acquisition, regulate insulin/TOR signaling, and buffer dietary imbalances to support metabolic homeostasis and growth. They also influence neural and behavioral traits, including feeding preferences, mating, and aggression, through microbial metabolites and interactions with host signaling pathways. At the immune level, microbial molecules such as peptidoglycan, acetate, uracil, and cyclic dinucleotides activate conserved pathways including Imd, Toll, DUOX, and STING, balancing antimicrobial defense with tolerance to commensals. Dysbiosis disrupts this equilibrium, accelerating aging, impairing tissue repair, and contributing to tumorigenesis. Research in Drosophila demonstrates how a low-diversity microbiota can shape systemic host biology, offering mechanistic insights relevant to human health and disease. Full article

The proteasome is a central proteolytic complex that maintains protein homeostasis by eliminating damaged, misfolded, and regulatory proteins. Beyond this quality control role, it generates bioactive peptides that contribute to immune surveillance, intracellular signaling, neuronal communication, and antimicrobial defense. Proteolysis is mediated by the catalytic β1, β2, and β5 subunits, traditionally defined by caspase-like, trypsin-like, and chymotrypsin-like activities. However, these sites display overlapping and flexible specificities, enabling cleavage after nearly all amino acids. This review focuses on proteasome catalytic activity, with particular emphasis on the biochemical and structural features of the catalytic subunits that define cleavage selectivity. We first provide a historical overview of the discovery of proteolytic activities and trace the evolutionary diversification of subunits that gave rise to specialized variants such as the immunoproteasome, thymoproteasome, intermediate proteasomes, and the spermatoproteasome. We then highlight how advances in computational modeling and structural biology have refined our understanding of cleavage preferences. In addition, we examine how regulatory particles, post-translational modifications, and physiological conditions, including inflammation, oxidative stress, and aging, modulate proteolytic activity. Finally, we discuss the development of selective inhibitors targeting individual catalytic sites, emphasizing their therapeutic potential in cancer, autoimmunity, and infectious disease, and outline future directions for the field. Full article

CRISPR-Cas systems are best known as adaptive immune defenses in prokaryotes, but they also function as versatile regulators bridging bacterial immunity with host-related processes. Beyond neutralizing invasive phages and plasmids, these systems influence core aspects of bacterial physiology, such as modulating gene expression, stress responses, biofilm formation, quorum sensing, and virulence. Notably, CRISPR-mediated regulation can facilitate immune evasion at the host-pathogen interface, underscoring these systems as central orchestrators of microbial survival and host interactions. In addition, CRISPR-Cas has rapidly become a cornerstone of synthetic biology and microbiome engineering. Recent strategies repurpose native and engineered CRISPR systems to precisely modulate microbiome composition or deliver sequence-specific antimicrobials, underscoring the expanding translational potential of this system. Collectively, emerging insights highlight both the canonical immune function and non-canonical regulatory roles of CRISPR-Cas, as well as their broad biological and biotechnological relevance. This review provides a critical synthesis of these developments, illustrating how CRISPR-Cas bridges adaptive immunity and microbial physiology, and outlines future directions for harnessing this duality to deepen understanding of microbial physiology and inform new translational applications. Full article

Chemerin, encoded by the RARRES2 gene, is an adipokine with potent immunometabolic functions mediated through CMKLR1, GPR1, and CCRL2. Its regulation is tissue- and context-dependent, conferring dual protective and pathogenic roles. In the upper GI tract, chemerin facilitates immune tolerance in Barrett’s adenocarcinoma and promotes invasion in esophageal and gastric cancers. In pancreatic disease, it acts as a biomarker of acute and chronic injury, while modulating β-cell function and carcinogenesis. In the liver, chemerin contributes to NAFLD/NASH pathogenesis with both anti-inflammatory and pro-steatotic actions, predicts prognosis in cirrhosis, and demonstrates tumor-suppressive potential in hepatocellular carcinoma. In IBD, chemerin exacerbates colitis via impaired macrophage polarization, yet protects epithelial antimicrobial defense, underscoring its context-specific biology. Collectively, these findings position chemerin as a versatile regulator bridging metabolic dysfunction, inflammation, and gastrointestinal malignancy, and as a potential candidate for biomarker development and therapeutic intervention. Full article

Cyclic lipopeptides (CLPs), produced by beneficial rhizobacteria such as Bacillus and Pseudomonas species, are specialized metabolites retaining key functions for the plant protective activity of the producers, which shows their potential as biocontrol agents in agriculture. Beyond their strong antimicrobial properties, CLPs can act as potent elicitors of plant immunity and systemic resistance. However, the molecular mechanisms underlying these immune-modulatory effects and the role of CLPs’ structural diversity remain poorly understood. Here, we demonstrate that specific structural features of surfactin-type CLPs critically influence their ability to trigger early immune responses in plants, including reactive oxygen species bursts, nitric oxide (NO) production, calcium fluxes, and systemic resistance. In Arabidopsis thaliana roots, we show that surfactin-induced NO generation requires calcium signaling. Moreover, we reveal that contrasting immune effects of CLPs may stem from the ecological lifestyles of their microbial producers, shedding light on the evolutionary basis of plant–microbe interactions. Altogether, our findings underscore the importance of CLP structural variation in shaping plant defense responses and highlight the potential for structure-informed design of next-generation biosourced small molecules with broad-spectrum efficacy as plant protectants. Full article

Campylobacter hepaticus is the etiological agent of Spotty Liver Disease (SLD), a newly emerging bacterial disease of laying hens resulting in significant mortality and production losses primarily in free-range systems. Although its economic impact continues to grow, the molecular basis of C. hepaticus pathogenesis remains poorly understood. In this study, we conducted transcriptomic profiling of C. hepaticus in three host-relevant conditions, exposure to chicken bile, infection of a chicken liver hepatocellular carcinoma (LMH) cell line, and isolation from liver lesions of naturally infected chickens. Through RNA-seq analysis, we found unique gene expression signatures in each environment. In the bile, C. hepaticus exhibited differential expression of 412 genes, with upregulation of genes related to motility, cell envelope remodeling, glycosylation, nitrate respiration, and multidrug efflux systems, indicating a stress-adaptive, metabolically active lifestyle. In LMH, on the other hand, 125 genes were differentially expressed, primarily reflecting downregulation of motility, oxidative stress response, chaperones, and core metabolic processes, suggesting that these cells adopt a less active, intracellular dormant lifestyle. Transcriptomic analysis of C. hepaticus isolated from the liver identified 26 differentially expressed genes, featuring selective upregulation of genes associated with nitrate respiration, sulfur metabolism, and pyridoxal 5’ phosphate homeostasis, alongside downregulation of the major outer membrane porin (momp), stress response chaperones (dnaK, groL), and genes involved in oxidative stress defense and energy production. Furthermore, the immune evasion-related gene cmeA and a glycosyltransferase gene were found to be highly upregulated. This study presents the first in-depth transcriptomic exploration of C. hepaticus in multiple host relevant niches. Our findings reveal niche-specific gene expression profiles and highlight metabolic and structural adaptations that enable C. hepaticus to survive during bile exposure, persist within host cells, and contribute to liver pathology. These insights provide a basis for identifying novel virulence determinants and may inform the development of targeted interventions, including vaccines or antimicrobial therapy, to control SLD in commercial poultry operations. Full article

This study investigated the protective effect of fermented milk by Lacticaseibacillus rhamnosus D1 in a murine model of Typhoid fever, focusing on cytokines, antimicrobial peptides and microbiota modulation. BALB/c mice were pre-treated with milk fermented by L. rhamnosus D1 prior to Salmonella Typhimurium challenge. Outcomes assessed included survival, weight change, bacterial translocation, mRNA expression of cytokines and antimicrobial peptides, in addition to gut microbiota modulation. Mice receiving fermented milk exhibited higher survival rates, reduced bacterial translocation and attenuated weight loss compared to controls. mRNA expression analyses revealed that L. rhamnosus D1 pre-treatment suppressed the expression of pro-inflammatory cytokines (IFN-γ, IL-6 and IL-12) and upregulated anti-inflammatory cytokines (IL-5, IL-10 and TGF-β), as well as antimicrobial peptides (Reg3β, Reg3γ and Lcn2). Furthermore, we observed that the consumption of fermented milk changed the gut microbiota of infected mice, not only by modulating the existing taxa, but also by facilitating the emergence of unique, potentially beneficial microbial lineages, such as Muribaculum, Roseburia, Intestinimonas, Bdellovibrio and Facklamia. These findings indicate that L. rhamnosus D1 protected mice against S. Typhimurium infection through immunomodulatory and microbiota-mediated mechanisms, changing mucosal immunity and strengthening the intestinal barrier by modulating gut microbiota and immune responses, in addition to promoting host antimicrobial defenses. Full article

Antimicrobial resistance (AMR) is a growing global threat, exacerbated by the adaptive mechanisms of Gram-negative ESKAPE pathogens, which include biofilm formation and outer membrane vesicle (OMV) production. Biofilms create robust protective barriers that shield bacterial communities from immune responses and antibiotic treatments, while OMVs contribute to both defense and offense by carrying antibiotic-degrading enzymes and delivering virulence factors to host cells. These mechanisms not only enhance bacterial survival but also increase the virulence and persistence of infections, making them a significant concern in clinical settings. This review explores the molecular processes that drive biofilm and OMV formation, emphasizing their critical roles in the development of AMR. By understanding these mechanisms, new therapeutic strategies can be developed to disrupt these defenses, potentially improving the efficacy of existing antibiotics and slowing the spread of resistance. Additionally, the use of OMVs in vaccine development and drug delivery offers promising avenues for future research. Addressing these challenges requires a comprehensive approach, combining advanced research with innovative therapies to combat the escalating threat of AMR and improve patient outcomes. Full article

Defensins are a class of small cysteine-rich cationic antimicrobial peptides (AMPs) that play vital roles in immune-regulating insect–microbe interaction, offering great potential for developing pest control approaches using RNA interference (RNAi) and insect pathogens. However, the biocontrol potential of defensins from the destructive rice pest Nilaparvata lugens (brown planthopper, BPH) remains largely unexplored. Here, we identified and functionally characterized a defensin-encoding gene NldefB in BPH. The open reading frame (ORF) of NldefB is 315 bp in length, encoding 104 amino acids with a conserved Knot1 domain. The qRT-PCR results showed that the transcription level of NldefB went upward with the increasing developmental stages, with the highest expressions in the female adults and their fat body. The expression of NldefB was continuously induced by bacterial pathogens but exhibited a pattern of initial increase followed by a decrease when challenged by a fungal pathogen Metarhizium anisopliae. RNAi-mediated silencing of NldefB significantly decreased the host survival rate, egg production and hatchability, as well as the capability to resist fungal infection. Additionally, NldefB suppression resulted in a significant increase in microbial loads. Our findings underscored that NldefB plays essential roles in regulating host development, pathogen defense, and microbial maintenance, providing a potential target for RNAi- and microbe-mediated BPH biocontrol. Full article

The increasing demand for sustainable agriculture has accelerated research into eco-friendly plant health management, particularly through natural substances rich in bioactive compounds. In this study, various substances, including essential oils, extracts from Aloe vera, artichoke and ornamental plants, by-products from beer and coffee processing, and selected commercial formulations including biostimulants and a plant strengthener, were evaluated for their antimicrobial properties and ability to trigger plant defenses. Notably, Agapanthus spp. exhibited strong antifungal activity against the fungus Botrytis cinerea (Bc), while thyme, tea tree, and lavender essential oils were effective against both Bc and the bacterium Pseudomonas syringae pv. tomato (Pst). Greenhouse trials on tomato plants demonstrated the protective effects of A. vera gel and ornamental plant extracts against Bc and Potato virus Y (PVY), while coffee and artichoke extracts were effective against Pst. An alginate-based formulation containing thyme oil showed enhanced in planta efficacy against the three pathogens. Gene expression analyses revealed early upregulation of PR-1 and PR-4, especially with alginate treatments and A. vera gel at 12 h post-treatment (hpt) while coffee extract triggered the strongest late response at 72 hpt. These findings highlight the potential of plant-derived substances in promoting sustainable plant disease management through both direct antimicrobial action and immune system activation. Full article

Breastfeeding is a complex biological system and a bidirectional physiological dialogue in which the infant may contribute to maternal breast health. This review synthesizes current evidence, clearly separating established findings from emerging hypotheses, to examine the possible infant-driven mechanisms that influence hormonal and immune homeostasis in the mammary gland. We evaluate how neonatal suckling coordinates interconnected hormonal reflexes and immune activity, and we explore the hypothesis that the retrograde flow of infant saliva to the breast tissue could activate maternal enzymatic defenses, particularly the xanthine oxidase and lactoperoxidase systems. We also consider the activation of antimicrobial peptides through direct contact at the nipple and areola, including cathelicidin and defensins, as well as the potential roles of fetal microchimerism and microbial transfer from the infant’s mouth in strengthening breast resilience. Although much of the evidence remains indirect and based on in vitro and animal models, the convergence of data supports a reformulated conceptual model that presents the infant as an active physiological partner rather than a passive recipient of milk. Recognizing this shift has important clinical implications for the prevention of inflammatory conditions such as mastitis, the improvement of breastfeeding support strategies, and the optimization of maternal and infant health outcomes. The review also identifies significant gaps in current knowledge and cautiously proposes hypotheses to explore these mechanisms. While preliminary, this framework offers an original perspective that may guide future research and open new paths in the study of human lactation biology. Full article

The common bean (Phaseolus vulgaris L.) is a vital food crop worldwide, particularly in Latin America, Asia, and Sub-Saharan Africa, due to its high levels of protein, fiber, and essential nutrients. However, it is susceptible to viral infections, especially from the Bean common mosaic virus and Bean common mosaic necrosis virus. While previous research has primarily focused on specific resistance genes, a broader understanding of the plant’s overall immune response remains limited. To investigate this, a study was conducted involving 51 infected leaf samples. RNA was extracted, and deep metatranscriptomic sequencing was performed using the Illumina MiSeq platform. The results indicated that several genes related to stress response, nitrogen metabolism, and biosynthesis pathways were activated during infection. Key defense mechanisms included pathogen recognition, the production of antimicrobial peptides, and changes in metabolic activity. The Mitogen-Activated Protein Kinase (MAPK) signaling pathway and enzymes like glycosyl transferases, which aid in building protective structures, played a significant role. These findings suggest that the bean’s defense system is complex and involves not only direct attacks on pathogens but also metabolic shifts and microbial interactions. Understanding these processes provides valuable insights for breeding stronger, disease-resistant, and climate-resilient bean varieties. Full article