Search Results (326)

Background: The interaction between probiotics and the vitamin D/vitamin D receptor (VDR) pathway has been increasingly explored as a potential mechanism for immune modulation in inflammatory bowel disease (IBD). Lactobacillus rhamnosus GG (LGG) has shown promising results in ulcerative colitis (UC) patients, but its effect on the VDR pathway remains unexplored in humans. Aim: To test the hypothesis that LGG can stimulate the vitamin D/VDR pathway and modulate mucosal-adherent microbiota. Methods: In this study, we analyzed a subgroup of 13 patients from the LGGinUC trial, in which UC patients with mild-to-moderate disease activity received LGG monotherapy for four weeks. Colonic biopsy samples were collected before and after treatment to evaluate VDR expression via RT-qPCR and immunohistochemistry. Mucosal-adherent microbiota was also analyzed by DNA extraction and next-generation sequencing (NGS). Results: LGG administration significantly increased VDR mRNA expression in colonic mucosa (p < 0.05), with a corresponding rise in VDR protein levels in both epithelial and sub-epithelial compartments. Microbiota analysis revealed a reduction in α-diversity, primarily due to a decrease in commensal bacterial species, while β-diversity remained largely unchanged. Conclusions: Although the present results have to be considered preliminary, this is the first human study demonstrating that probiotic supplementation can upregulate VDR expression in colonic mucosa. We propose that LGG may exert its beneficial effects in UC by stimulating the VDR pathway, which in turn modulates mucosal immunity and microbiota composition. Further studies with larger sample sizes and longer treatment durations are needed to validate these findings and explore their therapeutic implications. 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

Alternaria brown spot is an important fungal disease in citrus. The infection of young citrus organs usually coincides with strong rainfall, which causes low efficiency of fungicides and the outbreak of this disease. Here, the microbiomes of the asymptomatic peels, the spot edge, and the center of citrus fruits were compared to reveal the commensal microbes as alternative control methods for the Alternaria pathogen. As the disease severity increased from the asymptomatic peels to the spot edge and the center, the bacterial communities were more severely changed than the fungal communities. Both the bacterial diversity, represented by the Shannon diversity index, and the bacterial composition and structure significantly decreased and altered, respectively. Increased Alternaria, in relative abundance, correlated positively with bacterial genera like Massilia and Sphingomonas, while negatively correlating with bacterial genera like Delftia and Pantoea. In addition, Alternaria fASV1 positively correlated with several top ASVs of 1174_901_12 and Sphingomonas. These results suggest that the bacterial communities respond to Alternaria brown spot by Alternaria–bacteria cross-kingdom interactions; these responsive bacteria are worth testing experimentally. Full article

It is known that the giant barrel sponge (GBS) Xestospongia spp. may provide shelter or a micro-environment for multi-species coral colonies both in the Indo-Pacific and Atlantic regions. An assessment of such interactions between Indo-Pacific GBS Xestospongia testudinaria and stony corals performed for two groups of small Vietnamese islands in the Gulf of Thailand revealed at least 12 species of scleractinians associated with GBS. An average of 21.7% of all observed GBSs were found to interact with stony corals. The phenomenon of positive GBS–coral interactions without any restrictions on coral development can be regarded as a form of ecological facultative commensalism and warrants further investigation. Full article

Fungal communities in the gut influence host immunity, yet most studies have focused on cell wall components rather than genetic materials. Here, we explore how fungal genomic DNA (gDNA) from Candida albicans, Saccharomyces cerevisiae, and Cryptococcus neoformans modulate immune responses in human CD4⁺ T cells, murine splenocytes, and THP-1-derived macrophages. We find that C. albicans gDNA promotes the development of regulatory T cells and increases IL-10, fostering immune tolerance and preserving CD4⁺ T cell viability in an inflammatory setting. S. cerevisiae gDNA induces moderate Treg responses with restrained effector T cell expansion and higher checkpoint gene expression, entirely consistent with its commensal nature. In contrast, C. neoformans gDNA elicits a strongly inflammatory profile, promoting Th1/Th17 cells and driving high cytokine production. Mechanistically, C. albicans and S. cerevisiae gDNA dampen DNA-sensing pathways and enhance immune checkpoint molecules that act as brakes against overactivation, while C. neoformans gDNA robustly activates innate sensing pathways with limited checkpoint induction. These species-specific signaling profiles reveal that fungal gDNA itself can influence whether the immune system adopts a tolerant or inflammatory response toward fungi. This discovery highlights fungal genomic DNA as a previously underappreciated regulator of host–fungus interactions, offering new insight into commensal persistence, pathogenic invasion, and the potential for DNA-based antifungal interventions. Full article

Immune checkpoint inhibitors (ICIs) have radically changed the landscape of systemic treatment for hepatocellular carcinoma (HCC). Recently, there has been increasing interest regarding the relationship between the gut microbiome and the response to immunotherapy in oncological treatments. Among the gut commensals, Akkermansia (A.) muciniphila has gained increasing attention in the literature. A. muciniphila may affect the tumor microenvironment and enhance the efficacy of systemic therapies, including ICIs and targeted agents, by shaping host immune responses and metabolic pathways. This narrative review summarizes the current knowledge on A. muciniphila and its potential interaction with systemic therapies for HCC, focusing on its immunostimulatory properties, including enhancement of cytotoxic CD8⁺ T-cell activity and reversal of immunosuppressive tumor microenvironments. The therapeutic role of A. muciniphila might represent a novel and promising weapon in the HCC field, although the road is still long and the scientific evidence still remains in an exploratory stage. Its integration into clinical practice, however, requires robust clinical trials and a deeper understanding of its interactions within the gut–liver axis and tumor ecosystem. Full article

Hidradenitis suppurativa (HS) is a chronic, recurrent, and highly debilitating inflammatory disorder of the pilosebaceous unit. Its pathogenesis is considered multifactorial, involving genetic, environmental, hormonal, lifestyle, and microbiome-related factors. The microbiota, defined as the collection of microorganisms, their genomes, and their interactions within a given environment, colonizes multiple sites of the healthy human body, which include the skin and gut, where it contributes to the maintenance of homeostasis. In HS, both skin and gut microbiota exhibit disruptions in composition and diversity, a state referred to as dysbiosis. Alterations in the expression of antimicrobial peptides in HS further implicate the microbiome in disease pathophysiology. In addition, chronic inflammation, bacterial biofilm formation, and dysbiosis are thought to contribute to the severity and recurrence of HS. Although the precise role of dysbiosis in HS pathogenesis remains unclear, several studies have demonstrated a reduction in cutaneous microbial diversity in HS patients, distinguished by an increased abundance of anaerobic and opportunistic bacteria and a reduction in commensal species. The intestinal microbiome has been even less thoroughly investigated, but available evidence suggests decreased overall diversity and richness, with enrichment of pro-inflammatory and depletion of anti-inflammatory bacterial taxa. This review aims to provide an overview of the current knowledge regarding the role of the microbiome in HS, with the goal of informing the direction of future research, including the potential utility of the microbiome as a biomarker for diagnosis and severity stratification in HS. Full article

Breast cancer is one of the most frequently diagnosed malignancies and remains the leading cause of cancer-related death among women worldwide. Emerging evidence implicates the microbiota to be a potential contributor to its pathogenesis and progression. This review summarizes emerging evidence of microbial alterations across various body niches in breast cancer patients, including gut, breast tissue, nipple aspirate fluid (NAF), oral cavity, skin, urinary and reproductive tracts, and blood. Reductions in commensal taxa such as Faecalibacterium, Bifidobacterium, Lachnospira, Akkermansia, and Sphingomonas, along with an increase in pro-inflammatory genera like Prevotella, Fusobacterium, and Desulfovibrio, may promote breast tumor development and progression through multiple pathways including modulation of estrogen metabolism, production of microbial metabolites, and immunoregulation. The presence of cross-niche overlaps and possible translocation of microbiota between niches through the bloodstream suggests the existence of a complex interconnected oral–gut–breast microbiota axis. Progress in the field will depend on integrative multi-omics, translational approaches, and longitudinal studies to give a clearer mechanistic understanding of microbiota–host interactions to develop feasible microbiota-based biomarkers and therapeutic strategies in breast cancer. Full article

The ocular surface microbiome consists of microorganisms that play an important role in maintaining homeostasis and preventing disease from invading pathogens. Commensal microbes on the ocular surface interact with cells and molecules of the ocular surface immune system to promote immune tolerance to the normal flora of the ocular surface and facilitate immune protection against invading pathogenic microbes, which allows for a disease-free ocular surface. Various factors can impact the composition, distribution, and diversity of the ocular surface microbiome, including age, gender, disease state, antibiotic treatment, and contact lens use. In addition, there is no cohesive consensus on the species that make up the ocular surface microbes. There is, however, thorough research present on other similar mucosal membranes, such as the gut and oral mucosa, that share similarities with the ocular mucosa. Exploring the relationship of different mucosae allows us to explore treatment options for common ocular diseases such as dry eye syndrome. This review highlights studies that define the ocular surface microbiome, its diversity and composition, host–immune interactions at the ocular surface, factors that cause dysbiosis of the ocular surface microbiome, the impact of dysbiosis on the ocular surface microbiome, and microbiome-based therapy. Full article

Norovirus–bacterial interactions influence viral replication and immune responses, yet the molecular details that mediate binding of these viruses to commensal bacteria are unknown. Studies with other enteric viruses have revealed that LPS and other lipid/carbohydrate structures facilitate virus–bacterial interactions, and it has also been shown that human noroviruses (HuNoVs) can interact with histo-blood group antigen (HBGA)-like compounds on the surface of bacterial cells. Based on these findings, this study hypothesized that carbohydrate-based compounds were the ligands that facilitated binding of both human and murine noroviruses (MNV) to bacteria. Using glycan microarrays, competitive inhibition assays, and a panel of bacterial mutants, the project assessed the influence of specific glycans on viral attachment to bacteria. Protein-based interactions were also examined. The results supported previous work which demonstrated that HuNoVs strongly bind HBGA-like glycans, while MNV displayed distinct binding to other glycans including aminoglycosides and fucosylated structures. Ultimately, this work demonstrates that HuNoVs have more limited binding requirements for bacterial attachment compared to MNV, and the MNV binding to bacteria may involve both specific structures as well as electrostatic interactions. Given the importance of commensal bacteria during viral infection, defining the molecular mechanisms that mediate virus–bacteria interactions is critical for understanding infection dynamics and may be useful in the development of disease therapeutics and novel technologies for viral detection from food and environmental sources. Full article

Helminths that inhabit the gastrointestinal (GI) tract represent some of the most significant infectious agents impacting health. The interaction between the human microbiota, GI helminths, and their host occurs through multiple complex pathways, altering the host’s immune system and the dynamics of the commensal gut microbiota (GM). These interactions also largely influence a balanced state of homeostasis and health promotion and robustly activate the immune system, facilitating tumor eradication and mitigating the challenges of drug resistance. Furthermore, incorporating microbial metabolites into radiotherapy and chemotherapy reduces the intense adverse effects of these treatments while enhancing their overall effectiveness. The interplay between GM and helminths, as well as their metabolites, significantly impacts the development, prognosis, and treatment of cancer. The interaction mechanisms between GI helminths and the GM are not fully elucidated. Thus, understanding a beneficial biological relationship can reveal hidden mechanisms for controlling and inhibiting cancer pathways in humans by providing insights into cellular processes and potential therapeutic targets. This knowledge can be applied to develop more effective cancer treatments. This review outlines the existing research on GM metabolites in cancer, intending to offer innovative pathways for future cancer treatment. Full article

Using metrics from network theory allows us to understand the structural organization of epiphyte communities and identify the host trees (phorophytes) that are fundamental to their establishment. In this study, we applied ecological network metrics to examine the structure of interactions between vascular epiphytes and phorophytes in a woody inselberg community in southeastern Brazil. The recorded network comprised 30 epiphyte species and 13 phorophyte species, exhibiting a nested structure, low specialization (H₂′), low connectance, and low modularity, like other epiphyte–phorophyte networks. The main roles in the network were played by the generalist epiphyte Tillandsia loliacea and the lithophytic phorophytes Tabebuia reticulata and Pseudobombax petropolitanum, which interacted with 100% of the recorded epiphytic species. Epiphyte species were organized vertically into modules that correlate with the ecological zones of the phorophytes, suggesting that their distribution responds to microclimatic variation along the vertical gradient. These results reinforce the importance of particular phorophyte species as key structuring agents of epiphytic communities and highlight their central role in extreme environments such as inselbergs. Full article

Highly pathogenic avian influenza (HPAI) remains a persistent threat to global poultry production and public health. Current vaccine platforms show limited cross-clade efficacy and often fail to induce mucosal immunity. Recent advances in microbiome research reveal critical roles for gut commensals in modulating vaccine-induced immunity, including enhancement of mucosal IgA production, CD8⁺ T-cell activation, and modulation of systemic immune responses. Engineered commensal bacteria such as Lactococcus lactis, Bacteroides ovatus, Bacillus subtilis, and Staphylococcus epidermidis have emerged as promising live vectors for antigen delivery. Postbiotic and synbiotic strategies further enhance protective efficacy through targeted modulation of the gut microbiota. Additionally, artificial intelligence (AI)-driven tools enable predictive modeling of host–microbiome interactions, antigen design optimization, and early detection of viral antigenic drift. These integrative technologies offer a new framework for mucosal, broadly protective, and field-deployable vaccines for HPAI control. However, species-specific microbiome variation, ecological safety concerns, and scalable manufacturing remain critical challenges. This review synthesizes emerging evidence on microbiome–immune crosstalk, commensal vector platforms, and AI-enhanced vaccine development, emphasizing the urgent need for One Health integration to mitigate zoonotic adaptation and pandemic emergence. Full article

Polymicrobial biofilms involving fungal and bacterial species are increasingly recognized as contributors to persistent infections, particularly in the oral cavity. Candida albicans and Aggregatibacter actinomycetemcomitans are two commensals that can turn into opportunistic pathogens and are able to form robust biofilms. Objectives: This study aimed to assess the interaction dynamics between these two microorganisms and to evaluate their susceptibility to fluconazole and azithromycin in single- and mixed-species forms. Methods: Biofilm biomass was quantified using crystal violet assays, while biofilm cell viability was assessed through CFU enumeration (biofilm viability assay). To assess the resistance properties of single versus mixed-species coincubations, we applied the antimicrobial susceptibility test (AST) to each drug, and analysed spatial organization with confocal laser scanning microscopy, using PNA-FISH. Results: The results indicated that both species can coexist without significant mutual inhibition. However, a non-reciprocal synergism was also observed, whereby mixed-species biofilm conditions promoted the growth of A. actinomycetemcomitans, while C. albicans growth remained stable. As expected, antimicrobial tolerance was elevated in mixed cultures, likely due to enhanced extracellular matrix production and potential quorum-sensing interactions, contributing to increased resistance against azithromycin and fluconazole. Conclusions: This study provides novel insights into previously rarely explored interactions between C. albicans and A. actinomycetemcomitans. These findings underscore the importance of investigating interspecies interactions within polymicrobial biofilms, as understanding their mechanisms, such as quorum-sensing molecules and metabolic cooperation, can contribute to improved diagnostics and more effective targeted therapeutic strategies against polymicrobial infections. Full article

Konjac glucomannan (KGM) is a natural polysaccharide polymer. It is degraded by gut microbiota-derived β-mannanase into small-molecule nutrients, which exert diverse physiological regulatory effects. As a prebiotic, KGM modulates gut microbiota composition. It selectively fosters the proliferation of beneficial commensals and suppresses potential pathogens, thereby alleviating microbiota-related disorders. Moreover, microbiota fermentation of KGM produces metabolites. Short-chain fatty acids (SCFAs) are particularly notable among these metabolites. They exert multifaceted beneficial effects, including metabolic regulation, intestinal barrier strengthening, and neuroprotective functions. These effects are mediated through inhibition of inflammatory pathways (e.g., NF-κB, MAPK), modulation of lipid metabolism genes (e.g., CD36), and regulation of neurotransmitters (e.g., GABA, 5-HT). This highlights KGM’s therapeutic potential for metabolic, inflammatory, and neurodegenerative diseases. Current clinical use is limited by dose-dependent adverse effects and interindividual response variability, which stem from different microbial communities. This necessitates personalized dosage strategies. Despite these limitations, KGM as a prebiotic polysaccharide exhibits multifaceted bioactivity. Current evidence suggests its potential to synergistically modulate metabolic pathways, gut microbiota composition, immune cell signaling, and neuroendocrine interactions. This highlights its promise for developing novel therapeutic interventions. Full article