The mucus and mucins of the goblet cells and enterocytes provide the first defense line of the gastrointestinal tract and interact with the immune system

Listeria monocytogenes gut interactions and listeriosis: Gut modulation and pathogenicity

Following ingestion via contaminated food, Listeria monocytogenes faces multiple hurdles through the human digestive system, thereby influencing its capacity to cause infection. This review provides a comprehensive overview of the multifaceted mechanisms employed by L. monocytogenes to overcome gastrointestinal hurdles and interact with the host's microbiota, facing chemical and physical barriers such as saliva, stomach acidity, bile salts and mechanical clearance. Proposed evasion strategies will be highlighted, exploring the bacteriocins produced by L. monocytogenes, such as the well-described bacteriocin Listeriolysin S (LLS), a bacteriocin that inhibits inflammogenic species - Lmo2776, and a phage tail-like bacteriocin, monocin. The competitive dynamic interactions within the gut microbiota, as well as the modulation of microbiota composition and immune responses, will also be explored. Finally, the adhesion and invasion of the intestinal epithelium by L. monocytogenes is described, exploring the mechanism of pathogenesis, biofilm and aggregation capacities and other virulence factors. Unlike previous reviews that may focus on individual aspects of L. monocytogenes pathogenicity, this review offers a holistic perspective on the bacterium's ability to persist and cause infection, integrating information about survival strategies, including bacteriocin production, immune modulation, and virulence factors. By connecting recent findings on microbial interactions and infection dynamics, this review incorporates recent developments in the field and connects various lines of research that explore both host and microbial factors influencing infection outcomes.

Effect of hypoxia on the mucus system and intragastric microecology in the gastrointestinal tract

Digestive diseases have a high incidence worldwide, with various geographic, age, and gender factors influencing the occurrence and development of the diseases. The main etiologic factors involve genetics, environment, lifestyle, and dietary habits. In a low-oxygen environment, however, the body's tissue cells activate hypoxia-inducible factor (HIF), which produces different inflammatory mediators. Hypoxia impacts health at the molecular level by modulating cellular stress responses, metabolic pathways, and immune functions. It also alters gene expression and cellular behavior, thereby affecting gastrointestinal function. Under normal physiological conditions, the gastrointestinal mucus system serves as a crucial protective barrier, defending against mechanical injury, pathogenic invasion, and exposure to harmful chemicals. The integrity and functionality of this barrier are dependent on the synthesis and regulation of mucins and mucus, which are influenced by multiple factors. Additionally, the composition and diversity of the gastric microbiota are shaped by factors such as Helicobacter pylori infection, diet, and lifestyle. A balanced gastric microbiota supports gastrointestinal health and fortifies the mucus barrier. However, hypoxia can disrupt this equilibrium, leading to inflammation, alterations in the mucus layer, and destabilization of the gastric microbiota. Understanding the interplay between hypoxia, the mucus system, and the gastric microbiota is essential for identifying novel therapeutic strategies. Future research should elucidate the mechanisms through which hypoxia influences these systems and develop interventions to mitigate its adverse effects on gastrointestinal health. We examined the impact of hypoxia on the gastrointestinal mucus system and gastric microbiota, highlighting its implications for human health and potential therapeutic approaches.

Crataegus pinnatifida polysaccharide alleviates DSS-induced colitis in mice by regulating the intestinal microbiota and enhancing arginine biosynthesis

BACKGROUND

The development of effective and safe dietary supplements is essential for both the prevention and management of ulcerative colitis (UC), as its pathogenesis is intricate and difficult to completely resolve. Crataegus pinnatifida, a medicinal food with a long history of use, has broad medicinal value. Recent research has revealed promising insights into the role of polysaccharide derived from Crataegus pinnatifida on modulating short-chain fatty acids (SCFAs) to alleviate UC inflammation. However, the mechanisms by which CPP regulates the intestinal microbiota and key metabolites during the antagonistic phase of UC have yet to be elucidated.

OBJECTIVE

This research elucidated the protective role of CPP in relation to UC, highlighted the mechanisms through which CPP operates, particularly regarding gut microbiota and metabolism, and offered a theoretical foundation for the potential use of CPP as a dietary supplement aimed at preventing UC.

METHODS

The impact of CPP on acute UC induced by 3 % DSS in mice was examined through the evaluation of the disease activity index, measurement of colon length, and observation of body weight changes. Enzyme-linked immunosorbent assay (ELISA) was used to measure inflammatory factor levels in both serum and colon, as well as to assess oxidative stress mediators. The intestinal histological damage, mucus layer damage and the level of tight junction protein were analyzed by histopathological staining and western blot (WB). The impact of gut microbiota on CPP in colitis was evaluated using 16S rRNA sequencing, microbiota depletion experiments, and fecal microbiota transplantation (FMT) studies. The key metabolic pathways and key metabolites affected by CPP in the treatment of UC were analyzed through untargeted metabolomics sequencing, ELISA, and WB assays.

RESULTS

Prophylactic dietary supplementation with Crataegus pinnatifida polysaccharide (CPP) notably reduced the fundamental clinical manifestations of UC induced by DSS, including DAI score, reduced colon length, and weight loss, as well as inflammation and oxidative stress. CPP promoted the expression of Claudin-1, ZO-1 and Occludin and promoted mucin secretion, which contributed to the mitigation of intestinal barrier damage caused by DSS. 16S sequencing results and metabolomics results revealed that CPP intervention upregulated the relative abundance of Lactobacillus, thereby reshaping the intestinal microbiota and activate the arginine biosynthesis pathway. The results of fecal microbiota transplantation and antibiotic clearance experiments indicated that the alleviating effect of CPP on UC was dependent on the intestinal microbiota and this alleviating effect was transferred through fecal microbiota transplantation. Mechanistically, CPP indirectly promoted the expression of the rate-limiting enzyme argininosuccinate synthase 1 (ASS1) in the intestinal Arginine biosynthesis pathway by reshaping the intestinal microbiota, thereby increasing intestinal Arginine level and alleviating the inflammatory response and oxidative stress induced by DSS and intestinal barrier damage.

CONCLUSION

Our research findings demonstrate that CPP is a plant-derived polysaccharide that alleviates UC by modulating the gut microbiota and enhancing arginine biosynthesis.

The stomach, small intestine, and colon-specific gastrointestinal tract delivery systems for bioactive nutrients

Oral administration is a convenient way to deliver bioactive nutrients. However, the complex and dynamic environment of the gastrointestinal (GI) tract poses distinct challenges. These include the acidic environment of the stomach, limited transport across the GI mucosa, and the risk of enzymatic degradation, all of which can compromise the nutritional effectiveness of orally delivered nutrients. In response to these challenges, various GI tract delivery systems have been developed to target specific regions, such as the stomach, small intestine, or colon, to precisely control the release of bioactive nutrients and enhance their health-promoting benefits. This review critically examines the principles underlying stomach-, small intestine-, and colon-targeted delivery systems, highlighting the selection of appropriate wall materials and the interactions between delivery systems and the mucosal epithelial barrier. Moreover, we describe relevant biological models and quantitative analyses to measure these interactions. In particular, we emphasize the significant advantages offered by colon-targeted delivery systems in maintaining a healthy colonic microenvironment. This review aims to inspire novel concepts and stimulate further research into GI tract delivery systems, offering promising avenues for maximizing the therapeutic effects of bioactive nutrients in practical applications.

Restoration of gut integrity by Bacteroides acidifaciens in water-deprived conditions

Water scarcity exerts profound physiological impacts, yet its effects on intestinal microbiota-barrier crosstalk remain poorly understood. This study investigates water-deprivation-induced gut dysbiosis and identifies Bacteroides acidifaciens (B.acidifaciens) as a critical mediator of epithelial barrier resilience. Using a murine model of graded water restriction, we observed colon shortening, villus atrophy, goblet cell loss, and barrier disruption correlated with water-deprivation severity. Oral supplementation of B.acidifaciens restored colonic architecture, enhanced mucin secretion, and ameliorated barrier dysfunction in water-deprived mice. Mechanistically, B.acidifaciens maintained barrier homeostasis by directly stimulating mucus production in intestinal epithelial cells and upregulating the expression of tight junction proteins. These findings establish B.acidifaciens as a critical species in mitigating water-deprivation-induced colon injury and advance our understanding of microbiota-directed interventions for dehydration-associated gastrointestinal disorders.

Unraveling the Gut-Liver-Brain Axis: Microbiome, Inflammation, and Emerging Therapeutic Approaches

The gut-liver-brain axis (GLB axis) plays a crucial role in maintaining metabolic, immune, and neurological homeostasis. The gut microbiota influences systemic health through its metabolites, including short-chain fatty acids (SCFAs), bile acids (BAs), and tryptophan (Trp) derivatives, which regulate immune function, lipid metabolism, and neurotransmitter balance. Dysbiosis is an imbalance in gut microbiota that has been implicated in metabolic dysfuntion associated fatty liver disease (MAFLD), alcohol-associated liver disease (AALD), and neuroinflammatory conditions such as schizophrenia. Increased gut permeability allows microbial byproducts like lipopolysaccharides (LPSs) to enter the liver and brain, activating inflammatory pathways that contribute to disease progression. Moreover, hepatic dysfunction can lead to neuroinflammation and cognitive impairments. Understanding the interplay between microbial metabolites and host physiology provides insight into novel therapeutic interventions. Strategies such as probiotics, prebiotics, synbiotics, fecal microbiota transfer (FMT), and postbiotics offer potential treatments to restore gut eubiosis and mitigate disease severity. This review highlights the mechanistic role of the GLB axis in health and disease, emphasizing microbiome-targeted therapies as a promising avenue for managing metabolic and neuropsychiatric disorders. Trial Registration: ClinicalTrials.gov identifier: NCT04823676, NCT02496390, NCT06024681, NCT02721264.

The axillary lymphoid organ is an external, experimentally accessible immune organ in the zebrafish

Lymph nodes and other secondary lymphoid organs play critical roles in immune surveillance and immune activation in mammals, but the deep internal locations of these organs make it challenging to image and study them in living animals. Here, we describe a previously uncharacterized external immune organ in the zebrafish ideally suited for studying immune cell dynamics in vivo, the axillary lymphoid organ (ALO). This small, translucent organ has an outer cortex teeming with immune cells, an inner medulla with a mesh-like network of fibroblastic reticular cells along which immune cells migrate, and a network of lymphatic vessels draining to a large adjacent lymph sac. Noninvasive high-resolution imaging of transgenically marked immune cells can be carried out in ALOs of living animals, which are readily accessible to external treatment. This newly discovered tissue provides a superb model for dynamic live imaging of immune cells and their interaction with pathogens and surrounding tissues, including blood and lymphatic vessels.

Tools for investigating host-microbe crosstalk using glycan analysis probes inspired by human lectins

Human lectins are critical carbohydrate-binding proteins that recognize diverse glycoconjugates from microorganisms and can play a key role in host-microbe interactions. Despite their importance in immune recognition and microbe binding, the specific glycan ligands and functions of many human lectins remain poorly understood. Using previous proof-of-concept studies on selected lectins as the foundation for this work, we present ten additional glycan analysis probes (GAPs) from a diverse set of human soluble lectins, offering robust tools to investigate glycan-mediated interactions. We describe a protein engineering platform that enables scalable production of GAPs that maintain native-like conformations and oligomerization states, equipped with functional reporter tags for targeted glycan profiling. We demonstrate that the soluble GAP reagents can be used in various applications, including glycan array analysis, mucin-binding assays, tissue staining, and microbe binding in complex populations. These capabilities make GAPs valuable for dissecting interactions relevant to understanding host responses to microbes. The tools can also be used to probe differential microbial and mammalian glycan interactions, which are crucial for understanding the interactions of lectins in a physiological environment where both glycan types exist. GAPs have potential as diagnostic and prognostic tools for detecting glycan alterations in chronic diseases, microbial dysbiosis, and immune-related conditions.

Ginsenoside Rh4 inhibits colorectal cancer via the modulation of gut microbiota-mediated bile acid metabolism

INTRODUCTION

Dysbiosis of the gut microbiota is emerging as a pivotal factor in the pathogenesis of colorectal cancer (CRC). Ginsenoside Rh4 (Rh4) is an active compound isolated from ginseng with beneficial effects in modulating intestinal inflammation and gut microbiota dysbiosis, but how Rh4 regulates the gut microbiota to alleviate CRC remains underexplored.

OBJECTIVES

We investigated the impact of Rh4 on CRC and the mechanism of its action in inhibiting CRC via modulation of gut microbiota.

METHODS

We used the AOM/DSS model and employed transcriptomics, genomics and metabolomics techniques to explore the inhibitory impact of Rh4 on CRC. Furthermore, we employed experiments involving antibiotic treatment and fecal microbiota transplantation (FMT) to investigate the role of the gut microbiota. Finally, we elucidated the pivotal role of key functional bacteria and metabolites regulated by Rh4 in CRC.

RESULTS

Our research findings indicated that Rh4 repaired intestinal barrier damage caused by CRC, alleviated intestinal inflammation, and inhibited the development of CRC. Additionally, Rh4 inhibited CRC in a gut microbiota-dependent manner. Rh4 increased the diversity of gut microbiota, enriched the probiotic Akkermansia muciniphila (A. muciniphila), and alleviated gut microbiota dysbiosis caused by CRC. Subsequently, Rh4 regulated A. muciniphila-mediated bile acid metabolism. A. muciniphila promoted the production of UDCA by enhancing the activity of 7α-hydroxysteroid dehydrogenase (7α-HSDH). UDCA further activated FXR, modulated the TLR4-NF-κB signaling pathway, thus inhibiting the development of CRC.

CONCLUSION

Our results confirm that Rh4 inhibits CRC in a gut microbiota-dependent manner by modulating gut microbiota-mediated bile acid metabolism and promoting the production of UDCA, which further activates the FXR receptor and regulates the TLR4-NF-κB signaling pathway. Our results confirm that Rh4 has the potential to be used as a modulator of gut microbiota for preventing and treatment of CRC.

Faecal mucoprotein MUC2 is decreased in multiple sclerosis and is associated with mucin degrading bacteria

BACKGROUND

The gut microbiome is altered in MS and may contribute to disease by disrupting the intestinal barrier. The colonic mucus barrier, which is primarily composed of mucin protein 2 (MUC2), plays a crucial role in providing a barrier between colonic epithelial cells and the microbiome. Disruption of intestinal epithelial and mucus barriers has been reported in inflammatory bowel disease (IBD) and Parkinson's disease (PD) but has not been studied in the context of the microbiome in multiple sclerosis (MS).

METHODS

We investigated the epithelial tight junction protein zonulin occludins 1 (ZO-1), mucus protein MUC2, inflammatory stool markers (calprotectin), and gut microbiota composition in a cohort of subjects with relapsing and progressive MS.

FINDINGS

MUC2 was decreased in stool of subjects with both relapsing and progressive MS. ZO-1 was elevated in the serum of subjects with progressive MS but was not altered in the stool. Inflammatory markers typically elevated in IBD and PD, including calprotectin, were not altered in MS stool, suggesting disease specificity of altered gut physiology in MS. Microbiota with known mucus degrading capacity were elevated in the stool of subjects with MS and negatively correlated with mucus protein levels.

INTERPRETATION

Taken together, these findings suggest reduced gut barrier function in MS which is linked to increased mucin degrading bacteria.

FUNDING

This work was supported by grants from the National MS Society, the NIH/NINDS, the Nancy Davis Race to Erase MS Young Investigator Award, the Water Cove Charitable Foundation, and the Clara E. and John H. Ware Jr.

FOUNDATION

Sheng Mai San Modulates the Heart-Gut-Microbiota Axis to Mitigate Heat Stress-Induced Damage in Rats

Heat stress has become a significant challenge in animal husbandry and human health, posing significant threats to both livestock and human health and profoundly impacting agricultural productivity. Sheng Mai San has been shown to effectively alleviate heat stress, yet the underlying mechanisms remain unclear. Therefore, this study established a heat stress model and employed Sheng Mai San as an intervention, with NAC as the positive control. Using histopathological analysis, Western blotting, ELISA, and 16S rDNA sequencing, we investigated the protective effects of Sheng Mai San against heat-stress-induced cardiac and intestinal injuries, as well as gut microbiota dysbiosis. The results demonstrated that heat stress-induced cardiac injury primarily occurred within 6-12 h of the cessation of heat stress. This injury was manifested by a significant elevation in the cardiac index, accompanied by attenuated expression of cardiac antioxidants (GSH, SOD, CAT, and T-AOC) and increased MDA content. Following Sheng Mai San intervention, the cardiac index was reduced, antioxidant indices (GSH, SOD, and CAT) were significantly elevated, and MDA and inflammatory markers (IL-1β, IL-6, and TNF-α) were markedly decreased. Additionally, Sheng Mai San was found to activate the Keap1-Nrf2 signaling pathway in the heart. Sheng Mai San demonstrated significant protective effects on small intestinal morphology, attenuating pathological alterations while promoting goblet cell proliferation. Analysis of the gut microbiota revealed that Sheng Mai San increased the Chao1, ACE, Shannon, and Simpson indices while reducing the abundance of harmful bacteria, such as g_Globicatella, g_Thermoactinomyces, g_Staphylococcus, g_Gemella, and g_Veillonella. Additionally, it promoted the expression of beneficial bacteria, including g_Lactobacillus and g_Ruminococcaceae. In summary, Sheng Mai San alleviates heat stress-induced cardiac hypertrophy and restores the oxidative stress balance in the heart. It also mitigates pathological damage in the small intestine, enhances the diversity and richness of the gut microbiota, and ameliorates gut microbiota dysbiosis. These findings highlight the significance of the heart-small intestine-gut microbiota axis in the protective effects of Sheng Mai San against heat stress injury. This study provides a potential therapeutic approach for heat-stress-related diseases and offers insights into the development of anti-heat-stress drugs.

Prophylactic administration of overproducing-abscisic acid Bacillus licheniformis attenuated DSS-induced colitis in mice by regulating the gut microbiota and immune activity

BACKGROUND

Inflammatory bowel disease (IBD) involves the complex interplay among the mucosal barrier, microbiota, immunity and genetic factors. There are currently no satisfactory treatments for IBD. Administration of the probiotic Bacillus licheniformis (Bl) can improves colitis by regulating the gut microbiota. The phytohormone abscisic acid (ABA) treatment has favorable effects on immunity, as well as on inflammatory diseases like colitis. We hypothesized that the expression of an additional cyp gene by the Bl to increase its ABA production would enhance its effects.

RESULTS

In this study, we found that a Bl-cyp strain overexpressing the cyp gene secreted more ABA into its supernatant than either the parental Bl stain or a Bl-pET82a strain expressing only a vector pET82a when these bacteria were grown in Nfb medium for 48 h. The prophylactic administration of the Bl-cyp strain culture more effectively attenuated dextran sodium sulfate (DSS)-induced colitis in mice compared to the Bl and Bl-pET28a strains. These findings were associated with significantly reduced epithelial barrier damage, as well as increased number of goblet cells and expression levels of occludin gene in the colonic epithelial layer, and decreased serum LPS levels in the Bl-cyp group. In addition, the administration of Bl-cyp strain effectively regulated the disordered gut microbiota by improving their diversity, richness and compositions more than the Bl or Bl-pET82a strain, including the ratio of Bacteroidota: Bacillota. It also inhibited the excessive growth of opportunistic pathogen Escherichia just like the Bl or Bl-pET82a strain. Moreover, the preventive administration of the Bl-cyp strain to mice following DSS-induced colitis enhanced the proportion of Treg cells and suppressed the proportion of Th17 cells in mesenteric lymph nodes (MLNs), decreased the levels of pro-inflammatory cytokines TNF-α, IL-6, and IL-22, and increased the level of anti-inflammatory IL-10 in colon tissues, similar to treatment with a high concentration of the ABA standard (ABA-H). Notably, the treatment with the Bl-cyp strain more effectively regulated the disordered microbiota than the ABA-H.

CONCLUSIONS

The administration of the Bl-cyp strain may provide a novel preventive approach for IBD, and may exert its effects by modulating the gut microbiota and host's immune status.

Modified Pulsatilla decoction ameliorates ulcerative colitis by affecting gut microbiota and metabolite profiles

To investigate the therapeutic effects of a specific modified Pulsatilla decoction (MPD) on ulcerative colitis (UC) in mice, 32 male Balb/c mice were randomly assigned to four groups: Control, Model, High-dose (H-dose), and Low-dose (L-dose), with eight mice per group. All groups except the Control group were administered 3% dextran sulfate sodium (DSS) in their drinking water for 7 days to induce acute UC. The H-dose group and L-dose group mice were gavaged, respectively, with different concentrations of MPD, while the Control group and Model group received the same amount of steriled water by gavage. Clinical symptoms of the mice were observed and recorded throughout the study. Subsequently, pathological sections of the colon tissues were prepared, and 16S rRNA high-throughput sequencing and metabolomics analysis were conducted on the intestinal contents. The results indicated that MPD improved the structure and morphology of colon tissue, significantly reducing inflammatory damage in DSS-treated mice. Furthermore, MPD alleviated DSS-induced intestinal injury by enhancing the abundance of beneficial intestinal probiotics, such as Actinobacteriota and Oscillospirates. Metabolomic analysis revealed significant changes in the MPD group compared to the Model group, with 53 metabolites upregulated and 22 downregulated. Key upregulated metabolites included Esculetin, Glutarate semialdehyde, and Licoricone, while downregulated metabolites included Ectoine and Trans-Piceid. KEGG enrichment analysis indicated that MPD primarily targets pathways such as linoleic acid metabolism, VEGF signaling, and glutamatergic synapse, highlighting its potential regulatory effects. In conclusion, we revealed that this MPD has the potential to alleviate DSS-induced colitis by reducing inflammation, regulating intestinal microbiota and intestinal metabolism.

Mucus and mucin: changes in the mucus barrier in disease states

In this review we discuss mucus, the viscoelastic secretion from goblet or mucous producing cells that covers and protects all non-keratinized wet epithelial surfaces. In addition to the surface of organs directly contacting with the external environment such as the eyes, this layer provides protection to the underlying gastrointestinal, respiratory and female reproductive tracts by trapping pathogens, irritants, environmental fine particles and potentially harmful foreign substances. Mucins, the primary structural components of mucus, form structurally different mucus layers at different sites in a process regulated by a variety of factors. Currently, more and more studies have shown that the mucus barrier is not only closely related to various intestinal mucus diseases, but also involved in the occurrence and development of various airway diseases and mucus-related diseases, thus it may become a new target for the treatment of various related diseases in the future. Since the dysfunction of the mucous layer is closely related to various pathological processes, in-depth understanding of its molecular mechanism and physiological role is of great theoretical and practical significance for disease prevention and treatment. Here, we discuss different aspects of the mucus layer by focusing on its chemical composition, synthetic pathways, and some of the characteristics of the mucus layer in physiological and pathological situations.

The Identification of a Glucuronyltransferase-Related Gene, GlcAT-S, with Putative Mucus Protection and Anti-Inflammatory Effects from Gut-Damaged Drosophila by Dextran Sulfate Sodium (DSS)

The intestinal epithelium, which is protected by mucosal surfaces composed of mucins and other glycoproteins, functions as a selective barrier that absorbs nutrients while preventing the translocation of harmful substances. To understand the mechanisms between mucosal disruption and tissue inflammation, we orally administrated a mucus-disrupting agent, dextran sodium sulfate, to Drosophila melanogaster and screened 63 differentially expressed genes (DEGs). Through a database search using bioinformatics tools (CHEA3 and WebGestalt), we identified ELK1 as a potential key transcription factor for the selected DEGs, and among the 63 DEGs, ELK1-related genes, B3GAT3, FIBP, and TENT2 (GlcAT-S, Fibp, and Wisp in Drosophila), were selected as the relevant genes that respond to mucus disruption. We confirmed that enterocyte (EC)-specific GlcAT-S knockdown by RNAi significantly reduced gut length and increased intestinal stem cell proliferation in Drosophila. Additionally, in EC-specific GlcAT-S-knockdown flies, it was observed that the mucus-production-related genes, Muc68D and Mur29B, were specifically reduced, whereas the inflammatory cytokines egr and upd3 were overexpressed. This study provides evidence that GlcAT-S is involved in the regulation of intestinal inflammation in Drosophila and plays a protective role against mucus disruption. Our findings suggest that GlcAT-S may be a potential therapeutic target for the treatment of intestinal inflammatory diseases such as IBD.

Development and characterization of a 2D porcine colonic organoid model for studying intestinal physiology and barrier function

The porcine colon epithelium plays a crucial role in nutrient absorption, ion transport, and barrier function. However ethical concerns necessitate the development of alternatives to animal models for its study. The objective of this study was to develop and characterize a two-dimensional (2D) in vitro model of porcine colonic organoids that closely mimics native colon tissue, thereby supporting in vitro research in gastrointestinal physiology, pathology, and pharmacology. Porcine colonic crypts were isolated and cultured in three-dimensional (3D) organoid systems, which were subsequently disaggregated to form 2D monolayers on transwell inserts. The integrity of the monolayers was evaluated through the measurement of transepithelial electrical resistance (TEER) and electron microscopy. The functional prerequisites of the model were evaluated through the measurement of the mRNA expression of key ion channels and transporters, using quantitative RT-PCR. Ussing chamber experiments were performed to verify physiological activity. The 2D monolayer displayed robust TEER values and retained structural characteristics, including microvilli and mucus-secreting goblet cells, comparable to those observed in native colon tissue. Gene expression analysis revealed no significant differences between the 2D organoid model and native tissue with regard to critical transporters. Ussing chamber experiments demonstrated physiological responses that were consistent with those observed in native colonic tissue. In conclusion, 2D porcine colonic organoid model can be recommended as an accurate representation of the physiological and functional attributes of the native colon epithelium. This model offers a valuable tool for investigating intestinal barrier properties, ion transport, and the pathophysiology of gastrointestinal diseases, while adhering to the 3R principles.

A type 4 resistant potato starch alters the cecal microbiome, gene expression and resistance to colitis in mice fed a Western diet based on NHANES data

Four major types of resistant starch (RS1-4) are present in foods and can be fermented to produce short-chain fatty acids (SCFAs), alter the microbiome and modulate post-prandial glucose metabolism. While studies in rodents have examined the effects of RS4 consumption on the microbiome, fewer have examined its effect on gene expression in the cecum or colon or resistance to bacterial-induced colitis, and those that have, use diets that do not reflect what is typically consumed by humans. Here we fed mice a Total Western Diet (TWD), based on National Health and Nutrition Examination Survey (NHANES) data for 6-7 weeks and then supplemented their diet with 0, 2, 5, or 10% of the RS4, Versafibe 1490™ (VF), a phosphorylated and cross-linked potato starch. After three weeks, mice were infected with Citrobacter rodentium (Cr) to induce colitis. Infected mice fed the 10% VF diet had the highest levels of Cr fecal excretion at days 4, 7 and 11 post-infection. Infected mice fed the 5% and 10%VF diets had increased hyperplasia and colonic damage compared with the control. Changes in bacterial genera relative abundance, and alpha and beta diversity due to diet were most evident in mice fed 10% VF. Cr infection also resulted in specific changes to the microbiome and gene expression both in the cecum and the colon compared with diet alone, including the expression of multiple antimicrobial genes, Reg3b, Reg3g, NOS2 and Ifng. These results demonstrate that VF, a RS4, alters cecal and colonic gene expression, the microbiome composition and resistance to bacterial-induced colitis.

Systemic IGF-1 administration prevents traumatic brain injury induced gut permeability, dysmorphia, dysbiosis, and the increased number of immature dentate granule cells

Traumatic brain injury (TBI) occurs in 2-3 million Americans each year and is a leading cause of death and disability. Among the many physiological consequences of TBI, the hypothalamic pituitary axis (HPA) is particularly vulnerable, including a reduction in growth hormone (GH) and insulin-like growth factor (IGF-1). Clinical and preclinical supplementation of IGF-1 after TBI has exhibited beneficial effects. IGF-1 receptors are prominently observed in many tissues, including in the brain and in the gastrointestinal (GI) system. In addition to causing damage in the brain, TBI also induces GI system damage, including inflammation and alterations to intestinal permeability and the gut microbiome. The goal of this study was to assess the effects of systemic IGF-1 treatment in a rat model of TBI on GI outcomes. Because GI dysfunction has been linked to hippocampal dysfunction, we also examined proliferation and immature granule cells in the hippocampal dentate gyrus. 10-week-old male rats were treated with an intraperitoneal (i.p.) dose of IGF-1 at 4 and 24 h after lateral fluid percussion injury (FPI). At 3- and 35-days post-injury (DPI), gut permeability, gut dysmorphia, the fecal microbiome, and the hippocampus were assessed. FPI-induced permeability of the blood-gut-barrier, as measured by elevated gut metabolites in the blood, and this was prevented by the IGF-1 treatment. Gut dysmorphia and alterations to the microbiome were also observed after FPI and these effects were ameliorated by IGF-1, as was the increase in immature granule cells in the hippocampus. These findings suggest that IGF-1 can target gut dysfunction and damage after TBI, in addition to its role in influencing adult hippocampal neurogenesis.

Prebiotics and Probiotics Supplementation in Pigs as a Model for Human Gut Health and Disease

Animal models are an essential part of translational research for the purpose of improving human health. The pig is a potential human research model that can be used to assess the effects of dietary interventions, pathologies, and drugs on gut health and the microbiome, due to its anatomical and physiological similarity to humans. It is recognised that a healthy gut is closely linked to the prevention of several chronic diseases, including obesity, diabetes, gastrointestinal inflammation, as well as neurological and cardiovascular diseases. The use of prebiotics and probiotics plays an important role in maintaining a healthy digestive system, which is responsible for modulating all other body functions. The present review focuses on the applications of prebiotics and probiotics in the pig as an animal model in healthy and diseased conditions, in order to highlight the efficacy of these molecules in the perspective of human health outcomes. The data support the use of prebiotics to improve intestinal health in both healthy and diseased states. In addition, the use of human microbiota-associated (HMA) gnotobiotic pigs provided a good model to study the intestinal and systemic immune response and microbiota composition following probiotic supplementation after a vaccine or virus challenge.

Phytochemicals act holistically to enhance host defenses during poultry coccidiosis

This study was conducted to investigate the effects of a phytochemical mixture containing full spectrum cinnamon, clove, and oregano essential oils (CCO) on the growth performance, intestinal immunity, and intestinal integrity of broilers infected with coccidiosis. In chicken macrophage cells (CMCs), inflammation was induced with 1.0 µg/mL LPS, followed by stimulating with CCO at three concentrations (1.0, 10.0, and 100 µg/mL) and measuring the gene expression levels of IL-1β and IL-8. In chicken intestinal epithelial cells (IECs), CCO was added and cultured, and the gene expression levels of occludin, ZO-1, and MUC2 were measured. In the in vivo experiment, one hundred and twenty male broiler chickens (0-day-old) were allocated into three treatment groups: (1) basal diet without infection (NC), (2) basal diet with E. maxima infection (PC), and (3) CCO at 4.5 mg/kg feed with E. maxima infection (CCO). Body weight (BW) was measured on days 0, 7, 14, 20, and 22. PC and CCO groups were orally infected with E. maxima on day 14. Jejunal samples were collected on day 22 to conduct gene expression analysis of cytokines, TJ proteins, and antioxidant enzymes. CCO significantly decreased IL-1β and IL-8 in CMCs and increased ZO-1 and MUC2 in IECs in a dose-dependent manner. In the E. maxima-infected groups, dietary CCO tended to mitigate BW loss due to infection. Upon infection, proinflammatory cytokines were suppressed in the CCO group compared to the PC group. Dietary CCO also increased the expression of occludin and JAM-2 in the jejunum. However, CCO did not reduce the oocyst number in coccidiosis-infected chickens. These results suggest that dietary CCO supplementation may improve intestinal immunity and permeability, helping to reduce productivity losses in E. maxima-infected broilers through gut physiological responses, rather than direct antimicrobial effects. These results show the advantage of using in vitro screening based on host-mediated responses, and not on direct pathogen killing, when exploring new phytochemicals to mitigate disease response to reduce economic losses due to coccidiosis.

Crosstalk with infant-derived Th17 cells, as well as exposure to IL-22 promotes maturation of intestinal epithelial cells in an enteroid model

Introduction

The intestinal epithelium of human infants is developmentally immature compared to that of adults. Exactly how this immaturity affects key epithelial functions and their interactions with nearby immune cells remains an understudied area of research, partly due to limited access to non-diseased infant gut tissues. Human intestinal organoids, or "mini guts" generated from tissue stem cells, are promising models for investigating intestinal biology and disease mechanisms. These three-dimensional structures closely mimic their tissue of origin, including cellular physiology and genetics. We have also previously shown that neonatal Th17 cells represent a distinct cell population with a cytokine profile skewed toward IL-22 production rather than IL-17A, as seen in adult Th17 cells.

Methods

In this study, we sought to model the impact of neonatal-derived Th17 cytokine, namely IL-22 and the intestinal epithelium using infant-derived ileal enteroids. We generated enteroids from ileal biopsies from infants (< 6 months old) and cultured them for seven days with standard organoid growth media, organoid media supplemented with conditioned media from cord-blood-derived Th17 cells, or media supplemented with recombinant IL-22. We assessed morphological changes and conducted transcriptomics profiling via RNAseq.

Results

Exposing enteroids to neonatal Th17-cells-derived conditioned media led to enhanced growth, maturation, and differentiation as compared to control media. These effects were ablated when an IL-22 neutralizing antibody was used, while conversely, supplementing with recombinant IL-22 mimicked the Th17 effects, increasing intestinal epithelial cell proliferation and inducing marked differentiation of secretory cells. Our transcriptomic profiling similarly demonstrated significant changes in response to IL-22 with downregulation of Wnt and Notch signaling and upregulation of immune pathways, particularly interferon signaling. The transcriptomic data also suggested that IL-22 treatment led to changes in cell type composition with an increase in stem- and progenitor cells at the expense of enterocytes.

Conclusion

Taken together, our data suggests that early-life intestinal development is likely influenced by IL-22-dependent crosstalk between the infant epithelium and exposure to neighboring Th17 cells. This promotes epithelial cell maturation and immune readiness, reflected at both the morphological and molecular levels. Our work also provides a relevant framework for studying healthy infant gut development, which can be further leveraged to examine early-life gastrointestinal disorders, model complex human disease, and therapeutic testing while reducing reliance on animal models.

Lentinan mitigates ulcerative colitis via the IL-22 pathway to repair the compromised mucosal barrier and enhance antimicrobial defense

Ulcerative colitis (UC) involves chronic, complex pathology of the intestinal mucosa. Current treatments are limited in efficacy and associated with adverse effects, highlighting the urgent need for improved therapeutic options. Lentinan (LNT), a polysaccharide drug commonly used in clinical immune modulation therapies, shows potential for UC treatment, though its specific targets and mechanisms remain unclear. In this study, LNT administration effectively mitigated DSS-induced colitis in mice, enhanced mucosal barrier function and antimicrobial defense. Specifically, LNT modulated the balance between tissue-resident and infiltrating macrophages, thereby improving pathogen clearance and enhancing the immunological barrier. Notably, we identified a novel effect of LNT in regulating the macrophage Dectin-1-ILC3 axis to increase IL-22 secretion. This led to the modulation of epithelial O-glycan fucosylation, antimicrobial peptides, and epithelial stem cells, thereby strengthening antimicrobial defenses and the physicochemical barrier. Neutralization with anti-IL-22 antibodies diminished the therapeutic effect of LNT in UC, underscoring the critical role of IL-22 in LNT-mediated treatment. Overall, this study highlights the potential of LNT as a novel therapeutic agent for UC, offering new insights into its molecular mechanisms and clinical application.

Butyrate Derivatives Exhibited Anti-Inflammatory Effects and Enhanced Intestinal Barrier Integrity in Porcine Cell Culture Models

Butyrate and its derivatives may influence inflammatory status and physiology in a variety of organisms and organ systems. Inflammatory conditions of the gastrointestinal tract, such as post-weaning diarrhea, negatively impact swine. Dietary intervention with butyrate-based compounds should be considered a strategy to improve disease resistance in pigs. We aimed to assess the properties of different forms of butyrate treatments using porcine cell culture experiments. This assessment may inform future in vivo feed experiments designed to determine its potential application of the dietary supplements for pigs. An intestinal porcine enterocyte cell line, IPEC-J2, was seeded at 5 × 103 cells/mL in 96-well plates to confirm cell viability by MTT assay for each dose range used in the current experiments (0, 0.5, 1, 2, 4 mM butyric acid or tributyrin; 0, 1, 2, 4, 8 mM sodium butyrate or monobutyrin). For transepithelial electrical resistance (TEER) analysis, IPEC-J2 was seeded at 5 × 105 cells/mL in 12-well transwell inserts and treated with 5 levels of each butyrate derivative after adherence (n = 5). TEER was measured at 24, 48, and 72 h post-treatment to quantify intestinal barrier integrity of IPEC-J2 monolayers. Butyric acid, sodium butyrate, and monobutyrin significantly increased (p < 0.05) TEER in IPEC-J2 at different time points compared with control. Further, porcine alveolar macrophages (PAMs) were harvested from donor weaned piglets (n = 6) via bronchoalveolar lavage and isolated for primary culture (6 × 105 cells/well, 6-well plates). PAMs were treated with five levels of each butyrate derivative with or without lipopolysaccharide (LPS, 1 μg/mL) challenge. The concentrations of TNF-α and IL-1β in cell culture supernatants were measured by enzyme-linked immunosorbent assay (ELISA). Butyric acid and sodium butyrate treatments reduced the production of TNF-α in LPS-challenged PAMs (linear; p < 0.05). Different butyrate derivatives exerted anti-inflammatory properties and improved intestinal barrier integrity.

The Duodenal Microenvironment in Functional Dyspepsia

Functional dyspepsia (FD) is a chronic gastrointestinal disorder without a readily identifiable organic cause, resulting in bothersome upper abdominal symptoms. It is a highly prevalent disorder of which the pathophysiology remains mostly elusive, despite intensive research efforts. However, recent studies have found alterations in the microenvironment of the duodenum in patients with FD. In this review we summarize the duodenal microenvironment in homeostatic conditions and the alterations found in patients with FD, highlighting the similarities and discrepancies between different studies. The most consistent findings, being an impaired duodenal barrier and duodenal immune activation, are reviewed. We discuss the potential triggers for these observed alterations, including psychological comorbidities, luminal alterations and food related triggers. In summary, this review presents the evidence of molecular and cellular changes in patients with FD, with an impaired duodenal barrier and activated mucosal eosinophils and mast cells, challenging the notion that FD is purely functional, and offering different targets for potential future treatments.

Abortive PDCoV infection triggers Wnt/β-catenin pathway activation, enhancing intestinal stem cell self-renewal and promoting chicken resistance

Porcine deltacoronavirus (PDCoV) is an emerging coronavirus causing economic losses to swine industries worldwide. PDCoV can infect chickens under laboratory conditions, usually with no symptoms or mild symptoms, and may cause outbreaks in backyard poultry and wildfowl, posing a potential risk of significant economic loss to the commercial poultry industry. However, the reasons for such a subdued reaction after infection are not known. Here, using chicken intestinal organoid monolayers, we found that although PDCoV infects them nearly as well as porcine intestinal organoid monolayers, infection did not result in detectable amounts of progeny virus. In ex vivo and in vivo experiments using chickens, PDCoV infection failed to initiate interferon and inflammatory responses. Additionally, infection did not result in a disrupted intestinal barrier nor a reduced number of goblet cells and mucus secretion, as in pigs. In fact, the number of goblet cells increased as did the secreted mucus, thereby providing an enhanced protective barrier. Ex vivo PDCoV infection in chicken triggered activation of the Wnt/β-catenin pathway with the upregulation of Wnt/β-catenin pathway genes (Wnt3a, Lrp5, β-catenin, and TCF4) and Wnt target genes (Lgr5, cyclin D1, and C-myc). This activation stimulates the self-renewal of intestinal stem cells (ISCs), accelerating ISC-mediated epithelial regeneration by significant up-regulation of PCNA (transiently amplifying cells), BMI1 (ISCs), and Lyz (Paneth cells). Our data demonstrate that abortive infection of PDCoV in chicken cells activates the Wnt/β-catenin pathway, which facilitates the self-renewal and proliferation of ISCs, contributing to chickens' resistance to PDCoV infection.IMPORTANCEThe intestinal epithelium is the main target of PDCoV infection and serves as a physical barrier against pathogens. Additionally, ISCs are charged with tissue repair after injury, and promoting rapid self-renewal of intestinal epithelium will help to re-establish the physical barrier and maintain intestinal health. We found that PDCoV infection in chicken intestinal organoid monolayers resulted in abortive infection and failed to produce infectious virions, disrupt the intestinal barrier, reduce the number of goblet cells and mucus secretion, and induce innate immunity, but rather increased goblet cell numbers and mucus secretion. Abortive PDCoV infection activated the Wnt/β-catenin pathway, enhancing ISC renewal and accelerating the renewal and replenishment of shed PDCoV-infected intestinal epithelial cells, thereby enhancing chicken resistance to PDCoV infection. This study provides novel insights into the mechanisms underlying the mild or asymptomatic response to PDCoV infection in chickens, which is critical for understanding the virus's potential risks to the poultry industry.

Effects and Mechanisms of Pleurotus eryngii Polysaccharide on Intestinal Barrier Damage: Based on the Perspective of Its Interaction with Intestinal Mucus during Gut Digestion

In this study, pathways and mechanisms of action of a new type of Pleurotus eryngii polysaccharide (PEP) with known structural characteristics and probiotic properties in the intestine were investigated. An in vitro cell model was used to investigate the protective effects of complexes formed between PEPs and their related products with mucin against gut barrier damage. Dextran sulfate sodium salt-induced colitis was used to determine the characteristics of the interaction between PEPs and intestinal mucus (IMs) at different consumption times. Finally, the protective effect of PEPs against intestinal barrier damage was investigated, as mediated by IMs. The result showed that complexes of PEP-related products and mucin improved damage to the intestinal barrier. PEPs exhibited differential functional activities at different stages. In normal and colitis mice, the interactions between IMs and PEPs showed different characteristics. From the transport and absorption standpoint, the role of PEPs in driving intestinal health was also clarified in this study.

Leveraging Organ-on-Chip Models to Investigate Host-Microbiota Dynamics and Targeted Therapies for Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an idiopathic gastrointestinal disease with drastically increasing incidence rates. Due to its multifactorial etiology, a precise investigation of the pathogenesis is extremely difficult. Although reductionist cell culture models and more complex disease models in animals have clarified the understanding of individual disease mechanisms and contributing factors of IBD in the past, it remains challenging to bridge research and clinical practice. Conventional 2D cell culture models cannot replicate complex host-microbiota interactions and stable long-term microbial culture. Further, extrapolating data from animal models to patients remains challenging due to genetic and environmental diversity leading to differences in immune responses. Human intestine organ-on-chip (OoC) models have emerged as an alternative in vitro model approach to investigate IBD. OoC models not only recapitulate the human intestinal microenvironment more accurately than 2D cultures yet may also be advantageous for the identification of important disease-driving factors and pharmacological interventions targets due to the possibility of emulating different complexities. The predispositions and biological hallmarks of IBD focusing on host-microbiota interactions at the intestinal mucosal barrier are elucidated here. Additionally, the potential of OoCs to explore microbiota-related therapies and personalized medicine for IBD treatment is discussed.

Gut microbiota: The pivotal conduit in the onset of constipation and its alleviation by tea flower polysaccharides (TFP) in a mouse model

Plant-derived bioactive components, such as polysaccharides, provide promising alleviating effects on constipation with minimal side-effects compared to pharmacological interventions. This study aimed to explore the therapeutic potential of tea flower polysaccharides (TFP) on constipation and the involved mechanisms. In a loperamide-induced constipation mouse model, TFP administration significantly increased fecal water content from 54.23-57.30 % to 63.70-79.36 %, enhanced intestinal transit rate from 30.80 % to 38.81 %, and reduced gastrointestinal (GI) transit time from 234.4 min to 186.2 min. TFP restored levels of both excitatory and inhibitory hormones related to GI motility. Transcriptomic analysis of colonic epithelial cells revealed that TFP restored expression of 544 genes involved in various pathways, including the NF-κB and JAK-STAT signaling pathways, which are associated with the improvement of constipation. Gut microbiota analysis demonstrated that TFP mitigated dysbiosis by normalizing the Firmicutes/Bacteroidota ratio, inhibiting pathogenic genera (e.g., Helicobacter), and promoting beneficial genera (e.g., Muribaculaceae, Bacteroides, Parabacteroides). The mediating role of gut microbiota in the onset of constipation and its alleviation was confirmed through fecal microbiota transplantation (FMT). Furthermore, TFP and its combination with anti-constipation drugs alleviated constipation-induced hepatorenal damage. This study highlights TFP's potential in treating constipation and underscores the essential role of gut microbiota in its therapeutic effects.

The Role of Triterpenoids in Gastric Ulcer: Mechanisms and Therapeutic Potentials

Gastric ulcer (GU) is a prevalent gastrointestinal disorder impacting millions worldwide, with complex pathogenic mechanisms that may progress to severe illnesses. Conventional therapies relying on anti-secretory agents and antibiotics are constrained by drug abuse and increased bacterial resistance, highlighting the urgent need for safer therapeutic alternatives. Natural medicinal compounds, particularly triterpenoids derived from plants and herbs, have gained significant attention in recent years due to their favorable efficacy and reduced toxicity profiles. Emerging evidence indicates that triterpenoids exhibit potent anti-ulcer properties across various experimental models, modulating key pathways involved in inflammation, oxidative stress, apoptosis, and mucosal protection. Integrating current knowledge of these bioactive compounds facilitates the development of natural triterpenoids, addresses challenges in their clinical translation, deepens mechanistic understanding of GU pathogenesis, and drives innovation of therapeutic strategies for GU. This review comprehensively evaluates the progress of research on triterpenoids in GU treatment since 2000, discussing their biological sources, structural characteristics, pharmacological activities, and mechanisms of action, the animal models employed in the studies, current limitations, and the challenges associated with their clinical application.

Gut microbiota in the development and progression of chronic liver diseases: Gut microbiota-liver axis

The gut microbiota (GM) is a highly dynamic ecology whose density and composition can be influenced by a wide range of internal and external factors. Thus, "How do GM, which can have commensal, pathological, and mutualistic relationships with us, affect human health?" has become the most popular research issue in recent years. Numerous studies have demonstrated that the trillions of microorganisms that inhabit the human body can alter host physiology in a variety of systems, such as metabolism, immunology, cardiovascular health, and neurons. The GM may have a role in the development of a number of clinical disorders by producing bioactive peptides, including neurotransmitters, short-chain fatty acids, branched-chain amino acids, intestinal hormones, and secondary bile acid conversion. These bioactive peptides enter the portal circulatory system through the gut-liver axis and play a role in the development of chronic liver diseases, cirrhosis, and hepatic encephalopathy. This procedure is still unclear and quite complex. In this study, we aim to discuss the contribution of GM to the development of liver diseases, its effects on the progression of existing chronic liver disease, and to address the basic mechanisms of the intestinal microbiota-liver axis in the light of recent publications that may inspire the future.

N-glycosylation enzyme Mpi is essential for mucin O-glycosylation, host-microbe homeostasis, Paneth cell defense, and metabolism

Intestinal homeostasis relies on a protective mucus layer that separates bacteria from the host, with Muc2 as its primary component. This secreted, gel-forming mucin is heavily O-glycosylated, allowing it to retain water and support beneficial bacteria. For the first time, we demonstrate that Muc2 N-glycosylation plays a critical in mucin maturation, O-glycosylation, barrier integrity, and the prevention of dysbiosis. Using mouse models with global and intestine-specific N-glycan deficiency- caused by the loss of the mannose producing enzyme, Mpi- we uncover an unexpected link between N-glycosylation and intestinal homeostasis. Our findings reveal that Mpi hypomorphic mice are highly sensitive to DSS-induced colitis, while Mpi flox; Villin Cre mice spontaneously develop disease, exhibiting increased ER stress and dysbiosis. Additionally, electron microscopy, proteomics, and gene expression analyses of goblet and Paneth cells indicate immaturity, mitochondrial loss, and disruptions in lipid metabolism. These results highlight the fundamental role of N-glycosylation in maintaining intestinal homeostasis.

Unraveling the Biological Properties of Whey Peptides and Their Role as Emerging Therapeutics in Immune Tolerance

Whey is a natural by-product of the cheese-making process and represents a valuable source of nutrients, including vitamins, all essential amino acids and proteins with high quality and digestibility characteristics. Thanks to its different techno-functional characteristics, such as solubility, emulsification, gelling and foaming, it has been widely exploited in food manufacturing. Also, advances in processing technologies have enabled the industrial production of a variety of whey-based products exerting biological activities. The beneficial properties of whey proteins (WPs) include their documented effects on cardiovascular, digestive, endocrine, immune and nervous systems, and their putative role in the prevention and treatment of non-communicable diseases (NCDs). In this regard, research on their application for health enhancement, based on the optimization of product formulation and the development of pharmaceuticals, is highly relevant. Beyond the health and nutritionally relevant effects as in in vivo animal studies, the allergenicity of WPs and WP hydrolysates is also herein tackled and discussed, as well as their potential role as therapeutics for immune tolerance and so-called tolerogenic effects. Grounded on the WPs' health-promoting functions, this paper presents the latest research showing the potential of whey-derived peptides as an alternative strategy in NCD treatment. This work also reports a careful analysis of their current use, also revealing which obstacles limit their full exploitation, thus highlighting the future challenges in the field. Concluding, safety considerations, encompassing WP allergenicity, are also discussed, providing some insights on the role of WPs and peptides in milk allergen immunotolerance.

The coadministration of Lactobacillus probiotic augments the antitumor effect of telmisartan in rats

Colorectal cancer (CRC) is a prevalent disease with a high mortality rate and is significantly affected by microbial dysbiosis. Recent research suggests that modulation of the gut microbiome can have therapeutic benefits and that Angiotensin-II Type 1 Receptor (AT1R) can stimulate cell growth, angiogenesis, and resistance to apoptosis in various cancers. In this study, the adjunctive administration of Lactobacillus spp. and telmisartan, an AT1R blocker, was explored in the treatment of CRC. The effect of telmisartan and a mixture of probiotic species, Lactobacillus delbrueckii and Lactobacillus fermentum, was assessed on key biomarkers and selected gut microbiota taxa in 1,2-dimethylhydrazine-induced CRC in rats. Angiogenesis, inflammation, and apoptosis were assessed by measuring vascular endothelial growth factor (VEGF), carcinoembryonic antigen (CEA), Interleukin 6 (IL-6), and Annexin V levels, respectively. The relative abundance of selected gut microbial taxa, including Bacteroides spp., Clostridium spp., Clostridium coccoides, Ruminococcus spp., and Lactobacillus spp. was analyzed to determine the change in the microbial composition in the different experimental groups of the animal model. This study demonstrated that the unique combination therapy using a Lactobacillus mixture and telmisartan effectively reduced VEGF and IL-6 levels, indicating decreased angiogenesis and inflammation. Lactobacillus spp. co-administration with telmisartan boosted programmed cell death, reversed dysbiosis, improved histopathological outcomes, and reduced CEA levels. These findings offer a new perspective on the role of Lactobacillus spp. and telmisartan in CRC treatment. Further research on their adjunctive use and therapeutic potential are needed to enhance clinical efficacy.

The coadministration of Lactobacillus probiotic augments the antitumor effect of telmisartan in rats

Colorectal cancer (CRC) is a prevalent disease with a high mortality rate and is significantly affected by microbial dysbiosis. Recent research suggests that modulation of the gut microbiome can have therapeutic benefits and that Angiotensin-II Type 1 Receptor (AT1R) can stimulate cell growth, angiogenesis, and resistance to apoptosis in various cancers. In this study, the adjunctive administration of Lactobacillus spp. and telmisartan, an AT1R blocker, was explored in the treatment of CRC. The effect of telmisartan and a mixture of probiotic species, Lactobacillus delbrueckii and Lactobacillus fermentum, was assessed on key biomarkers and selected gut microbiota taxa in 1,2-dimethylhydrazine-induced CRC in rats. Angiogenesis, inflammation, and apoptosis were assessed by measuring vascular endothelial growth factor (VEGF), carcinoembryonic antigen (CEA), Interleukin 6 (IL-6), and Annexin V levels, respectively. The relative abundance of selected gut microbial taxa, including Bacteroides spp., Clostridium spp., Clostridium coccoides, Ruminococcus spp., and Lactobacillus spp. was analyzed to determine the change in the microbial composition in the different experimental groups of the animal model. This study demonstrated that the unique combination therapy using a Lactobacillus mixture and telmisartan effectively reduced VEGF and IL-6 levels, indicating decreased angiogenesis and inflammation. Lactobacillus spp. co-administration with telmisartan boosted programmed cell death, reversed dysbiosis, improved histopathological outcomes, and reduced CEA levels. These findings offer a new perspective on the role of Lactobacillus spp. and telmisartan in CRC treatment. Further research on their adjunctive use and therapeutic potential are needed to enhance clinical efficacy.

Advances in intestinal epithelium and gut microbiota interaction

The intestinal epithelium represents a critical interface between the host and external environment, serving as the second largest surface area in the human body after the lungs. This dynamic barrier is sustained by specialized epithelial cell types and their complex interactions with the gut microbiota. This review comprehensively examines the recent advances in understanding the bidirectional communication between intestinal epithelial cells and the microbiome. We briefly highlight the role of various intestinal epithelial cell types, such as Paneth cells, goblet cells, and enteroendocrine cells, in maintaining intestinal homeostasis and barrier function. Gut microbiota-derived metabolites, particularly short-chain fatty acids and bile acids, influence epithelial cell function and intestinal barrier integrity. Additionally, we highlight emerging evidence of the sophisticated cooperation between different epithelial cell types, with special emphasis on the interaction between tuft cells and Paneth cells in maintaining microbial balance. Understanding these complex interactions has important implications for developing targeted therapeutic strategies for various gastrointestinal disorders, including inflammatory bowel disease, metabolic disorders, and colorectal cancer.

When short-chain fatty acids meet type 2 diabetes mellitus: Revealing mechanisms, envisioning therapies

Evidence is accumulating that short-chain fatty acids (SCFAs) produced by the gut microbiota play pivotal roles in host metabolism. They contribute to the metabolic regulation and energy homeostasis of the host not only by preserving intestinal health and serving as energy substrates but also by entering the systemic circulation as signaling molecules, affecting the gut-brain axis and neuroendocrine-immune network. This review critically summarizes the current knowledge regarding the effects of SCFAs in the fine-tuning of the pathogenesis of type 2 diabetes mellitus (T2DM) and insulin resistance, with an emphasis on the complex relationships among diet, microbiota-derived metabolites, T2DM inflammation, glucose metabolism, and the underlying mechanisms involved. We hold an optimistic view that elucidating how diet can influence gut bacterial composition and activity, SCFA production, and metabolic functions in the host will advance our understanding of the mutual interactions of the intestinal microbiota with other metabolically active organs, and may pave the way for harnessing these pathways to develop novel personalized therapeutics for glucometabolic disorders.

Biophysical modeling of membrane curvature generation and curvature sensing by the glycocalyx

Generation of membrane curvature is fundamental to cellular function. Recent studies have established that the glycocalyx, a sugar-rich polymer layer at the cell surface, can generate membrane curvature. While there have been some theoretical efforts to understand the interplay between the glycocalyx and membrane bending, there remain open questions about how the properties of the glycocalyx affect membrane bending. For example, the relationship between membrane curvature and the density of glycosylated proteins on its surface remains unclear. In this work, we use polymer brush theory to develop a detailed biophysical model of the energetic interactions of the glycocalyx with the membrane. Using this model, we identify the conditions under which the glycocalyx can both generate and sense curvature. Our model predicts that the extent of membrane curvature generated depends on the grafting density of the glycocalyx and the backbone length of the polymers constituting the glycocalyx. Furthermore, when coupled with the intrinsic membrane properties such as spontaneous curvature and a line tension along the membrane, the curvature generation properties of the glycocalyx are enhanced. These predictions were tested experimentally by examining the propensity of glycosylated transmembrane proteins to drive the assembly of highly curved filopodial protrusions at the plasma membrane of adherent mammalian cells. Our model also predicts that the glycocalyx has curvature-sensing capabilities, in agreement with the results of our experiments. Thus, our study develops a quantitative framework for mapping the properties of the glycocalyx to the curvature generation capability of the membrane.

Escherichia coli phage ΦPNJ-9 adheres to mucus via a variant Hoc protein

Phages, as antagonists of bacteria, hold significant promise for combating drug-resistant bacterial infections. Their host specificity allows phages to target pathogenic bacteria without disrupting the gut microbiota, offering distinct advantages in the prevention and control of intestinal pathogens. The interaction between the phage and the gut plays a crucial role in the efficacy of phage-mediated bacterial killing. However, the mechanisms underlying these interactions remain poorly understood. In this study, we demonstrate that the clinically isolated T4-like phage, ΦPNJ-9, effectively adheres to the intestinal mucosa in vivo. This adhesion is mediated by the phage's Hoc protein, which interacts with MUC2 in the mucus. The Hoc protein of ΦPNJ-9 represents a variant, consisting of only three domains and lacking Domain 3, in contrast to phage T4. The key interacting sites on ΦPNJ-9 Hoc are amino acids S183, L184, and T185 within Domain 2. Displaying Domain 2 of ΦPNJ-9 Hoc on the surface of M13 phage significantly enhances its adhesion to the intestinal mucosa. Additionally, we identify fucose residues in MUC2 as the critical binding sites for the phage. Through this adhesion, the phage occupies the intestinal niche, thereby protecting the mucosal layer from pathogenic Escherichia coli infections. Our findings highlight the role of Hoc proteins in phage adhesion to intestinal mucus and the variation in binding sites, providing key insights for phage-based strategies aimed at preventing and controlling intestinal pathogens.IMPORTANCEThe rise in antibiotic-resistant pathogenic bacteria has sparked renewed interest in phage therapy as a promising alternative, particularly for targeting intestinal pathogens due to phage's host specificity. However, clinical applications have revealed that many phages are ineffective in eliminating bacteria within the gut, primarily due to the complex interactions between the phage and the gut environment. However, the mechanisms underlying these interactions remain poorly understood. Our previous study demonstrated that a T4-like phage adheres to the intestinal mucosa through the interaction between its Hoc protein and MUC2 in the mucus. Whether this model is widespread among T4-like phages remains unknown. Here, we characterize a variant Hoc protein from a T4-like phage, and identify new binding sites within this protein. Our findings suggest that the interaction between Hoc and MUC2 is likely common, but the critical binding sites vary depending on the specific phage.

Unveiling roles of beneficial gut bacteria and optimal diets for health

The gut microbiome plays a pivotal role in human health, influencing digestion, immunity, and disease prevention. Beneficial gut bacteria such as Akkermansia muciniphila, Adlercreutzia equolifaciens, and Christensenella minuta contribute to metabolic regulation and immune support through bioactive metabolites like short-chain fatty acids (SCFAs). Dietary patterns rich in prebiotics, fermented foods, and plant-based bioactive compounds, including polyphenols and flavonoids, promote microbiome diversity and stability. However, challenges such as individual variability, bioavailability, dietary adherence, and the dynamic nature of the gut microbiota remain significant. This review synthesizes current insights into gut bacteria's role in health, emphasizing the mechanisms by which dietary interventions modulate microbiota. Additionally, it highlights advancements in microbiome-targeted therapies and the transformative potential of personalized nutrition, leveraging microbiota profiling and artificial intelligence (AI) to develop tailored dietary strategies for optimizing gut health and mitigating chronic inflammatory disorders. Addressing these challenges requires a multidisciplinary approach that integrates scientific innovation, ethical frameworks, and practical implementation strategies.

The essential role of prebiotics in restoring gut health in long COVID

The gut microbiota (GM) plays an essential role in human health, influencing not only digestive processes but also the immune system´s functionality. The COVID-19 pandemic has highlighted the complex interaction between viral infections and the GM. Emerging evidence has demonstrated that SARS-CoV-2 can disrupt microbial homeostasis, leading to dysbiosis and compromised immune responses. The severity of COVID-19 has been associated with a reduction in the abundance of several beneficial bacteria in the gut. It has been proposed that consuming probiotics may help to re-colonize the GM. Although probiotics are important, prebiotics are essential for their metabolism, growth, and re-colonization capabilities. This chapter delves into the critical role of prebiotics in restoring GM after COVID-19 disease. The mechanisms by which prebiotics enhance the metabolism of beneficial bacteria will be described, and how prebiotics mediate the re-colonization of the gut with beneficial bacteria, thereby restoring microbial diversity and promoting the resilience of the gut-associated immune system. The benefits of consuming prebiotics from natural sources are superior to those from chemically purified commercial products.

Efficacy of hyperimmunized egg yolk antibodies (IgY) against Campylobacter jejuni: In Vitro and In Vivo evaluations

Campylobacter infections are a prevalent cause of diarrheal disease in humans and are the most significant zoonotic pathogens worldwide. Human campylobacteriosis is generally via ingestion of contaminated poultry products. However, based on recent studies chicken egg yolk antibody (IgY) powder has great potential to reduce the cecum load of Campylobacter jejuni (C. jejuni) in broilers. To understand the effective and economically feasible dosage, two immunization and challenge studies were conducted using 30 layer hens and 250 broiler chickens and found a scientific approach, starting with in vitro evaluations and progressing with in vivo studies confirmed. In this study it was demonstrated that specific IgY powder (SIgY), produced by immunized hens via bacterin, was highly effective in inhibiting bacterial growth and adhesion, as well as exhibiting bactericidal and agglutination properties (P < 0.05). Notably, doses of 0.5 % and 1 % SIgY significantly enhanced both the height and width of intestinal villi, along with improving the villus height-to-crypt depth ratio when compared to the positive control group (P < 0.05). Furthermore, medium and high doses of SIgY were effective in preserving the integrity of the intestinal epithelium, as evidenced by a reduction in crypt depth and the number of goblet cells, which serve as important markers in the immune system (P < 0.01). Additionally, analyses of cecal and liver bacterial counts in response to the 0.5 % SIgY treatment revealed a significant reduction in C. jejuni counts compared to other challenged groups throughout the 28 d experiment (P < 0.01). Based on these results, it may be concluded that specific antibodies play a crucial role in maintaining the integrity of intestinal villi, support the health of the intestinal epithelium, and reduce the colonization of C. jejuni. These findings could form the basis for developing an economical and effective strategy to enhance poultry and human health in the context of C. jejuni infection.

Polysaccharides from Lycium barbarum, yam, and sunflower ameliorate colitis in a structure and intrinsic flora-dependent manner

Polysaccharides have been suggested to ameliorate metabolic diseases. However, their differential colitis-mitigating effects in mouse models with different colony structures remain poorly understood. Therefore, this study investigated the effects of polysaccharides from Lycium barbarum (LBP), sunflower (SP), and yam (YP) on colitis in C57BL/6 J (B6) mice born via vaginal delivery (VD) and in both caesarean section (CS)- and VD-born Institute of Cancer Research (ICR) mice. LBP was mainly composed of glucose (30.2 %), galactose (27.5 %), and arabinose (26.9 %). The main components of SP and YP were galacturonic acid (75.8 %) and glucose (98.1 %), respectively. Interestingly, LBP effectively alleviated body weight loss, reduced inflammatory cytokine levels, and restored intestinal barrier function in all three mouse models. Moreover, LBP decreased the abundance of norank_f__norank_o__Clostridia_UCG-014, Coriobacteriaceae_UCG-002, and norank_f_Eubacterium_coprostanoligenes_group in B6 mice, and the abundance of these genera positively correlated with pro-inflammatory cytokine levels. LBP increased the abundance of Lactobacillus, which was positively correlated with the levels of the protective factor, IL-10, in CS-born ICR mice. Collectively, our study suggests the potential application of LBP in the treatment of ulcerative colitis. We also provide an alternative method for restoring intestinal homeostasis in CS-born offspring.

Retrograded starch as colonic delivery carrier of taxifolin for treatment of DSS-induced ulcerative colitis in mice

Taxifolin, a natural dihydroflavonol compound, possesses notable anti-inflammatory properties and regulatory effects on intestinal microbiota. In this study, gelatinized-retrograded corn starch (GCS) was utilized as a carrier for colonic delivery of taxifolin, and its therapeutic efficacy against dextran sulfate sodium (DSS)-induced colitis in mice were systematically investigated. Taxifolin can integrate into the helical structure of starch, and the formation of GCS-Taxifolin complexes (GCS-Tax) significantly delayed the release of taxifolin in vitro. After oral administration of GCS-Tax, fecal excretion of taxifolin increased from 0.42 % to 10.89 % within 24 h compared to free taxifolin. Moreover, GCS-Tax facilitated the production of short-chain fatty acid in mice and effectively alleviated DSS-induced colitis symptoms, including weight loss, bloody stools, and colonic tissue damage. Additionally, GCS-Tax significantly suppressed proinflammatory factors such as interleukin-6 (IL-6), tumor necrosis factor-alpha (TNF-α), and lipopolysaccharide (LPS), while elevating anti-inflammatory interleukin-10 (IL-10) level in mice serum. Furthermore, it restored intestinal mucosal barrier function by upregulating the expression of Mucin 2, Occludin, and zonula occludens-1 (ZO-1), reducing Beclin 1 expression, and exhibited hepatoprotective effects by enhancing total antioxidant capacity (T-AOC), catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GSH-Px) activities. High-throughput sequencing analysis revealed that GCS-Tax improved intestinal flora diversity, reducing inflammation-related Bacterium 1 and Staphylococcus, while promoting the abundance of beneficial bacteria like Lachnospiraceae.

Banana Starch Nanoparticles Disrupt the Integrity of the Intestinal Barrier by Opening Tight Junctions in Mice

The banana-derived starch nanoparticles have been extensively used in food and biomedicine industries, due to their unique physicochemical properties and functional benefits. With their pervasive presence in food, people are significantly exposed to these nanoparticles, raising concerns about their potential health risks and impact on intestinal health. However, there is still limited understanding of the direct interaction between native banana starch nanoparticles (BSNs) and the intestinal systems. Here, it is demonstrated that BSNs can cause tight junctions to loosen, increase intestinal permeability, and disrupt the intestinal barrier. This increased permeability is closely linked to the size of BSNs, with smaller BSNs (d = 60 nm) having a stronger effect on permeation. Furthermore, the disruption of the intestinal barrier integrity caused by BSNs is connected to a reduced amount of tight junction proteins. Mechanistically, BSNs disrupt tight junctions by affecting mitochondrial function and activating myosin light chain kinase (MLCK) signaling pathway. These findings indicate that BSNs have the potential to pose health risks by compromising the integrity of the intestinal barrier, reminding the safety of food biopolymer nanoparticles in living organisms needs to be re-assessed.

Novel insights into the study of goblet cell hypersecretion in allergic rhinitis

Goblet cell hypersecretion is a hallmark of airway inflammation and is driven by complex neuroimmune regulation involving submucosal glands and goblet cells. Although studies have focused on mast cell degranulation as a critical driver of nasal secretion, the role of goblet cells in this process is relatively under-researched. In allergic airway inflammation, goblet cells exhibit metaplasia and hypersecretion. However, allergen exposure does not directly trigger goblet cell degranulation, raising questions regarding the underlying mechanisms of these reactions. The activation of enteric neurons promotes goblet cell degranulation by stimulating the calcitonin gene-related peptide (CGRP)-receptor active modification protein-1 (RAMP1) axis. Meanwhile, airway goblet cells express various neuropeptide receptors, and their activation by neuropeptides such as substance P and CGRP induces mucus secretion, exacerbating allergic rhinitis-associated hypersecretion. Thus, although previously less recognised, the neuron-goblet cell signalling axis plays a critical role in allergic rhinitis mucus secretion. This review highlights current research on the neuroimmune mechanisms underlying goblet cell metaplasia and degranulation, focusing on allergic rhinitis, so as to guide clinical treatment strategies.

Electrochemical biosensors for dopamine

Dopamine (DA), a key catecholamine, plays a pivotal role in the regulation of human cognition and emotions. It has profound effects on the hormonal, memory, and cardiovascular systems. Anomalies like Alzheimer's, Parkinson's, schizophrenia, and senile dementia are linked to abnormal DA levels. Consequently, the precise determination of DA levels in biological systems is critical for the accurate diagnosis and treatment of these disorders. Among all analytical techniques, electrochemical studies provide the most selective and highly sensitive methods for detecting DA in biological samples. Ascorbic acid and uric acid are two examples of small biomolecules that can obstruct the detection of DA in biological fluids. To address this issue, numerous attempts have been made to modify bare electrodes to separate the signals of these substances and enhance the electrocatalytic activity towards DA. Various surface modifiers, including coatings, conducting polymers, ionic liquids, nanomaterials, and inorganic complexes, have been employed in the modification process. Despite the reported success in DA detection using electrochemical sensors, many of these approaches are deemed too complex and costly for real-world applications. Therefore, this review aims to provide an overview of DA electrochemical biosensors that are practical for real-world applications.

Mechanistic study of the effect of a high-salt diet on the intestinal barrier

Despite the established link between chronic high salt diet (HSD) and an increase in gut inflammation, the effect of HSD on the integrity of the intestinal barrier remains understudied. The present study aims to investigate the impact of HSD on the intestinal barrier in rats, encompassing its mechanical, mucous, and immune components. Expression levels of intestinal tight junction proteins and mucin-2 (MUC2) in SD rats were analyzed using immunofluorescence. The expression area of goblet cell mucopolysaccharides was assessed through PAS staining. Additionally, serum D-lactic acid, SIgA, β-defensin, and colonic tissue cytokines were measured using ELISA. Rats fed with HSD exhibited decreased expression of tight junction proteins, particularly Occludin, resulting in impairment of the intestinal epithelial barrier and an elevated serum D-lactic acid level. Furthermore, a notable reduction in the expression of goblet cell mucopolysaccharides, along with lower β-defensin and MUC2 levels, was observed. Notably, the SIgA and immune-related cytokines were significantly reduced in the HSD group. HSD disrupts the intestinal barrier in rats, leading to increased permeability and the entry of inflammatory factors into the bloodstream. This finding suggests that HSD may contribute to the pathogenesis of various diseases.

Intestinal Effects of Brewers' Spent Grain Extract In Ovo (Gallus gallus)-A Pilot Study

Upcycling brewers' spent grain (BSG) into poultry feed needs to be optimized. Since broiler chickens inefficiently digest fiber, we created a water-soluble BSG extract (BSGE) to explore this fraction's potential nutritional benefits. We utilized intra-amniotic administration (in ovo) to target the gastrointestinal tract of broiler embryos. BSGE increased villus surface area and goblet cell quantity and size, implying improved duodenal development. The extract also changed cecal Escherichia coli (E. coli) and Clostridium abundances. Synchrotron X-ray fluorescence microscopy, along with zinc and iron transporter relative expression, did not reveal significant changes by BSGE. These findings highlight the potential for BSGE to be a functional feed component, underscoring the potential value of upcycling this byproduct. This pilot study supports future work exploring the impact of BSGE within feed and its effects over long-term consumption.

Multi-omics perspective: mechanisms of gastrointestinal injury repair

In this review, we examine the significance of multi-omics technologies in understanding the plethora of intricate processes that activate gastrointestinal (GI) injury repair. Multi-omics, which includes genomics, transcriptomics, proteomics, and metabolomics, allows intricate mapping of cellular responses and molecular pathways involved in GI repair. We highlight the potential of multi-omics to discover previously unknown therapeutic targets or elucidate the molecular basis of the pathogenesis of GI. Furthermore, we explore the possibilities of integrating omics data to improve prediction models, and summarize the state-of-the-art technological developments and persisting obstacles that hinder the translation of multi-omics into clinical practice. Finally, innovative multi-omics approaches that can improve patient outcomes and advance therapeutic strategies in GI medicine are discussed.

Tirzepatide, a dual agonist of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), positively impacts the altered microbiota of obese, diabetic, ovariectomized mice

The study aimed to verify the effect of Tirzepatide (Tzp, a dual agonist GIP/GLP-1) on intestinal health and microbiota balance in an obese diabetic ovariectomized (Ovx) mice model. Female C57BL/6 mice with Ovx and diet-induced obesity with diabetes were treated with Tzp (10 nmol/kg) for four weeks. Control (C) and obese-diabetic subgroups (Od) were formed (group abbreviations: O, Ovx; T, Tzp; n = 30/group): C, CT, CO, COT, Od, OdT, OdO, OdOT. The ileum was structurally and molecularly studied, and cecal feces had microbial DNA determined. Tzp improved the intestinal barrier structure and protection. Cldn12 (Claudin 12) increased, and Muc2 (Mucin 2) decreased. JamA (junctional adhesion molecules) and Ocln (Occludin) increased. Tzp mitigated macrophage activation and inflammation, altered composition, and the contribution to microbiota: Firmicutes decreased, and Bacteroidetes increased, changing the Firmicutes / Bacteroidetes ratio. Proteobacteria, Actinobacteria, Bifidobacterium, and Clostridium increased. In addition, Bacteroides, Prevotella, and Akkermansia increased. PCA indicated a significant action of Cd14, Muc2, and Tlr4 on CO and Il17 on OdO; Il10, Cd206, Cd12, Ocln, and JamA in Od. Bacteroides, Bifidobacterium, Clostridium, Actinobacteria, and Bacteroides were enhanced in CT and COT, Provotella, Proteobacteria, and Firmicutes in CO, Od, OdT, OdO, and Akkermansia in OdOT. In conclusion, the intestinal barrier function in our model is compromised by alterations in phylogenetic diversity and intestinal microbiota, which characterize dysbiosis and potentially enable the influx of toxins into other tissues. Treatment with Tzp demonstrated the ability to reverse intestinal dysbiosis, help repair intestinal barrier integrity, and mitigate possible endotoxemia through anti-inflammatory signaling pathways.