Intestinal Defense Research Articles

The Pivotal Role of Aryl Hydrocarbon Receptor-Regulated Tight Junction Proteins and Innate Immunity on the Synergistic Effects of Postbiotic Butyrate and Active Vitamin D3 to Defense against Microbial Invasion in Salmonella Colitis.

Our recent report illustrated the unitedly advantageous effects of postbiotic butyrate on active vitamin D3 (VD3)-orchestrated innate immunity in Salmonella colitis. There is growing awareness that aryl hydrocarbon receptor (AhR) can regulate intestinal immunity and barrier function, through modulating cecal inflammation and junction proteins expression. Hence, we researched the participation of AhR-regulated tight junction functions on the united effects of butyrate and VD3 on intestinal defense to Salmonella infection. Salmonella colitis model were elicited by oral gavage with 1 × 108 CFU of a S. typhimurium wild-type strain SL1344 in C57BL/6 mice. Before and after the colitis generation, mice were fed with butyrate and/or VD3 by oral gavage in the absence or presence of intraperitoneal injection of AhR inhibitor for 4 and 7 days, respectively. We observed that butyrate and VD3 could concert together to reduce the invasion of Salmonella in colitis mice by enhancing cecal cytokines and antimicrobial peptides expression and reducing zonulin and claudin-2 protein expressions in mucosal stain, compared to single treatment, which were counteracted by AhR inhibitor. It implies that AhR is involved in the united effects of butyrate and VD3 on the intestinal defense to Salmonella infection in colitis mice. This study discloses the promising alternative therapy of combining postbiotic and VD3 for invasive Salmonellosis and the pivotal role of AhR pathway.

Gut-Derived Metabolites from Dietary Tryptophan Supplementation Quench Intestinal Inflammation through the AMPK-SIRT1-Autophagy Pathway

Tryptophan has drawn wide attention due to its involvement in improving intestinal immune defense directly and indirectly by regulating metabolic pathways. The study aims to elucidate the potential modulating roles of tryptophan to protect against intestinal inflammation and elucidate the underlying molecular mechanisms. The protective effects of tryptophan against intestinal inflammation are examined in the lipopolysaccharide (LPS)-induced inflammatory model. We first found that tryptophan markedly (p < 0.01) inhibited proinflammatory cytokines production and nuclear factor κB (NF-κB) pathway activation upon LPS challenge. Next, we demonstrated that tryptophan (p < 0.05) attenuated LPS-caused intestinal mucosal barrier damage by increasing the number of goblet cells, mucins, and antimicrobial peptides (AMPs) in the ileum of mice. In addition, tryptophan (p < 0.05) inhibited LPS-induced autophagic flux through the AMP-activated protein kinase (AMPK)-sirtuin 1 (SIRT1) pathway in the intestinal systems to maintain autophagy homeostasis. Meanwhile, tryptophan also reshaped the gut microbiota composition in LPS-challenge mice by increasing the abundance of short-chain fatty acid (SCFA)-producing bacteria such as Acetivibrio (0.053 ± 0.017 to 0.21 ± 0.0041%). Notably, dietary tryptophan resulted in the activation of metabolic pathways during the inflammatory response. Furthermore, exogenous treatment of tryptophan metabolites kynurenine (Kyn) and 5-HT in porcine intestinal epithelial cells (IPEC-J2 cells) reproduced similar protective effects as tryptophan to attenuate LPS-induced intestinal inflammation through regulating the AMPK-SIRT1-autophagy. Taken together, the present study indicates that tryptophan exhibits intestinal protective and immunoregulatory effects resulting from the activation of metabolic pathways, maintenance of gut mucosal barrier integrity, microbiota composition, and AMPK-SIRT1-autophagy level.

CDC1-derived IL-27 regulates small intestinal CD4+ T cell homeostasis in mice.

The small intestinal lamina propria contains large numbers of IFNγ-producing T helper (Th1) cells that play important roles in intestinal homeostasis and host defense, but the mechanisms underlying their development remain poorly understood. Here, we demonstrate that Th1 cells accumulate in the SI-LP after weaning and are maintained there long term. While both Th17 and Th1 cell accumulation in the SI-LP was microbiota dependent, Th1 cell accumulation uniquely required IL-27 and MHCII expression by cDC1. This reflected a requirement for IL-27 signaling in the priming of Th1 cells rather than for their maintenance once in the mucosa. cDC1-derived IL-27 was essential for maintaining the Th1-Th17 balance within the SI-LP, and in its absence, remaining Th1 cells expressed enhanced levels of Th17 signature genes. In conclusion, we identify cDC1-derived IL-27 as a key regulator of SI-LP Th1-Th17 cell homeostasis.

Active eosinophils regulate host defence and immune responses in colitis

In the past decade, single-cell transcriptomics has helped to uncover new cell types and states and led to the construction of a cellular compendium of health and disease. Despite this progress, some difficult-to-sequence cells remain absent from tissue atlases. Eosinophils—elusive granulocytes that are implicated in a plethora of human pathologies1–5—are among these uncharted cell types. The heterogeneity of eosinophils and the gene programs that underpin their pleiotropic functions remain poorly understood. Here we provide a comprehensive single-cell transcriptomic profiling of mouse eosinophils. We identify an active and a basal population of intestinal eosinophils, which differ in their transcriptome, surface proteome and spatial localization. By means of a genome-wide CRISPR inhibition screen and functional assays, we reveal a mechanism by which interleukin-33 (IL-33) and interferon-γ (IFNγ) induce the accumulation of active eosinophils in the inflamed colon. Active eosinophils are endowed with bactericidal and T cell regulatory activity, and express the co-stimulatory molecules CD80 and PD-L1. Notably, active eosinophils are enriched in the lamina propria of a small cohort of patients with inflammatory bowel disease, and are closely associated with CD4+ T cells. Our findings provide insights into the biology of eosinophils and highlight the crucial contribution of this cell type to intestinal homeostasis, immune regulation and host defence. Furthermore, we lay a framework for the characterization of eosinophils in human gastrointestinal diseases.

Intraepithelial lymphocytes in the pig intestine: T cell and innate lymphoid cell contributions to intestinal barrier immunity.

Intraepithelial lymphocytes (IELs) include T cells and innate lymphoid cells that are important mediators of intestinal immunity and barrier defense, yet most knowledge of IELs is derived from the study of humans and rodent models. Pigs are an important global food source and promising biomedical model, yet relatively little is known about IELs in the porcine intestine, especially during formative ages of intestinal development. Due to the biological significance of IELs, global importance of pig health, and potential of early life events to influence IELs, we collate current knowledge of porcine IEL functional and phenotypic maturation in the context of the developing intestinal tract and outline areas where further research is needed. Based on available findings, we formulate probable implications of IELs on intestinal and overall health outcomes and highlight key findings in relation to human IELs to emphasize potential applicability of pigs as a biomedical model for intestinal IEL research. Review of current literature suggests the study of porcine intestinal IELs as an exciting research frontier with dual application for betterment of animal and human health.

Weaning diet supplemented with health-promoting feed additives influences microbiota and immune response in piglets challenged with Salmonella

The aim of this study was to evaluate the potential of micronutrients and feed additives to modulate intestinal microbiota and systemic and mucosal immune responses in weaned pigs infected with Salmonella. At weaning, 32 litters of 12 piglets each were allocated to four dietary treatments: 1) control diet (CTRL), 2) CTRL supplemented with chlortetracycline (ATB), 3) CTRL supplemented with a cocktail of feed additives (CKTL); and 4) CKTL diet containing bovine colostrum in replacement of spray-dry animal plasma (CKTL+COL). The CKTL supplement included cranberry extract, encapsulated carvacrol and yeast-derived products and an enriched selenium and vitamin premix. Three weeks after weaning, four pigs per litter were orally inoculated with Salmonella Typhimurium DT104. Half of them were euthanized 3 days post-infection (dpi) and the other half, 7 dpi. The expression of IL6, TNF, IL8, monocyte chemoattractant protein 1 (MCP1), IFNG, cyclooxygenase 2 (COX2), glutathione peroxidase 2 (GPX2) and β-defensin 2 (DEFB2) showed a peaked response at 3 dpi (P < 0.05). Results also revealed that DEFB2 expression was higher at 3 dpi in CTRL and CKTL groups than in ATB (P = 0.01 and 0.06, respectively) while GPX2 gene was markedly increased at 3 and 7 dpi in pigs fed CKTL or CKTL+COL diet compared to CTRL pigs (P < 0.05). In piglets fed CKTL or CKTL+COL diet, intestinal changes in microbial communities were less pronounced after exposure to Salmonella compared to CTRL and progressed faster toward the status before Salmonella challenge (AMOVA P < 0.01). Furthermore, the relative abundance of several families was either up- or down-regulated in pigs fed CKTL or CKTL+COL diet after Salmonella challenge. In conclusion, weaning diet enriched with bovine colostrum, vitamins and mixture of feed additives mitigated the influence of Salmonella infection on intestinal microbial populations and modulate systemic and intestinal immune defences.

The Intestinal Immune Defense System in Insects

Over a long period of evolution, insects have developed unique intestinal defenses against invasion by foreign microorganisms, including physical defenses and immune responses. The physical defenses of the insect gut consist mainly of the peritrophic matrix (PM) and mucus layer, which are the first barriers to pathogens. Gut microbes also prevent the colonization of pathogens. Importantly, the immune-deficiency (Imd) pathways produce antimicrobial peptides to eliminate pathogens; mechanisms related to reactive oxygen species are another important pathway for insect intestinal immunity. The janus kinase/STAT signaling pathway is involved in intestinal immunity by producing bactericidal substances and regulating tissue repair. Melanization can produce many bactericidal active substances into the intestine; meanwhile, there are multiple responses in the intestine to fight against viral and parasitic infections. Furthermore, intestinal stem cells (ISCs) are also indispensable in intestinal immunity. Only the coordinated combination of the intestinal immune defense system and intestinal tissue renewal can effectively defend against pathogenic microorganisms.

GABAergic Neuromuscular Junction Suppresses Intestinal Defense of Caenorhabditis elegans by Attenuating Muscular Oxidative Phosphorylation.

Innate immunity is an ancient and evolutionarily conserved system that constitutes the first line of host defense against invading microbes. We previously determined that the GABAergic neuromuscular junction (NMJ) suppresses intestinal innate immunity via muscular insulin signaling. Here, we found that a muscular mitochondrial oxidative phosphorylation pathway of Caenorhabditis elegans is involved in GABAergic NMJs-mediated intestinal defense. Deficiency in GABAergic neurotransmission increases reactive oxygen species (ROS) abundance and inhibits the nuclear translocation of SKN-1, whereas exogenous GABA administration represses it. SKN-1 is an important transcription factor involved in oxidative stress and the innate immune response. Moreover, deficiency in GABAergic postsynaptic UNC-49/GABAAR robustly promotes the mitochondrial function of GABAergic postsynaptic muscle cells, which may contribute to the muscular ROS decrease and intestinal SKN-1 suppression, ultimately inhibiting the intestinal defense of C. elegans. Our findings reveal a potential role of muscle mitochondrial ROS in intestinal defense in vivo and expand our understanding of mechanisms of intestinal innate immunity.

Review of the Zoonotic Importance of Salmonellosis and Associated Risk Factors

Salmonella is one of the most common and significant human and animal food-borne pathogens that cause salmonellosis, which has high medical and monetary costs. Salmonella has a big impact on public health because it can spread zoonotic and foodborne diseases to people. Many domestic and wild animals intestinal tracts serve as the main reservoir for Salmonella, which can result in the direct or indirect contamination of a variety of foods with fecal organisms. Salmonellae are etiological agents of diarrheal and systemic infections. They can be shed in large numbers on the faces of clinical cases and carrier animals, causing contamination of the environment and frequently resulting in subclinical infections. Infection in food animals often leads to contamination of meat, eggs, milk and cheese. The organism can also spread through direct contact with infected humans, animals, or feces contaminated environments. Infected food handlers may also act as a source of contamination for foodstuffs, because of the increasing antibiotic resistance of organisms and companion animals, animals are an important source of Salmonella infection for humans. Salmonella can colonize its hosts by invading, adhering, and bypassing the host’s intestinal defense mechanisms, such as gastric acid, thanks to a variety of virulence markers and determinants, including flagella, capsule, plasmids, adhesion systems, and secretion systems. Diagnosis is based on the isolation of the organism either from tissues collected aseptically at necropsy or from faces, rectal swabs or environmental samples, food products, and feedstuffs; prior or current infection of animals by some agents may also be diagnosed serologically.

The anti-aging effects of Renshen Guben on thyrotoxicosis mice: Improving immunosenescence, hypoproteinemia, lipotoxicity, and intestinal flora.

With the rapid aging of the population, the control of age-related disease susceptibility and prognosis faces greater challenges. There is an urgent need for a strategy to maintain the vitality of elderly people. In this study, the effect of Renshen Guben (RSGB) oral liquid was investigated on an accelerated aging mice model of thyrotoxicosis by conventional detection methods combined with multiomics technology. The results showed that RSGB increased the number of neutrophils and lymphocytes, enhanced the function of lymphocytes, and increased the levels of complement and antimicrobial peptides, which indicated that RSGB improved the immunity of thyrotoxicosis mice at the cellular and molecular levels. RSGB corrected malnutrition in thyrotoxicosis mice by improving anemia, hypoalbuminemia, ion transporters, and vitamin-binding proteins. RSGB significantly reduced the lipotoxicity by reducing the level of fatty acids, triglyceride, sphingolipids, and glucocorticoids, thus increasing the level of docosapentaenoic acid (DPA) and bile acids, which contributed to improve immunosenescence. The intestinal defense ability of thyrotoxicosis mice was enhanced with the increase of bile acids and lactic acid bacteria by the RSGB treatment. The plant metabolomics analysis showed that there were various active components in RSGB oral liquid and medicated serum, including terpenoids, phenolic acids, flavonoids, tannin, alkaloids, organic acids, phenolamines, amino acids, and others. They have antioxidant, immune regulation, and anti-aging effects, which was the material basis of RSGB. Totally, RSGB protected the thyrotoxicosis mice against aging by improving immunosenescence, hypoproteinemia, lipotoxicity, and the intestinal flora. It will be beneficial for improving the disease susceptibility and prognosis of the elderly.

Defects in the expression of colonic host defense factors associate with barrier dysfunction induced by a high-fat/high-cholesterol diet.

The effect of Western diets in the gastrointestinal system is largely mediated by their ability to promote alterations in the immunity and physiology of the intestinal epithelium, and to affect the composition of the commensal microbiota. To investigate the response of the colonic epithelium to high-fat/high-cholesterol diets (HFHCDs), we evaluated the synthesis of host defense factors involved in the maintenance of the colonic homeostasis. C57BL/6 mice were fed an HFHCD for 3 weeks and their colons were evaluated for histopathology, gene expression, and microbiota composition. In addition, intestinal permeability and susceptibility to Citrobacter rodentium were also studied. HFHCD caused colonic hyperplasia, loss of goblet cells, thinning of the mucus layer, moderate changes in the composition of the intestinal microbiota, and an increase in intestinal permeability. Gene expression analyses revealed significant drops in the transcript levels of Muc1, Muc2, Agr2, Atoh1, Spdef, Ang4, Camp, Tff3, Dmbt1, Fcgbp, Saa3, and Retnlb. The goblet cell granules of HFHCD-fed mice were devoid of Relmβ and Tff3, indicating defective production of those two factors critical for intestinal epithelial defense and homeostasis. In correspondence with these defects, colonic bacteria were in close contact with, and invading the epithelium. Fecal shedding of C. rodentium showed an increased bacterial burden in HFHCD-fed animals accompanied by increased epithelial damage. Collectively, our results show that HFHCD perturbs the synthesis of colonic host defense factors, which associate with alterations in the commensal microbiota, the integrity of the intestinal barrier, and the host's susceptibility to enteric infections.

Specific activation of hypoxia-inducible factor-2α by propionate metabolism via a β-oxidation-like pathway stimulates MUC2 production in intestinal goblet cells

Microbiota-derived short-chain fatty acids (SCFAs) are known to stimulate mucin expression in the intestine, which contributes to the gut mucosal immune responses, and the gut mucosal immune system extends to the brain and other organs through several axes. Hypoxia-inducible factors (HIFs), especially HIF-1α, are known to act as the master regulator of mucin expression, however, underlying mechanism of mucin expression during hypoxia by SCFAs remains unclear. In this study, we investigated the mechanism of MUC2 expression by propionate, an SCFA, in intestinal goblet cells. The real time oxygen consumption rate (OCR) and ATPase activity were measured to investigate the induction of hypoxia by propionate. Using 2-dimensional electrophoresis (2-DE), microarray analysis, and siRNA-induced gene silencing, we found that propionate is metabolized via a β-oxidation-like pathway instead of the vitamin B12-dependent carboxylation pathway (also known as the methylmalonyl pathway). We verified the results by analyzing several intermediates in the pathway using LC-MS and GC-MS. Propionate metabolism via the β-oxidation-like pathway leads to the depletion of oxygen and thereby induces hypoxia. Analysis of HIFs revealed that HIF-2α is the primary HIF whose activation is induced by propionate metabolism in a hypoxic environment and that HIF-2α regulates the expression of MUC2. Thus, hypoxia induced during propionate metabolism via a β-oxidation-like pathway specifically activates HIF-2α, stimulating MUC2 production in LS 174 T goblet cells. Our findings show that propionate-induced selective HIF-2α stimulation contributes to intestinal mucosal defense.

Computational prediction and experimental validation of Salmonella Typhimurium SopE-mediated fine-tuning of autophagy in intestinal epithelial cells.

Macroautophagy is a ubiquitous homeostasis and health-promoting recycling process of eukaryotic cells, targeting misfolded proteins, damaged organelles and intracellular infectious agents. Some intracellular pathogens such as Salmonella enterica serovar Typhimurium hijack this process during pathogenesis. Here we investigate potential protein-protein interactions between host transcription factors and secreted effector proteins of Salmonella and their effect on host gene transcription. A systems-level analysis identified Salmonella effector proteins that had the potential to affect core autophagy gene regulation. The effect of a SPI-1 effector protein, SopE, that was predicted to interact with regulatory proteins of the autophagy process, was investigated to validate our approach. We then confirmed experimentally that SopE can directly bind to SP1, a host transcription factor, which modulates the expression of the autophagy gene MAP1LC3B. We also revealed that SopE might have a double role in the modulation of autophagy: Following initial increase of MAP1LC3B transcription triggered by Salmonella infection, subsequent decrease in MAP1LC3B transcription at 6h post-infection was SopE-dependent. SopE also played a role in modulation of the autophagy flux machinery, in particular MAP1LC3B and p62 autophagy proteins, depending on the level of autophagy already taking place. Upon typical infection of epithelial cells, the autophagic flux is increased. However, when autophagy was chemically induced prior to infection, SopE dampened the autophagic flux. The same was also observed when most of the intracellular Salmonella cells were not associated with the SCV (strain lacking sifA) regardless of the autophagy induction status before infection. We demonstrated how regulatory network analysis can be used to better characterise the impact of pathogenic effector proteins, in this case, Salmonella. This study complements previous work in which we had demonstrated that specific pathogen effectors can affect the autophagy process through direct interaction with autophagy proteins. Here we show that effector proteins can also influence the upstream regulation of the process. Such interdisciplinary studies can increase our understanding of the infection process and point out targets important in intestinal epithelial cell defense.

Can use of probiotics drugs cause fungemia? – a literature review

Commercially, there are many products sold as probiotics composed by Sacharomyces boulardii, with probiotic drugs being those that are widely used in different clinical situations. The probiotic efficacy of these agents is proven in many studies, as well as their safety in normal use situations. However, there have been some reports of fungemias related to the use of these probiotics in hospitals associated with some factors. Therefore, our objective is to review the knowledge about this association, focusing on the factors that provide it and the development mechanisms. For the development of fungemia associated with the use of probiotics, it is observed that it has greater development potential in patients using a central venous catheter. Although this is the main factor, others that reduce the patient's immune status, as well as reduce the intestinal defense barriers, contribute to this process, increasing the risk of fungemia. Despite the well-documented benefits of probiotics, their use must be carefully evaluated for each patient, due to factors that contribute to associate the use of probiotic drugs with the risk of developing bloodstream infection by S. boulardii. It is necessary, therefore, to include protocols that generate alerts about this risk and establish preventive measures.

Dietary supplementation of sulfur amino acids improves intestinal immunity to Eimeria in broilers treated with anti-interleukin-10 antibody.

Oral antibody to interleukin-10 (anti-IL-10) enhances the intestinal immune defense against Eimeria. The sulfur amino acids methionine and cysteine (M+C) play essential roles in inducing and maintaining protective immune responses during intestinal infections. Hence, increased dietary M+C may support the anti-IL-10-induced intestinal immunity to Eimeria. Broilers (n = 640) were arranged in a 2 × 2 × 2 factorial design with 2 levels of each of the 3 main factors: dietary standardized ileal digestible (SID) M+C levels (0.6% or 0.8%), dietary anti-IL-10 supplementation (with or without), and coccidiosis challenge (control or challenge). Briefly, the broilers were supplied with either 0.6% or 0.8% SID M+C, each with or without anti-IL-10 (300 μg/kg), from d 10 to 21. On d 14, broilers from each diet were gavaged with either PBS or Eimeria. The resulting Eimeria infection induced fecal oocyst shedding and intestinal lesions. Broilers fed 0.8% SID M+C (main effects, P ≤ 0.05) had decreased feed-to-gain ratio, increased duodenum and cecum luminal anti-Eimeria IgA titers, and decreased fecal oocyst counts, when compared to 0.6% SID M+C. The supplementation of anti-IL-10 (main effects, P ≤ 0.05) increased cecum luminal total IgA concentration and decreased cecum lesions. Interactions (P ≤ 0.05) were detected for growth performance and cecum luminal IFN-γ. Briefly, the highest body weight gain and feed intake were reached in PBS-gavaged broilers fed 0.8% SID M+C with no anti-IL-10 and in Eimeria-challenged broilers fed 0.8% SID M+C with anti-IL-10. In Eimeria-infected broilers, anti-IL-10 increased intestinal luminal IFN-γ and body weight gain only at 0.8% SID M+C. Collectively, anti-IL-10 increased intestinal luminal IFN-γ levels, decreased cecum lesions and restored growth only when fed with adequate amounts of sulfur amino acids. Our findings underscore the importance of providing sufficient essential nutrients to support the anti-IL-10 induced immunity against coccidiosis.

Microbiome in Critical Care: An Unconventional and Unknown Ally.

The digestive tract represents an interface between the external environment and the body where the interaction of a complex polymicrobial ecology has an important influence on health and disease. The physiological mechanisms that are altered during hospitalization and in the intensive care unit (ICU) contribute to the pathobiota's growth. Intestinal dysbiosis occurs within hours of being admitted to ICU. This may be due to different factors, such as alterations of normal intestinal transit, administration of various medications, or alterations in the intestinal wall, which causes a cascade of events that will lead to the increase of nitrates and decrease of oxygen concentration, and the liberation of free radicals. This work aims to report the latest updates on the microbiota's contribution to developing sepsis in patients in the ICU department. In this short review, the latest scientific findings on the mechanisms of intestinal immune defenses performed both locally and systemically have been reviewed. Additionally, we considered it necessary to review the literature on the basis of the many studies carried out on the microbiota in the critically ill as a prevention to the spread of the infection in these patients. This review has been written to answer four main questions: 1- What are the main intestinal flora's defense mechanisms that help us to prevent the risk of developing systemic diseases? 2- What are the main Systemic Abnormalities of Dysbiosis? 3- What are the Modern Strategies Used in ICU to Prevent the Infection Spreading? 4- What is the Relationship between COVID-19 and Microbiota? We reviewed 72 articles using the combination of following keywords: "microbiota" and "microbiota" and "intensive care", "intensive care" and "gut", "critical illness", "microbiota" and "critical care", "microbiota" and "sepsis", "microbiota" and "infection", and "gastrointestinal immunity" in: Cochrane Controlled Trials Register, Cochrane Library, Medline and Pubmed, Google Scholar, Ovid/Wiley. Moreover, we also consulted the site ClinicalTrials.com to find out studies that have been recently conducted or are currently ongoing. The critical illness can alter intestinal bacterial flora leading to homeostasis disequilibrium. Despite numerous mechanisms, such as epithelial cells with calciform cells that together build a mechanical barrier for pathogenic bacteria, the presence of mucous associated lymphoid tissue (MALT) which stimulates an immune response through the production of interferon-gamma (IFN-y) and THN-a or or from the production of anti-inflammatory cytokines produced by lymphocytes Thelper 2. But these defenses can be altered following hospitalization in ICU and lead to serious complications, such as acute respiratory distress syndrome (ARDS), health care associated pneumonia (HAP) and ventilator associated pneumonia (VAP), systemic infection and multiple organ failure (MOF), but also to the development of coronary artery disease (CAD). In addition, the microbiota has a significant impact on the development of intestinal complications and the severity of the SARS-COVID-19 patients. The microbiota is recognized as one of the important factors that can worsen the clinical conditions of patients who are already very frail in the intensive care unit. At the same time, the microbiota also plays a crucial role in the prevention of ICU-associated complications. By using the resources that are available, such as probiotics, synbiotics or fecal microbiota transplantation (FMT), we can preserve the integrity of the microbiota and the GUT, which will later help maintain homeostasis in ICU patients.

The effect of a polystyrene nanoplastic on the intestinal microbes and oxidative stress defense of the freshwater crayfish, Procambarus clarkii

The widespread generation and accumulation of plastic waste has become a globally recognized problem. However, there are limited reports on the adverse effects of nanomaterials on freshwater crustaceans. This study tested the acute effects of different concentrations (0, 5, 10, and 20 mg/L) after 48 h exposure of 75 nm polystyrene nanoplastic on intestinal microbes, and oxidative stress parameters of freshwater crayfish, Procambarus clarkii. High-throughput sequencing analysis revealed the richness, diversity, and composition of intestinal microbiota in P. clarkii exposed to polystyrene nanoplastic. At the genus level, abundances of Lactobacillus, Faecalibaculum, Niveibacterium, and Candidatus Bacilloplasma were significantly different. The reduced abundance of Lactobacillus could affect the balance of intestinal microbes through quantitative disadvantage, which may lead to reduced immunity of P. clarkii. Streptococcus salivarius, Clostridium butyricum and Lachnospiraceae bacterium10–1 in intestinal tract reached maximum abundance at a polystyrene concentration of 20 mg/L. The increase in the number of some pathogenic bacteria may upset the balance of intestinal microorganisms through the number of dominance, and the decrease in the relative abundance of lactic acid bacteria. Probiotics, such as Lactobacillus salivarius, Lactobacillus murinus, Lactobacillus gasseri, Lactobacillus reuteri, Lactobacillus iners AB-1, and Lactobacillus crispatus in the intestinal tract reached the lowest value at a concentration of 10 mg/L. The reduced abundance of Lactobacillus can affect the balance of intestinal microbes through quantitative disadvantage, which may lead to reduced immunity in P. clarkii. At nanoplastic 10 mg/L, the relative abundance of intestinal pathogens increased, while the relative abundance of lactic acid bacteria and other probiotics decreased. With increases in nanoplastic concentrations, the values of glutathione (GSH), superoxide dismutase (SOD), acid phosphatase (ACP), lysozyme (LZM), alkaline phosphatase (AKP), peroxidase (POD), glutathione peroxidase (GPX), and protein carbonylation were significantly changed. Our data suggested that Lactobacillus may play an adjunctive role in the treatment of oxidative stress in P. clarkii exposed to 75 nm polystyrene. This study represents an important step towards a better understanding of the toxic effects of nanoplastics on aquatic crustaceans.

Effect of Zeolite Supplementation on Gene Expression in the Intestinal Mucosa in the Context of Immunosafety Support in Poultry

Zeolite is an effective and non-toxic silicate mineral. Its properties are widely used in industry due to its sorption and ion exchange properties. Due to its excellent chemical properties, it has also great potential in poultry production as a food additive or supplement to bedding. This is of great importance for the biosafety and hygiene of production. The study aimed to analyse the effects of simultaneous application of zeolite to feed and bedding on production parameters and expression of genes related to intestinal tightness, organism defence, and immune response. Male Ross 308 broiler chickens were used in the experiment. In the experimental group, an external factor in the form of a powdery zeolite was used for feed and pelleted bedding. On the day of slaughter, the caecal mucosa was collected for gene expression analysis. We showed no significant changes in the tissue composition of the carcasses, but zeolite had a beneficial effect on the carcass yield. The analysis of the immune gene panel showed a significant increase in the expression of the interleukins and interferons genes. We have demonstrated the effect of zeolite on the improvement of the intestinal barrier and increasing the tightness of the intestines. There were no changes in gene expression related to the host’s defence against infections; therefore, based on the obtained results, it was concluded that zeolite can be considered an immunomodulating factor of the immune system.

Increased expression of OLFM4 and lysozyme during necrotizing enterocolitis in neonates: an observational research study

BackgroundIn neonatal patients with necrotizing enterocolitis (NEC) the inflammatory response is mediated by a plurality of different proteins. The proteins olfactomedin 4 (OLFM4) and lysozyme (LYZ) are part of the intestinal mucosal defense and especially OLFM4 has rarely been evaluated in neonatal gastrointestinal diseases. The aim of this study was to analyze whether expression levels of both proteins of innate immunity, OLFM4 and lysozyme, were increased during NEC in neonates.MethodsIntestinal tissues of patients with NEC were examined with immunohistochemical staining of formalin-fixed and paraffin-embedded sections of resected tissue using antibodies against OLFM4 and lysozyme. Staining-positive tissues were semi-quantitatively scored from 0 (no staining), 1 (weak staining), 2 (moderate staining) to 3 (highly intense staining) by two individual investigators. Intestinal tissue of infants with volvulus was used as a control as other intestinal tissue without major inflammation was not available.ResultsBoth applied antibodies against OLFM4 showed different staining patterns with higher staining intensity of the antibody OLFM4 (D1E4M). OLFM4 (median score of the antibody OLFM4 (D1E4M): 3.0) and lysozyme (median score: 3.0) are highly expressed in intestinal and immune cells during NEC. Expression of OLFM4 and lysozyme in the control samples with volvulus was observable but significantly lower (median score of the antibody OLFM4 (D1E4M): 1.25; median score of the antibody against LYZ: 2.0; p = 0.033 and p = 0.037, respectively).ConclusionsBoth proteins, OLFM4 and lysozyme, may play a role in the pathogenesis of NEC in neonatal patients, but the exact mechanisms of OLFM4 and lysozyme function and their role in immunological responses have not yet been resolved in detail. These observations add new insights as basis for further large-scale population research.

The Long Non-Coding RNA Nostrill Regulates Transcription of Irf7 Through Interaction With NF-κB p65 to Enhance Intestinal Epithelial Defense Against Cryptosporidium parvum.

The cells of the intestinal epithelium establish the frontline for host defense against pathogens in the gastrointestinal tract and play a vital role in the initiation of the immune response. Increasing evidence supports the role of long non-coding RNAs (lncRNAs) as critical regulators of diverse cellular processes, however, their role in antimicrobial host defense is incompletely understood. In this study, we provide evidence that the lncRNA Nostrill is upregulated in the intestinal epithelium following infection by Cryptosporidium parvum, a globally prevalent apicomplexan parasite that causes significant diarrheal disease and an important opportunistic pathogen in the immunocompromised and AIDS patients. Induction of Nostrill in infected intestinal epithelial cells was triggered by NF-κB signaling and was observed to enhance epithelial defense by decreasing parasitic infection burden. Nostrill participates in the transcriptional regulation of C. parvum-induced Irf7 expression through interactions with NF-κB p65, and induction of Nostrill promotes epigenetic histone modifications and occupancy of RNA polymerase II at the Irf7 promoter. Our data suggest that the induction of Nostrill promotes antiparasitic defense against C. parvum and enhances intestinal epithelial antimicrobial defense through contributions to transcriptional regulation of immune-related genes, such as Irf7.