A co-culture model of the developing small intestine offers new insight in the early immunomodulation of enterocytes and macrophages by Lactobacillus spp. through STAT1 and NF-kB p65 translocation

Assessing immunogenicity of CRISPR-NCas9 engineered strain against porcine epidemic diarrhea virus

Porcine epidemic diarrhea (PED) caused by porcine epidemic diarrhea virus (PEDV), is an acute and highly infectious disease, resulting in substantial economic losses in the pig industry. Given that PEDV primarily infects the mucosal surfaces of the intestinal tract, it is crucial to improve the mucosal immunity to prevent viral invasion. Lactic acid bacteria (LAB) oral vaccines offer unique advantages and potential applications in combatting mucosal infectious diseases, making them an ideal approach for controlling PED outbreaks. However, traditional LAB oral vaccines use plasmids for exogenous protein expression and antibiotic genes as selection markers. Antibiotic genes can be diffused through transposition, transfer, or homologous recombination, resulting in the generation of drug-resistant strains. To overcome these issues, genome-editing technology has been developed to achieve gene expression in LAB genomes. In this study, we used the CRISPR-NCas9 system to integrate the PEDV S1 gene into the genome of alanine racemase-deficient Lactobacillus paracasei △Alr HLJ-27 (L. paracasei △Alr HLJ-27) at the thymidylate synthase (thyA) site, generating a strain, S1/△Alr HLJ-27. We conducted immunization assays in mice and piglets to evaluate the level of immune response and evaluated its protective effect against PEDV through challenge tests in piglets. Oral administration of the strain S1/△Alr HLJ-27 in mice and piglets elicited mucosal, humoral, and cellular immune responses. The strain also exhibited a certain level of resistance against PEDV infection in piglets. These results demonstrate the potential of S1/△Alr HLJ-27 as an oral vaccine candidate for PEDV control. KEY POINTS: • A strain S1/△Alr HLJ-27 was constructed as the candidate for an oral vaccine. • Immunogenicity response and challenge test was carried out to analyze the ability of the strain. • The strain S1/△Alr HLJ-27 could provide protection for piglets to a certain extent.

Enhanced tight junction in Caco-2 cells by the pretreatment with Lactobacillus johnsonii strain MG

We investigated roles of Lactobacillus johnsonii MG (MG) isolated from mice with interaction with tight junction on gut barrier function with Caco-2 cell model. Pretreatment with MG enhanced barrier function and showed protective effect against Enterococcus faecium provided damage. MG treatment increased the gene expressions of transcriptional regulator NFKB and major tight junction protein, ZO-1.

New Flow Cytometric Methods for Monitoring STAT5 Signaling Reveal Responses to SARS-CoV-2 Antigen-Specific Stimulation in FOXP3+ Regulatory T Cells also in Patients with Advanced Chronic Lymphocytic Leukemia

Increased frequency of CD4⁺CD25⁺ regulatory T-cells (Treg) has been associated with disease progression in chronic lymphocytic leukemia (CLL). Flow cytometric methods, which allow for the simultaneous analysis of their specific transcription factor Foxp3 and activated STAT proteins, together with proliferation can help to elucidate the signaling mechanisms driving Treg expansion and suppression of FOXP3- conventional CD4⁺T-cells (Tcon). Herein, we first report a novel approach in which STAT5 phosphorylation (pSTAT5) and proliferation (BrdU-FITC incorporation) could be analyzed specifically in FOXP3+ and FOXP3- responding cells after CD3/CD28 stimulation. The addition of magnetically purified CD4⁺CD25⁺ T-cells from healthy donors to cocultured autologous CD4⁺CD25^- T-cells resulted in suppression of Tcon cell cycle progression accompanied by a decrease in pSTAT5. Next, a method using imaging flow cytometry is presented for the detection of cytokine-dependent pSTAT5 nuclear translocation in FOXP3-expressing cells. Finally, we discuss our experimental data obtained by combining Treg pSTAT5 analysis and antigen-specific stimulation with SARS-CoV-2 antigens. Applying these methods on samples from patients revealed Treg responses to antigen-specific stimulation and significantly higher basal pSTAT5 in CLL patients treated with immunochemotherapy. Thus, we speculate that through the use of this pharmacodynamic tool, the efficacy of immunosuppressive drugs and their possible off-target effects can be assessed.

Characterization of exosomes derived from IPEC-J2 treated with probiotic Bacillus amyloliquefaciens SC06 and its regulation of macrophage functions

Probiotics can maintain or improve health by modulating the response of immune cells in the gastrointestinal tract. However, the mechanisms by which probiotics promote macrophage (Mφ) activity are poorly understood. Here, we evaluated exosomes derived from intestinal epithelial cells treated with Bacillus amyloliquefaciens SC06 (Ba) and investigated the regulation of Mφ phagocytosis, apoptosis, and polarization. We isolated two exosomes from intestinal porcine epithelial cell lines (IPEC-J2) with or without Ba-treatment, named Ba-Exo and Exo, respectively. They had typical sizes and a cup-shaped morphology, and their surfaces presented typical exosomes-associated proteins, including CD63, ALIX, and TSG101. Ba-Exo and Exo could entrer Mφ (3D4/21 cells) effectively. Moreover, an in vitro phagocytosis assay demonstrated that Ba-Exo can promote phagocytosis of Mφ. Similar to Exo, Ba-Exo had no effect on Mφ apoptosis. Furthermore, Ba-Exo significantly increased inducible nitric oxide synthase (iNOS), declined the expression of arginase 1 (Arg1) in Mφ, and stimulated Mφ polarization to M1. To explore the differences in the regulation of Mφ polarization between Ba-Exo and Exo, we performed reverse transcription quantitative polymerase chain reaction analysis of the small RNAs and found that miR-222 increased in the Ba-Exo group compared to that in the Exo group. These results provide a new perspective on the relationship between probiotics and intestinal immunity.

Effect of the Microbiome on Intestinal Innate Immune Development in Early Life and the Potential Strategy of Early Intervention

Early life is a vital period for mammals to be colonized with the microbiome, which profoundly influences the development of the intestinal immune function. For neonates to resist pathogen infection and avoid gastrointestinal illness, the intestinal innate immune system is critical. Thus, this review summarizes the development of the intestinal microbiome and the intestinal innate immune barrier, including the intestinal epithelium and immune cells from the fetal to the weaning period. Moreover, the impact of the intestinal microbiome on innate immune development and the two main way of early-life intervention including probiotics and fecal microbiota transplantation (FMT) also are discussed in this review. We hope to highlight the crosstalk between early microbial colonization and intestinal innate immunity development and offer some information for early intervention.

Multiorgan microphysiological systems as tools to interrogate interorgan crosstalk and complex diseases

Metabolic and inflammatory disorders such as autoimmune and neurodegenerative diseases are increasing at alarming rates. Many of these are not tissue-specific occurrences but complex, systemic pathologies of unknown origin for which no cure exists. Such complexity obscures causal relationships among factors regulating disease progression. Emerging technologies mimicking human physiology, such as microphysiological systems (MPSs), offer new possibilities to provide clarity in systemic metabolic and inflammatory diseases. Controlled interaction of multiple MPSs and the scalability of biological complexity in MPSs, supported by continuous multiomic monitoring, might hold the key to identifying novel relationships between interorgan crosstalk, metabolism, and immunity. In this perspective, I aim to discuss the current state of modeling multiorgan physiology and evaluate current opportunities and challenges.

Progressive use of multispectral imaging flow cytometry in various research areas

Multi-spectral imaging flow cytometry (MIFC) has become one of the most powerful technologies for investigating general analytics, molecular and cell biology, biotechnology, medicine, and related fields. It combines the capabilities of the morphometric and photometric analysis of single cells and micrometer-sized particles in flux with regard to thousands of events. It has become the tool of choice for a wide range of research and clinical applications. By combining the features of flow cytometry and fluorescence microscopy, it offers researchers the ability to couple the spatial resolution of multicolour images of cells and organelles with the simultaneous analysis of a large number of events in a single system. This provides the opportunity to visually confirm findings and collect novel data that would otherwise be more difficult to obtain. This has led many researchers to design innovative assays to gain new insight into important research questions. To date, it has been successfully used to study cell morphology, surface and nuclear protein co-localization, protein-protein interactions, cell signaling, cell cycle, cell death, and cytotoxicity, intracellular calcium, drug uptake, pathogen internalization, and other applications. Herein we describe some of the recent advances in the field of multiparametric imaging flow cytometry methods in various research areas.

Coculture of primary human colon monolayer with human gut bacteria

The presence of microbes in the colon impacts host physiology. Therefore, microbes are being evaluated as potential treatments for colorectal diseases. Humanized model systems that enable robust culture of primary human intestinal cells with bacteria facilitate evaluation of potential treatments. Here, we describe a protocol that can be used to coculture a primary human colon monolayer with aerotolerant bacteria. Primary human colon cells maintained as organoids are dispersed into single-cell suspensions and then seeded on collagen-coated Transwell inserts, where they attach and proliferate to form confluent monolayers within days of seeding. The confluent monolayers are differentiated for an additional 4 d and then cocultured with bacteria. As an example application, we describe how to coculture differentiated colon cells for 8 h with four strains of Bacteroides thetaiotaomicron, each engineered to detect different colonic microenvironments via genetically embedded logic circuits incorporating deoxycholic acid and anhydrotetracycline sensors. Characterization of this coculture system reveals that barrier function remains intact in the presence of engineered B. thetaiotaomicron. The bacteria stay close to the mucus layer and respond in a microenvironment-specific manner to the inducers (deoxycholic acid and anhydrotetracycline) of the genetic circuits. This protocol thus provides a useful mucosal barrier system to assess the effects of bacterial cells that respond to the colonic microenvironment, and may also be useful in other contexts to model human intestinal barrier properties and microbiota-host interactions.

Probiotics: a Promising Generation of Heavy Metal Detoxification

Different environmental toxins especially heavy metals exist in soil, water, and air recording toxic effect on human, animal, and plant. These toxicant elements are widespread in environment causing various disturbances in biological systems. Numerous strategies have been applied recently to alleviate heavy metal contamination; however, most of these strategies were costly and seemed unfriendly to our environment. Probiotics are living cell bacteria with beneficial characteristics for human health. Lactobacillus and Bifidobacterium are the major probiotic groups; however, Pediococcus, Lactococcus, Bacillus, and yeasts are recorded as probiotic. The vital role of the probiotics on maintenance of body health was previously investigated. Probiotics were previously recorded to its powerful capacity to bind numerous targets and eliminate them with feces. These targets may be aluminum, cadmium, lead, or arsenic. The current review discusses the history of probiotics, detoxification role of probiotics caused by heavy metals, and mechanism of their action that modulate different signaling pathway disturbance associated with heavy metal accumulation in biological system.

Isolation, characterisation and phagocytic function of human macrophages from human peripheral blood

Macrophages are among the most important cells of the immune system. Among other functions, they take part in almost all defense actions against foreign bodies and bacteria, being particularly important in infections, wound healing, and foreign body reactions. Considering their importance for the health of the human body, as well as their important role in several diseases, the in vitro studies based on these cells, are a crucial research field. Taking all mentioned into account, this study describes a simple isolation method of human macrophages (MFUM-HMP-001 and MFUM-HMP-002 cell lines) from peripheral blood. For this purpose, the morphology, the viability, and the phagocytotic activity of the isolated cells were tested. The Immunostaining of MFUM-HMP-001 and MFUM-HMP-002 cells confirmed the macrophage cell markers CD68, CD80, and CD163/M130. The phagocytotic activity was marked in both MFUM-HMP-001 and MFUM-HMP-002 cells, as was the phagocytosis of the pHrodo green Escherichia coli bioparticles conjugates, which was enhanced with the addition of lipopolysaccharide. The cells were stable and exhibited good growth. According to our results, both cell lines are useful for the development of novel macrophage cell-based in vitro models.

Advanced In Vitro Testing Strategies and Models of the Intestine for Nanosafety Research

There is growing concern about the potential adverse effects of oral exposure to engineered nanomaterials (ENM). Recent years have witnessed major developments in and advancement of intestinal in vitro models for nanosafety evaluation. The present paper reviews the key factors that should be considered for inclusion in nonanimal alternative testing approaches to reliably reflect the in vivo dynamics of the physicochemical properties of ENM as well the intestinal physiology and morphology. Currently available models range from simple cell line-based monocultures to advanced 3D systems and organoids. In addition, in vitro approaches exist to replicate the mucous barrier, digestive processes, luminal flow, peristalsis, and interactions of ENM with the intestinal microbiota. However, while the inclusion of a multitude of individual factors/components of particle (pre)treatment, exposure approach, and cell model approximates in vivo-like conditions, such increasing complexity inevitably affects the system's robustness and reproducibility. The selection of the individual modules to build the in vitro testing strategy should be driven and justified by the specific purpose of the study and, not least, the intended or actual application of the investigated ENM. Studies that address health hazards of ingested ENM likely require different approaches than research efforts to unravel the fundamental interactions or toxicity mechanisms of ENM in the intestine. Advanced reliable and robust in vitro models of the intestine, especially when combined in an integrated testing approach, offer great potential to further improve the field of nanosafety research.

The Lipocalin2 Gene is Regulated in Mammary Epithelial Cells by NFκB and C/EBP In Response to Mycoplasma

Lcn2 gene expression increases in response to cell stress signals, particularly in cells involved in the innate immune response. Human Lcn2 (NGAL) is increased in the blood and tissues in response to many stressors including microbial infection and in response to LPS in myeloid and epithelial cells. Here we extend the microbial activators of Lcn2 to mycoplasma and describe studies in which the mechanism of Lcn2 gene regulation by MALP-2 and mycoplasma infection was investigated in mouse mammary epithelial cells. As for the LPS response of myeloid cells, Lcn2 expression in epithelial cells is preceded by increased TNFα, IL-6 and IκBζ expression and selective reduction of IκBζ reduces Lcn2 promoter activity. Lcn2 promoter activation remains elevated well beyond the period of exposure to MALP-2 and is persistently elevated in mycoplasma infected cells. Activation of either the human or the mouse Lcn2 promoter requires both NFκB and C/EBP for activation. Thus, Lcn2 is strongly and enduringly activated by mycoplasma components that stimulate the innate immune response with the same basic regulatory mechanism for the human and mouse genes.

Effect of Lactobacillus spp. on adhesion, invasion, and translocation of Campylobacter jejuni in chicken and pig small-intestinal epithelial cell lines

BACKGROUND

Campylobacter spp. are a major cause of bacterial food-borne diarrhoeal disease. This mainly arises through contamination of meat products during processing. For infection, Campylobacter spp. must adhere to epithelial cells of the mucus layer, survive conditions of the gastrointestinal tract, and colonise the intestine of the host. Addition of probiotic bacteria might promote competitive adhesion to epithelial cells, consequently reducing Campylobacter jejuni colonisation. Effect of Lactobacillus spp. (PCS20, PCS22, PCS25, LGG, PCK9) on C. jejuni adhesion, invasion and translocation in pig (PSI cl.1) and chicken (B1OXI) small-intestine cell lines, as well as pig enterocytes (CLAB) was investigated.

RESULTS

Overall, in competitive adhesion assays with PSI cl.1 and CLAB cell monolayers, the addition of Lactobacillus spp. reduced C. jejuni adherence to the cell surface, and negatively affected the C. jejuni invasion. Interestingly, Lactobacillus spp. significantly impaired C. jejuni adhesion in three-dimensional functional PSI cl.1 and B1OXI cell models. Also, C. jejuni did not translocate across PSI cl.1 and B1OXI cell monolayers when co-incubated with probiotics. Among selected probiotics, Lactobacillus rhamnosus LGG was the strain that reduced adhesion efficacy of C. jejuni most significantly under co-culture conditions.

CONCLUSION

The addition of Lactobacillus spp. to feed additives in livestock nutrition might be an effective novel strategy that targets Campylobacter adhesion to epithelial cells, and thus prevents colonisation, reduces the transmission, and finally lowers the incidence of human campylobacteriosis.

Probiotic mediated NF-κB regulation for prospective management of type 2 diabetes

Diabetes and other lifestyle disorders have been recognized as the leading cause of morbidity and mortality globally. Nuclear factor kappa B (NF-κB) is a major factor involved in the early pathobiology of diabetes and studies reveal that hyperglycemic conditions in body leads to NF-κB mediated activation of several cytokines, chemokines and inflammatory molecules. NF-κB family comprises of certain DNA-binding protein factors that elicit the transcription of pro-inflammatory molecules. Various studies have identified NF-κB as a promising target for diabetic management. Probiotics have been proposed as bio-therapeutic agents for treatment of inflammatory disorders and many other chronic clinical stages. The precise mechanisms by which probiotics acts is yet to be fully understood, however research findings have indicated their role in NF-κB modulation. The current review highlights NF-κB as a bio-therapeutic target for probable management of type 2 diabetes through probiotic intervention.

Adhesion mechanisms mediated by probiotics and prebiotics and their potential impact on human health

Adhesion ability to the host is a classical selection criterion for potential probiotic bacteria that could result in a transient colonisation that would help to promote immunomodulatory effects, as well as stimulate gut barrier and metabolic functions. In addition, probiotic bacteria have a potential protective role against enteropathogens through different mechanisms including production of antimicrobial compounds, reduction of pathogenic bacterial adhesion and competition for host cell binding sites. The competitive exclusion by probiotic bacteria has a beneficial effect not only on the gut but also in the urogenital tract and oral cavity. On the other hand, prebiotics may also act as barriers to pathogens and toxins by preventing their adhesion to epithelial receptors. In vitro studies with different intestinal cell lines have been widely used along the last decades to assess the adherence ability of probiotic bacteria and pathogen antagonism. However, extrapolation of these results to in vivo conditions still remains unclear, leading to the need of optimisation of more complex in vitro approaches that include interaction with the resident microbiota to address the current limitations. The aim of this mini review is to provide a comprehensive overview on the potential effect of the adhesive properties of probiotics and prebiotics on the host by focusing on the most recent findings related with adhesion and immunomodulatory and antipathogenic effect on human health.

Intestinal in vitro and ex vivo Models to Study Host-Microbiome Interactions and Acute Stressors

The gut microbiome is extremely important for maintaining homeostasis with host intestinal epithelial, neuronal, and immune cells and this host-microbe interaction is critical during times of stress or disease. Environmental, nutritional, and cognitive stress are just a few factors known to influence the gut microbiota and are thought to induce microbial dysbiosis. Research on this bidirectional relationship as it pertains to health and disease is extensive and rapidly expanding in both in vivo and in vitro/ex vivo models. However, far less work has been devoted to studying effects of host-microbe interactions on acute stressors and performance, the underlying mechanisms, and the modulatory effects of different stressors on both the host and the microbiome. Additionally, the use of in vitro/ex vivo models to study the gut microbiome and human performance has not been researched extensively nor reviewed. Therefore, this review aims to examine current evidence concerning the current status of in vitro and ex vivo host models, the impact of acute stressors on gut physiology/microbiota as well as potential impacts on human performance and how we can parlay this information for DoD relevance as well as the broader scientific community. Models reviewed include widely utilized intestinal cell models from human and animal models that have been applied in the past for stress or microbiology research as well as ex vivo organ/tissue culture models and new innovative models including organ-on-a-chip and co-culture models.

A guide to polarized airway epithelial models for studies of host-pathogen interactions

Mammalian lungs are organs exhibiting the cellular and spatial complexity required for gas exchange to support life. The respiratory epithelium internally lining the airways is susceptible to infections due to constant exposure to inhaled microbes. Biomedical research into respiratory bacterial infections in humans has been mostly carried out using small mammalian animal models or two-dimensional, submerged cultures of undifferentiated epithelial cells. These experimental model systems have considerable limitations due to host specificity of bacterial pathogens and lack of cellular and morphological complexity. This review describes the in vitro differentiated and polarized airway epithelial cells of human origin that are used as a model to study respiratory bacterial infections. Overall, these models recapitulate key aspects of the complexity observed in vivo and can help in elucidating the molecular details of disease processes observed during respiratory bacterial infections.

Comparison of conventional and advanced in vitro models in the toxicity testing of nanoparticles

Humans are exposed to a wide variety of nanoparticles (NPs) present in the environment, in consumer, health and medical products, and in food. Conventional cytotoxicity testing compared to animal testing is less expensive, faster and avoids ethical problems at the expense of a lower predictive value. New cellular models and exposure conditions have been developed to overcome the limitations of conventional cell culture and obtain more predictive data. The use of three-dimensional culture, co-culture and inclusion of mechanical stimulation can provide physiologically more relevant culture conditions. These systems are particularly relevant for oral, respiratory and intravenous exposure to NPs and it may be assumed that physiologically relevant application of the NPs can improve the predictive value of in vitro testing. Various groups have used advanced culture and exposure systems, but few direct comparisons between data from conventional cultures and from advanced systems exist. In silico models may present another option to predict human health risk by NPs without using animal studies. In the absence of validation, the question whether these alternative models provide more predictive data than conventional testing remains elusive.

Nonsteroidal Anti-Inflammatory Drug-Induced Leaky Gut Modeled Using Polarized Monolayers of Primary Human Intestinal Epithelial Cells

The intestinal epithelium provides a critical barrier that separates the gut microbiota from host tissues. Nonsteroidal anti-inflammatory drugs (NSAIDs) are efficacious analgesics and antipyretics and are among the most frequently used drugs worldwide. In addition to gastric damage, NSAIDs are toxic to the intestinal epithelium, causing erosions, perforations, and longitudinal ulcers in the gut. Here, we use a unique in vitro human primary small intestinal cell monolayer system to pinpoint the intestinal consequences of NSAID treatment. We found that physiologically relevant doses of the NSAID diclofenac (DCF) are cytotoxic because they uncouple mitochondrial oxidative phosphorylation and generate reactive oxygen species. We also find that DCF induces intestinal barrier permeability, facilitating the translocation of compounds from the luminal to the basolateral side of the intestinal epithelium. The results we outline here establish the utility of this novel platform, representative of the human small intestinal epithelium, to understand NSAID toxicity, which can be applied to study multiple aspects of gut barrier function including defense against infectious pathogens and host-microbiota interactions.

Cytokine production in vitro and in rat model of colitis in response to Lactobacillus plantarum LS/07

Over the past decade, it has become clear that specific probiotic lactobacilli are valuable in the prevention and treatment of infectious and inflammatory diseases of gastrointestinal tract but their successful application would benefit greatly from a better understanding of the mechanisms of individual strains. Hence, each probiotic strain should be characterized for their immune activity before being proposed for clinical applications. The aim of the study was to characterize the immunomodulatory activity of the strain Lactobacillus (L.) plantarum LS/07 in vitro using functional gut model and to study its anti-inflammatory potential in dextran sulphate sodium (DSS)-induced colitis in rats. We showed that L. plantarum LS/07 induced production of IL-10 in macrophages derived from blood monocytes as well as monocyte/macrophages cell line stimulated indirectly via enterocytes in vitro. In rat model of colitis, L. plantarum LS/07 attenuated the DSS-induced signs of inflammatory process in colon such as weight loss, diarrhoea, infiltration of inflammatory cells associated with decreased colon weight/length ratio, inhibited gut mucosa destruction and depletion of goblet cells. Moreover, the strain increased the concentration of anti-inflammatory cytokine IL-10 in mucosal tissue. In conclusion, the protective effects of L. plantarum LS/07 in the DSS-induced colitis model seem to be related to the stimulation of IL-10 and the restoration of goblet cells and indicate it as a good candidate to prevent and treat diseases associated with inflammation.

Early Postnatal Diets Affect the Bioregional Small Intestine Microbiome and Ileal Metabolome in Neonatal Pigs

Background: Breastfeeding is known to be protective against gastrointestinal disorders and may modify gut development. Although the gut microbiome has been implicated, little is known about how early diet affects the small intestine microbiome.Objective: We hypothesized that disparate early diets would promote unique microbial profiles in the small intestines of neonatal pigs.Methods: Male and female 2-d-old White Dutch Landrace pigs were either sow fed or provided dairy (Similac Advance powder; Ross Products Abbott Laboratories) or soy (Enfamil Prosobee Lipil powder; Mead Johnson Nutritionals) infant formulas until day 21. Bacterial ecology was assessed in the contents of the small intestine through the use of 16S ribosomal RNA sequencing. α-Diversity, β-diversity, and differential abundances of operational taxonomic units were assessed by ANOVA, permutational ANOVA, and negative binomial regression, respectively. Ileum tissue metabolomics were measured by LC-mass spectrometry and assessed by weighted correlation network analysis.Results: Greater α-diversity was observed in the duodena of sow-fed compared with formula-fed neonatal pigs (P < 0.05). No differences were observed in the ilea. Firmicutes represented the most abundant phylum across all diets in duodena (78.8%, 80.1%, and 53.4% relative abundance in sow, dairy, and soy groups, respectively), followed by Proteobacteria in sow (12.2%) and dairy (12.4%) groups and Cyanobacteria in soy-fed (36.2%) pigs. In contrast to those in the duodenum, Proteobacteria was the dominant phylum in the ileum, with >60% relative abundance in all of the groups. In the duodenum, 77 genera were altered by diet, followed by 48 in the jejunum and 19 in the ileum. Metabolomics analyses revealed associations between ileum tissue metabolites (e.g., acylcarnitines, 3-aminoisobutyric acid) and diet-responsive microbial genera.Conclusions: These results indicate that the neonatal diet has regional effects on the small intestine microbiome in pigs, with the most pronounced effects occurring in the duodena. Regional effects may be important factors when considering gut tissue metabolism and development in the postnatal period.

The microbiota and autoimmunity: Their role in thyroid autoimmune diseases

Since the 1970s, the role of infectious diseases in the pathogenesis of Graves' disease (GD) has been an object of intensive research. The last decade has witnessed many studies on Yersinia enterocolitica, Helicobacter pylori and other bacterial organisms and their potential impact on GD. Retrospective, prospective and molecular binding studies have been performed with contrary outcomes. Until now it is not clear whether bacterial infections can trigger autoimmune thyroid disease. Common risk factors for GD (gender, smoking, stress, and pregnancy) reveal profound changes in the bacterial communities of the gut compared to that of healthy controls but a pathogenetic link between GD and dysbiosis has not yet been fully elucidated. Conventional bacterial culture, in vitro models, next generation and high-throughput DNA sequencing are applicable methods to assess the impact of bacteria in disease onset and development. Further studies on the involvement of bacteria in GD are needed and may contribute to the understanding of pathogenetic processes. This review will examine available evidence on the subject.

A primary human macrophage-enteroid co-culture model to investigate mucosal gut physiology and host-pathogen interactions

Integration of the intestinal epithelium and the mucosal immune system is critical for gut homeostasis. The intestinal epithelium is a functional barrier that secludes luminal content, senses changes in the gut microenvironment, and releases immune regulators that signal underlying immune cells. However, interactions between epithelial and innate immune cells to maintain barrier integrity and prevent infection are complex and poorly understood. We developed and characterized a primary human macrophage-enteroid co-culture model for in-depth studies of epithelial and macrophage interactions. Human intestinal stem cell-derived enteroid monolayers co-cultured with human monocyte-derived macrophages were used to evaluate barrier function, cytokine secretion, and protein expression under basal conditions and following bacterial infection. Macrophages enhanced barrier function and maturity of enteroid monolayers as indicated by increased transepithelial electrical resistance and cell height. Communication between the epithelium and macrophages was demonstrated through morphological changes and cytokine production. Intraepithelial macrophage projections, efficient phagocytosis, and stabilized enteroid barrier function revealed a coordinated response to enterotoxigenic and enteropathogenic E. coli infections. In summary, we have established the first primary human macrophage-enteroid co-culture system, defined conditions that allow for a practical and reproducible culture model, and demonstrated its suitability to study gut physiology and host responses to enteric pathogens.

A novel technique to determine the cell type specific response within an in vitro co-culture model via multi-colour flow cytometry

Determination of the cell type specific response is essential towards understanding the cellular mechanisms associated with disease states as well as assessing cell-based targeting of effective therapeutic agents. Recently, there have been increased calls for advanced in vitro multi-cellular models that provide reliable and valuable tools correlative to in vivo. In this pursuit the ability to assess the cell type specific response is imperative. Herein, we report a novel approach towards resolving each specific cell type of a multi-cellular model representing the human lung epithelial tissue barrier via multi-colour flow cytometry (FACS). We proved via ≤ five-colour FACS that the manipulation of this in vitro model allowed each cell type to be resolved with no impact upon cell viability. Subsequently, four-colour FACS verified the ability to determine the biochemical effect (e.g. oxidative stress) of each specific cell type. This technique will be vital in gaining information upon cellular mechanics when using next-level, multi-cellular in vitro strategies.

Single-cell analysis reveals IGF-1 potentiation of inhibition of the TGF-β/Smad pathway of fibrosis in human keratocytes in vitro

Corneal wound healing is often affected by TGF-β–mediated fibrosis and scar formation. Guided fibrosis with IGF-1 and antifibrotic substances might maintain corneal transparency. Primary human corneal keratocytes under serum-free conditions were used as a model of corneal stromal wounding, with markers of corneal fibrosis and opacity studied under TGF-β2 stimulation. Single-cell imaging flow cytometry was used to determine nuclearization of Smad3, and intracellular fluorescence intensity of Smad7 and the corneal crystallin aldehyde dehydrogenase 3A1. Extracellular matrix proteoglycans keratocan and biglycan were quantified using ELISAs. On the TGF-β2 background, the keratocytes were treated with IGF-1, and suberoylanilidehydroxamic acid (SAHA) or halofuginone ± IGF-1. IGF-1 alone decreased Smad3 nuclearization and increased aldehyde dehydrogenase 3A1 expression, with favorable extracellular matrix proteoglycan composition. SAHA induced higher Smad7 levels and inhibited translocation of Smad3 to the nucleus, also when combined with IGF-1. Immunofluorescence showed that myofibroblast transdifferentiation is attenuated and appearance of fibroblasts is favored by IGF-1 alone and in combination with the antifibrotic substances. The TGF-β/Smad pathway of fibrosis and opacity was inhibited by IGF-1, and further with SAHA in particular, and with halofuginone. IGF-1 is thus a valid aid to antifibrotic treatment, with potential for effective and transparent corneal wound healing.

Oral Administration of Probiotics Inhibits Absorption of the Heavy Metal Cadmium by Protecting the Intestinal Barrier

The heavy metal cadmium (Cd) is an environmental pollutant that causes adverse health effects in humans and animals. Our previous work demonstrated that oral administration of probiotics can significantly inhibit Cd absorption in the intestines of mice, but further evidence is needed to gain insights into the related protection mode. The goal of this study was to evaluate whether probiotics can inhibit Cd absorption through routes other than the Cd binding, with a focus on gut barrier protection. In the in vitro assay, both the intervention and therapy treatments of Lactobacillus plantarum CCFM8610 alleviated Cd-induced cytotoxicity in the human intestinal cell line HT-29 and protected the disruption of tight junctions in the cell monolayers. In a mouse model, probiotics with either good Cd-binding or antioxidative ability increased fecal Cd levels and decreased Cd accumulation in the tissue of Cd-exposed mice. Compared with the Cd-only group, cotreatment with probiotics also reversed the disruption of tight junctions, alleviated inflammation, and decreased the intestinal permeability of mice. L. plantarum CCFM8610, a strain with both good Cd binding and antioxidative abilities, exhibited significantly better protection than the other two strains. These results suggest that along with initial intestinal Cd sequestration, probiotics can inhibit Cd absorption by protecting the intestinal barrier, and the protection is related to the alleviation of Cd-induced oxidative stress. A probiotic with both good Cd-binding and antioxidative capacities can be used as a daily supplement for the prevention of oral Cd exposure.

IMPORTANCE

The heavy metal cadmium (Cd) is an environmental pollutant that causes adverse health effects in humans and animals. For the general population, food and drinking water are the main sources of Cd exposure due to the biomagnification of Cd within the food chain; therefore, the intestinal tract is the first organ that is susceptible to Cd contamination. Moreover, Cd exposure causes the disruption of the intestinal barrier and further induces the amplification of Cd absorption. The present study confirms that, along with initial intestinal Cd sequestration, oral administration of probiotics can inhibit Cd absorption by protecting the intestinal barrier. A probiotic with both good Cd-binding and antioxidative capacities can be used as a daily supplement for the prevention of oral Cd exposure.

Age-Related Differences in Percentages of Regulatory and Effector T Lymphocytes and Their Subsets in Healthy Individuals and Characteristic STAT1/STAT5 Signalling Response in Helper T Lymphocytes

The dynamic process of the development of the immune system can in itself result in age-related immune malfunctions. In this study, we analysed lymphocyte subsets in the peripheral blood of 60 healthy donors, divided into groups of children, adolescents, and adults, focusing on effector (Teff) and regulatory (Treg) T lymphocytes and STAT1/STAT5 signalling response in helper T lymphocytes (Th) in adults, using flow cytometry. Our results demonstrate a decrease in the percentage of total Tregs and an increase in the percentage of total Teffs with age and a consequential immense increase in the Teff/Treg ratio. The increase of Teffs was most apparent in Th1, Th1Th17, and Th17CD161- subsets. Significant Th lymphocyte STAT1 expression differences were observed between children and adolescents, which were associated with the decrease in activated Tregs. Higher expression of STAT1 was found in FoxP3hi than in FoxP3low Th lymphocytes, while significant IL-2 induced STAT5 phosphorylation differences were found among the subsets of Th lymphocytes in adults. Our study demonstrates age-related changes in circulating Teff and Treg, as well as significant differences in STAT5/STAT1 signalling among FoxP3+ Th lymphocytes, providing new advances in the understanding of immunosenescence.

Modulation of the spleen transcriptome in domestic turkey (Meleagris gallopavo) in response to aflatoxin B1 and probiotics

Poultry are highly susceptible to the immunotoxic effects of the food-borne mycotoxin aflatoxin B1 (AFB1). Exposure impairs cell-mediated and humoral immunity, limits vaccine efficacy, and increases the incidence of costly secondary infections. We investigated the molecular mechanisms of AFB1 immunotoxicity and the ability of a Lactobacillus-based probiotic to protect against aflatoxicosis in the domestic turkey (Meleagris gallopavo). The spleen transcriptome was examined by RNA sequencing (RNA-seq) of 12 individuals representing four treatment groups. Sequences (6.9 Gb) were de novo assembled to produce over 270,000 predicted transcripts and transcript fragments. Differential expression analysis identified 982 transcripts with statistical significance in at least one comparison between treatment groups. Transcripts with known immune functions comprised 27.6 % of significant expression changes in the AFB1-exposed group. Short exposure to AFB1 suppressed innate immune transcripts, especially from antimicrobial genes, but increased the expression of transcripts from E3 ubiquitin-protein ligase CBL-B and multiple interleukin-2 response genes. Up-regulation of transcripts from lymphotactin, granzyme A, and perforin 1 could indicate either increased cytotoxic potential or activation-induced cell death in the spleen during aflatoxicosis. Supplementation with probiotics was found to ameliorate AFB1-induced expression changes for multiple transcripts from antimicrobial and IL-2-response genes. However, probiotics had an overall suppressive effect on immune-related transcripts.

Non-alcoholic fatty liver disease, diet and gut microbiota

Non-alcoholic fatty liver disease (NAFLD) is a severe liver disease that is increasing in prevalence with the worldwide epidemic of obesity and its related insulin-resistance state. Evidence for the role of the gut microbiota in energy storage and the subsequent development of obesity and some of its related diseases is now well established. More recently, a new role of gut microbiota has emerged in NAFLD. The gut microbiota is involved in gut permeability, low-grade inflammation and immune balance, it modulates dietary choline metabolism, regulates bile acid metabolism and produces endogenous ethanol. All of these factors are molecular mechanisms by which the microbiota can induce NAFLD or its progression toward overt non-alcoholic steatohepatitis. Modification of the gut microbiota composition and/or its biochemical capacity by specific dietary or pharmacological interventions may advantageously affect host metabolism. Large-scale intervention trials, investigating the potential benefit of prebiotics and probiotics in improving cardiometabolic health in high-risk populations, are fervently awaited.