Intestinal epithelial cells: at the interface of the microbiota and mucosal immunity

Long-term disinfectant exposure on intestinal immunity and microbiome variation of grass carp

The gut microbiome is crucial in maintaining fish health homeostasis. Disinfectants can kill important pathogens and disinfect fish eggs, yet their effect on the immune pathways and intestinal microbiome in healthy fish remains unknown. In this study, we investigated the effects of two disinfectants on the transcriptome profiles, immunological response, and gut microbiota dynamics of grass carp over a four-week trial. In particular, aquatic water was disinfected with 80 μg/L glutaraldehyde or 50 μg/L povidone-iodine. We found that glutaraldehyde and povidone-iodine induced gut antioxidant system and depressed the function of grass carp digestive enzymes. The results of the 16S rDNA high-throughput sequencing identified a reduction in the diversity of grass carp gut microbiota following the disinfectant treatment. Moreover, transcriptome profiling revealed that disinfectant exposure altered the immune-related pathways of grass carp and inhibited the expression of inflammation and tight junction related genes. Finally, the histopathological observation and apoptosis detection results suggested that the long-term diet of disinfectant destroyed intestinal structural integrity and promoted apoptosis. In conclusion, long-term exposure to disinfectants was observed to reduce oxidation resistance, suppress the immune response, dysbiosis of the intestinal flora, and resulted in increasing the apoptosis in intestinal of grass carp.

Activation of angiogenin expression in macrophages by lipopolysaccharide via the TLR4/NF-κB pathway in colitis

Inflammatory bowel disease (IBD) is a debilitating condition that can lead to life-threatening complications. Macrophages are crucial in IBD management because they secrete various cytokines and regulate tissue repair. Macrophage-derived angiogenin (ANG) has been shown to be essential for limiting colonic inflammation, but its upstream regulatory pathway and role in macrophages remain unclear. Here we show that ANG expression is up-regulated in macrophages during colitis treatment or upon lipopolysaccharides (LPS) treatment. Mechanistically, LPS activates Toll-like receptor 4 (TLR4) to initiate NF-κB translocation from the cytoplasm to the nucleus, where it binds to the ANG promoter and enhances its transcriptional activity, leading to increased ANG expression. Interestingly, our data also reveal that the deletion of ANG in macrophages has no adverse effect on key macrophage functions, such as phagocytosis, chemotaxis, and cell survival. Our findings establish a "LPS-TLR4-NF-κB-ANG" regulatory axis in inflammatory disorders and confirm that ANG controls inflammation in a paracrine manner, highlighting the importance of ANG as a key mediator in the complex network of inflammatory processes.

Unveiling the intratumoral microbiota within cancer landscapes

Recent advances in cancer research have unveiled a significant yet previously underappreciated aspect of oncology: the presence and role of intratumoral microbiota. These microbial residents, encompassing bacteria, fungi, and viruses within tumor tissues, have been found to exert considerable influence on tumor development, progression, and the efficacy of therapeutic interventions. This review aims to synthesize these groundbreaking discoveries, providing an integrated overview of the identification, characterization, and functional roles of intratumoral microbiota in cancer biology. We focus on elucidating the complex interactions between these microorganisms and the tumor microenvironment, highlighting their potential as novel biomarkers and therapeutic targets. The purpose of this review is to offer a comprehensive understanding of the microbial dimension in cancer, paving the way for innovative approaches in cancer diagnosis and treatment.

The silent threat: Nanopolystyrene and chrysene pollutants disrupt the intestinal mucosal barrier, new insights from juvenile Siniperca chuatsi

The intestinal mucosal barrier-comprising microbial, mechanical, chemical, and immunological barriers-is critical to protection against pathogens and maintenance of host health; however, it remains unclear whether it is affected by environmental contaminants. Therefore, the present study assessed whether exposure to ambient concentrations of nanopolystyrene (NP) and chrysene (CHR)-two ubiquitous environmental pollutants in the aquatic environment-affect the intestinal mucosal barrier in juvenile Siniperca chuatsi. After exposure for 21 days, S. chuatsi exhibited intestinal oxidative stress and imbalance of intestinal microbial homeostasis. NP and/or CHR exposure also disrupted the intestinal mechanical barrier, as evidenced by the altered intestinal epithelial cell morphology, disrupted structure of intercellular tight junctions, and decreased expression of tight junction proteins. Damage to the intestinal chemical barrier manifested as thinning of the mucus layer owing to the loss and damage of goblet cells. Furthermore, the intestinal immunological barrier was impaired as indicated by the loss of intestinal intraepithelial lymphocytes and increase in pro-inflammatory cytokines, chemokines, and immunoglobulins. These findings collectively suggest that the intestinal mucosal barrier was damaged. This study is, to the best of our knowledge, the first to report that exposure to NP and/or CHR at environmentally relevant concentrations disrupts the intestinal mucosal barrier in organisms and highlight the significance of nanoplastic/CHR pollution for intestinal health.

Gut microbiota as a key regulator of intestinal mucosal immunity

Gut microbiota is a complex microbial community with the ability of maintaining intestinal health. Intestinal homeostasis largely depends on the mucosal immune system to defense external pathogens and promote tissue repair. In recent years, growing evidence revealed the importance of gut microbiota in shaping intestinal mucosal immunity. Therefore, according to the existing findings, this review first provided an overview of intestinal mucosal immune system before summarizing the regulatory roles of gut microbiota in intestinal innate and adaptive immunity. Specifically, this review delved into the gut microbial interactions with the cells such as intestinal epithelial cells (IECs), macrophages, dendritic cells (DCs), neutrophils, and innate lymphoid cells (ILCs) in innate immunity, and T and B lymphocytes in adaptive immunity. Furthermore, this review discussed the main effects of gut microbiota dysbiosis in intestinal diseases and offered future research prospects. The review highlighted the key regulatory roles of gut microbiota in intestinal mucosal immunity via various host-microbe interactions, providing valuable references for the development of microbial therapy in intestinal diseases.

Roles of airway and intestinal epithelia in responding to pathogens and maintaining tissue homeostasis

Epithelial cells form a resilient barrier and orchestrate defensive and reparative mechanisms to maintain tissue stability. This review focuses on gut and airway epithelia, which are positioned where the body interfaces with the outside world. We review the many signaling pathways and mechanisms by which epithelial cells at the interface respond to invading pathogens to mount an innate immune response and initiate adaptive immunity and communicate with other cells, including resident microbiota, to heal damaged tissue and maintain homeostasis. We compare and contrast how airway and gut epithelial cells detect pathogens, release antimicrobial effectors, collaborate with macrophages, Tregs and epithelial stem cells to mount an immune response and orchestrate tissue repair. We also describe advanced research models for studying epithelial communication and behaviors during inflammation, tissue injury and disease.

Efficacy of Laurus nobilis L. for Tight Junction Protein Imbalance in Leaky Gut Syndrome

Laurus nobilis L. (LNL) belongs to the evergreen Lauraceae family. It is native to the Mediterranean and widely distributed in the southern United States, Europe, and the Middle East. LNL is rich in active ingredients of the sesquiterpene lactone series and has been reported to have antioxidant, anti-inflammatory, and anticancer effects. And parthenolide, known as a sesquiterpene lactone-based compound, inhibits the activation of lipopolysaccharide-binding protein (LBP), which is a major trigger for leaky gut syndrome. However, the effectiveness of LNL in improving the state of increased intestinal permeability has not yet been reported. Therefore, we demonstrated the efficacy of LNL, which is known to be rich in parthenolide, in improving intestinal permeability induced by IL-13. We investigated the improvement in permeability and analyzed major tight junction proteins (TJs), permeability-related mechanisms, weight and disease activity indices, and corresponding cytokine mechanisms. LNL maintained TJs homeostasis and clinical improvement by reducing increased claudin-2 through the inhibition of IL-13/STAT6 activation in TJ-damaged conditions. These results are expected to be effective in preventing leaky gut syndrome through the TJ balance and to further improve intestinal-related diseases, such as inflammatory bowel disease.

The Cross-talk Between Intestinal Microbiota and MDSCs Fuels Colitis-associated Cancer Development

Intestinal chronic inflammation is associated with microbial dysbiosis and accumulation of various immune cells including myeloid-derived suppressor cells (MDSC), which profoundly impact the immune microenvironment, perturb homeostasis and increase the risk to develop colitis-associated colorectal cancer (CAC). However, the specific MDSCs-dysbiotic microbiota interactions and their collective impact on CAC development remain poorly understood. In this study, using a murine model of CAC, we demonstrate that CAC-bearing mice exhibit significantly elevated levels of highly immunosuppressive MDSCs, accompanied by microbiota alterations. Both MDSCs and bacteria that infiltrate the colon tissue and developing tumors can be found in close proximity, suggesting intricate MDSC-microbiota cross-talk within the tumor microenvironment. To investigate this phenomenon, we employed antibiotic treatment to disrupt MDSC-microbiota interactions. This intervention yielded a remarkable reduction in intestinal inflammation, decreased MDSC levels, and alleviated immunosuppression, all of which were associated with a significant reduction in tumor burden. Furthermore, we underscore the causative role of dysbiotic microbiota in the predisposition toward tumor development, highlighting their potential as biomarkers for predicting tumor load. We shed light on the intimate MDSCs-microbiota cross-talk, revealing how bacteria enhance MDSC suppressive features and activities, inhibit their differentiation into mature beneficial myeloid cells, and redirect some toward M2 macrophage phenotype. Collectively, this study uncovers the role of MDSC-bacteria cross-talk in impairing immune responses and promoting tumor growth, providing new insights into potential therapeutic strategies for CAC.

SIGNIFICANCE

MDSCs-dysbiotic bacteria interactions in the intestine play a crucial role in intensifying immunosuppression within the CAC microenvironment, ultimately facilitating tumor growth, highlighting potential therapeutic targets for improving the treatment outcomes of CAC.

Intestinal Fibrogenesis in Inflammatory Bowel Diseases: Exploring the Potential Role of Gut Microbiota Metabolites as Modulators

Fibrosis, sustained by the transformation of intestinal epithelial cells into fibroblasts (epithelial-to-mesenchymal transition, EMT), has been extensively studied in recent decades, with the molecular basis well-documented in various diseases, including inflammatory bowel diseases (IBDs). However, the factors influencing these pathways remain unclear. In recent years, the role of the gut microbiota in health and disease has garnered significant attention. Evidence suggests that an imbalanced or dysregulated microbiota, along with environmental and genetic factors, may contribute to the development of IBDs. Notably, microbes produce various metabolites that interact with host receptors and associated signaling pathways, influencing physiological and pathological changes. This review aims to present recent evidence highlighting the emerging role of the most studied metabolites as potential modulators of molecular pathways implicated in intestinal fibrosis and EMT in IBDs. These studies provide a deeper understanding of intestinal inflammation and fibrosis, elucidating the molecular basis of the microbiota role in IBDs, paving the way for future treatments.

Epithelial regulation of microbiota-immune cell dynamics

The mammalian gastrointestinal tract hosts a diverse community of trillions of microorganisms, collectively termed the microbiota, which play a fundamental role in regulating tissue physiology and immunity. Recent studies have sought to dissect the cellular and molecular mechanisms mediating communication between the microbiota and host immune system. Epithelial cells line the intestine and form an initial barrier separating the microbiota from underlying immune cells, and disruption of epithelial function has been associated with various conditions ranging from infection to inflammatory bowel diseases and cancer. From several studies, it is now clear that epithelial cells integrate signals from commensal microbes. Importantly, these non-hematopoietic cells also direct regulatory mechanisms that instruct the recruitment and function of microbiota-sensitive immune cells. In this review, we discuss the central role that has emerged for epithelial cells in orchestrating intestinal immunity and highlight epithelial pathways through which the microbiota can calibrate tissue-intrinsic immune responses.

Postbiotics Implication in the Microbiota-Host Intestinal Epithelial Cells Mutualism

To sustain host health and provide the microbial community with a nutrient-rich environment, the host and gut microbiota must interact with one another. These interactions between commensal bacterial and intestinal epithelial cells (IECs) serve as the first line of defense against gut microbiota in preserving intestinal homeostasis. In this microenvironment, the post-biotics and similar molecules such as p40 exert several beneficial effects through regulation of IECs. Importantly, post-biotics were discovered to be transactivators of the EGF receptor (EGFR) in IECs, inducing protective cellular responses and alleviating colitis. The transient exposure to post-biotics such as p40 during the neonatal period reprograms IECs by upregulation of a methyltransferase, Setd1β, leading to a sustained increase in TGF- β release for the expansion of regulatory T cells (Tregs) in the intestinal lamina propria and durable protection against colitis in adulthood. This crosstalk between the IECs and post-biotic secreted factors was not reviewed previously. Therefore, this review describes the role of probiotic-derived factors in the sustainability of intestinal health and improving gut homeostasis via certain signaling pathways. In the era of precision medicine and targeted therapies, more basic, preclinical, and clinical evidence is needed to clarify the efficacy of probiotics released as functional factors in maintaining intestinal health and preventing and treating disease.

The coming future: The role of the oral-microbiota-brain axis in aroma release and perception

The field of aroma release and perception during the oral process has been well studied. However, the traditional approaches have not fully explored the integration of oral biology, microbiology, and neurology to further understand aroma release and perception mechanisms. Herein, to address the existing challenges in this field, we introduce the oral-microbiota-brain axis (OMBA), an innovative framework that encapsulates the interactive relationships among saliva and the oral mucosa, the oral microbiota, and the brain in aroma release and perception. This review introduces the OMBA and highlights its role as a key interface facilitating the sensory experience of aroma. Based on a comprehensive literature survey, the specific roles of the oral mucosa, oral microbiota, saliva, and brain in the OMBA are discussed. This integrated approach reveals the importance of each component and the interconnected relationships within this axis in the overall process of aroma release and perception. Saliva and the oral mucosa play fundamental roles in aroma release and perception; the oral microbiota regulates aroma release and impacts olfactory perception; and the brain's intricate neural circuitry is central to the decoding and interpretation of aroma signals. The components of this axis are interdependent, and imbalances can disrupt aroma perception. The OMBA framework not only enhances our comprehension of aroma release and perception but also paves the way for innovative applications that could heighten sensory experiences.

SLC6A14 promotes ulcerative colitis progression by facilitating NLRP3 inflammasome-mediated pyroptosis

BACKGROUND

Ulcerative colitis (UC) is an inflammatory condition with frequent relapse and recurrence. Evidence suggests the involvement of SLC6A14 in UC pathogenesis, but the central regulator remains unknown.

AIM

To explore the role of SLC6A14 in UC-associated pyroptosis.

METHODS

Quantitative real-time polymerase chain reaction (qRT-PCR), immunoblotting, and immunohistochemical were used to assess SLC6A14 in human UC tissues. Lipopolysaccharide (LPS) was used to induce inflammation in FHC and NCM460 cells and model enteritis, and SLC6A14 levels were assessed. Pyroptosis markers were quantified using enzyme-linked immunosorbent assay, Western blotting, and qRT-PCR, and EdU incubation, CCK-8 assays and flow cytometry were used to examine proliferation and apoptosis. Mouse models of UC were used for verification.

RESULTS

SLC6A14 was increased and correlated with NLRP3 in UC tissues. LPS-induced FHC and NCM460 cells showed increased SLC6A14 levels. Reducing SLC6A14 increased cell proliferation and suppressed apoptosis. Reducing SLC6A14 decreased pyroptosis-associated proteins (ASC, IL-1β, IL-18, NLRP3). NLRP3 overexpression counteracted the effects of sh-SLC6A14 on LPS-induced FHC and NCM460 cell pyroptosis. SLC6A14 improved the mucosa in mice with dextran sulfate sodium-induced colitis.

CONCLUSION

SLC6A14 promotes UC pyroptosis by regulating NLRP3, suggesting the therapeutic potential of modulating the SLC6A14/NLRP3 axis.

Clinical predictive value of the initial neutrophils to lymphocytes and platelets ratio for prognosis of sepsis patients in the intensive care unit: a retrospective study

Background

Neutrophils to lymphocytes and platelets (N/LP) ratio has been confirmed as an indirect marker of inflammation. In this study, we aimed to further evaluate the prognostic significance of the N/LP ratio in sepsis patients admitted to the ICU.

Methods

Sepsis patients from the Affiliated Hospital of Jiangsu University were retrospectively enrolled from January 2015 and July 2023. The primary outcomes were 30/60 days mortality. The secondary outcomes included the incidence of AKI, vasoactive drug, CRRT, invasive ventilation, length of ICU stay, length of hospital stay and ICU mortality.

Results

A total of 1,066 sepsis patients were enrolled with a median age of 75.0 (66.0, 85.0) years, and 62.5% of them being male. The 30 days and 60 days mortality rates were found to be 28.7 and 34.0%, respectively, while the incidence of AKI was 45.2%. Based on their N/LP ratios, we classified the sepsis patients into three groups: low, middle, and high, consisting of 266, 534, and 266 patients, respectively. According the Cox proportional hazard model, the middle and high N/LP groups were associated with a 1.990/3.106-fold increase in 30 days mortality risk and a 2.066/3.046-fold increase in 60 days mortality risk compared with the low N/LP group. Besides, multivariate logistic regression model suggested that the risk of AKI occurrence increased 2.460 fold in the high group compared to the low group. However, through subgroup analyses, we observed substantial variations in the association between N/LP ratios and 30/60 days mortality rates as well as the incidence of AKI among different populations. Notably, the N/LP ratio measured at ICU admission exhibited a higher AUC for predicting 30/60 days mortality (0.684/0.687). Additionally, we observed a good predictive power for the occurrence of AKI (AUC: 0.645) using the N/LP ratio measured at sepsis prognosis. Regarding the other secondary outcomes, the N/LP ratio was associated with disease severity in sepsis patients, including the need for vasoactive drugs, length of ICU stay, and ICU mortality.

Conclusion

The N/LP ratio at ICU admission was found to have a significant independent association with 30/60 days mortality and the incidence of AKI in sepsis patients.

Effect of hot-melt extruded Morus alba leaves on intestinal microflora and epithelial cells

Although rutin and isoquercitrin have many effects, they are insoluble substances, making it difficult to obtain pure substances. This study was to investigate whether Morus alba leaves containing rutin and isoquercitrin could improve intestinal health by making a sustained-release formulation through a hot-melt extrusion (HME) process with improved stability and solubility and determine whether it could upregulate the balance of intestinal microorganisms and intestinal epithelial cells. A sustained-release formulation was prepared by the HME process using Morus alba leaves and a hydrophilic polymer matrix. Antibacterial activities of pathogenic microorganisms (Escherichia coli, Streptococcus aureus, Enterococcus faecalis) and proliferative effect of probiotics (Lactobacillus rhamnosus, Pediococcus pentosaceus) were tested against intestinal microorganisms. Regarding intestinal epithelial cells, a co-culture model of Caco-2 cells and RAW 264.7 cells was used. It was confirmed that the extrudate exhibited high antibacterial activities against pathogenic microorganisms and affected the proliferation of probiotics. Furthermore, after inducing inflammation through LPS, it recovered transepithelial electrical resistance-increased levels of tight junction proteins and decreased expression levels of pro-inflammatory cytokines. HME of Morus alba leaves containing rutin and isoquercitrin can upregulate intestinal microbial balance and intestinal epithelial cells.

The importance of the gut microbiome and its signals for a healthy nervous system and the multifaceted mechanisms of neuropsychiatric disorders

Increasing evidence links the gut microbiome and the nervous system in health and disease. This narrative review discusses current views on the interaction between the gut microbiota, the intestinal epithelium, and the brain, and provides an overview of the communication routes and signals of the bidirectional interactions between gut microbiota and the brain, including circulatory, immunological, neuroanatomical, and neuroendocrine pathways. Similarities and differences in healthy gut microbiota in humans and mice exist that are relevant for the translational gap between non-human model systems and patients. There is an increasing spectrum of metabolites and neurotransmitters that are released and/or modulated by the gut microbiota in both homeostatic and pathological conditions. Dysbiotic disruptions occur as consequences of critical illnesses such as cancer, cardiovascular and chronic kidney disease but also neurological, mental, and pain disorders, as well as ischemic and traumatic brain injury. Changes in the gut microbiota (dysbiosis) and a concomitant imbalance in the release of mediators may be cause or consequence of diseases of the central nervous system and are increasingly emerging as critical links to the disruption of healthy physiological function, alterations in nutrition intake, exposure to hypoxic conditions and others, observed in brain disorders. Despite the generally accepted importance of the gut microbiome, the bidirectional communication routes between brain and gut are not fully understood. Elucidating these routes and signaling pathways in more detail offers novel mechanistic insight into the pathophysiology and multifaceted aspects of brain disorders.

Epigenetic modification of m6A methylation: Regulatory factors, functions and mechanism in inflammatory bowel disease

Although the exact cause of inflammatory bowel disease (IBD) is still unknown, there is a lot of evidence to support the notion that it results from a combination of environmental factors, immune system issues, gut microbial changes, and genetic susceptibility. In recent years, the role of epigenetics in the pathogenesis of IBD has drawn increasing attention. The regulation of IBD-related immunity, the preservation of the intestinal epithelial barrier, and autophagy are all significantly influenced by epigenetic factors. The most extensive epigenetic methylation modification of mammalian mRNA among them is N6-methyladenosine (m6A). It summarizes the general structure and function of the m6A regulating factors, as well as their complex effects on IBD by regulating the intestinal mucous barrier, intestine mucosal immunity, epidermal cell death, and intestinal microorganisms.This paper provides key insights for the future identification of potential new targets for the diagnosis and treatment of IBD.

Natural Products as Dietary Agents for the Prevention and Mitigation of Oxidative Damage and Inflammation in the Intestinal Barrier

Food intake is a basic need to sustain life, but foodborne pathogens and food-related xenobiotics are also the main health concerns regarding intestinal barrier homeostasis. With a predominant role in the well-being of the entire human body, intestinal barrier homeostasis is strictly regulated by epithelial and immune cells. These cells are also the main intervenients in oxidative stress and inflammation-related diseases in the intestinal tract, triggered, for example, by genetic/epigenetic factors, food additives, pesticides, drugs, pathogens, and their metabolites. Nevertheless, the human diet can also be seen as a solution for the problem, mainly via the inclusion of functional foods or nutraceuticals that may act as antioxidant/anti-inflammatory agents to prevent and mitigate acute and chronic oxidative damage and inflammation. A literature analysis of recent advances in this topic highlights the significant role of Nrf2 (nuclear factor erythroid 2-related factor 2) and NF-kB (nuclear factor kappa-light-chain-enhancer of activated B cells) pathways in these biological processes, with many natural products and phytochemicals targeting endogenous antioxidant systems and cytokine production and balance. In this review, we summarized and discussed studies using in vitro and in vivo models of the intestinal tract used to reproduce oxidative damage and inflammatory events, as well as the role of natural products as modulators of Nrf2 and NK-kB pathways.

Epithelial-immune cell interactions in allergic diseases

Epithelial/immune interactions are characterized by the different properties of the various epithelial tissues, the mediators involved, and the varying immune cells that initiate, sustain, or abrogate allergic diseases on the surface. The intestinal mucosa, respiratory mucosa, and regular skin feature structural differences according to their primary function and surroundings. In the context of these specialized functions, the active role of the epithelium in shaping immune responses is increasingly recognizable. Crosstalk between epithelial and immune cells plays an important role in maintaining homeostatic conditions. While cells of the myeloid cell lineage, mainly macrophages, are the dominating immune cell population in the skin and the respiratory tract, lymphocytes comprise most intraepithelial immune cells in the intestine under healthy conditions. Common to all surface epithelia is the fact that innate immune cells represent the first line of immunosurveillance that either directly defeats invading pathogens or initiates and coordinates more effective successive immune responses involving adaptive immune cells and effector cells. Pharmacological approaches for the treatment of allergic and chronic inflammatory diseases involving epithelial barriers target immunological mediators downstream of the epithelium (such as IL-4, IL-5, IL-13, and IgE). The next generation of therapeutics involves upstream events of the inflammatory cascade, such as epithelial-derived alarmins and related mediators.

Bacteriocins: Curial guardians of gastrointestinal tract

The human gastrointestinal (GI) tract microbiome secretes various metabolites that play pivotal roles in maintaining host physiological balance and influencing disease progression. Among these metabolites, bacteriocins-small, heat-stable peptides synthesized by ribosomes-are notably prevalent in the GI region. Their multifaceted benefits have garnered significant interest in the scientific community. This review comprehensively explores the methods for mining bacteriocins (traditional separation and purification, bioinformatics, and artificial intelligence), their effects on the stomach and intestines, and their complex bioactive mechanisms. These mechanisms include flora regulation, biological barrier restoration, and intervention in epithelial cell pathways. By detailing each well-documented bacteriocin, we reveal the diverse ways in which bacteriocins interact with the GI environment. Moreover, the future research direction is prospected. By further studying the function and interaction of intestinal bacteriocins, we can discover new pharmacological targets and develop drugs targeting intestinal bacteriocins to regulate and improve human health. It provides innovative ideas and infinite possibilities for further exploration, development, and utilization of bacteriocins. The inevitable fact is that the continuously exploration of bacteriocins is sure to bring the promising future for demic GI health understanding and interference strategy.

Immunological Regulation of Gut-Tropic Immune Cells by Extracellular Vesicles

The remarkable diversity of lymphocytes, essential components of the immune system, serves as an ingenious mechanism for maximizing the efficient utilization of limited host defense resources. While cell adhesion molecules, notably in gut-tropic T cells, play a central role in this mechanism, the counterbalancing molecular details have remained elusive. Conversely, we've uncovered the molecular pathways enabling extracellular vesicles secreted by lymphocytes to reach the gut's mucosal tissues, facilitating immunological regulation. This discovery sheds light on immune fine-tuning, offering insights into immune regulation mechanisms.

Direct therapeutic effect of sulfadoxine-pyrimethamine on nutritional deficiency-induced enteric dysfunction in a human Intestine Chip

BACKGROUND

Sulfadoxine-pyrimethamine (SP) antimalarial therapy has been suggested to potentially increase the birth weight of infants in pregnant women in sub-Saharan Africa, independently of malarial infection. Here, we utilized female intestinal organoid-derived cells cultured within microfluidic Organ Chips to investigate whether SP could directly impact intestinal function and thereby improve the absorption of essential fats and nutrients crucial for fetal growth.

METHODS

Using a human organ-on-a-chip model, we replicated the adult female intestine with patient organoid-derived duodenal epithelial cells interfaced with human intestinal endothelial cells. Nutrient-deficient (ND) medium was perfused to simulate malnutrition, resulting in the appearance of enteric dysfunction indicators such as villus blunting, reduced mucus production, impaired nutrient absorption, and increased inflammatory cytokine secretion. SP was administered to these chips in the presence or absence of human peripheral blood mononuclear cells (PBMCs).

FINDINGS

Our findings revealed that SP treatment effectively reversed multiple intestinal absorptive abnormalities observed in malnourished female Intestine Chips, as validated by transcriptomic and proteomic analyses. SP also reduced the production of inflammatory cytokines and suppressed the recruitment of PBMCs in ND chips.

INTERPRETATION

Our results indicate that SP could potentially increase birth weights by preventing enteric dysfunction and suppressing intestinal inflammation. This underscores the potential of SP as a targeted intervention to improve maternal absorption, subsequently contributing to healthier fetal growth. While SP treatment shows promise in addressing malabsorption issues that can influence infant birth weight, we did not model pregnancy in our chips, and thus its usefulness for treatment of malnourished pregnant women requires further investigation through clinical trials.

FUNDING

The Bill and Melinda Gates Foundation, and the Wyss Institute for Biologically Inspired Engineering at Harvard University, and the HDDC Organoid Core of the P30 DK034854.

Effects of Peanuts and Pistachios on Gut Microbiota and Metabolic Syndrome: A Review

There is growing evidence that the gut microbiota is associated with various aspects of human health, including immune system regulation, vitamin synthesis, short-chain fatty acid production, etc. Peanuts and pistachios are foods rich in protein, unsaturated fatty acids, vitamins, polyphenols, and other dietary components that have been shown to benefit the gut microbiota. Therefore, this review aims to describe the effects of consuming peanuts and pistachios on the gut microbiota and the potential role of these microbiota in human health. This review suggests that the consumption of peanuts or pistachios can demonstrate the potential to exert a beneficial effect on the gut microbiota by promoting the growth of beneficial gut bacteria that produce, for example, short-chain fatty acids that are beneficial for human health. In the case of peanuts, in particular, the possible modulation of the microbiota is associated with an improvement in the risk factors of metabolic syndrome and the inflammatory process triggered by a high-fat diet.

Lcn2 deficiency accelerates the infection of Escherichia coli O157:H7 by disrupting the intestinal barrier function

Bacterial infections result in intestinal inflammation and injury, which affects gut health and nutrient absorption. Lipocalin 2 (Lcn2) is a protein that reacts to microbial invasion, inflammatory responses, and tissue damage. However, it remains unclear whether Lcn2 has a protective effect against bacterial induced intestinal inflammation. Therefore, this study endeavors to investigate the involvement of Lcn2 in the intestinal inflammation of mice infected with Enterohemorrhagic Escherichia coli O157:H7 (E. coli O157:H7). Lcn2 knockout (Lcn2-/-) mice were used to evaluate the changes of inflammatory responses. Lcn2 deficiency significantly exacerbated clinical symptoms of E. coli O157:H7 infection by reducing body weight and encouraging bacterial colonization of. Compared to infected wild type mice, infected Lcn2-/- mice had significantly elevated levels of pro-inflammatory cytokines in serum and ileum, including interleukin (IL)-6, IL-1β, and tumor necrosis factor-α (TNF-α), as well as severe villi destruction in the jejunum. Furthermore, Lcn2 deficiency aggravated intestinal barrier degradation by significantly reducing the expression of tight junction proteins occludin and claudin 1, the content of myeloperoxidase (MPO) in the ileum, and the number of goblet cells in the colon. Our findings indicated that Lcn2 could alleviate inflammatory damage caused by E. coli O157:H7 infection in mice by enhancing intestinal barrier function.

Protective effect of hydrangenol on lipopolysaccharide-induced endotoxemia by suppressing intestinal inflammation

Hydrangenol, a dihydroisocoumarin, isolated from the leaves of Hydrangea serrata, possesses anti-inflammatory, anti-obesity, and anti-photoaging activities. In this study, we investigated the protective effects of hydrangenol (HG) against lipopolysaccharide (LPS)-induced endotoxemia and elucidated the underlying molecular mechanisms of action in C57BL/6 mice. Oral administration of HG (20 or 40 mg/kg) significantly restored the survival rate and population of macrophages, T helper cells (CD3+/CD4+), and Th17 cells (CD3+/CD4+/CCR6+) in the spleens of mice with LPS-induced endotoxemia. HG suppressed the expression of pro-inflammatory cytokines such as tumor necrosis factor-α (TNF-α), interleukin (IL)-6, IL-1β, and Interferon (IFN)-γ and the mRNA and protein expressions of inducible NO synthase (iNOS) and cyclooxygenase-2 (COX-2) in the intestine and lung of LPS-treated mice. Molecular data showed that HG ameliorated the activation of nuclear factor kappa B (NF-κB) p65, signal transducers and activators of transcription 3 (STAT3), and c-Fos and c-Jun (AP-1 subunits) via the myeloid differentiation primary response 88 (MyD88) dependent toll-like receptor 4 (TLR4) signaling pathway in the LPS-treated mouse intestines. HG treatment caused the recovery of LPS-induced impaired tight junction (occludin and claudin-2) protein and mRNA expressions. Furthermore, HG improved LPS-induced gut dysbiosis in mice. Taken together, our results suggest that HG protects against LPS-induced endotoxemia by restoring immune cells and the capacity of the intestinal barrier, reducing intestinal inflammation, and improving the composition of the gut microbiota.

A foundational approach to culture and analyze malnourished organoids

The gastrointestinal (GI) epithelium plays a major role in nutrient absorption, barrier formation, and innate immunity. The development of organoid-based methodology has significantly impacted the study of the GI epithelium, particularly in the fields of mucosal biology, immunity, and host-microbe interactions. Various effects on the GI epithelium, such as genetics and nutrition, impact patients and alter disease states. Thus, incorporating these effects into organoid-based models will facilitate a better understanding of disease progression and offer opportunities to evaluate therapeutic candidates. One condition that has a significant effect on the GI epithelium is malnutrition, and studying the mechanistic impacts of malnutrition would enhance our understanding of several pathologies. Therefore, the goal of this study was to begin to develop methodology to generate viable malnourished organoids with accessible techniques and resources that can be used for a wide array of mechanistic studies. By selectively limiting distinct macronutrient components of organoid media, we were able to successfully culture and evaluate malnourished organoids. Genetic and protein-based analyses were used to validate the approach and confirm the presence of known biomarkers of malnutrition. Additionally, as proof-of-concept, we utilized malnourished organoid-derived monolayers to evaluate the effect of malnourishment on barrier formation and the ability of the bacterial pathogen Shigella flexneri to infect the GI epithelium. This work serves as the basis for new and exciting techniques to alter the nutritional state of organoids and investigate the related impacts on the GI epithelium.

Parvimonas micra, an oral pathobiont associated with colorectal cancer, epigenetically reprograms human colonocytes

Recently, an intestinal dysbiotic microbiota with enrichment in oral cavity bacteria has been described in colorectal cancer (CRC) patients. Here, we characterize and investigate one of these oral pathobionts, the Gram-positive anaerobic coccus Parvimonas micra. We identified two phylotypes (A and B) exhibiting different phenotypes and adhesion capabilities. We observed a strong association of phylotype A with CRC, with its higher abundance in feces and in tumoral tissue compared with the normal homologous colonic mucosa, which was associated with a distinct methylation status of patients. By developing an in vitro hypoxic co-culture system of human primary colonic cells with anaerobic bacteria, we show that P. micra phylotype A alters the DNA methylation profile promoters of key tumor-suppressor genes, oncogenes, and genes involved in epithelial-mesenchymal transition. In colonic mucosa of CRC patients carrying P. micra phylotype A, we found similar DNA methylation alterations, together with significant enrichment of differentially expressed genes in pathways involved in inflammation, cell adhesion, and regulation of actin cytoskeleton, providing evidence of P. micra's possible role in the carcinogenic process.

Modeling gut neuro-epithelial connections in a novel microfluidic device

The intestinal lumen is filled with diverse chemical and physical stimuli. Intestinal epithelial cells sense these stimuli and signal to enteric neurons which coordinate a range of physiologic processes required for normal digestive tract function. Yet, the neuro-epithelial connections remain poorly resolved, in part because the tools for orchestrating interactions between these cellular compartments are lacking. We describe the development of a two-compartment microfluidic device for co-culturing enteric neurons with intestinal epithelial cells. The device contains epithelial and neuronal compartments connected by microgrooves. The epithelial compartment was designed for cell seeding via injection and confinement of intestinal epithelial cells derived from human intestinal organoids. We demonstrated that organoids planarized effectively and retained epithelial phenotype for over a week. In the second chamber we dissociated and cultured intestinal myenteric neurons including intrinsic primary afferent neurons (IPANs) from transgenic mice that expressed the fluorescent protein tdTomato. IPANs extended projections into microgrooves, surrounded and frequently made contacts with epithelial cells. The density and directionality of neuronal projections were enhanced by the presence of epithelial cells in the adjacent compartment. Our microfluidic device represents a platform that may, in the future, be used to dissect structure and function of neuro-epithelial connections in the gut and other organs (skin, lung, bladder, and others) in health and disease.

The oral bacterial microbiota facilitates the stratification for ulcerative colitis patients with oral ulcers

BACKGROUND

Clinically, a large part of inflammatory bowel disease (IBD) patients is complicated by oral lesions. Although previous studies proved oral microbial dysbiosis in IBD patients, the bacterial community in the gastrointestinal (GI) tract of those IBD patients combined with oral ulcers has not been profiled yet.

METHODS

In this study, we enrolled four groups of subjects, including healthy controls (CON), oral ulcer patients (OU), and ulcerative colitis patients with (UC_OU) and without (UC) oral ulcers. Bio-samples from three GI niches containing salivary, buccal, and fecal samples, were collected for 16S rRNA V3-V4 region sequencing. Bacterial abundance and related bio-functions were compared, and data showed that the fecal microbiota was more potent than salivary and buccal microbes in shaping the host immune system. ~ 22 UC and 10 UC_OU 5-aminosalicylate (5-ASA) routine treated patients were followed-up for six months; according to their treatment response (a decrease in the endoscopic Mayo score), they were further sub-grouped as responding and non-responding patients.

RESULTS

We found those UC patients complicated with oral ulcers presented weaker treatment response, and three oral bacterial genera, i.e., Fusobacterium, Oribacterium, and Campylobacter, might be connected with treatment responding. Additionally, the salivary microbiome could be an indicator of treatment responding in 5-ASA routine treatment rather than buccal or fecal ones.

CONCLUSIONS

The fecal microbiota had a strong effect on the host's immune indices, while the oral bacterial microbiota could help stratification for ulcerative colitis patients with oral ulcers. Additionally, the oral microbiota had the potential role in reflecting the treatment response of UC patients. Three oral bacteria genera (Fusobacterium, Oribacterium, and Campylobacter) might be involved in UC patients with oral ulcers lacking treatment responses, and monitoring oral microbiota may be meaningful in assessing the therapeutic response in UC patients.

Identification of OLA1 as a Novel Protein Target of Vitexin to Ameliorate Dextran Sulfate Sodium-Induced Colitis with Tissue Thermal Proteome Profiling

Vitexin, which exists in various medicinal plants and food sources, has recently received increasing attention because of its anti-inflammatory properties. This study aims to identify the protein target of vitexin that ameliorates dextran sulfate sodium (DSS)-induced colitis. The results showed that vitexin not only alleviated the clinical symptoms and colonic damage in mice with DSS-induced colitis but also suppressed the colonic production of inflammatory cytokines (IL-1β, IL-6, ICAM, and VCAM) and enhanced the expression of barrier-associated proteins (ZO-1, Occludin, and E-cadherin). Based on tissue thermal proteome profiling (Tissue-TPP) and molecular docking, OLA1 was creatively identified as a potential protein target for vitexin. Further siRNA-mediated knockdown of the OLA1 gene in Caco-2 cells demonstrated the ability of OLA1 to increase Nrf2 protein expression and, thus, mediated the anti-inflammatory effects of vitexin. Interaction of the OLA1-vitexin complex with Keap1 protein to disrupt the Keap1-Nrf2 interaction may be required for activating Nrf2. Our findings revealed a novel role for OLA1 as a protein target of vitexin that contributes to its anti-inflammatory action by activating Nrf2, which may provide a promising molecular mechanism for novel therapeutic strategies to treat colitis and the associated systemic inflammation.

Human gut homeostasis and regeneration: the role of the gut microbiota and its metabolites

The healthy human gut is a balanced ecosystem where host cells and representatives of the gut microbiota interact and communicate in a bidirectional manner at the gut epithelium. As a result of these interactions, many local and systemic processes necessary for host functionality, and ultimately health, take place. Impairment of the integrity of the gut epithelium diminishes its ability to act as an effective gut barrier, can contribute to conditions associated to inflammation processes and can have other negative consequences. Pathogens and pathobionts have been linked with damage of the integrity of the gut epithelium, but other components of the gut microbiota and some of their metabolites can contribute to its repair and regeneration. Here, we review what is known about the effect of bacterial metabolites on the gut epithelium and, more specifically, on the regulation of repair by intestinal stem cells and the regulation of the immune system in the gut. Additionally, we explore the potential therapeutic use of targeted modulation of the gut microbiota to maintain and improve gut homeostasis as a mean to improve health outcomes.

Enteroendocrine cells and gut hormones as potential targets in the crossroad of the gut-kidney axis communication

Recent studies suggest that disruptions in intestinal homeostasis, such as changes in gut microbiota composition, infection, and inflammatory-related gut diseases, can be associated with kidney diseases. For instance, genomic investigations highlight how susceptibility genes linked to IgA nephropathy are also correlated with the risk of inflammatory bowel disease. Conversely, investigations demonstrate that the use of short-chain fatty acids, produced through fermentation by intestinal bacteria, protects kidney function in models of acute and chronic kidney diseases. Thus, the dialogue between the gut and kidney seems to be crucial in maintaining their proper function, although the factors governing this crosstalk are still emerging as the field evolves. In recent years, a series of studies have highlighted the significance of enteroendocrine cells (EECs) which are part of the secretory lineage of the gut epithelial cells, as important components in gut-kidney crosstalk. EECs are distributed throughout the epithelial layer and release more than 20 hormones in response to microenvironment stimuli. Interestingly, some of these hormones and/or their pathways such as Glucagon-Like Peptide 1 (GLP-1), GLP-2, gastrin, and somatostatin have been shown to exert renoprotective effects. Therefore, the present review explores the role of EECs and their hormones as regulators of gut-kidney crosstalk and their potential impact on kidney diseases. This comprehensive exploration underscores the substantial contribution of EEC hormones in mediating gut-kidney communication and their promising potential for the treatment of kidney diseases.

Gut microecological regulation on bronchiolitis and asthma in children: A review

INTRODUCTION

Asthma and bronchiolitis in children are considered common clinical problems associated with gut microbiota. However, the exact relationship between gut microbiota and the above-mentioned diseases remains unclear. Here, we discussed recent advances in understanding the potential mechanism underlying immune regulation of gut microbiota on asthma and bronchiolitis in children as well as the role of the gut-lung axis.

METHODS

We retrieved and assessed all relevant original articles related to gut microbiota, airway inflammation-induced wheezing in children, and gut-lung axis studies from databases that have been published so far, including PubMed/MEDLINE, Scopus, Google Scholar, China National Knowledge Infrastructure (CNKI) and the Wanfang Database.

RESULTS

The infant period is critical for the development of gut microbiota, which can be influenced by gestational age, delivery mode, antibiotic exposure and feeding mode. The gut microbiota in children with asthma and bronchiolitis is significantly distinct from those in healthy subjects. Gut microbiota dysbiosis is implicated in asthma and bronchiolitis in children. The presence of intestinal disturbances in lung diseases highlights the importance of the gut-lung axis.

CONCLUSION

Gut microbiota dysbiosis potentially increases the risk of asthma and bronchiolitis in children. Moreover, a deeper understanding of the gut-lung axis with regard to the gut microbiota of children with respiratory diseases could contribute to clinical practice for pulmonary diseases.

Mucosa-Mimetic Materials for the Study of Intestinal Homeostasis and Disease

Mucus is a viscoelastic hydrogel that lines and protects the epithelial surfaces of the body that houses commensal microbiota and functions in host defense against pathogen invasion. As a first-line physical and biochemical barrier, intestinal mucus is involved in immune surveillance and spatial organization of the microbiome, while dysfunction of the gut mucus barrier is implicated in several diseases. Mucus can be collected from a variety of mammalian sources for study, however, established methods are challenging in terms of scale and efficiency, as well as with regard to rheological similarity to native human mucus. Therefore, there is a need for mucus-mimetic hydrogels that more accurately reflect the physical and chemical profile of the in vivo human epithelial environment to enable the investigation of the role of mucus in human disease and interactions with the intestinal microbiome. This review will evaluate the material properties of synthetic mucus mimics to date designed to address the above need, with a focus toward an improved understanding of the biochemical and immunological functions of these biopolymers related to utility for research and therapeutic applications.

Modeling Gut Neuro-Epithelial Connections in a Novel Micro uidic Device

Organs that face external environments, such as skin and gut, are lined by epithelia, which have two functions - to provide a semi-permeable barrier and to sense stimuli. The intestinal lumen is filled with diverse chemical and physical stimuli. Intestinal epithelial cells sense these stimuli and signal to enteric neurons which coordinate a range of physiologic processes required for normal digestive tract function. Yet, the neuro-epithelial connections between intestinal epithelial cells and enteric neurons remain poorly resolved, which leaves us with limited mechanistic understanding of their function. We describe the development of a two-compartment microfluidic device for modeling neuro-epithelial interactions, and apply it to form the gut's neuro-epithelial connections. The device contains epithelial and neuronal compartments connected by microgrooves. The epithelial compartment was designed for cell seeding via injection and confinement of intestinal epithelial cells derived from human intestinal organoids. We demonstrated that organoids planarized effectively and retained epithelial phenotype for over a week. In the second chamber we dissociated and cultured intestinal myenteric neurons including intrinsic primary afferent neurons (IPANs) from transgenic mice that expressed the fluorescent protein tdTomato. IPANs extended projections into microgrooves, surrounded and frequently made contacts with epithelial cells. The density and directionality of neuronal projections were enhanced by the presence of epithelial cells in the adjacent compartment. Our microfluidic device represents a platform for dissecting structure and function of neuro-epithelial connections in the gut and other organs (skin, lung, bladder, and others) in health and disease.

The direct and gut microbiota-mediated effects of dietary bile acids on the improvement of gut barriers in largemouth bass (Micropterus salmoides)

Fish gut barrier damage under intensive culture model is a significant concern for aquaculture industry. This study aimed to investigate the effects of bile acids (BAs) on gut barriers in Micropterus salmoides. A germ-free (GF) zebrafish model was employed to elucidate the effects of the direct stimulation of BAs and the indirect regulations mediated by the gut microbiota on gut barrier functions. Four diets were formulated with BAs supplemented at 0, 150, 300 and 450 mg/kg, and these 4 diets were defined as control, BA150, BA300 and BA450, respectively. After 5 weeks of feeding experiment, the survival rate of fish fed with BA300 diet was increased (P < 0.05). Histological analysis revealed an improvement of gut structural integrity in the BA150 and BA300 groups. Compared with the control group, the expression of genes related to chemical barrier (mucin, lysozyme and complement 1) and physical barrier (occludin and claudin-4) was increased in the BA150 and BA300 groups (P < 0.05), and the expression of genes related to immunological barrier (interleukin [IL]-6, tumor growth factor β, IL-10, macrophage galactose-type lectin and immunoglobulin M [IgM]) was significantly increased in the BA300 group (P < 0.05), but the expression of genes related to chemical barrier (hepcidin) and immunological barrier (IL-1β, tumor necrosis factor-α, IL-6 and arginase) was significantly decreased in the BA450 group (P < 0.05). Gut microbiota composition analysis revealed that the abundance of Firmicutes was augmented prominently in the BA150 and BA300 groups (P < 0.05), while that of Actinobacteriota and Proteobacteria showed a downward trend in the BA150 and BA300 groups (P > 0.05). The results of the gut microbiota transferring experiment demonstrated an upregulation of gut barrier-related genes, including immunoglobulin Z/T (IgZ/T), IL-6, IL-1β and IL-10, by the gut microbiota transferred from the BA300 group compared with the control (P < 0.05). Feeding the BA300 diet directly to GF zebrafish resulted in enhanced expression of IgM, IgZ/T, lysozyme, occludin-2, IL-6 and IL-10 (P < 0.05). In conclusion, BAs can improve the gut barriers of fish through both direct and indirect effects mediated by the gut microbiota.

Loss of ERβ in Aging LXRαβ Knockout Mice Leads to Colitis

Liver X receptors (LXRα and LXRβ) are oxysterol-activated nuclear receptors that play key roles in cholesterol homeostasis, the central nervous system, and the immune system. We have previously reported that LXRαβ-deficient mice are more susceptible to dextran sodium sulfate (DSS)-induced colitis than their WT littermates, and that an LXR agonist protects against colitis in mice mainly via the regulation of the immune system in the gut. We now report that both LXRα and LXRβ are expressed in the colonic epithelium and that in aging LXRαβ-/- mice there is a reduction in the intensity of goblet cells, mucin (MUC2), TFF3, and estrogen receptor β (ERβ) levels. The cytoplasmic compartment of the surface epithelial cells was markedly reduced and there was a massive invasion of macrophages in the lamina propria. The expression and localization of β-catenin, α-catenin, and E-cadherin were not changed, but the shrinkage of the cytoplasm led to an appearance of an increase in staining. In the colonic epithelium there was a reduction in the expression of plectin, a hemidesmosome protein whose loss in mice leads to spontaneous colitis, ELOVL1, a fatty acid elongase protein coding gene whose overexpression is found in colorectal cancer, and non-neuronal choline acetyltransferase (ChAT) involved in the regulation of epithelial cell adhesion. We conclude that in aging LXRαβ-/- mice, the phenotype in the colon is due to loss of ERβ expression.

The microbiome in post-acute infection syndrome (PAIS)

Post-Acute Infection Syndrome (PAIS) is a relatively new medical terminology that represents prolonged sequelae symptoms after acute infection by numerous pathogenic agents. Imposing a substantial public health burden worldwide, PASC (post-acute sequelae of COVID-19 infection) and ME/CFS (myalgic encephalomyelitis/chronic fatigue syndrome) are two of the most recognized and prevalent PAIS conditions. The presences of prior infections and similar symptom profiles in PAIS reflect a plausible common etiopathogenesis. The human microbiome is known to play an essential role in health and disease. In this review, we reviewed and summarized available research on oral and gut microbiota alterations in patients with different infections or PAIS conditions. We discussed key theories about the associations between microbiome dysbiosis and PAIS disease development, aiming to explore the mechanistic roles and potential functions the microbiome may have in the process. Additionally, we discuss the areas of knowledge gaps and propose the potential clinical applications of the microbiome for prevention and treatment of PAIS conditions.

Building better barriers: how nutrition and undernutrition impact pediatric intestinal health

Chronic undernutrition is a major cause of death for children under five, leaving survivors at risk for adverse long-term consequences. This review focuses on the role of nutrients in normal intestinal development and function, from the intestinal epithelium, to the closely-associated mucosal immune system and intestinal microbiota. We examine what is known about the impacts of undernutrition on intestinal physiology, with focus again on the same systems. We provide a discussion of existing animal models of undernutrition, and review the evidence demonstrating that correcting undernutrition alone does not fully ameliorate effects on intestinal function, the microbiome, or growth. We review efforts to treat undernutrition that incorporate data indicating that improved recovery is possible with interventions focused not only on delivery of sufficient energy, macronutrients, and micronutrients, but also on efforts to correct the abnormal intestinal microbiome that is a consequence of undernutrition. Understanding of the role of the intestinal microbiome in the undernourished state and correction of the phenotype is both complex and a subject that holds great potential to improve recovery. We conclude with critical unanswered questions in the field, including the need for greater mechanistic research, improved models for the impacts of undernourishment, and new interventions that incorporate recent research gains. This review highlights the importance of understanding the mechanistic effects of undernutrition on the intestinal ecosystem to better treat and improve long-term outcomes for survivors.

Potent Intestinal Mucosal Barrier Enhancement of Nostoc commune Vaucher Polysaccharide Supplementation Ameliorates Acute Ulcerative Colitis in Mice Mediated by Gut Microbiota

Ulcerative colitis (UC) is evolving into a global burden with a substantially increasing incidence in developing countries. It is characterized by inflammation confined to mucosa and is recognized as an intestinal barrier disease. The intestinal microbiota plays a crucial role in UC pathogenesis. N. commune has long been appreciated as a healthy food and supplement worldwide and polysaccharides account for 60%. Here, we examined the amelioration of N. commune polysaccharides against acute colitis in mice induced by DSS and assessed the mediating role of gut microbiota. An integrated analysis of microbiome, metabolomics, and transcriptomics fully elaborated it markedly enhanced intestinal mucosal barrier function, including: increasing the relative abundance of Akkermansia muciniphila, uncultured_bacterium_g__norank_f__Muribaculaceae, and unclassified_g__norank_f__norank_o__Clostridia_UCG-014; decreasing microbiota-derived phosphatidylcholines and thromboxane 2 levels mapped to arachidonic acid metabolism; improving mucin2 biosynthesis and secretion; enhancing ZO-1 and occludin expression; reducing neutrophil infiltration; regulating the level of colitis-related inflammatory cytokines; involving inflammation and immune function-associated signaling pathways. Further, the mediation effect of gut microbiota was evaluated by administering a cocktail of antibiotics. In conclusion, our results demonstrated that N. commune polysaccharides predominantly reinforced the gut microbiota-mediated intestinal mucosal barrier to confer protection against UC and exhibited dramatic prebiotic-like functions, providing an alternative or complementary treatment for UC.

ARF1 maintains intestinal homeostasis by modulating gut microbiota and stem cell function

AIMS

The small GTPase protein ARF1 has been shown to be involved in the lipolysis pathway and to selectively kill stem cells in Drosophila melanogaster. However, the role of ARF1 in mammalian intestinal homeostasis remains elusive. This study aimed to explore the role of ARF1 in intestinal epithelial cells (IECs) and reveal the possible mechanism.

MATERIALS AND METHODS

IEC-specific ARF1 deletion mouse model was used to evaluate the role of ARF1 in intestine. Immunohistochemistry and immunofluorescence analyses were performed to detect specific cell type markers, and intestinal organoids were cultured to assess intestinal stem cell (ISC) proliferation and differentiation. Fluorescence in situ hybridization, 16S rRNA-Seq analysis, and antibiotic treatments were conducted to elucidate the role of gut microbes in ARF1-mediated intestinal function and the underlying mechanism. Colitis was induced in control and ARF1-deficient mice by dextran sulfate sodium (DSS). RNA-seq was performed to elucidate the transcriptomic changes after ARF1 deletion.

KEY FINDINGS

ARF1 was essential for ISC proliferation and differentiation. Loss of ARF1 increased susceptibility to DSS-induced colitis and gut microbial dysbiosis. Gut microbiota depletion by antibiotics could rescue the intestinal abnormalities to a certain extent. Furthermore, RNA-Seq analysis revealed alterations in multiple metabolic pathways.

SIGNIFICANCE

This work is the first to elucidate the essential role of ARF1 in regulating gut homeostasis, and provides novel insights into the pathogenesis of intestinal diseases and potential therapeutic targets.

TGF-β controls development of TCRγδ+CD8αα+ intestinal intraepithelial lymphocytes

γδ intestinal intraepithelial lymphocytes (IELs) constitute the majority of IELs with unique CD8αα⁺ homodimers that are distinct from γδT cells in other tissues. However, it remains largely unclear how those cells develop. Here we show that transforming growth factor beta (TGF-β) signaling controls the development of TCRγδ⁺CD8αα⁺ IELs. Deletion of TGF-β receptors or Smad3 and Smad2 in bone marrow stem cells caused a deficiency of TCRγδ⁺CD8αα⁺ IELs in mixed bone marrow chimeric mice. Mechanistically, TGF-β is required for the development of TCRγδ⁺CD8αα⁺ IELs thymic precursors (CD44^-CD25^- γδ thymocytes). In addition, TGF-β signaling induced CD8α in thymic γδT cells and maintained CD8α expression and survival in TCRγδ⁺CD8αα⁺ IELs. Moreover, TGF-β also indirectly controls TCRγδ⁺CD8αα⁺ IELs by modulating the function of intestinal epithelial cells (IECs). Importantly, TGF-β signaling in TCRγδ⁺CD8αα⁺ IELs safeguarded the integrity of the intestinal barrier in dextran sulfate sodium (DSS)-induced colitis.

Intestinal Microbiota and miRNA in IBD: A Narrative Review about Discoveries and Perspectives for the Future

Inflammatory bowel disease (IBD) includes Crohn's disease (CD) and ulcerative colitis (UC) and comprises a chronic gastrointestinal tract disorder characterized by hyperactive and dysregulated immune responses to environmental factors, including gut microbiota and dietary components. An imbalance of the intestinal microbiota may contribute to the development and/or worsening of the inflammatory process. MicroRNAs (miRNAs) have been associated with various physiological processes, such as cell development and proliferation, apoptosis, and cancer. In addition, they play an important role in inflammatory processes, acting in the regulation of pro- and anti-inflammatory pathways. Differences in the profiles of miRNAs may represent a useful tool in the diagnosis of UC and CD and as a prognostic marker in both diseases. The relationship between miRNAs and the intestinal microbiota is not completely elucidated, but recently this topic has gained prominence and has become the target of several studies that demonstrate the role of miRNAs in the modulation of the intestinal microbiota and induction of dysbiosis; the microbiota, in turn, can regulate the expression of miRNAs and, consequently, alter the intestinal homeostasis. Therefore, this review aims to describe the interaction between the intestinal microbiota and miRNAs in IBD, recent discoveries, and perspectives for the future.

In Vitro Evaluation of the Most Active Probiotic Strains Able to Improve the Intestinal Barrier Functions and to Prevent Inflammatory Diseases of the Gastrointestinal System

Background: The integrity of the intestinal barrier is fundamental to gut health and homeostasis; its damage can increase intestinal permeability, with translocation of bacteria and/or endotoxins from gut, and the onset of various intestinal diseases. Lactobacillus spp. is one of the most common probiotics normally found in fermented foods and dairy products and is known for its anti-inflammatory and immunomodulatory properties and for its ability to protect and enhance the intestinal barrier functions. The aim of this work was to evaluate the ability of different strains of Lactobacillus spp. to improve in vitro the integrity of the intestinal barrier, to exert anti-inflammatory and immunomodulatory activity and to prevent Salmonella Typhimurium and enteroinvasive Escherichia coli (EIEC) infections. Methods: We analyzed the cellular expression of tight junctions, antimicrobial peptide HBD-2, pro-inflammatory cytokines and the inhibition of pathogens adhesion and invasion in a model of co-cultured epithelial cells treated with Lactobacillus spp. Results: L. brevis, L. reuteri and L. rhamnosus proved to be more effective in protecting the intestinal epithelium. Conclusions: These in vitro studies can help select strains particularly active in their intended use to obtain consortia formulations that can have as much maximum yield as possible in terms of patient benefit.

Vitamin A: a key coordinator of host-microbe interactions in the intestine

The human intestine is home to a dense community of microbiota that plays a key role in human health and disease. Nutrients are essential regulators of both host and microbial physiology and function as key coordinators of host-microbe interactions. Therefore, understanding the specific roles and underlying mechanisms of each nutrient in regulating the host-microbe interactions will be essential in developing new strategies for improving human health through microbiota and nutrient intervention. This review will give a basic overview of the role of vitamin A, an essential micronutrient, on human health, and highlight recent findings on the mechanisms by which it regulates the host-microbe interactions. [BMB Reports 2023; 56(3): 133-139].

Low-fat dairy consumption improves intestinal immune function more than high-fat dairy in a diet-induced swine model of insulin resistance

PURPOSE

To understand the effects of consuming high-fat and low-fat dairy products on postprandial cardiometabolic risk factors and intestinal immune function, we used an established low birthweight (LBW) swine model of diet-induced insulin resistance.

METHODS

LBW piglets were randomized to consume one of the 3 experimental high fat diets and were fed for a total of 7 weeks: (1) Control high fat (LBW-CHF), (2) CHF diet supplemented with 3 servings of high-fat dairy (LBW-HFDairy) and (3) CHF diet supplemented with 3 servings of low-fat dairy (LBW-LFDairy). As comparison groups, normal birthweight (NBW) piglets were fed a CHF (NBW-CHF) or standard pig grower diet (NBW-Chow). At 11 weeks of age, all piglets underwent an established modified oral glucose and fat tolerance test. At 12 weeks of age, piglets were euthanized and ex vivo cytokine production by cells isolated from mesenteric lymph node (MLN) stimulated with mitogens was assessed.

RESULTS

Dairy consumption did not modulate postprandial plasma lipid, inflammatory markers and glucose concentrations. A lower production of IL-2 and TNF-α after pokeweed mitogen (PWM) stimulation was observed in LBW-CHF vs NBW-Chow (P < 0.05), suggesting impaired MLN T cell function. While feeding high-fat dairy had minimal effects, feeding low-fat dairy significantly improved the production of IL-2 and TNF-α after PWM stimulation (P < 0.05).

CONCLUSIONS

Irrespective of fat content, dairy had a neutral effect on postprandial cardiometabolic risk factors. Low-fat dairy products improved intestinal T cell function to a greater extent than high-fat dairy in this swine model of obesity and insulin resistance.

MicroRNA Profiles in Intestinal Epithelial Cells in a Mouse Model of Sepsis

Sepsis is a systemic inflammatory disorder that leads to the dysfunction of multiple organs. In the intestine, the deregulation of the epithelial barrier contributes to the development of sepsis by triggering continuous exposure to harmful factors. However, sepsis-induced epigenetic changes in gene-regulation networks within intestinal epithelial cells (IECs) remain unexplored. In this study, we analyzed the expression profile of microRNAs (miRNAs) in IECs isolated from a mouse model of sepsis generated via cecal slurry injection. Among 239 miRNAs, 14 miRNAs were upregulated, and 9 miRNAs were downregulated in the IECs by sepsis. Upregulated miRNAs in IECs from septic mice, particularly miR-149-5p, miR-466q, miR-495, and miR-511-3p, were seen to exhibit complex and global effects on gene regulation networks. Interestingly, miR-511-3p has emerged as a diagnostic marker in this sepsis model due to its increase in blood in addition to IECs. As expected, mRNAs in the IECs were remarkably altered by sepsis; specifically, 2248 mRNAs were decreased, while 612 mRNAs were increased. This quantitative bias may be possibly derived, at least partly, from the direct effects of the sepsis-increased miRNAs on the comprehensive expression of mRNAs. Thus, current in silico data indicate that there are dynamic regulatory responses of miRNAs to sepsis in IECs. In addition, the miRNAs that were increased with sepsis had enriched downstream pathways including Wnt signaling, which is associated with wound healing, and FGF/FGFR signaling, which has been linked to chronic inflammation and fibrosis. These modifications in miRNA networks in IECs may lead to both pro- and anti-inflammatory effects in sepsis. The four miRNAs discovered above were shown to putatively target LOX, PTCH1, COL22A1, FOXO1, or HMGA2, via in silico analysis, which were associated with Wnt or inflammatory pathways and selected for further study. The expressions of these target genes were downregulated in sepsis IECs, possibly through posttranscriptional modifications of these miRNAs. Taken together, our study suggests that IECs display a distinctive miRNA profile which is capable of comprehensively and functionally reshaping the IEC-specific mRNA landscape in a sepsis model.

Toxic effects of glyphosate on histopathology and intestinal microflora of juvenile Litopenaeus vannamei

Glyphosate is a widely used broad-spectrum herbicide, its pollution to the surrounding conditions can't be ignored. It has been reported that glyphosate has poisonous impacts on aquatic animals. In this study, juvenile Litopenaeus vannamei (L. vannamei) was exposed to glyphosate, and the lethal concentration 50 (LC₅₀) of glyphosate to juvenile L. vannamei for 48 h was 47.6 mg/L. The histological analysis for intestine and hepatopancreas and the intestinal microorganisms of L. vannamei were evaluated after 48 h of exposure to glyphosate with LC₅₀. The histological analysis results showed that the lumen of hepatic tubules was diffused and deformed, the hepatic tubules were ruptured and intestinal villi were fallen off seriously after exposure to glyphosate for 48 h Moreover, the intestinal microbial composition and structure of L. vannamei were changed, with the abundance of Alphaproteobacteria increased significantly. The abundance of Rhodobacteraceae, Vibrio and Legionella increased, but there was no significant difference. The abundance of Bacillus, Paraburkholderia, Enhydrobacter, Comamonas and Alkanindiges decreased significantly. However, the homeostasis of intestinal microorganisms was destroyed. Phenotypic prediction of the two groups of microorganisms revealed a significant increase in the abundance of Facultatively Anaerobic in the glyphosate challenged group. This study suggested that hepatopancreas and intestinal tissue of L. vannamei were seriously damaged after 48 h of exposure to glyphosate with LC₅₀, and intestinal microbial homeostasis was disrupted.

Oral administration of Lactic acid bacteria inhibits PEDV infection in young piglets

Since the emergence of the highly pathogenic porcine epidemic diarrhea virus (PEDV) strain in 2010, the prevention of porcine epidemic diarrhea (PED) in pig farms remains problematic. To find the reasons behind the high mortality in young piglets, the relative mRNA expression of inflammation-related factors in infected pigs of different ages as well as uninfected pigs were detected by RT-qPCR. The results showed that the mRNA expression of these factors including IL-6 and TNF-α was more increased in infected younger piglets than infected older pigs. To clarify the relationship between these inflammation related factors, the pairwise linear correlation between the relative expression of these factors were analyzed and showed as network mapping with different correlation coefficients. A strong positive correlation was observed between the expression of various factors in 1-week-old piglets. Combined with the difference in mortality of PEDV infection in pigs of different ages, we hypothesized that lactic acid bacteria (LAB) could inhibit PEDV infection in newborn piglets, and an in vivo experiment was carried out. The results of survival rate and wet/dry ratio showed that LAB alleviated PEDV indued mortality and diarrhea. The detection of viral copies and tissue section staining showed less observed viruses in LAB treated pig. RT-qPCR results of gene expression in intestines showed that LAB modulated the gene expression of various host barrier genes, indicating that LAB is potential to inhibit PEDV infection by regulating the host intestinal barrier. However, to use LAB as therapy, how to improve the efficiency on inhibiting PEDV infection needs further studies.

Spatial transcriptomes and microbiota reveal immune mechanism that respond to pathogen infection in the posterior intestine of Sebastes schlegelii

The intestine is a site of immune cell priming at birth. Therefore, spatial transcriptomes were performed to define how the transcriptomic landscape was spatially organized in the posterior intestine of Sebastes schlegelii following Edwardsiella piscicida infection. In the healthy condition, we identified a previously unappreciated molecular regionalization of the posterior intestine. Following bacterial infection, most immune-related genes were identified in mucosa layer. Moreover, investigation of immune-related genes and genes in immune-related KEGG pathways based on spatial transcriptomes shed light on which sections of these genes are in the posterior intestine. Meanwhile, the high expression of genes related to regeneration also indicated that the posterior intestine was responding to the invasion of pathogens by constantly proliferating new cells. In addition, the increasing microbiota communities indicated that these bacteria maintained posterior intestine integrity and shaped the mucosal immune system. Taken together, spatial transcriptomes and microbiota compositions have significant implications for understanding the immune mechanism that responds to E. piscicida infection in the posterior intestine of S. schlegelii, which also provides a theoretical basis for the spatial distribution of immune genes and changes in bacterial flora in other teleosts in the process of resisting pathogens.