The Intestinal Epithelium: Central Coordinator of Mucosal Immunity

Alterations in metabolome and microbiome: new clues on cathelicidin-related antimicrobial peptide alleviates acute ulcerative colitis

Ulcerative colitis (UC) is a chronic and recurrent inflammatory disease of the gastrointestinal tract. This study aimed to determine the effect of cathelicidin-related antimicrobial peptide (Cramp) on dextran sulfate sodium (DSS)-induced acute experimental colitis in mice and to investigate the underlying mechanisms. Acute UC was induced in C57BL/6 mice with 3% DSS for 7 days, 4 mg/kg b.w. synthetic Cramp peptide was administrated once daily starting on day 4 of the experimental period. Mice were evaluated for body weight, colon length, colon histopathology, and inflammatory cytokines in colon tissue. Using 16 s rRNA sequencing, the composition structure of gut microbiota was characterized. Metabolomic profiling of the serum was performed. The results showed that DSS treatment significantly induced intestinal damage as reflected by disease activity index, histopathological features, and colon length, while Cramp treatment significantly prevented these trends. Meanwhile, Cramp treatment decreased the levels of inflammatory cytokines in both serum and colonic tissue on DSS-induced colitis. It was also observed that DSS damaged the integrity of the intestinal epithelial barrier, whereas Cramp also played a protective role by attenuating these deteriorated effects. Furthermore, Cramp treatment reversed the oxidative stress by increasing the antioxidant enzymes of GSH-PX and decreasing the oxidant content of MDA. Notably, compared to the DSS group, Cramp treatment significantly elevated the abundance of Verrucomicrobiota at the phylum level. Furthermore, at the genus level, Parasutterella and Mucispirllum abundance was increased significantly in response to Cramp treatment, although Roseburia and Enterorhabdus reduced remarkably. Metabolic pathway analysis of serum metabolomics showed that Cramp intervention can regulate various metabolic pathways such as α-linolenic acid, taurine and hypotaurine, sphingolipid, and arachidonic acid metabolism. The study concluded that Cramp significantly ameliorated DSS-induced colonic injury, colonic inflammation, and intestinal barrier dysfunction in mice. The underlying mechanism is closely related to the metabolic alterations derived from gut microbiota.

Moniezia benedeni drives CD3+ T cells residence in the sheep intestinal mucosal effector sites

Introduction

T cells are the core of the cellular immunity and play a key role in the regulation of intestinal immune homeostasis. In order to explore the impact Moniezia benedeni (M. benedeni) infection on distributions of CD3+ T cells in the small intestine of the sheep.

Methods

In this study, sheep pET-28a-CD3 recombinant plasmid were constructed and expressed in BL21 receptor cells, then the rabbit anti-sheep CD3 polyclonal antibody was prepared through recombinant protein inducing. The M. benedeni-infected sheep (infection group, n = 6) and healthy sheep (control group, n = 6) were selected, and the distributions of CD3+ T cells in intestinal laminae propria (LP) and mucous epitheliums were observed and analyzed systematically.

Results

The results showed that the rabbit anti-sheep CD3 polyclonal antibody had good potency and specificity. In the effector area of small intestine, a large number of CD3+ T cells were mainly diffusely distributed in the intestinal LP as well as in the mucous epitheliums, and the densities of intestinal LP from duodenum to jejunum to ileum were 6.01 cells/104 μm2, 7.01 cells/104 μm2 and 6.43 cells/104 μm2, respectively. Their distribution densities in mucous epitheliums were 6.71 cells/104 μm2, 7.93 cells/104 μm2 and 7.21 cells/104 μm2, respectively; in the infected group, the distributions of CD3+ T cells were similar to that of the control group, and the densities in each intestinal segment were all significantly increased (p < 0.05), meanwhile, the total densities of CD3+ T cells in duodenum, jejunum and ileum were increased by 33.43%, 14.50%, and 34.19%. In LP and mucous epitheliums, it was increased by 33.57% and 27.92% in duodenum; by 25.82% and 7.07% in jejunum, and by 27.07% and 19.23% in ileum, respectively.

Discussion

It was suggested that M. benedeni infection did not change the spatial distributions of CD3+ T cells in the small intestine of sheep, but significantly increased their densities, which lays a foundation for further research on the regulatory mechanism of sheep intestinal mucosal immune system against M. benedeni infection.

Listen to Your Gut: Key Concepts for Bioengineering Advanced Models of the Intestine

The intestine performs functions central to human health by breaking down food and absorbing nutrients while maintaining a selective barrier against the intestinal microbiome. Key to this barrier function are the combined efforts of lumen-lining specialized intestinal epithelial cells, and the supportive underlying immune cell-rich stromal tissue. The discovery that the intestinal epithelium can be reproduced in vitro as intestinal organoids introduced a new way to understand intestinal development, homeostasis, and disease. However, organoids reflect the intestinal epithelium in isolation whereas the underlying tissue also contains myriad cell types and impressive chemical and structural complexity. This review dissects the cellular and matrix components of the intestine and discusses strategies to replicate them in vitro using principles drawing from bottom-up biological self-organization and top-down bioengineering. It also covers the cellular, biochemical and biophysical features of the intestinal microenvironment and how these can be replicated in vitro by combining strategies from organoid biology with materials science. Particularly accessible chemistries that mimic the native extracellular matrix are discussed, and bioengineering approaches that aim to overcome limitations in modelling the intestine are critically evaluated. Finally, the review considers how further advances may extend the applications of intestinal models and their suitability for clinical therapies.

Tissue niches and immunopathology through the lens of spatial tissue profiling techniques

Spatial organization plays a fundamental role in biology, influencing the function of biological structures at various levels. The immune system, in particular, relies on the orchestrated interactions of immune cells with their microenvironment to mount protective or pathogenic immune responses. The COVID-19 pandemic has underscored the significance of studying immunity within target organs to understand disease progression and severity. To achieve this, multiplex histology and spatial transcriptomics have proven indispensable in providing a spatial context to protein and gene expression patterns. By combining these techniques, researchers gain a more comprehensive understanding of the complex interactions at the cellular and molecular level in distinct tissue niches, key functional units modulating health and disease. In this review, we discuss recent advances in spatial tissue profiling techniques, highlighting their advantages over traditional histopathology studies. The insights gained from these approaches have the potential to revolutionize the diagnosis and treatment of various diseases including cancer, autoimmune disorders, and infectious diseases. However, we also acknowledge their challenges and limitations. Despite these, spatial tissue profiling offers promising opportunities to improve our understanding of how tissue niches direct regional immunity, and their relevance in tissue immunopathology, as a basis for novel therapeutic strategies and personalized medicine.

Bi-directional signaling between the intestinal epithelium and type-3 innate lymphoid cells regulates secretory dynamics and interleukin-22

Type-3 innate lymphoid cells (ILC3) respond to localized environmental cues to regulate homeostasis and orchestrate immunity in the intestine. The intestinal epithelium is an important upstream regulator and downstream target of ILC3 signaling, however, the complexity of mucosal tissues can hinder efforts to define specific interactions between these two compartments. Here, we employ a reductionist co-culture system of murine epithelial small intestinal organoids (SIO) with ILC3 to uncover bi-directional signaling mechanisms that underlie intestinal homeostasis. We report that ILC3 induce global transcriptional changes in intestinal epithelial cells, driving the enrichment of secretory goblet cell signatures. We find that SIO enriched for goblet cells promote NKp46+ ILC3 and interleukin (IL)-22 expression, which can feedback to induce IL-22-mediated epithelial transcriptional signatures. However, we show that epithelial regulation of ILC3 in this system is contact-dependent and demonstrate a role for epithelial Delta-Like-Canonical-Notch-Ligand (Dll) in driving IL-22 production by ILC3, via subset-specific Notch1-mediated activation of T-bet+ ILC3. Finally, by interfering with Notch ligand-receptor dynamics, ILC3 appear to upregulate epithelial Atoh1 to skew secretory lineage determination in SIO-ILC3 co-cultures. This research outlines two complimentary bi-directional signaling modules between the intestinal epithelium and ILC3, which may be relevant in intestinal homeostasis and disease.

The gut microbiota and its biogeography

Biogeography is the study of species distribution and diversity within an ecosystem and is at the core of how we understand ecosystem dynamics and interactions at the macroscale. In gut microbial communities, a historical reliance on bulk sequencing to probe community composition and dynamics has overlooked critical processes whereby microscale interactions affect systems-level microbiota function and the relationship with the host. In recent years, higher-resolution sequencing and novel single-cell level data have uncovered an incredible heterogeneity in microbial composition and have enabled a more nuanced spatial understanding of the gut microbiota. In an era when spatial transcriptomics and single-cell imaging and analysis have become key tools in mammalian cell and tissue biology, many of these techniques are now being applied to the microbiota. This fresh approach to intestinal biogeography has given important insights that span temporal and spatial scales, from the discovery of mucus encapsulation of the microbiota to the quantification of bacterial species throughout the gut. In this Review, we highlight emerging knowledge surrounding gut biogeography enabled by the observation and quantification of heterogeneity across multiple scales.

Bacteria-based drug delivery for treating non-oncological diseases

Bacteria inhabit all over the human body, especially the skin, gastrointestinal tract, respiratory tract, urogenital tract, as well as specific lesion sites, such as wound and tumor. By leveraging their distinctive attributes including rapid proliferation, inherent abilities to colonize various biointerfaces in vivo and produce diverse biomolecules, and the flexibility to be functionalized via genetic engineering or surface modification, bacteria have been widely developed as living therapeutic agents, showing promising potential to make a great impact on the exploration of advanced drug delivery systems. In this review, we present an overview of bacteria-based drug delivery and its applications in treating non-oncological diseases. We systematically summarize the physiological positions where living bacterial therapeutic agents can be delivered to, including the skin, gastrointestinal tract, respiratory tract, and female genital tract. We discuss the success of using bacteria-based drug delivery systems in the treatment of diseases that occur in specific locations, such as skin wound healing/infection, inflammatory bowel disease, respiratory diseases, and vaginitis. We also discuss the advantages as well as the limitations of these living therapeutics and bacteria-based drug delivery, highlighting the key points that need to be considered for further translation. This review article may provide unique insights for designing next-generation bacteria-based therapeutics and developing advanced drug delivery systems.

Circadian clock-related genome-wide mendelian randomization identifies putatively genes for ulcerative colitis and its comorbidity

BACKGROUND

Circadian rhythm is crucial to the function of the immune system. Disorders of the circadian rhythm can contribute to inflammatory diseases such as Ulcerative colitis (UC). This Mendelian Randomization (MR) analysis applies genetic tools to represent the aggregated statistical results of exposure to circadian rhythm disorders and UC and its comorbidities, allowing for causal inferences.

METHODS

Summary statistics of protein, DNA methylation and gene expression quantitative trait loci in individuals of European ancestry (pQTL, mQTL, and eQTL, respectively) were used. Genetic variants located within or near 152 circadian clock-related genes and closely related to circadian rhythm disorders were selected as instrumental variables. Causal relationships with UC and its comorbidities were then estimated through employed Summary data-based Mendelian Randomization (SMR) and Inverse-Variance-Weighted MR (IVW-MR).

RESULTS

Through preliminary SMR analysis, we identified a potential causal relationship between circadian clock-related genes and UC along with its comorbidities, which was further confirmed by IVW-MR analysis. Our study identified strong evidence of positive correlation involving seven overlapping genes (CSNK1E, OPRL1, PIWIL2, RORC, MAX, PPP5C, and AANAT) through MWAS and TWAS in UC, four overlapping genes (OPRL1, CHRNB2, FBXL17, and SIRT1) in UC with PSC, and three overlapping genes (ARNTL, USP7, and KRAS) in UC with arthropathy.

CONCLUSIONS

This SMR study demonstrates the causal effect of circadian rhythm disorders in UC and its comorbidities. Furthermore, our investigation pinpointed candidate genes that could potentially serve as drug targets.

Human intestinal organoids: Modeling gastrointestinal physiology and immunopathology - current applications and limitations

Human intestinal organoids are an ideal model system for studying gastrointestinal physiology and immunopathology. Altered physiology and mucosal immune response are hallmarks of numerous intestinal functional and inflammatory diseases, including inflammatory bowel disease (IBD), coeliac disease, irritable bowel syndrome (IBS), and obesity. These conditions impact the normal epithelial functions of the intestine, such as absorption, barrier function, secretion, and host-microbiome communication. They are accompanied by characteristic intestinal symptoms and have significant societal, economic, and healthcare burdens. To develop new treatment options, cutting-edge research is required to investigate their etiology and pathology. Human intestinal organoids derived from patient tissue recapitulate the key physiological and immunopathological aspects of these conditions, providing a promising platform for elucidating disease mechanisms. This review will summarize recent reports on patient-derived human small intestinal and colonic organoids and highlight how these models have been used to study intestinal epithelial functions in the context of inflammation, altered physiology, and immune response. Furthermore, it will elaborate on the various organoid systems in use and the techniques/assays currently available to study epithelial functions. Finally, it will conclude by discussing the limitations and future perspectives of organoid technology.

Role reversals: non-canonical roles for immune and non-immune cells in the gut

The intestine is home to an intertwined network of epithelial, immune, and neuronal cells as well as the microbiome, with implications for immunity, systemic metabolism, and behavior. While the complexity of this microenvironment has long since been acknowledged, recent technological advances have propelled our understanding to an unprecedented level. Notably, the microbiota and non-immune or structural cells have emerged as important conductors of intestinal immunity, and by contrast, cells of both the innate and adaptive immune systems have demonstrated non-canonical roles in tissue repair and metabolism. This review highlights recent works in the following two streams: non-immune cells of the intestine performing immunological functions; and traditional immune cells exhibiting non-immune functions in the gut.

Rhei Radix et Rhizoma in Xuanbai-Chengqi decoction strengthens the intestinal barrier function and promotes lung barrier repair in preventing severe viral pneumonia induced by influenza A virus

ETHNOPHARMACOLOGICAL RELEVANCE

Xuanbai-Chengqi decoction (XCD) is a traditional prescription for treating multiple organ injuries, which has been used to manage pneumonia caused by various pathogens. However, the effects of XCD on repairing pulmonary/intestinal barrier damage remain unclear, and there is a need to understand the compatibility mechanism of rhubarb.

AIM OF THE STUDY

This work aims to investigate the protective effect and mechanism of XCD on the pulmonary/intestinal barrier guided by the theory of "gut-lung concurrent treatment". Moreover, we elucidate the compatibility mechanism of rhubarb in XCD.

MATERIALS AND METHODS

An H1N1 virus-infected mouse model was adopted to investigate the reparative effects of XCD on the lung-intestinal barrier by assessing lung-intestinal permeability. Additionally, the characterization of type I alveolar epithelial cells (AT1) and type II alveolar epithelial cells (AT2) was performed to evaluate the damage to the alveolar epithelial barrier. The specific barrier-protective mechanisms of XCD were elucidated by detecting tight junction proteins and the epithelial cell repair factor IL-22. The role of rhubarb in XCD to pneumonia treatment was investigated through lung tissue transcriptome sequencing and flow cytometry.

RESULTS

XCD significantly improved lung tissue edema, inflammation, and alveolar epithelial barrier damage by regulating IL-6, IL-10, and IL-22, which, could further improve pulmonary barrier permeability when combined with the protection of alveolar epithelial cells (AT1 and AT2) as well as inhibition of H1N1 virus replication. Simultaneously, XCD significantly reduced intestinal inflammation and barrier damage by regulating IL-6, IL-1β, and tight junction protein levels (Claudin-1 and ZO-1), improving intestinal barrier permeability. The role of rhubarb in the treatment of pneumonia is clarified for the first time. In the progression of severe pneumonia, rhubarb can significantly protect the intestinal barrier, promote the repair of AT2 cells, and inhibit the accumulation of CD11b+Ly6Gvariable aberrant neutrophils by regulating the S100A8 protein.

CONCLUSION

In summary, our findings suggest that rhubarb in XCD plays a critical role in protecting intestinal barrier function and promoting lung barrier repair in preventing severe viral pneumonia caused by influenza A virus.

Cell Surface Modification-Mediated Primary Intestinal Epithelial Cell Culture Platforms for Assessing Host-Microbiota Interactions

Background: Intestinal epithelial cells (IECs) play a crucial role in regulating the symbiotic relationship between the host and the gut microbiota, thereby allowing them to modulate barrier function, mucus production, and aberrant inflammation. Despite their importance, establishing an effective ex vivo culture method for supporting the prolonged survival and function of primary IECs remains challenging. Here, we aim to develop a novel strategy to support the long-term survival and function of primary IECs in response to gut microbiota by employing mild reduction of disulfides on the IEC surface proteins with tris(2-carboxyethyl)phosphine. Methods: Recognizing the crucial role of fibroblast-IEC crosstalk, we employed a cell surface modification strategy, establishing layer-to-layer contacts between fibroblasts and IECs. This involved combining negatively charged chondroitin sulfate on cell surfaces with a positively charged chitosan thin film between cells, enabling direct intercellular transfer. Validation included assessments of cell viability, efficiency of dye transfer, and IEC function upon lipopolysaccharide (LPS) treatment. Results: Our findings revealed that the layer-by-layer co-culture platform effectively facilitates the transfer of small molecules through gap junctions, providing vital support for the viability and function of primary IECs from both the small intestine and colon for up to 5 days, as evident by the expression of E-cadherin and Villin. Upon LPS treatment, these IECs exhibited a down-regulation of Villin and tight junction genes, such as E-cadherin and Zonula Occludens-1, when compared to their nontreated counterparts. Furthermore, the transcription level of Lysozyme exhibited an increase, while Mucin 2 showed a decrease in response to LPS, indicating responsiveness to bacterial molecules. Conclusions: Our study provides a layer-by-layer-based co-culture platform to support the prolonged survival of primary IECs and their features, which is important for understanding IEC function in response to the gut microbiota.

Integration of multiple flexible electrodes for real-time detection of barrier formation with spatial resolution in a gut-on-chip system

In healthy individuals, the intestinal epithelium forms a tight barrier to prevent gut bacteria from reaching blood circulation. To study the effect of probiotics, dietary compounds and drugs on gut barrier formation and disruption, human gut epithelial and bacterial cells can be cocultured in an in vitro model called the human microbial crosstalk (HuMiX) gut-on-a-chip system. Here, we present the design, fabrication and integration of thin-film electrodes into the HuMiX platform to measure transepithelial electrical resistance (TEER) as a direct readout on barrier tightness in real-time. As various aspects of the HuMiX platform have already been set in their design, such as multiple compressible layers, uneven surfaces and nontransparent materials, a novel fabrication method was developed whereby thin-film metal electrodes were first deposited on flexible substrates and sequentially integrated with the HuMiX system via a transfer-tape approach. Moreover, to measure localized TEER along the cell culture chamber, we integrated multiple electrodes that were connected to an impedance analyzer via a multiplexer. We further developed a dynamic normalization method because the active measurement area depends on the measured TEER levels. The fabrication process and system setup can be applicable to other barrier-on-chip systems. As a proof-of-concept, we measured the barrier formation of a cancerous Caco-2 cell line in real-time, which was mapped at four spatially separated positions along the HuMiX culture area.

Sargramostim for Prophylactic Management of Gastrointestinal Immune-Related Adverse Events of Immune Checkpoint Inhibitor Therapy for Cancer

Immune checkpoint inhibitor (ICI) therapy improves outcomes in several cancers. Unfortunately, many patients experience grade 3-4 treatment-related adverse events, including gastrointestinal (GI) toxicities which are common. These GI immune-related adverse events (irAEs) induced by ICIs present significant clinical challenges, require prompt intervention, and result in treatment delays or discontinuations. The treatment for these potentially severe and even fatal GI irAEs which include enterocolitis, severe diarrhea, and hepatitis may interfere with the anti-cancer approach. Sargramostim (glycosylated, yeast-derived, recombinant human GM-CSF) is an agent that has been used in clinical practice for more than 30 years with a well-recognized safety profile and has been studied in many therapeutic areas. The mechanism of action of sargramostim may treat moderate-to-severe GI irAEs without impairing the anti-cancer therapy. Some early data also suggest a potential survival benefit. Through the differentiation/maturation of monocytes, macrophages, and neutrophils and induction of anti-inflammatory T cell responses, GM-CSF aids in GI homeostasis, mucosal healing, and mucosal immunity. GM-CSF knockout mice are susceptible to severe colitis which was prevented with murine GM-CSF administration. For some patients with GI mucosa and immune cell function impairment, e.g., Crohn's disease, sargramostim reduces disease severity. In a prospective, randomized study (ECOG 1608), advanced melanoma patients had a reduction in grade 3-5 GI irAEs and less frequent colonic perforation in the sargramostim plus ipilimumab arm compared to ipilimumab alone. Sargramostim continues to be studied with ICIs for the prophylactic management of irAEs while also potentially providing a survival benefit.

Extraction, purification, structural characteristics and biological properties of the polysaccharides from Radix Saposhnikoviae: A review

ETHNOPHARMACOLOGICAL RELEVANCE

Radix Saposhnikoviae (R. Saposhnikoviae), commonly known as FangFeng, is a renowned medicinal herb in China extensively utilized in traditional Chinese medicine. It expels pathogenic wind from the body surface, alleviates pain by removing dampness, and relieves convulsion. Therefore, it is mainly used for treating exterior syndrome, itchy wind papules, rheumatic arthralgia, and splenic asthenia-induced dampness. R. saposhnikoviae has important medicinal value, and the polysaccharide component is one of its important active ingredients.

AIM OF THE REVIEW

This review summarizes the factors influencing the content of polysaccharides in R. Saposhnikoviae (PRSs), the techniques employed for their extraction, separation, and purification, their structural characterization, and their biological activities.

MATERIALS AND METHODS

Relevant research reports on PRSs were collected from the Chinese National Knowledge Infrastructure, Web of Science, PubMed, Wanfang Data Knowledge Service Platform, China Master Theses Full-text Database, and China Doctoral Dissertations Full-text Database.

RESULTS

The content of PRSs can vary depending on cultivation methods and harvesting time. PRSs were extracted using various extraction techniques such as hot water, ultrasonic-assisted, microwave-assisted, and enzymatic extractions, as well as water extraction and alcohol precipitation. Effective purification methods involve protein removal using trifluoro-trichloroethane and the decolorization of the polysaccharide using column chromatography with D280 anion exchange resins. Current research highlights the significant pharmacological activities of PRSs in R. Saposhnikoviae, including immunomodulatory, antioxidant, anti-allergic, anti-cancer, and anti-osteoporotic effects as well as prevention of calcium loss and maintenance of mucosal function.

CONCLUSIONS

PRSs play a crucial role as bioactive constituents of R. Saposhnikoviae, exhibiting diverse biological activities and promising applications. A deeper understanding of PRSs will contribute to the improved utilization of R. Saposhnikoviae and the development of related derivatives of the active ingredients.

The Current and Promising Oral Delivery Methods for Protein- and Peptide-Based Drugs

Drugs based on peptides and proteins (PPs) have been widely used in medicine, beginning with insulin therapy in patients with diabetes mellitus over a century ago. Although the oral route of drug administration is the preferred one by the vast majority of patients and improves compliance, medications of this kind due to their specific chemical structure are typically delivered parenterally, which ensures optimal bioavailability. In order to overcome issues connected with oral absorption of PPs such as their instability depending on digestive enzymes and pH changes in the gastrointestinal (GI) system on the one hand, but also their limited permeability across physiological barriers (mucus and epithelium) on the other hand, scientists have been strenuously searching for novel delivery methods enabling peptide and protein drugs (PPDs) to be administered enterally. These include utilization of different nanoparticles, transport channels, substances enhancing permeation, chemical modifications, hydrogels, microneedles, microemulsion, proteolytic enzyme inhibitors, and cell-penetrating peptides, all of which are extensively discussed in this review. Furthermore, this article highlights oral PP therapeutics both previously used in therapy and currently available on the medical market.

Severe gut mucosal injury induces profound systemic inflammation and spleen-associated lymphoid organ response

Clinical evidence indicates a connection between gut injuries, infections, inflammation, and an increased susceptibility to systemic inflammation. Nevertheless, the animal models designed to replicate this progression are inadequate, and the fundamental mechanisms are still largely unknown. This research explores the relationship between gut injuries and systemic inflammation using a Dextran Sulfate Sodium (DSS)-induced colonic mucosal injury mouse model. Continuous treatment of adult mice with 4% DSS drinking water yielded a remarkable mortality rate by day 7, alongside intensified gut injury and detectable peripheral inflammation. Moreover, RNAscope in situ hybridization with 16S rRNA probe noted bacterial penetration into deeper colon compartments of the mice following treatment with DSS for 7 days. Histological analysis revealed inflammation in the liver and lung tissues of DSS-treated mice. In addition, we found that DSS-treated mice exhibited elevation of Alanine transaminase (ALT) and Aspartate transaminase (AST) in peripheral blood and pro-inflammatory cytokine levels in the liver. Notably, the DSS-treated mice displayed a dampened metabolic profile, reduced CD45 marker expression, and an increase in apoptosis within the lymphoid organ such as spleen. These findings suggest that high-dose DSS-induced gut injury gives rise to sepsis-like systemic inflammation characterized by multiple organ injury and profound splenocyte apoptosis and dysfunction of CD45+ cells in the spleen, indicating the role of the spleen in the pathogenesis of gut-derived systemic inflammation. Together, the severe colonic mucosal injury model facilitates research into gut damage and associated peripheral immune responses, providing a vital framework for investigating mechanisms related to clinically relevant, gut-derived systemic inflammation.

Mechanism of Iron Ion Homeostasis in Intestinal Immunity and Gut Microbiota Remodeling

Iron is a vital trace element that plays an important role in humans and other organisms. It plays an active role in the growth, development, and reproduction of bacteria, such as Bifidobacteria. Iron deficiency or excess can negatively affect bacterial hosts. Studies have reported a major role of iron in the human intestine, which is necessary for maintaining body homeostasis and intestinal barrier function. Organisms can maintain their normal activities and regulate some cancer cells in the body by regulating iron excretion and iron-dependent ferroptosis. In addition, iron can modify the interaction between hosts and microorganisms by altering their growth and virulence or by affecting the immune system of the host. Lactic acid bacteria such as Lactobacillus acidophilus (L. acidophilus), Lactobacillus rhamnosus (L. rhamnosus), and Lactobacillus casei (L. casei) were reported to increase trace elements, protect the host intestinal barrier, mitigate intestinal inflammation, and regulate immune function. This review article focuses on the two aspects of the iron and gut and generally summarizes the mechanistic role of iron ions in intestinal immunity and the remodeling of gut microbiota.

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.

Alternatives to antibiotics in pig production: looking through the lens of immunophysiology

In the livestock production system, the evolution of porcine gut microecology is consistent with the idea of "The Hygiene Hypothesis" in humans. I.e., improved hygiene conditions, reduced exposure to environmental microorganisms in early life, and frequent use of antimicrobial drugs drive immune dysregulation. Meanwhile, the overuse of antibiotics as feed additives for infectious disease prevention and animal growth induces antimicrobial resistance genes in pathogens and spreads related environmental pollutants. It justifies our attempt to review alternatives to antibiotics that can support optimal growth and improve the immunophysiological state of pigs. In the current review, we first described porcine mucosal immunity, followed by discussions of gut microbiota dynamics during the critical weaning period and the impacts brought by antibiotics usage. Evidence of in-feed additives with immuno-modulatory properties highlighting probiotics, prebiotics, and phytobiotics and their cellular and molecular networking are summarized and reviewed. It may provide insights into the immune regulatory mechanisms of antibiotic alternatives and open new avenues for health management in pig production.

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.

Mechanisms and functions of intestinal vascular specialization

The intestinal vasculature has been studied for the last 100 years, and its essential role in absorbing and distributing ingested nutrients is well known. Recently, fascinating new insights into the organization, molecular mechanisms, and functions of intestinal vessels have emerged. These include maintenance of intestinal epithelial cell function, coping with microbiota-induced inflammatory pressure, recruiting gut-specific immune cells, and crosstalk with other organs. Intestinal function is also regulated at the systemic and cellular levels, such that the postprandial hyperemic response can direct up to 30% of systemic blood to gut vessels, while micron-sized endothelial cell fenestrations are necessary for nutrient uptake. In this review, we will highlight past discoveries made about intestinal vasculature in the context of new findings of molecular mechanisms underpinning gut function. Such comprehensive understanding of the system will pave the way to breakthroughs in nutrient uptake optimization, drug delivery efficiency, and treatment of human diseases.

Cannabidiol - Help and hype in targeting mucosal diseases

Cannabidiol (CBD) is one of the most commonly utilised phytocannabinoids due to its non-psychoactive and multiple potential therapeutic properties and its non-selective pharmacology. Recent studies have demonstrated efficacy of CBD in some types of drug resistant epilepsies in combination with other therapies; comparative efficacy to other agents or placebo has been hoped for anxiety, chronic pain, and inflammatory disorders based on animal data. Although CBD products are generally treated as a restricted substance, these are being eased, partially in response to significant growth in CBD product usage and increased production but more due to emerging evidence about its safety and pharmacological properties. Currently, only one CBD product (Epidiolex®) has been approved by the Australian Therapeutic Goods Administration and US Food and Drug Administration. CBD has demonstrated promise in alleviating gut and lung diseases in vitro; however, its physicochemical properties pose a significant barrier to achieving pharmacological effects in in vivo and clinical trials. Improving CBD formulations and delivery methods using technologies including self-emulsifying emulsion, nano and micro particles could overcome these shortfalls and improve its efficacy. This review focuses on the therapeutic potential of CBD in gastrointestinal and lung diseases from the available in vitro, in vivo, and clinical research. We report on identified research gaps and obstacles in the development of CBD-based therapeutics, including novel delivery methods.

Fuzhengjiedu formula exerts protective effect against LPS-induced acute lung injury via gut-lung axis

BACKGROUND

Acute lung injury (ALI) is distinguished by rapid and severe respiratory distress and prolonged hypoxemia. A traditional Chinese medicine (TCM), known as the Fuzhengjiedu formula (FZJDF), has been shown to have anti-inflammatory benefits in both clinical and experimental studies. The precise underlying processes, nevertheless, are yet unclear.

PURPOSE

This study sought to enlighten the protective mechanism of FZJDF in ALI through the standpoint of the gut-lung crosstalk.

METHODS

The impact of FZJDF on lipopolysaccharide (LPS)-induced ALI murine model were investigated, and the lung injury score, serum interleukin-1β (IL-1β), and tumor necrosis factor-α (TNF-α) expression were measured to confirm its anti-inflammatory effects. Additionally, gut microbiota analysis and serum and fecal samples metabolomics were performed using metagenomic sequencing and high-performance liquid chromatography-quadrupole-time-of-flight mass spectrometry, respectively.

RESULTS

FZJDF significantly induced histopathological changes caused by LPS-induced ALI as well as downregulated the serum concentration of IL-1β and TNF-α. Furthermore, FZJDF had an effect in gut microbiota disturbances, and linear discriminant effect size analysis identified signal transduction, cell motility, and amino acid metabolism as the potential mechanisms of action in the FZJDF-treated group. Several metabolites in the LPS and FZJDF groups were distinguished by untargeted metabolomic analysis. Correlations were observed between the relative abundance of microbiota and metabolic products. Comprehensive network analysis revealed connections among lung damage, gut microbes, and metabolites. The expression of glycine, serine, glutamate, cysteine, and methionine in the lung and colon tissues was dysregulated in LPS-induced ALI, and FZJDF reversed these trends.

CONCLUSION

This study revealed that FZJDF considerably protected against LPS-induced ALI in mice by regulating amino acid metabolism via the gut-microbiota-lung axis and offered thorough and in-depth knowledge of the multi-system linkages of systemic illnesses.

Effects of early postnatal gastric and colonic microbiota transplantation on piglet gut health

BACKGROUND

Diarrhea is a major cause of reduced growth and mortality in piglets during the suckling and weaning periods and poses a major threat to the global pig industry. Diarrhea and gut dysbiosis may in part be prevented via improved early postnatal microbial colonization of the gut. To secure better postnatal gut colonization, we hypothesized that transplantation of colonic or gastric content from healthy donors to newborn recipients would prevent diarrhea in the recipients in the post-weaning period. Our objective was to examine the impact of transplanting colonic or gastric content on health and growth parameters and paraclinical parameters in recipient single-housed piglets exposed to a weaning transition and challenged with enterotoxigenic Escherichia coli (ETEC).

METHODS

Seventy-two 1-day-old piglets were randomized to four groups: colonic microbiota transplantation (CMT, n = 18), colonic content filtrate transplantation (CcFT, n = 18), gastric microbiota transplantation (GMT, n = 18), or saline (CON, n = 18). Inoculations were given on d 2 and 3 of life, and all piglets were milk-fed until weaning (d 20) and shortly after challenged with ETEC (d 24). We assessed growth, diarrhea prevalence, ETEC concentration, organ weight, blood parameters, small intestinal morphology and histology, gut mucosal function, and microbiota composition and diversity.

RESULTS

Episodes of diarrhea were seen in all groups during both the milk- and the solid-feeding phase, possibly due to stress associated with single housing. However, CcFT showed lower diarrhea prevalence on d 27, 28, and 29 compared to CON (all P < 0.05). CcFT also showed a lower ETEC prevalence on d 27 (P < 0.05). CMT showed a higher alpha diversity and a difference in beta diversity compared to CON (P < 0.05). Growth and other paraclinical endpoints were similar across groups.

CONCLUSION

In conclusion, only CcFT reduced ETEC-related post-weaning diarrhea. However, the protective effect was marginal, suggesting that higher doses, more effective modalities of administration, longer treatment periods, and better donor quality should be explored by future research to optimize the protective effects of transplantation.

Circular RNAs in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a term encompassing a few chronic inflammatory disorders that leads to damage of the intestinal tract. Although much progress has been made in understanding the pathology of IBD, the precise pathogenesis is not completely understood. Circular RNAs (circRNAs) are single-stranded, covalently closed, endogenous molecules in eukaryotes with a variety of biological functions. CircRNAs have been shown to have regulatory effects in many diseases, such as cancer, cardiovascular disease, and neurological disorders. CircRNAs have also been found to play important roles in IBD, and although they are not sufficiently investigated in the context of IBD, a few circRNAs have been identified as potential biomarkers for the diagnosis and prognosis of IBD and as potential therapeutic targets for IBD. Herein, we survey recent progress in understanding the functions and roles of circRNAs in IBD and discuss their potential clinical applications.

Comparative evaluation of the fecal microbiota of adult hybrid pigs and Tibetan pigs, and dynamic changes in the fecal microbiota of hybrid pigs

The breed of pig can affect the diversity and composition of fecal microbiota, but there is a lack of research on the fecal microbiota of hybrid pigs. In this study, feces samples from Chuanxiang black pigs (a hybrid of Tibetan and Duroc pigs) aged 3 days (n = 24), 70 days (n = 31), 10 months (n = 13) and 2 years (n = 30) and Tibetan pigs aged 10 months (n = 14) and 2 years (n = 15) were collected and sequenced by 16S rRNA gene sequencing technology. We also measured the weight of all the tested pigs and found that the 10-month-old and two-year-old Chuanxiang black pigs weighed about three times the weight of Tibetan pigs of the same age. After comparing the genus-level microbiota composition of Tibetan pigs and Chuanxiang black pigs at 10 months and two years of age, we found that Treponema and Streptococcus were the two most abundant bacteria in Chuanxiang black pigs, while Treponema and Chirstensenellaceae_R.7_group were the two most abundant bacteria in Tibetan pigs. Prediction of microbial community function in adult Chuanxiang black pigs and Tibetan pigs showed changes in nutrient absorption, disease resistance, and coarse feeding tolerance. In addition, we also studied the changes in fecal microbiota in Chuanxiang black pigs at 3 days, 70 days, 10 months, and 2 years of age. We found that the ecologically dominant bacteria in fecal microbiota of Chuanxiang black pigs changed across developmental stages. For example, the highest relative abundance of 70-day-old Chuanxiang black pigs at the genus level was Prevotella. We identified specific microbiota with high abundance at different ages for Chuanxiang black pigs, and revealed that the potential functions of these specific microbiota were related to the dominant phenotype such as fast growth rate and strong disease resistance. Our findings help to expand the understanding of the fecal microbiota of hybrid pigs and provide a reference for future breeding and management of hybrid pigs.

Flagellin is essential for initial attachment to mucosal surfaces by Clostridioides difficile

IMPORTANCE

Clostridioides difficile is one of the leading causes of hospital-acquired infections worldwide and presents challenges in treatment due to recurrent gastrointestinal disease after treatment with antimicrobials. The mechanisms by which C. difficile colonizes the gut represent a key gap in knowledge, including its association with host cells and mucosa. Our results show the importance of flagellin for specific adhesion to mucosal hydrogels and can help to explain prior observations of adhesive defects in flagellin and pilin mutants.

Dietary tangeretin improved antibiotic-associated diarrhea in mice by enhancing the intestinal barrier function, regulating the gut microbiota, and metabolic homeostasis

Antibiotic-associated diarrhea is mediated by antibiotic treatment and is usually caused by the disruption of the intestinal barrier, gut microbiota, and metabolic balance. To identify a dietary strategy that can mitigate the side effects of antibiotics, this study investigated the effect of tangeretin on antibiotic-associated diarrhea in C57BL/6 mice. The results revealed that dietary tangeretin significantly ameliorated symptoms of antibiotic-associated diarrhea, as evidenced by the decreased diarrhea status scores, the reduced fecal water content, the decreased caecum/body weight ratio, and the alleviated colonic tissue damage. Dietary tangeretin also exhibited a protective effect on the intestinal barrier function by upregulating the mRNA and protein expression of claudin-1 and ZO-1. Furthermore, analysis of the gut microbiota using 16S rRNA gene sequencing indicated that dietary tangeretin modulated the gut microbiota of mice with antibiotic-associated diarrhea via increasing the gut microbiota diversity and the abundance of beneficial bacteria, e.g., Lactobacillaceae and Ruminococcaceae, and decreasing the abundance of harmful bacteria, e.g., Enterococcus and Terrisporobacter. Additionally, dietary tangeretin restored the levels of short-chain fatty acids and modulated metabolic pathways by enriching purine metabolism, bile acid metabolism, ABC transporters, and choline metabolism in cancer. Collectively, these findings provide a solid scientific basis for the rational use of tangeretin as a preventive and therapeutic agent for antibiotic-associated diarrhea.

Obesity under the moonlight of c-MYC

The moonlighting protein c-Myc is a master regulator of multiple biological processes including cell proliferation, differentiation, angiogenesis, apoptosis and metabolism. It is constitutively and aberrantly expressed in more than 70% of human cancers. Overwhelming evidence suggests that c-Myc dysregulation is involved in several inflammatory, autoimmune, metabolic and other non-cancerous diseases. In this review, we addressed the role of c-Myc in obesity. Obesity is a systemic disease, accompanied by multi-organ dysfunction apart from white adipose tissue (WAT), such as the liver, the pancreas, and the intestine. c-Myc plays a big diversity of functions regulating cellular proliferation, the maturation of progenitor cells, fatty acids (FAs) metabolism, and extracellular matrix (ECM) remodeling. Moreover, c-Myc drives the expression of a wide range of metabolic genes, modulates the inflammatory response, induces insulin resistance (IR), and contributes to the regulation of intestinal dysbiosis. Altogether, c-Myc is an interesting diagnostic tool and/or therapeutic target in order to mitigate obesity and its consequences.

Metagenomic and targeted metabolomic analyses reveal distinct phenotypes of the gut microbiota in patients with colorectal cancer and type 2 diabetes mellitus

BACKGROUND

Type 2 diabetes mellitus (T2DM) is an independent risk factor for colorectal cancer (CRC), and the patients with CRC and T2DM have worse survival. The human gut microbiota (GM) is linked to the development of CRC and T2DM, respectively. However, the GM characteristics in patients with CRC and T2DM remain unclear.

METHODS

We performed fecal metagenomic and targeted metabolomics studies on 36 samples from CRC patients with T2DM (DCRC group, n = 12), CRC patients without diabetes (CRC group, n = 12), and healthy controls (Health group, n = 12). We analyzed the fecal microbiomes, characterized the composition and function based on the metagenomics of DCRC patients, and detected the short-chain fatty acids (SCFAs) and bile acids (BAs) levels in all fecal samples. Finally, we performed a correlation analysis of the differential bacteria and metabolites between different groups.

RESULTS

Compared with the CRC group, LefSe analysis showed that there is a specific GM community in DCRC group, including an increased abundance of Eggerthella , Hungatella , Peptostreptococcus , and Parvimonas , and decreased Butyricicoccus , Lactobacillus , and Paraprevotella . The metabolomics analysis results revealed that the butyric acid level was lower but the deoxycholic acid and 12-keto-lithocholic acid levels were higher in the DCRC group than other groups ( P < 0.05). The correlation analysis showed that the dominant bacterial abundance in the DCRC group ( Parvimonas , Desulfurispora , Sebaldella , and Veillonellales , among others) was negatively correlated with butyric acid, hyodeoxycholic acid, ursodeoxycholic acid, glycochenodeoxycholic acid, chenodeoxycholic acid, cholic acid and glycocholate. However, the abundance of mostly inferior bacteria was positively correlated with these metabolic acid levels, including Faecalibacterium , Thermococci , and Cellulophaga .

CONCLUSIONS

Unique fecal microbiome signatures exist in CRC patients with T2DM compared to those with non-diabetic CRC. Alterations in GM composition and SCFAs and secondary BAs levels may promote CRC development.

Catalpol ameliorates LPS-induced inflammatory response by activating AMPK/mTOR signaling pathway in rat intestinal epithelial cells

Intestinal inflammation is a common clinical intestinal disease. Catalpol, a natural iridoid compound, has been shown to have anti-inflammatory, anti-oxidant and anti-apoptotic functions, but the mechanism of its protection against intestinal inflammation is still unclear. This study investigated the protective effect and potential mechanism of catalpol on the lipopolysaccharide (LPS)-induced inflammatory response of intestinal epithelial cell-6 (IEC-6). The results showed that catalpol could inhibit LPS-induced inflammatory response by dose-dependently reducing the release of inflammatory factors, such as tumor necrosis (TNF)-α, interleukin (IL)-1β and IL-6, and inhibiting the nuclear factor kappa-B (NF-κB) signaling pathway. Catalpol ameliorated cellular oxidative stress by reducing reactive oxygen species (ROS) and malondialdehyde (MDA) levels and increasing superoxide dismutase (SOD) and glutathione peroxidase (GSH-PX) expression. Meanwhile, catalpol also inhibited cell apoptosis, decreased the expression of B-cell lymphoma 2 (Bcl-2) - associated X (Bax), caspase 3 and caspase 9, and increased the expression of Bcl-2. This study found that catalpol activates AMP-activated protein kinase (AMPK) signaling pathway and inhibit mammalian target of rapamycin (mTOR) phosphorylationthe. In a further study, after inhibiting AMPK with dorsomorphin, the anti-inflammatory effects of catalpol were significantly reduced. Therefore, catalpol ameliorates LPS-induced inflammatory response by activating AMPK/mTOR signaling pathway in IEC-6 cells.

Pathogenicity and virulence of Entamoeba histolytica, the agent of amoebiasis

The amoeba parasite Entamoeba histolytica is the causative agent of human amebiasis, an enteropathic disease affecting millions of people worldwide. This ancient protozoan is an elementary example of how parasites evolve with humans, e.g. taking advantage of multiple mechanisms to evade immune responses, interacting with microbiota for nutritional and protective needs, utilizing host resources for growth, division, and encystation. These skills of E. histolytica perpetuate the species and incidence of infection. However, in 10% of infected cases, the parasite turns into a pathogen; the host-parasite equilibrium is then disorganized, and the simple lifecycle based on two cell forms, trophozoites and cysts, becomes unbalanced. Trophozoites acquire a virulent phenotype which, when non-controlled, leads to intestinal invasion with the onset of amoebiasis symptoms. Virulent E. histolytica must cross mucus, epithelium, connective tissue and possibly blood. This highly mobile parasite faces various stresses and a powerful host immune response, with oxidative stress being a challenge for its survival. New emerging research avenues and omics technologies target gene regulation to determine human or parasitic factors activated upon infection, their role in virulence activation, and in pathogenesis; this research bears in mind that E. histolytica is a resident of the complex intestinal ecosystem. The goal is to eradicate amoebiasis from the planet, but the parasitic life of E. histolytica is ancient and complex and will likely continue to evolve with humans. Advances in these topics are summarized here.

New insight into gut microbiota-derived metabolites to enhance liver regeneration via network pharmacology study

We intended to identify favourable metabolite(s) and pharmacological mechanism(s) of gut microbiota (GM) for liver regeneration (LR) through network pharmacology. We utilized the gutMGene database to obtain metabolites of GM, and targets associated with metabolites as well as LR-related targets were identified using public databases. Furthermore, we performed a molecular docking assay on the active metabolite(s) and target(s) to verify the network pharmacological concept. We mined a total of 208 metabolites in the gutMGene database and selected 668 targets from the SEA (1,256 targets) and STP (947 targets) databases. Finally, 13 targets were identified between 61 targets and the gutMGene database (243 targets). Protein-protein interaction network analysis showed that AKT1 is a hub target correlated with 12 additional targets. In this study, we describe the potential microbe from the microbiota (E. coli), chemokine signalling pathway, AKT1 and myricetin that accelerate LR, providing scientific evidence for further clinical trials.

Interrelation of Hypoxia-Inducible Factor-1 Alpha (HIF-1 α) and the Ratio between the Mean Corpuscular Volume/Lymphocytes (MCVL) and the Cumulative Inflammatory Index (IIC) in Ulcerative Colitis

We intended to investigate the presence and medical application of serum hypoxia-inducible factor-1 alpha (HIF-1α) along with the already known systemic inflammatory markers and the new one's inflammatory indices, the proportion of mean corpuscular volume and lymphocytes (MCVL) and the cumulative inflammatory index (IIC), for patients with ulcerative colitis (UC). We sought to establish correlations that may be present between the serum levels of HIF-1α and these inflammatory indices, as well as their relationship with disease activity and the extent of UC, which can provide us with a more precise understanding of the evolution, prognosis, and future well-being of patients. Serum samples were collected from 46 patients diagnosed with UC and 23 controls. For our assessment of the serum levels of HIF-1α, we used the Enzyme-Linked Immunosorbent Assay (ELISA) technique. Thus, for HIF-1α we detected significantly higher values in more severe and more extensive UC. When it came to MCVL and IIC, we observed statistically significant differences between the three groups being compared (Severe, Moderate, and Mild). Our study highlighted that HIF-1α correlated much better with a disease activity score, MCVL, and IIC. With MCVL and IIC, a strong and very strong correlation had formed between them and well-known inflammation indices. By examining the ROC curves of the analyzed parameters, we recognized that TWI (accuracy of 83.70%) provides the best discrimination of patients with early forms of UC, followed by HIF-1α (73.90% accuracy), MCVL (70.90% accuracy), and PLR (70.40%). In our study, we observed that HIF-1α, MCVL, and PLR had the same sensitivity (73.33%) but HIF-1α had a much better specificity (60.87% vs. 58.70%, and 54.35%). Also, in addition to the PLR, HIF-1α and MCVL can be used as independent predictor factors in the discrimination of patients with early forms of UC.

Lung protection of Chimonanthus nitens Oliv. essential oil driven by the control of intestinal disorders and dysbiosis through gut-lung crosstalk

This work aimed to investigate whether Chimonanthus nitens Oliv. essential oil (CEO)-mediated lung protection was implicated in gut-lung crosstalk. Results showed that CEO attenuated lung and intestinal impairment by improving histopathological changes and inhibiting TLR4/NF-κB signaling pathway in LPS-stimulated rats, suggesting that there might be a mechanism for its lung protection involved in gut-lung interaction through manipulating the overlap in pathological changes via the similar inflammatory response. Furthermore, CEO-triggered intestinal protection was in parallel with the mitigation of ROS production, apoptosis, Ca2+ transport and mitochondrial membrane potential loss in vivo, and its intestinal protection was confirmed in vitro through IEC-6 cells. Importantly, a combination with CEO and LPS significantly remodeled gut microbiota composition compared with LPS alone in rats, while no significant impact on lung microbiota. Therefore, CEO-exerted lung protection was linked to gut and lung interactions involvement with the control of intestinal disorders and dysbiosis.

Intestine Health and Barrier Function in Fattening Rabbits Fed Bovine Colostrum

The permeability of the immature intestine is higher in newborns than in adults; a damaged gut barrier in young animals increases the susceptibility to digestive and infectious diseases later in life. It is therefore of major importance to avoid impairment of the intestinal barrier, specifically in a delicate phase of development, such as weaning. This study aimed to evaluate the effects of bovine colostrum supplementation on the intestinal barrier, such as the intestinal morphology and proliferation level and tight junctions expression (zonulin) and enteric nervous system (ENS) inflammation status (through the expression of PGP9.5 and GFAP) in fattening rabbits. Rabbits of 35 days of age were randomly divided into three groups (n = 13) based on the dietary administration: commercial feed (control group, CTR) and commercial feed supplemented with 2.5% and 5% bovine colostrum (BC1 and BC2 groups, respectively). Rabbits receiving the BC1 diet showed a tendency to have better duodenum morphology and higher proliferation rates (p < 0.001) than the control group. An evaluation of the zonulin expression showed that it was higher in the BC2 group, suggesting increased permeability, which was partially confirmed by the expression of GFAP. Our results suggest that adding 2.5% BC into the diet could be a good compromise between intestinal morphology and permeability, since rabbits fed the highest inclusion level of BC showed signs of higher intestinal permeability.

Dual function of angiogenin-4 inducing intestinal stem cells and apoptosis

The intestinal epithelium is the first line of host defense, and its homeostasis is dependent on soluble factors that comprise the crypt niche. Antimicrobial proteins are one of the mediators to maintain gut homeostasis. Angiogenin-4 (Ang4) is a member of the ribonuclease A superfamily and plays a pivotal role in antimicrobial activity against gut microbiota. However, the functions of Ang4 within the intestinal crypt niche, particularly its involvement in the development of intestinal epithelial cells (IECs), remain unknown. Here, we demonstrate that Ang4 plays a significant role in maintaining Lgr5+ intestinal stem cells (ISCs) and induces apoptosis of IECs in a concentration-dependent manner. We revealed that Ang4 is highly expressed by Paneth cells in the small intestine, as well as regenerating islet-derived family member-4 (Reg4) expressing goblet cells in the colon, and both cell subsets highly contribute to ISC maintenance. Functional analysis using intestinal organoids revealed that Ang4 induces Wnt and Notch signaling, increases Lgr5+ stem cell expansion, and promotes organoid growth. Furthermore, high concentrations of Ang4 induced apoptosis in the IEC cell line and organoids. Collectively, we propose that Ang4 is a dual functional protein and is a novel member of the crypt niche factor that promotes the expansion of ISCs and induces apoptosis.

Diet-microbiome-immune interplay in multiple sclerosis: Understanding the impact of phytoestrogen metabolizing gut bacteria

Multiple sclerosis (MS) is a chronic and progressive autoimmune disease of the central nervous system (CNS), with both genetic and environmental factors contributing to the pathobiology of the disease. Although HLA genes have emerged as the strongest genetic factor linked to MS, consensus on the environmental risk factors is lacking. Recently, the gut microbiota has garnered increasing attention as a potential environmental factor in MS, as mounting evidence suggests that individuals with MS exhibit microbial dysbiosis (changes in the gut microbiome). Thus, there has been a strong emphasis on understanding the role of the gut microbiome in the pathobiology of MS, specifically, factors regulating the gut microbiota and the mechanism(s) through which gut microbes may contribute to MS. Among all factors, diet has emerged to have the strongest influence on the composition and function of gut microbiota. As MS patients lack gut bacteria capable of metabolizing dietary phytoestrogen, we will specifically discuss the role of a phytoestrogen diet and phytoestrogen metabolizing gut bacteria in the pathobiology of MS. A better understanding of these mechanisms will help to harness the enormous potential of the gut microbiota as potential therapeutics to treat MS and other autoimmune diseases.

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.

Repairing the intestinal mucosal barrier of traditional Chinese medicine for ulcerative colitis: a review

Damage to the intestinal mucosal barrier play an important role in the pathogenesis of ulcerative colitis (UC). Discovering the key regulators and repairing the disturbed barrier are crucial for preventing and treating UC. Traditional Chinese medicine (TCM) has been proved to be effective on treating UC and has exhibited its role in repairing the intestinal mucosal barrier. We summarized the evidence of TCM against UC by protecting and repairing the physical barrier, chemical barrier, immune barrier, and biological barrier. Mechanisms of increasing intestinal epithelial cells, tight junction proteins, and mucins, promoting intestinal stem cell proliferation, restoring the abundance of the intestinal microbiota, and modulating the innate and adaptive immunity in gut, were all involved in. Some upstream proteins and signaling pathways have been elucidated. Based on the existing problems, we suggested future studies paying attention to patients' samples and animal models of UC and TCM syndromes, conducting rescue experiments, exploring more upstream regulators, and adopting new technical methods. We hope this review can provide a theoretical basis and novel ideas for clarifying the mechanisms of TCM against UC via repairing the intestinal mucosal barrier.

Extracellular Glutamine Promotes Intestinal Porcine Epithelial Cell Proliferation via Arf1-mTORC1 Pathway Independently of Rag GTPases

Glutamine (Gln) is the major energy source of intestinal porcine epithelial cells (IPEC-J2 cells) and plays a critical role in the nutritional physiological function of the intestine. However, the underlying mechanism requires further investigation. Here, the Gln-sensing pathway in IPEC-J2 cells was investigated. The results showed that Gln increased the cell proliferation. Subsequently, an analysis of the phosphorylated proteome revealed that Gln markedly upregulated ribosomal protein S6 (RPS6) phosphorylation at serine 235/236, suggesting that Gln activated the mTORC1 pathway. mTOR inhibition revealed that Gln promotes cell proliferation through the mTORC1 pathway. Similarly, blocking ADP-ribosylation factor 1 (Arf1) activity indicated that Gln-induced mTORC1 activation promoted cell proliferation in an Arf1-dependent manner. Additionally, the RagA/B pathway did not participate in Gln-induced mTORC1 activation. Collectively, these findings suggest that Gln-induced mTORC1 activation promotes IPEC-J2 cell proliferation via Arf1, not Rag GTPases. These results broaden our understanding of functional-cell-sensing amino acids, particularly Gln, that are regulated by mTORC1.

The shape of our gut: Dissecting its impact on drug absorption in a 3D bioprinted intestinal model

The small intestine is a complex organ with a characteristic architecture and a major site for drug and nutrient absorption. The three-dimensional (3D) topography organized in finger-like protrusions called villi increases surface area remarkably, granting a more efficient absorption process. The intestinal mucosa, where this process occurs, is a multilayered and multicell-type tissue barrier. In vitro intestinal models are routinely used to study different physiological and pathological processes in the gut, including compound absorption. Still, standard models are typically two-dimensional (2D) and represent only the epithelial barrier, lacking the cues offered by the 3D architecture and the stromal components present in vivo, often leading to inaccurate results. In this work, we studied the impact of the 3D architecture of the gut on drug transport using a bioprinted 3D model of the intestinal mucosa containing both the epithelial and the stromal compartments. Human intestinal fibroblasts were embedded in a previously optimized hydrogel bioink, and enterocytes and goblet cells were seeded on top to mimic the intestinal mucosa. The embedded fibroblasts thrived inside the hydrogel, remodeling the surrounding extracellular matrix. The epithelial cells fully covered the hydrogel scaffolds and formed a uniform cell layer with barrier properties close to in vivo. In particular, the villus-like model revealed overall increased permeability compared to a flat counterpart composed by the same hydrogel and cells. In addition, the efflux activity of the P-glycoprotein (P-gp) transporter was significantly reduced in the villus-like scaffold compared to a flat model, and the genetic expression of other drugs transporters was, in general, more relevant in the villus-like model. Globally, this study corroborates that the presence of the 3D architecture promotes a more physiological differentiation of the epithelial barrier, providing more accurate data on drug absorbance measurements.

Paneth cells protect intestinal stem cell niche to alleviate deoxynivalenol-induced intestinal injury

Deoxynivalenol (DON) is a common toxin in grains and feeds, and DON exposure triggers severe small intestinal injury and inflammation, which harms the health of humans and livestock. DON treatment leads to a decrease in Paneth cells, whereas the role of Paneth cells in DON-induced intestinal injury is poorly understood. We utilized dithizone (40 mg/kg) to keep murine Paneth cell number at a low level. The results showed that dithizone-mediated long-term disruption of Paneth cells aggravated intestinal injury, intestinal stem cell (ISC) loss, and microbiota disorder in DON (2 mg/kg)-treated mice. Unexpectedly, the number of goblet cells and proliferative cells was boosted in mice treated with dithizone and DON. After dithizone and DON treatments, the Firmicutes/Bacteroidetes (F/B) ratio was reduced, and the increased abundance of Dubosiella and the decreased abundance of Lactobacillus were observed in mice. The functional recovery of Paneth cells by lysozyme (200 U/day) supplementation improved intestinal injury and ISC loss in mice after DON challenge. In addition, lysozyme also promoted the growth and ISC activity of intestinal organoids. Taken together, these results demonstrate the protective role of Paneth cells in DON-induced intestinal injury. Our study raises a novel target, Paneth cell, for the treatment of DON exposure.

Poria cocos polysaccharide improves intestinal barrier function and maintains intestinal homeostasis in mice

The function of the intestinal tract is critical to human health. Poria cocos is a widely used functional edible fungus in Asia and has been reported to modulate gastrointestinal function. However, the effects of polysaccharides, the main active constituents of Poria cocos, on the intestinal tract remains unclear and is the focus of the study. Poria cocos polysaccharides (PCP) were extracted, characterized, and administered to mice by gavage. The results show that PCP used in this study has a typical polysaccharide peak with a molecular weight of 11.583 kDa and is composed primarily of mannose, D-glucosamine hydrochloride, glucose, galactose, and fucose with a molar ratio of 15.308: 0.967: 28.723: 31.631: 23.371. The methylation results suggest that the PCP backbone may be t-Gal(p), 6-Gal(p) and 2,6-Gal(p). The effects of PCP on the mucosal barrier function of the mouse intestine (duodenum, jejunum, and ileum) were examined in terms of intestinal physiological status, physical barrier, biochemical barrier, immune barrier, and microbial barrier. The results showed that PCP significantly improved the physiological state of mouse intestine. Moreover, PCP strengthened the intestinal physical barrier by upregulating the expression of intestinal Occludin and ZO-1 and downregulating the levels of serum endotoxin, DAO, D-lactate, and intestinal MPO. Regarding biochemical barrier, PCP could upregulate the expression of MUC2, β-defensin, and SIgA in intestinal tissues. In addition, PCP modulated the immune barrier by increasing IL-2, IL-4, IL-6, IL-10, TGF-β, and IFN-γ expression. Besides, PCP increased the level of SCFAs in small intestinal contents. PCP modulates intestinal barrier function by altering the microbial composition of the gut. We also found that PCP could maintain intestinal barrier function by increasing the expression of Wnt/β-Catenin and Lrp5 proteins. Generally, our findings suggested that PCP may be used as a functional food to regulate intestinal mucosal function, thereby enhancing the health of the intestinal and host.

Uncovering the Novel Role of NR1D1 in Regulating BNIP3-Mediated Mitophagy in Ulcerative Colitis

BACKGROUND

Ulcerative colitis (UC) is a chronic, incurable condition characterized by mucosal inflammation and intestinal epithelial cell (IEC) damage. The circadian clock gene NR1D1, implicated in UC and the critical mitophagy process for epithelial repair, needs further exploration regarding its role in mitophagy regulation in UC.

METHODS

We created a jet lag mouse model and induced colitis with dextran sulfate sodium (DSS), investigating NR1D1's role. Intestinal-specific Nr1d1 knockout mice were also generated. RNA sequencing, chromatin immunoprecipitation (ChIP), and dual-luciferase reporter assays helped ascertain NR1D1's regulatory effect on BNIP3 expression. The mitochondrial state in IECs was assessed through transmission electron microscopy, while confocal microscopy evaluated mitophagy-associated protein expression in colon tissue and CCD841 cells. Cell apoptosis and reactive oxygen species (ROS) were measured via flow cytometry.

RESULTS

We observed reduced NR1D1 expression in the IECs of UC patients, accentuated under jet lag and DSS exposure in mice. NR1D1 ablation led to disrupted immune homeostasis and declined mitophagy in IECs. NR1D1, usually a transcriptional repressor, was a positive regulator of BNIP3 expression, leading to impaired mitophagy, cellular inflammation, and apoptosis. Administering the NR1D1 agonist SR9009 ameliorated colitis symptoms, primarily by rectifying defective mitophagy.

CONCLUSIONS

Our results suggest that NR1D1 bridges the circadian clock and UC, controlling BNIP3-mediated mitophagy and representing a potential therapeutic target. Its agonist, SR9009, shows promise in UC symptom alleviation.

IFNγ synergies with cold atmospheric plasma in triggering colorectal cancer cell ferroptosis via the IFNγ/IFNR2/APC/TCF4/GPX4 axis

Colorectal cancer accounts for the second most common cancer-related lethality. Intestinal stem cells are responsible for enteric homeostasis maintenance that, once being transformed, become colorectal cancer stem cells. Arresting cancer stemness represents an innovative strategy for colorectal cancer management. Using intestinal stem cell organoids as the primary model, we screened common inflammatory cytokines to identify key players targeting cancer stemness. We also explored the downstream signaling that drives the functionalities of the identified cytokine through both experimental investigations and computational predictions. As the results, we identified IFNγ as the key cytokine capable of arresting intestinal stem cells via the IFNγ/IFNGR2/APC/TCF4/GPX4 axis, proposed its role in killing colorectal cancer stem cells via triggering GPX4-dependent ferroptosis, and demonstrated its synergistic anti-cancer effect with cold atmospheric plasma in killing colorectal cancer cells that is worthy to be experimentally validated.

Goblet cell-associated antigen passage: A gatekeeper of the intestinal immune system

Effective delivery of luminal antigens to the underlying immune system is the initial step in generating antigen-specific responses in the gut. However, a large body of information regarding the immune response activation process remains unknown. Recently, goblet cells (GCs) have been reported to form goblet cell-associated antigen passages (GAPs). Luminal antigens can be transported inside GAPs and reach subepithelial immune cells to induce antigen-specific immune responses, contributing largely to gut homeostasis and the prevention of some intestinal diseases like allergic enteritis and bacterial translocation. In this article, we summarized recent observations on the formation of intestinal GAPs and their roles in mucosal immunity. We hope that this review can offer a fresh perspective and valuable insights for clinicians and researchers interested in studying the intestinal immune system.

Role of mucosal immunity and epithelial-vascular barrier in modulating gut homeostasis

The intestinal mucosa represents the most extensive human barrier having a defense function against microbial and food antigens. This barrier is represented externally by a mucus layer, consisting mainly of mucins, antimicrobial peptides, and secretory immunoglobulin A (sIgA), which serves as the first interaction with the intestinal microbiota. Below is placed the epithelial monolayer, comprising enterocytes and specialized cells, such as goblet cells, Paneth cells, enterochromaffin cells, and others, each with a specific protective, endocrine, or immune function. This layer interacts with both the luminal environment and the underlying lamina propria, where mucosal immunity processes primarily take place. Specifically, the interaction between the microbiota and an intact mucosal barrier results in the activation of tolerogenic processes, mainly mediated by FOXP3+ regulatory T cells, underlying intestinal homeostasis. Conversely, the impairment of the mucosal barrier function, the alteration of the normal luminal microbiota composition (dysbiosis), or the imbalance between pro- and anti-inflammatory mucosal factors may result in inflammation and disease. Another crucial component of the intestinal barrier is the gut-vascular barrier, formed by endothelial cells, pericytes, and glial cells, which regulates the passage of molecules into the bloodstream. The aim of this review is to examine the various components of the intestinal barrier, assessing their interaction with the mucosal immune system, and focus on the immunological processes underlying homeostasis or inflammation.

Gut dysbiosis-derived β-glucuronidase promotes the development of endometriosis

OBJECTIVE

To explore the role of gut dysbiosis-derived β-glucuronidase (GUSB) in the development of endometriosis (EMs).

DESIGN

16S rRNA sequencing of stool samples from women with (n = 35) or without (n = 30) endometriosis and from a mouse model was conducted to assess gut microbiome changes and identify molecular factors influencing the development of endometriosis. Experiments in vivo in an endometriosis C57BL6 mouse model and in vitro verified the level of GUSB and its role in the development of EMs.

SETTING

Department of Obstetrics and Gynecology, The First Affiliated Hospital of Sun Yat-sen University; Guangdong Provincial Clinical Research Center for Obstetrical and Gynecological Diseases.

PATIENT(S)

Women of reproductive age with a histological diagnosis of endometriosis were enrolled in the endometriosis group (n = 35) and infertile or healthy age-matched women who had undergone a gynecological or radiological examination in the control group (n = 30). Fecal and blood samples were taken the day before surgery. Paraffin-embedded sections from 50 bowel endometriotic lesions, 50 uterosacral lesions, 50 samples without lesions, and 50 normal endometria were collected.

INTERVENTION(S)

None.

MAIN OUTCOME MEASURE(S)

Changes in the gut microbiome of patients with EMs and mice and the effect of β-glucuronidase on the proliferation and invasion of endometrial stromal cells and the development of endometriotic lesions were assessed.

RESULT(S)

No difference in α and β diversity was found between patients with EMs and controls. Immunohistochemistry analysis showed higher β-glucuronidase expression in bowel lesions and uterosacral ligament lesions than in the normal endometrium (p<0.01). β-Glucuronidase promoted the proliferation and migration of endometrial stromal cells during cell counting kit-8, Transwell, and wound-healing assays. Macrophage levels, especially M2, were higher in bowel lesions and uterosacral ligament lesions than in controls, and β-glucuronidase promoted the M0 to M2 transition. Medium conditioned by β-glucuronidase-treated macrophages promoted endometrial stromal cell proliferation and migration. β-Glucuronidase increased the number and volume of endometriotic lesions and number of macrophages present in lesions in the mouse EMs model.

CONCLUSION(S)

This β-Glucuronidase promoted EMs development directly or indirectly by causing macrophage dysfunction. The characterization of the pathogenic role of β-glucuronidase in EMs has potential therapeutic implications.