Toll-like Receptors and Inflammatory Bowel Disease

Gut virome: New key players in the pathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic inflammatory illness of the intestine. While the mechanism underlying the pathogenesis of IBD is not fully understood, it is believed that a complex combination of host immunological response, environmental exposure, particularly the gut microbiota, and genetic susceptibility represents the major determinants. The gut virome is a group of viruses found in great frequency in the gastrointestinal tract of humans. The gut virome varies greatly among individuals and is influenced by factors including lifestyle, diet, health and disease conditions, geography, and urbanization. The majority of research has focused on the significance of gut bacteria in the progression of IBD, although viral populations represent an important component of the microbiome. We conducted this review to highlight the viral communities in the gut and their expected roles in the etiopathogenesis of IBD regarding published research to date.

Targeted V-type peptide-decorated nanoparticles prevent colitis by inhibiting endosomal TLR signaling and modulating intestinal macrophage polarization

Inflammatory bowel disease (IBD) has become a serious and challenging health problem globally without curative medical treatments. Mounting evidence suggests that intestinal macrophages and their phenotypes are key players in the pathogenesis of IBD. Modulating the phenotypes and functions of intestinal macrophages through targeted interventions could be a promising approach to manage detrimental gut inflammation in IBD. In this study, we rationally design and fabricate a novel class of V-type peptide-decorated nanoparticles, VP-NP, with potent anti-inflammatory activity. Such a design allows two functional motifs FFD in a single peptide molecule to enhance the bioactivity of the nanoparticles. As expected, VP-NP exhibits a strong inhibitory activity on endosomal Toll-like receptor (TLR) signaling. Surprisingly, VP-NP can inhibit M1 polarization while facilitating M2 polarization in mouse bone marrow-derived macrophages through regulating the key transcription factors NF-κB, STAT1 and PPAR-γ. Mechanistically, VP-NP is internalized by macrophages in the endosomes, where it blocks endosomal acidification to inhibit endosomal TLR signaling; the transcriptomic analysis reveals that VP-NP potently down-regulates many genes in TLR, NF-κB, JAK-STAT, and cytokine/chemokine signaling pathways associated with inflammatory responses. In a colitis mouse model, the intraperitoneally administered VP-NP effectively alleviates the disease activities by decreasing colon inflammation and injuries, pro-inflammatory cytokine production, and myeloid cell infiltration in the gut. Furthermore, VP-NP primarily targets intestinal macrophages and alters their phenotypes from inflammatory M1-type toward the anti-inflammatory M2-type. This study provides a new nanotherapeutic strategy to specifically regulate macrophage activation and phenotypes through a dual mechanism to control gut inflammation, which may augment current clinical treatments for IBD.

PIWI-interacting RNA biomarkers in gastrointestinal disease

Detection and diagnosis of neoplastic and inflammatory gastrointestinal (GI) diseases are typically based on endoscopic and pathologic examination. In GI neoplastic diseases, diagnosis can be delayed due to the expense and invasive nature of this approach. Recently, PIWI-interacting RNAs (piRNAs), a group of small non-coding RNA molecules containing 24-31 nucleotides, have been thought to serve as biomarkers in many disease processes. For example, piRNAs are differentially expressed in GI cancer but their biologic role remains unclear. Using next-generation sequencing and microarray analyses, researchers have suggested that monitoring piRNAs could facilitate diagnosis and prognosis in GI disease. Herein, we reviewed the use of piRNAs in neoplastic, inflammatory, functional, and other diseases of the digestive system, which could shed new light on cancer screening, early detection, and personalized treatment.

EGFR and EGFRvIII coopt host defense pathways promoting progression in glioblastoma

BACKGROUND

Co-amplification of the epidermal growth factor receptor (EGFR) and EGFRvIII, a tumor-specific truncation mutant of EGFR, represent hallmark genetic lesions in glioblastoma.

METHODS

We used phospho-proteomics, RNA-sequencing, TCGA data, glioblastoma cell culture, and mouse models to study the signal transduction mediated by EGFR and EGFRvIII.

RESULTS

We report that EGFR and EGFRvIII stimulate the innate immune defense receptor Toll-like Receptor 2 (TLR2); and that knockout of TLR2 dramatically improved survival in orthotopic glioblastoma xenografts. EGFR and EGFRvIII activated TLR2 in a ligand-independent manner, promoting tumor growth and immune evasion. We show that EGFR and EGFRvIII cooperate to activate the Rho-associated protein kinase ROCK2, which modulated malignant progression both by activating TLR2 and WNT signaling, and through remodeling the tumor microenvironment.

CONCLUSIONS

Together, our findings show that EGFR and EGFRvIII cooperate to drive tumor progression through ROCK2 and downstream WNT-β-catenin/TLR2 signaling pathways.

The inflammatory bowel disease and gut microbiome are restored by employing metformin-loaded alginate-shelled microcapsules

Inflammatory bowel disease (IBD) is a chronic or recurrent inflammatory disorder affecting various parts of the gastrointestinal tract. Metformin, a widely prescribed hypoglycemic drug for type 2 diabetes, has shown potential in reducing IBD risk. However, its oral administration faces significant challenges due to the harsh gastrointestinal environment, requiring higher or more frequent doses to achieve therapeutic effects, which increases the risk of side effects. To address this, we developed alginate-shelled hydrogel microcapsules with a thin oil layer for targeted intestinal delivery of metformin. The oil layer protects metformin from gastric acid and ensures its release specifically in the intestines. In a dextran sulfate sodium-induced colitis mouse model, metformin-loaded hydrogel microcapsules (MHM) significantly reduced disease activity, intestinal epithelial damage, and macrophage infiltration linked to pro-inflammatory cytokine factors. Additionally, MHM improved dysbiosis of specific bacterial genera, including Bacteroides vulgatus, Lactobacillus (L.) gasseri, L. reuteri, and L. intestinalis, optimizing the abundance and composition of microorganisms. These findings indicate that encapsulating metformin within alginate shelled-microcapsules with a thin oil layer presents a potential delivery system for IBD treatment.

Periodontitis increases the risk of gastrointestinal dysfunction: an update on the plausible pathogenic molecular mechanisms

Periodontitis is an immuno-inflammatory disease of the soft tissues surrounding the teeth. Periodontitis is linked to many communicable and non-communicable diseases such as diabetes, cardiovascular disease, rheumatoid arthritis, and cancers. The oral-systemic link between periodontal disease and systemic diseases is attributed to the spread of inflammation, microbial products and microbes to distant organ systems. Oral bacteria reach the gut via swallowed saliva, whereby they induce gut dysbiosis and gastrointestinal dysfunctions. Some periodontal pathogens like Porphyromonas. gingivalis, Klebsiella, Helicobacter. Pylori, Streptococcus, Veillonella, Parvimonas micra, Fusobacterium nucleatum, Peptostreptococcus, Haemophilus, Aggregatibacter actinomycetomcommitans and Streptococcus mutans can withstand the unfavorable acidic, survive in the gut and result in gut dysbiosis. Gut dysbiosis increases gut inflammation, and induce dysplastic changes that lead to gut dysfunction. Various studies have linked oral bacteria, and oral-gut axis to various GIT disorders like inflammatory bowel disease, liver diseases, hepatocellular and pancreatic ductal carcinoma, ulcerative colitis, and Crohn's disease. Although the correlation between periodontitis and GIT disorders is well established, the intricate molecular mechanisms by which oral microflora induce these changes have not been discussed extensively. This review comprehensively discusses the intricate and unique molecular and immunological mechanisms by which periodontal pathogens can induce gut dysbiosis and dysfunction.

Buttermilk and Whey as Functional Foods to Ameliorate Clindamycin-Induced Changes in Mouse Intestine: Modulation of Intestinal Motility and Toll-like Receptors Expression

Antibiotic treatment is one of the main causes of intestinal dysbiosis, leading, in turn, to other intestinal alterations given the multiple relationships of the microbiota with gut health. Whey and buttermilk are two by-products from the dairy industry with numerous bioactive components. This study aimed to assess the potential of two formulas, containing a mixture of lactoferrin, milk fat globule membrane (MFGM), and whey or buttermilk, to reverse the negative effects of clindamycin on gut motility, Toll-like receptors (TLRs) expression, and oxidative stress in the intestine. For this purpose, a murine model of intestinal dysbiosis was established by clindamycin treatment. Male C57BL/6 mice were treated with saline (Control), clindamycin (Clin), a formula containing whey (F1), or buttermilk (F2) supplemented with lactoferrin and MFGM, Clin+F1, or Clin+F2. Clin delayed the whole gut transit, reduced the response to acetylcholine, decreased TLR2 expression, and increased TLR4 expression in the intestine. F1 and F2 formulas reversed the effects of Clin, restoring TLR2 receptor levels and normalizing intestinal dysmotility. These results indicate that whey- and buttermilk-based formulas supplemented with lactoferrin and MFGM could be used as functional foods to prevent or treat motility disorders and restore some components of the immune system after antibiotic treatment.

Sex-specific transcriptome similarity networks elucidate comorbidity relationships

Humans present sex-driven biological differences. Consequently, the prevalence of analyzing specific diseases and comorbidities differs between the sexes, directly impacting patients' management and treatment. Despite its relevance and the growing evidence of said differences across numerous diseases (with 4,370 PubMed results published within the past year), knowledge at the comorbidity level remains limited. In fact, to date, no study has attempted to identify the biological processes altered differently in women and men, promoting differences in comorbidities. To shed light on this problem, we analyze expression data for more than 100 diseases from public repositories, analyzing each sex independently. We calculate similarities between differential expression profiles by disease pairs and find that 13-16% of transcriptomically similar disease pairs are sex-specific. By comparing these results with epidemiological evidence, we recapitulate 53-60% of known comorbidities distinctly described for men and women, finding sex-specific transcriptomic similarities between sex-specific comorbid diseases. The analysis of shared underlying pathways shows that diseases can co-occur in men and women by altering alternative biological processes. Finally, we identify different drugs differentially associated with comorbid diseases depending on patients' sex, highlighting the need to consider this relevant variable in the administration of drugs due to their possible influence on comorbidities.

Curcumin attenuates ulcerative colitis via regulation of Sphingosine kinases 1/NF-κB signaling pathway

Curcumin, a compound from Curcuma longa L., has significant anti-inflammatory properties. However, the mechanisms underlying its anti-inflammatory activity in dextran sodium sulfate (DSS)-induced ulcerative colitis (UC) remain inadequately understood. This study aimed to further elucidate the molecular mechanisms of curcumin DSS-induced UC mice. Our data showed that curcumin alleviated DSS-induced colitis by reducing intestinal damage and inflammation, increasing goblet cells in colon tissues. Enzyme-linked immunosorbent assay revealed that curcumin reduced the expression of inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1β, and interleukin-8) in serum and myeloperoxidase in colon tissues. A comprehensive analysis integrating network pharmacology and RNA sequencing (RNA-seq) revealed significant enrichment of the nuclear factor kappa B (NF-κB) signaling pathways. Notably, RNA-seq analysis demonstrated that curcumin significantly downregulated the mRNA expression of sphingosine kinase 1 (SphK1). Furthermore, molecular docking analysis showed that curcumin can bind to SphK1 and NF-κB. Additionally, curcumin was found to inhibit the activation of the SphK1/NF-κB signaling pathway in DSS-induced UC colon tissue. This study addresses pharmacologic and mechanistic perspectives of curcumin that ameliorates DSS-induced UC and inflammatory response.

Curcumin Regulates Microglia Polarization to Alleviate Ischemic Stroke by Targeting microRNA-205-5p/Kruppel-Like Factor 2 (KLF2)/Activating Transcription Factor 2 (ATF2) Axis

Ischemic stroke (IS) often causes fearful sequela, even death. Curcumin was beneficial to IS, but its underlying molecular mechanism is unclear. Mice were subjected to middle cerebral artery occlusion (MCAO) surgery, and BV-2 cells were treated with oxygen-glucose deprivation/reoxygenation (OGD/R) induction to establish IS models in vivo and in vitro. Abundance of genes and proteins was determined using quantitative real-time polymerase chain reaction (RT-qPCR), immunofluorescence (IF), and western blot. Interleukin-1β (IL-1β), interleukin-6 (IL-6), and interleukin-10 (IL-10) levels were analyzed using enzyme-linked immunosorbent assay (ELISA). Modified neurological severity score (mNSS), corner test, foot fault test, adhesive removal test, and 2,3,5-triphenyltetrazolium chloride (TTC) staining were applied to evaluate the brain injury of mice. The correlation between miR-205-5p and Kruppel-like factor 2 (KLF2) was affirmed using dual luciferase reporter assay. Our results revealed that curcumin alleviated brain damage in MCAO mice through driving microglia M2 polarization. Of note, curcumin resulted in decreased miR-205-5p expression in MCAO mice. miR-205-5p knockdown resulted in promoted microglia M2 polarization in OGD/R conditions and achieved similar results to curcumin treatment in MCAO mice. Moreover, curcumin played a promoting role in microglia M2 polarization under OGD/R conditions, while miR-205-5p overexpression or KLF2 knockdown abolished these effects. On the mechanism, miR-205-5p was a target of curcumin, and miR-205-5p further interacted with KLF2 to inhibit activating transcription factor 2 (ATF2) expression. miR-205-5p, decreased by curcumin, suppressed microglia M2 polarization to worsen IS injury through the mediating KLF2/ATF2 axis.

Oligomerization of 33-mer Gliadin Peptides: Supramolecular Assemblies in Celiac Disease

The 33-mer gliadin peptide and its deamidated derivative, known as 33-mer DGP, are proteolytically resistant peptides central to the pathomechanism of celiac disease (CeD), the autoimmune presentation of gluten-related disorders (GRD). Both peptides can form spontaneous oligomers in the nanomolar concentration, leading to the formation of nanostructures. In other protein-related diseases, oligomers and aggregates are central in their pathomechanism; therefore, it was hypothesized that the oligomerization of proteolytical-resistant 33-mer gliadin peptides could be an underrecognized disease trigger. This review focuses on the current understanding of 33-mer peptides and their oligomers in vitro and cellular experiments. We intend to give the necessary details that incentivize the chemistry community to get involved in the effort to understand the self-assembly of gliadin peptides and the role of their supramolecular structures in CeD and the other GRD. More research is needed to design effective and safe chemical and/or nutritional interventions beyond the gluten-free diet.

The biochemical effects of carotenoids in orange carrots on the colonic proteome in a mouse model of diet-induced obesity

Introduction

Carotenoids are naturally occurring pigments in plants and are responsible for the orange, yellow, and red color of fruits and vegetables. Carrots are one of the primary dietary sources of carotenoids. The biological activities of carotenoids in higher organisms, including their immunomodulatory activities, are well documented in most tissues but not the large intestine. The gastrointestinal barrier acts as a line of defense against the systemic invasion of pathogenic bacteria, especially at the colonic level.

Methods

To test whether carotenoids in orange carrots can alleviate obesity-associated gut inflammation and strengthen the intestinal barrier function, male C57BL/6J mice were randomized to one of four experimental diets for 20 weeks (n = 20 animals/group): Low-fat diet (LFD, 10% calories from fat), high-fat diet (HFD, 45% calories from fat), HFD with white carrot powder (HFD+WC), or HFD with orange carrot powder (HFD + OC). Colon tissues were harvested to analyze the biochemical effects of carotenoids in carrots. The distal sections were subjected to isobaric labeling-based quantitative proteomics in which tryptic peptides were labeled with tandem mass tags, followed by fractionation and LC-MS/MS analysis in an Orbitrap Eclipse Tribrid instrument.

Results

High-performance liquid chromatography results revealed that the HFD+WC pellets were carotenoid-deficient, and the HFD+OC pellets contained high concentrations of provitamin A carotenoids, specifically α-carotene and β-carotene. As a result of the quantitative proteomics, a total of 4410 differentially expressed proteins were identified. Intestinal barrier-associated proteins were highly upregulated in the HFD+OC group, particularly mucin-2 (MUC-2). Upon closer investigation into mucosal activity, other proteins related to MUC-2 functionality and tight junction management were upregulated by the HFD+OC dietary intervention.

Discussion

Collectively, our findings suggest that carotenoid-rich foods can prevent high-fat diet-induced intestinal barrier disruption by promoting colonic mucus synthesis and secretion in mammalian organisms. Data are available via ProteomeXchange with identifier PXD054150.

A New Probiotic Formulation Promotes Resolution of Inflammation in a Crohn's Disease Mouse Model by Inducing Apoptosis in Mucosal Innate Immune Cells

The interaction between gut-residing microorganisms plays a critical role in the pathogenesis of Crohn's disease (CD), where microbiome dysregulation can alter immune responses, leading to unresolved local inflammation. The aim of this study is to analyze the immunomodulatory properties of a recently developed probiotic + amylase blend in the SAMP1/YitFc (SAMP) mouse model of CD-like ileitis. Four groups of SAMP mice were gavaged for 56 days with the following treatments: 1) probiotic strains + amylase (0.25 mg/100 µL PBS); 2) only probiotics; 3) only amylase; PBS-treated controls. Ilea were collected for GeoMx Digital Spatial Profiler (DSP) analysis and histological evaluation. Histology assessment for inflammation indicated a significantly reduced level of ileitis in mice administered the probiotics + amylase blend. DSP analysis showed decreased abundance of neutrophils and increased abundance of dendritic cells, regulatory T cells, and macrophages, with a significant enrichment of five intracellular pathways related to apoptosis, in probiotics + amylase-treated mice. Increased apoptosis occurrence was confirmed by (TdT)- deoxyuridine triphosphate (dUTP)-biotin nick end labeling assay. Our data demonstrate a beneficial role of the probiotic and amylase blend, highlighting an increased apoptosis of innate immunity-associated cell subsets, thus promoting the resolution of inflammation. Hence, we suggest that the developed probiotic enzyme blend may be a therapeutic tool to manage CD and therefore is a candidate formulation to be tested in clinical trials.

Improving curcumin bioavailability: Targeted delivery of curcumin and loading systems in intestinal inflammation

Curcumin is a natural food ingredient and has the potential to alleviate inflammation and combat cancer. The incidence of intestinal inflammation has been increasing and poses a severe risk to human health. Due to low absorption and bioavailability, curcumin's anti-inflammatory ability is ineffective. To improve the bioavailability of curcumin, descriptions of the intestinal barrier, signaling pathways, and transport mechanisms are reviewed. Blocking the signaling pathways lowers the number of inflammatory cytokines produced, which is the primary mechanism by which curcumin relieves inflammatory symptoms. The bioavailability of curcumin is not only related to physicochemical properties but also to the nature of the carrier material. Environmental indicators also have an impact on the improvement of curcumin bioavailability in applications. There is a need to develop multifunctional and more stable nanomaterial targeting systems to improve curcumin bioavailability and achieve better results in nanotechnology research and targeted inflammation therapy.

Exploring the therapeutic potential of polysaccharide from Portulaca oleracea L.: A review of phytochemistry and immunomodulatory effect

Portulaca oleracea L., a plant with both edible and medicinal properties, is traditionally valued for its diuretic, antipyretic, antiseptic, antispasmodic, and anthelmintic functions in folk medicine. P. oleracea polysaccharide (POP), a pivotal bioactive component, has various biological activities. Notably, their immunomodulatory capabilities have emerged as a significant area of research. The extraction, purification, monosaccharide composition, structure characterization, and biological activity of POP have been extensively investigated to identify the active components and to clarify their pharmacological actions and underlying molecular mechanisms. It aims to delineate the pharmacological mechanisms and molecular pathways associated with these polysaccharides, thereby underscoring their therapeutic promise and nutritional significance. Furthermore, the review critically examines the current research landscape of POP, identifying gaps and proposing innovative perspectives to enrich the scientific discourse surrounding these bioactive compounds.

Use of Caenorhabditis elegans to Unravel the Tripartite Interaction of Kynurenine Pathway, UPRmt and Microbiome in Parkinson's Disease

The model organism Caenorhabditis elegans and its relationship with the gut microbiome are gaining traction, especially for the study of neurodegenerative diseases such as Parkinson's Disease (PD). Gut microbes are known to be able to alter kynurenine metabolites in the host, directly influencing innate immunity in C. elegans. While the mitochondrial unfolded protein response (UPRmt) was first characterized in C. elegans in 2007, its relevance in host-microbiome interactions has only become apparent in recent years. In this review, we provide novel insights into the current understanding of the microbiome-gut-brain axis with a focus on tripartite interactions between the UPRmt, kynurenine pathway, and microbiome in C. elegans, and explore their relationships for PD remediations.

Layer by layer self-assembled hyaluronic acid nanoarmor for the treatment of ulcerative colitis

Natural compound-based treatments provide innovative ways for ulcerative colitis therapy. However, poor targeting and rapid degradation curtail its application, which needs to be addressed. Inspired by biomacromolecule-based materials, we have developed an orally administrated nanoparticle (GBP@HA NPs) using bovine serum albumin as a carrier for polyphenol delivery. The system synergizes galactosylated bovine serum albumin with two polyphenols, epigallocatechin gallate and tannic acid, which is then encased in "nanoarmor" of ε-Polylysine and hyaluronic acid to boost its stability and targeting. Remarkably, the nanoarmor demonstrated profound therapeutic effects in both acute and chronic mouse models of ulcerative colitis, mitigating disease symptoms via multiple mechanisms, regulating inflammation related factors and exerting a modulatory impact on gut microbiota. Further mechanistic investigations indicate that GBP@HA NPs may act through several pathways, including modulation of Keap1-Nrf2 and NF-κB signaling, as well as Caspase-1-dependent pyroptosis. Consequently, this novel armored nanotherapy promotes the way for enhanced polyphenol utilization in ulcerative colitis treatment research.

Nociplastic pain mechanisms and toll-like receptors as promising targets for its management

ABSTRACT

Nociplastic pain, characterized by abnormal pain processing without an identifiable organic cause, affects a significant portion of the global population. Unfortunately, current pharmacological treatments for this condition often prove ineffective, prompting the need to explore new potential targets for inducing analgesic effects in patients with nociplastic pain. In this context, toll-like receptors (TLRs), known for their role in the immune response to infections, represent promising opportunities for pharmacological intervention because they play a relevant role in both the development and maintenance of pain. Although TLRs have been extensively studied in neuropathic and inflammatory pain, their specific contributions to nociplastic pain remain less clear, demanding further investigation. This review consolidates current evidence on the connection between TLRs and nociplastic pain, with a specific focus on prevalent conditions like fibromyalgia, stress-induced pain, sleep deprivation-related pain, and irritable bowel syndrome. In addition, we explore the association between nociplastic pain and psychiatric comorbidities, proposing that modulating TLRs can potentially alleviate both pain syndromes and related psychiatric disorders. Finally, we discuss the potential sex differences in TLR signaling, considering the higher prevalence of nociplastic pain among women. Altogether, this review aims to shed light on nociplastic pain, its underlying mechanisms, and its intriguing relationship with TLR signaling pathways, ultimately framing the potential therapeutic role of TLRs in addressing this challenging condition.

A Family of Cyclic Lipopeptides Found in Human Isolates of Bacillus Ameliorates Acute Colitis via Direct Agonism of Toll-Like Receptor 2 in a Murine Model of Inflammatory Bowel Disease

BACKGROUND

The Bacillus-derived cyclic lipopeptides (surfactin, iturin, and fengycin) form potent Heterogeneous Lipopeptide Micelle (HeLM) complexes. HeLM is a small molecule that has been shown to have immunomodulatory effects. However, how HeLM regulates inflammation is not clear, moreover its application to Inflammatory Bowel Disease (IBD), specifically Ulcerative Colitis (UC), has not been tested before.

AIMS

To use a murine model of IBD and determine the effects of HeLM and related molecular mechanisms of action.

METHODS

Colitis was induced in mice by administration of 4% Dextran Sodium Sulfate. Three preparations were tested against negative and positive controls: Purified HeLM, the wild-type strain that produces it, and an isogenic mutant that does not produce HeLM. Clinical, biochemical, and histological scoring systems were used to assess the severity of colitis. RT-qPCR and cell cultures were used to determine the levels of molecular signaling. Fecal samples were processed for metagenomic analysis.

RESULTS

Purified HeLM, and the wild-type strain, significantly decreased the severity of colitis as determined by the disease activity index (DAI), mouse colitis histology index (MCHI), fecal calprotectin, and colonic length. This effect was not seen in the mutant. HeLM was found to be an agonist to TLR-2, seemingly activating the Toll-Like Receptor 2/IL-10 pathway, with subsequent downregulation of inflammatory cytokines (TNF-α, IL-1β, and IL-6). At higher concentrations HeLM inhibited lipopolysaccharide ligands from activating TLR-4. The reduction in colitis was not due to microbiome modulation, as had previously been hypothesized.

CONCLUSION

Our results indicate that HeLM ameliorates colitis by TLR-2-induced IL-10 production and possibly via the inhibition of lipopolysaccharide.

Controlling Candida: immune regulation of commensal fungi in the gut

The intestinal microbiome harbors fungi that pose a significant risk to human health as opportunistic pathogens and drivers of inflammation. Inflammatory and autoimmune diseases are associated with dysbiotic fungal communities and the expansion of potentially pathogenic fungi. The gut is also the main reservoir for disseminated fungal infections. Immune interactions are critical for preventing commensal fungi from becoming pathogenic. Significant strides have been made in defining innate and adaptive immune pathways that regulate intestinal fungi, and these discoveries have coincided with advancements in our understanding of the fungal molecular pathways and effectors involved in both commensal colonization and pathogenesis within the gut. In this review, we will discuss immune interactions important for regulating commensal fungi, with a focus on how specific cell types and effectors interact with fungi to limit their colonization or pathogenic potential. This will include how innate and adaptive immune pathways target fungi and orchestrate antifungal immune responses, in addition to how secreted immune effectors, such as mucus and antimicrobial peptides, regulate fungal colonization and inhibit pathogenic potential. These immune interactions will be framed around our current understanding of the fungal effectors and pathways regulating colonization and pathogenesis within this niche. Finally, we highlight important unexplored mechanisms by which the immune system regulates commensal fungi in the gut.

Network pharmacology integrated with molecular docking and molecular dynamics simulations to explore the mechanism of Tongxie Yaofang in the treatment of ulcerative colitis

Tongxie Yaofang (TXYF), a classical traditional Chinese medicine, is commonly used in China to treat ulcerative colitis (UC). The aim of this study was to integrate network pharmacology with molecular docking and molecular dynamics simulations to explore the mechanism of Tongxie Yaofang in the treatment of UC. The traditional Chinese medicine systems pharmacology database was used to retrieve the relevant chemical compositions of the herbs contained in TXYF. The DisGeNET, GeneCards, Online Mendelian Inheritance in Man, and Therapeutic Target Database databases were used to retrieve UC-related targets. To construct protein-protein interaction networks and screen for key targets, gene ontology and Kyoto Encyclopedia of Genes and Genomes analyses of the key targets of TXYF in the treatment of UC were performed using R 4.3.2 software. AutoDock Tools 1.5.7 was used for molecular docking. Molecular dynamics simulations of protein complexes and complexes of proteins with small-molecule ligands and eutectic ligands were carried out with Gromacs 2022 software. Network pharmacology analysis revealed that TXYF could act on UC through multiple targets and pathways. It may exert therapeutic effects mainly through the AGE/RAGE, TOLL, JAK/STAT, and Th17 signaling pathways. The possible targets of TXYF in the treatment of UC could be AKT1, BCL2, EGFR, HMOX1, HSP90AA1, and TGFβ1. Molecular docking analysis revealed that AKT1 had the highest binding energy (-10.55 kcal/mol). Molecular dynamics simulations revealed that the complexes formed by the AKT1 protein and the chemical compounds MOL001910 and MOL00035 had good stability and high binding strength. AKT1 may be the most critical target of TXYF in treating UC, and the key chemical components of TXYF in treating UC may include β-sitosterol (MOL000358) and 11alpha,12alpha-epoxy-3beta-23-dihydroxy-30-norolean-20-en-28,12beta-olide (MOL00 1910). This study revealed that TXYF may exert therapeutic effects on UC through multiple targets, multiple biological functions, and multiple signaling pathways. This study provides a new insight into the pharmacological mechanism of TXYF in treating UC.

The Contribution of Genetic and Epigenetic Factors: An Emerging Concept in the Assessment and Prognosis of Inflammatory Bowel Diseases

Inflammatory bowel disease (IBD) represents heterogeneous and relapsing intestinal conditions with a severe impact on the quality of life of individuals and a continuously increasing prevalence. In recent years, the development of sequencing technology has provided new means of exploring the complex pathogenesis of IBD. An ideal solution is represented by the approach of precision medicine that investigates multiple cellular and molecular interactions, which are tools that perform a holistic, systematic, and impartial analysis of the genomic, transcriptomic, proteomic, metabolomic, and microbiomics sets. Hence, it has led to the orientation of current research towards the identification of new biomarkers that could be successfully used in the management of IBD patients. Multi-omics explores the dimension of variation in the characteristics of these diseases, offering the advantage of understanding the cellular and molecular mechanisms that affect intestinal homeostasis for a much better prediction of disease development and choice of treatment. This review focuses on the progress made in the field of prognostic and predictive biomarkers, highlighting the limitations, challenges, and also the opportunities associated with the application of genomics and epigenomics technologies in clinical practice.

Prospective therapeutic targets and recent advancements in the treatment of inflammatory bowel disease

OBJECTIVE

Inflammatory Bowel Disease (IBD) poses a persistent challenge in the realm of gastroenterology, necessitating continual exploration of innovative treatment strategies. The limited efficacy and potential side effects associated with existing therapeutic modalities underscore the urgent need for novel approaches in IBD management. This study aims to examine potential therapeutic targets and recent advancements in understanding the disease's intricate pathogenesis, with a spotlight on the gut microbiome, immune dysregulation, and genetic predispositions.

METHODS

A comprehensive review was conducted to delve into the pressing demand for new avenues in IBD treatment. The study examined potential therapeutic targets such as phosphodiesterase 4 (PDE4) inhibitors, immune system modulators, Tyrosine kinase receptors (TYK), Toll-like receptors (TLRs), modulation of the gut microbiota, stem cell therapy, fibrosis management, interleukins (ILs) regulation, and oxidative stress mitigation. Additionally, advances in precision medicine, biologics, small molecule inhibitors, and microbiome modulation techniques were explored.

RESULTS

The investigation unveiled promising therapeutic targets and provided insights into recent breakthroughs that herald a transformative era in the therapeutic landscape for IBD. Advances in precision medicine, biologics, small molecule inhibitors, and the exploration of microbiome modulation techniques stood out as pivotal milestones in the field of gastroenterology.

CONCLUSIONS

The findings offer renewed hope for enhanced efficacy, reduced side effects, and improved patient outcomes in the treatment of IBD. These innovative approaches necessitate continual exploration and underscore the urgent need for novel strategies in IBD management, potentially revolutionizing the realm of gastroenterology.

Eosinophils, Eosinophilic Gastrointestinal Diseases, and Inflammatory Bowel Disease: A Critical Review

BACKGROUND/OBJECTIVES

Inflammatory bowel disease (IBD) and eosinophilic gastrointestinal diseases (EGIDs) are complex, multifactorial chronic inflammatory disorders affecting the gastrointestinal tract. Their epidemiology, particularly for eosinophilic esophagitis (EoE), is increasing worldwide, with a rise in the co-diagnosis of IBD and EGIDs. Both disorders share common risk factors, such as early exposure to antibiotics or specific dietary habits. Moreover, from a molecular perspective, eosinophilic infiltration is crucial in the diagnosis of eosinophilic disorders, and it also plays a pivotal role in IBD histological diagnosis. Indeed, recent evidence highlights the significant role of eosinophils in the health of the intestinal mucosal barrier and as mediators between innate and acquired immunity, even indicating a potential role in IBD pathogenesis. This narrative review aims to summarize the current evidence regarding the common clinical and molecular aspects of EGIDs and IBD and the current state of knowledge regarding overlap conditions and their pathogenesis.

METHODS

Pubmed was searched until May 2023 to assess relevant studies describing the epidemiology, pathophysiology, and therapy of EGIDs in IBD.

RESULTS

The immune pathways and mechanisms underlying both EGIDs and IBD remain partially known. An improved understanding of the role of eosinophils in overlapping conditions could lead to enhanced diagnostic precision, the development of more effective future therapeutic strategies, and a more accurate prediction of patient response. Consequently, the identification of red flags indicative of an eosinophilic disorder in IBD patients is of paramount importance and must be evaluated on a case-by-case basis.

Effect of knocking out mouse Slc44a4 on colonic uptake of the microbiota-generated thiamine pyrophosphate and colon physiology

Humans and mammals obtain vitamin B1 from dietary and gut microbiota sources. A considerable amount of the microbiota-generated vitamin exists in the form of thiamine pyrophosphate (TPP), and colonocytes are capable of absorbing TPP via a specific carrier-mediated process that involves the colonic TPP transporter (cTPPT encoded by SLC44A4). Little is known about the relative contribution of the SLC44A4 transporter toward total colonic carrier-mediated TPP uptake and its role in colon physiology. To address these issues, we generated an Slc44a4 knockout (KO) mouse model (by Cre-Lox recombination) and found a near-complete inhibition in colonic carrier-mediated [3H]TPP uptake in the Slc44a4 KO compared with wild-type (WT) littermates. We also observed a significant reduction in KO mice's body weight and a shortening of their colon compared with WT. Using RNAseq and Ingenuity pathway analysis (IPA) approaches, we found that knocking out the colonic Slc44a4 led to changes in the level of expression of many genes, including upregulation in those associated with intestinal inflammation and colitis. Finally, we found that the Slc44a4 KO mice were more susceptible to the effect of the colitogenic dextran sodium sulfate (DSS) compared with WT animals, a finding that lends support to the recent prediction by multiple genome-wide association studies (GWAS) that SLC44A4 is a possible colitis susceptibility gene. In summary, the results of these investigations show that Slc44a4 is the predominant or only transporter involved in the colonic uptake of TPP, that the transporter is important for colon physiology, and that its deletion increases susceptibility to inflammation.NEW & NOTEWORTHY This study shows that Slc44a4 is the predominant or only transport system involved in the uptake of the gut microbiota-generated thiamine pyrophosphate (TPP) in the colon and that its deletion affects colon physiology and increases its susceptibility to inflammation.

Toll-like receptor-8 mRNA expression as a predictor of enterocolitis in hirschsprung disease: a cross-sectional study

Introduction:

Hirschsprung-associated enterocolitis (HAEC) is an inflammatory intestinal condition occurring in patients with Hirschsprung disease (HD). While the exact pathogenesis remains unclear, factors such as intestinal mucosal barrier injury, abnormal immune responses, and pathogenic infections contribute to HAEC. Toll-like receptors (TLRs) 7 and 8 are key in viral recognition and correlate with intestinal mucosal inflammation. In particular, TLR-8 contributes to antiviral responses, and chronic inflammation, and can be targeted with adjuvants. This study investigates the relationship between TLR-8 mRNA expression and enterocolitis in HD.

Methods:

This cross-sectional study utilized simple random sampling. Histopathological analysis of colon samples from HD patients was used to assess enterocolitis severity, and RT-PCR quantified TLR-8 mRNA expression. HD diagnosis was confirmed via rectal biopsy, and enterocolitis was graded using Teitelbaum’s classification.

Results:

The study included 29 patients with an average age of 4.8 years. TLR-8 mRNA expression averaged 8.5 (fold change), ranging from 6.5 to 13.8. Subjects were divided into low (≤8.1) and high (>8.1) expression groups, with 15 (51.7%) and 14 (48.3%) patients, respectively. Enterocolitis severity distribution was 22 (75.9%) normal, 1 (3.4%) grade II, 4 (13.8%) grade III, and 2 (6.9%) IV.

Conclusion:

There is a significant association between TLR-8 mRNA expression and the incidence of enterocolitis in patients with HD. The authors found that increased TLR-8 mRNA expression in HD patients resulted in a twofold higher risk of enterocolitis. Altogether, our data indicates the potential for TLR-8 mRNA expression in biopsies as an indicator of the risk of enterocolitis development in patients with HD.

Moringin alleviates DSS-induced ulcerative colitis in mice by regulating Nrf2/NF-κB pathway and PI3K/AKT/mTOR pathway

Ulcerative colitis (UC) is a main form of inflammatory bowel disease (IBD), which is a chronic and immune-mediated inflammatory disease. Moringin (MOR) is an isothiocyanate isolated from Moringa oleifera Lam., and has been recognized as a promising potent drug for inflammatory diseases and antibacterial infections. The present study investigated the role of moringin in dextran sulfate sodium (DSS)-induced UC mice. Mouse colitis was induced by adding DSS to the drinking water for seven consecutive days. Our experimental results showed that MOR relieves DSS-induced UC in mice by increasing body weight and colonic length, and reducing the disease activity index and histological injury. Mechanistically, MOR improves intestinal barrier function by increasing the expression of tight junction proteins (TJPs) and enhancing the secretion of mucin in DSS-induced mice. MOR inhibits inflammatory response and intestinal damage by regulating Nrf2/NF-κB signaling pathway and modulating the PI3K/AKT/mTOR pathway. Furthermore, in Nrf2 knockout (Nrf2-/-) mice, the protective effects of MOR on DSS-induced UC were abolished. Meanwhile, treatment with MOR reduced inflammation and cell damage via regulating Nrf2/NF-κB pathway in a lipopolysaccharide (LPS)-induced inflammation model of Caco-2 cells. In contrast, ML385, an Nrf2 inhibitor, might eliminate the protection provided by MOR. Notably, treatment with MOR significantly up-regulated the expression of peroxisome proliferator-activated receptor-γ (PPAR-γ), suggesting that MOR may be a potential PPAR-γ activator. In conclusion, MOR exerts protective effect in UC by improving intestinal barrier function, regulating Nrf2/NF-κB and PI3K/AKT/mTOR signaling pathways, and another effect associated with the regulation of PPAR-γ expression.

Suppression of MyD88 disturbs gut microbiota and activates the NLR pathway and hence fails to ameliorate DSS-induced colitis

Background

Myeloid differentiation factor 88 (MyD88) is the core adaptor for Toll-like receptors defending against microbial invasion and initiating a downstream immune response during microbiota-host interaction. However, the role of MyD88 in the pathogenesis of inflammatory bowel disease is controversial. This study aims to investigate the impact of MyD88 on intestinal inflammation and the underlying mechanism.

Methods

MyD88 knockout (MyD88-/-) mice and the MyD88 inhibitor (TJ-M2010-5) were used to investigate the impact of MyD88 on acute dextran sodium sulfate (DSS)-induced colitis. Disease activity index, colon length, histological score, and inflammatory cytokines were examined to evaluate the severity of colitis. RNA transcriptome analysis and 16S rDNA sequencing were used to detect the potential mechanism.

Results

In an acute DSS-colitis model, the severity of colitis was not alleviated in MyD88-/- mice and TJ-M2010-5-treated mice, despite significantly lower levels of NF-κB activation being exhibited compared to control mice. Meanwhile, 16S rDNA sequencing and RNA transcriptome analysis revealed a higher abundance of intestinal Proteobacteria and an up-regulation of the nucleotide oligomerization domain-like receptors (NLRs) signaling pathway in colitis mice following MyD88 suppression. Further blockade of the NLRs signaling pathway or elimination of gut microbiota with broad-spectrum antibiotics in DSS-induced colitis mice treated with TJ-M2010-5 ameliorated the disease severity, which was not improved solely by MyD88 inhibition. After treatment with broad-spectrum antibiotics, downregulation of the NLR signaling pathway was observed.

Conclusion

Our study suggests that the suppression of MyD88 might be associated with unfavorable changes in the composition of gut microbiota, leading to NLR-mediated immune activation and intestinal inflammation.

The association between circulating leukocytes and inflammatory bowel disease: a two-sample Mendelian randomization study

Background

Inflammatory bowel disease (IBD) is a highly prevalent, recurrent, chronic intestinal inflammatory disease. Several observational studies have shown that circulating leukocytes are strongly associated with IBD. However, whether alterations in leukocytes are causally related to IBD remains uncertain. The present study explores this issue with the Mendelian randomization (MR) analysis method.

Methods

The Genome wide association study (GWAS) statistical data related to circulating leukocytes and IBD were obtained from the Blood Cell Consortium and the IEU Qpen GWAS project, respectively. Inverse variance weighting (IVW) was used as the main MR analytical method, coupled with a series of sensitivity analyses to ensure the reliability of the results.

Results

The results of IVW showed that increased monocyte count (especially CD14- CD16+ monocyte absolute counts) was negatively correlated with the risk of IBD and its main subtypes. Increased neutrophil count was positively associated with the risk of IBD and ulcerative colitis. Meanwhile, there was no causal relationship between basophil, eosinophil, lymphocyte counts and IBD risk.

Conclusion

These results indicate that a causal relationship exists between circulating leukocytes and the risk of IBD and its subtypes, which confirms the important role that the leukocyte immune system plays in IBD. Our findings provide additional research directions for the clinical prevention and treatment of IBD.

Exploring shared molecular signatures and regulatory mechanisms in nonalcoholic steatohepatitis and inflammatory bowel disease using integrative bioinformatics analysis

The co-existence of inflammatory bowel disease (IBD) and non-alcoholic steatohepatitis (NASH) has raised interest in identifying shared molecular mechanisms and potential therapeutic targets. However, the relationship between these two diseases remains unclear and effective medical treatments are still lacking. Through the bioinformatics analysis in this study, 116 shared differentially expressed genes (SDEGs) were identified between IBD and NASH datasets. GO and KEGG pathway analyses revealed significant involvement of SDEGs in apoptotic processes, cell death, defense response, cytokine and chemokine activity, and signaling pathways. Furthermore, weighted gene co-expression network analysis (WGCNA) identified five shared signature genes associated specifically with IBD and NASH, they were CXCL9, GIMAP2, ADAMTS5, GRAP, and PRF1. These five genes represented potential diagnostic biomarkers for distinguishing patients with diseases from healthy individuals by using two classifier algorithms and were positively related to autophagy, ferroptosis, angiogenesis, and immune checkpoint factors in the two diseases. Additionally, single-cell analysis of IBD and NASH samples highlighted the expression of regulatory genes in various immune cell subtypes, emphasizing their significance in disease pathogenesis. Our work elucidated the shared signature genes and regulatory mechanisms of IBD and NASH, which could provide new potential therapies for patients with IBD and NASH.

Exploring new avenues of health protection: plant-derived nanovesicles reshape microbial communities

Symbiotic microbial communities are crucial for human health, and dysbiosis is associated with various diseases. Plant-derived nanovesicles (PDNVs) have a lipid bilayer structure and contain lipids, metabolites, proteins, and RNA. They offer unique advantages in regulating microbial community homeostasis and treating diseases related to dysbiosis compared to traditional drugs. On the one hand, lipids on PDNVs serve as the primary substances that mediate specific recognition and uptake by bacteria. On the other hand, due to the multifactorial nature of PDNVs, they have the potential to enhance growth and survival of beneficial bacterial while simultaneously reducing the pathogenicity of harmful bacteria. In addition, PDNVs have the capacity to modulate bacterial metabolism, thus facilitating the establishment of a harmonious microbial equilibrium and promoting stability within the microbiota. These remarkable attributes make PDNVs a promising therapeutic approach for various conditions, including periodontitis, inflammatory bowel disease, and skin infection diseases. However, challenges such as consistency, isolation methods, and storage need to be addressed before clinical application. This review aims to explore the value of PDNVs in regulating microbial community homeostasis and provide recommendations for their use as novel therapeutic agents for health protection.

Flavokawain B inhibits NF-κB inflammatory signaling pathway activation in inflammatory bowel disease by targeting TLR2

Inflammatory bowel disease (IBD) is characterized by recurrent inflammatory reactions in the intestinal mucosa, including ulcerative colitis (UC) and Crohn's disease (CD). The expression of Toll-like receptor 2 (TLR2) has been observed to increase during the progression of IBD. Flavokawain B (FKB), a natural chalcone with potent anti-inflammatory activity, exerts its effects through inhibition of the NF-κB pathway. In this study, we aimed to investigate the effects and mechanisms of FKB targeting TLR2 in IBD. C57BL/6 J mice were treated with 2.5% dextran sulfate sodium (DSS) for 7 days, with administration of FKB or TLR2 inhibitor C29 starting on day 2 to establish the model of IBD. In vitro, bone marrow-derived macrophages (BMDMs) were stimulated with the TLR2 agonist Pam3CSK4 to explore the therapeutic effect of FKB and its pharmacological mechanism. Compared with the model group, the FKB-treated group showed significant reductions in colitis-related injuries in the IBD mouse model, including weight gain, increased colon length and reduced inflammation. FKB decreased the formation of TLR2-MyD88 complex by targeting TLR2, leading to suppression of downstream NF-κB signaling pathway. Similar therapeutic effects were observed in the C29-treated group. Additionally, in vitro data suggested that FKB exerted its anti-inflammatory effect by targeting TLR2 and inhibiting Pam3CSK4-induced activation of the NF-κB pathway. The anti-inflammatory effects of FKB were demonstrated through drug affinity responsive target stability assay and cellular thermal shift assay, revealing its binding affinity to TLR2. By inhibiting the activation of the TLR2/NF-κB signaling pathway, FKB effectively prevented DSS-induced IBD and exhibited promising potential as a therapeutic candidate for IBD treatment.

Gut microbiota and intestinal immunity-A crosstalk in irritable bowel syndrome

Irritable bowel syndrome (IBS), one of the most prevalent functional gastrointestinal disorders, is characterized by recurrent abdominal pain and abnormal defecation habits, resulting in a severe healthcare burden worldwide. The pathophysiological mechanisms of IBS are multi-factorially involved, including food antigens, visceral hypersensitivity reactions, and the brain-gut axis. Numerous studies have found that gut microbiota and intestinal mucosal immunity play an important role in the development of IBS in crosstalk with multiple mechanisms. Therefore, based on existing evidence, this paper elaborates that the damage and activation of intestinal mucosal immunity and the disturbance of gut microbiota are closely related to the progression of IBS. Combined with the application prospect, it also provides references for further in-depth exploration and clinical practice.

A polyphenol-rich açaí seed extract protects against 5-fluorouracil-induced intestinal mucositis in mice through the TLR-4/MyD88/PI3K/mTOR/NF-κBp65 signaling pathway

Açaí seed extract (ASE) is obtained from Euterpe oleracea Mart. (açaí) plant (Amazon region) has high nutritional and functional value. ASE is rich in polyphenolic compounds, mainly proanthocyanidins. Proanthocyanidins can modulate the immune system and oxidative stress by inhibiting the toll-like receptor-4 (TLR-4)/myeloid differentiation primary response 88 (MyD88)/nuclear factor-κB (NF-κB) pathway. A great deal of evidence suggests that inflammatory cytokines and oxidative stress contribute to the pathogenesis of intestinal mucositis, and these events can lead to intestinal dysmotility. We hypothesized that ASE acts as an anti-inflammatory and antioxidant compound in intestinal mucositis induced by 5-fluorouracil (5-FU) through modulation of the TLR-4/MyD88/phosphatidylinositol-3-kinase α/mechanistic target of rapamycin/NF-κBp65 pathway. The animals were divided into linear 5-FU (450 mg/kg) and 5-FU + ASE (10, 30, and 100 mg/kg) groups. The weight loss of the animals was evaluated daily. Samples from duodenum, jejunum, and ileum were obtained for histopathological, biochemical, and functional analyses. ASE reduced weight loss, inflammatory parameters (interleukin-1β; tumor necrosis factor-α; myeloperoxidase activity) and the gene expression of mediators involved in the TLR-2/MyD88/NF-κB pathway. ASE prevented histopathological changes with beneficial effects on gastrointestinal transit delay, gastric emptying, and intestinal absorption/permeability. In conclusion, ASE protects the integrity of the intestinal epithelial barrier by inhibiting the TLR/MyD88/PI3K/mechanistic target of rapamycin/NF-κBp65 pathway.

Endoplasmic reticulum stress is upregulated in inflammatory bowel disease and contributed TLR2 pathway-mediated inflammatory response

OBJECTIVE

Endoplasmic reticulum stress (ERS) and Toll-like receptor 2 (TLR2) signaling play an important role in inflammatory bowel disease (IBD); however, the link between TLR2 and ERS in IBD is unclear. This study investigated whether Thapsigargin (TG) -induced ER protein expression levels contributed to TLR2-mediated inflammatory response.

METHODS

The THP-1 cells were treated with TLR2 agonist (Pam3CSK4), ERS inducer Thapsigargin (TG) or inhibitor (TUDCA). The mRNA expressions of TLR1-TLR10 were detected by qPCR. The production and secretion of inflammatory factors were detected by PCR and ELISA. Immunohistochemistry was used to detect the expressions of GRP78 and TLR2 in the intestinal mucosa of patients with Crohn's disease (CD). The IBD mouse model was established by TNBS in the modeling group. ERS inhibitor (TUDCA) was used in the treatment group.

RESULTS

The expression of TLRs was detected via polymerase chain reaction (PCR) in THP-1 cells treated by ERS agonist Thapsigargin (TG). According to the findings, TG could promote TLR2 and TLR5 expression. Subsequently, in TLR2 agonist Pam3CSK4 induced THP-1 cells, TG could lead to increased expression of the inflammatory factors such as TNF-α, IL-1β and IL-8, and ERS inhibitor (TUDCA) could block this effect. However, Pam3CSK4 did not significantly impact the GRP78 and CHOP expression. Based upon the immunohistochemical results, TLR2 and GRP78 expression were significantly increased in the intestinal mucosa of patients with Crohn's disease (CD). For in vivo experiments, TUDCA displayed the ability to inhibit intestinal mucosal inflammation and reduce GRP78 and TLR2 proteins.

CONCLUSIONS

ERS and TLR2 is upregulated in inflammatory bowel disease, ERS may promote TLR2 pathway-mediated inflammatory response. Moreover, ERS and TLR2 signaling could be novel therapeutic targets for IBD.

Dysfunctional intestinal microvascular endothelial cells: Insights and therapeutic implications in gastrointestinal inflammation

The intestinal microvascular endothelium plays a crucial role in orchestrating host responses to inflammation within the gastrointestinal tract. This review delves into the unique aspects of intestinal microvascular endothelial cells, distinct from those of larger vessels, in mediating leukocyte recruitment, maintaining barrier integrity, and regulating angiogenesis during inflammation. Specifically, their role in the pathogenesis of inflammatory bowel diseases, where dysregulated endothelial functions contribute to the disease progression, is reviewed. Furthermore, this review discusses the isolation technique for these cells and commonly used adhesion molecules for in vitro and in vivo experiments. In addition, we reviewed the development and therapeutic implications of a biologic agent targeting the interaction between α4β7 integrin on T lymphocytes and mucosal addressin cellular adhesion molecule-1 on gut endothelium. Notably, vedolizumab, a humanized monoclonal antibody against α4β7 integrin, has shown promising outcomes in inflammatory bowel diseases and other gastrointestinal inflammatory conditions, including chronic pouchitis, immune checkpoint inhibitor-induced colitis, and acute cellular rejection post-intestinal transplantation.

Potential mitigation of titanium dioxide nanoparticles against 2,4,6-trinitrobenzene sulfonic acid (TNBS)-induced colitis through inhibiting the canonical NF-κB pathway

Titanium dioxide nanoparticles (TiO2 NPs) have been widely employed in various industry fields, which makes consumers concerned about their health impact. Our previous work displayed that TiO2 NPs participated in the mitigation of TNBS-induced colitis, but the mechanism is still unknown. This work aimed to explore the role of oxidative stress and NF-κB pathway in the effect of TiO2 NPs on TNBS-induced colitis. The results showed that TiO2 NPs administration reduced the DAI score of colitis mice after TNBS enema. TiO2 NPs did not alter oxidative stress status (GSH/GSSG), but repaired the gut dysbacteriosis and inhibited the canonical NF-κB pathway activation in TNBS-induced colitis mice, manifested as a decrease in pathogenic bacteria and an increase in beneficial bacteria, as well as down-regulation of toll-like receptors (TLRs), IKKα, IKKβ, p65 and pro-inflammatory cytokines (IL-1β, IL-6, TNF-α and IFN-γ) in mRNA level, and the increased transcription of anti-inflammatory cytokines (IL-10, TGF-β, and IL-12), along with the declined protein level of TNF-α in TiO2 NPs treated colitis mice. The present study suggested that oral TiO2 NPs administration inhibited the canonical NF-κB pathway activation by repairing gut dysbacteriosis, which made a predominant role in alleviating colitis. These findings provided a new perspective for exploring the safety of TiO2 NPs.

Inference of differential gene regulatory networks using boosted differential trees

Summary

Diseases can be caused by molecular perturbations that induce specific changes in regulatory interactions and their coordinated expression, also referred to as network rewiring. However, the detection of complex changes in regulatory connections remains a challenging task and would benefit from the development of novel nonparametric approaches. We develop a new ensemble method called BoostDiff (boosted differential regression trees) to infer a differential network discriminating between two conditions. BoostDiff builds an adaptively boosted (AdaBoost) ensemble of differential trees with respect to a target condition. To build the differential trees, we propose differential variance improvement as a novel splitting criterion. Variable importance measures derived from the resulting models are used to reflect changes in gene expression predictability and to build the output differential networks. BoostDiff outperforms existing differential network methods on simulated data evaluated in four different complexity settings. We then demonstrate the power of our approach when applied to real transcriptomics data in COVID-19, Crohn's disease, breast cancer, prostate adenocarcinoma, and stress response in Bacillus subtilis. BoostDiff identifies context-specific networks that are enriched with genes of known disease-relevant pathways and complements standard differential expression analyses.

Availability and implementation

BoostDiff is available at https://github.com/scibiome/boostdiff_inference.

Antagonizing interleukin-5 receptor ameliorates dextran sulfate sodium-induced experimental colitis in mice through reducing NLRP3 inflammasome activation

Inflammatory bowel disease (IBD) is a condition characterized by inflammation in the gastrointestinal tract. Reducing intestinal inflammation is a promising approach for treating IBD. The nucleotide-binding oligomerization domain-like receptor family pyrin domain-containing protein 3 (NLRP3) inflammasome, a critical component of the innate immune system, is implicated in the pathogenesis of IBD. Therefore, inhibiting NLRP3 inflammasome activation is a potential therapeutic strategy for IBD. In this study, we investigated the effects of the interleukin-5 (IL-5) receptor antagonist YM-90709 on dextran sulfate sodium-induced experimental colitis in mice. We found that YM-90709 reduced the expressions of IL-1β and caspase-1 p20 in the colon and ameliorated colitis. Furthermore, we identified YM-90709 as an effective agent for inhibiting NLRP3 inflammasome activation. Knockdown of IL-5 receptor or using an inhibitor of STAT5, a key transcription factor downstream of the IL-5/IL-5 receptor signal pathway, also reduced NLRP3 inflammasome-dependent IL-1β release and ASC speck formation. Our study is the first to demonstrate that the NLRP3 inflammasome may be a downstream signal of IL-5/IL-5 receptor and that YM-90709 protects against IBD by inhibiting IL-5 receptor. These findings suggest a new strategy for regulating intestinal inflammation and managing IBD.

Role of Sam68 as an adaptor protein in inflammatory signaling

Sam68 is a ubiquitously expressed KH-domain containing RNA-binding protein highly studied for its involvement in regulating multiple steps of RNA metabolism. Sam68 also contains multiple protein-protein interaction regions such as proline-rich regions, tyrosine phosphorylation sites, and arginine methylation sites, all of which facilitate its participation as an adaptor protein in multiple signaling pathways, likely independent of its RNA-binding role. This review focuses on providing a comprehensive report on the adaptor roles of Sam68 in inflammatory signaling and inflammatory diseases. The insights presented here have the potential to open new avenues in inflammation research and justify targeting Sam68 to control aberrant inflammatory responses.

Ginseng-derived nanoparticles alleviate inflammatory bowel disease via the TLR4/MAPK and p62/Nrf2/Keap1 pathways

Inflammatory bowel disease (IBD) is closely linked to the homeostasis of the intestinal environment, and exosomes can be used to treat IBD due to their high biocompatibility and ability to be effectively absorbed by the intestinal tract. However, Ginseng-derived nanoparticles (GDNPs) have not been studied in this context and their mechanism of action remains unclear. Here, we investigated GDNPs ability to mediate intercellular communication in a complex inflammatory microenvironment in order to treat IBD. We found that GDNPs scavenge reactive oxygen species from immune cells and intestinal epithelial cells, inhibit the expression of pro-inflammatory factors, promote the proliferation and differentiation of intestinal stem cells, as well as enhancing the diversity of the intestinal flora. GDNPs significantly stabilise the intestinal barrier thereby promoting tissue repair. Overall, we proved that GDNPs can ameliorate inflammation and oxidative stress in vivo and in vitro, acting on the TLR4/MAPK and p62/Keap1/Nrf2 pathways, and exerting an anti-inflammatory and antioxidant effect. GDNPs mitigated IBD in mice by reducing inflammatory factors and improving the intestinal environment. This study offers new evidence of the potential therapeutic effects of GDNPs in the context of IBD, providing the conceptual ground for an alternative therapeutic strategy.

Bioaccumulation, microbiome composition and immunity, and epigenetic signatures associated with exposure to spherical, fibrous, and fragmented microplastics in the mussel Mytilus galloprovincialis

Microplastic (MP) pollution has become a major global concern due to the widespread use and discharge of plastics into the environment. However, very few studies have assessed the potential variations in the toxicity of MPs according to their shape and size. Therefore, our study sought to identify the biotoxic effects of spherical, fiber-shaped, and fragment-shaped polyethylene terephthalate MPs of different sizes at different concentrations on the Mediterranean mussel Mytilus galloprovincialis. The survival rate after exposure to small-sized MPs was lower than that observed for the larger type MPs. Bioaccumulation of MPs was different depending on the exposure periods and MP shapes. Interestingly, the fiber-shaped MPs underwent morphological modifications in the mussel body upon uptake. MP exposure also increased the global DNA methylation levels (i.e., an epigenetic signature), expression of the microbiota immunity-related toll-like receptor gene, and alteration of the gut microbial composition in the mussel. These findings indicated that MPs of different shapes and sizes at different concentrations can alter the bioaccumulation sensitivity of mussels according to the exposure periods, and the balance of gut immunity and epigenetic process. Furthermore, our results demonstrated that MPs of different shapes, particularly fiber types, can undergo morphological modification in mussel tissues, thus posing a hazardous threat.

The NF-κB signaling system in the immunopathogenesis of inflammatory bowel disease

Inflammatory bowel disease (IBD) is an idiopathic, chronic condition characterized by episodes of inflammation in the gastrointestinal tract. The nuclear factor κB (NF-κB) system describes a family of dimeric transcription factors. Canonical NF-κB signaling is stimulated by and enhances inflammation, whereas noncanonical NF-κB signaling contributes to immune organogenesis. Dysregulation of NF-κB factors drives various inflammatory pathologies, including IBD. Signals from many immune sensors activate NF-κB subunits in the intestine, which maintain an equilibrium between local microbiota and host responses. Genetic association studies of patients with IBD and preclinical mouse models confirm the importance of the NF-κB system in host defense in the gut. Other studies have investigated the roles of these factors in intestinal barrier function and in inflammatory gut pathologies associated with IBD. NF-κB signaling modulates innate and adaptive immune responses and the production of immunoregulatory proteins, anti-inflammatory cytokines, antimicrobial peptides, and other tolerogenic factors in the intestine. Furthermore, genetic studies have revealed critical cell type-specific roles for NF-κB proteins in intestinal immune homeostasis, inflammation, and restitution that contribute to the etiopathology of IBD-associated manifestations. Here, we summarize our knowledge of the roles of these NF-κB pathways, which are activated in different intestinal cell types by specific ligands, and their cross-talk, in fueling aberrant intestinal inflammation. We argue that an in-depth understanding of aberrant immune signaling mechanisms may hold the key to identifying predictive or prognostic biomarkers and developing better therapeutics against inflammatory gut pathologies.

Dendritic cells: the yin and yang in disease progression

Dendritic cells (DCs) are antigen presenting cells that link innate and adaptive immunity. DCs have been historically considered as the most effective and potent cell population to capture, process and present antigens to activate naïve T cells and originate favorable immune responses in many diseases, such as cancer. However, in the last decades, it has been observed that DCs not only promote beneficial responses, but also drive the initiation and progression of some pathologies, including inflammatory bowel disease (IBD). In line with those notions, different therapeutic approaches have been tested to enhance or impair the concentration and role of the different DC subsets. The blockade of inhibitory pathways to promote DCs or DC-based vaccines have been successfully assessed in cancer, whereas the targeting of DCs to inhibit their functionality has proved to be favorable in IBD. In this review, we (a) described the general role of DCs, (b) explained the DC subsets and their role in immunogenicity, (c) analyzed the role of DCs in cancer and therapeutic approaches to promote immunogenic DCs and (d) analyzed the role of DCs in IBD and therapeutic approaches to reduced DC-induced inflammation. Therefore, we aimed to highlight the "yin-yang" role of DCs to improve the understand of this type of cells in disease progression.

Cinnamic Acid Ameliorates Acetic Acid-induced Inflammatory Response through Inhibition of TLR-4 in Colitis Rat Model

BACKGROUND

Cinnamic acid, an active compound in cinnamon spp., has anti-inflammatory and antioxidant characteristics and is favorable in managing inflammatory bowel diseases.

OBJECTIVES

Evaluate cinnamic acid's effects on colitis in rats.

METHODS

To induce colitis in experimental rats, excluding the sham group, a 4% intrarectal solution of acetic acid was administered. The rats were then given oral doses of cinnamic acid at 30, 45, and 90 mg/kg for two days. The animals were assessed for macroscopic and microscopic changes, and the levels of inflammatory mediators such as tumor necrosis factor-alpha (TNF-α), interleukin-6 (IL-6), and myeloperoxidase (MPO) were measured using Eliza kits. Additionally, real-time PCR was performed to examine the gene level of toll-like receptor 4 (TLR-4) in the colon.

RESULTS

Effective reduction of inflammation in acetic acid-induced colitis was achieved through Cinnamic acid administration at doses of 45 and 90 mg/kg. The decrease was achieved by inhibiting the activities of TNF-α, IL-6, and MPO while downregulating the expression of TLR-4. It is important to note that macroscopic and microscopic evaluations were significant in determining the effectiveness of cinnamic acid in reducing inflammation.

CONCLUSION

Downregulation of inflammatory cytokines and TLR-4 expression may contribute to cinnamic acid's anti-inflammatory effect.

Lactiplantibacillus plantarum HY7718 Improves Intestinal Integrity in a DSS-Induced Ulcerative Colitis Mouse Model by Suppressing Inflammation through Modulation of the Gut Microbiota

Inflammatory bowel disease (IBD), a chronic condition that causes persistent inflammation in the digestive system, is closely associated with the intestinal microbiome. Here, we evaluated the effects of Lactiplantibacillus plantarum HY7718 (HY7718) on IBD symptoms in mice with dextran sulfate sodium (DSS)-induced colitis. Oral administration of HY7718 led to significant improvement in the disease activity index score and the histological index, as well as preventing weight loss, in model mice. HY7718 upregulated the expression of intestinal tight junction (TJ)-related genes and downregulated the expression of genes encoding pro-inflammatory cytokines and genes involved in the TLR/MyD88/NF-κB signaling pathway. Additionally, HY7718 reduced the blood levels of pro-inflammatory cytokines, as well as reversing DSS-induced changes to the composition of the intestinal microbiome. HY7718 also increased the percentage of beneficial bacteria (Lactiplantibacillus and Bifidobacterium), which correlated positively with the expression of intestinal TJ-related genes. Finally, HY7718 decreased the population of pathogens such as Escherichia, which correlated with IBD symptoms. The data suggest that HY7718 improves intestinal integrity in colitis model mice by regulating the expression of TJ proteins and inflammatory cytokines, as well as the composition of the intestinal microflora. Thus, L. plantarum HY7718 may be suitable as a functional supplement that improves IBD symptoms and gut health.

Toll-like receptors in inflammatory bowel disease: A review of the role of phytochemicals

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammation within the gastrointestinal tract with a remarkable impact on patients' quality of life. Toll-like receptors (TLR), as a key contributor of immune system in inflammation, has a critical role in the pathogenesis of IBD and thus, can be a suitable target of therapeutic agents. Medicinal plants have long been considered as a source of bioactive agents for different diseases, including IBD.

PURPOSE

This review discusses current state of the art on the role of plant-derived compounds for the management of IBD with a focus on TLRs.

METHODS

Electronic database including PubMed, Web of Science, and Scopus were searched up to January 2023 and all studies in which anticolitis effects of a phytochemical was assessed via modulation of TLRs were considered.

RESULTS

Different categories of phytochemicals, including flavonoids, lignans, alkaloids, terpenes, saccharides, and saponins have demonstrated modulatory effects on TLR in different animal and cell models of bowel inflammation. Flavonoids were the most studied phytochemicals amongst others. Also, TLR4 was the most important type of TLRs which were modulated by phytochemicals. Other mechanisms such as inhibition of pro-inflammatory cytokines, nuclear factor-κB pathway, nitric oxide synthesis pathway, cyclooxygenase-2, lipid peroxidation, as well as induction of endogenous antioxidant defense mechanisms were also reported for phytochemicals in various IBD models.

CONCLUSION

Taken together, a growing body of pre-clinical evidence support the efficacy of herbal compounds for the treatment of IBD via modulation of TLRs. Future clinical studies are recommended to assess the safety and efficacy of these compounds in human.

Gut-brain axis interacts with immunomodulation in inflammatory bowel disease

The brain and the gastrointestinal (GI) tract are important sensory organs in the body and the two-way interaction that exists between them regulates key physiological and homeostatic functions. A growing body of research suggests that this bidirectional communication influences the development and progression of functional GI disorders and plays an important role in the treatment of central nervous system (CNS) disorders. Inflammatory bowel disease (IBD) is a classic intestinal disorder with a high prevalence but still unclear pathogenesis that has been widely discussed in recent years. However, in the studies available to date, we find that many authors have chosen to discuss the influence of the brain on intestinal disorders from the top down, starting with physical and psychological disorders. Coming very naturally, based on these substantial research evidence, we focus on exploring the links between bidirectional communication in the gut-brain axis and IBD, and highlight the role of the gut microbiota, vagus nerve (VN), receptors and immune cells involved in regulating IBD through the gut-brain axis in this review.

New Promising Routes in Peptic Ulcers: Toll-like Receptors and Semaphorins

Peptic ulcers (PU) are one of the commonest yet problematic diseases found to be existing in the majority of the population. Today, drugs from a wide range of therapeutic classes are available for the management of the disease. Still, the complications of the condition are difficult to tackle and the side effect profile is quite a concern. The literature indicates that Toll-like receptors (TLRs) and Semaphorins (SEMAs) have been under study for their various pharmacological actions over the past few decades. Both these signalling pathways are found to regulate immunological and inflammatory responses. Moreover, receptors and signalling molecules from the family of TLRs and SEMAs are found to have bacterial recognition and antibacterial properties which are essential in eradicating Helicobacter pylori (H. pylori), one of the major causative agents of PU. Our understanding of SEMAs, a class of proteins involved in cell signalling, is relatively less developed compared to TLRs, another class of proteins involved in the immune response. SEMAs and TLRs play different roles in biological processes, with SEMAs primarily involved in guiding cell migration and axon guidance during development, while TLRs are responsible for recognizing pathogens and initiating an immune response. Here, in this review, we will discuss in detail the signalling cascade of TLRs and SEMAs and thereby understand its association with PU for future therapeutic targeting. The review also aims at providing an overview of the study that has been into exploring the role of these signalling pathways in the management of PU.