Clinical importance of IL-22 cascade in IBD

Effects of methylglyoxal on intestine and microbiome composition in aged mice

BACKGROUND

Methylglyoxal (MGO), a highly reactive precursor of advanced glycation end products (AGEs), is endogenously produced and prevalent in various ultra-processed foods. MGO has emerged as a significant precursor implicated in the pathogenesis of type 2 diabetes and neurodegenerative diseases. To date, the effects of dietary MGO on the intestine have been limited explored. Thus, this study investigates the impact of prolonged oral administration of MGOs on gut health in aged mice.

METHODS

Aged mice received MGO chronically (100 mg/kg/day) for 4 weeks Intestinal samples were analyzed using RT-PCR and immunohistochemistry for proinflammatory cytokines, permeability markers, and tight junction proteins. 16S rRNA gene-based microbiome analysis was also performed to characterize microbiome composition and its metabolic potential.

RESULTS

MGO treatment induced notable alterations at the intestinal level, characterized by an increased formation of MGO-glycated proteins with a concurrent induction of a pro-inflammatory status and reduced expression and delocalization of zonulin-1 and occludin, tight junction proteins. Changes in intestinal morphology were also observed, including hyperproliferation of Paneth cells and an augmented thickness of the intestinal mucus layer, as indicated by immunohistochemical data from MGO-treated mice. Investigation into the microbiota composition revealed that MGO is effective in selectively modifying its composition and metabolic pathways. A decreased abundance of bacterial genera associated with the production of acetic and butyric acids (i.e. Harryflintia, Intestinimonas and Ruminococcaceae genera) and a substantial increase in Lachnospiraceae and Akkermansia genera were found in MGO-treated mice.

CONCLUSION

These findings highlight how dietary MGO can affect intestinal balance, providing valuable insights into the potential links between glycotoxins, gut microbiota, and overall gut functionality.

Effects of psychological stress on inflammatory bowel disease via affecting the microbiota-gut-brain axis

ABSTRACT

Inflammatory bowel disease (IBD) is an idiopathic intestinal inflammatory condition with chronic and relapsing manifestations and is characterized by a disturbance in the interplay between the intestinal microbiota, the gut, and the brain. The microbiota-gut-brain axis involves interactions among the nervous system, the neuroendocrine system, the gut microbiota, and the host immune system. Increasing published data indicate that psychological stress exacerbates the severity of IBD due to its negative effects on the microbiota-gut-brain axis, including alterations in the stress response of the hypothalamic-pituitary-adrenal (HPA) axis, the balance between the sympathetic nervous system and vagus nerves, the homeostasis of the intestinal flora and metabolites, and normal intestinal immunity and permeability. Although the current evidence is insufficient, psychotropic agents, psychotherapies, and interventions targeting the microbiota-gut-brain axis show the potential to improve symptoms and quality of life in IBD patients. Therefore, further studies that translate recent findings into therapeutic approaches that improve both physical and psychological well-being are needed.

Fiber- and acetate-mediated modulation of MHC-II expression on intestinal epithelium protects from Clostridioides difficile infection

Here, we explore the relationship between dietary fibers, colonic epithelium major histocompatibility complex class II (MHC-II) expression, and immune cell interactions in regulating susceptibility to Clostridioides difficile infection (CDI). We find that a low-fiber diet increases MHC-II expression in the colonic epithelium, which, in turn, worsens CDI by promoting the development of pathogenic CD4+ intraepithelial lymphocytes (IELs). The influence of dietary fibers on MHC-II expression is mediated by its metabolic product, acetate, and its receptor, free fatty acid receptor 2 (FFAR2). While acetate activation of FFAR2 on epithelial cells helps resist CDI, it does not directly regulate MHC-II expression. Instead, MHC-II is regulated by FFAR2 in type 3 innate lymphoid cells (ILC3s). Acetate enhances interleukin-22 (IL-22) production by ILC3s, which then suppresses MHC-II expression on the colonic epithelium. In conclusion, a low-fiber diet reduces acetate-induced IL-22 production by ILC3s, leading to increased MHC-II on the colonic epithelium. This change affects recovery from CDI by expanding the population of pathogenic CD4+ IELs.

Engineering probiotic Escherichia coli for inflammation-responsive indoleacetic acid production using RiboJ-enhanced genetic circuits

BACKGROUND

As our understanding of gut microbiota's metabolic impacts on health grows, the interest in engineered probiotics has intensified. This study aimed to engineer the probiotic Escherichia coli Nissle 1917 (EcN) to produce indoleacetic acid (IAA) in response to gut inflammatory biomarkers thiosulfate and nitrate.

RESULTS

Genetic circuits were developed to initiate IAA synthesis upon detecting inflammatory signals, optimizing a heterologous IAA biosynthetic pathway, and incorporating a RiboJ insulator to enhance IAA production. The engineered EcN strains demonstrated increased IAA production in the presence of thiosulfate and nitrate. An IAA-responsive genetic circuit using the IacR transcription factor from Pseudomonas putida 1290 was also developed for real-time IAA monitoring.

CONCLUSIONS

Given IAA's role in reducing gastrointestinal inflammation, further refinement of this strain could lead to effective, in situ IAA-based therapies. This proof-of-concept advances the field of live biotherapeutic products and offers a promising approach for targeted therapy in inflammatory bowel diseases.

Anti-Inflammatory Effects of Algae-Derived Biomolecules in Gut Health: A Review

Under physiological conditions, the inflammatory response acts as a biological defense against tissue damage or infection, and is rapidly resolved once the infection is cleared. However, chronic inflammatory diseases, including inflammatory bowel disease (IBD), have become increasingly widespread in the last decades, placing a burden on the quality of life of affected people and on healthcare systems worldwide. Available drug therapies are often ineffective due to the chronic nature of these diseases, and prolonged administration of drugs can result in severe side effects for the patient or a lack of efficacy. In addition, there is the growing problem of bacterial resistance to synthetic antibiotics. Together, these factors have led to a strong research focus on the discovery of natural products capable of treating IBD. Recently, there has been a growing interest in compounds derived from marine sources, mainly algae, due to their bioactive secondary metabolites with anti-inflammatory properties well known in the literature. Based on this evidence, this review aimed to evaluate the anti-inflammatory potential of algae-derived biomolecules in IBD. In particular, interesting species from green algae (e.g., Chlorella vulgaris and Ulva pertusa), brown algae (e.g., Macrocystis pyrifera and Ecklonia cava) and red algae (e.g., Porphyra tenera and Grateloupia turuturu) are included in this review due to their proven anti-inflammatory properties. For this purpose, an extensive literature search was conducted using several databases. The results suggest that both macroalgae and microalgae have remarkable potential for IBD therapy due to the anti-inflammatory and antioxidant activities of their bioactive compounds. However, while the preclinical evidence is encouraging, further and long-term clinical studies are needed to better understand their mechanisms of action in order to determine the true efficacy of marine algae in the treatment of IBD.

Dietary supplementation with compound microecological preparations: effects on the production performance and gut microbiota of lactating female rabbits and their litters

Early weaning is frequently accompanied by a significant increase in diarrhea and mortality rates, which reduces rabbits' performance. Although antibiotics can reduce pathogenic bacteria, they also harm beneficial microorganisms and disrupt the normal intestinal microbiota balance. In order to find non-residue and non-toxic alternatives to antibiotics to ensure the safety of animal products, we conducted a study on the effect of compound microecological preparations supplementation on lactating female rabbits and their offspring. A total of 60 female rabbits were randomly assigned to four groups: CON, supplemented with probiotics at 3, 6, and 9 g/female rabbit/day from day 24 of gestation until weaning. We observed that probiotics supplementation significantly enhanced production performance (P < 0.05), immune and antioxidant function (P < 0.05), as well as intestinal flora composition in lactating rabbits and their offspring. Notably, compared with the control group, the experimental group exhibited a 19.23%, 44.22%, and 24.57% increase in milk yield (P = 0.002). Regarding rabbit growth performance, the average body weight of young rabbits in the experimental group showed a significant increase of 3.59%, 10.22%, and 6.74% at day 35 (P = 0.022), whereas the average daily gain (ADG) of rabbits aged between 21 and 35 days was significantly elevated by 4.94%, 17.06%, and 6.28% in the experimental group (P < 0.001). In conclusion, probiotics supplementation can significantly enhance lactation performance, promote growth and disease resistance in rabbits, as well as improve intestinal health when administered at a dosage of 6 g/day. Moreover, the limited sample size in this study may hinder the detection of subtle effects, and augmenting the sample size will bolster the reliability of the study findings.

IMPORTANCE

The intestinal environment of rabbits is fragile and susceptible to environmental influences, leading to inflammatory intestinal diseases. Adding antibiotics to rabbit feed can achieve the effect of preventing and treating inflammation, which can also lead to the imbalance of the gut microbiota and residual antibiotics in agricultural products. Composite probiotics are live microbial feed additives composed of various ratios of probiotics and have become the most promising alternative to antibiotics due to their residue-free and non-toxic properties. The aim of this study was to investigate the impact of compound probiotics on lactating female rabbits and their offspring. Our findings highlight the potential of compound microecological preparations as an effective strategy for enhancing lactation performance, immune function, and antioxidant capacity in rabbits. The supplementation of probiotics through rabbit milk offers a promising approach to optimize the growth and health outcomes of newborn rabbits.

Probiotic Bacillus pumilus LV149 enhances gut repair, modulates microbiota, and alters transcriptome in DSS-induced colitis mice

Purpose

Gut microbiota dysbiosis significantly impacts ulcerative colitis (UC) progression and exacerbation. Probiotics show promise in UC management. This study evaluated the effects of different doses of Bacillus pumilus LV149, an aquatic-derived probiotic, on gut injury repair in male C57BL/6 mice with dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) and investigated the underlying mechanisms.

Methods

UC was induced by allowing mice free access to a 3% DSS solution for 7 days, with concurrent daily oral gavage of either a low (LV149-L, 1 × 108 CFU/day/mouse) or high (LV149-H, 1 × 109 CFU/day/mouse) dose of LV149. The effects were assessed through physiological parameters, intestinal barrier integrity, inflammation, gut microbiota composition, and transcriptomic changes.

Results

LV149 significantly improved pathological symptoms, including weight loss and disease activity index (DAI), and reduced colon shortening in a dose-dependent manner and inflammatory damage. The intervention also restored gut barrier function by upregulating mucins, goblet cell counts, and tight junction proteins (ZO-1, occludin, and claudin-1) in colonic tissue, along with reducing serum lipopolysaccharide (LPS) levels. Notably, only the LV149-H significantly decreased the expression of pro-inflammatory cytokines TNF-α, IL-1β, and IL-6, while both doses increased the expression of the anti-inflammatory cytokine IL-10 in a dose-dependent in colonic tissue. LV149 further modulated the gut microbiota, increasing beneficial bacteria and reducing pathogenic populations. Transcriptomic analysis indicated that LV149-L may exert gut repair effects via the IL-17 signaling pathway, whereas LV149-H appears to act through the JAK-STAT signaling pathway.

Conclusion

This study demonstrated that LV149, particularly at a higher dose, effectively mitigated DSS-induced colonic injury by modulating gut microbiota, enhancing gut barrier integrity, and reducing inflammation. The dose-dependent effects underscored LV149-H's potential as a therapeutic agent for UC due to its stronger anti-inflammatory properties and gut-protective effects.

Live Akkermansia muciniphila boosts dendritic cell retinoic acid synthesis to modulate IL-22 activity and mitigate colitis in mice

BACKGROUND

The interplay between gut microbiota and immune responses is crucial in ulcerative colitis (UC). Though Akkermansia muciniphila (Akk) shows therapeutic potential, the mechanisms remain unclear. This study sought to investigate differences in therapeutic efficacy among different forms or strains of Akk and elucidate the underlying mechanisms.

RESULTS

Employing a dextran sulfate sodium (DSS)-induced colitis mouse model, we assessed Akk's impact on colitis using cellular cytokine analysis, immune phenotyping, proteomics, and biochemical methods. Our results suggest that treatment with live Akk effectively reduced colitis in the DSS-induced model, whereas heat-inactivated Akk did not yield the same results. Notably, Akk exhibited protective properties by promoting the secretion of IL-22 by Group 3 innate lymphoid cells (ILC3s), as evidenced by the absence of protection in IL-22 knockout mice. Additionally, Akk augmented the population of CD103+CD11b- dendritic cells (DCs) and enhanced their retinoic acid (RA) synthesis through the modulation of RALDH2, a crucial enzyme in RA metabolism. The depletion of RALDH2 in DCs diminished Akk's protective properties and impaired IL-22-mediated mucosal healing. Mechanistically, Akk activated RA production in DCs by enhancing the JAK2-STAT3 signaling pathway. Additionally, various strains of Akk may exhibit differing abilities to alleviate colitis, with the novel strain Am06 derived from breast milk showing consistent efficacy similar to the reference strain.

CONCLUSIONS

In summary, our findings indicate that certain strains of Akk may mitigate colitis through the promotion of RA synthesis and IL-22 secretion, underscoring the potential efficacy of Akk as a therapeutic intervention for the management of UC. Video Abstract.

Targeting the Calcium-Sensing Receptor in Chemically Induced Medium-Grade Colitis in Female BALB/C Mice

BACKGROUND/OBJECTIVES

The extracellular calcium-sensing receptor (CaSR) is a multifunctional receptor proposed as a possible drug target for inflammatory bowel disease. We showed previously that CaSR inhibition with NPS 2143, a negative allosteric modulator of the CaSR, somewhat ameliorated the symptoms of chemically induced severe colitis in mice. However, it was unclear whether the potential of CaSR inhibition to reduce colitis may have been overshadowed by the severity of the induced inflammation in our previous study. Therefore, we tested if CaSR inhibition could prevent medium-grade colitis.

METHODS

Female BALB/c mice were treated with NPS 2143 or a vehicle prior to the induction of colitis with 2.5% DSS. On the day of sacrifice, colons and plasma were collected. The histology score was determined based on hematoxylin-eosin-stained sections. Mucin content, proliferation (Ki67), and immune cell infiltration (CD3 and CD20) were quantified based on immunostainings. Gene expression was measured by RT-qPCR.

RESULTS

Treatment with NPS 2143 had no effect on the clinical symptom score of the mice. However, the colons of the mice in the treated group were significantly longer (p < 0.05), and NPS 2143 significantly reduced colon ulceration (p < 0.05). The treatment also significantly reduced the expression of COX2 in the proximal colon and IL-22 in the distal colon. The proliferation of cells in the lymph nodes was significantly lower after the treatment, but no difference was observed in the epithelial cells.

CONCLUSIONS

In summary, while NPS 2143 had an anti-inflammatory effect on medium-grade colitis, this effect appeared to be milder than in severe colitis, as observed previously, indicating that the effectiveness of CaSR inhibition as an anti-inflammatory measure in the colon is proportional to disease severity.

Implications of glycosylation for the development of selected cytokines and their derivatives for medical use

Cytokines are important regulators of immune responses, making them attractive targets for autoimmune diseases and cancer therapeutics. Yet, the significance of cytokine glycosylation remains underestimated. Many cytokines carry N- and O-glycans and some even undergo C-mannosylation. Recombinant cytokines produced in heterologous host cells may lack glycans or exhibit a different glycosylation pattern such as varying levels of galactosylation, sialylation, fucosylation or xylose addition compared to their human counterparts, potentially impacting critical immune interactions. We focused on cytokines that are currently utilized or designed in advanced therapeutic formats, including immunocytokines, fusokines, engager cytokines, and genetically engineered 'supercytokines.' Despite the innovative designs of these cytokine derivatives, their glycosylation patterns have not been extensively studied. By examining the glycosylation of the human native cytokines, G-CSF and GM-CSF, interferons β and γ, TNF-α and interleukins-2, -3 -4, -6, -7, -9, -12, -13, -15, -17A, -21, and - 22, we aim to assess its potential impact on their therapeutic derivatives. Understanding the glycosylation of the native cytokines could provide critical insights into the safety, efficacy, and functionality of these next-generation cytokine therapies, affecting factors such as stability, bioactivity, antigenicity, and half-life. This knowledge can guide the choice of optimal expression hosts for production and advance the development of effective cytokine-based therapeutics and synthetic immunology drugs.

Indigo naturalis as a potential drug in the treatment of ulcerative colitis: a comprehensive review of current evidence

CONTEXT

Ulcerative colitis (UC) is an intractable inflammatory bowel disease that threatens the health of patients. The limited availability of therapeutic strategies makes it imperative to explore more efficient and safer drugs. Indigo naturalis (IN) is a traditional Chinese medicine that possesses many pharmacological activities, including anti-inflammatory, antioxidant, and immunomodulatory activities. The treatment potential of IN for UC has been proven by numerous preclinical and clinical studies in recent years.

OBJECTIVE

This article provides a comprehensive review of the utility and potential of IN in the treatment of UC.

METHODS

'Indigo naturalis' 'Qing dai' 'Qingdai' 'Ulcerative colitis' and 'UC' are used as the keywords, and the relevant literature is collected from online databases (Elsevier, PubMed, and Web of Science).

RESULTS AND CONCLUSION

Indirubin, indigo, isatin, tryptanthrin, and β-sitosterol are considered the key components in the treatment of UC with IN. Both preclinical and clinical studies support the efficacy of IN for UC, especially in severe UC or in those who do not respond to or have poor efficacy with existing therapies. The mechanisms of IN for UC are associated with the aryl hydrocarbon receptor pathway activation, immune regulation, oxidative stress inhibition, and intestinal microbial modulation. However, the clinical use of IN has the risks of adverse events such as pulmonary hypertension, which suggests the necessity for its rational application. As a potential therapeutic agent for UC that is currently receiving more attention, the clinical value of IN has been initially demonstrated and warrants further evaluation.

Chimeric antigen receptor T cell therapy for autoimmune disease

Infusion of T cells engineered to express chimeric antigen receptors (CARs) that target B cells has proven to be a successful treatment for B cell malignancies. This success inspired the development of CAR T cells to selectively deplete or modulate the aberrant immune responses that underlie autoimmune disease. Promising results are emerging from clinical trials of CAR T cells targeting the B cell protein CD19 in patients with B cell-driven autoimmune diseases. Further approaches are being designed to extend the application and improve safety of CAR T cell therapy in the setting of autoimmunity, including the use of chimeric autoantibody receptors to selectively deplete autoantigen-specific B cells and the use of regulatory T cells engineered to express antigen-specific CARs for targeted immune modulation. Here, we highlight important considerations, such as optimal target cell populations, CAR construct design, acceptable toxicities and potential for lasting immune reset, that will inform the eventual safe adoption of CAR T cell therapy for the treatment of autoimmune diseases.

Acid-degradable lipid nanoparticles enhance the delivery of mRNA

Lipid nanoparticle (LNP)-mRNA complexes are transforming medicine. However, the medical applications of LNPs are limited by their low endosomal disruption rates, high toxicity and long tissue persistence times. LNPs that rapidly hydrolyse in endosomes (RD-LNPs) could solve the problems limiting LNP-based therapeutics and dramatically expand their applications but have been challenging to synthesize. Here we present an acid-degradable linker termed 'azido-acetal' that hydrolyses in endosomes within minutes and enables the production of RD-LNPs. Acid-degradable lipids composed of polyethylene glycol lipids, anionic lipids and cationic lipids were synthesized with the azido-acetal linker and used to generate RD-LNPs, which significantly improved the performance of LNP-mRNA complexes in vitro and in vivo. Collectively, RD-LNPs delivered mRNA more efficiently to the liver, lung, spleen and brains of mice and to haematopoietic stem and progenitor cells in vitro than conventional LNPs. These experiments demonstrate that engineering LNP hydrolysis rates in vivo has great potential for expanding the medical applications of LNPs.

Human IL-22 receptor-targeted small protein antagonist suppress murine DSS-induced colitis

BACKGROUND

Human interleukin-22 (IL-22) is known as a "dual function" cytokine that acts as a master regulator to maintain homeostasis, structural integrity of the intestinal epithelial barrier, and shielding against bacterial pathogens. On the other hand, the overexpression of IL-22 is associated with hyper-proliferation and recruitment of pathologic effector cells, leading to tissue damage and chronic inflammation in specific diseases including inflammatory bowel disease (IBD). To study a role of IL-22-mediated signaling axis during intestinal inflammation, we generated a set of small protein blockers of IL-22R1 and verified their inhibitory potential on murine model of colitis.

METHODS

We used directed evolution of proteins to identify binders of human IL-22 receptor alpha (IL-22R1), designated as ABR ligands. This approach combines the assembly of a highly complex combinatorial protein library derived from small albumin-binding domain scaffold and selection of promising protein variants using ribosome display followed by large-scale ELISA screening. The binding affinity and specificity of ABR variants were analyzed on transfected HEK293T cells by flow cytometry and LigandTracer. Inhibitory function was further verified by competition ELISA, HEK-Blue IL-22 reporter cells, and murine dextran sulfate sodium (DSS)-induced colitis.

RESULTS

We demonstrate that ABR specifically recognizes transgenic IL-22R1 expressed on HEK293T cells and IL-22R1 on TNFα/IFNγ-activated HaCaT cells. Moreover, some ABR binders compete with the IL-22 cytokine and function as IL-22R1 antagonists in HEK-Blue IL22 reporter cells. In a murine model of DSS-induced acute intestinal inflammation, daily intraperitoneal administration of the best IL-22R1 antagonist, ABR167, suppressed the development of clinical and histological markers of colitis including prevention of mucosal inflammation and architecture deterioration. In addition, ABR167 reduces the DSS-induced increase in mRNA transcript levels of inflammatory cytokines such as IL-1β, IL-6, IL-10, and IL-17A.

CONCLUSIONS

We developed small anti-human IL-22R1 blockers with antagonistic properties that ascertain a substantial role of IL-22-mediated signaling in the development of intestinal inflammation. The developed ABR blockers can be useful as a molecular clue for further IBD drug development.

Discrete interplay of gut microbiota L-tryptophan metabolites in host biology and disease

The gut microbiota and the host maintain a conjoint relationship and together achieve optimal physiology via a multitude of interactive signalling cues. Dietary-derived L-tryptophan (L-trp) is enzymatically metabolized by the resident symbiotic gut microbiota to indole and various indole derivatives. Indole and indole metabolites secreted by the gut bacteria act locally in the intestinal cells as well as distally and modulate tissue-specific functions which are beneficial to the host. Functions attributed to these microbial indole metabolites in the host include regulation of intestinal permeability, immunity and mucosal roles, inflammation, and insulin sensitivity. On the other hand, dysregulation of gut microbiota L-trp metabolism compromises the optimal availability of indole and indole metabolites and can induce the onset of metabolic disorders, inflammation, liver steatosis, and decrease gut barrier integrity. Gut dysbiosis is regarded as one of the prime reasons for this deregulated microbial-derived indole metabolites. A number of indole metabolites from the gut bacteria have been identified recently displaying variable affinity towards xenobiotic nuclear receptors. Microbial metabolite mimicry concept can be used to design and develop novel indole-moiety-containing compounds with higher affinity towards the receptors and efficacy in preclinical studies. Such compounds may serve as therapeutic drugs in clinical trials in the future. In this article, I review L-trp metabolism in the host and gut microbiota and the various physiological functions, patho-physiologies associated with the microbial-released indole metabolites in the host, including the metabolite mimicry-based concept to develop tailored indole-containing novel experimental drugs.

Innate and Adaptive Immune Responses in Intestinal Transplant Rejection: Through the Lens of Inflammatory Bowel and Intestinal Graft-Versus-Host Diseases

Intestinal transplantation is a life-saving procedure utilized for patients failing total parenteral nutrition. However, intestinal transplantattion remains plagued with low survival rates and high risk of allograft rejection. The authors explore roles of innate (macrophages, natural killer cells, innate lymphoid cells) and adaptive immune cells (Th1, Th2, Th17, Tregs) in inflammatory responses, particularly inflammatory bowel disease and graft versus host disease, and correlate these findings to intestinal allograft rejection, highlighting which effectors exacerbate or suppress intestinal rejection. Better understanding of this immunology can open further investigation into potential biomolecular targets to develop improved therapeutic treatment options and immunomonitoring techniques to combat allograft rejection and enhance patient lives.

A comprehensive immunobiology review of IBD: With a specific glance to Th22 lymphocytes development, biology, function, and role in IBD

The two primary forms of inflammatory disorders of the small intestine andcolon that make up inflammatory bowel disease (IBD) are ulcerative colitis (UC) and Crohn's disease (CD). While ulcerative colitis primarily affects the colon and the rectum, CD affects the small and large intestines, as well as the esophagus,mouth, anus, andstomach. Although the etiology of IBD is not completely clear, and there are many unknowns about it, the development, progression, and recurrence of IBD are significantly influenced by the activity of immune system cells, particularly lymphocytes, given that the disease is primarily caused by the immune system stimulation and activation against gastrointestinal (GI) tract components due to the inflammation caused by environmental factors such as viral or bacterial infections, etc. in genetically predisposed individuals. Maintaining homeostasis and the integrity of the mucosal barrier are critical in stopping the development of IBD. Specific immune system cells and the quantity of secretory mucus and microbiome are vital in maintaining this stability. Th22 cells are helper T lymphocyte subtypes that are particularly important for maintaining the integrity and equilibrium of the mucosal barrier. This review discusses the most recent research on these cells' biology, function, and evolution and their involvement in IBD.

Essential oils ameliorate the intestinal damages induced by nonylphenol exposure by modulating tryptophan metabolism and activating aryl hydrocarbon receptor via gut microbiota regulation

Nonylphenol (NP) is a ubiquitous endocrine disruptor that persists in the environment and can significantly contribute to serious health hazards, particularly intestinal barrier injury. Plant essential oils (EOs) have recently gained widespread interest due to their potential for improving intestinal health. However, the precise mechanism and protective effects of EOs ameliorating the intestinal damages induced by NP exposure remain unclear. To clarify the potential mechanism and protective impact of EOs against intestinal injury induced by NP, a total of 144 one-day-old male ducks were randomly allocated to four groups: CON (basal diet), EO (basal diet + 200 mg/kg EOs), NP (basal diet + 40 mg/kg NP), and NPEO (basal diet + 200 mg/kg EOs + 40 mg/kg NP). The data revealed that NP exposure significantly damaged intestinal barrier, as evidenced by a reduction in the levels of tight junction gene expression and an increase in intestinal permeability. Additionally, it disturbed gut microbiota, as well as interfered with tryptophan (Trp) metabolism. The NP-induced disorder of Trp metabolism restrained the activation of aryl hydrocarbon receptor (AhR) and resulted in decreased the expression levels of CYP1A1, IL-22, and STAT3 genes, which were alleviated after treatment with EOs. Taken together, NP exposure resulted in impairment of the intestinal barrier function, disruption of gut microbiota, and disturbances in Trp metabolism. Dietary EOs supplementation alleviated the intestinal barrier injury induced by NP through the Trp/AhR/IL-22 signaling pathway.

Identification and functional characterization of interleukin-22 (IL-22) in orange-spotted grouper (Epinephelus coioides)

In mammals, IL-22 is considered as a critical cytokine regulating of immunity and homeostasis at barrier surfaces. Although IL-22 have been functional characterization in different species of fish, the studies about distinct responses of IL-22 in different organs/tissues/cell types is rather limited. Here, we identified and cloned IL-22 gene (named as Ec-IL-22) from grouper (Epinephelus coioides). Ec-IL-22 gene was detected in all orangs/tissues examined, and was induced in intestine, gill, spleen, head kidney, and primary head kidney/intestine leukocytes following the stimulation of LPS and poly (I:C), as well as Vibrio harveyi and Singapore grouper iridovirus infection (SGIV). In addition, the stimulation of DSS could induce the expression of Ec-IL-22 in intestine and primary leukocytes from intestine. Importantly, the treatment of recombinant Ec-IL-22 induced the mRNA level of proinflammatory cytokines in primary intestine/head kidney leukocytes. The present results improve the understanding of expression patterns and functional characteristics of fish IL-22 in different organs/tissues/cell types.

IL-22 promotes occludin expression by activating autophagy and treats ulcerative colitis

IL-22 serves a protective function in the intestinal barrier. These protective properties of IL-22 may offer a potential treatment for ulcerative colitis (UC). However, the exact mechanisms of action remain unclear. Autophagy plays an important protective role in stabilizing the intestinal barrier. We aimed to explore the role of autophagy in the IL-22-mediated-protective effects in UC. Dextran sulfate sodium (DSS) was administrated via drinking water over 7 days to induce acute UC in BALB/c mice. Treatments with IL-22 (0.25 μg/10 g bodyweight) were started by intraperitoneal injection on days 1, 3, and 5. Weight, disease activity index, histological score, and myeloperoxidase (MPO) activity were used to evaluate the severity of colitis. The expressions of occludin and autophagy-related proteins LC3BII/I were measured by western blot analysis. The lipopolysaccharide-induced HT-29 cell model was used to explore the mechanism. In vivo, IL-22 significantly alleviated DSS-induced clinical manifestations, reduced histological injury, and inhibited MPO activity. IL-22 upregulated the expression of occludin and the LC3B II/I ratio in the colon. In vitro, IL-22 significantly lowered TNF-α levels and enhanced the expression of occludin and the LC3B II/I ratio. Importantly, inhibiting autophagy in vitro by 3-Methyladenine (3-MA) attenuated the occludin protective effects of IL-22. In summary, our findings demonstrate that IL-22 ameliorates DSS-induced ulcerative colitis, which may be attributable to activating autophagy and then promoting occludin expression.

The role of Interleukin-22 in severe acute pancreatitis

Severe acute pancreatitis (SAP) begins with premature activation of enzymes, promoted by the immune system, triggering a potential systemic inflammatory response that leads to organ failure with increased mortality and a bleak prognosis. Interleukin-22 (IL-22) is a cytokine that may have a significant role in SAP. IL-22, a member of the IL-10 cytokine family, has garnered growing interest owing to its potential tissue-protective properties. Recently, emerging research has revealed its specific effects on pancreatic diseases, particularly SAP. This paper provides a review of the latest knowledge on the role of IL-22 and its viability as a therapeutic target in SAP.

Targeting the "tumor microenvironment": RNA-binding proteins in the spotlight in colorectal cancer therapy

Colorectal cancer (CRC) is the third most common cancer and has the second highest mortality rate among cancers. The development of CRC involves both genetic and epigenetic abnormalities, and recent research has focused on exploring the ex-transcriptome, particularly post-transcriptional modifications. RNA-binding proteins (RBPs) are emerging epigenetic regulators that play crucial roles in post-transcriptional events. Dysregulation of RBPs can result in aberrant expression of downstream target genes, thereby affecting the progression of colorectal tumors and the prognosis of patients. Recent studies have shown that RBPs can influence CRC pathogenesis and progression by regulating various components of the tumor microenvironment (TME). Although previous research on RBPs has primarily focused on their direct regulation of colorectal tumor development, their involvement in the remodeling of the TME has not been systematically reported. This review aims to highlight the significant role of RBPs in the intricate interactions within the CRC tumor microenvironment, including tumor immune microenvironment, inflammatory microenvironment, extracellular matrix, tumor vasculature, and CRC cancer stem cells. We also highlight several compounds under investigation for RBP-TME-based treatment of CRC, including small molecule inhibitors such as antisense oligonucleotides (ASOs), siRNAs, agonists, gene manipulation, and tumor vaccines. The insights gained from this review may lead to the development of RBP-based targeted novel therapeutic strategies aimed at modulating the TME, potentially inhibiting the progression and metastasis of CRC.

Neutrophils Mediate Protection Against Colitis and Carcinogenesis by Controlling Bacterial Invasion and IL22 Production by γδ T Cells

Neutrophils are the most abundant leukocytes in human blood and play a primary role in resistance against invading microorganisms and in the acute inflammatory response. However, their role in colitis and colitis-associated colorectal cancer is still under debate. This study aims to dissect the role of neutrophils in these pathologic contexts by using a rigorous genetic approach. Neutrophil-deficient mice (Csf3r-/- mice) were used in classic models of colitis and colitis-associated colorectal cancer and the role of neutrophils was assessed by histologic, cellular, and molecular analyses coupled with adoptive cell transfer. We also performed correlative analyses using human datasets. Csf3r-/- mice showed increased susceptibility to colitis and colitis-associated colorectal cancer compared with control Csf3r+/+ mice and adoptive transfer of neutrophils in Csf3r-/- mice reverted the phenotype. In colitis, Csf3r-/- mice showed increased bacterial invasion and a reduced number of healing ulcers in the colon, indicating a compromised regenerative capacity of epithelial cells. Neutrophils were essential for γδ T-cell polarization and IL22 production. In patients with ulcerative colitis, expression of CSF3R was positively correlated with IL22 and IL23 expression. Moreover, gene signatures associated with epithelial-cell development, proliferation, and antimicrobial response were enriched in CSF3Rhigh patients. Our data support a model where neutrophils mediate protection against intestinal inflammation and colitis-associated colorectal cancer by controlling the intestinal microbiota and driving the activation of an IL22-dependent tissue repair pathway.

Lactococcus lactis as an Interleukin Delivery System for Prophylaxis and Treatment of Inflammatory and Autoimmune Diseases

Target delivery of therapeutic agents with anti-inflammatory properties using probiotics as delivery and recombinant protein expression vehicles is a promising approach for the prevention and treatment of many diseases, such as cancer and intestinal immune disorders. Lactococcus lactis, a Lactic Acid Bacteria (LAB) widely used in the dairy industry, is one of the most important microorganisms with GRAS status for human consumption, for which biotechnological tools have already been developed to express and deliver recombinant biomolecules with anti-inflammatory properties. Cytokines, for  example, are immune system communication molecules present at virtually all levels of the immune response. They are essential in cellular and humoral processes, such as hampering inflammation or adjuvating in the adaptive immune response, making them good candidates for therapeutic approaches. This review discusses the advances in the development of new therapies and prophylactic approaches using LAB to deliver/express cytokines for the treatment of inflammatory and autoimmune diseases in the future.

Challenges and opportunities in inflammatory bowel disease: from current therapeutic strategies to organoid-based models

BACKGROUND

Inflammatory bowel disease (IBD) is an increasingly prevalent global health concern that has garnered substantial attention. However, the underlying mechanisms are still unclear and the current treatments have significant limitations. Intestinal organoids provide an in vitro model to explore the pathogenesis, test the therapeutic effects, and develop regenerative treatments as well as offer the potential to transform drug discovery of IBD.

METHODS

To advance our understanding of the whole story of IBD spanning from the pathogenesis to the current therapeutic strategies and latest advancements, a comprehensive search of major databases including PubMed, Scopus, and Web of Science was conducted to retrieve original articles and reviews related to IBD, organoids, pathogenesis and therapy.

RESULTS

This review deciphers the etiopathogenesis and the current therapeutic approaches in the treatment of IBD. Notably, critical aspects of intestinal organoids in IBD, such as their potential applications, viability, cell renewal ability, and barrier functionality are highlighted. We also discuss the advances, limitations, and prospects of intestinal organoids for precision medicine.

CONCLUSION

The latest strides made in research about intestinal organoids help elucidate intricate aspects of IBD pathogenesis, and pave the prospective avenues for novel therapeutic interventions.

Selenium Yeast Alleviates Dextran Sulfate Sodium-Induced Chronic Colitis in Mice by Reducing Proinflammatory Cytokines and Regulating the Gut Microbiota and Their Metabolites

Background

Inflammatory bowel disease (IBD) is a chronic recurrent gastrointestinal inflammatory disease. Selenium has been reported to have therapeutic potential in IBD. Selenium yeast is a common selenium supplement that is convenient to access. This study explored the effect of selenium yeast on dextran sulfate sodium- (DSS-)induced chronic colitis in mice.

Methods

Mice were randomly divided into four groups: the control group, selenium yeast group, chronic colitis group, and chronic colitis+selenium yeast group (n=6). Mice were killed on the 26th day. The disease activity index (DAI) score and histological damage score were calculated. Cytokines, serum selenium, colonic tissue selenium, gut microbiota and their metabolites short-chain fatty acids (SCFAs) were evaluated.

Results

Selenium yeast lowered IL-1β, IL-6, TNF-α, IL-17A, IL-22 and IFN-γ (P<0.05). In addition, selenium yeast significantly elevated Turicibacter, Bifidobacterium, Allobaculum, Prevotella, Halomonas, Adlercreutzia (P<0.05), and butyric acid (P<0.05).

Conclusion

Selenium yeast could improve DSS-induced chronic colitis in mice by regulating cytokines, gut microbiota and their metabolites.

Bactericidal/permeability-increasing protein instructs dendritic cells to elicit Th22 cell response

Neutrophil-derived bactericidal/permeability-increasing protein (BPI) is known for its bactericidal activity against gram-negative bacteria and neutralization of lipopolysaccharide. Here, we define BPI as a potent activator of murine dendritic cells (DCs). As shown in GM-CSF-cultured, bone-marrow-derived cells (BMDCs), BPI induces a distinct stimulation profile including IL-2, IL-6, and tumor necrosis factor expression. Conventional DCs also respond to BPI, while M-CSF-cultivated or peritoneal lavage macrophages do not. Subsequent to BPI stimulation of BMDCs, CD4+ T cells predominantly secrete IL-22 and, when naive, preferentially differentiate into T helper 22 (Th22) cells. Congruent with the tissue-protective properties of IL-22 and along with impaired IL-22 induction, disease severity is significantly increased during dextran sodium sulfate-induced colitis in BPI-deficient mice. Importantly, physiological diversification of intestinal microbiota fosters BPI-dependent IL-22 induction in CD4+ T cells derived from mesenteric lymph nodes. In conclusion, BPI is a potent activator of DCs and consecutive Th22 cell differentiation with substantial relevance in intestinal homeostasis.

Unlocking the secrets: exploring the influence of the aryl hydrocarbon receptor and microbiome on cancer development

Gut microbiota regulates various aspects of human physiology by producing metabolites, metabolizing enzymes, and toxins. Many studies have linked microbiota with human health and altered microbiome configurations with the occurrence of several diseases, including cancer. Accumulating evidence suggests that the microbiome can influence the initiation and progression of several cancers. Moreover, some microbiotas of the gut and oral cavity have been reported to infect tumors, initiate metastasis, and promote the spread of cancer to distant organs, thereby influencing the clinical outcome of cancer patients. The gut microbiome has recently been reported to interact with environmental factors such as diet and exposure to environmental toxicants. Exposure to environmental pollutants such as polycyclic aromatic hydrocarbons (PAHs) induces a shift in the gut microbiome metabolic pathways, favoring a proinflammatory microenvironment. In addition, other studies have also correlated cancer incidence with exposure to PAHs. PAHs are known to induce organ carcinogenesis through activating a ligand-activated transcriptional factor termed the aryl hydrocarbon receptor (AhR), which metabolizes PAHs to highly reactive carcinogenic intermediates. However, the crosstalk between AhR and the microbiome in mediating carcinogenesis is poorly reviewed. This review aims to discuss the role of exposure to environmental pollutants and activation of AhR on microbiome-associated cancer progression and explore the underlying molecular mechanisms involved in cancer development.

Hyaluronic Acid-Conjugated Thermoresponsive Polymer-Based Bioformulation Enhanced Wound Healing and Gut Barrier Repair of a TNBS-Induced Colitis Injury Ex Vivo Model in a Dynamic Perfusion Device

Impairment of intestinal epithelium is a typical feature of inflammatory bowel disease (IBD) that causes leakage of bacteria and antigens from the intestinal lumen and thus results in persistent immune activation. Hence, healing and regeneration of the damaged gut mucosa is a promising therapeutic approach to achieve deep remission in IBD. Currently, available systemic therapies have moderate effects and are often associated with numerous side effects and malignancies. In this study, we aimed to develop a topical therapy by chemically conjugating a temperature-responsive polymer, i.e., poly(N-isopropylacrylamide), along with hyaluronic acid to obtain a sprayable therapeutic formulation that upon colon instillation adheres to the damaged gut mucosa due to its temperature-induced phase transition and mucoadhesive properties. An ex vivo adhesion experiment demonstrates that this therapeutic formulation forms a thin physical coating on the mucosal lining at a physiological temperature within 5 min. Physicochemical characterization of (P(NIPAM-co-NTBAM)-HA) established this formulation to be biocompatible, hemo-compatible, and non-immunogenic. Prednisolone was encapsulated within the polymer formulation to achieve maximum therapeutic efficacy in the case of IBD-like conditions as assessed in a custom-fabricated perfusion-based ex vivo model system. Histological analysis suggests that the prednisolone-encapsulated polymer formulation nearly restored the mucosal architecture after 2,4,6-trinitrobenzenesulfonic acid-induced damage. Furthermore, a significant (p ≤ 0.001) increase in mRNA levels of Muc-2 and ZO-1 in treated groups further confirmed the mucosal epithelial barrier restoration.

The Hazards of Probiotics on Gut-Derived Pseudomonas aeruginosa Sepsis in Mice Undergoing Chemotherapy

Pseudomonas aeruginosa (P. aeruginosa) is a leading cause of nosocomial infections associated with a high mortality rate and represents a serious threat to human health and the increasing frequency of antimicrobial resistance. Cancer patients are more vulnerable to invasive infection due to ulcerative lesions in mucosal surfaces and immune suppression secondary to chemotherapy. In our in vitro study, we observed that probiotics have the potential to yield beneficial effects on intestinal epithelial cells infected with P. aeruginosa. Additionally, probiotics were found to confer advantageous effects on the innate immunity of mice suffering from Salmonella-induced colitis. As a result, we sought to investigate the impact of probiotics on gut-derived P. aeruginosa sepsis induced by chemotherapy. Following chemotherapy, gut-derived P. aeruginosa sepsis was induced in female C57BL/6 mice aged 6-8 weeks, which were raised under specific-pathogen-free (SPF) conditions in an animal center. Prior to the induction of the sepsis model, the mice were administered 1 × 108 colony-forming units (CFU) of the probiotics, namely Lactobacillus rhamnosus GG (LGG) and Bifidobacterium longum (BL) via oral gavage. We observed that LGG or BL amplified the inflammatory mRNA expression in mice undergoing chemotherapy and suffering from gut-derived P. aeruginosa sepsis. This led to a heightened severity of colitis, as indicated by histological examination. Meanwhile, there was a notable decrease in the expression of antimicrobial peptide mRNA along with reduced levels of zonulin and claudin-2 protein staining within mucosal tissue. These alterations facilitated the translocation of bacteria to the liver, spleen, and bloodstream. To our astonishment, the introduction of probiotics exacerbated gut-derived P. aeruginosa sepsis in mice undergoing chemotherapy. Conclusively, we must be prudent when using probiotics in mice receiving chemotherapy complicated with gut-derived P. aeruginosa sepsis.

Fermented rice bran supplementation attenuates colonic injury through modulating intestinal aryl hydrocarbon receptor and innate lymphoid cells in mice with dextran sodium sulfate-induced acute colitis

This study investigated the effects of fermented rice bran (FRB) on modulating intestinal aryl hydrocarbon receptor (AhR) expression, innate lymphoid cell (ILC)3 populations, the fecal microbiota distribution, and their associations with dextran sodium sulfate (DSS)-induced acute colitis. C57BL/6 mice were assigned to four groups: 1) NC group, normal mice fed the AIN-93M diet; 2) FRB group, normal mice fed a diet supplemented with 5% FRB; 3) NCD group, DSS-treated mice fed AIN-93M; 4) FRBD group, DSS-treated mice fed a 5% FRB-supplemented diet. DSS was administered for 5 d and followed by 5 d for recovery. At the end of the experiment, mice were sacrificed. Their blood and intestinal tissues were collected. Results showed that there were no differences in colonic biological parameters and function between the NC and FRB groups. Similar fecal microbiota diversity was noted between these two groups. Compared to the non-DSS-treated groups, DSS administration led to increased intestinal permeability, enhanced inflammatory cytokine production and disease severity, whereas tight junctions and AhR, interleukin (IL)-22 expressions were downregulated, and the ILC3 population had decreased. Also, gut microbiota diversity differs from the non-DSS-treated groups and more detrimental bacterial populations exist when compared to the FRBD group. FRB supplementation in DSS-treated mice attenuated fecal microbial dysbiosis, decreased intestinal permeability, improved the barrier integrity, upregulated AhR and IL-22 expression, maintained the ILC3 population, and pathologically mitigated colonic injury. These findings suggest enhanced ILC3- and AhR-mediated functions may be partly responsible for the anti-colitis effects of FRB supplementation in DSS-induced colitis.

Indigo naturalis (Qing dai) for inflammatory bowel disease: A systematic review and meta-analysis

BACKGROUND

Indigo naturalis (Qing dai) is a traditional therapy reported to be useful in inflammatory bowel disease (IBD), especially for ulcerative colitis. We performed a systematic review of its efficacy and safety in IBD.

METHODS

Electronic databases (Pubmed, Embase, and Scopus) were searched on 4th March 2023 to identify reports about the use of indigo naturalis in IBD. We extracted data with respect to clinical response, remission, endoscopic and histological responses, and adverse events with the use of indigo naturalis in IBD. Pooled clinical response rates and remission rates were calculated. The quality of studies was assessed using Joanna-Briggs tools.

RESULTS

Nine studies reporting on 299 patients were included. The pooled clinical response rate was 0.796 (95 %CI, 0.7465-0.8379, I2=0), and the clinical remission rate in ulcerative colitis was 0.668 (0.488- 0.809, I2=85.2 %). The pooled relative risk of clinical response was higher in the indigo naturalis group as compared to placebo in the two randomized trials [3.82 (2.04; 7.14, I2=0)]. Except for one reversible pulmonary arterial hypertension case, most reported adverse effects were mild. The endoscopic and histological responses, when reported, suggested that indigo naturalis is effective for ulcerative colitis. The limitations of the systematic review included a small number of randomized studies, reports only from East Asia and a relatively small number of patients, especially for Crohn's disease.

CONCLUSION

Indigo naturalis is effective in the treatment of ulcerative colitis. Future studies should evaluate the comparative efficacy with other drugs.

Pro-osteogenic role of interleukin-22 in calcific aortic valve disease

BACKGROUND AND AIMS

Although calcific aortic valve disease (CAVD) is a common valvular disease among elderly populations and its incidence has markedly increased in recent decades, the pathogenesis of CAVD remains unclear. In this study, we explored the potential role of interleukin (IL)-22 and the underlying molecular mechanism in CAVD.

METHODS AND RESULTS

Our results showed that IL-22 was upregulated in calcific aortic valves from CAVD patients, and its main sources were CD3+ T cells and CD68+ macrophages. Human aortic valve interstitial cells (VICs) expressed the IL-22-specific receptor IL-22R1, and IL-22R1 expression also was elevated in calcified valves. Treatment of cultured human VICs with recombinant human IL-22 resulted in markedly increased expression of osteogenic proteins Runt-related transcription factor 2 (RUNX2) and alkaline phosphatase (ALP), as well as increased matrix calcium deposition. Moreover, siRNA silencing of IL-22R1 blocked the pro-osteogenic effect of IL-22 in VICs. In IL-22-treated VICs, we also observed increased phosphorylation of JAK3 and STAT3 and nuclear translocation of STAT3. Pretreatment with a specific JAK3 inhibitor, WHIP-154, or siRNA knockout of STAT3 effectively mitigated the IL-22-induced osteoblastic trans-differentiation of human VICs.

CONCLUSIONS

Together, these data indicate that IL-22 promotes osteogenic differentiation of VICs by activating JAK3/STAT3 signaling. Based on our results demonstrating a pro-osteogenic role of IL-22 in human aortic valves, pharmacological inhibition of IL-22 signaling may represent a potential strategy for alleviating CAVD.

Cytokine induced inflammatory bowel disease model using organ-on-a-chip technology

Over 2 million people in North America suffer from inflammatory bowel disease (IBD), a chronic and idiopathic inflammatory condition. While previous research has primarily focused on studying immune cells as a cause and therapeutic target for IBD, recent findings suggest that non-immune cells may also play a crucial role in mediating cytokine and chemokine signaling, and therefore IBD symptoms. In this study, we developed an organ-on-a-chip co-culture model of Caco2 epithelial and HUVEC endothelial cells and induced inflammation using pro-inflammatory cytokines TNF-α and IFN-γ. We tested different concentration ranges and delivery orientations (apical vs. basal) to develop a consistently inducible inflammatory response model. We then measured pro-inflammatory cytokines and chemokines IL-6, IL-8, and CXCL-10, as well as epithelial barrier integrity. Our results indicate that this model 1. induces IBD-like cytokine secretion in non-immune cells and 2. decreases barrier integrity, making it a feasible and reliable model to test the direct actions of potential anti-inflammatory therapeutics on epithelial and endothelial cells.

A Narrative Review of Cytokine Networks: Pathophysiological and Therapeutic Implications for Inflammatory Bowel Disease Pathogenesis

Inflammatory bowel disease (IBD) is a lifelong inflammatory immune mediated disorder, encompassing Crohn's disease (CD) and ulcerative colitis (UC); however, the cause and specific pathogenesis of IBD is yet incompletely understood. Multiple cytokines produced by different immune cell types results in complex functional networks that constitute a highly regulated messaging network of signaling pathways. Applying biological mechanisms underlying IBD at the single omic level, technologies and genetic engineering enable the quantification of the pattern of released cytokines and new insights into the cytokine landscape of IBD. We focus on the existing literature dealing with the biology of pro- or anti-inflammatory cytokines and interactions that facilitate cell-based modulation of the immune system for IBD inflammation. We summarize the main roles of substantial cytokines in IBD related to homeostatic tissue functions and the remodeling of cytokine networks in IBD, which may be specifically valuable for successful cytokine-targeted therapies via marketed products. Cytokines and their receptors are validated targets for multiple therapeutic areas, we review the current strategies for therapeutic intervention and developing cytokine-targeted therapies. New biologics have shown efficacy in the last few decades for the management of IBD; unfortunately, many patients are nonresponsive or develop therapy resistance over time, creating a need for novel therapeutics. Thus, the treatment options for IBD beyond the immune-modifying anti-TNF agents or combination therapies are expanding rapidly. Further studies are needed to fully understand the immune response, networks of cytokines, and the direct pathogenetic relevance regarding individually tailored, safe and efficient targeted-biotherapeutics.

A family with ulcerative colitis maps to 7p21.1 and comprises a region with regulatory activity for the aryl hydrocarbon receptor gene

We have mapped a locus on chromosome 7p22.3-7p15.3 spanning a 22.4 Mb region for ulcerative colitis (UC) by whole genome linkage analyses of a large Danish family. The family represent three generations with UC segregating as an autosomal dominant trait with variable expressivity. The whole-genome scan resulted in a logarithm of odds score (LOD score) of Z = 3.31, and a whole genome sequencing (WGS) of two affected excluded disease-causing mutations in the protein coding genes. Two rare heterozygote variants, rs182281985:G>A and rs541426369:G>A, both with low allele frequencies (MAF A:0.0001, gnomAD ver3.1.2), were found in clusters of ChiP-seq transcription factors binding sites close to the AHR (aryl hydrocarbon receptor) gene and the UC associated SNP rs1077773:G>A. Testing the two SNPs in a promoter reporter assay for regulatory activity revealed that rs182281985:G>A influenced the AHR promoter. These results suggest a regulatory region that include rs182281985:G>A close to the UC GWAS SNP rs1077773:G>A and further demonstrate evidence that the AHR gene on the 7p-tel region is a candidate susceptible gene for UC.

Role of tryptophan metabolism in inflammatory bowel disease

Inflammatory bowel disease (IBD) is comprised of ulcerative colitis and Crohn's disease, the pathogenesis of which is closely related to intestinal flora disorders. Abnormalities in the intestinal microenvironment caused by intestinal flora disorders affect amino acid metabolism. Tryptophan is an essential amino acid, and its metabolites are involved in the regulation of immunity, neuronal function, intestinal homeostasis, etc. The development of IBD disease is accompanied by tryptophan deficiency or metabolic abnormalities. This review focuses on the relationship between the intestinal flora metabolite tryptophan and its metabolites and the occurrence and development of IBD disease, and provides new ideas for future diagnostic methods for predicting IBD disease activity and protocols for treating IBD.

IL-22: Immunity's bittersweet symphony

Epithelial cells play a crucial role in barrier defense. Here, Moniruzzaman et al. (2023. J. Exp. Med.https://doi.org/10.1084/jem.20230106) discovered that interleukin-22 (IL-22) represses MHC class II expression by epithelial cells with an opposite impact on chronic inflammatory disease and viral infection.

Deciphering the role of gut metabolites in non-alcoholic fatty liver disease

Perturbations in microbial abundance or diversity in the intestinal lumen leads to intestinal inflammation and disruption of intestinal membrane which eventually facilitates the translocation of microbial metabolites or whole microbes to the liver and other organs through portal vein. This process of translocation finally leads to multitude of health disorders. In this review, we are going to focus on the mechanisms by which gut metabolites like SCFAs, tryptophan (Trp) metabolites, bile acids (BAs), ethanol, and choline can either cause the development/progression of non-alcoholic fatty liver disease (NAFLD) or serves as a therapeutic treatment for the disease. Alterations in some metabolites like SCFAs, Trp metabolites, etc., can serve as biomarker molecules whereas presence of specific metabolites like ethanol definitely leads to disease progression. Thus, proper understanding of these mechanisms will subsequently help in designing of microbiome-based therapeutic approaches. Furthermore, we have also focussed on the role of dysbiosis on the mucosal immune system. In addition, we would also compile up the microbiome-based clinical trials which are currently undergoing for the treatment of NAFLD and non-alcoholic steatohepatitis (NASH). It has been observed that the use of microbiome-based approaches like prebiotics, probiotics, symbiotics, etc., can act as a beneficial treatment option but more research needs to be done to know how to manipulate the composition of gut microbes.

Interleukin-22 induces immune-related gene expression in the gills of Japanese medaka Oryzias latipes

The cytokine interleukin (IL)-22 has been identified in several fish species; however, its functional significance in the gills of these fish species remains unclear. In this study, we analyzed the expression of proinflammatory cytokines, antimicrobial peptides, and IL-22 binding protein in the gills of wild-type and IL-22-knockout (IL-22 KO) medaka under dextran sulfate sodium-induced inflammation. We also produced medaka recombinant IL-22 (rIL-22) and analyzed the expression of immune-related genes in rIL-22-stimulated primary cell cultures from gills. The il1b, il6, tnfa, and hamp genes were significantly upregulated in wild-type gills upon dextran sulfate sodium stimulation compared with the naïve state but not in IL-22 KO gills. il22bp transcripts were barely detectable in the IL-22 KO medaka gills. However, the expression of il1b, il6, hamp, and il22bp was upregulated in rIL-22-stimulated gill cell culture. These results suggest IL-22 could be involved in immune responses through inflammatory cytokine and antimicrobial peptide production in fish gills.

Modulation of tryptophan metabolism via AHR-IL22 pathway mediates the alleviation of DSS-induced colitis by chitooligosaccharides with different degrees of polymerization

Oral administration of chitooligosaccharides (COS) has been reported to alleviate colitis in mice. However, the mechanism of action of COS with specific polymerization degree on gut inflammation and metabolism remains unclear. This study aimed to investigate the effects of chitobiose (COS2), chitotetraose (COS4), and chitohexaose (COS6) on colitis, and to elucidate their underlying mechanisms. COS2, COS4, and COS6 were able to significantly alleviate colonic injury and inflammation levels. COS6 has the best anti-inflammatory effect. Furthermore, COS6 could down-regulate the level of indoleamine-2,3-dioxygenase1 (IDO1) and restore the levels of indole, indoleacetic-3-acid (IAA), and indole-3-carbaldehyde (I3A) in the cecum of chronic colitis mice (p < 0.05), thereby regulating tryptophan metabolism. In the aromatic hydrocarbon receptor-IL-22 (AHR-IL-22) pathway, although there were differences between chronic colitis and acute colitis mice, COS intervention could restore the AHR-IL-22 pathway to normal, promote the expression of MUC2, and repair the intestinal mucosal barrier. In conclusion, the results of this study suggested that COS had a good inhibitory effect on IDO1 under inflammation and the changes of AHR and IL-22 levels at different stages of disease development. This provides new insights into the potential use of COS as a functional food for improving intestinal inflammation and metabolism.

Maternal polysorbate 80 exposure causes intestinal ILCs and CD4+ T cell developmental abnormalities in mouse offspring

This study aimed to investigate the transgenerational impacts of maternal intake of polysorbate 80 (P80), an emulsifier widely used in modern society, on the development of offspring immunity. Our results revealed that maternal P80 treatment led to impaired differentiation of innate lymphoid cells (ILCs) and CD4+ T cells in the small intestinal lamina propria (SiLP), resulting in intestinal dyshomeostasis in female offspring. Furthermore, we found that SiLP ILCs abundances were significantly altered in 0-day-old fetuses from P80-treated mothers, indicating a prenatal impact of P80-treated mothers on offspring immunity. Additionally, cesarean section and foster-nursing studies demonstrated that P80-induced altered SiLP ILCs in 0-day-old fetuses could further induce dysregulation of ILCs and CD4+ T cells in the SiLP, thus promoting intestinal dysregulation in offspring later in life. Overall, our findings suggest that maternal P80 intake could prenatally program the development of offspring immunity, exerting a significant and long-lasting impact.

Microbiota as key factors in inflammatory bowel disease

Inflammatory Bowel Disease (IBD) is characterized by prolonged inflammation of the gastrointestinal tract, which is thought to occur due to dysregulation of the immune system allowing the host's cells to attack the GI tract and cause chronic inflammation. IBD can be caused by numerous factors such as genetics, gut microbiota, and environmental influences. In recent years, emphasis on commensal bacteria as a critical player in IBD has been at the forefront of new research. Each individual harbors a unique bacterial community that is influenced by diet, environment, and sanitary conditions. Importantly, it has been shown that there is a complex relationship among the microbiome, activation of the immune system, and autoimmune disorders. Studies have shown that not only does the microbiome possess pathogenic roles in the progression of IBD, but it can also play a protective role in mediating tissue damage. Therefore, to improve current IBD treatments, understanding not only the role of harmful bacteria but also the beneficial bacteria could lead to attractive new drug targets. Due to the considerable diversity of the microbiome, it has been challenging to characterize how particular microorganisms interact with the host and other microbiota. Fortunately, with the emergence of next-generation sequencing and the increased prevalence of germ-free animal models there has been significant advancement in microbiome studies. By utilizing human IBD studies and IBD mouse models focused on intraepithelial lymphocytes and innate lymphoid cells, this review will explore the multifaceted roles the microbiota plays in influencing the immune system in IBD.

Impacts of Eimeria coinfection on growth performance, intestinal health and immune responses of broiler chickens

Coccidiosis caused by Eimeria is one of the most severe chicken diseases and imposes huge economic losses to the poultry industry globally. Multi-Eimeria species coinfections are common with the most prevalent combination being mixtures of Eimeria acervulina and Eimeria tenella. Although detrimental impacts of either E. acervulina or E. tenella on chicken health are well recognized, no information is available regarding their coinfection effects so far. This study was designed to investigate the influence of coinfection with E. acervulina and E. tenella on broiler chickens. 144 one-day-old broiler chickens within each of trials (trial I or II) were divided into four groups, namely, control group (CG), E. acervulina infection group (EAIG), E. tenella infection group (ETIG) and dual (E. acervulina and E. tenella) infection group (DIG). Then, chickens were measured for weight loss, lesion scores, oocyst outputs, histological changes and expressions of pro-inflammatory (interleukin [IL]-6, IL-8 and IL-18), regulatory (IL-10 and IL-22) cytokines and Toll-like receptors (TLR; TLR2 and TLR4) as well as intestinal barrier (mucin 2 [MUC2] and fattey acid-bingding proteins 2 and 6 [FABP2 and FABP6])- and tight junction (TJ; zonula occluden-1 [ZO-1], occludin [OCLN], and claudins 1 and 5 [CLDN1 and CLDN5])-related proteins at 3, 5, 7, 10, 14 and 21 days post-infection, respectively. Our results consistently showed that although ETIG and DIG exhibited a higher level of weight loss and a more amount of oocyst excretion than EAIG, DIG had lighter lesions than EAIG in the early phase because of coinfection with E. tenella. A higher (P < 0.05) ratio of duodenal villous height to crypt depth was also observed in DIG than EAIG. Moreover, histological changes in the duodenum and cecum varied by single and dual Eimeria infections. Expressions of the intestinal barrier- and TJ-related genes of EAIG, ETIG and DIG were significantly (P < 0.05) upregulated but their levels exhibited differential changes among infected chickens. Similarly, the infected chickens showed significant (P < 0.05) inflammatory responses and higher (P < 0.05) expressions of TLRs in the intestines in comparison to CG. These results presented a comprehensive physiological, pathological and immunological characterization of E. acervulina and E. tenella coinfection in broiler chickens and also shed insights into pathogenesis of multi-coccidia coinfections.

Antimicrobial overproduction sustains intestinal inflammation by inhibiting Enterococcus colonization

Loss of antimicrobial proteins such as REG3 family members compromises the integrity of the intestinal barrier. Here, we demonstrate that overproduction of REG3 proteins can also be detrimental by reducing a protective species in the microbiota. Patients with inflammatory bowel disease (IBD) experiencing flares displayed heightened levels of secreted REG3 proteins that mediated depletion of Enterococcus faecium (Efm) from the gut microbiota. Efm inoculation of mice ameliorated intestinal inflammation through activation of the innate immune receptor NOD2, which was associated with the bacterial DL-endopeptidase SagA that generates NOD2-stimulating muropeptides. NOD2 activation in myeloid cells induced interleukin-1β (IL-1β) secretion to increase the proportion of IL-22-producing CD4+ T helper cells and innate lymphoid cells that promote tissue repair. Finally, Efm was unable to protect mice carrying a NOD2 gene variant commonly found in IBD patients. Our findings demonstrate that inflammation self-perpetuates by causing aberrant antimicrobial activity that disrupts symbiotic relationships with gut microbes.

Unlocking the potential of targeting histone-modifying enzymes for treating IBD and CRC

Dysregulation of histone modifications has been implicated in the pathogenesis of both inflammatory bowel disease (IBD) and colorectal cancer (CRC). These diseases are characterized by chronic inflammation, and alterations in histone modifications have been linked to their development and progression. Furthermore, the gut microbiota plays a crucial role in regulating immune responses and maintaining gut homeostasis, and it has been shown to exert effects on histone modifications and gene expression in host cells. Recent advances in our understanding of the roles of histone-modifying enzymes and their associated chromatin modifications in IBD and CRC have provided new insights into potential therapeutic interventions. In particular, inhibitors of histone-modifying enzymes have been explored in clinical trials as a possible therapeutic approach for these diseases. This review aims to explore these potential therapeutic interventions and analyze previous and ongoing clinical trials that examined the use of histone-modifying enzyme inhibitors for the treatment of IBD and CRC. This paper will contribute to the current body of knowledge by exploring the latest advances in the field and discussing the limitations of existing approaches. By providing a comprehensive analysis of the potential benefits of targeting histone-modifying enzymes for the treatment of IBD and CRC, this review will help to inform future research in this area and highlight the significance of understanding the functions of histone-modifying enzymes and their associated chromatin modifications in gastrointestinal disorders for the development of potential therapeutic interventions.

The Bowel-Associated Arthritis-Dermatosis Syndrome (BADAS): A Systematic Review

Bowel-associated arthritis-dermatosis syndrome (BADAS) is a rare neutrophilic dermatosis that was first described in 1971 in patients who underwent bypass surgery for obesity. Over the years, the number of reported cases associated with medical gastroenterological conditions, particularly inflammatory bowel disease (IBD), has progressively increased. To date, there are no systematic reviews in the literature on BADAS. The design of an a priori protocol was based on PRISMA guidelines, and a search of PubMed and Scopus databases was conducted for articles published between 1971 and 2023 related to the topic. Fifty-one articles including 113 patients with BADAS were analyzed in this systematic review. Bariatric surgery and IBD were the most frequently reported causes of BADAS, accounting for 63.7% and 24.7% of all cases, respectively. A total of 85% of cases displayed the typical dermatological presentation, including urticarial maculopapular lesions centered by a vesicopustule, with the majority of lesions located on the upper limbs (73.5%). Polyarthralgia or localized arthritis were always present. Atypical presentations included cellulitis-like, erythema-nodosum-like, Sweet-syndrome-like and pyoderma-gangrenosum-like manifestations. Gastrointestinal symptoms were frequently observed in IBD-related cases (67.9%). The histopathology showed a neutrophilic infiltrate (96.6%). The most commonly used treatment regimens consisted of systemic corticosteroids, metronidazole and tetracyclines, either alone or in combination. A relapsing-remitting course was observed in 52.1% of patients. In conclusion, BADAS is a neutrophilic dermatosis that presents with a wide variety of cutaneous manifestations, both typical and atypical. Gastrointestinal symptoms are frequently observed, particularly in cases related to IBD. The histopathology is clear but not specific compared with other neutrophilic dermatoses. The diagnosis can be challenging, but the relapsing-remitting course and the strong association with polyarthralgia and gastrointestinal disease can aid in the diagnosis.

Aryl hydrocarbon receptor (AHR): towards understanding intestinal microbial ligands including vitamin B12 and folic acid as natural antagonists

AHR has been identified as ligand-modulated transcription factor and environmental sensor. However, explanation of its multiple agonistic and antagonistic ligands is far from complete. Studies of AHR's role in host-microbiome interaction are currently a fruitful area of research. Microbial products and virulence factors have been identified as AHR agonists. In steady state they are involved in safeguarding intestinal barrier integrity. When virulence factors from pathogenic bacteria are identified by AHR of intestinal immune cells, anti-microbial defense mechanisms are activated by generating reactive oxygen species (ROS) in intestinal epithelial cells and recruited immune cells. ROS production has to be strictly controlled, and anti-inflammatory responses have to be initiated timely in the resolution phase of inflammation to avoid tissue damage and chronic inflammatory responses. Surprisingly, bacteria-generated vitamin B12/cobalamin and vitamin B9/folic acid have been identified as natural AHR antagonists, stimulating the interest of biochemists. Hints for AHR-cobalamin antagonism are pointing to cobalamin-dependent enzymes leading to alterations of TCA cycle intermediates, and TCDD-mediated loss of serum cobalamin. Although we are still at the beginning to understand mechanisms, it is likely that scientific efforts are on a rewarding path to understand novel AHR functions.

IL-33's role in the gut immune system: A comprehensive review of its crosstalk and regulation

The intestinal tract is the largest immune organ in the human body, comprising a complex network of immune cells and epithelial cells that perform a variety of functions such as nutrient absorption, digestion, and waste excretion. Maintenance of homeostasis and effective responses to injury in the colonic epithelium are crucial for maintaining homeostasis between these two cell types. The onset and perpetuation of gut inflammation, characterizing inflammatory bowel diseases (IBD), are triggered by constitutive dysregulation of cytokine production. IL-33 is a newly characterized cytokine that has emerged as a critical modulator of inflammatory disorders. IL-33 is constitutively expressed in the nuclei of different cell types such as endothelial, epithelial, and fibroblast-like cells. Upon tissue damage or pathogen encounter, IL-33 is released as an alarmin and signals through a heterodimer receptor that consists of serum Stimulation-2 (ST2) and IL-1 receptor accessory protein (IL-1RAcP). IL-33 has the ability to induce Th2 cytokine production and enhance both Th1 and Th2, as well as Th17 immune responses. Exogenous administration of IL-33 in mice caused pathological changes in most mucosal tissues such as the lung and the gastrointestinal (GI) tract associated with increased production of type 2 cytokines and chemokines. In vivo and in vitro, primary studies have exhibited that IL-33 can activate Th2 cells, mast cells, or basophils to produce type 2 cytokines such as IL-4, IL-5, and IL-13. Moreover, several novel cell populations, collectively referred to as "type 2 innate lymphoid cells," were identified as being IL-33 responsive and are thought to be important for initiating type 2 immunity. Nevertheless, the underlying mechanisms by which IL-33 promotes type 2 immunity in the GI tract remain to be fully understood. Recently, it has been discovered that IL-33 plays important roles in regulatory immune responses. Highly suppressive ST2 + FoxP3+ Tregs subsets regulated by IL-33 were identified in several tissues, including lymphoid organs, gut, lung, and adipose tissues. This review aims to comprehensively summarize the current knowledge on IL-33's role in the gut immune system, its crosstalk, and regulation. The article will provide insights into the potential applications of IL-33-based therapies in the treatment of gut inflammatory disorders.

The Effects of a High-Fat Diet on Inflammatory Bowel Disease

The interactions among diet, intestinal immunity, and microbiota are complex and play contradictory roles in inflammatory bowel disease (IBD). An increasing number of studies has shed light on this field. The intestinal immune balance is disrupted by a high-fat diet (HFD) in several ways, such as impairing the intestinal barrier, influencing immune cells, and altering the gut microbiota. In contrast, a rational diet is thought to maintain intestinal immunity by regulating gut microbiota. In this review, we emphasize the crucial contributions made by an HFD to the gut immune system and microbiota.