IL23 Promotes Antimicrobial Pathways in Human Macrophages, Which Are Reduced With the IBD-Protective IL23R R381Q Variant

Immune modulation for the patterns of epithelial cell death in inflammatory bowel disease

Inflammatory bowel disease (IBD) is an inflammatory disease of the intestine whose primary pathological presentation is the destruction of the intestinal epithelium. The intestinal epithelium, located between the lumen and lamina propria, transmits luminal microbial signals to the immune cells in the lamina propria, which also modulate the intestinal epithelium. In IBD patients, intestinal epithelial cells (IECs) die dysfunction and the mucosal barrier is disrupted, leading to the recruitment of immune cells and the release of cytokines. In this review, we describe the structure and functions of the intestinal epithelium and mucosal barrier in the physiological state and under IBD conditions, as well as the patterns of epithelial cell death and how immune cells modulate the intestinal epithelium providing a reference for clinical research and drug development of IBD. In addition, according to the targeting of epithelial apoptosis and necroptotic pathways and the regulation of immune cells, we summarized some new methods for the treatment of IBD, such as necroptosis inhibitors, microbiome regulation, which provide potential ideas for the treatment of IBD. This review also describes the potential for integrating AI-driven approaches into innovation in IBD treatments.

Charge-based immunoreceptor signalling in health and disease

Immunoreceptors have crucial roles in sensing environmental signals and initiating immune responses to protect the host. Dysregulation of immunoreceptor signalling can therefore lead to a range of diseases, making immunoreceptor-based therapies a promising frontier in biomedicine. A common feature of various immunoreceptors is the basic-residue-rich sequence (BRS), which is a largely unexplored aspect of immunoreceptor signalling. The BRS is typically located in the cytoplasmic juxtamembrane region of immunoreceptors, where it forms dynamic interactions with neighbouring charged molecules to regulate signalling. Loss or gain of the basic residues in an immunoreceptor BRS has been linked to severe human diseases, such as immunodeficiency and autoimmunity. In this Perspective, we describe the role of BRSs in various immunoreceptors, elucidating their signalling mechanisms and biological functions. Furthermore, we highlight pathogenic mutations in immunoreceptor BRSs and discuss the potential of leveraging BRS signalling in engineered T cell-based therapies.

The IL-23R and Its Genetic Variants: A Hitherto Unforeseen Bridge Between the Immune System and Cancer Development

IL-23R (interleukin-23 receptor), found on the surface of several immune cells, plays a key role in the immune system. Indeed, this process is not limited to the inflammatory response but also plays a role in the adaptive immune response. The binding between IL-23R and its specific ligand, the interleukin 23, initiates a number of specific signals by modulating both properties and behavior of immune cells. In particular, it is critical for the regulation of T helper 17 cells (Th17). Th17s are a subset of T cells involved in autoimmune and inflammatory diseases, as well as in cancer. The clinical relevance of IL-23R is underscored by its association with an elevated susceptibility or diminished vulnerability to a spectrum of diseases, including psoriasis, ankylosing spondylitis, and inflammatory bowel disease (IBD). Evidence has emerged that suggests it may also serve to predict both tumor progression and therapeutic responsiveness. It is noteworthy that the IL-23/IL-23R pathway is emerging as a promising therapeutic target. A number of biologic drugs, such as monoclonal antibodies, are currently developing with the aim of blocking this interaction, thus reducing inflammation. This represents a significant advancement in the field of medicine, offering new hope for pursuing more effective and personalized treatments. Recent studies have also investigated the role of such a pathway in autoimmune diseases, and its potential impact on infections as well as in carcinogenesis. The aim of this review is to focus on the role of IL-23R in immune genetics and its potential for modulating the natural history of neoplastic disease.

Human Amniotic MSC Response in LPS-Stimulated Ascites from Patients with Cirrhosis: FOXO1 Gene and Th17 Activation in Enhanced Antibacterial Activation

Spontaneous bacterial peritonitis (SBP) is a severe complication in patients with decompensated liver cirrhosis and is commonly treated with broad spectrum antibiotics. However, the rise of antibiotic resistance requires alternative therapeutic strategies. As recently shown, human amnion-derived mesenchymal stem cells (hA-MSCs) are able, in vitro, to promote bacterial clearance and modulate the immune and inflammatory response in SBP. Our results highlight the upregulation of FOXO1, CXCL5, CXCL6, CCL20, and MAPK13 in hA-MSCs as well as the promotion of bacterial clearance, prompting a shift in the immune response toward a Th17 lymphocyte phenotype after 72 h treatment. In this study, we used an in vitro SBP model and employed omics techniques (next-generation sequencing) to investigate the mechanisms by which hA-MSCs modify the crosstalk between immune cells in LPS-stimulated ascitic fluid. We also validated the data obtained via qRT-PCR, cytofluorimetric analysis, and Luminex assay. These findings provide further support to the hope of using hA-MSCs for the prevention and treatment of infective diseases, such as SBP, offering a viable alternative to antibiotic therapy.

Interleukin 23 receptor: Expression and regulation in immune cells

The importance of IL-23 and its specific receptor, IL-23R, in the pathogenesis of several chronic inflammatory diseases has been established, but the underlying pathological mechanisms are not fully understood. This review focuses on IL-23R expression and regulation in immune cells.

The Role of the Microbiome in the Pathogenesis and Treatment of Ulcerative Colitis-A Literature Review

Ulcerative colitis (UC) is a chronic inflammatory bowel disease affecting the colon and rectum. UC's pathogenesis involves colonic epithelial cell abnormalities and mucosal barrier dysfunction, leading to recurrent mucosal inflammation. The purpose of the article is to show the complex interplay between ulcerative colitis and the microbiome. The literature search was conducted using the PubMed database. After a screening process of studies published before October 2023, a total of 136 articles were selected. It has been discovered that there is a fundamental correlation of a robust intestinal microbiota and the preservation of gastrointestinal health. Dysbiosis poses a grave risk to the host organism. It renders the host susceptible to infections and has been linked to the pathogenesis of chronic diseases, with particular relevance to conditions such as ulcerative colitis. Current therapeutic strategies for UC involve medications such as aminosalicylic acids, glucocorticoids, and immunosuppressive agents, although recent breakthroughs in monoclonal antibody therapies have significantly improved UC treatment. Furthermore, modulating the gut microbiome with specific compounds and probiotics holds potential for inflammation reduction, while fecal microbiota transplantation shows promise for alleviating UC symptoms. This review provides an overview of the gut microbiome's role in UC pathogenesis and treatment, emphasizing areas for further research.

Human MCTS1-dependent translation of JAK2 is essential for IFN-γ immunity to mycobacteria

Human inherited disorders of interferon-gamma (IFN-γ) immunity underlie severe mycobacterial diseases. We report X-linked recessive MCTS1 deficiency in men with mycobacterial disease from kindreds of different ancestries (from China, Finland, Iran, and Saudi Arabia). Complete deficiency of this translation re-initiation factor impairs the translation of a subset of proteins, including the kinase JAK2 in all cell types tested, including T lymphocytes and phagocytes. JAK2 expression is sufficiently low to impair cellular responses to interleukin-23 (IL-23) and partially IL-12, but not other JAK2-dependent cytokines. Defective responses to IL-23 preferentially impair the production of IFN-γ by innate-like adaptive mucosal-associated invariant T cells (MAIT) and γδ T lymphocytes upon mycobacterial challenge. Surprisingly, the lack of MCTS1-dependent translation re-initiation and ribosome recycling seems to be otherwise physiologically redundant in these patients. These findings suggest that X-linked recessive human MCTS1 deficiency underlies isolated mycobacterial disease by impairing JAK2 translation in innate-like adaptive T lymphocytes, thereby impairing the IL-23-dependent induction of IFN-γ.

IL-23/IL-23R Promote Macrophage Pyroptosis and T Helper 1/T Helper 17 Cell Differentiation in Mycobacterial Infection

Pathogen-induced epigenetic modifications can reshape anti-infection immune processes and control the magnitude of host responses. DNA methylation profiling has identified crucial aberrant methylation changes associated with diseases, thus providing biological insights into the roles of epigenetic factors in mycobacterial infection. In this study, we performed a genome-wide methylation analysis of skin biopsies from patients with leprosy and healthy controls. T helper 17 differentiation pathway was found to be significantly associated with leprosy through functional enrichment analysis. As a key gene in this pathway, IL-23R was found to be critical to mycobacterial immunity in leprosy, according to integrated analysis with DNA methylation, RNA sequencing, and GWASs. Functional analysis revealed that IL-23/IL-23R-enhanced bacterial clearance by activating caspase-1/GSDMD-mediated pyroptosis in a manner dependent on NLRP3 through signal transducer and activator of transcription 3 signaling in macrophages. Moreover, IL23/IL-23R promoted T helper 1 and T helper 17 cell differentiation and proinflammatory cytokine secretion, thereby increasing host bactericidal activity. IL-23R knockout attenuated the effects and increased susceptibility to mycobacterial infection mentioned earlier. These findings illustrate the biological functions of IL-23/IL-23R in modulating intracellular bacterial clearance in macrophages and further support their regulatory effects in T helper cell differentiation. Our study highlights that IL-23/IL-23R might serve as potential targets for the prevention and treatment of leprosy and other mycobacterial infections.

IL-12 and IL-23 pathway inhibition in inflammatory bowel disease

Interleukin-12 (IL-12) and interleukin-23 (IL-23), which belong to the IL-12 family of cytokines, have a key role in intestinal homeostasis and inflammation and are implicated in the pathogenesis of inflammatory bowel disease. Upon their secretion by antigen-presenting cells, they exert both pro-inflammatory and anti-inflammatory receptor-mediated effects. An increased understanding of these biological effects, particularly the pro-inflammatory effects mediated by IL-12 and IL-23, has led to the development of monoclonal antibodies that target a subunit common to IL-12 and IL-23 (p40; targeted by ustekinumab and briakinumab), or the IL-23-specific subunit (p19; targeted by risankizumab, guselkumab, brazikumab and mirikizumab). This Review provides a summary of the biology of the IL-12 family cytokines IL-12 and IL-23, discusses the role of these cytokines in intestinal homeostasis and inflammation, and highlights IL-12- and IL-23-directed drug development for the treatment of Crohn's disease and ulcerative colitis.

Targeting IL-23 for IBD: Rationale and Progress to Date

Inflammatory bowel disease, including Crohn's disease and ulcerative colitis, comprises multiple complex immune-mediated disorders. Early diagnosis and prompt disease control may prevent long-term complications and hospitalization. The therapeutic options have expanded in the last two decades, with the development of biologics and small molecules targeting specific pathways implicated in inflammatory bowel disease pathogenesis. The interleukin (IL)-23/Th-17 axis is one such example. Targeting IL-12/23 is effective for the treatment of both moderate-to-severe Crohn's disease and ulcerative colitis, and ustekinumab (an IL-12/23p40 antagonist) is approved for both indications. In patients with psoriasis, improved clinical outcomes were observed with agents that more selectively targeted IL-23 (IL-23p19 antagonists) compared with those that target both IL-12 and IL-23. Many specific IL-23p19 antagonists are currently being investigated in Crohn's disease and ulcerative colitis, and risankizumab has been recently approved for moderate-to-severely active Crohn's disease. In this review, we summarize the mechanisms of action and the evidence from clinical trials supporting the efficacy and safety of IL-23p19 antagonists for the treatment of inflammatory bowel disease.

Comparative functional analysis of macrophage phagocytosis in Dagu chickens and Wenchang chickens

Phagocytosis of macrophages constitutes a powerful barrier to innate immunity. Differences in the phagocytic function of macrophages among chicken breeds have rarely been reported, and the molecular mechanisms underlying phagocytosis remain poorly understood. This study compared functional difference of macrophages in Dagu chickens, originated in Zhuanghe, Liaoning Province, China, and Wenchang chickens, originated from Hainan Island in the South China Sea, and explored the potential molecular mechanisms by integrated analysis of mRNA expression profiles of macrophages and whole genome sequencing. Immunological parameters in peripheral blood indicated that Dagu chickens were more resistant to Salmonella challenge at 28 days old. Phagocytosis index and phagocytosis rate of macrophages displayed Dagu chickens performed a significantly higher phagocytic ability of macrophages at 14 and 28 days old. Furthermore, comparative analysis of mRNA expression profiles of macrophages of two breeds at 28 days old revealed that 1136 differentially expressed genes (DEGs), and 22 DEGs (e.g., H2AFZ, SNRPA1, CUEDC2, S100A12) were found to be hub genes regulating phagocytosis by participating in different immunological biological signaling pathways. In addition, many DEGs and hub genes were under strong differentiation in genome between two breeds, the H2AFZ gene was an intersection of DEGs and hub genes. These results provided a comprehensive functional comparison and transcriptomic profiles of macrophages in Chinese native chicken breeds, and deepened our understanding of the genetic mechanism of innate immunity.

Targeting macrophage autophagy for inflammation resolution and tissue repair in inflammatory bowel disease

Inflammatory bowel disease (IBD) is a chronic, non-specific, recurrent inflammatory disease, majorly affecting the gastrointestinal tract. Due to its unclear pathogenesis, the current therapeutic strategy for IBD is focused on symptoms alleviation. Autophagy is a lysosome-mediated catabolic process for maintaining cellular homeostasis. Genome-wide association studies and subsequent functional studies have highlighted the critical role of autophagy in IBD via a number of mechanisms, including modulating macrophage function. Macrophages are the gatekeepers of intestinal immune homeostasis, especially involved in regulating inflammation remission and tissue repair. Interestingly, many autophagic proteins and IBD-related genes have been revealed to regulate macrophage function, suggesting that macrophage autophagy is a potentially important process implicated in IBD regulation. Here, we have summarized current understanding of macrophage autophagy function in pathogen and apoptotic cell clearance, inflammation remission and tissue repair regulation in IBD, and discuss how this knowledge can be used as a strategy for IBD treatment.

Management of Infections in Psoriatic Patients Treated with Systemic Therapies: A Lesson from the Immunopathogenesis of Psoriasis

Modern treatments continue to be developed based on identifying targets within the innate and adaptive immune pathways associated with psoriasis. Whilst there is a sound biologic rationale for increased risk of infection following treatment with immunomodulators, the clinical evidence is confounded by these agents being used in patients affected with several comorbidities. In an era characterized by an ever greater and growing risk of infections, it is necessary to always be updated on this risk. In this mini-review, we will discuss recent updates in psoriasis immunopathogenesis as a rationale for systemic therapy, outline the risk of infections linked to the disease itself and systemic therapy as well, and provide an overview of the prevention and management of infections.

Chitosan-modified Phellinus igniarius polysaccharide PLGA nanoparticles ameliorated inflammatory bowel disease

In many clinical studies, prebiotics have been used as adjuvant therapy for inflammatory bowel disease (IBD). Phellinus igniarius polysaccharide (PIP) possesses great anti-inflammatory and prebiotic activities. Herein, we developed an orally deliverable PIP-loaded chitosan-modified PLGA nanomedicine (CS-PIPP) to investigate its anti-inflammatory effect in vitro and in vivo. Dextran sodium sulfate (DSS)-induced colitis model was established to evaluate the preventive effect of CS-PIPP on IBD. This study characterized that CS-PIPP had a size of 288.7 ± 5.49 nm, positive zeta potential, and showed good stability over four weeks. The in-vitro study suggested that CS-PIPP had enhanced phagocytosis by macrophages, which could further significantly inhibit M1-like macrophages phenotype and regulate lipopolysaccharide (LPS)-induced inflammatory cytokines. The in-vivo study revealed that CS-PIPP prominently prevented intestinal inflammatory damage and protected the integrity of the intestinal barrier. Moreover, CS-PIPP increased the contents of short-chain fatty acids (SCFAs) and positively regulated the gut microbiota. Specifically, CS-PIPP reduced enteropathogenic microorganisms while increasing the beneficial microbiota, including Lactobacillus and Akkermansia, which revealed the potential of CS-PIPP as prebiotics. Generally, CS-PIPP promoted the anti-inflammatory effect of PIP, so it could be regarded as a novel and potent nanoformulation to treat IBD.

Pseudomonas Aeruginosa Lung Infection Subverts Lymphocytic Responses through IL-23 and IL-22 Post-Transcriptional Regulation

Pseudomonas aeruginosa (P.a) is a pathogen causing significant morbidity and mortality, particularly in hospital patients undergoing ventilation and in individuals with cystic fibrosis. Although we and others have investigated mechanisms used by P.a to subvert innate immunity, relatively less is known about the potential strategies used by this bacterium to fight the adaptive immune system and, in particular, T cells. Here, using RAG KO (devoid of ‘classical’ αβ and γδ TCR T lymphocytes) and double RAG γC KO mice (devoid of T, NK and ILC cells), we demonstrate that the lymphocytic compartment is important to combat P.a (PAO1 strain). Indeed, we show that PAO1 load was increased in double RAG γC KO mice. In addition, we show that PAO1 down-regulates IL-23 and IL-22 protein accumulation in the lungs of infected mice while up-regulating their RNA production, thereby pointing towards a specific post-transcriptional regulatory mechanism not affecting other inflammatory mediators. Finally, we demonstrate that an adenovirus-mediated over-expression of IL-1, IL-23 and IL-7 induced lung neutrophil and lymphocytic influx and rescued mice against P.a-induced lethality in all WT, RAG γC KO and RAG γC KO RAG-deficient mice, suggesting that this regimen might be of value in ‘locally immunosuppressed’ individuals such as cystic fibrosis patients.

Interleukin-23 in the Pathogenesis of Inflammatory Bowel Disease and Implications for Therapeutic Intervention

The interleukin-23 [IL-23] cytokine, derived predominantly from macrophages and dendritic cells in response to microbial stimulation, has emerged as a critical promoter of chronic intestinal inflammation. Genome-wide association studies linking variants in IL23R to disease protection, bolstered by experimental evidence from colitis models, and the successful application of therapies against the IL-12/IL-23 shared p40 subunit in the treatment of inflammatory bowel disease [IBD] all provide compelling evidence of a crucial role for IL-23 in disease pathogenesis. Moreover, targeting the p19 subunit specific for IL-23 has shown considerable promise in recent phase 2 studies in IBD. The relative importance of the diverse immunological pathways downstream of IL-23 in propagating mucosal inflammation in the gut, however, remains contentious. Here we review current understanding of IL-23 biology and explore its pleiotropic effects on T cells, and innate lymphoid, myeloid and intestinal epithelial cells in the context of the pathogenesis of IBD. We furthermore discuss these pathways in the light of recent evidence from clinical trials and indicate emerging targets amenable to therapeutic intervention and translation into clinical practice.

Autophagy impairment in liver CD11c+ cells promotes non-alcoholic fatty liver disease through production of IL-23

There has been a global increase in rates of obesity with a parallel epidemic of non-alcoholic fatty liver disease (NAFLD). Autophagy is an essential mechanism involved in the degradation of cellular material and has an important function in the maintenance of liver homeostasis. Here, we explore the effect of Autophagy-related 5 (Atg5) deficiency in liver CD11c⁺ cells in mice fed HFD. When compared to control mice, Atg5-deficient CD11c⁺ mice exhibit increased glucose intolerance and decreased insulin sensitivity when fed HFD. This phenotype is associated with the development of NAFLD. We observe that IL-23 secretion is induced in hepatic CD11c⁺ myeloid cells following HFD feeding. We demonstrate that both therapeutic and preventative IL-23 blockade alleviates glucose intolerance, insulin resistance and protects against NAFLD development. This study provides insights into the function of autophagy and IL-23 production by hepatic CD11c⁺ cells in NAFLD pathogenesis and suggests potential therapeutic targets.

The function of autophagy and how this affects non-alcoholic fatty liver disease is not fully known. Here the authors show that in mice with a targeted disruption of the autophagy pathway in CD11c⁺ cells, development of NAFLD is accelerated involving IL-23 and blocking of IL-23 reduces disease.

Cross Talk between Gut Microbiota and Intestinal Mucosal Immunity in the Development of Ulcerative Colitis

Ulcerative colitis (UC), a nonspecific inflammatory disease, is characterized by inflammation and mucosal damage in the colon, and its prevalence in the world is increasing. Nevertheless, the exact pathogenesis of UC is still unclear. Accumulating data have suggested that its pathogenesis is multifactorial, involving genetic predisposition, environmental factors, microbial dysbiosis, and dysregulated immune responses. Generally, UC is aroused by inappropriate immune activation based on the interaction of host and intestinal microbiota. The relationship between microbiota and host immune system in the pathogenesis of UC is complicated. However, increasing evidence indicates that the shift of microbiota composition can substantially influence intestinal immunity. In this review, we primarily focus on the delicate balance between microbiota and gut mucosal immunity during UC progression.

An Insight into the Roles of Dietary Tryptophan and Its Metabolites in Intestinal Inflammation and Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is complex, chronic, and relapsing gastrointestinal inflammatory disorders, which includes mainly two conditions, namely ulcerative colitis (UC) and Crohn's disease (CD). Development of IBD in any individual is closely related to his/her autoimmune regulation, gene-microbiota interactions, and dietary factors. Dietary tryptophan (Trp) is an essential amino acid for intestinal mucosal cells, and it is associated with the intestinal inflammation, epithelial barrier, and energy homeostasis of the host. According to recent studies, Trp and its three major metabolic pathways, namely kynurenine (KYN) pathway, indole pathway, and 5-hydroxytryptamine (5-HT) pathway, have vital roles in the regulation of intestinal inflammation by acting directly or indirectly on the pro/anti-inflammatory cytokines, functions of various immune cells, as well as the intestinal microbial composition and homeostasis. In this review, recent advances in Trp- and its metabolites-associated intestinal inflammation are summarized. It further discusses the complex mechanisms and interrelationships of the three major metabolic pathways of Trp in regulating inflammation, which could elucidate the value of dietary Trp to be used as a nutrient for IBD patients.