Enterocolitis and colon cancer in interleukin-10-deficient mice are associated with aberrant cytokine production and CD4(+) TH1-like responses

Schistosoma mansoni soluble egg antigen suppresses colorectal cancer growth in vitro and in vivo

BACKGROUND

Colorectal cancer (CRC) is the third most common malignant disease around the world. Because the hosts' immunity plays a great part in regulating tumor cells' growth and progression, immunotherapies have therefore aroused great interest in treating cancers. Currently, scientists have investigated the use of Schistosoma-derived soluble egg antigens (SEA), which is known as a strong immune modulator, in treating a series of immune-related diseases.

METHODS

In this study, we investigated the anti-tumor effect of SEA against CRC using in vitro cell lines, HCT-116 and DLD-1, as well as in vivo mouse xenograft model. Approaches such as migration assay, invasion assay, and western blotting were done to analyze the anti-tumor effect of SEA. Furthermore, qRT-PCR and ELISA were performed to identify the immune profile of SEA-treated cells as well as SEA-treated xenograft mice.

RESULTS

In vitro studies suggested that SEA can dose-dependently inhibit the growth and progression of HCT-116 and DLD-1 cells. This inhibition was accompanied by a reduction of epithelial-mesenchymal transition (EMT), inflammasome inactivation, and apoptosis. SEA also downregulated the expression of IL-4 and IL-10 in the CRC cells, which may be the reason why their growth and progression were suppressed. In vivo studies showed a similar beneficial effect of SEA, as local administration of 25 μg SEA significantly inhibits tumor cell growth. SEA treatment also shifts the host's immunity from a pro-tumorigenic response to an anti-tumor response.

CONCLUSION

In conclusion, SEA may provide a beneficial effect against CRC, and further investigation may give promise in CRC treatment.

Colorectal Cancer-Derived Exosomes Impair CD4+ T Cell Function and Accelerate Cancer Progression via Macrophage Activation

Background: Exosomal programmed death ligand 1 (PD-L1), an exosomal membrane protein found in many tumor types, is consider to aid in regulation of the immune microenvironment. However, the functions and the mechanisms underlying the exosome-mediated regulation of the immune microenvironment in colorectal cancer (CRC) remain unknown. Methods: Western blotting was used to investigate the levels of exosomal PD-L1 in the peripheral blood of patients with CRC and healthy controls. A CRC mouse model was constructed by administering 10 mg/kg azoxymethane (AOM) and dextrane sodium sulfate (DSS) intraperitoneally. The mice were then administered the control or CRC-derived exosomes to examine the regulatory effect of the exosomes on macrophage infiltration and CRC development. In vitro studies, using a coculture system, and flow cytometry analysis were conducted to examine the relationship between the regulatory effect of CRC-derived exosomes on CD4+ T cells and tumor-associated macrophages. RNA-seq and reverse transcription-quantitative polymerase chain reaction assays were used to investigate the mechanisms underlying the regulatory effect of the CRC-derived exosomes on macrophage proliferation and the regulation of the immune microenvironment during CRC development. Results: In patients with CRC, higher levels of exosomal PD-L1 were associated with a more severe form of disease. The treatment of mice with AOM/DSS-induced CRC with CRC-derived exosomes resulted in high levels of macrophage proliferation, increased PD-L1 levels in macrophages, and accelerated CRC progression. Importantly, analysis of an in vitro coculture system and flow cytometry analysis showed that the CRC-derived exosomes transported PD-L1 into macrophages and impaired CD4+ T cell function. Preliminary data suggest that the NF-κb signaling pathway regulates the function of CRC-derived exosomal PD-L1-dependent macrophages. Conclusion: CRC-derived exosomes induce the proliferation of macrophages and increase their PD-L1 levels. They also impair CD4+ T cell function and promote CRC progression. Our findings reveal a novel exosomal PD-L1-mediated crosstalk between the CRC cells and immune cells in the CRC microenvironment.

IFN-γ-Induced intestinal epithelial cell-type-specific programmed cell death: PANoptosis and its modulation in Crohn's disease

Background

Crohn's disease (CD) is a chronic inflammatory bowel disease (IBD) and is considered a Th1-mediated disease, supported by the over-expression of interferon-gamma (IFN-γ) in the intestinal lamina propria. IFN-γ has a pleiotropic effect on the intestinal epithelial cells (IECs), suggesting that IFN-γ-induced responses may differ between epithelial cell types.

Methods

We established human small intestinal organoids (enteroids) derived from non-IBD controls and CD patients. Using human enteroids, the major response of IECs induced by IFN-γ was evaluated, focusing on the IFN-γ-induced programmed cell death (PCD) pathway. Identified IFN-γ-induced responses were validated in surgically resected intestinal samples and publicly available single-cell RNA-sequencing datasets.

Results

IFN-γ stimulated programmed cell death (PCD) of IECs in both control and CD enteroids in a dose-dependent manner. Pyroptosis, apoptosis. and necroptosis were activated in enteroids, suggesting that PANoptosis was the main process of IFN-γ-induced PCD in IECs. The response to IFN-γ depends on the cell type of the IECs. IFN-γ induced depletion of enterocytes with upregulation of PANoptosis-associated genes, while leading to expansion of goblet cells without significant change in PANoptosis-associated gene expression. Individual PCD inhibitors were insufficient to block IFN-γ-induced cytotoxicity, whereas the selective JAK1 inhibitor (upadacitinib) effectively blocked IFN-γ-induced cytotoxicity and PANoptosis. Furthermore, PANoptosis was significantly activated in surgically resected tissues and in publicly available single-cell RNA-sequencing datasets of intestinal tissues from patients with CD.

Conclusion

IFN-γ induces PANoptosis in enterocytes, which can be treated with a selective JAK1 inhibitor in patients with CD.

IL-10-Directed Cancer Immunotherapy: Preclinical Advances, Clinical Insights, and Future Perspectives

Interleukin-10 (IL-10) is a dimeric cytokine encoded by the IL-10 gene on chromosome 1 [...].

Crohn's Disease-associated variant in laccase domain containing 1 (LACC1) modulates T cell gene expression, metabolism and T cell function

Genome wide association studies (GWAS) identify many risks for Crohn's disease (CD), including a site near the metabolism gene laccase domain containing 1 (LACC1). We previously found this site near LACC1 was associated with decreased LACC1 expression in T lymphocytes, yet the mechanism affecting gene expression and its links to T cell function and inflammatory disease were unknown. Here we identify variants in the promoter region that influence transcription of LACC1. Direct association of disease-risk variants with lower LACC1 pre-mRNA in human CD4+ T cells is confirmed by comparing transcripts from each allele from donors heterozygous for the LACC1 CD-risk allele. Using gene editing, we validate the function of this promoter region in LACC1 expression in T cells. Human CD4+ T cells with LACC1 gene knockdown show altered metabolism, including reduced oxygen consumption rate, and reduced in vitro regulatory T cell differentiation. Therefore, our study provides a mechanism linking these specific LACC1 variants to colitis by attributing promoter region variants to changes in T cell metabolism and function.

Fecal microbiota transplantation mitigates cardiac remodeling and functional impairment in mice with chronic colitis

Background

Inflammatory bowel disease (IBD) is a chronic inflammatory disorder with significant extraintestinal manifestations, including cardiovascular derangements. However, the molecular mechanisms underlying the cardiac remodeling and dysfunction remain unclear.

Methods

We investigated the effects of chronic colitis on the heart using two mouse models: DSS-induced colitis and Il10 -/- spontaneous colitis. Echocardiography was employed to assess heart function and molecular characterization was performed using bulk RNA-sequencing, RT-qPCR, and western blot.

Results

Both models exhibited significant cardiac impairment, including reduced ejection fraction and fractional shortening as well as increased collagen deposition, inflammation, and myofibril reorganization. Molecular analyses revealed upregulation of fibrosis markers (i.e. COL1A1, COL3A1, Fibronectin) and β-catenin reactivation, indicating a pro-fibrotic cardiac environment. Each model yielded common upregulation of eicosanoid-associated and inflammatory genes ( Cyp2e1 , Map3k6 , Pck1 , Cfd ), and model-specific alterations in pathways regulating cAMP- and cGMP-signaling, arachidonic and linoleic acid metabolism, Cushing syndrome-related genes, and immune cell responses. DSS colitis caused differential regulation of 232 cardiac genes, while Il10 -/- colitis yielded 105 dysregulated genes, revealing distinct molecular pathways driving cardiac dysfunction. Importantly, therapeutic fecal microbiota transplantation (FMT) restored heart function in both models, characterized by reduced fibrosis markers and downregulated pro-inflammatory genes ( Lbp and Cdkn1a in Il10 -/- mice and Fos in DSS mice), while also mitigating intestinal inflammation. Post-FMT cardiac RNA-sequencing revealed significant gene expression changes, with three altered genes in DSS mice and 67 genes in Il10 -/- mice. Notably, Il10 -/- mice showed relatively less cardiac recovery following FMT, highlighting IL-10's cardioprotective and anti-inflammatory contribution.

Conclusions

Our findings elucidate novel insights into colitis-induced cardiac remodeling and dysfunction and suggest that FMT mitigates cardiac dysfunction by attenuating systemic inflammation and correcting gut dysbiosis. This study underscores the need for further evaluation of gut-heart interactions and microbiome-based therapies to improve cardiovascular health in IBD patients.

Early subclinical stages of the inflammatory bowel diseases: insights from human and animal studies

The inflammatory bowel diseases (IBD) occur in genetically susceptible individuals that mount inappropriate immune responses to their microbiota leading to chronic intestinal inflammation. The natural history of IBD progression begins with early subclinical stages of disease that occur before clinical diagnosis. Improved understanding of those early subclinical stages could lead to new or improved strategies for IBD diagnosis, prognostication, or prevention. Here, we review our current understanding of the early subclinical stages of IBD in humans including studies from first-degree relatives of patients with IBD and members of the general population who go on to develop IBD. We also discuss representative mouse models of IBD that can be used to investigate disease dynamics and host-microbiota relationships during these early stages. In particular, we underscore how mouse models of IBD that develop disease later in life with variable penetrance may present valuable opportunities to discern early subclinical mechanisms of disease before histological inflammation and other severe symptoms become apparent.

STARD7 maintains intestinal epithelial mitochondria architecture, barrier integrity, and protection from colitis

Susceptibility to inflammatory bowel diseases (IBDs), Crohn's disease (CD), and ulcerative colitis (UC) is linked with loss of intestinal epithelial barrier integrity and mitochondria dysfunction. Steroidogenic acute regulatory (StAR) protein-related lipid transfer (START) domain-containing protein 7 (STARD7) is a phosphatidylcholine-specific (PC-specific) lipid transfer protein that transports PC from the ER to the mitochondria, facilitating mitochondria membrane stabilization and respiration function. The aim of this study was to define the contribution of STARD7 in the regulation of the intestinal epithelial mitochondrial function and susceptibility to colitis. In silico analyses identified significantly reduced expression of STARD7 in patients with UC, which was associated with downregulation of metabolic function and a more severe disease phenotype. STARD7 was expressed in intestinal epithelial cells, and STARD7 knockdown resulted in deformed mitochondria and diminished aerobic respiration. Loss of mitochondria function was associated with reduced expression of tight junction proteins and loss of intestinal epithelial barrier integrity that could be recovered by AMPK activation. Stard7+/- mice were more susceptible to the development of DSS-induced and Il10-/- spontaneous models of colitis. STARD7 is critical for intestinal epithelial mitochondrial function and barrier integrity, and loss of STARD7 function increases susceptibility to IBD.

IL-10 promotes Th17 cell differentiation by enhancing STAT1-dependent IL-6 production via IgE-stimulated mast cells

Mast cells (MCs) are tissue-resident cells of hematopoietic origin that play an important role in host's defense mechanism against nematodes. However, excessive activation of these cells contributes to the development of certain allergic diseases. Immunoglobin E (IgE) is one of the well-known molecules that activate MCs. Even in the absence of specific antigens, the binding of highly cytokinergic IgE to FcεRI on MCs prolongs their survival and induces cytokine production without enhancing their degranulation. In the present study, we examined the effects of the members of the interleukin-10 (IL-10) family of cytokines on IgE-mediated MCs functions. The receptors including Il10r1, Il10r2, and Il20r2, but not Il20r1, Il22r1 or Il28r1, were constitutively expressed in mouse bone marrow cell-derived cultured MCs (BMCMCs), suggesting that IL-10 may influence MCs function. Indeed, we found that only IL-10 could influence upon BMCMCs function; IL-10 enhanced prolongation of survival, promoted IL-6 and/or IL-13 production dependently of STAT1 and STAT3, and suppressed tumor necrosis factor production independently of STAT1 and STAT3 on IgE-stimulated BMCMCs. Moreover, the IL-10-mediated enhancement of IL-6 production by IgE-stimulated BMCMCs promotes Th17 cell expansion. These results suggest that IL-10 has a dual role as an anti-inflammatory and pro-inflammatory cytokine in MCs functions.

DJ-X-013 reduces LPS-induced inflammation, modulates Th17/ myeloid-derived suppressor cells, and alters NF-κB expression to ameliorate experimental colitis

SCOPE

Inflammatory bowel disease (IBD) is a chronic intestinal inflammatory condition of unknown etiology, although recent evidence suggests that it is caused by an excessive immune response to mucosal antigens. We determined the anti-inflammatory properties of novel compound DJ-X-013 in vitro in lipopolysaccharide (LPS)-induced macrophages and in an in vivo dextran sodium sulfate (DSS)-induced model of colitis.

METHODS AND RESULTS

To evaluate the anti-inflammatory properties of DJ-X-013, we used LPS-activated RAW 264.7 macrophages in vitro and a DSS-induced experimental model of colitis in vivo. We examine cellular morphology, and tissue architecture by histology, flow cytometry, RT-qPCR, multiplex, and immunoblot analysis to perform cellular and molecular studies. DJ-X-013 treatment altered cell morphology and expression of inflammatory cytokines in LPS-activated macrophages as compared to cells treated with LPS alone. DJ-X-013 also impeded the migration of RAW 264.7 macrophages by modulating cytoskeletal organization and suppressed the expression of NF-κB and inflammatory markers as compared to LPS alone. DJ-X-013 treatment improved body weight, and colon length and attenuated inflammation in the colon of DSS-induced colitis. Intriguingly, DSS-challenged mice treated with DJ-X-013 induced the numbers of myeloid-derived suppressor cells (MDSCs), dendritic cells (DCs), and natural killer T cells (NKT) in the colon lamina propria (LP) relative to DSS. DJ-X-013 also reduced the influx of neutrophils, TNF-α producing macrophages, restricted the number of Th17 cells, and suppressed inflammatory cytokines and NF-κB in the LP relative to DSS.

CONCLUSION

DJ-X-013 is proposed to be a therapeutic strategy for ameliorating inflammation and experimental colitis.

Stimulating the Antitumor Immune Response Using Immunocytokines: A Preclinical and Clinical Overview

Cytokines are immune modulators which can enhance the immune response and have been proven to be an effective class of immunotherapy. Nevertheless, the clinical use of cytokines in cancer treatment has faced several challenges associated with poor pharmacokinetic properties and the occurrence of adverse effects. Immunocytokines (ICKs) have emerged as a promising approach to overcome the pharmacological limitations observed with cytokines. ICKs are fusion proteins designed to deliver cytokines in the tumor microenvironment by taking advantage of the stability and specificity of immunoglobulin-based scaffolds. Several technological approaches have been developed. This review focuses on ICKs designed with the most impactful cytokines in the cancer field: IL-2, TNFα, IL-10, IL-12, IL-15, IL-21, IFNγ, GM-CSF, and IFNα. An overview of the pharmacological effects of the naked cytokines and ICKs tested for cancer therapy is detailed. A particular emphasis is given on the immunomodulatory effects of ICKs associated with their technological design. In conclusion, this review highlights active ways of development of ICKs. Their already promising results observed in clinical trials are likely to be improved with the advances in targeting technologies such as cytokine/linker engineering and the design of multispecific antibodies with tumor targeting and immunostimulatory functional properties.

Interleukin-17 directly stimulates tumor infiltrating Tregs to prevent cancer development

Background

Interleukin-17 (IL-17) family cytokines promote protective inflammation for pathogen resistance, but also facilitate autoimmunity and tumor development. A direct signal of IL-17 to regulatory T cells (Tregs) has not been reported and may help explain these dichotomous responses.

Methods

We generated a conditional knockout of Il17ra in Tregs by crossing Foxp3-YFP-Cre mice to Il17ra-flox mice (Il17ra ΔTreg mice). Subsequently, we adoptively transferred bone marrow cells from Il17ra ΔTreg mice to a mouse model of sporadic colorectal cancer (Cdx2-Cre +/Apc F/+), to selectively ablate IL-17 direct signaling on Tregs in colorectal cancer. Single cell RNA sequencing and bulk RNA sequencing were performed on purified Tregs from mouse colorectal tumors, and compared to those of human tumor infiltrating Treg cells.

Results

IL-17 Receptor A (IL-17RA) is expressed in Tregs that reside in mouse mesenteric lymph nodes and colon tumors. Ablation of IL-17RA, specifically in Tregs, resulted in increased Th17 cells, and exacerbated tumor development. Mechanistically, tumor-infiltrating Tregs exhibit a unique gene signature that is linked to their activation, maturation, and suppression function, and this signature is in part supported by the direct signaling of IL-17 to Tregs. To study pathways of Treg programming, we found that loss of IL-17RA in tumor Tregs resulted in reduced RNA splicing, and downregulation of several RNA binding proteins that are known to regulate alternative splicing and promote Treg function.

Conclusion

IL-17 directly signals to Tregs and promotes their maturation and function. This signaling pathway constitutes a negative feedback loop that controls cancer-promoting inflammation in CRC.

Myeloid Cells and Sphingosine-1-Phosphate Are Required for TCRαβ Intraepithelial Lymphocyte Recruitment to the Colon Epithelium

Intraepithelial lymphocytes (IELs) are T cells important for the maintenance of barrier integrity in the intestine. Colon IELs are significantly reduced in both MyD88-deficient mice and those lacking an intact microbiota, suggesting that MyD88-mediated detection of bacterial products is important for the recruitment and/or retention of these cells. Here, using conditionally deficient MyD88 mice, we show that myeloid cells are the key mediators of TCRαβ+ IEL recruitment to the colon. Upon exposure to luminal bacteria, myeloid cells produce sphingosine-1-phosphate (S1P) in a MyD88-dependent fashion. TCRαβ+ IEL recruitment may be blocked using the S1P receptor antagonist FTY720, confirming the importance of S1P in the recruitment of TCRαβ+ IELs to the colon epithelium. Finally, using the TNFΔARE/+ model of Crohn's-like bowel inflammation, we show that disruption of colon IEL recruitment through myeloid-specific MyD88 deficiency results in reduced pathology. Our results illustrate one mechanism for recruitment of a subset of IELs to the colon.

HIF-1α facilitates glioma proliferation and invasion by activating pyroptosis signaling axis

BACKGROUND

HIF-1α is thought to be a novel regulator which contributes to carcinogenesis. However, the mechanism underlying the effect of HIF-1α in gliomas remains largely unknown.

METHODS

In the research, we demonstrate that HIF-lα mRNA and protein levels are elevated in glioma cells. The colony formation assays, transwell assays, and wound-healing assays showed that overexpression of HIF-1α promoted proliferation and invasion of glioma cells.

RESULTS

Overexpression of HIF-lα also increased the expression of inflammatory factors related to pyrolysis (TNF-α, IL-10, and IL-1β) and protein related to pyrolysis signal pathway (NLRP3, ASC, caspase-1, GSDMD, and GSDME).

CONCLUSIONS

Therefore, we speculate that HIF-1α promotes the proliferation and invasion of glial cells by regulating pyrolysis pathway. These results might provide a novel strategy and target for treatment of glioma.

From periphery to center stage: 50 years of advancements in innate immunity

Over the past 50 years in the field of immunology, something of a Copernican revolution has happened. For a long time, immunologists were mainly concerned with what is termed adaptive immunity, which involves the exquisitely specific activities of lymphocytes. But the other arm of immunity, so-called "innate immunity," had been neglected. To celebrate Cell's 50th anniversary, we have put together a review of the processes and components of innate immunity and trace the seminal contributions leading to the modern state of this field. Innate immunity has joined adaptive immunity in the center of interest for all those who study the body's defenses, as well as homeostasis and pathology. We are now entering the era where therapeutic targeting of innate immune receptors and downstream signals hold substantial promise for infectious and inflammatory diseases and cancer.

Fibrosis in IBD: from pathogenesis to therapeutic targets

BACKGROUND

Intestinal fibrosis resulting in stricture formation and obstruction in Crohn's disease (CD) and increased wall stiffness leading to symptoms in ulcerative colitis (UC) is among the largest unmet needs in inflammatory bowel disease (IBD). Fibrosis is caused by a multifactorial and complex process involving immune and non-immune cells, their soluble mediators and exposure to luminal contents, such as microbiota and environmental factors. To date, no antifibrotic therapy is available. Some progress has been made in creating consensus definitions and measurements to quantify stricture morphology for clinical practice and trials, but approaches to determine the degree of fibrosis within a stricture are still lacking.

OBJECTIVE

We herein describe the current state of stricture pathogenesis, measuring tools and clinical trial endpoints development.

DESIGN

Data presented and discussed in this review derive from the past and recent literature and the authors' own research and experience.

RESULTS AND CONCLUSIONS

Significant progress has been made in better understanding the pathogenesis of fibrosis, but additional studies and preclinical developments are needed to define specific therapeutic targets.

The complex role of IL-10 in malignant ascites: a review

The emergence of malignant ascites (MA) indicates poor prognoses in patients with ovarian, gastrointestinal, breast, and pancreatic cancer. Interleukin-10 (IL-10) is a pleiotropic cytokine with immunoregulatory effects in tumor microenvironment. The level of IL-10 in MA varied across cancer types and patients, influencing cancer progression and outcomes. Originating from various immune and cancer cells, IL-10 contributes to complex signaling pathways in MA. Systemic IL-10 administration, although the evidence of its efficacy on MA is limited, still emerges as a promising therapeutic strategy because it can increase CD8+ T cells cytotoxicity and invigorate exhausted CD8+ tumor infiltration lymphocytes (TILs) directly. IL-10 signaling blockade also demonstrates great potential when combined with other immunotherapies in MA treatment. We reviewed the levels, origins, and functions of IL-10 in malignant ascites and overviewed the current IL-10 signaling targeting therapies, aiming to provide insights for MA treatment.

Reduced estrogen signaling contributes to bone loss and cardiac dysfunction in interleukin-10 knockout mice

Characterization of the interleukin (IL)-10 knockout (KO) mouse with chronic gut inflammation, cardiovascular dysfunction, and bone loss suggests a critical role for this cytokine in interorgan communication within the gut, bone, and cardiovascular axis. We sought to understand the role of IL-10 in the cross-talk between these systems. Six-week-old IL-10 KO mice and their wild type (WT) counterparts were maintained on a standard rodent diet for 3 or 6 months. Gene expression of proinflammatory markers and Fgf23, serum 17β-estradiol (E2), and cardiac protein expression were assessed. Ileal Il17a and Tnf mRNA increased while Il6 mRNA increased in the bone and heart by at least 2-fold in IL-10 KO mice. Bone Dmp1 and Phex mRNA were repressed at 6 months in IL-10 KO mice, resulting in increased Fgf23 mRNA (~4-fold) that contributed to increased fibrosis. In the IL-10 KO mice, gut bacterial β-glucuronidase activity and ovarian Cyp19a1 mRNA were lower (p < 0.05), consistent with reduced serum E2 and reduced cardiac pNOS3 (Ser1119 ) in these mice. Treatment of ileal lymphocytes with E2 reduced gut inflammation in WT but not IL-10 KO mice. In conclusion, our data suggest that diminished estrogen and defective bone mineralization increased FGF23 which contributed to cardiac fibrosis in the IL-10 KO mouse.

DSS treatment does not affect murine colonic microbiota in absence of the host

The prevalence of inflammatory bowel disease (IBD) is rising globally; however, its etiology is still not fully understood. Patient genetics, immune system, and intestinal microbiota are considered critical factors contributing to IBD. Preclinical animal models are crucial to better understand the importance of individual contributing factors. Among these, the dextran sodium sulfate (DSS) colitis model is the most widely used. DSS treatment induces gut inflammation and dysbiosis. However, its exact mode of action remains unclear. To determine whether DSS treatment induces pathogenic changes in the microbiota, we investigated the microbiota-modulating effects of DSS on murine microbiota in vitro. For this purpose, we cultured murine microbiota from the colon in six replicate continuous bioreactors. Three bioreactors were supplemented with 1% DSS and compared with the remaining PBS-treated control bioreactors by means of microbiota taxonomy and functionality. Using metaproteomics, we did not identify significant changes in microbial taxonomy, either at the phylum or genus levels. No differences in the metabolic pathways were observed. Furthermore, the global metabolome and targeted short-chain fatty acid (SCFA) quantification did not reveal any DSS-related changes. DSS had negligible effects on microbial functionality and taxonomy in vitro in the absence of the host environment. Our results underline that the DSS colitis mouse model is a suitable model to study host-microbiota interactions, which may help to understand how intestinal inflammation modulates the microbiota at the taxonomic and functional levels.

Single cell RNA-sequencing profiling to improve the translation between human IBD and in vivo models

Inflammatory bowel disease (IBD) is an umbrella term for two conditions (Crohn's Disease and Ulcerative Colitis) that is characterized by chronic inflammation of the gastrointestinal tract. The use of pre-clinical animal models has been invaluable for the understanding of potential disease mechanisms. However, despite promising results of numerous therapeutics in mouse colitis models, many of these therapies did not show clinical benefits in patients with IBD. Single cell RNA-sequencing (scRNA-seq) has recently revolutionized our understanding of complex interactions between the immune system, stromal cells, and epithelial cells by mapping novel cell subpopulations and their remodeling during disease. This technology has not been widely applied to pre-clinical models of IBD. ScRNA-seq profiling of murine models may provide an opportunity to increase the translatability into the clinic, and to choose the most appropriate model to test hypotheses and novel therapeutics. In this review, we have summarized some of the key findings at the single cell transcriptomic level in IBD, how specific signatures have been functionally validated in vivo, and highlighted the similarities and differences between scRNA-seq findings in human IBD and experimental mouse models. In each section of this review, we highlight the importance of utilizing this technology to find the most suitable or translational models of IBD based on the cellular therapeutic target.

Gut immune microenvironment and autoimmunity

A variety of immune cells or tissues are present in the gut to form the gut immune microenvironment by interacting with gut microbiota, and to maintain the gut immune homeostasis. Accumulating evidence indicated that gut microbiota dysbiosis might break the homeostasis of the gut immune microenvironment, which was associated with many health problems including autoimmune diseases. Moreover, disturbance of the gut immune microenvironment can also induce extra-intestinal autoimmune disorders through the migration of intestinal pro-inflammatory effector cells from the intestine to peripheral inflamed sites. This review discussed the composition of the gut immune microenvironment and its association with autoimmunity. These findings are expected to provide new insights into the pathogenesis of various autoimmune disorders, as well as novel strategies for the prevention and treatment against related diseases.

CPW partially attenuates DSS-induced ulcerative colitis in mice

Ulcerative colitis (UC) is a chronic inflammatory bowel disease (IBD) of the gastrointestinal tract. The etiology is not fully understood, but environmental, microbial, and immunologic factors, as well as a genetic predisposition, play a role. UC is characterized by episodes of abdominal pain, diarrhea, bloody stools, weight loss, severe colonic inflammation, and ulceration. Despite the increase in the frequency of UC and the deterioration of the quality of life, there are still patients who do not respond well to available treatment options. Against this background, natural products such as polysaccharides are becoming increasingly important as they protect the intestinal mucosa, promote wound healing, relieve inflammation and pain, and restore intestinal motility. In this study, we investigated the effect of a polysaccharide isolated from the biomass of Campomanesia adamantium and Campomanesia pubescens (here referred to as CPW) in an experimental model of acute and chronic ulcerative colitis induced by dextran sulfate sodium (DSS). CPW reversed weight loss, increased disease activity index (DAI), bloody diarrhea, and colon shortening. In addition, CPW reduced visceral mechanical hypersensitivity, controlled oxidative stress and inflammation, and protected the mucosal barrier. CPW is not absorbed in the intestine, does not inhibit cytochrome P450 proteins, and does not exhibit AMES toxicity. These results suggest that CPW attenuates DSS-induced acute and chronic colitis in mice and may be a potential alternative treatment for UC.

Targeting IL-23 for the interception of obesity-associated colorectal cancer

Inflammation and obesity are two major factors that promote Colorectal cancer (CRC). Our recent data suggests that interleukin (IL)-23, is significantly elevated in CRC tumors and correlates with patient obesity, tumor grade and survival. Thus, we hypothesize that obesity and CRC may be linked via inflammation and IL-23 may be a potential target for intervention in high-risk patients. TCGA dataset and patient sera were evaluated for IL-23A levels. IL-23A [IL-23 p19-/-] knockout (KO) mice were crossed to Apcmin/+ mice and progeny were fed low-fat or high-fat diets. At termination intestines were evaluated for tumorigenesis. Tumors, serum, and fecal contents were analyzed for protein biomarkers, cytokines, and microbiome profile respectively. IL-23A levels are elevated in the sera of patients with obesity and colon tumors. Genetic ablation of IL-23A significantly suppressed colonic tumor multiplicity (76-96 %) and incidence (72-95 %) in male and female mice. Similarly, small-intestinal tumor multiplicity and size were also significantly reduced in IL-23A KO mice. IL-23A knockdown in Apcmin/+ mice fed high-fat diet, also resulted in significant suppression of colonic (50-58 %) and SI (41-48 %) tumor multiplicity. Cytokine profiling showed reduction in several circulating pro-inflammatory cytokines including loss of IL-23A. Biomarker analysis suggested reduced tumor cell proliferation and immune modulation with an increase in tumor-infiltrating CD4+ and CD8+ T-lymphocytes in the IL-23A KO mice compared to controls. Fecal microbiome analysis revealed potentially beneficial changes in the bacterial population profile. In summary, our data indicates a tumor promoting role for IL-23 in CRC including diet-induced obesity. With several IL-23 targeted therapies in clinical trials, there is a great potential for targeting this cytokine for CRC prevention and therapy.

M2a macrophages facilitate resolution of chemically-induced colitis in TLR4-SNP mice

IMPORTANCE

Inflammatory bowel disease (IBD), including Crohn's disease and ulcerative colitis, impacts millions of individuals worldwide and severely impairs the quality of life for patients. Dysregulation of innate immune signaling pathways reduces barrier function and exacerbates disease progression. Macrophage (Mφ) signaling pathways are potential targets for IBD therapies. While multiple treatments are available for IBD, (i) not all patients respond, (ii) responses may diminish over time, and (iii) treatments often have undesirable side effects. Genetic studies have shown that the inheritance of two co-segregating SNPs expressed in the innate immune receptor, TLR4, is associated with human IBD. Mice expressing homologous SNPs ("TLR4-SNP" mice) exhibited more severe colitis than WT mice in a DSS-induced colonic inflammation/repair model. We identified a critical role for M2a "tissue repair" Mφ in the resolution of colitis. Our findings provide insight into potential development of novel therapies targeting Mφ signaling pathways that aim to alleviate the debilitating symptoms experienced by individuals with IBD.

Epithelial NAD+ depletion drives mitochondrial dysfunction and contributes to intestinal inflammation

Introduction

We have previously demonstrated that a pathologic downregulation of peroxisome proliferator-activated receptor-gamma coactivator 1-alpha (PGC1α) within the intestinal epithelium contributes to the pathogenesis of inflammatory bowel disease (IBD). However, the mechanism underlying downregulation of PGC1α expression and activity during IBD is not yet clear.

Methods

Mice (male; C57Bl/6, Villincre/+;Pgc1afl/fl mice, and Pgc1afl/fl) were subjected to experimental colitis and treated with nicotinamide riboside. Western blot, high-resolution respirometry, nicotinamide adenine dinucleotide (NAD+) quantification, and immunoprecipitation were used to in this study.

Results

We demonstrate a significant depletion in the NAD+ levels within the intestinal epithelium of mice undergoing experimental colitis, as well as humans with ulcerative colitis. While we found no decrease in the levels of NAD+-synthesizing enzymes within the intestinal epithelium of mice undergoing experimental colitis, we did find an increase in the mRNA level, as well as the enzymatic activity, of the NAD+-consuming enzyme poly(ADP-ribose) polymerase-1 (PARP1). Treatment of mice undergoing experimental colitis with an NAD+ precursor reduced the severity of colitis, restored mitochondrial function, and increased active PGC1α levels; however, NAD+ repletion did not benefit transgenic mice that lack PGC1α within the intestinal epithelium, suggesting that the therapeutic effects require an intact PGC1α axis.

Discussion

Our results emphasize the importance of PGC1α expression to both mitochondrial health and homeostasis within the intestinal epithelium and suggest a novel therapeutic approach for disease management. These findings also provide a mechanistic basis for clinical trials of nicotinamide riboside in IBD patients.

Interleukin-10 in cancer immunotherapy: from bench to bedside

Interleukin (IL)-10 was one of the first cytokines to be recognized. However, its functionality in promoting antitumor immunity was described more recently. Context- and concentration-dependent biological effects are the hallmarks of the pleiotropic role of IL-10. Despite reducing tumor-promoting inflammation, IL-10 may have a role in rejuvenating exhausted tumor-resident T cells. Contrary to the assumption that IL-10 produces an immunosuppressive tumor microenvironment (TME), it promotes activation of tumor-resident CD8+ T cells, which aids tumor rejection. Emerging data from published early-Phase trials have shown mixed results in different tumor types. In this review, we summarize the biological effects of IL-10 and highlight the clinical experience using pegilodecakin.

Petiveria alliacea Reduces Tumor Burden and Metastasis and Regulates the Peripheral Immune Response in a Murine Myeloid Leukemia Model

The poor response, adverse effects and drug resistance to treatment of acute myeloid leukemia (AML) have led to searching for safer and more effective therapeutic alternatives. We previously demonstrated that the alcoholic extract of Petiveria alliacea (Esperanza) has a significant in vitro antitumor effect on other tumor cells and also the ability to regulate energy metabolism. We evaluated the effect of the Esperanza extract in vitro and in vivo in a murine model of AML with DA-3/ER-GM cells. First, a chemical characterization of the extract was conducted through liquid and gas chromatography coupled with mass spectrometry. In vitro findings showed that the extract modulates tumor metabolism by decreasing glucose uptake and increasing reactive oxygen species, which leads to a reduction in cell proliferation. Then, to evaluate the effect of the extract in vivo, we standardized the mouse model by injecting DA-3/ER-GM cells intravenously. The animals treated with the extract showed a lower percentage of circulating blasts, higher values of hemoglobin, hematocrit, and platelets, less infiltration of blasts in the spleen, and greater production of cytokines compared to the control group. These results suggest that the antitumor activity of this extract on DA-3/ER-GM cells can be attributed to the decrease in glycolytic metabolism, its activity as a mitocan, and the possible immunomodulatory effect by reducing tumor proliferation and metastasis.

IL-17-driven induction of Paneth cell antimicrobial functions protects the host from microbiota dysbiosis and inflammation in the ileum

Interleukin (IL)-17 protects epithelial barriers by inducing the secretion of antimicrobial peptides. However, the effect of IL-17 on Paneth cells (PCs), the major producers of antimicrobial peptides in the small intestine, is unclear. Here, we show that the targeted ablation of the IL-17 receptor (IL-17R) in PCs disrupts their antimicrobial functions and decreases the frequency of ileal PCs. These changes become more pronounced after colonization with IL-17 inducing segmented filamentous bacteria. Mice with PCs that lack IL-17R show an increased inflammatory transcriptional profile in the ileum along with the severity of experimentally induced ileitis. These changes are associated with a decrease in the diversity of gut microbiota that induces a severe ileum pathology upon transfer to genetically susceptible mice, which can be prevented by the systemic administration of IL-17a/f in microbiota recipients. In an exploratory analysis of a small cohort of pediatric patients with Crohn's disease, we have found that a portion of these patients exhibits a low number of lysozyme-expressing ileal PCs and a high ileitis severity score, resembling the phenotype of mice with IL-17R-deficient PCs. Our study identifies IL-17R-dependent signaling in PCs as an important mechanism that maintains ileal homeostasis through the prevention of dysbiosis.

Regulatory T Cells Secrete IL10 to Suppress Neuroinflammation in Early Stage after Subarachnoid Hemorrhage

Objective: Accumulating evidence supports neuroprotective effects of regulatory T cells (Tregs) in response to brain injury. However, the precise mechanisms underlying the beneficial effects of Tregs on suppressing neuroinflammation after subarachnoid hemorrhage (SAH) remain unclear. Methods: We performed flow cytometry to detect the infiltration of Tregs into the brain at different time points after SAH. Behavioral tests, including Adhesive and Rotarod, were performed to assess neurological deficits in mice after SAH. Bulk RNA sequencing was used to investigate the transcriptomic change of Tregs infiltrating into the brain after SAH. qPCR was performed to verify the variation of inflammatory cytokines expression in the brain after Tregs exogenous infusion. FoxP3-DTR mice and Il10 gene KO mice were used to explore the mechanism of Tregs inhibiting neuron apoptosis after infiltrating the brain following SAH onset. Results: Peripheral Tregs infiltrated into the brain one day after SAH and gradually accumulated in the hemorrhagic hemisphere. An exogenous infusion of Tregs significantly improved the neurological function of mice after SAH, while poor recovery of neurological function was observed in Tregs depletion mice. Transcriptome sequencing data suggested that the immunosuppressive function of brain-infiltrated Tregs was significantly upregulated. qPCR showed that the expression of pro-inflammatory cytokines decreased in the brain of SAH mice after exogenous Tregs infusion. Bioinformatic analysis revealed that IL-10 and other cytokines secreted by brain-infiltrated Tregs were upregulated after SAH. Moreover, exogenous infusion of Il10 gene KO Tregs did not totally improve neurological function in SAH mice. Conclusions: Tregs infiltrated into the brain in the early stage after SAH and exerted neuroprotective effect by secreting IL-10 to suppress neuroinflammation and reduce neuron apoptosis.

Evaluation of the association of chronic inflammation and cancer: Insights and implications

Among the most extensively researched processes in the development and treatment of cancer is inflammatory condition. Although acute inflammation is essential for the wound healing and reconstruction of tissues that have been damaged, chronic inflammation may contribute to the onset and growth of a number of diseases, including cancer. By disrupting the signaling processes of cells, which result in cancer induction, invasion, and development, a variety of inflammatory molecules are linked to the development of cancer. The microenvironment surrounding the tumor is greatly influenced by inflammatory cells and their subsequent secretions, which also contribute significantly to the tumor's growth, survivability, and potential migration. These inflammatory variables have been mentioned in several publications as prospective diagnostic tools for anticipating the onset of cancer. Targeting inflammation with various therapies can reduce the inflammatory response and potentially limit or block the proliferation of cancer cells. The scientific medical literature from the past three decades has been studied to determine how inflammatory chemicals and cell signaling pathways related to cancer invasion and metastasis are related. The current narrative review updates the relevant literature while highlighting the specifics of inflammatory signaling pathways in cancer and their possible therapeutic possibilities.

Amelioration of Murine Colitis by Attenuated Salmonella choleraesuis Encoding Interleukin-19

The imbalance of mucosal immunity in the lower gastrointestinal tract can lead to chronic inflammatory bowel diseases (IBDs), including Crohn's disease and ulcerative colitis. IBD is a chronic inflammatory disorder that causes small and/or large intestines ulceration. According to previous studies, recombinant interleukin (IL)-10 protein and genetically modified bacteria secreting IL-10 ameliorate dextran sulfate sodium (DSS)-induced colitis in mice. IL-19 is a transcriptional activator of IL-10 and can alter the balance of T helper 1 (Th)1/Th2 cells in favor of Th2. In this study, we aimed to investigate whether the expression of the murine IL-19 gene carried by Salmonella choleraesuis (S. choleraesuis) could ameliorate murine IBD. Our results showed that the attenuated S. choleraesuis could carry and express the IL-19 gene-containing plasmid for IBD gene therapy by reducing the mortality and clinical signs in DSS-induced acute colitis mice as compared to the untreated ones. We also found that IL-10 expression was induced in IL-19-treated colitis mice and prevented inflammatory infiltrates and proinflammatory cytokine expression in these mice. We suggest that S. choleraesuis encoding IL-19 provides a new strategy for treating IBD in the future.

Risk of Cancer in Inflammatory Bowel Disease and Pitfalls in Oncologic Therapy

BACKGROUND

Inflammatory bowel disease (IBD), represented by ulcerative colitis and Crohn's disease, is an idiopathic condition caused by a dysregulated immune response to host intestinal microflora, leading to chronic relapsing intestinal inflammation. Individuals with IBD are more prone to die from several diseases, including cancer.

METHODS

An extensive search was conducted of PubMed using the following medical subject heading-"inflammatory bowel disease" OR "Crohn's disease" OR "ulcerative colitis" AND "cancer."

RESULTS

In this review article, we discuss the oncogenic mechanisms and genomics of colitis-associated colorectal cancer. Beyond this, we describe the multiple other malignancies that IBD patients are at risk for, discuss caveats in the screening and diagnosis of those cancers, and shed light on pitfalls on the management and treatment of cancer in IBD patients.

CONCLUSION

Patients, caregivers, and health professionals who deal with IBD must be educated on how to identify warning signs so that cancers can be diagnosed and treated as early as possible.

Intestinal Tr1 Cells Confer Protection against Colitis in the Absence of Foxp3+ Regulatory T Cell-Derived IL-10

The intestinal mucosa is continually exposed to diverse microbial and dietary Ags, requiring coordinated efforts by specialized populations of regulatory T cells (Tregs) to maintain homeostasis. Suppressive mechanisms used by intestinal Tregs include the secretion of anti-inflammatory cytokines such as IL-10 and TGF-β. Defects in IL-10 signaling are associated with severe infantile enterocolitis in humans, and mice deficient in IL-10 or its receptors develop spontaneous colitis. To determine the requirement of Foxp3+ Treg-specific IL-10 for protection against colitis, we generated Foxp3-specific IL-10 knockout (KO) mice (IL-10 conditional KO [cKO] mice). Colonic Foxp3+ Tregs isolated from IL-10cKO mice showed impaired ex vivo suppressive function, although IL-10cKO mice maintained normal body weights and developed only mild inflammation over 30 wk of age (in contrast to severe colitis in global IL-10KO mice). Protection from colitis in IL-10cKO mice was associated with an expanded population of IL-10-producing type 1 Tregs (Tr1, CD4+Foxp3-) in the colonic lamina propria that produced more IL-10 on a per-cell basis compared with wild-type intestinal Tr1 cells. Collectively, our findings reveal a role for Tr1 cells in the gut, as they expand to fill a tolerogenic niche in conditions of suboptimal Foxp3+ Treg-mediated suppression and provide functional protection against experimental colitis.

Interleukin-10 Knockout Mice Do Not Reliably Exhibit Macroscopic Inflammation: A Natural History Endoscopic Surveillance Study

BACKGROUND

Interleukin (IL)-10 knockout (KO) mice, a model for inflammatory bowel disease (IBD), develop chronic enterocolitis due to an aberrant immune response to enteric antigens. Endoscopy, the gold standard for evaluation of human mucosal health, is not widely available for murine models.

AIMS

To assess the natural history of left-sided colitis in IL-10 KO mice via serial endoscopies.

METHODS

BALB/cJ IL-10 KO mice underwent regular endoscopic assessments from 2 up to 8 months of age. Procedures were recorded and blindly evaluated using a 4-component endoscopic score: mucosal wall transparency, intestinal bleeding, focal lesions and perianal lesions (0-3 points each). An endoscopic score ≥ 1 point was considered as the presence of colitis/flare.

RESULTS

IL-10 KO mice (N = 40, 9 female) were assessed. Mean age at first endoscopy was 62.5 ± 2.5 days; average number of procedures per mouse was 6.0 ± 1.3. A total of 238 endoscopies were conducted every 24.8 ± 8.3 days, corresponding to 124.1 ± 45.2 days of surveillance per mouse. Thirty-three endoscopies in 24 mice (60%) detected colitis, mean endoscopy score 2.5 ± 1.3 (range: 1-6.3). Nineteen mice (47.5%) had one episode of colitis and 5 (12.5%) had 2-3 episodes. All exhibited complete spontaneous healing on subsequent endoscopies.

CONCLUSIONS

In this large-scale endoscopic surveillance study of IL-10 KO mice, 40% of mice did not develop endoscopic left-sided colitis. Furthermore, IL-10 KO mice did not exhibit persistent colitis and universally exhibited complete spontaneous healing without treatment. The natural history of colitis in IL-10 KO mice may not be comparable with that of IBD in humans and requires careful consideration.

The Loss of YTHDC1 in Gut Macrophages Exacerbates Inflammatory Bowel Disease

The nuclear N6 -methyladenosine (m6 A) reader YT521-B homology-domain-containing protein 1 (YTHDC1) is required to maintain embryonic stem cell identity. However, little is known about its biological functions in intestinal-resident macrophages and inflammatory bowel disease (IBD). Herein, it is demonstrated that macrophage-specific depletion or insufficiency of YTHDC1 accelerates IBD development in animal models. On the molecular basis, YTHDC1 reduction in IBD-derived macrophages is attributed to Zinc finger protein 36 (ZFP36)-induced mRNA degradation. Importantly, transcriptome profiling and mechanistic assays unveil that YTHDC1 in macrophages regulates Ras homolog family member H (RHOH) to suppress inflammatory responses and fine-tunes NME nucleoside diphosphate kinase 1 (NME1) to enhance the integrity of colonic epithelial barrier, respectively. Collectively, this study identifies YTHDC1 as an important factor for the resolution of inflammatory responses and restoration of colonic epithelial barrier in the setting of IBD.

Astragalus polysaccharides alleviate type 1 diabetes via modulating gut microbiota in mice

Type 1 diabetes (T1D) is a serious health problem that needs to be addressed worldwide. Astragalus polysaccharides (APS), the main chemical components of Astragali Radix, have anti-diabetic activity. As most plant polysaccharides are difficult to digest and absorb, we hypothesised that APS exert hypoglycaemic effects through the gut. This study intends to investigate the modulation of T1D associated with gut microbiota by neutral fraction of Astragalus polysaccharides (APS-1). T1D mice were induced with streptozotocin and then treated with APS-1 for 8 weeks. Fasting blood glucose levels were decreased and the insulin levels were increased in T1D mice. The results demonstrated that APS-1 improved gut barrier function by regulating ZO-1, Occludin and Claudin-1 expression, and reconstructed gut microbiota by increasing the relative abundance of Muribaculum, Lactobacillus and Faecalibaculum. In addition, APS-1 significantly increased the levels of acetic acid, propionic acid, butyric acid and inhibited the expression of pro-inflammatory factors IL-6 and TNF-α in T1D mice. Further exploration revealed that APS-1 alleviation of T1D may be associated with short-chain fatty acids (SCFAs)-producing bacteria, and that SCFAs binds to GPRs and HDACs proteins and modulate the inflammatory responses. In conclusion, the study supports the potential of APS-1 as a therapeutic agent for T1D.

Wheat Germ Supplementation Reduces Inflammation and Gut Epithelial Barrier Dysfunction in Female Interleukin-10 Knockout Mice Fed a Pro-Atherogenic Diet

BACKGROUND

Mice lacking IL-10 are prone to gut inflammation. Additionally, decreased production of short-chain fatty acids (SCFAs) plays a significant role in the high-fat (HF) diet-induced loss of gut epithelial integrity. We have previously shown that wheat germ (WG) supplementation increased ileal expression of IL-22, an important cytokine in maintaining gut epithelial homeostasis.

OBJECTIVES

This study investigated the effects of WG supplementation on gut inflammation and epithelial integrity in IL-10 knockout mice fed a pro-atherogenic diet.

METHODS

Eight-week-old female C57BL/6 wild type mice were fed a control diet (10% fat kcal), and age-matched knockout mice were randomly assigned to 1 of 3 diets (n = 10/group): control, high-fat high-cholesterol (HFHC) [(43.4% fat kcal (∼49% saturated fat, 1% cholesterol)], or HFHC + 10% WG (HFWG) for 12 wk. Fecal SCFAs and total indole, ileal, and serum proinflammatory cytokines, gene or protein expression of tight junctions, and immunomodulatory transcription factors were assessed. Data were analyzed by 1-way ANOVA, and P < 0.05 was considered statistically significant.

RESULTS

Fecal acetate, total SCFAs, and indole increased (P < 0.05) by at least 20% in HFWG compared with the other groups. WG increased (P < 0.0001, 2-fold) ileal Il22 (interleukin 22) to Il22ra2 (interleukin 22 receptor, alpha 2) mRNA ratio and prevented the HFHC diet-mediated increase in ileal protein expression of indoleamine 2,3 dioxygenase and pSTAT3 (phosphorylated signal transducer and activator of transcription 3). WG also prevented the HFHC diet-mediated reduction (P < 0.05) in ileal protein expression of the aryl hydrocarbon receptor and the tight junction protein, zonula occludens-1. Serum and ileal concentrations of the proinflammatory cytokine, IL-17, were lower (P < 0.05) by at least 30% in the HFWG group than in the HFHC group.

CONCLUSIONS

Our findings demonstrate that the anti-inflammatory potential of WG in IL-10 KO mice consuming an atherogenic diet is partly attributable to its effects on the IL-22 signaling and pSTAT3-mediated production of T helper 17 proinflammatory cytokines.

Akkermansia deficiency and mucin depletion are implicated in intestinal barrier dysfunction as earlier event in the development of inflammation in interleukin-10-deficient mice

BACKGROUND

Dysbiosis and mucin depletion are related with intestinal barrier dysfunction and seems to be an early pathophysiological event in inflammatory bowel disease (IBD). The objective of this work is to study these parameters in the natural history of colitis in IL-10 deficient mice (IL-10-/-).

METHODS

Wild type (WT) and IL-10-/-. mice were followed until sacrifice at 3, 5, 10, 20, 57, and 70 weeks. Body weight, colonic weight/length ratio and in vivo intestinal permeability were registered. Expression of inflammatory and adhesion molecules in the colon was explored by qPCR as Mucin-2 (MUC-2) and molecules involved in goblet cell maturation Interleukin-18 (IL-18) and WAP Four-Disulfide Core Domain 2 (WFDC2), the endoplasmic reticulum stress markers X-box-binding protein (Xbp-1) and Reticulon-4B (RTN-4B). Bacterial composition in feces and colonic mucosa was determined by massive sequencing of the V3-V4 regions of 16S rDNA gene.

RESULTS

IL-10-/- mice showed histological inflammation at weeks 20 and 57, but most notably the intestinal permeability was significantly higher from week 10. Concordantly, the number of goblet cells and expression of MUC-2, IL-18, WFDC2 and Xbp-1 were significantly lower in KO from week 10. Nevertheless, no significant differences were found in the mRNA expression of MUC-2 or Xbp-1 between both groups-derived colon organoids. Significant bacterial differences began at week 5, being the Akkermansia deficiency in KO the most relevant result.

CONCLUSION

Gut microbiota alterations and mucin depletion are associated with early intestinal barrier dysfunction and precede overt gut inflammation in this animal model of IBD.

Updates of cancer hallmarks in patients with inborn errors of immunity

PURPOSE OF REVIEW

The development of cancer in patients with genetically determined inborn errors of immunity (IEI) is much higher than in the general population. The hallmarks of cancer are a conceptualization tool that can refine the complexities of cancer development and pathophysiology. Each genetic defect may impose a different pathological tumor predisposition, which needs to be identified and linked with known hallmarks of cancer.

RECENT FINDINGS

Four new hallmarks of cancer have been suggested, recently, including unlocking phenotypic plasticity, senescent cells, nonmutational epigenetic reprogramming, and polymorphic microbiomes. Moreover, more than 50 new IEI genes have been discovered during the last 2 years from which 15 monogenic defects perturb tumor immune surveillance in patients.

SUMMARY

This review provides a more comprehensive and updated overview of all 14 cancer hallmarks in IEI patients and covers aspects of cancer predisposition in novel genes in the ever-increasing field of IEI.

Inflammatory bowel disease addressed by Caco-2 and monocyte-derived macrophages: an opportunity for an in vitro drug screening assay

Inflammatory bowel disease (IBD) is a widespread disease, affecting a growing demographic. The treatment of chronic inflammation located in the GI-tract is dependent on the severity; therefore, the IBD treatment pyramid is commonly applied. Animal experimentation plays a key role for novel IBD drug development; nevertheless, it is ethically questionable and limited in its throughput. Reliable and valid in vitro assays offer the opportunity to overcome these limitations. We combined Caco-2 with monocyte-derived macrophages and exposed them to known drugs, targeting an in vitro-in vivo correlation (IVIVC) with a focus on the severity level and its related drug candidate. This co-culture assay addresses namely the intestinal barrier and the immune response in IBD. The drug efficacy was analyzed by an LPS-inflammation of the co-culture and drug exposure according to the IBD treatment pyramid. Efficacy was defined as the range between LPS control (0%) and untreated co-culture (100%) independent of the investigated read-out (TEER, Papp, cytokine release: IL-6, IL-8, IL-10, TNF-α). The release of IL-6, IL-8, and TNF-α was identified as an appropriate readout for a fast drug screening ("yes-no response"). TEER showed a remarkable IVIVC correlation to the human treatment pyramid (5-ASA, Prednisolone, 6-mercaptopurine, and infliximab) with an R2 of 0.68. Similar to the description of an adverse outcome pathway (AOP) framework, we advocate establishing an "Efficacy Outcome Pathways (EOPs)" framework for drug efficacy assays. The in vitro assay offers an easy and scalable method for IBD drug screening with a focus on human data, which requires further validation.

Supplementary Information

The online version contains supplementary material available at 10.1007/s44164-022-00035-8.

The lack of transcriptionally active Nrf2 triggers colon dysfunction in female mice - The role of estrogens

BACKGROUND AND AIM

The proper functioning of the gastrointestinal system relies on an intricate crosstalk between a plethora of cell types and signaling pathways. Recently we identified that the lack of NRF2 transcriptional activity (NRF2 tKO) triggers significant colon microscopical alterations, still they do not affect the general functioning of mice. Therefore, in this study, we aimed to address the gender-dependent impact of NRF2 transcriptional deficiency on colon function, and relate them to an established model of inflammatory bowel disease (IBD).

METHODS

In the study we subjected 3- and 6-month old mice deficient in IL-10 and NRF2 transcriptional activity and wild-type counterparts to tests assessing colon functionality, and histological analyses. To address the role of estrogens, we attempted to rescue the phenotype by the delivery of 17β-estradiol through subcutaneous implants.

RESULTS

In females, NRF2 transcriptional abrogation, like IL-10 deficiency, triggers a functional and microscopic phenotype, that resembles IBD. The females are significantly more affected by the dysfunctional phenotype, and the functional impairmentdecreases with age. We found that NRF2 transcriptional activity influences 17β-estradiol level and the estrogen receptors expression and location. Exogenous delivery of 17β-estradiol normalized colon motility in the NRF2 tKO mice, which is related to enhanced ERβ signaling.

CONCLUSIONS

Summing up, in this study, we underline that NRF2 transcriptional deficiency or the lack of IL-10 results in pronounced GI functional decline in young females. Mechanistically, we show that the impaired distal colon motility is dependent on ERβ signaling. Targeting estrogen signaling seems a promising therapeutic strategy to counteract colonic dysfunction.

Protective Effect of Dietary Polysaccharides from Yellow Passion Fruit Peel on DSS-Induced Colitis in Mice

Inflammatory bowel disease (IBD) is a complex inflammatory disorder characterized by chronic and spontaneously relapsing inflammation of the gastrointestinal tract. IBD includes two idiopathic disorders: Crohn’s disease (CD) and ulcerative colitis (UC). In particular, UC causes inflammation and ulceration of the colon and rectum. There is no cure for UC. The pharmacological treatment is aimed at controlling and/or reducing the inflammatory process and promoting disease remission. The present study investigated the possible protective effects of soluble dietary fiber (SDF) isolated from yellow passion fruit peel in the dextran sulfate sodium- (DSS-) induced colitis model in mice, induced by 5% of DSS. The animals were treated with SDF (10, 30, or 100 mg/kg (po)), and the disease activity index was monitored. Colon tissues were collected, measured, and prepared for oxidative stress, inflammation, and histology analysis. SDF improved body weight loss, colon length, and disease activity index and prevented colonic oxidative stress by regulating GSH levels and SOD activity. Furthermore, SDF reduced colonic MPO activity, TNF-α, and IL-1β levels and increased IL-10 and IL-6 levels. As observed by histological analysis, SDF treatment preserved the colonic tissue, the mucus barrier, and reduced inflammatory cell infiltration. Although this is a preliminary study, taken together, our data indicate that SDF may improve the course of DSS-UC. More studies are needed to explore and understand how SDF promotes this protection.

IL-10 regulates Th17 response to inhibit hepatobiliary injury caused by Clonorchis sinensis infection in C57BL/6J mice

Clonorchiasis caused by Clonorchis sinensis is a mainly foodborne parasitic disease. It can lead to hepatobiliary duct inflammation, fibrosis, obstructive jaundice, liver cirrhosis, and even cholangiocarcinoma. Interleukin (IL)-10 is an immune-regulatory cytokine which plays an immunosuppressive role during infection. Our previous study found that IL-10 was increased in mice with C. sinensis infection. However, the role and mechanism of IL-10 playing in hepatobiliary injury induced by C. sinensis infection remain unknown. Herein, Il10^+/+ mice and Il10^+/- C57BL/6J mice were infected with C. sinensis. It was found that IL-10 deficiency aggravated biliary hyperplasia and exacerbated periductal fibrosis induced by C. sinensis infection. Moreover, IL-10 deficiency increased CD4⁺T cells and CD8⁺T cells but not macrophages in the liver of mice with infection. There were no apparent differences in Th1 and Treg cells between Il10^+/+ and Il10^+/- mice infected with C. sinensis. However, the proportion of Th17 cells in CD4⁺T cells in Il10^+/- infected mice was significantly higher than that in Il10^+/+ infected mice. IL-10 deficiency also enhanced the increase of Th17 cells induced by ESPs stimulation in vitro. Taken together, our results suggest that IL-10 plays a protective role in hepatobiliary injury in C57BL/6J mice induced by C. sinensis infection via inhibiting Th17 cells, which could deepen our understanding of the immunopathology of clonorchiasis.

CD11c+ myeloid cell exosomes reduce intestinal inflammation during colitis

Intercellular communication is critical for homeostasis in mammalian systems, including the gastrointestinal (GI) tract. Exosomes are nanoscale lipid extracellular vesicles that mediate communication between many cell types. Notably, the roles of immune cell exosomes in regulating GI homeostasis and inflammation are largely uncharacterized. By generating mouse strains deficient in cell-specific exosome production, we demonstrate deletion of the small GTPase Rab27A in CD11c+ cells exacerbated murine colitis, which was reversible through administration of DC-derived exosomes. Profiling RNAs within colon exosomes revealed a distinct subset of miRNAs carried by colon- and DC-derived exosomes. Among antiinflammatory exosomal miRNAs, miR-146a was transferred from gut immune cells to myeloid and T cells through a Rab27-dependent mechanism, targeting Traf6, IRAK-1, and NLRP3 in macrophages. Further, we have identified a potentially novel mode of exosome-mediated DC and macrophage crosstalk that is capable of skewing gut macrophages toward an antiinflammatory phenotype. Assessing clinical samples, RAB27A, select miRNAs, and RNA-binding proteins that load exosomal miRNAs were dysregulated in ulcerative colitis patient samples, consistent with our preclinical mouse model findings. Together, our work reveals an exosome-mediated regulatory mechanism underlying gut inflammation and paves the way for potential use of miRNA-containing exosomes as a novel therapeutic for inflammatory bowel disease.

Analysis of the Effects of Ninjin’yoeito on Physical Frailty in Mice

Physical frailty is an aging-related clinical syndrome involving decreases in body weight, mobility, activity, and walking speed that occurs in individuals with sarcopenia and is accelerated by increased oxidative stress. Ninjin’yoeito, a traditional Japanese Kampo medicine, is used for treating conditions, including anemia and physical weakness. Here, we investigated whether ninjin’yoeito could improve physical frailty by controlling oxidative stress in the senescence-accelerated mouse prone 8 (SAMP8) model. First, SAMP8 mice were divided into two groups, ninjin’yoeito treated and untreated, with the former consuming a diet containing 3% ninjin’yoeito from 3 months of age. At 7 months of age, body weight, motor function, locomotor activity, and mean walking speed were measured. Subsequently, mice were euthanized and measured for muscle weight, 8-hydroxy-2′-deoxyguanosine levels in muscle and brain, and cleaved caspase-3 expression in brain. The results showed reductions in weight, locomotor function, locomotion, and average walking speed in the untreated group, which were significantly improved by ninjin’yoeito. Furthermore, 8-hydroxy-2′-deoxyguanosine levels were reduced in muscle and brain from ninjin’yoeito-treated mice, compared with the levels in untreated mice; cleaved caspase-3 expression was similarly reduced in brain from the treated mice, indicating reduced apoptosis. Our findings suggest that ninjin’yoeito inhibits sarcopenia-based physical frailty through its antioxidant effects.

Effect of milk protein hydrolysate supplementation on protein energy malnutrition-induced gut dysbiosis

Dairy proteins in the diet are beneficial for the growth of probiotics; however, what is unknown is the gut-mediated immune responses under protein energy malnutrition (PEM) and if dairy protein hydrolysates can be effective as dietary interventions. This study compares the composition of the gut microbiota of rats with moderate protein deficiency (M.PEM) and severe protein deficiency (S.PEM) induced by feeding 5% and 1% hypoprotein diets, followed by replenishment with buffalo and whey protein hydrolysates. Fecal samples were collected, and the composition of the gut bacteria was analyzed by whole genome sequencing using long-read sequencing. Gene expression studies of the immunomodulatory cytokines involved and quantification of sIgA were carried out. IL-6 and IFN-γ were downregulated by about 0.17 ± 0.06 and 0.12 ± 0.10 fold when supplemented with whey protein hydrolysate in SP-RWC rats and by about 0.02 ± 0.06 and 0.35 ± 0.12 fold when using buffalo milk hydrolysate. The percentage of Firmicutes decreased in M.PEM and S.PEM rats (33.57%, 28.83 versus 47.73% of control at 3 weeks) but increased upon protein replenishment for all three protein sources at the end of nine weeks. The percentage of Bacteroidetes increased to 31.03% in S.PEM-induced rats as against 28.17% in control rats. The relative abundance of Lactobacillus sp. decreased in M.PEM and S.PEM rats while it showed the opposite effect upon protein replenishment. Gut microbiota modulated the pathogenesis of PEM differentially based on protein intervention along with a significant increase in the relative abundance of the keystone Lactobacillus genus.

Emerging strategies in targeting tumor-resident myeloid cells for cancer immunotherapy

Immune checkpoint inhibitors targeting programmed cell death protein 1, programmed death-ligand 1, and cytotoxic T-lymphocyte-associated protein 4 provide deep and durable treatment responses which have revolutionized oncology. However, despite over 40% of cancer patients being eligible to receive immunotherapy, only 12% of patients gain benefit. A key to understanding what differentiates treatment response from non-response is better defining the role of the innate immune system in anti-tumor immunity and immune tolerance. Teleologically, myeloid cells, including macrophages, dendritic cells, monocytes, and neutrophils, initiate a response to invading pathogens and tissue repair after pathogen clearance is successfully accomplished. However, in the tumor microenvironment (TME), these innate cells are hijacked by the tumor cells and are imprinted to furthering tumor propagation and dissemination. Major advancements have been made in the field, especially related to the heterogeneity of myeloid cells and their function in the TME at the single cell level, a topic that has been highlighted by several recent international meetings including the 2021 China Cancer Immunotherapy workshop in Beijing. Here, we provide an up-to-date summary of the mechanisms by which major myeloid cells in the TME facilitate immunosuppression, enable tumor growth, foster tumor plasticity, and confer therapeutic resistance. We discuss ongoing strategies targeting the myeloid compartment in the preclinical and clinical settings which include: (1) altering myeloid cell composition within the TME; (2) functional blockade of immune-suppressive myeloid cells; (3) reprogramming myeloid cells to acquire pro-inflammatory properties; (4) modulating myeloid cells via cytokines; (5) myeloid cell therapies; and (6) emerging targets such as Siglec-15, TREM2, MARCO, LILRB2, and CLEVER-1. There is a significant promise that myeloid cell-based immunotherapy will help advance immuno-oncology in years to come.

Inflammatory Bowel Disease: A Review of Pre-Clinical Murine Models of Human Disease

Crohn’s disease (CD) and ulcerative colitis (UC) are both highly inflammatory diseases of the gastrointestinal tract, collectively known as inflammatory bowel disease (IBD). Although the cause of IBD is still unclear, several experimental IBD murine models have enabled researchers to make great inroads into understanding human IBD pathology. Here, we discuss the current pre-clinical experimental murine models for human IBD, including the chemical-induced trinitrobenzene sulfonic acid (TNBS) model, oxazolone and dextran sulphate sodium (DSS) models, the gene-deficient I-kappa-B kinase gamma (Iκκ-γ) and interleukin(IL)-10 models, and the CD4⁺ T-cell transfer model. We offer a comprehensive review of how these models have been used to dissect the etiopathogenesis of disease, alongside their limitations. Furthermore, the way in which this knowledge has led to the translation of experimental findings into novel clinical therapeutics is also discussed.

A high salt diet protects interleukin 10-deficient mice against chronic colitis by improving the mucosal barrier function

A high salt diet (HSD) is often associated with a high risk for a variety of diseases, such as obesity and cardiovascular disease. Previous studies have demonstrated that an HSD enhances Th17 responses and increases the severity of autoimmune diseases. In this study, we investigated the effects of HSD (4% NaCl w/w) on colitis in IL-10^-/- mice by comparing it with IL-10^-/- mice on a normal salt diet (NSD, 1% NaCl w/w). The colonic epithelial barrier integrity in IL-10^-/- mice, as well as differentiated Caco-2 cells exposed to high NaCl and proinflammatory cytokines, was also evaluated. Surprisingly, an HSD significantly ameliorated macroscopic colitis, improved the intestinal permeability of FITC-dextran, and decreased multiple proinflammatory cytokines in the colonic mucosa of IL-10^-/- mice. While occludin and claudin-1, two major tight-junction proteins, were markedly down-regulated in IL-10^-/- mice, HSD effectively restored their expressions. In Caco-2 cells, proinflammatory cytokines (TNF-α and IL-1β) potently decreased the expression of occludin and claudin-1 regardless of salt conditions [0.9% (standard), 1.2%, or 1.5% NaCl]. Under high salt conditions (1.5% NaCl), transepithelial electrical resistance (TEER) was elevated, while the addition of IL-10 further downregulated occludin and claudin-1 expressions by ~50% and lowered TEER. These findings suggest that, in the absence of IL-10, HSD promotes intestinal epithelial integrity and exerts an anti-inflammatory role as demonstrated by alleviated colitis in IL-10^-/- mice. Moreover, Caco-2 data indicate that, in an inflammatory environment and under high NaCl conditions, IL-10 may play a proinflammatory role by disrupting colonic epithelial integrity and thus further promoting inflammation.