High resolution colonoscopy in live mice

Selective H2-O tissue expression reduces risk for graft-versus-host disease in an in vivo transplantation model

BACKGROUND

Allogeneic stem cell transplantation (aSCT) is frequently used to treat patients with hematological malignancies. The therapeutic effect relies mainly on the graft-versus-leukemia (GvL) effect, in which donor T-cells eliminate residual malignant cells. Unfortunately, the beneficial GvL is often accompanied by detrimental graft-versus-host disease (GvHD). A successful separation of both effects could not yet be achieved. In previous work, we identified two groups of HLA-class II restricted antigens depending on their behavior towards HLA-DM. DM-resistant antigens are presented in the presence of HLA-DM, whereas presentation of DM-sensitive antigens relies on the inhibitory molecule HLA-DO. Due to the unique expression pattern of HLA-DO, DM sensitive antigens cannot be presented efficiently by non-hematopoietic cells even under inflammatory conditions. This suggests that CD4+ T-cells directed against DM-sensitive antigens may be able to separate GvL from GvHD.

OBJECTIVE

In this study, we wanted to demonstrate convincingly that HLA-DO expression strongly influences the severity of GvHD in allogeneic stem cell transplantation.

METHODS

Therefore, we generated a modified CD4 donor lymphocyte infusion (DLI) depleted of CD4+ T-cells directed against DM resistant antigens to address its potential to induce GvHD in an in vivo MHC mismatch transplantation model in dependency on selective tissue expression of H2-O using H2-O wildtype, knockout and transgenic recipients.

RESULTS

Intriguingly, we could demonstrate that our modified CD4 DLI targeting DM-sensitive antigens only induced mild GvHD in wildtype recipients with endogenous selective H2-O expression and none in H2-O knockouts, while assessing the immunogenic potential of DM-sensitive antigens in H2-O transgenic recipients.

CONCLUSION

The results of the present work provide evidence that DM-resistant antigens are main targets of GvHD and addressing DM-sensitive antigens might be a promising tool to improve outcome after aSCT by separating GvL from GvHD.

Stromal Cell Subsets Show Model-Dependent Changes in Experimental Colitis and Affect Epithelial Tissue Repair and Immune Cell Activation

BACKGROUND

Previous work on inflammatory bowel disease (IBD) revealed changes in the abundance of colonic stromal subsets during intestinal inflammation. However, it is currently unknown whether these stromal cell subset changes are also reflected in different IBD mouse models and how commonly used IBD therapies affect stromal cell subset composition.

METHODS

Stromal subset markers CD55, C-X-C motif chemokine 12 (CXCL12), podoplanin (PDPN), CD90, and CD73 were analyzed by flow cytometry in 3 mouse models for IBD, namely interleukin (IL)-10 knockout (KO), dextran sulfate sodium-induced, and T-cell transfer model for colitis. Next, the effects of IBD therapies on the stromal subset composition were studied. In vitro experiments were performed to study the interaction between stromal cell subsets and epithelial/immune cells.

RESULTS

The colitis-induced changes in the abundance of stromal cell subsets differed considerably between the 3 colitis mouse models. Interestingly, treatment with IBD medication affected specific stromal subsets in a therapy and model-specific manner. In vitro experiments showed that specific stromal subsets affected epithelial wound healing and/or T-cell activation.

CONCLUSIONS

The relative abundance changes of stromal cell subsets during experimental colitis differ between 3 established colitis models. Treatment with IBD therapies influences stromal subset abundance, indicating their importance in IBD pathogenesis, possibly through affecting epithelial migration, and T-cell activation.

Enhancement of colorectal cancer therapy through interruption of the HSF1-HSP90 axis by p53 activation or cell cycle inhibition

The stress-associated chaperone system is an actionable target in cancer therapies. It is ubiquitously upregulated in cancer tissues and enables tumorigenicity by stabilizing oncoproteins. Most inhibitors target the key component, heat-shock protein 90 (HSP90). Although HSP90 inhibitors are highly tumor-selective, they fail in clinical trials. These failures are partly due to interference with a negative regulatory feedback loop in the heat-shock response (HSR): in response to HSP90 inhibition, there is compensatory synthesis of stress-inducible chaperones, mediated by the transcription factor heat-shock-factor 1 (HSF1). We recently identified that wild-type p53 reduces the HSR by repressing HSF1 via a p21-CDK4/6-MAPK-HSF1 axis. Here, we test whether in HSP90-based therapies, simultaneous p53 activation or direct cell cycle inhibition interrupts the deleterious HSF1-HSR axis and improves the efficiency of HSP90 inhibitors. We found that the clinically relevant p53 activator Idasanutlin suppresses the HSF1-HSR activity in HSP90 inhibitor-based therapies. This combination synergistically reduces cell viability and accelerates cell death in p53-proficient colorectal cancer (CRC) cells, murine tumor-derived organoids, and patient-derived organoids (PDOs). Mechanistically, upon combination therapy, CRC cells upregulate p53-associated pathways, apoptosis, and inflammatory pathways. Likewise, in a CRC mouse model, dual HSF1-HSP90 inhibition represses tumor growth and remodels immune cell composition. Importantly, inhibition of the cyclin-dependent kinases 4/6 (CDK4/6) under HSP90 inhibition phenocopies synergistic repression of the HSR in p53-proficient CRC cells. Moreover, in p53-deficient CRC cells, HSP90 inhibition in combination with CDK4/6 inhibitors similarly suppresses the HSF1-HSR and reduces cancer growth. Likewise, p53-mutated PDOs respond to dual HSF1-HSP90 inhibition, providing a strategy to target CRC independent of the p53 status. In sum, we provide new options to improve HSP90-based therapies to enhance CRC therapies.

Oral Lipid-Based Nanomedicine for the Inhibition of the cGAS-STING Pathway in Inflammatory Bowel Disease Treatment

Harnessing the effect of the cyclic GMP-AMP Synthase-STimulator of INterferon Genes (cGAS-STING) signaling pathway has emerged as a promising approach to developing novel strategies for the oral treatment of inflammatory bowel disease (IBD). In this work, we screened different cGAS-STING inhibitors in vitro in murine macrophages. Then, we encapsulated the cGAS-STING inhibitor H-151 within lipid nanocapsules (LNCs), owing to their inherent ability to induce the secretion of glucagon-like peptide 2 (GLP-2), a re-epithelizing peptide, upon oral administration. We demonstrated that our formulation (LNC(H-151)) could induce GLP-2 secretion and selectively target the cGAS-STING pathway and its downstream key markers (including TBK1 and pTBK1) while reducing the expression of pro-inflammatory cytokines associated with the cGAS-STING pathway (TNF-α and CXCL10) in murine macrophages. In an in vivo acute dextran sodium sulfate (DSS)-induced colitis mouse model, the oral administration of LNC(H-151) significantly reduced pro-inflammatory cytokines to levels comparable to the CTRL Healthy group while promoting mucosal healing. The therapeutic potential of this scalable and cost-effective nanomedicine warrants further investigation as an alternative for the oral treatment of IBD.

Sakuranetin ameliorates experimental colitis in a gut microbiota-dependent manner

BACKGROUND

The progression of inflammatory bowel disease (IBD) is closely connected with intestinal flora dysbiosis. Sakuranetin (SAK) is a natural compound with anti-inflammatory and antibiosis activities. We investigated the properties and mechanisms of SAK on IBD-like colitis.

METHODS

Mice with dextran sulfate sodium (DSS)-induced colitis were accomplished to assess the effects of SAK on colitis, as well as intestinal mucosal immune imbalance and intestinal barrier dysfunction. 16S rDNA was used to characterize the intestinal flora, and the short-chain fatty acid (SCFA) content in faeces was calculated using GS‒MS. Faecal microbiota transplantation (FMT) and a pseudosterile model (antibiotic cocktail, ABX) were used to evaluate whether the effects of SAK on colitis were dependent on the gut flora. Pathohistological and biochemical tests were used to estimate the safety of SAK.

RESULTS

SAK significantly ameliorated DSS-induced colitis in mice, verified by decreased weight loss, less colon shortening, and lower disease activity, histology and colonoscopy scores. Moreover, SAK alleviated gut dysbiosis and elevated the abundance of SCFA-producing bacteria in DSS-treated mice. Meanwhile, SAK increased faecal SCFA levels and activated GPR41/43 signalling. SAK also improved Treg/Th17 homeostasis and intestinal barrier function. In addition, ABX and FMT experiments confirmed that the ability of SAK to alleviate colitis was mediated through the gut flora. Finally, a safety experiment revealed that SAK had no significant adverse effects on major organ or liver/kidney function.

CONCLUSIONS

SAK may improve the intestinal immune balance and barrier function by regulating intestinal flora dysbiosis and increasing SCFA production, thereby protecting against colitis.

TIFA renders intestinal epithelial cells responsive to microbial ADP-heptose and drives colonic inflammation in mice

Intestinal immune homeostasis relies on intestinal epithelial cells (IECs), which provide an efficient barrier, and warrant a state of tolerance between the microbiome and the mucosal immune system. Thus, proper epithelial microbial sensing and handling of microbes is key to preventing excessive immunity, such as seen in patients with inflammatory bowel disease (IBD). To date, the molecular underpinnings of these processes remain incompletely understood. This study identifies TIFA as a driver of intestinal inflammation and an epithelial signaling hub between the microbiome and mucosal immune cells. TIFA was constitutively expressed in crypt epithelial cells and was highly induced in the intestine of mice and IBD patients with intestinal inflammation. We further identified IL-22 signaling via STAT3 as key mechanism driving TIFA expression in IECs. At the molecular level, we demonstrate that TIFA expression is essential for IEC responsiveness to the bacterial metabolite ADP-heptose. Most importantly, ADP-heptose-induced TIFA signaling orchestrates an inflammatory cellular response in the epithelium, with NF-κB and inflammasome activation, and high levels of chemokine production. Finally, mice lacking TIFA were protected from intestinal inflammation when subjected to a model of experimental colitis. In conclusion, our study implicates that targeting TIFA may be a strategy for future IBD therapy.

Elucidating a Tumor-Selective Nanoparticle Delivery Mechanism at the Colorectal Lumen-Tumor Interface for Precise Local Cancer Therapy

Although various colorectal cancer (CRC)-targeted nanoparticles have been developed to selectively deliver anticancer agents to tumor tissues, severe off-target side effects still persist due to unwanted systemic nanoparticle distribution, limiting the therapeutic outcome. Here, by elucidating a tumor-selective nanoparticle delivery mechanism occurring at the colorectal lumen-tumor interface, an alternative CRC-targeted delivery route is proposed, which enables highly tumor-selective delivery without systemic distribution, through direct drug delivery from the outside of the body (colorectal lumen) to tumors in the colorectum. Owing to the presence of accessible tumor-specific receptors such as CD44 at the colorectal lumen-tumor interface, but not at the colorectal lumen-normal tissue interface, colorectal luminal surface (CLS)-targeting ligand-functionalized nanoparticles selectively accumulate in CRC tissues without systemic distribution, resulting in successful local CRC therapy. The findings suggest that CLS-targeted lumen-to-tumor delivery can be a suitable strategy for highly CRC-specific drug delivery for precise local CRC therapy.

Epstein-Barr virus infection exacerbates ulcerative colitis by driving macrophage pyroptosis via the upregulation of glycolysis

Background

Epstein-Barr virus (EBV) infection is associated with clinical symptoms, treatment response, need for surgical intervention, and an enhanced likelihood of lymphoma among patients with ulcerative colitis (UC). However, existing studies have primarily concentrated on the epidemiological and clinical associations between EBV and UC, leaving the mechanisms by which EBV exacerbates colitis poorly understood.

Methods

Clinical specimens of UC patients with EBV infection and a mouse model of dextran sulfate sodium-induced colitis with concurrent murine γ-herpesvirus 68 (MHV-68) infection were utilized to investigate the relationship between EBV infection and macrophage pyroptosis. In vivo, adoptive transfer of MHV-68-induced macrophages and macrophage depletion were performed to elucidate the underlying mechanisms. In vitro, myeloid leukemia mononuclear cells of human (THP-1) and macrophages derived from mouse bone marrow (BMDMs) were stimulated with EBV and MHV-68, respectively, to assess macrophage pyroptosis and glycolysis.

Results

EBV-induced activation of macrophage pyroptosis was positively correlated with clinical disease activity in UC patients. Furthermore, MHV-68 infection activated pyroptosis by upregulating gasdermin D, NLRP3, interleukin-1β, and interleukin-18 in colonic tissues and peritoneal macrophages of mice with colitis. In vitro, EBV and MHV-68 also mediated activation of pyroptosis in human THP-1 cells and mouse BMDMs, respectively. Additionally, the adoptive transfer of MHV-68-induced BMDMs aggravated murine colitis, whereas macrophage depletion attenuated MHV-68-induced intestinal injury. Mechanistically, MHV-68 promoted macrophage pyroptosis by upregulating glycolysis, while the glycolysis inhibitor, 2-deoxy-D-glucose, blocked this process in vitro.

Conclusion

EBV infection exacerbates UC by driving macrophage pyroptosis through upregulation of glycolysis, indicating a potential therapeutic approach to mitigate EBV-induced intestinal inflammation.

Glepaglutide-Loaded Foam for the Induction of Mucosal Healing in the Treatment of Inflammatory Bowel Disease

Glucagon-like peptide 2 (GLP-2) stimulates intestinal growth, repairs mucosa, and enhances epithelial integrity but has a short half-life (7 min). Glepaglutide (GL), a GLP-2 analog with an extended half-life (50 h), is currently undergoing clinical trials for patients with short bowel syndrome. GL requires subcutaneous injection, which poses challenges for potential patient compliance. To address this challenge, GL was loaded into a rectal foam formulation using CO2 as a permeation enhancer to combine both the local and systemic effects of the GLP-2 analog. In a dextran sodium sulfate (DSS)-induced colitis model, the GL-loaded foam (GLF) significantly mitigated the severity of colitis. GLF facilitated mucosal healing, as evidenced by colonoscopy images, increased plasma markers of mucosal healing, and increased crypt depth. To evaluate GL absorption in the colon, fluorescein dextran 4K (FD 4K) was employed. The foam formulation improved macromolecule absorption in the colon, with fast recovery of enhanced permeation that dissipated after 4 h. This study highlights GLF as a promising formulation for GL administration, balancing systemic and local anti-inflammatory effects.

S1PR1-biased activation drives the resolution of endothelial dysfunction-associated inflammatory diseases by maintaining endothelial integrity

G protein-coupled sphingosine-1-phosphate receptor 1 (S1PR1), a drug target for inflammatory bowel disease (IBD), enables immune cells to egress from lymph nodes, but the treatment increases the risk of immunosuppression. The functional signaling pathway triggered by S1PR1 activation in endothelial cells and its therapeutic application remains unclear. Here, we showed that S1PR1 is highly expressed in endothelial cells of IBD patients and positively correlated with endothelial markers. Gi-biased agonist-SAR247799 activated S1PR1 and reversed pathology in male mouse and organoid IBD models by protecting the integrity of the endothelial barrier without affecting immune cell egress. Cryo-electron microscopy structure of S1PR1-Gi signaling complex bound to SAR247799 with a resolution of 3.47 Å revealed the recognition mode for the biased ligand. With the efficacy of SAR247799 in treating other endothelial dysfunction-associated inflammatory diseases, our study offers mechanistic insights into the Gi-biased S1PR1 agonist and represents a strategy for endothelial dysfunction-associated disease treatment.

Salicylate-Elicited Activation of AMP-Activated Protein Kinase Directly Triggers Degradation of C-Myc in Colorectal Cancer Cells

Aspirin has consistently shown preventive effects in some solid cancers, notably colorectal cancer. However, the precise molecular mechanisms underlying this positive effect have remained elusive. In this study, we used an azoxymethane-induced mouse model of colon carcinogenesis to identify aspirin-associated molecular alterations that could account for its cancer-preventive effect. Transcriptomic analysis of aspirin-treated mice showed a strong reduction in c-Myc protein levels and effects on the Myc-dependent transcriptional program in colonic cells. Proto-oncogene c-Myc cooperates with AMP-activated protein kinase (AMPK) to control cellular energetics. Here, we show that salicylate, the active metabolite of aspirin, reduces c-Myc protein expression levels through multiple mechanisms that are both AMPK dependent and independent. This effect is cell-type dependent and occurs at both the transcriptional and post-translational levels. Salicylate-induced AMPK activation leads to the phosphorylation of c-Myc at Thr400, as well as its destabilization and degradation. Our results reveal a complex, multilayered, negative effect of salicylate on c-Myc protein abundance and suggest that chronic depletion of c-Myc can counteract the neoplastic transformation of colorectal epithelium, underpinning the preventive effect of aspirin on colorectal cancer.

Pharmacological Inhibition of N-Acylethanolamine Acid Amidase (NAAA) Mitigates Intestinal Fibrosis Through Modulation of Macrophage Activity

BACKGROUND AND AIMS

Intestinal fibrosis, a frequent complication of inflammatory bowel disease, is characterized by stricture formation with no pharmacological treatment to date. N-acylethanolamine acid amidase (NAAA) is responsible for the hydrolysis of acylethanolamides (AEs, eg, palmitoylethanolamide and oleoylethanolamide). Here, we investigated NAAA and AE signaling in gut fibrosis.

METHODS

NAAA and AE signaling were evaluated in human intestinal specimens from patients with stenotic Crohn's disease (CD). Gut fibrosis was induced by 2,4,6-trinitrobenzenesulfonic acid, monitored by colonoscopy, and assessed by qRT-PCR, histological analyses, and confocal microscopy. Immune cells in mesenteric lymph nodes were analyzed by FACS. Colonic fibroblasts were cultured in conditioned media derived from polarized or non-polarized bone marrow-derived macrophages (BMDMs). IL-23 signaling was evaluated by qRT-PCR, ELISA, FACS, and western blot in BMDMs and in lamina propria CX3CR1+ cells.

RESULTS

In ileocolonic human CD strictures, increased transcript expression of NAAA was observed with a decrease in its substrates oleoylethanolamide and palmitoylethanolamide. NAAA inhibition reduced intestinal fibrosis in vivo, as indicated by a decrease in inflammatory parameters, collagen deposition, and fibrosis-related genes, including those involved in epithelial-to-mesenchymal transition. More in-depth studies revealed modulation of the immune response related to IL-23 following NAAA inhibition. The antifibrotic actions of NAAA inhibition are mediated by Mφ and M2 macrophages that indirectly affect fibroblast collagenogenesis. NAAA inhibitor AM9053 normalized IL-23 signaling in BMDMs and in lamina propria CX3CR1+ cells.

CONCLUSIONS

Our findings provide new insights into the pathophysiological mechanism of intestinal fibrosis and identify NAAA as a promising target for the development of therapeutic treatments to alleviate CD-related fibrosis.

A communication pipeline for in vivo imaging core facilities

During the last years, the rapidly evolving imaging technologies have become valuable tools in in vivo research. Imaging modalities provide high resolution, real-time images and videos, offering the opportunity of longitudinal, quantitative, non-invasive/non-terminal monitoring of animal models. In parallel, in vivo imaging applications lead to animal reduction, by substituting phenotyping methods that require euthanasia. For in vivo imaging core facilities, effective communication is an essential tool that ensures that all teams involved are on the same page at all times. Successful communication is necessary at all stages and may be achieved via standardized procedures, which provide specifications and step-by-step instructions for all operations and activities. This article aims to provide a communication pipeline for imaging facilities operating with a full-service model, developed for 'Alexander Fleming' Animal Facilities, helping to achieve smooth operation and high-quality research.

E. Coli cytotoxic necrotizing factor-1 promotes colorectal carcinogenesis by causing oxidative stress, DNA damage and intestinal permeability alteration

BACKGROUND

Bacterial toxins are emerging as promising hallmarks of colorectal cancer (CRC) pathogenesis. In particular, Cytotoxic Necrotizing Factor 1 (CNF1) from E. coli deserves special consideration due to the significantly higher prevalence of this toxin gene in CRC patients with respect to healthy subjects, and to the numerous tumor-promoting effects that have been ascribed to the toxin in vitro. Despite this evidence, a definitive causal link between CNF1 and CRC was missing. Here we investigated whether CNF1 plays an active role in CRC onset by analyzing pro-carcinogenic key effects specifically induced by the toxin in vitro and in vivo.

METHODS

Viability assays, confocal microscopy of γH2AX and 53BP1 molecules and cytogenetic analysis were carried out to assess CNF1-induced genotoxicity on non-neoplastic intestinal epithelial cells. Caco-2 monolayers and 3D Caco-2 spheroids were used to evaluate permeability alterations specifically induced by CNF1, either in the presence or in the absence of inflammation. In vivo, an inflammatory bowel disease (IBD) model was exploited to evaluate the carcinogenic potential of CNF1. Immunohistochemistry and immunofluorescence stainings of formalin-fixed paraffin-embedded (FFPE) colon tissue were carried out as well as fecal microbiota composition analysis by 16 S rRNA gene sequencing.

RESULTS

CNF1 induces the release of reactive oxidizing species and chromosomal instability in non-neoplastic intestinal epithelial cells. In addition, CNF1 modifies intestinal permeability by directly altering tight junctions' distribution in 2D Caco-2 monolayers, and by hindering the differentiation of 3D Caco-2 spheroids with an irregular arrangement of these junctions. In vivo, repeated intrarectal administration of CNF1 induces the formation of dysplastic aberrant crypt foci (ACF), and produces the formation of colorectal adenomas in an IBD model. These effects are accompanied by the increased neutrophilic infiltration in colonic tissue, by a mixed pro-inflammatory and anti-inflammatory cytokine milieu, and by the pro-tumoral modulation of the fecal microbiota.

CONCLUSIONS

Taken together, our results support the hypothesis that the CNF1 toxin from E. coli plays an active role in colorectal carcinogenesis. Altogether, these findings not only add new knowledge to the contribution of bacterial toxins to CRC, but also pave the way to the implementation of current screening programs and preventive strategies.

Estrogen-related differences in antitumor immunity and gut microbiome contribute to sexual dimorphism of colorectal cancer

Colorectal cancer (CRC) is a multifaceted disease whose development and progression varies depending on tumor location, age of patients, infiltration of immune cells within cancer lesions, and the tumor microenvironment. These pathophysiological characteristics are additionally influenced by sex-related differences. The gut microbiome plays a role in initiation and progression of CRC, and shapes anti-tumor immune responses but how responsiveness of the immune system to the intestinal microbiota may contribute to sexual dimorphism of CRC is largely unknown. We studied survival, tumor-infiltrating immune cell populations and tumor-associated microbiome of a cohort of n = 184 male and female CRC patients through high-dimensional single-cell flow cytometry and 16S rRNA gene sequencing. We functionally tested the immune system-microbiome interactions in in-vivo and in-vitro models of the disease. High-dimensional single-cell flow cytometry showed that female patients are enriched by tumor-infiltrating invariant Natural Killer T (iNKT) cells but depleted by cytotoxic T lymphocytes. The enrichment of oral pathobionts and a reduction of β-glucuronidase activity are distinctive traits characterizing the gut microbiome of female patients affected by CRC. Functional assays using a collection of human primary iNKT cell lines demonstrated that the gut microbiota of female patients functionally impairs iNKT cell anti-tumor functions interfering with the granzyme-perforin cytotoxic pathway. Our results highlight a sex-dependent functional relationship between the gut microbiome, estrogen metabolism, and the decline of cytotoxic T cell responses, contributing to the sexual dimorphism observed in CRC patients with relevant implications for precision medicine and the design of targeted therapeutic approaches addressing sex bias in cancer.

The mesenteric adipokine SFRP5 alleviated intestinal epithelial apoptosis improving barrier dysfunction in Crohn's disease

The hypertrophic mesenteric adipose tissue (htMAT) of Crohn disease (CD) participates in inflammation through the expression of adipokines, but the exact mechanism of this action in the intestine is unknown. Here, we analyzed the expression of secreted frizzled-related protein 5 (SFRP5), an adipokine with cytoprotective effects, in htMAT and its role in CD. The results of this study revealed that the level of SFPR5 increased in the diseased MAT (htMAT) of CD patients and aggregated among intestinal epithelial cells in the diseased intestine and that it could ameliorate intestinal barrier dysfunction in tumor necrosis factor alpha (TNF-α)-stimulated colonic organoids and 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced mice at least in part through the inhibition of Wnt5a-mediated apoptosis in epithelial cells. This study elucidates possible mechanisms by which mesenteric adipokines influence the progression of enteritis and provides a new theoretical basis for the treatment of CD via the mesenteric pathway.

Inflammation-targeted delivery of Urolithin A mitigates chemical- and immune checkpoint inhibitor-induced colitis

Inflammatory bowel disease (IBD) treatment often involves systemic administration of anti-inflammatory drugs or biologics such as anti-TNF-α antibodies. However, current drug therapies suffer from limited efficacy due to unresponsiveness and adverse side effects. To address these challenges, we developed inflammation-targeting nanoparticles (ITNPs) using biopolymers derived from the gum kondagogu (Cochlospermum gossypium) plant. These ITNPs enable selective drug delivery to inflamed regions, offering improved therapeutic outcomes. We designed ITNPs that specifically bind to inflamed regions in both human and mouse intestines, facilitating more effective, uniform, and prolonged drug delivery within the inflamed tissues. Furthermore, we demonstrated that oral administration of ITNPs loaded with urolithin A (UroA), a microbial metabolite or its synthetic analogue UAS03 significantly attenuated chemical- and immune checkpoint inhibitor- induced colitis in pre-clinical models. In conclusion, ITNPs show great promise for delivering UroA or its analogues while enhancing therapeutic efficacy at lower doses and reduced frequency compared to free drug administration. This targeted approach offers a potential solution to enhance IBD treatment while minimizing systemic side effects.

Cell Membrane-Coated Nanotherapeutics for the Targeted Treatment of Acute and Chronic Colitis

Integrin α4β1 and α4β7 are overexpressed in macrophages and leukocytes and play important roles in mediating cell homing and recruitment to inflammatory tissues. Herein, to enhance the targeting ability of nanotherapeutics for inflammatory bowel disease (IBD) treatment, cyclosporine A-loaded nanoparticles (CsA NPs) were coated with macrophage membranes (MM-CsA NPs) or leukocyte membranes (LM-CsA NPs). In vitro experiments demonstrated that the physicochemical properties of the nanotherapeutics (e.g., size, zeta potential, polymer dispersity index, and drug release profiles) did not obviously change after cell membrane coating. However, integrin α4β1 and α4β7 were expressed in MM-CsA NPs and LM-CsA NPs, respectively, which significantly inhibited normal macrophage phagocytosis and obviously increased uptake by proinflammatory macrophages and endothelial cells. In vivo experiments verified that cell membrane-coated nanotherapeutics have longer retention times in inflammatory intestinal tissues. Importantly, LM-CsA NPs significantly mitigated weight loss, alleviated colon shortening, decreased disease activity indices (DAIs), and promoted colon tissue repair in acute and chronic colitis model mice. Furthermore, LM-CsA NPs significantly decreased the expression of inflammatory factors such as TNF-α and IL-6 and increased the expression of gut barrier-related proteins such as E-cadherin, ZO-1, and occludin protein in colitis mice.

N-palmitoyl-d-glucosamine limits mucosal damage and VEGF-mediated angiogenesis by PPARα-dependent suppression of pAkt/mTOR/HIF1α pathway and increase in PEA levels in AOM/DSS colorectal carcinoma in mice

Chronic intestinal inflammation and neo-angiogenesis are interconnected in colorectal carcinoma (CRC) pathogenesis. Molecules reducing inflammation and angiogenesis hold promise for CRC prevention and treatment. N-Palmitoyl-d-glucosamine (PGA), a natural glycolipid analog with anti-inflammatory properties, has shown efficacy against acute colitis. Micronized PGA (mPGA) formulations exhibit superior anti-inflammatory activity. This study investigates the in vivo anti-angiogenic and protective effects of mPGA in a mouse model of colitis-associated CRC induced by azoxymethane/dextran sodium sulfate (AOM/DSS). CRC was induced in C57BL/6J mice using intraperitoneal azoxymethane followed by three cycles of 2.5% dextran sodium sulfate (DSS) in drinking water. Mice were treated with mPGA (30-150 mg/kg) with or without the PPARα inhibitor MK886 (10 mg/kg). At Day 70 post-azoxymethane injection, mice underwent anesthetized endoscopic colon evaluation. Post-mortem analysis of tumorigenesis and angiogenesis was performed using histological, immunohistochemical, and immunoblotting techniques. mPGA improved disease progression and survival rates in a dose- and PPARα-dependent manner in AOM/DSS-exposed mice. It reduced polyp formation, decreased pro-angiogenic CD31, pro-proliferative Ki67, and pro-inflammatory TLR4 expression levels, and inhibited VEGF and MMP-9 secretion by disrupting the pAkt/mTOR/HIF1α pathway. mPGA increased colon PEA levels, restoring anti-tumoral PPARα and wtp53 protein expression. Given its lack of toxicity, mPGA shows potential as a nutritional intervention to counteract inflammation-related angiogenesis in CRC.

MAD1 upregulation sensitizes to inflammation-mediated tumor formation

Mitotic Arrest Deficient 1 (gene name MAD1L1), an essential component of the mitotic spindle assembly checkpoint, is frequently overexpressed in colon cancer, which correlates with poor disease-free survival. MAD1 upregulation induces two phenotypes associated with tumor promotion in tissue culture cells-low rates of chromosomal instability (CIN) and destabilization of the tumor suppressor p53. Using CRISPR/Cas9 gene editing, we generated a novel mouse model by inserting a doxycycline (dox)-inducible promoter and HA tag into the endogenous mouse Mad1l1 gene, enabling inducible expression of HA-MAD1 following exposure to dox in the presence of the reverse tet transactivator (rtTA). A modest 2-fold overexpression of MAD1 in murine colon resulted in decreased p53 expression and increased mitotic defects consistent with CIN. After exposure to the colon-specific inflammatory agent dextran sulfate sodium (DSS), 31% of mice developed colon lesions, including a mucinous adenocarcinoma, while none formed in control animals. Lesion incidence was particularly high in male mice, 57% of which developed at least one hyperplastic polyp, adenoma or adenocarcinoma in the colon. Notably, mice expressing HA-MAD1 also developed lesions in tissues in which DSS is not expected to induce inflammation. These findings demonstrate that MAD1 upregulation is sufficient to promote colon tumorigenesis in the context of inflammation in immune-competent mice.

Alzheimer's disease-related presenilins are key to intestinal epithelial cell function and gut immune homoeostasis

OBJECTIVE

Mutations in presenilin genes are the major cause of Alzheimer's disease. However, little is known about their expression and function in the gut. In this study, we identify the presenilins Psen1 and Psen2 as key molecules that maintain intestinal homoeostasis.

DESIGN

Human inflammatory bowel disease (IBD) and control samples were analysed for Psen1 expression. Newly generated intestinal epithelium-specific Psen1-deficient, Psen2-deficient and inducible Psen1/Psen2 double-deficient mice were used to dissect the functional role of presenilins in intestinal homoeostasis.

RESULTS

Psen1 expression was regulated in experimental gut inflammation and in patients with IBD. Induced deletion of Psen1 and Psen2 in mice caused rapid weight loss and spontaneous development of intestinal inflammation. Mice exhibited epithelial barrier disruption with bacterial translocation and deregulation of key pathways for nutrient uptake. Wasting disease was independent of gut inflammation and dysbiosis, as depletion of microbiota rescued Psen-deficient animals from spontaneous colitis development but not from weight loss. On a molecular level, intestinal epithelial cells lacking Psen showed impaired Notch signalling and dysregulated epithelial differentiation.

CONCLUSION

Overall, our study provides evidence that Psen1 and Psen2 are important guardians of intestinal homoeostasis and future targets for barrier-promoting therapeutic strategies in IBD.

An in situ bioadhesive foam as a large intestinal delivery platform for antibody fragment to treat inflammatory bowel disease

Biologics have been widely used as injectables in the treatment of inflammatory bowel disease (IBD). Different local treatment attempts have been developed in recent years. However, maintaining systemic levels of biologics is still crucial for achieving colitis remission. An equilibrium between systemic and local concentrations of biologics is therefore essential for treatment of colitis. Current formulations struggle to create optimal balance between drug concentrations in plasma and the colonic wall. Addressing this challenge, we developed a rectally delivered in situ foam that generates CO2via a reaction between potassium bicarbonate (PB) and citric acid (CA) without the aid of an external device. An anti-TNF-α antibody fragment (Fab) was loaded into the foam formulation, which promoted prolonged colon retention and improved Fab distribution up to proximal colon following rectal administration to mice. In addition, we observed increased plasma Fab concentrations in mice receiving the rectal Fab foam compared to a Fab solution. In a non-everted rat gut ex vivo model, a single exposure to the CO2-containing foam improved macromolecule transepithelial flux across colonic tissue by over ten-fold. Foam efficacy for Fab was investigated in a range of colitis mouse models, from acute to chronic. This non-invasive formulation platform demonstrates potential to overcome existing limitations in delivering biologics to inflamed colonic tissue.

Impact of Nanoplastic Particles on Macrophage Inflammation and Intestinal Health in a Mouse Model of Inflammatory Bowel Disease

BACKGROUND

The increasing presence of plastics in the human diet is raising public concern about the potential risks posed by nanoplastic (NP) particles, which can emerge from the degradation of plastic debris. NP ingestion poses particular risks to individuals with inflammatory bowel disease (IBD), as compromised epithelial barriers may facilitate NP translocation.

METHODS

In vitro, bone-marrow-derived macrophages (BMDMs) were exposed to 25 nm polymethacrylate (PMMA) or 50 nm polystyrene (PS) particles to assess morphological changes and alterations in pro- and anti-inflammatory gene expression. In vivo, mice received PMMA NP particles for 6 months before acute dextran sodium sulfate (DSS) colitis was induced to investigate NP impacts on intestinal health and inflammation.

RESULTS

PMMA and PS NP exposure in BMDMs induced morphological changes indicative of a proinflammatory phenotype characterized by enlarged amoeboid cell shapes. It also triggered an inflammatory response, indicated by increased expression of proinflammatory cytokines such as Tnfa and Il6. Unexpectedly, long-term PMMA NP administration did not affect the intestinal epithelial barrier or exacerbate acute DSS-induced colitis in mice. Colonoscopy and histological analysis revealed no NP-related changes, suggesting adverse effects on intestinal health or inflammation.

CONCLUSION

Our findings from animal models offer some reassurance to IBD patients regarding the effects of NP ingestion. However, variations in lifestyle and dietary habits may lead to significantly higher plastic intake in certain individuals, raising concerns about potential long-term gastrointestinal effects of lifelong plastic consumption.

Miao sour soup alleviates DSS-induced colitis in mice: modulation of gut microbiota and intestinal barrier function

Miao sour soup (MSS), a daily fermented food in Guizhou, China, is rich in microorganisms with various beneficial activities, including anti-inflammatory and antioxidant activities. However, the therapeutic effects of MSS on IBD remain unexplored. This study aimed to investigate the protective effect of MSS against colitis in mice. In this study, we examined the microbial community structure of MSS by metagenomic sequencing and also explored the protective effect of MSS on DSS-induced colitis in mice. We investigated the effects of MSS on intestinal inflammatory response and intestinal barrier function in mice. Finally, the changes in intestinal flora were analyzed based on the 16S rRNA gene sequencing results. Significantly, the experiment result shows that MSS ameliorated the severity of DSS-induced disease in mice by mitigating colitis-associated weight loss, reducing the disease activity index of IBD, alleviating colonic hemorrhagic lesions, increasing colon length, and improving colonic tissue damage. Moreover, MSS preserved intestinal barrier integrity and restored intestinal epithelial function in mice. Additionally, MSS modulated the structure and composition of the intestinal flora. Furthermore, MSS downregulated pro-inflammatory factors and attenuated the NF-κB p65 expression, thereby mitigating the inflammatory response. These findings highlight the protective effect of MSS against DSS-induced colitis, providing substantial scientific support for potential applications of MSS as a functional food.

ZEB1-mediated fibroblast polarization controls inflammation and sensitivity to immunotherapy in colorectal cancer

The EMT-transcription factor ZEB1 is heterogeneously expressed in tumor cells and in cancer-associated fibroblasts (CAFs) in colorectal cancer (CRC). While ZEB1 in tumor cells regulates metastasis and therapy resistance, its role in CAFs is largely unknown. Combining fibroblast-specific Zeb1 deletion with immunocompetent mouse models of CRC, we observe that inflammation-driven tumorigenesis is accelerated, whereas invasion and metastasis in sporadic cancers are reduced. Single-cell transcriptomics, histological characterization, and in vitro modeling reveal a crucial role of ZEB1 in CAF polarization, promoting myofibroblastic features by restricting inflammatory activation. Zeb1 deficiency impairs collagen deposition and CAF barrier function but increases NFκB-mediated cytokine production, jointly promoting lymphocyte recruitment and immune checkpoint activation. Strikingly, the Zeb1-deficient CAF repertoire sensitizes to immune checkpoint inhibition, offering a therapeutic opportunity of targeting ZEB1 in CAFs and its usage as a prognostic biomarker. Collectively, we demonstrate that ZEB1-dependent plasticity of CAFs suppresses anti-tumor immunity and promotes metastasis.

Integrated Metabolomics and Proteomics of Symptomatic and Early Presymptomatic States of Colitis

Colitis has a multifactorial pathogenesis with a strong cross-talk among microbiota, hypoxia, and tissue metabolism. Here, we aimed to characterize the molecular signature of the disease in symptomatic and presymptomatic stages of the inflammatory process at the tissue and fecal level. The study is based on two different murine models for colitis, and HR-MAS NMR on "intact" colon tissues and LC-MS/MS on colon tissue extracts were used to derive untargeted metabolomics and proteomics information, respectively. Solution NMR was used to derive metabolomic profiles of the fecal extracts. By combining metabolomic and proteomic analyses of the tissues, we found increased anaerobic glycolysis, accompanied by an altered citric acid cycle and oxidative phosphorylation in inflamed colons; these changes associate with inflammation-induced hypoxia taking place in colon tissues. Different colitis states were also characterized by significantly different metabolomic profiles of fecal extracts, attributable to both the dysbiosis characteristic of colitis as well as the dysregulated tissue metabolism. Strong and distinctive tissue and fecal metabolomic signatures can be detected before the onset of symptoms. Therefore, untargeted metabolomics of tissues and fecal extracts provides a comprehensive picture of the changes accompanying the disease onset already at preclinical stages, highlighting the diagnostic potential of global metabolomics for inflammatory diseases.

A protective effect of inflammatory bowel disease on the severity of sclerosing cholangitis

Background

Primary sclerosing cholangitis (PSC) is a chronic liver disease marked by inflammation of the bile ducts and results in the development of strictures and fibrosis. A robust clinical correlation exists between PSC and inflammatory bowel disease (IBD). At present, published data are controversial, and it is yet unclear whether IBD drives or attenuates PSC.

Methods

Mdr2-deficient mice or DDC-fed mice were used as experimental models for sclerosing cholangitis. Additionally, colitis was induced in mice with experimental sclerosing cholangitis, either through infection with Citrobacter rodentium or by feeding with DSS. Lastly, fibrosis levels were determined through FibroScan analysis in people with PSC and PSC-IBD.

Results

Using two distinct experimental models of colitis and two models of sclerosing cholangitis, we found that colitis does not aggravate liver pathology, but rather reduces liver inflammation and liver fibrosis. Likewise, people with PSC-IBD have decreased liver fibrosis compared to those with PSC alone.

Conclusions

We found evidence that intestinal inflammation attenuates liver pathology. This study serves as a basis for further research on the pathogenesis of PSC and PSC-IBD, as well as the molecular mechanism responsible for the protective effect of IBD on PSC development. This study could lead to the discovery of novel therapeutic targets for PSC.

Enhancement of colorectal cancer therapy through interruption of the HSF1-HSP90 axis by p53 activation or cell cycle inhibition

The stress-associated molecular chaperone system is an actionable target in cancer therapies. It is ubiquitously upregulated in cancer tissues and enables tumorigenicity by stabilizing hundreds of oncoproteins and disturbing the stoichiometry of protein complexes. Most inhibitors target the key component heat-shock protein 90 (HSP90). However, although classical HSP90 inhibitors are highly tumor-selective, they fail in phase 3 clinical oncology trials. These failures are at least partly due to an interference with a negative feedback loop by HSP90 inhibition, known as heat-shock response (HSR): in response to HSP90 inhibition there is compensatory synthesis of stress-inducible chaperones, mediated by the transcription factor heat-shock factor 1 (HSF1). We recently identified that wildtype p53 (p53) actively reduces the HSR by repressing HSF1 via a p21-CDK4/6-MAPK-HSF1 axis. Here we test the hypothesis that in HSP90-based therapies simultaneous p53 activation or direct cell cycle inhibition interrupts the deleterious HSF1-HSR axis and improves the efficiency of HSP90 inhibitors. Indeed, we find that the clinically relevant p53 activator Idasanutlin suppresses the HSF1-HSR activity in HSP90 inhibitor-based therapies. This combination synergistically reduces cell viability and accelerates cell death in p53-proficient colorectal cancer (CRC) cells, murine tumor-derived organoids and patient-derived organoids (PDOs). Mechanistically, upon combination therapy human CRC cells strongly upregulate p53-associated pathways, apoptosis, and inflammatory immune pathways. Likewise, in the chemical AOM/DSS CRC model in mice, dual HSF1-HSP90 inhibition strongly represses tumor growth and remodels immune cell composition, yet displays only minor toxicities in mice and normal mucosa-derived organoids. Importantly, inhibition of the cyclin dependent kinases 4 and 6 (CDK4/6) under HSP90 inhibition phenocopies synergistic repression of the HSR in p53-proficient CRC cells. Even more important, in p53-deficient (mutp53-harboring) CRC cells, an HSP90 inhibition in combination with CDK4/6 inhibitors similarly suppresses the HSF1-HSR system and reduces cancer growth. Likewise, p53-mutated PDOs strongly respond to dual HSF1-HSP90 pathway inhibition and thus, providing a strategy to target CRC independent of the p53 status. In sum, activating p53 (in p53-proficient cancer cells) or inhibiting CDK4/6 (independent of the p53 status) provide new options to improve the clinical outcome of HSP90-based therapies and to enhance colorectal cancer therapy.

Targeted delivery of Fc-fused PD-L1 for effective management of acute and chronic colitis

The PD-1/PD-L1 pathway in mucosal immunity is currently actively explored and considered as a target for inflammatory bowel disease (IBD) treatment. However, systemic PD-L1 administration may cause unpredictable adverse effects due to immunosuppression. Here we show that reactive oxygen species (ROS)-responsive nanoparticles enhance the efficacy and safety of PD-L1 in a mouse colitis model. The nanoparticles control the accumulation and release of PD-L1 fused to Fc (PD-L1-Fc) at inflammatory sites in the colon. The nanotherapeutics shows superiority in alleviating inflammatory symptoms over systemic PD-L1-Fc administration and mitigates the adverse effects of PD-L1-Fc administration. The nanoparticles-formulated PD-L1-Fc affects production of proinflammatory and anti-inflammatory cytokines, attenuates the infiltration of macrophages, neutrophils, and dendritic cells, increases the frequencies of Treg, Th1 and Tfh cells, reshapes the gut microbiota composition; and increases short-chain fatty acid production. In summary, PD-L1-Fc-decorated nanoparticles may provide an effective and safe strategy for the targeted treatment of IBD.

p21 Prevents the Exhaustion of CD4+ T Cells Within the Antitumor Immune Response Against Colorectal Cancer

BACKGROUND & AIMS

T cells are crucial for the antitumor response against colorectal cancer (CRC). T-cell reactivity to CRC is nevertheless limited by T-cell exhaustion. However, molecular mechanisms regulating T-cell exhaustion are only poorly understood.

METHODS

We investigated the functional role of cyclin-dependent kinase 1a (Cdkn1a or p21) in cluster of differentiation (CD) 4+ T cells using murine CRC models. Furthermore, we evaluated the expression of p21 in patients with stage I to IV CRC. In vitro coculture models were used to understand the effector function of p21-deficient CD4+ T cells.

RESULTS

We observed that the activation of cell cycle regulator p21 is crucial for CD4+ T-cell cytotoxic function and that p21 deficiency in type 1 helper T cells (Th1) leads to increased tumor growth in murine CRC. Similarly, low p21 expression in CD4+ T cells infiltrated into tumors of CRC patients is associated with reduced cancer-related survival. In mouse models of CRC, p21-deficient Th1 cells show signs of exhaustion, where an accumulation of effector/effector memory T cells and CD27/CD28 loss are predominant. Immune reconstitution of tumor-bearing Rag1-/- mice using ex vivo-treated p21-deficient T cells with palbociclib, an inhibitor of cyclin-dependent kinase 4/6, restored cytotoxic function and prevented exhaustion of p21-deficient CD4+ T cells as a possible concept for future immunotherapy of human disease.

CONCLUSIONS

Our data reveal the importance of p21 in controlling the cell cycle and preventing exhaustion of Th1 cells. Furthermore, we unveil the therapeutic potential of cyclin-dependent kinase inhibitors such as palbociclib to reduce T-cell exhaustion for future treatment of patients with colorectal cancer.

Stanniocalcin-1 Promotes PARP1-Dependent Cell Death via JNK Activation in Colitis

Stanniocalcin-1 (STC1) is upregulated by inflammation and modulates oxidative stress-induced cell death. Herein, the function of STC1 in colitis and stress-induced parthanatos, a newly identified type of programmed necrotic cell death dependent on the activation of poly-ADP ribose polymerase-1 (PARP1) is investigated. Results show that STC1 expression is markedly increased in the inflamed colonic mucosa of Crohn's disease (CD) patients and chemically-induced mice colitis models. Evaluation of parthanatos severity and pro-inflammatory cytokine expression shows that intestinal-specific Stc1 knockout (Stc1INT-KO ) mice are resistant to dextran sulfate sodium (DSS)-induced colitis and exhibit lower disease severity. STC1-overexpressing cells show an increased degree of parthanatos and proinflammatory cytokine expression, whereas STC1-knockout cells show a decreased degree of parthanatos. Co-immunoprecipitation, mass spectrometry, and proteomic analyses indicate that STC1 interacts with PARP1, which activates the JNK pathway via PARP1-JNK interactions. Moreover, inhibition of PARP1 and JNK alleviates parthanatos and inflammatory injuries triggered by STC1 overexpression. Finally, following restoration of Stc1 and Parp1 expression by adeno-associated viruses, and overexpression of Stc1 and Parp1 aggravated DSS-induced colitis in Stc1INT-KO mice. In conclusion, STC1 mediates oxidative stress-associated parthanatos and aggravates inflammation via the STC1-PARP1-JNK interactions and subsequent JNK pathway activation in CD pathogenesis.

Nmes1 is a novel regulator of mucosal response influencing intestinal healing potential

The initiation of tissue remodeling following damage is a critical step in preventing the development of immune-mediated diseases. Several factors contribute to mucosal healing, leading to innovative therapeutic approaches for managing intestinal disorders. However, uncovering alternative targets and gaining mechanistic insights are imperative to enhance therapy efficacy and broaden its applicability across different intestinal diseases. Here we demonstrate that Nmes1, encoding for Normal Mucosa of Esophagus-Specific gene 1, also known as Aa467197, is a novel regulator of mucosal healing. Nmes1 influences the macrophage response to the tissue remodeling cytokine IL-4 in vitro. In addition, using two murine models of intestinal damage, each characterized by a type 2-dominated environment with contrasting functions, the ablation of Nmes1 results in decreased intestinal regeneration during the recovery phase of colitis, while enhancing parasitic egg clearance and reducing fibrosis during the advanced stages of Schistosoma mansoni infection. These outcomes are associated with alterations in CX3CR1+ macrophages, cells known for their wound-healing potential in the inflamed colon, hence promising candidates for cell therapies. All in all, our data indicate Nmes1 as a novel contributor to mucosal healing, setting the basis for further investigation into its potential as a new target for the treatment of colon-associated inflammation.

A nanoparticle platform for combined mucosal healing and immunomodulation in inflammatory bowel disease treatment

Current treatments for inflammatory bowel disease (IBD) treatment consist of anti-inflammatory products. In this study, we sought to induce the physiological secretion of glucagon-like peptide 2, a peptide with intestinal growth-promoting activity, via nanoparticles while simultaneously providing with immunomodulation by tailoring the nanoparticle surface. To this end, we developed hybrid lipid hyaluronate-KPV conjugated nanoparticles loaded with teduglutide for combination therapy in IBD. The nanocarriers induced (or did not induce) immunosuppression depending on the presence (or absence) of a hyaluronan-KPV functionalization. This strategy holds promise as a nanoparticle platform for combined mucosal healing and immunomodulation in IBD treatment.

Engineering tumor-colonizing E. coli Nissle 1917 for detection and treatment of colorectal neoplasia

Bioengineered probiotics enable new opportunities to improve colorectal cancer (CRC) screening, prevention and treatment. Here, first, we demonstrate selective colonization of colorectal adenomas after oral delivery of probiotic E. coli Nissle 1917 (EcN) to a genetically-engineered murine model of CRC predisposition and orthotopic models of CRC. We next undertake an interventional, double-blind, dual-centre, prospective clinical trial, in which CRC patients take either placebo or EcN for two weeks prior to resection of neoplastic and adjacent normal colorectal tissue (ACTRN12619000210178). We detect enrichment of EcN in tumor samples over normal tissue from probiotic-treated patients (primary outcome of the trial). Next, we develop early CRC intervention strategies. To detect lesions, we engineer EcN to produce a small molecule, salicylate. Oral delivery of this strain results in increased levels of salicylate in the urine of adenoma-bearing mice, in comparison to healthy controls. To assess therapeutic potential, we engineer EcN to locally release a cytokine, GM-CSF, and blocking nanobodies against PD-L1 and CTLA-4 at the neoplastic site, and demonstrate that oral delivery of this strain reduces adenoma burden by ~50%. Together, these results support the use of EcN as an orally-deliverable platform to detect disease and treat CRC through the production of screening and therapeutic molecules.

Gut microbiota metabolite indole-3-acetic acid maintains intestinal epithelial homeostasis through mucin sulfation

The global incidence and prevalence of inflammatory bowel disease (IBD) are gradually increasing. A high-fat diet (HFD) is known to disrupt intestinal homeostasis and aggravate IBD, yet the underlying mechanisms remain largely undefined. Here, a positive correlation between dietary fat intake and disease severity in both IBD patients and murine colitis models is observed. A HFD induces a significant decrease in indole-3-acetic acid (IAA) and leads to intestinal barrier damage. Furthermore, IAA supplementation enhances intestinal mucin sulfation and effectively alleviates colitis. Mechanistically, IAA upregulates key molecules involved in mucin sulfation, including 3'-phosphoadenosine 5'-phosphosulfate synthase 2 (Papss2) and solute carrier family 35 member B3 (Slc35b3), the synthesis enzyme and the transferase of 3'-phosphoadenosine-5'-phosphosulfate (PAPS), via the aryl hydrocarbon receptor (AHR). More importantly, AHR can directly bind to the transcription start site of Papss2. Oral administration of Lactobacillus reuteri, which can produce IAA, contributes to protecting against colitis and promoting mucin sulfation, while the modified L. reuteri strain lacking the iaaM gene (LactobacillusΔiaaM) and the ability to produce IAA fail to exhibit such effects. Overall, IAA enhances intestinal mucin sulfation through the AHR-Papss2-Slc35b3 pathway, contributing to the protection of intestinal homfeostasis.

Porphyromonas gingivalis fuels colorectal cancer through CHI3L1-mediated iNKT cell-driven immune evasion

The interaction between the gut microbiota and invariant Natural Killer T (iNKT) cells plays a pivotal role in colorectal cancer (CRC). The pathobiont Fusobacterium nucleatum influences the anti-tumor functions of CRC-infiltrating iNKT cells. However, the impact of other bacteria associated with CRC, like Porphyromonas gingivalis, on their activation status remains unexplored. In this study, we demonstrate that mucosa-associated P. gingivalis induces a protumour phenotype in iNKT cells, subsequently influencing the composition of mononuclear-phagocyte cells within the tumor microenvironment. Mechanistically, in vivo and in vitro experiments showed that P. gingivalis reduces the cytotoxic functions of iNKT cells, hampering the iNKT cell lytic machinery through increased expression of chitinase 3-like-1 protein (CHI3L1). Neutralization of CHI3L1 effectively restores iNKT cell cytotoxic functions suggesting a therapeutic potential to reactivate iNKT cell-mediated antitumour immunity. In conclusion, our data demonstrate how P. gingivalis accelerates CRC progression by inducing the upregulation of CHI3L1 in iNKT cells, thus impairing their cytotoxic functions and promoting host tumor immune evasion.

Intrarectal Administration of Adelmidrol plus Hyaluronic Acid Gel Ameliorates Experimental Colitis in Mice and Inhibits Pro-Inflammatory Response in Ex Vivo Cultured Biopsies Derived from Ulcerative Colitis-Affected Patients

Improving clinical outcomes and delaying disease recrudescence in Ulcerative Colitis (UC) patients is crucial for clinicians. In addition to traditional and new pharmacological therapies that utilize biological drugs, the development of medical devices that can ameliorate UC and facilitate the remission phase should not be overlooked. Drug-based therapy requires time to be personalized and to evaluate the benefit/risk ratio. However, the increasing number of diagnosed UC cases worldwide necessitates the exploration of new strategies to enhance clinical outcomes. By incorporating medical devices alongside pharmacological treatments, clinicians can provide additional support to UC patients, potentially improving their condition and slowing down the recurrence of symptoms. Chemically identified as an azelaic acid derivative and palmitoylethanolamide (PEA) analog, adelmidrol is a potent anti-inflammatory and antioxidant compound. In this study, we aimed to evaluate the effect of an intrarectal administration of 2% adelmidrol (Ade) and 0.1% hyaluronic acid (HA) gel formulation in both the acute and resolution phase of a mouse model of colitis induced via DNBS enema. We also investigated its activity in cultured human colon biopsies isolated from UC patients in the remission phase at follow-up when exposed in vitro to a cytomix challenge. Simultaneously, with its capacity to effectively alleviate chronic painful inflammatory cystitis when administered intravesically to urological patients such as Vessilen, the intrarectal administration of Ade/HA gel has shown remarkable potential in improving the course of colitis. This treatment approach has demonstrated a reduction in the histological damage score and an increase in the expression of ZO-1 and occludin tight junctions in both in vivo studies and human specimens. By acting independently on endogenous PEA levels and without any noticeable systemic absorption, the effectiveness of Ade/HA gel is reliant on a local antioxidant mechanism that functions as a "barrier effect" in the inflamed gut. Building on the findings of this preliminary study, we are confident that the Ade/HA gel medical device holds promise as a valuable adjunct in supporting traditional anti-UC therapies.

Macrophage polarization toward M1 phenotype in T cell transfer colitis model

BACKGROUND

T cell transfer colitis model is often used to study the CD4+ T cell functions in the intestine. However, the specific roles of macrophages in colitis remain unclear. In this study, we aimed to evaluate the phenotype and functions of macrophages in the colonic lamina propria (LP) in a colitis model.

METHODS

Colitis was induced in scid mice via the adaptive transfer of CD4+CD45RBhi T cells. Then, flow cytometry was used to determine the number of macrophages in the colonic LP and expression of cytokines in macrophages at the onset of colitis. Moreover, M1/M2 macrophage markers were detected in the colonic LP during colitis development using high-dimensional single-cell data and gating-based analyses. Expression levels of M1 markers in macrophages isolated from the colonic LP were measured using quantitative reverse transcription-polymerase chain reaction. Additionally, macrophages were co-cultured with T cells isolated from the colon to assess colitogenic T cell activation.

RESULTS

Infiltration of macrophages into the colon increased with the development of colitis in the T cell transfer colitis model. M1/M2 macrophage markers were observed in this model, as observed in the colon of patients with inflammatory bowel disease (IBD). Moreover, number of M1 macrophages increased, whereas that of M2 macrophages decreased in the colonic LP during colitis development. M1 macrophages were identified as the main source of inflammatory cytokine production, and colitogenic T cells were activated via interactions with these macrophages.

CONCLUSIONS

Our findings revealed that macrophages polarized toward the M1 phenotype in LP during colitis development in the T cell transfer colitis model. Therefore, the colitis model is suitable for the evaluation of the efficacy of macrophage-targeted drugs in human IBD treatment. Furthermore, this model can be used to elucidate the in vivo functions of macrophages in the colon of patients with IBD.

Discovery and Optimization of Novel hDHODH Inhibitors for the Treatment of Inflammatory Bowel Disease

As a key rate-limiting enzyme in the de novo synthesis of pyrimidine nucleotides, human dihydroorotate dehydrogenase (hDHODH) is considered a known target for the treatment of autoimmune diseases, including inflammatory bowel disease (IBD). Herein, BAY 41-2272 with a 1H-pyrazolo[3,4-b]pyridine scaffold was identified as an hDHODH inhibitor by screening an active compound library containing 5091 molecules. Further optimization led to 2-(1-(2-chloro-6-fluorobenzyl)-1H-pyrrolo[2,3-b]pyridin-3-yl)-5-cyclopropylpyrimidin-4-amine (w2), which was found to be the most promising and drug-like compound with potent inhibitory activity against hDHODH (IC50 = 173.4 nM). Compound w2 demonstrated acceptable pharmacokinetic characteristics and alleviated the severity of acute ulcerative colitis induced by dextran sulfate sodium in a dose-dependent manner. Notably, w2 exerted better therapeutic effects on ulcerative colitis than hDHODH inhibitor vidofludimus and Janus kinase (JAK) inhibitor tofacitinib. Taken together, w2 is a promising hDHODH inhibitor for the treatment of IBD and deserves to be developed as a preclinical candidate.

Hematopoietic-specific heterozygous loss of Dnmt3a exacerbates colitis-associated colon cancer

Clonal hematopoiesis (CH) is defined as clonal expansion of mutant hematopoietic stem cells absent diagnosis of a hematologic malignancy. Presence of CH in solid tumor patients, including colon cancer, correlates with shorter survival. We hypothesized that bone marrow-derived cells with heterozygous loss-of-function mutations of DNMT3A, the most common genetic alteration in CH, contribute to the pathogenesis of colon cancer. In a mouse model that combines colitis-associated colon cancer (CAC) with experimental CH driven by Dnmt3a+/Δ, we found higher tumor penetrance and increased tumor burden compared with controls. Histopathological analysis revealed accentuated colonic epithelium injury, dysplasia, and adenocarcinoma formation. Transcriptome profiling of colon tumors identified enrichment of gene signatures associated with carcinogenesis, including angiogenesis. Treatment with the angiogenesis inhibitor axitinib eliminated the colon tumor-promoting effect of experimental CH driven by Dnmt3a haploinsufficiency and rebalanced hematopoiesis. This study provides conceptually novel insights into non-tumor-cell-autonomous effects of hematopoietic alterations on colon carcinogenesis and identifies potential therapeutic strategies.

Spermidine Ameliorates Colitis via Induction of Anti-Inflammatory Macrophages and Prevention of Intestinal Dysbiosis

BACKGROUND AND AIMS

Exacerbated immune activation, intestinal dysbiosis and a disrupted intestinal barrier are common features among inflammatory bowel disease [IBD] patients. The polyamine spermidine, which is naturally present in all living organisms, is an integral component of the human diet, and exerts beneficial effects in human diseases. Here, we investigated whether spermidine treatment ameliorates intestinal inflammation and offers therapeutic potential for IBD treatment.

METHODS

We assessed the effect of oral spermidine administration on colitis severity in the T cell transfer colitis model in Rag2-/- mice by endoscopy, histology and analysis of markers of molecular inflammation. The effects on the intestinal microbiome were determined by 16S rDNA sequencing of mouse faeces. The impact on intestinal barrier integrity was evaluated in co-cultures of patient-derived macrophages with intestinal epithelial cells.

RESULTS

Spermidine administration protected mice from intestinal inflammation in a dose-dependent manner. While T helper cell subsets remained unaffected, spermidine promoted anti-inflammatory macrophages and prevented the microbiome shift from Firmicutes and Bacteroides to Proteobacteria, maintaining a healthy gut microbiome. Consistent with spermidine as a potent activator of the anti-inflammatory molecule protein tyrosine phosphatase non-receptor type 2 [PTPN2], its colitis-protective effect was dependent on PTPN2 in intestinal epithelial cells and in myeloid cells. The loss of PTPN2 in epithelial and myeloid cells, but not in T cells, abrogated the barrier-protective, anti-inflammatory effect of spermidine and prevented the anti-inflammatory polarization of macrophages.

CONCLUSION

Spermidine reduces intestinal inflammation by promoting anti-inflammatory macrophages, maintaining a healthy microbiome and preserving epithelial barrier integrity in a PTPN2-dependent manner.

TCF-1 limits intraepithelial lymphocyte antitumor immunity in colorectal carcinoma

Intraepithelial lymphocytes (IELs), including αβ and γδ T cells (T-IELs), constantly survey and play a critical role in maintaining the gastrointestinal epithelium. We show that cytotoxic molecules important for defense against cancer were highly expressed by T-IELs in the small intestine. In contrast, abundance of colonic T-IELs was dependent on the microbiome and displayed higher expression of TCF-1/TCF7 and a reduced effector and cytotoxic profile, including low expression of granzymes. Targeted deletion of TCF-1 in γδ T-IELs induced a distinct effector profile and reduced colon tumor formation in mice. In addition, TCF-1 expression was significantly reduced in γδ T-IELs present in human colorectal cancers (CRCs) compared with normal healthy colon, which strongly correlated with an enhanced γδ T-IEL effector phenotype and improved patient survival. Our work identifies TCF-1 as a colon-specific T-IEL transcriptional regulator that could inform new immunotherapy strategies to treat CRC.

Cyclosporine A-Encapsulated pH/ROS Dual-Responsive Nanoformulations for the Targeted Treatment of Colitis in Mice

Inflammatory bowel disease (IBD) is a frequently occurring disease that seriously influences the patient's quality of life. To decrease adverse effects and improve efficacy of therapeutics, nanomedicines have been widely used to treat IBD. However, how to thoroughly release payloads under an inflammatory microenvironment and synergistic therapy of IBD need to be further investigated. To address this issue, cyclosporine A (CsA)-loaded, folic acid (FA)-modified, pH and reactive oxygen species (ROS) dual-responsive nanoparticles (FA-CsA NPs) were fabricated using pH/ROS-responsive material as carrier. The prepared FA-CsA NPs had spherical shape and uniform size distribution and could smartly release their payloads under acid and/or ROS microenvironment. In vitro experiments demonstrated that FA-CsA NPs can be effectively internalized by activated macrophages, and the internalized NPs could down-regulate the expression of proinflammatory cytokines compared to free drug or nontargeted NPs. In vivo experiments verified that FA-CsA NPs significantly accumulated at inflammatory colon tissues and the accumulated NPs obviously improved the symptoms of colitis in mice without obvious adverse effects. In conclusion, our results provided a candidate for the targeted treatment of IBD.

Evaluation of the effect of tramadol, paracetamol and metamizole on the severity of experimental colitis

Application of dextran sodium sulfate (DSS) is often used to induce experimental colitis. Current state of the art is to refrain from the use of analgesics due to their possible interaction with the model. However, the use of analgesics would be beneficial to reduce the overall constraint imposed on the animals. Here, we analyzed the effect of the analgesics Dafalgan (paracetamol), Tramal (tramadol) and Novalgin (metamizole) on DSS-induced colitis. To study the effect of those analgesics in colitis mouse models, acute and chronic colitis was induced in female C57BL6 mice by DSS administration in the drinking water. Analgesics were added to the drinking water on days four to seven (acute colitis) or on days six to nine of each DSS cycle (chronic colitis). Tramadol and paracetamol had minor effects on colitis severity. Tramadol reduced water uptake and activity levels slightly, while mice receiving paracetamol presented with a better overall appearance. Metamizole, however, significantly reduced water uptake, resulting in pronounced weight loss. In conclusion, our experiments show that tramadol and paracetamol are viable options for the use in DSS-induced colitis models. However, paracetamol seems to be slightly more favorable since it promoted the overall wellbeing of the animals upon DSS administration without interfering with typical readouts of colitis severity.

Administration of intestinal mesenchymal stromal cells reduces colitis-associated cancer in C57BL/6J mice modulating the immune response and gut dysbiosis

BACKGROUND

Patients with inflammatory bowel disease (IBD) have a higher risk of developing colitis-associated colorectal cancer (CAC) with poor prognosis. IBD etiology remains undefined but involves environmental factors, genetic predisposition, microbiota imbalance (dysbiosis) and mucosal immune defects. Mesenchymal stromal cell (MSC) injections have shown good efficacy in reducing intestinal inflammation in animal and human studies. However, their effect on tumor growth in CAC and their capacity to restore gut dysbiosis are not clear.

METHODS

The outcome of systemic administrations of in vitro expanded human intestinal MSCs (iMSCs) on tumor growth in vivo was evaluated using the AOM/DSS model of CAC in C57BL/6J mice. Innate and adaptive immune responses in blood, mesenteric lymph nodes (MLNs) and colonic tissue were analyzed by flow cytometry. Intestinal microbiota composition was evaluated by 16S rRNA amplicon sequencing.

RESULTS

iMSCs significantly inhibited colitis and intestinal tumor development, reducing IL-6 and COX-2 expression, and IL-6/STAT3 and PI3K/Akt signaling. iMSCs decreased colonic immune cell infiltration, and partly restored intestinal monocyte homing and differentiation. iMSC administration increased the numbers of Tregs and IFN-γ+CD8+ T cells in the MLNs while decreasing the IL-4+Th2 response. It also ameliorated intestinal dysbiosis in CAC mice, increasing diversity and Bacillota/Bacteroidota ratio, as well as Akkermansia abundance, while reducing Alistipes and Turicibacter, genera associated with inflammation.

CONCLUSION

Administration of iMSCs protects against CAC, ameliorating colitis and partially reverting intestinal dysbiosis, supporting the use of MSCs for the treatment of IBD.

Engineered bacteria detect tumor DNA

Synthetic biology has developed sophisticated cellular biosensors to detect and respond to human disease. However, biosensors have not yet been engineered to detect specific extracellular DNA sequences and mutations. Here, we engineered naturally competent Acinetobacter baylyi to detect donor DNA from the genomes of colorectal cancer (CRC) cells, organoids, and tumors. We characterized the functionality of the biosensors in vitro with coculture assays and then validated them in vivo with sensor bacteria delivered to mice harboring colorectal tumors. We observed horizontal gene transfer from the tumor to the sensor bacteria in our mouse model of CRC. This cellular assay for targeted, CRISPR-discriminated horizontal gene transfer (CATCH) enables the biodetection of specific cell-free DNA.

Reduced smooth muscle-fibroblasts transformation potentially decreases intestinal wound healing and colitis-associated cancer in ageing mice

Cancer and impaired tissue wound healing with ageing are closely related to the quality of life of the elderly population. Given the increased incidence of cancer and the population ageing trend globally, it is very important to explore how ageing impairs tissue wound healing and spontaneous cancer. In a murine model of DSS-induced acute colitis and AOM/DSS-induced colitis-associated cancer (CAC), we found ageing significantly decreases intestinal wound healing and simultaneous CAC initiation, although ageing does not affect the incidence of AOM-induced, sporadic non-inflammatory CRC. Mechanistically, reduced fibroblasts were observed in the colitis microenvironment of ageing mice. Through conditional lineage tracing, an important source of fibroblasts potentially derived from intestinal smooth muscle cells (ISMCs) was identified orchestrating intestinal wound healing and CAC initiation in young mice. However, the number of transformed fibroblasts from ISMCs significantly decreased in ageing mice, accompanied by decreased intestinal wound healing and decreased CAC initiation. ISMCs-fibroblasts transformation in young mice and reduction of this transformation in ageing mice were also confirmed by ex-vivo intestinal muscular layer culture experiments. We further found that activation of YAP/TAZ in ISMCs is required for the transformation of ISMCs into fibroblasts. Meanwhile, the reduction of YAP/TAZ activation in ISMCs during intestinal wound healing was observed in ageing mice. Conditional knockdown of YAP/TAZ in ISMCs of young mice results in reduced fibroblasts in the colitis microenvironment, decreased intestinal wound healing and decreased CAC initiation, similar to the phenotype of ageing mice. In addition, the data from intestine samples derived from inflammatory bowel disease (IBD) patients show that activation of YAP/TAZ also occurs in ISMCs from these patients. Collectively, our work reveals an important role of the ageing stromal microenvironment in intestinal wound healing and CAC initiation. Furthermore, our work also identified a potential source of fibroblasts involved in colitis and CAC.

Tigecycline reduces tumorigenesis in colorectal cancer via inhibition of cell proliferation and modulation of immune response

BACKGROUND

and Purpose: Colorectal cancer (CRC) is one of the cancers with the highest incidence in which APC gene mutations occur in almost 80% of patients. This mutation leads to β-catenin aberrant accumulation and an uncontrolled proliferation. Apoptosis evasion, changes in the immune response and microbiota composition are also events that arise in CRC. Tetracyclines are drugs with proven antibiotic and immunomodulatory properties that have shown cytotoxic activity against different tumor cell lines.

EXPERIMENTAL APPROACH

The effect of tigecycline was evaluated in vitro in HCT116 cells and in vivo in a colitis-associated colorectal cancer (CAC) murine model. 5-fluorouracil was assayed as positive control in both studies.

KEY RESULTS

Tigecycline showed an antiproliferative activity targeting the Wnt/β-catenin pathway and downregulating STAT3. Moreover, tigecycline induced apoptosis through extrinsic, intrinsic and endoplasmic reticulum pathways converging on an increase of CASP7 levels. Furthermore, tigecycline modulated the immune response in CAC, reducing the cancer-associated inflammation through downregulation of cytokines expression. Additionally, tigecycline favored the cytotoxic activity of cytotoxic T lymphocytes (CTLs), one of the main immune defenses against tumor cells. Lastly, the antibiotic reestablished the gut dysbiosis in CAC mice increasing the abundance of bacterial genera and species, such as Akkermansia and Parabacteroides distasonis, that act as protectors against tumor development. These findings resulted in a reduction of the number of tumors and an amelioration of the tumorigenesis process in CAC.

CONCLUSION AND IMPLICATIONS

Tigecycline exerts a beneficial effect against CRC supporting the use of this antibiotic for the treatment of this disease.

Transrectal Absorber Guide Raster-Scanning Optoacoustic Mesoscopy for Label-Free In Vivo Assessment of Colitis

Optoacoustic imaging (OAI) enables microscale imaging of endogenous chromophores such as hemoglobin at significantly higher penetration depths compared to other optical imaging technologies. Raster-scanning optoacoustic mesoscopy (RSOM) has recently been shown to identify superficial microvascular changes associated with human skin pathologies. In animal models, the imaging depth afforded by RSOM can enable entirely new capabilities for noninvasive imaging of vascular structures in the gastrointestinal tract, but exact localization of intra-abdominal organs is still elusive. Herein the development and application of a novel transrectal absorber guide for RSOM (TAG-RSOM) is presented to enable accurate transabdominal localization and assessment of colonic vascular networks in vivo. The potential of TAG-RSOM is demonstrated through application during mild and severe acute colitis in mice. TAG-RSOM enables visualization of transmural vascular networks, with changes in colon wall thickness, blood volume, and OAI signal intensities corresponding to colitis-associated inflammatory changes. These findings suggest TAG-RSOM can provide a novel monitoring tool in preclinical IBD models, refining animal procedures and underlines the capabilities of such technologies to address inflammatory bowel diseases in humans.

iNKT cell-neutrophil crosstalk promotes colorectal cancer pathogenesis

iNKT cells account for a relevant fraction of effector T-cells in the intestine and are considered an attractive platform for cancer immunotherapy. Although iNKT cells are cytotoxic lymphocytes, their functional role in colorectal cancer (CRC) is still controversial, limiting their therapeutic use. Thus, we examined the immune cell composition and iNKT cell phenotype of CRC lesions in patients (n = 118) and different murine models. High-dimensional single-cell flow-cytometry, metagenomics, and RNA sequencing experiments revealed that iNKT cells are enriched in tumor lesions. The tumor-associated pathobiont Fusobacterium nucleatum induces IL-17 and Granulocyte-macrophage colony-stimulating factor (GM-CSF) expression in iNKT cells without affecting their cytotoxic capability but promoting iNKT-mediated recruitment of neutrophils with polymorphonuclear myeloid-derived suppressor cells-like phenotype and functions. The lack of iNKT cells reduced the tumor burden and recruitment of immune suppressive neutrophils. iNKT cells in-vivo activation with α-galactosylceramide restored their anti-tumor function, suggesting that iNKT cells can be modulated to overcome CRC-associated immune evasion. Tumor co-infiltration by iNKT cells and neutrophils correlates with negative clinical outcomes, highlighting the importance of iNKT cells in the pathophysiology of CRC. Our results reveal a functional plasticity of iNKT cells in CRC, suggesting a pivotal role of iNKT cells in shaping the tumor microenvironment, with relevant implications for treatment.