Gigantol ameliorates DSS-induced colitis via suppressing β2 integrin mediated adhesion and chemotaxis of macrophage

ETHNOPHARMACOLOGICAL RELEVANCE

Dendrobium, recognized as "Shihu" in traditional Chinese medicine, holds a rich history of medicinal utilization documented in the Chinese Pharmacopoeia. Ancient texts like "Shen Nong Ben Cao Jing" extol Dendrobium's virtues as a superior herbal medicine fortifying "Yin" and invigorating the five viscera. Dendrobium is extensively employed for the treatment of gastrointestinal inflammatory disorders, showcasing significant therapeutic efficacy, particularly against ulcerative colitis (UC), within the realm of Chinese ethnopharmacology. Dendrobium plays crucial pharmacological roles due to its rich content of polysaccharides, alkaloids, phenanthrenes, and bibenzyls. Gigantol, a prominent bibenzyl compound, stands out as one of the most vital active constituents within Dendrobium, the gigantol content of Dendrobium leaves can reach approximately 4.79 μg/g. Its significance lies in being recognized as a noteworthy anti-inflammatory compound derived from Dendrobium.

AIM OF THE STUDY

Given the pivotal role of gigantol as a primary active substance in Dendrobium, the therapeutic potential of gigantol for gastrointestinal diseases remains enigmatic. Our present investigation aimed to evaluate the therapeutic effects of gigantol on dextran sulfate sodium (DSS)-induced colitis and reveal its potential mechanism in countering UC activity.

MATERIALS AND METHODS

The protective efficacy of gigantol against colitis was assessed by examining the histopathological changes and conducting biochemical analyses of colon from DSS-challenged mice. Assessments focused on gigantol's impact on improving the intestinal epithelial barrier and its anti-inflammatory effects in colonic tissues of colitis mice. Investigative techniques included the exploration of the macrophage inflammatory signaling pathway via qPCR and Western blot analyses. In vitro studies scrutinized macrophage adhesion, migration, and chemotaxis utilizing transwell and Zigmond chambers. Furthermore, F-actin and Rac1 activation assays detailed cellular cytoskeletal remodeling. The potential therapeutic target of gigantol was identified and validated through protein binding analysis, competitive enzyme-linked immunosorbent assay (ELISA), cellular thermal shift assay (CETSA), and drug affinity responsive target stability (DARTS) assay. The binding sites between gigantol and its target were predicted via molecular docking.

RESULTS

Gigantol ameliorated symptoms of DSS-induced colitis, rectified damage to the intestinal barrier, and suppressed the production of pro-inflammatory cytokines in colonic tissues. Intriguingly, gigantol significantly curtailed NF-κB signaling activation in the colons of DSS-induced colitis mice. Notably, gigantol impaired the β2 integrin-dependent adhesion and migratory capacity of RAW264.7 cells. Moreover, gigantol notably influenced the cytoskeleton remodeling of RAW264.7 cells by suppressing Vav1 phosphorylation and Rac1 activation. Mechanistically, gigantol interacted with β2 integrin, subsequently diminishing binding affinity with intercellular adhesion molecule-1 (ICAM-1).

CONCLUSIONS

In conclusion, these findings elucidate that gigantol ameliorates DSS-induced colitis by antagonizing β2 integrin-mediated macrophage adhesion, migration, and chemotaxis, thus it may impede macrophage recruitment and infiltration into colonic tissues. This study suggests that gigantol shows promise as a viable candidate for clinical colitis therapy.

Clinical Implications of Microscopic Colitis Isolated to Polyps

Microscopic colitis is generally identified on random colon biopsies performed for chronic diarrhea, but rarely incidental polyps have histologic features of microscopic colitis. We compared patients with polypoid microscopic colitis to control patients with conventional polyps to determine the implications of polypoid microscopic colitis.

Medical records were searched for patients without prior or concurrent microscopic colitis who were found to have polypoid microscopic colitis. For each patient with polypoid microscopic colitis, one patient with conventional polyps was selected as a control. We reviewed the histologic features of each polypoid microscopic colitis specimen, and evaluated endoscopic and clinical findings for polypoid microscopic colitis patients and controls.

Twenty-six patients with polypoid microscopic colitis were identified with histologic features of collagenous colitis in 8 patients (31%) and lymphocytic colitis in 18 patients (69%). Polypoid microscopic colitis was unifocal in 14 patients (54%) and multifocal in 12 patients (46%). Patients with polypoid microscopic colitis were older than control patients (median age = 60 years vs 66 years, P = .04). On follow-up 7 patients with polypoid microscopic colitis (33%) developed chronic diarrhea compared to 3 (12%) controls (P = .16). Of patients with follow-up biopsies, 1 patient with polypoid microscopic colitis (13%) and no control patients developed microscopic colitis (P = 1).

Polypoid microscopic colitis may be identified in asymptomatic patients and most patients do not develop chronic diarrhea, but some patients with polypoid microscopic colitis develop diarrhea (33% vs 12% in controls) or conventional microscopic colitis on follow-up. Thus pathologists should distinguish polypoid microscopic colitis from conventional microscopic colitis but may inform clinicians of the uncertain association with chronic diarrhea to guide decisions regarding follow-up.

Resveratrol ameliorates ulcerative colitis by upregulating Nrf2/HO‑1 pathway activity: Integrating animal experiments and network pharmacology

Ulcerative colitis (UC) is a chronic idiopathic inflammatory condition affecting the rectum and colon. Inflammation and compromisation of the intestinal mucosal barrier are key in UC pathogenesis. Resveratrol (Res) is a naturally occurring polyphenol that exhibits anti‑inflammatory and antioxidant properties. Nuclear factor erythroid‑2‑related factor 2/heme oxygenase 1 (Nrf2/HO‑1) pathway regulates occurrence and development of numerous types of diseases through anti‑inflammatory and antioxidant activity. However, it is not clear whether Nrf2/HO‑1 pathway is involved in the treatment of Res in UC. Therefore, the present study aimed to investigate whether Res modulates the Nrf2/HO‑1 signaling pathway to attenuate UC in mice. Dextran sulfate sodium (DSS) was used to induce experimental UC in male C57BL/6J mice. Disease activity index (DAI) and hematoxylin eosin (H&E) staning was used to assessed the magnitude of colonic lesions in UC mice. ELISA) was utilized to quantify inflammatory cytokines (IL‑6, IL‑1β, TNF‑α and IL‑10) in serum and colon tissues. Immunohistochemistry and Western blot were used to evaluate the expression levels of tight junction (TJ) proteins [zonula occludens (ZO)‑1 and Occludin] in colon tissues. Pharmacokinetic (PK) parameters of Res were derived from TCMSP database. Networkpharmacology was employed to identify the biological function and pharmacological mechanism of Res in the process of relieving UC, and the key target was screened. The binding ability of Res and key target was verified by molecular docking. Finally, the effectiveness of key target was substantiated by Western blot. Res decreased DAI, ameliorated histopathological changes such as crypt loss, disappeatance of the mucosal epithelium, and inflammatory infiltration in mice. Additionally, Res decreased expression of pro‑inflammatory cytokines IL‑6, IL‑1β and TNF‑α and increased anti‑inflammatory factor IL‑10 expression. Res also restored the decreased protein expression of ZO‑1 and occludin after DSS treatment, increasing the integrity of the intestinal mucosal barrier. The PK properties of Res suggested that Res possesses the therapeutic potential for oral administration. Network pharmacology revealed that Res alleviated UC through anti‑inflammatory and antioxidant pathways, and confirmed that Nrf2 has a high binding affinity with Res and is a key target of Res against UC. Western blotting demonstrated that Res treatment increased the protein levels of Nrf2 and HO‑1. In conclusion, Res treatment activated the Nrf2/HO‑1 pathway to decrease clinical symptoms, inflammatory responses, and intestinal mucosal barrier damage in experimental UC mice.

Interleukin 21 Drives a Hypermetabolic State and CD4+ T-Cell-Associated Pathogenicity in Chronic Intestinal Inflammation

BACKGROUND & AIMS

Incapacitated regulatory T cells (Tregs) contribute to immune-mediated diseases. Inflammatory Tregs are evident during human inflammatory bowel disease; however, mechanisms driving the development of these cells and their function are not well understood. Therefore, we investigated the role of cellular metabolism in Tregs relevant to gut homeostasis.

METHODS

Using human Tregs, we performed mitochondrial ultrastructural studies via electron microscopy and confocal imaging, biochemical and protein analyses using proximity ligation assay, immunoblotting, mass cytometry and fluorescence-activated cell sorting, metabolomics, gene expression analysis, and real-time metabolic profiling utilizing the Seahorse XF analyzer. We used a Crohn's disease single-cell RNA sequencing dataset to infer the therapeutic relevance of targeting metabolic pathways in inflammatory Tregs. We examined the superior functionality of genetically modified Tregs in CD4+ T-cell-induced murine colitis models.

RESULTS

Mitochondria-endoplasmic reticulum appositions, known to mediate pyruvate entry into mitochondria via voltage-dependent anion channel 1 (VDAC1), are abundant in Tregs. VDAC1 inhibition perturbed pyruvate metabolism, eliciting sensitization to other inflammatory signals reversible by membrane-permeable methyl pyruvate supplementation. Notably, interleukin (IL) 21 diminished mitochondria-endoplasmic reticulum appositions, resulting in enhanced enzymatic function of glycogen synthase kinase 3 β, a putative negative regulator of VDAC1, and a hypermetabolic state that amplified Treg inflammatory response. Methyl pyruvate and glycogen synthase kinase 3 β pharmacologic inhibitor (LY2090314) reversed IL21-induced metabolic rewiring and inflammatory state. Moreover, IL21-induced metabolic genes in Tregs in vitro were enriched in human Crohn's disease intestinal Tregs. Adoptively transferred Il21r-/- Tregs efficiently rescued murine colitis in contrast to wild-type Tregs.

CONCLUSIONS

IL21 triggers metabolic dysfunction associated with Treg inflammatory response. Inhibiting IL21-induced metabolism in Tregs may mitigate CD4+ T-cell-driven chronic intestinal inflammation.

Sphingolipid biosynthesis is essential for metabolic rewiring during TH17 cell differentiation

T helper 17 (TH17) cells are implicated in autoimmune diseases, and several metabolic processes are shown to be important for their development and function. In this study, we report an essential role for sphingolipids synthesized through the de novo pathway in TH17 cell development. Deficiency of SPTLC1, a major subunit of serine palmitoyl transferase enzyme complex that catalyzes the first and rate-limiting step of de novo sphingolipid synthesis, impaired glycolysis in differentiating TH17 cells by increasing intracellular reactive oxygen species (ROS) through enhancement of nicotinamide adenine dinucleotide phosphate oxidase 2 activity. Increased ROS leads to impaired activation of mammalian target of rapamycin C1 and reduced expression of hypoxia-inducible factor 1-alpha and c-Myc-induced glycolytic genes. SPTLCI deficiency protected mice from developing experimental autoimmune encephalomyelitis and experimental T cell transfer colitis. Our results thus show a critical role for de novo sphingolipid biosynthetic pathway in shaping adaptive immune responses with implications in autoimmune diseases.

Claudin-7 is essential for the maintenance of colonic stem cell homoeostasis via the modulation of Wnt/Notch signalling

Intestinal stem cells (ISCs) play a crucial role in the continuous self-renewal and recovery of the intestinal epithelium. In previous studies, we have revealed that the specific absence of Claudin-7 (Cldn-7) in intestinal epithelial cells (IECs) can lead to the development of spontaneous colitis. However, the mechanisms by which Cldn-7 maintains homeostasis in the colonic epithelium remain unclear. Therefore, in the present study, we used IEC- and ISC-specific Cldn-7 knockout mice to investigate the regulatory effects of Cldn-7 on colonic Lgr5+ stem cells in the mediation of colonic epithelial injury and repair under physiological and inflammatory conditions. Notably, our findings reveal that Cldn-7 deletion disrupts the self-renewal and differentiation of colonic stem cells alongside the formation of colonic organoids in vitro. Additionally, these Cldn-7 knockout models exhibited heightened susceptibility to experimental colitis, limited epithelial repair and regeneration, and increased differentiation toward the secretory lineage. Mechanistically, we also established that Cldn-7 facilitates the proliferation, differentiation, and organoid formation of Lgr5+ stem cells through the maintenance of Wnt and Notch signalling pathways in the colonic epithelium. Overall, our study provides new insights into the maintenance of ISC function and colonic epithelial homoeostasis.

Charting the cellular biogeography in colitis reveals fibroblast trajectories and coordinated spatial remodeling

Gut inflammation involves contributions from immune and non-immune cells, whose interactions are shaped by the spatial organization of the healthy gut and its remodeling during inflammation. The crosstalk between fibroblasts and immune cells is an important axis in this process, but our understanding has been challenged by incomplete cell-type definition and biogeography. To address this challenge, we used multiplexed error-robust fluorescence in situ hybridization (MERFISH) to profile the expression of 940 genes in 1.35 million cells imaged across the onset and recovery from a mouse colitis model. We identified diverse cell populations, charted their spatial organization, and revealed their polarization or recruitment in inflammation. We found a staged progression of inflammation-associated tissue neighborhoods defined, in part, by multiple inflammation-associated fibroblasts, with unique expression profiles, spatial localization, cell-cell interactions, and healthy fibroblast origins. Similar signatures in ulcerative colitis suggest conserved human processes. Broadly, we provide a framework for understanding inflammation-induced remodeling in the gut and other tissues.

Revisiting the Role of Valeric Acid in Manipulating Ulcerative Colitis

BACKGROUND

Ulcerative colitis (UC) is characterized by a complicated interaction between mucosal inflammation, epithelial dysfunction, abnormal activation of innate immune responses, and gut microbiota dysbiosis. Though valeric acid (VA), one type of short-chain fatty acids (SCFAs), has been identified in other inflammatory disorders and cancer development, the pathological role of VA and underlying mechanism of VA in UC remain under further investigation.

METHODS

Studies of human clinical specimens and experimental colitis models were conducted to confirm the pathological manifestations of the level of SCFAs from human fecal samples and murine colonic homogenates. Valeric acid-intervened murine colitis and a macrophage adoptive transfer were applied to identify the underlying mechanisms.

RESULTS

In line with gut microbiota dysfunction in UC, alteration of SCFAs from gut microbes were identified in human UC patients and dextran sodium sulfate -induced murine colitis models. Notably, VA was consistently negatively related to the disease severity of UC, the population of monocytes, and the level of interluekin-6. Moreover, VA treatment showed direct suppressive effects on lipopolysaccharides (LPS)-activated human peripheral blood mononuclear cells and murine macrophages in the dependent manner of upregulation of GPR41 and GPR43. Therapeutically, replenishment of VA or adoptive transfer with VA-modulated macrophages showed resistance to dextran sodium sulfate-driven murine colitis though modulating the production of inflammatory cytokine interleukin-6.

CONCLUSIONS

In summary, the research uncovered the pathological role of VA in modulating the activation of macrophages in UC and suggested that VA might be a potential effective agent for UC patients.

Regulatory role of PI16 in autoimmune arthritis and intestinal inflammation: implications for Treg cell differentiation and function

BACKGROUND

Regulatory T cells (Tregs) are crucial in maintaining immune homeostasis and preventing autoimmunity and inflammation. A proportion of Treg cells can lose Foxp3 expression and become unstable under inflammation conditions. The precise mechanisms underlying this phenomenon remain unclear.

METHODS

The PI16 gene knockout mice (PI16fl/flFoxp3Cre) in Treg were constructed, and the genotypes were identified. The proportion and phenotypic differences of immune cells in 8-week-old mice were detected by cell counter and flow cytometry. Two groups of mouse Naïve CD4+T cells were induced to differentiate into iTreg cells to observe the effect of PI16 on the differentiation and proliferation of iTreg cells, CD4+CD25+Treg and CD4+CD25- effector T cells (Teff) were selected and co-cultured with antigen presenting cells (APC) to observe the effect of PI16 on the inhibitory ability of Treg cells in vitro. The effects of directed knockout of PI16 in Treg cells on inflammatory symptoms, histopathological changes and immune cell expression in mice with enteritis and autoimmune arthritis were observed by constructing the model of antigen-induced arthritis (AIA) and colitis induced by dextran sulfate sodium salt (DSS).

RESULTS

We identified peptidase inhibitor 16 (PI16) as a negative regulator of Treg cells. Our findings demonstrate that conditional knock-out of PI16 in Tregs significantly enhances their differentiation and suppressive functions. The conditional knockout of the PI16 gene resulted in a significantly higher abundance of Foxp3 expression (35.12 ± 5.71% vs. 20.00 ± 1.61%, p = 0.034) in iTreg cells induced in vitro compared to wild-type mice. Mice with Treg cell-specific PI16 ablation are protected from autoimmune arthritis (AIA) and dextran sulfate sodium (DSS)-induced colitis development. The AIA model of PI16CKO is characterized by the reduction of joint structure and the attenuation of synovial inflammation and in DSS-induced colitis model, conditional knockout of the PI16 reduce intestinal structural damage. Additionally, we found that the deletion of the PI16 gene in Treg can increase the proportion of Treg (1.46 ± 0.14% vs. 0.64 ± 0.07%, p < 0.0001) and decrease the proportion of Th17 (1.00 ± 0.12% vs. 3.84 ± 0.64%, p = 0.001). This change will enhance the shift of Th17/Treg toward Treg cells in AIA arthritis model (0.71 ± 0.06% vs. 8.07 ± 1.98%, p = 0.003). In DSS-induced colitis model of PI16CKO, the proportion of Treg in spleen was significantly increased (1.40 ± 0.15% vs. 0.50 ± 0.11%, p = 0.003), Th17 (2.18 ± 0.55% vs. 6.42 ± 1.47%, p = 0.017), Th1 (3.42 ± 0.19% vs. 6.59 ± 1.28%, p = 0.028) and Th2 (1.52 ± 0.27% vs. 2.76 ± 0.38%, p = 0.018) in spleen was significantly decreased and the Th17/Treg balance swift toward Treg cells (1.44 ± 0.50% vs. 24.09 ± 7.18%, p = 0.012).

CONCLUSION

PI16 plays an essential role in inhibiting Treg cell differentiation and function. Conditional knock out PI16 gene in Treg can promote the Treg/Th17 balance towards Treg dominance, thereby alleviating the condition. Targeting PI16 may facilitate Treg cell-based therapies for preventing autoimmune diseases and inflammatory diseases. The research provides us with novel insights and future research avenues for the treatment of autoimmune diseases, particularly arthritis and colitis.

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

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

pH-responsive CuS/DSF/EL/PVP nanoplatform alleviates inflammatory bowel disease in mice via regulating gut immunity and microbiota

The clinical treatment of inflammatory bowel disease (IBD) is challenging. We developed copper sulfate (CuS)/disulfiram (DSF)/methacrylic acid-ethyl acrylate copolymer (EL)/polyvinylpyrrolidone (PVP) nanoplatform (CuS/DSF/EL/PVP) and evaluated its efficiency for treating IBD. After oral administration, the pH-sensitive EL protected the CuS/DSF/EL/PVP against degradation by acidic gastric juices. Once the colon was reached, EL was dissolved, releasing DSF and Cu2+. Further, the main in vivo metabolite of DSF can bind to Cu2+ and form copper (II) N, N-diethyldithiocarbamate (CuET), which significantly alleviated acute colitis in mice. Notably, CuS/DSF/EL/PVP outperformed CuS/EL/PVP and DSF/EL/PVP nanoplatforms in reducing colonic pathology and improving the secretion of inflammation-related cytokines (such as IL-4 and IL-10) in the colonic mucosa. RNA-seq analysis revealed that the nanoplatform reduced colonic inflammation and promoted intestinal mucosal repair by upregulating C-type lectin receptor (CLR)-related genes and signaling pathways. Furthermore, CuS/DSF/EL/PVP showed potential for improving colitis Th1/Th17 cells through innate immunity stimulation, down-regulation of inflammatory cytokines, and upregulation of anti-inflammatory cytokines. Additionally, the intervention with CuS/DSF/EL/PVP led to increased intestinal flora diversity, decreased Escherichia-Shigella abundance, and elevated levels of short-chain fatty acid (SCFA)-producing bacteria Prevotella, Lactobacillus, and Bifidobacterium, indicating their potential to modulate the dysregulated intestinal flora and suppress inflammation. STATEMENT OF SIGNIFICANCE: Our study introduces the CuS/DSF/EL/PVP nanoplatform as a therapeutic strategy for treating inflammatory bowel disease (IBD). This approach demonstrates significant efficacy in targeting the colon and alleviating acute colitis in mice. It uniquely modulates gut immunity and microbiota, exhibiting a notable impact on inflammation-related cytokines and promoting intestinal mucosal repair. The nanoplatform's ability to regulate gut flora diversity, combined with its cost-effective and scalable production, positions it as a potentially transformative treatment for IBD, offering new avenues for personalized medical interventions.

Screening and characterization of an anti-inflammatory pectic polysaccharide from Cucurbita moschata Duch

Pectin polysaccharides have demonstrated diverse biological activities, however, the inflammatory potential of pectin polysaccharides extracted from Cucurbita moschata Duch remains unexplored. This study aims to extract, characterize and evaluate the effects of pumpkin pectin polysaccharide on lipopolysaccharide (LPS)-induced inflammatory response in RAW264.7 cells and dextran sulfate sodium (DSS)-induced colitis in mice, along with its underlying mechanism of action. Initially, we extracted three fractions of pectin polysaccharides from pumpkin and screened them for anti-inflammatory activity in LPS-induced macrophages, identifying CMDP-3a as the most potent anti-inflammatory fraction. Subsequently, CMDP-3a underwent comprehensive characterization through chromatography and spectroscopic analysis, revealing CMDP-3a as an RG-I-HG type pectin polysaccharide with →4)-α-D-GalpA-(1 → and →4)-α-D-GalpA-(1 → 2,4)-α-L-Rhap-(1 → as the main chain. Further, in the LPS-induced RAW264.7 cells model, treatment with CMDP-3a significantly down-regulated the mRNA expression of inducible nitric oxide synthase (iNOS), cyclooxygenase-2 (COX-2), and pro-inflammatory cytokines (IL-1β, TNF-α, and IL-6) by inhibiting the MAPK and NF-κB signaling pathways. Finally, in a mouse colitis model, CMDP-3a administration obviously inhibited DSS-induced pathological alterations and reduced inflammatory cytokine expressions in the colonic tissues by down-regulating the TLR4/NF-κB and MAPK pathways. These findings provide a molecular basis for the potential application of CMDP-3a in reducing inflammatory responses.

Telmisartan loading thermosensitive hydrogel repairs gut epithelial barrier for alleviating inflammatory bowel disease

Inflammatory bowel disease (IBD) remains a global health concern with a complex and incompletely understood pathogenesis. In the course of IBD development, damage to intestinal epithelial cells and a reduction in the expression of tight junction (TJ) proteins compromise the integrity of the intestinal barrier, exacerbating inflammation. Notably, the renin-angiotensin system and angiotensin II receptor type 1 (AT1R) play a crucial role in regulating the pathological progression including vascular permeability, and immune microenvironment. Thus, Telmisartan (Tel), an AT1R inhibitor, loading thermosensitive hydrogel was constructed to investigate the potential of alleviating inflammatory bowel disease through rectal administration. The constructed hydrogel exhibits an advantageous property of rapid transformation from a solution to a gel state at 37°C, facilitating prolonged drug retention within the gut while mitigating irritation associated with rectal administration. Results indicate that Tel also exhibits a beneficial effect in ameliorating colon shortening, colon wall thickening, cup cell lacking, crypt disappearance, and inflammatory cell infiltration into the mucosa in colitis mice. Moreover, it significantly upregulates the expression of TJ proteins in colonic tissues thereby repairing the intestinal barrier damage and alleviating the ulcerative colitis (UC) disease process. In conclusion, Tel-loaded hydrogel demonstrates substantial promise as a potential treatment modality for IBD.

Colitis induced by IL-17A-inhibitors

BACKGROUND

Interleukin (IL)-17A is essential for intestinal mucosal integrity, contributing to the prevention of detrimental immunity such as infectious colitis and inflammatory bowel disease (IBD). Indeed, neutralization of IL-17A has been abandoned as a therapeutic principle in IBD because of increased disease activity. However, it is controversial whether IL-17A inhibitors increase the risk of developing colitis in patients who do not have underlying IBD. Here, we present two cases of different forms of colitis that occurred during treatment with two IL-17A inhibitors, secukinumab and ixekizumab.

CASE PRESENTATIONS

We report the case of a 35-year-old female with SAPHO (synovitis-acne-pustulosis-hyperostosis-osteitis) syndrome who was admitted due to severe colitis with bloody diarrhea, fever, abdominal pain and weight loss after receiving secukinumab for 3 months as well as the case of a 41-year-old male with psoriatic arthritis who presented himself to the outpatient clinic with bloody stools, abdominal pain and nausea 5 months after changing his therapy from secukinumab to ixekizumab. In both patients, treatment with IL-17A-inhibitors was stopped and tumor necrosis factor inhibitors were started. Both patients recovered, are clinically stable and show no more signs of active colitis.

CONCLUSION

The role of IL-17A inhibitors in the pathogenesis of infectious colitis and new-onset IBD is not fully understood and requires further research. Patients receiving IL-17A-inhibitor therapy should be carefully screened and notified of the possible side effects.

Gα12 and endoplasmic reticulum stress-mediated pyroptosis in a single cycle of dextran sulfate-induced mouse colitis

Inflammatory bowel disease (IBD) pathogenesis involves complex inflammatory events and cell death. Although IBD involves mainly necrosis in the digestive tract, pyroptosis has also been recognized. Nonetheless, the underlying basis is elusive. Gα12/13 overexpression may affect endoplasmic reticulum (ER) stress. This study examined how Gα12/13 and ER stress affect pyroptosis using dextran sulfate sodium (DSS)-induced colitis models. Gα12/13 levels were increased in the distal and proximal colons of mice exposed to a single cycle of DSS, as accompanied by increases of IRE1α, ATF6, and p-PERK. Moreover, Il-6, Il-1β, Ym1, and Arg1 mRNA levels were increased with caspase-1 and IL-1β activation, supportive of pyroptosis. In the distal colon, RIPK1/3 levels were enhanced to a greater degree, confirming necroptosis. By contrast, the mice subjected to three cycles of DSS treatments showed decreases of Gα12/13, as accompanied by IRE1α and ATF6 suppression, but increases of RIPK1/3 and c-Cas3. AZ2 treatment, which inhibited Gα12, has an anti-pyroptotic effect against a single cycle of colitis. These results show that a single cycle of DSS-induced colitis may cause ER stress-induced pyroptosis as mediated by Gα12 overexpression in addition to necroptosis, but three cycles model induces only necroptosis, and that AZ2 may have an anti-pyroptotic effect.

Sophocarpine alleviates intestinal fibrosis via inhibition of inflammation and fibroblast into myofibroblast transition by targeting the Sirt1/p65 signaling axis

In this study, we used alkaloids from Sophora flavescens to inhibit the SASP, leading to fibroblast-into-myofibroblast transition (FMT) to maintain intestinal mucosal homeostasis in vitro and in vivo. We used western blotting (WB) and immunofluorescence staining (IF) to assess whether five kinds of alkaloids inhibit the major inflammatory pathways and chose the most effective compound (sophocarpine; SPC) to ameliorate colorectal inflammation in a dextran sulfate sodium (DSS)-induced UC mouse model. IF, Immunohistochemistry staining (IHC), WB, disease activity index (DAI), and enzyme-linked immunosorbent assay (ELISA) were conducted to investigate the mechanism of action of this compound. Next, we detected the pharmacological activity of SPC on the senescence-associated secretory phenotypes (SASP) and FMT in interleukin 6 (IL-6)-induced senescence-like fibroblasts and discussed the mucosal protection ability of SPC on a fibroblast-epithelium/organoid coculture system and organ-on-chip system. Taken together, our results provide evidence that SPC alleviates the inflammatory response, improves intestinal fibrosis and maintains intestinal mucosal homeostasis in vivo. Meanwhile, SPC was able to prevent IL-6-induced SASP and FMT in fibroblasts, maintain the expression of TJ proteins, and inhibit inflammation and genomic stability of colonic mucosal epithelial cells by activating SIRT1 in vitro. In conclusion, SPC treatment attenuates intestinal fibrosis by regulating SIRT1/NF-κB p65 signaling, and it might be a promising therapeutic agent for inflammatory bowel disease.

Targeting P2Y14R protects against necroptosis of intestinal epithelial cells through PKA/CREB/RIPK1 axis in ulcerative colitis

Purinergic signaling plays a causal role in the pathogenesis of inflammatory bowel disease. Among purinoceptors, only P2Y14R is positively correlated with inflammatory score in mucosal biopsies of ulcerative colitis patients, nevertheless, the role of P2Y14R in ulcerative colitis remains unclear. Here, based on the over-expressions of P2Y14R in the intestinal epithelium of mice with experimental colitis, we find that male mice lacking P2Y14R in intestinal epithelial cells exhibit less intestinal injury induced by dextran sulfate sodium. Mechanistically, P2Y14R deletion limits the transcriptional activity of cAMP-response element binding protein through cAMP/PKA axis, which binds to the promoter of Ripk1, inhibiting necroptosis of intestinal epithelial cells. Furthermore, we design a hierarchical strategy combining virtual screening and chemical optimization to develop a P2Y14R antagonist HDL-16, which exhibits remarkable anti-colitis effects. Summarily, our study elucidates a previously unknown mechanism whereby P2Y14R participates in ulcerative colitis, providing a promising therapeutic target for inflammatory bowel disease.

Hippocampal and gut AMPK activation attenuates enterocolitis-like symptoms and co-occurring depressive-like behavior in ulcerative colitis model mice: Involvement of brain-gut autophagy

Patients with inflammatory bowel disease, including ulcerative colitis (UC) and Crohn's disease, have a high incidence of psychiatric disorders, including depression and anxiety. However, the underlying pathogenic mechanism remains unknown. Dextran sulfate sodium (DSS)-treated mice, a model of UC, exhibit depressive-like behavior and reduced adenosine monophosphate-activated protein kinase (AMPK) activity, which regulates various physiological functions in the brain and gut. However, comprehensive studies on UC pathophysiology with co-occurring depression focused on brain-gut AMPK activity are lacking. Therefore, we aimed to investigate whether resveratrol (RES), an AMPK activator, prevented DSS-induced UC-like symptoms and depressive-like behavior. DSS treatment induced UC-like pathology and depressive-like behavior, as assessed via the tail suspension test. Moreover, western blotting and immunohistochemical studies revealed that DSS increased p-p70S6 kinase (Thr389), p62, tumor necrosis factor-α, interleukin (IL)-1β, IL-18, NLR family pyrin domain containing 3 (NLRP3), cleaved caspase-1, cleaved Gasdermin-D (GSDMD), and cleaved caspase-3 expression levels in the rectum and hippocampus, and increased CD40, iNOS, and Kelch-like ECH-associated protein 1 expression levels, and the number of Iba1-positive cells in the hippocampus, and decreased p-AMPK and LC3II/I expression levels, and the number of NF-E2-related factor 2 (Nrf2)-positive cells, and reduced neurogenesis in the hippocampus. These changes were reversed by the RES administration. RES also enhanced PGC1α and SOD1 expression in the hippocampus of DSS-treated male mice. Moreover, NLRP3 staining was observed in the neurons and microglia, and cleaved GSDMD staining in neurons in the hippocampus of DSS-treated mice. Notably, RES prevented UC-like pathology and depressive-like behavior and enhancement of autophagy, decreased rectal and hippocampal inflammatory cytokines and inflammasome, and induced the Nrf2-PGC1α-SOD1 pathway in the hippocampus, resulting in neurogenesis in the hippocampal dentate gyrus. Our findings suggest that brain-gut AMPK activation may be an important therapeutic strategy in patients with UC and depression.

Resveratrol alleviates inflammatory bowel disease by inhibiting JAK2/STAT3 pathway activity via the reduction of O-GlcNAcylation of STAT3 in intestinal epithelial cells

The role of O-linked N-acetylglucosamine (O-GlcNAc) modification (O-GlcNAcylation) in the pathogenesis of inflammatory bowel disease (IBD) has been increasingly highlighted in recent studies. It's been reported that signal transducer and activator of transcription 3 (STAT3) O-GlcNAcylation can affect the activity of the Janus kinase2 (JAK2)/STAT3 pathway.Our recent study showed that resveratrol repairsIBDin mice.On this basis,the present study aimed to explore whether the mechanism of IBD repair by resveratrol is associated with STAT3 O-GlcNAcylation. Pretreatment of colitis mice and intestinal epithelial cells with an O-GlcNAcylation promoter (Thiamet G, or Glucosamine) and an O-GlcNAcylation inhibitor (OSMI-1) showed that increased O-GlcNAcylation promoted colitis in mice.The pro-inflammatory cytokines interleukin (IL) -6, IL-1β, and tumor necrosis factor-α (TNF-α) were increased, while the anti-inflammatory cytokine IL-10 was decreased. Moreover, the downstream target proteins of JAK2/STAT3, cyclooxygenase-2 and nitric oxide synthase 2 were up-regulated, Resveratrol treatment mitigated the inflammation by decreasing JAK2/STAT3 activity, as well as STAT3 O-GlcNAcylation. Finally, the correlation between STAT3 glycosylation and phosphorylation in intestinal epithelial cells under the effect of resveratrol was investigated by Immunofluorescence co-localization and immunoprecipitation.The results showed that resveratrol inhibited STAT3 O-GlcNAcylation, thereby inhibiting its phosphorylation, reducing JAK2/STAT3 pathway activity, and alleviating IBD.

Forsythia suspensa polyphenols regulate macrophage M1 polarization to alleviate intestinal inflammation in mice

BACKGROUND

Inflammatory bowel disease (IBD) was a chronic intestinal disease related to autoimmunity, and its pathogenesis was complex. Forsythia suspensa (F. suspensa) had good anti-inflammatory and antioxidant effects. The active component polyphenols had significant effects in the treatment of intestinal inflammation. Researches had found that polarization, pyroptosis and apoptosis of macrophages can drive the occurrence and development of colitis.

PURPOSE

In this study, we examined whether F. suspensa polyphenols (FPP) mitigated DSS-induced colitis, and explored its potential mechanisms.

METHODS

The potential targets of F. suspensa in intestinal inflammation were predicted through network pharmacology. Using LPS and IFN-γ induced macrophage M1 polarization in J774A.1 cells. Macrophage polarization was detected through RT-qPCR, flow cytometry and ELISA. Ulcerative colitis (UC) in mice was induced by 2.5% DSS for 7 days, and then oral administrated different doses of FPP for another 7 days. Then we assessed the body weight, diarrhea, bleeding in stool, colon length, cytokines of serum and pathology of colon. The effects of FPP on the gut microbiota in mice also tested and evaluated.

RESULTS

Our results showed that the main active ingredient of F. suspensa in protecting intestinal inflammation were polyphenols and F. suspensa was multi-targeted in the treatment of intestinal inflammation. FPP inhibited M1 polarization and polarizes towards M2 in J774A.1 cells. FPP inhibited pyroptosis and apoptosis to exert anti-inflammatory effects. FPP had a good protective effect on DSS induced UC in mice. In unison, FPP inhibited M1 polarization, apoptosis, and pyroptosis in UC mice. FPP regulated intestinal homeostasis in mice with UC by improving the gut microbiota and enhancing the intestinal metabolites short-chain fatty acid (SCFAs).

CONCLUSIONS

These data indicated that FPP may alleviate UC by inhibiting M1 polarization in mice. Collectively, these findings suggest that the reduction of colitis by FPP may related to macrophage polarization, pyroptosis and apoptosis.

Effect of chronic low-dose treatment with chitooligosaccharides on microbial dysbiosis and inflammation associated chronic ulcerative colitis in Balb/c mice

The study aimed to investigate the potential of low dose chitooligosaccharide (COS) in ameliorating dextran sodium sulfate (DSS) induced chronic colitis by regulating microbial dysbiosis and pro-inflammatory responses. Chronic colitis was induced in BALB/c mice by DSS (4% w/v, 3 cycles of 5 days) administration. The mice were divided into four groups: vehicle, DSS, DSS + mesalamine and DSS+COS. COS and mesalamine were administered orally, daily once, from day 1 to day 30 at a dose of 20 mg/kg and 50 mg/kg respectively. The disease activity index (DAI), colon length, histopathological score, microbial composition, and pro-inflammatory cytokine expression were evaluated. COS (20 mg/kg, COSLow) administration reduced the disease activity index, and colon shortening, caused by DSS significantly. Furthermore, COSLow restored the altered microbiome in the gut and inhibited the elevated pro-inflammatory cytokines (IL-1 and IL-6) in the colon against DSS-induced chronic colitis in mice. Moreover, COSLow treatment improved the probiotic microflora thereby restoring the gut homeostasis. In conclusion, this is the first study where microbial dysbiosis and pro-inflammatory responses were modulated by chronic COSLow treatment against DSS-induced chronic colitis in Balb/c mice. Therefore, COS supplementation at a relatively low dose could be efficacious for chronic inflammatory bowel disease.

Gut microbiota modulation and effects of a diet enriched in apple pomace on inflammation in a DSS-induced colitis mouse model

Certain types of soluble dietary fibre, such as pectin and pectic oligosaccharides from different sources, have demonstrated protective effects against inflammation in DSS-induced colitis mouse models. In this work, we have evaluated the impact of a diet enriched in apple pomace (AP-diet), an agricultural by-product with a significant content of pectin and that previously demonstrated prebiotic properties in human fecal batch fermentation models, on the gut microbiota composition, intestinal damage and inflammation markers in a DSS-induced colitis model. We found that the apple pomace enriched diet (AP-diet), providing a significant amount of pectin with demonstrated prebiotic properties, was associated with a slower increase in the disease activity index, translating into better clinical symptomatology of the animals. Histological damage scoring confirmed less severe damage in those animals receiving an AP-diet before and during the DSS administration period. Some serum inflammatory markers, such as TNFα, also demonstrated lower levels in the group receiving the AP-diet, compared to the control diet. AP-diet administration is also associated with the modulation of key taxa in the colonic microbiota of animals, such as some Lachnospiraceae genera and Ruminococcus species, including commensal short chain fatty acid producers that could play a role in attenuating inflammation at the intestinal level.

Tiron ameliorates acetic acid-induced colitis in rats: Role of TGF-β/EGFR/PI3K/NF-κB signaling pathway

BACKGROUND

Ulcerative colitis (UC), an ongoing inflammatory disorder of the colon, is marked by persistent mucosal surface irritation extending from the rectum to the near-proximal colon. Tiron is a synthetic analogue of vitamin E which is known to have antioxidant and anti-inflammatory effects in various animal models, so the goal of this study was to find out whether Tiron had any preventive impacts on UC inflicted by acetic acid (A.A) exposure in rats.

METHOD

Tiron (235 and 470 mg/kg) was administered intra-peritoneally for 2 weeks, and A.A (2 ml, 3 % v/v) was injected intra-rectally to cause colitis. Colon tissues and blood samples were then collected for measurement of various inflammatory and oxidative stress biomarkers.

RESULTS

Tiron administration significantly diminished lactate dehydrogenase (LDH), C-reactive protein (CRP), colon weight, and the weight/length ratio of the colon as compared to A.A-injected rats. Additionally, Tiron attenuated oxidative stress biomarkers. Tiron also enforced the levels of Glucagon-like peptide-1 (GLP-1) and trefoil factor-3 (TFF-3), while it greatly lowered the expression of nuclear factor kappa B (NF-κB), interleukin-6 (IL-6), interferon-γ (IFN-γ), and transforming growth factor-1(TGF-β1), phosphorylated epidermal growth factor receptor (P-EGFR), phosphatidylinositol-3-kinase (PI3K) and protein kinase B (AKT) expression in colonic cellular structures. Furthermore, colonichistopathologic damages, revealed by hematoxylin and eosin (H&E) and Alcian Blue stain, were significantly decreased upon Tiron administration.

CONCLUSION

Tiron prevented A.A-induced colitis in rats via modulating inflammatory pathway TGF-β1/P-EGFR/PI3K/AKT/NF-κB, alongside managing the oxidant/antioxidant equilibrium, and boosting the reliability of the intestinal barrier.

Corin deficiency alleviates mucosal lesions in a mouse model of colitis induced by dextran sulfate sodium

AIMS

High dietary salt consumption is a risk factor for inflammatory bowel disease (IBD). Corin is a protease that activates atrial natriuretic peptide (ANP), thereby regulating sodium homeostasis. Corin acts in multiple tissues, including the intestine. In mice, corin deficiency impairs intestinal sodium excretion. This study aims to examine if reduced intestinal sodium excretion alters the pathophysiology of IBD.

MAIN METHODS

Wild-type (WT), Corin knockout (KO), and Corin kidney conditional KO (kcKO) mice were tested in a colitis model induced by dextran sulfide sodium (DSS). Effects of ANP on DSS-induced colitis were tested in WT and Corin KO mice. Body weight changes in the mice were monitored. Necropsy, histological analysis, and immunostaining studies were conducted to examine colon length and mucosal lesions. Fecal sodium levels were measured. RT-PCR was done to analyze proinflammatory genes in colon samples.

KEY FINDINGS

DSS-treated Corin KO mice had an ameliorated colitis phenotype with less body weight loss, longer colon lengths, smaller mucosal lesions, lower disease scores, more preserved goblet cells, and suppressed proinflammatory genes in the colon. In longitudinal studies, the DSS-treated Corin KO mice had delayed onset of colon mucosal lesions. ANP administration lessened the colitis in WT, but not Corin KO, mice. Analyses of WT, Corin KO, and Corin kcKO mice indicated that fecal sodium excretion, controlled by intestinal corin, may regulate inflammatory responses in DSS-induced colitis in mice.

SIGNIFICANCE

Our findings indicate a role of corin in intestinal pathophysiology, suggesting that reduced intestinal sodium level may offer protective benefits against IBD.

EFHD2 suppresses intestinal inflammation by blocking intestinal epithelial cell TNFR1 internalization and cell death

TNF acts as one pathogenic driver for inducing intestinal epithelial cell (IEC) death and substantial intestinal inflammation. How the IEC death is regulated to physiologically prevent intestinal inflammation needs further investigation. Here, we report that EF-hand domain-containing protein D2 (EFHD2), highly expressed in normal intestine tissues but decreased in intestinal biopsy samples of ulcerative colitis patients, protects intestinal epithelium from TNF-induced IEC apoptosis. EFHD2 inhibits TNF-induced apoptosis in primary IECs and intestinal organoids (enteroids). Mice deficient of Efhd2 in IECs exhibit excessive IEC death and exacerbated experimental colitis. Mechanistically, EFHD2 interacts with Cofilin and suppresses Cofilin phosphorylation, thus blocking TNF receptor I (TNFR1) internalization to inhibit IEC apoptosis and consequently protecting intestine from inflammation. Our findings deepen the understanding of EFHD2 as the key regulator of membrane receptor trafficking, providing insight into death receptor signals and autoinflammatory diseases.

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

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

A quinoa peptide protects impaired mucus barriers in colitis mice by inhibiting NF-κB-TRPV1 signaling and regulating the gut microbiota

Inflammatory bowel diseases (IBD) are chronic inflammatory conditions that lead to the disruption of the colonic mucus barrier. Quinoa has a well-balanced profile of essential amino acids and exhibits excellent anti-inflammatory effects. We recently explored the beneficial effects and relevant mechanisms of a novel quinoa peptide TPGAFF on impaired mucus barriers in mice with chemically induced colitis. Our findings demonstrated that TPGAFF, administered in low and high doses for 28 days, effectively attenuated the pathological phenotype and reduced intestinal permeability in colitis mice. TPGAFF demonstrated its protective abilities by restoring the impaired mucus barrier, inhibiting the activation of inflammatory signaling and reducing inflammatory cytokine levels. Moreover, TPGAFF positively influenced the composition of the gut microbiota by reducing inflammation-related microbes. Additionally, TPGAFF inhibited the activation of TRPV1 nociceptor and decreased the levels of neuropeptides. Conclusively, our results indicated that oral administration of TPGAFF may be an optional approach for the treatment of mucus barrier damage.

Structural characterization of a polysaccharide from Alhagi honey and its protective effect against inflammatory bowel disease by modulating gut microbiota dysbiosis

The Alhagi honey polysaccharide (AHP) exhibits notable anti-inflammatory, antioxidant, and immunomodulatory properties, positioning it as a promising candidate in traditional Chinese medicine. In this investigation, we successfully isolated and purified a neutral AHP, designated AHPN50-1a, subsequently elucidating its structural attributes. AHPN50-1a was found to have a molecular weight of 1.756 × 106 Da, featuring a structural motif characterized by a recurring (1→6)-α-GlcP linker. To comprehensively evaluate its therapeutic potential, we explored the protective effects of AHPN50-1 in a murine model of dextran sodium sulfate-induced colitis. Administration of AHPN50-1 at doses of 200 and 400 mg/kg/day resulted in improved food intake, increased body weight, and increased colon length in mice with acute colitis. Simultaneously, a reduction in the disease activity index and histological scores was observed. AHPN50-1 effectively mitigated colon tissue damage, down-regulated the expression levels of pro-inflammatory cytokines (IL-1β, IL-6, TNF-α) in colon tissue, restored intestinal microbiota diversity, and concentrations of short-chain fatty acids (SCFAs) of gut microbiota metabolites, thus alleviating intestinal inflammation in mice. In summary, our findings underscore the promise of AHPN50-1 as a valuable nutritional or dietary supplement for the treatment and prevention of inflammatory bowel disease.

Bacteroides thetaiotaomicron and its inactivated bacteria ameliorate colitis by inhibiting macrophage activation

BACKGROUND

Studies have demonstrated that Bacteroides thetaiotaomicron (BT) has protective effect against colon inflammation in murine models. Macrophages play an important role in gut immunity. However, the specific mechanisms of BT on macrophage are still unelucidated. Thus, our study investigates the anti-inflammatory effect of BT and its heat-treated inactivated bacteria on experimental colitis and macrophages.

METHODS

A dextran sulfate sodium (DSS)-induced acute colitis model with male C57BL/6 mice, BT (ATCC29148) strain, THP1 cell lines were used in this study. Live and heat-treated inactivated BT (IBT) solution (1 × 10^9cfu/ml) were intragastrically gavaged daily for 14 days. Colonic inflammation was determined by the disease activity index (DAI) score, colon length, histological score, and inflammatory factors. THP1 cells were induced towards M1, then treated with different concentrations of inactivated BT solution and p38 inhibitor. Western blotting, immunohistochemistry, immunofluorescence and qRT-PCR were performed to assess the levels of inflammatory cytokines and molecules of MAPK pathway including IL-6, TNF-α, IL-1β, IL-22, p38 and phosphor-p38 expressions. Moreover, 16S rRNA sequencing of colitis murine fecal samples was applied to investigate the influence of supplementation of BT to the gut microbiota homeostasis.

RESULTS

Both live and heat-treated inactivated BT decreased the DAI and histological scores as well as levels of inflammatory factors, particularly IL-6 while increasing IL-22 of DSS-induced colitis murine models. The cell experiments showed that inactivated BT downregulates IL-6 expression in THP1 via inhibiting p38 phosphorylation and affecting M1 polarization. Moreover, the 16S rRNA sequencing results showed that BT and IBT gavage could increase beta-diversity of gut flora in DSS-induced colitis mice. Furthermore, the significance test for differences between the groups showed that BT could increase Faecalebaculum, Lactobacillus and Bacteroides, while decreasing Akkermansia.

CONCLUSION

In summary, our findings imply that BT and its heat-treated inactivated bacteria exert a protective effect by suppressing macrophage-induced IL-6 through the inhibition of p38 MAPK pathway and ameliorating intestinal gut dysbiosis in experimental colitis.

Regulation of the intestinal flora using polysaccharides from Callicarpa nudiflora Hook to alleviate ulcerative colitis and the molecular mechanisms involved

Ulcerative colitis (UC) is a type of inflammatory bowel disease (IBD) that cannot be completely cured by current treatments. C. nudiflora Hook has antibacterial, anti-inflammatory, and hemostatic biological functions; however, the therapeutic role of C. nudiflora Hook or its extracts in IBD remains poorly understood. In this study, we extracted and purified three fractions of C. nudiflora Hook polysaccharides by hydroalcohol precipitation method, which were named as CNLP-1, CNLP-2 and CNLP-3, respectively. CNLP-2, the main component of the polysaccharides of C. nudiflora Hook is an pyranose type acidic polysaccharide composed of Fuc, Rha, Ara, Gal, Glc, Xyl, Man, Gal-UA and Glc-UA, with an Mn of 15.624 kDa; Mw of 31.375 kDa. CNLP-2 was found to have a smooth lamellar structure as observed by scanning electron microscopy. To investigate the effect of CNLP-2 (abbreviated to CNLP) on dextran sodium sulfate (DSS)-induced UC mice and its mechanism of action, we treated DSS-induced UC mice by administering CNLP at a dose of 100 mg/kg every other day. The results of the study showed that CNLP alleviated the clinical symptoms such as body weight (BW) loss, pathological damage, and systemic inflammation. The mechanism may be through the regulation of intestinal flora and its metabolism, which in turn affects the expression of NF-κB/MAPK pathway-related proteins through the metabolites of intestinal flora to further alleviate inflammation and ultimately improve the intestinal barrier function in UC mice. In conclusion, CNLP has great potential for the treatment of IBD.

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.

Labetalol Ameliorates Experimental Colitis in Rat Possibly Through its Effect on Proinflammatory Mediators and Oxidative Stress

BACKGROUND

Members of beta blockers drugs possess significant antioxidant activities. The current research is to assess the effect of the labetalol on acetic acid (AA-induced) colitis in rat model.

METHODS

Forty adult Wistar rats were separated into 4 groups, including the negative control group, AA group, AA + sulfasalazine (100 mg/kg/day) group, and AA + labetalol (300 mg/kg/day) group. Colitis was induced in rats by the interrectal installation of 2 mL of 4% (v/v) AA. Sulfasalazine and labetalol were administered orally for 7 days after 2 hours of induction. The following parameters were measured: disease activity index (DAI), histopa-thological changes and colon tissue homogenate concentrations of proinflammatory mediators IL-1β, adhesion molecules ICAM-1, and oxidative stress marker myeloperoxidase (MPO).

RESULTS

The treatment with labetalol significantly reduced DAI and histopathological changes induced by AA. Also, labetalol markedly decreased the concentrations of IL-1β, ICAM-1, and MPO in colonic tissue that were increased by AA. The effects of labetalol were significantly lower than that produced by sulfasalazine as standard drug.

CONCLUSIONS

Labetalol exerts ameliorative effects on disease activity and histopathological features of AA-induced colitis in rats possibly through antioxidant effects and inhibition of inflammatory mediators.

Quality of Surveillance Impacts the Colitis-Associated Advanced Neoplasia Risk: A Multicenter Case-Control Study

BACKGROUND AND AIMS

Although colorectal cancer (CRC) surveillance is embedded in clinical inflammatory bowel disease (IBD) practice, a subset of patients still develops advanced neoplasia (AN) (high-grade dysplasia [HGD] and/or CRC). We aimed to assess the impact of surveillance quality on AN risk in IBD.

METHODS

In this multicenter case-control study, we searched the Dutch nationwide pathology databank to identify IBD cases with AN and controls with indefinite or low-grade dysplasia. The surveillance colonoscopy preceding the index lesion (first indefinite for dysplasia [IND]/low-grade dysplasia [LGD] or AN) was used to assess the impact of surveillance quality. We assessed intervals, bowel preparation, cecal intubation, and absence of inflammation as primary quality indicators. In addition, we assessed chromoendoscopy, endoscopist expertise, hospital setting, and biopsy strategy. Associations of quality indicators with AN risk were determined with multivariable logistic regression analyses with Firth's correction.

RESULTS

We included 137 cases and 138 controls. Delayed intervals (58.2% vs 39.6%) and active inflammation (65.3% vs 41.8%) were frequently present in cases and controls and were associated with AN (delayed interval: adjusted odds ratio [aOR], 2.00; 95% confidence interval [CI], 1.07-3.81; P = .03; active inflammation: aOR, 2.46; 95% CI, 1.33-4.61; P < .01). Surveillance compliant with primary quality indicators was associated with a reduced AN risk (aOR, 0.43; 95% CI, 0.22-0.91; P = .03), similar to chromoendoscopy (OR, 0.11; 95% CI, 0.01-0.89; P = .01). Other indicators were not significantly associated with AN.

CONCLUSIONS

Surveillance compliant with primary quality indicators is associated with a reduced colitis-associated AN risk. Delayed surveillance intervals and active inflammation were associated with an increased AN risk. This underlines the importance of procedural quality, including endoscopic remission to optimize the effectiveness of endoscopic surveillance.

Choline metabolism in regulating inflammatory bowel disease-linked anxiety disorders: A multi-omics exploration of the gut-brain axis

Anxiety and depression caused by inflammatory bowel disease (IBD) negatively affect the mental health of patients. Emerging studies have demonstrated that the gut-brain axis (GBA) mediates IBD-induced mood disorders, but the underlying mechanisms of these findings remain unknown. Therefore, it's vital to conduct comprehensive research on the GBA in IBD. Multi-omics studies can provide an understanding of the pathological mechanisms of the GBA in the development of IBD, helping to uncover the mechanisms underlying the onset and progression of the disease. Thus, we analyzed the prefrontal cortex (PFC) of Dextran Sulfate Sodium Salt (DSS)-induced IBD mice using transcriptomics and metabolomics. We observed increased mRNA related to acetylcholine synthesis and secretion, along with decreased phosphatidylcholine (PC) levels in the PFC of DSS group compared to the control group. Fecal metagenomics also revealed abnormalities in the microbiome and lipid metabolism in the DSS group. Since both acetylcholine and PC are choline metabolites, we posited that the DSS group may experience choline deficiency and choline metabolism disorders. Subsequently, when we supplemented CDP-choline, IBD mice exhibited improvements, including decreased anxiety-like behaviors, reduced PC degradation, and increased acetylcholine synthesis in the PFC. In addition, administration of CDP-choline can restore imbalances in the gut microbiome and disruptions in lipid metabolism caused by DSS treatment. This study provides compelling evidence to suggest that choline metabolism plays a crucial role in the development and treatment of mood disorders in IBD. Choline and its metabolites appear to have a significant role in maintaining the stability of the GBA.

Integrated Metabolomics and Gut Microbiome Analysis Reveals the Efficacy of a Phytochemical Constituent in the Management of Ulcerative Colitis

SCOPE

Cinnamaldehyde (CAH), a phytochemical constituent isolated from cinnamon, is gaining attention due to its nutritional and medicinal benefits. This study aimed to investigate the potential role of CAH in the treatment of ulcerative colitis (UC).

METHODS AND RESULTS

Integrated metabolomics and gut microbiome analysis are performed for 2,4,6-trinitrobenzenesulfonic acid (TNBS) induced UC rats. The effect of CAH on colonic inflammation, lipid peroxidation, metabolic profiles, and gut microbiota is systematically explored. It finds that CAH improves the colitis-related symptoms, decreases disease activity index, increases the colon length and body weight, and alleviates histologic inflammation of UC rats. These therapeutic effects of CAH are due to suppression of inflammation and lipid peroxidation. Moreover, multi-omics analysis reveals that CAH treatment cause changes in plasma metabolome and gut microbiome in UC rats. CAH regulates lipid metabolic processes, especially phosphatidylcholines, lysophosphatidylcholines, and polyunsaturated fatty acids. Meanwhile, CAH modulates the gut microbial structure by restraining pathogenic bacteria (such as Helicobacter) and increasing probiotic bacteria (such as Bifidobacterium and Lactobacillus).

CONCLUSIONS

These results indicate that CAH exerts a beneficial role in UC by synergistic modulating the balance in gut microbiota and the associated metabolites, and highlights the nutritional and medicinal value of CAH in UC management.

The alleviative effect of C-phycocyanin peptides against TNBS-induced inflammatory bowel disease in zebrafish via the MAPK/Nrf2 signaling pathways

INTRODUCTION

Ulcerative colitis (UC) is an incurable and highly complex chronic inflammatory bowel disease (IBD) affecting millions of people worldwide. C-phycocyanin (C-PC) has been reported to possess outstanding anti-inflammatory activities and can effectively inhibit various inflammation-related diseases. Whether C-PC-derived bioactive peptides can inhibit intestinal inflammation is worth research and consideration.

METHODS

The inhibition activities of three anti-neuroinflammatory peptides were evaluated using 2-4-6-trinitrobenzen sulfonic acid (TNBS)-induced zebrafish colitis model. Subsequently, the abilities of peptides to promote gastrointestinal motility were also examined. The changes in the intestinal pathological symptoms and ultrastructure of intestinal, reactive oxygen species (ROS) levels, and antioxidant enzymes were then determined after co-treatment with peptides and TNBS. Transcriptome analysis was used to investigate the underlying ameliorating TNBS-induced colitis effects molecular mechanisms of better activity peptide. Furthermore, quantitative reverse-transcription polymerase chain reaction and molecular docking techniques verified the mRNA sequencing results.

RESULTS

Three peptides, MHLWAAK, MAQAAEYYR and MDYYFEER, which significantly inhibit macrophage migration, were synthesized. The results showed that these peptides could effectively alleviate the inflammatory responses in the TNBS-induced zebrafish model of colitis. In addition, co-treatment with TNBS and C-PC peptides could decrease ROS production and increase antioxidant enzyme activities in zebrafish larvae. Moreover, MHLWAAK had the most significantly therapeutic effects on colitis in zebrafish. The transcriptome analysis suggests that the effect of MHLWAAK on TNBS-induced colitis may be associated with the modulation of nuclear factor-erythroid 2-related factor 2 (Nrf2) and mitogen-activated protein kinase (MAPK) signaling pathway associated genes. In addition, molecular docking was conducted to study the prospective interaction between peptides and the key proteins that streamline the Nrf2 and MAPK signaling pathways. IL-6, JNK3, TNF-α, KEAP1-NRF2 complex and MAPK may be the core targets of MHLWAAK in treating colitis.

CONCLUSION

The results suggested that the three C-PC-derived peptides could ameliorate TNBS-induced colitis in zebrafish, and these peptides might be a promising therapeutic candidate for UC treatment.

Deficiency of inflammation-sensing protein neuropilin-2 in myeloid-derived macrophages exacerbates colitis via NF-κB activation

Neuropilin-2 (NRP2) is a multifunctional protein engaged in the regulation of angiogenesis, lymphangiogenesis, axon guidance, and tumor metastasis, but its function in colitis remains unclear. Here, we found that NRP2 was an inflammation-sensing protein rapidly and dramatically induced in myeloid cells, especially in macrophages, under inflammatory contexts. NRP2 deficiency in myeloid cells exacerbated dextran sulfate sodium salt-induced experimental colitis by promoting polarization of M1 macrophages and colon injury. Mechanistically, NRP2 could be induced via NF-κB activation by TNF-α in macrophages, but exerted an inhibitory effect on NF-κB signaling, forming a negative feedback loop with NF-κB to sense and alleviate inflammation. Deletion of NRP2 in macrophages broke this negative feedback circuit, leading to NF-κB overactivation, inflammatory exacerbation, and more severe colitis. Collectively, these findings reveal inflammation restriction as a role for NRP2 in macrophages under inflammation contexts and suggest that NRP2 in macrophages may relieve inflammation in inflammatory bowel disease. © 2023 The Pathological Society of Great Britain and Ireland.

Klebsiella aerogenes exacerbates colon tumorigenesis in the AOM/DSS-induced C57BL/6J mouse

Klebsiella aerogenes (K. aerogenes, KA) is a gram-negative opportunistic pathogen from the Klebsiella species and the Enterobacteriaceae family. However, the impact of K. aerogenes on colorectal cancer (CRC) remains uncertain. A colitis-associated tumorigenesis animal model was established by administering azoxymethane (AOM) and dextran sulfate sodium (DSS) to C57BL/6J mice. The concentration of K. aerogenes gavage in mice was 109 cfu. The study measured the following parameters: tumor formation (number and size), intestinal permeability (MUC2, ZO-1, and Occludin), colonic inflammation (TNF-α, IL-1β, IL-6, and IL-10), proliferation and the fluctuation of the intestinal flora. Under the AOM/DSS-treated setting, K. aerogenes colonization worsened colitis by exacerbating intestinal inflammatory reaction and destroying the mucosal barrier. The intervention markedly augmented the quantity and dimensions of neoplasm in the AOM/DSS mice, stimulated cellular growth, and impeded cellular programmed cell death. In addition, K. aerogenes exacerbated the imbalance of the intestinal microbiota by elevating the abundance of Pseudomonas, Erysipelatoclostridium, Turicibacter, Rikenella, and Muribaculum and leading to a reduction in the abundance of Odoribacter, Alloprevotella, Roseburia, and Lachnospiraceae_NK4A136_group. The presence of K. aerogenes in AOM/DSS-treated mice promoted tumorigenesis, worsened intestinal inflammation, disrupted the intestinal barrier, and caused disturbance to the gut microbiota.

Porcine-derived antimicrobial peptide PR39 alleviates DSS-induced colitis via the NF-κB/MAPK pathway

PR39 is an antimicrobial peptide (AMP) with a variety of biological functions, including antimicrobial, wound healing, leukocyte chemotaxis, angiogenesis, and immunomodulation; however, its therapeutic efficacy in colitis (IBD) has rarely been reported. For this reason, the present study aimed to investigate the therapeutic effect of PR39 on IBD and its underlying mechanisms. In this experiment, a mouse model of ulcerative colitis (UC) was induced with 3 % dextran sulfate (DSS) and administered by rectal injection of PR39. The results of the study showed that 5 mg/kg of PR39 was able to ameliorate the clinical manifestations of DSS-induced UC mice by improving the clinical symptoms, colonic tissue damage, up-regulating the expression of tight junction proteins, and alleviating the systemic inflammation in mice in various ways. The mechanism of action may involve inhibition of the phosphorylation level of proteins related to the NF-κB/MAPK signaling pathway and modulation of the relative abundance of potentially pathogenic (Bacteroides, Pseudoflavonifractor, Barnesiella, and Oscillibacter) and potentially beneficial bacteria (Candidatus_Saccharibacteria, Desulfovibrio, Saccharibacteria) in the intestinal flora. The results enriched the biological functions of PR-39 and also suggested that PR-39 may be able to be used as a novel drug for the treatment of IBD.

Circular RNA Cdr1as inhibits proliferation and delays injury-induced regeneration of the intestinal epithelium

Circular RNAs (circRNAs) are highly expressed in the mammalian intestinal epithelium, but their functions remain largely unknown. Here, we identified the circRNA Cdr1as as a repressor of intestinal epithelial regeneration and defense. Cdr1as levels increased in mouse intestinal mucosa after colitis and septic stress, as well as in human intestinal mucosa from patients with inflammatory bowel disease and sepsis. Ablation of the Cdr1as locus from the mouse genome enhanced renewal of the intestinal mucosa, promoted injury-induced epithelial regeneration, and protected the mucosa against colitis. We found approximately 40 microRNAs, including miR-195, differentially expressed between intestinal mucosa of Cdr1as-knockout (Cdr1as-/-) versus littermate mice. Increasing the levels of Cdr1as inhibited intestinal epithelial repair after wounding in cultured cells and repressed growth of intestinal organoids cultured ex vivo, but this inhibition was abolished by miR-195 silencing. The reduction in miR-195 levels in the Cdr1as-/- intestinal epithelium was the result of reduced stability and processing of the precursor miR-195. These findings indicate that Cdr1as reduces proliferation and repair of the intestinal epithelium at least in part via interaction with miR-195 and highlight a role for induced Cdr1as in the pathogenesis of unhealed wounds and disrupted renewal of the intestinal mucosa.

Traditional Chinese Medicine: A promising strategy to regulate the imbalance of bacterial flora, impaired intestinal barrier and immune function attributed to ulcerative colitis through intestinal microecology

ETHNOPHARMACOLOGICAL RELEVANCE

Globally, plant materials are widely used as an additional and alternative therapy for the treating of diverse diseases. Ulcerative colitis (UC) is a chronic, recurrent and nonspecific inflammation of the bowel, referred to as "modern intractable disease" according to the World Health Organization. With the continuous development of theoretical research in Traditional Chinese Medicine (TCM) and the advantages of TCM in terms of low side effects, TCM has shown great progress in the research of treating UC.

AIM OF THIS REVIEW

This review aimed to explore the correlation between intestinal microbiota and UC, summarize research advances in TCM for treating UC, and discuss the mechanism of action of TCM remedies in regulating intestinal microbiota and repairing damaged intestinal barrier, which will provide a theoretical basis for future studies to elucidate the mechanism of TCM remedies based on gut microbiota and provide novel ideas for the clinical treatment of UC.

METHODS

We have collected and collated relevant articles from different scientific databases in recent years on the use of TCM in treating UC in relation to intestinal microecology. Based on the available studies, the therapeutic effects of TCM are analysed and the correlation between the pathogenesis of UC and intestinal microecology is explored.

RESULTS

TCM is used to further protect the intestinal epithelium and tight junctions, regulate immunity and intestinal flora by regulating intestinal microecology, thereby achieving the effect of treating UC. Additionally, TCM remedies can effectively increase the abundance of beneficial bacteria that produce short-chain fatty acids, decrease the abundance of pathogenic bacteria, restore the balance of intestinal microbiota, and indirectly alleviate intestinal mucosal immune barrier dysfunction and promote the repair of damaged colorectal mucosa.

CONCLUSION

Intestinal microbiota is closely related to UC pathogenesis. The alleviation of intestinal dysbiosis can be a potential novel therapeutic strategy for UC. TCM remedies can exert protective and therapeutic effects on UC through various mechanisms. Although intestinal microbiota can aid in the identification of different TCM syndromes types, further studies are needed using modern medical technology. This will improve the clinical therapeutic efficacy of TCM remedies in UC and promote the application of precision medicine.

Aqueous M. oleifera leaf extract alleviates DSS-induced colitis in mice through suppression of inflammation

ETHNOPHARMACOLOGICAL RELEVANCE

Moringa oleifera Lam. (M. oleifera) is a perennial deciduous tree with considerable agricultural and pharmacological value. Nearly all parts of the tree are edible, and nearly all parts are used in traditional medicine. Leaves of M. oleifera have the functions of hypoglycemic (antidiabetic), anti-cancer and anti-oxidant stress, but less research pay attention to the anti-inflammatory effect of M. oleifera leaves.

AIM OF THE STUDY

Inflammatory bowel disease (IBD) is a chronic and relapsing inflammatory disorder of the gut with no ideal medication. Here, we investigated the anti-inflammatory effects of aqueous extract of M. oleifera leaves.

MATERIALS AND METHODS

Intestinal organoids and mice as in vitro and in vivo models to investigate the effects of aqueous extract of M. oleifera leaves on inflammation induced by TNF-α and dextran sulfate sodium (DSS) respectively. The expression of inflammatory cytokines and proliferation-related genes were evaluated by RT-qPCR, respectively. The compounds in the leaf extract were determined by LC/MS, and network pharmacology approach was employed to predict 54 anti-IBD potential targets of quercetin-3-galactoside (QG) and isoquercitrin (IS).

RESULTS

We found that the extract protected against damage to intestinal organoids caused by tumor necrosis factor (TNF-α), and significantly down-regulated the expression of inflammatory cytokines. The extract also suppressed the TNF-α-induced expression of Pcna, c-Myc, and c-Jun. Additionally, oral administration of the extract also ameliorated DSS-induced colon damage (colonic shortening, loss of goblet cells and overall abnormal cellularity), and inhibited the expression of inflammatory cytokines and proliferation-related genes in colitis. By LC/MS we identified nearly 2000 of the compounds in the leaf extract, of the flavonoids identified, QG and IS made up the largest percentage; both have been shown to have anti-inflammatory properties. Moreover, network pharmacology approach was employed to predict 54 anti-IBD potential targets of QG and IS. Gene Ontology (GO) enrichment and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis indicated that the overlapping targets participated in response to oxidative stress and PI3K-Akt signaling pathway respectively.

CONCLUSIONS

The present study demonstrated the anti-inflammatory capability, in vitro and in vivo, of the aqueous extract of M. oleifera leaves and suggests its potential phytotherapeutic treatment for IBD.

Extracellular Matrix Orchestration of Tissue Remodeling in the Chronically Inflamed Mouse Colon

BACKGROUND & AIMS

Chronic inflammatory illnesses are debilitating and recurrent conditions associated with significant comorbidities, including an increased risk of developing cancer. Extensive tissue remodeling is a hallmark of such illnesses, and is both a consequence and a mediator of disease progression. Despite previous characterization of epithelial and stromal remodeling during inflammatory bowel disease, a complete understanding of its impact on disease progression is lacking.

METHODS

A comprehensive proteomic pipeline using data-independent acquisition was applied to decellularized colon samples from the Muc2 knockout (Muc2KO) mouse model of colitis for an in-depth characterization of extracellular matrix remodeling. Unique proteomic profiles of the matrisomal landscape were extracted from prepathologic and overt colitis. Integration of proteomics and transcriptomics data sets extracted from the same murine model produced network maps describing the orchestrating role of matrisomal proteins in tissue remodeling during the progression of colitis.

RESULTS

The in-depth proteomic workflow used here allowed the addition of 34 proteins to the known colon matrisomal signature. Protein signatures of prepathologic and pathologic colitic states were extracted, differentiating the 2 states by expression of small leucine-rich proteoglycans. We outlined the role of this class and other matrisomal proteins in tissue remodeling during colitis, as well as the potential for coordinated regulation of cell types by matrisomal ligands.

CONCLUSIONS

Our work highlights a central role for matrisomal proteins in tissue remodeling during colitis and defines orchestrating nodes that can be exploited in the selection of therapeutic targets.

Prevalence of Enteric Infections in Patients on Immune Checkpoint Inhibitors and Impact on Management and Outcomes

BACKGROUND

Stool pathogen testing is recommended as part of the initial evaluation for patients with new-onset diarrhea on immune checkpoint inhibitors (ICIs), yet its significance has not been well-studied. We aimed to determine the impact of multiplex gastrointestinal (GI) pathogen PCR testing on the clinical course and use of immunosuppressive therapy in patients who develop diarrhea on ICIs.

METHODS

This retrospective cohort included individuals who underwent GI pathogen panel PCR for diarrhea on ICIs at Memorial Sloan Kettering between 7/2015 and 7/2021. The primary outcome was use of immunosuppressive therapy for suspected immunotherapy-related enterocolitis (irEC). Secondary outcomes included diarrhea severity and endoscopic and histologic disease patterns.

RESULTS

Among 521 ICI-treated patients tested for GI pathogens, 61 (11.7%) had a positive PCR. Compared to patients without detectable infections, patients with infections had more frequent grades 3-4 diarrhea (37.7% vs. 19.6%, P < .01) and colitis (39.3% vs. 14.7%, P < .01). However, patients with infections did not have higher rates of persistent or recurrent diarrhea and were less likely to receive steroids (P < .01) and second-line immunosuppressive agents (P = .03). In 105 patients with lower endoscopy, similar trends were observed and no differences in endoscopic severity or histologic patterns were noted between groups.

CONCLUSIONS

GI infections in ICI-treated patients presenting with diarrhea are linked to more severe but self-limited clinical presentations and may be optimally treated with observation and supportive care alone. Routine and timely stool pathogen testing may help avert unnecessary empiric immunosuppression for suspected irEC, which has been linked to blunted antitumor responses and numerous adverse effects.

Galectin from Trichinella spiralis alleviates DSS-induced colitis in mice by regulating the intestinal microbiota

According to numerous reports, Trichinella spiralis (T. spiralis) and its antigens can reduce intestinal inflammation by modulating regulatory immunological responses in the host to maintain immune homeostasis. Galectin has been identified as a protein that is produced by T. spiralis, and its characterization revealed this protein has possible immune regulatory activity. However, whether recombinant T. spiralis galectin (rTs-gal) can cure dextran sulfate sodium (DSS)-induced colitis remains unknown. Here, the ability of rTs-gal to ameliorate experimental colitis in mice with inflammatory bowel disease (IBD) as well as the potential underlying mechanism were investigated. The disease activity index (DAI), colon shortening, inflammatory cell infiltration, and histological damage were used as indicators to monitor clinical symptoms of colitis. The results revealed that the administration of rTs-gal ameliorated these symptoms. According to Western blotting and ELISA results, rTs-gal may suppress the excessive inflammatory response-mediated induction of TLR4, MyD88, and NF-κB expression in the colon. Mice with colitis exhibit disruptions in the gut flora, including an increase in gram-negative bacteria, which in turn can result in increased lipopolysaccharide (LPS) production. However, injection of rTs-gal may inhibit changes in the gut microbiota, for example, by reducing the prevalence of Helicobacter and Bacteroides, which produce LPS. The findings of the present study revealed that rTs-gal may inhibit signalling pathways that involve enteric bacteria-derived LPS, TLR4, and NF-κB in mice with DSS-induced colitis and attenuate DSS-induced colitis in animals by modulating the gut microbiota. These findings shed additional light on the immunological processes underlying the beneficial effects of helminth-derived proteins in medicine.

Upregulated Tβ4 expression in inflammatory bowel disease impairs the intestinal mucus barrier by inhibiting autophagy in mice

Disrupted intestinal barrier homeostasis is fundamental to inflammatory bowel disease. Thymosin β4 (Tβ4) improves inflammation and has beneficial effects in dry-eye diseases, but its effects on the intestinal mucus barrier remain unknown. Therefore, this study evaluated the underlying regulatory mechanisms and effects of Tβ4 by examining Tβ4 expression in a mouse model with dextran sodium sulfate (DSS)-induced colitis and colonic barrier damage. Additionally, we intraperitoneally injected C57BL/6 mice with Tβ4 to assess barrier function, microtubule-associated protein 1 light chain 3 (LC3II) protein expression, and autophagy. Finally, normal human colon tissue and colon carcinoma cells (Caco2) were cultured to verify Tβ4-induced barrier function and autophagy changes. Mucin2 levels decreased, microbial infiltration increased, and Tβ4 expression increased in the colitis mouse model versus the control mice, indicating mucus barrier damage. Moreover, Tβ4-treated C57BL/6 mice had damaged intestinal mucus barriers and decreased LC3II levels. Tβ4 also inhibited colonic mucin2 production, disrupted tight junctions, and downregulated autophagy; these results were confirmed in Caco2 cells and normal human colon tissue. In summary, Tβ4 may be implicated in colitis by compromising the integrity of the intestinal mucus barrier and inhibiting autophagy. Thus, Tβ4 could be a new diagnostic marker for intestinal barrier defects.

Microalgae polysaccharides exert antioxidant and anti-inflammatory protective effects on human intestinal epithelial cells in vitro and dextran sodium sulfate-induced mouse colitis in vivo

Microalgae polysaccharides (MAPS) have emerged as novel prebiotics, but their direct effects on intestinal epithelial barrier are largely unknown. Here, MAPS isolated from Chlorella pyrenoidosa, Spirulina platensis, and Synechococcus sp. PCC 7002 were characterized as mainly branched heteropolysaccharides, and were bioavailable to Caco-2 cells based on fluorescein isothiocyanate labeling and flow cytometry analysis. These MAPS were equally effective to scavenge hydroxyl and superoxide radicals in vitro and to attenuate the H2O2-, dextran sodium sulfate-, tumor necrosis factor α-, and interleukin 1β-induced burst of intracellular reactive oxygen species and mitochondrial superoxide radicals, interleukin-8 production, cyclooxygenase-2 and inducible nitric oxide synthase expression, and/or tight junction disruption in polarized Caco-2 cells. MAPS and a positive drug Mesalazine were intragastrically administered to C57BL/6 mice daily for 7 d during and after 4-d dextran sodium sulfate exposure. Clinical signs and colon histopathology revealed equivalent anti-colitis efficacies of MAPS and Mesalazine, and based on biochemical analysis of colonic tight junction proteins, goblet cells, mucin 2 and trefoil factor 3 transcription, and colonic and peripheral pro-inflammatory cytokines, MAPS alleviated dextran sodium sulfate-induced intestinal epithelial barrier dysfunction, and their activities were even superior than Mesalazine. Overall, MAPS confer direct antioxidant and anti-inflammatory protection to intestinal epithelial barrier function.

Edible pueraria lobata-derived exosome-like nanovesicles ameliorate dextran sulfate sodium-induced colitis associated lung inflammation through modulating macrophage polarization

BACKGROUND

Inflammatory bowel diseases (IBD), such as severe colitis, are associated with the development of lung inflammation and tissue damage. Pueraria lobata (P. lobata) plays an essential role in controlling cytokines. However, the exact mechanism of the inflammation response is still unknown.

PURPOSE

To investigate the effects of the P. lobata-derived exosomes-like nanovesicles (PLDENs) on colitis and their role in the lung inflammatory response.

METHODS

In this study, we investigated the effects of PLDENs on the dextran sulfate sodium (DSS)-induced colitis and explored the mechanisms by forming the gut-lung axis. PLDENs were characterized by mass spectrometry-based proteomic analysis.

RESULTS

The results showed that PLDENs had significant preventive effects in DSS-induced colitis and pathological changes in colons in a dose-dependent manner. Simultaneously, the treatment of PLDENs could effectively reduce inflammatory changes in the lung. PLDENs could selectively regulate the composition of gut microbiota.

CONCLUSION

These data suggested that the treatment of PLDENs could 'attenuate DSS-induced colitis and lung inflammation, providing an efficacious supplement for reducing co-morbidities in IBD patients.

The colitis may be microscopic, but the diarrhea is not: update on the treatment of microscopic colitis and immune checkpoint inhibitor colitis

PURPOSE OF REVIEW

Microscopic colitis is an inflammatory disease of the colon that presents as watery diarrhea with minimal to normal endoscopic changes on colonoscopy. It encompasses two common subtypes, lymphocytic colitis and collagenous colitis, which are both treated similarly.Immune checkpoint inhibitor colitis is among the most common immune-related adverse events. Endoscopic and histological findings range from normal colonic mucosa to inflammatory bowel like changes. This review article provides update in treatment and management of microscopic colitis and immune checkpoint inhibitor colitis (ICPi colitis).

RECENT FINDINGS

Recent studies on microscopic colitis have focused on the successful use of immunomodulators such as biologics for treatment of budesonide refractory microscopic colitis cases. Microscopic colitis does not confer an added risk for colorectal cancer.With the increasing usage of immunotherapy agents, immune checkpoint inhibitor colitis is becoming more common. ICPi colitis can be successfully managed with steroids, with treatment stepped up to biologics for moderate to severe cases or for mild cases that do not respond to steroids. Immunotherapy agents can be carefully re-introduced in mild cases, after treatment of ICPi colitis.

SUMMARY

Biologics can be used to treat budesonide refractory microscopic colitis. ICPi colitis can be managed with steroids and biologics in moderate to severe cases.

Protective role of estrogen through G-protein coupled receptor 30 in a colitis mouse model

Estrogen and its receptors are involved in the pathogenesis of gastrointestinal diseases such as colitis. However, the role of the membrane estrogen receptor G-protein-coupled receptor 30 (GPR30) in colitis is poorly understood. We therefore investigated the effect of estrogen in dextran sulfate sodium (DSS)-induced colitis. Male C57BL/6 mice were administered 1.5% DSS for 5 days and treated with 17β-estradiol (E2), GPR30 agonist (G1), or GPR30 antagonist (G15) for 8 days. Inflammation grade was evaluated by disease activity index (DAI) and histomorphological score. Colon tissues were immunohistochemically analyzed and revealed high expression of membrane GPR30, histone 3 lysine 36 dimethylation, and lysine 79 trimethylation in normal mouse colon epithelial cells but significantly decreased expression in DSS-treated mice, whereas the expression was partially preserved after treatment with E2 or G1. Colon shortening and DAI were significantly lower in E2- and G1-treated mice compared to DSS-treated mice. Caudal type homeobox 2 (CDX2) expression and cell proliferation differed in normal colon epithelial cells but overlapped in those of DSS-treated mice. Administration of E2 and G1 reduced CDX2 expression and cell proliferation. Altered expression of claudin-2 and occludin were observed in the colonic epithelium of DSS-treated mice, and these changes were significantly lower in the colon of E2- and G1-treated mice. These results indicate that estrogen regulates histone modification, cell proliferation, and CDX2 expression through GPR30, which affects intestinal epithelial barrier function. We conclude that estrogen protects against intestinal epithelial damage through GPR30 by enhancing intestinal epithelial barrier function in DSS-induced colitis in mice.