Suppression of dextran sulfate sodium-induced colitis in mice by radon inhalation

Atractylodes macrocephala Koidz Alleviates Symptoms in Zymosan-Induced Irritable Bowel Syndrome Mouse Model through TRPV1, NaV1.5, and NaV1.7 Channel Modulation

(1) Background: Irritable bowel syndrome (IBS) is a common disease in the gastrointestinal (GI) tract. Atractylodes macrocephala Koidz (AMK) is known as one of the traditional medicines that shows a good efficacy in the GI tract. (2) Methods: We investigated the effect of AMK in a network pharmacology and zymosan-induced IBS animal model. In addition, we performed electrophysiological experiments to confirm the regulatory mechanisms related to IBS. (3) Results: Various characteristics of AMK were investigated using TCMSP data and various analysis systems. AMK restored the macroscopic changes and weight to normal. Colonic mucosa and inflammatory factors were reduced. These effects were similar to those of amitriptyline and sulfasalazine. In addition, transient receptor potential (TRP) V1, voltage-gated Na+ (NaV) 1.5, and NaV1.7 channels were inhibited. (4) Conclusion: These results suggest that AMK may be a promising therapeutic candidate for IBS management through the regulation of ion channels.

Enterococcus durans 98D alters gut microbial composition and function to improve DSS-induced colitis in mice

Enterococcus durans, is a potential functional strain with the capacity to regulate intestinal health and ameliorate colonic inflammation. However, the strain requires further investigation regarding its safety profile and potential mechanisms of colitis improvement. In this study, the safety of E. durans 98D (Ed) as a potential probiotic was studied using in vitro methods. Additionally, a dextran sulfate sodium (DSS)-induced murine colitis model was employed to investigate its impact on the intestinal microbiota and colitis. In vitro antimicrobial assays revealed Ed sensitivity to common antibiotics and its inhibitory effect on the growth of Escherichia coli O157, Streptococcus pneumoniae CCUG 37328, and Staphylococcus aureus ATCC 25923. To elucidate the functional properties of Ed, 24 weight-matched 6-week-old female C57BL/6J mice were randomly divided into three groups (n = 8): NC group, Con group (DSS), and Ed group (DSS + Ed). Ed administration demonstrated a protective effect on colitis mice, as evidenced by improvements in body weight, colonic length, reduced disease activity index, histological scores, diminished splenomegaly, and decreased goblet cell loss. Furthermore, Ed downregulated the expression of the pro-inflammatory cytokine genes (IL-6, IL-1β, and TNF-α) and upregulated the expression of the anti-inflammatory cytokine gene IL-10. The 16S rRNA gene sequencing revealed significant alterations in microbial α-diversity, with principal coordinate analysis indicating distinct differences in microbial composition among the three groups. At the phylum level, the relative abundance of Actinomycetota significantly increased in the Ed-treated group. At the genus level, Ed treatment markedly elevated the relative abundance of Paraprevotella, Rikenellaceae_RC9, and Odoribacter in DSS-induced colitis mice. In conclusion, Ed exhibits potential as a safe and effective therapeutic agent for DSS-induced colitis by reshaping the colonic microbiota.

Undaria pinnatifida fucoidan ameliorates dietary fiber deficiency-induced inflammation and lipid abnormality by modulating mucosal microbiota and protecting intestinal barrier integrity

Dietary fiber deficiency (FD) is a new public health concern, with limited understanding of its impact on host energy requirements and health. In this study, the effect of fucoidan from Undaria pinnatifida (UPF) on FD-induced alterations of host physiological status was analyzed in mice. UPF increased colon length and cecum weight, reduced liver index, and modulated serum lipid metabolism primarily involving glycerophospholipid and linoleic acid metabolism in FD-treated mice. UPF protected against FD-induced destruction of intestinal barrier integrity by upregulating the expression levels of tight junction proteins and mucin-related genes. UPF alleviated FD-induced intestinal inflammation by reducing the levels of inflammation-related factors, such as interleukin-1β, tumor necrosis factor-α, and lipopolysaccharides, and relieving oxidative stress. The underlying mechanism can be closely associated with modulation of gut microbiota and metabolites, such as a reduction of Proteobacteria and an increase in short chain fatty acids. The in vitro model showed that UPF mitigated H2O2-induced oxidative stress and apoptosis in IEC-6 cells, indicating its potential as a therapeutic agent for inflammatory bowel disorders. This study suggests that UPF can be developed as a fiber supplement to benefit host health by modulating gut microbiota and metabolites and protecting intestinal barrier functions.

Bacteroides uniformis-induced perturbations in colonic microbiota and bile acid levels inhibit TH17 differentiation and ameliorate colitis developments

Inflammatory bowel disease (IBD) is associated with gut dysbiosis and can lead to colitis-associated malignancies. Bacteroides uniformis (Bu) regulates animal intestinal homeostasis; however, the mechanism by which it alleviates colitis in mice remains unknown. We investigated the effects of B. uniformis JCM5828 and its metabolites on female C57BL/6J mice with dextran sulfate sodium salt (DSS) induced colitis. Treatment with Bu considerably alleviated colitis progression and restored the mechanical and immune barrier protein expression. Additionally, Bu increased the abundance of the symbiotic bacteria Bifidobacterium and Lactobacillus vaginalis while decreasing that of pathogenic Escherichia-Shigella, and modulated intestinal bile acid metabolism. Bu largely regulated the expression of key regulatory proteins of the NF-κB and mitogen-activated protein kinase (MAPK) signaling pathways in colonic tissues and the differentiation of TH17 cells. However, Bu could not directly inhibit TH17 cell differentiation in vitro; it modulated the process in the lamina propria by participating in bile acid metabolism and regulating key metabolites (alpha-muricholic, hyodeoxycholic, and isolithocholic acid), thereby modulating the intestinal immune response. Our findings suggest that Bu or bile acid supplements are potential therapies for colitis and other diseases associated with intestinal barrier dysfunction.

Whole intestinal microbiota transplantation is more effective than fecal microbiota transplantation in reducing the susceptibility of DSS-induced germ-free mice colitis

Fecal microbiota transplantation (FMT) is an emerging and effective therapy for the treatment of inflammatory bowel disease (IBD). Previous studies have reported that compared with FMT, whole intestinal microbiota transplantation (WIMT) can more precisely replicate the community structure and reduce the inflammatory response of the host. However, it remains unclear whether WIMT is more effective in alleviating IBD. To examine the efficacy of WIMT and FMT in the intervention of IBD, GF (Germ-free) BALB/c mice were pre-colonized with whole intestinal microbiota or fecal microbiota before being treated with dextran sodium sulfate (DSS). As expected, the symptoms of colitis were alleviated by both WIMT and FMT, as demonstrated by the prevention of body weight loss and decreased the Disease activity index and histological scores in mice. However, WIMT's anti-inflammatory effect was superior to that of FMT. In addition, the inflammatory markers myeloperoxidase (MPO) and eosinophil peroxidase were dramatically downregulated by WIMT and FMT. Furthermore, the use of two different types of donors facilitated the regulation of cytokine homeostasis in colitis mice; the level of the pro-inflammatory cytokine IL-1β in the WIMT group was significantly lower than that in the FMT group, while the level of the anti-inflammatory factor IL-10 was significantly higher than that in the FMT group. Both groups showed enhanced expression of occludin to protect the intestinal barrier in comparison with the DSS group, and the WIMT group demonstrated considerably increased levels of ZO-1. The sequencing results showed that the WIMT group was highly enriched in Bifidobacterium, whereas the FMT group was significantly enriched in Lactobacillus and Ochrobactrum. Correlation analysis revealed that Bifidobacterium was negatively correlated with TNF-α, whereas Ochrobactrum was positively correlated with MPO and negatively correlated with IL-10, which might be related to different efficacies. Functional prediction using PICRUSt2 revealed that the FMT group was considerably enriched in the L-arginine biosynthesis I and L-arginine biosynthesis IV pathway, whereas the WIMT group was enriched in the L-lysine fermentation to acetate and butanoate pathway. In conclusion, the symptoms of colitis were subsided to varying degrees by the two different types of donors, with the WIMT group being more effective than the FMT group. This study provides new information on clinical interventions for IBD.

Apigenin and Exposure to Low Dose Gamma Radiation Ameliorate Acetic Acid-Induced Ulcerative Colitis in Rats

Ulcerative colitis (UC) is an inflammatory bowel disease involving chronic and recurring colon inflammation. Current management protocols are limited by adverse effects or short-term symptomatic relief. We aimed to investigate the possible therapeutic prospect of low dose gamma (γ) irradiation or apigenin treatment in acetic acid-induced UC in rats. Induction of UC was carried out by installation of acetic acid intra-rectally. One hour post-induction, rats received a sole dose of γ-radiation (0.5 Gray) or were treated with apigenin (3 mg/kg/day, peroral) for 7 successive days. Antioxidant and anti-inflammatory effects of both agents were assessed via determination of colon malondialdehyde (MDA), reduced glutathione (GSH), total nitrate/nitrite (NOx), mucosal addressin cell adhesion molecule-1 (MAdCAM-1), and interleukin-1beta (IL-1β) contents as well as myeloperoxidase (MPO) activity. Body weight (BW), colon weight/length (W/L) ratio, disease activity index (DAI), and histopathological changes were evaluated. Gamma irradiation and apigenin significantly ameliorated the acetic acid-induced biochemical and histopathological changes. Both therapeutic approaches significantly restored colon contents of the investigated biomarkers. They modulated BW, colon W/L ratio and DAI. This study proposes low dose γ-irradiation as a new therapeutic candidate for the management of UC. We also concluded that apigenin exhibited therapeutic benefits in UC management.

Oral delivery of layer-by-layer coated exosomes for colitis therapy

Mesenchymal stem cell-derived exosomes (MSC-Exos) have attracted much attention as a potential cell-free therapy for ulcerative colitis (UC), mainly due to their anti-inflammatory, tissue repair, and immunomodulatory properties. Although intravenous injection of MSC-Exos is able to improve UC to a certain extent, oral administration of exosomes is the preferred method to treat gastrointestinal diseases such as UC. However, exosomes contain proteins and nucleic acids that are vulnerable to degradation by the gastrointestinal environment, making oral administration difficult to implement. Layer-by-layer (LbL) self-assembly technology provides a promising strategy for the oral delivery of exosomes. Therefore, an efficient LbL-Exos self-assembly system was constructed in this study for the oral delivery of exosomes targeted to the colon to improve UC treatment. Biocompatible and biodegradable N-(2-hydroxyl) propyl-3-trimethyl ammonium chitosan chloride (HTCC) and oxidized konjac glucomannan (OKGM) polysaccharides were used as the outer layers to provide colon targeting and to protect exosomes from degradation. Similar to plain exosomes, LbL-Exos had a similar structure and features, but LbL provided controlled release of exosomes in the inflammatory colon. Compared with intravenous administration, oral administration of LbL-Exos could effectively alleviate UC using half the number of exosomes. Mechanistic studies showed that LbL-Exos were internalized by macrophages and intestinal epithelial cells to exert anti-inflammatory and tissue repair effects and therefore alleviate UC. Furthermore, the LbL-Exos system was able to improve UC via MAPK/NF-κB signaling pathway inhibition. Overall, our data show that LbL-MSC-Exos can alleviate UC after oral administration and therefore may constitute a new strategy for UC treatment in the future.

Pea Albumin Attenuates Dextran Sulfate Sodium-Induced Colitis by Regulating NF-κB Signaling and the Intestinal Microbiota in Mice

BACKGROUND

Inflammatory bowel disease remains a global burden with rapidly increasing incidence and prevalence in both industrialized countries and developing countries. In this study, we prepared pea albumin from pea seeds and determined its beneficial effects being anti-inflammatory and on gut microbiota modulation in dextran sulfate sodium (DSS)-challenged mice.

METHOD

Six-week-old C57BL/6N male mice received an equivalent volume (200 μL) of sterile phosphate balanced solution, 0.375, 0.75, or 1.50 g/kg body weight (BW) of pea albumin that was subjected to 2.0% DSS for 7 days to induce colitis. On day 17 of the experiment, all mice were sacrificed after blood sample collection, and colon tissue and colon contents were collected. BW change curve, colon length, myeloperoxidase (MPO) activity, mucus staining, immunofluorescence staining of T cells and macrophages, cytokines, pro-inflammatory genes expression, nuclear factor-κB (NF-κB) and signal transducer, and activator of transcription 3 (STAT3) signaling pathways as well as 16S DNA sequence were measured.

RESULTS

Our results show that pea albumin alleviates DSS-induced BW loss, colon length shortening, enhanced MPO activity, cytokines secretion, mucus deficiency, and inflammatory cell infiltration, as well as enhanced pro-inflammatory genes expression. In addition, the overactivation of NF-κB and STAT3 following DSS exposure is attenuated by pea albumin administration. Of particular interest, pea albumin oral administration restored gut microbiota dysbiosis as evidenced by enhanced α-diversity, restored β-diversity, and promoted relative abundance of Lactobacillus and Lachnospiraceae_NK4A136_group.

CONCLUSION

Taken together, the data provided herein demonstrated that pea albumin plays a protective role in DSS-induced colitis by reducing inflammatory cell infiltration, pro-inflammatory genes expression and pro-inflammatory cytokines release, inactivation of NF-κB signal, and gut microbiota modulation.

Immunomodulatory Effects of Radon Inhalation on Lipopolysaccharide-Induced Inflammation in Mice

Typical indications for radon therapy include autoimmune diseases such as rheumatoid arthritis (RA). We had previously reported that radon inhalation inhibits Th17 immune responses in RA mice by activating Th1 and Th2 immune responses. However, there are no reports on how radon inhalation affects the activated Th1 and Th17 immune responses, and these findings may be useful for identifying new indications for radon therapy. Therefore, in this study, we investigated the effect of radon inhalation on the lipopolysaccharide (LPS)-induced inflammatory response, focusing on the expression of related cytokines and antioxidant function. Male BALB/c mice were exposed to 2000 Bq/m³ radon for one day. Immediately after radon inhalation, LPS was administered intraperitoneally at 1.0 mg/kg body weight for 4 h. LPS administration increased the levels of Th1- and Th17-prone cytokines, such as interleukin-2, tumor necrosis factor-α, and granulocyte-macrophage colony-stimulating factor, compared to no treatment control (sham). However, these effects were suppressed by radon inhalation. IL-10 levels were significantly increased by LPS administration, with or without radon inhalation, compared to sham. However, radon inhalation did not inhibit oxidative stress induced by LPS administration. These findings suggest that radon inhalation has immunomodulatory but not antioxidative functions in LPS-induced injury.

Immunomodulatory effects of mixed Lactobacillus plantarum on lipopolysaccharide-induced intestinal injury in mice

The intestine is the largest digestive and immune organ in the human body, with an intact intestinal mucosal barrier. Lactobacillus plantarum is an important strain of probiotics in the intestine for boosting intestinal immunity to defend against intestinal injury. In the lipopolysaccharide-induced intestinal injury model, mixed L. plantarum (L. plantarum KLDS 1.0318, L. plantarum KLDS 1.0344, and L. plantarum KLDS 1.0386) was suggested to boost intestinal immunity. In detail, compared with LPS-induced mice, mice in the mixed L. plantarum group showed significantly reduced intestine (jejunum, ileum, and colon) tissue injury, pro-inflammatory cytokine (TNF-α, IL-6 and IL-12) levels, myeloperoxidase activities, and serum D-lactate (P < 0.05) content. Moreover, the mixed L. plantarum significantly increased the number of immunocytes (CD4+ T cells, IgA plasma cells) and the expression of tight junction proteins (Claudin1 and Occludin). The results also showed that the mixed L. plantarum significantly down-regulated (P < 0.05) the intestinal protein expression of TLR4, p-IκB, and NF-κB p65. The mixed L. plantarum group increased the relative abundance of the genera, including Lactobacillus, Lachnoclostridium, and Desulfovibrio, which are related to improving the levels of SCFAs (acetic acid, butyric acid) and total bile acid (P < 0.05). Overall, these results indicated that the mixed L. plantarum had great functionality in reducing LPS-induced intestinal injury.

RIP3 knockdown inhibits necroptosis of human intestinal epithelial cells via TLR4/MyD88/NF-κB signaling and ameliorates murine colitis

Background

Ulcerative colitis (UC) is a common inflammatory bowel disease, during which cell necroptosis plays key roles in driving inflammation initiation and aggravation. Previous studies reported Receptor Interacting Protein Kinase 3 (RIP3)-mediated necroptosis in multiple diseases, and RIP3 protein in Paneth cells significantly enriched in the intestines of both humans and mice. Therefore, we hypothesized targeting RIP3 to inhibit necroptosis may depress UC.

Methods

We classified clinical UC samples according to the modified Truelove & Witts criterion. The expression of RIP3 was measured by western blot and immunohistochemistry. Cell proliferation and apoptosis were analyzed by MTT assay and flow cytometry. ROS production and the secretion of inflammatory cytokines were measured by DCFH-DA probe and ELISA assay. TLR4/MyD88/NF-κB signaling pathway was analyzed by western blot. We established experimental colitis model in RIP3 knockout and wild-type mice and disease activity index (DAI) score was calculated. The expression and distribution of tight junction protein were analyzed by immunofluorescence. The ratio of CD4+Foxp3+ T cells in the spleen was detected by flow cytometry. Oxidative damage of mouse colon was assessed by detecting the levels of SOD, MDA and MPO. Data were analyzed by one-way ANOVA or student’s t test.

Results

The expression of RIP3 in human colon is positively associated with the severity of UC. RIP3 inhibitor GSK872 or RIP3 knockdown reverses the inhibitory effect of TNF-α on proliferation and the promoting effect of TNF-α on apoptosis and necrosis in human intestinal epithelial cells. In addition, RIP3 deficiency inhibits the secretion of inflammatory cytokines (IL-16, IL-17 and IFN-γ) and ROS production induced by TNF-α. In vivo, RIP3 inhibitor Nec-1 effectively improves DSS-induced colitis in mice. In mechanism, RIP3 depression could upregulate the proportion of CD4+Foxp3+ immunosuppressive Treg cells in the spleen while suppressed TLR4/MyD88/NF-κB signaling pathway and ROS generation, and all these anti-inflammation factors together suppress the secretion of inflammatory cytokines and necroptosis of intestinal epithelial cells.

Conclusions

This study preliminarily explored the regulating mechanism of RIP3 on UC, and Nec-1 may be a promising drug to alleviate the inflammation and necroptosis of the colon in UC patients.

Effects of dietary phosphatidylcholine and sphingomyelin on DSS-induced colitis by regulating metabolism and gut microbiota in mice

Patients with inflammatory bowel diseases tend to show alteration of lipid profiles. It remains unknown whether dietary intake with specific lipids, such as phosphatidylcholine (PC) and sphingomyelin (SM), have distinguishable effects against IBD. Here, a preclinical study using dextran sulphate sodium (DSS)-induced colitis mice model was applied to explore/compare the effects by PC and SM. Results showed that PC treatment (p.o., 30 mg/kg b.w., 15 days) exerted higher inhibitory activity than the same dosage of SM supplementation on colonic tissue lesions and pro-inflammatory cytokines expressions induced by DSS. Integrative analysis of the metabolome and microbiome indicated that PC and SM supplementation could modulate endogenous tryptophan metabolism, arginine and proline metabolism, purine metabolism, bile secretion, as well as vitamin digestion and absorption, closely correlated with their regulation on the abundance of Lactobacillus, Faecalibacterium, Dubosiella, Turicibacter, and Parasutterella communities in the gut. Based on these data, PC is a more promising candidate for preventing colitis than SM. Our findings provided a scientific foundation for further clinical research to screen more efficient dietary intervention strategy for colitis prevention.

Human Fecal Microbiota Transplantation Reduces the Susceptibility to Dextran Sulfate Sodium-Induced Germ-Free Mouse Colitis

In clinical practice, fecal microbiota transplantation (FMT) has been used to treat inflammatory bowel disease (IBD), and has shown certain effects. However, the selection of FMT donors and the mechanism underlying the effect of FMT intervention in IBD require further exploration. In this study, dextran sodium sulfate (DSS)-induced colitis mice were used to determine the differences in the protection of colitis symptoms, inflammation, and intestinal barrier, by FMT from two donors. Intriguingly, pre-administration of healthy bacterial fluid significantly relieved the symptoms of colitis compared to the ulcerative colitis (UC) bacteria. In addition, healthy donor (HD) bacteria significantly reduced the levels of inflammatory markers Myeloperoxidase (MPO) and Eosinophil peroxidase (EPO), and various pro-inflammatory factors, in colitis mice, and increased the secretion of the anti-inflammatory factor IL-10. Metagenomic sequencing indicated higher species diversity and higher abundance of anti-inflammatory bacteria in the HD intervention group, including Alistipes putredinis, Akkermansia muciniphila, Bifidobacterium adolescentis, short-chain fatty acids (SCFAs)-producing bacterium Christensenella minuta, and secondary bile acids (SBAs)-producing bacterium Clostridium leptum. In the UC intervention group, the SCFA-producing bacterium Bacteroides stercoris, IBD-related bacterium Ruminococcus gnavus, Enterococcus faecalis, and the conditional pathogen Bacteroides caccae, were more abundant. Metabolomics analysis showed that the two types of FMT significantly modulated the metabolism of DSS-induced mice. Moreover, compared with the UC intervention group, indoleacetic acid and unsaturated fatty acids (DHA, DPA, and EPA) with anti-inflammatory effects were significantly enriched in the HD intervention group. In summary, these results indicate that FMT can alleviate the symptoms of colitis, and the effect of HD intervention is better than that of UC intervention. This study offers new insights into the mechanisms of FMT clinical intervention in IBD.

Alginate oligosaccharides protect against fumonisin B1-induced intestinal damage via promoting gut microbiota homeostasis

Fumonisin B1 (FB1), one of the most common mycotoxins contaminating feed and food, has been shown to induce intestinal barrier degradation. However, its role on gut microbiota in this process is still unclear. Alginate oligosaccharides (AOS) have been reported to exert their anti-inflammatory and anti-apoptotic function partially via modulation the gut microbiota. However, little is known about the beneficial effect of AOS on gut microbiota upon FB1 exposure. Results show that FB1 degraded intestinal epithelial barrier function as evidenced by increased pathological epithelial cell shedding, reduced the number of goblet cells, and promoted intestinal cell apoptosis. Markedly, FB1 disturbed the cecal and fecal microbiota composition. FB1 increased the level of Lactobacillus and decreased the relative abundance of beneficial microbes. FB1 largely inhibited the production of short chain fatty acids (SCFAs). AOS greatly ameliorated FB1-induced intestinal damage, inflammation, and oxidative stress (eg., T-SOD and MDA). AOS alleviated gut microbial dysbiosis by promoting the growth of beneficial microbes such as Roseburia, Bifidobacterium, and Akkermansia, and increasing SCFAs production upon FB1 exposure. Moreover, the correlation analysis showed that FB1- and AOS-treated gut microbiota alteration is closely associated with the change of intestinal phenotype. We have thus provided a novel insight into the protective role of AOS on FB1-induced gut microbial dysbiosis.

The Periodontopathic Pathogen, Porphyromonas gingivalis, Involves a Gut Inflammatory Response and Exacerbates Inflammatory Bowel Disease

Periodontal disease (PD) is one of the most prevalent disorders globally and is strongly associated with many other diseases. Inflammatory bowel disease (IBD), an inflammatory condition of the colon and the small intestine, is reported to be associated with PD through undetermined mechanisms. We analyzed taxonomic assignment files from the Crohn’s Disease Viral and Microbial Metagenome Project (PRJEB3206). The abundance of Porphyromonadaceae in fecal samples was significantly different between patients with Crohn’s disease and control volunteers. Dextran sulfate sodium was used to induce colitis in mice to reveal the effect of this periodontopathic pathogen in vivo. After intrarectal implantation of Porphyromonas gingivalis (Pg)—the primary pathogen causing PD—the disease activity index score, colonic epithelial loss, and inflammatory cell infiltration were intensified. In addition, tumor necrosis factor-α and interleukin-6 showed the highest levels in Pg-infected colons. This revealed the importance of Pg in the exacerbation of IBD. Thus, simultaneous treatment of PD should be considered for people with IBD. Moreover, implantation of Pg in the rectum worsened the clinical symptoms of colitis in mice. Because Pg participates in the pathogenesis of IBD, reducing the chances of it entering the intestine might prevent the worsening of this disorder.

Mechanisms of action of radon therapy on cytokine levels in normal mice and rheumatoid arthritis mouse model

The typical indication of radon therapy is rheumatoid arthritis. Although there are several reports that radon therapy has regulation effects on Th17 cells, there has been no study reporting that radon inhalation affects the immune balance among Th1, Th2, and Th17. The purpose of this study is to examine the cytokine changes after radon inhalation. BALB/c mice inhaled radon at 2,000 Bq/m³ for 2 or 4 weeks. SKG/Jcl mice inhaled radon at 2,000 Bq/m³ for 4 weeks after zymosan administration. The results showed that radon inhalation for 4 weeks activated the immune response of Th1, Th2, and Th17. Moreover, the balance among them was not lost by radon inhalation. Radon inhalation for 4 weeks decreased superoxide dismutase activity and increased catalase activity in spleen. These findings suggest that an imbalance of oxidative stress may contribute to activate the immune response. Although zymosan administration activated Th17 immune response and decreased Th1 and Th2 immune response in SKG/Jcl mice, most cytokines related to Th1, Th2, and Th17 approached the normal level by radon inhalation. These findings suggested that radon inhalation has a different action between SKG/Jcl mice and normal BABL/c mice. This may indicate that radon inhalation has an immunomodulation function.

An Escherichia coli strain with extra catalase activity protects against murine colitis by scavenging hydrogen peroxide and regulating regulatory t cell/interleukin-17 pathways

BACKGROUND

Inflammatory bowel disease (IBD) is a chronic inflammatory disease of the gastrointestinal tract whose occurrence is attributed to various factors, including genetic factors, immune response, microbial changes, and oxidative stress. Microbial-targeted therapy has emerged as an alternative to immunosuppressive therapy for IBD.

METHODS

The effects of an atypical commensal Escherichia coli strain harboring an additional catalase gene (compared to typical E. coli strain) on dextran sulfate sodium (DSS)-induced colitis were explored in mice.

RESULTS

The atypical E. coli (atEc) significantly restored body weight, reduced disease activity score, and improved histological scores in mice with colitis. Hydrogen peroxide levels in colitis mice were noticeably decreased when the mice were administered atEc. The proinflammatory cytokine levels were decreased and regulatory T cell numbers were increased after the administration of atEc. The abundance of Firmicutes was significantly recovered, while that of Proteobacteria decreased in atEc -treated mice compared with that in vehicle-treated wild-type mice. To investigate the role of interleukin (IL)-17A in mediating the anti-inflammatory effects of the atEc, IL-17A‒knockout mice were orally administered atEc. Clinical and immune responses and microbial composition were significantly reduced in IL-17A‒knockout mice compared with those in wild-type mice.

CONCLUSIONS

atEc ameliorates colonic inflammation by controlling hydrogen peroxide levels, immune responses (including regulatory T cells and IL-17A), and microbial composition. atEc could be a novel candidate of probiotic for IBD treatment.

Radon inhalation decreases DNA damage induced by oxidative stress in mouse organs via the activation of antioxidative functions

Radon inhalation decreases the level of lipid peroxide (LPO); this is attributed to the activation of antioxidative functions. This activation contributes to the beneficial effects of radon therapy, but there are no studies on the risks of radon therapy, such as DNA damage. We evaluated the effect of radon inhalation on DNA damage caused by oxidative stress and explored the underlying mechanisms. Mice were exposed to radon inhalation at concentrations of 2 or 20 kBq/m3 (for one, three, or 10 days). The 8-hydroxy-2'-deoxyguanosine (8-OHdG) levels decreased in the brains of mice that inhaled 20 kBq/m3 radon for three days and in the kidneys of mice that inhaled 2 or 20 kBq/m3 radon for one, three or 10 days. The 8-OHdG levels in the small intestine decreased by approximately 20-40% (2 kBq/m3 for three days or 20 kBq/m3 for one, three or 10 days), but there were no significant differences in the 8-OHdG levels between mice that inhaled a sham treatment and those that inhaled radon. There was no significant change in the levels of 8-oxoguanine DNA glycosylase, which plays an important role in DNA repair. However, the level of Mn-superoxide dismutase (SOD) increased by 15-60% and 15-45% in the small intestine and kidney, respectively, following radon inhalation. These results suggest that Mn-SOD probably plays an important role in the inhibition of oxidative DNA damage.

Immunomodulatory role of Parkinson's disease 7 in inflammatory bowel disease

Recently the role of Parkinson’s disease 7 (PARK7) was studied in gastrointestinal diseases, however, the complex role of PARK7 in the intestinal inflammation is still not completely clear. Expression and localization of PARK7 were determined in the colon biopsies of children with inflammatory bowel disease (IBD), in the colon of dextran sodium sulphate (DSS) treated mice and in HT-29 colonic epithelial cells treated with interleukin (IL)-17, hydrogen peroxide (H₂O₂), tumor necrosis factor (TNF)-α, transforming growth factor (TGF)-β or lipopolysaccharide (LPS). Effect of PARK7 on the synthesis of IBD related cytokines was determined using PARK7 gene silenced HT-29 cells and 3,4,5-trimethoxy-N-(4-(8-methylimidazo(1,2-a)pyridine-2-yl)phenyl)benzamide (Comp23)—compound increasing PARK7 activity—treated mice with DSS-colitis. PARK7 expression was higher in the mucosa of children with Crohn’s disease compared to that of controls. While H₂O₂ and IL-17 treatment increased, LPS, TNF-α or TGF-β treatment decreased the PARK7 synthesis of HT-29 cells. PARK7 gene silencing influenced the synthesis of IL1B, IL6, TNFA and TGFB1 in vitro. Comp23 treatment attenuated the ex vivo permeability of colonic sacs, the clinical symptoms, and mucosal expression of Tgfb1, Il1b, Il6 and Il10 of DSS-treated mice. Our study revealed the role of PARK7 in the regulation of IBD-related inflammation in vitro and in vivo, suggesting its importance as a future therapeutic target.

Evaluation of the redox state in mouse organs following radon inhalation

Radon inhalation activates antioxidative functions in mouse organs, thereby contributing to inhibition of oxidative stress-induced damage. However, the specific redox state of each organ after radon inhalation has not been reported. Therefore, in this study, we evaluated the redox state of various organs in mice following radon inhalation at concentrations of 2 or 20 kBq/m3 for 1, 3 or 10 days. Scatter plots were used to evaluate the relationship between antioxidative function and oxidative stress by principal component analysis (PCA) of data from control mice subjected to sham inhalation. The results of principal component (PC) 1 showed that the liver and kidney had high antioxidant capacity; the results of PC2 showed that the brain, pancreas and stomach had low antioxidant capacities and low lipid peroxide (LPO) content, whereas the lungs, heart, small intestine and large intestine had high LPO content but low antioxidant capacities. Furthermore, using the PCA of each obtained cluster, we observed altered correlation coefficients related to glutathione, hydrogen peroxide and LPO for all groups following radon inhalation. Correlation coefficients related to superoxide dismutase in organs with a low antioxidant capacity were also changed. These findings suggested that radon inhalation could alter the redox state in organs; however, its characteristics were dependent on the total antioxidant capacity of the organs as well as the radon concentration and inhalation time. The insights obtained from this study could be useful for developing therapeutic strategies targeting individual organs.

Confirmation of efficacy, elucidation of mechanism, and new search for indications of radon therapy

Indications of radon therapy include various diseases related to respiratory, painful, digestive, chronic degenerative, senile, etc. derived from reactive oxygen species, but most are based on empirical prescriptions. For this reason, we have evaluated the relation between the biological response caused by radon and the tissue/organ absorbed dose more quantitatively, and have promoted the elucidation of mechanisms related to the indication and searching newly. As a result, as a mechanism, a series of moderate physiological stimulative effects accompanying a small amount of oxidative stress by radon inhalation are being elucidated. That is, hyperfunction of anti-oxidation/immune regulation/damage repair, promotion of anti-inflammation/circulating metabolism/hormone secretion, induction of apoptosis/heat shock protein, etc. Also, new indications include inflammatory/neuropathic pain, hepatic/renal injury, colitis, type 1 diabetes, complication kidney injury, hyperuricemia, transient cerebral ischemia, and inflammatory edema. Furthermore, we examined the combined antioxidant effect of radon inhalation and antioxidants or therapeutic agents. As a result, it was clear that any combination treatment could enhance the suppression effect of disease. It can be expected that radon therapy can be used effectively by applying it in addition to usual treatment, since reduction in its dosage can also be expected by concomitant use for drugs with strong side effects.

Cohousing-mediated microbiota transfer from milk bioactive components-dosed mice ameliorate colitis by remodeling colonic mucus barrier and lamina propria macrophages

Human milk oligosaccharides (HMOs) and milk fat globule membrane (MFGM) are highly abundant in breast milk, and have been shown to exhibit potent immunomodulatory effects. Yet, their role in the gut microbiota modulation in relation to colitis remains understudied. Since the mixtures of fructo-oligosaccharides (FOS) and galacto-oligosaccharides (GOS) perfectly mimic the properties and functions of HMOs, the combination of MFGM, FOS, and GOS (CMFG) has therefore been developed and used in this study. Here, CMFG were pre-fed to mice for three weeks to investigate its preventive effect on dextran sodium sulfate (DSS) induced colitis. Moreover, CMFG-treated and vehicle-treated mice were cohoused to further elucidate the preventive role of the gut microbiota transfer in colitis. At the end of the study, 16S rDNA gene amplicon sequencing, short-chain fatty acids (SCFAs) profiling, transcriptome sequencing, histological analysis, immunofluorescence staining and flow cytometry analysis were conducted. Our results showed that CMFG pre-supplementation alleviated DSS-induced colitis as evidenced by decreased disease activity index (DAI) score, reduced body weight loss, increased colon length and mucin secretion, and ameliorated intestinal damage. Moreover, CMFG reduced macrophages in the colon, resulting in decreased levels of IL-1β, IL-6, IL-8, TNF-α, and MPO in the colon and circulation. Furthermore, CMFG altered the gut microbiota composition and promoted SCFAs production in DSS-induced colitis. Markedly, the cohousing study revealed that transfer of gut microbiota from CMFG-treated mice largely improved the DSS-induced colitis as evidenced by reduced intestinal damage and decreased macrophages infiltration in the colon. Moreover, transfer of the gut microbiota from CMFG-treated mice protected against DSS-induced gut microbiota dysbiosis and promotes SCFAs production, which showed to be associated with colitis amelioration. Collectively, these findings demonstrate the beneficial role of CMFG in the gastrointestinal diseases, and further provide evidence for the rational design of effective prophylactic functional diets in both animals and humans.

Radon Exposure-Therapeutic Effect and Cancer Risk

Largely unnoticed, all life on earth is constantly exposed to low levels of ionizing radiation. Radon, an imperceptible natural occurring radioactive noble gas, contributes as the largest single fraction to radiation exposure from natural sources. For that reason, radon represents a major issue for radiation protection. Nevertheless, radon is also applied for the therapy of inflammatory and degenerative diseases in galleries and spas to many thousand patients a year. In either case, chronic environmental exposure or therapy, the effect of radon on the organism exposed is still under investigation at all levels of interaction. This includes the physical stage of diffusion and energy deposition by radioactive decay of radon and its progeny and the biological stage of initiating and propagating a physiologic response or inducing cancer after chronic exposure. The purpose of this manuscript is to comprehensively review the current knowledge of radon and its progeny on physical background, associated cancer risk and potential therapeutic effects.

Fish Oil, Cannabidiol and the Gut Microbiota: An Investigation in a Murine Model of Colitis

Inflammatory bowel disorders can be associated with alterations in gut microbiota (dysbiosis) and behavioral disturbances. In experimental colitis, administration of fish oil (FO) or cannabinoids, such as cannabidiol (CBD), reduce inflammation. We investigated the effect of combined FO/CBD administration on inflammation and dysbiosis in the dextran sulphate sodium (DSS) model of mouse colitis, which also causes behavioral disturbances. Colitis was induced in CD1 mice by 4% w/v DSS in drinking water for five consecutive days followed by normal drinking water. FO (20–75 mg/mouse) was administered once a day starting two days after DSS, whereas CBD (0.3–30 mg/kg), alone or after FO administration, was administered once a day starting 3 days after DSS, until day 8 (d8) or day 14 (d14). Inflammation was assessed at d8 and d14 (resolution phase; RP) by measuring the Disease Activity Index (DAI) score, change in body weight, colon weight/length ratio, myeloperoxidase activity and colonic interleukin (IL)-1β (IL-1β), IL-10, and IL-6 concentrations. Intestinal permeability was measured with the fluorescein isothiocyanate-dextran. Behavioral tests (novel object recognition (NOR) and light/dark box test) were performed at d8. Fecal microbiota composition was determined by ribosomal 16S DNA sequencing of faecal pellets at d8 and d14. DSS-induced inflammation was stronger at d8 and accompanied by anxiety-like behavior and impaired recognition memory. FO (35, 50, 75 mg/mouse) alone reduced inflammation at d8, whereas CBD alone produced no effect at any of the doses tested; however, when CBD (3, 10 mg/kg) was co-administered with FO (75 mg/mouse) inflammation was attenuated. FO (20 mg/mouse) and CBD (1 mg/kg) were ineffective when given alone, but when co-administered reduced all inflammatory markers and the increased intestinal permeability at both d8 and d14, but not the behavioral impairments. FO, CBD, and their combination affected gut bacteria taxa that were not affected by DSS per se. Akkermansia muciniphila, a species suggested to afford anti-inflammatory action in colitis, was increased by DSS only at d14, but its levels were significantly elevated by all treatments at d8. FO and CBD co-administered at per se ineffective doses reduce colon inflammation, in a manner potentially strengthened by their independent elevation of Akkermansia muciniphila.

CU06-1004 Alleviates Experimental Colitis by Modulating Colonic Vessel Dysfunction

Inflammatory bowel disease is an autoimmune disease that causes chronic inflammation of the gastrointestinal tract. Endothelial dysfunction, defined by a reduced endothelial barrier and an increase in the expression of adhesion molecules, is part of the pathology of inflammatory bowel disease. In this study, we assessed the therapeutic effect of CU06-1004, an endothelial dysfunction blocker that reduces vascular hyperpermeability and inflammation in a mouse model of colitis. Acute colitis was induced in mice using 3% (w/v) dextran sodium sulfate added to their drinking water for 7 days. Twenty-four hours after the addition of dextran sodium sulfate, either mesalazine or CU06-1004 was administered orally each day. Administration of CU06-1004 significantly reduced the clinical manifestations (weight loss, diarrhea, and bloody stool) and histological changes (epithelium loss, inflammatory cell infiltration, and crypt destruction) induced by dextran sodium sulfate. Proinflammatory cytokines were also reduced, indicating that inflammation was ameliorated. From a vascular perspective, CU06-1004 reduced interrupted and tortuous vessels, enhanced junction protein expression, and reduced inflammatory adhesion molecules, indicating a broad improvement of endothelial dysfunction. Endothelial protection induced epithelial barrier restoration and decreased epithelial inflammation. Blocking endothelial dysfunction with CU06-1004 significantly ameliorated the progression of inflammatory bowel disease. Therefore, CU06-1004 may represent a potential therapeutic agent for the treatment of inflammatory bowel disease as well as other inflammatory diseases.

Comparison of antioxidative effects between radon and thoron inhalation in mouse organs

Radon therapy has been traditionally performed globally for oxidative stress-related diseases. Many researchers have studied the beneficial effects of radon exposure in living organisms. However, the effects of thoron, a radioisotope of radon, have not been fully examined. In this study, we aimed to compare the biological effects of radon and thoron inhalation on mouse organs with a focus on oxidative stress. Male BALB/c mice were randomly divided into 15 groups: sham inhalation, radon inhalation at a dose of 500 Bq/m³ or 2000 Bq/m³, and thoron inhalation at a dose of 500 Bq/m³ or 2000 Bq/m³ were carried out. Immediately after inhalation, mouse tissues were excised for biochemical assays. The results showed a significant increase in superoxide dismutase and total glutathione, and a significant decrease in lipid peroxide following thoron inhalation under several conditions. Additionally, similar effects were observed for different doses and inhalation times between radon and thoron. Our results suggest that thoron inhalation also exerts antioxidative effects against oxidative stress in organs. However, the inhalation conditions should be carefully analyzed because of the differences in physical characteristics between radon and thoron.

Perturbation of the lipid metabolism and intestinal inflammation in growing pigs with low birth weight is associated with the alterations of gut microbiota

Low birth weight (LBW) is accompanied by metabolic dysfunction, chronic inflammation and gut microbiota perturbation in piglets during early life. Regulating gut microbiota structure can indirectly or directly affect gut health and the host's metabolism. However, whether gut microbiota dysbiosis impact lipid metabolism and inflammation progression in the LBW pigs later in life is unclear. In the present study, we investigated the role of gut microbiota on homeostasis in organisms using young pigs as a model. The plasma concentrations of High-density lipoproteins (HDLC) and pro-inflammatory cytokines such as Interleukin 6 (IL-6), Tumor necrosis factor alpha (TNF-α) and Interleukin 18 (IL-18) were increased in LBW pigs. The bacterial composition was modified dramatically in LBW group in association with an increase in propionate, butyrate and Short-chain fatty acids (SCFAs) in the ileal digesta. LBW impaired intestine results in damaged Fatty acid-binding protein 1 (FABP2) and Fatty acid-binding protein 4 (FABP4) expressions, and the inhibition of Free fatty acid receptor 1 (FFAR1), Free fatty acid receptor 2 (FFAR2) and G protein-coupled receptor 119 (GPR119) expressions, causing inefficient SCFAs absorption. Meanwhile, the physical barrier and chemical barrier related to functional gene expressions of Occludin, Claudin-1, Mucin 1 (MUC1) and Mucin 2 (MUC2) in both ileum and colon were decreased in the LBW pigs. The genera of Blautia, Bifidobacterium, Subdoligranulum and Coprococcus 3 in the ileum were correlated positively with lipid metabolic dysfunction and pro-inflammatory response in LBW pigs. Collectively, the gut microbiota is critical for perturbation of lipid metabolism and inflammatory progression in LBW pigs, which suggests the interventions for modulating bacterial communities may be therapeutically beneficial for metabolic diseases and chronic inflammation.

Decitabine attenuates dextran sodium sulfate‑induced ulcerative colitis through regulation of immune regulatory cells and intestinal barrier

To investigate the effect of decitabine on the regulation of intestinal barrier function in mice with inflammatory bowel disease, an experimental model of colitis was established via drinking water with dextran sulfate sodium (DSS). Hematoxylin and eosin staining was used to observe the pathological changes of the colon. Cytokine production was measured by an ELISA assay. Flow cytometry was used to measure the level of regulatory T cells. Immunofluorescence, immunohistochemistry and western blot analyses detected the protein expression and distribution in colon tissue. Following the administration of decitabine, the symptoms of intestinal inflammation in the mice were significantly relieved; the expression of IL-17 was decreased, and the levels of TGF-β and IL-10 were increased. In addition, the induction of forkhead box P3 (Foxp3) in naive T cells increased the proportion of CD4⁺ Foxp3⁺ T cells in CD4⁺ T cells. Furthermore, decitabine increased the levels of zonular occludens-1 and occludin, and inhibited the phosphorylation of ERK1/2, JNK and p38. In conclusion, the present study suggested that decitabine could alleviate DSS-induced impaired colon barrier and the weight loss, mucus and bloody stools in mice by releasing the inhibitory factor IL-10, reducing the pro-inflammatory factor IL-17, activating CD4⁺ Foxp3⁺ T cells and inhibiting the activation of the MAPK pathway.

Membrane proteomic analysis reveals the intestinal development is deteriorated by intrauterine growth restriction in piglets

The alterations of the intestinal proteome were observed in intrauterine growth restriction (IUGR) piglets during early life by gel-based approaches. Nevertheless, how IUGR affects the intestinal membrane proteome during neonatal development remains unclear. Here, we applied the iTRAQ-based proteomics technology and biochemical analysis to investigate the impact of IUGR on the membrane proteome of the jejunal mucosa in the piglets. Three hundred sixty-one membrane proteins were screened by functional prediction. Among them, eight, five, and one differentially expressed membrane proteins were identified between IUGR and NBW piglets at day 0, day 7, and day 21 after birth, respectively. Differentially expressed membrane proteins (DEMPs) including F1SBL3, F1RRW8, F1S539, F1S2Z2, F1RIR2, F1RUF2 I3LP60, Q2EN79, and F1SIH8 were reduced while the relative abundance of I3L6A2, F1SCJ1, F1RI18, I3LRJ7, and F1RNN0 were increased in IUGR piglets than NBW piglets. From the aspects of function, F1RRW8, F1S539, F1S2Z2, and F1RIR2 are mainly associated with D2 dopamine receptor binding, transmembrane transport of small molecules, signal transduction, and translocation of GLUT4, respectively, and F1SIH8, I3LRJ7, and F1RNN0 are related to autophagy, metabolism of vitamins, and intracellular protein transport. Additionally, IUGR decreased the level of proteins (F1RRW8, Q2EN79, and F1RI18) that are involved in response to oxidative stress.

Colonic Epithelial Surfactant Protein D Expression Correlates with Inflammation in Clinical Colonic Inflammatory Bowel Disease

BACKGROUND

Inflammatory bowel diseases (IBD) are chronic disorders of the gastrointestinal tract. Surfactant protein D (SP-D) is expressed in the intestinal epithelium and is essential for innate host defense and regulation of inflammatory responses. Genetic variations of SP-D are associated with IBD, but the effects of SP-D in clinical disease development have not been clarified. We hypothesized that colonic epithelial SP-D expression is increased in parallel with intestinal inflammation with the capacity to dampen deleterious effects.

METHODS

Surgical specimens from IBD patients including Crohn's disease (n = 9) and ulcerative colitis (n = 18) were scored for expression of SP-D and inflammatory activity. Cohoused Sftpd+/+ and Sftpd-/- mouse littermates were subjected to dextran sodium sulfate (DSS) for 7 days to induce colitis. Colonic tissue was scored for histologic damage and analyzed for inflammatory markers and expression of SP-D.

RESULTS

Surgical specimens from IBD patients showed a strong positive correlation between immunoscore for SP-D and inflammatory activity (R2 = 0.78, P < 0.0001). In mice, colonic epithelial SP-D expression was very low, and DSS-induced colitis was unaffected by SP-D deficiency, although DSS induced transcription of colonic SP-D to a mild degree.

CONCLUSIONS

A strong positive correlation between inflammatory activity and epithelial expression of SP-D was observed in surgical specimens from IBD patients supporting a role for SP-D in clinical disease. The in vivo study was inconclusive due to very low intestinal SP-D expression in the mouse. Further studies are warranted to support that increased SP-D expression in the human colonic epithelium is protective against intestinal inflammation.

Milk Fat Globule Membrane Supplementation Promotes Neonatal Growth and Alleviates Inflammation in Low-Birth-Weight Mice Treated with Lipopolysaccharide

Impaired intestinal mucosal integrity and immunity are frequently observed in low-birth-weight (LBW) animals, which lead to inadequate growth and high neonatal mortality. However, the mechanisms of intestinal dysfunction in LBW animals are still unclear. Milk fat globule membrane (MFGM), a protein-lipid complex surrounding the fat globules in milk, has many healthful benefits for animals. Therefore, this study was conducted to explore the effect of MFGM supplementation on intestinal injury and inflammation in LBW mouse pups while being challenged with lipopolysaccharide (LPS). C57BL/6J LBW female neonatal mice were fed on breast milk and divided into four groups, including two normal diet groups (ND; CON group and LPS group) and the diet supplemented with two dosages of MFGM, namely, MFGM100 (ND plus MFGM at 100 mg/kg BW) and MFGM200 (ND plus MFGM at 200 mg/kg BW) from postnatal day (PND) 4 to PND 21. At PND21, pups from the LPS group, MFGM100 group, and MFGM200 group were injected intraperitoneally with LPS while the pups from the CON group were injected with equivalent volume of sterile saline. After 4 h of LPS administration, all pups were slaughtered and then the plasma, mid-ileum, and mid-colon tissue samples were collected. Our results showed that MFGM supplementation promoted the body weight from PND16 to PND21 and attenuated intestinal inflammation manifested by reduced histological damage, decreased secretion of TNF-α, IL-6, IFN-γ, and IL-1β, and improved oxidative stress characterized by increased SOD activity and decreased secretion of MDA. Expression of tight junction proteins (ZO-1, occludin, and claudin-1), MUC1, and MUC2 was increased in MFGM presupplemented groups compared to the LPS-challenged mice with normal diet. Meanwhile, the expression of proinflammatory cytokines and TLRs was decreased by MFGM presupplementation. Collectively, MFGM is a critical nutrient with an ability to improve the growth performance of LBW mouse pups, especially during the LPS challenge, by promoting the intestinal epithelial integrity and inhibiting inflammation through activating of TLR2 and TLR4 signals.

Chemopreventive Activity of Red Ginseng Oil in a Mouse Model of Azoxymethane/Dextran Sulfate Sodium-Induced Inflammation-Associated Colon Carcinogenesis

Our previous studies have demonstrated antioxidant and cytoprotective properties of red ginseng oil (RGO). However, the role of RGO in models of intestinal inflammation has not been elucidated. In this study, we evaluated the chemopreventive effect of RGO in a mouse model of azoxymethane/dextran sulfate sodium (AOM/DSS)-induced colitis and explored its underlying mechanisms. Male C57BL/6 mice were intraperitoneally injected with a single dose of AOM (10 mg/kg), followed by 1.5% DSS in drinking water for 7 days to produce colon carcinogenesis. RGO at 10 or 100 mg/kg was orally given for 17 weeks. RGO supplementation reduced the plasma nitric oxide (NO) concentration as well as lipid peroxidation and inhibited the production of proinflammatory factors such as inducible NO synthase, cyclooxygenase-2, interleukin 1β, IL-6, and tumor necrosis factor-α in the mouse colitis tissue. Increased phosphorylation levels of p65 and IκB by AOM/DSS exposure were attenuated by the presence of RGO. In addition, RGO supplementation induced the activity of primary antioxidant enzymes such as superoxide dismutase and catalase as well as the expression of nuclear factor erythroid 2-related factor 2-mediated antioxidant enzyme hemeoxygenase-1 in the colons of AOM/DSS-treated mice. These findings indicate that RGO may be a potent natural chemopreventive agent for ameliorating inflammatory bowel diseases.

Milk phospholipids ameliorate mouse colitis associated with colonic goblet cell depletion via the Notch pathway

Milk phospholipids attenuated the severity of DSS-induced mouse colitis and prevented the depletion of colonic goblet cells through balancing the over-activated Notch pathway mediated by colonic myofibroblasts.

Intestinal barrier dysfunction orchestrates the onset of inflammatory host-microbiome cross-talk in a human gut inflammation-on-a-chip

The initiation of intestinal inflammation involves complex intercellular cross-talk of inflammatory cells, including the epithelial and immune cells, and the gut microbiome. This multicellular complexity has hampered the identification of the trigger that orchestrates the onset of intestinal inflammation. To identify the initiator of inflammatory host-microbiome cross-talk, we leveraged a pathomimetic "gut inflammation-on-a-chip" undergoing physiological flow and motions that recapitulates the pathophysiology of dextran sodium sulfate (DSS)-induced inflammation in murine models. DSS treatment significantly impaired, without cytotoxic damage, epithelial barrier integrity, villous microarchitecture, and mucus production, which were rapidly recovered after cessation of DSS treatment. We found that the direct contact of DSS-sensitized epithelium and immune cells elevates oxidative stress, in which the luminal microbial stimulation elicited the production of inflammatory cytokines and immune cell recruitment. In contrast, an intact intestinal barrier successfully suppressed oxidative stress and inflammatory cytokine production against the physiological level of lipopolysaccharide or nonpathogenic Escherichia coli in the presence of immune elements. Probiotic treatment effectively reduced the oxidative stress, but it failed to ameliorate the epithelial barrier dysfunction and proinflammatory response when the probiotic administration happened after the DSS-induced barrier disruption. Maintenance of epithelial barrier function was necessary and sufficient to control the physiological oxidative stress and proinflammatory cascades, suggesting that "good fences make good neighbors." Thus, the modular gut inflammation-on-a-chip identifies the mechanistic contribution of barrier dysfunction mediated by intercellular host-microbiome cross-talk to the onset of intestinal inflammation.

Allyl Isothiocyanate Ameliorates Dextran Sodium Sulfate-Induced Colitis in Mouse by Enhancing Tight Junction and Mucin Expression

Inflammatory bowel disease (IBD) is characterized by chronic or recurrent inflammation of the gastrointestinal tract. Even though the current strategies to treat IBD include anti-inflammatory drugs and immune modulators, these treatments have side-effects. New strategies are, therefore, required to overcome the limitations of the therapies. In this study, we investigated the anti-colitic effects of allyl isothiocyanate (AITC), which is an active ingredient present in Wasabia japonica. The DSS-induced colitis model in the mouse was used to mimic human IBD and we observed that AITC treatment ameliorated the severity of colitis. We further studied the mechanism involved to ameliorate the colitis. To investigate the involvement of AITC on the intestinal barrier function, the effect on the intercellular tight junction was evaluated in the Caco-2 cell line while mucin expression was assessed in the LS174T cell line. AITC positively regulated tight junction proteins and mucin 2 (MUC2) against DSS-induced damage or depletion. Our data of in vivo studies were also consistent with the in vitro results. Furthermore, we observed that MUC2 increased by AITC is dependent on ERK signaling. In conclusion, we propose that AITC can be considered as a new strategy for treating IBD by modulating tight junction proteins and mucin.

Methionine restriction on oxidative stress and immune response in dss-induced colitis mice

A strong correlation exists between inflammatory bowel disease (IBD) and oxidative stress involving alterations of several key signaling pathways. It is known that methionine promotes reactive oxygen species (ROS) production; we therefore hypothesize that a methionine restriction diet would reduce ROS production, inflammatory responses, and the course of IBD. We generated a murine colitis model by dextran sodium sulfate (DSS) treatment and tested the effects of the methionine restriction diet. Forty-eight mice were randomly divided into four groups of equal size, which included a control (CON) group, an MR (methionine restriction diet) group, a DSS treated group and an MR-DSS treated group. Mice in the first two groups had unrestricted access to water for one week. Mice in the two DSS-treated groups had unrestricted access to 5% DSS solution supplied in the drinking water for the same period. Mice in the CON and DSS groups were given a basal diet, whereas mice in the MR-DSS and MR groups were fed a 0.14% MR diet. We found that DSS reduced daily weight gain, suppressed antioxidant enzyme expression, increased histopathology scores and activated NF-κB and nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) signaling. We also showed that the MR diet upregulated catalase (CAT), superoxide dismutase (SOD), and glutathione peroxidase (GPx) activities, decreased myeloperoxidase (MPO), TNF-α and IL-1β, and reversed activation of the NF-κB signaling pathway in MR-DSS mice. Taken together, our results imply that the MR diet may be considered as an adjuvant in IBD therapeutics.

Protective effects of hot spring water drinking and radon inhalation on ethanol-induced gastric mucosal injury in mice

Radon therapy using radon (222Rn) gas is classified into two types of treatment: inhalation of radon gas and drinking water containing radon. Although short- or long-term intake of spa water is effective in increasing gastric mucosal blood flow, and spa water therapy is useful for treating chronic gastritis and gastric ulcer, the underlying mechanisms for and precise effects of radon protection against mucosal injury are unclear. In the present study, we examined the protective effects of hot spring water drinking and radon inhalation on ethanol-induced gastric mucosal injury in mice. Mice inhaled radon at a concentration of 2000 Bq/m3 for 24 h or were provided with hot spring water for 2 weeks. The activity density of 222Rn ranged from 663 Bq/l (start point of supplying) to 100 Bq/l (end point of supplying). Mice were then orally administered ethanol at three concentrations. The ulcer index (UI), an indicator of mucosal injury, increased in response to the administration of ethanol; however, treatment with either radon inhalation or hot spring water inhibited the elevation in the UI due to ethanol. Although no significant differences in antioxidative enzymes were observed between the radon-treated groups and the non-treated control groups, lipid peroxide levels were significantly lower in the stomachs of mice pre-treated with radon or hot spring water. These results suggest that hot spring water drinking and radon inhalation inhibit ethanol-induced gastric mucosal injury.

Umbilical cord-derived mesenchymal stem cell extracts reduce colitis in mice by re-polarizing intestinal macrophages

Human umbilical cord mesenchymal stem cells (hUC-MSCs), originating in Wharton’s jelly, are multipotent stem cells that home to damaged tissues and can modulate the immune system. We examined whether administering extracts of MSCs (MSC-Ex) instead of MSCs could augment the beneficial effects of MSC therapy by overcoming the low homing efficiency of MSCs systemically administered in inflammatory bowel diseases (IBD). Dextran sodium sulfate-induced colitis model was established in C57BL/6 mice, and MSC-Ex was administered intraperitoneally. MSC-Ex reduced colitis, disease activity index (DAI), and histological colitis scores, and increased the body weight. Treatment with MSC-Ex completely blocked the induction of inflammatory cytokines, which were strongly detected in mice with colitis. MSC-Ex shifted the macrophage functional phenotype from M1 to M2 by decreasing the levels of MCP1, CXCL9, and iNOS, but increasing the levels of IL-10, LIGHT, CCL1, and Arg-1. MSC-Ex recovered the destruction of the epithelial barrier in the differentiated Caco-2 cells in vitro. Treatment with MSC-Ex was more potent than that with MSC in reducing DAI, the histological score, and nitrite levels. These data strongly support that MSC-Ex treatment can be a potent approach to overcome severe refractory IBD.

Dietary Supplementation of Fermented Rice Bran Effectively Alleviates Dextran Sodium Sulfate-Induced Colitis in Mice

Rice bran (RB) is a major by-product of rice polishing and a rich source of bioactive compounds. Here, we investigated the anti-colitis effect of diet supplementation with fermented rice bran (FRB) in a murine model of ulcerative colitis. FRB was prepared by dual fermentation of RB using fungi and lactic acid bacteria. Colitis was induced in C57Bl/6N male mice (n = 8/group) by dextran sodium sulfate (DSS). Body weight change, disease activity index (DAI), histopathology score, tissue myeloperoxidase (MPO) activity, cytokine and chemokine transcript levels, and the production of short-chain fatty acids (SCFAs) and mucin in the colonic tissue were monitored. Based on histopathology scores, DSS induced severe mucosal inflammation, with an increased loss of crypts, and inflammatory cell infiltration in the control and RB groups, but not in the FRB group. MPO activity, thiobarbituric acid-reactive substance levels, and pro-inflammatory cytokine transcript (Tnf-α, Il-1β, Il-6, and Il-17) levels were significantly higher in the control and RB groups than in the FRB group. Thus, dietary FRB attenuated intestinal inflammation owing to elevated SCFAs and tryptamine production, which might regulate tight junction barrier integrity and intestinal homeostasis. These results suggest that FRB could comprise an effective potential preventive agent for ulcerative colitis.

Dietary tryptophan alleviates dextran sodium sulfate-induced colitis through aryl hydrocarbon receptor in mice

Ulcerative colitis is the typical progression of chronic inflammatory bowel disease. Amino acids, particularly tryptophan, have been reported to exert a protective effect against colitis induced by dextran sodium sulfate (DSS), but the precise underlying mechanisms remain incompletely clarified. Tryptophan metabolites are recognized to function as endogenous ligands for aryl hydrocarbon receptor (Ahr), which is a critical regulator of inflammation and immunity. Thus, we conducted this study to investigate whether dietary tryptophan supplementation protects against DSS-induced colitis by acting through Ahr. Female wild-type (WT) and Ahr-deficient (knockout; KO) mice (10-12 weeks old) were divided into four groups and fed either a control or 0.5% tryptophan diet. The tryptophan diet ameliorated DSS-induced colitis symptoms and severity in WT mice but not in KO mice, and the diet reduced the mRNA expression of Il-6, Tnfα, Il-1β and the chemokines Ccl2, Cxcl1 and Cxcl2 in the WT groups. Furthermore, Il-22 and Stat3 mRNA expression in the colon was elevated in WT mice fed with the tryptophan diet, which mainly protected epithelial layer integrity, and Ahr also modulated immune homeostasis by regulating Foxp3 and Il-17 mRNA expression. These data suggest that tryptophan-containing diet might ameliorate DSS-induced acute colitis and regulate epithelial homeostasis through Ahr. Thus, tryptophan could serve as a promising preventive agent in the treatment of ulcerative colitis.

Induction of Indoleamine 2,3-dioxygenase by Pre-treatment with Poly(I:C) May Enhance the Efficacy of MSC Treatment in DSS-induced Colitis

Mesenchymal stem cells (MSCs) have been used experimentally for treating inflammatory disorders, partly owing to their immunosuppressive properties. The goal of the study was to determine whether TLR ligands can enhance the therapeutic efficacy of bone marrow-derived MSCs for the treatment of inflammatory bowel disease. Mice (C57BL6) were administered with 4% dextran sulfate sodium (DSS) in drinking water for 7 days and injected with MSCs on days 1 and 3 following DSS ingestion. Our results demonstrated that among various TLR ligands, MSCs treated with polyinosinic-polycytidylic acid [poly(I:C)], which is a TLR3 ligand, more profoundly induced IDO, which is a therapeutically relevant immunosuppressive factor, without any observable phenotype change in vitro. The poly(I:C)-treated MSCs attenuated the pathologic severity of DSS-induced murine colitis when injected i.p. but not i.v. In summary, preconditioning MSCs with poly(I:C) might improve their efficacy in treating DSS-induced colitis, and this effect at least partly depends on the enhancement of their immunosuppressive activity through increasing their production of IDO.

Fermented Pueraria Lobata extract ameliorates dextran sulfate sodium-induced colitis by reducing pro-inflammatory cytokines and recovering intestinal barrier function

Inflammatory bowel disease is a chronic inflammatory disorder occurring in the gastrointestinal track. However, the efficacy of current therapeutic strategies has been limited and accompanied by side effects. In order to eliminate the limitations, herbal medicines have recently been developed for treatment of IBD. Peuraria Lobata (Peuraria L.) is one of the traditional herbal medicines that have anti-inflammatory effects. Bioavailability of Peuraria L., which is rich in isoflavones, is lower than that of their fermented forms. In this study, we generated fermented Peuraria L. extracts (fPue) and investigated the role of fPue in inflammation and intestinal barrier function in vitro and in vivo. As the mice or intestinal epithelial cells were treated with DSS/fPue, mRNA expression of pro-inflammatory cytokines was reduced and the architecture and expression of tight junction proteins were recovered, compared to the DSS-treated group. In summary, fPue treatment resulted in amelioration of DSS-induced inflammation in the colon, and the disrupted intestinal barrier was recovered as the expression and architecture of tight junction proteins were retrieved. These results suggest that use of fPue could be a new therapeutic strategy for treatment of IBD.

Garlic oil inhibits dextran sodium sulfate-induced ulcerative colitis in rats

AIMS

Garlic oil (GO) is used for centuries in folk medicine as a therapy for many diseases including inflammatory disorders. Recently, it has exhibited potent anti-oxidant, anti-inflammatory and immunomodulatory effects. Consequently, we evaluated the possible protective effect of GO in a rat model of colitis, induced by dextran sulfate sodium (DSS).

MAIN METHODS

Colitis induced by allowing rats a free access to drinking water containing 5% DSS for 7 days, from day 1 to day 7. GO was administered orally in doses of 25, 50 and 100mg/kg/day. Mesalazine used as a standard medication in a dose of 15 mg/kg/day. All animals fasted for 2h, 1h before and 1h after giving the treatment, which introduced daily for 7 days, from day 1 to day 7, at 10:00 to 11:00 A.M. Animal body, and colonic weights, colonic myeloperoxidase (MPO), and superoxide dismutase (SOD) activities, colonic reduced-glutathione (GSH), malondialdehyde (MDA), tumor necrosis factor-α (TNF-α), interleukin (IL)-1β, and IL-10 levels, macroscopic and microscopic changes of colonic tissues were evaluated.

KEY FINDINGS

GO treatment significantly suppressed the elevated colonic weight, MPO activity, MDA, TNF-α and IL-1β levels. However, it potentiated the decrease body weight, colonic SOD activity, GSH and IL-10 levels. Moreover, it ameliorated the marked macroscopic and microscopic changes of colonic mucosa in a dose dependent manner.

SIGNIFICANCE

Garlic oil inhibits DSS-induced colitis in rats may be through its anti-oxidant, anti-inflammatory and immunomodulatory properties. Therefore, GO could be a promising protective agent recommended for UC patients.

Pyrrolidine Dithiocarbamate Inhibits NF-KappaB Activation and Upregulates the Expression of Gpx1, Gpx4, Occludin, and ZO-1 in DSS-Induced Colitis

Inflammatory bowel disease (IBD) correlates with oxidative stress, inflammation, and alteration in several signal pathways, including nuclear transcription factor-kappaB (NF-κB). Pyrrolidine dithiocarbamate (PDTC), an inhibitor of NF-κB, has been widely demonstrated to exhibit an antioxidant and anti-inflammatory function. This study aimed to test the hypothesis that NF-κB inhibitor PDTC confers a beneficial role in a colitis model induced by dextran sodium sulfate (DSS) in mouse. The results showed that DSS decreased daily weight gain, induced colonic inflammation, suppressed the expression of antioxidant enzymes and tight junctions, and activated NF-κB and nuclear factor erythroid 2-related factor 2/Kelch-like ECH-associated protein 1 (Nrf2/Keap1) signaling pathways. PDTC significantly upregulated (P < 0.05) Gpx1, Gpx4, occludin, and ZO-1 expressions in the DSS-induced colitis model. Meanwhile, PDTC reversed (P < 0.05) the activation of NF-κB signal pathway caused by DSS treatment. In conclusion, PDTC could serve as an adjuvant therapy for the patient with IBD.

RasGRP1 opposes proliferative EGFR-SOS1-Ras signals and restricts intestinal epithelial cell growth

The character of EGFR signals can influence cell fate but mechanistic insights into intestinal EGFR-Ras signalling are limited. Here we show that two distinct Ras nucleotide exchange factors, RasGRP1 and SOS1, lie downstream of EGFR but act in functional opposition. RasGRP1 is expressed in intestinal crypts where it restricts epithelial growth. High RasGRP1 expression in colorectal cancer (CRC) patient samples correlates with a better clinical outcome. Biochemically, we find that RasGRP1 creates a negative feedback loop that limits proliferative EGFR-SOS1-Ras signals in CRC cells. Genetic Rasgrp1 depletion from mice with either an activating mutation in KRas or with aberrant Wnt signalling due to a mutation in Apc resulted in both cases in exacerbated Ras-ERK signalling and cell proliferation. The unexpected opposing cell biological effects of EGFR-RasGRP1 and EGFR-SOS1 signals in the same cell shed light on the intricacy of EGFR-Ras signalling in normal epithelium and carcinoma.

Macromolecular glucocorticoid prodrug improves the treatment of dextran sulfate sodium-induced mice ulcerative colitis

A macromolecular prodrug (P-Dex) of dexamethasone (Dex) was developed to improve the treatment of inflammatory bowel disease (IBD). Colonic inflammation was induced by feeding mice with dextran sulfate sodium. Mice were treated with daily i.p. injection of free Dex or single i.v. injection of P-Dex, PBS or free polymer. Both P-Dex and free Dex could lower disease activity index and histology scores when compared to the controls. A single injection of P-Dex with 1/4 equivalent Dex dose had a better therapeutic effect than daily free Dex treatment. Mechanism study found that P-Dex could target the inflamed colon, and be retained by epithelial cells and local inflammatory infiltrates, suggesting that the improved efficacy of P-Dex may be attributed to its inflammation targeting, subcellular processing and activation. Collectively, these data support our hypothesis that the development of macromolecular prodrug of glucocorticoid may have the potential to improve the clinical management of IBD.