Colonic epithelial mTORC1 promotes ulcerative colitis through COX-2-mediated Th17 responses

Neohesperidin Dihydrochalcone Ameliorates Experimental Colitis via Anti-Inflammatory, Antioxidative, and Antiapoptosis Effects

Neohesperidin dihydrochalcone (NHDC) is a citrus-originated, seminatural sweetener. There is no investigation concerning the effect of NHDC on ulcerative colitis. The purpose of this study was to determine the therapeutic and protective effects of NHDC in Wistar Albino rats. NHDC was given for 7 days after or before colitis induction. The results showed that NHDC significantly reduced the interleukin-6 (IL-6), interleukin-10 (IL-10), transforming growth factor-β1 (TGF-β1), tumor necrosis factor-α (TNF-α), and interferon-γ (IFN-γ) levels. Catalase levels did not show a significant difference between the groups. NHDC provided a remarkable decrease in the expression levels of cyclooxygenase-2 (COX-2), myeloperoxidase (MPO), malondialdehyde (MDA), 8-hydroxy-2'-deoxyguanosine (8-OHdG), and nuclear factor kappa B (NF-κB). Total antioxidant status (TAS) levels were significantly elevated in NHDC treatment groups, while total oxidant status (TOS) and oxidative stress index (OSI) levels were significantly decreased. NHDC provided remarkable improvement in histological symptoms such as epithelial erosion, edema, mucosal necrosis, inflammatory cell infiltration, and hemorrhage. Also, caspase-3 expression levels were statistically decreased in NHDC treatment groups. The results indicated that NHDC might be a protection or alternative treatment for ulcerative colitis.

Chemopreventive and immunomodulatory effects of phenolic-rich extract of Commiphora leptophloeos against inflammatory bowel disease: Preclinical evidence

ETHNOPHARMACOLOGY RELEVANCE

Commiphora leptophloeos (Mart.) J.B. Gillet (Burseraceae) is a medicinal plant native to Brazil, popularly known as "imburana". Homemade leaf decoction and maceration were used to treat general inflammatory problems in the Brazilian Northeast population. Our previous research confirmed the anti-inflammatory activity of the C. leptophloeos hydroalcoholic leaf extract.

AIM OF THE STUDY

Inflammatory bowel disease (IBD) is a chronic and relapsing inflammatory disorder of the gut with no ideal treatment to maintain the remissive status. This work aimed to characterize the phytochemical composition and physicochemical properties of the C. leptophloeos hydroalcoholic leaf extract and its efficacy in chemopreventive and immunomodulatory responses in inflammatory bowel disease in non-clinical models.

MATERIALS AND METHODS

Mass spectrometry and physicochemical tests determined the phytochemical profile and physicochemical characteristics of the Commiphora leptophloeos (CL) extract. The chemopreventive and immunomodulatory effects of CL extract (50 and 125 μg/mL) were evaluated in vitro in the RAW 264.7 lipopolysaccharide (LPS) induced cell assay and in vivo in the model of intestinal inflammation induced by 2,4-Dinitrobenzenesulfonic acid (DNBS) in mice when they were treated with CL extract by intragastric gavage (i.g.) at doses of 300, 400 and 500 mg/kg.

RESULTS

Phytochemical annotation of CL extract showed a complex phenolic composition, characterized as phenolic acids and flavonoids, and satisfactory physicochemical characteristics. In addition, CL extract maintained the viability of RAW macrophages, reduced ROS and NO production, and negatively regulated COX-2, iNOS, TNF-α, IL-1β, IL-6, and IL-17 (p < 0.05). In the intestinal inflammation model, CL extract was able to downregulate NF-κB p65/COX-2, mTOR, iNOS, IL-17, decrease levels of malondialdehyde and myeloperoxidase and cytokines TNF-α, IL-1β and IL-6 (p < 0.05).

CONCLUSION

Based on these findings, CL extract reduced inflammatory responses by down-regulating pro-inflammatory markers in macrophages induced by LPS and DNBS-induced colitis in mice through NF-κB p65/COX-2 signaling. CL leaf extract requires further investigation as a candidate for treating inflammatory bowel disease.

mTOR promotes an inflammatory response through the HIF1 signaling pathway in ulcerative colitis

The imbalance between T helper cell 17 （Th17）and regulatory T cells (Treg) cells leading to inflammation has an important role in the pathogenesis of ulcerative colitis (UC). Mammalian target of rapamycin (mTOR) can regulate the differentiation of T cells, but the specific pathway leading mTOR to regulate Th17/Treg cells in UC remains unclear. Our aim with this study was to investigate the effects of mTOR overexpression and silencing on the hypoxia inducible factor-1α (HIF-1α) - Th17/Treg signaling pathway. To mimic a human study, we established a colon cancer epithelial cell line (HT-29) co-culture system with human CD4+ T cells, and we treated the cells with TNF-α. We observed the effects of mTOR on the HIF-Th17/Treg signaling pathway to determine whether mTOR is involved in the regulatory mechanism. Under the stimulation of TNF-α, the levels of HIF-1α in CD4+T cells were increased in the HT-29 co-culture with CD4+ T cells, promoting glycolysis, increasing the Th17 proportion, decreasing the Treg proportion, increasing the pro-inflammatory factors levels, and decreasing the anti-inflammatory factors levels. Moreover, after mTOR silencing, the HIF-1α level and cell glycolysis levels decreased, Th17 cell differentiation decreased, the pro-inflammatory factor levels decreased, and the anti-inflammatory factor levels increased. In contrast, mTOR overexpression lead to the opposite results.mTOR promotes inflammation by regulating the HIF signaling pathway during UC, and silencing mTOR may alleviate inflammation. An mTOR inhibitor is a potential therapeutic target for UC treatment.

Unveiling Immunomodulatory Effects of Euglena gracilis in Immunosuppressed Mice: Transcriptome and Pathway Analysis

The immunomodulatory effects of Euglena gracilis (Euglena) and its bioactive component, β-1,3-glucan (paramylon), have been clarified through various studies. However, the detailed mechanisms of the immune regulation remain to be elucidated. This study was designed not only to investigate the immunomodulatory effects but also to determine the genetic mechanisms of Euglena and β-glucan in cyclophosphamide (CCP)-induced immunosuppressed mice. The animals were orally administered saline, Euglena (800 mg/kg B.W.) or β-glucan (400 mg/kg B.W.) for 19 days, and CCP (80 mg/kg B.W.) was subsequently administered to induce immunosuppression in the mice. The mice exhibited significant decreases in body weight, organ weight, and the spleen index. However, there were significant improvements in the spleen weight and the spleen index in CCP-induced mice after the oral administration of Euglena and β-glucan. Transcriptome analysis of the splenocytes revealed immune-related differentially expressed genes (DEGs) regulated in the Euglena- and β-glucantreated groups. Gene ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses indicated that pathways related with interleukin (IL)-17 and cAMP play significant roles in regulating T cells, B cells, and inflammatory cytokines. Additionally, Ptgs2, a major inflammatory factor, was exclusively expressed in the Euglena-treated group, suggesting that Euglena's beneficial components, such as carotenoids, could regulate these genes by influencing immune lymphocytes and inflammatory cytokines in CCP-induced mice. This study validated the immunomodulatory effects of Euglena and highlighted its underlying mechanisms, suggesting a positive contribution to the determination of phenotypes associated with immune-related diseases and the research and development of immunotherapies.

Deciphering the mechanisms of reciprocal regulation or interdependence at the cannabinoid CB1 receptors and cyclooxygenase-2 level: Effects on mood, cognitive implications, and synaptic signaling

The lipid endocannabinoid system refers to endogenous cannabinoids (eCBs), the enzymes involved in their synthesis and metabolism, and the G protein-coupled cannabinoid receptors (GPCRs), CB1, and CB2. CB1 receptors (CB1Rs) are distributed in the brain at presynaptic terminals. Their activation induces inhibition of neurotransmitter release, which are gamma-aminobutyric acid (GABA), glutamate (Glu), dopamine, norepinephrine, serotonin, and acetylcholine. Postsynaptically localized CB1Rs regulate the activity of selected ion channels and N-methyl-D-aspartate receptors (NMDARs). CB2Rs are mainly peripheral and will not be considered here. Anandamide metabolism, mediated by cyclooxygenase-2 (COX-2), generates anandamide-derived prostanoids. In addition, COX-2 regulates the formation of CB1 ligands, which reduce excitatory transmission in the hippocampus (HC). The role of CB1Rs and COX-2 has been described in anxiety, depression, and cognition, among other central nervous system (CNS) disorders, affecting neurotransmission and behavior of the synapses. This review will analyze common pathways, mechanisms, and behavioral effects of manipulation at the CB1Rs/COX-2 level.

Colitis-associated carcinogenesis: crosstalk between tumors, immune cells and gut microbiota

Colorectal cancer (CRC) is the third most common cancer worldwide. One of the main causes of colorectal cancer is inflammatory bowel disease (IBD), which includes ulcerative colitis (UC) and Crohn's disease (CD). Intestinal epithelial cells (IECs), intestinal mesenchymal cells (IMCs), immune cells, and gut microbiota construct the main body of the colon and maintain colon homeostasis. In the development of colitis and colitis-associated carcinogenesis, the damage, disorder or excessive recruitment of different cells such as IECs, IMCs, immune cells and intestinal microbiota play different roles during these processes. This review aims to discuss the various roles of different cells and the crosstalk of these cells in transforming intestinal inflammation to cancer, which provides new therapeutic methods for chemotherapy, targeted therapy, immunotherapy and microbial therapy.

Faecal metabolome and its determinants in inflammatory bowel disease

OBJECTIVE

Inflammatory bowel disease (IBD) is a multifactorial immune-mediated inflammatory disease of the intestine, comprising Crohn's disease and ulcerative colitis. By characterising metabolites in faeces, combined with faecal metagenomics, host genetics and clinical characteristics, we aimed to unravel metabolic alterations in IBD.

DESIGN

We measured 1684 different faecal metabolites and 8 short-chain and branched-chain fatty acids in stool samples of 424 patients with IBD and 255 non-IBD controls. Regression analyses were used to compare concentrations of metabolites between cases and controls and determine the relationship between metabolites and each participant's lifestyle, clinical characteristics and gut microbiota composition. Moreover, genome-wide association analysis was conducted on faecal metabolite levels.

RESULTS

We identified over 300 molecules that were differentially abundant in the faeces of patients with IBD. The ratio between a sphingolipid and L-urobilin could discriminate between IBD and non-IBD samples (AUC=0.85). We found changes in the bile acid pool in patients with dysbiotic microbial communities and a strong association between faecal metabolome and gut microbiota. For example, the abundance of Ruminococcus gnavus was positively associated with tryptamine levels. In addition, we found 158 associations between metabolites and dietary patterns, and polymorphisms near NAT2 strongly associated with coffee metabolism.

CONCLUSION

In this large-scale analysis, we identified alterations in the metabolome of patients with IBD that are independent of commonly overlooked confounders such as diet and surgical history. Considering the influence of the microbiome on faecal metabolites, our results pave the way for future interventions targeting intestinal inflammation.

Hypoxia in the Pathophysiology of Inflammatory Bowel Disease

Inflammatory bowel disease (IBD) is an idiopathic disease of disordered chronic inflammation in the intestines that affects many people across the world. While the disease is still being better characterized, greater progress has been made in understanding the many components that intersect in the disease. Among these components are the many pieces that compose the intestinal epithelial barrier, the various cytokines and immune cells, and the population of microbes that reside in the intestinal lumen. Since their discovery, the hypoxia-inducible factors (HIFs) have been found to play an expansive role in physiology as well as diseases such as inflammation due to their role in oxygen sensing-related gene transcription, and metabolic control. Making use of existing and developing paradigms in the immuno-gastroenterology of IBD, we summarized that hypoxic signaling plays as another component in the status and progression of IBD, which may include possible functions at the origins of inflammatory dysregulation. © 2023 American Physiological Society. Compr Physiol 13:4767-4783, 2023.

miR-146a-5p regulates autophagy and NLRP3 inflammasome activation in epithelial barrier damage in the in vitro cell model of ulcerative colitis through the RNF8/Notch1/mTORC1 pathway

Ulcerative colitis (UC) is a chronic inflammatory disease affecting the colon that can be influenced by microRNAs (miRNAs). This study aims to investigate the impact of miR-146a-5p on lipopolysaccharide (LPS)-induced Caco-2/HT-29 cell autophagy and NLRP3 inflammasome activation and the underlying mechanism, with the aim of identifying potential therapeutic targets. We used LPS to establish Caco-2/HT-29 cell models and measured cell viability by CCK-8. The levels of miR-146a-5p, RNF8, markers of NLRP3 inflammasome activation and autophagy, proteins involved in the Notch1/mTORC1 pathway, and inflammatory factors were assessed by RT-qPCR, Western blot, and ELISA. Intestinal epithelial barrier function was evaluated by measuring transepithelial electrical resistance. Autophagic flux was measured using tandem fluorescent-labeled LC3. miR-146a-5p was highly-expressed in LPS-induced Caco-2/HT-29 cells, and autophagy flux was blocked at the autolysosomal stage after LPS induction. Inhibition of miR-146a-5p suppressed NLRP3 inflammasome activation, reduced intestinal epithelial barrier damage, and facilitated autophagy inhibition in LPS-induced Caco-2/HT-29 cells. The autophagy inhibitor NH4Cl partially nullified the inhibitory effects of miR-146a-5p inhibition on NLRP3 inflammation activation. miR-146a-5p targeted RNF8, and silencing RNF8 partly abrogated the action of miR-146a-5p inhibition on promoting autophagy and inhibiting NLRP3 inflammasome activation. miR-146a-5p inhibition suppressed the Notch1/mTORC1 pathway activation by upregulating RNF8. Inhibition of the Notch1/mTORC1 pathway partially nullified the function of silencing RNF8 on inhibiting autophagy and bolstering NLRP3 inflammasome activation. In conclusion, miR-146a-5p inhibition may be a potential therapeutic approach for UC, as it facilitates autophagy of LPS-stimulated Caco-2/HT-29 cells, inhibits NLRP3 inflammasome activation, and reduces intestinal epithelial barrier damage by upregulating RNF8 and suppressing the Notch1/mTORC1 pathway.

Baitouweng decoction alleviates dextran sulfate sodium-induced ulcerative colitis by suppressing leucine-related mTORC1 signaling and reducing oxidative stress

ETHNOPHARMACOLOGICAL RELEVANCE

Baitouweng decoction (BTW) has been used for hundreds of years to treat ulcerative colitis (UC) in China and has produced remarkable clinical results. However, the knowledge in protective mechanism of BTW against UC is still unclear.

AIM OF THE STUDY

The present study was designed to investigate the anti-UC effects of BTW and the underlying mechanisms involved.

METHODS

3.5% dextran sulfate sodium (DSS)-induced experimental colitis was used to simulate human UC and the mice were treated with BTW (6.83 g/kg), leucine (200 mg/kg, Leu) or rapamycin (2 mg/kg, RAPA) as a positive control for 7 days. The clinical symptoms, serum myeloperoxidase (MPO) and malondialdehyde (MDA) levels were evaluated. Biological samples were collected to detect the effects of BTW on mechanistic target of rapamycin complex 1 (mTORC1) pathway and Leu metabolism.

RESULTS

In our study, BTW notably improved the clinical symptoms and histopathological tissue damage and reduced the release of proinflammatory cytokines, including IL-6, IL-1β and TNF-α in UC mice. BTW also alleviated oxidative stress by decreasing serum MPO and MDA levels. Additionally, BTW significantly suppressed mTORC1 activity in the colon tissues of UC mice. Serum metabolomics analysis revealed that the mice receiving BTW had lower Leu levels, which was in line with the decreased expression of branched-chain α-keto acid dehydrogenase kinase (BCKDK) in the colon tissues. Furthermore, oral administration of Leu aggravated DSS-induced acute colitis and enhanced mTORC1 activity in the colon.

CONCLUSION

These data strongly demonstrated that BTW could ameliorate DSS-induced UC by regulating the Leu-related mTORC1 pathway and reducing oxidative stress.

Analysis of Systemic Epigenetic Alterations in Inflammatory Bowel Disease: Defining Geographical, Genetic and Immune-Inflammatory influences on the Circulating Methylome

BACKGROUND

Epigenetic alterations may provide valuable insights into gene-environment interactions in the pathogenesis of inflammatory bowel disease [IBD].

METHODS

Genome-wide methylation was measured from peripheral blood using the Illumina 450k platform in a case-control study in an inception cohort (295 controls, 154 Crohn's disease [CD], 161 ulcerative colitis [UC], 28 IBD unclassified [IBD-U)] with covariates of age, sex and cell counts, deconvoluted by the Houseman method. Genotyping was performed using Illumina HumanOmniExpressExome-8 BeadChips and gene expression using the Ion AmpliSeq Human Gene Expression Core Panel. Treatment escalation was characterized by the need for biological agents or surgery after initial disease remission.

RESULTS

A total of 137 differentially methylated positions [DMPs] were identified in IBD, including VMP1/MIR21 [p = 9.11 × 10-15] and RPS6KA2 [6.43 × 10-13], with consistency seen across Scandinavia and the UK. Dysregulated loci demonstrate strong genetic influence, notably VMP1 [p = 1.53 × 10-15]. Age acceleration is seen in IBD [coefficient 0.94, p < 2.2 × 10-16]. Several immuno-active genes demonstrated highly significant correlations between methylation and gene expression in IBD, in particular OSM: IBD r = -0.32, p = 3.64 × 10-7 vs non-IBD r = -0.14, p = 0.77]. Multi-omic integration of the methylome, genome and transcriptome also implicated specific pathways that associate with immune activation, response and regulation at disease inception. At follow-up, a signature of three DMPs [TAP1, TESPA1, RPTOR] were associated with treatment escalation to biological agents or surgery (hazard ratio of 5.19 [CI: 2.14-12.56], logrank p = 9.70 × 10-4).

CONCLUSION

These data demonstrate consistent epigenetic alterations at diagnosis in European patients with IBD, providing insights into the pathogenetic importance and translational potential of epigenetic mapping in complex disease.

Immunometabolism and microbial metabolites at the gut barrier: Lessons for therapeutic intervention in inflammatory bowel disease

The concept of immunometabolism has emerged recently whereby the repolarizing of inflammatory immune cells toward anti-inflammatory profiles by manipulating cellular metabolism represents a new potential therapeutic approach to controlling inflammation. Metabolic pathways in immune cells are tightly regulated to maintain immune homeostasis and appropriate functional specificity. Because effector and regulatory immune cell populations have different metabolic requirements, this allows for cellular selectivity when regulating immune responses based on metabolic pathways. Gut microbes have a major role in modulating immune cell metabolic profiles and functional responses through extensive interactions involving metabolic products and crosstalk between gut microbes, intestinal epithelial cells, and mucosal immune cells. Developing strategies to target metabolic pathways in mucosal immune cells through the modulation of gut microbial metabolism has the potential for new therapeutic approaches for human autoimmune and inflammatory diseases, such as inflammatory bowel disease. This review will give an overview of the relationship between metabolic reprogramming and immune responses, how microbial metabolites influence these interactions, and how these pathways could be harnessed in the treatment of inflammatory bowel disease.

3,6-dichlorobenzo[b]thiophene-2-carboxylic acid alleviates ulcerative colitis by suppressing mammalian target of rapamycin complex 1 activation and regulating intestinal microbiota

BACKGROUND

3,6-dichlorobenzo[b]thiophene-2-carboxylic acid (BT2) is a benzothiophene carboxylate derivative that can suppress the catabolism of branched-chain amino acid (BCAA)-associated mammalian target of rapamycin complex 1 (mTORC1) activation. Previous studies have demonstrated the therapeutic effects of BT2 on arthritis, liver cancer, and kidney injury. However, the effects of BT2 on ulcerative colitis (UC) are unknown.

AIM

To investigate the anti-UC effects of BT2 and the underlying mechanism.

METHODS

Mouse UC models were created through the administration of 3.5% dextran sodium sulfate (DSS) for 7 d. The mice in the treated groups were administered salazosulfapyridine (300 mg/kg) or BT2 (20 mg/kg) orally from day 1 to day 7. At the end of the study, all of the mice were sacrificed, and colon tissues were removed for hematoxylin and eosin staining, immunoblot analyses, and immunohistochemical assays. Cytokine levels were measured by flow cytometry. The contents of BCAAs including valine, leucine, and isoleucine, in mouse serum were detected by liquid chromatography-tandem mass spectrometry, and the abundance of intestinal flora was analyzed by 16S ribosomal DNA sequencing.

RESULTS

Our results revealed that BT2 significantly ameliorated the inflammatory symptoms and pathological damage induced by DSS in mice. BT2 also reduced the production of the proinflammatory cytokines interleukin 6 (IL-6), IL-9, and IL-2 and increased the anti-inflammatory cytokine IL-10 level. In addition, BT2 notably improved BCAA catabolism and suppressed mTORC1 activation and cyclooxygenase-2 expression in the colon tissues of UC mice. Furthermore, high-throughput sequencing revealed that BT2 restored the gut microbial abundance and diversity in mice with colitis. Compared with the DSS group, BT2 treatment increased the ratio of Firmicutes to Bacteroidetes and decreased the abundance of Enterobacteriaceae and Escherichia-Shigella.

CONCLUSION

Our results indicated that BT2 significantly ameliorated DSS-induced UC and that the latent mechanism involved the suppression of BCAA-associated mTORC1 activation and modulation of the intestinal flora.

Exploring the Molecular Mechanism of Tong Xie Yao Fang in Treating Ulcerative Colitis Using Network Pharmacology and Molecular Docking

Objective. The purpose of this study was to investigate the mechanisms of action of Tong Xie Yao Fang (TXYF) against ulcerative colitis (UC) by employing a network pharmacology approach. Methods. The network pharmacology approach, including screening of the active ingredients and targets, construction of the active ingredient-drug target network, the active ingredient-diseasetarget network, the protein–protein interaction (PPI) network, enrichment analyses, molecular docking, and targets validation, was used to explore the mechanisms of TXYF against UC. Results. 34 active ingredients and 129 and 772 targets of TXYF and UC, respectively, were identified. The intersection of the active ingredient-drug target network, the active ingredient-disease target network, and the PPI network suggested that kaempferol, beta-sitosterol, wogonin, and naringenin were the core ingredients and prostaglandin-endoperoxide synthase 2 (PTGS2) was the core target. Enrichment analyses showed that regulation of exogenous protein binding and other functions were of great significance. Nuclear factor-kappa B (NF-κB) signaling pathway, interleukin-17 (IL-17) signaling pathway, and tumor necrosis factor (TNF) signaling pathway were important pathways. Results of molecular docking indicated that the core ingredients and the target molecule had strong binding affinities. We have validated the high levels of expression of PTGS2 in UC by analyzing three additional datasets from the Gene Expression Omnibus (GEO) database. Conclusions. There are multiple ingredients, targets, and pathways involved in TXYF’s effectiveness against UC, and these findings will promote further research and clinical applications.

Repurposing metformin as a potential treatment for inflammatory bowel disease: Evidence from cell to the clinic

Inflammatory bowel disease (IBD) comprises a group of intestinal disorders, including ulcerative colitis and Crohn's disease. Currently, the incidence and prevalence of IBD are increasing globally. Although both biologic agents and small molecule drugs have been available for treatment of IBD patients, approximately one third of treated patients do not respond to these treatments. Therefore, novel therapy or repurposing of drugs have been extensively studied to obtain an effective therapy for IBD patients. Among these drugs, metformin has been reported to exert beneficial effects in many organs via its anti-inflammatory effect. Additionally, evidence from cellular to clinical models of IBD demonstrated significant positive effects of metformin on inflammatory pathways, oxidative stress, gut barrier integrity, and gut microbiota. In this review, the beneficial effects of metformin on IBD are comprehensively summarized and discussed using the results of in vitro, in vivo, and clinical studies. Increased understanding of these protective effects and the underlying mechanisms may pave the way for effective use of metformin in IBD patients.

Selenium-enriched Bifidobacterium longum DD98 effectively ameliorates dextran sulfate sodium-induced ulcerative colitis in mice

The pathogenesis of ulcerative colitis (UC) is complicated with impaired intestinal epithelial barrier and imbalanced gut microbiota. Both selenium and probiotics have shown effects in regulating intestinal flora and ameliorating UC. The objective of this study is to investigate the alleviating effects of Selenium-enriched Bifidobacterium longum DD98 (Se-B. longum DD98) on dextran sulfate sodium (DSS)-induced colitis in mice and explore the underlying mechanism. After treatment of B. longum DD98, Se-B. longum DD98, and sulfasalazine for 3 weeks, the disease severity of UC mice was decreased, with colon lengthened and pathological phenotype improved. The expression of pro-inflammatory cytokines and oxidative stress parameters were also decreased. Thus, Se-B. longum DD98 showed a stronger effect on relieving the aforementioned symptoms caused by DSS-induced colitis. Exploration of the potential mechanism demonstrated that Se-B. longum DD98 showed higher activities to suppress the inflammatory response by inhibiting the activation of the toll-like receptor 4 (TLR4), compared to B. longum DD98 and sulfasalazine. Se-B. longum DD98 also significantly improved the intestinal barrier integrity by increasing the expression of tight junction proteins including ZO-1 and occludin. 16S rDNA sequencing analyses showed that Se-B. longum DD98 improved the diversity of the intestinal flora and promoted the abundance of health-benefiting taxa including Lachnospiraceae, Lactobacillaceae, and Prevotellaceae in family level. In conclusion, compared to B. longum DD98 and sulfasalazine, Se-B. longum DD98 showed stronger therapeutic effects on DSS-induced colitis in mice and might be a promising candidate for the treatment of UC.

Immunomodulatory activity of trifluoromethyl arylamides derived from the SRPK inhibitor SRPIN340 and their potential use as vaccine adjuvant

The serine/arginine-rich protein kinases (SRPK) specifically phosphorylate their substrates at RS-rich dipeptides, which are abundantly found in SR splicing factors. SRPK are classically known for their ability to affect the splicing and expression of gene isoforms commonly implicated in cancer and diseases associated with infectious processes. Non-splicing functions have also been attributed to SRPK, which highlight their functional plasticity and relevance as therapeutic targets for pharmacological intervention. In this sense, different SRPK inhibitors have been developed, such as the well-known SRPIN340 and its derivatives, with anticancer and antiviral activities. Here we evaluated the potential immunomodulatory activity of SRPIN340 and three trifluoromethyl arylamide derivatives. In in vitro analysis with RAW 264.7 macrophages and primary splenocytes, all the compounds modulated the expression of immune response mediators and antigen-presentation molecules related to a tendency for M2 macrophage polarization. Immunization experiments were carried out in mice to evaluate their potential as vaccine immunostimulants. When administrated alone, the compounds altered the expression of immune factors at the injection site and did not produce macroscopic or microscopic local reactions. In addition, when prepared as an adjuvant with inactivated EHV-1 antigens, all the compounds increased the anti-EHV-1 neutralizing antibody titers, a change that is consistent with an increased Th2 response. These findings demonstrate that SRPIN340 and its derivatives exhibit a noticeable capacity to modulate innate and adaptative immune cells, disclosing their potential to be used as vaccine adjuvants or in immunotherapies.

Nuciferine Regulates Immune Function and Gut Microbiota in DSS-Induced Ulcerative Colitis

Nuciferine, a major aporphine alkaloid obtained from the leaves of Nelumbo nucifera, exhibits anti-cancer and anti-inflammatory properties; however, its protective effects against inflammatory bowel diseases (IBD) has never been explored. In this study, an ulcerative colitis (UC) model was established in BALb/c mice by the continuous administration of 5% dextran sulfate sodium (DSS) in drinking water for 1 week. From day 8 to day 14, the DSS-treated mice were divided into a high-dose and a low-dose nuciferine treatment group and were intraperitoneally injected with the corresponding dose of the drug. Body weight loss, disease activity index (DAI), and colon length were measured. Histological changes were observed using hematoxylin and eosin staining. T lymphocyte proliferation was assessed by MTT assay. The ratio of CD3+, CD4+, CD8+, Th1, Th2, Th17, and Treg cells were estimated by flow cytometry. Finally, 16S rRNA sequencing was performed to compare the composition and relative abundance of the gut microbiota among the different treatment groups. The results showed that nuciferine treatment led to a significant improvement in symptoms, such as histological injury and colon shortening in mice with DSS-induced UC. Nuciferine treatment improved the Th1/Th2 and Treg/Th17 balance in the DSS-induced IBD model, as well as the composition of the intestinal microflora. At the phylum level, compared with the control group, the abundance of Firmicutes and Actinobacteriota was decreased in the model group, whereas that of Bacteroidetes increased. Meanwhile, at the genus level, compared with the control group, the numbers of the genera Lachnospiraceae_Clostridium, Bilophila and Halomonas reduced in the model group, while those of Bacteroides, Parabacteroides, and Paraprevotella increased. Notably, nuciferine administration reversed this DSS-induced gut dysbiosis. These results indicated that nuciferine modulates gut microbiota homeostasis and immune function in mice with DSS-induced UC.

Anti-inflammatory and intestinal microbiota modulation properties of high hydrostatic pressure treated cyanidin-3-glucoside and blueberry pectin complexes on dextran sodium sulfate-induced ulcerative colitis mice

This study investigated the anti-inflammatory effects of cyanidin-3-glucoside (C3G) and blueberry pectin (BP) complexes on mice with dextran sodium sulfate (DSS)-induced colitis before and after high hydrostatic pressure (HHP) treatment. Real-time polymerase chain reaction (RT-PCR), western blotting, and 16S rDNA sequencing were used to study the expression of inflammation-related factors, activation of signal pathway-related proteins, and changes in the intestinal flora in ulcerative colitis (UC) mice. The results showed that HHP-treated C3G-BP complexes significantly relieved diarrhea and blood loss in the stool of UC mice and alleviated colon shortening. The potential mechanism of action involved reduction in intestinal oxidative stress mRNA expression of pro-inflammatory factors, improvement in anti-inflammatory factor levels, inhibition of the NF-κB signaling pathway, increased protein levels of Bcl-2/Bax and caspase-3/cleaved caspase-3 genes, and improved gut microbiota composition. Compared with other experimental groups, the HHP-treated C3G-BP complexes group exhibited the best anti-inflammatory effect on DSS-induced UC mice. The results may provide new ideas for using C3G-BP complexes for treating UC and help develop better processing methods.

Molecular mechanisms of Huanglian jiedu decoction on ulcerative colitis based on network pharmacology and molecular docking

Huanglian jiedu decoction (HLJDD) is a heat-clearing and detoxifying agent composed of four kinds of Chinese herbal medicine. Previous studies have shown that HLJDD can improve the inflammatory response of ulcerative colitis (UC) and maintain intestinal barrier function. However, its molecular mechanism is not completely clear. In this study, we verified the bioactive components (BCI) and potential targets of HLJDD in the treatment of UC using network pharmacology and molecular docking, and constructed the pharmacological network and PPI network. Then the core genes were enriched by GO and KEGG. Finally, the bioactive components were docked with the key targets to verify the binding ability between them. A total of 54 active components related to UC were identified. Ten genes are very important to the PPI network. Functional analysis showed that these target genes were mainly involved in the regulation of cell response to different stimuli, IL-17 signal pathway and TNF signal pathway. The results of molecular docking showed that the active components of HLJDD had a good binding ability with the Hub gene. This study systematically elucidates the “multi-component, multi-target, multi-pathway” mechanism of anti-UC with HLJDD for the first time, suggesting that HLJDD or its active components may be candidate drugs for the treatment of ulcerative colitis.

Latilactobacillus curvatus BYB3 Isolated from Kimchi Alleviates Dextran Sulfate Sodium (DSS)-Induced Colitis in Mice by Inhibiting IL-6 and TNF-R1 Production

Recent studies have shown that probiotics have health-promoting effects, particularly intestinal immune modulation. In this study, we focused on the immunomodulatory properties of Latilactobacillus curvatus BYB3, formerly called Lactobacillus curvatus, isolated from kimchi. In a mouse model of 14-day dextran sulfate sodium (DSS)-induced colitis, treatment with L. curvatus BYB3 significantly decreased the disease activity index, colon length, and weight loss. Moreover, histological analyses showed that L. curvatus BYB3 protected the structural integrity of the intestinal epithelial layer and mucin-secreting goblet cells from DSS-induced damage, with only slight infiltration by immune cells. To evaluate the molecular mechanisms underlying L. curvatus BYB3-driven inhibition of interleukin 6 production, possible in vivo anti-inflammatory effects of L. curvatus BYB3 were examined in the same mouse model. In addition, significantly lower levels of IL-6 and tumor necrosis factor receptor 1 upregulation were seen in the DSS+BYB3 group (compared to that in the DSS group). These results indicate that L. curvatus BYB3 exhibits health-promoting effects via immune modulation; and therefore, it can be used to treat various inflammatory diseases.

3,4-Dihydroxyphenylethanol (DPE or Hydroxytyrosol) Counteracts ERK1/2 and mTOR Activation, Pro-Inflammatory Cytokine Release, Autophagy and Mitophagy Reduction Mediated by Benzo[a]pyrene in Primary Human Colonic Epithelial Cells

Understanding the effects induced by carcinogens on primary colonic epithelial cells and how to counteract them might help to prevent colon cancer, which is one of the most frequent and aggressive cancers. In this study, we exposed primary human colonic epithelial cells (HCoEpC) to Benzo[a]pyrene (B[a]P) and found that it led to an increased production of pro-inflammatory cytokines and activated ERK1/2 and mTOR. These pathways are known to be involved in inflammatory bowel disease (IBD), which represents a colon cancer risk factor. Moreover, B[a]P reduced autophagy and mitophagy, processes whose dysregulation has been clearly demonstrated to predispose to cancer either by in vitro or in vivo studies. Interestingly, all the effects induced by B[a]P could be counteracted by 3,4-Dihydroxyphenylethanol (DPE or Hydroxytyrosol, H), the most powerful anti-inflammatory and antioxidant compound contained in olive oil. This study sheds light on the mechanisms that could be involved in colon carcinogenesis induced by a chemical carcinogen and identifies a safe natural product that may help to prevent them.

Divergent regulation of inflammatory cytokines by mTORC1 in THP-1-derived macrophages and intestinal epithelial Caco-2 cells

AIMS

The sustained activation of intestinal mechanistic target of rapamycin complex 1 (mTORC1) brought about by repeated mucosal insult or injury has been linked to escalation of gut inflammatory response, which may progress to damage the epithelium if not controlled. This study investigated the role of mTORC1 in the response of macrophage and enterocyte to inflammatory stimuli.

MATERIALS AND METHODS

We genetically manipulated human THP-1 monocytes and epithelial intestinal Caco-2 cells to generate stable cell lines with baseline, low or high mTORC1 kinase activity. The effects of THP-1 macrophage secretions onto Caco-2 cells were investigated by means of conditioned media transfer experiments.

KEY FINDINGS

The priming of mTORC1 for activation promoted lipopolysaccharide (LPS)-mediated THP-1 macrophage immune response as evidenced by the stimulation of inflammatory mediators (TNFα, IL-6, IL-8, IL-1β and IL-10). The treatment of THP-1 macrophages with LPS more than the manipulated level of mTORC1 activity of macrophages determined whether cytokine gene expression was induced in Caco-2 cells. LPS carry over was not responsible for the stimulation of Caco-2 cells' cytokine response. Knocking down Raptor in Caco-2 cells or treating Caco-2 cells with rapamycin enhanced Caco-2 TNFα gene expression revealing the anti-inflammatory role of a functional mTORC1 in intestinal epithelial cells exposed to macrophage-derived pro-inflammatory stimuli.

SIGNIFICANCE

Taken together, mTORC1 differentially impacts the immune responses of THP-1-derived macrophages and Caco-2 epithelial cells when placed in a pro-inflammatory microenvironment.

Targeting Immune Cell Metabolism in the Treatment of Inflammatory Bowel Disease

The cells of the immune system are highly dynamic, constantly sensing and adapting to changes in their surroundings. Complex metabolic pathways govern leukocytes' ability to fine-tune their responses to external threats. Mammalian target of rapamycin complex 1 and hypoxia inducible factor are important hubs of these pathways and play a critical role coordinating cell activation and proliferation and cytokine production. For this reason, these molecules are attractive therapeutic targets in inflammatory disease. Insight into perturbations in immune cell metabolic pathways and their impact on inflammatory bowel disease (IBD) progression are starting to emerge. However, it remains to be determined whether the aberrations in immune metabolism that occur in gut resident immune cells contribute to disease pathogenesis or are reflected in the peripheral blood of patients with IBD. In this review, we explore what is known about the metabolic profile of T cells, monocytes, macrophages, dendritic cells, and natural killer cells in IBD and discuss the potential of manipulating immune cell metabolism as a novel approach to treating IBD.

RORα is critical for mTORC1 activity in T cell-mediated colitis

Inflammatory bowel disease (IBD) is multi-factorial chronic intestinal inflammation driven by pathogenic T cells, among which a large portion of patients are resistant to current anti-inflammatory regimes. The mechanisms underlying colitis pathogenicity and drug resistance are not fully understood. Here, we demonstrate that RORα is highly expressed in active UC patients, particularly in those non-responsive to anti-TNF treatment. Rorα deficiency in CD4⁺ T cells greatly reduced colitis development. Mechanistically, RORα regulated T cell infiltration in colon and inhibited T cell apoptosis. Meanwhile, genome-wide occupancy and transcriptome analysis revealed that RORα promoted mTORC1 activation. mTORC1 signaling, also hyperactivated in active UC patients, is necessary for T cell-mediated colitis. Our results thus demonstrate a crucial role of the RORα-mTORC1 axis in CD4⁺ T cells in promoting IBD, which may be targeted in human patients.

An Immunologic Compatibility Testing Was Not Useful for Donor Selection in Fecal Microbiota Transplantation for Ulcerative Colitis

Fecal microbiota transplantation (FMT) is an effective procedure against Clostridioides difficile infection (CDI), with promising but still suboptimal performance in other diseases, such as ulcerative colitis (UC). The recipient’s mucosal immune response against the donor’s microbiota could be relevant factor in the effectiveness of FMT. Our aim was to design and validate an individualized immune-based test to optimize the fecal donor selection for FMT. First, we performed an in vitro validation of the test by co-culturing lymphocytes obtained from the small intestine mucosa of organ donor cadavers (n=7) and microbe-associated molecular patterns (MAMPs) obtained from the feces of 19 healthy donors. The inflammatory response was determined by interleukin supernatant quantification using the Cytometric Bead Array kit (B&D). We then conducted a clinical pilot study with 4 patients with UC using immunocompetent cells extracted from rectal biopsies and MAMPs from 3 donor candidates. We employed the test results to guide donor selection for FMT, which was performed by colonoscopy followed by 4 booster instillations by enema in the following month. The microbiome engraftment was assessed by 16S rDNA massive sequencing in feces, and the patients were clinically followed-up for 16 weeks. The results demonstrated that IL-6, IL-8, and IL-1ß were the most variable markers, although we observed a general tolerance to the microbial insults. Clinical and colonoscopy remission of the patients with UC was not achieved after 16 weeks, although FMT provoked enrichment of the Bacteroidota phylum and Prevotella genus, with a decrease in the Actinobacteriota phylum and Agathobacter genus. The most relevant result was the lack of Akkermansia engraftment in UC. In summary, the clinical success of FMT in patients with UC appears not to be influenced by donor selection based on the explored recipient’s local immunological response to FMT, suggesting that this approach would not be valid for FMT fecal donor optimization in such patients.

mTORC1 silencing during intestinal epithelial Caco-2 cell differentiation is mediated by the activation of the AMPK/TSC2 pathway

The mechanistic target of rapamycin complex 1 (mTORC1) signaling is the prototypical pathway regulating protein synthesis and cell proliferation. The level of mTORC1 activity is high in intestinal stem cells located at the base of the crypts and thought to gradually decrease as transit-amplifying cells migrate out of the crypts and differentiate into enterocytes, goblet cells or enteroendocrine cells along the epithelium. The unknown mechanism responsible for the silencing of intestinal epithelium mTORC1 during cell differentiation was investigated in Caco-2 cells, which spontaneously differentiate into enterocytes in standard growth medium. The results show that TSC2, an upstream negative regulator of mTORC1 was central to mTORC1 silencing in differentiated Caco-2 cells. AMPK-mediated activation of TSC2 (Ser1387) and repression of Raptor (Ser792), an essential component of mTORC1, were stimulated in differentiated Caco-2 cells. ERK1/2-mediated repression of TSC2 (Ser664) seen in undifferentiated Caco-2 cells was lifted in differentiated cells. IRS-1-mediated activation of AKT (Thr308) phosphorylation was stimulated in differentiated Caco-2 cells and may be involved in cross-pathway repression of ERK1/2. Additionally, PRAS40 (Thr246) phosphorylation was decreased in differentiated Caco-2 cells compared to undifferentiated cells allowing dephosphorylated PRAS40 to displace Raptor thereby repressing mTORC1 kinase activity.

Combination of polysaccharides from Astragalus membranaceus and Codonopsis pilosula ameliorated mice colitis and underlying mechanisms

ETHNOPHARMACOLOGICAL RELEVANCE

Astragalus membranaceus and Codonopsis pilosula which are two Chinese medicinal herbs are often combinedly used as monarch drugs in Traditional Chinese Medicine (TCM) prescriptions to treat ulcerative colitis (UC). However, the exact mechanisms and effective constituents of the two herbs remain unclear.

AIM OF THE STUDY

Polysaccharides are the main active ingredients of the two medicinal herbs and some specific polysaccharides extracted from the two medicinal herbs have been proven effective in relieving colitis. Hence, we speculated that polysaccharides of the two medicinal herbs may be the material basis for compatibility in TCM prescriptions to treat UC. In the research, total polysaccharides of A. membranaceus and C. pilosula extractum, named AERP and CERP respectively, were administrated to 2.5% dextran sulfate sodium (DSS)-induced acute colitis mice by dosing alone and in combination to test this hypothesis.

MATERIALS AND METHODS

5-aminosalicylic acid (5-ASA, 100 mg/kg/d) was selected as the positive drug. The basic indexes of colitis mice including body weight, stool bleeding, stool consistency and colon lengths were recorded. In addition, tissue inflammatory factors, mucosa-associated proteins, fecal short chain fatty acids (SCFAs) and gut microbiota were also analyzed.

RESULTS

The co-administration of AERP and CERP at specific doses could improve the clinical symptoms, reestablish the immune balance, and alleviate colonic mucosal injury in colitis mice. The unique efficacy of co-administration relied on activation of the aryl hydrocarbon receptor (AhR) and up-regulation of isovaleric acid and butyrate. In addition, the structure of intestinal flora was recovered in the co-administration group.

CONCLUSION

Our research proved the efficacy after co-administration of total polysaccharides from A. membranaceus and C. pilosula on colitis mice which provided a theoretical basis for their compatibility in TCM prescriptions to treat UC.

Curcumin steers THP-1 cells under LPS and mTORC1 challenges toward phenotypically resting, low cytokine-producing macrophages

The persistent activation of intestinal mechanistic target of rapamycin complex 1 (mTORC1) triggered by mucosal stress has been linked to deregulation of the gut immune response resulting in intestinal inflammation and cell death. The present study investigated the regulatory properties of food-derived mTORC1 modulators, curcumin, and piperine, toward the polarization of stimulated macrophages and the differentiation of monocytes at two mTORC1 activity levels (baseline and elevated). To that end, we created stable human THP-1 monocytes exhibiting normal or constitutively active mTORC1. Curcumin or its combination with piperine, but not piperine alone, suppressed mTORC1 kinase activity, curtailed lipopolysaccharide-mediated inflammatory response of THP-1 macrophages, and repressed macrophage activation by inhibiting signaling pathways involved in M1 (mTORC1) and M2 (mTORC2 and cAMP response element binding protein) polarization. The effects of piperine in the curcumin/piperine combination were modest overall, indicating it was curcumin that modulated differentiating monocytes into acquiring a M0 macrophage phenotype characterized by low inflammatory cytokine output.

Curcumin represses mTORC1 signaling in Caco-2 cells by a two-sided mechanism involving the loss of IRS-1 and activation of AMPK

The mechanistic target of rapamycin complex 1 (mTORC1) is a central modulator of inflammation and tumorigenesis in the gastrointestinal tract. Growth factors upregulate mTORC1 via the PI3K/AKT and/or Ras/MAPK signal pathways. Curcumin (CUR), a polyphenol found in turmeric roots (Curcuma longa) can repress mTORC1 kinase activity in colon cancer cell lines; however, key aspects of CUR mechanism of action remain to be elucidated including its primary cellular target. We investigated the molecular effects of physiologically attainable concentration of CUR (20 μM) in the intestinal lumen on mTORC1 signaling in Caco-2 cells. CUR markedly inhibited mTORC1 kinase activity as determined by the decreased phosphorylation of p70S6K (Thr389, -99%, P < 0.0001) and S6 (Ser235/236, -92%, P < 0.0001). Mechanistically, CUR decreased IRS-1 protein abundance (-80%, P < 0.0001) thereby downregulating AKT phosphorylation (Ser473, -94%, P < 0.0001) and in turn PRAS40 phosphorylation (Thr246, -99%, P < 0.0001) while total PRAS40 abundance was unchanged. The use of proteasome inhibitor MG132 showed that CUR-mediated loss of IRS-1 involved proteasomal degradation. CUR lowered Raptor protein abundance, which combined with PRAS40 hypophosphorylation, suggests CUR repressed mTORC1 activity by inducing compositional changes that hinder the complex assembly. In addition, CUR activated AMPK (Thr172 phosphorylation, P < 0.0001), a recognized repressor of mTORC1, and AMPK upstream regulator LKB1. Although cargo adapter protein p62 was decreased by CUR (-49%, P < 0.004), CUR did not significantly induce autophagy. Inhibition of AKT/mTORC1 signaling by CUR may have lifted the cross-inhibition onto MAPK signaling, which became induced; p-ERK1/2 (+670%, P < 0.0001), p-p38 (+1433%, P < 0.0001). By concomitantly targeting IRS-1 and AMPK, CUR's mechanism of mTORC1 inhibition is distinct from that of rapamycin.

Onion bulb extract can both reverse and prevent colitis in mice via inhibition of pro-inflammatory signaling molecules and neutrophil activity

Background

Onion is one of the most commonly used plants in the traditional medicine for the treatment of various diseases. We recently demonstrated the anti-inflammatory properties of onion bulb extract (OBE) in reducing colitis severity in mice when administered at the same time of colitis induction. However, whether onion can reverse established colitis or even prevent its development has not been investigated.

Hypothesis

To test 1. whether OBE can reduce colitis severity when given either before (preventative approach) or after (treatment approach) colitis induction and if so, 2. what are the mechanisms by which onion can achieve these effects.

Methods

Colitis was induced by dextran sulfate sodium (DSS) administration using treatment and preventative approaches. The severity of the inflammation was determined by the gross and histological assessments. The colonic level/activity of pro-inflammatory molecules and immune cell markers was assessed by immunofluorescence and western blotting analysis. In vitro neutrophil superoxide release and survival was assessed by chemilumenecense and Annexin-V/7AAD assays respectively.

Results

OBE treatment significantly reduced colitis severity in both approaches, the colonic expression/activity profile of pro-inflammatory molecules, inhibited WKYMVm-induced superoxide release, and increased spontaneous apoptosis of neutrophils in vitro.

Conclusions

OBE can be used as an effective option in the prevention and/or the treatment of established colitis.

Standardized Fraction of Turbinaria ornata Alleviates Dextran Sulfate Sodium-Induced Chronic Colitis in C57BL/6 Mice via Upregulation of FOXP3+ Regulatory T Cells

Turbinaria ornata is a tropical brown algae (seaweed) known to have anti-inflammatory properties. In this study, we analyzed T. ornata extract (TOE) using liquid chromatography quadrupole time of flight mass spectrometry (LC-QTOF-MS) and nuclear magnetic resonance (NMR) and evaluated the in vivo efficacy of TOE against dextran sulfate sodium-induced chronic colitis in C57BL/6 mice. The bioactive fraction of TOE was administered orally daily for 6 weeks to mice under different treatments normal, colitis, and colitis + conventional drug (5-aminosalicylic acid, 5-ASA). Regarding clinical manifestation, the disease activity index and colon length of the colitis + TOE group were significantly reduced compared to those of the colitis group. The results of myeloperoxidase activity and histopathological examination showed similar results. Western blot analysis of colon tissues revealed that cyclooxygenase-2, tumor necrosis factor alpha (TNF-α), and phosphorylated signal transducer and activator of transcription-3 (p-STAT3) were significantly decreased in the colitis + 5-ASA group, whereas forkhead box P3 (FOXP3) was increased. qPCR results showed changes in T cell subsets; the administration of TOE upregulated regulatory T cell (Treg) expression, although T helper 17 cell (Th17) expression did not change significantly. Interestingly, the colitis + TOE group showed high levels of both Th1 and Th2 transcription factors, but the secreted cytokine interferon (IFN)-γ and interleukin (IL)-4 remained unchanged and somewhat reduced. Additionally, TNF-α gene expression was significantly reduced in the colitis + TOE group. IL-6 mRNA levels were also decreased, although not significantly. Four compounds were structurally elucidated using 1D- and 2D-NMR spectroscopy, and five compounds were fully identified or tentatively characterized using LC-QTOF-MS. In conclusion, TOE could alleviate chronic colitis via upregulation of Foxp3+ Treg cells and production of the anti-inflammatory cytokine IL-10, which directly inhibits macrophages and pro-inflammatory cytokine synthesis, leading to reduced colitis.

REC8 suppresses tumor angiogenesis by inhibition of NF-κB-mediated vascular endothelial growth factor expression in gastric cancer cells

Background

Tumor angiogenesis is an essential event for tumor growth and metastasis. It has been showed that REC8, a component of the meiotic cohesion complex, played a vital role in Epithelial-Mesenchymal Transition (EMT) in gastric cancer. However, the role of REC8 in gastric cancer angiogenesis remains to be identified.

Results

Inhibition of REC8 expression in gastric cancer cells contributed to tumor angiogenesis in the gastric cancer microenvironment. The clinical analysis demonstrated that the loss of REC8 in gastric cancer with enrichment of MVD. Depletion of REC8 expression in gastric cancer cells significantly increased tube formation of human umbilical vein endothelial cells (HUVECs), which is attributed to enhancement of vascular endothelial growth factor (VEGF) secretion caused by REC8 slicing. While addition of neutralizing antibody targeted VEGF into supernatant drastically reversed the effect of REC8 loss in gastric cancer cells on tube formation. Mechanistic analyses indicated that ablation of REC8 promotes nuclear factor-κB (NF-κB) p65 activity and its downstream gene VEGF expression, leading to tube formation.

Conclusions

These results demonstrated a novel REC8 function that suppressed tumor angiogenesis and progression by attenuation of VEGF in gastric cancer microenvironment.

Electronic supplementary material

The online version of this article (10.1186/s40659-020-00307-1) contains supplementary material, which is available to authorized users.

mTOR sustains inflammatory response in celiac disease

Celiac disease (CD) is an enteropathy triggered by the ingestion of gluten proteins in genetically predisposed individuals and characterized by excessive activation of effector immune cells and enhanced production of inflammatory cytokines. However, factors/mechanisms that amplify the ongoing mucosal inflammation in CD are not fully understood. In this study, we assessed whether mammalian target of Rapamycin (mTOR), a pathway that combines intra- and extra-cellular signals and acts as a central regulator for the metabolism, growth, and function of immune and non-immune cells, sustains CD-associated immune response. Our findings indicate that expression of phosphorylated (p)/active form of mTOR is increased in protein lysates of duodenal biopsy samples taken from patients with active CD (ACD) as compared to normal controls. In ACD, activation of mTOR occurs mainly in the epithelial compartment and associates with enhanced expression of p-4EBP, a downstream target of mTOR complex (mTORC)1, while expression of p-Rictor, a component of mTORC2, is not increased. Stimulation of mucosal explants of inactive CD patients with pepsin-trypsin-digested (PT)-gliadin or IFN-γ/IL-21, two cytokines produced in CD by gluten-specific T cells, increases p-4EBP expression. Consistently, blockade of such cytokines in cultures of ACD mucosal explants reduces p-4EBP. Finally, we show that inhibition of mTORC1 with rapamycin in ACD mucosal explants reduces p-4EBP and production of IL-15, a master cytokine produced by epithelial cells in this disorder. Our data suggest that ACD inflammation is marked by activation of mTORC1 in the epithelial compartment.

2'-fucosyllactose inhibits imiquimod-induced psoriasis in mice by regulating Th17 cell response via the STAT3 signaling pathway

Psoriasis is a chronic immune-mediated inflammatory cutaneous disorder with Th17 cells and Th17-related cytokines playing an important role in its development. 2'-FL (2'-fucosyllactose), which makes up about 30% of all HMOs (human milk oligosaccharides) in blood type secretor positive maternal milk, plays an essential role in supporting aspects of immune development and regulation. To explore the immunomodulatory effect of 2'-FL in psoriasis, we employed the imiquimod (IMQ)-induced psoriasis-like mouse model. Our data showed that mice administered with 2'-FL exhibited attenuated skin damage and inflammation, characterized by significantly decreased erythema and thickness and reduced recruitment of pro-inflammatory cytokines, when compared to control mice. The alleviated skin inflammation in 2'-FL treated mice was associated with a reduced proportion of Th17 cells and decreased production of Th17-related cytokines. Furthermore, we have demonstrated that 2'-FL reduced the phosphorylation of STAT3 in the skin tissue from mice with IMQ stimulation, which could account for the decreasing recruitment of Th17 cells. In vitro studies showed that 2'-FL inhibited differentiation of Th17 cells, phosphorylation of STAT3, and RORγt mRNA levels in T cells under Th17 polarization. Our results indicate that 2'-FL ameliorates IMQ-induced psoriasis by inhibiting Th17 cell immune response and Th17-related cytokine secretion via modulation of the STAT3 signaling pathway.

Porphyromonas gingivalis and Lactobacillus rhamnosus GG regulate the Th17/Treg balance in colitis via TLR4 and TLR2

OBJECTIVES

CD4⁺ T cells are the key to many immune-inflammatory diseases mediated by microbial disorders, especially inflammatory bowel disease (IBD). The purpose of this study was to explore how pathogenic and probiotic bacteria directly affect the T helper (Th)17 and T regulatory (Treg) cell balance among CD4⁺ T cells to regulate inflammation.

METHODS

Porphyromonas gingivalis (Pg; ATCC 33277) and Lactobacillus rhamnosus GG (LGG; CICC 6141) were selected as representative pathogenic and probiotic bacteria, respectively. Bacterial extracts were obtained via ultrasonication and ultracentrifugation. Flow cytometry, RT-qPCR, ELISAs, immunofluorescence and a Quantibody cytokine array were used. The dextran sodium sulphate (DSS)-induced colitis model was selected for verification.

RESULTS

The Pg ultrasonicate induced the apoptosis of CD4⁺ T cells and upregulated the expression of the Th17-associated transcription factor RoRγt and the production of the proinflammatory cytokines IL-17 and IL-6, but downregulated the expression of the essential Treg transcription factor Foxp3 and the production of the anti-inflammatory factors TGF-β and IL-10 via the TLR4 pathway. However, LGG extract maintained Th17/Treg homeostasis by decreasing the IL-17⁺ Th17 proportion and increasing the CD25⁺ Foxp3⁺ Treg proportion via the TLR2 pathway. In vivo, Pg-stimulated CD4⁺ T cells aggravated DSS-induced colitis by increasing the Th17/Treg ratio in the colon and lamina propria lymphocytes (LPLs), and Pg + LGG-stimulated CD4⁺ T cells relieved colitis by decreasing the Th17/Treg ratio via the JAK-STAT signalling pathway.

CONCLUSIONS

Our findings suggest that pathogenic Pg and probiotic LGG can directly regulate the Th17/Treg balance via different TLRs.

Recent advances in gut Microbiota mediated therapeutic targets in inflammatory bowel diseases: Emerging modalities for future pharmacological implications

The inflammatory bowel diseases (IBDs) are chronic inflammatory conditions, which are increasing in prevalence worldwide. The IBDs are thought to result from an aberrant immune response to gut microbes in genetically susceptible individuals. Dysbiosis of the gut microbiome, both functional and compositional, promotes patient susceptibility to colonization by pathobionts. Manipulating gut microbial communities and gut microbiota-immune system interactions to restore gut homeostasis or reduce inflammation are appealing therapeutic models. We discuss the therapeutic potential of precision microbiota editing, natural and engineered probiotics, the use of gut microbiota-derived metabolites in colitogenic phenotypes, and intestinal stem cells, in maintaining gut microbiota balance, restoring the mucosal barrier, and having positive immunomodulatory effects in experimental IBD. This review highlights that we are only just beginning to understand the complexity of the microbiota and how it can be manipulated for health benefits, including treatment and prevention of the clinical IBDs in future.

Role of mTORC1 in intestinal epithelial repair and tumorigenesis

mTORC1 signaling is the prototypical pathway regulating protein synthesis and cell proliferation. mTORC1 is active in stem cells located at the base of intestinal crypts but silenced as transit-amplifying cells differentiate into enterocytes or secretory cells along the epithelium. After an insult or injury, self-limiting and controlled activation of mTORC1 is critical for the renewal and repair of intestinal epithelium. mTORC1 promotes epithelial cell renewal by driving cryptic stem cell division, and epithelial cell repair by supporting the dedifferentiation and proliferation of enterocytes or secretory cells. Under repeated insult or injury, mTORC1 becomes constitutively active, triggering an irreversible return to stemness, cell division, proliferation, and inflammation among dedifferentiated epithelial cells. Epithelium-derived cytokines promulgate inflammation within the lamina propria, which in turn releases inflammatory factors that act back on the epithelium where undamaged intestinal epithelial cells participate in the pervading state of inflammation and become susceptible to tumorigenesis.

Huangkui Lianchang Decoction Ameliorates DSS-Induced Ulcerative Colitis in Mice by Inhibiting the NF-kappaB Signaling Pathway

BACKGROUND

The nuclear factor kappa beta (NF-κB) signaling pathway plays an important role in ulcerative colitis (UC). Huangkui Lianchang decoction (HLD) is an effective traditional Chinese medicinal compound used in the treatment of UC. HLD has good effects in the clinic, but the mechanism by which HLD acts is unclear. This study aims to reveal the exact molecular mechanism of HLD in the treatment of UC.

METHODS

Mouse ulcerative colitis was induced by dextran sulfate sodium (DSS) and treated with HLD. Intestinal damage was assessed by disease activity index (DAI), colon macroscopic lesion scores, and histological scores. Interleukin (IL)-6, tumor necrosis factor (TNF)-α, and IL-1β were detected in colon tissue using ELISA. Myeloperoxidase (MPO) and superoxide dismutase (SOD) activities in the colonic mucosa were measured. The levels of IL-6, inducible nitric oxide synthase (iNOS), and cyclooxygenase-2 (COX-2) in the colon were determined by real-time quantitative polymerase chain reaction (qPCR). The expression of NF-κB, IκBα, and p-IκBα in the colon was measured by Western blot.

RESULTS

After treatment with HLD, the DAI scores, macroscopic lesion scores, and histological scores decreased, and the levels of inflammatory cytokines related to the NF-κB signaling pathway, such as IL-6, TNF-α, and IL-1β, as well as those of iNOS and COX-2, were reduced; at the same time, colonic pathological damage was alleviated, and the MPO and SOD activities decreased. Western blot confirmed that HLD can inhibit the NF-κB signaling pathway in DSS-induced ulcerative colitis.

CONCLUSION

HLD can alleviate the inflammation caused by ulcerative colitis. In particular, high doses of HLD can significantly alleviate intestinal inflammation and have comparable efficacy to Mesalazine. We propose that the anti-inflammatory activity of HLD on DSS-induced colitis in mice may involve the inhibition of the NF-κB pathway.

Beneficial effects of dual TORC1/2 inhibition on chronic experimental colitis

BACKGROUND AND AIM

AZD8055, a new immunosuppressive reagent, a dual TORC1/2 inhibitor, had been used successfully in animal models for heart transplantation. The aim of this study was to evaluate the effects and mechanisms of AZD8055 on chronic intestinal inflammation.

METHODS

Dextran sulfate sodium (DSS) - induced chronic colitis was used to investigate the effects of AZD8055 on the development of colitis. Colitis activity was monitored by body weight assessment, colon length, histology and cytokine profile analysis.

RESULTS

AZD8055 treatment significantly alleviated the severity of colitis, as assessed by colonic length and colonic damage. In addition, AZD8055 treatment decreased the colonic CD4+ T cell numbers and reduced both Th1 and Th17 cell activation and cytokine production. The percentages of Treg cells in the colon were also expanded by AZD8055 treatment. Furthermore, AZD8055 effectively inhibited mTOR downstream proteins and signal transducer and activator of transcription related proteins in CD4+ T cells of intestinal lamina propria.

CONCLUSIONS

These findings increased our understanding of DSS-induced colitis and shed new lights on mechanisms of digestive tract chronic inflammation. Dual TORC1/2 inhibition showed potent anti-inflammatory and immune regulation effects by targeting critical signaling pathways. The results supported the strategy of using dual mTOR inhibitor to treat inflammatory bowel disease.