Selection strategy of dextran sulfate sodium-induced acute or chronic colitis mouse models based on gut microbial profile

Gallic Acid Ameliorated Chronic DSS-Induced Colitis Through Gut Microbiota Modulation, Intestinal Barrier Improvement, and Inflammation

SCOPE

Gallic acid (GA) is recognized for its purported antiinflammatory properties. GA has been demonstrated to prevent and alleviate the symptoms of chronic colitis through the modulation of the gut microbiota, improvement of the intestinal barrier, and reduction of inflammation.

METHODS AND RESULTS

In order to determine the mechanism by which GA exerts its protective effect against chronic colitis, mice were induced by dextran sulfate sodium (DSS). The reduction in the disease activity index by 25% and the decrease in colon tissue damage indicated that 36 days of GA intervention alleviated chronic DSS-induced colitis symptoms. GA was observed to mitigate weight loss by 2.5% and the shortening of colon by 17.3%, and to diminish the expression of pivotal proteins within the TLR4/nuclear factor κB (NF-κB) signaling cascades, consequently lowering the generation of inflammatory cytokines. Furthermore, GA effectively corrected the gut microbiota imbalance, increased the content of short-chain fatty acids (SCFAs), which in turn suppressed inflammation, and enhanced tight junction protein expression, thereby strengthening the intestinal barrier.

CONCLUSION

GA has the capacity to enhance the efficacy of chronic colitis through a multifaceted mechanism, influencing the gut microbiota, intestinal barrier function, and inflammatory processes. The findings highlight the potential of GA as a preventative strategy for chronic colitis.

Plasma Lipidomics, Gut Microbiota Profile, and Phenotype of Adipose Tissue in an ApoE-/- Mouse Model of Plaque Instability

BACKGROUND

An appropriate animal model that can simulate the pathological process of atherosclerosis is urgently needed to improve treatment strategies. This study aimed to develop a new atherosclerosis model using ApoE-/- mice and to characterize lipidomics, gut microbiota profiles, and phenotypic alterations in adipose tissue using this model.

METHODS

After a 14- or 18-week high-fat diet (HFD), male ApoE-/- mice were randomly divided into four groups and treated separately with or without short-term and strong co-stimulation, including ice water bath and intraperitoneal injection of lipopolysaccharide and phenylephrine. As a control group, C57BL/6 mice were fed with conventional chow. The serum lipid levels, aortic arch pathology, adipose tissue phenotypic changes, plasma lipidomics, and 16S rDNA gene sequencing of colon feces were investigated.

RESULTS

The serum lipid levels were significantly lowered following extended HFD feeding for four weeks. However, co-stimulation increased serum interleukin (IL)-1β levels but did not affect serum lipid profiles. Co-stimulation revealed typical vulnerable atherosclerotic plaque characteristics and defective adipose hypertrophy associated with peroxisome proliferator-activated receptor γ (PPARγ) regulation in adipose tissue and a reduction in mitochondrial uncoupling protein 1 (UCP1) within brown adipose tissue. Plasma lipidomic analysis showed that sphingomyelin (SM), ceramide (Cer), and monohexosylceramide (HexCer) levels in plasma were significantly elevated by HFD feeding, whereas co-stimulation further elevated HexCer levels. Additionally, glycerophosphocholines (16:0/16:0, 18:2/20:4, 18:1/18:1) and HexCer (C12:1, C16:0), Cer (d18:1/16:0), and SM (C16:0) were the most sensitive to co-stimulation. Combined co-stimulation and HFD-fed increased the abundance of Firmicutes, the abundance of f_Erysipelotrichaceae, and the Firmicutes/Bacteroidota ratio but decreased the abundance of microflora promoting bile acid metabolism and short-chain fatty acids (SCFAs) in mouse feces. The results were consistent with the findings of epidemiologic atherosclerotic cardiovascular disease studies.

CONCLUSIONS

This study established an ApoE-/- mouse atherosclerotic vulnerable plaque model using a multi-index evaluation method. Adipogenic disorders, dysregulation of lipid metabolism at the molecular level, and increasing harmful gut microbiota are significant risk factors for vulnerable plaques, with sphingolipid metabolism receiving the most attention.

Early-life antibiotic exposure aggravates hepatic steatosis through enhanced endotoxemia and lipotoxic effects driven by gut Parabacteroides

Compelling evidence supports a link between early-life gut microbiota and the metabolic outcomes in later life. Using an early-life antibiotic exposure model in BALB/c mice, we investigated the life-course impact of prenatal and/or postnatal antibiotic exposures on the gut microbiome of offspring and the development of metabolic dysfunction-associated steatotic liver disease (MASLD). Compared to prenatal antibiotic exposure alone, postnatal antibiotic exposure more profoundly affected gut microbiota development and succession, which led to aggravated endotoxemia and metabolic dysfunctions. This was primarily resulted from the overblooming of gut Parabacteroides and hepatic accumulation of cytotoxic lysophosphatidyl cholines (LPCs), which acted in conjunction with LPS derived from Parabacteroides distasonis (LPS_PA) to induce cholesterol metabolic dysregulations, endoplasmic reticulum (ER) stress and apoptosis. Integrated serum metabolomics, hepatic lipidomics and transcriptomics revealed enhanced glycerophospholipid hydrolysis and LPC production in association with the upregulation of PLA2G10, the gene controlling the expression of the group X secretory Phospholipase A2s (sPLA2-X). Taken together, our results show microbial modulations on the systemic MASLD pathogenesis and hepatocellular lipotoxicity pathways following early-life antibiotic exposure, hence help inform refined clinical practices to avoid any prolonged maternal antibiotic administration in early life and potential gut microbiota-targeted intervention strategies.

Camel Milk Protein Ameliorates Ulcerative Colitis by Modulating Gut Microbiota and Amino Acid Metabolism

The protective effects of the milk fat globule membrane (MFGM) in alleviating inflammation have been reported. However, limited attention has been paid to the key fraction of milk fat globule membrane protein (MFGMP). This study investigated the protective effects of camel MFGMP against dextran sulfate sodium (DSS)-induced ulcerative colitis (UC) in mice. The results revealed that administering 50 mg/kg MFGMP significantly alleviated colonic inflammation, as evidenced by a marked decrease in IL-6, IL-1β, and TNF-α levels, along with pathological damage in DSS-induced mice with UC. MFGMP supplementation partially regulated gut microbiota dysbiosis in mice with UC by increasing α-diversity and the relative abundance of beneficial gut bacteria, such as Lactobacillus, while decreasing the abundance of Akkermansia. Additionally, MFGMP treatment exhibited significant regulatory effects on metabolites, particularly amino acid metabolism, in the feces. Specifically, this treatment restored L-valine to normal physiological levels and increased the concentrations of L-leucine, L-lysine, and L-tyrosine to nearly twice their baseline levels, whereas the concentration of L-tryptophan increased threefold. These upregulated amino acids were negatively correlated with pro-inflammatory cytokines and positively correlated with the anti-inflammatory cytokine IL-10, as indicated by Spearman's correlation analysis. Furthermore, the significant reduction in the mRNA expression levels of WNT-1, β-catenin, and Cyclin D1 suggests that MFGMP exerts a positive effect on UC via the Wnt/β-catenin pathway. These findings indicate that MFGMP exerts a protective effect against UC by modulating intestinal microbiota and amino acid metabolism in mice, with potential implications for treating intestinal inflammatory diseases.

Eisenia bicyclis Extract Ameliorates Colitis in In Vitro and In Vivo Models Through Modulation of mTOR Axis and Gut Microbiota Composition

Ulcerative colitis (UC) is a chronic inflammatory disease of the colon that is associated with dysbiosis in the gut microbiota. Eisenia bicyclis, a marine alga, is known for its anti-inflammatory, antioxidant, and gut microbiota-modulating properties. This study explored the mechanisms by which a 70% ethanol extract of E. bicyclis may alleviate UC, through both in vitro and in vivo experiments. LC-MS/MS analysis revealed eckol, 7-phloroeckol, dieckol, phlorofucofuroeckol A, and fucofuroeckol as key phenolic compounds present in the extract. The administration of E. bicyclis significantly improved symptoms in a dextran sulfate sodium (DSS)-induced colitis mouse model by reducing intestinal shortening, splenomegaly, and histological scores. Both cell and animal studies demonstrated that E. bicyclis suppressed the release of inflammatory cytokines, downregulated the mRNA expression of genes related to the mTOR pathway, and reduced the p-mTOR/mTOR ratio. Microbiota analysis revealed that, while the Firmicutes/Bacteroidetes ratio was elevated in UC mice, E. bicyclis administration normalized this imbalance, with a notable increase in the abundance of beneficial probiotics such as Bifidobacterium bifidum. In conclusion, a phenolic-rich extract of E. bicyclis demonstrates significant potential as a dietary supplement to prevent and mitigate UC by modulating both the mTOR signaling pathway and gut microbiota composition.

Bisdemethoxycurcumin and Curcumin Alleviate Inflammatory Bowel Disease by Maintaining Intestinal Epithelial Integrity and Regulating Gut Microbiota in Mice

Curcuminoids, found in turmeric (Curcuma longa L.), include curcumin (CUR), demethoxycurcumin (DMC), and bisdemethoxycurcumin (BDMC). Although CUR and DMC are well-studied, the anti-inflammatory effects of BDMC remain less explored. Recent studies highlight BDMC's stronger NF-κB inhibition compared to CUR and DMC in cell models, along with its ability to target pathways associated with inflammatory bowel disease (IBD) in DSS-induced colitis mice, reflected by lower disease activity scores and reduced inflammation. This study assessed CUR and BDMC in a DSS-induced colitis mouse model. Dietary administration of CUR or BDMC strengthened tight junction (TJ) proteins, reduced inflammatory cytokine secretion, and attenuated intestinal inflammatory protein expression, thereby alleviating DSS-induced IBD in mice. Furthermore, gut microbiota and short-chain fatty acid analyses revealed that CUR and BDMC effectively regulated gut microbial imbalance and promoted the relative abundance of butyrate-producing bacteria. Furthermore, CUR showed low absorption and was primarily excreted in feces, while BDMC had higher absorption levels. In conclusion, while both BDMC and CUR have potential as adjunct therapies for IBD, BDMC at a concentration of 0.1% showed strong anti-inflammatory effects and enhanced TJ proteins, suggesting that BDMC, even at lower concentrations than CUR, holds promising therapeutic potential and prospects.

Mannuronate Oligosaccharides Ameliorate Experimental Colitis and Secondary Neurological Dysfunction by Manipulating the Gut-Brain Axis

Microbiota dysfunction induces intestinal disorders and neurological diseases. Mannuronate oligosaccharides (MAOS), a kind of alginate oligosaccharide (AOS), specifically exert efficacy in shaping gut microbiota and relieving cognitive impairment. However, the key regulatory factors involved, such as the specific strains and metabolites as well as their regulatory mechanisms, remain unclear at present. This research investigates how MAOS specifically impact the gut-brain axis in vivo and in vitro. The results showed that pretreatment with MAOS significantly ameliorated dextran sodium sulfate (DSS)-induced colitis and secondary nerve injury. This preventive mechanism operates through the regulation of serum DOPC abundance and the gut-brain axis, achieved by inhibiting the TLR4/MyD88/NF-κB pathway. These findings underscore the crucial role of dietary MAOS in the prevention of colitis and neurological disorders, providing a rationale for the application of MAOS in disease prevention and functional food ingredients.

Wheat β-glucan reduces obesity and hyperlipidemia in mice with high-fat and high-salt diet by regulating intestinal flora

Unbalanced diets, characterized by high fat or high salt content, are contributing to the obesity epidemic. Wheat bran, recognized as a promising by-product, has the potential to regulate metabolic disorders (MD) associated with obesity. Beta-glucan (BG) has multiple biological activities, but the effect of BG in wheat bran on MD remains unclear. Therefore, this study aimed to investigate the effects of wheat BG (WBG) on dyslipidemia and gut microbiota dysregulation in high fat (HF) or high fat-high salt (HFHS) fed mice. The results demonstrated that WBG significantly reduced the weight gain of mice fed with HF and HFHS diets (from 9.74 g to 2.43 g and from 6.74 g to 2.48 g, respectively). Additionally, WBG led to significant reductions in TG (26.26 % in HFG and 33.78 % in HFHSG) and TC (34.69 % in HFG) levels. The liver and adipocyte damage were also reduced after dietary supplementation with WBG. Moreover, WBG significantly reduced Firmicutes/Bacteroidetes ratio (9.52 at HF, 0.62 at HFG, 17.38 at HFHS and 0.61 at HFHSG). Concurrently, there was a reduction in acetic acid levels observed at rates of 26.11 % for HF and 32.18 % for HFHS. Additionally, WBG reduced the abundance of Coriobacteriaceae UCG-002, Romboutsia, Faecalibaculum, and Enterorhabdus that positively associated with obesity. These changes in gut microbiota may explain the anti-obesity and anti-hyperlipidemia effects of WBG. In conclusion, our findings suggest that WBG is a promising dietary supplement. Our research can provide new insights into the development of foods rich in dietary fiber.

Dextran sodium sulfate-induced colitis alters the proportion and composition of replicating gut bacteria

The bacteria living in the human gut are essential for host health. Though the composition and metabolism of these bacteria are well described in both healthy hosts and those with intestinal disease, less is known about the metabolic activity of the gut bacteria prior to, and during, disease development-especially regarding gut bacterial replication. Here, we use a recently developed single-cell technique alongside existing metagenomics-based tools to identify, track, and quantify replicating gut bacteria both ex vivo and in situ in the dextran sodium sulfate (DSS) mouse model of colitis. We show that the proportion of replicating gut bacteria decreases when mice have the highest levels of inflammation and returns to baseline levels as mice begin recovering. In addition, we report significant alterations in the composition of the replicating gut bacterial community ex vivo during colitis development. On the taxa level, we observe significant changes in the abundance of taxa such as the mucus-degrading Akkermansia and the poorly described Erysipelatoclostridium genus. We further demonstrate that many taxa exhibit variable replication rates in situ during colitis, including Akkermansia muciniphila. Lastly, we show that colitis development is positively correlated with increases in the presence and abundance of bacteria in situ which are predicted to be fast replicators. This could suggest that taxa with the potential to replicate quickly may have an advantage during intestinal inflammation. These data support the need for additional research using activity-based approaches to further characterize the gut bacterial response to intestinal inflammation and its consequences for both the host and the gut microbial community.IMPORTANCEIt is well known that the bacteria living inside the gut are important for human health. Indeed, the type of bacteria that are present and their metabolism are different in healthy people versus those with intestinal disease. However, less is known about how these gut bacteria are replicating, especially as someone begins to develop intestinal disease. This is particularly important as it is thought that metabolically active gut bacteria may be more relevant to health. Here, we begin to address this gap using several complementary approaches to characterize the replicating gut bacteria in a mouse model of intestinal inflammation. We reveal which gut bacteria are replicating, and how quickly, as mice develop and recover from inflammation. This work can serve as a model for future research to identify how actively growing gut bacteria may be impacting health, or why these particular bacteria tend to thrive during intestinal inflammation.

Gut bacteria Prevotellaceae related lithocholic acid metabolism promotes colonic inflammation

BACKGROUND

The conversion of primary bile acids to secondary bile acids by the gut microbiota has been implicated in colonic inflammation. This study investigated the role of gut microbiota related bile acid metabolism in colonic inflammation in both patients with inflammatory bowel disease (IBD) and a murine model of dextran sulfate sodium (DSS)-induced colitis.

METHODS

Bile acids in fecal samples from patients with IBD and DSS-induced colitis mice, with and without antibiotic treatment, were analyzed using ultraperformance liquid chromatography-mass spectrometry (UPLC-MS). The composition of the microbiota in fecal samples from IBD patients and DSS-colitis mice was characterized via Illumina MiSeq sequencing of the bacterial 16S rRNA gene V3-V4 region. Metagenomic profiling further identified metabolism-related gene signatures in stool samples from DSS-colitis mice. Histological analysis, quantitative PCR (qPCR) and Western Blotting were conducted on colonic samples from DSS-induced colitis mice to assess colonic inflammation, mucosal barrier integrity, and associated signaling pathways. The multivariate analysis of bile acids was conducted using Soft Independent Modelling of Class Analogy (SIMCA, Umetrics, Sweden). The relation between the relative abundance of specific phyla/genera and bile acid concentration was assess through Spearman's correlation analyses. Finally, lithocholic acid (LCA), the key bile acid, was administered via gavage to evaluate its effect on colonic inflammation and mucosal barrier integrity.

RESULTS

In patients with IBD, the composition of colonic bile acids and gut microbiota was altered. Moreover, changes in the gut microbiota further modulate the composition of bile acids in the intestine. As the gut microbiota continues to shift, the bile acid profile undergoes additional alterations. The aforementioned alterations were also observed in mice with DSS-induced colitis. The study revealed a correlation between dysbiosis of the gut microbiota and modifications in the profile of colonic bile acids, notably LCA observed in both patients with IBD and mice with DSS-induced colitis. Through multivariate analysis, LCA was identified as the key bile acid that significantly affects colonic inflammation and the integrity of mucosal barrier. Subsequent experiments confirmed that LCA supplementation effectively mitigated the inhibitory effects of gut microbiota on colitis progression in mice, primarily through the activation of the sphingosine-1-phosphate receptor 2 (S1PR2)/NF-κB p65 signaling pathway. Analysis of the microbiome and metagenomic data revealed changes in the gut microbiota, notably an increased abundance of an unclassified genus within the family Prevotellaceae in DSS-induced colitis mice. Furthermore, a positive correlation was observed between the relative abundance of Prevotellaceae and bile acid biosynthesis pathways, as well as colonic LCA level.

CONCLUSIONS

These findings suggest that LCA and its positively correlated gut bacteria, Prevotellaceae, are closely associated with intestinal inflammation. Targeting colonic inflammation may involve inhibiting LCA and members of the Prevotellaceae family as potential therapeutic strategies.

Blood pressure alteration associated with abnormal body electrolyte and water balance in colitis mice

Previous studies reported that there is an association between abnormal body fluid balance and prognosis in colitis patients. However, it remains to be clarified the effects of colitis on characteristics of body electrolytes or water content, including alternation in blood pressure. In this study, we examined the effects of colon injury on body water balance and blood pressure in the dextran sodium sulfate (DSS)-induced colitis mouse model. We evaluated body electrolytes and water content, blood pressure, and urea-associated water conservation in DSS mice. By 5 days after the treatment, DSS mice exhibited diarrhea but relatively maintained body weight and total body sodium, potassium, and water content by increases in water intake and hepatic ureagenesis. On 7 days after DSS treatment, when colitis becomes severe, DSS mice significantly decreased food and water intake, and body weight but significantly increased relative total body sodium, potassium, and water content per dry mass. Notably, DSS induced more total body dry mass loss relative to water loss. These body electrolytes and water accumulation on day 7 were associated with a reduction in urinary osmole excretion and urine volume accompanied by renal urea accumulation. DSS mice significantly increased blood pressure by day 5 and then decreased on day 7. These findings suggest that body electrolyte and fluid imbalance and alternations in blood pressure in colitis vary with the stage and severity of the condition. Assessment and correction of electrolyte and water content at the tissue level would be important to improve the prognosis of colitis.

Lacticaseibacillus rhamnosus LRa05 mediates dynamic regulation of intestinal microbiota in mice with low-dose DSS-induced chronic mild inflammation

Aim

This study aimed to investigate the effects of low-dose dextran sulfate sodium (DSS) on the induction of chronic mild inflammation in mice and to evaluate the therapeutic potential of Lacticaseibacillus rhamnosus LRa05 (LRa05) to ameliorate the associated effects. The focus was on investigating changes in inflammatory, gut microbiota, serum lipopolysaccharide (LPS) and inflammatory cytokines.

Methods

Mice were exposed to a low-dose of DSS to induce chronic mild inflammation and LRa05 was administered as a probiotic intervention. The experiment included determination of body weight, colon length, histological examinations, and analysis of LPS and inflammatory cytokines in serum over 12 weeks. In addition, liver function, oxidative stress and intestinal microbiota were examined to understand the comprehensive effects of DSS and LRa05.

Results

Low-dose DSS did not lead to significant changes in body weight, colon length or histologic signs of inflammation. However, it led to a significant increase in serum levels of LPS, tumor necrosis factor-alpha (TNFα) and interleukin-6 (IL6). Intervention with LRa05 effectively attenuated these changes, particularly by lowering LPS levels and normalizing inflammatory cytokines. In addition, LRa05 protected against DSS-induced liver function damage and attenuated oxidative stress in the liver. Analysis of the gut microbiota demonstrated dynamic regulatory effects, where LRa05 intervention led to significant shifts in microbial populations, promoting a balanced microbiota profile. These changes are indicative of dynamic regulation by LRa05 in response to chronic mild inflammation, highlighting the probiotic's role in modulating the gut environment.

Conclusion

The LRa05 intervention showed multi-layered regulation in the chronic mild inflammation model by reducing inflammatory cytokines, maintaining liver function and restoring the balance of the gut microbiota. This provides experimental support for the potential use of LRa05 in chronic inflammation-related diseases and emphasizes the importance of probiotics for overall health. The study suggests that LRa05 is a potential therapeutic agent for the treatment of chronic inflammation associated with gut dysbiosis.

Functional evaluation of pure natural edible Ferment: protective function on ulcerative colitis

Purpose

To investigate the therapeutic efficiency of a novel drink termed "Ferment" in cases of ulcerative colitis (UC) and its influence on the gut microbiota.

Method

In this study, we developed a complex of mixed fruit juice and lactic acid bacteria referred to as Ferment. Ferment was fed to mice for 35 days, before inducing UC with Dextran Sulfate Sodium Salt. We subsequently investigated the gut microbiome composition using 16S rRNA sequencing.

Result

After Ferment treatment, mouse body weight increased, and animals displayed less diarrhea, reduced frequency of bloody stools, and reduced inflammation in the colon. Beneficial bacteria belonging to Ileibacterium, Akkermansia, and Prevotellacea were enriched in the gut after Ferment treatment, while detrimental organisms including Erysipelatoclostridium, Dubosiella, and Alistipes were reduced.

Conclusion

These data place Ferment as a promising dietary candidate for enhancing immunity and protecting against UC.

Yerba Mate (Ilex paraguariensis) Reduces Colitis Severity by Promoting Anti-Inflammatory Macrophage Polarization

Yerba Mate (YM) (Ilex paraguariensis) is a natural herbal supplement with a well-described anti-inflammatory capacity and beneficial effects in different inflammatory contexts such as insulin resistance or obesity. However, whether YM could improve other inflammatory conditions such as colitis or the immune cell population that can be modulated by this plant remains elusive. Here, by using 61 male and female C57BL/6/J wild-type (WT) mice and the dextran sodium sulfate (DSS)-induced acute colitis model, we evaluated the effect of YM on colitis symptoms and macrophage polarization. Our results showed that the oral administration of YM reduces colitis symptoms and improves animal survival. Increasing infiltration of anti-inflammatory M2 macrophage was observed in the colon of the mice treated with YM. Accordingly, YM promoted M2 macrophage differentiation in vivo. However, the direct administration of YM to bone marrow-derived macrophages did not increase anti-inflammatory polarization, suggesting that YM, through an indirect mechanism, is able to skew the M1/M2 ratio. Moreover, YM consumption reduced the Eubacterium rectale/Clostridium coccoides and Enterobacteriaceae groups and increased the Lactobacillus/Lactococcus group in the gut microbiota. In summary, we show that YM promotes an immunosuppressive environment by enhancing anti-inflammatory M2 macrophage differentiation, reducing colitis symptoms, and suggesting that YM consumption may be a good cost-effective treatment for ulcerative colitis.

Dual engineered bacteria improve inflammatory bowel disease in mice

Currently, there are many different therapies available for inflammatory bowel disease (IBD), including engineered live bacterial therapeutics. However, most of these studies focus on producing a single therapeutic drug using individual bacteria, which may cause inefficacy. The use of dual drugs can enhance therapeutic effects. However, expressing multiple therapeutic drugs in one bacterial chassis increases the burden on the bacterium and hinders good secretion and expression. Therefore, a dual-bacterial, dual-drug expression system allows for the introduction of two probiotic chassis and enhances both therapeutic and probiotic effects. In this study, we constructed a dual bacterial system to simultaneously neutralize pro-inflammatory factors and enhance the anti-inflammatory pathway. These bacteria for therapy consist of Escherichia coli Nissle 1917 that expressed and secreted anti-TNF-α nanobody and IL-10, respectively. The oral administration of genetically engineered bacteria led to a decrease in inflammatory cell infiltration in colon and a reduction in the levels of pro-inflammatory cytokines. Additionally, the administration of engineered bacteria did not markedly aggravate gut fibrosis and had a moderating effect on intestinal microbes. This system proposes a dual-engineered bacterial drug combination treatment therapy for inflammatory bowel disease, which provides a new approach to intervene and treat IBD. KEY POINTS: • The paper discusses the effects of using dual engineered bacteria on IBD • Prospects of engineered bacteria in the clinical treatment of IBD.

Unveiling Colitis: A Journey through the Dextran Sodium Sulfate-induced Model

Animal models of inflammatory bowel disease (IBD) are valuable tools for investigating the factors involved in IBD pathogenesis and evaluating new therapeutic options. The dextran sodium sulfate (DSS)-induced model of colitis is arguably the most widely used animal model for studying the pathogenesis of and potential treatments for ulcerative colitis (UC), which is a primary form of IBD. This model offers several advantages as a research tool: it is highly reproducible, relatively easy to generate and maintain, and mimics many critical features of human IBD. Recently, it has also been used to study the role of gut microbiota in the development and progression of IBD and to investigate the effects of other factors, such as diet and genetics, on colitis severity. However, although DSS-induced colitis is the most popular and flexible model for preclinical IBD research, it is not an exact replica of human colitis, and some results obtained from this model cannot be directly applied to humans. This review aims to comprehensively discuss different factors that may be involved in the pathogenesis of DSS-induced colitis and the issues that should be considered when using this model for translational purposes.

Effect of Enteromorpha polysaccharides on gut-lung axis in mice infected with H5N1 influenza virus

Enteromorpha polysaccharides (EPPs) have been reported to have antiviral and anti-inflammatory properties. To explore the effect of EPPs on H5N1-infected mice, mice were pretreated with EPPs before being infected with the H5N1 influenza virus intranasally. H5N1 infection resulted in body-weight loss, pulmonary and intestinal damage, and an imbalance of gut microbiota in mice. As a result of the inclusion of EPPs, the body weight of mice recovered and pathological damage to the lung and intestine was reduced. EPPs also diminished inflammation by drastically lowering the expression of proinflammatory cytokines in lungs and intestines. H5N1 infection reduced bacterial diversity, and the abundance of pathogenic bacteria such as Desulfovibrio increased. However, the beneficial bacteria Alistipes rebounded in the groups which received EPPs before the infection. The modulation of the gut-lung axis may be related to the mechanism of EPPs in antiviral and anti-inflammatory responses. EPPs have shown potential in protecting the host from the influenza A virus infection.

New insights into the interactions between the gut microbiota and the inflammatory response to ulcerative colitis in a mouse model of dextran sodium sulfate and possible mechanisms of action for treatment with PE&AFWE

BACKGROUND

Inflammatory bowel disease (IBD), comprising Crohn's disease (CD) and ulcerative colitis (UC), is a heterogeneous state of chronic intestinal inflammation. Intestinal innate immunity, including innate immune cells, defends against pathogens and excessive entry of gut microbiota, while preserving immune tolerance to resident intestinal microbiota, and may be characterized by its capacity to produce a rapid and nonspecific reaction. The association between microbiota dysbiosis and the pathogenesis of IBD is complex and dynamic. When the intestinal ecosystem is in dysbiosis, the reduced abundance and diversity of intestinal gut microbiota make the host more vulnerable to the attack of exogenous and endogenous pathogenic gut microbiota. The aim of our study was to comprehensively assess the relationship between microbial populations within UC, the signaling pathways of pathogenic gut microbe therein and the inflammatory response, as well as to understand the effects of using PE&AFWE (poppy extract [Papaver nudicaule L.] and Artemisia frigida Willd. extract) on UC modulation.

METHODS

A UC mouse model was established by inducing SPF-grade C57BL/6 mice using dextrose sodium sulfate (DSS). Based on metagenomic sequencing to characterize the gut microbiome, the relationship between gut microbiota dysbiosis and gut microbiota was further studied using random forest and Bayesian network analysis methods, as well as histopathological analysis.

RESULTS

(1) We found that the 5 gut microbiota with the highest relative abundance of inflammatory bowel disease UC model gut microbiota were consistent with the top 5 ranked natural bacteria. There were three types of abundance changes in the model groups: increases (Chlamydiae/Proteobacteria and Deferribacteres), decreases (Firmicutes), and no significant changes (Bacteroidetes). The UC model group was significantly different from the control group, with 1308 differentially expressed species with abundance changes greater than or equal to 2-fold. (2) The proportion of the fecal flora in the UC group decreased by 37.5% in the Firmicutes and increased by 14.29% in the proportion of Proteobacteria compared to the control group before treatment. (3) The significantly enriched and increased signaling pathways screened were the 'arachidonic acid metabolic pathway' and the 'phagosomal pathway', which both showed a decreasing trend after drug administration. (4) Based on the causal relationship between different OTUs and the UC model/PE&AFWE administration, screening for directly relevant OTU networks, the UC group was found to directly affect OTU69, followed by a cascade of effects on OTU12, OTU121, OTU93, and OTU7, which may be the pathway of action that initiated the pathological changes in normal mice. (5) We identified a causal relationship between common differentially expressed OTUs and PE&AFWE and UC in the pre- and post-PE&AFWE-treated groups. Thereby, we learned that PE&AFWE can directly affect OTU90, after which it inhibits UC, inhibiting the activity of arachidonic acid metabolic pathway by affecting OTU118, which in turn inhibits the colonization of gut microbiota by OTU93 and OTU7. (6) Histopathological observation and scoring (HS) of the colon showed that there was a significant difference between the model group and the control group (p < 0.001), and that there was a significant recovery in both the sulfasalazine (SASP)and the PE&AFWE groups after the administration of the drug (p < 0.0001).

CONCLUSION

We demonstrated causal effects and inflammatory metabolic pathways in gut microbiota dysbiosis and IBD, with five opportunistic pathogens directly contributing to IBD. PE&AFWE reduced the abundance of proteobacteria in the gut microbiota, and histopathology showed significant improvement.

Enhancing tumor-specific recognition of programmable synthetic bacterial consortium for precision therapy of colorectal cancer

Probiotics hold promise as a potential therapy for colorectal cancer (CRC), but encounter obstacles related to tumor specificity, drug penetration, and dosage adjustability. In this study, genetic circuits based on the E. coli Nissle 1917 (EcN) chassis were developed to sense indicators of tumor microenvironment and control the expression of therapeutic payloads. Integration of XOR gate amplify gene switch into EcN biosensors resulted in a 1.8-2.3-fold increase in signal output, as confirmed by mathematical model fitting. Co-culturing programmable EcNs with CRC cells demonstrated a significant reduction in cellular viability ranging from 30% to 50%. This approach was further validated in a mouse subcutaneous tumor model, revealing 47%-52% inhibition of tumor growth upon administration of therapeutic strains. Additionally, in a mouse tumorigenesis model induced by AOM and DSS, the use of synthetic bacterial consortium (SynCon) equipped with multiple sensing modules led to approximately 1.2-fold increased colon length and 2.4-fold decreased polyp count. Gut microbiota analysis suggested that SynCon maintained the abundance of butyrate-producing bacteria Lactobacillaceae NK4A136, whereas reducing the level of gut inflammation-related bacteria Bacteroides. Taken together, engineered EcNs confer the advantage of specific recognition of CRC, while SynCon serves to augment the synergistic effect of this approach.

Microbial dysbiosis index for assessing colitis status in mouse models: A systematic review and meta-analysis

Although countless gut microbiome studies on colitis using mouse models have been carried out, experiments with small sample sizes have encountered reproducibility limitations because of batch effects and statistical errors. In this study, dextran-sodium-sulfate-induced microbial dysbiosis index (DiMDI) was introduced as a reliable dysbiosis index that can be used to assess the state of microbial dysbiosis in DSS-induced mouse models. Meta-analysis of 189 datasets from 11 independent studies was performed to construct the DiMDI. Microbial dysbiosis biomarkers, Muribaculaceae, Alistipes, Turicibacter, and Bacteroides, were selected through four different feature selection methods and used to construct the DiMDI. This index demonstrated a high accuracy of 82.3% and showed strong robustness (88.9%) in the independent cohort. Therefore, DiMDI may be used as a standard for assessing microbial imbalance in DSS-induced mouse models and may contribute to the development of reliable colitis microbiome studies in mouse experiments.

Effects of Sichuan pepper (huājiāo) powder on disease activity and caecal microbiota of dextran sodium sulphate-induced inflammatory bowel disease mouse model

BACKGROUND

Sichuan pepper [Zanthoxylum bungeanum; huājiāo (HJ)] is a widely used spice in China and has better antioxidative, anti-glycation, and bile acid-lowering properties than cumin and coriander seeds. HJ affects inflammation-related cytokines and caecal microbiota in mice fed a low-fibre and high-sucrose diet.

METHODS AND RESULTS

To determine the ameliorative effect of HJ on inflammatory bowel disease, C57BL/6 mice were divided into three groups and fed distilled water (control) or 3% (w/v) dextran sodium sulphate (DSS) in drinking water with normal chow containing 0% or 5% (w/w) HJ powder for seven days. After 6 days of feeding, diarrhoea, decreased body weight, and blood in faeces were observed in the DSS group. DSS treatment increased the spleen weight and damaged the colon tissue. These inflammatory indices were inhibited by HJ treatment. Amplicon sequencing of the 16S rDNA (V4) gene of the caecal content revealed a decrease in the alpha diversity (Simpson index D) in the DSS treatment group compared to the control group. The abundance of caecal Desulfovibrio, an inflammation-related genus, was higher and the caecal Lachnospiraceae and Bacteroides levels were lower in the DSS-treated mice than those in the control mice. However, HJ suppressed the DSS-induced changes in the caecal microbiota.

CONCLUSION

HJ intake contributes to the reduction in inflammation and maintenance of the gut microbiota. However, the strong antioxidant properties of phenolic compounds and fermentability of water-soluble dietary fibres in HJ and their relationship with other functional properties warrant further investigation.

Post-Finasteride Syndrome And Post-Ssri Sexual Dysfunction: Two Clinical Conditions Apparently Distant, But Very Close

Post-finasteride syndrome and post-SSRI sexual dysfunction, are two poorly explored clinical conditions in which men treated for androgenetic alopecia with finasteride or for depression with SSRI antidepressants show persistent side effects despite drug suspension (e.g., sexual dysfunction, psychological complaints, sleep disorders). Because of some similarities in the symptoms, common pathological mechanisms are proposed here. Indeed, as discussed, clinical studies and preclinical data obtained so far suggest an important role for brain modulators (i.e., neuroactive steroids), neurotransmitters (i.e., serotonin, and cathecolamines), and gut microbiota in the context of the gut-brain axis. In particular, the observed interconnections of these signals in these two clinical conditions may suggest similar etiopathogenetic mechanisms, such as the involvement of the enzyme converting norepinephrine into epinephrine (i.e., phenylethanolamine N-methyltransferase). However, despite the current efforts, more work is still needed to advance the understanding of these clinical conditions in terms of diagnostic markers and therapeutic strategies.

Omics analysis of the effect of cold normal saline stress through gastric gavage on LPS induced mice

Cold stress is a significant environmental stimulus that negatively affects the health, production, and welfare of animals and birds. However, the specific effects of cold stimulation combined with lipopolysaccharide (LPS) on the mouse intestine remain poorly understood. Therefore, we designed this research to explore the effect of cold stimulation + LPS on mice intestine via microbiome and microbiota sequencing. Forty-eight mice were randomly divided into four experimental groups (n = 12): Control (CC), LPS-induced (CL), cold normal saline-induced (MC) and LPS + cold normal saline-induced (ML). Our results showed body weight was similar among different groups of mice. However, the body weight of mice in groups CC and CL were slightly higher compared to those in groups MC and ML. The results of gene expressions reflected that CL and ML exposure caused gut injury and barrier dysfunction, as evident by decreased ZO-1, OCCLUDIN (P < 0.01), and CASPASE-1 (P < 0.01) expression in the intestine of mice. Moreover, we found that cold stress induced oxidative stress in LPS-challenged mice by increasing malondialdehyde (MDA) accumulation and decreasing the antioxidant capacity [glutathione peroxidase (GSH-Px), superoxide dismutase (SOD), total and antioxidant capacity (T-AOC)]. The cold stress promoted inflammatory response by increased IL-1β in mice treated with cold normal saline + LPS. Whereas, microbiome sequencing revealed differential abundance in four phyla and 24 genera among the mouse groups. Metabolism analysis demonstrated the presence of 4,320 metabolites in mice, with 43 up-regulated and 19 down-regulated in CC vs. MC animals, as well as 1,046 up-regulated and 428 down-regulated in ML vs. CL animals. It is Concluded that cold stress enhances intestinal damage by disrupting the balance of gut microbiota and metabolites, while our findings contribute in improving management practices of livestock in during cold seasons.

Acid-base transformative HADLA micelles alleviate colitis by restoring adaptive immunity and gut microbiome

Inflammatory bowel disease (IBD) is a worldwide public health issue with an increasing number of patients annually. However, there is no curative drug for IBD, and the present medication for IBD generally focuses on suppressing hyperactive immune responses, which can only delay disease progression but inevitably induce off-target side effects, including infections and cancers. Herein, late-model orally administered nanotherapeutic micelles (HADLA) were developed based on a conjugate of hyaluronic acid (HA) and dehydrolithocholic acid (DLA), which was simple to achieve and obtained satisfactory therapeutic efficacy in a murine colitis model with a full safety profile. HADLA is capable of targeting inflammatory colon tissues, restoring intestinal barrier function and reducing intestinal epithelial cell death. Moreover, it modulates the adaptive immune system by inhibiting the activation of pathogenic T helper 17 (Th17) cells, and it exhibits more remarkable effects in preventing colitis than DLA alone. Finally, HADLA exhibits a remarkable ability to modulate dysregulated gut microbiomes by increasing beneficial probiotics and decreasing pathogenic bacteria, such as Turicibacter. Compared with the current systemic or subcutaneous administration of biologics, this study opens new avenues in the oral delivery of immune-modulating nanomedicine and introduces DLA as a new medication for IBD treatment.

Phenolics from Dendrobium officinale Leaf Ameliorate Dextran Sulfate Sodium-Induced Chronic Colitis by Regulating Gut Microbiota and Intestinal Barrier

The increasing incidence of colitis and the side effects of its therapeutic drugs have led to the search for compounds of natural origin, including phenolics, as new treatments for colitis. In this study, the potential mechanism of Dendrobium officinale leaf phenolics (DOP) on the relief of dextran sulfate sodium (DSS)-induced colitis was explored. The results showed that DOP treatment for 36 days reduced the symptoms of colitis caused by DSS, including reduction of the disease activity index and alleviation of colonic tissue damage. In addition, DOP downregulated the expression of key proteins of the TLR4/NF-κB signaling pathway and reduced the production of inflammatory cytokines. Furthermore, DOP could enhance the expression of tight junction proteins including ZO-1, Occludin, and Claudin-1 to restore intestinal mucosal barrier function. DOP also effectively regulates disordered intestinal flora and enhances the production of short-chain fatty acids, which is also beneficial in modulating gut internal environmental homeostasis, inhibiting inflammation, and restoring the intestinal barrier. These findings indicated that DOP can ameliorate DSS-induced chronic colitis by regulating gut microbiota, intestinal barrier, and inflammation, and it is a promising ingredient from D. officinale.

Virofree Associates with the Modulation of Gut Microbiomes and Alleviation of DSS-Induced IBD Symptoms in Mice

Inflammatory bowel disease (IBD) is a chronic, nonspecific inflammation of the intestines that primarily comprises Crohn's disease and ulcerative colitis. The incidence and prevalence of IBD have been increasing globally, highlighting the significance of research and prophylactic interventions. Virofree, a mixture of various botanical extracts (including grapes, cherries, olive leaves, marigolds, green tea, and others), has shown significant potential in disease prevention. This study examined the effects of Virofree on intestinal inflammation and the gut microbiota in mice using a dextran sulfate sodium (DSS)-induced model. The mice showed no adverse reactions when administered Virofree. Virofree administration reduced the disease activity index as indicated by amelioration of DSS-induced symptoms in the mice, including weight loss, diarrhea, and rectal bleeding. Regarding the gut microbiota, Virofree intervention modulated the DSS-induced decrease in gut microbial diversity; the Virofree group showed no increase in the phyla Proteobacteria or Verrucomicrobia while displaying an increase in the genus Duncaniella, bacteria that may have protective properties. These findings suggest that Virofree may have a direct or indirect impact on the composition of the gut microbiota and that it can alleviate the imbalance of the microbiome and intestinal inflammation caused by DSS treatment.

Dextran sulfate sodium-induced gut microbiota dysbiosis aggravates liver injury in mice with S100-induced autoimmune hepatitis

Recently, the incidence of autoimmune hepatitis (AIH) has gradually increased, and the disease can eventually develop into cirrhosis or even hepatoma if left untreated. AIH patients are often characterized by gut microbiota dysbiosis, but whether gut microbiota dysbiosis contributes to the progression of AIH remains unclear. In this study, we investigate the role of gut microbiota dysbiosis in the occurrence and development of AIH in mice with dextran sulfate sodium salt (DSS) induced colitis. C57BL/6J mice were randomly divided into normal group, S100-induced AIH group, and DSS+S100 group (1 % DSS in the drinking water), and the experimental cycle lasted for four weeks. We demonstrate that DSS administration aggravates hepatic inflammation and disruption of the intestinal barrier, and significantly changes the composition of gut microbiota in S100-induced AIH mice, which are mainly characterized by increased abundance of pathogenic bacteria and decreased abundance of beneficial bacteria. These results suggest that DSS administration aggravates liver injury of S100-induced AIH, which may be due to DSS induced gut microbiota dysbiosis, leading to disruption of the intestinal barrier, and then, the microbiota translocate to the liver, aggravating hepatic inflammation.

CDP-choline modulates cholinergic signaling and gut microbiota to alleviate DSS-induced inflammatory bowel disease

Inflammatory bowel diseases (IBD) represent chronic gastrointestinal inflammatory disorders characterized by a complex and underexplored pathogenic mechanism. Previous research has revealed that IBD patients often have a deficiency of choline and its metabolites, including acetylcholine (ACh) and phosphatidylcholine (PC), within the colon. However, a comprehensive study linking these three substances and their mechanistic implications in IBD remains lacking. This study aimed to investigate the efficacy and underlying mechanism of cytidine diphosphate (CDP)-choline (citicoline), an intermediate product of choline metabolism, in a mouse model of IBD induced by dextran sulfate sodium salt (DSS). The results demonstrated that CDP-choline effectively alleviated colonic inflammation and deficiencies in choline, ACh, and PC by increasing the raw material. Further detection showed that CDP-choline also increased the ACh content by altering the expression of high-affinity choline transporter (ChT1) and acetylcholinesterase (AChE) in DSS-induced mice colon. Moreover, CDP-choline increased the expression of alpha7 nicotinic acetylcholine receptor (α7 nAChR) and activated the cholinergic anti-inflammatory pathway (CAP), leading to reduced colon macrophage activation and proinflammatory M1 polarization in IBD mice, thus reducing the levels of TNF-α and IL-6. In addition, CDP-choline reduced intestinal ecological imbalance and increased the content of hexanoic acid in short-chain fatty acids (SCFAs) in mice. In conclusion, this study elucidates the ability of CDP-choline to mitigate DSS-induced colon inflammation by addressing choline and its metabolites deficiencies, activating the CAP, and regulating the composition of the intestinal microbiome and SCFAs content, providing a potential prophylactic and therapeutic approach for IBD.

Lactiplantibacillus plantarum ZJ316-fermented milk ameliorates dextran sulfate sodium-induced chronic colitis by improving the inflammatory response and regulating intestinal microbiota

The pathogenesis of inflammatory bowel disease may be related to local inflammatory damage and disturbances in intestinal microecology. Probiotic therapy is a safe and effective therapeutic approach. Considering that fermented milk is accepted and enjoyed by many people as a daily dietary intervention strategy, its potential to alleviate dextran sulfate sodium (DSS)-induced chronic colitis in mice needs to be explored. In this study, we evaluated the therapeutic effects of Lactiplantibacillus plantarum ZJ316-fermented milk by establishing a mouse model of DSS-induced chronic colitis. The results showed that the disease severity and colonic lesions of inflammatory bowel disease were effectively alleviated by ingestion of fermented milk. At the same time, the expression of proinflammatory cytokines (TNF-α, IL-1β, and IL-6) effectively decreased, and the expression of antiinflammatory cytokines (IL-10) increased. Results based on 16S rRNA gene sequencing indicated that the structure and diversity of intestinal microorganisms changed markedly by intake of L. plantarum ZJ316-fermented milk, and fermented milk reduced the abundance of harmful bacteria (Helicobacter) while promoting the growth of beneficial bacteria (Faecalibacterium, Lactiplantibacillus, and Bifidobacterium). Additionally, the levels of short-chain fatty acids (acetic acid, propionic acid, butyric acid, pentanoic acid, and isobutyric acid) were also increased. In conclusion, the intake of L. plantarum ZJ316-fermented milk can alleviate chronic colitis by suppressing the inflammatory response and regulating intestinal microbiota.

Lactoferrin deficiency during lactation increases the risk of depressive-like behavior in adult mice

BACKGROUND

Lactoferrin is an active protein in breast milk that plays an important role in the growth and development of infants and is implicated as a neuroprotective agent. The incidence of depression is currently increasing, and it is unclear whether the lack of lactoferrin during lactation affects the incidence of depressive-like behavior in adulthood.

RESULTS

Lack of lactoferrin feeding during lactation affected the barrier and innate immune functions of the intestine, disrupted the intestinal microflora, and led to neuroimmune dysfunction and neurodevelopmental delay in the hippocampus. When exposed to external stimulation, adult lactoferrin feeding-deficient mice presented with worse depression-like symptoms; the mechanisms involved were activation of the LPS-TLR4 signalling pathway in the intestine and hippocampus, reduced BDNF-CREB signaling pathway in hippocampus, increased abundance of depression-related bacteria, and decreased abundance of beneficial bacteria.

CONCLUSIONS

Overall, our findings reveal that lactoferrin feeding deficient during lactation can increase the risk of depressive-like behavior in adults. The mechanism is related to the regulatory effect of lactoferrin on the development of the "microbial-intestinal-brain" axis.

Dextran sulfate sodium-induced mild chronic colitis induced cognitive impairment accompanied by inhibition of neuronal maturation in adolescent mice

INTRODUCTION

Epidemiological studies indicated that inflammatory bowel disease (IBD), with Crohn's disease and ulcerative colitis as its two main types, is associated with dementia. However, little is known about how adolescents with IBD will affect their cognitive ability as adults. The hippocampus, which is crucial for memory and adult neurogenesis, is closely associated with modulation of cognitive processes. Using a low kDa dextran sulfate sodium (DSS, 5 kDa)-induced chronic colitis (mild chronic colitis) mice model in adolescent mice, we investigated the effects of mild chronic colitis on cognitive functions and hippocampal neurogenesis from adolescent mice to adult mice.

METHODS

We induced DSS-induced mild chronic colitis in C57BL/6J male mice by multiple-cycle administration of 1%-2% DSS in autoclaved drinking water. Mice were subjected to novel-object recognition and Y-maze tests. Neurogenesis markers and neuroinflammation-related proteins in the hippocampus of mice were measured. Tight junction proteins in the colon of mice were measured.

RESULTS

Mild chronic colitis induced cognitive impairment and decreased adult neurogenesis. Notably, we found a positive correlation with the protein levels between tight junction protein, ZO-1, in the colon and mature neuron marker, NeuN, in the hippocampus. Moreover, mild chronic colitis leads to hippocampal neuroinflammation in adolescent mice.

CONCLUSION

Our findings provide new evidence of the association between IBD and dementia risk.

Correlation between gut microbiota and the development of Graves' disease: A prospective study

The association between gut microbiota and development of Graves' disease (GD) remains unclear. This study aimed to profile the gut microbiota of 65 patients newly diagnosed with GD before and after treatment and 33 physical examination personnel via 16S rRNA sequencing. Significant differences in the gut microbiota composition were observed between the two groups, showing relative bacterial abundances of 1 class, 1 order, 5 families, and 14 genera. After treatment, the abundance of the significantly enriched biota in the GD group decreased considerably, whereas that of the previously decreased biota increased considerably. Further, interleukin-17 levels decreased significantly. The random forest method was used to identify 12 genera that can distinguish patients with GD from healthy controls. Our study revealed that the gut microbiota of patients with GD exhibit unique characteristics compared with that of healthy individuals, which may be related to an imbalance in the immune system and gut microbiota.

iTRAQ-based proteomic analysis of imiquimod in the treatment of ulcerative colitis

OBJECTIVE

In this study, we explored the potential mechanisms and the signaling pathways involved in the treatment of Ulcerative Colitis (UC) with imiquimod (IMQ).

METHODS

The UC mouse model was established by treating C57BL/6J mice with 3% Dextran Sulfate Sodium (DSS). Then, the UC-related symptoms were examined. Disease Activity Index (DAI) was estimated based on weight loss, stool consistency, and occult bleeding or hematochezia. Histological changes were evaluated by Hematoxylin and Eosin (H&E) staining. Furthermore, we used multiplexed Isobaric Tagging for Relative and Absolute Protein Quantification (iTRAQ) technique coupled with high-throughput liquid chromatography tandem mass spectrometry (LC-MS/MS) to determine the differentially expressed proteins (DEPs).

RESULTS

Administration of 3% DSS for 7 days induced acute colitis associated with diarrhea, hematochezia, weight loss, and colon shortening. However, after IMQ administration, almost all the above symptoms were improved by different degrees. Specifically, the DAI, histological disorder, and colon shortening were attenuated. In iTRAQ analysis, a total of 4170 proteins were identified with a high confidence (≥ 95% confidence). The numbers of DEPs between the normal and UC model mice, between the normal and the IMQ-treated therapy mice, as well as between the model and the therapy mice were 317, 253, and 209, respectively. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses revealed that the DEPs involved in the complement and coagulation cascades were downregulated in IMQ-treated therapy group.

CONCLUSIONS

IMQ might ameliorate colitis by suppressing the complement and coagulation cascades pathway, which might serve as new therapeutic strategies for the treatment of patients with UC.

Mitigating Effects of Tenebrio molitor Larvae Powder Administration in Mice with Dextran Sodium Sulfate (DSS)- Induced Colitis

BACKGROUND

Ulcerative colitis (UC) is an inflammatory bowel disease that affects people worldwide. The causes of UC are diverse, and symptoms include diarrhea, weight loss, anemia, rectal bleeding, and bloody stools. Tenebrio molitor larvae have recently gained attention as edible insects with various physiological and medical effects. Research on the anti-inflammatory effects of ingesting Tenebrio molitor larvae powder (TMLP) is being actively conducted. In this study, TMLP was administered to mice with dextran sodium sulfate (DSS)-induced colitis to investigate its effects in reducing colitis symptoms.

METHODS

Mice were initially given 3% DSS in water to induce colitis and then feed containing 0%, 2%, or 4% TMLP. Pathologic changes in colon tissues were assessed by histology, and neutrophil levels were measured by myeloperoxidase (MPO) assay. Levels of IL-1β, IL-6, and TNF-α were measured using real-time PCR and ELISA assays, and IκB and NF-kB protein levels were measured by western blotting.

RESULT

Disease Activity Index (DAI) scores and MPO activity were reduced in TMLP-treated mice, and colon length increased as much as normal mice. Pathologic changes in the colon tissues of DSS-induced mice were attenuated, and the expression of inflammatory cytokine genes IL-1β, IL-6, and TNF-α decreased. Concomitant decreases in the protein expression of IL-1β and IL-6 were confirmed using ELISA. Western blotting revealed that levels of phosphorylated forms of IκB and NF-κB also decreased.

CONCLUSION

These results show that feeding TMLP to DSS-induced mice inhibited the typical inflammatory pathway of colitis. Therefore, TMLP shows potential as a food additive that can help treat colitis.
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Lactobacillus rhamnosus GG ameliorates noise-induced cognitive deficits and systemic inflammation in rats by modulating the gut-brain axis

Background

Environmental noise exposure is linked to neuroinflammation and imbalance of the gut microbiota. Promoting gut microbiota homeostasis may be a key factor in relieving the deleterious non-auditory effects of noise. This study aimed to investigate the effect of Lactobacillus rhamnosus GG (LGG) intervention on noise-induced cognitive deficits and systemic inflammation in rats.

Methods

Learning and memory were assessed using the Morris water maze, while 16S rRNA sequencing and gas chromatography-mass spectrometry were used to analyze the gut microbiota and short-chain fatty acid (SCFA) content. Endothelial tight junction proteins and serum inflammatory mediators were assessed to explore the underlying pathological mechanisms.

Results

The results indicated that Lactobacillus rhamnosus GG intervention ameliorated noise-induced memory deterioration, promoted the proliferation of beneficial bacteria, inhibited the growth of harmful bacteria, improved dysregulation of SCFA-producing bacteria, and regulated SCFA levels. Mechanistically, noise exposure led to a decrease in tight junction proteins in the gut and hippocampus and an increase in serum inflammatory mediators, which were significantly alleviated by Lactobacillus rhamnosus GG intervention.

Conclusion

Taken together, Lactobacillus rhamnosus GG intervention reduced gut bacterial translocation, restored gut and blood-brain barrier functions, and improved gut bacterial balance in rats exposed to chronic noise, thereby protecting against cognitive deficits and systemic inflammation by modulating the gut-brain axis.

Ginkgo biloba Extract Preventively Intervenes in Citrobacter Rodentium-Induced Colitis in Mice

Inflammatory bowel disease (IBD) represents a highly recurrent gastrointestinal disorder and global public health issue. However, it lacks effective and safe strategies for its control. Although Ginkgo biloba extract (GBE) has been suggested to exhibit preventive and therapeutic activity for the control of IBD, whether its activity is associated with its ability to modulate intestinal microbiota remains to be addressed. To investigate the effect of GBE on controlling IBD, a Citrobacter Rodentium (CR)-induced mouse colitis model was used, and then histopathological examinations, biochemical assays, immunohistochemistry, and immunoblotting were performed to detect histological changes, cytokines, and tight junction (TJ) proteins in the intestine samples. We also studied 16s rRNA to detect changes in intestinal microbiota and used GC-MS to determine the microbiota-related metabolites short chain fatty acids (SCFAs). The results of our studies revealed that pre-treatment with GBE was sufficient for protecting the animals from CR-induced colitis. As a mechanism for GBE activity, GBE treatment was able to modulate the intestinal microbiota and increase the SCFAs capable of decreasing the pro-inflammatory factors and up-regulating the anti-inflammatory factors while elevating the intestinal-barrier-associated proteins to maintain the integrity of the intestines. Accordingly, our results led to a strong suggestion that GBE should be seriously considered in the preventive control of CR-induced colitis and in the development of effective and safe therapeutic strategies for controlling IBD.

Behavioral abnormalities in C57BL/6 mice with chronic ulcerative colitis induced by DSS

BACKGROUND

Clinical epidemiological studies have found that some patients with ulcerative colitis (UC) are prone to mental disorders. DSS-induced acute and chronic UC models are often used to evaluate the efficacy of anti-UC drugs. However, whether DSS has an effect on mouse behavior has not been reported.

METHODS

Acute and chronic UC models were induced by 3% DSS and 1.5% DSS, respectively. The bloody stool, the changes in the colon length, and histopathological changes in the colon were used to evaluate the success of the animal model. The behavior of mice was evaluated by open field experiment, tail suspension experiment and Sucrose preference test.

RESULTS

The weight of mice in 3% DSS group decreased significantly, the DAI score increased significantly, the colon length of mice was significantly shortened, and the structure of colonic crypts was abnormal, which showed inflammatory cell infiltration and shrinkage of crypts. Compared with the control group, the immobility time of 3%DSS group mice in the tail suspension test and forced swimming test had no effect, the number of running and grooming times was significantly reduced, and there was no significant difference in the number of standing times. No abnormality was observed in HE staining of the hippocampus. However, in 1.5% DSS-induced chronic UC model, behavioral and hippocampal abnormalities were observed not only UC symptoms.

CONCLUSIONS

The acute UC model induced by 3% DSS has certain influence on the behavior of mice, but the mental state of mice is normal, which may be the abnormal behavior caused by UC symptoms; However, the chronic UC model induced by 1.5% DSS has a significant effect on the behavior of mice, and the mice have mental disorders, which are caused by mental disorders.

Prediction model of colorectal cancer (CRC) lymph node metastasis based on intestinal bacteria

BACKGROUND

Lymph node metastasis is the main metastatic mode of CRC. Lymph node metastasis affects patient prognosis.

OBJECTIVE

To screen differential intestinal bacteria for CRC lymph node metastasis and construct a prediction model.

METHODS

First, fecal samples of 119 CRC patients with lymph node metastasis and 110 CRC patients without lymph node metastasis were included for the detection of intestinal bacterial 16S rRNA. Then, bioinformatics analysis of the sequencing data was performed. Community structure and composition analysis, difference analysis, and intragroup and intergroup correlation analysis were conducted between the two groups. Finally, six machine learning models were used to construct a prediction model for CRC lymph node metastasis.

RESULTS

The community richness and the community diversity at the genus level of the two groups were basically consistent. A total of 12 differential bacteria (Agathobacter, Catenibacterium, norank_f__Oscillospiraceae, Lachnospiraceae_FCS020_group, Lachnospiraceae_UCG-004, etc.) were screened at the genus level. Differential bacteria, such as Agathobacter, Catenibacterium, norank_f__Oscillospiraceae, and Lachnospiraceae_FCS020_group, were more associated with no lymph node metastasis in CRC. In the discovery set, the RF model had the highest prediction accuracy (AUC = 1.00, 98.89% correct, specificity = 55.21%, sensitivity = 55.95%). In the test set, SVM model had the highest prediction accuracy (AUC = 0.73, 72.92% correct, specificity = 69.23%, sensitivity = 88.89%). Lachnospiraceae_FCS020_group was the most important variable in the RF model. Lachnospiraceae_UCG - 004 was the most important variable in the SVM model.

CONCLUSION

CRC lymph node metastasis is closely related to intestinal bacteria. The prediction model based on intestinal bacteria can provide a new evaluation method for CRC lymph node metastasis.

ROS-triggered self-disintegrating and pH-responsive astaxanthin nanoparticles for regulating the intestinal barrier and colitis

Smart delivery systems with stimuli-responsive capability are able to improve the bioaccessibility through increasing the solubility, physicochemical stability and biocompatibility of bioactive compounds. In this study, the astaxanthin nanoparticles with reactive oxygen species (ROS) and pH dual-response function were design and constructed using poly (propylene sulfide) covalently modified sodium alginate as carriers based on ultrasonic assisted self-assembly strategy. Atomic force microscope and scanning electron microscope analysis showed that the nanoparticles were spherical in shape with a size of around 260 nm. Meanwhile, the astaxanthin nanoparticles showed both pH and ROS stimuli-responsive release characteristics. In vitro cell experiments showed that astaxanthin nanoparticles significantly inhibited the production of ROS and mitochondrial depolarization induced by oxidative stress. In vivo colitis experiment of mice revealed that astaxanthin nanoparticles could significantly relieve colitis, protect the integrity of colon tissue and restore the expression of tight junction proteins ZO-1 and occludin. The abundance of Lactobacillus and Lachnospiraceae, and the ratio of Firmicutes/Bacteroidota of gut microbiota were significantly improved after intervention of the stimuli-responsive astaxanthin nanoparticles. This work provided a simple strategy for constructing ROS/pH dual response delivery system, which provided an experimental basis for improving the oral bioavailability of hydrophobic active compounds.

A soil-inspired dynamically responsive chemical system for microbial modulation

Interactions between the microbiota and their colonized environments mediate critical pathways from biogeochemical cycles to homeostasis in human health. Here we report a soil-inspired chemical system that consists of nanostructured minerals, starch granules and liquid metals. Fabricated via a bottom-up synthesis, the soil-inspired chemical system can enable chemical redistribution and modulation of microbial communities. We characterize the composite, confirming its structural similarity to the soil, with three-dimensional X-ray fluorescence and ptychographic tomography and electron microscopy imaging. We also demonstrate that post-synthetic modifications formed by laser irradiation led to chemical heterogeneities from the atomic to the macroscopic level. The soil-inspired material possesses chemical, optical and mechanical responsiveness to yield write-erase functions in electrical performance. The composite can also enhance microbial culture/biofilm growth and biofuel production in vitro. Finally, we show that the soil-inspired system enriches gut bacteria diversity, rectifies tetracycline-induced gut microbiome dysbiosis and ameliorates dextran sulfate sodium-induced rodent colitis symptoms within in vivo rodent models.

Dark-purple rice extract modulates gut microbiota composition in acetic acid– and indomethacin-induced inflammatory bowel disease in rats

Ulcerative colitis (UC) and Crohn's disease (CD) are two major forms of inflammatory bowel disease (IBD). The disease has been linked with gut microbiota dysbiosis in which the balance of commensal communities is disrupted. Accumulating evidence demonstrates that treatment with biologically active compounds can modulate gut microbiota composition in animal models. Our previous work has also shown the beneficial effect of Luem Pua (LP) rice extract, which is rich in anthocyanins, on inflammation. However, its effect on gut microbiota is yet to be explored. In this study, we profiled fecal microbiota of acetic acid (AA)-induced UC and indomethacin (ID)-induced CD rat models with and without pretreatment with LP rice extract by 16S rRNA gene sequencing. The results showed that gut microbiota communities of rats were altered by both AA-induced UC and ID-induced CD. The relative abundances of beneficial bacteria, especially the Lachnospiraceae NK4A136 group and Lactobacillus, were decreased in the AA-induced UC model, while some opportunistic pathogens (Bacteroides, Escherichia/Shigella, Fusobacterium, and Veillonella) were raised by ID-induced CD. Interestingly, pretreatment with LP rice extract before AA-inducing UC in rats increased the proportion of the butyrate-producing bacteria (Lachnospiraceae NK4A136 group). The abundances of these beneficial bacteria and other SCFA-producing bacteria were unaffected by the indomethacin treatment with LP. Overall, our study revealed different impacts of AA-induced UC and ID-induced CD on changes in community composition and hinted at how LP may protect against UC by modifying the gut microbiota.

Oral gamma-cyclodextrin-encapsulated tributyrin supplementation in young pigs with experimentally induced colitis

Disruption of intestinal integrity and barrier function due to tissue inflammation has negative implications on overall growth and well-being in young pigs. In this study, we investigated the effects of oral gamma-cyclodextrin-encapsulated tributyrin (TBCD) in young pigs experiencing dextran sodium sulfate (DSS)-induced colitis. Pigs (n = 32 boars) were weaned from the sow at postnatal day (PND) 2, allotted to treatment based on the litter of origin and body weight (BW), and reared artificially over a 26-d feeding period. Treatment groups included: 1) nutritionally adequate (control) milk replacer, no DSS (Control n = 8), 2) control milk replacer plus oral DSS (DSS, n = 7), and 3) control diet supplemented with 8.3 g of TBCD per kg of reconstituted milk replacer plus oral DSS (TBCD + DSS, n = 8). Colitis was induced by administering DSS at 1.25 g of DSS/kg BW daily in a reconstituted milk replacer from PND 14-18. Milk replacer and water were provided ad libitum throughout the 26-d study. All the data were analyzed using a one-way ANOVA using the MIXED procedure of SAS. Control and DSS pigs had similar BW throughout the study, while TBCD + DSS pigs exhibited decreased (P < 0.05) BW starting at approximately PND 15. Additionally, average daily gain (ADG) before and after initiation of DSS dosing, along with over the total study duration, was decreased (P < 0.05) in pigs receiving TBCD + DSS compared with the Control. Milk disappearance was decreased (P < 0.05) in TBCD + DSS pigs when compared with Control and DSS groups. Both the concentration and molar ratio of cecal butyrate concentrations were increased (P < 0.05) in TBCD + DSS pigs compared with the Control group. The DSS and TBCD + DSS treatments also increased (P < 0.05) butyrate concentrations in the luminal contents with the proximal colon compared with Control. TBCD + DSS and DSS pigs had increased (P < 0.05) mucosal width in the distal colon compared with Control, thereby indicating heightened intestinal inflammation. Overall, oral supplementation of encapsulated tributyrin increased the concentration of butyrate in the colon, but was unable to mitigate the negative effects of DSS-induced colitis.

Gut Inflammation Induced by Finasteride Withdrawal: Therapeutic Effect of Allopregnanolone in Adult Male Rats

The treatment with finasteride (i.e., an inhibitor of 5α-reductase) may be associated with different side effects (i.e., depression, anxiety, cognitive impairment and sexual dysfunction) inducing the so-called post finasteride syndrome (PFS). Moreover, previous observations in PFS patients and an experimental model showed alterations in gut microbiota populations, suggesting an inflammatory environment. To confirm this hypothesis, we have explored the effect of chronic treatment with finasteride (i.e., for 20 days) and its withdrawal (i.e., for 1 month) on the levels of steroids, neurotransmitters, pro-inflammatory cytokines and gut permeability markers in the colon of adult male rat. The obtained data demonstrate that the levels of allopregnanolone (ALLO) decreased after finasteride treatment and after its withdrawal. Following the drug suspension, the decrease in ALLO levels correlates with an increase in IL-1β and TNF-α, serotonin and a decrease in dopamine. Importantly, ALLO treatment is able to counteract some of these alterations. The relation between ALLO and GABA-A receptors and/or pregnenolone (ALLO precursor) could be crucial in their mode of action. These observations provide an important background to explore further the protective effect of ALLO in the PFS experimental model and the possibility of its translation into clinical therapy.

Regulation of a High-Iron Diet on Lipid Metabolism and Gut Microbiota in Mice

Iron homeostasis disorder is associated with the imbalance of lipid metabolism, while the specific interaction remains unclear. In the present study, we investigated the effect of a high-iron diet on lipid metabolism in mice. The C57BL/6 mice were fed with a normal diet (WT) or a high-iron diet (WT + Fe) for 12 weeks. We found that mice in the WT + Fe group showed a significant decrease in body weight gain, body fat and lipid accumulation of liver when compared with mice in the WT group. Accordingly, serum total cholesterol and triglyceride levels were both reduced in mice with a high-iron diet. Moreover, mice in the WT + Fe group exhibited a significant decrease in expression of genes regulating adipogenesis and adipocyte differentiation, and a significant increase in expression of fat hydrolysis enzyme genes in both liver and adipose tissues, which was consistent with their dramatic reduction in adipocyte cell size. In addition, a high-iron diet decreased the relative abundance of beneficial bacteria (Akkermansia, Bifidobacterium and Lactobacillus) and increased the relative abundance of pathogenic bacteria (Romboutsia and Erysipelatoclostridium). Thus, our research revealed that a high-iron diet reduced lipid deposition by inhibiting adipogenesis and promoting lipolysis. Altered gut microbial composition induced by a high-iron diet may not play a critical role in regulating lipid metabolism, but might cause unwanted side effects such as intestinal inflammation and damaged villi morphology at the intestinal host–microbe interface. These findings provide new insights into the relationship among iron, lipid metabolism and gut microbiota.

Alginate Oligosaccharides Ameliorate DSS-Induced Colitis through Modulation of AMPK/NF-κB Pathway and Intestinal Microbiota

Alginate oligosaccharides (AOS) are shown to have various biological activities of great value to medicine, food, and agriculture. However, little information is available about their beneficial effects and mechanisms on ulcerative colitis. In this study, AOS with a polymerization degree between 2 and 4 were found to possess anti-inflammatory effects in vitro and in vivo. AOS could decrease the levels of nitric oxide (NO), IL-1β, IL-6, and TNFα, and upregulate the levels of IL-10 in both RAW 264.7 and bone-marrow-derived macrophage (BMDM) cells under lipopolysaccharide (LPS) stimulation. Additionally, oral AOS administration could significantly prevent bodyweight loss, colonic shortening, and rectal bleeding in dextran sodium sulfate (DSS)-induced colitis mice. AOS pretreatment could also reduce disease activity index scores and histopathologic scores and downregulate proinflammatory cytokine levels. Importantly, AOS administration could reverse DSS-induced AMPK deactivation and NF-κB activation in colonic tissues, as evidenced by enhanced AMPK phosphorylation and p65 phosphorylation inhibition. AOS could also upregulate AMPK phosphorylation and inhibit NF-κB activation in vitro. Moreover, 16S rRNA gene sequencing of gut microbiota indicated that supplemental doses of AOS could affect overall gut microbiota structure to a varying extent and specifically change the abundance of some bacteria. Medium-dose AOS could be superior to low- or high-dose AOS in maintaining remission in DSS-induced colitis mice. In conclusion, AOS can play a protective role in colitis through modulation of gut microbiota and the AMPK/NF-kB pathway.

Dietary Oyster (Crassostrea gigas) Extract Ameliorates Dextran Sulfate Sodium-Induced Chronic Experimental Colitis by Improving the Composition of Gut Microbiota in Mice

Previously, we have reported that the intake of oyster extract (OE), prepared from Pacific oysters (Crassostrea gigas), can attenuate symptoms of dextran sulfate sodium (DSS)-induced acute experimental colitis in mice. Herein, we aimed to evaluate whether OE intake ameliorates chronic experimental colitis induced by repeated DSS administration in mice. Male C57BL/6J (4-week-old) mice were fed either the standard diet AIN93G (control diet) or the control diet containing 5.0% (w/w) OE (OE diet). After 21 days of diet feeding, chronic experimental colitis was induced by three cycles of 2.0% (w/w) DSS solution administration (5 days), followed by distilled water (5 days). Mice fed OE alleviated the shortened colonic length, increased the relative weight of the spleen, colonic histopathological score (regeneration), and blood in the stool score compared with mice fed control diet. A tendency to improve the α-diversity of fecal microbiota, which was exacerbated by colitis, was observed in mice fed OE. Correlation analysis suggested that the anti-colitis effect of OE intake could be related to the valeric acid content and relative abundances of Ruminococcus and Enterococcus in the feces. In conclusion, OE could ameliorate DSS-induced chronic experimental colitis by improving the gut environment, including the microbiota community and SCFA composition.

Mitochondrial complex I dysfunction alters the balance of soluble and membrane-bound TNF during chronic experimental colitis

Inflammatory bowel disease (IBD) is a complex, chronic, relapsing and heterogeneous disease induced by environmental, genomic, microbial and immunological factors. MCJ is a mitochondrial protein that regulates the metabolic status of macrophages and their response to translocated bacteria. Previously, an acute murine model of DSS-induced colitis showed increased disease severity due to MCJ deficiency. Unexpectedly, we now show that MCJ-deficient mice have augmented tumor necrosis factor α converting enzyme (TACE) activity in the context of chronic inflammation. This adaptative change likely affects the balance between soluble and transmembrane TNF and supports the association of the soluble form and a milder phenotype. Interestingly, the general shifts in microbial composition previously observed during acute inflammation were absent in the chronic model of inflammation in MCJ-deficient mice. However, the lack of the mitochondrial protein resulted in increased alpha diversity and the reduction in critical microbial members associated with inflammation, such as Ruminococcus gnavus, which could be associated with TACE activity. These results provide evidence of the dynamic metabolic adaptation of the colon tissue to chronic inflammatory changes mediated by the control of mitochondrial function.