An insight into the gut microbiota after Schistosoma japonicum eggs immunization in an experimental ulcerative colitis model.

Schistosome infection and schistosome-derived products have been implicated in the prevention and alleviation of inflammatory bowel disease by manipulating the host immune response, whereas the role of gut microbiota in this protective effect remains poorly understood. In this study, we found that the intraperitoneal immunization with Schistosoma japonicum eggs prior to dextran sulfate sodium (DSS) application significantly ameliorated the symptoms of DSS-induced acute colitis, which was characterized by higher body weight, lower disease activity index score and macroscopic inflammatory scores. We demonstrated that the immunomodulatory effects of S. japonicum eggs were accompanied by an influence on gut microbiota composition, abundance, and diversity, which increased the abundance of genus Turicibacter, family Erysipelotrichaceae, phylum Firmicutes, and decreased the abundance of genus Odoribacter, family Marinifilaceae, order Bacteroidales, class Bacteroidia, phylum Bacteroidota. In addition, Lactobacillus was identified as a biomarker that distinguishes healthy control mice from DSS-induced colitis mice. The present study revealed the importance of the gut microbiota in S. japonicum eggs exerting protective effects in an experimental ulcerative colitis (UC) model, providing an alternative strategy for the discovery of UC prevention and treatment drugs.

Integrative analysis of single-cell RNA-seq and gut microbiome metabarcoding data elucidates macrophage dysfunction in mice with DSS-induced ulcerative colitis.

Ulcerative colitis (UC) is a significant inflammatory bowel disease caused by an abnormal immune response to gut microbes. However, there are still gaps in our understanding of how immune and metabolic changes specifically contribute to this disease. Our research aims to address this gap by examining mouse colons after inducing ulcerative colitis-like symptoms. Employing single-cell RNA-seq and 16 s rRNA amplicon sequencing to analyze distinct cell clusters and microbiomes in the mouse colon at different time points after induction with dextran sodium sulfate. We observe a significant reduction in epithelial populations during acute colitis, indicating tissue damage, with a partial recovery observed in chronic inflammation. Analyses of cell-cell interactions demonstrate shifts in networking patterns among different cell types during disease progression. Notably, macrophage phenotypes exhibit diversity, with a pronounced polarization towards the pro-inflammatory M1 phenotype in chronic conditions, suggesting the role of macrophage heterogeneity in disease severity. Increased expression of Nampt and NOX2 complex subunits in chronic UC macrophages contributes to the inflammatory processes. The chronic UC microbiome exhibits reduced taxonomic diversity compared to healthy conditions and acute UC. The study also highlights the role of T cell differentiation in the context of dysbiosis and its implications in colitis progression, emphasizing the need for targeted interventions to modulate the inflammatory response and immune balance in colitis.

Biochanin A mitigates ulcerative colitis and intestinal inflammation in mice by inhibiting MAPK/NF-kB (p65) axis.

Ulcerative colitis (UC) is a chronic problem of the intestine and relapsing in nature. Biochanin A is a nature-derived isoflavonoid and has numerous bioactivities. However, its role against UC and intestinal inflammation remains obscure. We aimed to comprehensively explore the pharmacological effect of biochanin A in alleviating colitis and to evaluate the potential mechanisms. Initially, we explored the anti-inflammatory action of biochanin A (15, 30, and 60 µM) by employing lipopolysaccharide (LPS)-activated RAW 264.7 cells. In RAW 264.7 cells under LPS stimulation, biochanin A inhibited the elevation of reactive oxygen species (ROS) (p < 0.0001), interleukin (IL)-1ß (p < 0.0001), IL-18 (p < 0.01), and tumor necrosis factor (TNF)-α (p < 0.01) release, nitrite production (p < 0.0001), and the expression of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) proteins. Next, we studied the effectiveness of biochanin A (20 and 40 mg/kg) in mouse colitis induced with dextran sulfate sodium (DSS) by assessing colon length, disease activity index (DAI) scoring, and performing colonoscopy and histological analysis. The pro-inflammatory cytokines were estimated using ELISA. Western blot studies were performed to assess underlying mechanisms. In mice, biochanin A treatment alleviated DAI score (p < 0.0001), restored colon length (p < 0.05) and morphology, and re-established colon histopathology. Biochanin A affects the phosphorylation of proteins associated with NF-κB (p65) and mitogen-activated protein kinase (MAPK) axis and regulates colonic inflammation by reducing the expression of inflammatory cytokines and myeloperoxidase (MPO) activity. Altogether, our findings support the idea that the anticolitis potential of biochanin A is allied with anti-inflammatory activity by inhibiting the MAPK/NF-κB (p65) axis. Hence, biochanin A may be an alternative option to alleviate the risk of colitis.

Anxiolytic effects of Enterococcus faecalis 2001 on a mouse model of colitis.

Ulcerative colitis (UC) is a refractory inflammatory bowel disease, which is known to cause psychiatric disorders such as anxiety and depression at a high rate in addition to peripheral inflammatory symptoms. However, the pathogenesis of these psychiatric disorders remains mostly unknown. While prior research revealed that the Enterococcus faecalis 2001 (EF-2001) suppressed UC-like symptoms and accompanying depressive-like behaviors, observed in a UC model using dextran sulfate sodium (DSS), whether it has an anxiolytic effect remains unclear. Therefore, we examined whether EF-2001 attenuates DSS-induced anxiety-like behaviors. Treatment with 2% DSS for seven days induced UC-like symptoms and anxiety-like behavior through the hole-board test, increased serum lipopolysaccharide (LPS) and corticosterone concentration, and p-glucocorticoid receptor (GR) in the prefrontal cortex (PFC), and decreased N-methyl-D-aspartate receptor subunit (NR) 2A and NR2B expression levels in the PFC. Interestingly, these changes were reversed by EF-2001 administration. Further, EF-2001 administration enhanced CAMKII/CREB/BDNF-Drebrin pathways in the PFC of DSS-treated mice, and labeling of p-GR, p-CAMKII, and p-CREB showed colocalization with neurons. EF-2001 attenuated anxiety-like behavior by reducing serum LPS and corticosterone levels linked to the improvement of UC symptoms and by facilitating the CAMKII/CREB/BDNF-Drebrin pathways in the PFC. Our findings suggest a close relationship between UC and anxiety.

Experimental colitis in young Tg2576 mice accelerates the onset of an Alzheimer's-like clinical phenotype.

Systemic inflammation and neuroinflammation affect the natural course of the sporadic form of Alzheimer's disease (AD), as supported by epidemiological and preclinical data, and several epidemiological studies indicate a higher prevalence of AD in patients with inflammatory bowel disease. In this study, we explored whether colitis induced by dextran sulfate sodium (DSS) in young, presymptomatic/preplaque mice worsens and/or anticipates age-dependent cognitive impairment in Tg2576, a widely used mouse model of AD. We demonstrated that DSS colitis induced in young Tg2576 mice anticipates the onset age of learning and memory deficit in the Morris water maze test. To explore potential mechanisms behind the acceleration of cognitive decline in Tg2576 mice by DSS colitis, we focused on gut microbiota, systemic inflammation and neuroinflammation markers. We observed a Firmicutes/Bacteroidetes ratio change in Tg2576 DSS animals comparable to that of elderly Tg2576 mice, suggesting accelerated microbiota aging in Tg2576 DSS mice, a change not observed in C57BL6 DSS mice. We also observed substantial differences between Tg2576 and WT mice in several inflammation and neuroinflammation-related parameters as early as 3 months of age, well before plaque deposition, a picture which evolved rapidly (between 3 and 5.5 months of age) in contrast to Tg2576 and WT littermates not treated with DSS. In detail, following induction of DSS colitis, WT and Tg2576 mice exhibited contrasting features in the expression level of inflammation-evoked astrocyte-associated genes in the hippocampus. No changes in microglial features occurred in the hippocampus between the experimental groups, whereas a reduced glial fibrillary acidic protein immunoreactivity was observed in Tg2576 vs. WT mice. This finding may reflect an atrophic, "loss-of-function" profile, further exacerbated by DSS where a decreased of GFAP mRNA expression level was detected. In conclusion, we suggest that as-yet unidentified peripheral mediators evoked by DSS colitis and involving the gut-brain axis emphasize an astrocyte "loss-of-function" profile present in young Tg2576 mice, leading to impaired synaptic morphological and functional integrity as a very early sign of AD.

Tectorigenin inhibits inflammatory responses in murine inflammatory bowel disease and LPS-stimulated macrophages via inactivating MAPK signaling pathway.

BACKGROUND: Considering the antihepatitis effects of Tectorigenin (TEC), and the same adenosine mitogen-activated protein kinase (MAPK) pathway in both hepatitis and inflammatory bowel disease (IBD) models, exploring the role of TEC in IBD is contributive to develop a new treatment strategy against IBD. METHODS: The IBD mouse model was constructed by feeding with dextran sodium sulfate (DSS) and injection of TEC. Afterward, the mouse body weight, colon length, and disease activity index (DAI) were tested to assess the enteritis level. Mouse intestine lesions were detected by hematoxylin and eosin staining. Murine macrophages underwent lipopolysaccharide (LPS) induction to establish an inflammation model. Cell viability was determined by cell counting kit-8 assay. Enzyme-linked immunosorbent assay was performed to measure interleukin 6 (IL-6) and tumor necrosis factor-α (TNF-α) levels. Cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) expressions were quantified via quantitative reverse transcription polymerase chain reaction. Levels of MAPK pathway-related proteins (p-P38, P38, p-Jun N-terminal kinase (JNK), JNK, signal-regulated kinase (ERK), p-ERK), COX-2 and iNOS were quantitated by Western blot. RESULTS: TEC improved the inflammatory response through ameliorating weight loss, shortening colon, and increasing DAI score in IBD mouse. Expressions of intestinal inflammatory factors (IL-6, TNF-α, iNOS and COX-2) and MAPK pathway-related proteins (p-P38, p-JNK, and p-ERK) were increased both in DSS-induced mouse intestinal tissue, but TEC inhibited expressions of inflammatory factors. The same increased trend was identified in LPS-induced macrophages, but TEC improved macrophage inflammation, as evidenced by downregulation of inflammatory factors. CONCLUSION: TEC mitigates IBD and LPS-induced macrophage inflammation in mice via inhibiting MAPK signaling pathway.

Oxidative Stress-Responsive Apoptosis Inducing Protein (ORAIP) Plays a Critical Role in Dextran Sulfate Sodium-Induced Murine Model of Ulcerative Colitis.

Oxidative stress is implicated in the pathogenesis of various acute disorders including ischemia/reperfusion injury, ultraviolet/radiation burn, as well as chronic disorders such as dyslipidemia, atherosclerosis, diabetes mellitus, chronic renal disease, and inflammatory bowel disease (IBD). However, the precise mechanism involved remains to be clarified. We formerly identified a novel apoptosis-inducing humoral protein, in a hypoxia/reoxygenation-conditioned medium of cardiac myocytes, which proved to be 69th tyrosine-sulfated eukaryotic translation initiation factor 5A (eIF5A). We named this novel tyrosine-sulfated secreted form of eIF5A Oxidative Stress-Responsive Apoptosis-Inducing Protein (ORAIP). To investigate the role of ORAIP in a dextran sulfate sodium (DSS)-induced murine model of ulcerative colitis (UC), we analyzed the effects of in vivo treatment with anti-ORAIP neutralizing monoclonal antibody (mAb) on the DSS-induced disease exacerbation. The body weight in anti-ORAIP mAb-treated group was significantly heavier than that in a mouse IgG-treated control group on day 8 of DSS-treatment ((85.21 ± 1.03%) vs. (77.38 ± 2.07%); (mean ± SE0, n = 5 each, p < 0.01, t-test). In vivo anti-ORAIP mAb-treatment also significantly suppressed the shortening of colon length as well as Disease Activity Index (DAI) score ((5.00 ± 0.44) vs. (8.20 ± 0.37); (mean ± SE), n = 5 each, p < 0.001, t-test) by suppressing inflammation of the rectal tissue and apoptosis of intestinal mucosal cells. These data reveal the pivotal role of ORAIP in DSS-induced oxidative stress involved in an animal model of UC.

Nitazoxanide protects against experimental ulcerative colitis through improving intestinal barrier and inhibiting inflammation.

Ulcerative colitis is a chronic disease with colonic mucosa injury. Nitazoxanide is an antiprotozoal drug in clinic. Nitazoxanide and its metabolite tizoxanide have been demonstrated to activate AMPK and inhibit inflammation, therefore, the aim of the present study is to investigate the effect of nitazoxanide on dextran sulfate sodium (DSS)-induced colitis and the underlying mechanism. Oral administration of nitazoxanide ameliorated the symptoms of mice with DSS-induced colitis, as evidenced by improving the increased disease activity index (DAI), the decreased body weight, and the shortened colon length. Oral administration of nitazoxanide ameliorated DSS-induced intestinal barrier dysfunction and reduced IL-6 and IL-17 expression in colon tissues. Mechanistically, nitazoxanide and its metabolite tizoxanide treatment activated AMPK and inhibited JAK2/STAT3 signals. Nitazoxanide and tizoxanide treatment increased caudal type homeobox 2 (CDX2) expression, increased alkaline phosphatase (ALP) activity and promoted tight junctions in Caco-2 cells. Nitazoxanide and tizoxanide treatment restored the decreased zonula occludens-1(ZO-1) and occludin protein levels induced by LPS or IL-6 in Caco-2 cells. On the other hand, nitazoxanide and tizoxanide regulated macrophage bias toward M2 polarization, as evidenced by the increased arginase-1expression in bone marrow-derived macrophages (BMDM). Nitazoxanide and tizoxanide reduced the increased IL-6, iNOS and CCL2 pro-inflammatory gene expressions and inhibited JAK2/STAT3 activation in BMDM induced by LPS. In conclusion, nitazoxanide protects against DSS-induced ulcerative colitis in mice through improving intestinal barrier and inhibiting inflammation and the underlying mechanism involves AMPK activation and JAK2/STAT3 inhibition.

Tracking the therapeutic efficacy of a ketone mono ester and ß-hydroxybutyrate for ulcerative colitis in rats: New perspectives.

Ulcerative colitis (UC) is an inflammatory condition that affects the colon's lining and increases the risk of colon cancer. Despite ongoing research, there is no identified cure for UC. The recognition of NLRP3 inflammasome activation in the pathogenesis of UC has gained widespread acceptance. Notably, the ketone body ß-hydroxybutyrate inhibits NLRP3 demonstrating its anti-inflammatory properties. Additionally, BD-AcAc 2 is ketone mono ester that increases ß-hydroxybutyrate blood levels. It has the potential to address the constraints associated with exogenous ß-hydroxybutyrate as a therapeutic agent, including issues related to stability and short duration of action. However, the effects of ß-hydroxybutyrate and BD-AcAc 2 on colitis have not been fully investigated. This study found that while both exogenous ß-hydroxybutyrate and BD-AcAc 2 produced the same levels of plasma ß-hydroxybutyrate, BD-AcAc 2 demonstrated superior effectiveness in mitigating dextran sodium sulfate-induced UC in rats. The mechanism of action involves modulating the NF-κB signaling, inhibiting the NLRP3 inflammasome, regulating antioxidant capacity, controlling tight junction protein expression and a potential to inhibit apoptosis and pyroptosis. Certainly, BD-AcAc 2's anti-inflammatory effects require more than just increasing plasma ß-hydroxybutyrate levels and other factors contribute to its efficacy. Local ketone concentrations in the gastrointestinal tract, as well as the combined effect of specific ketone bodies, are likely to have contributed to the stronger protective effect observed with ketone mono ester ingestion in our experiment. As a result, further investigations are necessary to fully understand the mechanisms of BD-AcAc 2 and optimize its use.

Both viable Bifidobacterium longum subsp. infantis B8762 and heat-killed cells alleviate the intestinal inflammation of DSS-induced IBD rats.

In view of the safety concerns of probiotics, more and more attention is paid to the beneficial effects of dead probiotics cells. Herein, we investigated and compared the alleviation effects of viable Bifidobacterium longum subsp. infantis B8762 (B. infantis B8762) and its heat-killed cells on dextran sodium sulfate (DSS)-induced inflammatory bowel disease (IBD) rats. Four groups of rats (n = 12 per group) were included: normal control, DSS-induced colitis rats without bacterial administration (DSS), DSS-induced colitis rats with viable B. infantis B8762 administration (VB8762), and DSS-induced colitis rats with dead B. infantis B8762 administration (DB8762). Our results showed that both VB8762 and DB8762 administration exerted significant protective effects on DSS-induced IBD rats, as evidenced by a reduction in mortality, disease activity index score, body weight loss, as well as decreased histology score, which were companied by a significant decrease in serum pro-inflammatory factors compared with DSS group, and a stronger effect on modulating the fecal microbiota alpha-diversity and beta-diversity compared with DSS group. Additionally, the fecal metabolome results showed that both VB8762 and DB8762 interventions indeed altered the fecal metabolome profile and related metabolic pathways of DSS-induced IBD rats. Therefore, given the alleviation effects on colitis, the DB8762 can be confirmed to be a postbiotic. Overall, our findings suggested that VB8762 and DB8762 had similar ability to alleviate IBD although with some differences. Due to the minimal safety concern of postbiotics, we propose that the postbiotic DB8762 could be a promising alternative to probiotics to be applied in the prevention and treatment of IBDs.IMPORTANCEInflammatory bowel disease (IBD) has emerged as a global disease because of the worldwide spread of western diets and lifestyles during industrialization. Up to now, many probiotic strains are used as a modulator of gut microbiota or an enhancer of gut barrier to alleviate or cure IBD. However, there are still many issues of using probiotics, which were needed to be concerned about, for instance, safety issues in certain groups like neonates and vulnerable populations, and the functional differences between viable and dead microorganisms. Therefore, it is of interest to investigate the beneficial effects of dead probiotics cells. The present study proved that both viable Bifidobacterium longum subsp. infantis B8762 and heat-killed cells could alleviate dextran sodium sulfate-induced colitis in rats. The findings help to support that some heat-killed probiotics cells can also exert relevant biological functions and can be used as a postbiotic.

Rauwolfia polysaccharide can inhibit the progress of ulcerative colitis through NOS2-mediated JAK2/STAT3 pathway.

BACKGROUND: Ulcerative colitis (UC) is an inflammatory disease of the digestive tract. Rauwolfia polysaccharide (Rau) has therapeutic effects on colitis in mice, but its mechanism of action needs to be further clarified. In the study, we explored the effect of Rau on the UC cell model induced by Lipopolysaccharide (LPS). METHODS: We constructed a UC cell model by stimulating HT-29 cells with LPS. Dextran sodium sulfate (DSS) was used to induce mice to construct an animal model of UC. Subsequently, we performed Rau administration on the UC cell model. Then, the therapeutic effect of Rau on UC cell model and was validated through methods such as Cell Counting Kit-8 (CCK8), Muse, Quantitative real­time polymerase chain reaction (RT-qPCR), Western blotting, and Enzyme-linked immunosorbent assay (ELISA). RESULTS: The results showed that Rau can promote the proliferation and inhibit the apoptosis of the HT-29 cells-induced by LPS. Moreover, we observed that Rau can inhibit the expression of NOS2/JAK2/STAT3 in LPS-induced HT-29 cells. To further explore the role of NOS2 in UC progression, we used siRNA technology to knock down NOS2 and search for its mechanism in UC. The results illustrated that NOS2 knockdown can promote proliferation and inhibit the apoptosis of LPS-induced HT-29 cells by JAK2/STAT3 pathway. In addition, in vitro and in vivo experiments, we observed that the activation of the JAK2/STAT3 pathway can inhibit the effect of Rau on DSS-induced UC model. CONCLUSION: In short, Rauwolfia polysaccharide can inhibit the progress of ulcerative colitis through NOS2-mediated JAK2/STAT3 pathway. This study provides a theoretical clue for the treatment of UC by Rau.

Alkaline sphingomyelinase deficiency impairs intestinal mucosal barrier integrity and reduces antioxidant capacity in dextran sulfate sodium-induced colitis.

BACKGROUND: Ulcerative colitis is a chronic inflammatory disease of the colon with an unknown etiology. Alkaline sphingomyelinase (alk-SMase) is specifically expressed by intestinal epithelial cells, and has been reported to play an anti-inflammatory role. However, the underlying mechanism is still unclear. AIM: To explore the mechanism of alk-SMase anti-inflammatory effects on intestinal barrier function and oxidative stress in dextran sulfate sodium (DSS)-induced colitis. METHODS: Mice were administered 3% DSS drinking water, and disease activity index was determined to evaluate the status of colitis. Intestinal permeability was evaluated by gavage administration of fluorescein isothiocyanate dextran, and bacterial translocation was evaluated by measuring serum lipopolysaccharide. Intestinal epithelial cell ultrastructure was observed by electron microscopy. Western blotting and quantitative real-time reverse transcription-polymerase chain reaction were used to detect the expression of intestinal barrier proteins and mRNA, respectively. Serum oxidant and antioxidant marker levels were analyzed using commercial kits to assess oxidative stress levels. RESULTS: Compared to wild-type (WT) mice, inflammation and intestinal permeability in alk-SMase knockout (KO) mice were more severe beginning 4 d after DSS induction. The mRNA and protein levels of intestinal barrier proteins, including zonula occludens-1, occludin, claudin-3, claudin-5, claudin-8, mucin 2, and secretory immunoglobulin A, were significantly reduced on 4 d after DSS treatment. Ultrastructural observations revealed progressive damage to the tight junctions of intestinal epithelial cells. Furthermore, by day 4, mitochondria appeared swollen and degenerated. Additionally, compared to WT mice, serum malondialdehyde levels in KO mice were higher, and the antioxidant capacity was significantly lower. The expression of the transcription factor nuclear factor erythroid 2-related factor 2 (Nrf2) in the colonic mucosal tissue of KO mice was significantly decreased after DSS treatment. mRNA levels of Nrf2-regulated downstream antioxidant enzymes were also decreased. Finally, colitis in KO mice could be effectively relieved by the injection of tertiary butylhydroquinone, which is an Nrf2 activator. CONCLUSION: Alk-SMase regulates the stability of the intestinal mucosal barrier and enhances antioxidant activity through the Nrf2 signaling pathway.

Sarcandra glabra (Thunb.) Nakai alleviates DSS-induced ulcerative colitis by promoting restitution, restoring barrier function, and modulating IL-17/Notch1/FoxP3 pathway in intestinal cells.

ETHNOPHARMACOLOGICAL RELEVANCE: Sarcandra glabra is officially named Zhong Jie Feng as a traditional medicine. In the nationality of Yao and Zhuang, it has been used to treat digestive diseases like stomachache and dysentery. Similarly, in Dai nationality, it has been used to treat intestinal diseases like gastric ulcers. However, the effect and mechanism of S. glabra on experimental ulcerative colitis (UC) are known. AIM OF STUDY: The main objective of this study was to investigate the effect and mechanism of S. glabra on experimental UC. MATERIALS AND METHODS: The chemical components in the water extract of S. glabra (ZJF) were analyzed by UPLC-MS/MS method. The HCoEpiC cell line was used to assess the promotive effect on intestinal proliferation and restitution. RAW264.7 cells were used to assess the in vitro anti-inflammatory effect of ZJF. The 3% DSS-induced colitis model was used to evaluate the in vivo effect of ZJF (4.5 g/kg and 9.0 g/kg). Mesalazine (0.5 g/kg) was used as the positive drug. ELISA, RT-qPCR, Western blot, and multiplex immunohistochemical experiments were used to test gene levels in the colon tissue. The H&E staining method was used to monitor the pathological changes of colon tissue. TUNEL assay kit was used to detect apoptosis of epithelial colonic cells. RESULTS: ZJF could alleviate the DSS-caused colitis in colon tissues, showing a comparative effect to that of the positive drug mesalazine. Mechanism study indicated that ZJF could promote normal colonic HCoEpiC cell proliferation and restitution, inhibit overexpression of pro-inflammatory cytokines, restore the M1/M2 ratio, decrease epithelial colonic cell apoptosis, rescue tight junction protein levels, and modulate IL-17/Notch1/FoxP3 pathway to treat experimental UC. CONCLUSION: Our results indicated that S. glabra can promote intestinal cell restitution, balance immune response, and modulate IL-17/Notch1/FoxP3 pathway to treat experimental UC.

Dermal injury drives a skin to gut axis that disrupts the intestinal microbiome and intestinal immune homeostasis in mice.

The composition of the microbial community in the intestine may influence the functions of distant organs such as the brain, lung, and skin. These microbes can promote disease or have beneficial functions, leading to the hypothesis that microbes in the gut explain the co-occurrence of intestinal and skin diseases. Here, we show that the reverse can occur, and that skin directly alters the gut microbiome. Disruption of the dermis by skin wounding or the digestion of dermal hyaluronan results in increased expression in the colon of the host defense genes Reg3 and Muc2, and skin wounding changes the composition and behavior of intestinal bacteria. Enhanced expression Reg3 and Muc2 is induced in vitro by exposure to hyaluronan released by these skin interventions. The change in the colon microbiome after skin wounding is functionally important as these bacteria penetrate the intestinal epithelium and enhance colitis from dextran sodium sulfate (DSS) as seen by the ability to rescue skin associated DSS colitis with oral antibiotics, in germ-free mice, and fecal microbiome transplantation to unwounded mice from mice with skin wounds. These observations provide direct evidence of a skin-gut axis by demonstrating that damage to the skin disrupts homeostasis in intestinal host defense and alters the gut microbiome.

Myeloid Cell-Derived IL-1 Signaling Damps Neuregulin-1 from Fibroblasts to Suppress Colitis-Induced Early Repair of the Intestinal Epithelium.

Neuregulin-1 (Nrg1, gene symbol: Nrg1), a ligand of the ErbB receptor family, promotes intestinal epithelial cell proliferation and repair. However, the dynamics and accurate derivation of Nrg1 expression during colitis remain unclear. By analyzing the public single-cell RNA-sequencing datasets and employing a dextran sulfate sodium (DSS)-induced colitis model, we investigated the cell source of Nrg1 expression and its potential regulator in the process of epithelial healing. Nrg1 was majorly expressed in stem-like fibroblasts arising early in mouse colon after DSS administration, and Nrg1-Erbb3 signaling was identified as a potential mediator of interaction between stem-like fibroblasts and colonic epithelial cells. During the ongoing colitis phase, a significant infiltration of macrophages and neutrophils secreting IL-1ß emerged, accompanied by the rise in stem-like fibroblasts that co-expressed Nrg1 and IL-1 receptor 1. By stimulating intestinal or lung fibroblasts with IL-1ß in the context of inflammation, we observed a downregulation of Nrg1 expression. Patients with inflammatory bowel disease also exhibited an increase in NRG1+IL1R1+ fibroblasts and an interaction of NRG1-ERBB between IL1R1+ fibroblasts and colonic epithelial cells. This study reveals a novel potential mechanism for mucosal healing after inflammation-induced epithelial injury, in which inflammatory myeloid cell-derived IL-1ß suppresses the early regeneration of intestinal tissue by interfering with the secretion of reparative neuregulin-1 by stem-like fibroblasts.

Flavokawain B inhibits NF-κB inflammatory signaling pathway activation in inflammatory bowel disease by targeting TLR2.

Inflammatory bowel disease (IBD) is characterized by recurrent inflammatory reactions in the intestinal mucosa, including ulcerative colitis (UC) and Crohn's disease (CD). The expression of Toll-like receptor 2 (TLR2) has been observed to increase during the progression of IBD. Flavokawain B (FKB), a natural chalcone with potent anti-inflammatory activity, exerts its effects through inhibition of the NF-κB pathway. In this study, we aimed to investigate the effects and mechanisms of FKB targeting TLR2 in IBD. C57BL/6 J mice were treated with 2.5% dextran sulfate sodium (DSS) for 7 days, with administration of FKB or TLR2 inhibitor C29 starting on day 2 to establish the model of IBD. In vitro, bone marrow-derived macrophages (BMDMs) were stimulated with the TLR2 agonist Pam3CSK4 to explore the therapeutic effect of FKB and its pharmacological mechanism. Compared with the model group, the FKB-treated group showed significant reductions in colitis-related injuries in the IBD mouse model, including weight gain, increased colon length and reduced inflammation. FKB decreased the formation of TLR2-MyD88 complex by targeting TLR2, leading to suppression of downstream NF-κB signaling pathway. Similar therapeutic effects were observed in the C29-treated group. Additionally, in vitro data suggested that FKB exerted its anti-inflammatory effect by targeting TLR2 and inhibiting Pam3CSK4-induced activation of the NF-κB pathway. The anti-inflammatory effects of FKB were demonstrated through drug affinity responsive target stability assay and cellular thermal shift assay, revealing its binding affinity to TLR2. By inhibiting the activation of the TLR2/NF-κB signaling pathway, FKB effectively prevented DSS-induced IBD and exhibited promising potential as a therapeutic candidate for IBD treatment.

Biochanin a ameliorates DSS-induced ulcerative colitis by improving colonic barrier function and protects against the development of spontaneous colitis in the Muc2 deficient mice.

There is an increasing appreciation that colonic barrier function is closely related to the development and progression of colitis. The mucus layer is a crucial component of the colonic barrier, responsible for preventing harmful bacteria from invading the intestinal epithelium and causing inflammation. Furthermore, a defective mucus barrier is also a significant characteristic of ulcerative colitis (UC). Biochanin A (BCA), an isoflavonoid, has garnered increasing interest due to its significant biological activities. However, the impact of BCA on UC has not been reported yet. In this study, we used a dextran sodium sulfate (DSS)-induced ulcerative colitis model and the Muc2 deficient (Muc2-/-) mice spontaneous colitis model to explore the mechanisms of BCA in the treatment of UC. Here, we verified that DSS-induced UC was observably attenuated and spontaneous colitis in Muc2-/- mice was relieved by BCA. Treatment with BCA improved colitis-related symptoms and reduced intestinal permeability by upregulating the levels of goblet cells and tight junction (TJ) proteins. In addition, we confirmed that BCA promotes autophagy through the AMP-activated protein kinase (AMPK)/mammalian target of rapamycin (mTOR)/Unc-51-like kinase 1 (ULK1) pathway, thereby alleviating DSS-induced UC. In addition, the administration of BCA was able to reduce apoptosis and promote proliferation by suppressing Cleaved Caspase-3 (Cleaved Cas-3) expression, and increasing PCNA and Ki67 levels. Further research revealed that BCA treatment ameliorated spontaneous colitis and alleviated epithelial damage in Muc2-/- mice by restoring the intestinal barrier and promoting autophagy. Our results demonstrated that BCA alleviated UC by enhancing intestinal barrier function and promoting autophagy. These findings indicate that BCA may be a novel treatment alternative for UC.

Tropomyosin 2 Regulates Tumor Cell Proliferation, Immune Suppression, and Activation of the JNK Signaling Pathway in Colitis-Associated Cancer (CAC).

BACKGROUND: Tropomyosin 2 (TPM2) has been linked to the advancement of various tumor types, exhibiting distinct impacts on tumor progression. In our investigation, the primary objective was to identify the potential involvement of TPM2 in the development of colitis-associated cancer (CAC) using a mice model. METHODS: This study used lentiviral vector complex for TPM2 knockdown (sh-TPM2) and the corresponding negative control lentiviral vector complex (sh-NC) for genetic interference in mice. CAC was induced in mice using azoxymethane (AOM) and dextran sulfate sodium salt (DSS). This study included 6 groups of mice models: Control, Control+sh-NC, Control+sh-TPM2, CAC, CAC+sh-NC, and CAC+sh-TPM2. Subsequently, colon tissues were collected and assessed using quantitative reverse transcription-polymerase chain reaction (qRT-PCR) for TPM2 mRNA levels and flow cytometry for infiltrating immune cells. Tumor number, size, and weight within colon tissues from CAC mice were measured and recorded. The hematoxylin-eosin staining was used for observing tissue pathology changes. The intestinal epithelial cells (IECs) were isolated and analyzed for cell proliferation. This analysis included examining the levels of 5-bromo-2-deoxyuridine (BrdU) and Ki-67 using immunohistochemistry. Additionally, the mRNA levels of proliferating cell nuclear antigen (PCNA) and Ki-67 were detected by qRT-PCR. This study also investigated the activation of the c-Jun N-terminal kinase (JNK) pathway using western blot analysis. Immunogenicity analyses were conducted using immunohistochemistry for F4/80 and flow cytometry. RESULTS: In 8-week-old mice, AOM injections and three cycles of DSS treatment induced TPM2 upregulation in tumor tissues compared to normal tissues (p < 0.05). Fluorescence-activated cell sorting (FACS)-isolated lamina CAC adenomas revealed macrophages and dendritic cells as primary TPM2 contributors (p < 0.001). Lentiviral TPM2 gene knockdown significantly reduced tumor numbers and sizes in CAC mice (p < 0.01, and p < 0.001), without invasive cancer cells. TPM2 suppression resulted in decreased IEC proliferation (p < 0.001) and reduced PCNA and Ki-67 expression (p < 0.05). Western blot analysis indicated reduced JNK pathway activation in TPM2-knockdown CAC mice (p < 0.05, p < 0.001). TPM2 knockdown decreased tumor-associated macrophage infiltration (p < 0.01) and increased CD3+ and CD8+ T cells (p < 0.01, and p < 0.001), with increased levels of regulator of inflammatory cytokines (CD44+, CD107a+) (p < 0.01, and p < 0.001), decreased levels of PD-1+ and anti-inflammatory factor (IL10+) (p < 0.01, and p < 0.001). CONCLUSIONS: Our results demonstrated that TPM2 knockdown suppressed the proliferation of CAC IECs, enhanced immune suppression on CAC IECs, and inhibited the JNK signaling pathway within the framework of CAC. These findings suggest TPM2 can serve as a potential therapeutic target for CAC treatment.

Mannose enhances intestinal immune barrier function and dextran sulfate sodium salt-induced colitis in mice by regulating intestinal microbiota.

Background: Inflammatory bowel disease (IBD) greatly affects human quality of life. Mannose has been reported to be used to treat IBD, but the mechanism is currently unknown. Methods: C57/BL mice were used as research subjects, and the mouse acute colitis model was induced using dextran sulfate sodium salt (DSS). After oral administration of mannose, the body weights and disease activity index (DAI) scores of the mice were observed. The colon lengths, histopathological sections, fecal content microbial sequencing, colon epithelial inflammatory genes, and tight junction protein Occludin-1 expression levels were measured. We further used the feces of mice that had been orally administered mannose to perform fecal bacterial transplantation on the mice with DSS-induced colitis and detected the colitis-related indicators. Results: Oral administration of mannose increased body weights and colon lengths and reduced DAI scores in mice with DSS-induced colitis. In addition, it reduced the expression of colon inflammatory genes and the levels of serum inflammatory factors (TNF-α, IL-6, and IL-1ß), further enhancing the expression level of the colonic Occludin-1 protein and alleviating the toxic response of DSS to the intestinal epithelium of the mice. In addition, gut microbial sequencing revealed that mannose increased the abundance and diversity of intestinal flora. Additionally, after using the feces of the mannose-treated mice to perform fecal bacterial transplantation on the mice with DSS-induced colitis, they showed the same phenotype as the mannose-treated mice, and both of them alleviated the intestinal toxic reaction induced by the DSS. It also reduced the expression of intestinal inflammatory genes (TNF-α, IL-6, and IL-1ß) and enhanced the expression level of the colonic Occludin-1 protein. Conclusion: Mannose can treat DSS-induced colitis in mice, possibly by regulating intestinal microorganisms to enhance the intestinal immune barrier function and reduce the intestinal inflammatory response.

Gigantol ameliorates DSS-induced colitis via suppressing ß2 integrin mediated adhesion and chemotaxis of macrophage.

ETHNOPHARMACOLOGICAL RELEVANCE: Dendrobium, recognized as "Shihu" in traditional Chinese medicine, holds a rich history of medicinal utilization documented in the Chinese Pharmacopoeia. Ancient texts like "Shen Nong Ben Cao Jing" extol Dendrobium's virtues as a superior herbal medicine fortifying "Yin" and invigorating the five viscera. Dendrobium is extensively employed for the treatment of gastrointestinal inflammatory disorders, showcasing significant therapeutic efficacy, particularly against ulcerative colitis (UC), within the realm of Chinese ethnopharmacology. Dendrobium plays crucial pharmacological roles due to its rich content of polysaccharides, alkaloids, phenanthrenes, and bibenzyls. Gigantol, a prominent bibenzyl compound, stands out as one of the most vital active constituents within Dendrobium, the gigantol content of Dendrobium leaves can reach approximately 4.79 µg/g. Its significance lies in being recognized as a noteworthy anti-inflammatory compound derived from Dendrobium. AIM OF THE STUDY: Given the pivotal role of gigantol as a primary active substance in Dendrobium, the therapeutic potential of gigantol for gastrointestinal diseases remains enigmatic. Our present investigation aimed to evaluate the therapeutic effects of gigantol on dextran sulfate sodium (DSS)-induced colitis and reveal its potential mechanism in countering UC activity. MATERIALS AND METHODS: The protective efficacy of gigantol against colitis was assessed by examining the histopathological changes and conducting biochemical analyses of colon from DSS-challenged mice. Assessments focused on gigantol's impact on improving the intestinal epithelial barrier and its anti-inflammatory effects in colonic tissues of colitis mice. Investigative techniques included the exploration of the macrophage inflammatory signaling pathway via qPCR and Western blot analyses. In vitro studies scrutinized macrophage adhesion, migration, and chemotaxis utilizing transwell and Zigmond chambers. Furthermore, F-actin and Rac1 activation assays detailed cellular cytoskeletal remodeling. The potential therapeutic target of gigantol was identified and validated through protein binding analysis, competitive enzyme-linked immunosorbent assay (ELISA), cellular thermal shift assay (CETSA), and drug affinity responsive target stability (DARTS) assay. The binding sites between gigantol and its target were predicted via molecular docking. RESULTS: Gigantol ameliorated symptoms of DSS-induced colitis, rectified damage to the intestinal barrier, and suppressed the production of pro-inflammatory cytokines in colonic tissues. Intriguingly, gigantol significantly curtailed NF-κB signaling activation in the colons of DSS-induced colitis mice. Notably, gigantol impaired the ß2 integrin-dependent adhesion and migratory capacity of RAW264.7 cells. Moreover, gigantol notably influenced the cytoskeleton remodeling of RAW264.7 cells by suppressing Vav1 phosphorylation and Rac1 activation. Mechanistically, gigantol interacted with ß2 integrin, subsequently diminishing binding affinity with intercellular adhesion molecule-1 (ICAM-1). CONCLUSIONS: In conclusion, these findings elucidate that gigantol ameliorates DSS-induced colitis by antagonizing ß2 integrin-mediated macrophage adhesion, migration, and chemotaxis, thus it may impede macrophage recruitment and infiltration into colonic tissues. This study suggests that gigantol shows promise as a viable candidate for clinical colitis therapy.