Dextran Sodium Sulfate-induced Colitis Model Research Articles

Oligosaccharide-dependent anti-inflammatory role of galectin-1 for macrophages in ulcerative colitis.

Galectin-1 plays a protective role against colitis by binding with polylactosamine structures on macrophages in β-1,4-galactosyltransferase I-deficient mice, but the precise function of galectin-1 remains unknown. In the present study, we investigated the anti-inflammatory role of galectin-1 on macrophages to ameliorate ulcerative colitis in both animal model and human tissue samples. The expression of galectin-1 in colonic tissues of ulcerative colitis patients was evaluated by immunohistochemistry. Cytokine production of mouse bone marrow-derived macrophages (BMDMs) cultured with galectin-1 was investigated. Galectin-1 binding capacity and polylactosamine expression in macrophages stimulated with lipopolysaccharides were evaluated by flow cytometry. BMDMs cultured with galectin-1 were transferred into Recombination activating gene (Rag) 2-/- mice, and the severity of the dextran sodium sulfate-induced colitis model was investigated. Furthermore, RNA sequencing was performed to characterize macrophages treated with galectin-1. In ulcerative colitis patients, tissue expression of galectin-1was decreased in inflamed mucosa compared with non-inflamed mucosa. Galectin-1 induced interleukin-10 production in BMDMs, and the interleukin-10 production was abrogated by lactose, which inhibits the interaction of oligosaccharide-galectin binding. Dextran sodium sulfate colitis was significantly ameliorated in Rag2-/- mice undergoing galectin-1-treated BMDM transfer compared with those undergoing vehicle-treated BMDM transfer. RNA sequencing revealed that treatment with galectin-1 increased the expression of CCAAT/enhancer binding protein β and CD163, but decreased the expression of CD80 on BMDMs. Galectin-1, whose expression is decreased in the inflamed mucosa of ulcerative colitis patients, can ameliorate murine colitis by conferring oligosaccharide-dependent anti-inflammatory properties to macrophages.

Molecular and Microbial Signatures Predictive of Prebiotic Action of Neoagarotetraose in a Dextran Sulfate Sodium-Induced Murine Colitis Model.

Neoagarotetraose (NT), a hydrolytic product of agar by β-agarase, is known to possess bioactive properties. However, the mechanisms via which NT alleviates intestinal inflammation remain unknown. In this study, a dextran sulfate sodium (DSS)-induced murine model was developed to evaluate the effect of NT on gut microbiome and microbial metabolism using 16S rRNA gene sequencing and untargeted metabolomics. Our data demonstrate that NT ingestion improved gut integrity and inflammation scores. NT reversed the abundance of Proteobacteria from an elevated level induced by DSS and significantly increased the abundance of Verrucomicrobia. Further, NT significantly increased the abundance of Akkermansia and Lactobacillus and concomitantly decreased that of Sutterella, which were among the important features identified by random forests analysis contributing to classification accuracy for NT supplementation. A microbial signature consisting of Adlercreutzia (denominator) and Turicibacter (numerator) predicted the NT supplementation status. Moreover, NT significantly modulated multiple gut metabolites, particularly those related to histidine, polyamine and tocopherol metabolism. Together, our findings provided novel insights into the mechanisms by which NT modulated the gut microbiome and metabolome and should facilitate the development of NT as a potent prebiotic for colitis management.

Anti-Inflammatory Activity and Mechanism of Hydrostatin-SN1 From Hydrophis cyanocinctus in Interleukin-10 Knockout Mice.

Biopeptides derived from marine species have garnered significant research interest owing to their anti-inflammatory, antibacterial, and anticancer activities. In our previous study, Hydrostatin-SN1, a bioactive peptide extracted from the Hydrophis cyanocinctus venom gland T7 phage display library, demonstrated anti-inflammatory activity in a dextran sulfate sodium-induced murine colitis model. In this study, we investigated the anti-inflammatory activity and the underlying mechanism of Hydrostatin-SN1 in lipopolysaccharide (LPS)-induced bone marrow-derived macrophage (BMDM) cells and interleukin (IL)-10 knockout mice. The results showed that Hydrostatin-SN1 inhibited phosphorylation of JNK, ERK1/2, and p38 and decreased the mRNA expression of tumor necrosis factor-α (TNF-α), IL-6, and IL-1β in LPS-stimulated BMDM cells in a dose-dependent manner. In LPS-induced acute shock model, a significant higher survival rate of Hydrostatin-SN1-treated mice was observed. Furthermore, Hydrostatin-SN1 reduced body weight loss, decreased disease activity index, reduced spleen index, prevented histological injury, and inhibited the expression of IL-β and phosphorylation of JNK, ERK1/2, and p38 in the colon tissue of IL-10 knockout mice. Additionally, the positive expression rate of TNF-α in mice colon was decreased. Overall, our results suggest that Hydrostatin-SN1 has significant anti-inflammatory effects, both in vitro and in vivo.

The effect of selected Lactobacillus strains on dextran sulfate sodium-induced mouse colitis model.

Inflammatory bowel disease (IBD) comprises two major illnesses: Crohn's disease (CD) and ulcerative colitis (UC). Dextran sulfate sodium (DSS) mouse colitis model has been used in understanding the mechanism of IBD. This study was conducted to examine selected Lactobacillus spp. as potential IBD treatment in the DSS-induced animal model. Balb/c mice were used and colitis was induced by adding 5% dextran sodium sulfate into the drinking water for 8 days. Colon length, disease activity index (DAI) and histological analysis were measured as markers of inflammation in DSS colitis mice. The majority of the Lactobacillus species significantly prevented the shortening of the colon length compared with the DSS group. The DAI scores of mice were significantly reduced following usage of four Lactobacillus strains included: Lactobacillus plantarum 03 and 06, Lactobacillus brevis 02 and Lactobacillus rhamnosus 01. The histological analysis exhibited that oral administration of Lactobacillus strains had therapeutic effects on mice colitis. L. plantarum and L. brevis showed better therapeutic effect against DSS-induced acute colitis mice. The probiotic activities of these three isolates indicated that the probiotic effects were strain specific and none of these useful bacteria could exhibit all of the valued probiotic properties simultaneously.

Promotion of wound healing by acetate in murine colonic epithelial cell via c-Jun N-terminal kinase activation.

Mucosal healing is an important clinical goal in patients with inflammatory bowel disease. Recently, short-chain fatty acids (SCFAs) have been reported to have multifaceted effects to host. However, the effects of SCFAs on wound healing in intestinal epithelial cells are unclear. In the present study, we investigated the effects of acetate, one of the major SCFAs, on the wound healing of murine colonic epithelial cells. Young adult mouse colonic epithelial cells were used to determine the effect of acetate using wound healing assay. Mitogen-activated protein kinase and Rho kinase inhibitor were used to elucidate intracellular signal of wound healing treated with acetate. Meanwhile, Rho activation assays were utilized to measure Rho activation levels. To assess in vivo effects, C57B6 mice with dextran sodium sulfate for 7days were treated with enema administration of acetate for 7days. Body weight, disease activity index, colon length, and mucosal break ratio in histology were examined. Acetate enhanced wound healing and fluorescence intensity of actin stress fiber compared with control. These effects were canceled with pretreatment of c-Jun N-terminal kinase (JNK) inhibitor or Rho kinase inhibitor. Furthermore, JNK inhibitor reduced the activation of Rho induced by acetate. In the dextran sodium sulfate-induced colitis model, the mice with enema treatment of acetate significantly exhibited recovery. In this study, we demonstrated that acetate promoted murine colonic epithelial cell wound healing via activation of JNK and Rho signaling pathways. These findings suggested that acetate could have applications as a therapeutic agent for patients with intestinal mucosal damage, such as inflammatory bowel disease.

Integrating Pharmacology and Microbial Network Analysis with Experimental Validation to Reveal the Mechanism of Composite Sophora Colon-Soluble Capsule against Ulcerative Colitis.

Ulcerative colitis (UC) has multifactorial pathogenesis that acts synergistically, such as immune system dysregulation and expansion of infectious gut microbiota. Therefore, a multicomponent treatment derived from Chinese herbal medicine that interacts with multiple targets synergistically is needed. Composite sophora colon-soluble capsule (CSCC) is a Chinese herbal formula that has shown therapeutic efficacy against UC in randomized clinical trials. However, its bioactive components and potential target genes against UC remain unclear. Here, we used a network pharmacology approach to detect component-target-pathway interactions of CSCC against UC. A total of 29 gene targets, 91 bioactive components, and 20 enriched pathways of CSCC were identified. The IL-17 signaling pathway activated by infectious gastrointestinal microbes and predicted by the network analysis to be a major pathway modulated by CSCC against UC was studied in a dextran sulfate sodium-induced colitis model. CSCC showed remarkable efficacy against UC with respect to the attenuation of colon length, body weight loss, and disease activity index through gut microbiota recovery and intestinal immune homeostasis. The rectal administration of CSCC reduced the numbers of Th17 cells isolated from both mesenteric lymph nodes and lamina propria mononuclear cells and the levels of IL-17A, IL-6, IL-1β, and TNF-α. Additionally, the percentage of Treg cells and the levels of their hallmark cytokines were upregulated. Rectal administration of CSCC led to microbiota regulation with a significant correlation between suppression of Verrucomicrobiaceae and Ruminococcaceae, as well as the elevation of Lactobacillaceae, and CSCC administration via microbiome correlation heatmaps and cooccurrence network analysis at multiple time points. Thus, our study presents an effective herbal formula, CSCC, for UC treatment and explores its components and mechanisms of efficacy through the examination of gut microbiota and hallmark cytokines in the IL-17 pathway.

Benzofuran and pyrrole derivatives as cannabinoid receptor modulators with in vivo efficacy against ulcerative colitis.

Aim: Highlighting the need for effective therapies for the treatment of ulcerative colitis, novel series of potential CB2 modulators (benzofuran and pyrrole carboxamides) were developed and tested for their functional activities on CB1/CB2 receptors. Results: In the benzofuran series, the cannabinoid (CB) receptor selectivity and the functional profile were dependent on the nature of the amide substituent and the position of the methoxy group, meanwhile the pyrrole derivatives, displayed an exclusive selectivity to the CB2 receptor and a functionality that is controlled by the nature of the pyrrole nitrogen substituent. Conclusion: Remarkably, we succeeded to develop potent and selective pyrrole-based CB2 receptor agonists, represented by compound 25a, which also demonstrated an exquisite anti-inflammatory effect in a dextran sodium sulfate-induced colitis model in mice.

LC-MS-based metabolomics analysis of Berberine treatment in ulcerative colitis rats

Inflammatory bowel disease (IBD) is often accompanied by metabolic imbalance and Berberine can relieve the symptoms of IBD, but the mechanism is still unclear. To explore the relationship between IBD, metabolism and Berberine, dextran sulfate sodium-induced ulcerative colitis (UC) model was built and urine and feces samples were analyzed with ultra-performance liquid chromatography combined with quadrupole-time-of-flight mass spectrometry, followed by multivariate statistical analyses. Targeted metabolomics was applied to verify and supplement the result of amino acids tested by non-targeted metabolomics. The study found that Berberine could ameliorate UC and improve metabolic disorders. The level of 4 metabolites increased and 35 decreased in urine and these metabolites mainly belong to amino acid, glucide, organic acid and purine. Besides, Berberine could reduce the level of 5 metabolites and raise the level of 7 metabolites in feces, which mainly belong to amino acid and lipid. Additionally, these altered metabolites were mainly related to amino acids metabolism, purine metabolism, vitamin metabolism, lipid metabolism and citrate cycle pathways. Furthermore, microbiome metabolism may be regulated by Berberine in UC. In general, this study provides a useful approach for exploring the mechanism of Berberine in the treatment of UC from the perspective of metabolomics.

Preconditioning with interleukin-1 beta and interferon-gamma enhances the efficacy of human umbilical cord blood-derived mesenchymal stem cells-based therapy via enhancing prostaglandin E2 secretion and indoleamine 2,3-dioxygenase activity in dextran sulfate sodium-induced colitis.

Preconditioning with inflammatory cytokines has improved mesenchymal stem cells characteristics, including differentiation and immunomodulating functions. In this study, we developed a preconditioning combination strategy using interleukin-1beta (IL-1β) and interferon-gamma (IFN-γ) to enhance the immuneregulatory ability of human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs). Our results showed that hUCB-MSCs preconditioned with IL-1β and IFN-γ (primed hUCB-MSCs) created a statistically significant decrease in peripheral blood mononuclear cell proliferation, indicating that their immunosuppressive ability was increased. The secretion of PGE2, cyclooxygenase 2 mRNA expression, and indoleamine 2,3-dioxygenase (IDO) mRNA expression in primed hUCB-MSCs was significantly higher than those in the untreated hUCB-MSCs or the IL-1β or IFN-γ only treated hUCB-MSCs. When inhibitors of IDO and PGE2 were treated, peripheral blood mononuclear cell proliferation, which is inhibited by primed hUCB-MSCs, was recovered. We found that Th1 T cell differentiation was also inhibited by PGE2 and IDO in the primed hUCB-MSCs, and Tregs differentiation was increased by PGE2 and IDO in the primed hUCB-MSCs. Furthermore, the primed hUCB-MSCs as well as supernatants increase CD4+ T cells migration. We demonstrated the therapeutic effects of primed hUCB-MSCs in dextran sulfate sodium-induced colitis model. In conclusion, we have demonstrated that primed hUCB-MSCs simultaneously enhance PGE2 and IDO and greatly improve the immunoregulatory capacity of MSCs, and we have developed an optimal condition for pretreatment of MSCs for the treatment of immune diseases. Our results raise the possibility that the combination of PGE2 and IDO could be therapeutic mediators for controlling immunosuppression of MSCs.

Association of TRAP1 with infliximab-induced mucosal healing in Crohn's disease.

Anti-tumor necrosis factor (TNF) agents, such as infliximab (IFX), have been increasingly used to induce and maintain disease remission in patients with Crohn's disease (CD). Despite a considerable non-response rate, little is known about the genetic predictors of response to anti-TNF therapy in CD. Our aim in this study was to investigate the genetic factors associated with response to anti-TNF therapy in patients with CD. We performed a two-stage genome-wide association study (GWAS) to identify loci influencing the response to IFX among Korean patients with CD, comprising 42 good responders with mucosal healing and 70 non-responders. The achievement of mucosal healing was assessed by endoscopy and imaging. The functional significance of TRAP1 (TNF receptor associated protein 1) was examined using dextran sodium sulfate-induced colitis model in TRAP1 transgenic mice. The GWAS identified rs2158962, an intronic single nucleotide polymorphism (SNP) of TRAP1, significantly associated with mucosal healing (odds ratio=4.94; Pcombined =1.35×10-7 ). In the dextran sodium sulfate-induced acute colitis, TRAP1 transgenic mice showed a better response to IFX than the wild-type mice. The TRAP1 gene is associated with mucosal healing in CD patients following IFX therapy. Identifying the genetic predictors of mucosal healing to anti-TNF therapy can prevent patients from exposure to ineffective therapies.

Anti-inflammatory effects of apocynin on dextran sulfate sodium-induced mouse colitis model.

Background and aimVarious drugs have been developed for inflammatory bowel disease (IBD), but still there are limitations in the treatment due to the insufficient responses and significant adverse effects of immunosuppressant. Apocynin is an NADPH-oxidase inhibitor with established safety profiles. We aimed to investigate the protective efficacy of apocynin in IBD using chemical-induced mouse colitis model.MethodWe induced experimental colitis by administrating 5% dextran sulfate sodium (DSS) to 8-week old BALB/c mouse for 11 days. Apocynin (400 mg/kg) or sulfasalazine (150 mg/kg) were administeredduring7 days. We monitored bodyweight daily and harvested colon and spleen at day 11 to check weight and length. We also examined histopathologic change and pro-, anti-inflammatory cytokines and enzymes from harvested colons (iNOS, COX-2, TNF-α, MCP-1, p-NrF2, and HO-1).ResultApocynin significantly alleviated weight reduction induced by DSS treatment (21.64 ± 0.55 for Apocynin group vs. 20.33 ± 0.90 for DSS group, p = 0.005). Anti-inflammatory efficacy of apocynin was also shown by the recovery of colon weight and length. Histopathologic examination revealed significantly reduced inflammatory foci and erosions by apocynin treatment. Colonic expression of iNOS, COX-2, TNF-α, and MCP-1 was decreased significantly in the apocynin treated group. Anti-inflammatory mediators Nrf2 and HO-1 were activated significantly in apocynin treated mouse.ConclusionApocynin showed significant anti-inflammatory efficacy against chemically induced colonic inflammation. This study also revealed the unique action of apocynin compared to the currently prescribed drug, sulfasalazine. Given its excellent safety profile and potent efficacy with novel action mechanism, apocynin can be a new therapeutic molecule for the IBD treatment, which can be added to the currently available drugs.

Administration of Lactobacillus paracasei strains improves immunomodulation and changes the composition of gut microbiota leading to improvement of colitis in mice

We confirmed that Lactobacillus paracasei (L. paracasei) strains (KBL382, 384, 385) exhibited strong protective effects in an in vivo dextran sodium sulfate-induced colitis model. L. paracasei treatment significantly improved colitis symptoms. Among tested strains, L. paracasei KBL382-treated mice exhibited significantly lower levels of cytokines interferon gamma, interleukin (IL)-4, IL-6, tumor necrosis factor, and IL-17A. On the other hand, higher levels of anti-inflammatory cytokine IL-10 and CD4 + CD25 + Foxp3+ T regulatory cell populations in mesenteric lymph nodes were observed in mice group with L. paracasei. L. paracasei treatment clearly increased zonula occluden-1, claudin 3, and mucin 4 levels, which improved the tight junction and mucus thickness. L. paracasei-treated mice showed significantly higher bacterial diversity and changed the composition of cecal microbiota. Therefore, we suggest that L. paracasei could be a useful tool in the treatment of inflammatory bowel diseases via immunomodulation and the improvement of gut microbiota.

From Gut to Brain: Alteration in Inflammation Markers in the Brain of Dextran Sodium Sulfate-induced Colitis Model Mice.

ObjectiveNeuropsychiatric manifestations like depression and cognitive dysfunction commonly occur in inflammatory bowel disease (IBD). In the context of the brain-gut axis model, colitis can lead to alteration of brain function in a bottom-up manner. Here, the changes in the response of the hypothalamic-pituitary-adrenal axis and inflammation-related markers in the brain in colitis were studied.MethodsDextran sodium sulfate (DSS) was used to generate a mouse model of colitis. Mice were treated with DSS for 3 or 7 days and sacrificed. We analyzed the gene expression of brain-derived neurotrophic factor (BDNF), cyclo-oxygenase 2 (COX-2), and glial fibrillary acidic protein (GFAP), and the expression of GFAP, in the hippocampus, hypothalamus, and amygdala. Additionally, the levels of C-reactive protein (CRP) and serum cortisol/corticosterone were measured.ResultsAlteration of inflammatory-related markers varied depending on the brain region and exposure time. In the hippocampus, COX-2 mRNA, GFAP mRNA, and GFAP expression were upregulated during exposure to DSS. However, in the hypothalamus, COX-2 mRNA was upregulated only 3 days after treatment. In the amygdala, BDNF and COX-2 mRNAs were downregulated. CRP and corticosterone expression increased with DSS treatment at day 7.ConclusionIBD could lead to neuroinflammation in a bottom-up manner, and this effect varied according to brain region. Stress-related hormones and serum inflammatory markers, such as CRP, were upregulated from the third day of DSS treatment. Therefore, early and active intervention is required to prevent psychological and behavioral changes caused by IBD, and region-specific studies can help understand the precise mechanisms by which IBD affects the brain.

From Gut to Brain: Alteration in Inflammation Markers in the Brain of Dextran Sodium Sulfate-induced Colitis Model Mice

From Gut to Brain: Alteration in Inflammation Markers in the Brain of Dextran Sodium Sulfate-induced Colitis Model Mice

Bisphenol-A alters microbiota metabolites derived from aromatic amino acids and worsens disease activity during colitis.

Inflammatory bowel disease is a complex collection of disorders. Microbial dysbiosis as well as exposure to toxins including xenoestrogens are thought to be risk factors for inflammatory bowel disease development and relapse. Bisphenol-A has been shown to exert estrogenic activity in the colon and alter intestinal function, but the role that xenoestrogens, such as bisphenol-A , play in colonic inflammation has been previously described but with conflicting results. We investigated the ability of bisphenol-A to exacerbate colonic inflammation and alter microbiota metabolites derived from aromatic amino acids in an acute dextran sulfate sodium-induced colitis model. Female C57BL/6 mice were ovariectomized and exposed to bisphenol-A daily for 15 days. Disease activity measures include body weight, fecal consistency, and rectal bleeding. Colons were scored for inflammation, injury, and nodularity. Alterations in the levels of microbiota metabolites derived from aromatic amino acids known to reflect phenotypic changes in the gut microbiome were analyzed. Bisphenol-A exposure increased mortality and worsened disease activity as well as inflammation and nodularity scores in the middle colon region following dextran sulfate sodium exposure. Unique patterns of metabolites were associated with bisphenol-A consumption. Regardless of dextran sulfate sodium treatment, bisphenol-A reduced levels of tryptophan and several metabolites associated with decreased inflammation in the colon. This is the first study to show that bisphenol-A treatment alone can reduce microbiota metabolites derived from aromatic amino acids in the colon which may be associated with increased colonic inflammation and inflammatory bowel disease. Impact statement As rates of inflammatory bowel disease rise, discovery of the mechanisms related to the development of these conditions is important. Environmental exposure is hypothesized to play a role in etiology of the disease, as are alterations in the gut microbiome and the metabolites they produce. This study is the first to show that bisphenol-A alone alters tryptophan and microbiota metabolites derived from aromatic amino acids in a manner consistent with autoimmune diseases, specifically inflammatory bowel diseases, regardless of dextran sulfate sodium treatment. These findings indicate a potential mechanism by which bisphenol-A negatively affects gut physiology to exacerbate inflammation.

Role of MAdCAM-1-Expressing High Endothelial Venule-Like Vessels in Colitis Induced in Mice Lacking Sulfotransferases Catalyzing L-Selectin Ligand Biosynthesis.

Ulcerative colitis (UC) is a chronic inflammatory disease histologically characterized by diffuse mononuclear cell infiltrates in colonic mucosa. These inflammatory cells are considered to be recruited via high endothelial venule (HEV)-like vessels displaying mucosal addressin cell adhesion molecule 1 (MAdCAM-1), the ligand for α4β7 integrin, and/or peripheral lymph node addressin (PNAd), an L-selectin ligand. 6- O-sulfation of N-acetylglucosamine in the carbohydrate moiety of PNAd is catalyzed exclusively by N-acetylglucosamine-6- O-sulfotransferase 1 (GlcNAc6ST-1) and GlcNAc6ST-2. To determine the role of 6- O-sulfation of N-acetylglucosamine on HEV-like vessels in UC, we used a chronic dextran sulfate sodium-induced colitis model using mice deficient in both GlcNAc6ST-1 and GlcNAc6ST-2. We found that more inflammatory cells, with expression of tumor necrosis factor α, were infiltrated in double knockout mouse colitis compared with that in wild-type mice. Moreover, the number of MAdCAM-1-positive vessels was increased in double knockout mouse colitis, and these vessels were bound by E-selectin•IgM chimeras that bind to unsulfated sialyl Lewis X (sLeX). These findings suggest that interactions between MAdCAM-1 and α4β7 integrin and/or unsulfated sLeX and L-selectin may become a dominant mechanism for inflammatory cell recruitment in the absence of 6-sulfo sLeX and contribute to more severe colitis phenotypes seen in double knockout mice.

Transgenic mice specifically expressing amphiregulin in white adipose tissue showed less adipose tissue mass.

To determine adipocytokines that play a regulatory role during obesity development, we explored the genes that encode growth factors and investigated the physiological functions for adipose tissue development. Here, we isolated amphiregulin (Areg) gene whose expression was significantly up-regulated in obese adipose tissues. Areg mRNA level was positively correlated with macrophage marker gene expression in adipose tissues in vivo. Unexpectedly, Areg transgenic mice showed less adipose tissue mass with increased mRNA expression levels of Tnf-α and peroxisome proliferator-activated receptor γ coactivator 1α (Pgc-1α) and delayed white adipose tissue development during the convalescent stage in a dextran sodium sulfate-induced colitis model. This study showed that Areg mRNA expression was significantly up-regulated in obese adipose tissues and over-expression of Areg in white adipose tissue caused less adipose tissue mass.

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

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

Hydrostatin-SN1, a Sea Snake-Derived Bioactive Peptide, Reduces Inflammation in a Mouse Model of Acute Lung Injury.

Snake venom has been used for centuries as a traditional Chinese medicine. Hydrostatin-SN1 (H-SN1), a bioactive peptide extracted from the Hydrophis cyanocinctus venom gland T7 phage display library, was reported to have the ability to reduce inflammation in a dextran sulfate sodium-induced murine colitis model. In this study, we sought to investigate the inhibitory potential of H-SN1 on inflammation in a murine model of lipopolysaccharide (LPS)-induced acute lung injury (ALI), and elucidate the anti-inflammatory mechanism in LPS-stimulated RAW 264.7 cells. In vivo, C57BL/6 male mice were intratracheally instilled with LPS or physiological saline with concurrent intraperitoneal injection of H-SN1 or saline alone. Lung histopathologic changes, lung wet-to-dry weight ratio, and myeloperoxidase activity in lung tissues were assessed. Total cell number, the protein concentration, and cytokine levels were determined in the bronchial alveolar lavage fluid. In vitro, RAW 264.7 cells were treated with various concentrations of H-SN1 for 2 h followed by incubation with or without 1 μg/ml LPS for 0.5 or 24 h. The mRNA expression of inflammatory cytokines was determined via RT-PCR and protein levels in the supernatants were measured via ELISA. Extracellular-signal related kinase 1/2 (ERK1/2) and nuclear factor-κB (NF-κB) pathways were analyzed via western blot. H-SN1 improved pulmonary edema status, decreased vascular permeability, suppressed pro-inflammatory cytokine production, and lessened lung morphological injury. H-SN1 also dose-dependently inhibited the mRNA expression and release of TNF-α, IL-6, and IL-1β in LPS-stimulated RAW 264.7 cells. Moreover, H-SN1 inhibited the LPS-induced phosphorylation of ERK1/2 and the nuclear translocation of NF-κB. Our results suggest that H-SN1 could attenuate LPS-induced ALI in mice, which is associated with the anti-inflammatory effect of H-SN1. The mechanism might involve inhibiting the production of inflammatory cytokines by, at least in part, interfering with the ERK1/2 and NF-κB signaling pathways.

Iron Supplements Modulate Colon Microbiota Composition and Potentiate the Protective Effects of Probiotics in Dextran Sodium Sulfate-induced Colitis.

Iron is an important nutrient for both the host and colonizing bacteria. Oral iron supplementation may impact the composition of the microbiota and can be particularly damaging to patients suffering from inflammatory bowel disease (IBD). However, patients with IBD may require iron supplementation to treat their anemia. We fed mice with diets supplemented with ferrous sulfate at different doses (5, 50, and 500 mg of iron/kg chow) and with different iron formulations (ferrous sulfate, ferrous bisglycinate and ferric ethylenediaminetetraacetic acid [FEDTA]), and analyzed the effects on the composition of the gut microbiota by 16S ribosomal RNA gene sequencing. Using the dextran sodium sulfate (DSS)-induced colitis mouse model, we investigated the effects of iron supplementation in colitis severity, as well as the use of the probiotic Escherichia coli Nissle 1917 (EcN) in combination with iron supplementation. Iron supplementation at different doses induced shifts in the gut microbial communities and inferred metabolic pathways. However, depending on the iron formulation used in the diets, iron supplementation during dextran sodium sulfate-induced colitis was either beneficial (ferrous bisglycinate) or highly detrimental (FEDTA). Finally, the beneficial effect of the probiotic EcN in the dextran sodium sulfate-induced colitis model was potentiated by oral iron supplementation with ferrous sulfate. These results show that the iron formulations used to treat iron deficiency influence the gut microbiota and colitis in mice and suggest that distinct iron compounds may be of particular relevance to patients with IBD. In addition, the beneficial action of probiotics in IBD may be enhanced by oral iron supplementation.