Cell-free probiotic supernatant (CFS) treatment alleviates indomethacin-induced enterocolopathy in BALB/c mice by down-modulating inflammatory response and oxidative stress: potential alternative targeted treatment.

Probiotics and their metabolites appear to be a promising approach that targets both the intestinal inflammation and dysbiosis in bowel diseases. In this context, the emergence of the probiotic cell-free supernatant (CFS) has attracted more attention as a safe and targeted alternative therapy with reduced side effects. The use of nonsteroidal anti-inflammatory drugs (NSAIDs) can cause significant intestinal alterations and inflammation, leading to experimental enterocolopathy resembling Crohn disease. Therefore, we investigated the effect of CFS supplementation on the inflammation and the mucosal intestinal alterations induced by NSAIDs, indomethacin. In the current study, a murine model of intestinal inflammation was generated by the oral gavage (o.g) of indomethacin (10 mg/kg) to BALB/C mice. A group of mice treated with indomethacin was concomitantly treated orally by CFS for 5 days. The Body Health Condition index was monitored, and histological scores were evaluated. Moreover, oxidative and pro-inflammatory markers were assessed. Interestingly, we observed that CFS treatment attenuated the severity of the intestinal inflammation in our enterocolopathy model and resulted in the improvement of the clinical symptoms and the histopathological features. Notably, nitric oxide, tumor necrosis factor alpha, malondialdehyde, and myeloperoxidase levels were down-modulated by CFS supplementation. Concomitantly, an attenuation of NF-κB p65, iNOS, COX2 expression in the ileum and the colon was reported. Collectively, our data suggest that CFS treatment has a beneficial effect in experimental enterocolopathy model and could constitute a good therapeutic candidate for alleviating inflammatory responses and to maintain mucosal homeostasis during chronic and severe conditions of intestinal inflammation.

Autocrine and paracrine IL-2 signals collaborate to regulate distinct phases of CD8 T cell memory.

Differential interleukin-2 (IL-2) signaling and production are associated with disparate effector and memory fates. Whether the IL-2 signals perceived by CD8 T cells come from autocrine or paracrine sources, the timing of IL-2 signaling and their differential impact on CD8 T cell responses remain unclear. Using distinct models of germline and conditional IL-2 ablation in post-thymic CD8 T cells, this study shows that paracrine IL-2 is sufficient to drive optimal primary expansion, effector and memory differentiation, and metabolic function. In contrast, autocrine IL-2 is uniquely required during primary expansion to program robust secondary expansion potential in memory-fated cells. This study further shows that IL-2 production by antigen-specific CD8 T cells is largely independent of CD4 licensing of dendritic cells (DCs) in inflammatory infections with robust DC activation. These findings bear implications for immunizations and adoptive T cell immunotherapies, where effector and memory functions may be commandeered through IL-2 programming.

All-Trans Retinoic Acid Modulates TLR4/NF-κB Signaling Pathway Targeting TNF-α and Nitric Oxide Synthase 2 Expression in Colonic Mucosa during Ulcerative Colitis and Colitis Associated Cancer.

Colitis associated cancer (CAC) is the colorectal cancer (CRC) subtype that is associated with bowel disease such as ulcerative colitis (UC). The data on role of NF-κB signaling in development and progression of CAC were derived from preclinical studies, whereas data from human are rare. The aim of this work was to study the contribution of NF-κB pathway during UC and CAC, as well as the immunomodulatory effect of all-trans retinoic acid (AtRA). We analyzed the expression of NOS2, TNF-α, TLR4, and NF-κB, in colonic mucosa. We also studied NO/TNF-α modulation by LPS in colonic mucosa pretreated with AtRA. A marked increase in TLR4, NF-κB, TNF-α, and NOS2 expression was reported in colonic mucosa. The relationship between LPS/TLR4 and TNF-α/NO production, as well as the role of NF-κB signaling, was confirmed by ex vivo experiments and the role of LPS/TLR4 in NOS2/TNF-α induction through NF-κB pathway was suggested. AtRA downregulates NOS2 and TNF-α expression. Collectively, our study indicates that AtRA modulates in situ LPS/TLR4/NF-κB signaling pathway targeting NOS2 and TNF-α expression. Therefore, we suggest that AtRA has a potential value in new strategies to improve the current therapy, as well as in the clinical prevention of CAC development and progression.

Overview of cytokines and nitric oxide involvement in immuno-pathogenesis of inflammatory bowel diseases.

Inflammatory bowel diseases (IBDs), including Crohn's disease and ulcerative colitis are complex disorders with undetermined etiology. Several hypotheses suggest that IBDs result from an abnormal immune response against endogenous flora and luminal antigens in genetically susceptible individuals. The dysfunction of the mucosal immune response is implicated in the pathogenesis of IBD. The balance between pro-inflammatory cytokines [tumor necrosis factor (TNF)-α, interleukin (IL)-1ß, IL-8, and IL-17A], anti-inflammatory cytokines (IL-4 and IL-13), and immunoregulatory cytokines (IL-10 and transforming growth factors ß) is disturbed. Moreover, evidence from animal and clinical studies demonstrate a positive correlation between an increased concentration of nitric oxide (NO) and the severity of the disease. Interestingly, proinflammatory cytokines are involved in the up-regulation of inducible oxide synthase (iNOS) expression in IBD. However, anti-inflammatory and immunoregulatory cytokines are responsible for the negative regulation of iNOS. A positive correlation between NO production and increased pro-inflammatory cytokine levels (TNF-α, IL-6, IL-17, IL-12, and interferon-γ) were reported in patients with IBD. This review focuses on the role of cytokines in intestinal inflammation and their relationship with NO in IBD.

A case for IL-6, IL-17A, and nitric oxide in the pathophysiology of Sjögren's syndrome.

Sjögren's syndrome (SS) is an autoimmune epithelitis characterized by mononuclear cell (MNC) infiltration of the lacrimal and salivary glands (SG), as well as the presence of serum autoantibodies. This condition is a growing public health concern in Algeria. Herein, we sought to determine if the levels of interleukin (IL)-6, IL-17A, and nitric oxide (NO), were correlated with the extent of MNC infiltration. The expression of inducible NO synthase (NOS2) and CD68 was measured in the SG of all patients, but not in those of the normal controls (NCs). We included 44 primary Sjögren's syndrome (pSS) patients and 15 NCs in this study; we found that the expression of NOS2 and CD68 was elevated in all of the SG of SS patients. Additionally, the serum and saliva levels of IL-6, IL-17A, and NO were higher in the pSS patients, compared with the NCs. Furthermore, the NOS2-induced excess NO was associated with the extent of the MNC infiltration, and thereby with tissue injury. It is also important to note that there were correlations between the levels of IL-6, IL-17A, and NO. Such findings indicate that through the effects of NO, IL-17A participates in the pathophysiology of the disease. With the purpose of improving both the diagnosis and prognosis, IL-6, IL-17A, and NO should be assayed in the serum and saliva of patients suspected of SS.

Crude extract of hydatid laminated layer from Echinococcus granulosus cyst attenuates mucosal intestinal damage and inflammatory responses in Dextran Sulfate Sodium induced colitis in mice.

BACKGROUND: Inflammatory bowel disease is an immunologically mediated disease. Notably, it is less common in countries where there is a greater risk of exposure to helminths. In our study, we examined the modulatory effect of the laminated layer extracted from the cyst wall of a helminth parasite, Echinococcus granulosus, on dextran sulfate sodium (DSS)-induced colitis in mice. METHODS: An acute colitis was induced in BALB/c mice using 2.5% w/v DSS in drinking water. The crude extract of E. granulosus laminated layer was injected intraperitoneally daily, starting 3 days before colitis induction. The Disease Activity Index was monitored daily, colon length and weight were measured and histological scores were evaluated. Nitric oxide (NO) and cytokine levels (interferon γ (IFN-γ), tumor necrosis factor α (TNF-α) and interleukin 10 (IL-10)) were assessed by enzyme-linked immunosorbent assay. In addition, the colonic expression of inducible nitric oxide synthase (iNOS) and nuclear factor-κB (NF-κB) was examined. Statistical analyses were performed by one-way analysis of variance and the survival rate was analyzed by the long rank test. RESULTS: Hydatid laminated layer pretreatment significantly improved the clinical symptoms and histological scores (*** p < 0.01) observed during DSS-induced colitis and maintained mucus production by goblet cells. Furthermore, treatment with hydatid laminated layer caused a significant decrease in NO, IFN-γ (** p < 0.01) and TNF-α production (* p < 0.05) and an increase in IL-10 production. These results were associated with localized downregulation of iNOS and NF-κB expression. CONCLUSIONS: Our results demonstrate the potent anti-inflammatory effects of hydatid laminated layer. Furthermore, preventive treatment with the laminated layer played a beneficial role in maintaining the integrity of the intestinal mucosal barrier against DSS-induced injury.

Beneficial role of the probiotic mixture Ultrabiotique on maintaining the integrity of intestinal mucosal barrier in DSS-induced experimental colitis.

The etiology of inflammatory bowel diseases which include ulcerative colitis (UC) and Crohn disease has not yet been clarified. Several hypotheses suggest a change in composition of gut microflora along with an impaired mucosal barrier that lead to excessive mucosal immunologic responses. Increased production of nitric oxide (NO) contributes greatly to the tissue injury caused by chronic inflammation. Evidence indicates that the mucus layer covering the epithelium is altered during UC and experimental colitis. Our aim in this study was to investigate the potential therapeutic effect of probiotic during DSS-induced colitis by modulating the immune system and colonic mucus production. For that purpose, the probiotic formulation Ultrabiotique(®) (Lactobacillus acidophilus, Bifidobacterium lactis, Lactobacillus plantarum and Bifidobacterium breve) was administered daily for 7 d to mice with colitis. Probiotic supplementation improved clinical symptoms and histological alterations observed during DSS induced colitis. Ultrabiotique(®) treatment down regulated the NO production by peritoneal macrophages of DSS-treated mice and enhanced mucus production in both DSS-treated and healthy mice. In conclusion, the modification of microflora by the Ultrabiotique(®) played a beneficial role in maintaining the integrity of the intestinal mucosal barrier and promoted tissue repair.

IL-23/IL-17A axis correlates with the nitric oxide pathway in inflammatory bowel disease: immunomodulatory effect of retinoic acid.

Inflammatory bowel diseases (IBDs) are chronic inflammatory diseases of the gastrointestinal tract, which are clinically present as 1 of the 2 disorders, Crohn's disease (CD) or ulcerative colitis (UC) (Rogler 2004). The immune dysregulation in the intestine plays a critical role in the pathogenesis of IBD, involving a wide range of molecules, including cytokines. The aim of this work was to study the involvement of T-helper 17 (Th17) subset in the bowel disease pathogenesis by the nitric oxide (NO) pathway in Algerian patients with IBD. We investigated the correlation between the proinflammatory cytokines [(interleukin (IL)-17, IL-23, and IL-6] and NO production in 2 groups of patients. We analyzed the expression of messenger RNAs (mRNAs) encoding Th17 cytokines, cytokine receptors, and NO synthase 2 (NOS2) in plasma of the patients. In the same way, the expression of p-signal transducer and activator of transcription 3 (STAT3) and NOS2 was measured by immunofluorescence and immunohistochemistry. We also studied NO modulation by proinflammatory cytokines (IL-17A, IL-6, tumor necrosis factor α, or IL-1ß) in the presence or absence of all-trans retinoic acid (At RA) in peripheral blood mononuclear cells (PBMCs), monocytes, and in colonic mucosa cultures. Analysis of cytokines, cytokine receptors, and NOS2 transcripts revealed that the levels of mRNA transcripts of the indicated genes are elevated in all IBD groups. Our study shows a significant positive correlation between the NO and IL-17A, IL-23, and IL-6 levels in plasma of the patients with IBD. Interestingly, the correlation is significantly higher in patients with active CD. Our study shows that both p-STAT3 and inducible NOS expression was upregulated in PBMCs and colonic mucosa, especially in patients with active CD. At RA downregulates NO production in the presence of proinflammatory cytokines for the 2 groups of patients. Collectively, our study indicates that the IL-23/IL-17A axis plays a pivotal role in IBD pathogenesis through the NO pathway.

Mucosal intestinal alteration in experimental colitis correlates with nitric oxide production by peritoneal macrophages: effect of probiotics and prebiotics.

Inflammatory bowel disease (IBD) consists mainly of Ulcerative colitis (UC) and Crohn disease (CD). Although its aetiology is still not clearly established, it is thought to be due to overly aggressive immune response to enteric bacteria in genetically predisposed individuals. Manipulating the microbiota using probiotics or prebiotics is considered as a promising field of new therapeutic strategies used to attenuate immune disorders observed during IBD. The production of nitric oxide (NO) seems to be implicated in IBD pathogenesis. In our study, an acute UC was induced in Swiss mice using 3% Dextran Sulfate Sodium (DSS). The preventive effects of "Ultrabiotique®" (a probiotic) and inulin (a prebiotic) on the colitis were investigated. The production of NO was evaluated in the supernatants of peritoneal macrophages (pMφ) cultures. Colonic mucosa histology was subsequently examined. Results showed severe acute UC after administration of DSS. High levels of NO in pMφ cultures were also observed compared to control samples. These findings correlated with a significant destruction of the colonic mucosa. Oral administration of Ultrabiotique® or inulin decreased the severity of DSS-induced colitis. These treatments lead to a decrease in NO levels in pMφ cultures. A considerable reduction of colonic lesions was also noticed. Our findings suggest the involvement of NO in experimental UC pathogenesis. Pre- and pro-biotics, as discussed herein, seem to have an anti-inflammatory effect.