New Insights into the Immunological Changes in IL-10-Deficient Mice during the Course of Spontaneous Inflammation in the Gut Mucosa

IL-10 is a regulatory cytokine that plays a major role in the homeostasis of the gut and this is illustrated by the fact that IL-10−/− mice develop spontaneous colitis. In this study, IL-10−/− mice were analyzed for immunological changes during colitis development. We found a reduced frequency of regulatory T cells CD4+CD25+Foxp3+ and higher frequency of activated T cells in the colon that precedes the macroscopic signs of the disease. Production of IL-17 and IFN-γ was higher in the colon. Colitis progression culminates with the reduction of CD4+LAP+ regulatory T cells in the intestine. Frequency of B1 cells and the secretory IgA production were both elevated. Despite these alterations, 16-week-old IL-10−/− mice could be rendered tolerant by a continuous feeding protocol. Our study provides detailed analysis of changes that precede colitis and it also suggests that oral tolerance could be used to design novel alternative therapies for the disease

Efeitos imuno-moduladores do Ácido Linoléico Conjugado (CLA) na colite e no adenocarcinoma de cólon murino

Exportado OPUSMade available in DSpace on 2019-08-13T04:08:56Z (GMT). No. of bitstreams: 1 tese_thais_g_moreira.pdf: 4809893 bytes, checksum: c2aa3419b2143459cc687435502ffc9a (MD5) Previous issue date: 31O tecido linfóide associado à mucosa intestinal está separado do lúmen do intestino por uma única camada de celulas epiteliais e convive em uma relação equilibrada com os vários components da dieta. Vitaminas, Carboidratos, Proteínas e Lipídeos são reconhecidos por diferentes celulas do sistema imune e, por isso, além do seu papel nutritivo, desempenham função antigênica importante. As diferentes formas lipídicas presentes nos alimentos podem afetar o sistema imune diretamente através da modulação gênica. Neste trabalho, estudamos os efeitos imunológicos do Ácido Linoléico Conjugado (CLA), um isômero posicional e geomêtrico do Ácido Linoléico, capaz de ativar o fator de transcrição proliferador de peroxissoma PPAR- e de realizar várias funções no organismo. Devido à suas propriedades anti-carcinogênica e anti-inflamatória já descritas, o CLA foi testado, neste trabalho, como agente modulador da Doença Inflamatória Intestinai (DIIs) (colite ulcerativa) que está fortemente relacionadaao desenvolvimento do câncer de cólon. Constatamos que a suplementação dietética com CLA foi capaz de prevenir a Doença Inflamatória Intestinal, diminuindo o dano na mucosa e o infiltrado inflamatório em um modelo experimental de colite induzida por Sulfato de Sódio Dextrano (DSS). Macrófagos com perfil M2 (anti-inflamatório) participaram desse efeito. Por outro lado, camundongos LysMCre PPARflox/flox , seletivamente deficientes em PPAR- nas células mielóides, suplementados com dieta CLA não foram protegidos dacolite. Assim, os efeitos do CLA sobre a colite são dependentes de PPAR-. Utilizando o modelo de colite por DSS, observamos ainda que a esteatose hepática causada pela suplementação de CLA no estado naïve é revertida nos animais com colite devido às alterações metabólicas causadas pela doença inflamatória, o que viabiliza a utilização do CLA como terapia alternativa na DII. Apesar de eficiente na prevenção da colite, a suplementação de CLA piorou significativamente os processos tumorais encontrados em modelo de adenocarcinoma induzido por DSS e Azoximetano. Esse efeito foi acompanhadoda geração de células T reguladoras LAP+ (expressando TGF- de membrana) e de macrófagos produtores de TGF- na lâmina própria do intestino de camundongos suplementados com dieta contendo CLA. Mostramos, em sistema in vitro utilizando agonistas de PPAR-, que a indução de TGF- em linfócitos e macrófagos é dependente de PPAR-. A neutralização do efeito pro-tumoral do CLA pela administração in vivo de anticorpos anti-TGF- e a utilização de camundongos deficientes em PPAR- nas células mielóides mostra a importância da citocina TGF- e do fator de trasncrição do PPAR- no efeito protumoral do CLA. Concluímos, portanto, que as propriedades anti-inflamatórias doCLA se associam à prevenção da colite induzida por DSS, mas contribuem para o desenvolvimento de adenocarcinoma de cólon.The lymphoid tissue associated with the intestinal mucosa is separated from the gut lumen by a single layer of epithelial cells and coexists adjusted in a relationship with the different components of dietary food. Vitamins, Carbohydrates, Proteins and Lipids are recognized by different immune cells. Therefore, these dietary components play an important antigenic function beyond their nutritional role. Different lipid forms present in food can affect the immune system directly through modulation of gene expression. In this work, we studied the immunological effects of Conjugated Linoleic Acid (CLA), the geometric and positional isomerof Linoleic acid that activates the transcriptional factor peroxime proliferator PPAR- and modulates several functions of the body. Due to its already described anti-carcinogenic and anti-inflammatory effects, CLA was chosen as modulating agent of Inflammatory Bowel Diseases (DII) that are strongly correlated with the development of colon cancer. We demonstrated that dietary supplementation with CLA was able to prevent DII, reducing the mucosal damage and inflammatory infiltrates in an experimental model of colitis induced by dextran sodium sulfate (DSS). Macrophages with M2 profile (antiinflammatory) were players in this effect. In the other hand, LysMCre PPARflox/flox mice PPAR- deficient in myeloid cells supplemented with CLA diet was not protected from colitis. Thus, the CLA effect over the colitis is PPAR- dependent. By using the DSS model, we also observed that the steatosis process in CLA-supplementated naïve mice is reverted on colitis due the metabolic alteration caused by the inflammatory disease, that enables the CLA use as therapeutic tool on DII. Although effective in preventing DSS-induced colitis, CLA supplementation significantly worsened the tumor processes found in colorectal cancer (CRC) induced by a combination of DSS and azoxymethane. This effect was associated with the generation of CD4+LAP+ regulatory T cells (membrane-bound TGF-) and TGF- producer macrophages in the gut lamina propria of CLA-suplemmented mice. We showed, in vitro, by using the PPAR- agonist, that the TGF- induction on lymphocytes and macrophages is PPAR- dependent. Neutralization of the pro-tumor effect of CLA by in vivo administration of anti-TGF- antibodies and the use of LysMCre PPARflox/flox mice show the role of the cytokine TGF- ans the transcriptional factor PPAR- over CLA protumoral effect. We conclude, therefore, the anti-inflammatory properties of CLA are positively associated with prevention of DSS-induced colitis but also with development of colon tumors

Food components and the Immune System: from tonic agents to allergens

The intestinal mucosa is the major site of contact with antigens, and it lodges the largest lymphoid tissue in the body. In physiological conditions, microbiota and dietary antigens are the natural sources of stimulation for the gut associated lymphoid tissues (GALT) and for the immune system as a whole. Germ free models have provided some insights on the immunological role of gut antigens. However, most of the GALT is not located in the large intestine, where gut microbiota is prominent. It is concentrated in the small intestine where protein absorption takes place. In this review, we will address the involvement of food components in the development and the function of the immune system. Studies in mice have already shown that dietary proteins are critical elements for the developmental shift of the immature neonatal immune profile into a fully developed immune system. The immunological effects of other food components (such as vitamins and lipids) will also be addressed. Most of the cells in the GALT are activated and local proinflammatory mediators are abundant. Regulatory elements are known to provide a delicate yet robust balance that keeps the gut homeostasis at check. Usually antigenic contact in the gut induces two major immune responses, oral tolerance and production of secretory IgA. However, under pathological conditions mucosal homeostasis is disturbed resulting in inflammatory reactions such as food hypersensitivity. Food allergy development depends on many factors such as genetic predisposition, biochemical features of allergens and a growing array of environmental elements. Neuroimmune interactions are also implicated in food allergy and they are examples of the high complexity of the phenomenon. Recent findings on the gut circuits triggered by food components will be reviewed to show that, far beyond their role as nutrients, they are critical players in the operation of immune system in health and disease

New Insights into the Immunological Changes in IL-10-Deficient Mice during the Course of Spontaneous Inflammation in the Gut Mucosa

IL-10 is a regulatory cytokine that plays a major role in the homeostasis of the gut and this is illustrated by the fact that IL-10−/− mice develop spontaneous colitis. In this study, IL-10−/− mice were analyzed for immunological changes during colitis development. We found a reduced frequency of regulatory T cells and higher frequency of activated T cells in the colon that precedes the macroscopic signs of the disease. Production of IL-17 and IFN-γ was higher in the colon. Colitis progression culminates with the reduction of regulatory T cells in the intestine. Frequency of B1 cells and the secretory IgA production were both elevated. Despite these alterations, 16-week-old IL-10−/− mice could be rendered tolerant by a continuous feeding protocol. Our study provides detailed analysis of changes that precede colitis and it also suggests that oral tolerance could be used to design novel alternative therapies for the disease.Peer Reviewe

Local and Systemic Immune Mechanisms Underlying the Anti-Colitis Effects of the Dairy Bacterium Lactobacillus delbrueckii.

Several probiotic bacteria have been proposed for treatment or prevention of inflammatory bowel diseases (IBD), showing a protective effect in animal models of experimental colitis and for some of them also in human clinical trials. While most of these probiotic bacteria are isolated from the digestive tract, we recently reported that a Lactobacillus strain isolated from cheese, L. delbrueckii subsp. lactis CNRZ327 (Lb CNRZ327), also possesses anti-inflammatory effects in vitro and in vivo, demonstrating that common dairy bacteria may be useful in the treatment or prevention of IBD. Here, we studied the mechanisms underlying the protective effects of Lb CNRZ327 in vivo, in a mouse dextran sodium sulfate (DSS) colitis model. During colitis, Lb CNRZ327 modulated the production of TGF-β, IL-6, and IL-12 in colonic tissue and of TGF-β and IL-6 in the spleen, and caused an expansion of CD4+Foxp3+ regulatory T cells in the cecal lymph nodes. Moreover, a strong tendency to CD4+Foxp3+ expansion was also observed in the spleen. The results of this study for the first time show that orally administered dairy lactobacilli can not only modulate mucosal but also systemic immune responses and constitute an effective treatment of IBD

Anti-inflammatory effects of Lactococcus lactis NCDO 2118 during the remission period of chemically-induced colitis

Many probiotic bacteria have been described as a promising tool in the therapy of Inflammatory Bowel Diseases (IBD). Most of them belong to the Lactic Acid Bacteria (LAB) group, which makes part of our healthy microbiota. However, little is known about the effects of transiting dairy bacteria that make part of our diet, including Lactococcus lactis. In the present study, we analyzed the immune modulation effects of three L. lactis strains in vitro using intestinal epithelial cells and the effectiveness of a selected strain in a murine model of colitis. Only one strain, L. lactis NCDO 2118, was able to reduce the IL1-β-induced IL-8 secretion in Caco-2 cells, suggesting a potential anti-inflammatory effect of this strain. In vivo, L. lactis NCDO 2118 was administered for 4 days to C57BL/6 mice during a remission period between a first and second course of colitis induced by dextran sulfate sodium. This resulted in a milder form of recurrent colitis than observed in mice administered medium during this same period. This protective effect was not attributable to changes in secretory IgA, however NCDO 2118 administration was associated with early increase in IL-6 production and by the maintenance of IL-10 in colonic tissue. Mice fed with L. lactis NCDO 2118 increased the number of regulatory CD4+ T cells bearing surface TGF-β in the form of latency-associated protein in mesenteric lymph node and spleen. The results of this study allowed us to identify a new probiotic strain that may be used in the treatment of IBD as well as some of the mechanism involved in its anti-inflammatory effect. Fil: Diniz Luerce, Tessália. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Biologia Geral; BrasilFil: Gomes Santos, Ana Cristina. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Bioquímica e Imunologia; BrasilFil: Santos Rochat, Clarissa. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Biologia Geral; BrasilFil: Garcias Moreira, Thais. Universidade Federal de Minas Gerais. Faculdade de Farmácia. Departamento de Ciência de Alimentos.; BrasilFil: Nogueira Cruz, Déborah. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Bioquímica e Imunologia; BrasilFil: Lemos, Luísa. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Bioquímica e Imunologia; BrasilFil: Sousa, Adna Luciana. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Bioquímica e Imunologia; BrasilFil: Bastos Pereira, Vanessa. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Biologia Geral; BrasilFil: de Azevedo, Marcela. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Biologia Geral; BrasilFil: Moraes, Kátia. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Biologia Geral; BrasilFil: Carmona Cara, Denise. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Morfologia; BrasilFil: Leblanc, Jean Guy Joseph. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Tucumán. Centro de Referencia para Lactobacilos (i); ArgentinaFil: Azevedo, Vasco. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Biologia Geral; BrasilFil: Caetano Faria, Ana Maria. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Bioquímica e Imunologia; BrasilFil: Miyoshi, Anderson. Universidade Federal de Minas Gerais. Instituto de Ciências Biológicas. Departamento de Biologia Geral; Brasi

CLA-supplemented diet accelerates experimental colorectal cancer by inducing TGF-β-producing macrophages and T cells

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Colon histology after DSS-induced colitis.

<p><b>A</b>. Descending colon of the negative control group (without bacteria or DSS). <b>B</b>. Descending colon of the positive group control (only DSS). <b>C</b>. Descending colon of the experimental group (DSS plus Lb CNRZ327). A, B, and C each show representative results from three independent experiments. <b>D</b>. Histological score of the groups described above. Bars represent the mean ± SEM calculated across three independent experiments, with 4 or 5 mice per group in each experiment (combined sample sizes: 13 to 14 mice per treatment). *** = p<0.001.</p