TNF-α induced endothelial MAdCAM-1 expression is regulated by exogenous, not endogenous nitric oxide

BACKGROUND: MAdCAM-1 is an adhesion molecule expressed in Peyer's patches and lymphoid tissues which is mobilized by cytokines like TNF-α and is a major determinant of lymphocyte trafficking to the gut in human inflammatory bowel disease (IBD). It has been suggested that both reactive oxygen and nitrogen metabolites participate in regulating adhesion molecule expression in response to TNF-α. METHODS: To examine how exogenous and endogenous sources of NO modulate MAdCAM-1 induction by TNF-α, we pre-treated mouse lymphatic endothelial cells with either long or short acting NO donors prior to TNF-α-stimulation, and measured MAdCAM-1 induction at 24 h. RESULTS AND DISCUSSION: DETA-NO, a long-acting NO donor, and SperNO, a rapid releasing NO donor both inhibited TNF-α-stimulated MAdCAM-1 expression in a concentration dependent manner. Both NO donors also reduced a4b7-dependent lymphocyte endothelial adhesion. Inhibition of endogenous NO production by either L-NAME, a non-selective NOS inhibitor, or by 1400 w, a selective iNOS inhibitor failed to induce, or potentiate TNF-α regulated MAdCAM-1 expression. CONCLUSIONS: Exogenous NO donors may be beneficial in the treatment of IBD, while endogenous nitric oxide synthases may be less effective in controlling adhesion molecule expression in response to cytokines

Modeling the vacuolar storage of malate shed lights on pre- and post-harvest fruit acidity

Background: Malate is one of the most important organic acids in many fruits and its concentration plays a critical role in organoleptic properties. Several studies suggest that malate accumulation in fruit cells is controlled at the level of vacuolar storage. However, the regulation of vacuolar malate storage throughout fruit development, and the origins of the phenotypic variability of the malate concentration within fruit species remain to be clarified. In the present study, we adapted the mechanistic model of vacuolar storage proposed by Lobit et al. in order to study the accumulation of malate in pre and postharvest fruits. The main adaptation concerned the variation of the free energy of ATP hydrolysis during fruit development. Banana fruit was taken as a reference because it has the particularity of having separate growth and post-harvest ripening stages, during which malate concentration undergoes substantial changes. Moreover, the concentration of malate in banana pulp varies greatly among cultivars which make possible to use the model as a tool to analyze the genotypic variability. The model was calibrated and validated using data sets from three cultivars with contrasting malate accumulation, grown under different fruit loads and potassium supplies, and harvested at different stages. Results: The model predicted the pre and post-harvest dynamics of malate concentration with fairly good accuracy for the three cultivars (mean RRMSE = 0.25-0.42). The sensitivity of the model to parameters and input variables was analyzed. According to the model, vacuolar composition, in particular potassium and organic acid concentrations, had an important effect on malate accumulation. The model suggested that rising temperatures depressed malate accumulation. The model also helped distinguish differences in malate concentration among the three cultivars and between the pre and post-harvest stages by highlighting the probable importance of proton pump activity and particularly of the free energy of ATP hydrolysis and vacuolar pH. Conclusions: This model appears to be an interesting tool to study malate accumulation in pre and postharvest fruits and to get insights into the ecophysiological determinants of fruit acidity, and thus may be useful for fruit quality improvement. (Résumé d'auteur

Insights into the Molecular Mechanisms of the Anti-Atherogenic Actions of Flavonoids in Normal and Obese Mice

Obesity is a major and independent risk factor for cardiovascular disease and it is strongly associated with the development of dyslipidemia, insulin resistance and type 2 diabetes. Flavonoids, a diverse group of polyphenol compounds of plant origin widely distributed in human diet, have been reported to have numerous health benefits, although the mechanisms underlying these effects have remained obscure. We analyzed the effects of chronic dietary supplementation with flavonoids extracted from cranberry (FLS) in normal and obese C57/BL6 mice compared to mice maintained on the same diets lacking FLS. Obese mice supplemented with flavonoids showed an amelioration of insulin resistance and plasma lipid profile, and a reduction of visceral fat mass. We provide evidence that the adiponectin-AMPK pathway is the main mediator of the improvement of these metabolic disorders. In contrast, the reduced plasma atherogenic cholesterol observed in normal mice under FLS seems to be due to a downregulation of the hepatic cholesterol synthesis pathway. Overall, we demonstrate for the first time that the molecular mechanisms underlying the beneficial effects of flavonoids are determined by the metabolic state

Estrogen mediated-activation of miR-191/425 cluster modulates tumorigenicity of breast cancer cells depending on estrogen receptor status.

MicroRNAs (miRNAs), single-stranded non-coding RNAs, influence myriad biological processes that can contribute to cancer. Although tumor-suppressive and oncogenic functions have been characterized for some miRNAs, the majority of microRNAs have not been investigated for their ability to promote and modulate tumorigenesis. Here, we established that the miR-191/425 cluster is transcriptionally dependent on the host gene, DALRD3, and that the hormone 17β-estradiol (estrogen or E2) controls expression of both miR-191/425 and DALRD3. MiR-191/425 locus characterization revealed that the recruitment of estrogen receptor α (ERα) to the regulatory region of the miR-191/425-DALRD3 unit resulted in the accumulation of miR-191 and miR-425 and subsequent decrease in DALRD3 expression levels. We demonstrated that miR-191 protects ERα positive breast cancer cells from hormone starvation-induced apoptosis through the suppression of tumor-suppressor EGR1. Furthermore, enforced expression of the miR-191/425 cluster in aggressive breast cancer cells altered global gene expression profiles and enabled us to identify important tumor promoting genes, including SATB1, CCND2, and FSCN1, as targets of miR-191 and miR-425. Finally, in vitro and in vivo experiments demonstrated that miR-191 and miR-425 reduced proliferation, impaired tumorigenesis and metastasis, and increased expression of epithelial markers in aggressive breast cancer cells. Our data provide compelling evidence for the transcriptional regulation of the miR-191/425 cluster and for its context-specific biological determinants in breast cancers. Importantly, we demonstrated that the miR-191/425 cluster, by reducing the expression of an extensive network of genes, has a fundamental impact on cancer initiation and progression of breast cancer cells

Isolation and Purity Assessment of Membranes from Norway Spruce

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Calagem e adubação fosfatada promovem crescimento inicial e produção de hipericina em erva-de-São-João Liming and phosphate fertilization promote initial growth and hipericin production in St. John's wort

A erva-de-São-João é uma planta medicinal empregada no tratamento antidepressivo. A hipericina é considerada um dos compostos que contribui para o efeito medicinal da planta. Uma vez que a concentração e a quantidade do princípio ativo pode ser afetada pela nutrição das plantas, este trabalho teve por objetivo avaliar os efeitos do pH do solo e da adubação fosfatada sobre o crescimento inicial e a produção de hipericina em erva-de-São-João. O experimento foi realizado em Lages, SC, de julho a dezembro de 2003, em casa de vegetação. Utilizou-se delineamento experimental inteiramente casualizado (fatorial 4 x 3), correspondendo a quatro valores de pH (4,1; 5,5; 6,0 e 6,5) e três doses de P (0, 50 e 100 mg kg-1 de solo), com quatro repetições. Foram cultivadas duas plantas por vaso, em um Cambissolo Húmico Álico. Avaliou-se a produção de massa seca, a altura e o número de ramificações da parte aérea, o número de glândulas escuras nas folhas e a concentração e a quantidade total de hipericina na parte aérea. A produção de massa seca da parte aérea aumentou com a adição de P e, em maior magnitude, com a calagem. A altura das plantas somente foi influenciada pela calagem. O número de ramificações e de glândulas escuras e a concentração de hipericina aumentaram com a aplicação de P apenas na ausência de calagem, e com a calagem na ausência de P. Os maiores conteúdos de hipericina por vaso foram verificados nos tratamentos com pH 6,0 e 6,5 e doses de P de 50 e 100 mg kg-1 de solo.<br>St. Jonh's wort is a medicinal plant used for anti-depressive treatment. Hypericin is considered one of the compounds that contribute to the medicinal effect of the plant. Since the concentration and the total quantity of active ingredients may be affected by plant nutrition, this work was conducted to investigate the effects of soil pH and phosphorus (P) addition to the soil on initial growth and hypericin production of St. John's wort. The experiment was carried out in Lages, SC, from July until December of 2003, in a greenhouse. It followed a completely randomized factorial design (4 x 3), with four levels of pH (4.1, 5.5, 6.0, and 6.5) and three doses of P (0, 50, and 100 mg kg-1 of soil), and four replicates. Two plants were cultivated per pot, under a Humic Inceptisol. Plants were harvested and assessed for aerial dry matter production, height, number of lateral shoots, number of dark glands in the leaves, aerial hypericin content and aerial total hypericin production. The aerial dry matter production increased with P addition and, in a larger amount, with liming. The plant height was only affected by the liming. The number of lateral shoots and dark glands in the leaves as well as the hipericin concentration only increased with P application in the soil without liming, and with liming in the soil that did not receive P. The highest total hypericin production per pot was achieved in the treatments with pH values of 6.0 and 6.5 and P doses of 50 and 100 mg kg-1 of soil