Involvement of microRNAs in the cytotoxic effects exerted by proinflammatory cytokines on pancreatic beta-cells.

OBJECTIVE: Pancreatic beta-cells exposed to proinflammatory cytokines display alterations in gene expression resulting in defective insulin secretion and apoptosis. MicroRNAs are small noncoding RNAs emerging as key regulators of gene expression. Here, we evaluated the contribution of microRNAs to cytokine-mediated beta-cell cytotoxicity. RESEARCH DESIGN AND METHODS: We used global microarray profiling and real-time PCR analysis to detect changes in microRNA expression in beta-cells exposed to cytokines and in islets of pre-diabetic NOD mice. We assessed the involvement of the microRNAs affected in cytokine-mediated beta-cell failure by modifying their expression in insulin-secreting MIN6 cells. RESULTS: We found that IL-1beta and TNF-alpha induce the expression of miR-21, miR-34a, and miR-146a both in MIN6 cells and human pancreatic islets. We further show an increase of these microRNAs in islets of NOD mice during development of pre-diabetic insulitis. Blocking miR-21, miR-34a, or miR-146a function using antisense molecules did not restore insulin-promoter activity but prevented the reduction in glucose-induced insulin secretion observed upon IL-1beta exposure. Moreover, anti-miR-34a and anti-miR-146a treatment protected MIN6 cells from cytokine-triggered cell death. CONCLUSIONS: Our data identify miR-21, miR-34a, and miR-146a as novel players in beta-cell failure elicited in vitro and in vivo by proinflammatory cytokines, notably during the development of peri-insulitis that precedes overt diabetes in NOD mice.

Decision criteria for optimizing postemergence johnsongrass control in soybean crops in Argentina

Field studies were established in Zavalla and Oliveros, Argentina, during four years in order to optimize Johnsongrass (Sorghum halepense (L.) Pers.) chemical control by means of the thermal calendar model in comparison with other criteria (weed height or days after sowing). The effect of three application dates of postemergence herbicides was determined by visual control, density of tillers originated from rhizome bud regrowth, and from crown and shoot bud regrowth, and soybean yield. Following the thermal calendar model criterion, applications during the second date afforded the best control. Weed height for the first date showed little variability between experiments but was highly variable in the second and third application dates, achieving in some cases values greater than 120 cm. For all years, no significant differences were detected for crop yield between the first and second application dates, and yields were always lower for the third date. The greatest rhizome bud regrowth was observed for the earliest application date and the highest crown and shoot bud regrowth was determined for the last application date. Parameters associated with control efficiency showed the best behaviour for the second date. However, plant height at this moment may interfere with herbicide application and the variability exhibited by this parameter highlights the risk of determining control timing using only one decision criterion.

Citizen participation and the Lisbon Treaty : A legal perspective

How to "bring the [European] Union closer to its citizens" is a vexed and vital problem of European integration. Article 11 TEU on participatory democracy, recently introduced by the Lisbon Treaty, is meant to be part of the solution. The EU Economic and Social Committee has gone so far as to define this provision "a milestone on the road to a people's Europe that is real and feasible". This appears to be an overly optimistic assessment - partly because art. 11 relies heavily on the involvement of civil society organisations, which political science literature suggests is conceptually and/or practically irrelevant to citizen involvement; partly because it largely formalizes participatory practices that have been in existence for years without cognizable effects on citizen participation; and partly because even its most innovative element - the European citizens' initiative (ECI) - does not bring significant changes to the Union's constitutional arrangements in terms of redistributing decision-making power. In addition to that, secondary legislation places significant hurdles on the submission of ECIs and might prevent or delay their becoming a standard democratic practice. This is not to say that art. 11 TEU has no potential at all. Its insertion in the Treaty might provide impetus to rethink and develop past participatory practices, such as horizontal civil dialogue. Moreover, the effects of "popular input" in the form of ECIs on EU institutional dynamics is as yet unknown - and perhaps not negligible, to judge from the keen interest that the European Parliament and other bodies have demonstrated in "appropriating" it as a political asset. Finally, art. 11 raises the stakes of the Union's democratic challenge and might pressure EU institutions to make full use of its potential. Or, if eventually proved inadequate, art. 11 might constitute a constitutional experiment on the way to meaningful forms of direct democracy at EU level.

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