The alarmin interleukin-1α triggers secondary degeneration through reactive astrocytes and endothelium after spinal cord injury

Spinal cord injury (SCI) triggers neuroinflammation, and subsequently secondary degeneration and oligodendrocyte (OL) death. We report that the alarmin interleukin (IL)−1α is produced by damaged microglia after SCI. Intra-cisterna magna injection of IL-1α in mice rapidly induces neutrophil infiltration and OL death throughout the spinal cord, mimicking the injury cascade seen in SCI sites. These effects are abolished through co-treatment with the IL-1R1 antagonist anakinra, as well as in IL-1R1-knockout mice which demonstrate enhanced locomotor recovery after SCI. Conditional restoration of IL-1R1 expression in astrocytes or endothelial cells (ECs), but not in OLs or microglia, restores IL-1α-induced effects, while astrocyte- or EC-specific Il1r1 deletion reduces OL loss. Conditioned medium derived from IL-1α-stimulated astrocytes results in toxicity for OLs; further, IL-1α-stimulated astrocytes generate reactive oxygen species (ROS), and blocking ROS production in IL-1α-treated or SCI mice prevented OL loss. Thus, after SCI, microglia release IL-1α, inducing astrocyte- and EC-mediated OL degeneration

Near-Surface Wind Observation Impact on Forecasts: Temporal Propagation of the Analysis Increment

This study examines the assimilation of near-surface wind observations over land to improve wind nowcasting and short-term tropospheric forecasts. A new geostatistical operator based on geophysical model output statistics (GMOS) is compared with a bilinear interpolation scheme (Bilin). The multivariate impact on forecasts and the temporal evolution of the analysis increments produced are examined as well as the influence of background error covariances on different components of the prediction system. Results show that Bilin significantly degrades surface and upper-air fields when assimilating only wind data from 4942 SYNOP stations. GMOS on the other hand produces smaller increments that are in better agreement with the model state. It leads to better short-term near-surface wind forecasts and does not deteriorate the upper-air forecasts. The information persists longer in the system with GMOS, although the local improvements do not propagate beyond 6-h lead time. Initial model tendencies indicate that the mass field is not significantly altered when using static error covariances and the boundary layer parameterizations damp the poorly balanced increment locally. Conversely, most of the analysis increment is propagated when using flow-dependent error statistics. It results in better balanced wind and mass fields and provides a more persistent impact on the forecasts. Forecast accuracy results from observing system experiments (assimilating SYNOP winds with all observations used operationally) are generally neutral. Nevertheless, forecasts and analyses from GMOS are more self-consistent than those from both Bilin and a control experiment (not assimilating near-surface winds over land) and the information from the observations persists up to 12-h lead time

Implication de la signalisation de l'interleukine-1bêta dans la pathogenèse de l'encéphalomyélite auto-immune expérimentale

Thèse ou mémoire avec insertion d'article

The Montreal-96 Experiment on Regional Mixing and Ozone (MERMOZ): An Overview.

Peer reviewed: YesNRC publication: Ye

An Evaluation of a TKE-Based Boundary Layer Model Using Clear Day Cases from MERMOZ.

Peer reviewed: YesNRC publication: Ye

The Montreal-96 Experiment on Regional Mixing and Ozone (MERMOZ): An Overview and Some Preliminary Results.

The MERMOZ (Montreal-96 Experiment on Regional Mixing and Ozone) field experiment was conducted in the greater Montreal area in June 1996. The measurement program was designed to examine several aspects of boundary layer dynamics and chemical transport. The project featured high-resolution real-time simulations with a mesoscale meteorological model driving several air quality models; the deployment of a research aircraft, fully instrumented for turbulent flux measurements; and a number of other supporting meteorological measurements such as two boundary layer wind profilers, a Doppler weather radar, and a special network of surface stations, upper-air soundings, tethersondes, and ozonesondes. An overview of the MERMOZ field program is presented with some preliminary results on various aspects of the experiment.NRC publication: Ye