MicroRNA-145 plays a role in mitochondrial dysfunction in alveolar epithelial cells in lipopolysaccharide-induced acute respiratory distress syndrome

BACKGROUND: Acute respiratory distress syndrome (ARDS) causes substantial mortalities.Alveolar epithelium is one of the main sites of cell injuries in ARDS. As an important kind of microRNAs(miRNAs), microRNA-145 (miR-145) has been studied in various diseases, while its role in ARDS has notbeen investigated.METHODS: Lipopolysaccharide (LPS) was intratracheally instilled to establish a rat ARDS model.Cytokines from bronchoalveolar lavage fl uid (BALF) were measured using rat tumor necrosis factor-α andinterleukin-6 enzyme-linked immunosorbent assay kits (R&D Systems), and the pathological structureswere evaluated using hematoxylin and eosin (H&E) staining and transmission electron microscope;thelung miR-145 messenger RNA (mRNA) was detected using quantitative polymerase chain reaction.Bioinformatics focused on the target genes and possible pathways of gene regulation.RESULTS: A rat model of LPS-induced ARDS was successfully established. The miR-145was down-regulated in the LPS-induced ARDS lung, and mitochondrial dysfunction was observedin alveolar epithelial cells, most obviously at 72 hours after LPS. TargetScan and miRDB databaseswere used to predict the target genes of miR-145. A total of 428 overlapping genes were identifi ed,seven genes were associated with mitochondrial function, and Ogt, Camk2d, Slc8a3, and Slc25a25were verifi ed. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were enriched in themitogen-activated protein kinase (MAPK) signaling pathway, and Gene Ontology (GO) biologicalprocess was mainly enriched in signal transduction and transcription regulation.CONCLUSIONS: The miR-145 is down-regulated in LPS-induced ARDS, and affects itsdownstream genes targeting mitochondrial functions.

Vertical grain-size trend of mouth bar in lacustrine fan delta:Flume experiments

Field observational previously indicated a mouth bar of a fan delta could exhibit a fining-or coarseningupward trend,which bring a new challenge to the identification of mouth bar in subsurface studies due to the lack of morphological descriptions.Previous studies have indicated that effluent behavior in rivermouth system can affect the vertical grain-size trend of mouth bar,but the drivers and magnitude of this phenomenon are not understood.We conducted flume experiments to investigate the mechanism and controlling factors of vertical grain-size trend of mouth bar.Experiment with a steeper slope of the substrate layer,greater discharge,higher sediment/water ratio,and coarser sediment induced a finingupward trend of mouth bar,because the effluent was dominated by strong inertia.Mouth bar in the experiment with a gentler slope of the substrate layer,smaller discharge,lower sediment/water ratio,and finer sediment exhibited a coarsening-upward trend dominated by the friction-dominated effluent.The relationship between the vertical grain-size trend of mouth bar and the gradients of foreset bedding in small-scale flume models and the cut-off of 15°-18°are applicable in natural systems.Identifying depositional setting to infer depositional process in river-mouth system and analyzing the plane geometry of sandbodies are two steps in the interpretation of ancient fan deltaic rock record.