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Sepsis-induced acute lung injury (ALI) is associated with dysregulated inflammatory reactions. MiR-19b-3p level was reported to be downregulated in patients with sepsis. In order to evaluate the role of miR-19b-3p in sepsis, cecum ligation and puncture (CLP)-induced mouse sepsis model and lpopolysaccharide (LPS)-treated pulmonary microvascular endothelial cells (PMVECs) were used. For in vivo study, lung tissue was harvested for hematoxylin and eosin (H&E) staining, TNF-α, IL-6, IL-1β and p-p65, p-IκB measuring. Cell apoptosis was assessed by TUNEL assay. For in vitro study, cell proliferation and apoptosis were detected by CCK-8 and flow cytometry, respectively. Methylation of miR-19b-3p promoter was measured by methylation-specific PCR (MSP) assay. The target of miR-19b-3p was determined by dual-luciferase reporter gene assay. The level of miR-19b-3p was determined to be downregulated in vitro and in vivo. In addition, miR-19b-3p protected mice from inflammation injury through inhibiting NF-κB signaling pathway. Overexpression of miR-19b-3p increased cell viability, decreased apoptosis and pro-inflammatory cytokines secretion in LPS-treated PMVECs. Besides these, KLF7 was confirmed as the target of miR-19b-3p. And methylation of miR-19b-3p was the reason of decreased miR-19b-3p level. In conclusion, miR-19b-3p protected cells from sepsis-induced inflammation injury via inhibiting NF-κB signaling pathway, and KLF7 was a potential target. This article is protected by copyright. All rights reserved.

The aim of this study was to explore the value of the combination between lung ultrasound score (LUS) and the expression of plasma miR-21-3p in predicting the prognosis of patients with acute lung injury (ALI).A total of 136 ALI patients were divided into survival (n = 86) and death groups (n = 50), or into low/middle-risk (n = 77) and high-risk groups (n = 59) according to APACHE II scores. Bioinformatics was used to explore the mechanism of action of miR-21-3p in humans. Real-time fluorescent quantitative PCR was used to detect the expression of miR-21-3p in plasma, and LUS was recorded. Receiver operator characteristic (ROC) curve and Pearson correlation were also used.The LUS and expression level of plasma miR-21-3p in the death and high-risk groups were significantly higher than those in the survival and low/middle-risk groups (p 0.01 and p 0.05). miR-21-3p expression leads to pulmonary fibrosis and promotes the deterioration of ALI patients by regulating fibroblast growth factor and other target genes. ROC curve analysis showed that the best cutoff values for LUS and plasma miR-21-3p expression were 18.60 points and 1.75, respectively. LUS score and miR-21-3p combined predicted the death of ALI patients with the largest area under the curve (0.907, 95% CI: 0.850-0.964), with sensitivity and specificity of 91.6% and 85.2%, respectively. The expression level of plasma miR-21-3p was positively correlated with LUS in the death group (r = 0.827, p 0.01).LUS and expression level of miR-21-3p in plasma are correlated with the severity and prognosis of ALI patients, and their combination has a high value for the prognostic assessment of ALI patients.