Oxidative stress is a key contributor to the development of dysregulated inflammation in acute lung injury (ALI). A naturally occurring single nucleotide polymorphism in the key extracellular antioxidant enzyme, extracellular superoxide dismutase (EC-SOD), results in an arginine to glycine substitution (R213G) that promotes resolution of inflammation and protection against bleomycin-induced ALI. Previously we found that mice harboring the R213G mutation in EC-SOD exhibit a transcriptomic profile consistent with a striking suppression of inflammatory and immune pathways 7 days postbleomycin. However, the alterations in noncoding regulatory RNAs in wild-type (WT) and R213G EC-SOD lungs have not been examined. Therefore, we used next-generation microRNA (miR) Sequencing of lung tissue to identify dysregulated miRs 7 days after bleomycin in WT and R213G mice. Differential expression analysis identified 92 WT and 235 R213G miRs uniquely dysregulated in their respective genotypes. Subsequent pathway analysis identified that these miRs were predicted to regulate approximately half of the differentially expressed genes previously identified. The gene targets of these altered miRs indicate suppression of immune and inflammatory pathways in the R213G mice versus activation of these pathways in WT mice. Triggering receptor expressed on myeloid cells 1 (TREM1) signaling was identified as the inflammatory pathway with the most striking difference between WT and R213G lungs. miR-486b-3p was identified as the most dysregulated miR predicted to regulate the TREM1 pathway. We validated the increase in TREM1 signaling using miR-486b-3p antagomir transfection. These findings indicate that differential miR regulation is predicted to regulate the inflammatory gene profile, contributing to the protection against ALI in R213G mice.

中文翻译：

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预计由于 R213G 细胞外超氧化物歧化酶变体引起的博莱霉素后 MicroRNA 调节会抑制炎症和免疫途径。

氧化应激是急性肺损伤 (ALI) 中炎症失调发展的关键因素。关键的细胞外抗氧化酶细胞外超氧化物歧化酶 (EC-SOD) 中天然存在的单核苷酸多态性导致精氨酸取代甘氨酸 (R213G)，从而促进炎症消退和防止博莱霉素诱导的 ALI。以前我们发现在 EC-SOD 中携带 R213G 突变的小鼠表现出与博来霉素后 7 天炎症和免疫途径的显着抑制一致的转录组学特征。然而，尚未检查野生型 (WT) 和 R213G EC-SOD 肺中非编码调节 RNA 的变化。所以，我们使用肺组织的下一代 microRNA (miR) 测序来鉴定 WT 和 R213G 小鼠博来霉素后 7 天失调的 miR。差异表达分析确定了 92 个 WT 和 235 个 R213G miRs 在其各自的基因型中独特地失调。随后的通路分析发现，这些 miRs 预计会调节大约一半的先前确定的差异表达基因。这些改变的 miRs 的基因靶标表明 R213G 小鼠中免疫和炎症途径的抑制与 WT 小鼠中这些途径的激活相比。骨髓细胞上表达的触发受体 1 (TREM1) 信号传导被确定为炎症通路，WT 和 R213G 肺之间的差异最为显着。miR-486b-3p 被确定为预测调节 TREM1 通路的最失调的 miR。我们使用 miR-486b-3p antagomir 转染验证了 TREM1 信号传导的增加。这些发现表明，预计差异 miR 调节可调节炎症基因谱，有助于 R213G 小鼠对 ALI 的保护。