Differential microRNA expression of R213G extracellular superoxide dismutase mice in the setting of inflammation resolution and attenuated acute lung injury. Differential microRNA expression of R213G extracellular superoxide dismutase mice in the setting of inflammation resolution and attenuated acute lung injury

Purpose: 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) which promotes resolution of inflammation and protection against bleomycin-induced ALI. Previously we found that mice with the R213G mutation in EC-SOD have an inflammation-resolving transcriptomic profile at 7 days post-bleomycin However, the epigenetic differences between 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 wild-type (WT) and R213G mice. Methods: WT and homozygous R213G EC-SOD (rs1799895) mice received one intratracheal administration of bleomycin in phosphate-buffered saline (PBS) (100 uL at 1 U/mL) or PBS at 8-12 weeks old. Lungs were harvested and frozen. Frozen lungs were homogenized, placed in Qiazol, and RNA was isolated using the miRNeasy Mini Kit (Qiagen). Samples underwent 1x150, directional, single-end sequencing using the Illumina hiSEQ 4000 system. Results: 1424 microRNAs were detected. Up/Down regulated microRNAs were defined as havinga FC > 1.2 and p <0.05. microRNAs "unique" to a genotype were defined as meeting the prevoius criteria in only one strain, or in both with a fold change 1.5x greater in one over the other. This method identified 92 WT and 235 R213G miRs uniquely dysregulated in their respective genotypes. Overall design: Lung microRNA profiles of 11-week-old WT and R213G mice with intratracheal PBS (control) or bleomycin-induced lung injury from Illumina sequencing.