MicroRNA-1 protects the endothelium in acute lung injury
Acute lung injury (ALI) and its most severe form, acute respiratory distress syndrome (ARDS), cause severe endothelial dysfunction in the lung and vascular endothelial growth factor (VEGF) is elevated in ARDS. We have found that the levels of a VEGF-regulated microRNA, microRNA-1 (miR-1) is reduced in the lung endothelium after acute injury. Pulmonary endothelial cell (EC)-specific overexpression of miR-1 protects the lung against cell death and barrier dysfunction in both murine and human models and increases the survival of mice after pneumonia-induced ALI. MiR-1 has an intrinsic protective effect in pulmonary and other types of ECs; it inhibits apoptosis and necroptosis pathways and decreases capillary leak by protecting adherens and tight junctions. Comparative gene expression analysis and RISC recruitment assays identified miR-1 targets in the context of injury, including  phosphodiesterase 5A (PDE5A), angiopoetin-2 (ANGPT2), connector enhancer of kinase suppressor of ras 3 (CNKSR3) and TNF alpha induced protein 2 (TNFAIP2). We validated miR-1-mediated regulation of ANGPT2 in both mouse and human ECs and found that in a 119-patient pneumonia cohort, miR-1 correlated inversely with ANGPT2. These findings illustrate the novel role of miR-1 as a cytoprotective orchestrator of endothelial response to acute injury with prognostic and therapeutic potential. Overall design: mRNA sequencing of HUVEC transfected with microRNA-1 or control RNA after RNA immunoprecipitation with Argonaute-2 protein, 3 replicates per condition