miRNA-149-5p protects endothelial function and attenuates sepsis-induced acute lung injury by targeting ABCA1.

Abstract

BACKGROUND: Sepsis-induced acute lung injury (ALI) remains a leading cause of mortality in critically ill patients, characterized by endothelial barrier dysfunction and uncontrolled inflammation. While microRNAs regulate endothelial responses during sepsis, the role of miR-149-5p remains unclear. METHODS: We conducted RNA-seq analysis to screen miR-149-5p expression in lipopolysaccharide (LPS)-stimulated endothelial cells, followed by functional validation via in vitro modulation of miR-149-5p with assessment of junction proteins (ZO-1, occludin, VE-cadherin) and adhesion molecules (ICAM1), as well as in vivo studies using a cecal ligation and puncture (CLP) mouse model treated with agomiR-149-5p. Mechanistic studies included bioinformatics predictions, dual-luciferase reporter assays to verify targets, and ABCA1 knockdown/overexpression rescue experiments. RESULTS: Our findings revealed significant downregulation of miR-149-5p in LPS-stimulated endothelial cells. Restoring miR-149-5p expression upregulated tight/adherens junction proteins (ZO-1, occludin, VE-cadherin) and suppressed ICAM1 expression. In CLP mice, agomiR-149-5p attenuated lung injury by reducing alveolar edema, protein leakage, and immune cell infiltration, and by improving endothelial barrier function. Mechanistically, dual-luciferase assays confirmed direct binding of miR-149-5p to the ABCA1. ABCA1 knockdown mimicked the protective effects of miR-149-5p, while its overexpression exacerbated barrier dysfunction; furthermore, ABCA1 restoration abolished miR-149-5p-mediated protection. CONCLUSIONS: The miR-149-5p/ABCA1 axis represents a novel regulatory mechanism of endothelial homeostasis in sepsis-induced ALI. AgomiR-149-5p delivery demonstrates therapeutic potential by restoring barrier integrity and suppressing inflammation, offering a targeted strategy for critical care management.