Micro-RNA-375 inhibits lung surfactant secretion by altering cytoskeleton reorganization.

Lung surfactant is secreted via exocytosis of lamellar bodies from alveolar epithelial type II cells. Whether microRNAs regulate lung surfactant secretion is unknown. MicroRNA-375 (miR-375) has been shown to be involved in insulin secretion. In this paper, we report that the overexpression of miR-375 inhibited lung surfactant secretion. However, miR-125a, miR-30a, miR-1, miR-382 and miR-101 did not influence lung surfactant secretion. miR-375 had no effects on surfactant synthesis or the formation of lamellar bodies. However, miR-375 did abolish the lung surfactant secretagogue-induced disassembly and reassembly of cytoskeleton. Our results suggest that miR-375 regulates surfactant secretion via the reorganization of cytoskeleton.