Silence of MEG3 intensifies lipopolysaccharide-stimulated damage of human lung cells through modulating miR-4262.

Acute lung injury (ALI) is a serious threat for health and lives worldwide. Recently, lncRNA MEG3 has been well studied to participate in lung cancer, making us speculate that it may be essential for ALI. ALI was simulated by treatment of LPS in human lung fibroblast WI-38 cells and human PMVECs. Cell viability, migration, apoptosis and MEG3 level were assessed by CCK-8, Transwell, flow cytometry/Western blot and qRT-PCR assays, respectively. Utilizing bioinformatics methods, luciferase activity assay and assessments of cell viability, migration and apoptosis, the possible interacted microRNA were explored. We found that, LPS induced decreases of cell viability, migration and MEG3 expression but promoted cell apoptosis. MEG3 knockdown aggravated LPS-induced injury of WI-38 cells and PMVECs. MEG3 acted as a sponge of miR-4262 and effects of MEG3 knockdown could be alleviated by miR-4262 inhibition. Krüppel-like factor 4 (KLF4) was negatively regulated by miR-4262, and its overexpression ameliorated LPS-induced cell injury. LPS-induced alterations of key kinases in the PI3K/AKT and JAK/STAT pathways were reversed by KLF4 overexpression. In conclusion, MEG3 was down-regulated by LPS and its knockdown aggravated LPS-induced injury of human lung cells through miR-4262-mediated down-regulation of KLF4. The PI3K/AKT and JAK/STAT pathways were implicated.