MicroRNA-300/NAMPT regulates inflammatory responses through activation of AMPK/mTOR signaling pathway in neonatal sepsis.

Abstract

Rapid and accurate diagnosis of neonatal sepsis (NS) is highly warranted because of high associated morbidity and mortality. The study aims to evaluate the effects of miR-300 on inflammatory responses in a septic neonate mouse model. A septic mouse model was established by intraperitoneal (i.p.) cecal slurry (CS) injection in order to validate the effect of miR-300 on the inflammatory response in endothelial cells. Bioinformatics tools and luciferase activity were employed to detect the target of miR-300. Serum inflammatory factors were determined by ELISA assay. RT-qPCR and western blot analysis were used to determine the gene expressions. Flow cytometry was employed to evaluate cell apoptosis. Gain- and loss-of-function studies revealed that miR-300 overexpression augmented autophagy, inhibited cell apoptosis, enhanced cell cycle entry in endothelial cells, and decreased inflammatory response through the regulation of pro- and anti-apoptotic factors in endothelial cells. The effect of miR-300on endothelial cells was upregulated after nicotinamide phosphoribosyltransferase (NAMPT) silencing and AMPK/mTOR signaling pathway activation, indicating that miR-300 influences sepsis via suppressing NAMPT and triggering the AMPK/mTOR signaling pathway. Our study provides evidence indicating that overexpressedmiR-300 enhances autophagy by targeting NAMPT through activation of the AMPK/mTOR signaling pathway in septic mouse models, indicating it may serve as a potential therapeutic target for sepsis.