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

AIM: 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.

METHODS: 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.

RESULTS: 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.

CONCLUSIONS: 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.