MicroRNA-17-5p aggravates lipopolysaccharide-induced injury in nasal epithelial cells by targeting Smad7

Background: Globally, rhinitis is one of the most common chronic disorders. Despite availability of drugs to manage the symptomatology of rhinitis, researchers still focus on identification of novel molecular targets for better management. MicroRNAs are implicated in many biological and pathological processes. However, the role of miR-17-5p in rhinitis remains unexplored. This study aimed to explore the role of miR-17-5p in lipopolysaccharide (LPS)-induced injury of nasal epithelial RPMI2650 cells and to elucidate the possible underlying molecular mechanism. Results: LPS damaged RPMI2650 cells by inhibiting cell proliferation, promoting apoptosis, and stimulating the release of inflammatory cytokines. miR-17-5p expression was significantly increased in RPMI2650 cells following treatment with LPS. Furthermore, it was found that overexpression of miR-17-5p led to aggravation of LPS-induced injury. miR-17-5p negatively regulated expression of Smad7; overexpression of Smad7 protected the RPMI2650 cells by inactivating NF-kappa B and Wnt/beta catenin pathways and vice versa. Conclusions: Overexpression of miR-17-5p aggravated LPS-induced damage of RPMI2650 cells. Expression of Smad7 was negatively regulated by miR-17-5p; Smad7 expression inactivated NF-kappa B and Wnt/beta catenin pathways.