LncRNA NEAT1 aggravates lipopolysaccharide-induced acute lung injury by regulating the miR-98-5p/TLR4 axis.

ABSTRACT

Although long noncoding RNA nuclear paraspeckle assembly transcript 1 (NEAT1) was reported to be associated with acute lung injury (ALI), its specific mechanism has not been well studied. Mouse and cell ALI models were constructed by lipopolysaccharide (LPS). Cell viability was evaluated by 3-(4,5)-dimethylthiahiazo (-z-y1)-3,5-di- phenytetrazoliumromide assay. Cell death was evaluated by lactate dehydrogenase release (LDH) detection kit and flow cytometry. The levels of cytokines in lung tissues lysates were detected by quantitative real-time PCR (qRT-PCR) and enzyme-linked immunosorbent assay (ELISA). The expression of apoptosis-related markers was detected by Western blot. The relationship between NEAT1, miR-98-5p, and toll-like receptor 4 (TLR4) was determined by bioinformatics prediction, luciferase reporter assay, and RNA immunoprecipitation (RIP) assay. Rescue experiments were performed to determine the role of NEAT1/miR-98-5p/TLR4 in ALI. NEAT1 was significantly upregulated during ALI both in vitro and in vivo. NEAT1 knockdown efficiently attenuated LPS-induced ALI and reduced LPS-induced elevation of cytokines both in vitro and in vivo. NEAT1 negatively regulated miR-98-5p by directly sponging it, and TLR4 was a target of miR-98-5p. MiR-98-5p inhibition or TLR4 overexpression could obviously attenuate the protective effects of NEAT1 knockdown in LPS-treated A549 cells. Our study demonstrated that NEAT1 knockdown alleviated LPS-induced ALI by targeting the miR-98-5p/TLR4 axis.