Arid2-IR downregulates miR-132-3p through methylation to promote LPS-induced ALI in pneumonia.

Objective: Arid2-IR is a long non-coding RNA (lncRNA) that promotes renal injury, while its role in lipopolysaccharides (LPS)-induced acute lung injury (ALI) is unknown. Our preliminary sequencing analysis revealed an inverse correlation of Arid2-IR and miR-132-3p, which is known to suppress LPS-induced ALI. Therefore, Arid2-IR and miR-132-3p may interact with each other to participate in LPS-induced ALI in pneumonia. This study aimed to investigate the interaction between Arid2-IR and miR-132-3p in ALI induced by pneumonia.

Materials and methods: Plasma samples were obtained from patients with pneumonia (n = 98) and healthy controls (n = 98) to detect the expression of circulating Arid2-IR and miR-132-3p. The correlation between them was analyzed using Pearson's correlation coefficient. The crosstalk between them in human bronchial epithelial cells (HBEpC) was analyzed through overexpression assay. MSP was applied to determine the methylation of the miR-132-3p gene. Cell viability was evaluated by 2,5-diphenyl-2H-tetrazolium bromide assay.

Results: Arid2-IR was highly upregulated in pneumonia group, while the expression levels of miR-132-3p decreased in pneumonia group compared to that in the controls. Arid2-IR and miR-132-3p were inversely correlated across patient samples. Overexpression of Arid2-IR decreased the expression levels of miR-132-3p in HBEpCs and increased the methylation of miR-132-3p gene. Arid2-IR suppressed the role of miR-132-3p in increasing the viability of HBEpCs induced by LPS.

Discussion and conclusion: Arid2-IR is upregulated in pneumonia and may downregulate miR-132-3p by increasing its methylation to decrease cell viability, thereby promoting LPS-induced ALI in pneumonia.