miR-214-3p inhibits LPS-induced macrophage inflammation and attenuates the progression of dry eye syndrome by regulating ferroptosis in cells.

Background: Dry eye disease (DED) is an ocular illness caused by insufficient tear secretion or poor tear quality, and inflammation is a key factor in its pathogenesis. Previous studies have shown that miRNAs are important regulatory factors in DED.

Objective: The purpose of this study was to explore the potential mechanism by which miR-214-3p influenced the DED process by regulating the macrophage inflammatory response.

Methods: We induced THP-1 cells to differentiate into M0 macrophages with 100 ng/mL phorbol-12-myristate-13-acetate (PMA) and then added 15 ng/mL lipopolysaccharide (LPS) to induce inflammation. The expression of related genes and proteins was detected via RT‒qPCR, Western blotting, ELISA and immunofluorescence staining; cell viability was measured using the CCK-8 assay; and flow cytometry was used to detect ROS levels.

Results: In tear and serum samples from DED patients, the levels of miR-214-3p, IL-10, and Arg1 were decreased, and the levels of IL-6, TNF-α, IL-1β, and iNOS expression were increased. Moreover, the overexpression of miR-214-3p attenuated the effect of LPS and inhibited M1 polarization and inflammation in macrophages. Mechanistically, miR-214-3p inhibited macrophage ferroptosis by downregulating TFRC expression, thereby inhibiting macrophage M1 polarization and inflammation and alleviating the progression of DED.

Conclusions: Our study indicated that the upregulation of miR-214-3p expression might be a new target for DED therapy.