Middle Ear microRNAs Drive Mucin Gene Response
Gabriel Nahas, Yajun Chen, Apurva Ningundi, Samuel Tercyak, Diego Preciado Objective(s)
To investigate the role of microRNA‐378 (miR‐378) in the regulation of mucin gene expression and inflammatory response in human middle ear epithelial cells (HMEEC) during bacterial infection by non‐typeable Haemophilus influenzae (NTHi).
Methods
Human middle ear epithelial cells (HMEEC) were cultured and transfected with miR‐378 or control miRNA. Post‐transfection, cells were exposed to NTHi lysates. mRNA levels of MUC5B, MUC5AC, and IL‐8 were quantified using RT‐qPCR, and promoter activity was measured via luciferase assays. The effects of miR‐378 on mucin and cytokine gene expression were analyzed.
Results
Transfection with miR‐378 significantly increased the expression of MUC5B (3.6 fold, p < 0.01), MUC5AC (19.1 fold, p < 0.01), and IL‐8 (2.01 fold, p < 0.05) in HMEEC. NTHi exposure reduced MUC5B (1.385 fold, p < 0.05) and MUC5AC (1.61 fold, p < 0.05) gene expression in miR‐378 transfected cells but significantly increased IL‐8 levels (1.32 fold, p < 0.05). Luciferase assays showed that miR‐378 upregulated the promoter activity of MUC5B (1.4 fold, p < 0.01) and MUC5AC (1.6 fold, p < 0.01) genes, indicating its role in transcriptional regulation.
Conclusion
miR‐378 plays a crucial role in promoting mucin overproduction and an inflammatory response in the middle ear epithelium during OM. Targeting miR‐378 could offer a novel therapeutic strategy for preventing the progression from AOM to COM.
Level of Evidence
na Laryngoscope, 2024