GRβ Regulates Glucocorticoid Resistance in Sudden Sensorineural Hearing Loss

Background: In recent years, the incidence of sudden deafness has gradually increased, with a very limited understanding of the etiology and the pathogenesis. Glucocorticoids are the first choice for the treatment, but some hormoneresistant patients are not sensitive to glucocorticoid therapy. The pathogenesis is not yet known. In this study, we aim to construct HEI-OC1 cell line stably overexpressing glucocorticoid receptor beta (GRβ), and identify its exact role in the cases of glucocorticoid-resistant sudden deafness. Method: We used the endotoxin lipopolysaccharide-stimulated cochlear hair cells (HEI-OC1) to investigate the relationship of inflammation factor IL-2, TNF alpha, and SRp30c with the high expression GRβ. We build a stable GRβ high expression HEI-OC1 cell line and clarified its effects on the therapeutic effect from Dexamethasone. MTT assay, colony formation assay, CCK-8 assay, Western blot, and RT-qPCR were utilized for the characterizations. Results: Dexamethasone reduced LPS-induced inflammatory response in HEI-OC1 cells (p<0.05), detected by MTT assay. Dexamethasone could protect HEI-OC1 cells, but its protective effect was weakened due to the transfection of SRp30c overexpression plasmid (p<0.05). The transfection of SRp30c over-expression plasmid in HEI-OC1 cells could elevate the expressions of GRβ (p<0.05). Conclusion: We clarified the mechanisms of high expression of GRβ in glucocorticoid-resistant sudden sensorineural hearing loss, and proved that the inhibition of SRp30c may act as a new treatment way of glucocorticoid-resistant sudden sensorineural hearing loss.