Aquaporin 9 promotes LPS-induced Eustachian tube inflammation through PP2A/NF-κB pathway.

Eustachian tube dysfunction (ETD) induced by Eustachian tube (ET) inflammation is an important cause to middle ear effusion and hearing impairment. Here, we found that aquaporin 9 (AQP9) was an important regulator of ET inflammation. AQP9 was upregulated during ET inflammation, while AQP9 deficiency alleviated LPS-induced ET inflammation by upregulating protein phosphatase 2A (PP2A) expression to suppress nuclear factor kappa-B (NF-κB) activation through P65 phosphorylation. In addition, pharmacological inhibition of AQP9 by phloretin similarly alleviated ET inflammation. These findings provide a new target for the treatment of ET inflammation to improve ETD.