Discovery of a Novel Non-MET-Mediated Otoprotective Compound Against Aminoglycoside-Induced Ototoxicity

Abstract

Aminoglycoside (AG) antibiotics are indispensable for treating severe infections but frequently cause irreversible hearing loss, with no approved preventive therapies. Using in vivo zebrafish lateral line screening combined with computational scaffold-hopping, we identified a novel class of otoprotective compounds. Starting from the ion channel modulator MR16728, we discovered compound 28510 as a potent lead compound. Compound 28510 provided robust, dose-dependent protection against AG-induced hair cell damage, restoring neuromast hair cell integrity to near-control levels in acute assays and demonstrating broad efficacy across clinically relevant AGs (gentamicin, tobramycin, amikacin, streptomycin) in chronic exposures. Importantly, 28510 exhibited a favorable therapeutic window, with low micromolar 50% hair cell protection concentration (HC50) values consistently below toxicity thresholds. Mechanistically, FM1-43 and Texas Red-conjugated gentamicin uptake assays revealed that 28510 does not inhibit mechanotransduction (MET) channel-mediated AG entry, distinguishing it from current clinical candidates and pointing to a novel intracellular protective mechanism. 28510 preserved AG antibacterial activity in E. coli assays, supporting its translational compatibility as a co-therapeutic agent. Combinations of 28510 with related analogs did not yield synergistic protection; 28510 alone remained the most effective compound. In silico absorption, distribution, metabolism, and excretion (ADME) predictions further confirmed its highly favorable drug-like properties, including excellent intestinal and oral absorption. Together, these findings establish 28510 as a first-in-class, non-MET-mediated otoprotective lead with broad efficacy and a favorable therapeutic profile, highlighting a new strategy for preventing AG-induced hearing loss.