Identification of a series of hair-cell MET channel blockers that protect against aminoglycoside-induced ototoxicity
Emma J. Kenyon, Nerissa K. Kirkwood, Siân R. Kitcher, Richard J. Goodyear, Marco Derudas, Daire M. Cantillon, Sarah Baxendale, Antonio de la Vega de León, Virginia N. Mahieu, Richard T. Osgood, Charlotte Donald Wilson, James C. Bull, Simon J. Waddell, Tanya T. Whitfield, Simon E. Ward, Corné J. Kros, Guy P. Richardson
Emma J. Kenyon, Nerissa K. Kirkwood, Siân R. Kitcher, Richard J. Goodyear, Marco Derudas, Daire M. Cantillon, Sarah Baxendale, Antonio de la Vega de León, Virginia N. Mahieu, Richard T. Osgood, Charlotte Donald Wilson, James C. Bull, Simon J. Waddell, Tanya T. Whitfield, Simon E. Ward, Corné J. Kros, Guy P. Richardson
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Research Article Neuroscience Therapeutics

Identification of a series of hair-cell MET channel blockers that protect against aminoglycoside-induced ototoxicity

Abstract

To identify small molecules that shield mammalian sensory hair cells from the ototoxic side effects of aminoglycoside antibiotics, 10,240 compounds were initially screened in zebrafish larvae, selecting for those that protected lateral-line hair cells against neomycin and gentamicin. When the 64 hits from this screen were retested in mouse cochlear cultures, 8 protected outer hair cells (OHCs) from gentamicin in vitro without causing hair-bundle damage. These 8 hits shared structural features and blocked, to varying degrees, the OHC’s mechano-electrical transducer (MET) channel, a route of aminoglycoside entry into hair cells. Further characterization of one of the strongest MET channel blockers, UoS-7692, revealed it additionally protected against kanamycin and tobramycin and did not abrogate the bactericidal activity of gentamicin. UoS-7692 behaved, like the aminoglycosides, as a permeant blocker of the MET channel; significantly reduced gentamicin–Texas red loading into OHCs; and preserved lateral-line function in neomycin-treated zebrafish. Transtympanic injection of UoS-7692 protected mouse OHCs from furosemide/kanamycin exposure in vivo and partially preserved hearing. The results confirmed the hair-cell MET channel as a viable target for the identification of compounds that protect the cochlea from aminoglycosides and provide a series of hit compounds that will inform the design of future otoprotectants.

Authors

Emma J. Kenyon, Nerissa K. Kirkwood, Siân R. Kitcher, Richard J. Goodyear, Marco Derudas, Daire M. Cantillon, Sarah Baxendale, Antonio de la Vega de León, Virginia N. Mahieu, Richard T. Osgood, Charlotte Donald Wilson, James C. Bull, Simon J. Waddell, Tanya T. Whitfield, Simon E. Ward, Corné J. Kros, Guy P. Richardson

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Figure 1

Screen of 10,240 Life Chemicals Diversity compounds in zebrafish larvae and mouse cochlear cultures.

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Screen of 10,240 Life Chemicals Diversity compounds in zebrafish larvae ...
(A) Dendrogram of compounds grouped by broadly related structure into 5 clusters identified by color. (B–E) Polar scatterplots annotated with dendrogram clusters. Blue dots show “hit” compounds in each cluster obtained in each screen (see Supplemental Figure 1). Blue arrows between the plots indicate compounds passing the previous screen were used in the next. (F–M) Representative examples of neuromasts (F–I) and cochlear cultures (J–M) treated with antibiotic alone (F, H, J, and L) or antibiotic in the presence of one of the hit compounds (G, I, K, and M). Neuromasts (F–I) were labeled with YO-PRO-1 prior to incubation with neomycin alone (F), neomycin and UoS-3606 (G), gentamicin alone (H), or gentamicin and UoS-3606 (I). Cochlear cultures (J–M) were labeled with Texas red phalloidin after treatment with gentamicin alone (J and L) and gentamicin with UoS-7339 (K) or UoS-3606 (M). Hair bundles in K show damage; those in M are normal. Scale bars: 20 μm (J–M).