Outer Hair Cell Motor Protein, Prestin, Is Not a Reliable Serological Biomarker for Mouse Cochlear Damage

Abstract

The motor protein Prestin found in the outer hair cells (OHCs) of the inner ear is responsible for producing high sensitivity and sharp frequency selectivity for mammalian hearing. Some studies have suggested that Prestin could serve as a serological biomarker for cochlear damage since OHCs are highly vulnerable to damage from various sources of insults. However, the reported data are inconsistent and lack appropriate negative controls. To investigate this further, we measured Prestin quantities in the bloodstream using ELISA kits from different companies. Wildtype (WT) mice were exposed to different ototoxic treatments, including noise exposure and ototoxic reagents that kill OHCs rapidly. Prestin-knockout (KO) mice were used as a negative control. Our data show that some ELISA kits were not able to detect Prestin specifically. The ELISA kit that could detect Prestin protein from cochlear homogenates failed to detect Prestin in the bloodstream despite significant damage to OHCs in cochleae. Furthermore, the optical densities of samples, which correlate to Prestin quantities, were significantly influenced by hemolysis in the samples. In conclusion, Prestin from OHCs is not a sensitive and reliable serological biomarker for detecting cochlear damage in mice.