S-118 | How the brain protects the ear: Transcriptomic changes underlying the role of the efferent system during noise-induced trauma.

Sensory and Motor Systems
Author: VALERIA CASTAGNA | Email: valeriacarolinacastagna@gmail.com

Valeria Castagna^1°2°, Jimena Perez Lloret^3°, Rachel Williams^3°,  Jimena Ballestero^1°, Belén Elgoyhen^2°, Maria Eugenia Gomez Casati^1°, Marcela Lipovsek^3°

^1° Instituto de Farmacología, Facultad de Medicina, Universidad de Buenos Aires, 1121 Buenos Aires, Argentina.
^2° Instituto de Investigaciones en Ingeniería Genética y Biología Molecular, Dr. Héctor N. Torres, Consejo Nacional de Investigaciones Científicas y Técnicas, 1428 Buenos Aires, Argentina.
^3° Ear Institute, UCL, London, UK

Noise-induced hearing loss (NIHL) is becoming a leading type of non-congenital hearing loss, presenting a major societal hazard that begins early in life. Recent studies showed that the medial olivocochlear system (MOC) can mitigate acoustic trauma effects in rodents. We investigated the role of the MOC in NIHL using two mouse models: an α9 nicotinic receptor subunit (nAChR) knock-out (carrying an9 point mutation that leads to enhanced cholinergic activity KO), which lacks cholinergic transmission between MOC neurons and hair cells; and an alpha9 knocking (α9KI) carrying an9 point mutation that leads to enhanced cholinergic activity. Results showed a positive correlation between the degree of hearing loss prevention and the level of cholinergic activity.
This study aimed to analyze transcriptomic changes in specific cell types within the organ of Corti following acoustic trauma, to understand the function of the MOC feedback. WT, α9KI, and α9KO mice at 3 weeks of age were exposed to loud sounds (1-16 kHz, 100 dB SPL, 1hr). One week later, we dissected and flash-froze the organ of Corti. We generated single-nuclei sequencing libraries (Evercode WT, Parse Biosciences) from these tissues. Our initial findings show successful isolation and sequencing of nuclei from inner hair cells (IHCs), outer hair cells (OHCs), supporting cells (SCs), and spiral ganglion neurons (SGNs). Further analyses will clarify the differential responses of each group post-trauma.