BUSCADOR RECOLECTA

Digital.CSIC. Repositorio Institucional del CSIC

oai:digital.csic.es:10261/190386

Resumen del póster presentado al 42nd Congress of the Spanish Society of Biochemistry and Molecular Biology (SEBBM), celebrado en Madrid del 16 al 19 de julio de 2019., Ageing of the auditory system is associated with the incremental production of reactive oxygen species (ROS) and the accumulation of oxidative-derived damage in macromolecules, which contribute to cellular malfunction, compromise cell viability and, finally, causes functional decline. The cellular detoxification power partially relies in the production of the cofactor for the activity of key antioxidant enzymes NADPH. This is mainly produced by the glucose-6-phosphate dehydrogenase (G6PD), an enzyme that catalyzes the rate-limiting step in the pentose phosphate pathway. We show here that the transgenic mouse hG6PD-Tg, which shows enhanced NADPH production along life, maintains lower auditory thresholds than wild type mice during ageing. G6PD overexpression preserves irreplaceable cochlear cell populations, thus hG6PD-Tg mice exhibit significantly higher number of inner and outer hair cells (OHC) and more widespread OHC innervation than wild type mice. Transcripts for antioxidant enzymes were significantly increased in 3-month old hG6PD-Tg, particularly remarkable those of glutathione reductase and thioredoxin reductase 1, whose activity depends on NADPH availability. Accordingly, tyrosine modification by nitration in proteins was reduced in 9-month old G6PD-Tg compared with wild type mice. As well as lesser TUNEL positive apoptotic cells were detected in whole mount preparations of the organ of Corti of hG6PD-Tg mice. Western blotting analysis of cochlear extracts further showed increased survival and reduced pro-apoptotic signaling in the transgenic versus the wild type mice. In conclusion, we propose that NADPH overproduction from an early stage is an efficient mechanism to maintain the balance between the generation of ROS and the cell detoxification power along ageing and, therefore to prevent hearing loss progression., This work was supported by FP7-2013-TARGEAR and FEDER/SAF 2014-AGEAR and 2017-HEARCODE., Peer Reviewed