Stress and survival pathways in the mammalian cochlea.
Studies conducted over the last few years demonstrated that signaling pathways that operate in the organs of Corti (OC) play a central role in survival and death of hair cells. An important goal of molecular otology is to characterize these signaling pathways in normal inner ears and inner ears exposed to a variety of different forms of stress, such as ototoxic substances and noise overexposure. In this study, we used high-performance reverse protein microarray technology and phospho-specific antibodies to examine the activation status of defined molecules involved in cellular signaling. We demonstrate that reverse protein microarrays based on the highly sensitive planar-waveguide technology provide an effective and high-throughput means to assess the activation state of key molecules involved in apoptotic and prosurvival signaling in microdissected OC explants over time. In this study, we show that gentamicin and a specific NF-kappaB inhibitor increase the ratio of phospho-c-Jun/c-Jun in OC explants of postnatal rats soon after exposure to these drugs. In addition, we found a decrease in the phospho-Akt/Akt ratio in OC explants early after NF-kappaB inhibition. Finally, we observed an early and consistent decrease in the phospho-p38/p38 ratio in OC explants exposed to the NF-kappaB inhibitor and only a transient decrease in this ratio in OC examples after gentamicin exposure.
Caelers
Antje
A
Department of Biomedicine, University Hospital Basel and Klinik für Ohren-, Nasen-, Halskrankheiten, University Hospital Basel, Basel, Switzerland.
Radojevic
Vesna
V
Traenkle
Jens
J
Brand
Yves
Y
Bodmer
Daniel
D
D000818:Animals; D015153:Blotting, Western; D002478:Cells, Cultured; D004797:Enzyme-Linked Immunosorbent Assay; D005839:Gentamicins / Q000494:pharmacology; D006198:Hair Cells, Auditory / Q000187:drug effects / Q000378:metabolism*; D048031:JNK Mitogen-Activated Protein Kinases / Q000378:metabolism; D016328:NF-kappa B / Q000037:antagonists & inhibitors / Q000378:metabolism; D009925:Organ of Corti / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D010766:Phosphorylation / Q000187:drug effects; D051057:Proto-Oncogene Proteins c-akt / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D015398:Signal Transduction / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D046888:Tissue Array Analysis
D005839:Gentamicins; D016328:NF-kappa B; D051057:Proto-Oncogene Proteins c-akt; D048031:JNK Mitogen-Activated Protein Kinases