Journal Article

Organ of Corti and Stria Vascularis: Is there an Interdependence for Survival?

Zhang, Weiping J., Fritzsch, Bernd, Liu, Huizhan, Chen, Lei, Zhang, Qian, Pan, Ning, Li, Yi, He, David Z. Z., Nichols, David H.

2016

Overview

Cochlear hair cells and the stria vascularis are critical for normal hearing. Hair cells transduce mechanical stimuli into electrical signals, whereas the stria is responsible for generating the endocochlear potential (EP), which is the driving force for hair cell mechanotransduction. We questioned whether hair cells and the stria interdepend for survival by using two mouse models. Atoh1 conditional knockout mice, which lose all hair cells within four weeks after birth, were used to determine whether the absence of hair cells would affect function and survival of stria. We showed that stria morphology and EP remained normal for long time despite a complete loss of all hair cells. We then used a mouse model that has an abnormal stria morphology and function due to mutation of the Mitf gene to determine whether hair cells are able to survive and transduce sound signals without a normal electrochemical environment in the endolymph. A strial defect, reflected by missing intermediate cells in the stria and by reduction of EP, led to systematic outer hair cell death from the base to the apex after postnatal day 18. However, an 18-mV EP was sufficient for outer hair cell survival. Surprisingly, inner hair cell survival was less vulnerable to reduction of the EP. Our studies show that normal function of the stria is essential for adult outer hair cell survival, while the survival and normal function of the stria vascularis do not depend on functional hair cells.

• Publisher: Public Library of Science,Public Library of Science (PLoS)
• Subject: Animal models / Animals / Basic Helix-Loop-Helix Transcription Factors - physiology / Biology and life sciences / Cell death / Cell survival / Cochlea / Development and progression / Disease Models, Animal / Electrochemistry / Endolymph / Female / Gene expression / Hair / Hair cells / Hair cells (Sensory receptors) / Hair Cells, Auditory - cytology / Hair Cells, Auditory - physiology / Hearing - physiology / Hearing disorders / Hearing loss / Hearing protection / Ligaments / Male / Math1 protein / Mechanical stimuli / Mechanotransduction / Mechanotransduction, Cellular / Medicine / Medicine and health sciences / Mice / Mice, Inbred C57BL / Mice, Knockout / Microphthalmia-Associated Transcription Factor - metabolism / MITF gene / Morphology / Mutation / Organ of Corti / Organ of Corti - cytology / Organ of Corti - physiology / Otolaryngology / Physical Sciences / Physiological aspects / Potassium / Reduction / Research and Analysis Methods / Stria vascularis / Stria Vascularis - cytology / Stria Vascularis - physiology / Survival / Transcription factors