title: Organ of Corti and Stria Vascularis: Is there an Interdependence for Survival?
abstract: 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.
authors.affiliation: Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska, United States of America.
authors.forename: Huizhan
authors.initials: H
authors.lastname: Liu
authors.affiliation: Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska, United States of America.|Department of Otorhinolaryngology, Beijing Tongren Hospital, Beijing Capital Medical University, Beijing, China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Li
authors.affiliation: Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska, United States of America.|Chongqing Academy of Animal Science, Chongqing, China.
authors.forename: Lei
authors.initials: L
authors.lastname: Chen
authors.affiliation: Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska, United States of America.
authors.forename: Qian
authors.initials: Q
authors.lastname: Zhang
authors.affiliation: Department of Biology, University of Iowa, Iowa City, Iowa, United States of America.
authors.forename: Ning
authors.initials: N
authors.lastname: Pan
authors.affiliation: Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska, United States of America.
authors.forename: David H
authors.initials: DH
authors.lastname: Nichols
authors.affiliation: Department of Pathophysiology, Second Military Medical University, Shanghai, China.
authors.forename: Weiping J
authors.initials: WJ
authors.lastname: Zhang
authors.affiliation: Department of Biology, University of Iowa, Iowa City, Iowa, United States of America.
authors.forename: Bernd
authors.initials: B
authors.lastname: Fritzsch
authors.affiliation: Department of Biomedical Sciences, Creighton University School of Medicine, Omaha, Nebraska, United States of America.
authors.forename: David Z Z
authors.identifier: http://orcid.org/0000-0001-8383-9634
authors.initials: DZ
authors.lastname: He
mesh_terms: D000818:Animals; D051792:Basic Helix-Loop-Helix Proteins / Q000502:physiology*; D004195:Disease Models, Animal; D005260:Female; D006198:Hair Cells, Auditory / Q000166:cytology / Q000502:physiology*; D006309:Hearing / Q000502:physiology; D008297:Male; D040542:Mechanotransduction, Cellular; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D051739:Microphthalmia-Associated Transcription Factor / Q000378:metabolism; D009925:Organ of Corti / Q000166:cytology / Q000502:physiology*; D013316:Stria Vascularis / Q000166:cytology / Q000502:physiology*
chemical_list: D051792:Basic Helix-Loop-Helix Proteins; D051739:Microphthalmia-Associated Transcription Factor; C500943:Atoh1 protein, mouse; C497235:Mitf protein, mouse