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The role of Aquaporins in Hearing Function and Dysfunction. Eur J Cell Biol 2022; 101:151252. [DOI: 10.1016/j.ejcb.2022.151252] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2022] [Revised: 06/09/2022] [Accepted: 06/22/2022] [Indexed: 11/23/2022] Open
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Edvardsson Rasmussen J, Lundström P, Eriksson PO, Rask-Andersen H, Liu W, Laurell G. The Acute Effects of Furosemide on Na-K-Cl Cotransporter-1, Fetuin-A and Pigment Epithelium-Derived Factor in the Guinea Pig Cochlea. Front Mol Neurosci 2022; 15:842132. [PMID: 35392272 PMCID: PMC8981210 DOI: 10.3389/fnmol.2022.842132] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Accepted: 02/22/2022] [Indexed: 11/28/2022] Open
Abstract
Background Furosemide is a loop diuretic used to treat edema; however, it also targets the Na-K-Cl cotransporter-1 (NKCC1) in the inner ear. In very high doses, furosemide abolishes the endocochlear potential (EP). The aim of the study was to gain a deeper understanding of the temporal course of the acute effects of furosemide in the inner ear, including the protein localization of Fetuin-A and PEDF in guinea pig cochleae. Material and Method Adult guinea pigs were given an intravenous injection of furosemide in a dose of 100 mg per kg of body weight. The cochleae were studied using immunohistochemistry in controls and at four intervals: 3 min, 30 min, 60 min and 120 min. Also, cochleae of untreated guinea pigs were tested for Fetuin-A and PEDF mRNA using RNAscope® technology. Results At 3 min, NKCC1 staining was abolished in the type II fibrocytes in the spiral ligament, followed by a recovery period of up to 120 min. In the stria vascularis, the lowest staining intensity of NKCC1 presented after 30 min. The spiral ganglion showed a stable staining intensity for the full 120 min. Fetuin-A protein and mRNA were detected in the spiral ganglion type I neurons, inner and outer hair cells, pillar cells, Deiters cells and the stria vascularis. Furosemide induced an increased staining intensity of Fetuin-A at 120 min. PEDF protein and mRNA were found in the spiral ganglia type I neurons, the stria vascularis, and in type I and type II fibrocytes of the spiral ligament. PEDF protein staining intensity was high in the pillar cells in the organ of Corti. Furosemide induced an increased staining intensity of PEDF in type I neurons and pillar cells after 120 min. Conclusion The results indicate rapid furosemide-induced changes of NKCC1 in the type II fibrocytes. This could be part of the mechanism that causes reduction of the EP within minutes after high dose furosemide injection. Fetuin-A and PEDF are present in many cells of the cochlea and probably increase after furosemide exposure, possibly as an otoprotective response.
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Zhang Q, Ota T, Yoshida T, Ino D, Sato MP, Doi K, Horii A, Nin F, Hibino H. Electrochemical properties of the non-excitable tissue stria vascularis of the mammalian cochlea are sensitive to sounds. J Physiol 2021; 599:4497-4516. [PMID: 34426971 DOI: 10.1113/jp281981] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 08/18/2021] [Indexed: 11/08/2022] Open
Abstract
Excitable cochlear hair cells convert the mechanical energy of sounds into the electrical signals necessary for neurotransmission. The key process is cellular depolarization via K+ entry from K+ -enriched endolymph through hair cells' mechanosensitive channels. Positive 80 mV potential in endolymph accelerates the K+ entry, thereby sensitizing hearing. This potential represents positive extracellular potential within the epithelial-like stria vascularis; the latter potential stems from K+ equilibrium potential (EK ) across the strial membrane. Extra- and intracellular [K+ ] determining EK are likely maintained by continuous unidirectional circulation of K+ through a putative K+ transport pathway containing hair cells and stria. Whether and how the non-excitable tissue stria vascularis responds to acoustic stimuli remains unclear. Therefore, we analysed a cochlear portion for the best frequency, 1 kHz, by theoretical and experimental approaches. We have previously developed a computational model that integrates ion channels and transporters in the stria and hair cells into a circuit and described a circulation current composed of K+ . Here, in this model, mimicking of hair cells' K+ flow induced by a 1 kHz sound modulated the circulation current and affected the strial ion transport mechanisms; the latter effect resulted in monotonically decreasing potential and increasing [K+ ] in the extracellular strial compartment. Similar results were obtained when the stria in acoustically stimulated animals was examined using microelectrodes detecting the potential and [K+ ]. Measured potential dynamics mirrored the EK change. Collectively, because stria vascularis is electrically coupled to hair cells by the circulation current in vivo too, the strial electrochemical properties respond to sounds. KEY POINTS: A highly positive potential of +80 mV in K+ -enriched endolymph in the mammalian cochlea accelerates sound-induced K+ entry into excitable sensory hair cells, a process that triggers hearing. This unique endolymphatic potential represents an EK -based battery for a non-excitable epithelial-like tissue, the stria vascularis. To examine whether and how the stria vascularis responds to sounds, we used our computational model, in which strial channels and transporters are serially connected to those hair cells in a closed-loop circuit, and found that mimicking hair cell excitation by acoustic stimuli resulted in increased extracellular [K+ ] and decreased the battery's potential within the stria. This observation was overall verified by electrophysiological experiments using live guinea pigs. The sensitivity of electrochemical properties of the stria to sounds indicates that this tissue is electrically coupled to hair cells by a radial ionic flow called a circulation current.
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Affiliation(s)
- Qi Zhang
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.,Department of Molecular Physiology, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi-dori, Niigata, Japan.,Department of Otolaryngology Head and Neck Surgery, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi-dori, Niigata, Japan
| | - Takeru Ota
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Takamasa Yoshida
- Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Maidashi, Fukuoka, Japan
| | - Daisuke Ino
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan
| | - Mitsuo P Sato
- Department of Otolaryngology, Kindai University Faculty of Medicine, Osaka, Japan
| | - Katsumi Doi
- Department of Otolaryngology, Kindai University Faculty of Medicine, Osaka, Japan
| | - Arata Horii
- Department of Otolaryngology Head and Neck Surgery, Niigata University Graduate School of Medical and Dental Sciences, Asahimachi-dori, Niigata, Japan
| | - Fumiaki Nin
- Department of Physiology, Division of Biological Principles, Graduate School of Medicine, Gifu University, Yanagido, Gifu, Japan
| | - Hiroshi Hibino
- Division of Glocal Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Osaka, Japan.,AMED, AMED-CREST, Osaka, Japan
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Peeleman N, Verdoodt D, Ponsaerts P, Van Rompaey V. On the Role of Fibrocytes and the Extracellular Matrix in the Physiology and Pathophysiology of the Spiral Ligament. Front Neurol 2020; 11:580639. [PMID: 33193034 PMCID: PMC7653186 DOI: 10.3389/fneur.2020.580639] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Accepted: 09/10/2020] [Indexed: 12/19/2022] Open
Abstract
The spiral ligament in the cochlea has been suggested to play a significant role in the pathophysiology of different etiologies of strial hearing loss. Spiral ligament fibrocytes (SLFs), the main cell type in the lateral wall, are crucial in maintaining the endocochlear potential and regulating blood flow. SLF dysfunction can therefore cause cochlear dysfunction and thus hearing impairment. Recent studies have highlighted the role of SLFs in the immune response of the cochlea. In contrast to sensory cells in the inner ear, SLFs (more specifically type III fibrocytes) have also demonstrated the ability to regenerate after different types of trauma such as drug toxicity and noise. SLFs are responsible for producing proteins, such as collagen and cochlin, that create an adequate extracellular matrix to thrive in. Any dysfunction of SLFs or structural changes to the extracellular matrix can significantly impact hearing function. However, SLFs may prove useful in restoring hearing by their potential to regenerate cells in the spiral ligament.
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Affiliation(s)
- Noa Peeleman
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium
| | - Dorien Verdoodt
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.,Laboratory of Experimental Hematology, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Peter Ponsaerts
- Laboratory of Experimental Hematology, Vaccine and Infectious Disease Institute (Vaxinfectio), University of Antwerp, Antwerp, Belgium
| | - Vincent Van Rompaey
- Department of Translational Neurosciences, Faculty of Medicine and Health Sciences, University of Antwerp, Antwerp, Belgium.,Department of Otorhinolaryngology and Head and Neck Surgery, Antwerp University Hospital, Edegem, Belgium
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5
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Korrapati S, Taukulis I, Olszewski R, Pyle M, Gu S, Singh R, Griffiths C, Martin D, Boger E, Morell RJ, Hoa M. Single Cell and Single Nucleus RNA-Seq Reveal Cellular Heterogeneity and Homeostatic Regulatory Networks in Adult Mouse Stria Vascularis. Front Mol Neurosci 2019; 12:316. [PMID: 31920542 PMCID: PMC6933021 DOI: 10.3389/fnmol.2019.00316] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2019] [Accepted: 12/05/2019] [Indexed: 12/20/2022] Open
Abstract
The stria vascularis (SV) generates the endocochlear potential (EP) in the inner ear and is necessary for proper hair cell mechanotransduction and hearing. While channels belonging to SV cell types are known to play crucial roles in EP generation, relatively little is known about gene regulatory networks that underlie the ability of the SV to generate and maintain the EP. Using single cell and single nucleus RNA-sequencing, we identify and validate known and rare cell populations in the SV. Furthermore, we establish a basis for understanding molecular mechanisms underlying SV function by identifying potential gene regulatory networks as well as druggable gene targets. Finally, we associate known deafness genes with adult SV cell types. This work establishes a basis for dissecting the genetic mechanisms underlying the role of the SV in hearing and will serve as a basis for designing therapeutic approaches to hearing loss related to SV dysfunction.
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Affiliation(s)
- Soumya Korrapati
- Auditory Development and Restoration Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
| | - Ian Taukulis
- Auditory Development and Restoration Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
| | - Rafal Olszewski
- Auditory Development and Restoration Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
| | - Madeline Pyle
- Auditory Development and Restoration Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
| | - Shoujun Gu
- Auditory Development and Restoration Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
| | - Riya Singh
- Auditory Development and Restoration Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
| | - Carla Griffiths
- Auditory Development and Restoration Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
| | - Daniel Martin
- Biomedical Research Informatics Office, National Institute of Dental and Craniofacial Research, National Institutes of Health, Bethesda, MD, United States
| | - Erich Boger
- Genomics and Computational Biology Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
| | - Robert J. Morell
- Genomics and Computational Biology Core, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
| | - Michael Hoa
- Auditory Development and Restoration Program, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, MD, United States
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Uchida S, Asai Y, Kariya Y, Tsumoto K, Hibino H, Honma M, Abe T, Nin F, Kurata Y, Furutani K, Suzuki H, Kitano H, Inoue R, Kurachi Y. Integrative and theoretical research on the architecture of a biological system and its disorder. J Physiol Sci 2019; 69:433-451. [PMID: 30868372 PMCID: PMC6456489 DOI: 10.1007/s12576-019-00667-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/27/2018] [Accepted: 02/08/2019] [Indexed: 11/28/2022]
Abstract
An organism stems from assemblies of a variety of cells and proteins. This complex system serves as a unit, and it exhibits highly sophisticated functions in response to exogenous stimuli that change over time. The complete sequencing of the entire human genome has allowed researchers to address the enigmas of life and disease at the gene- or molecular-based level. The consequence of such studies is the rapid accumulation of a multitude of data at multiple levels, ranging from molecules to the whole body, that has necessitated the development of entirely new concepts, tools, and methodologies to analyze and integrate these data. This necessity has given birth to systems biology, an advanced theoretical and practical research framework that has totally changed the directions of not only basic life science but also medicine. During the symposium of the 95th Annual Meeting of The Physiological Society of Japan 2018, five researchers reported on their respective studies on systems biology. The topics included reactions of drugs, ion-transport architecture in an epithelial system, multi-omics in renal disease, cardiac electrophysiological systems, and a software platform for computer simulation. In this review article these authors have summarized recent achievements in the field and discuss next-generation studies on health and disease.
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Affiliation(s)
- Shinichi Uchida
- Department of Nephrology, Graduate Schools of Medical and Dental Sciences, Tokyo Medical and Dental University, 1-5-45 Yushima, Bunkyo, Tokyo, 113-8519, Japan
| | - Yoshiyuki Asai
- Department of Systems Bioinformatics, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan
| | - Yoshiaki Kariya
- Department of Pharmacy, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Kunichika Tsumoto
- Division of Molecular and Cellular Pharmacology, Department of Pharmacology, Osaka University, Suita, Japan.,Center for Advanced Medical Engineering and Informatics, Osaka University, Suita, Japan.,Department of Physiology II, Kanazawa Medical University, Ishikawa, 920-0293, Japan
| | - Hiroshi Hibino
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan. .,AMED-CREST, AMED, Niigata, Japan.
| | - Masashi Honma
- Department of Pharmacy, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Takeshi Abe
- Department of Systems Bioinformatics, Yamaguchi University Graduate School of Medicine, Ube, Yamaguchi, 755-8505, Japan
| | - Fumiaki Nin
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan.,AMED-CREST, AMED, Niigata, Japan
| | - Yasutaka Kurata
- Department of Physiology II, Kanazawa Medical University, Ishikawa, 920-0293, Japan
| | - Kazuharu Furutani
- Department of Physiology and Membrane Biology, University of California Davis, Davis, 95616, USA
| | - Hiroshi Suzuki
- Department of Pharmacy, The University of Tokyo Hospital, 7-3-1, Hongo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Hiroaki Kitano
- The Systems Biology Institute, Shinagawa-ku, Tokyo, 108-0071, Japan
| | - Ryuji Inoue
- Department of Physiology, Fukuoka University School of Medicine, 7-45-1 Nanakuma, Jonan-ku, Fukuoka, 814-0180, Japan.
| | - Yoshihisa Kurachi
- Division of Molecular and Cellular Pharmacology, Department of Pharmacology, Osaka University, Suita, Japan. .,Center for Advanced Medical Engineering and Informatics, Osaka University, Suita, Japan.
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7
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Watabe T, Xu M, Watanabe M, Nabekura J, Higuchi T, Hori K, Sato MP, Nin F, Hibino H, Ogawa K, Masuda M, Tanaka KF. Time-controllable Nkcc1 knockdown replicates reversible hearing loss in postnatal mice. Sci Rep 2017; 7:13605. [PMID: 29051615 PMCID: PMC5648887 DOI: 10.1038/s41598-017-13997-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2017] [Accepted: 10/04/2017] [Indexed: 11/08/2022] Open
Abstract
Identification of the causal effects of specific proteins on recurrent and partially reversible hearing loss has been difficult because of the lack of an animal model that provides reversible gene knockdown. We have developed the transgenic mouse line Actin-tTS::Nkcc1 tetO/tetO for manipulatable expression of the cochlear K+ circulation protein, NKCC1. Nkcc1 transcription was blocked by the binding of a tetracycline-dependent transcriptional silencer to the tetracycline operator sequences inserted upstream of the Nkcc1 translation initiation site. Administration of the tetracycline derivative doxycycline reversibly regulated Nkcc1 knockdown. Progeny from pregnant/lactating mothers fed doxycycline-free chow from embryonic day 0 showed strong suppression of Nkcc1 expression (~90% downregulation) and Nkcc1 null phenotypes at postnatal day 35 (P35). P35 transgenic mice from mothers fed doxycycline-free chow starting at P0 (delivery) showed weaker suppression of Nkcc1 expression (~70% downregulation) and less hearing loss with mild cochlear structural changes. Treatment of these mice at P35 with doxycycline for 2 weeks reactivated Nkcc1 transcription to control levels and improved hearing level at high frequency; i.e., these doxycycline-treated mice exhibited partially reversible hearing loss. Thus, development of the Actin-tTS::Nkcc1 tetO/tetO transgenic mouse line provides a mouse model for the study of variable hearing loss through reversible knockdown of Nkcc1.
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Affiliation(s)
- Takahisa Watabe
- Department of Otolaryngology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Ming Xu
- Department of Neuropsychiatry, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Miho Watanabe
- Department of Neurophysiology, Hamamatsu University School of Medicine, 1-20-1 Handayama, Higashi-ku, Hamamatsu city, Shizuoka, 431-3192, Japan
| | - Junichi Nabekura
- Division of Homeostatic Development, National Institute for Physiological Sciences, 38 Nishigonaka Myodaiji, Okazaki, Aichi, 444-8585, Japan
| | - Taiga Higuchi
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
| | - Karin Hori
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
| | - Mitsuo P Sato
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
| | - Fumiaki Nin
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
| | - Hiroshi Hibino
- Department of Molecular Physiology, Niigata University School of Medicine, 757 Ichibancho, Asahimachi-dori, Chuo-ku, Niigata-shi, Niigata, 951-8510, Japan
- Center for Transdisciplinary Research, Niigata University, 8050 Ikarashi 2-no-cho, Nishi-ku, Niigata, 950-2181, Japan
| | - Kaoru Ogawa
- Department of Otolaryngology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan
| | - Masatsugu Masuda
- Department of Otolaryngology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
- Department of Otolaryngology, Kyorin University School of Medicine, 6-20-2 Shinkawa, Mitaka-shi, Tokyo, 181-8611, Japan.
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo, 160-8582, Japan.
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Nin F, Yoshida T, Murakami S, Ogata G, Uetsuka S, Choi S, Doi K, Sawamura S, Inohara H, Komune S, Kurachi Y, Hibino H. Computer modeling defines the system driving a constant current crucial for homeostasis in the mammalian cochlea by integrating unique ion transports. NPJ Syst Biol Appl 2017; 3:24. [PMID: 28861279 PMCID: PMC5572463 DOI: 10.1038/s41540-017-0025-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2017] [Revised: 07/10/2017] [Accepted: 07/28/2017] [Indexed: 11/09/2022] Open
Abstract
The cochlear lateral wall-an epithelial-like tissue comprising inner and outer layers-maintains +80 mV in endolymph. This endocochlear potential supports hearing and represents the sum of all membrane potentials across apical and basolateral surfaces of both layers. The apical surfaces are governed by K+ equilibrium potentials. Underlying extracellular and intracellular [K+] is likely controlled by the "circulation current," which crosses the two layers and unidirectionally flows throughout the cochlea. This idea was conceptually reinforced by our computational model integrating ion channels and transporters; however, contribution of the outer layer's basolateral surface remains unclear. Recent experiments showed that this basolateral surface transports K+ using Na+, K+-ATPases and an unusual characteristic of greater permeability to Na+ than to other ions. To determine whether and how these machineries are involved in the circulation current, we used an in silico approach. In our updated model, the outer layer's basolateral surface was provided with only Na+, K+-ATPases, Na+ conductance, and leak conductance. Under normal conditions, the circulation current was assumed to consist of K+ and be driven predominantly by Na+, K+-ATPases. The model replicated the experimentally measured electrochemical properties in all compartments of the lateral wall, and endocochlear potential, under normal conditions and during blocking of Na+, K+-ATPases. Therefore, the circulation current across the outer layer's basolateral surface depends primarily on the three ion transport mechanisms. During the blockage, the reduced circulation current partially consisted of transiently evoked Na+ flow via the two conductances. This work defines the comprehensive system driving the circulation current.
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Affiliation(s)
- Fumiaki Nin
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, Japan.,Center for Transdisciplinary Research, Niigata University, Niigata, Japan.,AMED-CREST, AMED, Niigata, Japan
| | - Takamasa Yoshida
- Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan
| | - Shingo Murakami
- Department of Physiology, School of Medicine, Toho University, Tokyo, Japan
| | - Genki Ogata
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, Japan.,Center for Transdisciplinary Research, Niigata University, Niigata, Japan
| | - Satoru Uetsuka
- Department of Otorhinolaryngology-Head and Neck Surgery, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Samuel Choi
- Department of Electrical and Electronics Engineering, Niigata University, Niigata, Japan
| | - Katsumi Doi
- Department of Otolaryngology, Faculty of Medicine, Kindai University, Osakasayama, Japan
| | - Seishiro Sawamura
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, Japan
| | - Hidenori Inohara
- Department of Otorhinolaryngology-Head and Neck Surgery, Graduate School of Medicine, Osaka University, Suita, Japan
| | - Shizuo Komune
- Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.,Division of Otolaryngology-Head and Neck Surgery, Yuaikai Oda Hospital, Kashima, Japan
| | - Yoshihisa Kurachi
- Division of Molecular and Cellular Pharmacology, Department of Pharmacology, Graduate School of Medicine, Osaka University, Suita, Japan.,The Global Center for Medical Engineering and Informatics, Osaka University, Suita, Japan
| | - Hiroshi Hibino
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, Japan.,Center for Transdisciplinary Research, Niigata University, Niigata, Japan.,AMED-CREST, AMED, Niigata, Japan
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9
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Liu W, Schrott-Fischer A, Glueckert R, Benav H, Rask-Andersen H. The Human "Cochlear Battery" - Claudin-11 Barrier and Ion Transport Proteins in the Lateral Wall of the Cochlea. Front Mol Neurosci 2017; 10:239. [PMID: 28848383 PMCID: PMC5554435 DOI: 10.3389/fnmol.2017.00239] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2017] [Accepted: 07/14/2017] [Indexed: 11/21/2022] Open
Abstract
Background: The cochlea produces an electric field potential essential for hair cell transduction and hearing. This biological “battery” is situated in the lateral wall of the cochlea and contains molecular machinery that secretes and recycles K+ ions. Its functioning depends on junctional proteins that restrict the para-cellular escape of ions. The tight junction protein Claudin-11 has been found to be one of the major constituents of this barrier that maintains ion gradients (Gow et al., 2004; Kitajiri et al., 2004a). We are the first to elucidate the human Claudin-11 framework and the associated ion transport machinery using super-resolution fluorescence illumination microscopy (SR-SIM). Methods: Archival cochleae obtained during meningioma surgery were used for SR-SIM together with transmission electron microscopy after ethical consent. Results: Claudin-11-expressing cells formed parallel tight junction lamellae that insulated the epithelial syncytium of the stria vascularis and extended to the suprastrial region. Intercellular gap junctions were found between the barrier cells and fibrocytes. Conclusion: Transmission electron microscopy, confocal microscopy and SR-SIM revealed exclusive cell specialization in the various subdomains of the lateral wall of the human cochlea. The Claudin-11-expressing cells exhibited both conductor and isolator characteristics, and these micro-porous separators may selectively mediate the movement of charged units to the intrastrial space in a manner that is analogous to a conventional electrochemical “battery.” The function and relevance of this battery for the development of inner ear disease are discussed.
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Affiliation(s)
- Wei Liu
- Department of Surgical Sciences, Section of Otolaryngology, Uppsala University HospitalUppsala, Sweden
| | | | - Rudolf Glueckert
- Department of Otolaryngology, Medical University of InnsbruckInnsbruck, Austria
| | | | - Helge Rask-Andersen
- Department of Surgical Sciences, Head and Neck Surgery, Section of Otolaryngology, Uppsala University HospitalUppsala, Sweden
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10
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Ogata G, Ishii Y, Asai K, Sano Y, Nin F, Yoshida T, Higuchi T, Sawamura S, Ota T, Hori K, Maeda K, Komune S, Doi K, Takai M, Findlay I, Kusuhara H, Einaga Y, Hibino H. A microsensing system for the in vivo real-time detection of local drug kinetics. Nat Biomed Eng 2017; 1:654-666. [PMID: 31015607 DOI: 10.1038/s41551-017-0118-5] [Citation(s) in RCA: 49] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2016] [Accepted: 06/30/2017] [Indexed: 01/21/2023]
Abstract
Real-time recording of the kinetics of systemically administered drugs in in vivo microenvironments may accelerate the development of effective medical therapies. However, conventional methods require considerable analyte quantities, have low sampling rates and do not address how drug kinetics correlate with target function over time. Here, we describe the development and application of a drug-sensing system consisting of a glass microelectrode and a microsensor composed of boron-doped diamond with a tip of around 40 μm in diameter. We show that, in the guinea pig cochlea, the system can measure-simultaneously and in real time-changes in the concentration of bumetanide (a diuretic that is ototoxic but applicable to epilepsy treatment) and the endocochlear potential underlying hearing. In the rat brain, we tracked the kinetics of the drug and the local field potentials representing neuronal activity. We also show that the actions of the antiepileptic drug lamotrigine and the anticancer reagent doxorubicin can be monitored in vivo. Our microsensing system offers the potential to detect pharmacological and physiological responses that might otherwise remain undetected.
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Affiliation(s)
- Genki Ogata
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, 951-8510, Japan.,Center for Transdisciplinary Research, Niigata University, Niigata, 950-2181, Japan
| | - Yuya Ishii
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, 223-8522, Japan
| | - Kai Asai
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, 223-8522, Japan
| | - Yamato Sano
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Fumiaki Nin
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, 951-8510, Japan.,Center for Transdisciplinary Research, Niigata University, Niigata, 950-2181, Japan
| | - Takamasa Yoshida
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, 951-8510, Japan.,Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Taiga Higuchi
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, 951-8510, Japan
| | - Seishiro Sawamura
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, 951-8510, Japan
| | - Takeru Ota
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, 951-8510, Japan
| | - Karin Hori
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, 951-8510, Japan
| | - Kazuya Maeda
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Shizuo Komune
- Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan.,Division of Otolaryngology-Head and Neck Surgery, Yuaikai Oda Hospital, Kashima, Saga, 849-1311, Japan
| | - Katsumi Doi
- Department of Otolaryngology, Kindai University Faculty of Medicine, Osaka, 589-8511, Japan
| | - Madoka Takai
- Department of Bioengineering, Graduate School of Engineering, The University of Tokyo, Tokyo, 113-8656, Japan
| | - Ian Findlay
- Laboratoire des Cellules Cardiaques et Vasculaires, CNRS ERL 7368, Faculté des Sciences, Université François-Rabelais, Tours, 37200, France
| | - Hiroyuki Kusuhara
- Laboratory of Molecular Pharmacokinetics, Graduate School of Pharmaceutical Sciences, The University of Tokyo, Tokyo, 113-0033, Japan
| | - Yasuaki Einaga
- Department of Chemistry, Faculty of Science and Technology, Keio University, Yokohama, 223-8522, Japan. .,JST-ACCEL, Tokyo, 812-8582, Japan.
| | - Hiroshi Hibino
- Department of Molecular Physiology, Niigata University School of Medicine, Niigata, 951-8510, Japan. .,Center for Transdisciplinary Research, Niigata University, Niigata, 950-2181, Japan.
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11
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Nin F, Yoshida T, Sawamura S, Ogata G, Ota T, Higuchi T, Murakami S, Doi K, Kurachi Y, Hibino H. The unique electrical properties in an extracellular fluid of the mammalian cochlea; their functional roles, homeostatic processes, and pathological significance. Pflugers Arch 2016; 468:1637-49. [PMID: 27568193 PMCID: PMC5026722 DOI: 10.1007/s00424-016-1871-0] [Citation(s) in RCA: 34] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2016] [Accepted: 08/16/2016] [Indexed: 12/13/2022]
Abstract
The cochlea of the mammalian inner ear contains an endolymph that exhibits an endocochlear potential (EP) of +80 mV with a [K(+)] of 150 mM. This unusual extracellular solution is maintained by the cochlear lateral wall, a double-layered epithelial-like tissue. Acoustic stimuli allow endolymphatic K(+) to enter sensory hair cells and excite them. The positive EP accelerates this K(+) influx, thereby sensitizing hearing. K(+) exits from hair cells and circulates back to the lateral wall, which unidirectionally transports K(+) to the endolymph. In vivo electrophysiological assays demonstrated that the EP stems primarily from two K(+) diffusion potentials yielded by [K(+)] gradients between intracellular and extracellular compartments in the lateral wall. Such gradients seem to be controlled by ion channels and transporters expressed in particular membrane domains of the two layers. Analyses of human deafness genes and genetically modified mice suggested the contribution of these channels and transporters to EP and hearing. A computational model, which reconstitutes unidirectional K(+) transport by incorporating channels and transporters in the lateral wall and connects this transport to hair cell transcellular K(+) fluxes, simulates the circulation current flowing between the endolymph and the perilymph. In this model, modulation of the circulation current profile accounts for the processes leading to EP loss under pathological conditions. This article not only summarizes the unique physiological and molecular mechanisms underlying homeostasis of the EP and their pathological relevance but also describes the interplay between EP and circulation current.
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Affiliation(s)
- Fumiaki Nin
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan
| | - Takamasa Yoshida
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan
- Center for Transdisciplinary Research, Niigata University, Niigata, 950-2181, Japan
- Department of Otorhinolaryngology, Graduate School of Medical Sciences, Kyushu University, Fukuoka, 812-8582, Japan
| | - Seishiro Sawamura
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan
| | - Genki Ogata
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan
- Center for Transdisciplinary Research, Niigata University, Niigata, 950-2181, Japan
| | - Takeru Ota
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan
| | - Taiga Higuchi
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan
| | - Shingo Murakami
- Division of Molecular and Cellular Pharmacology, Department of Pharmacology, Osaka University, Osaka, 565-0871, Japan
- Center for Advanced Medical Engineering and Informatics, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
- Department of Physiology, School of Medicine, Toho University, Tokyo, 143-8540, Japan
| | - Katsumi Doi
- Department of Otolaryngology, Kindai University Faculty of Medicine, Osaka, 589-8511, Japan
| | - Yoshihisa Kurachi
- Division of Molecular and Cellular Pharmacology, Department of Pharmacology, Osaka University, Osaka, 565-0871, Japan
- Center for Advanced Medical Engineering and Informatics, Graduate School of Medicine, Osaka University, Osaka, 565-0871, Japan
| | - Hiroshi Hibino
- Department of Molecular Physiology, Niigata University School of Medicine, 1-757 Asahimachi-dori, Chuo-ku, Niigata, Niigata, 951-8510, Japan.
- Center for Transdisciplinary Research, Niigata University, Niigata, 950-2181, Japan.
- AMED-CREST, AMED, Niigata, Japan.
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12
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The unique ion permeability profile of cochlear fibrocytes and its contribution to establishing their positive resting membrane potential. Pflugers Arch 2016; 468:1609-19. [PMID: 27344659 DOI: 10.1007/s00424-016-1853-2] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 05/30/2016] [Accepted: 06/14/2016] [Indexed: 11/27/2022]
Abstract
Eukaryotic cells exhibit negative resting membrane potential (RMP) owing to the high K(+) permeability of the plasma membrane and the asymmetric [K(+)] between the extracellular and intracellular compartments. However, cochlear fibrocytes, which comprise the basolateral surface of a multilayer epithelial-like tissue, exhibit a RMP of +5 to +12 mV in vivo. This positive RMP is critical for the formation of an endocochlear potential (EP) of +80 mV in a K(+)-rich extracellular fluid, endolymph. The epithelial-like tissue bathes fibrocytes in a regular extracellular fluid, perilymph, and apically faces the endolymph. The EP, which is essential for hearing, represents the potential difference across the tissue. Using in vivo electrophysiological approaches, we describe a potential mechanism underlying the unusual RMP of guinea pig fibrocytes. The RMP was +9.0 ± 3.7 mV when fibrocytes were exposed to an artificial control perilymph (n = 28 cochleae). Perilymphatic perfusion of a solution containing low [Na(+)] (1 mM) markedly hyperpolarized the RMP to -31.1 ± 11.2 mV (n = 10; p < 0.0001 versus the control, Tukey-Kramer test after one-way ANOVA). Accordingly, the EP decreased. Little change in RMP was observed when the cells were treated with a high [K(+)] of 30 mM (+10.4 ± 2.3 mV; n = 7; p = 0.942 versus the control). During the infusion of a low [Cl(-)] solution (2.4 mM), the RMP moderately hyperpolarized to -0.9 ± 3.4 mV (n = 5; p < 0.01 versus the control), although the membranes, if governed by Cl(-) permeability, should be depolarized. These observations imply that the fibrocyte membranes are more permeable to Na(+) than K(+) and Cl(-), and this unique profile and [Na(+)] gradient across the membranes contribute to the positive RMP.
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13
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Nin F, Yoshida T, Murakami S, Uetsuka S, Ogata G, Kurachi Y, Hibino H. [Theoretical and experimental analysis of ototoxic mechanism in the spiral ligament fibrocytes by multi-level simulation with ion transports in the cochlea]. Nihon Yakurigaku Zasshi 2016; 147:80-83. [PMID: 26860646 DOI: 10.1254/fpj.147.80] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
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