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Park Y, Li J, Ismail Mohamad N, Matthews IR, Santra P, Sherr EH, Chan DK. Noise induces intercellular Ca 2+ signaling waves and the unfolded protein response in the hearing cochlea. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.05.597671. [PMID: 38895437 PMCID: PMC11185706 DOI: 10.1101/2024.06.05.597671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/21/2024]
Abstract
Exposure to loud noise is a common cause of acquired hearing loss. Disruption of subcellular calcium homeostasis and downstream stress pathways in the endoplasmic reticulum and mitochondria, including the unfolded protein response, have been implicated in the pathophysiology of noise-induced hearing loss. However, studies on the association between calcium homeostasis and stress pathways has been limited due to limited ability to measure calcium dynamics in mature-hearing, noise-exposed mice. We used a genetically encoded calcium indicator mouse model in which GcAMP is expressed specifically in hair cells or supporting cells under control of Myo15Cre or Sox2Cre, respectively. We performed live calcium imaging and UPR gene expression analysis in 8-week-old mice exposed to levels of noise that cause cochlear synaptopathy (98 db SPL) or permanent hearing loss (106 dB SPL). UPR activation occurred immediately after noise exposure and was noise dose-dependent, with the pro-apoptotic pathway upregulated only after 106 dB noise exposure. Spontaneous calcium transients in hair cells and intercellular calcium waves in supporting cells, which are present in neonatal cochleae, were quiescent in mature-hearing cochleae, but re-activated upon noise exposure. 106 dB noise exposure was associated with more persistent and expansive ICS wave activity. These findings demonstrate a strong and dose-dependent association between noise exposure, UPR activation, and changes in calcium homeostasis in hair cells and supporting cells, suggesting that targeting these pathways may be effective to develop treatments for noise-induced hearing loss.
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Zhang Y, Tian K, Wei W, Mi W, Lu F, Liu Z, Zhu Q, Zhang X, Geng P, Qiu J, Song Y, Zha D. Translocation of telomerase reverse transcriptase coincided with ATP release in postnatal cochlear supporting cells. Neural Regen Res 2024; 19:1119-1125. [PMID: 37862217 PMCID: PMC10749606 DOI: 10.4103/1673-5374.382862] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2022] [Revised: 05/15/2023] [Accepted: 06/20/2023] [Indexed: 10/22/2023] Open
Abstract
The spontaneous bursts of electrical activity in the developing auditory system are derived from the periodic release of adenosine triphosphate (ATP) by supporting cells in the Kölliker's organ. However, the mechanisms responsible for initiating spontaneous ATP release have not been determined. Our previous study revealed that telomerase reverse transcriptase (TERT) is expressed in the basilar membrane during the first postnatal week. Its role in cochlear development remains unclear. In this study, we investigated the expression and role of TERT in postnatal cochlea supporting cells. Our results revealed that in postnatal cochlear Kölliker's organ supporting cells, TERT shifts from the nucleus into the cytoplasm over time. We found that the TERT translocation tendency in postnatal cochlear supporting cells in vitro coincided with that observed in vivo. Further analysis showed that TERT in the cytoplasm was mainly located in mitochondria in the absence of oxidative stress or apoptosis, suggesting that TERT in mitochondria plays roles other than antioxidant or anti-apoptotic functions. We observed increased ATP synthesis, release and activation of purine signaling systems in supporting cells during the first 10 postnatal days. The phenomenon that TERT translocation coincided with changes in ATP synthesis, release and activation of the purine signaling system in postnatal cochlear supporting cells suggested that TERT may be involved in regulating ATP release and activation of the purine signaling system. Our study provides a new research direction for exploring the spontaneous electrical activity of the cochlea during the early postnatal period.
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Affiliation(s)
- Yukai Zhang
- Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi Province, China
| | - Keyong Tian
- Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi Province, China
| | - Wei Wei
- Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi Province, China
| | - Wenjuan Mi
- Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi Province, China
| | - Fei Lu
- Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi Province, China
| | - Zhenzhen Liu
- Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi Province, China
| | - Qingwen Zhu
- Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi Province, China
| | - Xinyu Zhang
- Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi Province, China
| | - Panling Geng
- Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi Province, China
| | - Jianhua Qiu
- Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi Province, China
| | - Yongli Song
- Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi Province, China
| | - Dingjun Zha
- Department of Otolaryngology, Xijing Hospital, Fourth Military Medical University, Xi’an, Shaanxi Province, China
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Vlajkovic SM, Thorne PR. Purinergic Signalling in the Cochlea. Int J Mol Sci 2022; 23:ijms232314874. [PMID: 36499200 PMCID: PMC9741428 DOI: 10.3390/ijms232314874] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2022] [Revised: 11/24/2022] [Accepted: 11/25/2022] [Indexed: 11/29/2022] Open
Abstract
The mammalian cochlea is the sensory organ of hearing with a delicate, highly organised structure that supports unique operating mechanisms. ATP release from the secretory tissues of the cochlear lateral wall (stria vascularis) triggers numerous physiological responses by activating P2 receptors in sensory, supporting and neural tissues. Two families of P2 receptors, ATP-gated ion channels (P2X receptors) and G protein-coupled P2Y receptors, activate intracellular signalling pathways that regulate cochlear development, homeostasis, sensory transduction, auditory neurotransmission and response to stress. Of particular interest is a purinergic hearing adaptation, which reflects the critical role of the P2X2 receptor in adaptive cochlear response to elevated sound levels. Other P2 receptors are involved in the maturation of neural processes and frequency selectivity refinement in the developing cochlea. Extracellular ATP signalling is regulated by a family of surface-located enzymes collectively known as "ectonucleotidases" that hydrolyse ATP to adenosine. Adenosine is a constitutive cell metabolite with an established role in tissue protection and regeneration. The differential activation of A1 and A2A adenosine receptors defines the cochlear response to injury caused by oxidative stress, inflammation, and activation of apoptotic pathways. A1 receptor agonism, A2A receptor antagonism, and increasing adenosine levels in cochlear fluids all represent promising therapeutic tools for cochlear rescue from injury and prevention of hearing loss.
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Affiliation(s)
- Srdjan M. Vlajkovic
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- Correspondence: ; Tel.: +64-9-9239782
| | - Peter R. Thorne
- Department of Physiology and The Eisdell Moore Centre, Faculty of Medical and Health Sciences, The University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
- Section of Audiology, School of Population Health, University of Auckland, Private Bag 92019, Auckland 1142, New Zealand
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Kim SH, Choi JY. Purinergic signaling in the peripheral vestibular system. Purinergic Signal 2022; 18:165-176. [PMID: 35344126 DOI: 10.1007/s11302-022-09855-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 02/19/2022] [Indexed: 11/25/2022] Open
Abstract
The inner ear comprises the cochlea and vestibular system, which detect sound and acceleration stimulation, respectively. The function of the inner ear is regulated by ion transport activity among sensory epithelial cells, neuronal cells, non-sensory epithelial cells, and luminal fluid with a unique ionic composition of high [K+] and low [Na+], which enables normal hearing and balance maintenance. One of the important mechanisms regulating ion transport in the inner ear is purinergic signaling. Various purinergic receptors are distributed throughout inner ear epithelial cells and neuronal cells. To date, most studies have focused on the role of purinergic receptors in the cochlea, and few studies have examined these receptors in the vestibular system. As purinergic receptors play an important role in the cochlea, they would likely do the same in the vestibular system, which is fairly similar to the cochlea in cellular structure and function. Based on available studies performed to date, purinergic signaling is postulated to be involved in the regulation of ion homeostasis, protection of hair cells, otoconia formation, and regulation of electrical signaling from the sensory epithelium to vestibular neurons. In this review, the distribution and roles of purinergic receptors in the peripheral vestibular system are summarized and discussed.
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Affiliation(s)
- Sung Huhn Kim
- Department of Otorhinolaryngology, Yonsei University College of Medicine, 50-1 Yonsei-Ro, Seodaemun-Gu, Seoul, 03722, Republic of Korea
| | - Jae Young Choi
- Department of Otorhinolaryngology, Yonsei University College of Medicine, 50-1 Yonsei-Ro, Seodaemun-Gu, Seoul, 03722, Republic of Korea.
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Maul A, Huebner AK, Strenzke N, Moser T, Rübsamen R, Jovanovic S, Hübner CA. The Cl--channel TMEM16A is involved in the generation of cochlear Ca2+ waves and promotes the refinement of auditory brainstem networks in mice. eLife 2022; 11:72251. [PMID: 35129434 PMCID: PMC8871368 DOI: 10.7554/elife.72251] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2021] [Accepted: 02/06/2022] [Indexed: 11/17/2022] Open
Abstract
Before hearing onset (postnatal day 12 in mice), inner hair cells (IHCs) spontaneously fire action potentials, thereby driving pre-sensory activity in the ascending auditory pathway. The rate of IHC action potential bursts is modulated by inner supporting cells (ISCs) of Kölliker’s organ through the activity of the Ca2+-activated Cl--channel TMEM16A (ANO1). Here, we show that conditional deletion of Ano1 (Tmem16a) in mice disrupts Ca2+ waves within Kölliker’s organ, reduces the burst-firing activity and the frequency selectivity of auditory brainstem neurons in the medial nucleus of the trapezoid body (MNTB), and also impairs the functional refinement of MNTB projections to the lateral superior olive. These results reveal the importance of the activity of Kölliker’s organ for the refinement of central auditory connectivity. In addition, our study suggests the involvement of TMEM16A in the propagation of Ca2+ waves, which may also apply to other tissues expressing TMEM16A.
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Affiliation(s)
- Alena Maul
- Neuroscience Department, Max Delbrück Center for Molecular Medicine
| | | | - Nicola Strenzke
- Institute for Auditory Neuroscience, Department of Otolaryngology, University of Göttingen
| | - Tobias Moser
- Institute for Auditory Neuroscience, Department of Otolaryngology, University of Göttingen
| | - Rudolf Rübsamen
- Faculty of Bioscience, Pharmacy and Psychology, University of Leipzig
| | - Saša Jovanovic
- Faculty of Bioscience, Pharmacy and Psychology, University of Leipzig
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Luo Z, Zhang J, Qiao L, Lu F, Liu Z. Mapping Genome-wide Binding Sites of Prox1 in Mouse Cochlea Using the CUT&RUN Approach. Neurosci Bull 2021; 37:1703-1707. [PMID: 34351548 DOI: 10.1007/s12264-021-00757-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2021] [Accepted: 05/25/2021] [Indexed: 11/28/2022] Open
Affiliation(s)
- Zhengnan Luo
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China.,University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Jixiang Zhang
- University of Chinese Academy of Sciences, Beijing, 100049, China.,State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Lianyong Qiao
- State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China
| | - Falong Lu
- University of Chinese Academy of Sciences, Beijing, 100049, China. .,State Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, 100101, China.
| | - Zhiyong Liu
- Institute of Neuroscience, State Key Laboratory of Neuroscience, CAS Center for Excellence in Brain Science and Intelligence Technology, Chinese Academy of Sciences, Shanghai, 200031, China. .,University of Chinese Academy of Sciences, Beijing, 100049, China. .,Shanghai Center for Brain Science and Brain-Inspired Intelligence Technology, Shanghai, 201210, China.
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Wang J, Song Q. Inhibition of connexin 43 induces hearing loss in postnatal mice. Physiol Int 2021. [PMID: 33769954 DOI: 10.1556/2060.2021.00008] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Accepted: 12/09/2020] [Indexed: 11/19/2022]
Abstract
BACKGROUND Connexin 43 (Cx43) is the most ubiquitously expressed member of the family of connexins, constituting gap junctions and mediating cell communication, still its role in hearing loss has been little studied. METHODS Immunohistochemistry was used to detect the expression pattern of Cx43. Spiral ganglia neurons (SGNs) and Corti co-culture were utilized to assay the re-innervation of hair cells by newborn SGNs. Gap19 was utilized to inhibit Cx43 hemichannels. Auditory brainstem responses (ABR) and endocochlear potential (E.P.) were measured to confirm the hearing loss. RESULTS The expression of Cx43 in P14 mice was higher than in P0 and P28 (adult) mice, the earlier time point coinciding with the early inner ear development. Additionally, the growth and synapse generation of fibers were inhibited after Gap 19 treatment of the co-cultures of the Corti and SGNs from newborn mice. Furthermore, the inhibition of Cx43 could increase the ABR threshold and decrease E.P. level in postnatal mice, whereas such an effect was not observed in adult mice. CONCLUSION The function of Cx43 is critical during the early development of mouse cochlea but is dispensable in adult mice.
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Affiliation(s)
- J Wang
- Department of Otolaryngology, Weifang City Hanting District People's Hospital, Weifang 261100, Shandong, China
| | - Q Song
- Department of Otolaryngology, Weifang City Hanting District People's Hospital, Weifang 261100, Shandong, China
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Illes P, Xu GY, Tang Y. Purinergic Signaling in the Central Nervous System in Health and Disease. Neurosci Bull 2020; 36:1239-1241. [PMID: 33146814 DOI: 10.1007/s12264-020-00602-7] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Accepted: 10/14/2020] [Indexed: 12/19/2022] Open
Affiliation(s)
- Peter Illes
- International Collaborative Centre on Big Science Plan for Purine Signaling, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China.,Rudolf-Boehm-Institut für Pharmakologie und Toxikologie, Universitaet Leipzig, Leipzig, 04107, Germany
| | - Guang-Yin Xu
- Institute of Neuroscience, Soochow University, Suzhou, 215123, China
| | - Yong Tang
- International Collaborative Centre on Big Science Plan for Purine Signaling, Chengdu University of Traditional Chinese Medicine, Chengdu, 610075, China. .,Acupuncture and Chronobiology Key Laboratory of Sichuan Province, Chengdu, 610075, China.
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