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Kang KW, Sharma K, Park SH, Lee JK, Lee JC, Yi E. NKCC1 in Neonatal Cochlear Support Cells Reloads Ions Necessary for Cochlear Spontaneous Activity. Exp Neurobiol 2024; 33:68-76. [PMID: 38724477 PMCID: PMC11089404 DOI: 10.5607/en24003] [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: 02/29/2024] [Revised: 03/14/2024] [Accepted: 03/28/2024] [Indexed: 05/15/2024] Open
Abstract
In the auditory system, the spontaneous activity of cochlear inner hair cells (IHCs) is initiated by the release of ATP from inner supporting cells (ISCs). This ATP release sets off a cascade, activating purinergic autoreceptors, opening of Ca2+-activated Cl- channel TMEM16A, Cl- efflux and osmotic cell shrinkage. Then, the shrunken ISCs efficiently regain their original volume, suggesting the existence of mechanisms for refilling Cland K+, priming them for subsequent activity. This study explores the potential involvement of NKCCs (Na+-K+-Cl- cotransporters) and KCCs (K+-Cl- cotransporters) in ISC spontaneous activity, considering their capability to transport both Cl- and K+ ions across the cell membrane. Employing a combination of immunohistochemistry, pharmacological interventions, and shRNA experiment, we unveiled the pivotal role of NKCC1 in cochlear spontaneous activity. Immunohistochemistry revealed robust NKCC1 expression in ISCs, persisting until the 2nd postnatal week. Intriguingly, we observed a developmental shift in NKCC1 expression from ISCs to synaptophysin-positive efferent terminals at postnatal day 18, hinting at its potential involvement in modulating synaptic transmission during the post-hearing period. Experiments using bumetanide, a well-known NKCC inhibitor, supported the functional significance of NKCC1 in ISC spontaneous activity. Bumetanide significantly reduced the frequency of spontaneous extracellular potentials (sEP) and spontaneous optical changes (sOCs) in ISCs. NKCC1-shRNA experiments conducted in cultured cochlear tissues further supported these findings, demonstrating a substantial decrease in event frequency and area. Taken together, we revealed the role of NKCC1 in shaping the ISC spontaneous activity that govern auditory pathway development.
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Affiliation(s)
- Kwon-Woo Kang
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Muan 58554, Korea
| | - Kushal Sharma
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Muan 58554, Korea
| | - Shi-Hyun Park
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Muan 58554, Korea
| | - Jae Kwang Lee
- Division of Functional Food Research, Korea Food Research Institute, Wanju 55365, Korea
| | - Justin C. Lee
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon 34141, Korea
| | - Eunyoung Yi
- College of Pharmacy and Natural Medicine Research Institute, Mokpo National University, Muan 58554, Korea
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Kang H, Lee CJ. Transmembrane proteins with unknown function (TMEMs) as ion channels: electrophysiological properties, structure, and pathophysiological roles. Exp Mol Med 2024; 56:850-860. [PMID: 38556553 PMCID: PMC11059273 DOI: 10.1038/s12276-024-01206-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2023] [Revised: 12/27/2023] [Accepted: 01/19/2024] [Indexed: 04/02/2024] Open
Abstract
A transmembrane (TMEM) protein with an unknown function is a type of membrane-spanning protein expressed in the plasma membrane or the membranes of intracellular organelles. Recently, several TMEM proteins have been identified as functional ion channels. The structures and functions of these proteins have been extensively studied over the last two decades, starting with TMEM16A (ANO1). In this review, we provide a summary of the electrophysiological properties of known TMEM proteins that function as ion channels, such as TMEM175 (KEL), TMEM206 (PAC), TMEM38 (TRIC), TMEM87A (GolpHCat), TMEM120A (TACAN), TMEM63 (OSCA), TMEM150C (Tentonin3), and TMEM43 (Gapjinc). Additionally, we examine the unique structural features of these channels compared to those of other well-known ion channels. Furthermore, we discuss the diverse physiological roles of these proteins in lysosomal/endosomal/Golgi pH regulation, intracellular Ca2+ regulation, spatial memory, cell migration, adipocyte differentiation, and mechanical pain, as well as their pathophysiological roles in Parkinson's disease, cancer, osteogenesis imperfecta, infantile hypomyelination, cardiomyopathy, and auditory neuropathy spectrum disorder. This review highlights the potential for the discovery of novel ion channels within the TMEM protein family and the development of new therapeutic targets for related channelopathies.
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Affiliation(s)
- Hyunji Kang
- Center for Cognition and Sociality, Life Science Cluster, Institute for Basic Science (IBS), 55 Expo-ro, Yuseong-gu, Daejeon, 34126, Republic of Korea
| | - C Justin Lee
- Center for Cognition and Sociality, Life Science Cluster, Institute for Basic Science (IBS), 55 Expo-ro, Yuseong-gu, Daejeon, 34126, Republic of Korea.
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Gu Y, Yao YR, Ding Y, Zhang XW. Reduced expression of transmembrane protein 43 during cardiac hypertrophy leads to worsening heart failure in mice. Exp Biol Med (Maywood) 2023; 248:1437-1445. [PMID: 37697676 PMCID: PMC10666727 DOI: 10.1177/15353702231191111] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Accepted: 04/25/2023] [Indexed: 09/13/2023] Open
Abstract
Transmembrane protein 43 (TMEM43), a member of the transmembrane protein subfamily, was found to be associated with arrhythmogenic right ventricular cardiomyopathy. However, its role in cardiac hypertrophy has not been elucidated. Here, we used a pressure overload-induced cardiac hypertrophy model to explore the role of TMEM43 in heart failure. Mice were subjected to aortic banding (AB) to induce cardiac hypertrophy. The mice were also randomly selected to receive injection of adeno-associated virus 9 (AAV9)-shTMEM43 to knockdown TMEM43 in cardiomyocytes or control AAV9 (ScRNA). Four weeks after AB, the mice were subjected to echocardiography to evaluate cardiac function. Neonatal rat cardiomyocytes (NRCMs) were stimulated with angiotensin II (AngII, 1 μM) and transfected with an adenovirus to over-express TMEM43. We found that TMEM43 was downregulated in mouse hearts and cardiomyocytes poststimulation. Mice with TMEM43 knockdown showed worsening heart failure accompanied by deteriorating cardiac function and exacerbated cardiac hypertrophy and fibrosis at 4 weeks post-AB. NRCMs over-expressing TMEM43 exhibited an ameliorated hypertrophic response. Moreover, we found that TMEM43 deficiency increased nuclear factor kappa B (NF-κB) activation in mouse hearts post-AB, while TMEM43 over-expression reduced NF-κB activation in cardiomyocytes upon AngII stimulation. Thus, we conclude that reduced expression of TMEM43 during cardiac hypertrophy leads to worsening heart failure in mice.
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Affiliation(s)
- Yang Gu
- Department of Cardiology, The Affiliated Huaian No.1 People’s Hospital of Nanjing Medical University, Huai’an 223300, P.R. China
| | - Yi-Ren Yao
- Department of Cardiology, The Affiliated Huaian No.1 People’s Hospital of Nanjing Medical University, Huai’an 223300, P.R. China
| | - Ying Ding
- Department of Cardiology, The Affiliated Huaian No.1 People’s Hospital of Nanjing Medical University, Huai’an 223300, P.R. China
| | - Xi-Wen Zhang
- Department of Cardiology, The Affiliated Huaian No.1 People’s Hospital of Nanjing Medical University, Huai’an 223300, P.R. China
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Jang MW, Lim J, Park MG, Lee JH, Lee CJ. Active role of glia-like supporting cells in the organ of Corti: Membrane proteins and their roles in hearing. Glia 2022; 70:1799-1825. [PMID: 35713516 DOI: 10.1002/glia.24229] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2022] [Revised: 05/23/2022] [Accepted: 05/30/2022] [Indexed: 12/13/2022]
Abstract
The organ of Corti, located in the cochlea in the inner ear, is one of the major sensory organs involved in hearing. The organ of Corti consists of hair cells, glia-like supporting cells, and the cochlear nerve, which work in harmony to receive sound from the outer ear and transmit auditory signals to the cochlear nucleus in the auditory ascending pathway. In this process, maintenance of the endocochlear potential, with a high potassium gradient and clearance of electrolytes and biochemicals in the inner ear, is critical for normal sound transduction. There is an emerging need for a thorough understanding of each cell type involved in this process to understand the sophisticated mechanisms of the organ of Corti. Hair cells have long been thought to be active, playing a primary role in the cochlea in actively detecting and transmitting signals. In contrast, supporting cells are thought to be silent and function to support hair cells. However, growing lines of evidence regarding the membrane proteins that mediate ionic movement in supporting cells have demonstrated that supporting cells are not silent, but actively play important roles in normal signal transduction. In this review, we summarize studies that characterize diverse membrane proteins according to the supporting cell subtypes involved in cochlear physiology and hearing. This review contributes to a better understanding of supporting cell functions and facilitates the development of potential therapeutic tools for hearing loss.
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Affiliation(s)
- Minwoo Wendy Jang
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Republic of Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - Jiwoon Lim
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea.,IBS School, University of Science and Technology (UST), Daejeon, Republic of Korea
| | - Mingu Gordon Park
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Republic of Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - Jae-Hun Lee
- Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea
| | - C Justin Lee
- KU-KIST Graduate School of Converging Science and Technology, Korea University, Seoul, Republic of Korea.,Center for Cognition and Sociality, Institute for Basic Science (IBS), Daejeon, Republic of Korea.,IBS School, University of Science and Technology (UST), Daejeon, Republic of Korea
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Tang PC, V Roche M, Young Um S, Gosstola NC, Young Kim M, Yoon Choi B, Dykxhoorn DM, Zhong Liu X. Characterization of an induced pluripotent stem cell line (UMi040-A) bearing an auditory neuropathy spectrum disorder-associated variant in TMEM43. Stem Cell Res 2022; 61:102758. [PMID: 35364395 PMCID: PMC9089836 DOI: 10.1016/j.scr.2022.102758] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/04/2022] [Revised: 03/14/2022] [Accepted: 03/19/2022] [Indexed: 11/23/2022] Open
Abstract
Hearing loss is one of the most common sensory disorders. TMEM43 is expressed in cochlear glia-like supporting cells (GLSs) and is known to be associated with late-onset auditory neuropathy spectrum disorder (ANSD) and progressive hearing loss. Here, we describe the derivation of an induced pluripotent stem cell (iPSC) line from a patient lymphoblastoid cell line (LCL) carrying a single heterozygous nonsense variant (p.Arg372Ter (c.1114C > T)) in TMEM43 that leads to a truncated protein lacking the 4th transmembrane domain. This cell line can serve as a tool for disease modelling and development of therapeutic approaches to restore inner ear function.
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Affiliation(s)
- Pei-Ciao Tang
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Marie V Roche
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Se Young Um
- Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Nicholas C Gosstola
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Bioengineering, University of Illinois Urbana-Champaign, Urbana, IL 61801, USA
| | - Min Young Kim
- Department of Otorhinolaryngology, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea
| | - Byung Yoon Choi
- Department of Otorhinolaryngology, Seoul National University Bundang Hospital, Seongnam 13620, Republic of Korea
| | - Derek M Dykxhoorn
- John P. Hussman Institute for Human Genomics, John T Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, USA
| | - Xue Zhong Liu
- Department of Otolaryngology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Department of Biochemistry and Molecular Biology, University of Miami Miller School of Medicine, Miami, FL 33136, USA; John P. Hussman Institute for Human Genomics, John T Macdonald Foundation Department of Human Genetics, University of Miami Miller School of Medicine, Miami, FL 33136, USA; Interdisciplinary Stem Cell Institute, University of Miami Miller School of Medicine, Miami, FL 33136, USA.
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