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Seicol BJ, Guo Z, Garrity K, Xie R. Potential uses of auditory nerve stimulation to modulate immune responses in the inner ear and auditory brainstem. Front Integr Neurosci 2023; 17:1294525. [PMID: 38162822 PMCID: PMC10755874 DOI: 10.3389/fnint.2023.1294525] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2023] [Accepted: 12/01/2023] [Indexed: 01/03/2024] Open
Abstract
Bioelectronic medicine uses electrical stimulation of the nervous system to improve health outcomes throughout the body primarily by regulating immune responses. This concept, however, has yet to be applied systematically to the auditory system. There is growing interest in how cochlear damage and associated neuroinflammation may contribute to hearing loss. In conjunction with recent findings, we propose here a new perspective, which could be applied alongside advancing technologies, to use auditory nerve (AN) stimulation to modulate immune responses in hearing health disorders and following surgeries for auditory implants. In this article we will: (1) review the mechanisms of inflammation in the auditory system in relation to various forms of hearing loss, (2) explore nerve stimulation to reduce inflammation throughout the body and how similar neural-immune circuits likely exist in the auditory system (3) summarize current methods for stimulating the auditory system, particularly the AN, and (4) propose future directions to use bioelectronic medicine to ameliorate harmful immune responses in the inner ear and auditory brainstem to treat refractory conditions. We will illustrate how current knowledge from bioelectronic medicine can be applied to AN stimulation to resolve inflammation associated with implantation and disease. Further, we suggest the necessary steps to get discoveries in this emerging field from bench to bedside. Our vision is a future for AN stimulation that includes additional protocols as well as advances in devices to target and engage neural-immune circuitry for therapeutic benefits.
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Affiliation(s)
- Benjamin J. Seicol
- Department of Otolaryngology, The Ohio State University, Columbus, OH, United States
- Department of Neuroscience, The Ohio State University, Columbus, OH, United States
| | - Zixu Guo
- Department of Otolaryngology, The Ohio State University, Columbus, OH, United States
- Department of Neuroscience, The Ohio State University, Columbus, OH, United States
| | - Katy Garrity
- Department of Neuroscience, The Ohio State University, Columbus, OH, United States
| | - Ruili Xie
- Department of Otolaryngology, The Ohio State University, Columbus, OH, United States
- Department of Neuroscience, The Ohio State University, Columbus, OH, United States
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Vélez-Ortega AC, Stepanyan R, Edelmann SE, Torres-Gallego S, Park C, Marinkova DA, Nowacki JS, Sinha GP, Frolenkov GI. TRPA1 activation in non-sensory supporting cells contributes to regulation of cochlear sensitivity after acoustic trauma. Nat Commun 2023; 14:3871. [PMID: 37391431 PMCID: PMC10313773 DOI: 10.1038/s41467-023-39589-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2015] [Accepted: 06/13/2023] [Indexed: 07/02/2023] Open
Abstract
TRPA1 channels are expressed in nociceptive neurons, where they detect noxious stimuli, and in the mammalian cochlea, where their function is unknown. Here we show that TRPA1 activation in the supporting non-sensory Hensen's cells of the mouse cochlea causes prolonged Ca2+ responses, which propagate across the organ of Corti and cause long-lasting contractions of pillar and Deiters' cells. Caged Ca2+ experiments demonstrated that, similar to Deiters' cells, pillar cells also possess Ca2+-dependent contractile machinery. TRPA1 channels are activated by endogenous products of oxidative stress and extracellular ATP. Since both these stimuli are present in vivo after acoustic trauma, TRPA1 activation after noise may affect cochlear sensitivity through supporting cell contractions. Consistently, TRPA1 deficiency results in larger but less prolonged noise-induced temporary shift of hearing thresholds, accompanied by permanent changes of latency of the auditory brainstem responses. We conclude that TRPA1 contributes to the regulation of cochlear sensitivity after acoustic trauma.
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Affiliation(s)
- A Catalina Vélez-Ortega
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, 40536, USA.
| | - Ruben Stepanyan
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, 40536, USA
- Department of Otolaryngology, Case Western Reserve University, Cleveland, OH, 44106, USA
| | - Stephanie E Edelmann
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, 40536, USA
| | - Sara Torres-Gallego
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, 40536, USA
| | - Channy Park
- Department of Head & Neck Surgery, David Geffen School of Medicine, UCLA, Los Angeles, CA, 90095, USA
| | - Desislava A Marinkova
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, 40536, USA
- Department of Pharmacology and Toxicology, University of Arkansas for Medical Sciences, Little Rock, AR, 72205, USA
| | - Joshua S Nowacki
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, 40536, USA
| | - Ghanshyam P Sinha
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, 40536, USA
- Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA, 15261, USA
| | - Gregory I Frolenkov
- Department of Physiology, College of Medicine, University of Kentucky, Lexington, KY, 40536, USA.
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3
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Konkoly J, Kormos V, Gaszner B, Correia P, Berta G, Biró-Sütő T, Zelena D, Pintér E. Transient receptor potential ankyrin 1 ion channel expressed by the Edinger-Westphal nucleus contributes to stress adaptation in murine model of posttraumatic stress disorder. Front Cell Dev Biol 2022; 10:1059073. [PMID: 36561364 PMCID: PMC9763580 DOI: 10.3389/fcell.2022.1059073] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
The centrally projecting Edinger-Westphal nucleus (EWcp) is involved in stress adaptation. Transient receptor potential ankyrin 1 (TRPA1) mRNA was previously shown to be expressed abundantly in mouse and human EWcp urocortin 1 (UCN1) positive neurons and reacted to chronic stress. Since UCN1 neurons are deeply implicated in stress-related disorders, we hypothesized that TRPA1/UCN1 neurons are also affected in posttraumatic stress disorder (PTSD). We examined male Trpa1 wild type (WT) and gene-deficient (KO) mice in the single prolonged stress (SPS) model of PTSD. Two weeks later the behavioral changes were monitored by forced swim test (FST) and restraint. The Trpa1 and Ucn1 mRNA expression and the UCN1 peptide content were assessed by RNAscope in situ hybridization technique combined with immunofluorescence labeling in the EWcp. SPS-induced immobility was lower in Trpa1 KO compared to WT animals, both in the FST and restraint, corresponding to diminished depression-like behavior. The copy number of Trpa1 mRNA decreased significantly in EWcp of WT animals in response to SPS. Higher basal Ucn1 mRNA expression was observed in the EWcp of KO animals, that was not affected by SPS exposure. EWcp neurons of WT animals responded to SPS with substantially increased amount of UCN1 peptide content compared to control animals, whereas such changes were not observable in KO mice. The decreased Trpa1 mRNA expression in the SPS model of PTSD associated with increased neuronal UCN1 peptide content suggests that this cation channel might be involved in the regulation of stress adaptation and may contribute to the pathomechanism of PTSD.
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Affiliation(s)
- János Konkoly
- Department of Pharmacology and Pharmacotherapy, University of Pécs, Medical School, Pécs, Hungary
| | - Viktória Kormos
- Department of Pharmacology and Pharmacotherapy, University of Pécs, Medical School, Pécs, Hungary,*Correspondence: Viktória Kormos,
| | - Balázs Gaszner
- Department of Anatomy, University of Pécs, Medical School, Pécs, Hungary
| | - Pedro Correia
- Department of Physiology, University of Pécs, Medical School, Pécs, Hungary
| | - Gergely Berta
- Department of Medical Biology, University of Pécs, Medical School, Pécs, Hungary,Signal Transduction Research Group, János Szentágothai Research Centre, Pécs, Hungary
| | - Tünde Biró-Sütő
- Department of Pharmacology and Pharmacotherapy, University of Pécs, Medical School, Pécs, Hungary
| | - Dóra Zelena
- Department of Physiology, University of Pécs, Medical School, Pécs, Hungary
| | - Erika Pintér
- Department of Pharmacology and Pharmacotherapy, University of Pécs, Medical School, Pécs, Hungary
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Ramkumar V, Sheth S, Dhukhwa A, Al Aameri R, Rybak L, Mukherjea D. Transient Receptor Potential Channels and Auditory Functions. Antioxid Redox Signal 2022; 36:1158-1170. [PMID: 34465184 PMCID: PMC9221156 DOI: 10.1089/ars.2021.0191] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Significance: Transient receptor potential (TRP) channels are cation-gated channels that serve as detectors of various sensory modalities, such as pain, heat, cold, and taste. These channels are expressed in the inner ear, suggesting that they could also contribute to the perception of sound. This review provides more details on the different types of TRP channels that have been identified in the cochlea to date, focusing on their cochlear distribution, regulation, and potential contributions to auditory functions. Recent Advances: To date, the effect of TRP channels on normal cochlear physiology in mammals is still unclear. These channels contribute, to a limited extent, to normal cochlear physiology such as the hair cell mechanoelectrical transduction channel and strial functions. More detailed information on a number of these channels in the cochlea awaits future studies. Several laboratories focusing on TRPV1 channels have shown that they are responsive to cochlear stressors, such as ototoxic drugs and noise, and regulate cytoprotective and/or cell death pathways. TRPV1 expression in the cochlea is under control of oxidative stress (produced primarily by NOX3 NADPH oxidase) as well as STAT1 and STAT3 transcription factors, which differentially modulate inflammatory and apoptotic signals in the cochlea. Inhibition of oxidative stress or inflammation reduces the expression of TRPV1 channels and protects against cochlear damage and hearing loss. Critical Issues: TRPV1 channels are activated by both capsaicin and cisplatin, which produce differential effects on the inner ear. How these differential actions are produced is yet to be determined. It is clear that TRPV1 is an essential component of cisplatin ototoxicity as knockdown of these channels protects against hearing loss. In contrast, activation of TRPV1 by capsaicin protected against subsequent hearing loss induced by cisplatin. The cellular targets that are influenced by these two drugs to account for their differential profiles need to be fully elucidated. Furthermore, the potential involvement of different TRP channels present in the cochlea in regulating cisplatin ototoxicity needs to be determined. Future Directions: TRPV1 has been shown to mediate the entry of aminoglycosides into the hair cells. Thus, novel otoprotective strategies could involve designing drugs to inhibit entry of aminoglycosides and possibly other ototoxins into cochlear hair cells. TRP channels, including TRPV1, are expressed on circulating and resident immune cells. These receptors modulate immune cell functions. However, whether they are activated by cochlear stressors to initiate cochlear inflammation and ototoxicity needs to be determined. A better understanding of the function and regulation of these TRP channels in the cochlea could enable development of novel treatments for treating hearing loss. Antioxid. Redox Signal. 36, 1158-1170.
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Affiliation(s)
- Vickram Ramkumar
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois, USA
| | - Sandeep Sheth
- Department of Pharmaceutical Sciences, Larkin University College of Pharmacy, Miami, Florida, USA
| | - Asmita Dhukhwa
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois, USA
| | - Raheem Al Aameri
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois, USA
| | - Leonard Rybak
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, Illinois, USA.,Department of Otolaryngology, Southern Illinois University School of Medicine, Springfield, Illinois, USA
| | - Debashree Mukherjea
- Department of Otolaryngology, Southern Illinois University School of Medicine, Springfield, Illinois, USA
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Kim J, Hemachandran S, Cheng AG, Ricci AJ. Identifying targets to prevent aminoglycoside ototoxicity. Mol Cell Neurosci 2022; 120:103722. [PMID: 35341941 PMCID: PMC9177639 DOI: 10.1016/j.mcn.2022.103722] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2021] [Revised: 03/14/2022] [Accepted: 03/19/2022] [Indexed: 12/21/2022] Open
Abstract
Aminoglycosides are potent antibiotics that are commonly prescribed worldwide. Their use carries significant risks of ototoxicity by directly causing inner ear hair cell degeneration. Despite their ototoxic side effects, there are currently no approved antidotes. Here we review recent advances in our understanding of aminoglycoside ototoxicity, mechanisms of drug transport, and promising sites for intervention to prevent ototoxicity.
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Affiliation(s)
- Jinkyung Kim
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Sriram Hemachandran
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA
| | - Alan G Cheng
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA.
| | - Anthony J Ricci
- Department of Otolaryngology-Head and Neck Surgery, Stanford University School of Medicine, Stanford, CA 94305, USA; Department of Molecular and Cellular Physiology, Stanford University School of Medicine, Stanford, CA 94305, USA.
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A Genome-Wide Association Study of Age-Related Hearing Impairment in Middle- and Old-Aged Chinese Twins. BIOMED RESEARCH INTERNATIONAL 2021; 2021:3629624. [PMID: 34337005 PMCID: PMC8314043 DOI: 10.1155/2021/3629624] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Revised: 06/17/2021] [Accepted: 07/03/2021] [Indexed: 11/17/2022]
Abstract
Background Age-related hearing impairment (ARHI) is considered an unpreventable disorder. We aimed to detect specific genetic variants that are potentially related to ARHI via genome-wide association study (GWAS). Methods A sample of 131 dizygotic twins was genotyped for single-nucleotide polymorphism- (SNP-) based GWAS. Gene-based test was performed using VEGAS2. Pathway enrichment analysis was conducted by PASCAL. Results The twins are with a median age of 49 years, of which 128 were females and 134 were males. rs6633657 was the only SNP that reached the genome-wide significance level for better ear hearing level (BEHL) at 2.0 kHz (P = 1.19 × 10-8). Totally, 9, 10, 42, 7, 17, and 5 SNPs were suggestive evidence level for (P < 1 × 10-5) BEHLs at 0.5, 1.0, 2.0, 4.0, and 8.0 kHz and pure tone average (PTA), respectively. Several promising genetic regions in chromosomes (near the C20orf196, AQPEP, UBQLN3, OR51B5, OR51I2, OR52D1, GLTP, GIT2, and PARK2) nominally associated with ARHI were identified. Gene-based analysis revealed 165, 173, 77, 178, 170, and 145 genes nominally associated with BEHLs at 0.5, 1.0, 2.0, 4.0, and 8.0 kHz and PTA, respectively (P < 0.05). For BEHLs at 0.5, 1.0, and 2.0 kHz, the main enriched pathways were phosphatidylinositol signaling system, regulation of ornithine decarboxylase, eukaryotic translation initiation factor (EIF) pathway, amine compound solute carrier (SLC) transporters, synthesis of phosphoinositides (PIPS) at the plasma membrane, and phosphatidylinositols (PI) metabolism. Conclusions The genetic variations reported herein are significantly involved in functional genes and regulatory domains that mediate ARHI pathogenesis. These findings provide clues for the further unraveling of the molecular physiology of hearing functions and identifying novel diagnostic biomarkers and therapeutic targets of ARHI.
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Pang JJ, Gao F, Wu SM. Generators of Pressure-Evoked Currents in Vertebrate Outer Retinal Neurons. Cells 2021; 10:cells10061288. [PMID: 34067375 PMCID: PMC8224636 DOI: 10.3390/cells10061288] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2021] [Revised: 05/13/2021] [Accepted: 05/19/2021] [Indexed: 12/19/2022] Open
Abstract
(1) Background: High-tension glaucoma damages the peripheral vision dominated by rods. How mechanosensitive channels (MSCs) in the outer retina mediate pressure responses is unclear. (2) Methods: Immunocytochemistry, patch clamp, and channel fluorescence were used to study MSCs in salamander photoreceptors. (3) Results: Immunoreactivity of transient receptor potential channel vanilloid 4 (TRPV4) was revealed in the outer plexiform layer, K+ channel TRAAK in the photoreceptor outer segment (OS), and TRPV2 in some rod OS disks. Pressure on the rod inner segment evoked sustained currents of three components: (A) the inward current at <-50 mV (Ipi), sensitive to Co2+; (B) leak outward current at ≥-80 mV (Ipo), sensitive to intracellular Cs+ and ruthenium red; and (C) cation current reversed at ~10 mV (Ipc). Hypotonicity induced slow currents like Ipc. Environmental pressure and light increased the FM 1-43-identified open MSCs in the OS membrane, while pressure on the OS with internal Cs+ closed a Ca2+-dependent current reversed at ~0 mV. Rod photocurrents were thermosensitive and affected by MSC blockers. (4) Conclusions: Rods possess depolarizing (TRPV) and hyperpolarizing (K+) MSCs, which mediate mutually compensating currents between -50 mV and 10 mV, serve as an electrical cushion to minimize the impact of ocular mechanical stress.
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Ghosh S, Stansak K, Walters BJ. Cannabinoid Signaling in Auditory Function and Development. Front Mol Neurosci 2021; 14:678510. [PMID: 34079440 PMCID: PMC8165240 DOI: 10.3389/fnmol.2021.678510] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Accepted: 04/15/2021] [Indexed: 12/20/2022] Open
Abstract
Plants of the genus Cannabis have been used by humans for millennia for a variety of purposes. Perhaps most notable is the use of certain Cannabis strains for their psychoactive effects. More recently, several biologically active molecules within the plants of these Cannabis strains, called phytocannabinoids or simply cannabinoids, have been identified. Furthermore, within human cells, endogenous cannabinoids, or endocannabinoids, as well as the receptors and secondary messengers that give rise to their neuromodulatory effects, have also been characterized. This endocannabinoid system (ECS) is composed of two primary ligands-anandamide and 2-arachidonyl glycerol; two primary receptors-cannabinoid receptors 1 and 2; and several enzymes involved in biosynthesis and degradation of endocannabinoid ligands including diacylglycerol lipase (DAGL) and monoacylglycerol lipase (MAGL). Here we briefly summarize cannabinoid signaling and review what has been discerned to date with regard to cannabinoid signaling in the auditory system and its roles in normal physiological function as well as pathological conditions. While much has been uncovered regarding cannabinoid signaling in the central nervous system, less attention has been paid to the auditory system specifically. Still, evidence is emerging to suggest that cannabinoid signaling is critical for the development, maturation, function, and survival of cochlear hair cells (HCs) and spiral ganglion neurons (SGNs). Furthermore, cannabinoid signaling can have profound effects on synaptic connectivity in CNS structures related to auditory processing. While clinical cases demonstrate that endogenous and exogenous cannabinoids impact auditory function, this review highlights several areas, such as SGN development, where more research is warranted.
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Affiliation(s)
- Sumana Ghosh
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, United States
| | - Kendra Stansak
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, United States
| | - Bradley J Walters
- Department of Neurobiology and Anatomical Sciences, University of Mississippi Medical Center, Jackson, MS, United States.,Department of Otolaryngology-Head and Neck Surgery, University of Mississippi Medical Center, Jackson, MS, United States
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Azuma YT, Suzuki S, Nishiyama K, Yamaguchi T. Gastrointestinal motility modulation by stress is associated with reduced smooth muscle contraction through specific transient receptor potential channel. J Vet Med Sci 2021; 83:622-629. [PMID: 33583865 PMCID: PMC8111361 DOI: 10.1292/jvms.20-0490] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
Excessive stress response causes disability in social life. There are many diseases
caused by stress, such as gastrointestinal motility disorders, depression, eating
disorders, and cardiovascular diseases. Transient receptor potential (TRP) channels
underlie non-selective cation currents and are downstream effectors of G protein-coupled
receptors. Ca2+ influx is important for smooth muscle contraction, which is
responsible for gastrointestinal motility. Little is known about the possible involvement
of TRP channels in the gastrointestinal motility disorders due to stress. The purpose of
this study was to measure the changes in gastrointestinal motility caused by stress and to
elucidate the mechanism of these changes. The stress model used the water immersion
restraint stress. Gastrointestinal motility, especially the ileum, was recorded responses
to electric field stimulation (EFS) by isometric transducer. EFS-induced contraction was
significantly reduced in the ileum of stressed mouse. Even under the conditions treated
with atropine, EFS-induced contraction was significantly reduced in the ileum of stressed
mouse. In addition, carbachol-induced, neurokinin A-induced, and substance P-induced
contractions were all significantly reduced in the ileum of stressed mouse. Furthermore,
the expression of TRPC3 was decreased in the ileum of stressed mouse. These results
suggest that the gastrointestinal motility disorders due to stress is associated with
specific non-selective cation channel.
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Affiliation(s)
- Yasu-Taka Azuma
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Sciences, Izumisano, Osaka 598-8531, Japan
| | - Sho Suzuki
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Sciences, Izumisano, Osaka 598-8531, Japan
| | - Kazuhiro Nishiyama
- Laboratory of Veterinary Pharmacology, Division of Veterinary Science, Osaka Prefecture University Graduate School of Life and Environmental Sciences, Izumisano, Osaka 598-8531, Japan
| | - Taro Yamaguchi
- Laboratory of Pharmacology, Faculty of Pharmaceutical Sciences, Setsunan University, Hirakata, Osaka 573-0101, Japan
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Ashmore J. Tonotopy of cochlear hair cell biophysics (excl. mechanotransduction). CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2020.06.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Cochlear homeostasis: a molecular physiological perspective on maintenance of sound transduction and auditory neurotransmission with noise and ageing. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2020.09.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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Wang S, Geng Q, Huo L, Ma Y, Gao Y, Zhang W, Zhang H, Lv P, Jia Z. Transient Receptor Potential Cation Channel Subfamily Vanilloid 4 and 3 in the Inner Ear Protect Hearing in Mice. Front Mol Neurosci 2019; 12:296. [PMID: 31866822 PMCID: PMC6904345 DOI: 10.3389/fnmol.2019.00296] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2019] [Accepted: 11/20/2019] [Indexed: 01/02/2023] Open
Abstract
The transient receptor potential cation channel, vanilloid type (TRPV) 3, is a member of the TRPV subfamily that is expressed predominantly in the skin, hair follicles, and gastrointestinal tract. It is also distributed in the organ of Corti of the inner ear and colocalizes with TRPV1 or TRPV4, but its role in auditory function is unknown. In the present study, we demonstrate that TRPV3 is expressed in inner hair cells (HCs) but mainly in cochlear outer HCs in mice, with expression limited to the cytoplasm and not detected in stereocilia. We compared the number of HCs as well as distortion product otoacoustic emissions (DPOAE) and auditory brainstem response (ABR) thresholds between TRPV3 knockout (V3KO) and wild-type (V3WT) mice and found that although most mutants (72.3%) had normal hearing, a significant proportion (27.7%) showed impaired hearing associated with loss of cochlear HCs. Compensatory upregulation of TRPV4 in HCs prevented HC damage and kanamycin-induced hearing loss and preserved normal auditory function in most of these mice. Thus, TRPV4 and TRPV3 in cochlear HCs protect hearing in mice; moreover, the results suggest some functional redundancy in the functions of TRPV family members. Our findings provide novel insight into the molecular basis of auditory function in mammals that can be applied to the development of strategies to mitigate hearing loss.
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Affiliation(s)
- Shengnan Wang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Qiaowei Geng
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Lifang Huo
- Department of Pharmacology, Institute of Chinese Integrative Medicine, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China
| | - Yirui Ma
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Yiting Gao
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Wei Zhang
- Department of Pharmacology, Institute of Chinese Integrative Medicine, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China
| | - Hailin Zhang
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Ping Lv
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
| | - Zhanfeng Jia
- Department of Pharmacology, Hebei Medical University, Shijiazhuang, China.,Center for Innovative Drug Research and Evaluation, Institute of Medical Science and Health, Hebei Medical University, Shijiazhuang, China.,The Key Laboratory of Neural and Vascular Biology, Ministry of Education, Shijiazhuang, China.,The Key Laboratory of New Drug Pharmacology and Toxicology, Shijiazhuang, China
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Berekméri E, Deák O, Téglás T, Sághy É, Horváth T, Aller M, Fekete Á, Köles L, Zelles T. Targeted single-cell electroporation loading of Ca 2+ indicators in the mature hemicochlea preparation. Hear Res 2018; 371:75-86. [PMID: 30504093 DOI: 10.1016/j.heares.2018.11.004] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/05/2018] [Revised: 10/30/2018] [Accepted: 11/07/2018] [Indexed: 10/27/2022]
Abstract
Ca2+ is an important intracellular messenger and regulator in both physiological and pathophysiological mechanisms in the hearing organ. Investigation of cellular Ca2+ homeostasis in the mature cochlea is hampered by the special anatomy and high vulnerability of the organ. A quick, straightforward and reliable Ca2+ imaging method with high spatial and temporal resolution in the mature organ of Corti is missing. Cell cultures or isolated cells do not preserve the special microenvironment and intercellular communication, while cochlear explants are excised from only a restricted portion of the organ of Corti and usually from neonatal pre-hearing murines. The hemicochlea, prepared from hearing mice allows tonotopic experimental approach on the radial perspective in the basal, middle and apical turns of the organ. We used the preparation recently for functional imaging in supporting cells of the organ of Corti after bulk loading of the Ca2+ indicator. However, bulk loading takes long time, is variable and non-selective, and causes the accumulation of the indicator in the extracellular space. In this study we show the improved labeling of supporting cells of the organ of Corti by targeted single-cell electroporation in mature mouse hemicochlea. Single-cell electroporation proved to be a reliable way of reducing the duration and variability of loading and allowed subcellular Ca2+ imaging by increasing the signal-to-noise ratio, while cell viability was retained during the experiments. We demonstrated the applicability of the method by measuring the effect of purinergic, TRPA1, TRPV1 and ACh receptor stimulation on intracellular Ca2+ concentration at the cellular and subcellular level. In agreement with previous results, ATP evoked reversible and repeatable Ca2+ transients in Deiters', Hensen's and Claudius' cells. TRPA1 and TRPV1 stimulation by AITC and capsaicin, respectively, failed to induce any Ca2+ response in the supporting cells, except in a single Hensen's cell in which AITC evoked transients with smaller amplitude. AITC also caused the displacement of the tissue. Carbachol, agonist of ACh receptors induced Ca2+ transients in about a third of Deiters' and fifth of Hensen's cells. Here we have presented a fast and cell-specific indicator loading method allowing subcellular functional Ca2+ imaging in supporting cells of the organ of Corti in the mature hemicochlea preparation, thus providing a straightforward tool for deciphering the poorly understood regulation of Ca2+ homeostasis in these cells.
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Affiliation(s)
- Eszter Berekméri
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Orsolya Deák
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Tímea Téglás
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Éva Sághy
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Tamás Horváth
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Máté Aller
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Ádám Fekete
- Program in Neurosciences and Mental Health, The Hospital for Sick Children, Toronto, ON, Canada
| | - László Köles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary
| | - Tibor Zelles
- Department of Pharmacology and Pharmacotherapy, Semmelweis University, Budapest, Hungary.
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14
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Asai Y, Pan B, Nist-Lund C, Galvin A, Lukashkin AN, Lukashkina VA, Chen T, Zhou W, Zhu H, Russell IJ, Holt JR, Géléoc GSG. Transgenic Tmc2 expression preserves inner ear hair cells and vestibular function in mice lacking Tmc1. Sci Rep 2018; 8:12124. [PMID: 30108254 PMCID: PMC6092434 DOI: 10.1038/s41598-018-28958-x] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2018] [Accepted: 07/03/2018] [Indexed: 01/18/2023] Open
Abstract
Recent work has demonstrated that transmembrane channel-like 1 protein (TMC1) is an essential component of the sensory transduction complex in hair cells of the inner ear. A closely related homolog, TMC2, is expressed transiently in the neonatal mouse cochlea and can enable sensory transduction in Tmc1-null mice during the first postnatal week. Both TMC1 and TMC2 are expressed at adult stages in mouse vestibular hair cells. The extent to which TMC1 and TMC2 can substitute for each other is unknown. Several biophysical differences between TMC1 and TMC2 suggest these proteins perform similar but not identical functions. To investigate these differences, and whether TMC2 can substitute for TMC1 in mature hair cells, we generated a knock-in mouse model allowing Cre-inducible expression of Tmc2. We assayed for changes in hair cell sensory transduction and auditory and vestibular function in Tmc2 knockin mice (Tm[Tmc2]) in the presence or absence of endogenous Tmc1, Tmc2 or both. Our results show that expression of Tm[TMC2] restores sensory transduction in vestibular hair cells and transiently in cochlear hair cells in the absence of TMC1. The cellular rescue leads to recovery of balance but not auditory function. We conclude that TMC1 provides some additional necessary function, not provided by TMC2.
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Affiliation(s)
- Yukako Asai
- Department of Otolaryngology and Communication Enhancement, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Bifeng Pan
- Department of Otolaryngology and Communication Enhancement, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Carl Nist-Lund
- Department of Otolaryngology and Communication Enhancement, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Alice Galvin
- Department of Otolaryngology and Communication Enhancement, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Andrei N Lukashkin
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK
| | - Victoria A Lukashkina
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK
| | - Tianwen Chen
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Oxford, MS, USA
| | - Wu Zhou
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Oxford, MS, USA
| | - Hong Zhu
- Department of Otolaryngology and Communicative Sciences, University of Mississippi Medical Center, Oxford, MS, USA
| | - Ian J Russell
- Sensory Neuroscience Research Group, School of Pharmacy and Biomolecular Sciences, University of Brighton, Brighton, UK
| | - Jeffrey R Holt
- Department of Otolaryngology and Communication Enhancement, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
- Department of Neurology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Gwenaelle S G Géléoc
- Department of Otolaryngology and Communication Enhancement, F.M. Kirby Center for Neurobiology, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA.
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15
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Morgan CP, Zhao H, LeMasurier M, Xiong W, Pan B, Kazmierczak P, Avenarius MR, Bateschell M, Larisch R, Ricci AJ, Müller U, Barr-Gillespie PG. TRPV6, TRPM6 and TRPM7 Do Not Contribute to Hair-Cell Mechanotransduction. Front Cell Neurosci 2018; 12:41. [PMID: 29515374 PMCID: PMC5826258 DOI: 10.3389/fncel.2018.00041] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2017] [Accepted: 02/01/2018] [Indexed: 12/02/2022] Open
Abstract
Hair cells of the inner ear transduce mechanical stimuli like sound or head movements into electrical signals, which are propagated to the central nervous system. The hair-cell mechanotransduction channel remains unidentified. We tested whether three transient receptor channel (TRP) family members, TRPV6, TRPM6 and TRPM7, were necessary for transduction. TRPV6 interacted with USH1C (harmonin), a scaffolding protein that participates in transduction. Using a cysteine-substitution knock-in mouse line and methanethiosulfonate (MTS) reagents selective for this allele, we found that inhibition of TRPV6 had no effect on transduction in mouse cochlear hair cells. TRPM6 and TRPM7 each interacted with the tip-link component PCDH15 in cultured eukaryotic cells, which suggested they might be part of the transduction complex. Cochlear hair cell transduction was not affected by manipulations of Mg2+, however, which normally perturbs TRPM6 and TRPM7. To definitively examine the role of these two channels in transduction, we showed that deletion of either or both of their genes selectively in hair cells had no effect on auditory function. We suggest that TRPV6, TRPM6 and TRPM7 are unlikely to be the pore-forming subunit of the hair-cell transduction channel.
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Affiliation(s)
- Clive P. Morgan
- Oregon Hearing Research Center & Vollum Institute, Oregon Health & Science University, Portland, OR, United States
| | - Hongyu Zhao
- Oregon Hearing Research Center & Vollum Institute, Oregon Health & Science University, Portland, OR, United States
| | - Meredith LeMasurier
- Oregon Hearing Research Center & Vollum Institute, Oregon Health & Science University, Portland, OR, United States
| | - Wei Xiong
- Department of Neuroscience, Scripps Research Institute, La Jolla, CA, United States
| | - Bifeng Pan
- Department of Otolaryngology, Stanford University, Stanford, CA, United States
| | - Piotr Kazmierczak
- Department of Neuroscience, Scripps Research Institute, La Jolla, CA, United States
| | - Matthew R. Avenarius
- Oregon Hearing Research Center & Vollum Institute, Oregon Health & Science University, Portland, OR, United States
| | - Michael Bateschell
- Oregon Hearing Research Center & Vollum Institute, Oregon Health & Science University, Portland, OR, United States
| | - Ruby Larisch
- Oregon Hearing Research Center & Vollum Institute, Oregon Health & Science University, Portland, OR, United States
| | - Anthony J. Ricci
- Department of Otolaryngology, Stanford University, Stanford, CA, United States
| | - Ulrich Müller
- Department of Neuroscience, Scripps Research Institute, La Jolla, CA, United States
| | - Peter G. Barr-Gillespie
- Oregon Hearing Research Center & Vollum Institute, Oregon Health & Science University, Portland, OR, United States
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16
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Sheth S, Mukherjea D, Rybak LP, Ramkumar V. Mechanisms of Cisplatin-Induced Ototoxicity and Otoprotection. Front Cell Neurosci 2017; 11:338. [PMID: 29163050 PMCID: PMC5663723 DOI: 10.3389/fncel.2017.00338] [Citation(s) in RCA: 221] [Impact Index Per Article: 31.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2017] [Accepted: 10/12/2017] [Indexed: 12/20/2022] Open
Abstract
Evidence of significant hearing loss during the early days of use of cisplatin as a chemotherapeutic agent in cancer patients has stimulated research into the causes and treatment of this side effect. It has generally been accepted that hearing loss is produced by excessive generation of reactive oxygen species (ROS) in cell of the cochlea, which led to the development of various antioxidants as otoprotective agents. Later studies show that ROS could stimulate cochlear inflammation, suggesting the use of anti-inflammatory agents for treatment of hearing loss. In this respect, G-protein coupled receptors, such as adenosine A1 receptor and cannabinoid 2 receptors, have shown efficacy in the treatment of hearing loss in experimental animals by increasing ROS scavenging, suppressing ROS generation, or by decreasing inflammation. Inflammation could be triggered by activation of transient receptor potential vanilloid 1 (TRPV1) channels in the cochlea and possibly other TRP channels. Targeting TRPV1 for knockdown has also been shown to be a useful strategy for ensuring otoprotection. Cisplatin entry into cochlear hair cells is mediated by various transporters, inhibitors of which have been shown to be effective for treating hearing loss. Finally, cisplatin-induced DNA damage and activation of the apoptotic process could be targeted for cisplatin-induced hearing loss. This review focuses on recent development in our understanding of the mechanisms underlying cisplatin-induced hearing loss and provides examples of how drug therapies have been formulated based on these mechanisms.
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Affiliation(s)
- Sandeep Sheth
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Debashree Mukherjea
- Department of Surgery (Otolaryngology), Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Leonard P Rybak
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States.,Department of Surgery (Otolaryngology), Southern Illinois University School of Medicine, Springfield, IL, United States
| | - Vickram Ramkumar
- Department of Pharmacology, Southern Illinois University School of Medicine, Springfield, IL, United States
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17
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Majumder P, Moore PA, Richardson GP, Gale JE. Protecting Mammalian Hair Cells from Aminoglycoside-Toxicity: Assessing Phenoxybenzamine's Potential. Front Cell Neurosci 2017; 11:94. [PMID: 28503132 PMCID: PMC5408764 DOI: 10.3389/fncel.2017.00094] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Accepted: 03/20/2017] [Indexed: 11/26/2022] Open
Abstract
Aminoglycosides (AGs) are widely used antibiotics because of their low cost and high efficacy against gram-negative bacterial infection. However, AGs are ototoxic, causing the death of sensory hair cells in the inner ear. Strategies aimed at developing or discovering agents that protect against aminoglycoside ototoxicity have focused on inhibiting apoptosis or more recently, on preventing antibiotic uptake by the hair cells. Recent screens for ototoprotective compounds using the larval zebrafish lateral line identified phenoxybenzamine as a potential protectant for aminoglycoside-induced hair cell death. Here we used live imaging of FM1-43 uptake as a proxy for aminoglycoside entry, combined with hair-cell death assays to evaluate whether phenoxybenzamine can protect mammalian cochlear hair cells from the deleterious effects of the aminoglycoside antibiotic neomycin. We show that phenoxybenzamine can block FM1-43 entry into mammalian hair cells in a reversible and dose-dependent manner, but pre-incubation is required for maximal inhibition of entry. We observed differential effects of phenoxybenzamine on FM1-43 uptake in the two different types of cochlear hair cell in mammals, the outer hair cells (OHCs) and inner hair cells (IHCs). The requirement for pre-incubation and reversibility suggests an intracellular rather than an extracellular site of action for phenoxybenzamine. We also tested the efficacy of phenoxybenzamine as an otoprotective agent. In mouse cochlear explants the hair cell death resulting from 24 h exposure to neomycin was steeply dose-dependent, with 50% cell death occurring at ~230 μM for both IHC and OHC. We used 250 μM neomycin in subsequent hair-cell death assays. At 100 μM with 1 h pre-incubation, phenoxybenzamine conferred significant protection to both IHCs and OHCs, however at higher concentrations phenoxybenzamine itself showed clear signs of ototoxicity and an additive toxic effect when combined with neomycin. These data do not support the use of phenoxybenzamine as a therapeutic agent in mammalian inner ear. Our findings do share parallels with the observations from the zebrafish lateral line model but they also highlight the necessity for validation in the mammalian system and the potential for differential effects on sensory hair cells from different species, in different systems and even between cells in the same organ.
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Affiliation(s)
| | | | - Guy P Richardson
- Sussex Neuroscience, School of Life Sciences, University of SussexFalmer, UK
| | - Jonathan E Gale
- UCL Ear Institute, University College LondonLondon, UK.,Department of Cell and Developmental Biology, University College LondonLondon, UK
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18
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Wu X, Indzhykulian AA, Niksch PD, Webber RM, Garcia-Gonzalez M, Watnick T, Zhou J, Vollrath MA, Corey DP. Hair-Cell Mechanotransduction Persists in TRP Channel Knockout Mice. PLoS One 2016; 11:e0155577. [PMID: 27196058 PMCID: PMC4873267 DOI: 10.1371/journal.pone.0155577] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/04/2016] [Accepted: 05/01/2016] [Indexed: 12/17/2022] Open
Abstract
Members of the TRP superfamily of ion channels mediate mechanosensation in some organisms, and have been suggested as candidates for the mechanotransduction channel in vertebrate hair cells. Some TRP channels can be ruled out based on lack of an inner ear phenotype in knockout animals or pore properties not similar to the hair-cell channel. Such studies have excluded Trpv4, Trpa1, Trpml3, Trpm1, Trpm3, Trpc1, Trpc3, Trpc5, and Trpc6. However, others remain reasonable candidates. We used data from an RNA-seq analysis of gene expression in hair cells as well as data on TRP channel conductance to narrow the candidate group. We then characterized mice lacking functional Trpm2, Pkd2, Pkd2l1, Pkd2l2 and Pkd1l3, using scanning electron microscopy, auditory brainstem response, permeant dye accumulation, and single-cell electrophysiology. In all of these TRP-deficient mice, and in double and triple knockouts, mechanotransduction persisted. Together with published studies, these results argue against the participation of any of the 33 mouse TRP channels in hair cell transduction.
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MESH Headings
- Animals
- Calcium Channels/genetics
- Cochlea/physiology
- Ear, Inner/physiology
- Evoked Potentials, Auditory, Brain Stem/genetics
- Gene Expression Profiling
- Gene Expression Regulation
- Hair Cells, Auditory/physiology
- Hearing
- Mechanotransduction, Cellular
- Membrane Glycoproteins/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Microscopy, Electron, Scanning
- Patch-Clamp Techniques
- Receptors, Cell Surface/genetics
- TRPM Cation Channels/genetics
- TRPP Cation Channels/genetics
- Transient Receptor Potential Channels/genetics
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Affiliation(s)
- Xudong Wu
- Department of Neurobiology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Artur A. Indzhykulian
- Department of Neurobiology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Paul D. Niksch
- Department of Neurobiology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Roxanna M. Webber
- Department of Neurobiology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
| | - Miguel Garcia-Gonzalez
- Department of Medicine, Division of Nephrology, University of Maryland, Baltimore, Maryland, United States of America
| | - Terry Watnick
- Department of Medicine, Division of Nephrology, University of Maryland, Baltimore, Maryland, United States of America
| | - Jing Zhou
- Renal Division, Department of Medicine, Brigham and Women's Hospital and Harvard Medical School, Boston, Massachusetts, United States of America
| | - Melissa A. Vollrath
- Department of Neurobiology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
- Department of Physiology, McGill University Montréal, Québec, Canada
| | - David P. Corey
- Department of Neurobiology, Harvard Medical School and Howard Hughes Medical Institute, Boston, Massachusetts, United States of America
- * E-mail:
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19
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Transient Receptor Potential Canonical 7 (TRPC7), a Calcium (Ca(2+)) Permeable Non-selective Cation Channel. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2016; 898:251-64. [PMID: 27161232 DOI: 10.1007/978-3-319-26974-0_11] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Transient receptor potential canonical subfamily, member 7 (TRPC7) is the most recently identified member of the TRPC family of Ca(2+)-permeable non-selective cation channels. The gene encoding the TRPC7 channel plasma membrane protein was first cloned from mouse brain. TRPC7 mRNA and protein have been detected in cell types derived from multiple organ systems from various species including humans. Gq-coupled protein receptor activation is the predominant mode of TRPC7 activation. Lipid metabolites involved in the phospholipase C (PLC) signaling pathway, including diacylglycerol (DAG) and its precursor the phosphatidylinositol-4,5-bisphosphate (PIP2), have been shown to be direct regulators of TRPC7 channel. TRPC7 channels have been linked to the regulation of various cellular functions however, the depth of our understanding of TRPC7 channel function and regulation is limited in comparison to other TRP channel family members. This review takes a historical look at our current knowledge of TRPC7 mechanisms of activation and its role in cellular physiology and pathophysiology.
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20
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Mori Y, Takahashi N, Polat OK, Kurokawa T, Takeda N, Inoue M. Redox-sensitive transient receptor potential channels in oxygen sensing and adaptation. Pflugers Arch 2015; 468:85-97. [PMID: 26149285 PMCID: PMC4700073 DOI: 10.1007/s00424-015-1716-2] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 06/22/2015] [Indexed: 12/14/2022]
Abstract
Regulation of ion channels is central to the mechanisms that underlie immediate acute physiological responses to changes in the availability of molecular oxygen (O2). A group of cation-permeable channels that are formed by transient receptor potential (TRP) proteins have been characterized as exquisite sensors of redox reactive species and as efficient actuators of electric/ionic signals in vivo. In this review, we first discuss how redox-sensitive TRP channels such as TRPA1 have recently emerged as sensors of the relatively inert oxidant O2. With regard to the physiological significance of O2 sensor TRP channels, vagal TRPA1 channels are mainly discussed with respect to their role in respiratory regulation in comparison with canonical pathways in glomus cells of the carotid body, which is a well-established O2-sensing organ. TRPM7 channels are discussed regarding hypoxia-sensing function in ischemic cell death. Also, ubiquitous expression of TRPA1 and TRPM7 together with their physiological relevance in the body is examined. Finally, based upon these studies on TRP channels, we propose a hypothesis of “O2 remodeling.” The hypothesis is that cells detect deviation of O2 availability from appropriate levels via sensors and adjust local O2 environments in vivo by controlling supply and consumption of O2 via pathways comprising cellular signals and transcription factors downstream of sensors, which consequently optimize physiological functions. This new insight into O2 adaptation through ion channels, particularly TRPs, may foster a paradigm shift in our understanding in the biological significance of O2.
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Affiliation(s)
- Yasuo Mori
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
- Laboratory of Environmental Systems Biology, Department of Technology and Ecology, Hall of Global Environmental Studies, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan.
| | - Nobuaki Takahashi
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
- Department of Cell Biology, Harvard Medical School, Boston, MA, 02115, USA
| | - Onur Kerem Polat
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Tatsuki Kurokawa
- Laboratory of Molecular Biology, Department of Synthetic Chemistry and Biological Chemistry, Graduate School of Engineering, Kyoto University, Nishikyo-ku, Kyoto, 615-8510, Japan
| | - Norihiko Takeda
- Department of Cardiovascular Medicine, Graduate School of Medicine, The University of Tokyo, Bunkyo-ku, Tokyo, 113-8655, Japan
| | - Masahiro Inoue
- Department of Biochemistry, Osaka Medical Center for Cancer and Cardiovascular Diseases, Higashinari-ku, Osaka, 537-8511, Japan
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21
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Abstract
Transient receptor potential vanilloid 1 (TRPV1) channel has been found to be expressed in a variety of tissues over the last few years, including the central nervous system (CNS). However, the distribution of TRPV1 in the CNS remains a controversial question. Here, we reveal that the expression of TRPV1 can be detected in the C57BL/6 mouse hippocampus and cortex using real-time PCR and western blot. Beyond that, mRNA and protein expression levels of TRPV1 show dynamic changes during brain development. Compared with the earliest timepoint examined at 2 weeks, the expression levels of mRNA progressively increased at 4 and 8 weeks, peaking at the later timepoint, then declined at 16 weeks but remained elevated. However, compared with 2-week-old mice, the expression levels of the other three groups (4-, 8-, and 16-week-old mice) increased overall. These results indicate that TRPV1 channel expression is detectable in the CNS and it varies during postnatal development.
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22
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Effertz T, Scharr AL, Ricci AJ. The how and why of identifying the hair cell mechano-electrical transduction channel. Pflugers Arch 2014; 467:73-84. [PMID: 25241775 DOI: 10.1007/s00424-014-1606-z] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2014] [Revised: 08/28/2014] [Accepted: 09/01/2014] [Indexed: 01/10/2023]
Abstract
Identification of the auditory hair cell mechano-electrical transduction (hcMET) channel has been a major focus in the hearing research field since the 1980s when direct mechanical gating of a transduction channel was proposed (Corey and Hudspeth J Neurosci 3:962-976, 1983). To this day, the molecular identity of this channel remains controversial. However, many of the hcMET channel's properties have been characterized, including pore properties, calcium-dependent ion permeability, rectification, and single channel conductance. At this point, elucidating the molecular identity of the hcMET channel will provide new tools for understanding the mechanotransduction process. This review discusses the significance of identifying the hcMET channel, the difficulties associated with that task, as well as the establishment of clear criteria for this identification. Finally, we discuss potential candidate channels in light of these criteria.
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Affiliation(s)
- Thomas Effertz
- Department of Otolaryngology, School of Medicine, Stanford University, Stanford, CA, 94305, USA
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23
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Abstract
Hearing is a particularly sensitive form of mechanosensation that relies on dedicated ion channels transducing sound-induced vibrations that hardly exceed Brownian motion. Attempts to molecularly identify these auditory transduction channels have put the focus on TRPs in ears. In Drosophila, hearing has been shown to involve TRPA, TRPC, TRPN, and TRPV subfamily members, with candidate auditory transduction channels including NOMPC (=TRPN1) and the TRPVs Nan and Iav. In vertebrates, TRPs are unlikely to form auditory transduction channels, yet most TRPs are expressed in inner ear tissues, and mutations in TRPN1, TRPVA1, TRPML3, TRPV4, and TRPC3/TRPC6 have been implicated in inner ear function. Starting with a brief introduction of fly and vertebrate auditory anatomies and transduction mechanisms, this review summarizes our current understanding of the auditory roles of TRPs.
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Affiliation(s)
- Damiano Zanini
- Department of Cellular Neurobiology, University of Göttingen, Julia-Lermontowa-Weg 3, 37077, Göttingen, Germany
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24
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Abstract
Like most other members of the TRP family, the Trpm3 gene encodes proteins that form cation-permeable ion channels on the plasma membrane. However, TRPM3 proteins have several unique features that set them apart from the other members of this diverse family. The Trpm3 gene encodes for a surprisingly large number of isoforms generated mainly by alternative splicing. Only for two of the (at least) eight sites at which sequence diversity is generated the functional consequences have been elucidated, one leading to nonfunctional channels, the other one profoundly affecting the ionic selectivity. In the Trpm3 gene an intronic microRNA (miR-204) is co-transcribed with Trpm3. By regulating the expression of a multitude of genes, miR-204 increases the functional complexity of the Trpm3 locus. Over the past years, important progress has been made in discovering pharmacological tools to manipulate TRPM3 channel activity. These substances have facilitated the identification of endogenously expressed functional TRPM3 channels in nociceptive neurons, pancreatic beta cells, and vascular smooth muscle cells, among others. TRPM3 channels, which themselves are temperature sensitive, thus have been implicated in sensing noxious heat, in modulating insulin release, and in secretion of inflammatory cytokines. However, in many tissues where TRPM3 proteins are known to be expressed, no functional role has been identified for these channels so far. Because of the availability of adequate pharmacological and genetic tools, it is expected that future investigations on TRPM3 channels will unravel important new aspects and functions of these channels.
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Affiliation(s)
- Johannes Oberwinkler
- Institut für Physiologie und Pathophysiologie, Philipps-Universität Marburg, 35037, Marburg, Germany,
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25
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Nilius B, Flockerzi V. What do we really know and what do we need to know: some controversies, perspectives, and surprises. Handb Exp Pharmacol 2014; 223:1239-80. [PMID: 24961986 DOI: 10.1007/978-3-319-05161-1_20] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
TRP channels comprise one of the most rapid growing research topics in ion channel research, in fields related to ion channels including channelopathies and translational medicine. We provide here a critical survey on our current knowledge of TRP channels and highlight some of the still open or controversial questions. This comprises questions related to evolution of TRP channels; biophysics, i.e., permeation; pore properties and gating; modulation; the still-elusive 3D structure; and channel subunits but also their role as general sensory channels and in human diseases. We will conclude that our knowledge on TRP channels is still at the very beginning of an exciting research journey.
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Affiliation(s)
- Bernd Nilius
- Department Cell Mol Medicine, Laboratory Ion Channel Research, KU Leuven, Campus Gasthuisberg, O&N 1, Herestraat 49-Bus 802, 3000, Leuven, Belgium,
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Zhang X, Trebak M. Transient receptor potential canonical 7: a diacylglycerol-activated non-selective cation channel. Handb Exp Pharmacol 2014; 222:189-204. [PMID: 24756707 DOI: 10.1007/978-3-642-54215-2_8] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Transient receptor potential canonical 7 (TRPC7) channel is the seventh member of the mammalian TRPC channel family. TRPC7 mRNA, protein, and channel activity have been detected in many tissues and organs from the mouse, rat, and human. TRPC7 has high sequence homology with TRPC3 and TRPC6, and all three channels are activated by membrane receptors that couple to isoforms of phospholipase C (PLC) and mediate non-selective cation currents. TRPC7, along with TRPC3 and TRPC6, can be activated by direct exogenous application of diacylglycerol (DAG) analogues and by pharmacological maneuvers that increase endogenous DAG in cells. TRPC7 shows distinct properties of activation, such as constitutive activity and susceptibility to negative regulation by extracellular Ca(2+) and by protein kinase C. TRPC7 can form heteromultimers with TRPC3 and TRPC6. Although TRPC7 remains one of the least studied TRPC channel, its role in various cell types and physiological and pathophysiological conditions is beginning to emerge.
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Affiliation(s)
- Xuexin Zhang
- Nanobioscience Constellation, The State University of New York (SUNY), College of Nanoscale Science and Engineering (CNSE), 257 Fuller Road, Albany, NY, 12203, USA
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Wong ACY, Birnbaumer L, Housley GD. Canonical transient receptor potential channel subtype 3-mediated hair cell Ca2+entry regulates sound transduction and auditory neurotransmission. Eur J Neurosci 2013; 37:1478-86. [DOI: 10.1111/ejn.12158] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2012] [Revised: 01/09/2013] [Accepted: 01/16/2013] [Indexed: 12/20/2022]
Affiliation(s)
- Ann Chi Yan Wong
- Translational Neuroscience Facility and Department of Physiology; School of Medical Sciences; University of New South Wales; Sydney; 2052; NSW; Australia
| | - Lutz Birnbaumer
- Laboratory of Neurobiology, National Institute of Environmental Health Sciences, NIH, Building 101, Room F180, 111 TW Alexander Dr; Research Triangle Park; NC 27709; USA
| | - Gary D. Housley
- Translational Neuroscience Facility and Department of Physiology; School of Medical Sciences; University of New South Wales; Sydney; 2052; NSW; Australia
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Son EJ, Wu L, Yoon H, Kim S, Choi JY, Bok J. Developmental gene expression profiling along the tonotopic axis of the mouse cochlea. PLoS One 2012; 7:e40735. [PMID: 22808246 PMCID: PMC3395647 DOI: 10.1371/journal.pone.0040735] [Citation(s) in RCA: 32] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2011] [Accepted: 06/12/2012] [Indexed: 12/13/2022] Open
Abstract
The mammalian cochlear duct is tonotopically organized such that the basal cochlea is tuned to high frequency sounds and the apical cochlea to low frequency sounds. In an effort to understand how this tonotopic organization is established, we searched for genes that are differentially expressed along the tonotopic axis during neonatal development. Cochlear tissues dissected from P0 and P8 mice were divided into three equal pieces, representing the base, middle and apex, and gene expression profiles were determined using the microarray technique. The gene expression profiles were grouped according to changes in expression levels along the tonotopic axis as well as changes during neonatal development. The classified groups were further analyzed by functional annotation clustering analysis to determine whether genes associated with specific biological function or processes are particularly enriched in each group. These analyses identified several candidate genes that may be involved in cochlear development and acquisition of tonotopy. We examined the expression domains for a few candidate genes in the developing mouse cochlea. Tnc (tenacin C) and Nov (nephroblastoma overexpressed gene) are expressed in the basilar membrane, with increased expression toward the apex, which may contribute to graded changes in the structure of the basilar membrane along the tonotopic axis. In addition, Fst (Follistatin), an antagonist of TGF-β/BMP signaling, is expressed in the lesser epithelial ridge and at gradually higher levels towards the apex. The graded expression pattern of Fst is established at the time of cochlear specification and maintained throughout embryonic and postnatal development, suggesting its possible role in the organization of tonotopy. Our data will provide a good resource for investigating the developmental mechanisms of the mammalian cochlea including the acquisition of tonotopy.
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Affiliation(s)
- Eun Jin Son
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
- * E-mail: (JB); (EJS)
| | - Ling Wu
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Korea
- BK21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Heejei Yoon
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Korea
| | - Sunhee Kim
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Korea
| | - Jae Young Choi
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
- BK21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
| | - Jinwoong Bok
- Department of Otorhinolaryngology, Yonsei University College of Medicine, Seoul, Korea
- Department of Anatomy, Yonsei University College of Medicine, Seoul, Korea
- BK21 Project for Medical Science, Yonsei University College of Medicine, Seoul, Korea
- * E-mail: (JB); (EJS)
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TRPV4 axonal neuropathy spectrum disorder. J Clin Neurosci 2012; 19:927-33. [DOI: 10.1016/j.jocn.2011.12.003] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2011] [Accepted: 12/18/2011] [Indexed: 11/21/2022]
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30
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Kawashima Y, Géléoc GSG, Kurima K, Labay V, Lelli A, Asai Y, Makishima T, Wu DK, Della Santina CC, Holt JR, Griffith AJ. Mechanotransduction in mouse inner ear hair cells requires transmembrane channel-like genes. J Clin Invest 2011; 121:4796-809. [PMID: 22105175 DOI: 10.1172/jci60405] [Citation(s) in RCA: 301] [Impact Index Per Article: 23.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2011] [Accepted: 10/19/2011] [Indexed: 01/22/2023] Open
Abstract
Inner ear hair cells convert the mechanical stimuli of sound, gravity, and head movement into electrical signals. This mechanotransduction process is initiated by opening of cation channels near the tips of hair cell stereocilia. Since the identity of these ion channels is unknown, and mutations in the gene encoding transmembrane channel-like 1 (TMC1) cause hearing loss without vestibular dysfunction in both mice and humans, we investigated the contribution of Tmc1 and the closely related Tmc2 to mechanotransduction in mice. We found that Tmc1 and Tmc2 were expressed in mouse vestibular and cochlear hair cells and that GFP-tagged TMC proteins localized near stereocilia tips. Tmc2 expression was transient in early postnatal mouse cochlear hair cells but persisted in vestibular hair cells. While mice with a targeted deletion of Tmc1 (Tmc1(Δ) mice) were deaf and those with a deletion of Tmc2 (Tmc2(Δ) mice) were phenotypically normal, Tmc1(Δ)Tmc2(Δ) mice had profound vestibular dysfunction, deafness, and structurally normal hair cells that lacked all mechanotransduction activity. Expression of either exogenous TMC1 or TMC2 rescued mechanotransduction in Tmc1(Δ)Tmc2(Δ) mutant hair cells. Our results indicate that TMC1 and TMC2 are necessary for hair cell mechanotransduction and may be integral components of the mechanotransduction complex. Our data also suggest that persistent TMC2 expression in vestibular hair cells may preserve vestibular function in humans with hearing loss caused by TMC1 mutations.
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Affiliation(s)
- Yoshiyuki Kawashima
- Molecular Biology and Genetics Section, National Institute on Deafness and Other Communication Disorders, NIH, Rockville, Maryland 20850-3320, USA
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Mechanisms of aminoglycoside ototoxicity and targets of hair cell protection. Int J Otolaryngol 2011; 2011:937861. [PMID: 22121370 PMCID: PMC3202092 DOI: 10.1155/2011/937861] [Citation(s) in RCA: 255] [Impact Index Per Article: 19.6] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2011] [Accepted: 08/18/2011] [Indexed: 01/14/2023] Open
Abstract
Aminoglycosides are commonly prescribed antibiotics with deleterious side effects to the inner ear. Due to their popular application as a result of their potent antimicrobial activities, many efforts have been undertaken to prevent aminoglycoside ototoxicity. Over the years, understanding of the antimicrobial as well as ototoxic mechanisms of aminoglycosides has increased. These mechanisms are reviewed in regard to established and potential future targets of hair cell protection.
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Mahoney JL, Graugnard EM, Mire P, Watson GM. Evidence for involvement of TRPA1 in the detection of vibrations by hair bundle mechanoreceptors in sea anemones. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2011; 197:729-42. [PMID: 21394510 DOI: 10.1007/s00359-011-0636-7] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2010] [Revised: 02/15/2011] [Accepted: 02/15/2011] [Indexed: 10/18/2022]
Abstract
A homolog of TRPA1 was identified in the genome of the anemone, Nematostella vectensis (nv-TRPA1a), and predicted to possess six ankyrin repeat domains at the N-terminus and an ion channel domain near the C-terminus. Transmembrane segments of the ion channel domain are well conserved among several known TRPA1 polypeptides. Inhibitors of TRPA1 including ruthenium red decrease vibration-dependent discharge of nematocysts in N. vectensis and Haliplanella luciae. Activators of TRPA1 including URB-597 and polygodial increase nematocyst discharge in the absence of vibrations. Co-immunoprecipitation yields a band on SDS-PAGE gels at the predicted mass of the nv-TRPA1a polypeptide among other bands. Co-immunoprecipitation performed in the presence of antigenic peptide decreases the yield of this and several other polypeptides. In untreated controls, anti-nv-TRPA1a primarily labels the base of the hair bundle with some labeling also distributed along the length of stereocilia. Tissue immunolabeled in the presence of the antigenic peptide exhibits reduced labeling. Activating chemoreceptors for N-acetylated sugars induce immunolabel to distribute distally in stereocilia. In anemones, activating chemoreceptors for N-acetylated sugars induce hair bundles to elongate among several other structural and functional changes. Taken together, these results are consistent with the possibility that nv-TRPA1a participates in signal transduction of anemone hair bundles.
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Affiliation(s)
- Janna L Mahoney
- Department of Biology, University of Louisiana at Lafayette, USA
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Banke TG. The dilated TRPA1 channel pore state is blocked by amiloride and analogues. Brain Res 2011; 1381:21-30. [DOI: 10.1016/j.brainres.2011.01.021] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2010] [Revised: 12/30/2010] [Accepted: 01/08/2011] [Indexed: 10/18/2022]
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Phan PAB, Tadros SF, Kim Y, Birnbaumer L, Housley GD. Developmental regulation of TRPC3 ion channel expression in the mouse cochlea. Histochem Cell Biol 2010; 133:437-48. [PMID: 20229053 DOI: 10.1007/s00418-010-0686-x] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 02/28/2010] [Indexed: 02/07/2023]
Abstract
Canonical transient receptor potential type 3 (TRPC3) ion channels assemble from TRPC3 subunits and exhibit multiple activation mechanisms. TRPC3 has been proposed to contribute to Ca(2+) entry supporting Ca(2+) homeostasis in cochlear hair cells and to be activated by G protein-coupled receptor (GPCR) signaling in spiral ganglion neurons. The present study was designed to determine the spatiotemporal profile of TRPC3 expression during mouse cochlear ontogeny. TRPC3 immunofluorescence of cryosectioned cochleae was performed using E16-adult tissue. We found that prior to birth, TRPC3 expression was strongest in epithelial cells that form the cochlear partition. In the early postnatal period, to the onset of hearing (~P12), immunofluorescence was strongest in the hair cells, with increased expression in stria vascularis and Reissner's membrane. Afferent neurite labeling in inner spiral plexus and outer spiral bundles developed transiently in the perinatal period, corresponding to the critical period of synaptic consolidation, while signal in the spiral ganglion soma increased from the perinatal period through to adulthood. Compared with the late embryonic/early postnatal levels, hair cell expression was relatively weaker from the third postnatal week, whereas spiral ganglion soma labeling was stronger. In the adult, TRPC3 expression was primarily in the soma of spiral ganglion neurons, the hair cells, and the inner and outer sulcus regions. This spatiotemporal profile of TRPC3 expression was consistent with this ion channel contributing to development of sensory, neural and epithelial cochlear tissues, as well as hair cell Ca(2+) homeostasis and regulation of auditory neurotransmission via GPCR signaling.
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Affiliation(s)
- Patrick A B Phan
- Translational Neuroscience Facility, Department of Physiology, School of Medical Sciences, University of New South Wales, Wallace Wurth Building, UNSW Kensington Campus, Sydney, NSW, 2052, Australia
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