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Jing L, Liu K, Wang F, Su Y. Role of mechanically-sensitive cation channels Piezo1 and TRPV4 in trabecular meshwork cell mechanotransduction. Hum Cell 2024; 37:394-407. [PMID: 38316716 DOI: 10.1007/s13577-024-01035-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2023] [Accepted: 01/17/2024] [Indexed: 02/07/2024]
Abstract
Glaucoma is one of the leading causes of irreversible blindness in developed countries, and intraocular pressure (IOP) is primary and only treatable risk factor, suggesting that to a significant extent, glaucoma is a disease of IOP disorder and pathological mechanotransduction. IOP-lowering ways are limited to decreaseing aqueous humour (AH) production or increasing the uveoscleral outflow pathway. Still, therapeutic approaches have been lacking to control IOP by enhancing the trabecular meshwork (TM) pathway. Trabecular meshwork cells (TMCs) have endothelial and myofibroblast properties and are responsible for the renewal of the extracellular matrix (ECM). Mechanosensitive cation channels, including Piezo1 and TRPV4, are abundantly expressed in primary TMCs and trigger mechanostress-dependent ECM and cytoskeletal remodelling. However, prolonged mechanical stimulation severely affects cellular biosynthesis through TMC mechanotransduction, including signaling, gene expression, ECM remodelling, and cytoskeletal structural changes, involving outflow facilities and elevating IOP. As for the functional coupling relationship between Piezo1 and TRPV4 channels, inspired by VECs and osteoblasts, we hypothesized that Piezo1 may also act upstream of TRPV4 in glaucomatous TM tissue, mediating the activation of TRPV4 via Ca2+ inflow or Ca2+ binding to phospholipase A2(PLA2), and thus be involved in increasing TM outflow resistance and elevated IOP. Therefore, this review aims to help identify new potential targets for IOP stabilization in ocular hypertension and primary open-angle glaucoma by understanding the mechanical transduction mechanisms associated with the development of glaucoma and may provide ideas into novel treatments for preventing the progression of glaucoma by targeting mechanotransduction.
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Affiliation(s)
- Lingling Jing
- Department of Ophthalmology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Kexin Liu
- Department of Ophthalmology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Feng Wang
- Department of Ophthalmology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin, China.
| | - Ying Su
- Eye Hospital, The First Affiliated Hospital, Harbin Medical University, Harbin, China.
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2
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Zhang X, Wang F, Su Y. TRPV: An emerging target in glaucoma and optic nerve damage. Exp Eye Res 2024; 239:109784. [PMID: 38199261 DOI: 10.1016/j.exer.2024.109784] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/23/2023] [Revised: 11/30/2023] [Accepted: 01/06/2024] [Indexed: 01/12/2024]
Abstract
Transient receptor potential vanilloid (TRPV) channels are members of the TRP channel superfamily, which are ion channels that sense mechanical and osmotic stimuli and participate in Ca2+ signalling across the cell membrane. TRPV channels play important roles in maintaining the normal functions of an organism, and defects or abnormalities in TRPV channel function cause a range of diseases, including cardiovascular, neurological and urological disorders. Glaucoma is a group of chronic progressive optic nerve diseases with pathological changes that can occur in the tissues of the anterior and posterior segments of the eye, including the ciliary body, trabecular meshwork, Schlemm's canal, and retina. TRPV channels are expressed in these tissues and play various roles in glaucoma. In this article, we review various aspects of the pathogenesis of glaucoma, the structure and function of TRPV channels, the relationship between TRPV channels and systemic diseases, and the relationship between TRPV channels and ocular diseases, especially glaucoma, and we suggest future research directions. This information will help to further our understanding of TRPV channels and provide new ideas and targets for the treatment of glaucoma and optic nerve damage.
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Affiliation(s)
- Xiaotong Zhang
- Department of Ophthalmology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin, China
| | - Feng Wang
- Department of Ophthalmology, The Fourth Affiliated Hospital, Harbin Medical University, Harbin, China.
| | - Ying Su
- Eye Hospital, The First Affiliated Hospital, Harbin Medical University, Harbin, China.
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3
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Deal PE, Lee H, Mondal A, Lolicato M, de Mendonca PRF, Black H, El-Hilali X, Bryant C, Isacoff EY, Renslo AR, Minor DL. Development of covalent chemogenetic K 2P channel activators. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.15.561774. [PMID: 37905049 PMCID: PMC10614804 DOI: 10.1101/2023.10.15.561774] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/02/2023]
Abstract
K2P potassium channels regulate excitability by affecting cellular resting membrane potential in the brain, cardiovascular system, immune cells, and sensory organs. Despite their important roles in anesthesia, arrhythmia, pain, hypertension, sleep, and migraine, the ability to control K2P function remains limited. Here, we describe a chemogenetic strategy termed CATKLAMP (Covalent Activation of TREK family K+ channels to cLAmp Membrane Potential) that leverages the discovery of a site in the K2P modulator pocket that reacts with electrophile-bearing derivatives of a TREK subfamily small molecule activator, ML335, to activate the channel irreversibly. We show that the CATKLAMP strategy can be used to probe fundamental aspects of K2P function, as a switch to silence neuronal firing, and is applicable to all TREK subfamily members. Together, our findings exemplify a new means to alter K2P channel activity that should facilitate studies both molecular and systems level studies of K2P function and enable the search for new K2P modulators.
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Affiliation(s)
- Parker E. Deal
- Cardiovascular Research Institute, University of California, San Francisco, California 93858-2330 USA
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 93858-2330 USA
| | - Haerim Lee
- Cardiovascular Research Institute, University of California, San Francisco, California 93858-2330 USA
| | - Abhisek Mondal
- Cardiovascular Research Institute, University of California, San Francisco, California 93858-2330 USA
| | - Marco Lolicato
- Cardiovascular Research Institute, University of California, San Francisco, California 93858-2330 USA
| | | | - Holly Black
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, United States
| | - Xochina El-Hilali
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 93858-2330 USA
| | - Clifford Bryant
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 93858-2330 USA
| | - Ehud Y. Isacoff
- Department of Molecular and Cell Biology, University of California, Berkeley, Berkeley, California 94720, United States
- Helen Wills Neuroscience Institute, University of California, Berkeley, Berkeley, California 94720, United States
- Weill Neurohub, University of California, Berkeley, Berkeley, California 94720, United States
- Molecular Biophysics and Integrated Bio-imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
| | - Adam R. Renslo
- Department of Pharmaceutical Chemistry, University of California, San Francisco, California 93858-2330 USA
| | - Daniel L. Minor
- Cardiovascular Research Institute, University of California, San Francisco, California 93858-2330 USA
- Molecular Biophysics and Integrated Bio-imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720 USA
- Departments of Biochemistry and Biophysics, and Cellular and Molecular Pharmacology, University of California, San Francisco, California 93858-2330 USA
- California Institute for Quantitative Biomedical Research, University of California, San Francisco, California 93858-2330 USA
- Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, California 93858-2330 USA
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4
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Zhang Y, Liu Y, Sun J, Zhang W, Guo Z, Ma Q. Arachidonic acid metabolism in health and disease. MedComm (Beijing) 2023; 4:e363. [PMID: 37746665 PMCID: PMC10511835 DOI: 10.1002/mco2.363] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Revised: 08/13/2023] [Accepted: 08/17/2023] [Indexed: 09/26/2023] Open
Abstract
Arachidonic acid (AA), an n-6 essential fatty acid, is a major component of mammalian cells and can be released by phospholipase A2. Accumulating evidence indicates that AA plays essential biochemical roles, as it is the direct precursor of bioactive lipid metabolites of eicosanoids such as prostaglandins, leukotrienes, and epoxyeicosatrienoic acid obtained from three distinct enzymatic metabolic pathways: the cyclooxygenase pathway, lipoxygenase pathway, and cytochrome P450 pathway. AA metabolism is involved not only in cell differentiation, tissue development, and organ function but also in the progression of diseases, such as hepatic fibrosis, neurodegeneration, obesity, diabetes, and cancers. These eicosanoids are generally considered proinflammatory molecules, as they can trigger oxidative stress and stimulate the immune response. Therefore, interventions in AA metabolic pathways are effective ways to manage inflammatory-related diseases in the clinic. Currently, inhibitors targeting enzymes related to AA metabolic pathways are an important area of drug discovery. Moreover, many advances have also been made in clinical studies of AA metabolic inhibitors in combination with chemotherapy and immunotherapy. Herein, we review the discovery of AA and focus on AA metabolism in relation to health and diseases. Furthermore, inhibitors targeting AA metabolism are summarized, and potential clinical applications are discussed.
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Affiliation(s)
- Yiran Zhang
- Department of Orthopedic SurgeryOrthopedic Oncology InstituteThe Second Affiliated Hospital of Air Force Medical UniversityXi'anChina
| | - Yingxiang Liu
- Department of Orthopedic SurgeryOrthopedic Oncology InstituteThe Second Affiliated Hospital of Air Force Medical UniversityXi'anChina
| | - Jin Sun
- Department of Orthopedic SurgeryOrthopedic Oncology InstituteThe Second Affiliated Hospital of Air Force Medical UniversityXi'anChina
| | - Wei Zhang
- Department of PathologyThe Second Affiliated Hospital of Air Force Medical UniversityXi'anChina
| | - Zheng Guo
- Department of Orthopedic SurgeryOrthopedic Oncology InstituteThe Second Affiliated Hospital of Air Force Medical UniversityXi'anChina
| | - Qiong Ma
- Department of Orthopedic SurgeryOrthopedic Oncology InstituteThe Second Affiliated Hospital of Air Force Medical UniversityXi'anChina
- Department of PathologyThe Second Affiliated Hospital of Air Force Medical UniversityXi'anChina
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5
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Liu WW, Kinzy TG, Cooke Bailey JN, Xu Z, Hysi P, Wiggs JL. Mechanosensitive ion channel gene survey suggests potential roles in primary open angle glaucoma. Sci Rep 2023; 13:15871. [PMID: 37741866 PMCID: PMC10517927 DOI: 10.1038/s41598-023-43072-3] [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: 05/22/2023] [Accepted: 09/18/2023] [Indexed: 09/25/2023] Open
Abstract
Although glaucoma is a disease modulated by eye pressure, the mechanisms of pressure sensing in the eye are not well understood. Here, we investigated associations between mechanosensitive ion channel gene variants and primary open-angle glaucoma (POAG). Common (minor allele frequency > 5%) single nucleotide polymorphisms located within the genomic regions of 20 mechanosensitive ion channel genes in the K2P, TMEM63, PIEZO and TRP channel families were assessed using genotype data from the NEIGHBORHOOD consortium of 3853 cases and 33,480 controls. Rare (minor allele frequency < 1%) coding variants were assessed using exome array genotyping data for 2606 cases and 2606 controls. Association with POAG was analyzed using logistic regression adjusting for age and sex. Two rare PIEZO1 coding variants with protective effects were identified in the NEIGHBOR dataset: R1527H, (OR 0.17, P = 0.0018) and a variant that alters a canonical splice donor site, g.16-88737727-C-G Hg38 (OR 0.38, P = 0.02). Both variants showed similar effects in the UK Biobank and the R1527H also in the FinnGen database. Several common variants also reached study-specific thresholds for association in the NEIGHBORHOOD dataset. These results identify novel variants in several mechanosensitive channel genes that show associations with POAG, suggesting that these channels may be potential therapeutic targets.
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Affiliation(s)
- Wendy W Liu
- Spencer Center for Vision Research, Byers Eye Institute, Stanford University School of Medicine, 2370 Watson Court, Palo Alto, CA, 94303, USA.
| | - Tyler G Kinzy
- Department of Population and Quantitative Health Sciences, Cleveland Institute for Computational Biology, Case Western Reserve University, Cleveland, OH, USA
| | - Jessica N Cooke Bailey
- Department of Population and Quantitative Health Sciences, Cleveland Institute for Computational Biology, Case Western Reserve University, Cleveland, OH, USA
| | - Zihe Xu
- Department of Ophthalmology, King's College London, St. Thomas' Hospital, London, UK
| | - Pirro Hysi
- Department of Ophthalmology, King's College London, St. Thomas' Hospital, London, UK
- Department of Twin Research and Genetic Epidemiology, King's College London, St. Thomas' Hospital, London, UK
| | - Janey L Wiggs
- Massachusetts Eye and Ear, Harvard Medical School Boston, Boston, MA, USA
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6
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López-Cano JJ, González-Cela-Casamayor MA, Andrés-Guerrero V, Vicario-de-la-Torre M, Benítez-Del-Castillo JM, Herrero-Vanrell R, Molina-Martínez IT. New trends towards glaucoma treatment: Topical osmoprotective microemulsions loaded with latanoprost. Ocul Surf 2023; 29:314-330. [PMID: 37295473 DOI: 10.1016/j.jtos.2023.05.013] [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: 03/09/2023] [Revised: 05/29/2023] [Accepted: 05/30/2023] [Indexed: 06/12/2023]
Abstract
The chronic use of hypotensive agents eventually leads to ocular surface damage and poor patient compliance during glaucoma management. Thus, new sustained drug delivery systems are needed. This work aimed to develop osmoprotective latanoprost-loaded microemulsion formulations as new potential glaucoma treatments with ocular surface protective properties. The microemulsions were characterized and latanoprost encapsulation efficacy determined. In-vitro tolerance, osmoprotective efficacy, cell internalization as well as cell-microemulsion interactions and distribution were performed. In vivo hypotensive activity was conducted in rabbits to assess intraocular pressure reduction and relative ocular bioavailability. Physicochemical characterization showed nanodroplet sizes within 20-30 nm, being in vitro tolerance within 80 and 100% viability in corneal and conjunctival cells. Besides, microemulsions exhibited higher protection under hypertonic conditions than untreated cells. Cell fluorescence lasted for 11 days after short exposure to coumarin-loaded microemulsions (5 min) showing extensive internalization in different cell compartments by electronic microscopy. In vivo studies exhibited that a single instillation of latanoprost-loaded microemulsions reduced the intraocular pressure for several days (4-6 days without polymer and 9-13 days with polymers). Relative ocular bioavailability was 4.5 and 19 times higher than the marketed formulation. These findings suggest the use of these microemulsions as potential combined strategies for extended surface protection and glaucoma treatment.
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Affiliation(s)
- J J López-Cano
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Department of Pharmaceutics and Food Technology, School of Pharmacy (UCM), Plaza Ramón y Cajal s/n, Madrid, 28040, Spain; Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Health Research Institute of the San Carlos Clinical Hospital (IdISSC), Madrid, 28040, Spain
| | - M A González-Cela-Casamayor
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Department of Pharmaceutics and Food Technology, School of Pharmacy (UCM), Plaza Ramón y Cajal s/n, Madrid, 28040, Spain; Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Health Research Institute of the San Carlos Clinical Hospital (IdISSC), Madrid, 28040, Spain
| | - V Andrés-Guerrero
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Department of Pharmaceutics and Food Technology, School of Pharmacy (UCM), Plaza Ramón y Cajal s/n, Madrid, 28040, Spain; Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Health Research Institute of the San Carlos Clinical Hospital (IdISSC), Madrid, 28040, Spain
| | - M Vicario-de-la-Torre
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Department of Pharmaceutics and Food Technology, School of Pharmacy (UCM), Plaza Ramón y Cajal s/n, Madrid, 28040, Spain; Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Health Research Institute of the San Carlos Clinical Hospital (IdISSC), Madrid, 28040, Spain
| | - J M Benítez-Del-Castillo
- Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Health Research Institute of the San Carlos Clinical Hospital (IdISSC), Madrid, 28040, Spain; Ocular Surface and Inflammation Unit, Ophthalmology Department, Sanitary Research Institute of the San Carlos Clinical Hospital (IdISSC), Madrid, 28040, Spain
| | - R Herrero-Vanrell
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Department of Pharmaceutics and Food Technology, School of Pharmacy (UCM), Plaza Ramón y Cajal s/n, Madrid, 28040, Spain; Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Health Research Institute of the San Carlos Clinical Hospital (IdISSC), Madrid, 28040, Spain.
| | - I T Molina-Martínez
- Innovation, Therapy and Pharmaceutical Development in Ophthalmology (InnOftal) Research Group, UCM 920415, Department of Pharmaceutics and Food Technology, School of Pharmacy (UCM), Plaza Ramón y Cajal s/n, Madrid, 28040, Spain; Ocular Pathology National Net (OFTARED) of the Institute of Health Carlos III, Health Research Institute of the San Carlos Clinical Hospital (IdISSC), Madrid, 28040, Spain.
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7
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Unnithan AR, Rotherham M, Markides H, El Haj AJ. Magnetic Ion Channel Activation (MICA)-Enabled Screening Assay: A Dynamic Platform for Remote Activation of Mechanosensitive Ion Channels. Int J Mol Sci 2023; 24:ijms24043364. [PMID: 36834776 PMCID: PMC9962865 DOI: 10.3390/ijms24043364] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 02/02/2023] [Accepted: 02/04/2023] [Indexed: 02/10/2023] Open
Abstract
This study reports results of a mechanical platform-based screening assay (MICA) to evaluate the remote activation of mechanosensitive ion channels. Here, we studied ERK pathway activation and the elevation in intracellular Ca2+ levels in response to the MICA application using the Luciferase assay and Fluo-8AM assay, respectively. Functionalised magnetic nanoparticles (MNPs) targeting membrane-bound integrins and mechanosensitive TREK1 ion channels were studied with HEK293 cell lines under MICA application. The study demonstrated that active targeting of mechanosensitive integrins via RGD (Arginylglycylaspartic acid) motifs or TREK1 (KCNK2, potassium channel subfamily K member 2) ion channels can stimulate the ERK pathway and intracellular calcium levels compared to non-MICA controls. This screening assay offers a powerful tool, which aligns with existing high-throughput drug screening platforms for use in the assessment of drugs that interact with ion channels and influence ion channel-modulated diseases.
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Affiliation(s)
- Afeesh Rajan Unnithan
- Healthcare Technology Institute, Institute of Translational Medicine, University of Birmingham, Birmingham B15 2TH, UK
- Centre for Pharmaceutical Engineering Science, School of Pharmacy and Medical Sciences, Faculty of Lifesciences, University of Bradford, Bradford BD7 1DP, UK
- Correspondence: (A.R.U.); (A.J.E.H.)
| | - Michael Rotherham
- Healthcare Technology Institute, Institute of Translational Medicine, University of Birmingham, Birmingham B15 2TH, UK
| | - Hareklea Markides
- Healthcare Technology Institute, Institute of Translational Medicine, University of Birmingham, Birmingham B15 2TH, UK
| | - Alicia J. El Haj
- Healthcare Technology Institute, Institute of Translational Medicine, University of Birmingham, Birmingham B15 2TH, UK
- Correspondence: (A.R.U.); (A.J.E.H.)
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8
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Križaj D, Cordeiro S, Strauß O. Retinal TRP channels: Cell-type-specific regulators of retinal homeostasis and multimodal integration. Prog Retin Eye Res 2023; 92:101114. [PMID: 36163161 PMCID: PMC9897210 DOI: 10.1016/j.preteyeres.2022.101114] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/03/2022] [Accepted: 08/08/2022] [Indexed: 02/05/2023]
Abstract
Transient receptor potential (TRP) channels are a widely expressed family of 28 evolutionarily conserved cationic ion channels that operate as primary detectors of chemical and physical stimuli and secondary effectors of metabotropic and ionotropic receptors. In vertebrates, the channels are grouped into six related families: TRPC, TRPV, TRPM, TRPA, TRPML, and TRPP. As sensory transducers, TRP channels are ubiquitously expressed across the body and the CNS, mediating critical functions in mechanosensation, nociception, chemosensing, thermosensing, and phototransduction. This article surveys current knowledge about the expression and function of the TRP family in vertebrate retinas, which, while dedicated to transduction and transmission of visual information, are highly susceptible to non-visual stimuli. Every retinal cell expresses multiple TRP subunits, with recent evidence establishing their critical roles in paradigmatic aspects of vertebrate vision that include TRPM1-dependent transduction of ON bipolar signaling, TRPC6/7-mediated ganglion cell phototransduction, TRP/TRPL phototransduction in Drosophila and TRPV4-dependent osmoregulation, mechanotransduction, and regulation of inner and outer blood-retina barriers. TRP channels tune light-dependent and independent functions of retinal circuits by modulating the intracellular concentration of the 2nd messenger calcium, with emerging evidence implicating specific subunits in the pathogenesis of debilitating diseases such as glaucoma, ocular trauma, diabetic retinopathy, and ischemia. Elucidation of TRP channel involvement in retinal biology will yield rewards in terms of fundamental understanding of vertebrate vision and therapeutic targeting to treat diseases caused by channel dysfunction or over-activation.
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Affiliation(s)
- David Križaj
- Departments of Ophthalmology, Neurobiology, and Bioengineering, University of Utah, Salt Lake City, USA
| | - Soenke Cordeiro
- Institute of Physiology, Faculty of Medicine, Christian-Albrechts-University Kiel, Germany
| | - Olaf Strauß
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, a Corporate Member of Freie Universität, Humboldt-University, The Berlin Institute of Health, Berlin, Germany.
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9
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Shim MS, Liton PB. The physiological and pathophysiological roles of the autophagy lysosomal system in the conventional aqueous humor outflow pathway: More than cellular clean up. Prog Retin Eye Res 2022; 90:101064. [PMID: 35370083 PMCID: PMC9464695 DOI: 10.1016/j.preteyeres.2022.101064] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2021] [Revised: 03/09/2022] [Accepted: 03/25/2022] [Indexed: 10/18/2022]
Abstract
During the last few years, the autophagy lysosomal system is emerging as a central cellular pathway with roles in survival, acting as a housekeeper and stress response mechanism. Studies by our and other labs suggest that autophagy might play an essential role in maintaining aqueous humor outflow homeostasis, and that malfunction of autophagy in outflow pathway cells might predispose to ocular hypertension and glaucoma pathogenesis. In this review, we will collect the current knowledge and discuss the molecular mechanisms by which autophagy does or might regulate normal outflow pathway tissue function, and its response to different types of stressors (oxidative stress and mechanical stress). We will also discuss novel roles of autophagy and lysosomal enzymes in modulation of TGFβ signaling and ECM remodeling, and the link between dysregulated autophagy and cellular senescence. We will examine what we have learnt, using pre-clinical animal models about how dysregulated autophagy can contribute to disease and apply that to the current status of autophagy in human glaucoma. Finally, we will consider and discuss the challenges and the potential of autophagy as a therapeutic target for the treatment of ocular hypertension and glaucoma.
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Affiliation(s)
- Myoung Sup Shim
- Duke University, Department of Ophthalmology, Durham, NC, 27705, USA
| | - Paloma B Liton
- Duke University, Department of Ophthalmology, Durham, NC, 27705, USA.
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10
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Targeting ferroptosis in ischemia/reperfusion renal injury. Naunyn Schmiedebergs Arch Pharmacol 2022; 395:1331-1341. [PMID: 35920897 DOI: 10.1007/s00210-022-02277-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2022] [Accepted: 07/18/2022] [Indexed: 10/16/2022]
Abstract
Renal I/R injury is a severe medical condition contributing to acute kidney injury (AKI), leading to rapid kidney dysfunction and high mortality rates. It is generally observed during renal transplantation, shock, trauma, and urologic and cardiovascular surgery, for which there is no effective treatment. Cell death and damage are commonly linked to I/R. Cell death triggered by iron-dependent lipid peroxidation, such as ferroptosis, has been demonstrated to have a significant detrimental effect in renal IRI models, making it a new type of cell death currently being researched. Ferroptosis is a nonapoptotic type of cell death that occurs when free iron enters the cell and is a critical component of many biological processes. In ferroptosis-induced renal I/R injury, iron chelators such as Deferasirox, Deferiprone, and lipophilic antioxidants are currently suppressed lipid peroxidation Liproxstatin-1 (Lip-1), Ferrostatin-1 along with antioxidants like vitamin and quercetin. Ferroptosis has been considered a potential target for pharmaceutical intervention to alleviate renal IRI-associated cell damage. Thus, this review emphasized the role of ferroptosis and its inhibition in renal IRI. Also, Pharmacological modulation of ferroptosis mechanism in renal I/R injury has been conferred. Graphical abstract.
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11
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Chen Y, Su Y, Wang F. The Piezo1 ion channel in glaucoma: a new perspective on mechanical stress. Hum Cell 2022; 35:1307-1322. [PMID: 35767143 DOI: 10.1007/s13577-022-00738-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/09/2022] [Accepted: 06/13/2022] [Indexed: 11/26/2022]
Abstract
Glaucomatous optic nerve damage caused by pathological intraocular pressure elevation is irreversible, and its course is often difficult to control. This group of eye diseases is closely related to biomechanics, and the correlation between glaucoma pathogenesis and mechanical stimulation has been studied in recent decades. The nonselective cation channel Piezo1, the most important known mechanical stress sensor, is a transmembrane protein widely expressed in various cell types. Piezo1 has been detected throughout the eye, and the close relationship between Piezo1 and glaucoma is being confirmed. Pathological changes in glaucoma occur in both the anterior and posterior segments of the eye, and it is of great interest for researchers to determine whether Piezo1 plays a role in these changes and how it functions. The elucidation of the mechanisms of Piezo1 action in nonocular tissues and the reported roles of similar mechanically activated ion channels in glaucoma will provide an appropriate basis for further investigation. From a new perspective, this review provides a detailed description of the current progress in elucidating the role of Piezo1 in glaucoma, including relevant questions and assumptions, the remaining challenging research directions and mechanism-related therapeutic potential.
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Affiliation(s)
- Yidan Chen
- Department of Ophthalmology, Fourth Affiliated Hospital, Harbin Medical University, Yiyuan Road, Harbin, 150001, China
| | - Ying Su
- Eye Hospital, First Affiliated Hospital, Harbin Medical University, Yiman Road, Harbin, 150007, China.
| | - Feng Wang
- Department of Ophthalmology, Fourth Affiliated Hospital, Harbin Medical University, Yiyuan Road, Harbin, 150001, China.
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12
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Li F, Zhou SN, Zeng X, Li Z, Yang R, Wang XX, Meng B, Pei WL, Lu L. Activation of the TREK-1 Potassium Channel Improved Cognitive Deficits in a Mouse Model of Alzheimer's Disease by Modulating Glutamate Metabolism. Mol Neurobiol 2022; 59:5193-5206. [PMID: 35678977 DOI: 10.1007/s12035-022-02776-9] [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: 02/25/2021] [Accepted: 02/10/2022] [Indexed: 10/18/2022]
Abstract
Alzheimer's disease (AD) is a progressive neurodegenerative disease characterized by cognitive dysfunction. The glutamate (Glu) metabolic pathway may be a major contributor to the memory dysfunction associated with AD. The TWIK-related potassium channel-1 (TREK-1) protects against brain ischemia, but any specific role for the channel in AD remains unknown. In this study, we used SAMP8 mice as an AD model and age-matched SAMR1 mice as controls. We explored the trends of changes in TREK-1 channel activity and the levels of AD-related molecules in the brains of SAMP8 mice. We found that the expression level of TREK-1 increased before 3 months of age and then began to decline. The levels of Tau and Glu increased with age whereas the acetylcholine level decreased with age. α-Linolenic acid (ALA), an activator of the TREK-1 channel, significantly increased the TREK-1 level, and improved the learning and memory deficits of SAMP8 mice aged 6 months. The mechanism in play may involve the Glu metabolic pathway. After activation of the TREK-1 channel, damaged neurons and astrocytes were rescued, the levels of Glu and the N-methyl-D-aspartate receptor were downregulated, and the level of glutamate transporter-1 was upregulated. These findings suggest that TREK-1 plays a crucial role in the pathological progression of AD; activation of the TREK-1 channel improved cognitive deficits in SAMP8 mice via a mechanism that involved Glu metabolism. The TREK-1 potassium channel may thus be a valuable therapeutic target in AD patients.
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Affiliation(s)
- Fang Li
- School of Basic Medical Sciences, Lanzhou University, Lanzhou, 73000, Gansu, China
| | - Shu-Ning Zhou
- School of Basic Medical Sciences, Lanzhou University, Lanzhou, 73000, Gansu, China.,The College of Traditional Chinese Medicine, Zhejiang Pharmaceutical College, Ningbo, 315000, Zhejiang, China
| | - Xin Zeng
- School of Basic Medical Sciences, Lanzhou University, Lanzhou, 73000, Gansu, China
| | - Zhen Li
- School of Basic Medical Sciences, Lanzhou University, Lanzhou, 73000, Gansu, China
| | - Rui Yang
- The Endocrinology Department, Lanzhou Hospital of Traditional Chinese Medicine, Lanzhou, 73000, Gansu, China.
| | - Xue-Xi Wang
- School of Basic Medical Sciences, Lanzhou University, Lanzhou, 73000, Gansu, China
| | - Bin Meng
- The Second Clinical Medical College, Lanzhou University, Lanzhou, 73000, Gansu, China
| | - Wei-Lin Pei
- The Second Clinical Medical College, Lanzhou University, Lanzhou, 73000, Gansu, China
| | - Li Lu
- School of Basic Medical Sciences, Lanzhou University, Lanzhou, 73000, Gansu, China.
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13
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Yarishkin O, Phuong TTT, Vazquez-Chona F, Bertrand J, van Battenburg-Sherwood J, Redmon SN, Rudzitis CN, Lakk M, Baumann JM, Freichel M, Hwang EM, Overby D, Križaj D. Emergent Temporal Signaling in Human Trabecular Meshwork Cells: Role of TRPV4-TRPM4 Interactions. Front Immunol 2022; 13:805076. [PMID: 35432302 PMCID: PMC9008486 DOI: 10.3389/fimmu.2022.805076] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 03/02/2022] [Indexed: 11/26/2022] Open
Abstract
Trabecular meshwork (TM) cells are phagocytic cells that employ mechanotransduction to actively regulate intraocular pressure. Similar to macrophages, they express scavenger receptors and participate in antigen presentation within the immunosuppressive milieu of the anterior eye. Changes in pressure deform and compress the TM, altering their control of aqueous humor outflow but it is not known whether transducer activation shapes temporal signaling. The present study combines electrophysiology, histochemistry and functional imaging with gene silencing and heterologous expression to gain insight into Ca2+ signaling downstream from TRPV4 (Transient Receptor Potential Vanilloid 4), a stretch-activated polymodal cation channel. Human TM cells respond to the TRPV4 agonist GSK1016790A with fluctuations in intracellular Ca2+ concentration ([Ca2+]i) and an increase in [Na+]i. [Ca2+]i oscillations coincided with monovalent cation current that was suppressed by BAPTA, Ruthenium Red and the TRPM4 (Transient Receptor Potential Melastatin 4) channel inhibitor 9-phenanthrol. TM cells expressed TRPM4 mRNA, protein at the expected 130-150 kDa and showed punctate TRPM4 immunoreactivity at the membrane surface. Genetic silencing of TRPM4 antagonized TRPV4-evoked oscillatory signaling whereas TRPV4 and TRPM4 co-expression in HEK-293 cells reconstituted the oscillations. Membrane potential recordings suggested that TRPM4-dependent oscillations require release of Ca2+ from internal stores. 9-phenanthrol did not affect the outflow facility in mouse eyes and eyes from animals lacking TRPM4 had normal intraocular pressure. Collectively, our results show that TRPV4 activity initiates dynamic calcium signaling in TM cells by stimulating TRPM4 channels and intracellular Ca2+ release. It is possible that TRPV4-TRPM4 interactions downstream from the tensile and compressive impact of intraocular pressure contribute to homeostatic regulation and pathological remodeling within the conventional outflow pathway.
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Affiliation(s)
- Oleg Yarishkin
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States
| | - Tam T T Phuong
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States
| | - Felix Vazquez-Chona
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States
| | - Jacques Bertrand
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | | | - Sarah N Redmon
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States
| | - Christopher N Rudzitis
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States.,Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, United States
| | - Monika Lakk
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States
| | - Jackson M Baumann
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States.,Department of Bioengineering, University of Utah, Salt Lake City, United States
| | - Marc Freichel
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Eun-Mi Hwang
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, South Korea
| | - Darryl Overby
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - David Križaj
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States.,Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, United States.,Department of Bioengineering, University of Utah, Salt Lake City, United States.,Department of Neurobiology, University of Utah, Salt Lake City, United States
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14
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Kondo R, Deguchi A, Kawata N, Suzuki Y, Yamamura H. Involvement of TREK1 channels in the proliferation of human hepatic stellate LX-2 cells. J Pharmacol Sci 2022; 148:286-294. [DOI: 10.1016/j.jphs.2022.01.003] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2021] [Revised: 12/21/2021] [Accepted: 01/06/2022] [Indexed: 12/12/2022] Open
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15
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Pope L, Minor DL. The Polysite Pharmacology of TREK K 2P Channels. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2022; 1349:51-65. [PMID: 35138610 DOI: 10.1007/978-981-16-4254-8_4] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
K2P (KCNK) potassium channels form "background" or "leak" currents that have critical roles in cell excitability control in the brain, cardiovascular system, and somatosensory neurons. Similar to many ion channel families, studies of K2Ps have been limited by poor pharmacology. Of six K2P subfamilies, the thermo- and mechanosensitive TREK subfamily comprising K2P2.1 (TREK-1), K2P4.1 (TRAAK), and K2P10.1 (TREK-2) are the first to have structures determined for each subfamily member. These structural studies have revealed key architectural features that underlie K2P function and have uncovered sites residing at every level of the channel structure with respect to the membrane where small molecules or lipids can control channel function. This polysite pharmacology within a relatively small (~70 kDa) ion channel comprises four structurally defined modulator binding sites that occur above (Keystone inhibitor site), at the level of (K2P modulator pocket), and below (Fenestration and Modulatory lipid sites) the C-type selectivity filter gate that is at the heart of K2P function. Uncovering this rich structural landscape provides the framework for understanding and developing subtype-selective modulators to probe K2P function that may provide leads for drugs for anesthesia, pain, arrhythmia, ischemia, and migraine.
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Affiliation(s)
- Lianne Pope
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, US
| | - Daniel L Minor
- Cardiovascular Research Institute, University of California San Francisco, San Francisco, CA, US. .,Departments of Biochemistry and Biophysics, and Cellular and Molecular Pharmacology, University of California, San Francisco, CA, USA. .,California Institute for Quantitative Biomedical Research, University of California, San Francisco, CA, USA. .,Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA, USA. .,Molecular Biophysics and Integrated Bio-imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, USA.
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16
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Sundberg CA, Lakk M, Paul S, Figueroa KP, Scoles DR, Pulst SM, Križaj D. The RNA-binding protein and stress granule component ATAXIN-2 is expressed in mouse and human tissues associated with glaucoma pathogenesis. J Comp Neurol 2022; 530:537-552. [PMID: 34350994 PMCID: PMC8716417 DOI: 10.1002/cne.25228] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 07/06/2021] [Indexed: 02/03/2023]
Abstract
Polyglutamine repeat expansions in the Ataxin-2 (ATXN2) gene were first implicated in Spinocerebellar Ataxia Type 2, a disease associated with degeneration of motor neurons and Purkinje cells. Recent studies linked single nucleotide polymorphisms in the gene to elevated intraocular pressure in primary open angle glaucoma (POAG); yet, the localization of ATXN2 across glaucoma-relevant tissues of the vertebrate eye has not been thoroughly examined. This study characterizes ATXN2 expression in the mouse and human retina, and anterior eye, using an antibody validated in ATXN2-/- retinas. ATXN2-ir was localized to cytosolic sub compartments in retinal ganglion cell (RGC) somata and proximal dendrites in addition to GABAergic, glycinergic, and cholinergic amacrine cells in the inner plexiform layer (IPL) and displaced amacrine cells. Human, but not mouse retinas showed modest immunolabeling of bipolar cells. ATXN2 immunofluorescence was prominent in the trabecular meshwork and pigmented and nonpigmented cells of the ciliary body, with analyses of primary human trabecular meshwork cells confirming the finding. The expression of ATXN2 in key POAG-relevant ocular tissues supports the potential role in autophagy and stress granule formation in response to ocular hypertension.
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Affiliation(s)
- Chad A. Sundberg
- Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, Utah, USA
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Monika Lakk
- Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, Utah, USA
| | - Sharan Paul
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Karla P. Figueroa
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Daniel R. Scoles
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - Stefan M. Pulst
- Department of Neurology, University of Utah, Salt Lake City, Utah, USA
| | - David Križaj
- Department of Ophthalmology & Visual Sciences, University of Utah, Salt Lake City, Utah, USA
- Department of Bioengineering, University of Utah, Salt Lake City, Utah, USA
- Department of Neurobiology & Anatomy, University of Utah, Salt Lake City, Utah, USA
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17
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Lapajne L, Rudzitis CN, Cullimore B, Ryskamp D, Lakk M, Redmon S, Yarishkin O, Križaj D. TRPV4: Cell type-specific activation, regulation and function in the vertebrate eye. CURRENT TOPICS IN MEMBRANES 2022; 89:189-219. [PMID: 36210149 PMCID: PMC9879314 DOI: 10.1016/bs.ctm.2022.07.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The architecture of the vertebrate eye is optimized for efficient delivery and transduction of photons and processing of signaling cascades downstream from phototransduction. The cornea, lens, retina, vasculature, ciliary body, ciliary muscle, iris and sclera have specialized functions in ocular protection, transparency, accommodation, fluid regulation, metabolism and inflammatory signaling, which are required to enable function of the retina-light sensitive tissue in the posterior eye that transmits visual signals to relay centers in the midbrain. This process can be profoundly impacted by non-visual stimuli such as mechanical (tension, compression, shear), thermal, nociceptive, immune and chemical stimuli, which target these eye regions to induce pain and precipitate vision loss in glaucoma, diabetic retinopathy, retinal dystrophies, retinal detachment, cataract, corneal dysfunction, ocular trauma and dry eye disease. TRPV4, a polymodal nonselective cation channel, integrate non-visual inputs with homeostatic and signaling functions of the eye. The TRPV4 gene is expressed in most if not all ocular tissues, which vary widely with respect to the mechanisms of TRPV4 channel activation, modulation, oligomerization, and participation in protein- and lipid interactions. Under- and overactivation of TRPV4 may affect intraocular pressure, maintenance of blood-retina barriers, lens accommodation, neuronal function and neuroinflammation. Because TRPV4 dysregulation precipitates many pathologies across the anterior and posterior eye, the channel could be targeted to mitigate vision loss.
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Affiliation(s)
- Luka Lapajne
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132,Department of Ophthalmology, University Medical Centre, University of Ljubljana, Slovenia
| | - Christopher N. Rudzitis
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Brenan Cullimore
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Daniel Ryskamp
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Monika Lakk
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Sarah Redmon
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Oleg Yarishkin
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - David Križaj
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132,Department of Neurobiology, University of Utah, Salt Lake City, UT 84112,Department of Bioengineering, University of Utah, Salt Lake City, UT 84112
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18
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Kim SC, Kim A, Park JY, Hwang EM. Improved AAV vector system for cell-type-specific RNA interference. J Neurosci Methods 2021; 368:109452. [PMID: 34953938 DOI: 10.1016/j.jneumeth.2021.109452] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2021] [Revised: 11/28/2021] [Accepted: 12/17/2021] [Indexed: 01/14/2023]
Abstract
BACKGROUND RNA interference (RNAi) is a powerful technique to effectively silence or knock down gene function in mammalian cells. For better cell-type RNAi experiments in vivo, AAV vector-based RNA interference systems need to be improved. New method: In this study, we developed an AAV vector (CREon shRNA) that expressed CRE-dependent short hairpin RNA (shRNA) and fluorescent proteins simultaneously. RESULTS We verified the Cre-dependent knockdown efficiency of the newly developed CREon shRNA vector in both HEK293T cells overexpressing TREK-1 and PC3 cells with endogenous TREK-1. Next, we packaged this TREK-1 CREon vector with AAV and injected it into the hippocampus of the brain together with a synapsin or GFAP promoter-driven CRE virus, confirming that it works well cell-selectively even in vivo. Finally, this viral vector was applied to an animal model of LPS-induced depression to determine whether behavioral changes occurred. Comparison with existing methods: With the existing pSico or pAAV-Sico-Red vectors, expression of fluorescent protein disappears when shRNA is conditionally activated by CRE recombinase, but our Creon shRNA vector showed simultaneous expression of both shRNA and fluorescent protein. Thus, it offers the advantage of allowing easy visual distinction of knocked-down cells. CONCLUSION The newly improved CREon shRNA vector can be used as a novel research tool for conditional shRNA, and may be useful for various in vivo studies such as cancer and neurobiology.
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Affiliation(s)
- Seung-Chan Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Department of Integrated Biomedical and Life Sciences, College of Health Science, Korea University, Seoul 02841, Republic of Korea
| | - Ajung Kim
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea
| | - Jae-Yong Park
- Department of Integrated Biomedical and Life Sciences, College of Health Science, Korea University, Seoul 02841, Republic of Korea
| | - Eun Mi Hwang
- Brain Science Institute, Korea Institute of Science and Technology (KIST), Seoul 02792, Republic of Korea; Division of Bio-Medical Science & Technology, KIST School, Korea University of Science and Technology (UST), Seoul 02792, Republic of Korea.
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19
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Controlled Decompression Attenuates Compressive Injury following Traumatic Brain Injury via TREK-1-Mediated Inhibition of Necroptosis and Neuroinflammation. OXIDATIVE MEDICINE AND CELLULAR LONGEVITY 2021; 2021:4280951. [PMID: 34790287 PMCID: PMC8592713 DOI: 10.1155/2021/4280951] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/12/2021] [Accepted: 09/24/2021] [Indexed: 11/17/2022]
Abstract
Decompressive craniectomy is an effective strategy to reduce intracranial hypertension after traumatic brain injury (TBI), but it is related to many postoperative complications, such as delayed intracranial hematoma and diffuse brain swelling. Our previous studies have demonstrated that controlled decompression (CDC) surgery attenuates brain injury and reduces the rate of complications after TBI. Here, we investigated the potential molecular mechanisms of CDC in experimental models. The in vitro experiments were performed in a traumatic neuronal injury (TNI) model following compression treatment in primary cultured cortical neurons. We found that compression aggravates TNI-induced neuronal injury, which was significantly attenuated by CDC for 2 h or 3 h. The results of immunocytochemistry showed that CDC reduced neuronal necroptosis and activation of RIP3 induced by TNI and compression, with no effect on RIP1 activity. These protective effects were associated with decreased levels of inflammatory cytokines and preserved intracellular Ca2+ homeostasis. In addition, the expression of the two-pore domain K+ channel TREK-1 and its activity was increased by compression and prolonged by CDC. Treatment with the TREK-1 blockers, spadin or SID1900, could partially prevent the effects of CDC on intracellular Ca2+ metabolism, necroptosis, and neuronal injury following TNI and compression. Using a traumatic intracranial hypertension model in rats, we found that CDC for 20 min or 30 min was effective in alleviating brain edema and locomotor impairment in vivo. CDC significantly inhibited neuronal necroptosis and neuroinflammation and increased TREK-1 activation, and the CDC-induced protection in vivo was attenuated by spadin and SID1900. In summary, CDC is effective in alleviating compressive neuronal injury both in vitro and in vivo, which is associated with the TREK-1-mediated attenuation of intracellular Ca2+ overload, neuronal necroptosis, and neuroinflammation.
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20
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Lakk M, Hoffmann GF, Gorusupudi A, Enyong E, Lin A, Bernstein PS, Toft-Bertelsen T, MacAulay N, Elliott MH, Križaj D. Membrane cholesterol regulates TRPV4 function, cytoskeletal expression, and the cellular response to tension. J Lipid Res 2021; 62:100145. [PMID: 34710431 PMCID: PMC8633027 DOI: 10.1016/j.jlr.2021.100145] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2020] [Revised: 10/08/2021] [Accepted: 10/19/2021] [Indexed: 02/06/2023] Open
Abstract
Despite the association of cholesterol with debilitating pressure-related diseases such as glaucoma, heart disease, and diabetes, its role in mechanotransduction is not well understood. We investigated the relationship between mechanical strain, free membrane cholesterol, actin cytoskeleton, and the stretch-activated transient receptor potential vanilloid isoform 4 (TRPV4) channel in human trabecular meshwork (TM) cells. Physiological levels of cyclic stretch resulted in time-dependent decreases in membrane cholesterol/phosphatidylcholine ratio and upregulation of stress fibers. Depleting free membrane cholesterol with m-β-cyclodextrin (MβCD) augmented TRPV4 activation by the agonist GSK1016790A, swelling and strain, with the effects reversed by cholesterol supplementation. MβCD increased membrane expression of TRPV4, caveolin-1, and flotillin. TRPV4 did not colocalize or interact with caveolae or lipid rafts, apart from a truncated ∼75 kDa variant partially precipitated by a caveolin-1 antibody. MβCD induced currents in TRPV4-expressing Xenopus laevis oocytes. Thus, membrane cholesterol regulates trabecular transduction of mechanical information, with TRPV4 channels mainly located outside the cholesterol-enriched membrane domains. Moreover, the biomechanical milieu itself shapes the lipid content of TM membranes. Diet, cholesterol metabolism, and mechanical stress might modulate the conventional outflow pathway and intraocular pressure in glaucoma and diabetes in part by modulating TM mechanosensing.
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Affiliation(s)
- Monika Lakk
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Grace F Hoffmann
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Aruna Gorusupudi
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Eric Enyong
- Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - Amy Lin
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Paul S Bernstein
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA
| | | | - Nanna MacAulay
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Michael H Elliott
- Dean A. McGee Eye Institute, University of Oklahoma Health Sciences Center, Oklahoma City, OK, USA
| | - David Križaj
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT, USA; Department of Bioengineering, University of Utah, Salt Lake City, UT, USA; Department of Neurobiology, University of Utah, Salt Lake City, UT, USA.
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21
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Lengyel M, Enyedi P, Czirják G. Negative Influence by the Force: Mechanically Induced Hyperpolarization via K 2P Background Potassium Channels. Int J Mol Sci 2021; 22:ijms22169062. [PMID: 34445768 PMCID: PMC8396510 DOI: 10.3390/ijms22169062] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2021] [Revised: 08/19/2021] [Accepted: 08/20/2021] [Indexed: 02/08/2023] Open
Abstract
The two-pore domain K2P subunits form background (leak) potassium channels, which are characterized by constitutive, although not necessarily constant activity, at all membrane potential values. Among the fifteen pore-forming K2P subunits encoded by the KCNK genes, the three members of the TREK subfamily, TREK-1, TREK-2, and TRAAK are mechanosensitive ion channels. Mechanically induced opening of these channels generally results in outward K+ current under physiological conditions, with consequent hyperpolarization and inhibition of membrane potential-dependent cellular functions. In the past decade, great advances have been made in the investigation of the molecular determinants of mechanosensation, and members of the TREK subfamily have emerged among the best-understood examples of mammalian ion channels directly influenced by the tension of the phospholipid bilayer. In parallel, the crucial contribution of mechano-gated TREK channels to the regulation of membrane potential in several cell types has been reported. In this review, we summarize the general principles underlying the mechanical activation of K2P channels, and focus on the physiological roles of mechanically induced hyperpolarization.
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22
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Natale AM, Deal PE, Minor DL. Structural Insights into the Mechanisms and Pharmacology of K 2P Potassium Channels. J Mol Biol 2021; 433:166995. [PMID: 33887333 PMCID: PMC8436263 DOI: 10.1016/j.jmb.2021.166995] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2021] [Revised: 04/08/2021] [Accepted: 04/09/2021] [Indexed: 01/10/2023]
Abstract
Leak currents, defined as voltage and time independent flows of ions across cell membranes, are central to cellular electrical excitability control. The K2P (KCNK) potassium channel class comprises an ion channel family that produces potassium leak currents that oppose excitation and stabilize the resting membrane potential in cells in the brain, cardiovascular system, immune system, and sensory organs. Due to their widespread tissue distribution, K2Ps contribute to many physiological and pathophysiological processes including anesthesia, pain, arrythmias, ischemia, hypertension, migraine, intraocular pressure regulation, and lung injury responses. Structural studies of six homomeric K2Ps have established the basic architecture of this channel family, revealed key moving parts involved in K2P function, uncovered the importance of asymmetric pinching and dilation motions in the K2P selectivity filter (SF) C-type gate, and defined two K2P structural classes based on the absence or presence of an intracellular gate. Further, a series of structures characterizing K2P:modulator interactions have revealed a striking polysite pharmacology housed within a relatively modestly sized (~70 kDa) channel. Binding sites for small molecules or lipids that control channel function are found at every layer of the channel structure, starting from its extracellular side through the portion that interacts with the membrane bilayer inner leaflet. This framework provides the basis for understanding how gating cues sensed by different channel parts control function and how small molecules and lipids modulate K2P activity. Such knowledge should catalyze development of new K2P modulators to probe function and treat a wide range of disorders.
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Affiliation(s)
- Andrew M Natale
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA
| | - Parker E Deal
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA
| | - Daniel L Minor
- Cardiovascular Research Institute, University of California, San Francisco, CA 94158, USA; Departments of Biochemistry and Biophysics, and Cellular and Molecular Pharmacology, University of California, San Francisco, CA 94158, USA; California Institute for Quantitative Biomedical Research, University of California, San Francisco, CA 94158, USA; Kavli Institute for Fundamental Neuroscience University of California, San Francisco, CA 94158, USA; Molecular Biophysics and Integrated Bio-imaging Division Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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23
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Lee H, Lolicato M, Arrigoni C, Minor DL. Production of K 2P2.1 (TREK-1) for structural studies. Methods Enzymol 2021; 653:151-188. [PMID: 34099170 DOI: 10.1016/bs.mie.2021.02.013] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
K2P (KCNK) potassium channels form 'background' or 'leak' currents that are important for controlling cell excitability in the brain, cardiovascular system, and somatosensory neurons. K2P2.1 (TREK-1) is one of the founding members of this family and one of the first well-characterized polymodal ion channels capable of responding to a variety of physical and chemical gating cues. Of the six K2P subfamilies, the thermo-and mechano-sensitive TREK subfamily comprising K2P2.1 (TREK-1), K2P4.1 (TRAAK), and K2P10.1 (TREK-2) is the first to have structures determined for each subfamily member. These structural studies have revealed key architectural features that provide a framework for understanding how gating cues sensed by different channel elements converge on the K2P selectivity filter C-type gate. TREK family structural studies have also revealed numerous sites where small molecules or lipids bind and affect channel function. This rich structural landscape provides the framework for probing K2P function and for the development of new K2P-directed agents. Such molecules may be useful for affecting processes where TREK channels are important such as anesthesia, pain, arrythmia, ischemia, migraine, intraocular pressure, and lung injury. Production of high quality protein samples is key to addressing new questions about K2P function and pharmacology. Here, we present methods for producing pure K2P2.1 (TREK-1) suitable for advancing towards these goals through structural and biochemical studies.
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Affiliation(s)
- Haerim Lee
- Cardiovascular Research Institute, University of California, San Francisco, CA, United States
| | - Marco Lolicato
- Cardiovascular Research Institute, University of California, San Francisco, CA, United States
| | - Cristina Arrigoni
- Cardiovascular Research Institute, University of California, San Francisco, CA, United States
| | - Daniel L Minor
- Cardiovascular Research Institute, University of California, San Francisco, CA, United States; Departments of Biochemistry and Biophysics, and Cellular and Molecular Pharmacology, University of California, San Francisco, CA, United States; California Institute for Quantitative Biomedical Research, University of California, San Francisco, CA, United States; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA, United States; Molecular Biophysics and Integrated Bio-imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA, United States.
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Mechanical stretch induces Ca 2+ influx and extracellular release of PGE 2 through Piezo1 activation in trabecular meshwork cells. Sci Rep 2021; 11:4044. [PMID: 33597646 PMCID: PMC7890064 DOI: 10.1038/s41598-021-83713-z] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2020] [Accepted: 02/01/2021] [Indexed: 11/22/2022] Open
Abstract
The trabecular meshwork (TM) constitutes the main pathway for aqueous humor drainage and is exposed to complex intraocular pressure fluctuations. The mechanism of homeostasis in which TM senses changes in intraocular pressure and leads to normal levels of outflow resistance is not yet well understood. Previous reports have shown that Piezo1, a mechanically-activated cation channel, is expressed in TM and isolated TM cells. Therefore, we tested hypothesis that Piezo1 may function in response to membrane tension and stretch in TM. In human trabecular meshwork (hTM) cells, PIEZO1 was showed to be abundantly expressed, and Piezo1 agonist Yoda1 and mechanical stretch caused a Piezo1-dependent Ca2+ influx and release of arachidonic acid and PGE2. Treatment with Yoda1 or PGE2 significantly inhibited hTM cell contraction. These results suggest that mechanical stretch stimuli in TM activates Piezo1 and subsequently regulates TM cell contraction by triggering Ca2+ influx and release of arachidonic acid and PGE2. Thus, Piezo1 could acts as a regulator of intraocular pressure (IOP) within the conventional outflow pathway and could be a novel therapeutic strategy to modulate IOP in glaucoma patients.
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25
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Zhu W, Hou F, Fang J, Bahrani Fard MR, Liu Y, Ren S, Wu S, Qi Y, Sui S, Read AT, Sherwood JM, Zou W, Yu H, Zhang J, Overby DR, Wang N, Ethier CR, Wang K. The role of Piezo1 in conventional aqueous humor outflow dynamics. iScience 2021; 24:102042. [PMID: 33532718 PMCID: PMC7829208 DOI: 10.1016/j.isci.2021.102042] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2020] [Revised: 12/16/2020] [Accepted: 01/05/2021] [Indexed: 12/16/2022] Open
Abstract
Controlling intraocular pressure (IOP) remains the mainstay of glaucoma therapy. The trabecular meshwork (TM), the key tissue responsible for aqueous humor (AH) outflow and IOP maintenance, is very sensitive to mechanical forces. However, it is not understood whether Piezo channels, very sensitive mechanosensors, functionally influence AH outflow. Here, we characterize the role of Piezo1 in conventional AH outflow. Immunostaining and western blot analysis showed that Piezo1 is widely expressed by TM. Patch-clamp recordings in TM cells confirmed the activation of Piezo1-derived mechanosensitive currents. Importantly, the antagonist GsMTx4 for mechanosensitive channels significantly decreased steady-state facility, yet activation of Piezo1 by the specific agonist Yoda1 did not lead to a facility change. Furthermore, GsMTx4, but not Yoda1, caused a significant increase in ocular compliance, a measure of the eye's transient response to IOP perturbation. Our findings demonstrate a potential role for Piezo1 in conventional outflow, likely under pathological and rapid transient conditions. Piezo1 is functionally expressed in the TM, the most important tissue controlling IOP Suppression of mechanosensitive channel leads to a significant decrease in facility Our data suggest a role for Piezo in pathological situations and rapid IOP transients
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Affiliation(s)
- Wei Zhu
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao University Medical College, 38 Dengzhou Road, Qingdao 266021, Shandong, China.,Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University & Capital Medical University, Beijing 100730, China
| | - Fei Hou
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao University Medical College, 38 Dengzhou Road, Qingdao 266021, Shandong, China.,Department of Pharmacy, Affiliated Hospital of Qingdao University, Qingdao 266003, China
| | - Jingwang Fang
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao University Medical College, 38 Dengzhou Road, Qingdao 266021, Shandong, China
| | - Mohammad Reza Bahrani Fard
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta 30332, GA, USA
| | - Yani Liu
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao University Medical College, 38 Dengzhou Road, Qingdao 266021, Shandong, China
| | - Shouyan Ren
- Department of Pharmacy, Affiliated Hospital of Qingdao University, Qingdao 266003, China
| | - Shen Wu
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital Eye Center, Beijing 100730 China
| | - Yunkun Qi
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao University Medical College, 38 Dengzhou Road, Qingdao 266021, Shandong, China
| | - Shangru Sui
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao University Medical College, 38 Dengzhou Road, Qingdao 266021, Shandong, China
| | - A Thomas Read
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta 30332, GA, USA
| | | | - Wei Zou
- School of Mechatronic Engineering, Jiangsu Normal University, Xuzhou 221116, China
| | - Hongxia Yu
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao University Medical College, 38 Dengzhou Road, Qingdao 266021, Shandong, China
| | - Jingxue Zhang
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital Eye Center, Beijing 100730 China
| | - Darryl R Overby
- Department of Bioengineering, Imperial College London, London, UK
| | - Ningli Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital Eye Center, Beijing 100730 China
| | - C Ross Ethier
- George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta 30332, GA, USA.,Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, 30332, GA, United States
| | - KeWei Wang
- Department of Pharmacology, School of Pharmacy, Qingdao University, Qingdao University Medical College, 38 Dengzhou Road, Qingdao 266021, Shandong, China.,Institute of Innovative Drugs, Qingdao University, 38 Dengzhou Road, Qingdao 266021, Shandong, China
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26
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Reina-Torres E, Boussommier-Calleja A, Sherwood JM, Overby DR. Aqueous Humor Outflow Requires Active Cellular Metabolism in Mice. Invest Ophthalmol Vis Sci 2021; 61:45. [PMID: 32845955 PMCID: PMC7452856 DOI: 10.1167/iovs.61.10.45] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022] Open
Abstract
Purpose Conventional wisdom posits that aqueous humor leaves the eye by passive bulk flow without involving energy-dependent processes. However, recent studies have shown that active processes, such as cell contractility, contribute to outflow regulation. Here, we examine whether inhibiting cellular metabolism affects outflow facility in mice. Methods We measured outflow facility in paired enucleated eyes from C57BL/6J mice using iPerfusion. We had three Experimental Sets: ES1, perfused at 35°C versus 22°C; ES2, perfused with metabolic inhibitors versus vehicle at 35°C; and ES3, perfused at 35°C versus 22°C in the presence of metabolic inhibitors. Inhibitors targeted glycolysis and oxidative phosphorylation (2-deoxy-D-glucose, 3PO and sodium azide). We also measured adenosine triphosphate (ATP) levels in separate murine anterior segments treated like ES1 and ES2. Results Reducing temperature decreased facility by 63% [38%, 78%] (mean [95% confidence interval (CI)], n = 10 pairs; P = 0.002) in ES1 after correcting for changes in viscosity. Metabolic inhibitors reduced facility by 21% [9%, 31%] (n = 9, P = 0.006) in ES2. In the presence of inhibitors, temperature reduction decreased facility by 44% [29%, 56%] (n = 8, P < 0.001) in ES3. Metabolic inhibitors reduced anterior segment adenosine triphosphate (ATP) levels by 90% [83%, 97%] (n = 5, P<<0.001), but reducing temperature did not affect ATP. Conclusions Inhibiting cellular metabolism decreases outflow facility within minutes. This implies that outflow is not entirely passive, but depends partly on energy-dependent cellular processes, at least in mice. This study also suggests that there is a yet unidentified mechanism, which is strongly temperature-dependent but metabolism-independent, that is necessary for nearly half of normal outflow function in mice.
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Affiliation(s)
- Ester Reina-Torres
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | | | - Joseph M Sherwood
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - Darryl R Overby
- Department of Bioengineering, Imperial College London, London, United Kingdom
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27
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Pang JJ. Roles of the ocular pressure, pressure-sensitive ion channel, and elasticity in pressure-induced retinal diseases. Neural Regen Res 2021; 16:68-72. [PMID: 32788449 PMCID: PMC7818868 DOI: 10.4103/1673-5374.286953] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The intraocular pressure inside the human eye maintains 10–21 mmHg above the atmospheric pressure. Elevation of intraocular pressure is highly correlated with the retinopathy in glaucoma, and changes in the exterior pressure during mountain hiking, air traveling, and diving may also induce vision decline and retinopathy. The pathophysiological mechanism of these pressure-induced retinal disorders has not been completely clear. Retinal neurons express pressure-sensitive channels intrinsically sensitive to pressure and membrane stretch, such as the transient receptor potential channel (TRP) family permeable to Ca2+ and Na+ and the two-pore domain K channel family. Recent data have shown that pressure excites the primate retinal bipolar cell by opening TRP vanilloid 4 to mediate transient depolarizing currents, and TRP vanilloid 4 agonists enhance the membrane excitability of primate retinal ganglion cells. The eyeball wall is constructed primarily by the sclera and cornea of low elasticity, and the flow rate of the aqueous humor and intraocular pressure both fluctuate, but the mathematical relationship between the ocular elasticity, aqueous humor volume, and intraocular pressure has not been established. This review will briefly review recent literature on the pressure-related retinal pathophysiology in glaucoma and other pressure-induced retinal disorders, the elasticity of ocular tissues, and pressure-sensitive cation channels in retinal neurons. Emerging data support the global volume and the elasticity and thickness of the sclera and cornea as variables to affect the intraocular pressure level like the volume of the aqueous humor. Recent results also suggest some potential routes for TRPs to mediate retinal ganglion cell dysfunction: TRP opening upon intraocular pressure elevation and membrane stretch, enhancing glutamate release from bipolar cells, increasing intracellular Na+, Ca2+ concentration in retinal ganglion cells and extracellular glutamate concentration, inactivating voltage-gated Na+ channels, and causing excitotoxicity and dysfunction of retinal ganglion cells. Further studies on these routes likely identify novel targets and therapeutic strategies for the treatment of pressure-induced retinal disorders.
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Affiliation(s)
- Ji-Jie Pang
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, USA
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28
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Yarishkin O, Phuong TTT, Baumann JM, De Ieso ML, Vazquez-Chona F, Rudzitis CN, Sundberg C, Lakk M, Stamer WD, Križaj D. Piezo1 channels mediate trabecular meshwork mechanotransduction and promote aqueous fluid outflow. J Physiol 2021; 599:571-592. [PMID: 33226641 PMCID: PMC7849624 DOI: 10.1113/jp281011] [Citation(s) in RCA: 34] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Accepted: 11/17/2020] [Indexed: 01/13/2023] Open
Abstract
KEY POINTS Trabecular meshwork (TM) is a highly mechanosensitive tissue in the eye that regulates intraocular pressure through the control of aqueous humour drainage. Its dysfunction underlies the progression of glaucoma but neither the mechanisms through which TM cells sense pressure nor their role in aqueous humour outflow are understood at the molecular level. We identified the Piezo1 channel as a key TM transducer of tensile stretch, shear flow and pressure. Its activation resulted in intracellular signals that altered organization of the cytoskeleton and cell-extracellular matrix contacts and modulated the trabecular component of aqueous outflow whereas another channel, TRPV4, mediated a delayed mechanoresponse. This study helps elucidate basic mechanotransduction properties that may contribute to intraocular pressure regulation in the vertebrate eye. ABSTRACT Chronic elevations in intraocular pressure (IOP) can cause blindness by compromising the function of trabecular meshwork (TM) cells in the anterior eye, but how these cells sense and transduce pressure stimuli is poorly understood. Here, we demonstrate functional expression of two mechanically activated channels in human TM cells. Pressure-induced cell stretch evoked a rapid increase in transmembrane current that was inhibited by antagonists of the mechanogated channel Piezo1, Ruthenium Red and GsMTx4, and attenuated in Piezo1-deficient cells. The majority of TM cells exhibited a delayed stretch-activated current that was mediated independently of Piezo1 by TRPV4 (transient receptor potential cation channel, subfamily V, member 4) channels. Piezo1 functions as the principal TM transducer of physiological levels of shear stress, with both shear and the Piezo1 agonist Yoda1 increasing the number of focal cell-matrix contacts. Analysis of TM-dependent fluid drainage from the anterior eye showed significant inhibition by GsMTx4. Collectively, these results suggest that TM mechanosensitivity utilizes kinetically, regulatory and functionally distinct pressure transducers to inform the cells about force-sensing contexts. Piezo1-dependent control of shear flow sensing, calcium homeostasis, cytoskeletal dynamics and pressure-dependent outflow suggests potential for a novel therapeutic target in treating glaucoma.
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Affiliation(s)
- Oleg Yarishkin
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Tam T T Phuong
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Jackson M Baumann
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
| | - Michael L De Ieso
- Duke Eye Center, Duke University School of Medicine, Durham, NC, USA
| | - Felix Vazquez-Chona
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Christopher N Rudzitis
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Chad Sundberg
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - Monika Lakk
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
| | - W Daniel Stamer
- Duke Eye Center, Duke University School of Medicine, Durham, NC, USA
| | - David Križaj
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, UT, USA
- Department of Bioengineering, University of Utah, Salt Lake City, UT, USA
- Department of Neurobiology and Anatomy, University of Utah School of Medicine, Salt Lake City, UT, USA
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29
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Swain SM, Liddle RA. Pressure-sensing Piezo1: the eyes have it. J Physiol 2021; 599:365-366. [PMID: 33372279 PMCID: PMC8294074 DOI: 10.1113/jp281122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022] Open
Affiliation(s)
- Sandip M Swain
- Department of Medicine, Duke University and Department of Veterans Affairs Medical Centers, Durham, NC, USA
| | - Rodger A Liddle
- Department of Medicine, Duke University and Department of Veterans Affairs Medical Centers, Durham, NC, USA
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30
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Guarino BD, Paruchuri S, Thodeti CK. The role of TRPV4 channels in ocular function and pathologies. Exp Eye Res 2020; 201:108257. [PMID: 32979394 DOI: 10.1016/j.exer.2020.108257] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2020] [Revised: 09/17/2020] [Accepted: 09/18/2020] [Indexed: 12/15/2022]
Abstract
Transient potential receptor vanilloid 4 (TRPV4) is an ion channel responsible for sensing osmotic and mechanical signals, which in turn regulates calcium signaling across cell membranes. TRPV4 is widely expressed throughout the body, and plays an important role in normal physiological function, as well as different pathologies, however, its role in the eye is not well known. In the eye, TRPV4 is expressed in various tissues, such as the retina, corneal epithelium, ciliary body, and the lens. In this review, we provide an overview on TRPV4 structure, activation, mutations, and summarize the current knowledge of TRPV4 function and signaling mechanisms in various locations throughout the eye, as well as its role in ocular diseases, such as glaucoma and diabetic retinopathy. Based on the available data, we highlight the therapeutic potential of TRPV4 as well as the shortcomings of current research. Finally, we provide future perspectives on the implications of targeting TRPV4 to treat various ocular pathologies.
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Affiliation(s)
- Brianna D Guarino
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, 44272, USA
| | | | - Charles K Thodeti
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH, 44272, USA.
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31
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Pope L, Lolicato M, Minor DL. Polynuclear Ruthenium Amines Inhibit K 2P Channels via a "Finger in the Dam" Mechanism. Cell Chem Biol 2020; 27:511-524.e4. [PMID: 32059793 PMCID: PMC7245552 DOI: 10.1016/j.chembiol.2020.01.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/02/2019] [Revised: 01/16/2020] [Accepted: 01/27/2020] [Indexed: 12/11/2022]
Abstract
The trinuclear ruthenium amine ruthenium red (RuR) inhibits diverse ion channels, including K2P potassium channels, TRPs, the calcium uniporter, CALHMs, ryanodine receptors, and Piezos. Despite this extraordinary array, there is limited information for how RuR engages targets. Here, using X-ray crystallographic and electrophysiological studies of an RuR-sensitive K2P, K2P2.1 (TREK-1) I110D, we show that RuR acts by binding an acidic residue pair comprising the "Keystone inhibitor site" under the K2P CAP domain archway above the channel pore. We further establish that Ru360, a dinuclear ruthenium amine not known to affect K2Ps, inhibits RuR-sensitive K2Ps using the same mechanism. Structural knowledge enabled a generalizable design strategy for creating K2P RuR "super-responders" having nanomolar sensitivity. Together, the data define a "finger in the dam" inhibition mechanism acting at a novel K2P inhibitor binding site. These findings highlight the polysite nature of K2P pharmacology and provide a new framework for K2P inhibitor development.
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Affiliation(s)
- Lianne Pope
- Cardiovascular Research Institute, University of California, San Francisco, CA 93858-2330, USA
| | - Marco Lolicato
- Cardiovascular Research Institute, University of California, San Francisco, CA 93858-2330, USA
| | - Daniel L Minor
- Cardiovascular Research Institute, University of California, San Francisco, CA 93858-2330, USA; Departments of Biochemistry and Biophysics, and Cellular and Molecular Pharmacology, University of California, San Francisco, CA 93858-2330, USA; California Institute for Quantitative Biomedical Research, University of California, San Francisco, CA 93858-2330, USA; Kavli Institute for Fundamental Neuroscience, University of California, San Francisco, CA 93858-2330, USA; Molecular Biophysics and Integrated Bio-imaging Division, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA.
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32
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Ulkumen B, Artunc Ulkumen B, Batir MB, Cam S, Vatansever S. The Role of TREK-1 and AQP5 in Gonadocorticoid-Related Voice Disorders. J Voice 2020; 36:150-155. [PMID: 32439217 DOI: 10.1016/j.jvoice.2020.04.024] [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: 02/02/2020] [Revised: 04/22/2020] [Accepted: 04/23/2020] [Indexed: 10/24/2022]
Abstract
OBJECTIVES TWIK-related potassium channel-1 (TREK-1) and Aquaporin 5 (AQP5) are involved in epithelial integrity and fluid transport, respectively. In this study, we aimed to compare physiological and gestational patterns of TREK-1 and AQP5 location and expression in rat larynx. Our secondary objective was to reveal the effect of estradiol (E2) and progesterone (PG) on these two biomolecules. METHODS This study was conducted on 20 Wister albino female rats which were assigned as control (group A) and pregnant group (group B). The rats were sacrificed at 20th day of pregnancy. Blood was obtained directly from the ventricle for detection of serum E2 and PG levels. Larynx was resected for immunohistochemical analyses and real-time polymerase chain reaction testing for detection of TREK-1 and AQP5 staining and expression, respectively. RESULTS Relative TREK-1 (P = 0.035) and AQP5 (P = 0.019) expression was found to be significantly high in group B when compared with group A. We found positive correlation between serum E2 levels and both biomolecules (TREK-1; P = 0.018, AQP5; P = 0.016). We also found positive correlation between serum PG levels and both biomolecules (TREK-1; P = 0.001, AQP5; P = 0.019). TREK-1 immunostaining was found to be higher in surface epithelium and lamina propria of vocal cord mucosa. AQP5 was particularly found to be located in basement membrane and adjacent superficial lamina propria. We revealed the physiological and gestational pattern of laryngeal TREK-1 and AQP5 expression for the first time. Gestational expression of both TREK-1 and AQP5 was found to be increased. Stimulatory effect of E2 and PG on laryngeal TREK-1 and AQP5 expression was also revealed. CONCLUSIONS We revealed upregulatory effect of E2 and PG on laryngeal TREK-1 and AQP5 expression. Based on this finding, it can be suggested that TREK-1 and AQP5 play role in biomolecular processes leading gonadocorticoid-related voice changes.
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Affiliation(s)
- Burak Ulkumen
- Department of Otorhinolaryngology-Head Neck Surgery, Faculty of Medicine, Manisa Celal Bayar University, Manisa, Turkey.
| | - Burcu Artunc Ulkumen
- Department of Obstetrics and Gynecology, Faculty of Medicine, Manisa Celal Bayar University, Manisa, Turkey
| | - Muhammet Burak Batir
- Department of Biology, Faculty of Science and Letters, Manisa Celal Bayar University, Manisa, Turkey
| | - Sirri Cam
- Department of Medical Genetics, Faculty of Medicine, Manisa Celal Bayar University, Manisa, Turkey
| | - Seda Vatansever
- Department of Histology-Embryology, Faculty of Medicine, Manisa Celal Bayar University, Manisa, Turkey; Experimental Research Center of Health (DESAM), Near East University, Mersin, Turkey
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33
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Yarishkin O, Baumann JM, Križaj D. Mechano-electrical transduction in trabecular meshwork involves parallel activation of TRPV4 and TREK-1 channels. Channels (Austin) 2019; 13:168-171. [PMID: 31161865 PMCID: PMC6557601 DOI: 10.1080/19336950.2019.1618149] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023] Open
Affiliation(s)
- Oleg Yarishkin
- a Department of Ophthalmology and Visual Sciences , University of Utah , Salt lake City , UT , USA
| | - Jackson M Baumann
- a Department of Ophthalmology and Visual Sciences , University of Utah , Salt lake City , UT , USA.,b Department of Bioengineering , University of Utah , Salt Lake City , UT , USA
| | - David Križaj
- a Department of Ophthalmology and Visual Sciences , University of Utah , Salt lake City , UT , USA.,b Department of Bioengineering , University of Utah , Salt Lake City , UT , USA.,c Department of Neurobiology and Anatomy , University of Utah , Salt lake City , UT , USA
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34
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Yarishkin O, Phuong TTT, Križaj D. Trabecular Meshwork TREK-1 Channels Function as Polymodal Integrators of Pressure and pH. Invest Ophthalmol Vis Sci 2019; 60:2294-2303. [PMID: 31117121 PMCID: PMC6532698 DOI: 10.1167/iovs.19-26851] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
Purpose The concentration of protons in the aqueous humor (AH) of the vertebrate eye is maintained close to blood pH; however, pathologic conditions and surgery may shift it by orders of magnitude. We investigated whether and how changes in extra- and intracellular pH affect the physiology and function of trabecular meshwork (TM) cells that regulate AH outflow. Methods Electrophysiology, in conjunction with pharmacology, gene knockdown, and optical recording, was used to track the pH dependence of transmembrane currents and mechanotransduction in primary and immortalized human TM cells. Results Extracellular acidification depolarized the resting membrane potential by inhibiting an outward K+-mediated current, whereas alkalinization hyperpolarized the cells and augmented the outward conductance. Intracellular acidification with sodium bicarbonate hyperpolarized TM cells, whereas removal of intracellular protons with ammonium chloride depolarized the membrane potential. The effects of extra- and intracellular acid and alkaline loading were abolished by quinine, a pan-selective inhibitor of two-pore domain potassium (K2P) channels, and suppressed by shRNA-mediated downregulation of the mechanosensitive K2P channel TREK-1. Extracellular acidosis suppressed, whereas alkalosis facilitated, the amplitude of the pressure-evoked TREK-1–mediated outward current. Conclusions These results demonstrate that TM mechanotransduction mediated by TREK-1 channels is profoundly sensitive to extra- and intracellular pH shifts. Intracellular acidification might modulate aqueous outflow and IOP by stimulating TREK-1 channels.
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Affiliation(s)
- Oleg Yarishkin
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States
| | - Tam T T Phuong
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States
| | - David Križaj
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah, United States.,Department of Neurobiology and Anatomy, University of Utah, Salt Lake City, Utah, United States.,Department of Bioengineering, University of Utah, Salt Lake City, Utah, United States
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