1
|
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.
Collapse
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.
| |
Collapse
|
2
|
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.
Collapse
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.
| |
Collapse
|
3
|
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.
Collapse
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
| |
Collapse
|
4
|
Wang Y, Zhang W, Xu G, Shi C, Wang X, Qu J, Wang H, Liu C. The role of TRPV4 in the regulation of retinal ganglion cells apoptosis in rat and mouse. Heliyon 2023; 9:e17583. [PMID: 37456002 PMCID: PMC10338314 DOI: 10.1016/j.heliyon.2023.e17583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Revised: 06/18/2023] [Accepted: 06/21/2023] [Indexed: 07/18/2023] Open
Abstract
Retinal ganglion cell (RGC) damages are common in glaucoma, causing atrophy of the optic papilla, visual field damage, and visual loss. Transient receptor potential vanilloid 4 (TRPV4) is significantly expressed in the eyeball and is sensitive to mechanical and osmotic pressure. However, the specific role and mechanism of TRPV4 in glaucoma and RGC progression remain unclear. TRPV4 expression was detected in RGCs under different pressure culture conditions. We also explored the pressure effect on TRPV4 expression and the role and mechanism behind the functional regulation of RGCs. Immunofluorescence staining, western blotting, and TUNEL were utilized in this study. Our results established that TRPV4 was expressed in RGCs. TRPV4 expression was decreased at 40 mmHg and 60 mmHg, and the expression of BAX at 40 mmHg, 60 mmHg. Additionally, the expression of caspase 9 protein increased at 40 mmHg with the pressure increase compared with the conventional culture group. TUNEL staining revealed that the apoptosis rate of RGCs was elevated at 40 mmHg and 60 mmHg, compared with the traditional culture group. Therefore, the expression of BAX and caspase 9 increased, along with the apoptosis rate of RGCs compared with the control group. However, after TRPV4 antagonist treatment, the expression of BAX and caspase 9 decreased, and the apoptosis rate of RGCs decreased. Thus, TRPV4 may affect the mitochondrial apoptosis pathway, such as BAX and caspase 9, leading to the apoptosis of RGCs. The antagonists of TRPV4 could provide a new idea for clinically treating acute glaucoma.
Collapse
Affiliation(s)
- Yi Wang
- Department of Ophthalmology, The Second Affiliated Hospital of Shandong First Medical University, Taian, Shandong, 271000, China
| | - Wei Zhang
- School of Medicine, Southeast University, Nanjing, 210009, China
| | - Guozheng Xu
- Department of Physiology and Neurobiology, Functional Laboratory, Shandong First Medical University, Jinan, Shandong, 250117, China
| | - Changwei Shi
- Department of Physiology and Neurobiology, Functional Laboratory, Shandong First Medical University, Jinan, Shandong, 250117, China
| | - Xiang Wang
- School of Clinical Medicine, Shandong First Medical University & Shandong Academy of Medical Sciences, Taian, Shandong, 271016, China
| | - Jianfeng Qu
- Medical Engineering and Technology Research Center, Shandong First Medical University, Taian, Shandong, 271000, China
| | - Hongmei Wang
- School of Medicine, Southeast University, Nanjing, 210009, China
| | - Chunhua Liu
- Department of Physiology and Neurobiology, Functional Laboratory, Shandong First Medical University, Jinan, Shandong, 250117, China
| |
Collapse
|
5
|
Wang HN, Qian WJ, Zhao GL, Li F, Miao YY, Lei B, Sun XH, Wang ZF. L- and T-type Ca 2+ channels dichotomously contribute to retinal ganglion cell injury in experimental glaucoma. Neural Regen Res 2023; 18:1570-1577. [PMID: 36571364 PMCID: PMC10075096 DOI: 10.4103/1673-5374.360277] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
Abstract
Retinal ganglion cell apoptotic death is the main pathological characteristic of glaucoma, which is the leading cause of irreversible blindness. Disruption of Ca2+ homeostasis plays an important role in glaucoma. Voltage-gated Ca2+ channel blockers have been shown to improve vision in patients with glaucoma. However, whether and how voltage-gated Ca2+ channels are involved in retinal ganglion cell apoptotic death are largely unknown. In this study, we found that total Ca2+ current densities in retinal ganglion cells were reduced in a rat model of chronic ocular hypertension experimental glaucoma, as determined by whole-cell patch-clamp electrophysiological recordings. Further analysis showed that L-type Ca2+ currents were downregulated while T-type Ca2+ currents were upregulated at the later stage of glaucoma. Western blot assay and immunofluorescence experiments confirmed that expression of the CaV1.2 subunit of L-type Ca2+ channels was reduced and expression of the CaV3.3 subunit of T-type Ca2+ channels was increased in retinas of the chronic ocular hypertension model. Soluble tumor necrosis factor-α, an important inflammatory factor, inhibited the L-type Ca2+ current of isolated retinal ganglion cells from control rats and enhanced the T-type Ca2+ current. These changes were blocked by the tumor necrosis factor-α inhibitor XPro1595, indicating that both types of Ca2+ currents may be mediated by soluble tumor necrosis factor-α. The intracellular mitogen-activated protein kinase/extracellular signal-regulated kinase pathway and nuclear factor kappa-B signaling pathway mediate the effects of tumor necrosis factor-α. TUNEL assays revealed that mibefradil, a T-type calcium channel blocker, reduced the number of apoptotic retinal ganglion cells in the rat model of chronic ocular hypertension. These results suggest that T-type Ca2+ channels are involved in disrupted Ca2+ homeostasis and apoptosis of retinal ganglion cells in glaucoma, and application of T-type Ca2+ channel blockers, especially a specific CaV3.3 blocker, may be a potential strategy for the treatment of glaucoma.
Collapse
Affiliation(s)
- Hong-Ning Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Wen-Jing Qian
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Guo-Li Zhao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Fang Li
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Yan-Ying Miao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Bo Lei
- Institutes of Neuroscience and Third Affiliated Hospital, Henan Provincial People's Hospital, Henan Eye Institute, Henan Eye Hospital, People's Hospital of Zhengzhou University, Zhengzhou University, Zhengzhou, Henan Province, China
| | - Xing-Huai Sun
- Eye Institute and Department of Ophthalmology, Eye & ENT Hospital, NHC Key Laboratory of Myopia, Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, China
| | - Zhong-Feng Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, China
| |
Collapse
|
6
|
Beardslee LA, Halman JR, Unser AM, Xie Y, Danias J, Bergkvist M, Sharfstein ST, Torrejon KY. Recreating the Trabecular Outflow Tissue on Implantable, Micropatterned, Ultrathin, Porous Polycaprolactone Scaffolds. Bioengineering (Basel) 2023; 10:679. [PMID: 37370610 DOI: 10.3390/bioengineering10060679] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/09/2022] [Revised: 05/17/2023] [Accepted: 05/28/2023] [Indexed: 06/29/2023] Open
Abstract
Glaucoma, where increased intraocular pressure (IOP) leads to damage to the optic nerve and loss of sight, is amongst the foremost causes of irreversible blindness worldwide. In primary open angle glaucoma, the increased IOP is a result of the malfunctioning human trabecular meshwork (HTM) cells' inability to properly regulate the outflow of aqueous humor from the eye. A potential future treatment for glaucoma is to replace damaged HTM cells with a tissue-engineered substitute, thus restoring proper fluid outflow. Polycaprolactone (PCL) is a versatile, biodegradable, and implantable material that is widely used for cell culture and tissue engineering. In this work, PCL scaffolds were lithographically fabricated using a sacrificial process to produce submicron-thick scaffolds with openings of specific sizes and shapes (e.g., grid, hexagonal pattern). The HTM cell growth on gelatin-coated PCL scaffolds was assessed by scanning electron microscopy, tetrazolium metabolic activity assay, and cytoskeletal organization of F-actin. Expression of HTM-specific markers and ECM deposition were assessed by immunocytochemistry and qPCR analysis. Gelatin-coated, micropatterned, ultrathin, porous PCL scaffolds with a grid pattern supported proper HTM cell growth, cytoskeleton organization, HTM-marker expression, and ECM deposition, demonstrating the feasibility of using these PCL scaffolds to tissue-engineer implantable, healthy ocular outflow tissue.
Collapse
Affiliation(s)
- Luke A Beardslee
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, NY 12203, USA
| | - Justin R Halman
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, NY 12203, USA
| | - Andrea M Unser
- Department of Ophthalmology, SUNY Downstate Health Sciences University, 450 Clackson Avenue, Brooklyn, NY 11203, USA
| | - Yubing Xie
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, NY 12203, USA
| | - John Danias
- Department of Ophthalmology, SUNY Downstate Health Sciences University, 450 Clackson Avenue, Brooklyn, NY 11203, USA
| | - Magnus Bergkvist
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, NY 12203, USA
| | - Susan T Sharfstein
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, NY 12203, USA
| | - Karen Y Torrejon
- Colleges of Nanoscale Science and Engineering, SUNY Polytechnic Institute, 257 Fuller Road, Albany, NY 12203, USA
- Glauconix Biosciences Inc., 251 Fuller Road, Albany, NY 12203, USA
| |
Collapse
|
7
|
Sharif NA. Recently Approved Drugs for Lowering and Controlling Intraocular Pressure to Reduce Vision Loss in Ocular Hypertensive and Glaucoma Patients. Pharmaceuticals (Basel) 2023; 16:791. [PMID: 37375739 DOI: 10.3390/ph16060791] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2023] [Revised: 05/17/2023] [Accepted: 05/19/2023] [Indexed: 06/29/2023] Open
Abstract
Serious vision loss occurs in patients affected by chronically raised intraocular pressure (IOP), a characteristic of many forms of glaucoma where damage to the optic nerve components causes progressive degeneration of retinal and brain neurons involved in visual perception. While many risk factors abound and have been validated for this glaucomatous optic neuropathy (GON), the major one is ocular hypertension (OHT), which results from the accumulation of excess aqueous humor (AQH) fluid in the anterior chamber of the eye. Millions around the world suffer from this asymptomatic and progressive degenerative eye disease. Since clinical evidence has revealed a strong correlation between the reduction in elevated IOP/OHT and GON progression, many drugs, devices, and surgical techniques have been developed to lower and control IOP. The constant quest for new pharmaceuticals and other modalities with superior therapeutic indices has recently yielded health authority-approved novel drugs with unique pharmacological signatures and mechanism(s) of action and AQH drainage microdevices for effectively and durably treating OHT. A unique nitric oxide-donating conjugate of latanoprost, an FP-receptor prostaglandin (PG; latanoprostene bunod), new rho kinase inhibitors (ripasudil; netarsudil), a novel non-PG EP2-receptor-selective agonist (omidenepag isopropyl), and a form of FP-receptor PG in a slow-release intracameral implant (Durysta) represent the additions to the pharmaceutical toolchest to mitigate the ravages of OHT. Despite these advances, early diagnosis of OHT and glaucoma still lags behind and would benefit from further concerted effort and attention.
Collapse
Affiliation(s)
- Najam A Sharif
- Eye-APC Duke-NUS Medical School, Singapore 169856, Singapore
- Singapore Eye Research Institute, Singapore 169856, Singapore
- Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center, Fort Worth, TX 76107, USA
- Department of Pharmacy Sciences, Creighton University, Omaha, NE 68178, USA
- Department of Pharmaceutical Sciences, College of Pharmacy and Health Sciences, Texas Southern University, Houston, TX 77004, USA
- Imperial College of Science and Technology, St. Mary's Campus, London SW7 2BX, UK
- Institute of Ophthalmology, University College London, London WC1E 6BT, UK
| |
Collapse
|
8
|
TRPV4 channels promote vascular permeability in retinal vascular disease. Exp Eye Res 2023; 228:109405. [PMID: 36773739 DOI: 10.1016/j.exer.2023.109405] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/11/2022] [Revised: 01/06/2023] [Accepted: 02/02/2023] [Indexed: 02/11/2023]
Abstract
This study aimed to determine the role of transient receptor potential vanilloid 4 (TRPV4), a calcium (Ca2+)-permeable cation channel, in the pathophysiology of retinal vascular disease. The retinal vein occlusion (RVO) murine model was created by irradiating retinal veins using lasers. TRPV4 expression and localization were evaluated in RVO mice retinas. In addition, we examined the effects of TRPV4 antagonists (RQ-00317310, HC-067047, GSK2193874, and GSK2798745) on retinal edema, blood flow, and ischemic areas in RVO mice. Furthermore, changes in the retinal expression of tumor necrosis factor (TNF)-α and aquaporin4 (AQP4) by RQ-00317310 were analyzed using Western blot. We also assessed the barrier integrity of epithelial cell monolayers using trans-endothelial electrical resistance (TEER) in Human Retinal Microvascular Endothelial Cells (HRMECs). The expression of TRPV4 was significantly increased and co-localized with glutamine synthetase (GS), a Müller glial marker, in the ganglion cell layer (GCL) of the RVO mice. Moreover, RQ-00317310 administration ameliorated the development of retinal edema and ischemia in RVO mice. In addition, the up regulation of TNF-α and down-regulation of AQP4 were lessened by the treatment with RQ-00317310. Treatment with GSK1016790A, a TRPV4 agonist, increased vascular permeability, while RQ-00317310 treatment decreased vascular endothelial growth factor (VEGF)- or TRPV4-induced retinal vascular hyperpermeability in HRMECs. These findings suggest that TRPV4 plays a role in the development of retinal edema and ischemia. Thus, TRPV4 could be a new therapeutic target against the pathological symptoms of retinal vascular diseases.
Collapse
|
9
|
Irnaten M, O’Brien CJ. Calcium-Signalling in Human Glaucoma Lamina Cribrosa Myofibroblasts. Int J Mol Sci 2023; 24:ijms24021287. [PMID: 36674805 PMCID: PMC9862249 DOI: 10.3390/ijms24021287] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/14/2022] [Revised: 12/20/2022] [Accepted: 01/01/2023] [Indexed: 01/11/2023] Open
Abstract
Glaucoma is one of the most common causes of treatable visual impairment in the developed world, affecting approximately 64 million people worldwide, some of whom will be bilaterally blind from irreversible optic nerve damage. The optic nerve head is a key site of damage in glaucoma where there is fibrosis of the connective tissue in the lamina cribrosa (LC) extracellular matrix. As a ubiquitous second messenger, calcium (Ca2+) can interact with various cellular proteins to regulate multiple physiological processes and contribute to a wide range of diseases, including cancer, fibrosis, and glaucoma. Our research has shown evidence of oxidative stress, mitochondrial dysfunction, an elevated expression of Ca2+ entry channels, Ca2+-dependent pumps and exchangers, and an abnormal rise in cytosolic Ca2+ in human glaucomatous LC fibroblast cells. We have evidence that this increase is dependent on Ca2+ entry channels located in the plasma membrane, and its release is from internal stores in the endoplasmic reticulum (ER), as well as from the mitochondria. Here, we summarize some of the molecular Ca2+-dependent mechanisms related to this abnormal Ca2+-signalling in human glaucoma LC cells, with a view toward identifying potential therapeutic targets for ongoing optic neuropathy.
Collapse
|
10
|
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.
Collapse
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.
| |
Collapse
|
11
|
Hulme L, Hochstetler A, Schwerk C, Schroten H, Ishikawa H, Tung CY, Perrin B, Blazer-Yost B. Characterization of TRPV4-mediated signaling pathways in an optimized human choroid plexus epithelial cell line. Am J Physiol Cell Physiol 2022; 323:C1823-C1842. [PMID: 35938676 PMCID: PMC9744646 DOI: 10.1152/ajpcell.00193.2022] [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: 05/09/2022] [Revised: 07/27/2022] [Accepted: 07/28/2022] [Indexed: 12/14/2022]
Abstract
The objectives of these studies were twofold: 1) to characterize the human choroid plexus papilloma (HIBCPP) cell line as a model of the blood-cerebrospinal fluid barrier (BCSFB) via morphology, tightness, and polarization of transporters in choroid plexus epithelia (CPe), and 2) to utilize Ussing-style electrophysiology to elucidate signaling pathways associated with the activation of the transient receptor potential vanilloid 4 (TRPV4) channel involved in cerebrospinal fluid (CSF) secretion. RT-PCR was implemented to determine gene expression of cell fate markers, junctional complex proteins, and transporters of interest. Scanning electron microscopy and confocal three-dimensional renderings of cultures grown on permeable supports were utilized to delineate the morphology of the brush border, junctional complexes, and polarization of key transporters. Electrophysiology was used to understand and explore TRPV4-mediated signaling in the HIBCPP cell line, considering both short-circuit current (Isc) and conductance responses. HIBCPP cells grown under optimized culture conditions exhibited minimal multilayering, developed an intermediate resistance monolayer, retained differentiation properties, and expressed, and correctly localized, junctional proteins and native transporters. We found that activation of TRPV4 resulted in a robust, multiphasic change in electrogenic ion flux and increase in conductance accompanied by substantial fluid secretion. This response appears to be modulated by a number of different effectors, implicating phospholipase C (PLC), protein kinase C (PKC), and phosphoinositide 3-kinase (PI3K) in TRPV4-mediated ion flux. The HIBCPP cell line is a representative model of the human BCSFB, which can be utilized for studies of transporter function, intracellular signaling, and regulation of CSF production.
Collapse
Affiliation(s)
- Louise Hulme
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana
| | - Alexandra Hochstetler
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana
| | - Christian Schwerk
- Department of Pediatrics, Pediatric Infectious Diseases, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Horst Schroten
- Department of Pediatrics, Pediatric Infectious Diseases, Medical Faculty Mannheim, Heidelberg University, Mannheim, Germany
| | - Hiroshi Ishikawa
- Department of Neurosurgery, Laboratory of Clinical Regenerative Medicine, University of Tsukuba, Ibaraki, Japan
| | - Chun-Yu Tung
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana
| | - Benjamin Perrin
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana
| | - Bonnie Blazer-Yost
- Department of Biology, Indiana University Purdue University Indianapolis, Indianapolis, Indiana
| |
Collapse
|
12
|
Asaoka R, Obana A, Murata H, Fujino Y, Omoto T, Aoki S, Muto S, Takayanagi Y, Inoue T, Tanito M. The Association Between Age and Systemic Variables and the Longitudinal Trend of Intraocular Pressure in a Large-Scale Health Examination Cohort. Invest Ophthalmol Vis Sci 2022; 63:22. [PMID: 36301531 PMCID: PMC9624273 DOI: 10.1167/iovs.63.11.22] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Purpose The detailed effects of age and systemic factors on intraocular pressure (IOP) have not been fully understood because of the lack of a large-scale longitudinal investigation. This study aimed to investigate the effect of various systemic factors on the longitudinal change of IOP. Methods There were a total of 20,909 eyes of 10,471 subjects from a health checkup cohort that were followed up for systemic factors: (i) age at baseline, (ii) sex, (iii) time series body mass index (BMI), (iv) time series smoking habits, (v) time series systolic and diastolic blood pressures (SBP and DBP), and (vi) time series 19 blood examinations (all of the time series data was acquired at each annual visit), along with IOP annually for at least 8 years. Then the longitudinal effect of the systemic factors on the change of IOP was investigated. Results IOP significantly decreased by −0.084 mm Hg/year. BMI, SBP, DBP, smoking habits, total triglyceride, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, and glycosylated hemoglobin A1c were not significantly associated with the change of IOP. Higher values of age, aspartate aminotransferase, hemoglobin, platelet, and calcium were suggested to be significantly associated with the decrease of IOP, whereas higher alanine aminotransferase, guanosine triphosphate, white blood cell count, red blood cell count, and female gender were significantly associated with the increase of IOP. Conclusions Age, aspartate aminotransferase, hemoglobin, platelet, calcium, alanine aminotransferase, guanosine triphosphate, white blood cell count, red blood cell count, and gender were the systemic variables significantly associated with the change of IOP.
Collapse
Affiliation(s)
- Ryo Asaoka
- Department of Ophthalmology, Seirei Hamamatsu General Hospital, Shizuoka, Hamamatsu, Japan
- Seirei Christopher University, Shizuoka, Hamamatsu, Japan
- Department of Ophthalmology, The University of Tokyo, Tokyo, Japan
- Nanovision Research Division, Research Institute of Electronics, Shizuoka University, Shizuoka Japan
- The Graduate School for the Creation of New Photonics Industries, Shizuoka Japan
| | - Akira Obana
- Department of Ophthalmology, Seirei Hamamatsu General Hospital, Shizuoka, Hamamatsu, Japan
- Hamamatsu BioPhotonics Innovation Chair, Institute for Medical Photonics Research, Preeminent Medical Photonics Education & Research Center, Hamamatsu University School of Medicine, Hamamatsu, Shizuoka, Japan
| | - Hiroshi Murata
- Department of Ophthalmology, The University of Tokyo, Tokyo, Japan
- Department of Ophthalmology, National Center for Global Health and Medicine, Shinjuku, Tokyo, Japan
| | - Yuri Fujino
- Department of Ophthalmology, Seirei Hamamatsu General Hospital, Shizuoka, Hamamatsu, Japan
- Department of Ophthalmology, Shimane University Faculty of Medicine, Izumo, Japan
| | - Takashi Omoto
- Department of Ophthalmology, The University of Tokyo, Tokyo, Japan
| | - Shuichiro Aoki
- Department of Ophthalmology, Sapporo City General Hospital, Sapporo, Japan
| | - Shigetaka Muto
- Seirei Center for Health Promotion and Preventive Medicine, Shizuoka, Hamamatsu, Japan
| | - Yuji Takayanagi
- Department of Ophthalmology, Seirei Hamamatsu General Hospital, Shizuoka, Hamamatsu, Japan
- Department of Ophthalmology, Shimane University Faculty of Medicine, Izumo, Japan
| | - Tatsuya Inoue
- Department of Ophthalmology and Micro-Technology, Yokohama City University, Kanagawa, Japan
| | - Masaki Tanito
- Department of Ophthalmology, Shimane University Faculty of Medicine, Izumo, Japan
| |
Collapse
|
13
|
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.
Collapse
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.
| |
Collapse
|
14
|
Chen S, Wang W, Cao Q, Wu S, Wang N, Ji L, Zhu W. Cationic Mechanosensitive Channels Mediate Trabecular Meshwork Responses to Cyclic Mechanical Stretch. Front Pharmacol 2022; 13:881286. [PMID: 35928263 PMCID: PMC9343793 DOI: 10.3389/fphar.2022.881286] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2022] [Accepted: 06/23/2022] [Indexed: 11/13/2022] Open
Abstract
The trabecular meshwork (TM) is responsible for intraocular pressure (IOP) homeostasis in the eye. The tissue senses IOP fluctuations and dynamically adapts to the mechanical changes to either increase or decrease aqueous humor outflow. Cationic mechanosensitive channels (CMCs) have been reported to play critical roles in mediating the TM responses to mechanical forces. However, how CMCs influence TM cellular function affect aqueous humor drainage is still elusive. In this study, human TM (HTM) cells were collected from a Chinese donor and subjected to cyclically equiaxial stretching with an amplitude of 20% at 1 Hz GsMTx4, a non-selective inhibitor for CMCs, was added to investigate the proteomic changes induced by CMCs in response to mechanical stretch of HTM. Gene ontology enrichment analysis demonstrated that inhibition of CMCs significantly influenced several biochemical pathways, including store-operated calcium channel activity, microtubule cytoskeleton polarity, toll-like receptor signaling pathway, and neuron cell fate specification. Through heatmap analysis, we grouped 148 differentially expressed proteins (DEPs) into 21 clusters and focused on four specific patterns associated with Ca2+ homeostasis, autophagy, cell cycle, and cell fate. Our results indicated that they might be the critical downstream signals of CMCs adapting to mechanical forces and mediating AH outflow.
Collapse
Affiliation(s)
- Susu Chen
- School of Pharmacy, Qingdao University, Qingdao, China
| | - Wenyan Wang
- Department of Clinical Pharmacy, The Second Hospital of Traditional Chinese Medicine of Huangdao District, Qingdao, China
| | - Qilong Cao
- Qingdao Haier Biotech Co.,Ltd., Qingdao, China
| | - Shen Wu
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital Eye Center, Capital Medical University, Beijing, China
| | - Ningli Wang
- Beijing Institute of Ophthalmology, Beijing Tongren Hospital Eye Center, Capital Medical University, Beijing, China
| | - Lixia Ji
- School of Pharmacy, Qingdao University, Qingdao, China
- *Correspondence: Wei Zhu, ; Lixia Ji,
| | - Wei Zhu
- School of Pharmacy, Qingdao University, Qingdao, China
- Beijing Advanced Innovation Center for Big Data-Based Precision Medicine, Beihang University and Capital Medical University, Beijing, China
- *Correspondence: Wei Zhu, ; Lixia Ji,
| |
Collapse
|
15
|
Beeken J, Mertens M, Stas N, Kessels S, Aerts L, Janssen B, Mussen F, Pinto S, Vennekens R, Rigo JM, Nguyen L, Brône B, Alpizar YA. Acute inhibition of transient receptor potential vanilloid-type 4 cation channel halts cytoskeletal dynamism in microglia. Glia 2022; 70:2157-2168. [PMID: 35809029 DOI: 10.1002/glia.24243] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/13/2022] [Revised: 06/23/2022] [Accepted: 06/27/2022] [Indexed: 01/04/2023]
Abstract
Microglia, the resident macrophages of the central nervous system, are highly motile cells that support brain development, provision neuronal signaling, and protect brain cells against damage. Proper microglial functioning requires constant cell movement and morphological changes. Interestingly, the transient receptor potential vanilloid 4 (TRPV4) channel, a calcium-permeable channel, is involved in hypoosmotic morphological changes of retinal microglia and regulates temperature-dependent movement of microglial cells both in vitro and in vivo. Despite the broad functions of TRPV4 and the recent findings stating a role for TRPV4 in microglial movement, little is known about how TRPV4 modulates cytoskeletal remodeling to promote changes of microglial motility. Here we show that acute inhibition of TRPV4, but not its constitutive absence in the Trpv4 KO cells, affects the morphology and motility of microglia in vitro. Using high-end confocal imaging techniques, we show a decrease in actin-rich filopodia and tubulin dynamics upon acute inhibition of TRPV4 in vitro. Furthermore, using acute brain slices we demonstrate that Trpv4 knockout microglia display lower ramification complexity, slower process extension speed and consequently smaller surveyed area. We conclude that TRPV4 inhibition triggers a shift in cytoskeleton remodeling of microglia influencing their migration and morphology.
Collapse
Affiliation(s)
- Jolien Beeken
- UHasselt, BIOMED, Diepenbeek, Belgium.,Université de Liège, GIGA-Stem-Cells, Liège, Belgium
| | | | | | | | | | | | | | - Silvia Pinto
- Laboratory of Ion Channel Research, VIB-KU Leuven, Leuven, Belgium
| | - Rudi Vennekens
- Laboratory of Ion Channel Research, VIB-KU Leuven, Leuven, Belgium
| | | | | | | | | |
Collapse
|
16
|
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.
Collapse
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.
| |
Collapse
|
17
|
Sharif NA. Degeneration of retina-brain components and connections in glaucoma: Disease causation and treatment options for eyesight preservation. CURRENT RESEARCH IN NEUROBIOLOGY 2022; 3:100037. [PMID: 36685768 PMCID: PMC9846481 DOI: 10.1016/j.crneur.2022.100037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/15/2022] [Revised: 03/30/2022] [Accepted: 04/01/2022] [Indexed: 01/25/2023] Open
Abstract
Eyesight is the most important of our sensory systems for optimal daily activities and overall survival. Patients who experience visual impairment due to elevated intraocular pressure (IOP) are often those afflicted with primary open-angle glaucoma (POAG) which slowly robs them of their vision unless treatment is administered soon after diagnosis. The hallmark features of POAG and other forms of glaucoma are damaged optic nerve, retinal ganglion cell (RGC) loss and atrophied RGC axons connecting to various brain regions associated with receipt of visual input from the eyes and eventual decoding and perception of images in the visual cortex. Even though increased IOP is the major risk factor for POAG, the disease is caused by many injurious chemicals and events that progress slowly within all components of the eye-brain visual axis. Lowering of IOP mitigates the damage to some extent with existing drugs, surgical and device implantation therapeutic interventions. However, since multifactorial degenerative processes occur during aging and with glaucomatous optic neuropathy, different forms of neuroprotective, nutraceutical and electroceutical regenerative and revitalizing agents and processes are being considered to combat these eye-brain disorders. These aspects form the basis of this short review article.
Collapse
Affiliation(s)
- Najam A. Sharif
- Duke-National University of Singapore Medical School, Singapore,Singapore Eye Research Institute (SERI), Singapore,Department of Pharmacology and Neuroscience, University of North Texas Health Sciences Center, Fort Worth, Texas, USA,Department of Pharmaceutical Sciences, Texas Southern University, Houston, TX, USA,Department of Surgery & Cancer, Imperial College of Science and Technology, St. Mary's Campus, London, UK,Department of Pharmacy Sciences, School of School of Pharmacy and Health Professions, Creighton University, Omaha, NE, USA,Ophthalmology Innovation Center, Santen Incorporated, 6401 Hollis Street (Suite #125), Emeryville, CA, 94608, USA,Ophthalmology Innovation Center, Santen Incorporated, 6401 Hollis Street (Suite #125), Emeryville, CA, 94608, USA.
| |
Collapse
|
18
|
Jo AO, Lakk M, Rudzitis CN, Križaj D. TRPV4 and TRPC1 channels mediate the response to tensile strain in mouse Müller cells. Cell Calcium 2022; 104:102588. [PMID: 35398674 PMCID: PMC9119919 DOI: 10.1016/j.ceca.2022.102588] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/11/2022] [Revised: 03/10/2022] [Accepted: 04/01/2022] [Indexed: 11/24/2022]
Abstract
Müller glia, a pillar of metabolic, volume regulatory and immune/inflammatory signaling in the mammalian retina, are among the earliest responders to mechanical stressors in the eye. Ocular trauma, edema, detachment and glaucoma evoke early inflammatory activation of Müller cells yet the identity of their mechanotransducers and signaling mechanisms downstream remains unknown. Here, we investigate expression of genes that encode putative stretch-activated calcium channels (SACs) in mouse Müller cells and study their responses to dynamical tensile loading in cells loaded with a calcium indicator dye. Transcript levels in purified glia were Trpc1>Piezo1>Trpv2>Trpv4>>Trpv1>Trpa1. Cyclic radial deformation of matrix-coated substrates produced dose-dependent increases in [Ca2+]i that were suppressed by the TRPV4 channel antagonist HC-067047 and by ablation of the Trpv4 gene. Stretch-evoked calcium responses were also reduced by knockdown and pharmacological inhibition of TRPC1 channels whereas the TRPV2 inhibitor tranilast had no effect. These data demonstrate that Müller cells are intrinsically mechanosensitive, with the response to tensile loading mediated through synergistic activation of TRPV4 and TRPC1 channels. Coupling between mechanical stress and Müller Ca2+ homeostasis has treatment implications, since many neuronal injury paradigms in the retina involve calcium dysregulation associated with inflammatory and immune signaling.
Collapse
Affiliation(s)
- Andrew O Jo
- 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
| | - Christopher N Rudzitis
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132; Interdepartmental Program in Neuroscience
| | - David Križaj
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132; Interdepartmental Program in Neuroscience; Department of Neurobiology, University of Utah, Salt Lake City, UT 84112; Department of Bioengineering, University of Utah, Salt Lake City, UT 84112.
| |
Collapse
|
19
|
Statins Inhibit the Gliosis of MIO-M1, a Müller Glial Cell Line Induced by TRPV4 Activation. Int J Mol Sci 2022; 23:ijms23095190. [PMID: 35563594 PMCID: PMC9100994 DOI: 10.3390/ijms23095190] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/19/2022] [Revised: 05/03/2022] [Accepted: 05/04/2022] [Indexed: 11/17/2022] Open
Abstract
We characterized Müller cell gliosis induced by the activation of transient receptor potential vanilloid-type 4 (TRPV4) and assessed whether statins could modulate the gliosis. The human Müller cell line, MIO-M1, was used to analyze the gliosis caused by glaucomatous stimulation. To induce Müller gliosis in MIO-M1 cells, GSK101 was used to activate TRPV4, and Müller gliosis was evaluated by analyzing vimentin, nestin, and glial fibrillary acidic protein (GFAP) expression. The expression level of TNF-α was determined by ELISA. To evaluate the GSK101 activation of the NF-κB pathway, p65 phosphorylation was measured by Western blotting, and the nuclear translocation of p65 and IκBα phosphorylation were assessed by immunostaining. To assess the effect of statins on MIO-M1 gliosis, cells were pretreated for 24 h with statins before GSK101 treatment. Vimentin, nestin, and GFAP expression were upregulated by GSK101, while statins effectively inhibited them. The expression of TNF-α was increased by GSK101. The phosphorylation and nuclear translocation of p65 and IκBα phosphorylation, which occurs prior to p65 activation, were induced. Statins suppressed the GSK101-mediated phosphorylation of IκBα and p65 translocation. Statins can mitigate gliosis in the human Müller cell line. Because TRPV4 activation in Müller cells reflects glaucoma pathophysiology, statins may have the potential to prevent RGC death.
Collapse
|
20
|
Combined drug triads for synergic neuroprotection in retinal degeneration. Biomed Pharmacother 2022; 149:112911. [DOI: 10.1016/j.biopha.2022.112911] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2022] [Revised: 03/28/2022] [Accepted: 03/29/2022] [Indexed: 11/23/2022] Open
|
21
|
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.
Collapse
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
| |
Collapse
|
22
|
Ma L, Liu X, Liu Q, Jin S, Chang H, Liu H. The Roles of Transient Receptor Potential Ion Channels in Pathologies of Glaucoma. Front Physiol 2022; 13:806786. [PMID: 35185615 PMCID: PMC8850928 DOI: 10.3389/fphys.2022.806786] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2021] [Accepted: 01/03/2022] [Indexed: 11/13/2022] Open
Abstract
Transient receptor ion potential (TRP) channels are a cluster of non-selective cation channels present on cell membranes. They are important mediators of sensory signals to regulate cellular functions and signaling pathways. Alterations and dysfunction of these channels could disrupt physiological processes, thus leading to a broad array of disorders, such as cardiovascular, renal and nervous system diseases. These effects position them as potential targets for drug design and treatment. Because TRP channels can mediate processes such as mechanical conduction, osmotic pressure, and oxidative stress, they have been studied in the context of glaucoma. Glaucoma is an irreversible blinding eye disease caused by an intermittent or sustained increase in intraocular pressure (IOP), which results in the apoptosis of retinal ganglion cells (RGCs), optic nerve atrophy and eventually visual field defects. An increasing number of studies have documented that various TRP subfamilies are abundantly expressed in ocular structures, including the cornea, lens, ciliary body (CB), trabecular meshwork (TM) and retina. In alignment with these findings, there is also mounting evidence supporting the potential role of the TRP family in glaucoma progression. Therefore, it is of great interest and clinical significance to gain an increased understanding of these channels, which in turn could shed more light on the identification of new therapeutic targets for glaucoma. Moreover, this role is not understood completely to date, and whether the activation of TRP channels contributes to glaucoma, or instead aggravates progression, needs to be explored. In this manuscript, we aim to provide a comprehensive overview of recent research on TRP channels in glaucoma and to suggest novel targets for future therapeutic interventions in glaucoma.
Collapse
Affiliation(s)
- Lin Ma
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Xin Liu
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Qing Liu
- Shenzhen Key Laboratory of Viral Vectors for Biomedicine, Chinese Academy of Sciences, Shenzhen Institute of Advanced Technology, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, The Brain Cognition and Brain Disease Institute, Shenzhen, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Sen Jin
- Shenzhen Key Laboratory of Viral Vectors for Biomedicine, Chinese Academy of Sciences, Shenzhen Institute of Advanced Technology, Shenzhen-Hong Kong Institute of Brain Science-Shenzhen Fundamental Research Institutions, The Brain Cognition and Brain Disease Institute, Shenzhen, China
- University of Chinese Academy of Sciences, Beijing, China
| | - Heng Chang
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
| | - Haixia Liu
- Department of Ophthalmology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan, China
- *Correspondence: Haixia Liu,
| |
Collapse
|
23
|
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.
Collapse
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
| |
Collapse
|
24
|
Delamere NA, Shahidullah M. Ion Transport Regulation by TRPV4 and TRPV1 in Lens and Ciliary Epithelium. Front Physiol 2022; 12:834916. [PMID: 35173627 PMCID: PMC8841554 DOI: 10.3389/fphys.2021.834916] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Accepted: 12/27/2021] [Indexed: 02/02/2023] Open
Abstract
Aside from a monolayer of epithelium at the anterior surface, the lens is formed by tightly compressed multilayers of fiber cells, most of which are highly differentiated and have a limited capacity for ion transport. Only the anterior monolayer of epithelial cells has high Na, K-ATPase activity. Because the cells are extensively coupled, the lens resembles a syncytium and sodium-potassium homeostasis of the entire structure is largely dependent on ion transport by the epithelium. Here we describe recent studies that suggest TRPV4 and TRPV1 ion channels activate signaling pathways that play an important role in matching epithelial ion transport activity with needs of the lens cell mass. A TRPV4 feedback loop senses swelling in the fiber mass and increases Na, K-ATPase activity to compensate. TRPV4 channel activation in the epithelium triggers opening of connexin hemichannels, allowing the release of ATP that stimulates purinergic receptors in the epithelium and results in the activation of Src family tyrosine kinases (SFKs) and SFK-dependent increase of Na, K-ATPase activity. A separate TRPV1 feedback loop senses shrinkage in the fiber mass and increases NKCC1 activity to compensate. TRPV1 activation causes calcium-dependent activation of a signaling cascade in the lens epithelium that involves PI3 kinase, ERK, Akt and WNK. TRPV4 and TRPV1 channels are also evident in the ciliary body where Na, K-ATPase is localized on one side of a bilayer in which two different cell types, non-pigmented and pigmented ciliary epithelium, function in a coordinated manner to secrete aqueous humor. TRPV4 and TRPV1 may have a role in maintenance of cell volume homeostasis as ions and water move through the bilayer.
Collapse
|
25
|
Nguyen TN, Siddiqui G, Veldhuis NA, Poole DP. Diverse Roles of TRPV4 in Macrophages: A Need for Unbiased Profiling. Front Immunol 2022; 12:828115. [PMID: 35126384 PMCID: PMC8811046 DOI: 10.3389/fimmu.2021.828115] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Accepted: 12/24/2021] [Indexed: 12/27/2022] Open
Abstract
Transient receptor potential vanilloid 4 (TRPV4) is a non-selective mechanosensitive ion channel expressed by various macrophage populations. Recent reports have characterized the role of TRPV4 in shaping the activity and phenotype of macrophages to influence the innate immune response to pathogen exposure and inflammation. TRPV4 has been studied extensively in the context of inflammation and inflammatory pain. Although TRPV4 activity has been generally described as pro-inflammatory, emerging evidence suggests a more complex role where this channel may also contribute to anti-inflammatory activities. However, detailed understanding of how TRPV4 may influence the initiation, maintenance, and resolution of inflammatory disease remains limited. This review highlights recent insights into the cellular processes through which TRPV4 contributes to pathological conditions and immune processes, with a focus on macrophage biology. The potential use of high-throughput and omics methods as an unbiased approach for studying the functional outcomes of TRPV4 activation is also discussed.
Collapse
Affiliation(s)
- Thanh-Nhan Nguyen
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- Australian Research Council (ARC) Centre of Excellence in Convergent Bio-Nano Science & Technology, Monash University, Parkville, VIC, Australia
| | - Ghizal Siddiqui
- Drug Delivery, Disposition and Dynamics Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
| | - Nicholas A. Veldhuis
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- Australian Research Council (ARC) Centre of Excellence in Convergent Bio-Nano Science & Technology, Monash University, Parkville, VIC, Australia
- *Correspondence: Daniel P. Poole, ; Nicholas A. Veldhuis,
| | - Daniel P. Poole
- Drug Discovery Biology Theme, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, VIC, Australia
- Australian Research Council (ARC) Centre of Excellence in Convergent Bio-Nano Science & Technology, Monash University, Parkville, VIC, Australia
- *Correspondence: Daniel P. Poole, ; Nicholas A. Veldhuis,
| |
Collapse
|
26
|
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.
Collapse
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
| |
Collapse
|
27
|
Li Q, Cheng Y, Zhang S, Sun X, Wu J. TRPV4-induced Müller cell gliosis and TNF-α elevation-mediated retinal ganglion cell apoptosis in glaucomatous rats via JAK2/STAT3/NF-κB pathway. J Neuroinflammation 2021; 18:271. [PMID: 34789280 PMCID: PMC8596927 DOI: 10.1186/s12974-021-02315-8] [Citation(s) in RCA: 29] [Impact Index Per Article: 9.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2021] [Accepted: 11/01/2021] [Indexed: 01/22/2023] Open
Abstract
Background Glaucoma, the leading cause of irreversible blindness worldwide, is a type of retinal disease characterized by the selective death of retinal ganglion cells (RGCs). However, the pathogenesis of glaucoma has not been fully elucidated. Transient receptor potential vanilloid 4 (TRPV4) is a pressure-sensitive and calcium-permeable cation channel. TRPV4 is widely distributed in the retina and its sustained activation leads to RGC death; indicating that TRPV4 may be a possible target for glaucoma treatment. Here, we investigated the effects of TRPV4 on RGC apoptosis in a rat model of chronic ocular hypertension (COH), then examined the mechanism underlying these effects. Methods The COH model was established by injection of micro-magnetic beads into the anterior chamber of adult male rats. The expression levels of TRPV4, glial fibrillary acidic protein, and inflammatory factors were assessed by immunohistochemistry and immunoblotting. RGC apoptosis and visual dysfunction were evaluated by TUNEL assay and photopic negative response. Functional expression of TRPV4 was examined by electrophysiology and calcium imaging. Real-time polymerase chain reaction and immunoblotting were employed to investigate the molecular mechanism underlying the effects of TRPV4 on tumor necrosis factor-α (TNF-α) release. Results We found that TRPV4 played an essential role in glaucoma, such that high levels of TRPV4 expression were associated with elevated intraocular pressure. Furthermore, TRPV4 activation was involved in glaucoma-induced RGC apoptosis and RGC-related reductions in visual function. Mechanistic investigation demonstrated that TRPV4 activation led to enhanced Müller cell gliosis and TNF-α release via the JAK2/STAT3/NF-kB pathway, while TRPV4 inhibition could reverse these effects. Finally, TRPV4 activation could lead to elevated expression of TNF receptor 1 in RGCs, while inhibition of TNF-α could reduce TRPV4-mediated RGC apoptosis. Conclusions TRPV4 activation induces Müller cell gliosis and TNF-α elevation via the JAK2/STAT3/NF-κB pathway, which may exacerbate RGC apoptosis in glaucoma; these results suggest that TRPV4 can serve as a therapeutic target in glaucoma treatment. Supplementary Information The online version contains supplementary material available at 10.1186/s12974-021-02315-8.
Collapse
Affiliation(s)
- Qian Li
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, National Health Commission, #83 Fenyang Road, 200031, Shanghai, China
| | - Yun Cheng
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, National Health Commission, #83 Fenyang Road, 200031, Shanghai, China
| | - Shenghai Zhang
- Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China.,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, National Health Commission, #83 Fenyang Road, 200031, Shanghai, China
| | - Xinghuai Sun
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China. .,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China. .,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China. .,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, National Health Commission, #83 Fenyang Road, 200031, Shanghai, China.
| | - Jihong Wu
- Eye Institute, Eye and ENT Hospital, College of Medicine, Fudan University, Shanghai, China. .,Shanghai Key Laboratory of Visual Impairment and Restoration, Science and Technology Commission of Shanghai Municipality, Shanghai, China. .,NHC Key Laboratory of Myopia, Fudan University, Shanghai, China. .,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, National Health Commission, #83 Fenyang Road, 200031, Shanghai, China.
| |
Collapse
|
28
|
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.
Collapse
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.
| |
Collapse
|
29
|
Uchida T, Shimizu S, Yamagishi R, Tokuoka SM, Kita Y, Sakata R, Honjo M, Aihara M. TRPV4 is activated by mechanical stimulation to induce prostaglandins release in trabecular meshwork, lowering intraocular pressure. PLoS One 2021; 16:e0258911. [PMID: 34673834 PMCID: PMC8530296 DOI: 10.1371/journal.pone.0258911] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Accepted: 10/07/2021] [Indexed: 11/25/2022] Open
Abstract
Trabecular meshwork constitutes the conventional outflow pathway and controls intraocular pressure by regulating aqueous outflow. Mechanical stimulation has been studied as one of the triggers to regulate aqueous outflow in trabecular meshwork, but it is not well understood. We investigated that how transient receptor potential cation channel subfamily V member 4 (TRPV4) functions in human trabecular meshwork cells (HTMC) and affects intraocular pressure (IOP). HTMC were treated with TRPV4 siRNA, followed by incubation for 24 hours. We confirmed the suppression of TRPV4 mRNA expression and the reduction of Ca2+ influx by the TRPV4 agonist GSK1016790A in TRPV4 siRNA-treated HTMC. TRPV4 siRNA-treated HTMC exhibited a significant reduction in Ca2+ influx and production of arachidonic acid and prostaglandin (PG) E2 induced by mechanical stretch, and direct activation of TRPV4 by GSK1016790A increased production of arachidonic acid, PGE2, and PGD2 and inhibited gel contraction. Furthermore, TRPV4-deficient mice had higher IOP than wild-type mice, and GSK1016790A administration lowered IOP. These results suggest that TRPV4 mediates the cellular response induced by trabecular meshwork stretch, leading to IOP reduction through the production of prostaglandins and inhibition of cell contraction. Targeting TRPV4 may have therapeutic benefits that lead to lowering IOP in glaucoma patients.
Collapse
Affiliation(s)
- Takatoshi Uchida
- Department of Ophthalmology, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
- Senju Laboratory of Ocular Science, Senju Pharmaceutical Co., Ltd., Kobe, Japan
| | - Shota Shimizu
- Department of Ophthalmology, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
- Senju Laboratory of Ocular Science, Senju Pharmaceutical Co., Ltd., Kobe, Japan
| | - Reiko Yamagishi
- Department of Ophthalmology, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
| | - Suzumi M. Tokuoka
- Department of Lipidomics, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
| | - Yoshihiro Kita
- Department of Lipidomics, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
- Life Science Core Facility, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
| | - Rei Sakata
- Department of Ophthalmology, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
| | - Megumi Honjo
- Department of Ophthalmology, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
| | - Makoto Aihara
- Department of Ophthalmology, Graduate School of Medicine, the University of Tokyo, Tokyo, Japan
- * E-mail:
| |
Collapse
|
30
|
Lamont HC, Masood I, Grover LM, El Haj AJ, Hill LJ. Fundamental Biomaterial Considerations in the Development of a 3D Model Representative of Primary Open Angle Glaucoma. Bioengineering (Basel) 2021; 8:bioengineering8110147. [PMID: 34821713 PMCID: PMC8615171 DOI: 10.3390/bioengineering8110147] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2021] [Revised: 10/15/2021] [Accepted: 10/17/2021] [Indexed: 12/12/2022] Open
Abstract
Glaucoma is a leading cause of irreversible blindness globally, with primary open angle glaucoma (POAG) being the most common subset. Raised intraocular pressure is an important risk factor for POAG and is caused by a reduction in aqueous humour (AqH) outflow due to dysfunctional cellular and matrix dynamics in the eye’s main drainage site, the trabecular meshwork (TM) and Schlemm’s canal (SC). The TM/SC are highly specialised tissues that regulate AqH outflow; however, their exact mechanisms of AqH outflow control are still not fully understood. Emulating physiologically relevant 3D TM/S in vitro models poses challenges to accurately mimic the complex biophysical and biochemical cues that take place in healthy and glaucomatous TM/SC in vivo. With development of such models still in its infancy, there is a clear need for more well-defined approaches that will accurately contrast the two central regions that become dysfunctional in POAG; the juxtacanalicular tissue (JCT) region of the TM and inner wall endothelia of the Schlemm’s canal (eSC). This review will discuss the unique biological and biomechanical characteristics that are thought to influence AqH outflow and POAG progression. Further consideration into fundamental biomaterial attributes for the formation of a biomimetic POAG/AqH outflow model will also be explored for future success in pre-clinical drug discovery and disease translation.
Collapse
Affiliation(s)
- Hannah C. Lamont
- School of Biomedical Sciences, Institute of Clinical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (H.C.L.); (I.M.)
- School of Chemical Engineering, Healthcare Technologies Institute, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (L.M.G.); (A.J.E.H.)
| | - Imran Masood
- School of Biomedical Sciences, Institute of Clinical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (H.C.L.); (I.M.)
| | - Liam M. Grover
- School of Chemical Engineering, Healthcare Technologies Institute, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (L.M.G.); (A.J.E.H.)
| | - Alicia J. El Haj
- School of Chemical Engineering, Healthcare Technologies Institute, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (L.M.G.); (A.J.E.H.)
| | - Lisa J. Hill
- School of Biomedical Sciences, Institute of Clinical Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK; (H.C.L.); (I.M.)
- Correspondence:
| |
Collapse
|
31
|
Toft-Bertelsen TL, MacAulay N. TRPing on Cell Swelling - TRPV4 Senses It. Front Immunol 2021; 12:730982. [PMID: 34616399 PMCID: PMC8488219 DOI: 10.3389/fimmu.2021.730982] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/25/2021] [Accepted: 08/30/2021] [Indexed: 11/29/2022] Open
Abstract
The transient receptor potential vanilloid 4 channel (TRPV4) is a non-selective cation channel that is widely expressed and activated by a range of stimuli. Amongst these stimuli, changes in cell volume feature as a prominent regulator of TRPV4 activity with cell swelling leading to channel activation. In experimental settings based on abrupt introduction of large osmotic gradients, TRPV4 activation requires co-expression of an aquaporin (AQP) to facilitate such cell swelling. However, TRPV4 readily responds to cell volume increase irrespectively of the molecular mechanism underlying the cell swelling and can, as such, be considered a sensor of increased cell volume. In this review, we will discuss the proposed events underlying the molecular coupling from cell swelling to channel activation and present the evidence of direct versus indirect swelling-activation of TRPV4. With this summary of the current knowledge of TRPV4 and its ability to sense cell volume changes, we hope to stimulate further experimental efforts in this area of research to clarify TRPV4’s role in physiology and pathophysiology.
Collapse
Affiliation(s)
| | - Nanna MacAulay
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| |
Collapse
|
32
|
Sharif NA. Therapeutic Drugs and Devices for Tackling Ocular Hypertension and Glaucoma, and Need for Neuroprotection and Cytoprotective Therapies. Front Pharmacol 2021; 12:729249. [PMID: 34603044 PMCID: PMC8484316 DOI: 10.3389/fphar.2021.729249] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2021] [Accepted: 08/18/2021] [Indexed: 12/11/2022] Open
Abstract
Damage to the optic nerve and the death of associated retinal ganglion cells (RGCs) by elevated intraocular pressure (IOP), also known as glaucoma, is responsible for visual impairment and blindness in millions of people worldwide. The ocular hypertension (OHT) and the deleterious mechanical forces it exerts at the back of the eye, at the level of the optic nerve head/optic disc and lamina cribosa, is the only modifiable risk factor associated with glaucoma that can be treated. The elevated IOP occurs due to the inability of accumulated aqueous humor (AQH) to egress from the anterior chamber of the eye due to occlusion of the major outflow pathway, the trabecular meshwork (TM) and Schlemm’s canal (SC). Several different classes of pharmaceutical agents, surgical techniques and implantable devices have been developed to lower and control IOP. First-line drugs to promote AQH outflow via the uveoscleral outflow pathway include FP-receptor prostaglandin (PG) agonists (e.g., latanoprost, travoprost and tafluprost) and a novel non-PG EP2-receptor agonist (omidenepag isopropyl, Eybelis®). TM/SC outflow enhancing drugs are also effective ocular hypotensive agents (e.g., rho kinase inhibitors like ripasudil and netarsudil; and latanoprostene bunod, a conjugate of a nitric oxide donor and latanoprost). One of the most effective anterior chamber AQH microshunt devices is the Preserflo® microshunt which can lower IOP down to 10–13 mmHg. Other IOP-lowering drugs and devices on the horizon will be also discussed. Additionally, since elevated IOP is only one of many risk factors for development of glaucomatous optic neuropathy, a treatise of the role of inflammatory neurodegeneration of the optic nerve and retinal ganglion cells and appropriate neuroprotective strategies to mitigate this disease will also be reviewed and discussed.
Collapse
Affiliation(s)
- Najam A Sharif
- Global Alliances and External Research, Ophthalmology Innovation Center, Santen Inc., Emeryville, CA, United States
| |
Collapse
|
33
|
Cappelli HC, Guarino BD, Kanugula AK, Adapala RK, Perera V, Smith MA, Paruchuri S, Thodeti CK. Transient receptor potential vanilloid 4 channel deletion regulates pathological but not developmental retinal angiogenesis. J Cell Physiol 2021; 236:3770-3779. [PMID: 33078410 PMCID: PMC7920906 DOI: 10.1002/jcp.30116] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2019] [Revised: 10/07/2020] [Accepted: 10/09/2020] [Indexed: 01/08/2023]
Abstract
Transient receptor potential vanilloid 4 (TRPV4) channels are mechanosensitive ion channels that regulate systemic endothelial cell (EC) functions such as vasodilation, permeability, and angiogenesis. TRPV4 is expressed in retinal ganglion cells, Müller glia, pigment epithelium, microvascular ECs, and modulates cell volume regulation, calcium homeostasis, and survival. TRPV4-mediated physiological or pathological retinal angiogenesis remains poorly understood. Here, we demonstrate that TRPV4 is expressed, functional, and mechanosensitive in retinal ECs. The genetic deletion of TRPV4 did not affect postnatal developmental angiogenesis but increased pathological neovascularization in response to oxygen-induced retinopathy (OIR). Retinal vessels from TRPV4 knockout mice subjected to OIR exhibited neovascular tufts that projected into the vitreous humor and displayed reduced pericyte coverage compared with wild-type mice. These results suggest that TRPV4 is a regulator of retinal angiogenesis, its deletion augments pathological retinal angiogenesis, and that TRPV4 could be a novel target for the development of therapies against neovascular ocular diseases.
Collapse
Affiliation(s)
- Holly C. Cappelli
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272
- School of Biomedical Sciences, Kent State University, Kent, OH 44240
| | - Brianna D. Guarino
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272
| | - Anantha K. Kanugula
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272
| | - Ravi K. Adapala
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272
- School of Biomedical Sciences, Kent State University, Kent, OH 44240
| | - Vidushani Perera
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272
| | - Matthew A. Smith
- Department of Pharmaceutical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272
- Rebbeca D. Considine Research Institute, Akron Children’s Hospital, Akron, OH 44302
| | | | - Charles K. Thodeti
- Department of Integrative Medical Sciences, Northeast Ohio Medical University, Rootstown, OH 44272
- School of Biomedical Sciences, Kent State University, Kent, OH 44240
| |
Collapse
|
34
|
Serum Calcium Level as a Useful Surrogate for Risk of Elevated Intraocular Pressure. J Clin Med 2021; 10:jcm10091839. [PMID: 33922687 PMCID: PMC8122949 DOI: 10.3390/jcm10091839] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2021] [Revised: 04/19/2021] [Accepted: 04/21/2021] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Uncontrolled intraocular pressure (IOP) plays a principal role in the deterioration of glaucoma, and the intraocular pressure is also accepted as the most important modifiable factor. Calcium ion has been found to play a vital role in regulating the resistance of the trabecular meshwork in humans. However, the relationship between serum total calcium and IOP has not been well-established. METHODS We investigated the association between serum total calcium and the IOP in a large population (14,037 eligible participants, consisting of 7712 men and 6325 women, were included) at the Tri-Service General Hospital from 2010 to 2016. Several models of covariate adjustments associated with IOP were designed. Univariate and multivariate regression analysis was performed for gender differences in the association between the serum total calcium level and IOP. RESULTS There was a significant relationship between serum total calcium levels and IOP in women and men with a β coefficient of 0.050 (95% confidence interval (CI), 0.030-0.069) and 0.025 (95%CI, 0.007-0.043). Notably, participants in the highest tertiles of serum total calcium levels had significantly higher IOP, in both the male and female participants. CONCLUSIONS Our study shows that IOP is significantly associated with serum total calcium levels in a large Asian population. This study supports the notion that serum total calcium may play an important role in groups at high risk for elevated IOP.
Collapse
|
35
|
Patel PD, Chen YL, Kasetti RB, Maddineni P, Mayhew W, Millar JC, Ellis DZ, Sonkusare SK, Zode GS. Impaired TRPV4-eNOS signaling in trabecular meshwork elevates intraocular pressure in glaucoma. Proc Natl Acad Sci U S A 2021; 118:e2022461118. [PMID: 33853948 PMCID: PMC8072326 DOI: 10.1073/pnas.2022461118] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Primary Open Angle Glaucoma (POAG) is the most common form of glaucoma that leads to irreversible vision loss. Dysfunction of trabecular meshwork (TM) tissue, a major regulator of aqueous humor (AH) outflow resistance, is associated with intraocular pressure (IOP) elevation in POAG. However, the underlying pathological mechanisms of TM dysfunction in POAG remain elusive. In this regard, transient receptor potential vanilloid 4 (TRPV4) cation channels are known to be important Ca2+ entry pathways in multiple cell types. Here, we provide direct evidence supporting Ca2+ entry through TRPV4 channels in human TM cells and show that TRPV4 channels in TM cells can be activated by increased fluid flow/shear stress. TM-specific TRPV4 channel knockout in mice elevated IOP, supporting a crucial role for TRPV4 channels in IOP regulation. Pharmacological activation of TRPV4 channels in mouse eyes also improved AH outflow facility and lowered IOP. Importantly, TRPV4 channels activated endothelial nitric oxide synthase (eNOS) in TM cells, and loss of eNOS abrogated TRPV4-induced lowering of IOP. Remarkably, TRPV4-eNOS signaling was significantly more pronounced in TM cells compared to Schlemm's canal cells. Furthermore, glaucomatous human TM cells show impaired activity of TRPV4 channels and disrupted TRPV4-eNOS signaling. Flow/shear stress activation of TRPV4 channels and subsequent NO release were also impaired in glaucomatous primary human TM cells. Together, our studies demonstrate a central role for TRPV4-eNOS signaling in IOP regulation. Our results also provide evidence that impaired TRPV4 channel activity in TM cells contributes to TM dysfunction and elevated IOP in glaucoma.
Collapse
Affiliation(s)
- Pinkal D Patel
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107
| | - Yen-Lin Chen
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908
| | - Ramesh B Kasetti
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107
| | - Prabhavathi Maddineni
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107
| | - William Mayhew
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107
| | - J Cameron Millar
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107
| | - Dorette Z Ellis
- Department of Pharmaceutical Sciences, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107
| | - Swapnil K Sonkusare
- Robert M. Berne Cardiovascular Research Center, University of Virginia, Charlottesville, VA 22908;
- Molecular Physiology and Biological Physics, University of Virginia School of Medicine, Charlottesville, VA 22908
| | - Gulab S Zode
- Department of Pharmacology and Neuroscience, North Texas Eye Research Institute, University of North Texas Health Science Center at Fort Worth, Fort Worth, TX 76107;
| |
Collapse
|
36
|
Lakk M, Križaj D. TRPV4-Rho signaling drives cytoskeletal and focal adhesion remodeling in trabecular meshwork cells. Am J Physiol Cell Physiol 2021; 320:C1013-C1030. [PMID: 33788628 PMCID: PMC8285634 DOI: 10.1152/ajpcell.00599.2020] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
Intraocular pressure (IOP) is dynamically regulated by the trabecular meshwork (TM), a mechanosensitive tissue that protects the eye from injury through dynamic regulation of aqueous humor flow. TM compensates for mechanical stress impelled by chronic IOP elevations through increased actin polymerization, tissue stiffness, and contractility. This process has been associated with open angle glaucoma; however, the mechanisms that link mechanical stress to pathological cytoskeletal remodeling downstream from the mechanotransducers remain poorly understood. We used fluorescence imaging and biochemical analyses to investigate cytoskeletal and focal adhesion remodeling in human TM cells stimulated with physiological strains. Mechanical stretch promoted F-actin polymerization, increased the number and size of focal adhesions, and stimulated the activation of the Rho-associated protein kinase (ROCK). Stretch-induced activation of the small GTPase Ras homolog family member A (RhoA), and tyrosine phosphorylations of focal adhesion proteins paxillin, focal adhesion kinase (FAK), vinculin, and zyxin were time dependently inhibited by ROCK inhibitor trans-4-[(1R)-1-aminoethyl]-N-4-pyridinylcyclohexanecarboxamide dihydrochloride (Y-27632), and by HC-067047, an antagonist of transient receptor potential vanilloid 4 (TRPV4) channels. Both TRPV4 and ROCK activation were required for zyxin translocation and increase in the number/size of focal adhesions in stretched cells. Y-27632 blocked actin polymerization without affecting calcium influx induced by membrane stretch and the TRPV4 agonist GSK1016790A. These results reveal that mechanical tuning of TM cells requires parallel activation of TRPV4, integrins, and ROCK, with chronic stress leading to sustained remodeling of the cytoskeleton and focal complexes.
Collapse
Affiliation(s)
- Monika Lakk
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah
| | - David Križaj
- Department of Ophthalmology and Visual Sciences, University of Utah, Salt Lake City, Utah.,Department of Bioengineering, University of Utah, Salt Lake City, Utah.,Department of Neurobiology, University of Utah, Salt Lake City, Utah
| |
Collapse
|
37
|
Llorián-Salvador M, Barabas P, Byrne EM, Lechner J, Augustine J, Curtis TM, Chen M, Xu H. VEGF-B Is an Autocrine Gliotrophic Factor for Müller Cells under Pathologic Conditions. Invest Ophthalmol Vis Sci 2021; 61:35. [PMID: 32945843 PMCID: PMC7509798 DOI: 10.1167/iovs.61.11.35] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Purpose Müller glia are important in retinal health and disease and are a major source of retinal VEGF-A. Of the different VEGF family members, the role of VEGF-A in retinal health and disease has been studied extensively. The potential contribution of other VEGF family members to retinal pathophysiology, however, remains poorly defined. This study aimed to understand the role of VEGF-B in Müller cell pathophysiology. Methods The expression of different VEGFs and their receptors in human MIO-M1 and mouse QMMuC-1 Müller cell lines and primary murine Müller cells was examined by RT-PCR, ELISA, and Western blot. The effect of recombinant VEGF-B or VEGF-B neutralization on Müller cell viability and survival under normal, hypoxic, and oxidative (4-hydroxynonenal [4-HNE]) conditions was evaluated by Alamar Blue, Yo-Pro uptake, and immunocytochemistry. The expression of glial fibrillary acidic protein, aquaporin-4, inward rectifying K+ channel subtype 4.1, glutamine synthetase, and transient receptor potential vanilloid 4 under different treatment conditions was examined by RT-PCR, immunocytochemistry, and Western blot. Transient receptor potential vanilloid 4 channel activity was assessed using a Fura-2–based calcium assay. Results VEGF-B was expressed in Müller cells at the highest levels compared with other members of the VEGF family. VEGF-B neutralization did not affect Müller cell viability or functionality under normal conditions, but enhanced hypoxia– or 4-HNE–induced Müller cell death and decreased inward rectifying K+ channel subtype 4.1 and aquaporin-4 expression. Recombinant VEGF-B restored Müller cell glutamine synthetase expression under hypoxic conditions and protected Müller cells from 4-HNE–induced damage by normalizing transient receptor potential vanilloid 4 channel expression and activity. Conclusions Autocrine production of VEGF-B protects Müller cells under pathologic conditions.
Collapse
Affiliation(s)
- María Llorián-Salvador
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL. Belfast, United Kingdom
| | - Peter Barabas
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL. Belfast, United Kingdom
| | - Eimear M Byrne
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL. Belfast, United Kingdom
| | - Judith Lechner
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL. Belfast, United Kingdom
| | - Josy Augustine
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL. Belfast, United Kingdom
| | - Timothy M Curtis
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL. Belfast, United Kingdom
| | - Mei Chen
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL. Belfast, United Kingdom
| | - Heping Xu
- Wellcome-Wolfson Institute for Experimental Medicine, School of Medicine, Dentistry and Biomedical Sciences, Queen's University Belfast, BT9 7BL. Belfast, United Kingdom
| |
Collapse
|
38
|
Neuropathy-causing TRPV4 mutations disrupt TRPV4-RhoA interactions and impair neurite extension. Nat Commun 2021; 12:1444. [PMID: 33664271 PMCID: PMC7933254 DOI: 10.1038/s41467-021-21699-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Accepted: 02/02/2021] [Indexed: 12/19/2022] Open
Abstract
TRPV4 is a cell surface-expressed calcium-permeable cation channel that mediates cell-specific effects on cellular morphology and function. Dominant missense mutations of TRPV4 cause distinct, tissue-specific diseases, but the pathogenic mechanisms are unknown. Mutations causing peripheral neuropathy localize to the intracellular N-terminal domain whereas skeletal dysplasia mutations are in multiple domains. Using an unbiased screen, we identified the cytoskeletal remodeling GTPase RhoA as a TRPV4 interactor. TRPV4-RhoA binding occurs via the TRPV4 N-terminal domain, resulting in suppression of TRPV4 channel activity, inhibition of RhoA activation, and extension of neurites in vitro. Neuropathy but not skeletal dysplasia mutations disrupt TRPV4-RhoA binding and cytoskeletal outgrowth. However, inhibition of RhoA restores neurite length in vitro and in a fly model of TRPV4 neuropathy. Together these results identify RhoA as a critical mediator of TRPV4-induced cell structure changes and suggest that disruption of TRPV4-RhoA binding may contribute to tissue-specific toxicity of TRPV4 neuropathy mutations. TRPV4 dominant mutations cause neuropathy. Here, the authors show that TRPV4 binds and interacts with RhoA, modulating the actin cytoskeleton. Neuropathy-causing mutations of TRPV4 disrupt this complex, leading to RhoA activation and impairment of neurite extension in cultured cells and flies.
Collapse
|
39
|
Redmon SN, Yarishkin O, Lakk M, Jo A, Mustafić E, Tvrdik P, Križaj D. TRPV4 channels mediate the mechanoresponse in retinal microglia. Glia 2021; 69:1563-1582. [PMID: 33624376 PMCID: PMC8989051 DOI: 10.1002/glia.23979] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 02/02/2021] [Accepted: 02/02/2021] [Indexed: 12/12/2022]
Abstract
The physiological and neurological correlates of plummeting brain osmolality during edema, traumatic CNS injury, and severe ischemia are compounded by neuroinflammation. Using multiple approaches, we investigated how retinal microglia respond to challenges mediated by increases in strain, osmotic gradients, and agonists of the stretch-activated cation channel TRPV4. Dissociated and intact microglia were TRPV4-immunoreactive and responded to the selective agonist GSK1016790A and substrate stretch with altered motility and elevations in intracellular calcium ([Ca2+ ]i ). Agonist- and hypotonicity-induced swelling was associated with a nonselective outwardly rectifying cation current, increased [Ca2+ ]i , and retraction of higher-order processes. The antagonist HC067047 reduced the extent of hypotonicity-induced microglial swelling and inhibited the suppressive effects of GSK1016790A and hypotonicity on microglial branching. Microglial TRPV4 signaling required intermediary activation of phospholipase A2 (PLA2), cytochrome P450, and epoxyeicosatrienoic acid production (EETs). The expression pattern of vanilloid thermoTrp genes in retinal microglia was markedly different from retinal neurons, astrocytes, and cortical microglia. These results suggest that TRPV4 represents a primary retinal microglial sensor of osmochallenges under physiological and pathological conditions. Its activation, associated with PLA2, modulates calcium signaling and cell architecture. TRPV4 inhibition might be a useful strategy to suppress microglial overactivation in the swollen and edematous CNS.
Collapse
Affiliation(s)
- Sarah N Redmon
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Oleg Yarishkin
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Monika Lakk
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Andrew Jo
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Edin Mustafić
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA
| | - Petr Tvrdik
- Department of Neurological Surgery, University of Virginia School of Medicine, Charlottesville, Virginia, USA
| | - David Križaj
- Department of Ophthalmology & Visual Sciences, Moran Eye Institute, Salt Lake City, Utah, USA.,Interdepartmental Program in Neuroscience, 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
| |
Collapse
|
40
|
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.
Collapse
|
41
|
Beddek K, Raffin F, Borgel D, Saller F, Riccobono D, Bobe R, Boittin F. TRPV4 channel activation induces the transition of venous and arterial endothelial cells toward a pro-inflammatory phenotype. Physiol Rep 2021; 9:e14613. [PMID: 33512067 PMCID: PMC7845413 DOI: 10.14814/phy2.14613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2020] [Revised: 09/20/2020] [Accepted: 09/22/2020] [Indexed: 11/24/2022] Open
Abstract
The Transient Receptor Potential Vanilloid 4 (TRPV4) of endothelial cells contributes to many important functions including the regulation of Ca2+ homeostasis, cell volume, endothelial barrier permeability, and smooth muscle tone. However, its role in the transition of endothelial cells toward a pro-inflammatory phenotype has not been studied so far. Using both arterial and venous endothelial cells, we first show that the pharmacological activation of TRPV4 channels with GSK1016790A, a potent TRPV4 agonist, triggers robust and sustained Ca2+ increases, which are blocked by both TRPV4 antagonists HC067047 and RN9893. TRPV4 activation also triggers the actin cytoskeleton and adherens junction (VE-Cadherin) rearrangement in both arterial and venous endothelial cells and leads to rapid decreases of trans-endothelial electrical resistance. In addition to its effect on endothelial barrier integrity, TRPV4 activation selectively increases ICAM-1 surface expression in arterial and venous endothelial cells, due to the stimulation of ICAM-1 gene expression through the NF-κB transcription factor. TRPV4 channel activation also induced apoptosis of venous and arterial endothelial cells, while TRPV4 blockade reduced apoptosis, even in the absence of TRPV4 activation. As altered barrier integrity, increased adhesion molecule expression and apoptosis are hallmarks of the pro-inflammatory state of endothelial cells, our results indicate that TRPV4 channel activity can induce the transition of both venous and arterial endothelial cells toward a pro-inflammatory phenotype.
Collapse
Affiliation(s)
- Kathia Beddek
- INSERM Unité Mixte de Recherche‐Santé 1176Université Paris‐SudUniversité Paris‐SaclayLe Kremlin‐BicêtreFrance
| | - Florent Raffin
- Département des Plateformesunité Analyses BiologiquesIRBA (Institut de Recherche Biomédicale des Armées)Brétigny‐sur‐OrgeFrance
| | - Delphine Borgel
- INSERM Unité Mixte de Recherche‐Santé 1176Université Paris‐SudUniversité Paris‐SaclayLe Kremlin‐BicêtreFrance
| | - François Saller
- INSERM Unité Mixte de Recherche‐Santé 1176Université Paris‐SudUniversité Paris‐SaclayLe Kremlin‐BicêtreFrance
| | - Diane Riccobono
- Département Effets Biologiques des Rayonnementsunité de RadiobiologieIRBA (Institut de Recherche Biomédicale des Armées)Brétigny‐sur‐OrgeFrance
| | - Régis Bobe
- INSERM Unité Mixte de Recherche‐Santé 1176Université Paris‐SudUniversité Paris‐SaclayLe Kremlin‐BicêtreFrance
| | - François‐Xavier Boittin
- Département Effets Biologiques des Rayonnementsunité de RadiobiologieIRBA (Institut de Recherche Biomédicale des Armées)Brétigny‐sur‐OrgeFrance
| |
Collapse
|
42
|
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
Collapse
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
| |
Collapse
|
43
|
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.
Collapse
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
| |
Collapse
|
44
|
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.
Collapse
Affiliation(s)
- Ji-Jie Pang
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX, USA
| |
Collapse
|
45
|
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.
Collapse
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
| |
Collapse
|
46
|
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
| |
Collapse
|
47
|
Swain SM, Liddle RA. Piezo1 acts upstream of TRPV4 to induce pathological changes in endothelial cells due to shear stress. J Biol Chem 2020; 296:100171. [PMID: 33298523 PMCID: PMC7948745 DOI: 10.1074/jbc.ra120.015059] [Citation(s) in RCA: 76] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 12/07/2020] [Accepted: 12/09/2020] [Indexed: 12/24/2022] Open
Abstract
The ion channels Piezo1 and TRPV4 have both, independently, been implicated in high venous pressure- and fluid shear stress-induced vascular hyperpermeability in endothelial cells. However, the mechanism by which Piezo1 and TRPV4 channels execute the same function is poorly understood. Here we demonstrate that Piezo1 regulates TRPV4 channel activation in endothelial cells and that Piezo1-mediated TRPV4 channel opening is a function of the strength and duration of fluid shear stress. We first confirmed that either fluid shear stress or the Piezo1 agonist, Yoda1, led to an elevation in intracellular calcium ([Ca2+]i) and that application of the Piezo1 antagonist, GsMTx4, completely blocked this change. We discovered that high and prolonged shear stress caused sustained [Ca2+]i elevation that was blocked by inhibition of TRPV4 channel opening. Moreover, Piezo1 stimulated TRPV4 opening through activation of phospholipase A2. TRPV4-dependent sustained [Ca2+]i elevation was responsible for fluid shear stress-mediated and Piezo1-mediated disruption of adherens junctions and actin remodeling. Blockade of TRPV4 channels with the selective TRPV4 blocker, HC067047, prevented the loss of endothelial cell integrity and actin disruption induced by Yoda1 or shear stress and prevented Piezo1-induced monocyte adhesion to endothelial cell monolayers. These findings demonstrate that Piezo1 activation by fluid shear stress initiates a calcium signal that causes TRPV4 opening, which in turn is responsible for the sustained phase calcium elevation that triggers pathological events in endothelial cells. Thus, deleterious effects of shear stress are initiated by Piezo1 but require TRPV4.
Collapse
Affiliation(s)
- Sandip M Swain
- Department of Medicine, Duke University, Durham, North Carolina, USA
| | - Rodger A Liddle
- Department of Medicine, Duke University, Durham, North Carolina, USA; Department of Veterans Affairs Health Care System, Durham, North Carolina, USA.
| |
Collapse
|
48
|
Li X, Cheng Y, Wang Z, Zhou J, Jia Y, He X, Zhao L, Dong Y, Fan Y, Yang X, Shen B, Wu X, Wang J, Xiong C, Wei L, Li X, Wang J. Calcium and TRPV4 promote metastasis by regulating cytoskeleton through the RhoA/ROCK1 pathway in endometrial cancer. Cell Death Dis 2020; 11:1009. [PMID: 33230171 PMCID: PMC7683721 DOI: 10.1038/s41419-020-03181-7] [Citation(s) in RCA: 52] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2020] [Revised: 10/27/2020] [Accepted: 10/27/2020] [Indexed: 12/11/2022]
Abstract
Transient receptor potential vanilloid 4 (TRPV4) is a calcium-permeable cation channel that has been associated with several types of cancer. However, its biological significance, as well as its related mechanism in endometrial cancer (EC) still remains elusive. In this study, we examined the function of calcium in EC, with a specific focus on TRPV4 and its downstream pathway. We reported here on the findings that a high level of serum ionized calcium was significantly correlated with advanced EC progression, and among all the calcium channels, TRPV4 played an essential role, with high levels of TRPV4 expression associated with cancer progression both in vitro and in vivo. Proteomic and bioinformatics analysis revealed that TRPV4 was involved in cytoskeleton regulation and Rho protein pathway, which regulated EC cell migration. Mechanistic investigation demonstrated that TRPV4 and calcium influx acted on the cytoskeleton via the RhoA/ROCK1 pathway, ending with LIMK/cofilin activation, which had an impact on F-actin and paxillin (PXN) levels. Overall, our findings indicated that ionized serum calcium level was significantly associated with poor outcomes and calcium channel TRPV4 should be targeted to improve therapeutic and preventive strategies in EC.
Collapse
Affiliation(s)
- Xingchen Li
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China
| | - Yuan Cheng
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China
| | - Zhiqi Wang
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China
| | - Jingyi Zhou
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China.,Beijing Key Laboratory of Female Pelvic Floor Disorders Diseases, Beijing, 100044, China
| | - Yuanyuan Jia
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China.,Beijing Key Laboratory of Female Pelvic Floor Disorders Diseases, Beijing, 100044, China
| | - Xiangjun He
- Department of Central Laboratory & Institute of Clinical Molecular Biology, Peking University People's Hospital, Beijing, 100044, China
| | - Lijun Zhao
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China.,Beijing Key Laboratory of Female Pelvic Floor Disorders Diseases, Beijing, 100044, China
| | - Yangyang Dong
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China
| | - Yuan Fan
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China
| | - Xiao Yang
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China
| | - Boqiang Shen
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China
| | - Xiaotong Wu
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China.,Beijing Key Laboratory of Female Pelvic Floor Disorders Diseases, Beijing, 100044, China
| | - Jiaqi Wang
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China.,Beijing Key Laboratory of Female Pelvic Floor Disorders Diseases, Beijing, 100044, China
| | - Chunyang Xiong
- Department of Mechanics and Bioengineering, College of Engineering, Peking University, Beijing, 100871, China
| | - Lihui Wei
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China
| | - Xiaoping Li
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China
| | - Jianliu Wang
- Department of Obstetrics and Gynecology, Peking University People's Hospital, Beijing, 100044, China. .,Beijing Key Laboratory of Female Pelvic Floor Disorders Diseases, Beijing, 100044, China.
| |
Collapse
|
49
|
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.
Collapse
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.
| |
Collapse
|
50
|
Li Q, Jin R, Zhang S, Sun X, Wu J. Transient receptor potential vanilloid four channels modulate inhibitory inputs through differential regulation of GABA and glycine receptors in rat retinal ganglion cells. FASEB J 2020; 34:14521-14538. [PMID: 32892440 DOI: 10.1096/fj.201902937rr] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 08/07/2020] [Accepted: 08/18/2020] [Indexed: 01/06/2023]
Abstract
The transient receptor potential vanilloid 4 (TRPV4) channel is widely distributed in the retina. Activation of the TRPV4 channel enhances excitatory signaling from bipolar cells to retinal ganglion cells (RGCs), thereby increasing RGC firing rate and membrane excitability. In this study, we investigated the effect of TRPV4 channel activation on the miniature inhibitory postsynaptic current (mIPSC) in rat RGCs. Our results showed that perfusion with HC-067047, a TRPV4-channel antagonist, significantly reduced the amplitude of RGC mIPSCs. Extracellular application of the TRPV4 channel agonist GSK1016790A (GSK101) enhanced the frequency and amplitude of mIPSCs in ON- and OFF-type RGCs; pre-application of HC-067047 blocked the effect of GSK101 on mIPSCs. Furthermore, TRPV4 channels were able to enhance the frequency and amplitude of glycine receptor (GlyR)-mediated mIPSCs and inhibit the frequency of type A γ-aminobutyric acid receptor (GABAA R)-mediated mIPSCs. Upon intracellular administration or intravitreal injection of GSK101, TRPV4 channel activation reduced the release of presynaptic glycine and enhanced the function and expression of postsynaptic GlyRs; however, it inhibited presynaptic release of GABA, but did not affect postsynaptic GABAA Rs. Our study results provide insight regarding the effect of TRPV4 channel activation on RGCs and offer a potential interventional target for retinal diseases involving TRPV4 channels.
Collapse
Affiliation(s)
- Qian Li
- Eye Institute, Eye and ENT Hospital, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Ruiri Jin
- Department of Gastroenterology, The First Affiliated Hospital of Nanchang University, Nanchang, China
| | - Shenghai Zhang
- Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Xinghuai Sun
- Eye Institute, Eye and ENT Hospital, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| | - Jihong Wu
- Eye Institute, Eye and ENT Hospital, Fudan University, Shanghai, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Shanghai, China.,NHC Key Laboratory of Myopia (Fudan University), Shanghai, China.,Key Laboratory of Myopia, Chinese Academy of Medical Sciences, Shanghai, China
| |
Collapse
|