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Redmon SN, Lakk M, Tseng YT, Rudzitis CN, Searle JE, Ahmed F, Unser A, Borrás T, Torrejon K, Krizaj D. TRPV4 subserves physiological and pathological elevations in intraocular pressure. RESEARCH SQUARE 2024:rs.3.rs-4714050. [PMID: 39041037 PMCID: PMC11261973 DOI: 10.21203/rs.3.rs-4714050/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/24/2024]
Abstract
Ocular hypertension (OHT) caused by mechanical stress and chronic glucocorticoid exposure reduces the hydraulic permeability of the conventional outflow pathway. It increases the risk for irreversible vision loss, yet healthy individuals experience nightly intraocular pressure (IOP) elevations without adverse lifetime effects. It is not known which pressure sensors regulate physiological vs. pathological OHT nor how they impact the permeability of the principal drainage pathway through the trabecular meshwork (TM). We report that OHT induced by the circadian rhythm, occlusion of the iridocorneal angle and glucocorticoids requires activation of TRPV4, a stretch-activated cation channel. Wild-type mice responded to nocturnal topical administration of the agonist GSK1016790A with IOP lowering, while intracameral injection of the agonist elevated diurnal IOP. Microinjection of TRPV4 antagonists HC067047 and GSK2193874 lowered IOP during the nocturnal OHT phase and in hypertensive eyes treated with steroids or injection of polystyrene microbeads. Conventional outflow-specific Trpv4 knockdown induced partial IOP lowering in mice with occluded iridocorneal angle and protected retinal neurons from pressure injury. Indicating a central role for TRPV4-dependent mechanosensing in trabecular outflow, HC067047 doubled the outflow facility in TM-populated steroid-treated 3D nanoscaffolds. Tonic TRPV4 signaling thus represents a fundamental property of TM biology as a driver of increased in vitro and in vivo outflow resistance. The TRPV4-dependence of OHT under conditions that mimic primary and secondary glaucomas could be explored as a novel target for glaucoma treatments.
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Sripinun P, See LP, Nikonov S, Chavali VRM, Vrathasha V, He J, O'Brien JM, Xia J, Lu W, Mitchell CH. Piezo1 and Piezo2 channels in retinal ganglion cells and the impact of Piezo1 stimulation on light-dependent neural activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.06.25.599602. [PMID: 38979351 PMCID: PMC11230181 DOI: 10.1101/2024.06.25.599602] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/10/2024]
Abstract
Piezo channels are associated with neuropathology in diseases like traumatic brain injury and glaucoma, but pathways linking tissue stretch to aberrant neural signaling remain unclear. The present study demonstrates that Piezo1 activation increases action potential frequency in response to light and the spontaneous dark signal from mouse retinal explants. Piezo1 stimulation was sufficient to increase cytoplasmic Ca 2+ in soma and neurites, while stretch increased spiking activity in current clamp recordings from of isolated retinal ganglion cells (RGCs). Axon-marker beta-tubulin III colocalized with both Piezo1 and Piezo2 protein in the mouse optic nerve head, while RGC nuclear marker BRN3A colocalized with Piezo channels in the soma. Piezo1 was also present on GFAP-positive regions in the optic nerve head and colocalized with glutamine synthetase in the nerve fiber layer, suggesting expression in optic nerve head astrocytes and Müller glia end feet, respectively. Human RGCs from induced pluripotent stem cells also expressed Piezo1 and Piezo2 in soma and axons, while staining patterns in rats resembled those in mice. mRNA message for Piezo1 was greatest in the RPE/choroid tissue, while Piezo2 levels were highest in the optic nerve, with both channels also expressed in the retina. Increased expression of Piezo1 and Piezo2 occurred both 1 and 10 days after a single stretch in vivo; this increase suggests a potential role in rising sensitivity to repeated nerve stretch. In summary, Piezo1 and Piezo2 were detected in the soma and axons of RGCs, and stimulation affected the light-dependent output of RGCs. The rise in RGCs excitability induced by Piezo stimulation may have parallels to the early disease progression in models of glaucoma and other retinal degenerations. Highlights Activation of Piezo1 excites retinal ganglion cells, paralleling the early neurodegenerative progression in glaucoma mouse models and retinal degeneration.Piezo1 and Piezo2 were expressed in axons and soma of retinal ganglion cells in mice, rats, and human iPSC-RGCs.Functional assays confirmed Piezo1 in soma and neurites of neurons. Sustained elevation of Piezo1 and Piezo2 occurred after a single transient stretch may enhance damage from repeated traumatic nerve injury. Abstract Figure
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Lv L, Zhou LX, Jiang FF. Study on the mechanism of 20-hydroxyeicosatetraenoic acid in retinal ischemia-reperfusion injury. Indian J Ophthalmol 2024; 72:S441-S447. [PMID: 38389249 PMCID: PMC467026 DOI: 10.4103/ijo.ijo_1466_23] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2023] [Revised: 10/24/2023] [Accepted: 11/01/2023] [Indexed: 02/24/2024] Open
Abstract
PURPOSE To explore the effect of 20-hydroxyeicosatetraenoic acid (20-HETE) on retinal ischemia-reperfusion injury (RIRI) and the protective effect of N-hydroxy-N'-(4-n-butyl-2-methylphenyl)formamidine (HET0016) on RIRI. METHODS Male Sprague-Dawley rats were randomly divided into the normal control group, experimental model group (RIRI group), experimental solvent group (RIRI + solvent group), and experimental treatment group (RIRI + HET0016 group). RESULTS The levels of 20-HETE, tumor necrosis factor-α (TNF-α), and interleukin-1β (IL-1β) in the retina of rats at 24 h after reperfusion were measured by enzyme-linked immunosorbent assay. Hematoxylin-eosin staining was used to observe the retinal morphological and thickness changes at 24 h, 48 h, and 7 days after reperfusion. The number and localized expression of matrix metalloproteinase-9-positive cells in the retina of the rats at 24 h after reperfusion and the activation and localized expression of retinal microglia at 48 h after reperfusion were measured using an immunohistochemical method. The nuclear metastasis of nuclear factor kappa-B (NF-κB, p65) cells at 24 h after reperfusion was observed using an immunofluorescence method. CONCLUSION Overall, 20-HETE might activate microglia to aggravate RIRI by the NF-κB pathway, but HET0016 has significant protective effects for the retina.
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Affiliation(s)
- Liang Lv
- Department of Ophthalmology, The Fifth Clinical College of Zhengzhou University, Zhengzhou, China
| | - Li-Xiao Zhou
- Department of Ophthalmology, The Fifth Clinical College of Zhengzhou University, Zhengzhou, China
| | - Fei-Fei Jiang
- Department of Ophthalmology, The Fifth Clinical College of Zhengzhou University, Zhengzhou, China
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Pang JJ. The Variety of Mechanosensitive Ion Channels in Retinal Neurons. Int J Mol Sci 2024; 25:4877. [PMID: 38732096 PMCID: PMC11084373 DOI: 10.3390/ijms25094877] [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: 02/27/2024] [Revised: 04/16/2024] [Accepted: 04/20/2024] [Indexed: 05/13/2024] Open
Abstract
Alterations in intraocular and external pressure critically involve the pathogenesis of glaucoma, traumatic retinal injury (TRI), and other retinal disorders, and retinal neurons have been reported to express multiple mechanical-sensitive channels (MSCs) in recent decades. However, the role of MSCs in visual functions and pressure-related retinal conditions has been unclear. This review will focus on the variety and functional significance of the MSCs permeable to K+, Na+, and Ca2+, primarily including the big potassium channel (BK); the two-pore domain potassium channels TRAAK and TREK; Piezo; the epithelial sodium channel (ENaC); and the transient receptor potential channels vanilloid TRPV1, TRPV2, and TRPV4 in retinal photoreceptors, bipolar cells, horizontal cells, amacrine cells, and ganglion cells. Most MSCs do not directly mediate visual signals in vertebrate retinas. On the other hand, some studies have shown that MSCs can open in physiological conditions and regulate the activities of retinal neurons. While these data reasonably predict the crossing of visual and mechanical signals, how retinal light pathways deal with endogenous and exogenous mechanical stimulation is uncertain.
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Affiliation(s)
- Ji-Jie Pang
- Department of Ophthalmology, Baylor College of Medicine, Houston, TX 77030, USA
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Yaghoobi Z, Seyed Bagher Nazeri SS, Asadi A, Derafsh E, Talebi Taheri A, Tamtaji Z, Dadgostar E, Rahmati-Dehkordi F, Aschner M, Mirzaei H, Tamtaji OR, Nabavizadeh F. Non-coding RNAs and Aquaporin 4: Their Role in the Pathogenesis of Neurological Disorders. Neurochem Res 2024; 49:583-596. [PMID: 38114727 DOI: 10.1007/s11064-023-04067-8] [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: 09/23/2023] [Revised: 11/10/2023] [Accepted: 11/14/2023] [Indexed: 12/21/2023]
Abstract
Neurological disorders are a major group of non-communicable diseases affecting quality of life. Non-Coding RNAs (ncRNAs) have an important role in the etiology of neurological disorders. In studies on the genesis of neurological diseases, aquaporin 4 (AQP4) expression and activity have both been linked to ncRNAs. The upregulation or downregulation of several ncRNAs leads to neurological disorder progression by targeting AQP4. The role of ncRNAs and AQP4 in neurological disorders is discussed in this review.
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Affiliation(s)
- Zahra Yaghoobi
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, I.R. of Iran
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, I.R. of Iran
| | | | - Amir Asadi
- Psychiatry and Behavioral Sciences Research Center, School of Medicine, Addiction Institute, and Department of Psychiatry, Mazandaran University of Medical Sciences, Sari, Iran
| | - Ehsan Derafsh
- Windsor University School of Medicine, Cayon, St Kitts and Nevis
| | - Abdolkarim Talebi Taheri
- Student Research Committee, School of Medicine, Shahid Beheshti University of Medical Sciences, Tehran, Iran
| | - Zeinab Tamtaji
- Student Research Committee, Kashan University of Medical Sciences, Kashan, I.R. of Iran
| | - Ehsan Dadgostar
- Behavioral Sciences Research Center, Isfahan University of Medical Sciences, Isfahan, I.R. of Iran
- Student Research Committee, Isfahan University of Medical Sciences, Isfahan, I.R. of Iran
| | - Fatemeh Rahmati-Dehkordi
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, I.R. of Iran
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, I.R. of Iran
| | - Michael Aschner
- Department of Molecular Pharmacology, Albert Einstein College of Medicine, Bronx, NY, 10461, USA
| | - Hamed Mirzaei
- Research Center for Biochemistry and Nutrition in Metabolic Diseases, Kashan University of Medical Sciences, Kashan, I.R. of Iran.
| | - Omid Reza Tamtaji
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, I.R. of Iran.
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, I.R. of Iran.
| | - Fatemeh Nabavizadeh
- Electrophysiology Research Center, Neuroscience Institute, Tehran University of Medical Sciences, Tehran, I.R. of Iran.
- Department of Physiology, School of Medicine, Tehran University of Medical Sciences, Tehran, I.R. of Iran.
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Izquierdo P, Jolivet RB, Attwell D, Madry C. Amyloid plaques and normal ageing have differential effects on microglial Ca 2+ activity in the mouse brain. Pflugers Arch 2024; 476:257-270. [PMID: 37966547 PMCID: PMC10791787 DOI: 10.1007/s00424-023-02871-3] [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: 08/10/2023] [Revised: 10/02/2023] [Accepted: 10/24/2023] [Indexed: 11/16/2023]
Abstract
In microglia, changes in intracellular calcium concentration ([Ca2+]i) may regulate process motility, inflammasome activation, and phagocytosis. However, while neurons and astrocytes exhibit frequent spontaneous Ca2+ activity, microglial Ca2+ signals are much rarer and poorly understood. Here, we studied [Ca2+]i changes of microglia in acute brain slices using Fluo-4-loaded cells and mice expressing GCaMP5g in microglia. Spontaneous Ca2+ transients occurred ~ 5 times more frequently in individual microglial processes than in their somata. We assessed whether microglial Ca2+ responses change in Alzheimer's disease (AD) using AppNL-G-F knock-in mice. Proximity to Aβ plaques strongly affected microglial Ca2+ activity. Although spontaneous Ca2+ transients were unaffected in microglial processes, they were fivefold more frequent in microglial somata near Aβ plaques than in wild-type microglia. Microglia away from Aβ plaques in AD mice showed intermediate properties for morphology and Ca2+ responses, partly resembling those of wild-type microglia. By contrast, somatic Ca2+ responses evoked by tissue damage were less intense in microglia near Aβ plaques than in wild-type microglia, suggesting different mechanisms underlying spontaneous vs. damage-evoked Ca2+ signals. Finally, as similar processes occur in neurodegeneration and old age, we studied whether ageing affected microglial [Ca2+]i. Somatic damage-evoked Ca2+ responses were greatly reduced in microglia from old mice, as in the AD mice. In contrast to AD, however, old age did not alter the occurrence of spontaneous Ca2+ signals in microglial somata but reduced the rate of events in processes. Thus, we demonstrate distinct compartmentalised Ca2+ activity in microglia from healthy, aged and AD-like brains.
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Affiliation(s)
- Pablo Izquierdo
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK
| | - Renaud B Jolivet
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK
- Maastricht Centre for Systems Biology (MaCSBio), Maastricht University, Paul-Henri Spaaklaan 1, 6229 EN, Maastricht, The Netherlands
| | - David Attwell
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK.
| | - Christian Madry
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, WC1E 6BT, UK.
- Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt Universität Zu Berlin, Institute of Neurophysiology, 10117, Berlin, Germany.
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Tranter JD, Kumar A, Nair VK, Sah R. Mechanosensing in Metabolism. Compr Physiol 2023; 14:5269-5290. [PMID: 38158369 DOI: 10.1002/cphy.c230005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/03/2024]
Abstract
Electrical mechanosensing is a process mediated by specialized ion channels, gated directly or indirectly by mechanical forces, which allows cells to detect and subsequently respond to mechanical stimuli. The activation of mechanosensitive (MS) ion channels, intrinsically gated by mechanical forces, or mechanoresponsive (MR) ion channels, indirectly gated by mechanical forces, results in electrical signaling across lipid bilayers, such as the plasma membrane. While the functions of mechanically gated channels within a sensory context (e.g., proprioception and touch) are well described, there is emerging data demonstrating functions beyond touch and proprioception, including mechanoregulation of intracellular signaling and cellular/systemic metabolism. Both MR and MS ion channel signaling have been shown to contribute to the regulation of metabolic dysfunction, including obesity, insulin resistance, impaired insulin secretion, and inflammation. This review summarizes our current understanding of the contributions of several MS/MR ion channels in cell types implicated in metabolic dysfunction, namely, adipocytes, pancreatic β-cells, hepatocytes, and skeletal muscle cells, and discusses MS/MR ion channels as possible therapeutic targets. © 2024 American Physiological Society. Compr Physiol 14:5269-5290, 2024.
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Affiliation(s)
- John D Tranter
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Ashutosh Kumar
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Vinayak K Nair
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Rajan Sah
- Department of Internal Medicine, Cardiovascular Division, Washington University School of Medicine, St. Louis, Missouri, USA
- Center for Cardiovascular Research, Washington University, St. Louis, Missouri, USA
- St. Louis VA Medical Center, St. Louis, Missouri, USA
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Holloman JP, Dimas SH, Archambault AS, Filipello F, Du L, Feng J, Zhao Y, Bollman B, Piccio L, Steelman AJ, Hu H, Wu GF. Transient Receptor Potential Vanilloid 4-Dependent Microglial Function in Myelin Injury and Repair. Int J Mol Sci 2023; 24:17097. [PMID: 38069420 PMCID: PMC10706888 DOI: 10.3390/ijms242317097] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2023] [Revised: 11/01/2023] [Accepted: 11/21/2023] [Indexed: 12/18/2023] Open
Abstract
Microglia are found pathologically at all stages of multiple sclerosis (MS) lesion development and are hypothesized to contribute to both inflammatory injury and neuroprotection in the MS brain. Transient receptor potential vanilloid 4 (TRPV4) channels are widely expressed, play an important role as environmental sensors, and are involved in calcium homeostasis for a variety of cells. TRPV4 modulates myeloid cell phagocytosis in the periphery and microglial motility in the central nervous system. We hypothesized that TRPV4 deletion would alter microglia phagocytosis in vitro and lessen disease activity and demyelination in experimental autoimmune encephalitis (EAE) and cuprizone-induced demyelination. We found that genetic deletion of TRPV4 led to increased microglial phagocytosis in vitro but did not alter the degree of demyelination or remyelination in the cuprizone mouse model of MS. We also found no difference in disease in EAE following global or microglia-specific deletion of Trpv4. Additionally, lesioned and normal appearing white matter from MS brains exhibited similar TRPV4 expression compared to healthy brain tissue. Taken together, these findings indicate that TRPV4 modulates microglial activity but does not impact disease activity in mouse models of MS, suggesting a muted and/or redundant role in MS pathogenesis.
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Affiliation(s)
- Jameson P. Holloman
- Department of Neurology, Washington University School of Medicine, Saint Louis, MO 63110, USA (F.F.)
| | - Sophia H. Dimas
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; (S.H.D.)
| | - Angela S. Archambault
- Department of Neurology, Washington University School of Medicine, Saint Louis, MO 63110, USA (F.F.)
| | - Fabia Filipello
- Department of Neurology, Washington University School of Medicine, Saint Louis, MO 63110, USA (F.F.)
| | - Lixia Du
- Department of Anesthesiology, The Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO 63110, USA (Y.Z.)
| | - Jing Feng
- Department of Anesthesiology, The Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO 63110, USA (Y.Z.)
| | - Yonghui Zhao
- Department of Anesthesiology, The Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO 63110, USA (Y.Z.)
| | - Bryan Bollman
- Department of Neurology, Washington University School of Medicine, Saint Louis, MO 63110, USA (F.F.)
| | - Laura Piccio
- Department of Neurology, Washington University School of Medicine, Saint Louis, MO 63110, USA (F.F.)
| | - Andrew J. Steelman
- Department of Animal Sciences, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA; (S.H.D.)
- Department Neuroscience Program, Division of Nutritional Sciences, and Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign, Urbana, IL 61801, USA
| | - Hongzhen Hu
- Department of Anesthesiology, The Center for the Study of Itch and Sensory Disorders, Washington University School of Medicine, St. Louis, MO 63110, USA (Y.Z.)
| | - Gregory F. Wu
- Department of Neurology, Washington University School of Medicine, Saint Louis, MO 63110, USA (F.F.)
- Department of Pathology and Immunology, Washington University School of Medicine, Saint Louis, MO 63110, USA
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Wheeler S, Rai-Bhogal R, Crawford DA. Abnormal Microglial Density and Morphology in the Brain of Cyclooxygenase 2 Knockin Mice. Neuroscience 2023; 534:66-81. [PMID: 37863307 DOI: 10.1016/j.neuroscience.2023.10.009] [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: 08/18/2023] [Revised: 10/12/2023] [Accepted: 10/13/2023] [Indexed: 10/22/2023]
Abstract
Prostaglandin E2 (PGE2) is a signaling molecule produced by cyclooxygenase-2 (COX-2) that is important in healthy brain development. Anomalies in the COX-2/PGE2 pathway due to genetic or environmental factors have been linked to Autism Spectrum Disorders (ASD). Our previous studies showed that COX-2 deficient (COX-2-KI) mice exhibit sex-dependent molecular changes in the brain and associated autism-related behaviors. Here, we aim to determine the effect of COX-2-KI on microglial density and morphology in the developing brain. Microglia normally transition between an amoeboid or ramified morphology depending on their surroundings and are important for the development of the healthy brain, assisting with synaptogenesis, synaptic pruning, and phagocytosis. We use COX-2-KI male and female mice to evaluate microglia density, morphology, and branch length and number in five brain regions (cerebellum, hippocampus, olfactory bulb, prefrontal cortex, and thalamus) at the gestational day 19 (G19) and postnatal day 25 (PN25). We discovered that COX2-KI females were affected at G19 with increased microglial density, altered percentage of amoeboid and ramified microglia, affected branch length, and decreased branching networks in a region-specific manner; these effects persisted to PN25 in select regions. Interestingly, while limited changes were found in G19 COX-2-KI males, at PN25 we found increased microglial density, higher percentages of ramified microglia, and increased branch counts, and length observed in nearly all brain regions tested. Overall, we show for the first time that the COX-2 deficiency in our ASD mouse model influences microglia morphology in a sex- and region- and stage-dependent manner.
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Affiliation(s)
- Sarah Wheeler
- School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada; Neuroscience Graduate Diploma Program, York University, Toronto, ON M3J 1P3, Canada
| | | | - Dorota A Crawford
- School of Kinesiology and Health Science, York University, Toronto, ON M3J 1P3, Canada; Neuroscience Graduate Diploma Program, York University, Toronto, ON M3J 1P3, Canada; Department of Biology, York University, Toronto, ON M3J 1P3, Canada.
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10
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Tureckova J, Hermanova Z, Marchetti V, Anderova M. Astrocytic TRPV4 Channels and Their Role in Brain Ischemia. Int J Mol Sci 2023; 24:ijms24087101. [PMID: 37108263 PMCID: PMC10138480 DOI: 10.3390/ijms24087101] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Revised: 04/06/2023] [Accepted: 04/08/2023] [Indexed: 04/29/2023] Open
Abstract
Transient receptor potential cation channels subfamily V member 4 (TRPV4) are non-selective cation channels expressed in different cell types of the central nervous system. These channels can be activated by diverse physical and chemical stimuli, including heat and mechanical stress. In astrocytes, they are involved in the modulation of neuronal excitability, control of blood flow, and brain edema formation. All these processes are significantly impaired in cerebral ischemia due to insufficient blood supply to the tissue, resulting in energy depletion, ionic disbalance, and excitotoxicity. The polymodal cation channel TRPV4, which mediates Ca2+ influx into the cell because of activation by various stimuli, is one of the potential therapeutic targets in the treatment of cerebral ischemia. However, its expression and function vary significantly between brain cell types, and therefore, the effect of its modulation in healthy tissue and pathology needs to be carefully studied and evaluated. In this review, we provide a summary of available information on TRPV4 channels and their expression in healthy and injured neural cells, with a particular focus on their role in ischemic brain injury.
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Affiliation(s)
- Jana Tureckova
- Institute of Experimental Medicine, Czech Academy of Sciences, 1083 Videnska, 142 20 Prague, Czech Republic
| | - Zuzana Hermanova
- Institute of Experimental Medicine, Czech Academy of Sciences, 1083 Videnska, 142 20 Prague, Czech Republic
- Second Faculty of Medicine, Charles University, 84 V Uvalu, 150 06 Prague, Czech Republic
| | - Valeria Marchetti
- Institute of Experimental Medicine, Czech Academy of Sciences, 1083 Videnska, 142 20 Prague, Czech Republic
- Second Faculty of Medicine, Charles University, 84 V Uvalu, 150 06 Prague, Czech Republic
| | - Miroslava Anderova
- Institute of Experimental Medicine, Czech Academy of Sciences, 1083 Videnska, 142 20 Prague, Czech Republic
- Second Faculty of Medicine, Charles University, 84 V Uvalu, 150 06 Prague, Czech Republic
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Dale N, Butler J, Dospinescu VM, Nijjar S. Channel-mediated ATP release in the nervous system. Neuropharmacology 2023; 227:109435. [PMID: 36690324 DOI: 10.1016/j.neuropharm.2023.109435] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/10/2023] [Accepted: 01/19/2023] [Indexed: 01/21/2023]
Abstract
ATP is well established as a transmitter and modulator in the peripheral and central nervous system. While conventional exocytotic release of ATP at synapses occurs, this transmitter is unusual in also being released into the extracellular space via large-pored plasma membrane channels. This review considers the channels that are known to be permeable to ATP and some of the functions of channel-mediated ATP release. While the possibility of ATP release via channels mediating volume transmission has been known for some time, localised ATP release via channels at specialised synapses made by taste cells to the afferent nerve has recently been documented in taste buds. This raises the prospect that "channel synapses" may occur in other contexts. However, volume transmission and channel synapses are not necessarily mutually exclusive. We suggest that certain glial cells in the brain stem and hypothalamus, which possess long processes and are known to release ATP, may be candidates for both modes of ATP release -channel-mediated volume transmission in the region of their somata and more localised transmission possibly via either conventional or channel synapses from their processes at distal targets. Finally, we consider the different characteristics of vesicular and channel synapses and suggest that channel synapses may be advantageous in requiring less energy than their conventional vesicular counterparts. This article is part of the Special Issue on "Purinergic Signaling: 50 years".
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Affiliation(s)
- Nicholas Dale
- School of Life Sciences, University of Warwick, Coventry, CV4, AL, UK.
| | - Jack Butler
- School of Life Sciences, University of Warwick, Coventry, CV4, AL, UK
| | | | - Sarbjit Nijjar
- School of Life Sciences, University of Warwick, Coventry, CV4, AL, UK
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Miao Y, Zhao GL, Cheng S, Wang Z, Yang XL. Activation of retinal glial cells contributes to the degeneration of ganglion cells in experimental glaucoma. Prog Retin Eye Res 2023; 93:101169. [PMID: 36736070 DOI: 10.1016/j.preteyeres.2023.101169] [Citation(s) in RCA: 13] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/02/2022] [Revised: 01/12/2023] [Accepted: 01/24/2023] [Indexed: 02/04/2023]
Abstract
Elevation of intraocular pressure (IOP) is a major risk factor for neurodegeneration in glaucoma. Glial cells, which play an important role in normal functioning of retinal neurons, are well involved into retinal ganglion cell (RGC) degeneration in experimental glaucoma animal models generated by elevated IOP. In response to elevated IOP, mGluR I is first activated and Kir4.1 channels are subsequently inhibited, which leads to the activation of Müller cells. Müller cell activation is followed by a complex process, including proliferation, release of inflammatory and growth factors (gliosis). Gliosis is further regulated by several factors. Activated Müller cells contribute to RGC degeneration through generating glutamate receptor-mediated excitotoxicity, releasing cytotoxic factors and inducing microglia activation. Elevated IOP activates microglia, and following morphological and functional changes, these cells, as resident immune cells in the retina, show adaptive immune responses, including an enhanced release of pro-inflammatory factors (tumor neurosis factor-α, interleukins, etc.). These ATP and Toll-like receptor-mediated responses are further regulated by heat shock proteins, CD200R, chemokine receptors, and metabotropic purinergic receptors, may aggravate RGC loss. In the optic nerve head, astrogliosis is initiated and regulated by a complex reaction process, including purines, transmitters, chemokines, growth factors and cytokines, which contributes to RGC axon injury through releasing pro-inflammatory factors and changing extracellular matrix in glaucoma. The effects of activated glial cells on RGCs are further modified by the interplay among different types of glial cells. This review is concluded by presenting an in-depth discussion of possible research directions in this field in the future.
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Affiliation(s)
- Yanying Miao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Guo-Li Zhao
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Shuo Cheng
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China
| | - Zhongfeng Wang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
| | - Xiong-Li Yang
- State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science, Institutes of Brain Science, Fudan University, Shanghai, 200032, China.
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13
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Hu X, Du L, Liu S, Lan Z, Zang K, Feng J, Zhao Y, Yang X, Xie Z, Wang PL, Ver Heul AM, Chen L, Samineni VK, Wang YQ, Lavine KJ, Gereau RW, Wu GF, Hu H. A TRPV4-dependent neuroimmune axis in the spinal cord promotes neuropathic pain. J Clin Invest 2023; 133:e161507. [PMID: 36701202 PMCID: PMC9974096 DOI: 10.1172/jci161507] [Citation(s) in RCA: 31] [Impact Index Per Article: 31.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Accepted: 01/12/2023] [Indexed: 01/27/2023] Open
Abstract
Microglia, resident macrophages of the CNS, are essential to brain development, homeostasis, and disease. Microglial activation and proliferation are hallmarks of many CNS diseases, including neuropathic pain. However, molecular mechanisms that govern the spinal neuroimmune axis in the setting of neuropathic pain remain incompletely understood. Here, we show that genetic ablation or pharmacological blockade of transient receptor potential vanilloid type 4 (TRPV4) markedly attenuated neuropathic pain-like behaviors in a mouse model of spared nerve injury. Mechanistically, microglia-expressed TRPV4 mediated microglial activation and proliferation and promoted functional and structural plasticity of excitatory spinal neurons through release of lipocalin-2. Our results suggest that microglial TRPV4 channels reside at the center of the neuroimmune axis in the spinal cord, which transforms peripheral nerve injury into central sensitization and neuropathic pain, thereby identifying TRPV4 as a potential new target for the treatment of chronic pain.
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Affiliation(s)
- Xueming Hu
- Department of Anesthesiology, Center for the Study of Itch and Sensory Disorders, and Washington University Pain Center and
| | - Lixia Du
- Department of Anesthesiology, Center for the Study of Itch and Sensory Disorders, and Washington University Pain Center and
| | - Shenbin Liu
- Department of Anesthesiology, Center for the Study of Itch and Sensory Disorders, and Washington University Pain Center and
| | - Zhou Lan
- Department of Anesthesiology, Center for the Study of Itch and Sensory Disorders, and Washington University Pain Center and
| | - Kaikai Zang
- Department of Anesthesiology, Center for the Study of Itch and Sensory Disorders, and Washington University Pain Center and
| | - Jing Feng
- Department of Anesthesiology, Center for the Study of Itch and Sensory Disorders, and Washington University Pain Center and
| | - Yonghui Zhao
- Department of Anesthesiology, Center for the Study of Itch and Sensory Disorders, and Washington University Pain Center and
| | - Xingliang Yang
- Department of Anesthesiology, Center for the Study of Itch and Sensory Disorders, and Washington University Pain Center and
| | - Zili Xie
- Department of Anesthesiology, Center for the Study of Itch and Sensory Disorders, and Washington University Pain Center and
| | - Peter L. Wang
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Aaron M. Ver Heul
- Department of Anesthesiology, Center for the Study of Itch and Sensory Disorders, and Washington University Pain Center and
| | - Lvyi Chen
- Department of Anesthesiology, Center for the Study of Itch and Sensory Disorders, and Washington University Pain Center and
| | - Vijay K. Samineni
- Department of Anesthesiology, Center for the Study of Itch and Sensory Disorders, and Washington University Pain Center and
| | - Yan-Qing Wang
- Institute of Acupuncture and Moxibustion and Institute of Integrative Medicine; Department of Integrative Medicine and Neurobiology, School of Basic Medical Science; and State Key Laboratory of Medical Neurobiology, Institutes of Brain Science, Fudan University, Shanghai, China
| | - Kory J. Lavine
- Department of Internal Medicine, Cardiovascular Division and
| | - Robert W. Gereau
- Department of Anesthesiology, Center for the Study of Itch and Sensory Disorders, and Washington University Pain Center and
| | - Gregory F. Wu
- Department of Pathology and Immunology, Washington University School of Medicine, St. Louis, Missouri, USA
- Department of Neurology, Washington University School of Medicine, St. Louis, Missouri, USA
| | - Hongzhen Hu
- Department of Anesthesiology, Center for the Study of Itch and Sensory Disorders, and Washington University Pain Center and
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14
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Xia CY, Guo YX, Lian WW, Yan Y, Ma BZ, Cheng YC, Xu JK, He J, Zhang WK. The NLRP3 inflammasome in depression: Potential mechanisms and therapies. Pharmacol Res 2023; 187:106625. [PMID: 36563870 DOI: 10.1016/j.phrs.2022.106625] [Citation(s) in RCA: 33] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Revised: 11/20/2022] [Accepted: 12/18/2022] [Indexed: 12/25/2022]
Abstract
Increasing evidence suggests that the failure of clinical antidepressants may be related with neuroinflammation. The NOD-, LRR- and pyrin domain-containing protein 3 (NLRP3) inflammasome is an intracellular multiprotein complex, and has been considered as a key contributor to the development of neuroinflammation. Inhibition of NLRP3 inflammasome is an effective method for depression treatment. In this review, we summarized current researches highlighting the role of NLRP3 inflammasome in the pathology of depression. Firstly, we discussed NLRP3 inflammasome activation in patients with depression and animal models. Secondly, we outlined the possible mechanisms driving the activation of NLRP3 inflammasome. Thirdly, we discussed the pathogenetic role of NLRP3 inflammasome in depression. Finally, we overviewed the current and potential antidepressants targeting the NLRP3 inflammasome. Overall, the inhibition of NLRP3 inflammasome activation may be a potential therapeutic strategy for inflammation-related depression.
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Affiliation(s)
- Cong-Yuan Xia
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China
| | - Yu-Xuan Guo
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing 100029, PR China
| | - Wen-Wen Lian
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China
| | - Yu Yan
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China
| | - Bing-Zhi Ma
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China
| | - Yung-Chi Cheng
- School of Medicine, Yale University, New Haven, CT, United States
| | - Jie-Kun Xu
- School of Life Sciences, Beijing University of Chinese Medicine, Beijing 100029, PR China.
| | - Jun He
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China.
| | - Wei-Ku Zhang
- Department of Pharmacy & Institute of Clinical Medical Sciences, China-Japan Friendship Hospital, Beijing 100029, PR China.
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15
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Križaj D, Cordeiro S, Strauß O. Retinal TRP channels: Cell-type-specific regulators of retinal homeostasis and multimodal integration. Prog Retin Eye Res 2023; 92:101114. [PMID: 36163161 PMCID: PMC9897210 DOI: 10.1016/j.preteyeres.2022.101114] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/16/2022] [Revised: 08/03/2022] [Accepted: 08/08/2022] [Indexed: 02/05/2023]
Abstract
Transient receptor potential (TRP) channels are a widely expressed family of 28 evolutionarily conserved cationic ion channels that operate as primary detectors of chemical and physical stimuli and secondary effectors of metabotropic and ionotropic receptors. In vertebrates, the channels are grouped into six related families: TRPC, TRPV, TRPM, TRPA, TRPML, and TRPP. As sensory transducers, TRP channels are ubiquitously expressed across the body and the CNS, mediating critical functions in mechanosensation, nociception, chemosensing, thermosensing, and phototransduction. This article surveys current knowledge about the expression and function of the TRP family in vertebrate retinas, which, while dedicated to transduction and transmission of visual information, are highly susceptible to non-visual stimuli. Every retinal cell expresses multiple TRP subunits, with recent evidence establishing their critical roles in paradigmatic aspects of vertebrate vision that include TRPM1-dependent transduction of ON bipolar signaling, TRPC6/7-mediated ganglion cell phototransduction, TRP/TRPL phototransduction in Drosophila and TRPV4-dependent osmoregulation, mechanotransduction, and regulation of inner and outer blood-retina barriers. TRP channels tune light-dependent and independent functions of retinal circuits by modulating the intracellular concentration of the 2nd messenger calcium, with emerging evidence implicating specific subunits in the pathogenesis of debilitating diseases such as glaucoma, ocular trauma, diabetic retinopathy, and ischemia. Elucidation of TRP channel involvement in retinal biology will yield rewards in terms of fundamental understanding of vertebrate vision and therapeutic targeting to treat diseases caused by channel dysfunction or over-activation.
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Affiliation(s)
- David Križaj
- Departments of Ophthalmology, Neurobiology, and Bioengineering, University of Utah, Salt Lake City, USA
| | - Soenke Cordeiro
- Institute of Physiology, Faculty of Medicine, Christian-Albrechts-University Kiel, Germany
| | - Olaf Strauß
- Experimental Ophthalmology, Department of Ophthalmology, Charité - Universitätsmedizin Berlin, a Corporate Member of Freie Universität, Humboldt-University, The Berlin Institute of Health, Berlin, Germany.
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16
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Sucha P, Hermanova Z, Chmelova M, Kirdajova D, Camacho Garcia S, Marchetti V, Vorisek I, Tureckova J, Shany E, Jirak D, Anderova M, Vargova L. The absence of AQP4/TRPV4 complex substantially reduces acute cytotoxic edema following ischemic injury. Front Cell Neurosci 2022; 16:1054919. [PMID: 36568889 PMCID: PMC9773096 DOI: 10.3389/fncel.2022.1054919] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2022] [Accepted: 11/22/2022] [Indexed: 12/13/2022] Open
Abstract
Introduction Astrocytic Aquaporin 4 (AQP4) and Transient receptor potential vanilloid 4 (TRPV4) channels form a functional complex that likely influences cell volume regulation, the development of brain edema, and the severity of the ischemic injury. However, it remains to be fully elucidated whether blocking these channels can serve as a therapeutic approach to alleviate the consequences of having a stroke. Methods and results In this study, we used in vivo magnetic resonance imaging (MRI) to quantify the extent of brain lesions one day (D1) and seven days (D7) after permanent middle cerebral artery occlusion (pMCAO) in AQP4 or TRPV4 knockouts and mice with simultaneous deletion of both channels. Our results showed that deletion of AQP4 or TRPV4 channels alone leads to a significant worsening of ischemic brain injury at both time points, whereas their simultaneous deletion results in a smaller brain lesion at D1 but equal tissue damage at D7 when compared with controls. Immunohistochemical analysis 7 days after pMCAO confirmed the MRI data, as the brain lesion was significantly greater in AQP4 or TRPV4 knockouts than in controls and double knockouts. For a closer inspection of the TRPV4 and AQP4 channel complex in the development of brain edema, we applied a real-time iontophoretic method in situ to determine ECS diffusion parameters, namely volume fraction (α) and tortuosity (λ). Changes in these parameters reflect alterations in cell volume, and tissue structure during exposure of acute brain slices to models of ischemic conditions in situ, such as oxygen-glucose deprivation (OGD), hypoosmotic stress, or hyperkalemia. The decrease in α was comparable in double knockouts and controls when exposed to hypoosmotic stress or hyperkalemia. However, during OGD, there was no decrease in α in the double knockouts as observed in the controls, which suggests less swelling of the cellular components of the brain. Conclusion Although simultaneous deletion of AQP4 and TRPV4 did not improve the overall outcome of ischemic brain injury, our data indicate that the interplay between AQP4 and TRPV4 channels plays a critical role during neuronal and non-neuronal swelling in the acute phase of ischemic injury.
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Affiliation(s)
- Petra Sucha
- Second Faculty of Medicine, Charles University, Prague, Czechia,Department of Cellular Neurophysiology, Institute of Experimental Medicine of the CAS, Prague, Czechia
| | - Zuzana Hermanova
- Second Faculty of Medicine, Charles University, Prague, Czechia,Department of Cellular Neurophysiology, Institute of Experimental Medicine of the CAS, Prague, Czechia
| | - Martina Chmelova
- Second Faculty of Medicine, Charles University, Prague, Czechia,Department of Cellular Neurophysiology, Institute of Experimental Medicine of the CAS, Prague, Czechia
| | - Denisa Kirdajova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine of the CAS, Prague, Czechia
| | - Sara Camacho Garcia
- Department of Cellular Neurophysiology, Institute of Experimental Medicine of the CAS, Prague, Czechia
| | - Valeria Marchetti
- Second Faculty of Medicine, Charles University, Prague, Czechia,Department of Cellular Neurophysiology, Institute of Experimental Medicine of the CAS, Prague, Czechia
| | - Ivan Vorisek
- Department of Cellular Neurophysiology, Institute of Experimental Medicine of the CAS, Prague, Czechia
| | - Jana Tureckova
- Department of Cellular Neurophysiology, Institute of Experimental Medicine of the CAS, Prague, Czechia
| | - Eyar Shany
- Department of Diagnostic and Interventional Radiology, Institute of Clinical and Experimental Medicine, Prague, Czechia
| | - Daniel Jirak
- Department of Diagnostic and Interventional Radiology, Institute of Clinical and Experimental Medicine, Prague, Czechia,First Faculty of Medicine, Institute of Biophysics and Informatics, Charles University, Prague, Czechia
| | - Miroslava Anderova
- Second Faculty of Medicine, Charles University, Prague, Czechia,Department of Cellular Neurophysiology, Institute of Experimental Medicine of the CAS, Prague, Czechia,*Correspondence: Miroslava Anderova,
| | - Lydia Vargova
- Second Faculty of Medicine, Charles University, Prague, Czechia,Department of Cellular Neurophysiology, Institute of Experimental Medicine of the CAS, Prague, Czechia
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17
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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: 11] [Impact Index Per Article: 5.5] [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.
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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
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18
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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.
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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.
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19
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Functional microglia derived from human pluripotent stem cells empower retinal organ. SCIENCE CHINA. LIFE SCIENCES 2022; 65:1057-1071. [PMID: 35451725 DOI: 10.1007/s11427-021-2086-0] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Revised: 03/07/2022] [Accepted: 03/07/2022] [Indexed: 12/13/2022]
Abstract
Microglia are known to play essential roles in the development, progression and treatment of diverse neurodegenerative diseases in the central nervous system, including the retina, brain and spinal cord. Recently, brain-induced microglia-like cells (iMGs) have been generated from human pluripotent stem cells (hPSCs); however, retinal microglia have yet to be developed in vitro. In this study, by mimicking in vivo microglial development, we established a simplified approach to differentiate hPSCs into high purity (>90%) iMGs. The iMGs express microglia-specific markers, release cytokines upon stimulation, and are capable of phagocytizing bacteria. When co-cultured with three-dimensional human retinal organoids (hROs), iMGs migrated into the hROs, tended to differentiate into resident retinal microglia, and simultaneously induced apoptosis in some neural cells. Notably, the resident iMGs in the hROs formed sparse web-like structures beneath the photoreceptor cell layer, resembling microglia's orientation in human retina. In conclusion, we developed a simplified and efficient method to generate microglia from human pluripotent stem cells, and we report the first derivation of retinaresident microglia in vitro, providing a new source of human retinal microglia for developmental and disease studies and regenerative therapeutics.
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20
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Yarishkin O, Phuong TTT, Vazquez-Chona F, Bertrand J, van Battenburg-Sherwood J, Redmon SN, Rudzitis CN, Lakk M, Baumann JM, Freichel M, Hwang EM, Overby D, Križaj D. Emergent Temporal Signaling in Human Trabecular Meshwork Cells: Role of TRPV4-TRPM4 Interactions. Front Immunol 2022; 13:805076. [PMID: 35432302 PMCID: PMC9008486 DOI: 10.3389/fimmu.2022.805076] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/29/2021] [Accepted: 03/02/2022] [Indexed: 11/26/2022] Open
Abstract
Trabecular meshwork (TM) cells are phagocytic cells that employ mechanotransduction to actively regulate intraocular pressure. Similar to macrophages, they express scavenger receptors and participate in antigen presentation within the immunosuppressive milieu of the anterior eye. Changes in pressure deform and compress the TM, altering their control of aqueous humor outflow but it is not known whether transducer activation shapes temporal signaling. The present study combines electrophysiology, histochemistry and functional imaging with gene silencing and heterologous expression to gain insight into Ca2+ signaling downstream from TRPV4 (Transient Receptor Potential Vanilloid 4), a stretch-activated polymodal cation channel. Human TM cells respond to the TRPV4 agonist GSK1016790A with fluctuations in intracellular Ca2+ concentration ([Ca2+]i) and an increase in [Na+]i. [Ca2+]i oscillations coincided with monovalent cation current that was suppressed by BAPTA, Ruthenium Red and the TRPM4 (Transient Receptor Potential Melastatin 4) channel inhibitor 9-phenanthrol. TM cells expressed TRPM4 mRNA, protein at the expected 130-150 kDa and showed punctate TRPM4 immunoreactivity at the membrane surface. Genetic silencing of TRPM4 antagonized TRPV4-evoked oscillatory signaling whereas TRPV4 and TRPM4 co-expression in HEK-293 cells reconstituted the oscillations. Membrane potential recordings suggested that TRPM4-dependent oscillations require release of Ca2+ from internal stores. 9-phenanthrol did not affect the outflow facility in mouse eyes and eyes from animals lacking TRPM4 had normal intraocular pressure. Collectively, our results show that TRPV4 activity initiates dynamic calcium signaling in TM cells by stimulating TRPM4 channels and intracellular Ca2+ release. It is possible that TRPV4-TRPM4 interactions downstream from the tensile and compressive impact of intraocular pressure contribute to homeostatic regulation and pathological remodeling within the conventional outflow pathway.
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Affiliation(s)
- Oleg Yarishkin
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States
| | - Tam T T Phuong
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States
| | - Felix Vazquez-Chona
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States
| | - Jacques Bertrand
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | | | - Sarah N Redmon
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States
| | - Christopher N Rudzitis
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States.,Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, United States
| | - Monika Lakk
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States
| | - Jackson M Baumann
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States.,Department of Bioengineering, University of Utah, Salt Lake City, United States
| | - Marc Freichel
- Institute of Pharmacology, Heidelberg University, Heidelberg, Germany
| | - Eun-Mi Hwang
- Center for Functional Connectomics, Korea Institute of Science and Technology (KIST), Seoul, South Korea
| | - Darryl Overby
- Department of Bioengineering, Imperial College London, London, United Kingdom
| | - David Križaj
- Department of Ophthalmology and Visual Sciences, University of Utah School of Medicine, Salt Lake City, United States.,Interdepartmental Program in Neuroscience, University of Utah, Salt Lake City, United States.,Department of Bioengineering, University of Utah, Salt Lake City, United States.,Department of Neurobiology, University of Utah, Salt Lake City, United States
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21
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Chakraborty R, Goswami C. Both heat-sensitive TRPV4 and cold-sensitive TRPM8 ion channels regulate microglial activity. Biochem Biophys Res Commun 2022; 611:132-139. [PMID: 35489198 DOI: 10.1016/j.bbrc.2022.04.032] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Accepted: 04/07/2022] [Indexed: 11/02/2022]
Abstract
Microglia, the brain-resident macrophages, perform a myriad of functions directed towards development of neural circuits, and their maintenance. A plethora of ion channels aid in microglial activities that are critical for overall brain functioning. Notably, different functions of microglial cells are sensitive to minute temperature changes, as well as mechanical forces. Therefore, among all the players involved in the regulation of microglial functions, thermosensitive TRP ion channels are potentially important. In this study, we report the endogenous and functional presence of a heat-sensitive ion channel TRPV4 and a cold-sensitive ion channel TRPM8 in primary rat microglia and microglial cell line, N9. We demonstrate that pharmacological modulations of both these channels affect intracellular Ca2+-levels, cellular morphology, migration, and motility. Thus, TRPV4 and TRPM8 act as potential regulators of microglial activities. These findings may have broad implications in understanding neuro-glia interactions in neurodevelopmental and neurodegenerative pathologies with overall bio-medical applications.
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Affiliation(s)
- Ranabir Chakraborty
- School of Biological Sciences, National Institute of Science Education and Research, Khurda, Odisha, 752050, India
| | - Chandan Goswami
- School of Biological Sciences, National Institute of Science Education and Research, Khurda, Odisha, 752050, India; Homi Bhabha National Institute, Mumbai, 400094, India.
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22
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Liu N, Bai L, Lu Z, Gu R, Zhao D, Yan F, Bai J. TRPV4 contributes to ER stress and inflammation: implications for Parkinson’s disease. J Neuroinflammation 2022; 19:26. [PMID: 35093118 PMCID: PMC8800324 DOI: 10.1186/s12974-022-02382-5] [Citation(s) in RCA: 25] [Impact Index Per Article: 12.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Accepted: 01/10/2022] [Indexed: 12/13/2022] Open
Abstract
Background Parkinson’s disease (PD) is a progressive neurodegenerative disorder. Its molecular mechanism is still unclear, and pharmacological treatments are unsatisfactory. Transient receptor potential vanilloid 4 (TRPV4) is a nonselective Ca2+ channel. It has recently emerged as a critical risk factor in the pathophysiology of neuronal injuries and cerebral diseases. Our previous study reported that TRPV4 contributed to endoplasmic reticulum (ER) stress in the MPP+-induced cell model of PD. In the present study, we detected the role and the mechanism of TRPV4 in 1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced PD mice. Methods Intracerebral injection of an adeno-associated virus (AAV) into the substantia nigra (SN) of mice was used to knockdown or upregulate the expression of TRPV4 and intraperitoneal injection of MPTP. Rotarod and pole tests were used to evaluate the locomotor ability of mice. We used immunohistochemistry, Nissl staining and Western blot to detect the alterations in the number of tyrosine hydroxylase (TH)-positive neurons, Nissl-positive neurons, the levels of ER stress-associated molecules and proinflammatory cytokines in the SN. Results The SN was transfected with AAV for 3 weeks and expressed the target protein with green fluorescence. Knockdown of TRPV4 via injection of a constructed AAV-TRPV4 shRNAi into the SN alleviated the movement deficits of PD mice. Upregulation of TRPV4 via injection of a constructed AAV-TRPV4 aggravated the above movement disorders. The expression of TRPV4 was upregulated in the SN of MPTP-treated mice. Injection of AAV-TRPV4 shRNAi into the SN rescued the number of TH-positive and Nissl-positive neurons in the SN decreased by MPTP, while injection of AAV-TRPV4 induced the opposite effect. Moreover, MPTP-decreased Sarco/endoplasmic reticulum Ca2+-ATPase 2 (SERCA2) and pro-cysteinyl aspartate specific proteinase-12 (procaspase-12), MPTP-increased Glucose-regulated protein 78 (GRP78), Glucose-regulated protein 94 (GRP94) and C/EBP homologous protein (CHOP) were inhibited by AAV-TRPV4 shRNAi infection, and enhanced by AAV-TRPV4. In the same way, MPTP-decreased procaspase-1, MPTP-increased Interleukin-18 (IL-18), Cyclooxgenase-2 (COX-2) and 5-Lipoxygenase (5-LOX) were inhibited by AAV-TRPV4 shRNAi, or further exacerbated by AAV-TRPV4. Conclusions These results suggest that TRPV4 mediates ER stress and inflammation pathways, contributing to the loss of dopamine (DA) neurons in the SN and movement deficits in PD mice. Moreover, this study provides a new perspective on molecular targets and gene therapies for the treatment of PD in the future.
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23
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Nisembaum LG, Loentgen G, L’Honoré T, Martin P, Paulin CH, Fuentès M, Escoubeyrou K, Delgado MJ, Besseau L, Falcón J. Transient Receptor Potential-Vanilloid (TRPV1-TRPV4) Channels in the Atlantic Salmon, Salmo salar. A Focus on the Pineal Gland and Melatonin Production. Front Physiol 2022; 12:784416. [PMID: 35069244 PMCID: PMC8782258 DOI: 10.3389/fphys.2021.784416] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2021] [Accepted: 12/07/2021] [Indexed: 11/13/2022] Open
Abstract
Fish are ectotherm, which rely on the external temperature to regulate their internal body temperature, although some may perform partial endothermy. Together with photoperiod, temperature oscillations, contribute to synchronizing the daily and seasonal variations of fish metabolism, physiology and behavior. Recent studies are shedding light on the mechanisms of temperature sensing and behavioral thermoregulation in fish. In particular, the role of some members of the transient receptor potential channels (TRP) is being gradually unraveled. The present study in the migratory Atlantic salmon, Salmo salar, aims at identifying the tissue distribution and abundance in mRNA corresponding to the TRP of the vanilloid subfamilies, TRPV1 and TRPV4, and at characterizing their putative role in the control of the temperature-dependent modulation of melatonin production-the time-keeping hormone-by the pineal gland. In Salmo salar, TRPV1 and TRPV4 mRNA tissue distribution appeared ubiquitous; mRNA abundance varied as a function of the month investigated. In situ hybridization and immunohistochemistry indicated specific labeling located in the photoreceptor cells of the pineal gland and the retina. Additionally, TRPV analogs modulated the production of melatonin by isolated pineal glands in culture. The TRPV1 agonist induced an inhibitory response at high concentrations, while evoking a bell-shaped response (stimulatory at low, and inhibitory at high, concentrations) when added with an antagonist. The TRPV4 agonist was stimulatory at the highest concentration used. Altogether, the present results agree with the known widespread distribution and role of TRPV1 and TRPV4 channels, and with published data on trout (Oncorhynchus mykiss), leading to suggest these channels mediate the effects of temperature on S. salar pineal melatonin production. We discuss their involvement in controlling the timing of daily and seasonal events in this migratory species, in the context of an increasing warming of water temperatures.
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Affiliation(s)
- Laura Gabriela Nisembaum
- Sorbonne Université (SU), CNRS, Biologie Intégrative des Organismes Marins (BIOM), Banyuls-sur-Mer, France
| | - Guillaume Loentgen
- Sorbonne Université (SU), CNRS, Biologie Intégrative des Organismes Marins (BIOM), Banyuls-sur-Mer, France
| | - Thibaut L’Honoré
- Sorbonne Université (SU), CNRS, Biologie Intégrative des Organismes Marins (BIOM), Banyuls-sur-Mer, France
| | - Patrick Martin
- Conservatoire National du Saumon Sauvage, Chanteuges, France
| | - Charles-Hubert Paulin
- Sorbonne Université (SU), CNRS, Biologie Intégrative des Organismes Marins (BIOM), Banyuls-sur-Mer, France
| | - Michael Fuentès
- Sorbonne Université (SU), CNRS, Biologie Intégrative des Organismes Marins (BIOM), Banyuls-sur-Mer, France
| | - Karine Escoubeyrou
- SU, CNRS Fédération 3724, Observatoire Océanologique, Banyuls-sur-Mer, France
| | - María Jesús Delgado
- Departamento de Genética, Fisiología y Microbiologia, Facultad de Biología, Universidad Complutense de Madrid, Madrid, Spain
| | - Laurence Besseau
- Sorbonne Université (SU), CNRS, Biologie Intégrative des Organismes Marins (BIOM), Banyuls-sur-Mer, France
| | - Jack Falcón
- Sorbonne Université (SU), CNRS, Biologie Intégrative des Organismes Marins (BIOM), Banyuls-sur-Mer, France
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Lapajne L, Rudzitis CN, Cullimore B, Ryskamp D, Lakk M, Redmon S, Yarishkin O, Križaj D. TRPV4: Cell type-specific activation, regulation and function in the vertebrate eye. CURRENT TOPICS IN MEMBRANES 2022; 89:189-219. [PMID: 36210149 PMCID: PMC9879314 DOI: 10.1016/bs.ctm.2022.07.005] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
The architecture of the vertebrate eye is optimized for efficient delivery and transduction of photons and processing of signaling cascades downstream from phototransduction. The cornea, lens, retina, vasculature, ciliary body, ciliary muscle, iris and sclera have specialized functions in ocular protection, transparency, accommodation, fluid regulation, metabolism and inflammatory signaling, which are required to enable function of the retina-light sensitive tissue in the posterior eye that transmits visual signals to relay centers in the midbrain. This process can be profoundly impacted by non-visual stimuli such as mechanical (tension, compression, shear), thermal, nociceptive, immune and chemical stimuli, which target these eye regions to induce pain and precipitate vision loss in glaucoma, diabetic retinopathy, retinal dystrophies, retinal detachment, cataract, corneal dysfunction, ocular trauma and dry eye disease. TRPV4, a polymodal nonselective cation channel, integrate non-visual inputs with homeostatic and signaling functions of the eye. The TRPV4 gene is expressed in most if not all ocular tissues, which vary widely with respect to the mechanisms of TRPV4 channel activation, modulation, oligomerization, and participation in protein- and lipid interactions. Under- and overactivation of TRPV4 may affect intraocular pressure, maintenance of blood-retina barriers, lens accommodation, neuronal function and neuroinflammation. Because TRPV4 dysregulation precipitates many pathologies across the anterior and posterior eye, the channel could be targeted to mitigate vision loss.
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Affiliation(s)
- Luka Lapajne
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132,Department of Ophthalmology, University Medical Centre, University of Ljubljana, Slovenia
| | - Christopher N. Rudzitis
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Brenan Cullimore
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Daniel Ryskamp
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Monika Lakk
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Sarah Redmon
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - Oleg Yarishkin
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132
| | - David Križaj
- Department of Ophthalmology & Visual Sciences, University of Utah School of Medicine, Salt Lake City, UT 84132,Department of Neurobiology, University of Utah, Salt Lake City, UT 84112,Department of Bioengineering, University of Utah, Salt Lake City, UT 84112
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25
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Mechanosensing and the Hippo Pathway in Microglia: A Potential Link to Alzheimer's Disease Pathogenesis? Cells 2021; 10:cells10113144. [PMID: 34831369 PMCID: PMC8622675 DOI: 10.3390/cells10113144] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Revised: 10/27/2021] [Accepted: 10/29/2021] [Indexed: 01/01/2023] Open
Abstract
The activation of microglia, the inflammatory cells of the central nervous system (CNS), has been linked to the pathogenesis of Alzheimer’s disease and other neurodegenerative diseases. How microglia sense the changing brain environment, in order to respond appropriately, is still being elucidated. Microglia are able to sense and respond to the mechanical properties of their microenvironment, and the physical and molecular pathways underlying this mechanosensing/mechanotransduction in microglia have recently been investigated. The Hippo pathway functions through mechanosensing and subsequent protein kinase cascades, and is critical for neuronal development and many other cellular processes. In this review, we examine evidence for the potential involvement of Hippo pathway components specifically in microglia in the pathogenesis of Alzheimer’s disease. We suggest that the Hippo pathway is worth investigating as a mechanosensing pathway in microglia, and could be one potential therapeutic target pathway for preventing microglial-induced neurodegeneration in AD.
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26
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Nosi D, Lana D, Giovannini MG, Delfino G, Zecchi-Orlandini S. Neuroinflammation: Integrated Nervous Tissue Response through Intercellular Interactions at the "Whole System" Scale. Cells 2021; 10:cells10051195. [PMID: 34068375 PMCID: PMC8153304 DOI: 10.3390/cells10051195] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2021] [Revised: 05/07/2021] [Accepted: 05/10/2021] [Indexed: 12/12/2022] Open
Abstract
Different cell populations in the nervous tissue establish numerous, heterotypic interactions and perform specific, frequently intersecting activities devoted to the maintenance of homeostasis. Microglia and astrocytes, respectively the immune and the “housekeeper” cells of nervous tissue, play a key role in neurodegenerative diseases. Alterations of tissue homeostasis trigger neuroinflammation, a collective dynamic response of glial cells. Reactive astrocytes and microglia express various functional phenotypes, ranging from anti-inflammatory to pro-inflammatory. Chronic neuroinflammation is characterized by a gradual shift of astroglial and microglial phenotypes from anti-inflammatory to pro-inflammatory, switching their activities from cytoprotective to cytotoxic. In this scenario, the different cell populations reciprocally modulate their phenotypes through intense, reverberating signaling. Current evidence suggests that heterotypic interactions are links in an intricate network of mutual influences and interdependencies connecting all cell types in the nervous system. In this view, activation, modulation, as well as outcomes of neuroinflammation, should be ascribed to the nervous tissue as a whole. While the need remains of identifying further links in this network, a step back to rethink our view of neuroinflammation in the light of the “whole system” scale, could help us to understand some of its most controversial and puzzling features.
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Affiliation(s)
- Daniele Nosi
- Section of Histology anf Human Anatomy, Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla, 3, 50134 Florence, Italy;
- Correspondence:
| | - Daniele Lana
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Viale Gaetano Pieraccini, 50139 Florence, Italy; (D.L.); (M.G.G.)
| | - Maria Grazia Giovannini
- Section of Clinical Pharmacology and Oncology, Department of Health Sciences, University of Florence, Viale Gaetano Pieraccini, 50139 Florence, Italy; (D.L.); (M.G.G.)
| | - Giovanni Delfino
- Department of Biology, University of Florence, Via Madonna del Piano, 6, 50019 Sesto Fiorentino, Florence, Italy;
| | - Sandra Zecchi-Orlandini
- Section of Histology anf Human Anatomy, Department of Experimental and Clinical Medicine, University of Florence, Largo Brambilla, 3, 50134 Florence, Italy;
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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: 26] [Impact Index Per Article: 8.7] [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.
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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
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