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Lewis CM, Griffith TN. Ion channels of cold transduction and transmission. J Gen Physiol 2024; 156:e202313529. [PMID: 39051992 DOI: 10.1085/jgp.202313529] [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] [Received: 12/15/2023] [Revised: 06/04/2024] [Accepted: 07/12/2024] [Indexed: 07/27/2024] Open
Abstract
Thermosensation requires the activation of a unique collection of ion channels and receptors that work in concert to transmit thermal information. It is widely accepted that transient receptor potential melastatin 8 (TRPM8) activation is required for normal cold sensing; however, recent studies have illuminated major roles for other ion channels in this important somatic sensation. In addition to TRPM8, other TRP channels have been reported to contribute to cold transduction mechanisms in diverse sensory neuron populations, with both leak- and voltage-gated channels being identified for their role in the transmission of cold signals. Whether the same channels that contribute to physiological cold sensing also mediate noxious cold signaling remains unclear; however, recent work has found a conserved role for the kainite receptor, GluK2, in noxious cold sensing across species. Additionally, cold-sensing neurons likely engage in functional crosstalk with nociceptors to give rise to cold pain. This Review will provide an update on our understanding of the relationship between various ion channels in the transduction and transmission of cold and highlight areas where further investigation is required.
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Affiliation(s)
- Cheyanne M Lewis
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA, USA
| | - Theanne N Griffith
- Department of Physiology and Membrane Biology, University of California Davis, Davis, CA, USA
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2
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Arcas JM, Oudaha K, González A, Fernández-Trillo J, Peralta FA, Castro-Marsal J, Poyraz S, Taberner F, Sala S, de la Peña E, Gomis A, Viana F. The ion channel TRPM8 is a direct target of the immunosuppressant rapamycin in primary sensory neurons. Br J Pharmacol 2024; 181:3192-3214. [PMID: 38741464 DOI: 10.1111/bph.16402] [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: 09/14/2023] [Revised: 02/29/2024] [Accepted: 03/10/2024] [Indexed: 05/16/2024] Open
Abstract
BACKGROUND AND PURPOSE The mechanistic target of rapamycin (mTOR) signalling pathway is a key regulator of cell growth and metabolism. Its deregulation is implicated in several diseases. The macrolide rapamycin, a specific inhibitor of mTOR, has immunosuppressive, anti-inflammatory and antiproliferative properties. Recently, we identified tacrolimus, another macrolide immunosuppressant, as a novel activator of TRPM8 ion channels, involved in cold temperature sensing, thermoregulation, tearing and cold pain. We hypothesized that rapamycin may also have agonist activity on TRPM8 channels. EXPERIMENTAL APPROACH Using calcium imaging and electrophysiology in transfected HEK293 cells and wildtype or Trpm8 KO mouse DRG neurons, we characterized rapamycin's effects on TRPM8 channels. We also examined the effects of rapamycin on tearing in mice. KEY RESULTS Micromolar concentrations of rapamycin activated rat and mouse TRPM8 channels directly and potentiated cold-evoked responses, effects also observed in human TRPM8 channels. In cultured mouse DRG neurons, rapamycin increased intracellular calcium levels almost exclusively in cold-sensitive neurons. Responses were markedly decreased in Trpm8 KO mice or by TRPM8 channel antagonists. Cutaneous cold thermoreceptor endings were also activated by rapamycin. Topical application of rapamycin to the eye surface evokes tearing in mice by a TRPM8-dependent mechanism. CONCLUSION AND IMPLICATIONS These results identify TRPM8 cationic channels in sensory neurons as novel molecular targets of the immunosuppressant rapamycin. These findings may help explain some of its therapeutic effects after topical application to the skin and the eye surface. Moreover, rapamycin could be used as an experimental tool in the clinic to explore cold thermoreceptors.
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Affiliation(s)
- José Miguel Arcas
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Khalid Oudaha
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Alejandro González
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Jorge Fernández-Trillo
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | | | - Júlia Castro-Marsal
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Seyma Poyraz
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Francisco Taberner
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Salvador Sala
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Elvira de la Peña
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Ana Gomis
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Félix Viana
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
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Pizzano M, Vereertbrugghen A, Cernutto A, Sabbione F, Keitelman IA, Shiromizu CM, Vera Aguilar D, Fuentes F, Giordano MN, Trevani AS, Galletti JG. Transient Receptor Potential Vanilloid-1 Channels Facilitate Axonal Degeneration of Corneal Sensory Nerves in Dry Eye. THE AMERICAN JOURNAL OF PATHOLOGY 2024; 194:810-827. [PMID: 38325553 DOI: 10.1016/j.ajpath.2024.01.015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Revised: 12/19/2023] [Accepted: 01/10/2024] [Indexed: 02/09/2024]
Abstract
Corneal nerve impairment contributes significantly to dry eye disease (DED) symptoms and is thought to be secondary to corneal epithelial damage. Transient receptor potential vanilloid-1 (TRPV1) channels abound in corneal nerve fibers and respond to inflammation-derived ligands, which increase in DED. TRPV1 overactivation promotes axonal degeneration in vitro, but whether it participates in DED-associated corneal nerve dysfunction is unknown. To explore this, DED was surgically induced in wild-type and TRPV1-knockout mice, which developed comparable corneal epithelial damage and reduced tear secretion. However, corneal mechanosensitivity decreased progressively only in wild-type DED mice. Sensitivity to capsaicin (TRPV1 agonist) increased in wild-type DED mice, and consistently, only this strain displayed DED-induced pain signs. Wild-type DED mice exhibited nerve degeneration throughout the corneal epithelium, whereas TRPV1-knockout DED mice only developed a reduction in the most superficial nerve endings that failed to propagate to the deeper subbasal corneal nerves. Pharmacologic TRPV1 blockade reproduced these findings in wild-type DED mice, whereas CD4+ T cells from both strains were equally pathogenic when transferred, ruling out a T-cell-mediated effect of TRPV1 deficiency. These data show that ocular desiccation triggers superficial corneal nerve damage in DED, but proximal propagation of axonal degeneration requires TRPV1 expression. Local inflammation sensitized TRPV1 channels, which increased ocular pain. Thus, ocular TRPV1 overactivation drives DED-associated corneal nerve impairment.
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Affiliation(s)
- Manuela Pizzano
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Alexia Vereertbrugghen
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Agostina Cernutto
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Florencia Sabbione
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Irene A Keitelman
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Carolina M Shiromizu
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Douglas Vera Aguilar
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Federico Fuentes
- Confocal Microscopy Unit, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Mirta N Giordano
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Analía S Trevani
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina
| | - Jeremías G Galletti
- Innate Immunity Laboratory, Institute of Experimental Medicine (CONICET/National Academy of Medicine of Buenos Aires), Buenos Aires, Argentina.
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Keller M, Mergler S, Li A, Zahn I, Paulsen F, Garreis F. Thermosensitive TRP Channels Are Functionally Expressed and Influence the Lipogenesis in Human Meibomian Gland Cells. Int J Mol Sci 2024; 25:4043. [PMID: 38612853 PMCID: PMC11012639 DOI: 10.3390/ijms25074043] [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: 03/05/2024] [Revised: 03/28/2024] [Accepted: 03/30/2024] [Indexed: 04/14/2024] Open
Abstract
While the involvement of thermosensitive transient receptor potential channels (TRPs) in dry eye disease (DED) has been known for years, their expression in the meibomian gland (MG) has never been investigated. This study aims to show their expression and involvement in the lipogenesis of the MG, providing a possible new drug target in the treatment of DED. Our RT-PCR, Western blot and immunofluorescence analysis showed the expression of TRPV1, TRPV3, TRPV4 and TRPM8 in the MG at the gene and the protein level. RT-PCR also showed gene expression of TRPV2 but not TRPA1. Calcium imaging and planar patch-clamping performed on an immortalized human meibomian gland epithelial cell line (hMGECs) demonstrated increasing whole-cell currents after the application of capsaicin (TRPV1) or icilin (TRPM8). Decreasing whole-cell currents could be registered after the application of AMG9810 (TRPV1) or AMTB (TRPM8). Oil red O staining on hMGECs showed an increase in lipid expression after TRPV1 activation and a decrease after TRPM8 activation. We conclude that thermo-TRPs are expressed at the gene and the protein level in MGs. Moreover, TRPV1 and TRPM8's functional expression and their contribution to their lipid expression could be demonstrated. Therefore, TRPs are potential drug targets and their clinical relevance in the therapy of meibomian gland dysfunction requires further investigation.
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Affiliation(s)
- Melina Keller
- Department of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 19, 91054 Erlangen, Germany (F.P.)
| | - Stefan Mergler
- Department of Ophthalmology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 13353 Berlin, Germany; (S.M.); (A.L.)
| | - Aruna Li
- Department of Ophthalmology, Charité—Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin and Humboldt-Universität zu Berlin, 13353 Berlin, Germany; (S.M.); (A.L.)
| | - Ingrid Zahn
- Department of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 19, 91054 Erlangen, Germany (F.P.)
| | - Friedrich Paulsen
- Department of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 19, 91054 Erlangen, Germany (F.P.)
| | - Fabian Garreis
- Department of Functional and Clinical Anatomy, Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), Universitätsstraße 19, 91054 Erlangen, Germany (F.P.)
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Velasco E, Zaforas M, Acosta MC, Gallar J, Aguilar J. Ocular surface information seen from the somatosensory thalamus and cortex. J Physiol 2024; 602:1405-1426. [PMID: 38457332 DOI: 10.1113/jp285008] [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: 05/16/2023] [Accepted: 02/20/2024] [Indexed: 03/10/2024] Open
Abstract
Ocular Surface (OS) somatosensory innervation detects external stimuli producing perceptions, such as pain or dryness, the most relevant symptoms in many OS pathologies. Nevertheless, little is known about the central nervous system circuits involved in these perceptions, and how they integrate multimodal inputs in general. Here, we aim to describe the thalamic and cortical activity in response to OS stimulation of different modalities. Electrophysiological extracellular recordings in anaesthetized rats were used to record neural activity, while saline drops at different temperatures were applied to stimulate the OS. Neurons were recorded in the ophthalmic branch of the trigeminal ganglion (TG, 49 units), the thalamic VPM-POm nuclei representing the face (Th, 69 units) and the primary somatosensory cortex (S1, 101 units). The precise locations for Th and S1 neurons receiving OS information are reported here for the first time. Interestingly, all recorded nuclei encode modality both at the single neuron and population levels, with noxious stimulation producing a qualitatively different activity profile from other modalities. Moreover, neurons responding to new combinations of stimulus modalities not present in the peripheral TG subsequently appear in Th and S1, being organized in space through the formation of clusters. Besides, neurons that present higher multimodality display higher spontaneous activity. These results constitute the first anatomical and functional characterization of the thalamocortical representation of the OS. Furthermore, they provide insight into how information from different modalities gets integrated from the peripheral nervous system into the complex cortical networks of the brain. KEY POINTS: Anatomical location of thalamic and cortical ocular surface representation. Thalamic and cortical neuronal responses to multimodal stimulation of the ocular surface. Increasing functional complexity along trigeminal neuroaxis. Proposal of a new perspective on how peripheral activity shapes central nervous system function.
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Affiliation(s)
- Enrique Velasco
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
- Laboratory of Ion Channel Research, VIB-KU Leuven Center for Brain & Disease Research, Leuven, Belgium
- Neuroscience in Physiotherapy (NiP), Independent Research Group, Elche, Spain
- The European University of Brain and Technology, San Juan de Alicante, Spain
| | - Marta Zaforas
- Laboratorio de Neurofisiología Experimental, Unidad de Investigación, Hospital Nacional de Parapléjicos SESCAM, Toledo, Spain
- Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Spain
| | - M Carmen Acosta
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
- The European University of Brain and Technology, San Juan de Alicante, Spain
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
- The European University of Brain and Technology, San Juan de Alicante, Spain
- Instituto de Investigación Sanitaria y Biomédica de Alicante, San Juan de Alicante, Spain
| | - Juan Aguilar
- Laboratorio de Neurofisiología Experimental, Unidad de Investigación, Hospital Nacional de Parapléjicos SESCAM, Toledo, Spain
- Instituto de Investigación Sanitaria de Castilla-La Mancha (IDISCAM), Spain
- Grupo de Investigación Multidisciplinar en Cuidados, Facultad de Fisioterapia y Enfermería, Universidad de Castilla-La Mancha, Toledo, Spain
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Chubanov V, Köttgen M, Touyz RM, Gudermann T. TRPM channels in health and disease. Nat Rev Nephrol 2024; 20:175-187. [PMID: 37853091 DOI: 10.1038/s41581-023-00777-y] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 09/25/2023] [Indexed: 10/20/2023]
Abstract
Different cell channels and transporters tightly regulate cytoplasmic levels and the intraorganelle distribution of cations. Perturbations in these processes lead to human diseases that are frequently associated with kidney impairment. The family of melastatin-related transient receptor potential (TRPM) channels, which has eight members in mammals (TRPM1-TRPM8), includes ion channels that are highly permeable to divalent cations, such as Ca2+, Mg2+ and Zn2+ (TRPM1, TRPM3, TRPM6 and TRPM7), non-selective cation channels (TRPM2 and TRPM8) and monovalent cation-selective channels (TRPM4 and TRPM5). Three family members contain an enzymatic protein moiety: TRPM6 and TRPM7 are fused to α-kinase domains, whereas TRPM2 is linked to an ADP-ribose-binding NUDT9 homology domain. TRPM channels also function as crucial cellular sensors involved in many physiological processes, including mineral homeostasis, blood pressure, cardiac rhythm and immunity, as well as photoreception, taste reception and thermoreception. TRPM channels are abundantly expressed in the kidney. Mutations in TRPM genes cause several inherited human diseases, and preclinical studies in animal models of human disease have highlighted TRPM channels as promising new therapeutic targets. Here, we provide an overview of this rapidly evolving research area and delineate the emerging role of TRPM channels in kidney pathophysiology.
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Affiliation(s)
- Vladimir Chubanov
- Walther-Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany.
| | - Michael Köttgen
- Renal Division, Department of Medicine, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- CIBSS - Centre for Integrative Biological Signalling Studies, Freiburg, Germany
| | - Rhian M Touyz
- Research Institute of McGill University Health Centre, McGill University, Montreal, Quebec, Canada
| | - Thomas Gudermann
- Walther-Straub Institute of Pharmacology and Toxicology, LMU Munich, Munich, Germany.
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Camacho-Ordonez A, Cervantes-Arriaga A, Rodríguez-Violante M, Hernandez-Medrano AJ, Somilleda-Ventura SA, Pérez-Cano HJ, Nava-Castañeda Á, Guerrero-Berger O. Is there any correlation between alpha-synuclein levels in tears and retinal layer thickness in Parkinson's disease? Eur J Ophthalmol 2024; 34:252-259. [PMID: 37151018 DOI: 10.1177/11206721231173725] [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] [Indexed: 05/09/2023]
Abstract
PURPOSE To determine the total alpha-synuclein (αSyn) reflex tears and its association with retinal layers thickness in Parkinson's disease (PD). METHODS Fifty-two eyes of 26 PD subjects and 52 eyes of age-and sex-matched healthy controls were included. Total αSyn in reflex tears was quantified using a human total αSyn enzyme-linked immunosorbent assay (ELISA) kit. The retinal thickness was evaluated with spectral-domain optical coherence tomography. The Movement Disorder Society-Unified Parkinsońs Disease Rating Scale (MDS-UPDRS), Non-Motor Symptoms Scale (NMSS), and Montreal Cognitive Assessment (MoCA) were used to assess motor, non-motor, and cognition. RESULTS In PD, total αSyn levels were increased compared to control subjects [1.76pg/mL (IQR 1.74-1.80) vs 1.73pg/mL (IQR 1.70-1.77), p < 0.004]. The nerve fiber layer, ganglion cell layer, internal plexiform layer, inner nuclear layer, and outer nuclear layer were thinner in PD in comparison with controls (p < 0.05). The outer plexiform layer and retinal pigment epithelium were thicker in PD (p < 0.05). The total αSyn levels positively correlated with the central volume of the inner nuclear layer (r = 0.357, p = 0.009). CONCLUSION Total αSyn reflex tear levels were increased in subjects with PD compared to controls. PD patients showed significant thinning of the inner retinal layers and thickening of outer retinal layers in comparison with controls. Total αSyn levels positively correlate with the central volume of the inner nuclear layer in PD. The combination of these biomarkers might have a possible role as a diagnostic tool in PD subjects.
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Affiliation(s)
- Azyadeh Camacho-Ordonez
- Neuro-ophthalmology Clinic, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
- Anterior Segment Department, Fundacion Hospital Nuestra Señora de la Luz, IAP, Mexico City, Mexico
| | - Amin Cervantes-Arriaga
- Movement Disorder Clinic, National Institute of Neurology and Neurosurgery, Mexico City, Mexico
| | | | | | | | - Hector J Pérez-Cano
- Biomedical Research Center, Fundacion Hospital Nuestra Señora de la Luz, IAP, Mexico City, Mexico
| | - Ángel Nava-Castañeda
- Oculoplastics Department, Instituto de Oftalmologia Fundacion Conde de Valenciana IAP, Mexico City, Mexico
| | - Oscar Guerrero-Berger
- Anterior Segment Department, Fundacion Hospital Nuestra Señora de la Luz, IAP, Mexico City, Mexico
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Feng J, Yang L, Ran L, Qi X, Wang X, Zhang Y, Zou Z, Liu T, Wang X, Yu Y, Sun X, Zhou Q. Loss of TRPM8 Exacerbate Herpes Simplex Keratitis Infection in Mice by Promoting the Infiltration of CD11b+ Ly6G+ Cells and Increasing the Viral Load in the Cornea. Invest Ophthalmol Vis Sci 2023; 64:24. [PMID: 38117245 PMCID: PMC10741096 DOI: 10.1167/iovs.64.15.24] [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: 04/14/2023] [Accepted: 10/30/2023] [Indexed: 12/21/2023] Open
Abstract
Purpose To reveal the role of transient receptor potential cation subfamily M member 8 (TRPM8) channels in herpes simplex keratitis (HSK). Methods HSK models were established using TRPM8 knockout (TRPM8-/-) mice and their wild-type (WT) littermates. The infected corneas were graded and harvested to evaluate the mRNA levels of inflammatory factors through quantitative real-time polymerase chain reaction (RT-PCR), as well as the infiltration of inflammatory cells through immunofluorescence staining and flow cytometry. Viral titers were determined by plaque assay and absolute quantitative method. RNA-sequencing was conducted to elucidate the transcriptome of corneal epithelium in response to TRPM8 knockout after infection. The anti-inflammatory effect of TRPM8 agonist menthol was documented via subconjunctival administration. Results Compared to their wild-type counterparts, TRPM8-deficient mice exhibited exacerbated infection symptoms and thicker corneas in HSK models. Infection in TRPM8-deficient mice resulted in significant lymphocyte infiltration, primarily consisting of Ly6G+ CD11b+ cells. Additionally, TRPM8-deficient mice displayed increased levels of corneal viral titers after infection, along with decreased expression of interferon-stimulated genes (ISGs). Subconjunctival administration of menthol effectively alleviated infection-induced symptoms and Ly6G+ CD11b+ cell infiltration in herpes simplex virus type 1 (HSV-1)-treated mice. Conclusions TRPM8 promoted host resistance to HSV-1 infection by suppressing the accumulation of Ly6G+ CD11b+ cells and virus replication. These findings suggest that targeting TRPM8 could be valuable for therapeutic interventions against HSV-1 infections.
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Affiliation(s)
- Jing Feng
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Lingling Yang
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Lili Ran
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
- Qingdao University Medical College, Qingdao University, Qingdao, China
| | - Xia Qi
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Xiaolei Wang
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Yangyang Zhang
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Zongzheng Zou
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Ting Liu
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Xiaochuan Wang
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Yang Yu
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Xiaodong Sun
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Qingjun Zhou
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
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Harrell CR, Feulner L, Djonov V, Pavlovic D, Volarevic V. The Molecular Mechanisms Responsible for Tear Hyperosmolarity-Induced Pathological Changes in the Eyes of Dry Eye Disease Patients. Cells 2023; 12:2755. [PMID: 38067183 PMCID: PMC10706334 DOI: 10.3390/cells12232755] [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: 08/20/2023] [Revised: 11/18/2023] [Accepted: 11/27/2023] [Indexed: 12/18/2023] Open
Abstract
Dry eye disease (DED) is a multifactorial disorder of the lacrimal system and ocular surface, characterized by a deficiency in the quality and/or quantity of the tear fluid. The multifactorial nature of DED encompasses a number of interconnected underlying pathologies, including loss of homeostasis, instability and hyperosmolarity of the tears, and the induction and propagation of detrimental inflammatory responses in the eyes, which finally results in the development of neurosensory dysfunction and visual disruption. Dryness, grittiness, scratchiness, discomfort, inflammation, burning, watering, ocular fatigue, pain, and decreased functional visual acuity are common symptoms of DED. Eye dysfunction drastically attenuates patients' quality of life. Accordingly, a better understanding of the pathogenic processes that regulate the development and progression of DED is crucially important for the establishment of new and more effective DED-related treatment approaches, which would significantly improve the quality of life of DED patients. Since the process of osmoregulation, which guards the ocular surface epithelia and maintains normal vision, is affected when the osmolarity of the tears is greater than that of the epithelial cells, tear hyperosmolarity (THO) is considered an initial, important step in the development, progression, and aggravation of DED. In order to delineate the role of THO in the pathogenesis of DED, in this review article, we summarize current knowledge related to the molecular mechanisms responsible for the development of THO-induced pathological changes in the eyes of DED patients, and we briefly discuss the therapeutic potential of hypo-osmotic eye drops in DED treatment.
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Affiliation(s)
- Carl Randall Harrell
- Regenerative Processing Plant, LLC, 34176 US Highway 19 N, Palm Harbor, FL 34684, USA;
| | - Lisa Feulner
- Advanced Eye Care & Aesthetics, 104 Plumtree Rd Suite 107, Bel Air, MD 21015, USA;
| | - Valentin Djonov
- Institute of Anatomy, University of Bern, Baltzerstrasse 2, 3012 Bern, Switzerland;
| | - Dragica Pavlovic
- Departments of Genetics and Microbiology and Immunology, Center for Harm Reduction of Biological and Chemical Hazards, Faculty of Medical Sciences, University of Kragujevac, 69 Svetozar Markovic Street, 34000 Kragujevac, Serbia;
| | - Vladislav Volarevic
- Departments of Genetics and Microbiology and Immunology, Center for Harm Reduction of Biological and Chemical Hazards, Faculty of Medical Sciences, University of Kragujevac, 69 Svetozar Markovic Street, 34000 Kragujevac, Serbia;
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Pastor-Zaplana JÁ, Gallar J, Acosta MC. Functional Changes of the Ocular Surface Sensory Nerves Due to Contact Lens Use in Young Symptomatic and Asymptomatic Users. Invest Ophthalmol Vis Sci 2023; 64:12. [PMID: 37938935 PMCID: PMC10637199 DOI: 10.1167/iovs.64.14.12] [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: 04/20/2023] [Accepted: 10/18/2023] [Indexed: 11/10/2023] Open
Abstract
Purpose The purpose of this study was to analyze the differences in corneal sensory nerve functionality in young asymptomatic (CL-A) and symptomatic (CL-S) contact lens (CL) users. Methods CL wearers (23.8 ± 1.0 years, n = 31) were classified as CL-S with an Ocular Surface Disease Index (OSDI) ≥ 13 (n = 14) or CL-A. Users of eye glasses (EG; 24.5 ± 0.8 years, n = 29) with OSDI < 13 participated as controls. The sensations evoked by mechanical, chemical (gas esthesiometer), and cold (4°C saline drops) stimuli were measured using the Visual Analogue Scales (VASs). Moreover, tear volume, tear break up time (TBUT), blinking frequency (BF), and ocular surface temperature (OST; IR thermography) were also measured. Results Mechanical and chemical stimuli produced similar scores in the CL-A and EG participants, although the CL-A subjects referred to stronger irritation (p < 0.05). Likewise, the VAS intensity in response to cold stimuli did not differ between CL-A and EG subjects, while the ability to detect cold was significantly worse in CL-S users (p < 0.05). CL-A users had a similar tear volume, a higher BF (p < 0.01) and shorter TBUT (p < 0.001) to EG wearers, and blinking and TBUT were also altered significantly in CL-S users (p < 0.01). Interestingly, the OST was significantly lower in CL-A users (p < 0.05) than in EG wearers, but not in CL-S users. Conclusions Using CLs modifies corneal sensitivity, blinking and tearing in young volunteers. Even if they have yet to develop clinical signs of inflammation, they display changes in corneal sensitivity consistent with the sensitization of corneal nociceptors and the inhibition cold thermoreceptors, phenomena that occur under inflammatory conditions. The differences in corneal sensitivity and OST between CL-A and CL-S users could reflect the extent of nerve damage and inflammation at the ocular surface.
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Affiliation(s)
- José Ángel Pastor-Zaplana
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Spain
- Departamento de Patología y Cirugía, Universidad Miguel Hernández de Elche, Sant Joan d'Alacant, Spain
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Spain
- Instituto de Investigación Biomédica y Sanitaria de Alicante, Alicante, Spain
| | - M. Carmen Acosta
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, Sant Joan d'Alacant, Spain
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11
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Daeschler SC, Woo JH, Hussein I, Ali A, Borschel GH. Corneal Neurotization: Preoperative Patient Workup and Surgical Decision-making. PLASTIC AND RECONSTRUCTIVE SURGERY-GLOBAL OPEN 2023; 11:e5334. [PMID: 37829104 PMCID: PMC10566830 DOI: 10.1097/gox.0000000000005334] [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: 02/09/2023] [Accepted: 08/24/2023] [Indexed: 10/14/2023]
Abstract
Background The use of sensory nerve transfers to the anesthetic cornea has transformed the treatment of neurotrophic keratopathy by restoring ocular surface sensation and activating dysfunctional epithelial repair mechanisms. However, despite numerous reports on surgical techniques, there is a scarcity of information on the interdisciplinary management, preoperative assessment, and surgical decision-making, which are equally critical to treatment success. Methods This Special Topic presents a standardized, interdisciplinary preoperative workup based on our 10-year experience with corneal neurotization in 32 eyes of patients with neurotrophic keratopathy. Results Our assessment includes a medical history review, ophthalmic evaluation, and systematic facial sensory donor nerve mapping for light touch and pain modalities. This approach enables evidence-based patient selection, optimal surgery timing, and suitable donor nerve identification, including backup options. Conclusions Based on a decade-long experience, this special topic highlights the importance of interdisciplinary collaboration and provides a practical roadmap for optimizing patient selection and surgical decision-making in patients undergoing corneal neurotization.
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Affiliation(s)
- Simeon C. Daeschler
- From the SickKids Research Institute, Neuroscience and Mental Health Program, Toronto, Ontario, Canada
- Department of Hand, Plastic and Reconstructive Surgery, Burn Center, Department of Plastic and Hand Surgery, University of Heidelberg, BG Trauma Hospital, Ludwigshafen, Germany
| | - Jyh Haur Woo
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada
- Singapore National Eye Centre, Singapore, Singapore
| | - Isra Hussein
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada
| | - Asim Ali
- Department of Ophthalmology and Vision Sciences, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario, Canada
| | - Gregory H. Borschel
- From the SickKids Research Institute, Neuroscience and Mental Health Program, Toronto, Ontario, Canada
- Division of Plastic and Reconstructive Surgery, The Hospital for Sick Children, Toronto, Ontario, Canada
- Department of Surgery, Indiana University School of Medicine, Indianapolis, Ind
- Department of Ophthalmology, Indiana University School of Medicine, Indianapolis, Ind
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12
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Gyenes A, Tapasztó Z, Quirce S, Luna C, Frutos-Rincón L, Gallar J, Acosta MC, Kovács I. Cyclosporine A Decreases Dryness-Induced Hyperexcitability of Corneal Cold-Sensitive Nerve Terminals. Int J Mol Sci 2023; 24:13025. [PMID: 37629206 PMCID: PMC10455570 DOI: 10.3390/ijms241613025] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 08/09/2023] [Accepted: 08/17/2023] [Indexed: 08/27/2023] Open
Abstract
Cyclosporine A (CsA) is used for the treatment of dry eye (DE) with good clinical results, improving tear secretion and decreasing subjective symptoms. These effects are attributed to the improved tear film dynamics, but there are no data on the effect of CsA on the abnormal sensory nerve activity characteristic in DE. Our purpose was to evaluate the CsA effect on the enhanced activity of corneal cold thermoreceptors in a tear-deficient DE animal model using in vitro extracellular recording of cold thermoreceptors nerve terminal impulses (NTIs) before and in the presence of CsA. NTI shape was also analyzed. Blinking frequency and tearing rate were also measured in awake animals before and after topical CsA. CsA increased the tearing and blinking of treated animals. CsA significantly decreased the peak response to cold of cold thermoreceptors. Neither their spontaneous NTIs discharge rate nor their cooling threshold were modified. CsA also seemed to reverse some of the changes in NTI shape induced by tear deficiency. These data suggest that, at least in part, the beneficial clinical effects of CsA in DE can be attributed to a direct effect on sensory nerve endings, although the precise mechanisms underlying this effect need further studies to be fully clarified.
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Affiliation(s)
- Andrea Gyenes
- Department of Ophthalmology, Faculty of Medicine, Semmelweis University, 1085 Budapest, Hungary
| | - Zsófia Tapasztó
- Department of Ophthalmology, Faculty of Medicine, Semmelweis University, 1085 Budapest, Hungary
| | - Susana Quirce
- Instituto de Neurociencias, Universidad Miguel Hernández—CSIC, 03550 San Juan de Alicante, Spain (C.L.); (L.F.-R.); (M.C.A.)
| | - Carolina Luna
- Instituto de Neurociencias, Universidad Miguel Hernández—CSIC, 03550 San Juan de Alicante, Spain (C.L.); (L.F.-R.); (M.C.A.)
| | - Laura Frutos-Rincón
- Instituto de Neurociencias, Universidad Miguel Hernández—CSIC, 03550 San Juan de Alicante, Spain (C.L.); (L.F.-R.); (M.C.A.)
- Instituto de Investigación Sanitaria y Biomédica de Alicante-ISABIAL, 03010 Alicante, Spain
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernández—CSIC, 03550 San Juan de Alicante, Spain (C.L.); (L.F.-R.); (M.C.A.)
- Instituto de Investigación Sanitaria y Biomédica de Alicante-ISABIAL, 03010 Alicante, Spain
| | - M. Carmen Acosta
- Instituto de Neurociencias, Universidad Miguel Hernández—CSIC, 03550 San Juan de Alicante, Spain (C.L.); (L.F.-R.); (M.C.A.)
| | - Illés Kovács
- Department of Ophthalmology, Faculty of Medicine, Semmelweis University, 1085 Budapest, Hungary
- Department of Ophthalmology, Weill Cornell Medical College, New York, NY 10021, USA
- Department of Clinical Ophthalmology, Faculty of Health Sciences, Semmelweis University, 1088 Budapest, Hungary
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Frutos-Rincón L, Luna C, Aleixandre-Carrera F, Velasco E, Diaz-Tahoces A, Meseguer V, Gallar J, Acosta MC. The Contribution of TRPA1 to Corneal Thermosensitivity and Blink Regulation in Young and Aged Mice. Int J Mol Sci 2023; 24:12620. [PMID: 37628800 PMCID: PMC10454529 DOI: 10.3390/ijms241612620] [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: 06/22/2023] [Revised: 07/31/2023] [Accepted: 08/04/2023] [Indexed: 08/27/2023] Open
Abstract
The role of TRPA1 in the thermosensitivity of the corneal cold thermoreceptor nerve endings was studied in young and aged mice. The contribution of the TRPA1-dependent activity to basal tearing and thermally-evoked blink was also explored. The corneal cold thermoreceptors' activity was recorded extracellularly in young (5-month-old) and aged (18-month-old) C57BL/6WT (WT) and TRPA1-/- knockout (TRPA1-KO) mice at basal temperature (34 °C) and during cooling (15 °C) and heating (45 °C) ramps. The blink response to cold and heat stimulation of the ocular surface and the basal tearing rate were also measured in young animals using orbicularis oculi muscle electromyography (OOemg) and phenol red threads, respectively. The background activity at 34 °C and the cooling- and heating-evoked responses of the cold thermoreceptors were similar in WT and TRPA1-KO animals, no matter the age. Similar to the aged WT mice, in the young and aged TRPA1-KO mice, most of the cold thermoreceptors presented low frequency background activity, a low cooling threshold, and a sluggish response to heating. The amplitude and duration of the OOemg signals correlated with the magnitude of the induced thermal change in the WT but not in the TRPA1-KO mice. The basal tearing was similar in the TRPA1-KO and WT mice. The electrophysiological data suggest that the TRPA1-dependent nerve activity, which declines with age, contributes to detecting the warming of the ocular surface and also to integrating the thermally-evoked reflex blink.
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Affiliation(s)
- Laura Frutos-Rincón
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (C.L.); (F.A.-C.); (E.V.); (A.D.-T.); (V.M.); (J.G.)
| | - Carolina Luna
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (C.L.); (F.A.-C.); (E.V.); (A.D.-T.); (V.M.); (J.G.)
| | - Fernando Aleixandre-Carrera
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (C.L.); (F.A.-C.); (E.V.); (A.D.-T.); (V.M.); (J.G.)
| | - Enrique Velasco
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (C.L.); (F.A.-C.); (E.V.); (A.D.-T.); (V.M.); (J.G.)
| | - Ariadna Diaz-Tahoces
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (C.L.); (F.A.-C.); (E.V.); (A.D.-T.); (V.M.); (J.G.)
| | - Víctor Meseguer
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (C.L.); (F.A.-C.); (E.V.); (A.D.-T.); (V.M.); (J.G.)
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (C.L.); (F.A.-C.); (E.V.); (A.D.-T.); (V.M.); (J.G.)
- Instituto de Investigación Biomédica y Sanitaria de Alicante, 03010 Alicante, Spain
| | - M. Carmen Acosta
- Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (C.L.); (F.A.-C.); (E.V.); (A.D.-T.); (V.M.); (J.G.)
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Pertusa M, Solorza J, Madrid R. Molecular determinants of TRPM8 function: key clues for a cool modulation. Front Pharmacol 2023; 14:1213337. [PMID: 37388453 PMCID: PMC10301734 DOI: 10.3389/fphar.2023.1213337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2023] [Accepted: 05/30/2023] [Indexed: 07/01/2023] Open
Abstract
Cold thermoreceptor neurons detect temperature drops with highly sensitive molecular machinery concentrated in their peripheral free nerve endings. The main molecular entity responsible for cold transduction in these neurons is the thermo-TRP channel TRPM8. Cold, cooling compounds such as menthol, voltage, and osmolality rises activate this polymodal ion channel. Dysregulation of TRPM8 activity underlies several physiopathological conditions, including painful cold hypersensitivity in response to axonal damage, migraine, dry-eye disease, overactive bladder, and several forms of cancer. Although TRPM8 could be an attractive target for treating these highly prevalent diseases, there is still a need for potent and specific modulators potentially suitable for future clinical trials. This goal requires a complete understanding of the molecular determinants underlying TRPM8 activation by chemical and physical agonists, inhibition by antagonists, and the modulatory mechanisms behind its function to guide future and more successful treatment strategies. This review recapitulates information obtained from different mutagenesis approaches that have allowed the identification of specific amino acids in the cavity comprised of the S1-S4 and TRP domains that determine modulation by chemical ligands. In addition, we summarize different studies revealing specific regions within the N- and C-terminus and the transmembrane domain that contribute to cold-dependent TRPM8 gating. We also highlight the latest milestone in the field: cryo-electron microscopy structures of TRPM8, which have provided a better comprehension of the 21 years of extensive research in this ion channel, shedding light on the molecular bases underlying its modulation, and promoting the future rational design of novel drugs to selectively regulate abnormal TRPM8 activity under pathophysiological conditions.
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Affiliation(s)
- María Pertusa
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile
- Millennium Nucleus for the Study of Pain (MiNuSPain), Santiago, Chile
| | - Jocelyn Solorza
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile
- Centro de Bioinformática, Simulación y Modelado (CBSM), Facultad de Ingeniería, Universidad de Talca, Talca, Chile
| | - Rodolfo Madrid
- Departamento de Biología, Facultad de Química y Biología, Universidad de Santiago de Chile, Santiago, Chile
- Millennium Nucleus of Ion Channel-Associated Diseases (MiNICAD), Santiago, Chile
- Millennium Nucleus for the Study of Pain (MiNuSPain), Santiago, Chile
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15
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Szallasi A. "ThermoTRP" Channel Expression in Cancers: Implications for Diagnosis and Prognosis (Practical Approach by a Pathologist). Int J Mol Sci 2023; 24:9098. [PMID: 37240443 PMCID: PMC10219044 DOI: 10.3390/ijms24109098] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2023] [Revised: 05/16/2023] [Accepted: 05/18/2023] [Indexed: 05/28/2023] Open
Abstract
Temperature-sensitive transient receptor potential (TRP) channels (so-called "thermoTRPs") are multifunctional signaling molecules with important roles in cell growth and differentiation. Several "thermoTRP" channels show altered expression in cancers, though it is unclear if this is a cause or consequence of the disease. Regardless of the underlying pathology, this altered expression may potentially be used for cancer diagnosis and prognostication. "ThermoTRP" expression may distinguish between benign and malignant lesions. For example, TRPV1 is expressed in benign gastric mucosa, but is absent in gastric adenocarcinoma. TRPV1 is also expressed both in normal urothelia and non-invasive papillary urothelial carcinoma, but no TRPV1 expression has been seen in invasive urothelial carcinoma. "ThermoTRP" expression can also be used to predict clinical outcomes. For instance, in prostate cancer, TRPM8 expression predicts aggressive behavior with early metastatic disease. Furthermore, TRPV1 expression can dissect a subset of pulmonary adenocarcinoma patients with bad prognosis and resistance to a number of commonly used chemotherapeutic agents. This review will explore the current state of this rapidly evolving field with special emphasis on immunostains that can already be added to the armoire of diagnostic pathologists.
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Affiliation(s)
- Arpad Szallasi
- Department of Pathology and Experimental Cancer Research, Semmelweis University, 1085 Budapest, Hungary
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16
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Generation of a TRPM8 knockout hESC line (WAe009-A-A) derived from H9 using CRISPR/Cas9. Stem Cell Res 2023; 67:103040. [PMID: 36796252 DOI: 10.1016/j.scr.2023.103040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2022] [Revised: 01/11/2023] [Accepted: 01/30/2023] [Indexed: 02/09/2023] Open
Abstract
The transient receptor potential cation channel subfamily M member 8 (TRPM8) is a kind of non-selective cation channel which controls Ca2+ homeostasis. Mutations in TRPM8 were related to dry eye diseases (DED). Here we constructed a TRPM8 knockout cell line WAe009-A-A from the original embryonic stem cell line H9 using CRISPR/Cas9 technology, which maybe helpful for exploring the pathogenesis of DED. WAe009-A-A cells possess stem cell morphology and pluripotency as well as normal karyotype, and have the ability of differentiating into three germ layers in vitro.
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17
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Association between mask-associated dry eye (MADE) and corneal sensations. Sci Rep 2023; 13:1625. [PMID: 36709342 PMCID: PMC9884133 DOI: 10.1038/s41598-022-23994-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2022] [Accepted: 11/08/2022] [Indexed: 01/29/2023] Open
Abstract
To determine the risk of mask-associated dry eye (MADE), we investigated the fluorescein tear break-up time (FBUT), ocular surface temperature and blood flow, along with corneal sensitivity, in mask wearers. We enrolled 60 mask wearers (mean age, 27.1 ± 5.2 years) and then measured FBUT, corneal temperature and conjunctival blood flow without wearing masks (no mask), with masks, and with taped masks. We defined MADE as the condition in which dry eye symptoms appeared and the FBUT with mask was less than 5 s. The FBUT with a mask was significantly shorter compared to the no mask and taped mask groups (P < 0.01 and P < 0.05). The corneal temperature difference and conjunctival blood flow difference were significantly higher after wearing a mask than after wearing a taped mask (P < 0.01). Of the 60 subjects, 13 were diagnosed with MADE. Pain sensitivity and the Ocular Surface Disease Index (P < 0.05 and P < 0.01) were significantly higher in the MADE group, with the FBUT without masks (P < 0.05) significantly shorter than in the non-MADE group. MADE may be associated with corneal hypersensitivity. Wearing masks decreased FBUT and increased ocular surface temperature and blood flow. Taping the top edge of masks prevented these changes. Fitting masks properly may reduce MADE risk.
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18
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Ran L, Feng J, Qi X, Liu T, Qi B, Jiang K, Zhang Z, Yu Y, Zhou Q, Xie L. Effect of TRPM8 Functional Loss on Corneal Epithelial Wound Healing in Mice. Invest Ophthalmol Vis Sci 2023; 64:19. [PMID: 36692471 PMCID: PMC9896868 DOI: 10.1167/iovs.64.1.19] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Purpose To reveal the role of cold-sensing transient receptor potential melastatin 8 (TRPM8) channels in corneal epithelial wound healing. Methods Cold sensitivity, tear production, corneal thickness, and corneal opacity assessments were used to evaluate the effect of Trpm8 knockout on the ocular surface. A corneal epithelial wounding model was generated by scraping the corneal epithelium once or multiple times using C57BL/6J (wild-type [WT]) and Trpm8-/- mice. The processes of corneal epithelial repair and corneal epitheliopathy were observed and recorded. Corneas were collected for sequencing, immunofluorescence staining, hematoxylin and eosin staining, and quantitative PCR. Results The perception of coldness, basal tear secretion, and corneal thickness were decreased in young Trpm8-/- mice compared with those in WT mice, except for the corneal sensitivity. Corneal opacity and increased corneal thickness were observed in aged Trpm8-/- mice. TRPM8 deficiency promoted corneal epithelial wound closure, consistent with the observed increase in Ki67-positive epithelial cells, and the pharmacological activation of TRPM8 in WT mice delayed corneal re-epithelization. After subjecting mice to multiple injuries, squamous metaplasia emerged in Trpm8-/- corneas, as verified by cytokeratin-1 and small proline-rich protein 1B-positive staining. The IFN-β and IFN-γ signaling pathways were significantly activated in Trpm8-/- mice, which was confirmed based on the up-regulated expression of the key mediators, signal transducer and activator of transcription-1 and phosphor-signal transducer and activator of transcription-1, as well as the induction of IFN-stimulated genes, compared with levels in WT mice. Conclusions In corneal wound healing, the loss of TRPM8 function could promote epithelial repair, but predispose the cornea to epithelial lesions.
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Affiliation(s)
- Lili Ran
- Qingdao University Medical College, Qingdao University, Qingdao, China,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Jing Feng
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Xia Qi
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Ting Liu
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Benxiang Qi
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Kai Jiang
- Qingdao University Medical College, Qingdao University, Qingdao, China,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China,Department of Ophthalmology, The Affiliated Yantai Yuhuangding Hospital of Qingdao University, Yantai, China
| | - Zhenzhen Zhang
- Qingdao University Medical College, Qingdao University, Qingdao, China,State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Yang Yu
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Qingjun Zhou
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
| | - Lixin Xie
- State Key Laboratory Cultivation Base, Shandong Provincial Key Laboratory of Ophthalmology, Eye Institute of Shandong First Medical University, Qingdao, China
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Katagiri A, Tsubota K, Mikuzuki L, Nakamura S, Toyofuku A, Kato T, Bereiter DA, Iwata K. Tear secretion by Diquafosol suppresses the excitability of trigeminal brainstem nuclear complex neurons by reducing excessive P2Y 2 expression in the trigeminal ganglion in dry eye rats. Neurosci Res 2023; 191:66-76. [PMID: 36657726 DOI: 10.1016/j.neures.2023.01.003] [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: 09/05/2022] [Revised: 01/06/2023] [Accepted: 01/15/2023] [Indexed: 01/18/2023]
Abstract
The P2Y2 receptor agonist, diquafosol sodium, is commonly used to treat the signs and symptoms of dry eye disease (DE) patients. Although diquafosol improves tear film stability, the neural mechanisms underlying the reduction in ocular pain are not well defined. This study determined if repeated application of diquafosol reduces the sensitization of nociceptive neurons in the lower trigeminal brainstem nuclear complex (TBNC) via peripheral P2Y2 mechanisms in a rat model for DE. Diquafosol was applied to the ocular surface daily for 28 days, starting at day 0 or day 14, after exorbital gland removal. The number of eyeblinks, P2Y2-immunoreactive neurons in the trigeminal ganglion (TG), and correlates of TBNC neural excitability (i.e., cFos protein and phosphorylated extracellular signal-regulated kinase (pERK) expression) were assessed in male rats. Diquafosol increased spontaneous tear volume and reduced the number of ocular surface-evoked eyeblinks in DE rats. Fluorogold-labeled TG neurons that supply the cornea expressed P2Y2. The number of P2Y2-immunoreactive neurons was increased in DE rats and suppressed by diquafosol. Diquafosol also reduced the number of cFos- and pERK-immunoreactive neurons in the TBNC in DE rats. These findings suggest that diquafosol, regardless of late-phase treatment, relieves ocular nociception in DE by reducing peripheral P2Y2 expression.
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Affiliation(s)
- Ayano Katagiri
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita-shi, Osaka 565-0871, Japan.
| | - Kazuo Tsubota
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan; Tsubota Laboratory, Inc., 34 Shinanomachi, Shinjuku-ku, Tokyo 160-0016, Japan.
| | - Lou Mikuzuki
- Division of Geriatric Dentistry, Department of Critical Care Dentistry, Kanagawa Dental University, 82 Inaoka-cho, Yokosuka-shi, Kanagawa 238-8580, Japan.
| | - Shigeru Nakamura
- Department of Ophthalmology, Keio University School of Medicine, 35 Shinanomachi, Shinjuku-ku, Tokyo 160-8582, Japan.
| | - Akira Toyofuku
- Department of Psychosomatic Dentistry, Tokyo Medical and Dental University (TMDU) Graduate School, 1-5-45 Yushima Bunkyo-ku, Tokyo, 113-8510, Japan.
| | - Takafumi Kato
- Department of Oral Physiology, Osaka University Graduate School of Dentistry, 1-8 Yamadaoka, Suita-shi, Osaka 565-0871, Japan.
| | - David A Bereiter
- Department of Diagnostic and Biological Sciences, University of Minnesota School of Dentistry, Minneapolis, MN 55455, USA.
| | - Koichi Iwata
- Department of Physiology, Nihon University School of Dentistry, 1-8-13 Kandasurugadai, Chiyoda-ku, Tokyo 101-8310, Japan.
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Progress in the Structural Basis of thermoTRP Channel Polymodal Gating. Int J Mol Sci 2023; 24:ijms24010743. [PMID: 36614186 PMCID: PMC9821180 DOI: 10.3390/ijms24010743] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2022] [Revised: 12/26/2022] [Accepted: 12/27/2022] [Indexed: 01/03/2023] Open
Abstract
The thermosensory transient receptor potential (thermoTRP) family of ion channels is constituted by several nonselective cation channels that are activated by physical and chemical stimuli functioning as paradigmatic polymodal receptors. Gating of these ion channels is achieved through changes in temperature, osmolarity, voltage, pH, pressure, and by natural or synthetic chemical compounds that directly bind to these proteins to regulate their activity. Given that thermoTRP channels integrate diverse physical and chemical stimuli, a thorough understanding of the molecular mechanisms underlying polymodal gating has been pursued, including the interplay between stimuli and differences between family members. Despite its complexity, recent advances in cryo-electron microscopy techniques are facilitating this endeavor by providing high-resolution structures of these channels in different conformational states induced by ligand binding or temperature that, along with structure-function and molecular dynamics, are starting to shed light on the underlying allosteric gating mechanisms. Because dysfunctional thermoTRP channels play a pivotal role in human diseases such as chronic pain, unveiling the intricacies of allosteric channel gating should facilitate the development of novel drug-based resolving therapies for these disorders.
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21
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Safonova TN, Medvedeva ES, Medvedeva SL. [Neuropathic pain in dry eye syndrome. Part 1. Pathophysiological mechanisms of pain formation]. Vestn Oftalmol 2023; 139:93-99. [PMID: 37638578 DOI: 10.17116/oftalma202313904193] [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] [Indexed: 08/29/2023]
Abstract
The review details the features and mechanisms of the formation of various types of pain. The emphasis is placed on the occurrence of pain syndrome in various ophthalmological diseases, particularly in dry eye syndrome. The article also presents literature data on the role of cytokines in the formation of a neuroinflammatory cascade affecting damage to corneal nerve fibers and the development of pain syndrome, which is a characteristic feature of a subtype of dry eye disease - burning eye syndrome.
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Affiliation(s)
- T N Safonova
- Krasnov Research Institute of Eye Diseases, Moscow, Russia
| | - E S Medvedeva
- Krasnov Research Institute of Eye Diseases, Moscow, Russia
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22
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Sekhon AS, He B, Iovieno A, Yeung SN. Pathophysiology of Corneal Endothelial Cell Loss in Dry Eye Disease and Other Inflammatory Ocular Disorders. Ocul Immunol Inflamm 2023; 31:21-31. [PMID: 34678119 DOI: 10.1080/09273948.2021.1980808] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023]
Abstract
PURPOSE Dry eye disease (DED) and other inflammatory ocular disorders have been reported to be associated with decreased corneal endothelial cell density (CECD), however the mechanism of underlying endothelial cell loss remains unknown. METHODS We conducted a comprehensive literature search of English-written publications on dry eye disease, corneal endothelial cell loss, Sjögren's syndrome, and Graft Vs Host Disease (GVHD), to review the effects of DED and other inflammatory ocular surface conditions on CECD. RESULTS A total of 78 studies were included in our study. Loss of corneal neurotrophic support, cytotoxic stress, and a heightened immune response, all of which may occur secondarily to a common causative agent such as inflammation, are major contributors to reduced CECD. CONCLUSION More studies are needed to determine how the interrelated pathways of altered corneal nerve function and upregulated expression of inflammatory activity influence corneal endothelial cell loss.
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Affiliation(s)
- Amardeep S Sekhon
- Department of Anesthesiology, Pharmacology and Therapeutics, Faculty of Medicine, University of British Columbia, Vancouver, Canada
| | - Bonnie He
- Faculty of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | - Alfonso Iovieno
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada
| | - Sonia N Yeung
- Department of Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada
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23
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Merino ML, Belmonte J, Rosas J, Acosta MC, Gallar J, Belmonte C. Maximal tear secretion evoked by controlled stimulation of corneal sensory nerves in healthy individuals and dry eye subjects. Ocul Surf 2023; 27:80-88. [PMID: 36396021 DOI: 10.1016/j.jtos.2022.11.005] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 11/10/2022] [Accepted: 11/10/2022] [Indexed: 11/16/2022]
Abstract
PURPOSE To measure, the tear flow changes evoked in healthy subjects and dry eye disease (DED) patients by controlled sensory stimulation of the eye surface with i-Onion™, a new stimulation device. METHODS Sensory corneal nerves were stimulated with an instrument (i-Onion™) that ejects puffs of CO2 gas (99.9%) at 200 ml·min-1 for 3s, delivered 5 mm from the cornea. Using Schirmer test strips, tear volumes were measured over 3 min in the cornea of one eye before (basal tear volume -BTV) and in the other eye after stimulation of the sensory nerves with CO2 (stimulated tear volume -STV). These measurements were obtained from a control group of adults of either sex (17 students aged 20-30 and 29 subjects without signs of dry eye aged 25-61), a cohort of DED patients (aged 34-75) that included 12 asymptomatic, suspected DED subjects (Schirmer <7 mm and/or TBUT <10s), and 30 Sjögren's syndrome (SS) patients. RESULTS CO2 stimulation significantly increased the tear volume (BTV = 14.6 ± 1.0 mm, STV = 19.0 ± 1.1 mm: n = 46) in 78% of control subjects, reflecting a mean tear reserve volume (TRV = STV-BTV) of 4.4 ± 0.8 mm. Individual differences were wide, and while no increase in reflex tearing was evoked in 30% of subjects with a BTV >10 mm, the remaining 70% responded vigorously to stimulation, even those with a BTV >18 mm. Asymptomatic DED subjects displayed weaker responses to CO2 stimulation, with lower STVs. Both the BTV and STV of SS patients were low, significantly below those of the healthy controls. CONCLUSIONS Measuring the rise in reflex tearing volume evoked by controlled corneal stimulation provides objective information about the tear glands' secretory capacity in health and disease.
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Affiliation(s)
- María L Merino
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain; Oftalmología, Hospital de la Marina Baixa, Villajoyosa, Spain
| | - Javier Belmonte
- Oftalmología, Hospital General Universitario de Alicante, Alicante, Spain
| | - José Rosas
- Reumatología, Hospital de la Marina Baixa, Villajoyosa, Spain
| | - M Carmen Acosta
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain; Instituto de Investigación Biomédica y Sanitaria de Alicante, San Juan de Alicante, Spain
| | - Carlos Belmonte
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain.
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Hernández-Ortego P, Torres-Montero R, de la Peña E, Viana F, Fernández-Trillo J. Validation of Six Commercial Antibodies for the Detection of Heterologous and Endogenous TRPM8 Ion Channel Expression. Int J Mol Sci 2022; 23:ijms232416164. [PMID: 36555804 PMCID: PMC9784522 DOI: 10.3390/ijms232416164] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 12/12/2022] [Accepted: 12/15/2022] [Indexed: 12/23/2022] Open
Abstract
TRPM8 is a non-selective cation channel expressed in primary sensory neurons and other tissues, including the prostate and urothelium. Its participation in different physiological and pathological processes such as thermoregulation, pain, itch, inflammation and cancer has been widely described, making it a promising target for therapeutic approaches. The detection and quantification of TRPM8 seems crucial for advancing the knowledge of the mechanisms underlying its role in these pathophysiological conditions. Antibody-based techniques are commonly used for protein detection and quantification, although their performance with many ion channels, including TRPM8, is suboptimal. Thus, the search for reliable antibodies is of utmost importance. In this study, we characterized the performance of six TRPM8 commercial antibodies in three immunodetection techniques: Western blot, immunocytochemistry and immunohistochemistry. Different outcomes were obtained for the tested antibodies; two of them proved to be successful in detecting TRPM8 in the three approaches while, in the conditions tested, the other four were acceptable only for specific techniques. Considering our results, we offer some insight into the usefulness of these antibodies for the detection of TRPM8 depending on the methodology of choice.
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25
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Eidet JR, Chen X, Ræder S, Badian RA, Utheim TP. Seasonal variations in presenting symptoms and signs of dry eye disease in Norway. Sci Rep 2022; 12:21046. [PMID: 36473933 PMCID: PMC9726935 DOI: 10.1038/s41598-022-25557-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Accepted: 11/30/2022] [Indexed: 12/12/2022] Open
Abstract
The study investigated the seasonal variations of presenting symptoms and signs of dry eye disease (DED) in Norway. 652 consecutive DED patients examined between August 2012 and May 2015 in Oslo, Norway, were included. Presenting symptoms and signs were related to the season according to when each patient was examined. Weather report data from the examination day were compared with the presenting symptoms and signs. Oslo's mean seasonal temperatures during spring, summer, fall, and winter were 6.4 °C, 15.6 °C, 9.3 °C, and - 2.1 °C, respectively. Dry eye severity level and self-reported symptoms measured by the Ocular surface disease index questionnaire did not differ between seasons. Schirmer I was lower during summer than in other seasons (P < 0.01). The percentage of patients with a pathological tear meniscus height (< 0.2 mm) was higher during fall (P < 0.01) and lower during winter (P < 0.05) compared to the other seasons. Signs and symptoms of DED generally did not correlate with weather report data, although intraocular pressure was weakly associated with mean daily air temperature (r = - 0.22; P < 0.001). Neither dry eye severity level nor dry eye symptoms differ between seasons in Oslo, Norway. However, some parameters for assessing DED show seasonal variations (Schirmer I and tear meniscus height), which are essential to consider when examining patients with DED.
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Affiliation(s)
- Jon Roger Eidet
- The Norwegian Dry Eye Clinic, Oslo, Norway ,grid.55325.340000 0004 0389 8485Department of Ophthalmology, Oslo University Hospital, Nydalen, P.O. box 4956, 0424 Oslo, Norway
| | - Xiangjun Chen
- The Norwegian Dry Eye Clinic, Oslo, Norway ,grid.452467.6Department of Ophthalmology, Hospital of Southern Norway, Arendal, Norway ,grid.55325.340000 0004 0389 8485Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Sten Ræder
- The Norwegian Dry Eye Clinic, Oslo, Norway ,grid.55325.340000 0004 0389 8485Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Reza A. Badian
- The Norwegian Dry Eye Clinic, Oslo, Norway ,grid.55325.340000 0004 0389 8485Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway
| | - Tor P. Utheim
- The Norwegian Dry Eye Clinic, Oslo, Norway ,grid.55325.340000 0004 0389 8485Department of Ophthalmology, Oslo University Hospital, Nydalen, P.O. box 4956, 0424 Oslo, Norway ,grid.452467.6Department of Ophthalmology, Hospital of Southern Norway, Arendal, Norway ,grid.55325.340000 0004 0389 8485Department of Medical Biochemistry, Oslo University Hospital, Oslo, Norway ,grid.412835.90000 0004 0627 2891Department of Ophthalmology, Stavanger University Hospital, Oslo, Norway ,grid.459157.b0000 0004 0389 7802Department of Ophthalmology, Vestre Viken Hospital Trust, Drammen, Norway ,grid.412414.60000 0000 9151 4445Department of Research and Development, Oslo Metropolitan University, Oslo, Norway ,grid.7914.b0000 0004 1936 7443Department of Clinical Medicine, Faculty of Medicine, University of Bergen, Bergen, Norway ,grid.18883.3a0000 0001 2299 9255Department of Quality and Health Technology, The Faculty of Health Sciences, University of Stavanger, Stavanger, Norway ,grid.5510.10000 0004 1936 8921Department of Oral Biology, Faculty of Dentistry, University of Oslo, Oslo, Norway ,grid.463530.70000 0004 7417 509XNational Centre for Optics, Vision and Eye Care, Department of Optometry, Radiography and Lighting Design, Faculty of Health Sciences, University of South-Eastern Norway, Kongsberg, Norway ,grid.23048.3d0000 0004 0417 6230Department of Health and Nursing Science, The Faculty of Health and Sport Sciences, University of Agder, Grimstad, Norway
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Zhang Z, Kang L, Yan X, Leng Z, Fang K, Chen T, Xu M. Global Trends and Hotspots of Transient Receptor Potential Melastatin 8 Research from 2002 to 2021: A Bibliometric Analysis. J Pain Res 2022; 15:3881-3892. [DOI: 10.2147/jpr.s393582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2022] [Accepted: 12/06/2022] [Indexed: 12/14/2022] Open
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Yin Y, Zhang F, Feng S, Butay KJ, Borgnia MJ, Im W, Lee SY. Activation mechanism of the mouse cold-sensing TRPM8 channel by cooling agonist and PIP 2. Science 2022; 378:eadd1268. [PMID: 36227998 PMCID: PMC9795508 DOI: 10.1126/science.add1268] [Citation(s) in RCA: 23] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The transient receptor potential melastatin 8 (TRPM8) channel is the primary molecular transducer responsible for the cool sensation elicited by menthol and cold in mammals. TRPM8 activation is controlled by cooling compounds together with the membrane lipid phosphatidylinositol 4,5-bisphosphate (PIP2). Our knowledge of cold sensation and the therapeutic potential of TRPM8 for neuroinflammatory diseases and pain will be enhanced by understanding the structural basis of cooling agonist- and PIP2-dependent TRPM8 activation. We present cryo-electron microscopy structures of mouse TRPM8 in closed, intermediate, and open states along the ligand- and PIP2-dependent gating pathway. Our results uncover two discrete agonist sites, state-dependent rearrangements in the gate positions, and a disordered-to-ordered transition of the gate-forming S6-elucidating the molecular basis of chemically induced cool sensation in mammals.
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Affiliation(s)
- Ying Yin
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Feng Zhang
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA
| | - Shasha Feng
- Departments of Biological Sciences, Chemistry, and Bioengineering, Lehigh University, Bethlehem, PA, 18015, USA
| | - Kevin John Butay
- Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Mario J. Borgnia
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA.,Genome Integrity and Structural Biology Laboratory, National Institute of Environmental Health Sciences, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, NC 27709, USA
| | - Wonpil Im
- Departments of Biological Sciences, Chemistry, and Bioengineering, Lehigh University, Bethlehem, PA, 18015, USA
| | - Seok-Yong Lee
- Department of Biochemistry, Duke University School of Medicine, Durham, NC, 27710, USA.,Correspondence to: S.-Y. Lee, , telephone: 919-684-1005
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Asiedu K. Role of ocular surface neurobiology in neuronal-mediated inflammation in dry eye disease. Neuropeptides 2022; 95:102266. [PMID: 35728484 DOI: 10.1016/j.npep.2022.102266] [Citation(s) in RCA: 11] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/17/2021] [Revised: 06/07/2022] [Accepted: 06/08/2022] [Indexed: 01/18/2023]
Abstract
Inflammation is the consequence of dry eye disease regardless of its etiology. Several injurious or harmless processes to the ocular surface neurons promote ocular surface neurogenic inflammation, leading to the vicious cycle of dry eye disease. These processes include the regular release of neuromediators during the conduction of ocular surface sensations, hyperosmolarity-induced ocular surface neuronal damage, neuro-regenerative activities, and neuronal-mediated dendritic cell activities. Neurogenic inflammation appears to be the main culprit, instigating the self-perpetuating inflammation observed in patients with dry eye disease.
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Affiliation(s)
- Kofi Asiedu
- School of Optometry & Vision Science, Faculty of Medicine and Health, University of New South Wales, Sydney, Australia.
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Jahanfar F, Sadofsky L, Morice A, D’Amico M. Nebivolol as a Potent TRPM8 Channel Blocker: A Drug-Screening Approach through Automated Patch Clamping and Ligand-Based Virtual Screening. MEMBRANES 2022; 12:954. [PMID: 36295712 PMCID: PMC9609861 DOI: 10.3390/membranes12100954] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 01/25/2022] [Revised: 09/19/2022] [Accepted: 09/24/2022] [Indexed: 06/16/2023]
Abstract
Transient Receptor Potential Melastatin 8 (TRPM8) from the melastatin TRP channel subfamily is a non-selective Ca2+-permeable ion channel with multimodal gating which can be activated by low temperatures and cooling compounds, such as menthol and icilin. Different conditions such as neuropathic pain, cancer, overactive bladder syndrome, migraine, and chronic cough have been linked to the TRPM8 mode of action. Despite the several potent natural and synthetic inhibitors of TRPM8 that have been identified, none of them have been approved for clinical use. The aim of this study was to discover novel blocking TRPM8 agents using automated patch clamp electrophysiology combined with a ligand-based virtual screening based on the SwissSimilarity platform. Among the compounds we have tested, nebivolol and carvedilol exhibited the greatest inhibitory effect, with an IC50 of 0.97 ± 0.15 µM and 9.1 ± 0.6 µM, respectively. This study therefore provides possible candidates for future drug repurposing and suggests promising lead compounds for further optimization as inhibitors of the TRPM8 ion channel.
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Affiliation(s)
- Farhad Jahanfar
- Di.V.A.L. Toscana S.r.l., Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
- Department of Medical Biotechnologies, University of Siena, 53100 Siena, Italy
| | - Laura Sadofsky
- Centre for Atherothrombosis and Metabolic Disease, Hull York Medical School, University of Hull, Hull HU6 7RX, UK
| | - Alyn Morice
- Respiratory Research Group, Hull York Medical School, Castle Hill Hospital, Cottingham HU16 5JQ, UK
| | - Massimo D’Amico
- Di.V.A.L. Toscana S.r.l., Via Madonna del Piano 6, 50019 Sesto Fiorentino, Italy
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Transient Receptor Potential Channels: Important Players in Ocular Pain and Dry Eye Disease. Pharmaceutics 2022; 14:pharmaceutics14091859. [PMID: 36145607 PMCID: PMC9506338 DOI: 10.3390/pharmaceutics14091859] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2022] [Revised: 08/26/2022] [Accepted: 08/26/2022] [Indexed: 11/20/2022] Open
Abstract
Dry eye disease (DED) is a multifactorial disorder in which the eyes respond to minor stimuli with abnormal sensations, such as dryness, blurring, foreign body sensation, discomfort, irritation, and pain. Corneal pain, as one of DED’s main symptoms, has gained recognition due to its increasing prevalence, morbidity, and the resulting social burden. The cornea is the most innervated tissue in the body, and the maintenance of corneal integrity relies on a rich density of nociceptors, such as polymodal nociceptor neurons, cold thermoreceptor neurons, and mechano-nociceptor neurons. Their sensory responses to different stimulating forces are linked to the specific expression of transient receptor potential (TRP) channels. TRP channels are a group of unique ion channels that play important roles as cellular sensors for various stimuli. These channels are nonselective cation channels with variable Ca2+ selectivity. TRP homologs are a superfamily of 28 different members that are subdivided into 7 different subfamilies based on differences in sequence homology. Many of these subtypes are expressed in the eye on both neuronal and non-neuronal cells, where they affect various stress-induced regulatory responses essential for normal vision maintenance. This article reviews the current knowledge about the expression, function, and regulation of TRPs in ocular surface tissues. We also describe their implication in DED and ocular pain. These findings contribute to evidence suggesting that drug-targeting TRP channels may be of therapeutic benefit in the clinical setting of ocular pain.
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Galor A, Hamrah P, Haque S, Attal N, Labetoulle M. Understanding chronic ocular surface pain: An unmet need for targeted drug therapy. Ocul Surf 2022; 26:148-156. [PMID: 35970433 DOI: 10.1016/j.jtos.2022.08.005] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2022] [Revised: 07/29/2022] [Accepted: 08/09/2022] [Indexed: 10/15/2022]
Abstract
Chronic ocular surface pain (COSP) may be defined as a feeling of pain, perceived as originating from the ocular surface, that persists for >3 months. COSP is a complex multifactorial condition associated with several risk factors that may significantly interfere with an individual's daily activities, resulting in poor quality of life (QoL). COSP is also likely to have a high burden on patients with substantial implications on global healthcare costs. While patients may use varied terminology to describe symptoms of COSP, any ocular surface damage in the ocular sensory apparatus (nociceptive, neuropathic, inflammatory, or combination thereof) resulting in low tear production, chronic inflammation, or nerve abnormalities (functional and/or morphological), is typically associated with COSP. Considering the heterogeneity of this condition, it is highly recommended that advanced multimodal diagnostic tools are utilized to help discern the nociceptive and neuropathic pain pathways in order to provide targeted treatment and effective clinical management. The current article provides an overview of COSP, including its multifactorial pathophysiology, etiology, prevalence, clinical presentation, impact on QoL, diagnosis, current management, and unmet medical needs.
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Affiliation(s)
- Anat Galor
- Surgical Services, Miami Veterans Affairs Medical Centre and Bascom Palmer Eye Institute, University of Miami, Miami, FL, USA
| | - Pedram Hamrah
- Tufts Medical Centre, New England Eye Center, 260 Tremont Street Biewend Building, Boston, MA, USA
| | | | - Nadine Attal
- CHU Paris IdF Ouest - Hôpital Ambroise Paré, 9 avenue Charles de Gaulle, 92100, Boulogne-Billancourt, INSERM U 987 and Université Paris Saclay, France
| | - Marc Labetoulle
- Service d'Ophtalmologie, hôpital Bicêtre, AP-HP, Université Paris Saclay, 94275, Le Kremlin-Bicêtre, France; IMVA-HB/IDMI, CEA, Inserm U1184, 92265, Fontenay-aux-Roses, France.
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Lacripep for the Treatment of Primary Sjögren's-Associated Ocular Surface Disease: Results of the First-In-Human Study. Cornea 2022:00003226-990000000-00084. [PMID: 35942530 PMCID: PMC9895125 DOI: 10.1097/ico.0000000000003091] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 05/21/2022] [Indexed: 02/08/2023]
Abstract
PURPOSE The purpose of this study was to assess the safety, tolerability, dosing, and efficacy of the active 19 amino acid fragment of lacritin (Lacripep), a broad regulator of ocular surface homeostasis, in the treatment of ocular surface disease associated with primary Sjögren's syndrome. METHODS Two hundred four subjects were randomized to receive vehicle, 22 μM Lacripep, or 44 μM Lacripep 3 times daily for 28 days, preceded by a 14-day run-in and followed by 14-day washout. Outcome measures were corneal fluorescein staining (CFS), lissamine conjunctival staining, Schirmer with anesthesia, tear break-up time, SANDE scoring, and visual analog scale assessment of symptoms. RESULTS This study established the safety and tolerability of topical treatment with Lacripep in patients with primary Sjögren's syndrome. There were few adverse events: Only mild irritation was found in less than 3 percent of patients dosed with Lacripep. Total CFS and Eye Dryness Score were not significantly changed at day 28. Post hoc analysis of patients with Eye Dryness Severity scores of 60 or greater at baseline revealed significant improvements in inferior CFS at 14 and 28 days and complaints of burning and stinging at 14 days. Significant improvement in regional lissamine conjunctival staining was seen at 14 and 28 days. CONCLUSIONS This first-in-human study of Lacripep in patients with primary Sjögren's syndrome demonstrated clinically significant improvements in specific signs and symptoms on which to base future studies. This study established safety and tolerability and potential metrics of efficacy in patients with moderate to severe disease. Further work on appropriate dosing and concentration is ongoing.
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Benzalkonium chloride, a common ophthalmic preservative, compromises rat corneal cold sensitive nerve activity. Ocul Surf 2022; 26:88-96. [DOI: 10.1016/j.jtos.2022.07.012] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2022] [Revised: 07/25/2022] [Accepted: 07/29/2022] [Indexed: 11/15/2022]
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Neuroimmune crosstalk in the cornea: The role of immune cells in corneal nerve maintenance during homeostasis and inflammation. Prog Retin Eye Res 2022; 91:101105. [PMID: 35868985 DOI: 10.1016/j.preteyeres.2022.101105] [Citation(s) in RCA: 20] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 07/01/2022] [Accepted: 07/04/2022] [Indexed: 12/29/2022]
Abstract
In the cornea, resident immune cells are in close proximity to sensory nerves, consistent with their important roles in the maintenance of nerves in both homeostasis and inflammation. Using in vivo confocal microscopy in humans, and ex vivo immunostaining and fluorescent reporter mice to visualize corneal sensory nerves and immune cells, remarkable progress has been made to advance our understanding of the physical and functional interactions between corneal nerves and immune cells. In this review, we summarize and discuss recent studies relating to corneal immune cells and sensory nerves, and their interactions in health and disease. In particular, we consider how disrupted corneal nerve axons can induce immune cell activity, including in dendritic cells, macrophages and other infiltrating cells, directly and/or indirectly by releasing neuropeptides such as substance P and calcitonin gene-related peptide. We summarize growing evidence that the role of corneal intraepithelial immune cells is likely different in corneal wound healing versus other inflammatory-dominated conditions. The role of different types of macrophages is also discussed, including how stromal macrophages with anti-inflammatory phenotypes communicate with corneal nerves to provide neuroprotection, while macrophages with pro-inflammatory phenotypes, along with other infiltrating cells including neutrophils and CD4+ T cells, can be inhibitory to corneal re-innervation. Finally, this review considers the bidirectional interactions between corneal immune cells and corneal nerves, and how leveraging this interaction could represent a potential therapeutic approach for corneal neuropathy.
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Corneal nerves and their role in dry eye pathophysiology. Exp Eye Res 2022; 222:109191. [PMID: 35850173 DOI: 10.1016/j.exer.2022.109191] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2022] [Revised: 06/15/2022] [Accepted: 07/11/2022] [Indexed: 12/11/2022]
Abstract
As the cornea is densely innervated, its nerves are integral not only to its structure but also to its pathophysiology. Corneal integrity depends on a protective tear film that is maintained by corneal sensation and the reflex arcs that control tearing and blinking. Furthermore, corneal nerves promote epithelial growth and local immunoregulation. Thus, corneal nerves constitute pillars of ocular surface homeostasis. Conversely, the abnormal tear film in dry eye favors corneal epithelial and nerve damage. The ensuing corneal nerve dysfunction contributes to dry eye progression, ocular pain and discomfort, and other neuropathic symptoms. Recent evidence from clinical studies and animal models highlight the significant but often overlooked neural dimension of dry eye pathophysiology. Herein, we review the anatomy and physiology of corneal nerves before exploring their role in the mechanisms of dry eye disease.
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36
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TRPV1 + sensory nerves modulate corneal inflammation after epithelial abrasion via RAMP1 and SSTR5 signaling. Mucosal Immunol 2022; 15:867-881. [PMID: 35680973 DOI: 10.1038/s41385-022-00533-8] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2021] [Revised: 04/25/2022] [Accepted: 05/24/2022] [Indexed: 02/04/2023]
Abstract
Timely initiation and termination of inflammatory response after corneal epithelial abrasion is critical for the recovery of vision. The cornea is innervated with rich sensory nerves with highly dense TRPV1 nociceptors. However, the roles of TRPV1+ sensory neurons in corneal inflammation after epithelial abrasion are not completely understood. Here, we found that depletion of TRPV1+ sensory nerves using resiniferatoxin (RTX) and blockade of TRPV1 using AMG-517 delayed corneal wound closure and enhanced the infiltration of neutrophils and γδ T cells to the wounded cornea after epithelial abrasion. Furthermore, depletion of TRPV1+ sensory nerves increased the number and TNF-α production of corneal CCR2+ macrophages and decreased the number of corneal CCR2- macrophages and IL-10 production. In addition, the TRPV1+ sensory nerves inhibited the recruitment of neutrophils and γδ T cells to the cornea via RAMP1 and SSTR5 signaling, decreased the responses of CCR2+ macrophages via RAMP1 signaling, and increased the responses of CCR2- macrophages via SSTR5 signaling. Collectively, our results suggest that the TRPV1+ sensory nerves suppress inflammation to support corneal wound healing via RAMP1 and SSTR5 signaling, revealing potential approaches for improving defective corneal wound healing in patients with sensory neuropathy.
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37
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Velasco E, Delicado‐Miralles M, Hellings PW, Gallar J, Van Gerven L, Talavera K. Epithelial and sensory mechanisms of nasal hyperreactivity. Allergy 2022; 77:1450-1463. [PMID: 35174893 DOI: 10.1111/all.15259] [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: 10/30/2021] [Revised: 02/06/2022] [Accepted: 02/14/2022] [Indexed: 11/28/2022]
Abstract
"Nasal hyperreactivity" is a key feature in various phenotypes of upper airway diseases, whereby reactions of the nasal epithelium to diverse chemical and physical stimuli are exacerbated. In this review, we illustrate how nasal hyperreactivity can result from at least three types of mechanisms: (1) impaired barrier function, (2) hypersensitivity to external and endogenous stimuli, and (3) potentiation of efferent systems. We describe the known molecular basis of hyperreactivity related to the functional impairment of epithelial cells and somatosensory innervation, and indicate that the thermal, chemical, and mechanical sensors determining hyperreactivity in humans remain to be identified. We delineate research directions that may provide new insights into nasal hyperreactivity associated with rhinitis/rhinosinusitis pathophysiology and therapeutics. The elucidation of the molecular mechanisms underlying nasal hyperreactivity is essential for the treatment of rhinitis according to the precepts of precision medicine.
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Affiliation(s)
- Enrique Velasco
- Instituto de Neurociencias Universidad Miguel Hernández‐CSIC San Juan de Alicante Spain
- The European University of Brain and Technology‐Neurotech EU San Juan de Alicante Spain
| | | | - Peter W. Hellings
- Department of Otorhinolaryngology University Hospitals Leuven Leuven Belgium
| | - Juana Gallar
- Instituto de Neurociencias Universidad Miguel Hernández‐CSIC San Juan de Alicante Spain
- The European University of Brain and Technology‐Neurotech EU San Juan de Alicante Spain
- Instituto de Investigación Sanitaria y Biomédica de Alicante San Juan de Alicante Spain
| | - Laura Van Gerven
- Department of Otorhinolaryngology University Hospitals Leuven Leuven Belgium
- Department of Microbiology, Immunology and transplantation, Allergy and Clinical Immunology Research Unit KU Leuven Leuven Belgium
- Department of Neurosciences, Experimental Otorhinolaryngology, Rhinology Research KU Leuven Leuven Belgium
| | - Karel Talavera
- Laboratory of Ion Channel Research Department of Cellular and Molecular Medicine KU Leuven, VIB‐KU Leuven Center for Brain & Disease Research Leuven Belgium
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38
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Yang S, Wu Y, Wang C, Jin X. Ocular Surface Ion-Channels Are Closely Related to Dry Eye: Key Research Focus on Innovative Drugs for Dry Eye. Front Med (Lausanne) 2022; 9:830853. [PMID: 35308542 PMCID: PMC8927818 DOI: 10.3389/fmed.2022.830853] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2021] [Accepted: 02/07/2022] [Indexed: 11/13/2022] Open
Abstract
Abundant ion-channels, including various perceptual receptors, chloride channels, purinergic receptor channels, and water channels that exist on the ocular surface, play an important role in the pathogenesis of dry eye. Channel-targeting activators or inhibitor compounds, which have shown positive effects in in vivo and in vitro experiments, have become the focus of the dry eye drug research and development, and individual compounds have been applied in clinical experimental treatment. This review summarized various types of ion-channels on the ocular surface related to dry eye, their basic functions, and spatial distribution, and discussed basic and clinical research results of various channel receptor regulatory compounds. Therefore, further elucidating the relationship between ion-channels and dry eye will warrant research of dry eye targeted drug therapy.
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Affiliation(s)
- Shuo Yang
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Yaying Wu
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - ChunYang Wang
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
| | - Xiuming Jin
- Eye Center, Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
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39
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Frutos-Rincón L, Gómez-Sánchez JA, Íñigo-Portugués A, Acosta MC, Gallar J. An Experimental Model of Neuro-Immune Interactions in the Eye: Corneal Sensory Nerves and Resident Dendritic Cells. Int J Mol Sci 2022; 23:ijms23062997. [PMID: 35328417 PMCID: PMC8951464 DOI: 10.3390/ijms23062997] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2022] [Revised: 02/28/2022] [Accepted: 03/04/2022] [Indexed: 12/04/2022] Open
Abstract
The cornea is an avascular connective tissue that is crucial, not only as the primary barrier of the eye but also as a proper transparent refractive structure. Corneal transparency is necessary for vision and is the result of several factors, including its highly organized structure, the physiology of its few cellular components, the lack of myelinated nerves (although it is extremely innervated), the tightly controlled hydration state, and the absence of blood and lymphatic vessels in healthy conditions, among others. The avascular, immune-privileged tissue of the cornea is an ideal model to study the interactions between its well-characterized and dense sensory nerves (easily accessible for both focal electrophysiological recording and morphological studies) and the low number of resident immune cell types, distinguished from those cells migrating from blood vessels. This paper presents an overview of the corneal structure and innervation, the resident dendritic cell (DC) subpopulations present in the cornea, their distribution in relation to corneal nerves, and their role in ocular inflammatory diseases. A mouse model in which sensory axons are constitutively labeled with tdTomato and DCs with green fluorescent protein (GFP) allows further analysis of the neuro-immune crosstalk under inflammatory and steady-state conditions of the eye.
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Affiliation(s)
- Laura Frutos-Rincón
- Instituto de Neurociencias, Universidad Miguel Hernández—Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (A.Í.-P.); (M.C.A.); (J.G.)
- The European University of Brain and Technology-NeurotechEU, 03550 San Juan de Alicante, Spain
| | - José Antonio Gómez-Sánchez
- Instituto de Neurociencias, Universidad Miguel Hernández—Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (A.Í.-P.); (M.C.A.); (J.G.)
- Correspondence: ; Tel.: +34-965-91-9594
| | - Almudena Íñigo-Portugués
- Instituto de Neurociencias, Universidad Miguel Hernández—Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (A.Í.-P.); (M.C.A.); (J.G.)
| | - M. Carmen Acosta
- Instituto de Neurociencias, Universidad Miguel Hernández—Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (A.Í.-P.); (M.C.A.); (J.G.)
- The European University of Brain and Technology-NeurotechEU, 03550 San Juan de Alicante, Spain
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernández—Consejo Superior de Investigaciones Científicas, 03550 San Juan de Alicante, Spain; (L.F.-R.); (A.Í.-P.); (M.C.A.); (J.G.)
- The European University of Brain and Technology-NeurotechEU, 03550 San Juan de Alicante, Spain
- Instituto de Investigación Biomédica y Sanitaria de Alicante, 03010 Alicante, Spain
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40
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Reeh PW, Fischer MJM. Nobel somatosensations and pain. Pflugers Arch 2022; 474:405-420. [PMID: 35157132 PMCID: PMC8924131 DOI: 10.1007/s00424-022-02667-x] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2021] [Revised: 01/17/2022] [Accepted: 01/18/2022] [Indexed: 12/12/2022]
Abstract
The Nobel prices 2021 for Physiology and Medicine have been awarded to David Julius and Ardem Patapoutian "for their discoveries of receptors for temperature and touch", TRPV1 and PIEZO1/2. The present review tells the past history of the capsaicin receptor, covers further selected TRP channels, TRPA1 in particular, and deals with mechanosensitivity in general and mechanical hyperalgesia in particular. Other achievements of the laureates and translational aspects of their work are shortly treated.
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41
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Tear film and ocular surface neuropeptides: Characteristics, synthesis, signaling and implications for ocular surface and systemic diseases. Exp Eye Res 2022; 218:108973. [PMID: 35149082 DOI: 10.1016/j.exer.2022.108973] [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: 08/05/2021] [Revised: 12/14/2021] [Accepted: 02/01/2022] [Indexed: 01/13/2023]
Abstract
Ocular surface neuropeptides are vital molecules primarily involved in maintaining ocular surface integrity and homeostasis. They also serve as communication channels between the nervous system and the immune system, maintaining the homeostasis of the ocular surface. Tear film and ocular surface neuropeptides have a role in disease often due to abnormalities in their synthesis (either high or low production), signaling through defective receptors, or both. This creates imbalances in otherwise normal physiological processes. They have been observed to be altered in many ocular surface and systemic diseases including dry eye disease, ocular allergy, keratoconus, LASIK-induced dry eye, pterygium, neurotrophic keratitis, corneal graft rejection, microbial keratitis, headaches and diabetes. This review examines the characteristics of neuropeptides, their synthesis and their signaling through G-protein coupled receptors. The review also explores the types of neuropeptides within the tears and ocular surface, and how they change in ocular and systemic diseases.
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42
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Maksymchuk N, Sakurai A, Cox DN, Cymbalyuk G. Transient and Steady-State Properties of Drosophila Sensory Neurons Coding Noxious Cold Temperature. Front Cell Neurosci 2022; 16:831803. [PMID: 35959471 PMCID: PMC9358291 DOI: 10.3389/fncel.2022.831803] [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: 12/08/2021] [Accepted: 06/09/2022] [Indexed: 12/04/2022] Open
Abstract
Coding noxious cold signals, such as the magnitude and rate of temperature change, play essential roles in the survival of organisms. We combined electrophysiological and computational neuroscience methods to investigate the neural dynamics of Drosophila larva cold-sensing Class III (CIII) neurons. In response to a fast temperature change (-2 to -6°C/s) from room temperature to noxious cold, the CIII neurons exhibited a pronounced peak of a spiking rate with subsequent relaxation to a steady-state spiking. The magnitude of the peak was higher for a higher rate of temperature decrease, while slow temperature decrease (-0.1°C/s) evoked no distinct peak of the spiking rate. The rate of the steady-state spiking depended on the magnitude of the final temperature and was higher at lower temperatures. For each neuron, we characterized this dependence by estimating the temperature of the half activation of the spiking rate by curve fitting neuron's spiking rate responses to a Boltzmann function. We found that neurons had a temperature of the half activation distributed over a wide temperature range. We also found that CIII neurons responded to decrease rather than increase in temperature. There was a significant difference in spiking activity between fast and slow returns from noxious cold to room temperature: The CIII neurons usually stopped activity abruptly in the case of the fast return and continued spiking for some time in the case of the slow return. We developed a biophysical model of CIII neurons using a generalized description of transient receptor potential (TRP) current kinetics with temperature-dependent activation and Ca2+-dependent inactivation. This model recapitulated the key features of the spiking rate responses found in experiments and suggested mechanisms explaining the transient and steady-state activity of the CIII neurons at different cold temperatures and rates of their decrease and increase. We conclude that CIII neurons encode at least three types of cold sensory information: the rate of temperature decrease by a peak of the firing rate, the magnitude of cold temperature by the rate of steady spiking activity, and direction of temperature change by spiking activity augmentation or suppression corresponding to temperature decrease and increase, respectively.
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Affiliation(s)
- Natalia Maksymchuk
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Akira Sakurai
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Daniel N Cox
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States
| | - Gennady Cymbalyuk
- Neuroscience Institute, Georgia State University, Atlanta, GA, United States.,Department of Physics and Astronomy, Georgia State University, Atlanta, GA, United States
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43
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Puja G, Sonkodi B, Bardoni R. Mechanisms of Peripheral and Central Pain Sensitization: Focus on Ocular Pain. Front Pharmacol 2021; 12:764396. [PMID: 34916942 PMCID: PMC8669969 DOI: 10.3389/fphar.2021.764396] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2021] [Accepted: 11/09/2021] [Indexed: 12/14/2022] Open
Abstract
Persistent ocular pain caused by corneal inflammation and/or nerve injury is accompanied by significant alterations along the pain axis. Both primary sensory neurons in the trigeminal nerves and secondary neurons in the spinal trigeminal nucleus are subjected to profound morphological and functional changes, leading to peripheral and central pain sensitization. Several studies using animal models of inflammatory and neuropathic ocular pain have provided insight about the mechanisms involved in these maladaptive changes. Recently, the advent of new techniques such as optogenetics or genetic neuronal labelling has allowed the investigation of identified circuits involved in nociception, both at the spinal and trigeminal level. In this review, we will describe some of the mechanisms that contribute to the perception of ocular pain at the periphery and at the spinal trigeminal nucleus. Recent advances in the discovery of molecular and cellular mechanisms contributing to peripheral and central pain sensitization of the trigeminal pathways will be also presented.
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Affiliation(s)
- Giulia Puja
- Department of Life Sciences, University of Modena and Reggio Emilia, Emilia-Romagna, Italy
| | - Balazs Sonkodi
- Department of Health Sciences and Sport Medicine, University of Physical Education, Budapest, Hungary
| | - Rita Bardoni
- Department of Biomedical, Metabolic and Neural Sciences, University of Modena and Reggio Emilia, Emilia-Romagna, Italy
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44
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Comes N, Gasull X, Callejo G. Proton Sensing on the Ocular Surface: Implications in Eye Pain. Front Pharmacol 2021; 12:773871. [PMID: 34899333 PMCID: PMC8652213 DOI: 10.3389/fphar.2021.773871] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2021] [Accepted: 11/09/2021] [Indexed: 01/15/2023] Open
Abstract
Protons reaching the eyeball from exogenous acidic substances or released from damaged cells during inflammation, immune cells, after tissue injury or during chronic ophthalmic conditions, activate or modulate ion channels present in sensory nerve fibers that innervate the ocular anterior surface. Their identification as well as their role during disease is critical for the understanding of sensory ocular pathophysiology. They are likely to mediate some of the discomfort sensations accompanying several ophthalmic formulations and may represent novel targets for the development of new therapeutics for ocular pathologies. Among the ion channels expressed in trigeminal nociceptors innervating the anterior surface of the eye (cornea and conjunctiva) and annex ocular structures (eyelids), members of the TRP and ASIC families play a critical role in ocular acidic pain. Low pH (pH 6) activates TRPV1, a polymodal ion channel also activated by heat, capsaicin and hyperosmolar conditions. ASIC1, ASIC3 and heteromeric ASIC1/ASIC3 channels present in ocular nerve terminals are activated at pH 7.2–6.5, inducing pain by moderate acidifications of the ocular surface. These channels, together with TRPA1, are involved in acute ocular pain, as well as in painful sensations during allergic keratoconjunctivitis or other ophthalmic conditions, as blocking or reducing channel expression ameliorates ocular pain. TRPV1, TRPA1 and other ion channels are also present in corneal and conjunctival cells, promoting inflammation of the ocular surface after injury. In addition to the above-mentioned ion channels, members of the K2P and P2X ion channel families are also expressed in trigeminal neurons, however, their role in ocular pain remains unclear to date. In this report, these and other ion channels and receptors involved in acid sensing during ocular pathologies and pain are reviewed.
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Affiliation(s)
- Núria Comes
- Neurophysiology Laboratory, Department of Biomedicine, Medical School, Institute of Neurosciences, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Xavier Gasull
- Neurophysiology Laboratory, Department of Biomedicine, Medical School, Institute of Neurosciences, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
| | - Gerard Callejo
- Neurophysiology Laboratory, Department of Biomedicine, Medical School, Institute of Neurosciences, Universitat de Barcelona, Barcelona, Spain.,Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Barcelona, Spain
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45
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Luna C, Quirce S, Aracil-Marco A, Belmonte C, Gallar J, Acosta MC. Unilateral Corneal Insult Also Alters Sensory Nerve Activity in the Contralateral Eye. Front Med (Lausanne) 2021; 8:767967. [PMID: 34869482 PMCID: PMC8634144 DOI: 10.3389/fmed.2021.767967] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Accepted: 10/11/2021] [Indexed: 01/21/2023] Open
Abstract
After the unilateral inflammation or nerve lesion of the ocular surface, the ipsilateral corneal sensory nerve activity is activated and sensitized, evoking ocular discomfort, irritation, and pain referred to the affected eye. Nonetheless, some patients with unilateral ocular inflammation, infection, or surgery also reported discomfort and pain in the contralateral eye. We explored the possibility that such altered sensations in the non-affected eye are due to the changes in their corneal sensory nerve activity in the contralateral, not directly affected eye. To test that hypothesis, we recorded the impulse activity of the corneal mechano- and polymodal nociceptor and cold thermoreceptor nerve terminals in both eyes of guinea pigs, subjected unilaterally to three different experimental conditions (UV-induced photokeratitis, microkeratome corneal surgery, and chronic tear deficiency caused by removal of the main lacrimal gland), and in eyes of naïve animals ex vivo. Overall, after unilateral eye damage, the corneal sensory nerve activity appeared to be also altered in the contralateral eye. Compared with the naïve guinea pigs, animals with unilateral UV-induced mild corneal inflammation, showed on both eyes an inhibition of the spontaneous and stimulus-evoked activity of cold thermoreceptors, and increased activity in nociceptors affecting both the ipsilateral and the contralateral eye. Unilateral microkeratome surgery affected the activity of nociceptors mostly, inducing sensitization in both eyes. The removal of the main lacrimal gland reduced tear volume and increased the cold thermoreceptor activity in both eyes. This is the first direct demonstration that unilateral corneal nerve lesion, especially ocular surface inflammation, functionally affects the activity of the different types of corneal sensory nerves in both the ipsilateral and contralateral eyes. The mechanisms underlying the contralateral affectation of sensory nerves remain to be determined, although available data support the involvement of neuroimmune interactions. The parallel alteration of nerve activity in contralateral eyes has two main implications: a) in the experimental design of both preclinical and clinical studies, where the contralateral eyes cannot be considered as a control; and, b) in the clinical practice, where clinicians must consider the convenience of treating both eyes of patients with unilateral ocular conditions to avoid pain and secondary undesirable effects in the fellow eye.
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Affiliation(s)
- Carolina Luna
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Susana Quirce
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Adolfo Aracil-Marco
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Carlos Belmonte
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain.,Instituto de Investigación Sanitaria y Biomédica de Alicante, San Juan de Alicante, Spain
| | - M Carmen Acosta
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
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46
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Di Donato M, Ostacolo C, Giovannelli P, Di Sarno V, Monterrey IMG, Campiglia P, Migliaccio A, Bertamino A, Castoria G. Therapeutic potential of TRPM8 antagonists in prostate cancer. Sci Rep 2021; 11:23232. [PMID: 34853378 PMCID: PMC8636514 DOI: 10.1038/s41598-021-02675-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/12/2021] [Accepted: 11/22/2021] [Indexed: 12/27/2022] Open
Abstract
Transient receptor potential melastatin-8 (TRPM8) represents an emerging target in prostate cancer, although its mechanism of action remains unclear. Here, we have characterized and investigated the effects of TRPM8 modulators in prostate cancer aggressiveness disclosing the molecular mechanism underlying their biological activity. Patch-clamp and calcium fluorometric assays were used to characterize the synthesized compounds. Androgen-stimulated prostate cancer-derived cells were challenged with the compounds and the DNA synthesis was investigated in a preliminary screening. The most effective compounds were then employed to inhibit the pro-metastatic behavior of in various PC-derived cells, at different degree of malignancy. The effect of the compounds was then assayed in prostate cancer cell-derived 3D model and the molecular targets of selected compounds were lastly identified using transcriptional and non-transcriptional reporter assays. TRPM8 antagonists inhibit the androgen-dependent prostate cancer cell proliferation, migration and invasiveness. They are highly effective in reverting the androgen-induced increase in prostate cancer cell spheroid size. The compounds also revert the proliferation of castrate-resistant prostate cancer cells, provided they express the androgen receptor. In contrast, no effects were recorded in prostate cancer cells devoid of the receptor. Selected antagonists interfere in non-genomic androgen action and abolish the androgen-induced androgen receptor/TRPM8 complex assembly as well as the increase in intracellular calcium levels in prostate cancer cells. Our results shed light in the processes controlling prostate cancer progression and make the transient receptor potential melastatin-8 as a ‘druggable’ target in the androgen receptor-expressing prostate cancers.
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Affiliation(s)
- Marzia Di Donato
- Department of Precision Medicine, School of Medicine, University of Campania 'L. Vanvitelli', Via L. De Crecchio 7, 80138, Naples, Italy
| | - Carmine Ostacolo
- Department of Pharmacy, University Federico II of Naples, Via D. Montesano 49, 80131, Naples, Italy
| | - Pia Giovannelli
- Department of Precision Medicine, School of Medicine, University of Campania 'L. Vanvitelli', Via L. De Crecchio 7, 80138, Naples, Italy
| | - Veronica Di Sarno
- Department of Pharmacy, University of Salerno, Via G.Paolo II, 84084, Fisciano, SA, Italy
| | - Isabel M Gomez Monterrey
- Department of Pharmacy, University Federico II of Naples, Via D. Montesano 49, 80131, Naples, Italy
| | - Pietro Campiglia
- Department of Pharmacy, University of Salerno, Via G.Paolo II, 84084, Fisciano, SA, Italy
| | - Antimo Migliaccio
- Department of Precision Medicine, School of Medicine, University of Campania 'L. Vanvitelli', Via L. De Crecchio 7, 80138, Naples, Italy
| | - Alessia Bertamino
- Department of Pharmacy, University of Salerno, Via G.Paolo II, 84084, Fisciano, SA, Italy.
| | - Gabriella Castoria
- Department of Precision Medicine, School of Medicine, University of Campania 'L. Vanvitelli', Via L. De Crecchio 7, 80138, Naples, Italy.
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47
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Delicado-Miralles M, Velasco E, Díaz-Tahoces A, Gallar J, Acosta MC, Aracil-Marco A. Deciphering the Action of Perfluorohexyloctane Eye Drops to Reduce Ocular Discomfort and Pain. Front Med (Lausanne) 2021; 8:709712. [PMID: 34765614 PMCID: PMC8577568 DOI: 10.3389/fmed.2021.709712] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2021] [Accepted: 09/28/2021] [Indexed: 12/24/2022] Open
Abstract
Perfluorohexyloctane (F6H8) eyedrops have been recently introduced in Europe as a product to treat dry eye disease, based on its ability to reduce tear film instability in Meibomian gland dysfunction and evaporative dry eye disease, although its mechanism of action is still unknown. In the present pilot study, we evaluated the effects of the ocular instillation of a single drop of commercial F6H8 eyedrops in 20 healthy humans (9 women/11 men), measuring: (a) Corneal surface temperature (CST) from infrared video images; (b) tear volume using phenol red threads; (c) blinking frequency; and (d) ocular surface sensations (cold, dryness, pricking, foreign body, burning, itching, gritty, eye fatigue, watering eyes, and light-evoked discomfort sensations; scored using 10 cm Visual Analog Scales), before and 5–60 min after F6H8 or saline treatment. CST decreased and tearing and blinking frequency increased significantly after F6H8 but not after saline solution. When applied unilaterally, CST decreased only in the F6H8-treated eye. No sensations were evoked after F6H8 or saline. The corneal surface temperature reduction produced by topical F6H8 does not evoke conscious ocular sensations but is sufficient to increase the activity of corneal cold thermoreceptors, leading to an increased reflex lacrimation and blinking that may relieve dry eye condition thus reducing ocular discomfort and pain.
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Affiliation(s)
- Miguel Delicado-Miralles
- Cellular and Systems Neurobiology Unit, Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, San Juan de Alicante, Spain
| | - Enrique Velasco
- Cellular and Systems Neurobiology Unit, Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, San Juan de Alicante, Spain.,The European University of Brain and Technology-NeurotechEU, San Juan de Alicante, Spain
| | - Ariadna Díaz-Tahoces
- Cellular and Systems Neurobiology Unit, Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, San Juan de Alicante, Spain.,Instituto de Investigación Sanitaria y Biomédica de Alicante, San Juan de Alicante, Spain
| | - Juana Gallar
- Cellular and Systems Neurobiology Unit, Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, San Juan de Alicante, Spain.,The European University of Brain and Technology-NeurotechEU, San Juan de Alicante, Spain.,Instituto de Investigación Sanitaria y Biomédica de Alicante, San Juan de Alicante, Spain
| | - M Carmen Acosta
- Cellular and Systems Neurobiology Unit, Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, San Juan de Alicante, Spain.,The European University of Brain and Technology-NeurotechEU, San Juan de Alicante, Spain
| | - Adolfo Aracil-Marco
- Cellular and Systems Neurobiology Unit, Instituto de Neurociencias, Universidad Miguel Hernández-Consejo Superior de Investigaciones Científicas, San Juan de Alicante, Spain
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Barros A, Queiruga-Piñeiro J, Lozano-Sanroma J, Alcalde I, Gallar J, Fernández-Vega Cueto L, Alfonso JF, Quirós LM, Merayo-Lloves J. Small fiber neuropathy in the cornea of Covid-19 patients associated with the generation of ocular surface disease. Ocul Surf 2021; 23:40-48. [PMID: 34781021 PMCID: PMC8588585 DOI: 10.1016/j.jtos.2021.10.010] [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: 04/14/2021] [Revised: 10/18/2021] [Accepted: 10/29/2021] [Indexed: 12/17/2022]
Abstract
Purpose To describe the association between Sars-CoV-2 infection and small fiber neuropathy in the cornea identified by in vivo corneal confocal microscopy. Methods Twenty-three patients who had overcome COVID-19 were recruited to this observational retrospective study. Forty-six uninfected volunteers were also recruited and studied as a control group. All subjects were examined under in vivo confocal microscopy to obtain images of corneal subbasal nerve fibers in order to study the presence of neuroma-like structures, axonal beadings and dendritic cells. The Ocular Surface Disease Index (OSDI) questionnaire and Schirmer tear test were used as indicators of Dry Eye Disease (DED) and ocular surface pathology. Results Twenty-one patients (91.31%) presented alterations of the corneal subbasal plexus and corneal tissue consistent with small fiber neuropathy. Images from healthy subjects did not indicate significant nerve fiber or corneal tissue damage. Eight patients reported increased sensations of ocular dryness after COVID-19 infection and had positive DED indicators. Beaded axons were found in 82.60% of cases, mainly in patients reporting ocular irritation symptoms. Neuroma-like images were found in 65.22% patients, more frequently in those with OSDI scores >13. Dendritic cells were found in 69.56% of patients and were more frequent in younger asymptomatic patients. The presence of morphological alterations in patients up to 10 months after recovering from Sars-CoV-2 infection points to the chronic nature of the neuropathy. Conclusions Sars-CoV-2 infection may be inducing small fiber neuropathy in the ocular surface, sharing symptomatology and morphological landmarks with DED and diabetic neuropathy.
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Affiliation(s)
| | | | | | - Ignacio Alcalde
- Instituto Universitario Fernández-Vega, Universidad de Oviedo & Fundación de Investigación Oftalmológica, Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain.
| | - Juana Gallar
- Instituto de Neurociencias, Universidad Miguel Hernández-CSIC, San Juan de Alicante, Spain
| | - Luis Fernández-Vega Cueto
- Instituto Oftalmológico Fernández-Vega, Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain.
| | - José F Alfonso
- Instituto Oftalmológico Fernández-Vega, Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain; Department of Surgery and Medical-Surgical Specialties, Universidad de Oviedo, Oviedo, Spain
| | - Luis M Quirós
- Instituto Universitario Fernández-Vega, Universidad de Oviedo & Fundación de Investigación Oftalmológica, Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain; Department of Functional Biology, Universidad de Oviedo, Oviedo, Spain
| | - Jesús Merayo-Lloves
- Instituto Oftalmológico Fernández-Vega, Oviedo, Spain; Instituto Universitario Fernández-Vega, Universidad de Oviedo & Fundación de Investigación Oftalmológica, Oviedo, Spain; Instituto de Investigación Sanitaria del Principado de Asturias (ISPA), Oviedo, Spain; Department of Surgery and Medical-Surgical Specialties, Universidad de Oviedo, Oviedo, Spain
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Autoimmune Epithelitis and Chronic Inflammation in Sjögren's Syndrome-Related Dry Eye Disease. Int J Mol Sci 2021; 22:ijms222111820. [PMID: 34769250 PMCID: PMC8584177 DOI: 10.3390/ijms222111820] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2021] [Revised: 10/07/2021] [Accepted: 10/09/2021] [Indexed: 12/18/2022] Open
Abstract
Autoimmune epithelitis and chronic inflammation are one of the characteristic features of the immune pathogenesis of Sjögren’s syndrome (SS)-related dry eye disease. Autoimmune epithelitis can cause the dysfunction of the excretion of tear fluid and mucin from the lacrimal glands and conjunctival epithelia and meibum from the meibomian glands. The lacrimal gland and conjunctival epithelia express major histocompatibility complex class II or human leukocyte antigen-DR and costimulatory molecules, acting as nonprofessional antigen-presenting cells for T cell and B cell activation in SS. Ocular surface epithelium dysfunction can lead to dry eye disease in SS. Considering the mechanisms underlying SS-related dry eye disease, this review highlights autoimmune epithelitis of the ocular surface, chronic inflammation, and several other molecules in the tear film, cornea, conjunctiva, lacrimal glands, and meibomian glands that represent potential targets in the treatment of SS-related dry eye disease.
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Constitutive Phosphorylation as a Key Regulator of TRPM8 Channel Function. J Neurosci 2021; 41:8475-8493. [PMID: 34446569 DOI: 10.1523/jneurosci.0345-21.2021] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2021] [Revised: 07/04/2021] [Accepted: 08/13/2021] [Indexed: 11/21/2022] Open
Abstract
In mammals, environmental cold sensing conducted by peripheral cold thermoreceptor neurons mostly depends on TRPM8, an ion channel that has evolved to become the main molecular cold transducer. This TRP channel is activated by cold, cooling compounds, such as menthol, voltage, and rises in osmolality. TRPM8 function is regulated by kinase activity that phosphorylates the channel under resting conditions. However, which specific residues, how this post-translational modification modulates TRPM8 activity, and its influence on cold sensing are still poorly understood. By mass spectrometry, we identified four serine residues within the N-terminus (S26, S29, S541, and S542) constitutively phosphorylated in the mouse ortholog. TRPM8 function was examined by Ca2+ imaging and patch-clamp recordings, revealing that treatment with staurosporine, a kinase inhibitor, augmented its cold- and menthol-evoked responses. S29A mutation is sufficient to increase TRPM8 activity, suggesting that phosphorylation of this residue is a central molecular determinant of this negative regulation. Biophysical and total internal reflection fluorescence-based analysis revealed a dual mechanism in the potentiated responses of unphosphorylated TRPM8: a shift in the voltage activation curve toward more negative potentials and an increase in the number of active channels at the plasma membrane. Importantly, basal kinase activity negatively modulates TRPM8 function at cold thermoreceptors from male and female mice, an observation accounted for by mathematical modeling. Overall, our findings suggest that cold temperature detection could be rapidly and reversibly fine-tuned by controlling the TRPM8 basal phosphorylation state, a mechanism that acts as a dynamic molecular brake of this thermo-TRP channel function in primary sensory neurons.SIGNIFICANCE STATEMENT Post-translational modifications are one of the main molecular mechanisms involved in adjusting the sensitivity of sensory ion channels to changing environmental conditions. Here we show, for the first time, that constitutive phosphorylation of the well-conserved serine 29 within the N-terminal domain negatively modulates TRPM8 channel activity, reducing its activation by agonists and decreasing the number of active channels at the plasma membrane. Basal phosphorylation of TRPM8 acts as a key regulator of its function as the main cold-transduction channel, significantly contributing to the net response of primary sensory neurons to temperature reductions. This reversible and dynamic modulatory mechanism opens new opportunities to regulate TRPM8 function in pathologic conditions where this thermo-TRP channel plays a critical role.
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