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Caminos E, Murillo-Martínez M, García-Belando M, Cabanes-Sanchís JJ, Martinez-Galan JR. Robust expression of the TRPC1 channel associated with photoreceptor loss in the rat retina. Exp Eye Res 2023; 236:109655. [PMID: 37722585 DOI: 10.1016/j.exer.2023.109655] [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: 05/02/2023] [Revised: 07/11/2023] [Accepted: 09/14/2023] [Indexed: 09/20/2023]
Abstract
Baseline intracellular calcium levels are significantly higher in neuronal and glial cells of rat retinas with retinitis pigmentosa (RP). Although this situation could initiate multiple detrimental pathways that lead to cell death, we considered the possibility of TRPC1 being involved in maintaining calcium homeostasis in the retina by acting as a component of store-operated calcium (SOC) channels with special relevance during photoreceptor degeneration. In this study, we examined by Western blot the expression of TRPC1 in healthy control rat retinas (Sprague-Dawley, SD) and retinas with RP (P23H-1 rats). We also analyzed its specific cellular distribution by immunofluorescence to recognize changes during neurodegeneration and to determine whether its presence is consistent with high basal calcium levels and cellular survival in degenerating retinas. We found that TRPC1 immunostaining was widely distributed across the retina in both rat strains, SD and P23H, and its expression levels significantly increased in the retinas with advanced degeneration compared to the age-control SD rats. In the outer retina, TRPC1 immunoreactivity was distributed in pigment epithelium cells, the photoreceptor inner segments of older animals, and the outer plexiform layer. In the inner retina, TRPC1 labeling was detected in horizontal cells, specific somata of bipolar and amacrine cells, and cellular processes in all the strata of the inner plexiform layer. Somata and processes were also highly immunoreactive in the ganglion cell layer and astrocytes in the nerve fiber layer in all animals. In the P23H rat retinas, the TRPC1 distribution pattern changed according to advancing photoreceptor degeneration and the gliosis reaction, with TRPC1 immunoreactive Müller cells mainly in advanced stages of disease. The cellular TRPC1 immunoreactivity found in this work suggests different mechanisms of activation of these channels depending on the cell type. Furthermore, the results support the idea that photoreceptor loss due to RP is associated with robust TRPC1 protein expression in the rat inner retina and raise the possibility of TRPC1 channels contributing to maintain high basal calcium levels during neurodegeneration and/or maintenance processes of the inner retina.
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Affiliation(s)
- Elena Caminos
- University of Castilla-La Mancha, Department of Medical Science, Medical School of Albacete, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Albacete, Spain.
| | - Marina Murillo-Martínez
- University of Castilla-La Mancha, Department of Medical Science, Medical School of Albacete, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Albacete, Spain.
| | - María García-Belando
- University of Castilla-La Mancha, Department of Medical Science, Medical School of Albacete, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Albacete, Spain.
| | - José Julio Cabanes-Sanchís
- University of Castilla-La Mancha, Department of Medical Science, Medical School of Albacete, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Albacete, Spain.
| | - Juan R Martinez-Galan
- University of Castilla-La Mancha, Department of Medical Science, Medical School of Albacete, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Albacete, Spain.
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Hughes S, Foster RG, Peirson SN, Hankins MW. Expression and localisation of two-pore domain (K2P) background leak potassium ion channels in the mouse retina. Sci Rep 2017; 7:46085. [PMID: 28443635 PMCID: PMC5405414 DOI: 10.1038/srep46085] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/11/2016] [Accepted: 03/10/2017] [Indexed: 12/11/2022] Open
Abstract
Two-pore domain (K2P) potassium channels perform essential roles in neuronal function. These channels produce background leak type potassium currents that act to regulate resting membrane potential and levels of cellular excitability. 15 different K2P channels have been identified in mammals and these channels perform important roles in a wide number of physiological systems. However, to date there is only limited data available concerning the expression and role of K2P channels in the retina. In this study we conduct the first comprehensive study of K2P channel expression in the retina. Our data show that K2P channels are widely expressed in the mouse retina, with variations in expression detected at different times of day and throughout postnatal development. The highest levels of K2P channel expression are observed for Müller cells (TWIK-1, TASK-3, TRAAK, and TREK-2) and retinal ganglion cells (TASK-1, TREK-1, TWIK-1, TWIK-2 and TWIK-3). These data offer new insight into the channels that regulate the resting membrane potential and electrical activity of retinal cells, and suggests that K2P channels are well placed to act as central regulators of visual signalling pathways. The prominent role of K2P channels in neuroprotection offers novel avenues of research into the treatment of common retinal diseases.
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Affiliation(s)
- Steven Hughes
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Russell G. Foster
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Stuart N. Peirson
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
| | - Mark W. Hankins
- The Nuffield Laboratory of Ophthalmology, Sleep and Circadian Neuroscience Institute, Nuffield Department of Clinical Neurosciences, University of Oxford, Sir William Dunn School of Pathology, OMPI G, South Parks Road, Oxford, OX1 3RE, UK
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Li Q, Cui P, Miao Y, Gao F, Li XY, Qian WJ, Jiang SX, Wu N, Sun XH, Wang Z. Activation of group I metabotropic glutamate receptors regulates the excitability of rat retinal ganglion cells by suppressing Kir and I h. Brain Struct Funct 2016; 222:813-830. [PMID: 27306787 DOI: 10.1007/s00429-016-1248-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2015] [Accepted: 06/05/2016] [Indexed: 10/21/2022]
Abstract
Group I metabotropic glutamate receptor (mGluR I) activation exerts a slow postsynaptic excitatory effect in the CNS. Here, the issues of whether and how this receptor is involved in regulating retinal ganglion cell (RGC) excitability were investigated in retinal slices using patch-clamp techniques. Under physiological conditions, RGCs displayed spontaneous firing. Extracellular application of LY367385 (10 µM)/MPEP (10 µM), selective mGluR1 and mGluR5 antagonists, respectively, significantly reduced the firing frequency, suggesting that glutamate endogenously released from bipolar cells constantly modulates RGC firing. DHPG (10 µM), an mGluR I agonist, significantly increased the firing and caused depolarization of the cells, which were reversed by LY367385, but not by MPEP, suggesting the involvement of the mGluR1 subtype. Intracellular Ca2+-dependent PI-PLC/PKC and calcium/calmodulin-dependent protein kinase II (CaMKII) signaling pathways mediated the DHPG-induced effects. In the presence of cocktail synaptic blockers (CNQX, D-AP5, bicuculline, and strychnine), which terminated the spontaneous firing in both ON and OFF RGCs, DHPG still induced depolarization and triggered the cells to fire. The DHPG-induced depolarization could not be blocked by TTX. In contrast, Ba2+, an inwardly rectifying potassium channel (Kir) blocker, and Cs+ and ZD7288, hyperpolarization-activated cation channel (I h) blockers, mimicked the effect of DHPG. Furthermore, in the presence of Ba2+/ZD7288, DHPG did not show further effects. Moreover, Kir and I h currents could be recorded in RGCs, and extracellular application of DHPG indeed suppressed these currents. Our results suggest that activation of mGluR I regulates the excitability of rat RGCs by inhibiting Kir and I h.
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Affiliation(s)
- Qian Li
- Institutes of Brain Science, Fudan University, 138 Yixueyuan Rd, Shanghai, 200032, China.,Institute of Neurobiology, Fudan University, Shanghai, 200032, China.,State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China.,Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Peng Cui
- Institutes of Brain Science, Fudan University, 138 Yixueyuan Rd, Shanghai, 200032, China.,Institute of Neurobiology, Fudan University, Shanghai, 200032, China.,State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China.,Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Yanying Miao
- Institutes of Brain Science, Fudan University, 138 Yixueyuan Rd, Shanghai, 200032, China.,Institute of Neurobiology, Fudan University, Shanghai, 200032, China.,State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China.,Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Feng Gao
- Institutes of Brain Science, Fudan University, 138 Yixueyuan Rd, Shanghai, 200032, China.,Eye & ENT Hospital, Fudan University, Shanghai, 200031, China.,State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, 200031, China.,Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Xue-Yan Li
- Institutes of Brain Science, Fudan University, 138 Yixueyuan Rd, Shanghai, 200032, China.,Institute of Neurobiology, Fudan University, Shanghai, 200032, China.,State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China.,Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Wen-Jing Qian
- Institutes of Brain Science, Fudan University, 138 Yixueyuan Rd, Shanghai, 200032, China.,Institute of Neurobiology, Fudan University, Shanghai, 200032, China.,State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China.,Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Shu-Xia Jiang
- Institutes of Brain Science, Fudan University, 138 Yixueyuan Rd, Shanghai, 200032, China.,Institute of Neurobiology, Fudan University, Shanghai, 200032, China.,State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China.,Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Na Wu
- Institutes of Brain Science, Fudan University, 138 Yixueyuan Rd, Shanghai, 200032, China.,Eye & ENT Hospital, Fudan University, Shanghai, 200031, China.,State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China.,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, 200031, China.,Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China
| | - Xing-Huai Sun
- Institutes of Brain Science, Fudan University, 138 Yixueyuan Rd, Shanghai, 200032, China. .,Eye & ENT Hospital, Fudan University, Shanghai, 200031, China. .,State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China. .,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, 200031, China. .,Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China.
| | - Zhongfeng Wang
- Institutes of Brain Science, Fudan University, 138 Yixueyuan Rd, Shanghai, 200032, China. .,Eye & ENT Hospital, Fudan University, Shanghai, 200031, China. .,Institute of Neurobiology, Fudan University, Shanghai, 200032, China. .,State Key Laboratory of Medical Neurobiology, Fudan University, Shanghai, 200032, China. .,Shanghai Key Laboratory of Visual Impairment and Restoration, Fudan University, Shanghai, 200031, China. .,Collaborative Innovation Center for Brain Science, Fudan University, Shanghai, 200032, China.
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