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Wu J, Jo DH, Fruttiger M, Kim JH. Cone cell dysfunction attenuates retinal neovascularization in oxygen-induced retinopathy mouse model. J Neurosci Res 2024; 102:e25316. [PMID: 38415926 DOI: 10.1002/jnr.25316] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2023] [Revised: 01/21/2024] [Accepted: 02/19/2024] [Indexed: 02/29/2024]
Abstract
Aberrant neovascularization is the most common feature in retinopathy of prematurity (ROP), which leads to the retinal detachment and visual defects in neonates with a low gestational age eventually. Understanding the regulation of inappropriate angiogenic signaling benefits individuals at-risk. Recently, neural activity originating from the specific neural activity has been considered to contribute to retinal angiogenesis. Here, we explored the impact of cone cell dysfunction on oxygen-induced retinopathy (OIR), a mouse model commonly employed to understand retinal diseases associated with abnormal blood vessel growth, using the Gnat2cpfl3 (cone photoreceptor function loss-3) strain of mice (regardless of the sex), which is known for its inherent cone cell dysfunction. We found that the retinal avascular area, hypoxic area, and neovascular area were significantly attenuated in Gnat2cpfl3 OIR mice compared to those in C57BL/6 OIR mice. Moreover, the HIF-1α/VEGF axis was also reduced in Gnat2cpfl3 OIR mice. Collectively, our results indicated that cone cell dysfunction, as observed in Gnat2cpfl3 OIR mice, leads to attenuated retinal neovascularization. This finding suggests that retinal neural activity may precede and potentially influence the onset of pathological neovascularization.
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Affiliation(s)
- Jun Wu
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Dong Hyun Jo
- Department of Anatomy and Cell Biology, Seoul National University College of Medicine, Seoul, Republic of Korea
| | - Marcus Fruttiger
- UCL Institute of Ophthalmology, University College London, London, UK
| | - Jeong Hun Kim
- Fight Against Angiogenesis-Related Blindness (FARB) Laboratory, Biomedical Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
- Department of Biomedical Sciences, Seoul National University College of Medicine, Seoul, Republic of Korea
- Department of Ophthalmology, Seoul National University College of Medicine, Seoul, Republic of Korea
- Global Excellence Center for Gene & Cell Therapy (GEC-GCT), Seoul National University Hospital, Seoul, Republic of Korea
- Institute of Reproductive Medicine and Population, Seoul National University College of Medicine, Seoul, Republic of Korea
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Adhikari RD, Kossoff AM, Cornwall MC, Makino CL. Bicarbonate boosts flash response amplitude to augment absolute sensitivity and extend dynamic range in murine retinal rods. Front Mol Neurosci 2023; 16:1125006. [PMID: 37122625 PMCID: PMC10140344 DOI: 10.3389/fnmol.2023.1125006] [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: 12/15/2022] [Accepted: 03/15/2023] [Indexed: 05/02/2023] Open
Abstract
Rod photoreceptors in the retina adjust their responsiveness and sensitivity so that they can continue to provide meaningful information over a wide range of light intensities. By stimulating membrane guanylate cyclases in the outer segment to synthesize cGMP at a faster rate in a Ca2+-dependent fashion, bicarbonate increases the circulating "dark" current and accelerates flash response kinetics in amphibian rods. Compared to amphibian rods, mammalian rods are smaller in size, operate at a higher temperature, and express visual cascade proteins with somewhat different biochemical properties. Here, we evaluated the role of bicarbonate in rods of cpfl3 mice. These mice are deficient in their expression of functional cone transducin, Gnat2, making cones very insensitive to light, so the rod response to light could be observed in isolation in electroretinogram recordings. Bicarbonate increased the dark current and absolute sensitivity and quickened flash response recovery in mouse rods to a greater extent than in amphibian rods. In addition, bicarbonate enabled mouse rods to respond over a range that extended to dimmer flashes. Larger flash responses may have resulted in part from a bicarbonate-induced elevation in intracellular pH. However, high pH alone had little effect on flash response recovery kinetics and even suppressed the accelerating effect of bicarbonate, consistent with a direct, modulatory action of bicarbonate on Ca2+- dependent, membrane guanylate cyclase activity.
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Flood MD, Veloz HLB, Hattar S, Carvalho-de-Souza JL. Robust visual cortex evoked potentials (VEP) in Gnat1 and Gnat2 knockout mice. Front Cell Neurosci 2022; 16:1090037. [PMID: 36605613 PMCID: PMC9807669 DOI: 10.3389/fncel.2022.1090037] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/04/2022] [Accepted: 12/05/2022] [Indexed: 12/24/2022] Open
Abstract
Intrinsically photosensitive retinal ganglion cells (ipRGCs) express the photopigment melanopsin, imparting to themselves the ability to respond to light in the absence of input from rod or cone photoreceptors. Since their discovery ipRGCs have been found to play a significant role in non-image-forming aspects of vision, including circadian photoentrainment, neuroendocrine regulation, and pupillary control. In the past decade it has become increasingly clear that some ipRGCs also contribute directly to pattern-forming vision, the ability to discriminate shapes and objects. However, the degree to which melanopsin-mediated phototransduction, versus that of rods and cones, contributes to this function is still largely unknown. Earlier attempts to quantify this contribution have relied on genetic knockout models that target key phototransductive proteins in rod and cone photoreceptors, ideally to isolate melanopsin-mediated responses. In this study we used the Gnat1-/-; Gnat2cpfl3/cpfl3 mouse model, which have global knockouts for the rod and cone α-transducin proteins. These genetic modifications completely abolish rod and cone photoresponses under light-adapted conditions, locking these cells into a "dark" state. We recorded visually evoked potentials in these animals and found that they still showed robust light responses, albeit with reduced light sensitivity, with similar magnitudes to control mice. These responses had characteristics that were in line with a melanopsin-mediated signal, including delayed kinetics and increased saturability. Additionally, we recorded electroretinograms in a sub-sample of these mice and were unable to find any characteristic waveform related the activation of photoreceptors or second-order retinal neurons, suggesting ipRGCs as the origin of light responses. Our results show a profound ability for melanopsin phototransduction to directly contribute to the primary pattern-forming visual pathway.
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Affiliation(s)
- Michael D. Flood
- Department of Anesthesiology, College of Medicine, The University of Arizona, Tucson, AZ, United States
| | - Hannah L. B. Veloz
- Department of Anesthesiology, College of Medicine, The University of Arizona, Tucson, AZ, United States
| | - Samer Hattar
- Section on Light and Circadian Rhythms (SLCR), National Institute of Mental Health, Bethesda, MD, United States
| | - Joao L. Carvalho-de-Souza
- Department of Anesthesiology, College of Medicine, The University of Arizona, Tucson, AZ, United States,Department of Physiology, College of Medicine, The University of Arizona, Tucson, AZ, United States,Department of Ophthalmology and Vision Science, College of Medicine, The University of Arizona, Tucson, AZ, United States,BIO5 Institute, The University of Arizona, Tucson, AZ, United States,*Correspondence: Joao L. Carvalho-de-Souza,
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