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Charish J, Shabanzadeh AP, Chen D, Mehlen P, Sethuramanujam S, Harada H, Bonilha VL, Awatramani G, Bremner R, Monnier PP. Neogenin neutralization prevents photoreceptor loss in inherited retinal degeneration. J Clin Invest 2020; 130:2054-2068. [PMID: 32175920 DOI: 10.1172/jci125898] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2018] [Accepted: 01/14/2020] [Indexed: 02/05/2023] Open
Abstract
Inherited retinal degenerations (IRDs) are characterized by the progressive loss of photoreceptors and represent one of the most prevalent causes of blindness among working-age populations. Cyclic nucleotide dysregulation is a common pathological feature linked to numerous forms of IRD, yet the precise mechanisms through which this contributes to photoreceptor death remain elusive. Here we demonstrate that cAMP induced upregulation of the dependence receptor neogenin in the retina. Neogenin levels were also elevated in both human and murine degenerating photoreceptors. We found that overexpressing neogenin in mouse photoreceptors was sufficient to induce cell death, whereas silencing neogenin in degenerating murine photoreceptors promoted survival, thus identifying a pro-death signal in IRDs. A possible treatment strategy is modeled whereby peptide neutralization of neogenin in Rd1, Rd10, and Rho P23H-knockin mice promotes rod and cone survival and rescues visual function as measured by light-evoked retinal ganglion cell recordings, scotopic/photopic electroretinogram recordings, and visual acuity tests. These results expose neogenin as a critical link between cAMP and photoreceptor death, and identify a druggable target for the treatment of retinal degeneration.
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Affiliation(s)
- Jason Charish
- Vision Division, Krembil Research Institute, Toronto, Ontario, Canada.,Department of Physiology and
| | - Alireza P Shabanzadeh
- Vision Division, Krembil Research Institute, Toronto, Ontario, Canada.,Department of Anatomy, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Danian Chen
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.,Research Laboratory of Ophthalmology and Vision Sciences, State Key Laboratory of Biotherapy and.,Department of Ophthalmology, West China Hospital, Sichuan University, Chengdu, China
| | - Patrick Mehlen
- Apoptosis, Cancer and Development Laboratory, INSERM U1052, CNRS UMR5286, Université de Lyon, Lyon, France
| | | | - Hidekiyo Harada
- Vision Division, Krembil Research Institute, Toronto, Ontario, Canada
| | - Vera L Bonilha
- Cole Eye Institute, Cleveland Clinic, Cleveland, Ohio, USA
| | - Gautam Awatramani
- Department of Biology, University of Victoria, Victoria, British Columbia, Canada
| | - Rod Bremner
- Lunenfeld-Tanenbaum Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada.,Department of Laboratory Medicine and Pathobiology and.,Department of Ophthalmology and Vision Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Philippe P Monnier
- Vision Division, Krembil Research Institute, Toronto, Ontario, Canada.,Department of Physiology and.,Department of Ophthalmology and Vision Science, Faculty of Medicine, University of Toronto, Toronto, Ontario, Canada
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cAMP and Photoreceptor Cell Death in Retinal Degeneration. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2020; 1185:301-304. [PMID: 31884628 DOI: 10.1007/978-3-030-27378-1_49] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Inherited retinal degenerations (IRDs) are a genetically heterogeneous group of disorders characterized by the progressive loss of photoreceptor cells. Despite this heterogeneity in the disease-causing mutation, common underlying mechanisms promoting photoreceptor cell death may be present. Dysregulation of photoreceptor cyclic nucleotide signaling may be one such common feature differentiating healthy from diseased photoreceptors. Here we review evidence that elevated retinal cAMP levels promote photoreceptor death and are a common feature of numerous animal models of IRDs. Improving our understanding of how cAMP levels become elevated and identifying downstream effectors may prove important for the development of therapeutics that will be applicable to multiple forms of the disease.
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Abstract
Retinal degeneration, either acquired or inherited, is a major cause of visual impairment and blindness in humans. Inherited retinal degeneration comprises a large group of diseases that result in the loss of photoreceptor cells. To date, 131 retinal disease loci have been identified, and 76 of the genes at these loci have been isolated (RetNet Web site). Several of these genes were first considered candidates because of their chromosomal localization or homology to genes involved in retinal degeneration in other organisms. In this review, I will discuss recent advances in the identification of genes that cause retinal degeneration, and I will describe the mechanisms of photoreceptor death and potential treatments for retinal degenerative diseases.
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Affiliation(s)
- S Lev
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel.
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Denton TL, Yamashita CK, Farber DB. The effects of light on cyclic nucleotide metabolism of isolated cone photoreceptors. Exp Eye Res 1992; 54:229-37. [PMID: 1348477 DOI: 10.1016/s0014-4835(05)80212-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
A procedure has been developed for the isolation of cone photoreceptors from the retina of the lizard Anolis carolinensis in order to study the effects of dark- and light-adaptation on the cyclic nucleotide metabolism of these visual cells. Incubation of the retina in N2 medium with hyaluronidase and DNAase allows us to obtain intact photoreceptors with good purity (85-90%), yields (greater than 2 x 10(5) cells per retina), and more than 95% of them excluding Trypan blue. cAMP levels are 20-fold higher than cGMP levels in cells from dark-adapted animals and are decreased by 35% upon exposure to light, whereas cGMP levels show no apparent change. However, both cAMP- and cGMP-phosphodiesterases, as well as adenylate and guanylate cyclase, are activated several-fold by light, but the enzymes involved in cGMP metabolism have higher Vmaxs than the cAMP related enzymes. The apparent constant levels of cGMP found in cone photoreceptors may result from our inability to detect the very fast changes that occur in these cells when they are exposed to light.
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Affiliation(s)
- T L Denton
- Jules Stein Eye Institute, UCLA School of Medicine 90024-7008
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Palmer GC, Wilson GL, Chronister RB. Streptozotocin-induced diabetes produces alterations in adenylate cyclase in rat cerebrum, cerebral microvessels and retina. Life Sci 1983; 32:365-74. [PMID: 6131368 DOI: 10.1016/0024-3205(83)90082-6] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Eight weeks following streptozotocin-induced diabetes mellitus in rats, the sensitivity of adenylate cyclase to dopamine (DA) and norepinephrine (NE) was reduced in homogenates of retina. Furthermore, the activation of adenylate cyclase in cerebral microvessels (capillaries) by NE, 5'-guanylyl imidodiphosphate (alone or with NE) and forskolin was reduced in diabetic rats versus appropriate controls. In diabetic rats enzyme sensitivity to only NE was attenuated in homogenates of cerebral cortex and cortical piaarachnoid. No differences between controls and diabetics were noted with respect to guanylate cyclase or cyclic AMP phosphodiesterases. The damage observed in retina and microvessels may play an important pathogenic role in diabetes-induced blindness and stroke.
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